tag:blogger.com,1999:blog-39400385908265740072024-03-12T19:21:01.115-07:00Science through my eyesJackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.comBlogger28125tag:blogger.com,1999:blog-3940038590826574007.post-14430931280825248232013-01-05T07:59:00.002-08:002013-01-05T07:59:55.397-08:00Legal vs Moral Duty of CareIf a doctor is driving past the scene of an accident, do they have an obligation to stop and help?<br />
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According to the law in the UK, no. Duty of care only applies where you have actually created the situation through which someone may get hurt. An example of this is driving: the driver has a duty of care to the other road users not to let them come to harm as a result of their actions.<br />
<br />
If the doctor chooses to ignore someone who is hurt, then it is called a 'pure omission', and they are not doing anything wrong in the eyes of the law. Similarly, the GMC does not list anything about treating people who are not your patients in the "<a href="http://www.gmc-uk.org/guidance/good_medical_practice/duties_of_a_doctor.asp">duties of a doctor</a>"; however, doctors "also have a duty to the health of the wider community<span style="color: #333333; font-family: Verdana, Arial, sans-serif; font-size: x-small;">"</span><span style="color: #333333; font-family: inherit; font-size: x-small;">, </span><span style="color: #333333; font-family: inherit;">according to the section on responsibilities from the same website. The use of the word community seems to imply that this doesn't apply to harmed individuals, but rather the potential for harm to come to other people.</span><br />
<span style="color: #333333; font-family: inherit;"><br /></span>
<span style="color: #333333; font-family: inherit;">And yet, if you use the ethical framework I outlined a while ago, it always seems moral to go and help someone in distress (with the exception of the fact that it may not give them much autonomy; however the other 3 principles override that in this case). So while you have no obligation to do it legally, it is the right thing to do. Does that mean you have a <i>moral</i> obligation? I would argue that you do, on the grounds that you are faced with two options: help, or leave. One is morally correct, and the other is wrong. Therefore, anyone who can help should help, regardless of what the law says. </span><br />
<span style="color: #333333; font-family: inherit;"><br /></span>
<span style="color: #333333; font-family: inherit;">If and when someone does go and help to treat a person who has been injured, it could then be argued that the injured person is a patient, and if anything goes wrong while their rescuer is helping them, it can legally be blamed on the rescuer, even though without them, they might have been in an even worse state. </span><br />
<span style="color: #333333; font-family: inherit;"><br /></span>
<span style="color: #333333; font-family: inherit;">So it's tricky: help someone in need and face recriminations if you don't get it right, or leave them alone and wait for someone who has a contractual obligation (paramedics, etc). So far, I've never been in a situation like that, but I hope that when the time comes, I'll be able to recognise my skill set without bias and do the right thing.</span>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-12050494990523356382012-11-25T07:47:00.000-08:002012-11-25T07:47:30.143-08:00The Mind ReaderRecently on the BBC was a program called "<a href="http://www.bbc.co.uk/programmes/b01ny377">The Mind Reader</a>". It followed the families of several patients with brain injuries that had left them without control of their muscles or speech centres; although in every case they clearly loved and cared for their children very much, it was impossible for them to know how much they understood.<div>
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Each family coped with this in a slightly different way - one explained to their son who he was every time they saw him, another tried to discern if their son could respond through his thumbs and eyes, and a third talked to theirs like they would talk to anyone, regardless of whether he understood or not. This uncertainty was one of the things that struck me the most about the lives of the families - no one could help them find out whether their affection was falling on deaf ears, and if anyone could, would they want to know? </div>
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Finding out if these patients are conscious has big implications for everyone involved. Their carers and families, if they are not aware of their surroundings, could feel as if they have been wasting their time and their love. Are they still human if they cannot experience human emotion, cannot perceive anything? This is not a question to be answered with a simple yes or no. Similarly, if the person is conscious, but cannot communicate to those people who they love and are loved by, what can be done to improve their lives? Is it easier for the family to know whether or not they can understand, or is ignorance truly bliss?<br /></div>
<div>
A scientist called Professor Owen, who has worked on various issues surrounding consciousness in the past, has devised a way of discerning whether a person is capable of responding to questions. Using an fMRI scanner, he monitors their brain activity and asks them to imagine certain scenarios. Humans use the same areas of the brain to imagine doing something as they do when they are actually doing something, and so by imagining different things, you can produce distinctly separate brain activity patterns. The two things Prof. Owen asked the patients to imagine were playing tennis and walking around their house. </div>
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Not all of the patients in the group shadowed by the BBC appeared to be conscious. One person in particular did not respond at all when asked to imagine playing tennis in the fMRI scanner. The parents were incredibly gracious about it, and while they were thankful to the doctors for providing them with answers, they were left with the conundrum of how to carry on. Leaving their son seems barbaric, and I don't think any of the families in the program even considered that as an option; at the same time, carrying on when there is very little chance of it having an effect must be very, very difficult. But carry on they did, and even if it was not received, I think the parents were comforted by still having their son anyway - talking helped them more than anyone else.</div>
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However, some people could respond to Prof. Owen's stimuli. Seeing the reactions on the faces of the friends and family of those patients was amazing, and reminded me of why I want to become a doctor, for moments like that, where you can make such a profound difference to someone's life through research and treatment. Having established that they could respond, the professor asked them a few questions to find out how much of their world they were aware of. One person, Scott Routley, who had been considered unresponsive for 12 years following an accident, answered yes/no questions through imagining different things, conveying that he remembered events from before and after the accident. The next question they asked Scott was whether he was in pain. This question is central to the care of patients in PVS - if they are conscious, unable to respond, and in constant pain, is it really more kind to continue caring for them? If the answer was yes, and he was in pain, Scott was asked to imagine playing tennis. If the answer was no, when prompted, he would imagine walking around his house. </div>
<div>
Professor Owen asked the question. A prerecorded voice chimes in: "imagine" - the prompt for Scott to respond. The virtual model of his brain flashes red in the upper right of the screen. He has imagined walking around his house. </div>
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It's important to remember that not all PVS patients are conscious: in Prof. Owen's experience so far, "about 20% appear to be". However, just being able to answer simple questions is the first step down a road towards communicating with people who have no other way, who are locked in but can't tell anyone. Hopefully the technology can be used to better their care and treatment by giving the doctors, nurses and family members who look after them some feedback on what they want.</div>
Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-52907621036333015162012-10-28T14:37:00.001-07:002012-10-28T14:38:19.318-07:00Bond Chemistry <div class="separator" style="clear: both; text-align: center;">
<a href="http://collider.com/wp-content/uploads/daniel-craig-skyfall3.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="213" src="http://collider.com/wp-content/uploads/daniel-craig-skyfall3.jpg" width="320" /></a></div>
Today, I watched Skyfall, the new Bond film. It's a fantastic film, with gorgeous actors, actresses, cars and explosions abound. I would do a post critiquing it and examining the themes throughout, but that's not what this blog is for, and it'd just be a drop in the online ocean of fan-made reviews of films they've just seen.<br />
<br />
So instead, I thought I'd look into the sciencey medically bit that intrigued me. The main villain is revealed to have bitten a cyanide pill in the past, which failed to kill him; he now has very few teeth and has to wear a false set. When he takes them off, the muscles in his face seem to sag, and the lower half of his eyeball is revealed, as if someone had pulled down on the skin around his cheek, seemingly because his dentures also include supports for his maxilla or something.<br />
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But what I thought I knew about cyanide was that it works by inhibition of one of the enzymes used in respiration. Could it really eat away at the inside of your mouth? The first clue was in the name of the actual chemical inside cyanide pills, hydrogen cyanide. This tells you that it is a compound of the formula HX, where X is some negative ion (here, it is cyanide). These kind of compounds dissociate in solution to form H+ ions and X- ions. They're also known as acids. In this case, the "X" is cyanide, which forms CN- ions; this is what inhibits the respiratory enzyme.<br />
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It is conceivable that, because it is an acid, it could erode the teeth and bone away (acid erosion of teeth is permanent, at least). For this to happen, you would need an acid of a very low pH, and in sufficient quantities that it can react with enough teeth.<br />
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Now for some wild assumptions and quick calculations:<br />
The fatal dose of cyanide, according to <a href="http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/cyanide-cyanure/index-eng.php">Health Canada</a>, is about 1.52mg/kg bw. So for the sake of argument, we will say that he took as close to the fatal dose as possible without it being fatal. Celebritiesheightandweight.com <a href="http://www.celebritiesheight.com/javier-bardem-height-and-weight/">helpfully informs us</a> that Javier Bardem, the actor playing Silva, weighs 84 kg. Therefore in order to be just non-lethal, the pill would have to contain 127.68mg of cyanide ions. The Mr of CN is 26, so the lethal amount of HCN is 0.004910769231 moles.<br />
The pill was stored in his 2nd molar, which we will model as a <a href="http://en.wikident.org/wiki/Average_tooth_sizes">9mm*9mm*7mm</a> cuboid (assuming it is on the upper jaw); therefore its volume is 0.000567dm^3. The pill would have had to have taken up much of this space in order to be easily accessible, so we can say that the pill has the same dimensions as the molar. Therefore the concentration of HCN (which used to be known as prussic acid, on an unrelated note), is 8.660968661moldm^-3.<br />
Hydrogen cyanide's <a href="http://en.wikipedia.org/wiki/Hydrogen_cyanide">pKa is 9.2</a>. Therefore its acid dissociation constant is 10^(-9.2). This is [H+][CN-]/[HCN]. Given that the concentrations of H+ ions and CN- ions are the same (because they dissociate in a 1:1 ratio), and given the concentration of HCN, it is possible to work out the concentration of H+ ions:<br />
<div style="text-align: center;">
[H+][CN-]/[HCN] = 10^(-9.2)<br />
[H+] = [CN-], therefore ([H+]^2)/[HCN] = 10^(-9.2)<br />
[HCN] = 8.660968661, therefore [H+]^2 = 8.660968661*10^(-9.2)<br />
Therefore [H+] = sqrt(8.660968661*10^(-9.2))<br />
[H+] = 7.392362131*10^(-5)</div>
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Therefore pH (= -log[H+]) = 4.131216766</div>
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= 4.13 to 2 decimal places<br />
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<a href="http://en.wikipedia.org/wiki/Acid_erosion">Wikipedia says</a> that there is a paper saying that solutions with pH<5.0-5.7 cause dental erosion. Therefore, Silva's pill may well have damaged his teeth. However, it seems unlikely that it could have destroyed so much of his jaw and face: the pH of wine, for instance, is around 3-4. So the acidic effect of the cyanide pill would actually be less than if you just squirted the inside of your mouth with some <a href="http://www.ajevonline.org/content/33/2/75.abstract">sauvignon blanc</a>.</div>
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Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-91195002876310013582012-10-28T11:27:00.000-07:002012-10-28T14:39:00.478-07:00Pathology project news againThe medlink team have got back in touch; the paper I wrote last year is going to be published in their collection! Woooooooo!<br />
...Not quite a peer-reviewed journal, but I'll take what I can get.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-78485885577330536742012-09-08T13:25:00.002-07:002012-09-08T13:27:25.057-07:00Prayer as an element of medicine<br />
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<o:p> </o:p><span style="text-indent: 36pt;">James records in his gospel that “the prayer of
faith shall save the sick” </span><sup style="text-indent: 36pt;">1</sup><span style="text-indent: 36pt;">, and according to the U.S. Centre for
disease control and prevention, 45% of adults use prayer for personal health
reasons in the modern age.</span><sup style="text-indent: 36pt;">2</sup><span style="text-indent: 36pt;"> Unfortunately, it is very difficult to
measure the power of prayer as a part of the treatment of someone, for quite a
number of reasons: firstly, because some religious groups claim that praying as
part of a scientific study is artificial, so the prayers will not be answered.
There are also various confounding variables, such as ability to pray
(according to some, prayer is a skill to be learned</span><sup style="text-indent: 36pt;"> </sup><span style="text-indent: 36pt;">)</span><sup style="text-indent: 36pt;">3</sup><span style="text-indent: 36pt;">
and fervour of prayer (this may affect the effectiveness of prayer)</span><sup style="text-indent: 36pt;">4</sup><span style="text-indent: 36pt;">.
Another reason that it is difficult to study is that it receives very little
funding; according to the Washington Post, “about $5 million is spent worldwide
on such research”</span><sup style="text-indent: 36pt;">5</sup><span style="text-indent: 36pt;">. Critics of scientific study of prayer argue that
part of the point of prayer is that it is not always answered, and that god is
not a mechanism that responds in a way that is predictable, or even measurable,
by humans. For these reasons, and because in such a religiously charged
subject, some studies are bound to be biased, research into prayer is still
very much being refined, and there are conflicting results at the moment.</span></div>
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<o:p></o:p></div>
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There have been three main types of prayer studied scientifically to
gauge their efficacy. The most obvious one is second person prayer, which is
performed by someone who knows the person they are praying about. Second person
prayers directly ask a higher power for the person to be helped, as do third
person prayers, which are performed by a stranger. First person prayer not only
includes the petition to god but also can include self-meditation beforehand,
and is a separate type of prayer.<o:p></o:p></div>
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<a name='more'></a><br /></div>
<h4>
Third person prayer and divine
intervention<o:p></o:p></h4>
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In order to test second and third person prayers, both blinded and
non-blinded experiments have been set up. The general format is as such: two
groups of people in hospital for similar problems are chosen (for example,
people with the same cancer). One group of people is prayed for, while the
other group is not. The health of the patients is measured, either using
variables like blood pressure and heart rate, or by more subjective measures
such as perceived comfort or number of visits required by a doctor. In third
party experiments, the patients are prayed for by strangers, whereas in second
person experiments, the friends and family are asked to pray for their loved
ones. Again, there is difficulty in ensuring that a fixed number of people are
praying - there is nothing stopping friends who are not part of the study from
asking for the patient's good health. In a blinded experiment, the only people that
know who is being prayed for are the people doing the praying, i.e. neither the
doctor nor the patient knows if the patient is being prayed for. This is the
most scientifically rigorous method; in non-blinded studies it is impossible to
rule out the placebo effect.<o:p></o:p></div>
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The best way to test whether there was any godly interference in aiding
a patient's recovery is a third party, blinded trial. These come as close to
having one independent variable as any prayer study can for a number of
reasons. Firstly, the people praying have no affiliation to the patient, rather
than having any personal attachment, so fervour of the prayer is not affected,
as it might be in second party studies, where there could be differing levels
of attachment to the patient by the people praying. Secondly, by artificially
selecting who is doing the praying, it is possible to ensure everyone is of the
same denomination, piety, and prayer skill level, simply by using one
congregation from the same church. This also allows participants to be randomly
selected, rather than only those with religious family and friends. Lastly,
because it is blinded, there is no chance that the placebo effect could
contribute to the findings. In experiments like this, there is also the
opportunity to test the effect of a "placebo prayer".<o:p></o:p></div>
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Despite the relatively
little amount of money spent on studying spiritual healing, there have been thousands
of studies in the past 30 years.<sup>5</sup> Not all of them fit these
criteria, however, and not all are published in peer reviewed journals, either.
One of the biggest and most thorough studies was STEP, the study on therapeutic
effects of prayer,<sup>6</sup> which studied 1802 patients recovering from the
same surgery in 6 different hospitals. There were three groups: two which were
told they may or may not receive intercessory prayer, and one which was told it
definitely would. Of the first two, one group received prayer and the other did
not. They were then monitored for 30 days following the surgery for any
complications. Significant events and deaths were also measured. The group
certain of receiving prayer had a 59% chance of complications. The two groups
uncertain had a 51% (if they were not prayed for) or 52% (if they were not)
chance of complications in the 30-day period. That is to say, there was no
significant difference between whether or not they were actually prayed for,
but knowing that they would be prayed for decreased the chance of an
uncomplicated recovery. Part of the reason that the STEP program was important
was because it is one of the few studies
that primarily looked for negative results (or the lack thereof). This
eliminates the bias prevalent in other studies towards looking for a benevolent
god; in those studies, the only outcomes are positive results or no significant
results. The existence of this bias highlights an interesting assumption in
prayer studies, which is that the results, if there are any, are presumed to be
beneficial to humans. The trial still did not address other issues, for example
it still treats god as an impersonal, mechanical being who responds in
calculable ways to given stimuli. Critics argue that there is no room for any
answer other than "yes, prayers are answered" or "no, prayers
are never answered"; there should be provisions for an answer along the
lines of "not now", or "not always". <sup>7</sup><o:p></o:p></div>
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There are also various
meta-analyses on the studies conducted in order to corroborate their
results. These reviews usually select
the literature they use with the criteria listed above, but some are more
strict, and there is also a comment on the methodology of each experiment in
the paper. The most recent results used 17 trials, and found significant effects
of prayer in 7 of them.<sup>8</sup> This is the general trend in such papers:
there is some evidence that religious healing helps the patient, but those
results tend to come from the more subjective measurements or less rigorous
trials.<sup>8</sup> Even these summaries of research are unclear and regularly
contradict each other, unfortunately. <o:p></o:p></div>
<h4>
First person prayer and meditation<o:p></o:p></h4>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC61046/bin/berl4739.f1.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="375" src="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC61046/bin/berl4739.f1.jpg" width="400" /></a></div>
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Even without miraculous help from a
god, it is conceivable that the actual act of prayer could have some
therapeutic effect. It was found that recitation of a Latin prayer or a mantra
increased heart rate variability and baroreflex sensitivity (the receptors that
effect changes in heart rate) in a 2001 study by Bernadi et al..<sup>9</sup>
This is known to be associated with better prognosis in heart conditions and is
a good indicator of exercise tolerance, and oxygenation of the blood, amongst
other things. The mechanism by which it effects this change is thought to be to
do with the rate of respiration and its synchronisation with other rhythms in
the body, such as rise and fall of blood pressure. It is known that a slow
respiratory rate decreases myocardial ischaemia, and the waves in blood
pressure are about 0.1 Hz, i.e. one every 10 seconds. Therefore, in order for
respiration to be synchronous with blood pressure, an ideal breathing rate
would be 6 breaths per minute. <o:p></o:p></div>
<div class="MsoNormal">
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</v:shape><![endif]--><!--[if !vml]--><!--[endif]--> In the Bernardi study, various
factors were measured during normal breathing, normal talking, and recitation of religious mantras. As is shown
in the figure, talking slowed down respiration, and recitation further slowed
it down and synchronised it with blood flow and blood pressure waves. <o:p></o:p></div>
<div class="MsoNormal">
Both the Ave Maria (in Latin) and a
yoga mantra were studied, in order to test whether the different disciplines
affected the results. Remarkably, both slowed the breathing down to almost 10
second cycles, or 6 per minute, which coincides with the spontaneous cycles of
blood pressure (see figure), which suggests that they both evolved to have
roughly the same rhythm. This breathing system also makes people feel calmer,
and so it makes sense for people to prefer those prayers, which is how they
have come in to common usage. There is also historical evidence that the
mantras of <st1:place w:st="on">India</st1:place>
influenced those of the middle east, which the crusaders then brought back to
the western world to form the Christian prayers that we still use today.
Therefore, there is some evidence that the act of saying some prayers is
physiologically beneficial, especially in people who have some form of heart
disease or are at risk of a heart attack.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Prayer is often recorded through
anecdotal evidence to be relaxing or empowering; it is more difficult to
measure psychological symptoms, but studies have also been conducted on this. For
example, in 1988, a study was conducted by Carlson et al., designed to test
stress reduction effects of meditative prayer compared to relaxation training
(and also a control group), using tension in the frontalis muscle and skin
temperature as indicators of anxiety.<sup>10</sup> It was found that this
meditation produced significantly more stress reduction than the control group
or the group undergoing relaxation training. It has been recorded, however,
that prayer is not always successful, particularly if done alone.<sup>11</sup>
This is because people praying alone are more likely to only dwell on their
guilt and failings, whereas in a group, there is a curative environment,
guidance and support from others in the group. Thus is it possible to pray
"incorrectly", from a medical point of view, although the
physiological mechanisms behind the psychological symptoms are still unclear;
it is associated with increased cortical activity, as when the body is alert (Levin,
2001), but little else is known.<o:p></o:p></div>
<div class="MsoNormal">
There is some further evidence that "integrating
prayer into day-to-day life" makes one a kinder, more empathic person.<sup>12</sup>
According to the study, based on qualitative judgements, they were less likely
to get very irate, and more likely to be more friendly towards others, even
individuals who were hard to get along with. This is probably because the same
group of people are more likely to live by the principles of their religion
(the trial only included Christians), which involves turning the other cheek
and not judging other people.<o:p></o:p></div>
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<h4>
<o:p> </o:p></h4>
<h4>
Conclusion<o:p></o:p></h4>
<div class="MsoNormal">
The current research into
intercessory prayer has inconclusive results, due in part to the methodology
and inherently supernatural nature of the trials. In general there does seem to
be a positive effect of distant prayer, although not statistically significant,
and potentially because of the way results are recorded. In order for studies
to progress, there needs to be an objective, quantitative measure of general
health, which can be measured as "good" or "bad", and
multiple repeats using different religions, methods of prayer, and levels of
ability of prayer. Even then it is unlikely such a trial would be accepted by
the religious community because of the problems with "artificial
prayer".<o:p></o:p></div>
<div class="MsoNormal">
Trials involving first person prayer
are more successful - stress is reduced by it and recitation of some prayers
helps to improve heart conditions and hypertension, amongst other things. There
is a proposed mechanism for the latter, but the former would merit more
research as well in order to help differentiate the biological methods of
prayer and relaxation training as a stress reducer. <o:p></o:p></div>
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<o:p></o:p></div>
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</span></b>
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<h4>
Bibliography<o:p></o:p></h4>
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1.James 5:15, King James Version<o:p></o:p></div>
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2.P.M. Barnes et al., "Complementary and
Alternative Medicine Use Among Adults: <st1:place w:st="on">United States</st1:place>, 2002", 2004<o:p></o:p></div>
<div class="MsoNormal" style="line-height: 150%;">
3.<span style="font-size: 13.5pt; line-height: 150%;"> </span>Pope Jean Paul II, <span style="font-size: 13.5pt; line-height: 150%;">"</span>Apostolic
letter<i>,</i> novo millennio ineunte",
2000<o:p></o:p></div>
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4. St. Louis de Montfort, "The secret of
the rosary", c.17th century <o:p></o:p></div>
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5. Michelle Boorstein, "Study of health
and religosity growing despite critiscism", 2008<o:p></o:p></div>
<div class="MsoNormal" style="line-height: 150%;">
6.<span style="font-size: 16.5pt; line-height: 150%; mso-ansi-language: EN-GB; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN; mso-font-kerning: 18.0pt;"> </span>Benson et al., "Study of the
Therapeutic Effects of Intercessory Prayer (STEP) in cardiac bypass patients: a
multicenter randomized trial of uncertainty and certainty of receiving
intercessory prayer", 2006</div>
<div class="MsoNormal" style="line-height: 150%;">
7. M. Jantos and H. Kiat, "Prayer as medicine: how much have we
learned?", 2007<o:p></o:p></div>
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8.<span style="background: white; font-family: Arial; font-size: 7.5pt; line-height: 150%;"> </span>D. R. Hodge, "A Systematic Review of the
Empirical Literature on Intercessory Prayer", 2007</div>
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9. Bernardi et al., "Effect of rosary
prayer and yoga mantras on autonomic cardiovascular rhythms: comparative study",
2001<o:p></o:p></div>
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10.<span style="color: windowtext; font-family: TimesNewRomanPSMT; font-size: 9.0pt; line-height: 150%; mso-ansi-language: EN-GB; mso-bidi-font-family: TimesNewRomanPSMT; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;"> </span>J. Martin and C. Carlson, "Spiritual dimensions
of health psychology", 1988<o:p></o:p></div>
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11.<span style="background: white; color: #222222; font-family: Arial;"> </span>Parker and St. Johns<span style="background: white; color: #222222; font-family: Arial;">, "</span>Prayer Can Change Your Life", 1957<o:p></o:p></div>
<div class="MsoNormal" style="line-height: 150%;">
12. S. Morgan, "A research note on
religion and morality: Are religious people nice people?", 1983<b><o:p></o:p></b></div>
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Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-29684955141937226222012-08-26T10:20:00.000-07:002012-08-26T10:20:23.345-07:00Fat acceptance<div class="separator" style="clear: both; text-align: center;">
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On the subject of ethics, here's an interesting topic. There is a <a href="http://en.wikipedia.org/wiki/Fat_acceptance_movement">movement</a>, now largely online, to end discrimination and prejudice against fat people, and whose proponents say that you can be healthy regardless of how big your waist is. According to the group, the health issues associated with obesity are exaggerated because of society's bias against fat people.<br />
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I used to be really really fattist (that has to be a word); it probably didn't help growing up in a family conscious of help, and with influences like my gran, who is hilariously un-PC about things like this. Nowadays, I care less, but I'd be lying if I said I didn't have a prejudice against people who are noticeably fat. This is unfair. Some people genuinely cannot help it - there are conditions like Ayazi syndrome that cause obesity almost irrespective of lifestyle. There are also many genes that predispose people towards putting on more weight, and of course anyone with parents who've grown up eating badly isn't likely to be skinny.<br />
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On the other hand, the vast majority (no pun intended - it would be unlike me to make jokes at someone else's expanse) of obese people don't have these conditions, but just don't look after themselves. If you have an abundance of cheap food, why would you not take advantage of it? Evolutionarily, that would make no sense. Or at least, in times of little to no food, that would make no sense. In today's world,it's those who can resist the urge to eat whatever is available that will outlive the others. As soon as you start blaming things you can't change for your weight, you lose the incentive to do anything about it at all - if all that's needed is willpower, first you have to recognise that you are the problem, not anyone else. This makes sense from a psychological point of view, in order to get in the right mindset, but it might not be fair to the person. Maybe, just maybe, it actually isn't their fault originally. The modern lifestyle is to eat lots of unhealthy, unbalanced food, and do a job that requires no physical exercise. It's no wonder, then, that there are so many problems caused by excess cholesterol, fat, or just weight, in the world today. Blaming someone for something that society encourages seems unfair, and so if that's the reason they got out of shape in the first place, then it isn't their fault. Could you say that it's due to the parents, who allow it to happen to their children? <a href="http://www.bbc.co.uk/news/health-12226744">Apparently</a>, they don't realise when it's happening; you could only blame them as much as you could a sleepwalker for knocking over a vase.<br />
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Which is why I agree with the fat acceptance movement to a degree: blaming people is effectively useless. It makes people feel worse about themselves, could lead to worse eating disorders, and encourages what is essentially bullying. But what I don't agree with about the whole thing is <a href="http://www.haescommunity.org/">this</a>. It's things like "Let's face it, we've lost the war against obesity" that really do have a bad effect on people's outlook, and that's unfair. Giving up yourself is perfectly okay, and if you're happy with your body then that's great. But if someone who was struggling to get their weight down saw a message like that, it would just eliminate all hope. That's taking away from someone else's potential good health (let's not skirt around the issue - being fat is the cause of a huge number of problems, and even deaths, globally, particularly in western countries).<br />
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I think that the cause is targeting individuals at all. Converting one person, or a hundred, or a thousand, to a healthy lifestyle is an impressive feat, but doesn't change the causes of the problem. If anything is to be done about it, governments and food producers need to work together to stop awful food being so readily available. The cheapest, most accessible food is also the highest in sat fats, sugar, salt and cholesterol, so it is possible to be almost unable to avoid becoming obese just on financial grounds. My master plan, should I take control of the world, would be a tax on fast food and meat, the money raised from which would go towards subsidising (currently more expensive) healthier food. Hopefully a scheme like that would be able to start to address the imbalance in health between different socio-economic classes.<br />
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So in summary, fat acceptance is a really great idea as long as it is a support group for people who are having problems with being bullied, but it should not in any means encourage becoming or staying fat; that goes against both what is good for the individual (non-maleficence) and what is good for society (justice) in that everyone has to pay for the problems that are brought about by avoidable means.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-39598632719599697692012-08-26T08:18:00.001-07:002012-08-26T10:21:35.004-07:00Gillon's 4 principles of medical ethicsDoctors are often asked to make decisions which have no immediately obvious "right" or "wrong" outcome. Of course, as a doctor, you sign up to do this, and you won't always need help; occasionally though, there are situations that really give one pause for thought, and when a systematic approach is necessary to ensure you have covered all bases.<br />
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The most common of these approaches (to my knowledge) is Gillon's 4 principles. The way to use this framework is to work through all of the effects of a decision relating to 4 given principles, and use that as a basis to decide what is the best thing to do. The areas to consider are: beneficence (what good can come of it), non maleficence (what harm could be avoided), autonomy (does it give everyone a choice), and justice (does it do good for the greater community). If it is impossible to decide having done this because all sides of the argument seem to be equal, then more weight is given to autonomy, because there is truly no moral difference between deciding one thing or another, so taking choice away would make any decision unnecessarily immoral.<br />
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<b>An example:</b> as an NHS doctor, someone comes in and says that they have injured their elbow playing tennis, which is stopping him from playing the sport, but doesn't bother him otherwise. The only treatment is a very expensive surgical procedure. He plays casually with his friends, and would like to start playing again.<br />
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Beneficence:<br />
It would allow him to start playing tennis again, which also encourages him to live a more healthy lifestyle.<br />
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Non-maleficence:<br />
Any surgery carries with it the risk of not waking up from the anaesthetics, and also the risk of a complication. There is no 100% guarantee it will go well.<br />
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Autonomy:<br />
Allowing the operation gives him the choice to get it done, which is what he wants.<br />
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Justice:<br />
It would be unfair to give him an expensive operation on the NHS because the same service couldn't be offered to everyone with that problem, just on a financial basis.<br />
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Final decision: here, justice and the chance that it could go wrong far outweigh beneficence and autonomy. However, in a situation where he was a professional tennis player, it would add strength to the beneficence side, which would make it better to give him the operation. Most of the time, doctors have guidelines to help them as well as these frameworks, so you wouldn't need to do this, but every so often there are exceptions to them as well.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-78479282386247154312012-08-19T10:59:00.002-07:002012-08-26T10:22:10.622-07:00Androgenic effects of steroids and why they can be less than greatYesterday I wrote a brief explanation of the anabolic effects of certain types of steroids, and mentioned the fact that they make you "more manly". The post was also almost an advertisement for the drugs, which was unintentional; I just haven't got on to why you probably shouldn't take them yet.<br />
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Rather than being called 'anabolic steroids', the full name of the subset of drugs I've been talking about is 'anabolic-androgenic steroids', or AAS. The whole group of effects that I omitted are represented by the second A. These have a much broader range than the anabolic ones, and change depending on gender and stage of development. They include enlargement of the clitoris and infant penis (bizarrely, it causes the opposite in adult males), testicles, increased body & facial hair, decreased actual hair, and changes in the voice & libido. In puberty they stunt growth (amongst other things), and in fetal development they lead to emphasised male features in females, and vice versa.<br />
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All of these effects are largely effected through transcription of various genes, like before with the increased muscle mass. However, the androgen receptors that the steroids bind to also mess around with proteins outside of the nucleus, which control ion transport in and out of cells.<br />
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What I really wanted to focus on in this post was the pros and cons of AAS. Obviously some people would view increased muscle mass as an advantage in its own right, and that definitely is a positive effect for body builders using them. In a medical setting, that particular use of the drugs are more helpful to people with problems that have led to them having a massively decreased muscle mass - AIDS and some cancers can have this effect. In such situations, it's important to give the patient as much help with getting enough muscle to be able to move, to help them help themselves. This applies to things like people rehabilitating part of their body after a long period of inaction (e.g. following surgery) as well.<br />
All AASes (definitely the correct plural form) have a ratio of anabolic to androgenic effects. It's worked out by castrating two groups of rats, giving one group the drug, then weighing the prostate gland and a specific muscle of all of them. The group without the drugs are used as a baseline, to work out the mean increase in mass of both - the increase of the prostate gland is representative of the androgenic effects and the muscle is representative of anabolism. With this information, doctors can select the drug that will have the effects they desire.<br />
AASes with proportionally higher levels of androgenic effects can help to treat diminished function of the testes, to boost a patient's levels of adrogens.<br />
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Onto the cons: one major downer on the whole thing is that steroids can cause hypertrophy not only of the skeletal muscles, but also of cardiac muscles. You then have the situation caused by hypertension, where there is too much muscle for the coronary arteries to support, so some muscle dies, which is a heart attack. On a more minor note, because AASes include testosterone, which increases oil production, users can get acne. An excess of testosterone gets converted into estradiol by an enzyme. Estradiol is typically a female hormone, and leads to gynecomastia - moobs. Most of the list of symptoms I gave above were also bad for the user (in most situations). Perhaps the worst is that it's addictive, so these symptoms are hard to escape from, and if you do try to quit, withdrawal symptoms make it very hard. Interestingly, there have been no reported incidences of dependence when AASes have been used therapeutically, only when they are used to become more muscly. As far as I know, no one's sure why that is yet.<br />
<br />Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com1tag:blogger.com,1999:blog-3940038590826574007.post-33426223212621991062012-08-17T14:03:00.000-07:002012-08-18T02:41:49.514-07:00Anabolic steroids<div class="separator" style="clear: both; text-align: center;">
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So I've recently started going to the gym, and looking around, there's a fairly standard range of body shapes. Clearly, there's some selection bias, given that people who go to the gym are generally fitter than the average person on the street, but you get the idea.<br />
Then you see people who look like this, who are so far outside the normal range that they can't possibly be achieving those results naturally.<br />
I'm sure that some of them really are doing it through nothing but hard work and a good diet, but steroid abuse exists in a big way, particularly in professional bodybuilding.<br />
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It's important to note first of all that not all steroids have this effect, and not all steroids are illegal - the two main groups are corticosteroids and anabolic steroids. In this post, if I refer to steroids without a prefix, assume it's the latter - I might do another post on cortico's another time.<br />
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These are a group of drugs that work by mimicking natural hormones (testosterone and dihydrotestosterone), although they are synthetic. Their effect is to increase protein synthesis and also to make users more manly (i.e., enlarged vocal cords and testicles, hairier bodies, etc. etc.). <br />
Because they are fat soluble, they are not hampered by cell membranes, which means they don't have to rely on manipulating the receptors on the outside of the cell; in fact, the androgen receptor that the hormone binds to is in the cytoplasm - compared to the quite small, organic structure of the steroid, the receptor is huge, so when the receptor passes through the membrane of the nucleus, the hormone stays bound to it and enters with it. From the nucleus, the receptor-hormone complex can send signals to the rest of the cell or alter how certain genes are expressed.<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
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To understand how they produce the massive increase in muscle, you have to understand how muscle is built in the first place. When exercised, muscles require energy. A lot of this energy can be released through the oxidation of glucose via aerobic respiration, but not all. Some energy comes from the synthesis of ATP through the oxidation of proteins, lipids or other cellular matter. Oxidising the protein in the muscle means that you lose muscle mass, a process called catabolism, which is started by a hormone called cortisol. The ATP is also used in anabolism - the opposite of catabolism - whereby amino acids are reformed into proteins. This way, the overall muscle mass increases.<br />
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Anabolic steroids block catabolic hormones from acting on muscle, so not as much muscle mass is lost in the catabolic stage of exercise. They can also make cells favour differentiating into muscle as opposed to fatty tissue. In addition to those two, they increase protein synthesis. The way they do this is by binding to specific sites on the DNA, which changes the rate of transcription of that particular bit of code. In doing this, they alter the number of certain proteins produced, be they messenger molecules or more muscle.<br />
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I'll do another post explaining about androgenic effects and why they can be dangerous (but also helpful); watch this space!Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-40370625482329713492012-08-17T12:31:00.000-07:002012-10-28T14:39:58.592-07:00AS resultsI suppose I'm a day late with this, but <i>yesterday </i>was a big day for 16-18 year olds across the country - AS and A2 results day!<br />
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Interestingly, this year was the first year since 1991 that the proportion of A* and A grades has decreased. The culprit for this huge rise in top grades is disputed, but generally blamed on one of two things: either we (as children in the UK) are genuinely getting clever, or it's getting easier to As and A*s. The latter of the two (so called "grade inflation") can come across as a bit old-man-ish, almost reminiscent of the three Yorkshiremen sketch, but it does have a point. Is it really possible that teaching standards across the whole country have risen so much that the percentage of people getting the top two grades has increased fourfold in as many decades?<br />
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Earlier in the year, schools across England were called out for choosing exam boards for subjects based on how easy it was to get top grades. Because the boards are all NGOs, they are motivated by profits, and so they want to make themselves more attractive to schools. The danger was that the exams were being dumbed down in order to gain more money for the boards.<br />
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One solution to this is to nationalise all the boards. It's a bit drastic, obviously, and would lead to copious new problems, as all nationalisation does, but if there was no competition between them, then there would be no incentive to making the exams easier. At the same time, if there was only one super-board, there would be no choice about the syllabus, so it would put a lot of power in the government's hands - educating children in a way that benefits a particular party is not unheard of in politics.<br />
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In light of that, I wonder if we're seeing this decrease because the system is under more scrutiny now. Is this the end of grade inflation? A*s have already been added as a "new currency", and Ofqual, the regulator, has issued a warning that the increase in grades does need to be shown to be because of an actual increase in quality of work. At the same time, it's a marginal decrease and it is only one year. This is by no means an established trend.<br />
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Anyway I got AAAA. Woooooo! And at least an A in maths A2, but I might retake some modules to try and push that up to an A* next year.<br />
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<br />Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-41047985570774411042012-08-11T09:49:00.000-07:002012-08-11T09:49:21.135-07:00Medlink pathology project resultsI've just seen the results for the paper I wrote on in vitro meat production and I got a distinction! Woooooo!<br /><br />
For people who actually want to read the paper, I'll put it after the break.<br />
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<span style="font-size: 16.0pt;">Meat
derived from stem cells:</span></h3>
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<span style="font-size: 16.0pt;">Jack
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Abstract</h3>
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The world's meat demand is increasing at
such a rate that farming animals conventionally will not always be possible to
satisfy it. If meat can be made in laboratories or factories on an industrial
scale without the need for the whole animal, many of the problems associated
with its production and consumption will be solved. Currently, economical and technological
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Introduction</h3>
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Problems
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Ethical
concerns about meat are embodied in organisations such as PETA, and revolve
around the treatment of animals<sup>1</sup>. There is evidence that some
livestock, especially pigs, may be more conscious than had been previously
thought. In the <st1:place w:st="on">UK</st1:place>,
many animals are killed unnecessarily inhumanely<sup>2</sup>, and ethical
concerns do not stop at the animals: workers are reported to be mistreated and
underpaid<sup>3</sup>.</div>
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Ecological
worries over rearing and consumption of meat are more complex, but perhaps more
concrete. The world's population is larger than at any point in history, and more
people are consuming more meat.<sup>4</sup> Increased demand for meat results
in more land being used for livestock, with consequent deforestation and
destruction of other habitat.<sup>5</sup> As such, the meat industry is
contributing significantly towards climate change and desertification.<sup>5</sup></div>
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<sup> </sup>Eating
meat is inherently inefficient. Energy from the original food (e.g. wheat) is
lost over the course of the animals' lifetime from their metabolic processes so
we lose much of the original energy stored in the crop grown as animal feed. It
is thought that more vegan diets could hold the key to combating world hunger<sup>7</sup>,
as we could produce significantly more energy from the same amount of land.
This argument is debatable: it implies that the world shares food across
nations and continents. The idea however does have its merits, and the world
cannot afford meat production to continue to rise at its current rate without a
serious revolution of the entire process.<sup><o:p></o:p></sup></div>
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In an age
when we are dealing with world hunger and climate change, meat is a hindrance
on more than one front. Not only are we being energy inefficient, but animals
(particularly cows, pigs and chicken) contribute to the greenhouse effect
themselves through the release of methane and other greenhouse gases.<sup>8 </sup>Some
estimates place livestock as the origin of 50% of the world's greenhouse gas
emissions (including land use, etc.)<sup>8a <o:p></o:p></sup></div>
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All
this is to say nothing of the processing and transportation that the meat
products in our supermarkets go through before being bought and eaten. This
involves fossil-fuels to transport them from farm to factory, to extract the
meat and then to transport the meat to the shops. </div>
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Several
widespread health issues in the world can be attributed to meat, particularly
in the developed world. The most notable and infamous of these is heart
disease. It is thought that the current level of cholesterol intake,
artificially high due to the huge supply of meat, is influential in the high
rate of circulatory disease related deaths (158,084 in the <st1:place w:st="on">UK</st1:place> in 2010 - 32% of all deaths<sup>9</sup>)<sup>10</sup>.
</div>
<div class="MsoNormal">
Meat may
also be linked to cancer<sup>11</sup>, a growing concern especially in the
developed world. In 2010, there were 141,446 deaths from all cancers in the <st1:place w:st="on">UK</st1:place>
(29% of total deaths)<sup>9</sup>. While this figure is for all cancers, and
there are many risk factors for different cancers, it was shown that even after
controlling for other lifestyle risks, such as smoking, eating meat still
increases the incidence of cancer in general.<sup>11</sup> </div>
<div class="MsoNormal">
</div>
<div class="MsoNormal">
It is for
these reasons that there needs to be an alternative to meat. Vegetarian and
vegan diets would be the most cost efficient and effective methods to adapt to
but most people have grown too fond of meat to give it up. In vitro meat offers an alternative,
which could possibly address all these issues. This meat would be grown in
factory-style settings from stem cells.</div>
<div class="MsoNormal">
</div>
<div class="MsoNormal">
Stem cells
can differentiate into many different types of cell thus they are mainly found
in the development stages of organisms. There just one type of cell - the
fertilized zygote - divides, matures and differentiates into a full organism
with many different types of cell. These cells, found in the blastocyst stage
of a mammalian embryo's development, are called embryonic stem cells. Because
they can become any cell in the body, they are known as "pluripotent". They can survive and divide outside the body
in a tissue culture, and are the most flexible type of stem cell.<sup>12</sup></div>
<div class="MsoNormal" style="text-indent: 36.0pt;">
There
is one other type of stem cell found naturally: adult stem cells. These can be
classified into smaller groups, but all are distinct from embryonic stem cells.
Unlike the latter, adult stem cells cannot differentiate into any cell type but
are more prone to develop into one line of cells, for example a blood cell.They
can still differentiate into more than one type of blood cell, but not
something entirely different, for example a neuron.<sup>12</sup> Adult stem
cells are grouped into epithelial,
haematopoietic, and neural. Epithelial stem cells are the most likely to be
useful in the production of in vitro<i>
</i>meat, because the main component of meat is muscle. <sup>13 </sup>Muscle
however, is not the only component of meat, raising issues which will be dealt
with in the discussion section.</div>
<div class="MsoNormal">
<br /></div>
<h3 style="page-break-before: always;">
Discussion</h3>
<div class="MsoNormal">
Health
concerns surrounding the consumption of what is essentially cloned meat were
allayed in April 2010 with a risk assessment by the FDA into animal cloning, in
which they state: "no … hazards were identified that could pose food
consumption risks from ... clones."<sup>14</sup></div>
<div class="MsoNormal" style="mso-prop-change: "Nicki Williams" 20120317T1959; text-indent: 36.0pt;">
The
remaining issues facing in vitro meat production are threefold: practical, economical
and ethical. I address them in that order, as economics must follow the
practicality, and a system needs to have been formulated before it can be judged on moral grounds. <sup><o:p></o:p></sup></div>
<div class="MsoNormal">
<br /></div>
<h3>
<span style="font-size: 12.0pt;">Practical <o:p></o:p></span></h3>
<div class="MsoNormal" style="mso-prop-change: "Nicki Williams" 20120317T2005; text-indent: 36.0pt;">
In
order to look at the difficulties of mass production of stem cell meat, it is
important to first understand the process by which it is made on a small scale.
Muscle has been kept alive ex vivo since 1912, when Alexis Carrel successfully
grew tissues in his lab.<sup>15</sup> Most current work is done in <st1:place w:st="on">Holland</st1:place>, whose government
has provided US $4 million for the venture., 4 times the prize that PETA was
previously offering</div>
<div class="MsoNormal" style="mso-prop-change: "Nicki Williams" 20120317T2005; text-indent: 36.0pt;">
There
are two potential types of stem cells to use: the pluripotent embryonic stem
cells, and satellite cells, specific types of adult stem cell that can fuse
together and mature to form skeletal muscle. <span style="color: windowtext;">Here,
I will focus on the embryonic stem cells because there may be need for more
than one type of cell - meat is composed not just of myocytes, but adipocytes
and blood vessels too. </span></div>
<div class="MsoNormal">
Muscle is
generally formed before birth, where myoblasts, a more specific embryonic stem
cell type, first differentiate into muscle cells, which then fuse together to
form long, multi-nucleated muscle cells.<sup>16</sup> The long myocytes arrange
themselves first to be parallel in a 2-D structure, then in the 3-D shape of
the muscle they will grow into. Thus the simplest way to produce meat from stem
cells would be to use myoblasts. While it is an attractive concept use thigh
myoblasts to produce thigh meat, and wing myoblasts to produce wing meat, in
reality this will not happen. Meat gets its characteristic texture and taste
not from the type of myoblast that makes it, but from use and structure. </div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b>Proliferation &
differentiation:</b> </div>
<div class="MsoNormal">
The texture
of muscle has always been the biggest hindrance in imitation meats, which
heretofore have been largely limited to textured vegetable proteins. Much
texture is due to the fibrous nature of muscle. Muscles can be split up into 5
basic units: protein filaments (grouped together in sarcomeres), myofibrils,
myofibres, and fascicules. The protein filaments are either thick or thin, and
can slide across each other, giving the motor action that is typical of
muscles. The myofibrils are long chains of these filaments, contained within
the cylindrical myofibres, the multi-nucleated cells formed from myoblasts.<sup>17</sup>
Fascicules are bundles of myofibres, and the biggest component of muscle.
Because all of this comes from the progenitor myoblasts, to produce muscle
containing those 5 basic units should be possible with the right culture and
stimulation. This type of stem cell has already been grown in the lab and
considered for production on a large scale (albeit for other purposes). The
first step in the production involves getting as many stem cells from as few
stem cells as possible. This can be achieved by stimulating proliferation,
proved to be possible through the use of leukaemia inhibitory factor (LIF)<sup>18</sup>,
a cytokine. However, as one of the drivers of this proposal is ecological and
to reduce waste, as few chemicals as possible should be used. Alternatives to
sera and stimulants are preferable to than using anything that has to be
manufactured. An alternative to LIF presents itself in the form of the gene
nanog, which is present in pluripotent embryonic stem cells, but only before
differentiation. According to a recent study, this gene is at least partially
responsible for maintaining pluripotency while cells continue to proliferate.
Cells without nanog proliferate, but differentiate at the same time, thus the
number of pluripotent cells decreases.<sup>19</sup> By overexpressing this gene
in stem cells, it is technically possible to produce as many cells as you want,
provided that the stem cells are given the correct nutrients to survive.
Because only one ‘batch’ of cells would need to be genetically modified to do
this, the price could be regarded as a start-up cost. As the procedure is
routinely performed within research studies, it is not cripplingly expensive. </div>
<div class="MsoNormal">
Once they have
proliferated<span style="font-size: 13.5pt; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;"> </span>it is then important
to make myoblasts differentiate into myofibres. It has been shown that this can
be accelerated by stretching and then relaxing the cells; the area of myofibres
increased by 40% over 8 days.<sup>21</sup> With this in mind, the ideal system
for their growth would include a way to stretch the cells as well as providing
them with nutrients and encouraging them to divide.</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b>Nutrition:<o:p></o:p></b></div>
<div class="MsoNormal">
The cells
must also stay alive. Many stem cells can survive in fetal calf serum (FCS),
which is the standard culture. Unfortunately, using this would be contrary to
the original agenda in this particular situation, because FCS requires the
slaughter of pregnant cows. The cows need to be alive to be impregnated, and
reduction in the use of live animals is one of the aims of this research.
Breeding cows only to kill them when they are pregnant would raise new ethical
issues and would not solve the maltreatment of the animals and workers in the
meat industry. Thus, in order for in vitro meat to be successful, an alternative to FCS
would have to be developed. There is already pressure to replace it in cell
culture for these reasons and also because of the risk of contamination if the
foetus contained microbes or pathogens, or if the abattoir was not sterile.<sup>20</sup>
Each type of stem cell requires specific sera to enable proliferation and
differentiation. Media for turkey breast, goldfish, and porcine cells have been
found, but these also contain animal derived substances such as chicken serum. Development
of non-animal related substances that stimulate growth and differentiation while
providing stem cells with necessary nutrients is a prerequisite to the use of in vitro meat as described.<span style="font-size: 13.5pt; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;"><br />
<br />
<o:p></o:p></span></div>
<div class="MsoNormal">
<b>Structure
& texture</b><b><span style="font-size: 13.5pt; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;">:</span></b><span style="font-size: 13.5pt; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;"> </span><o:p></o:p></div>
<div class="MsoNormal">
The tissue culture,
once it begins differentiating, needs a way of organising itself into the 2D
and 3D structure. A scaffold needs to fulfil several criteria: it should be
flexible enough that the muscles can contract (essential to muscle growth,
particularly for the texture of the meat), have a sufficiently large surface
area to promote attachment (muscle cells are require anchorage in order to grow)
and aid diffusion. It should also be able to be separated from the finished
product easily, or alternatively be edible. In vivo, muscles grow according to
the structure they are on and the blood supply to them. It was found that in
order to produce muscle in myofibres and fascicules, the myoblasts needed to be
cultured on something with a stiffness that simulated healthy, non-damaged muscle.<sup>22
</sup>The two main proposals currently are either small edible beads or a porous
sponge, both made from collagen, and the sponge derived from cows<span style="color: windowtext; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;">.<sup>23</sup> </span>As with FCS, the second method is inappropriate if
it cannot be replicated without the use of animals. It is also much more
difficult to retrieve the cells from once they have diffused into the sponge.
Therefore, of these two options, the beads are the better.. Even with the
beads, it would be hard to stretch the cells, particularly on an industrial
scale. One solution suggested is to synthesise spheres of the same size and
porosity, but which expand and contract as a response to environmental factors,
like pH.<sup>25</sup> So far, all in vitro meat research has been geared
towards unstructured meat, useful for mince and patty-based foods such as
burgers or meatballs. The collagen bead structure is useable for anything needing
only muscle cells, but if cultured meat is ever to be considered a real
alternative to meat, there needs to be more variety in the form of more
‘natural’ meat cuts. Examples are chicken breasts, or even a steak. These both
have other types of cells (e.g. adipocytes and blood vessels). The second of
these is worth focusing on; and highlights another hindrance to the production
of meat from stem cells. The importance of blood vessels may seem trivial, but
in fact they serve a very specific purpose in the body during myogenesis and
later throughout the life of the organism and its muscles. The purpose of the
blood itself will be discussed later, but first it is important to understand what
needs to change to the scaffold before it is possible to grow complex meat
structures. Muscle cells need to be within 0.5nm of a nutrient supply in order
to survive, which means that in a 3D structure there needs to be an oxygen
carrier that can diffuse between the cells, or a vascular system. In 2D sheets,
this is not a problem - the whole sheet can be submerged in the medium, and all
cells will be exposed to it. Therefore, without significant advances in the blood
vessel synthesis, in vitro meat will be limited to flat sheets of muscle that
have to be pressed together.<o:p></o:p></div>
<div class="MsoNormal">
Adipocytes (fat cells)
also contribute to the texture. In the patty meat method, it would not matter
where the fat was grown as long as it was grown in the right proportions to
give the meat the desired texture, because all the material is simply pressed
together. Because of this, the fat could be grown in a separate culture, then
added at the end.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b>Blood:</b><o:p></o:p></div>
<div class="MsoNormal" style="text-indent: 36.0pt;">
Blood is important for muscles in several
ways. Firstly, blood supplies muscles with the glucose and oxygen needed for
respiration and takes away the waste products. Tissue culture can supply
nutrition, and waste products can be removed through letting them run off or
diffuse into the air. However, oxygen delivery cannot be performed by the
medium itself. This can either be done through an artificially produced
haemoglobin or by using perfluorochemicals (PFCs). PFCs, while easy to produce,
are not broken down by any known process (the carbon-fluorine bond is very
strong), so remain in the environment as a persistent pollutant, and reports
suggest that they do serious damage to several organs in animals.<sup>24</sup>
With this in mind, artificial haemoglobins (or similar) are the more
appropriate substances to use. These have already been produced from
genetically modified plants and microbes,<sup>23</sup> but no studies have been
done on an industrial scale. <o:p></o:p></div>
<div class="MsoNormal" style="text-indent: 36.0pt;">
The second function of blood vessels in meat
is to provide texture and to encourage the muscles to grow in a particular way.
More advanced types of meat (non-patty based meat) would require vessels, and
that is one reason why it is so difficult to make anything more advanced than a
sheet of muscle. An area of research that could lead to more complex structures
is vasculogenesis, the production of blood vessels without the presence of
other vessels already there. This focuses around angioblasts, another type of
stem cell. Technology for the use of vasculogenesis in tissue culture is not
yet being researched, so this cannot be performed in the short term.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b>Health
issues:<o:p></o:p></b></div>
<div class="MsoNormal">
<span style="font-size: 13.5pt; mso-fareast-font-family: SimSun; mso-fareast-language: ZH-CN;"> </span>Two health
issues that present themselves are the content of the meat and the sterility of
the factories. If the meat is to help combat the health issues related to our
diets, changing what the meat is made of could prove vital. By altering the DNA
of the progenitor cells, meat could be made that contains less omega 6 and more
omega 3 fatty acids. In the western world, the ratio of these two is in favour
of omega 6, rather than omega-3, which we cannot manufacture but improves our
health.<sup>26</sup> <o:p></o:p></div>
<div class="MsoNormal">
The second health issue
is the risk of infection. Factories would need to be kept free from pathogens
in order to keep the meat safe for human consumption. This could be achieved by
using antibiotics, but that could select for super resistant strains, as
happened with MRSA. A better system would be to vet the cells that came in, and
keep them in an argon atmosphere so that any aerobic microbes would be killed. The
muscle would continue to draw its oxygen from the oxygen carrier, not from the
air, so would survive. This suggestion does not account for any pathogens that
live in the culture, so the meat would have to be tested after production as
well. To minimise risks, hygiene in the factories would need to be kept to a
very high standard and any contact with the culture, scaffold and cells kept to
a minimum.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<h3>
<span style="font-size: 12.0pt; mso-bidi-font-size: 13.0pt; mso-fareast-language: ZH-CN;">Economical:<o:p></o:p></span></h3>
<div class="MsoNormal">
From an economical
perspective, the implementation of a scheme like this would require massive
investment. Harvesting the original cells can be done from a simple biopsy, and
bears negligible cost. Genetic modification may be more expensive, but if successful it should be a cost paid very
infrequently. The real expense rests in the medium and the scaffold. Both are
consumed in the process, so need replenishing. As mentioned above, there is not
yet a suitable serum for the growth of the cells, and the scaffold is a very
specific structure that cannot be substituted by anything cheaper Thus it is
incredibly unlikely for meat to be grown in vitro on anything larger than a
laboratory scale in the foreseeable future. Even if both serum and scaffold
were inexpensive and available, a vast start-up cost would be necessary to
build the facilities needed: nothing could be retrofitted for such a particular
purpose.<o:p></o:p></div>
<div class="MsoNormal">
Another issue to
consider is whether consumers would want to eat something cultured in a lab. In
February of this year, 68% of participants in a poll in the Guardian said that
they would eat stem cell meat;<sup>27</sup> it has more opposition than in vivo
meat, but a significant proportion of the public appear to be accepting of it.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<h3>
<span style="font-size: 12.0pt; mso-bidi-font-size: 13.0pt; mso-fareast-language: ZH-CN;">Ethical:<o:p></o:p></span></h3>
<div class="MsoNormal">
Ethically, there are
not many problems with in vitro meat. PETA backs the concept, describing, it as
the morally acceptable alternative to eating meat grown on an animal. The
issues arise from the harvesting of cells and the use of animal sera. In order
to obtain embryonic stem cells, embryos have to be killed. This is questionable
when the embryos are human, but there are fewer objections for animals. Each
animal embryo would be used to feed millions. Harvesting cells from adult
animals would have to be done under anaesthetic and with sterile tools, but is
essentially no different to surgery, so again there is no issue. The one moral
problem is with animal sera, which has been discussed above. Collection of FCS
and other media from animals is often done unethically in abattoirs, which is
one of the problems in vitro meat could tackle, if the cells were less
dependent on substances such as FCS. In order for in vitro meat to be
considered truly ethical, it must use synthetic alternatives to these sera.<o:p></o:p></div>
<h3>
Conclusion</h3>
<div class="MsoNormal">
In vitro
meat from stem cells, while physically possible to produce in the small scale,
cannot be economically scaled up to make a large enough amount of meat for it
to be economically viable. Before that is possible, several advances need to be
made. Firstly, there needs to be an alternative to using animal sera in the
cell culture. Without this, in vitro meat will be both unethical and
impractical. Secondly, a scaffolding material must be created that is porous,
edible, and stretches in response to a stimulus that does not affect the meat.
Thirdly, without a way to create functioning blood vessels, including
circulation of a natural or synthetic blood, in vitro meat will not be able to
progress past 2D sheets of meat that need to be pressed together to create
patty-based meat products. On this basis, in vitro meat is unlikely to be
either an alternative or a supplement to in vivo meat. </div>
<h3 style="page-break-before: always;">
References</h3>
<div class="MsoNormal">
1. The issues, by PETA</div>
<div class="MsoNormal">
http://www.peta.org.uk/issues/</div>
<div class="MsoNormal">
<br /></div>
<h2 style="line-height: 122%; margin-bottom: .0001pt; margin: 0cm;">
<span style="font-size: 12pt; font-weight: normal; line-height: 122%;">2. <st1:place w:st="on">Essex</st1:place>
slaughterhouse exposé finds 'unbearable cruelty and suffering', report by
Animal aid (2010),<o:p></o:p></span></h2>
<h2 style="line-height: 122%; margin-bottom: .0001pt; margin: 0cm;">
<span style="font-size: 12pt; font-weight: normal; line-height: 122%;">http://www.animalaid.org.uk/h/n/NEWS/news_slaughter//2331//<o:p></o:p></span></h2>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
3. Migrant and agency workers mistreated in <st1:country -region="-region" w:st="on">UK</st1:country> meat and
poultry industry, according to Commission report, article by the Daily
Telegraph (2010).</div>
<div class="MsoNormal">
http://www.telegraph.co.uk/finance/newsbysector/retailandconsumer/7432006/Migrant-and-agency-workers-mistreated-in-UK-meat-and-poultry-industry-according-to-Commission-report.html</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
4.Meat Production Continues to Rise, report by the World
Watch Institute.</div>
<div class="MsoNormal">
http://www.worldwatch.org/node/5443</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
5. Livestock's Long Shadow report by the Food and
Agriculture Organisation of the UN (2006), p.66</div>
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http://www.fao.org/docrep/010/a0701e/a0701e00.HTM</div>
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<br /></div>
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7.<span style="color: #666666; font-family: Arial; font-size: 10.0pt;"> </span>L. Baroni et al. "Evaluating the Environmental
Impact of Various Dietary Patterns Combined with Different Food Prodution
Systems," European Journal of Clinical Nutrition, February 2007 </div>
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8. Livestock's long shadow, p. 80</div>
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8a. R. Goodland, J. Anhang (2009), Livestock and Climate
Change: what if the key actors in climate change are… cows, pigs and chickens?
A report by the World Watch Institute</div>
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http://www.worldwatch.org/files/pdf/Livestock%20and%20Climate%20Change.pdf</div>
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9. UK National Office for Statistics (2010), Death
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and <st1:place w:st="on">Wales</st1:place></div>
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10. R. Sinha et al. (2009) Meat Intake and Mortality. In Archives
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11. M Thorogood et al. (1994) Risk of death from cancer and
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13. R.A. Lawrie (2006), Lawrie’s meat science 7th Ed.,
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14. Animal Cloning: A risk assessment by the FDA</div>
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15. A. Carrel, On the Permanent Life of Tissues Outside of
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http://www.aps.uoguelph.ca/~swatland/ch5_0.htm</div>
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20.Serum free media for cell culture, a report by Focus on
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http://www.frame.org.uk/dynamic_files/foa_fcs_free_table_may09.pdf<o:p></o:p></div>
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21. C. A. Powell et al (2002), Mechanical stimulation improves tissue-engineered human skeletal muscle.
In American Journal of Physiology Vol. 283, 5, 1557-1565<b><o:p></o:p></b></div>
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23. <st1:place w:st="on">I.</st1:place>
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24. J. Lee (2003), EPA Orders
companies to examine effects of chemicals. In NY Times, </div>
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http://www.nytimes.com/2003/04/15/science/epa-orders-companies-to-examine-effects-of-chemicals.html</div>
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25. P.D. Edelman et al., In vitro
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26. 2004, Give Livestock the
Omega-3 Gene. In New Scientist, 2433, 18</div>
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<div class="MsoNormal">
27. Guardian.co.uk (2012), Would
you eat lab-grown meat? http://www.guardian.co.uk/commentisfree/poll/2012/feb/20/lab-grown-meat-test-tube-burger?INTCMP=SRCH</div>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-4954132087692352792012-08-05T14:28:00.004-07:002012-08-17T12:39:11.953-07:00Explanation of simple harmonic motion as an example of problem based learning<span style="font-family: Arial, Helvetica, sans-serif;">After exams were over this term, students doing further maths in Abingdon have the opportunity of doing a maths project. Given two weeks, we are asked to find a topic related to maths that interests us, and that we can give a presentation on afterwards. I decided to choose a simple example of a dynamical system, because they are often used to model biological phenomenon. As it happens, the topic I chose wasn't as simple as I thought, but here's how it works, from basic maths upwards:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">(warning: huge post)</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">Simple harmonic motion is easiest to explain by using it as a way of modelling a mass on the end of a spring:</span><br />
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<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-R1gmktxkL6o/UBvinwLy0vI/AAAAAAAAADs/Npwuf2S2pd8/s1600/SHM.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><span style="font-family: Arial, Helvetica, sans-serif;"><img border="0" height="240" src="http://1.bp.blogspot.com/-R1gmktxkL6o/UBvinwLy0vI/AAAAAAAAADs/Npwuf2S2pd8/s320/SHM.png" width="320" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="color: #666666; font-family: Arial, Helvetica, sans-serif;">You'll have to excuse the scribbles.</span></td></tr>
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<span style="font-family: Arial, Helvetica, sans-serif;">when the spring is at rest, there is no force acting on the mass. When the mass is displaced from this position of equilibrium, the spring exerts a force on it in the opposite direction to the direction it moved (in a completely 1D system). This force is directly proportional to the displacement, according to Hooke's law. That is to say:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
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<span style="font-family: Arial, Helvetica, sans-serif;">F = -|k|x</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Where F is the force, x is the displacement and k is some constant that depends on the strength of the spring. k is negative because it is in the opposite direction of x.</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Because there's a force and a mass, and F = ma, there is acceleration (=F/m) towards the point of equilibrium, where x = 0, so F = -|k|x = 0. However, the object still has velocity and mass when it reaches x=0, so therefore it has a momentum (=mass*velocity), so it continues past the point of equilibrium. </span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Therefore x changes direction, so there is a force in the opposite direction to the movement, which makes it accelerate towards x = 0 again. With no energy loss, this continues forever, and is periodic:</span></div>
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<a href="http://2.bp.blogspot.com/-nAmHdHofmPU/UBvpiWtsg8I/AAAAAAAAAD8/bomr4I6tA6U/s1600/SHM2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img border="0" height="246" src="http://2.bp.blogspot.com/-nAmHdHofmPU/UBvpiWtsg8I/AAAAAAAAAD8/bomr4I6tA6U/s400/SHM2.png" width="400" /></span></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">It looks like you should be able to find relationships very easily between x and v, and therefore x and a. It is possible, but not as easy as it looks. </span></div>
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<a href="http://2.bp.blogspot.com/-Z8I1dUHxhLM/UBvrrs-DY3I/AAAAAAAAAEE/NAcHryCD2To/s1600/SHM3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img border="0" height="283" src="http://2.bp.blogspot.com/-Z8I1dUHxhLM/UBvrrs-DY3I/AAAAAAAAAEE/NAcHryCD2To/s320/SHM3.png" width="320" /></span></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Here, I was a bit stuck. This is a second order differential equation: I can't integrate it, so I have to find a general solution, which was something I'd never come across before. So for those people who've never done something like this either, this is how to do it:</span><br />
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<a href="http://1.bp.blogspot.com/--D7B4sYJyms/UBv2BInaEkI/AAAAAAAAAEU/EOs2gbK0Bmo/s1600/SHM4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img alt="My handwriting deteriorates quite badly in this page." border="0" height="640" src="http://1.bp.blogspot.com/--D7B4sYJyms/UBv2BInaEkI/AAAAAAAAAEU/EOs2gbK0Bmo/s640/SHM4.png" title="" width="328" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Because all the 'a' numbers are known constants, it is possible to solve for <span style="background-color: white; font-size: 14px; line-height: 19.200000762939453px;">λ. </span><span style="background-color: white; font-size: 13px; line-height: 19.200000762939453px;">The general solution is then found using y = e^(</span><span style="background-color: white; font-size: 13px; line-height: 19.200000762939453px;">λx), by substituting in the value of </span><span style="background-color: white; font-size: 13px; line-height: 19.200000762939453px;">λ. It is also important to remember the constants, because we are integrating (sort of). Because this is an exponential function, the constants are manifested as coefficients of e. So in our specific example, it looks like this:</span></span><br />
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<a href="http://1.bp.blogspot.com/-DGU-1XxGrCk/UBv4mJwkyEI/AAAAAAAAAEk/NbDiuv9jUdA/s1600/SHM5.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img alt="Bear with me, I don't usually write on tablets." border="0" height="400" src="http://1.bp.blogspot.com/-DGU-1XxGrCk/UBv4mJwkyEI/AAAAAAAAAEk/NbDiuv9jUdA/s400/SHM5.png" title="" width="286" /></span></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">To find <span style="background-color: white; font-size: 14px; line-height: 19.200000762939453px;">λ, we need to find the square root of a negative number. This hadn't been covered in my syllabus before either, but by sixth form most people are aware that the root of -1 is a different type of number, called i. You can read this brief explanation of imaginary numbers if you want, but it isnt really necessary: </span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="background-color: white; font-size: 14px; line-height: 19.200000762939453px;"><br /></span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="background-color: white; font-size: 14px; line-height: 19.200000762939453px;">All numbers I had encountered so far could be represented on a 1-dimensional numberline, like a graph without a y axis. I was also aware that none of the numbers I knew could be multiplied by themselves to produce a negative number. This is because a minus times a minus is always a plus, and a plus times a plus is always a plus, and there was nothing on the numberline apart from minus and plus. </span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14.44444465637207px; line-height: 19.185184478759766px;">However, sometimes it is necessary to take the square root of a negative number. Therefore something apart from either 'minus' or 'plus' has to be created. Because they are not representable on our number line, or by an actual quantity of physical things, these numbers are called imaginary. Imaginary numbers are shown as a y-axis on the numberline. This means that all the numbers I already knew had an imaginary number 'coordinate', but that it was 0. </span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14.44444465637207px; line-height: 19.185184478759766px;">To find the square root of a negative number, first factorise out -1, then take the root of both factors. For example:</span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14.44444465637207px; line-height: 19.185184478759766px;">sqrt(-16) = sqrt[(-1)*(16)] = (i)*(</span></span><span style="background-color: white; font-family: 'Arial Unicode MS', 'Lucida Sans Unicode'; font-size: 13px; line-height: 19.200000762939453px;">±4)</span></div>
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<span style="background-color: white; font-family: 'Arial Unicode MS', 'Lucida Sans Unicode'; font-size: 13px; line-height: 19.200000762939453px;">=</span><span style="background-color: white; font-family: 'Arial Unicode MS', 'Lucida Sans Unicode'; font-size: 13px; line-height: 19.200000762939453px;">±</span><span style="background-color: white; font-family: 'Arial Unicode MS', 'Lucida Sans Unicode'; font-size: 13px; line-height: 19.200000762939453px;">4i</span></div>
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<span style="background-color: white; font-family: 'Arial Unicode MS', 'Lucida Sans Unicode'; font-size: 13px; line-height: 19.200000762939453px;"><br /></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">So, back to finding </span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: 14.44444465637207px; line-height: 19.185184478759766px;">λ:</span><br />
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<a href="http://4.bp.blogspot.com/-CCPgty1xJWE/UBv-o7K_o1I/AAAAAAAAAE0/mp1T7OWJ1kg/s1600/SHM6.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="http://4.bp.blogspot.com/-CCPgty1xJWE/UBv-o7K_o1I/AAAAAAAAAE0/mp1T7OWJ1kg/s640/SHM6.png" width="308" /></a></div>
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Someone else in the class had just done a very impressive explanation of Euler's formula, so I used that without proving it, but an explanation can be seen <a href="http://betterexplained.com/articles/intuitive-understanding-of-eulers-formula/">here</a>.</div>
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<a href="http://2.bp.blogspot.com/-JYHc_IabSvY/UBwHwKNGbcI/AAAAAAAAAFE/kvlCBFjzjuk/s1600/SHM7.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="Still following?" border="0" src="http://2.bp.blogspot.com/-JYHc_IabSvY/UBwHwKNGbcI/AAAAAAAAAFE/kvlCBFjzjuk/s1600/SHM7.png" title="" /></a></div>
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This proves that the displacement is sinusoidal, which means that it is periodic, provided no energy is lost. However, more interestingly, it also means that:</div>
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<span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">v = x' = ωRcos(</span><span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">ωt +</span><span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">α)</span></div>
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<span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">and</span></div>
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<span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">a = x'' = -(</span><span style="background-color: white; font-family: sans-serif; font-size: 13.333333969116211px; line-height: 19.185184478759766px;">ω^2)Rsin(</span><span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">ωt +</span><span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">α)</span></div>
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<br /></div>
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So displacement, velocity and acceleration are all periodic. </div>
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Also, on a side note, substituting x into the equation for acceleration gives:</div>
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<span style="background-color: white; font-family: sans-serif; font-size: 13px; line-height: 19.200000762939453px;">a = -(</span><span style="background-color: white; font-family: sans-serif; font-size: 13.333333969116211px; line-height: 19.185184478759766px;">ω^2)x</span></div>
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Which is quite neat.</div>
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<h3>
Applications</h3>
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SHM is used in very many aspects of very many sciences; here's a few examples from the three main ones we study in school:<br />
<h4>
Physics</h4>
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The mass-on-a-spring can be used as a model for circular motion with one dimension, distance from the starting point. This means that it's very easy to find the acceleration or velocity of the moving object at any one point. Pendulums also follow simple harmonic motion, and any other kind of oscillators too. I don't know, I'm not really interested in physics.</div>
<h4>
Chemistry</h4>
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When two particles are connected together, AS chemists will know that they oscillate (which is what absorbs different frequencies of radiation and therefore gives us IR spectra etc.). The oscillation is basically a mass on a spring. SHM is useful here because you can use it to find the energy of the system:</div>
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<a href="http://3.bp.blogspot.com/--xdG_yhK-8M/UB7kD8iYKKI/AAAAAAAAAFU/muIR5APTEIY/s1600/SHM8.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="http://3.bp.blogspot.com/--xdG_yhK-8M/UB7kD8iYKKI/AAAAAAAAAFU/muIR5APTEIY/s640/SHM8.png" width="317" /></a></div>
Because k and R are both arbitrary constants that you can find out given starting conditions, this shows that the energy of the system is constant. Which is quite exciting.<br />
<h4>
Biology</h4>
We don't really know much about biology, which is one of the reasons I want to have a job in it. Nothing's really changed in non-quantum physics since the 30's, and by and large, we understand a lot of chemistry. With biology, there are so many possible factors to everything that it's very hard to make any kind of mathematical model of a biological system (it is still possible, but currently beyond my skills). Nevertheless, simple harmonic motion has been used as a model of neural oscillations, heartbeats, and the circadian cycle, among others.</div>
Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-51312143429618358952012-07-30T14:33:00.000-07:002012-08-11T09:54:59.569-07:00Blood pressure continued<h2>
Part two: why do we need such high blood pressure?</h2>
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So we have seen how blood pressure can be used as an indicator of largely chronic effects, and that it is a very useful measurement to keep track of. But what about the more acute side of medicine? </div>
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I was lucky enough to stay in cardiothoracic critical care in my local hospital for a while as part of a work experience scheme with a consultant anaesthetist (a very underrated speciality, I have decided). While I was there, I noticed that they were measuring blood pressure on almost every patient. None of the people on the ward was there for chronic problems, so why were they bothering to measure the blood pressure? </div>
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The answer is that they needed to see whether the heart was working properly, as almost everyone there had just been in or was about to go into surgery for a heart operation. If the heart is pumping blood around the body, it will push against the outside of the arterial walls, which is what we call blood pressure. If the pressure decreases, it is likely that the heart is not pumping the blood so well, and the patient might need to be looked at in more detail.</div>
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<br /></div>
<div>
But that is a very crude way of getting a very vague answer. What I wanted to know was what the blood pressure actually signified about the heart that the doctors were interested in. When I asked the consultant this, he answered me with another question: why do we need such high blood pressure? I'll admit, I didn't understand the question when he first asked me it. </div>
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My first thought was that some of the organs need high blood pressure, such as the kidneys: in the nephron, blood needs to be at high pressure in order to undergo ultrafiltration. But there are very few bits of the body that are like that, so it doesn't make sense to have the whole system running under unnecessary stress. What could be the advantage of having high pressure in the system? Does it have an advantage in itself? No. The advantage of running any fluid system at high pressure is to make the fluid move fast. That's what really matters: how quickly can the blood transport the necessary nutrients to the organs, and take away the waste products.</div>
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Again, I thought I'd got it, that we needed to run at such high pressure in order to move the blood around our body fast enough to work properly. Sadly for me, it turns out that the pressure needed to move the blood around our body is much lower than the average blood pressure. All I'd done was work out the question: why do we have such high blood pressure, when the same blood flow could be achieved with much lower pressure?</div>
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<div>
Looking at it from a purely physical standpoint, it makes no sense that two different pressures in the same system can provide the same blood flow. Where is the pressure being lost? There must be some kind of resistance that we are artificially providing in order to keep flow lower than its maximum. The pressure could be coming from the organs, or the arteries. We already know that only a few organs need the maximum pressure, so it must be coming from the arteries before the blood reaches the tissue it's going to. That can easily be provided by the muscle layer in the vessels, but I still hadn't worked out<i> why</i> it happened, just<i> how</i> it happened.</div>
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<div>
Why would the body have adapted to provide more resistance in the vascular system, making more work for the heart? Because it's not a fixed system: the muscles in the arteries can relax, reducing the pressure for various tissues, increasing the flow to those organs. This means when any tissue needs to increase the rate it gets its nutrients, the resistance of the vessels supplying that tissue can drop, which makes the flow spike immediately.<br />
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So to answer the question, we need high blood pressure so that blood flow to any part of the body can be increased straight away. That doesn't really explain why they measure blood pressure. That'll be in part three.</div>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-4707315005866454292012-07-30T14:32:00.001-07:002012-08-11T09:52:24.304-07:00Blood pressure<h2>
Part one: problems with extreme blood pressures</h2>
As a culture, one of the facets of medicine we're obsessed with is blood pressure. This makes sense: hypertension in particular is a big problem in the obese western world, and hypotension can be equally as serious. It's also very easy to measure, using the fantastically named sphygmomanometer, or blood pressure cuff, of which every GP has at least one.<br />
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<h3>
Hypertension (high blood pressure)</h3>
<div>
Blood pressure is defined as how hard the blood is pushing against the arteries as it is moved around the body. Arteries have adapted to compensate for being pushed against by developing a layer of elastic tissue, so they can stretch with different pressures. Unfortunately, these elastic layers are not adapted to deal with very high blood pressure, when they are being stretched constantly. Like an elastic band, if you stretch an artery too much and too often, it stops becoming elastic. In the case of arteries, they harden (ateriosclerosis, not to be confused with but similar to atherosclerosis, which is also to do with cholesterol and a build up of fatty substances). Because the arteries harden, the pressure of the blood continues to be high until it reaches the arterioles, which are not developed for that pressure at all, so they burst.<br />
This is a problem particularly in organs like the brain, where a burst blood vessel increases the pressure of the whole cranium hugely, and can leave permanent damage.<br />
Hypertension also leads to heart failure, because the coronary arteries harden, so when more blood to the heart is needed (e.g. running for the bus), they cannot expand to allow that amount of flow, so the heart doesn't get enough glucose or oxygen, so parts of it die; which is a heart attack. Obviously that's a problem. The other way high blood pressure leads to a heart attack is that the left ventricle has to work harder to pump the blood around the body at a higher pressure, so the muscle thickens (hypertrophy). Because the muscle is thicker, it requires more oxygen and gluscose, so the same thing happens as when above.<br />
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The reason this is important in the western world is because we are increasingly ticking more and more risk factor boxes: the population is aging, becoming fatter, drinking and smoking. It can also be unsymptomatic for a long time before a huge event happens, so it is important to measure even apparently healthy people.<br />
<h3>
Hypotension (low blood pressure)</h3>
</div>
<div>
In some people, who exercise a lot, low pressure is a sign of good health and fitness. It can also be caused temporarily by alcohol, other drugs, or a postural change, among others. Mostly, it is harmless.</div>
<div>
However, in acute and extreme circumstances, where hypotension is caused by blood loss or heart failure, it becomes very harmful. The brain (as well as other organs) doesn't get enough blood, which contains the glucose and oxygen it needs to survive, so it begins to die. This is a state called shock, which can be life-threatening. The loss of volume of blood is not always as obvious as a bleed; dehydration by diarrhoea or insufficient fluid intake can also cause hypotension, but this is likely to be less serious.</div>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-21014629565401552762012-04-29T11:24:00.001-07:002012-04-29T11:25:23.380-07:00<div class="separator" style="clear: both; text-align: center;">
<a href="http://s0.geograph.org.uk/photos/70/18/701809_a2ec3225.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="240" src="http://s0.geograph.org.uk/photos/70/18/701809_a2ec3225.jpg" width="320" /></a></div>
<h2>
<span style="font-family: Arial, Helvetica, sans-serif;">GP Work Experience</span></h2>
<div>
<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">This is Wallingford Medical practice. It's a building on the side of a small stream in a town just a few miles from a train station which is two stops from my station. To the right of the picture, there's a community hospital, including a maternity ward. My week's work experience was spent mainly in the consultation rooms, but I did get to see the hospital too; thanks to everyone's hospitality, I managed to see pretty much everything.</span></div>
<div>
<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Work starts early in GP practices; I knew that already in theory, but the reality is coffee and morning discipline. Which I actually enjoyed - getting up to do something you are really looking forward to is a great feeling.</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">One difference between salary doctors and partners is that partners have to work the hours to finish the work, and salary doctors only have to work the hours they're paid. I was shadowing a partner, so I was in bright and early, and was allowed to sit in on the practice meeting. Practice meetings are great at showing the business side of the general practice, something that is not so prevalent in other areas of the NHS, and it gave me an insight into how everyone worked as a team, despite spending most of their days shut off from each other in their rooms. The other thing I gleaned from the meetings was that no matter how many years you've been a doctor, there's always more to learn. In the practice meeting, two doctors were asking for study leave to go on different courses to learn about more in fields they're interested in, and in another meeting, a consultant physiotherapist came and talked about what she did and how GPs can help (when to refer, what to expect etc.).</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Each day is split into morning surgery, then coffee, then visits, then lunch (meetings and paperwork), then afternoon surgery. There is also ward rounds of the hospital (which I got to shadow on the last day) in the morning, to check up on patients in the wards and reissue any drugs that needed a new prescription for.</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">It's hard to pick a favourite part of GP work, because each patient is so different that it's difficult to generalise. I'll probably post one or two of the cases I thought were the most interesting as individual blog posts, but the thing I noticed the most, in visits and in consultations, and in the hospital, was how much the atmosphere was moulded around the patient. Every person was different - an excited visit from an expecting young mum, a calm talk about testicles with a nervous teenage boy, a veeeerryy sloowww conversation with a depressed woman - I could go on. </span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">The relationship with the doctor is also different each time, and that's one of the challenges of general practice, I think, because you don't only have to have gone through umpteen years of medical training and have the responsibility of looking after all of your patients, but also you have to be able to communicate with whoever walks through that door. Communication is different to making friends with, as well. In a lot of cases, it would be easy to let the patient tell you what they think is wrong with them and exactly what drugs they want, write a prescription, and let them go. But often, that's not what's needed, and it can be hard to tell someone that they need nothing at all, or a different treatment, or tests. Cooperation is important, and the needs of the patient come first, but a confident, misinformed person could be more of a danger to themselves than the disease they have.</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">I'll post more about GP work later, but this post is long enough. Bite sized work experience!</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;"><br /></span></div>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-77961807164391798382012-04-11T08:11:00.000-07:002012-04-11T08:11:50.583-07:00WOOO!Finally finished my 2011 in science series. That took a LOT longer than expected. But now that means I am free to post whatever I want!<br />
I have just finished a week's work experience in a GP surgery, which was fantastic, so I'm sure the next few posts will be devoted to that. Also making an Easter resolution to add pictures to my blags so they look less boring.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-55773941970035539902012-04-11T08:09:00.001-07:002012-04-11T08:09:54.571-07:00December: Microbots and MutantsOkay, so the title is a bit of a lie. Again. But scientists <i>did</i> manage to grow eyes on the side of tadpoles' heads. Which pretty much makes them mutants. Why did they do this to the poor baby frogs? Well, it revealed an entirely new form of control over the formation of organs in the body. By altering voltage gradients, they were able to produce eyes in parts of the body that would never normally have eyes. While this may not have any clinical applications, it is an interesting find in the world of embryology.<br />
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Nanorobots were also new to the world in December. These are small (<1mm) machines that can be steered using magnets to the right place in the giant 3D maze of the circulatory system to detect disease and deliver the drugs needed. They have been in the pipeline since 2007, but development started in December last year.<br />
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In other science: 2 earth size exoplanets and 1 hospitable exoplanet in the Kepler system (Kepler-20e, 20f, and 22b respectively); engineers at MIT make a camera with 1 trillion frames per second, fast enough to capture light travelling across surfaces, and a potential vaccine for HIV goes into production.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-61805370425576505622012-04-11T07:38:00.000-07:002012-04-11T07:38:05.213-07:00November: elderly embryos and eroticaThis month in stem cell news: induced pluripotent cells were created from people as old as 101, a feat which was previously thought impossible due to the ageing process of living organisms. The elderly stand to gain the most from therapies involving stem cells, so the news that they might be able to culture their own could open up new doors in regenerative medicine. Or it could confuse us even more about ageing. Stem cells were also coaxed into specialising into the dopamine producing cells that are damaged in Parkinson's disease early in the month.<br />
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On the slightly less serious side of medicine, a woman masturbated in an MRI scanner. Kayt Sukel stimulated herself to orgasm while held still in the device so that her brain activity could be monitored. It's hoped that the data might help both men and women who have problems climaxing, and also that it might offer an insight into how we feel happy.<br />
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In other science: a one molecule "car" is built; Scottish engineers start to sell their bionic legs, and the six men put into isolation 520 days previously to simulate a trip to Mars are released.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-47931463196031458872012-02-22T14:16:00.000-08:002012-02-22T14:16:47.415-08:00October: Millions of people, malaria, and maybe cloning?October 18th was a bad day for Malaria, which means it was a great day for the rest of the world. On the same day that WHO announced a worldwide drop by 20% of deaths from malaria, signalling the downfall of one of the world's biggest killers, a malaria vaccine was reported to be successful. In the trial, including 15,000 children, the participants had about half the risk of getting the disease as those without the vaccine. Malaria kills 655,000 people per year, and the work towards eradicating it is a long and arduous task, so good news such as this is always welcome. By the time I will (hopefully) be training to be a medic, it is estimated that another 8-10 countries will have rid themselves of it; hopefully it will follow the same path as polio - a disease which had had no new cases in India, one of the previous hotspots, for 9 months by October 2011.<br />
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Stem cells again featured in the headlines for October, this time for their production. Dolly the sheep made somatic cell nuclear transfer famous when she was the first mammal to be cloned in the late 90's; this method had been used since then to try and clone humans so that embryonic stem cells might be made without actual fertilisation of an egg by a sperm cell. However, the embryos produced in this method, which involves taking the nucleus out of an egg and inserting the genetic material of an adult cell (not a sex cell) in order to gain a genetically identical replica of the original adult, did not divide further than 6-12 cells. In order to bypass this method, a team in New York tried a new method: the genetic material of the adult would still be inserted, but this time without first enucleating the egg. This allowed the cell to develop into a blastocyst, where the embryonic stem cells are formed. However, because there was the nucleus of both the adult cell (containing 2 'sets' of chromosomes) and the nucleus of the egg (containing 1 'set' of chromosomes), there was then three of each chromosome. Which, sadly, means that the technique is not quite ready for use in medicine, as it doesn't yet produce cells with only the genes of the donor, and there may be problems with the chromosome numbers. Definitely a technique to watch in the future, as the use of stem cells edges closer towards the mainstream.<br />
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In other science: 7 billion people are living on the planet, according to the UN, the dwarf planet Eris is apparently just as big as Pluto, and a study suggests that exercise is just as good as drugs at preventing migranes.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-70269712737358485322012-01-13T10:31:00.000-08:002012-01-22T10:32:16.381-08:00September: Harvesting Stem Cells and Hydrogen CarsI've been writing a lot about the new and exciting capabilities of stem cells, but without a big enough supply of them, there is no hope that any of the treatments will ever be applied. When left to their own devices on a plastic culture dish, they do reproduce, but rather than into the useful pluripotent stem cells, they create other body cells, which cannot be used in therapies. So when, in September, a new type of plastic was devised that allowed stem cells to grow and still keep their characteristics, it got us one step closer to the clinical use of these new treatments.<br />
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Following on from August's discovery of an enzyme that produces hydrogen from water, the start of the new school year also was the start of MEC technology, or Microbial Electrolysis Cells. Osmotic power stations already capitalise on the potential difference between salt- and freshwater, but these new cells also add a bacteria that produces hydrogen gas to create a self sustaining, relatively cheap method of producing hydrogen for use in cars and other technologies.<br />
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In other science: a detector is released that can tell when we're lying, blood vessels are printed on a 3D printer, and a single molecule motor is engineered.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-82978318817009843452012-01-12T09:30:00.000-08:002012-01-22T09:31:23.580-08:00August: Spermatogenesis and Skin That Stops BulletsOther than the two titular breakthroughs, late in the summer of last year, a new method of fighting cancer was being pioneered: the use of a modified smallpox virus to target cancer. The main problem with using biological agents to combat tumours is that they are destructive and can harm the healthy cells as well as the cancerous ones. However, a team has managed to change the vaccinia virus, which gets its name from being the virus used as a virus against smallpox, to only replicate in the presence of a chemical pathway found in cancer. Seven out of the eight patients on the highest dose were found to have it reproducing in their tumour only. While it is a long way from 'curing' cancer, this could be used as a carrier to deliver drugs to the affected areas in the future.<br />
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A Dutch artist used silk from engineered silkworms to create semi-bulletproof skin. By weaving the silk between the layers of human skin cells, she created a membrane that was able to withstand a .22 bullet fired at reduced speeds without breaking. The round still went 2 inches into the gel model she was using, but there is some hope that the technology could be used to create 'bioarmour' eventually.<br />
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In Japan, mice stem cells were manipulated into primordial germ cells, which can produce sperm. The sperm was normal looking and even fertilised female mice to produce healthy offspring. The aim of this project was to help infertile men, and could have very real and useful implications in today's world.<br />
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In other science: near death experiences are explained away as symptoms of oxygen starvation, it is speculated that nucleotides may have come from meteorites, where they are often found, the dark side of the moon's rough surface may be due to a collision with a second moon, and hydrogen is made from water using an enzyme.<br />
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<br />Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-91657327733838050232012-01-11T07:41:00.000-08:002012-01-22T10:34:38.142-08:00July: An Artificial Organ and AutismThe midpoint of the year heralded the first successful human transplant of artificial tissue. The 36 year old patient was given a porous trachea soaked in his own stem cells to treat an inoperable tumour the size of a golf ball. To create an identical copy of the man's windpipe, 3D imaging software was used to create a virtual version that was transferred into a real product in Sweden.<br />
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It was also shown in July that brothers and sisters of people with autism show very similar brain activity in certain situations, notably where they are looking at people's faces. This part of the brain shows decreased activity both in people with Asperger's syndrome and also in their siblings. As the search for a possible genetic cause for autism continues, this could be used as a 'biomarker' for familial risks of the syndrome.<br />
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In other science: a trial investigating the use of stem cells to help MS patients, the earliest bird known (150 million years before Archaeopteryx) was found, and another moon of Pluto was discovered.Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-10515045294840099912012-01-10T14:27:00.000-08:002012-01-22T10:33:39.206-08:00June: Breakthroughs in Bacteria<span style="font-family: Arial, Helvetica, sans-serif;">Chances are, if you're reading this, you'll know about DNA, and the 4 bases that are used to make it in very nearly every organism on earth ever: adenine, cytosine, guanine, and thymine. So you'll understand what it means when I say that in June 2011 a group of scientists managed to evolve a culture of E.Coli that <i>doesn't use thymine.</i> Or even Uracil. What does this mean in terms of medical progress? To be quite honest, I'm not sure. I suppose it shows the extent to which we can play around with the molecules of living things, which will be integral to medicine in the next century, in my humble opinion. Also in genetics that month, research was published that demonstrated the use of enzymes packaged in virus shells to "repair" the DNA in the liver of haemophilic mice, which reduced the effects. Slightly. Well, watch this space.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">Evolution had its fair share of the limelight for a second month running, with yeast having been shown to evolve to a multi-cellular organism in the lab in about 350 generations, selecting for organisms that clumped together using a centrifuge. After 60 days, one of the cultures was forming structures where all the cells were joined together, with the same DNA, working together. These findings shed light on the mysterious leap from single celled organisms to multi-cellular life forms.</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">In other science: the world's first biological fuel cell is made, 2 elements join the periodic table, worms are found to live in near-anaerobic conditions, type 2 diabetes was reversed in 7 out of 11 patients on a 600 calorie per day diet for 8 weeks, and the war on anti-bitoic resistant bacteria advances.</span></div>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-74789721189325673282012-01-08T07:06:00.000-08:002012-01-08T07:07:32.835-08:00May: Setbacks and the Space Shuttle<span style="font-family: Arial, Helvetica, sans-serif;">Stem cells may have been racing ahead into the futuristic world of 'self-transplants' over the first quarter of last year, but all was not as peachy as we had hoped: in an experiment researching this process on mice, many of the new cells were rejected. It is thought that this was due to the way they "became" stem cells (the cells were originally skin cells before being subjected to an engineered virus that changed them into pluripotent stem cells in a procedure first done in 2006). Sadly, the new research casts doubt on the viability of the use of stem cells in transplants, despite human neurons being made for the first time from induced pluripotent stem cells.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">May was also a big month for palaeontology, with two main discoveries: the first ever evidence of biomineralisation (using mineral substances to form biological structures like shells, bones, hair and teeth), and the revelation that the sense of smell in mammals was what led to the increased development of our brains. </span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">In other science: being overweight was found to make you 71% more likely to develop dementia, a material that uses titanium dioxide and sunlight to break down any organic pollutants on it and in the air around it, the space shuttle launches for the last time, and a paralysed man learns to walk again after electric impulses are applied to his spinal cord.</span>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0tag:blogger.com,1999:blog-3940038590826574007.post-28648734447950560242012-01-07T03:30:00.000-08:002012-01-08T07:08:27.292-08:00April: Bumble Bees and Bloody Big Lasers<span style="font-family: Arial, Helvetica, sans-serif;">Stem Cells hit the news again in April as the first human heart was constructed using them. The Minnesota-based team created the organ using donated hearts that were stripped down to the collagen "scaffolding", then injected with stem cells, which specialised into heart cells in response to the structure they were injected into. While this technology is very far away from being able to be used in a clinical setting, this might open some doorways into stem cell transplants. </span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Meanwhile in Japan, scientists have given mouse stem cells a specific combination of nutrients that has stimulated them into maturing into a functional retina: something to lookout for in the future for treatment of blind people.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">The early Spring months also brought us news that mobile phones may be killing bumble bees, insects on which many crops and flowering plants lean on to survive. The research caused controversy in the bee-studying world, however, and many are skeptical about it, saying that there needs to be more research into air pollution and agriculture's effects on the creatures. There was no doubt about the need for research, though: the UN has already said that humans need to change their behavior in order to help bees survive, as we are so dependent on them.<br /><br />In other science: the Extreme Light Infrastructure gets given the go-ahead by the European Commission. This is a collection of 3 lasers, each designed to emit pulses of greater power than has ever been used by human civilisation in order to try and break down vacuum itself. </span>Jackhttp://www.blogger.com/profile/06127986159957010823noreply@blogger.com0