1
Just Chat! / Re: what is "money"?
« on: 23/06/2018 10:28:41 »
Can someone translate the above into a language I can understand?
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2
General Science / Re: What are the leading technological and social challenges that need addressing?
« on: 22/06/2018 14:54:08 »
Maybe your innovation could be a system to help people to remember to follow the forum rules and please phrase post titles as questions...?
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3
Physiology & Medicine / Re: Can you become vitamin D deficient during summer?
« on: 17/06/2018 12:30:28 »Can you become vitamin D deficient during summer?
Yes, if you don't go out in the sunshine and you don't eat a diet with either natural or supplemental vitamin D. Believe it or not, there are plenty of people in the situation in many countries right now, especially the UK.
In fact, most people in high northern latitudes (UK, especially Scotland) become very low in vitamin D by the end of winter, meaning that the begin the summer with a functional vitamin D deficiency. If they don't catch up and "make hay while the sun shines", or rather make vitamin D, then they will enter the next winter in an already low vitamin D state, meaning that they become even more deficient. Over time this results in bone problems like osteomalacia, which is prevalent in dark skinned people and especially those also wont to cover every square centimetre of skin for "cultural reasons"...
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4
Physiology & Medicine / Re: How are transcatheter aortic valve replacement - TAVR - procedures carried out?
« on: 11/06/2018 07:59:21 »
When you feel better and able, do please tell us about the procedure, what happened and what it was like. It would be really interesting to hear about it and how they do the procedure.
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6
Physics, Astronomy & Cosmology / Re: Do you become an owner of a star or a planet if you get there first?
« on: 03/06/2018 09:18:10 »You are basing this proposal on an equivalent principle: stellar nullis (pardon my Latin).
You missed out an "i" in "nullius"! It would also be "stella nullius", @evan_au, or "sidus nullius", sidus being the other word for star. [My Latin's not that great either, but I did enough to get me a GCSE and I think it made me better at English in the long run, so I don't regret doing it!]
There are 200 billions stars in our galaxy. More then enough for everybody.
That seems like a lot, doesn't it? But when you think that there are 7.5 billion on Earth now, scheduled to reach 9-10 billion by mid-Century, that's not very many years of stars, in the grand scheme of things, before we've run out of stars to give to new humans.
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7
General Science / Re: The sounds of science...
« on: 02/06/2018 10:33:25 »
Great idea for a thread - well done for starting it!
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8
Geology, Palaeontology & Archaeology / Re: Is this fools gold or real gold?
« on: 19/05/2018 21:12:20 »
I'll bet my mortgage that that's pyrites (fool's gold)...
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9
Physiology & Medicine / Re: Does an under-active thyroid affect blood circulation?
« on: 19/05/2018 20:42:20 »
Yes, hypothyroidism does affect the heart and blood vessels.
Thyroxine, the hormone produce by the thyroid, increases heart rate and also makes the heart pump harder (increased ventricular contractility). It also reduces the systemic vascular resistance acting on the arteriolar smooth muscle cells.
At the same time, elsewhere in the body, thyroxine increases the volume of circulating blood by promoting release of the hormone erythropoietin, which increases red blood cell mass; in the kidney, the renin-angiotensin system is activated which increases sodium reabsorption - this increases circulating volume. In the vasculature, throxine promotes synthesis of nitric oxide, a hormone that relaxes blood vessels.
Thyroxine deficiency results in the reverse of all of these effects; sufferers may have bradycardia (low heart rate) and heart failure and poor peripheral perfusion. Chronic hypothyroidism can also lead to raised cholesterol levels.
Fortunately these problems can be readily reversed with simple thyroxine supplementation, which is titrated to the correct dose clinically and biochemically. But do you know for certain you have this problem?
Thyroxine, the hormone produce by the thyroid, increases heart rate and also makes the heart pump harder (increased ventricular contractility). It also reduces the systemic vascular resistance acting on the arteriolar smooth muscle cells.
At the same time, elsewhere in the body, thyroxine increases the volume of circulating blood by promoting release of the hormone erythropoietin, which increases red blood cell mass; in the kidney, the renin-angiotensin system is activated which increases sodium reabsorption - this increases circulating volume. In the vasculature, throxine promotes synthesis of nitric oxide, a hormone that relaxes blood vessels.
Thyroxine deficiency results in the reverse of all of these effects; sufferers may have bradycardia (low heart rate) and heart failure and poor peripheral perfusion. Chronic hypothyroidism can also lead to raised cholesterol levels.
Fortunately these problems can be readily reversed with simple thyroxine supplementation, which is titrated to the correct dose clinically and biochemically. But do you know for certain you have this problem?
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10
Technology / Re: What determines when a steel spring develops metal fatigue?
« on: 13/05/2018 23:10:41 »
This article on the mechanism of metal fatigue might help to get the ball rolling.
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11
Chemistry / Re: What can nanobots do?
« on: 22/04/2018 10:13:49 »
We just published this article about controlling nanorobots to move cargoes around inside cells.
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12
Cells, Microbes & Viruses / Re: Where did the first virus come from?
« on: 20/04/2018 15:57:43 »
Somehow I missed this post the first time, so here I am, a decade later, answering the question! I hope @neilep you're not too frustrated by the wait. But look on the bright side, people have spent longer on hold on the phone trying to cancel their direct debit with Eon, HMRC or BT...
Viruses are obligate intracellular parasites. In plain English, they are infectious packets of genes that require a living cell to provide key functions that they lack so that they can replicate and increase their numbers.
Viruses come in many different shapes and sizes, both literally, and metaphorically. Some are absolutely tiny: particles of norovirus, which is one of the commonest causes of diarrhoea and vomiting, are just 30nm - 1/30,000th of a millimetre - across. Other viruses are enormous in comparison. The recently-discovered mamaviruses, pithoviruses and pandoraviruses are so large that there were initially mistaken for bacteria, which are usually orders of magnitude bigger than a virus.
This broad diversity, and the fact that viruses target every living entity on Earth including even other viruses (there are viruses that prey on viruses: these are called virophages), suggests that they have been around for a very long time and may even predate modern multicellular life itself.
One theory of the origin of viruses posits that they were initially a spin-off from the first cells. Genetic functions that had evolved to replicate themselves escaped the confines of their parent cell and became independent entities that nevertheless came home to roost in the cell to replicate but otherwise had little else in common.
Other hypotheses even regard some viruses as the origin of life on Earth. The giant viruses mentioned above (gyruses) contain such a broad repertoire of genes that cross all three of the main kingdoms of life, and also even include genes not seen in any living species, suggests that perhaps these entities gave rise to us all from the primordial soup.
The bottom line is that viruses contain an assemblage of genes that enable them to freeload off living cells, which they hijack by first fooling the cell into allowing them in, and then assimilating by using genetic tricks that can deactivate all but the most essential and useful cellular systems to enable the virus to grow rapidly, or they do the opposite and deactivate themselves so that they can lurk undetected within the genetic recesses of the cell, either by pretending to be a miniature chromosome that the cell ignores, or inserting themselves inside the host cell's own DNA. In both cases they end up immunologically "off grid".
But, next time you are sneezing into a hanky having fallen prey to another rhinovirus infection, you can take some solace from the fact that this is not a modern problem. Genetic analysis confirms that dinosaurs had herpes! More a case of T-sex than T-rex, perhaps...
Viruses are obligate intracellular parasites. In plain English, they are infectious packets of genes that require a living cell to provide key functions that they lack so that they can replicate and increase their numbers.
Viruses come in many different shapes and sizes, both literally, and metaphorically. Some are absolutely tiny: particles of norovirus, which is one of the commonest causes of diarrhoea and vomiting, are just 30nm - 1/30,000th of a millimetre - across. Other viruses are enormous in comparison. The recently-discovered mamaviruses, pithoviruses and pandoraviruses are so large that there were initially mistaken for bacteria, which are usually orders of magnitude bigger than a virus.
This broad diversity, and the fact that viruses target every living entity on Earth including even other viruses (there are viruses that prey on viruses: these are called virophages), suggests that they have been around for a very long time and may even predate modern multicellular life itself.
One theory of the origin of viruses posits that they were initially a spin-off from the first cells. Genetic functions that had evolved to replicate themselves escaped the confines of their parent cell and became independent entities that nevertheless came home to roost in the cell to replicate but otherwise had little else in common.
Other hypotheses even regard some viruses as the origin of life on Earth. The giant viruses mentioned above (gyruses) contain such a broad repertoire of genes that cross all three of the main kingdoms of life, and also even include genes not seen in any living species, suggests that perhaps these entities gave rise to us all from the primordial soup.
The bottom line is that viruses contain an assemblage of genes that enable them to freeload off living cells, which they hijack by first fooling the cell into allowing them in, and then assimilating by using genetic tricks that can deactivate all but the most essential and useful cellular systems to enable the virus to grow rapidly, or they do the opposite and deactivate themselves so that they can lurk undetected within the genetic recesses of the cell, either by pretending to be a miniature chromosome that the cell ignores, or inserting themselves inside the host cell's own DNA. In both cases they end up immunologically "off grid".
But, next time you are sneezing into a hanky having fallen prey to another rhinovirus infection, you can take some solace from the fact that this is not a modern problem. Genetic analysis confirms that dinosaurs had herpes! More a case of T-sex than T-rex, perhaps...
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13
Physiology & Medicine / Re: Is it dangerous to stop hypertension medication?
« on: 15/04/2018 11:07:13 »
He doesn't say what he's smoking...
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14
Cells, Microbes & Viruses / Re: How many cells do bacteria contain?
« on: 01/04/2018 09:16:49 »There is a popular theory that some interior structures of the bacterial cell were once separate organisms which came to live within the bacterial cell in a symbiotic relationship.
- The case is strongest for mitochondria and chloroplasts, which have their own DNA
- It's not quite so clear for other organelles like ribosomes, which have no DNA, but do contain structural RNA
See: https://en.wikipedia.org/wiki/Bacteria#Cellular_structure
https://en.wikipedia.org/wiki/Ribosome#Origin
Evan, I think you are getting confused by the endosymbiont theory that accounts for the organelles, like mitochondria, in some eukaryotes.
While it is true that the elements that operate inside a bacterial cell may have once been separate processes that were brought together to make a bacterium as a single-celled entity, complex structures like mitochondria are thought to be ancient bacteria themselves that sought refuge inside a eukaryotic cell with one providing a function for the other.
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15
Physics, Astronomy & Cosmology / Re: Are distant galaxies receding owing only to space expansion?
« on: 23/03/2018 21:35:35 »
No; while the intervening space is growing more extensive - meaning that galaxies are retreating from us, those galaxies have their own motion too, which is superimposed upon the expansion of the Universe. In some cases the movement of the galaxies takes them away from us, but in other cases they may be moving towards us. A good example is Andromeda, which is racing towards us on a collision course that will impact in 4 billion years' time. The space between us and Andromeda will, nevertheless, have expanded in that time.
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16
Cells, Microbes & Viruses / Re: Could a virus or bacterium survive inside a rock?
« on: 23/03/2018 10:24:53 »But the Desulforudis bacterium was found in a deep gold mine
Pursuant to Evan's post, this is me down a gold mine in South Africa looking for long-lost microbial life!
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Cells, Microbes & Viruses / Re: Could a virus or bacterium survive inside a rock?
« on: 23/03/2018 10:22:32 »
This is a really nice interview about extreme bacteria surviving in the Atacama desert and the prospects for life on Mars. It's pertinent to this discussion.
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18
Chemistry / Re: Chlorine / Chloride
« on: 19/03/2018 17:52:20 »
@vivian maxine - can you please follow the forum policy and format your thread titles are questions in future?
Also, can you please alter the title of this thread accordingly. (Action menu drop-down and click "modify" to do this).
Thanks
Also, can you please alter the title of this thread accordingly. (Action menu drop-down and click "modify" to do this).
Thanks
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19
Physiology & Medicine / Re: What can you tell me about p3 deletion?
« on: 16/03/2018 18:38:23 »
Yes, I don't think it's called "petrie"; I think you may have misheard that; the syndrome in question is "3p deletion" - it's where a segment of the short "p" arm of chromosome 3 has been lost from some or all of the cells in the body. If the loss is inherited from the sperm or egg that made the individual then every cell will carry the change and the syndrome is likely to be more severe. If the deletion occurs within one of the stem cells forming the developing embryo then there is the potential for fewer of the body's cells to be affected and the syndrome may be less severe. Equally, the scale of the deletion may vary between individuals; if fewer genes are affected, the presentation may be less severe than if more genes have been lost.
Broadly, 3p deletion can present with intellectual and social disabilities (like autism), growth restraint and muscle problems. Because these are genetic problems, then unfortunately, there is no prospect, at the moment at least, for a patient to be cured I'm sorry to say...
Broadly, 3p deletion can present with intellectual and social disabilities (like autism), growth restraint and muscle problems. Because these are genetic problems, then unfortunately, there is no prospect, at the moment at least, for a patient to be cured I'm sorry to say...
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Physiology & Medicine / Re: What would happen if you stabbed yourself through your upper trunk?
« on: 13/03/2018 20:13:44 »
Probably a combination of a lack of anatomical knowledge coupled with an aversion to sticking things into oneself deters most people from trying to kill themselves this way. People aiming to commit suicide "like" the idea of dying (more than they like the idea of being alive) but that doesn't mean that they like the process. As a result, approaches that are very fast with little margin for error or reversing the process tend to be preferred: jumping from a height, medications, hanging and so on.
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