David Bradley – Page 300

Workout limits

Do you workout hard? Is “no pain, no gain” your exercise ethos? Do you feel like you are not getting the fitness results you expect? Your brain could be to blame.

Yagesh Bhambhani and Rohit Malik of the Faculty of Rehabilitation Medicine, at the University of Alberta, Edmonton, Canada and Swapan Mookerjee of Bloomsburg University, Bloomsburg, Pennsylvania, USA, have monitored the oxygen levels of blood flowing in the brains of healthy volunteers while they worked out using near infrared spectroscopy.

NIRS can evaluate changes in blood volume and oxygen levels in the brain while people exercise by measuring the absorption of this form of electromagnetic radiation by the blood, which varies depending on how much oxygen is present.

The team has found that even if you are healthy, there could be an upper limit on just how hard you can push yourself, because brain activity begins to be affected detrimentally as you push harder and harder.

The study watched blood flow and volume as well as measuring carbon dioxide breathed out during an incremental exercise test. In the tests, exercise intensity is gradually stepped up until the volunteers reach exhaustion and must stop. The observed fall off in carbon dioxide levels coincided with decreased blood flow to the brain, which affects exercise capacity, the researchers say.

You can find out more about the science behind the exercise threshold here. Of course, if you are not pushing your exercise regime to the limits, then you probably have nothing to worry about. More to the point, the research is aimed at fine tuning finely tuned athletes and others, not providing the sedantary or mediocre with an excuse to give up half way through their treadmill cycle. (Ahem, mentioning no names…)

Magnetic control

MRI robot Think of MRI and most people think of medical scanning, the kind of analytical tool that can slice through your brain or other organs, virtually speaking, and produce a three-dimensiona view of your innards. But researchers in Canada are putting the magnetic in magnetic resonance imaging to a different. They hope to use it to control tiny robot devices that can be guided through blood vessels in an application reminiscent of 1960s sci-fi movie Fantastic Voyage.

The demonstration by Sylvain Martel of the NanoRobotics Laboratory at Montreal Polytechnic School could herald the emergence of a new form of surgery that uses MRI to control “untethered” devices within the body. The team has spent the last several years developing microelectrochemical systems (MEMS) that could be used in diagnostics and treatment and have now successfully guided, an inactive prototype device for the first time through an artery (see picture) using computer-controlled MRI. More details here.

A New Look at Neopentane’s Chirality

The absolute configuration of a subtly chiral molecule has been determined using Raman optical activity and quantum mechanics. Werner Hug and his colleagues at the University of Fribourg, Switzerland, obtained the configuration of (R)-[2H1, 2H2, 2H3]-neopentane a molecule in which the central carbon is surrounded by four methyl groups bearing differing numbers of hydrogen isotopes.

For those who don’t know, a molecule is chiral (or handed) by definition if the left and right hand forms cannot be superimposed on to each other (a pair of hands, or gloves, for that matter are archetypally chiral (which comes from the Greek for hand).

The left and right-handed forms, or enantiomers, of (R)-[2H1, 2H2, 2H3]-neopentane are so similar that chemists had consigned this oddity to the lab shelf having given up any hope of distinguishing between its enantiomers. But not Hug. He and his colleagues were determined to push the limits of Raman spectroscopy to take this molecule back off the shelf and provide us with new insights into the nature of chirality.

Chirality itself lies at the heart of life on earth, but understanding the origin of the homochirality seen in nature remains a serious challenge, the new insights from Hug et al provides an important clue as to how isotopes may have played a role.

Hug et al publish details of their work in Nature.

InChI=1/C5H12/c1-5(2,3)4/h1-4H3/i1D,2D,3D

How to produce static electricity with water

Yesterday, we ran a video showing you a water powered battery that can generate a 15kV spark using nothing more than some simple hardware and a professor who looks a bit like Einstein. Some readers may have worried that it was a spoof given the date (April 1) but this is a genuine piece of science based on the principles of static electricity.

Water is a polar molecule – there is a small difference in electric charge from one end to the other – but pure (deionized) water is also a very good insulator. As the droplets of water fall through the bottomless metal cans, their polarity induces a charge in the cans (which are by the way heavily insulated from earth (or ground). A positive charge builds up on the cans as the water molecules falling into the buckets become negative. This results in a charge separation or a potential difference between the paint cans and the buckets of water (which are also heavily insulated from earth).

Eventually the potential difference reaches a threshold at which point the insulating properties of the air between the two balls breaks down and a spark leaps across the gap. This spark, which has a temperature of several thousand degrees Celsius carries a voltage of between 10 and 15 thousand Volts, far more than you need to power even the biggest set of plugin speakers for your mp3 player.

Several questions remain. Where does the energy come from to create this enormous potential difference and could this form of electricity be tapped by building some kind of power station at the top of a waterfall and using two enormous cans and buckets? Well to answer the first question just look at the vertical arrangement of the equipment. The energy comes from gravity, from the potential energy of the water, which is above the paint cans. The second question is a little more complicated to answer. It would be possible to build a bigger generator, although insulating the components from earth would be tougher and the dissolved salts in river water would make it far less efficient than a generator using deionized water, but those are probably not the main issues.

Think about it, to make electricity generation useful we need a current to flow. How might you “tap” off a current from this type of generator when its product is effectively small-scale lightning? A capacitor in the spark zone, you say? But then isn’t the air acting as a capacitor, still doesn’t solve the problem of tapping off a current. Find an efficient and safe way to tap the power of lightning and you could make a fortune and solve the world’s energy needs. But, please don’t try those kinds of experiment at home!

Instead of generating static electricity, however, it is possible to use gravity’s power to move water to produce a current, much more readily…think water wheel, dynamo-type generator…think hydroelectric dam.

By the way, this experimental setup was originally devised by Lord Kelvin in the nineteenth century and is known as Kelvin’s Thunderstorm, it featured in Bill Beaty’s amateur scientist column in 1995, you can find a more detailed explanation there.

Water-powered mp3 Player

UPDATE: 31st March 2011 In hard times, humour is often all we have to lift our spirits. Given the current situation in Japan regarding the state of their nuclear power stations following the tragic and devastating earthquake and tsunami, a twitter follower, Christophe Shiffert thought this electric sweet potato funny enough to tweet about it and to allude to the constantly unfolding tragedy that is humanity’s failure to address the problem of energy in more creative and sustainable ways.

In this week’s video, MIT’s Walter Lewin demonstrates how to produce 10 to 15000 volts of electricity using a couple of empty paint cans, a bucket of water, some wire, and two balls. The question is how does this work and could you use it like the potato powered mp3 player?

I’ll look forward to seeing your suggestions in the comments and will post a more detailed explanation the the answers tomorrow.

Alchemy bonus

The Alchemist this week discovers how a bodybuilders’ supplement might help treat Parkinson’s disease, the route taken by mercury from groundwater to coast, and how to boost your storage space with fullerenes. Also this week, physical condensation problems solved and how Raman spectroscopy is laying it on thin to help scientists understand carbon sheets. And, this week’s award goes to Perry McCarty for his pioneering work in understanding waste water chemistry and microbiology. Alchemical happenings on ChemWeb

If you missed the previous instalment, we discovered proof positive that Asian pollution could affect global weather, how to scratch fatty acids from the surface of stone buildings, and discovered hundreds of new drug targets for the battle against cancer. We also did a spot of spring cleaning with a new type of duster for mopping up even the tiniest toxic particles and found out how filling up in the UK became more expensive than ever thanks to an inadvertent silicon injection into fuel. Find out more in the older Alchemist

Cool cats make heavy metal fallout

The rapid adoption by the car industry of catalytic converters for petrol engines to reduce NOx and other pollutants has significantly improved the quality of air in busy towns and cities. However, Italian scientists says this improvement has comes at a significant price as they are finding rapidly rising levels of heavy metal fallout that could have serious implications for health.

Claudio BotrÃ¨ of the University of Rome and Alessandro Alimonti of the Italian National Institute of Health in Rome and their colleagues explain that the increasing numbers of catalytic converters on the road has led to rising environmental levels of the metals used as the catalysts in these devices – platinum, rhodium, palladium, and iridium. The team has published their detailed findings in the International Journal of Environment and Health.

More on this in a media release on AlphaGalileo

Hey good looking, what you got cooking, in those genes?

Attractive people Here’s a puzzle. If evolution ensures that ‘good’ genes spread through a population, then why are individuals so different? Why don’t people get better and better looking through each generation to the detriment of ugliness and lead to a population of real lookers?

The problem with current evolutionary theory is that it would seem that if females select the most attractive mates, then the genes responsible for their attractive features would spread quickly, leading to all males becoming equally attractive (think peacock tails). Ultimately, further sexual selection would then no longer take place and evolution would stop in its tracks.

This is the so-called lek paradox and it has remained a foil in the weaponry of the intelligent design advocate’s arsenal for many years. Until now.

Thanks to research at Newcastle University, England, this apparent fundamental flaw in Darwin’s theory of evolution, latched on to by creationists can be explained quite effectively by evolution itself. The findings of Newcastle’s Marion Petrie and Gilbert Roberts research suggests that sexual selection leads to increased genetic diversity by a mechanism not previously understood.

Petrie reasoned that as genetic mutations occur naturally anywhere in the genome, some will actually affect those used to produce the DNA repair kit enzymes found in all cells. This would lead to those individuals with a malfunctioning or inefficient repair kit, having more mutations left unrepaired and so greater variation in their genome.

Usually, damaged DNA leads to an unviable organism that either dies quickly of the effects or is otherwise unable to reproduce. However, if those variations are present in sections of the genome responsible for disease defence, then variation can actually be beneficial as greater variation in the genome at these points means more chance of warding of bacteria and viruses.

Petrie modelled the spread of genes in a population and demonstrated that the tendency towards reduction in genetic diversity caused by sexual selection is outweighed by the maintenance in greater genetic diversity generated by mutations affecting genome repair.

The researchers began this research a decade ago and their model genes are now a great fit for the observations of variations. “We find that sexual selection can promote genetic diversity despite expectations to the contrary,” Petrie says. The team publishes details of their findings today in the journal Heredity.

With this Ring

Bishnu Khanal and Eugene Zubarev of Rice University in Houston, Texas have found that nanoscopic gold roads coated with polymer can spontaneously self-assemble into rings within seconds of water droplets condensing on to the surface of a solution of the rods in dichloromethane solvent.

Nanoscale objects organized into superstructures are interesting because the properties of such tiny particles depend not only on their composition, shape, and size, but also to a large extent on their spatial distribution and the degree of their ordering within a superstructure.

Images obtained with an electron microscope show that the nanorods in the rings are oriented randomly when their concentration in the original solution is high. However, at lower concentrations the result is truly amazing: The nanorods are oriented in a head-to-tail sequence along the edge of the ring.

The team reports details of their results in Angewandte

Beating Heart Disease with Vitamin B Drugs

Niacin is involved in the metabolism or carbohydrates, fats and proteins, but at high dosage it can increase HDL more than a third and reduce levels of “artery-clogging” triglycerides by half.

Graeme Semple of Arena Pharmaceuticals, San Diego, reports how new drugs that raise high-density lipoproteins, so-called good cholesterol might be developed by following the lead of familiar B vitamin, niacin.

Researchers at Arena and elsewhere are trying to develop new drugs that are even more effective than niacin and so could have greater potential to protect at-risk people against heart attacks and stroke. Semple discusses the latest developments at the ACS annual meeting today.

You can read more about the biochemistry of niacin and LDL cholesterol in Sciencebase.

InChI=1/C6H5NO2/c8-6(9)5-2-1-3-7-4-5/h1-4H,(H,8,9)/f/h8H