Resveratol and Longevity. Xanya Sofra Weiss

Researchers at the Harvard Medical School and the National Institute of Aging report that a natural substance found in red wine, known as resveratrol, offsets the bad effects of a high-calorie diet in mice and significantly extends their lifespan.

Their report, published electronically today in Nature, implies that very large daily doses of resveratrol could offset the unhealthy, high-calorie diet thought to underlie the rising toll of obesity in the United States and elsewhere, should people respond to the drug as mice do.

Resveratrol is found in the skin of grapes and in red wine and is conjectured to be a partial explanation for the French paradox, the puzzling fact that people in France to enjoy a high-fat diet yet suffer less heart disease than Americans.

The researchers fed one group of mice a diet in which 60 percent of calories came from fat. The diet started when the mice, all males, were 1 year old, which is middle-aged in mouse terms. As expected, the mice soon developed signs of impending diabetes, with grossly enlarged livers, and started to die much sooner than mice fed a standard diet.

Another group of mice was fed the identical high-fat diet but with a large daily dose of resveratrol. The resveratrol did not stop them from putting on weight and growing as tubby as the other fat-eating mice. But it averted the high levels of glucose and insulin in the bloodstream, which are warning signs of diabetes, and it kept the mice's livers at normal size.

Even more strikingly, the substance sharply extended the mice's lifetimes. Those fed resveratrol along with the high-fat diet died many months later than the mice on high fat alone, and at the same rate as mice on a standard healthy diet. They had all the pleasures of gluttony but paid none of the price.

The researchers, led by David Sinclair and Joseph Baur at the Harvard Medical School and by Rafael de Cabo at the National Institute of Aging, also tried to estimate the effect of resveratrol on the mice's physical quality of life. They gauged how well the mice could walk along a rotating rod before falling off, a test of their motor skills. The mice on resveratrol did better as they grew older, ending up with much the same staying power on the rod as mice fed a normal diet.

The researchers hope their findings will have relevance to people too. Their study shows, they conclude, that orally taken drugs "at doses achievable in humans can safely reduce many of the negative consequences of excess caloric intake, with an overall improvement in health and survival."

Several experts said that people wondering if they should take resveratrol should wait until more results were in, particularly safety tests in humans. "It's a pretty exciting area but these are early days," said Dr. Ronald Kahn, president of the Joslin Diabetes Center in Boston. Information about resveratrol's effects on human metabolism should be available a year or so, he said, adding, "Have another glass of pinot noir � that's as far as I'd take it right now."

The mice were fed a hefty dose of resveratrol, 24 milligrams per kilogram of body weight. Red wine has about 1.5 to 3 mg of resveratrol per liter, so a person would need to drink from 10 to 20 bottles of red wine a day to get such a dose. Whatever good the resveratrol might do would be negated by the sheer amount of alcohol.

Dr. Richard Hodes, director of the National Institute of Aging, which helped support the study, also said that people should wait for the results of safety testing. Substances that are safe and beneficial in small doses, like vitamins, sometimes prove to be harmful when taken in high doses, he said.

One person who is not following this prudent advice, however, is Dr. Sinclair, the chief author of the study. He has long been taking resveratrol, though at a dose of only 5 milligrams per kilogram. Mice given that amount in a second feeding trial have shown similar, but less dramatic, results as those on the 24 milligram a day dose, he said.

Dr. Sinclair has had a physician check his metabolism, because many resveratrol preparations contain possibly hazardous impurities, but so far no ill effects have come to light. His wife, his parents, and "half my lab" are also taking resveratrol, he said.

Dr. Sinclair declined to name his source of resveratrol. Many companies sell the substance, along with claims that rivals' preparations are inactive. One such company, Longevinex, sells an extract of red wine and knotweed that contains an unspecified amount of resveratrol. But each capsule is equivalent to "5 to 15 5-ounce glasses of the best red wine," the company's Web page asserts.

Dr. Sinclair is the founder of a company, Sirtris Pharmaceuticals, that has developed several chemicals designed to mimic the role of resveratrol but at much lower doses. Sirtris has begun clinical trials of one of these compounds, an improved version of resveratrol, with the aim of seeing if it helps control glucose levels in people with diabetes. "We believe you cannot reach therapeutic levels in man with ordinary resveratrol," said Dr. Christoph Westphal, the company's chief executive.

Behind the resveratrol test is a considerable degree of scientific theory, some of it well established and some yet to be proved. Dr. Sinclair's initial interest in resveratrol had nothing to do with red wine. It derived from work by Leonard Guarente of the Massachusetts Institute of Technology, who in 1955 found a gene that controlled the longevity of yeast, a single-celled fungus. Dr. Guarente and Dr. Sinclair, who had come from Australia to work as a post-doctoral student in Dr. Guarente's lab, discovered the mechanism by which the gene makes yeast cells live longer. The gene is known as sir-2 in yeast, sir standing for silent information regulator, and its equivalent in mice is called SIRT-1.

Dr. Guarente then found that the gene's protein needs a common metabolite to activate it and he developed the theory that the gene, by sensing the level of metabolic activity, mediates a phenomenon of great interest to researchers in aging, the greater life span caused by caloric restriction.

Researchers have known since 1935 that mice fed a calorically restricted diet � one with all necessary vitamins and nutrients but 40 percent fewer calories � live up to 50 percent longer than mice on ordinary diets.

This low-calorie-provoked increase in longevity occurs in many organisms and seems to be an ancient survival strategy. When food is plentiful, live in the fast lane and breed prolifically. When famine strikes, switch resources to body maintenance and live longer so as to ride out the famine.

Researchers had long supposed that the increase in longevity was a passive phenomenon: during famine or on a low-calorie diet, organisms would have lower metabolism and produce less of the violent chemicals that oxidize tissues. But Dr. Guarente and Dr. Sinclair believed that longer life was attained by an active program that triggered specific protective steps against the diseases common in old age. It was because these diseases were averted in calorie restriction, they believed, that animals lived longer.

Most people find it impossible to keep to a diet with 40 percent fewer calories than usual. So if caloric restriction really does make people as well as mice live longer � which is plausible but not yet proved � it would be desirable to have some drug that activated the SIRT-1 gene's protein, tricking it into thinking that days of famine lay ahead.

In 2003 Dr. Sinclair, by then in his own lab, devised a way to test a large number of chemicals for their ability to mimic caloric restriction in people by activating SIRT-1. The champion was resveratrol, already well known for its possible health benefits.

The experiment reported today tests one aspect of caloric restriction, the reduction in metabolic disease. Calorically restricted mice also suffer less cancer and heart disease, and there is some evidence that neurodegenerative diseases are also held at bay.

Critics point out that resveratrol is a powerful chemical that acts in many different ways in cells. The new experiment, they say, does not prove that resveratrol negated the effects of a high-calorie diet by activating SIRT-1. Indeed, they are not convinced that resveratrol activates SIRT-1 at all. "It hasn't really been clearly shown, the way a biochemist would want to see it, that resveratrol can activate sirtuin," said Matt Kaeberlein, a former student of Dr. Guarente who now does research at the University of Washington in Seattle. Sirtuin is the protein produced by the SIRT-1 gene.

Dr. Sinclair said experiments at Sirtris have essentially wrapped up this point. But they have not yet been published, so under the rules of scientific debate he cannot use them to support his position. In his Nature article he therefore has to concede, "Whether resveratrol acts directly or indirectly through Sir2 in vivo is currently a subject of debate."

Given that caloric restriction forces a tradeoff between fertility and lifespan, resveratrol might be expected to reduce fertility in mice. For reasons not yet clear, Dr. Sinclair said he saw no such effect in his experiment.

If resveratrol does act by prodding the sirtuins into action, then there will be much interest in the new class of sirtuin activators now being tested by Sirtris. Dr. Westphal, the company's chief executive, has no practical interest in the longevity-promoting effects of sirtuins and caloric restriction. For the Food and Drug Administration, if for no one else, aging is not a disease and death is not an end-point. The F.D.A. will only approve drugs that treat diseases in measurable ways, so Dr. Westphal hopes to show his sirtuin activators will improve the indicators of specific diseases, starting with diabetes.

"We think that if we can harness the benefits of caloric restriction, we wouldn't simply have ways of making people live longer, but an entirely new therapeutic strategy to address the diseases of aging," Dr. Guarente said.

Xanya Sofra Weiss

Xanya Sofra Weiss

Carpal Tunnel Supplements

Just inside your wrist is a narrow, bony passage called the carpal
tunnel. Anything but empty, this tunnel contains nine tendons as well
as a nerve called the median nerve, all of which are encased,
sausage-like, in a slippery sheath called the synovium. When the
synovium and tendons become inflamed and swollen, they squeeze the
median nerve, which runs to the fingers.

Ever watch a live
electrical wire rub metal? The pinched median nerve can send angry
sparks of pain, numbness and tingling from your fingertips to your
shoulder. More often the pain is in the thumb and the index and middle
fingers. Sometimes the ring finger is also involved. Many people who
suffer from CTS say it feels like their hands have fallen asleep;
others complain of weak grips and stiff fingers.

Women seem to
suffer from CTS more often than men. Changes in female hormones caused
by pregnancy, taking birth control pills and menopause somehow make the
synovium swell. And because women generally have small wrists, just a
little swelling is enough to cause carpal tunnel pain, experts say.

Surgeons agree that CTS should not be treated with surgery during pregnancy. Studies by Dr. Ellis found that vitamin B₆
helped relieve CTS in 11 percent of the pregnant women with severe CTS
signs and symptoms during their pregnancies. These women were treated
with 50 to 300 milligrams of B₆ daily for at least 60 to 90
days before giving birth. And there was no harm to either the mother or
the child. If you'd like to try this therapy, you should discuss it
with your doctor.

Obesity creates a similar situation. "There
is about a fivefold increase in CTS in people who are obese and couch
potatoes. So we encourage them to be in better shape and lose weight,"
says Morton Kasdan, M.D., clinical professor of plastic surgery at the
University of Louisville in Kentucky and clinical professor of
preventive medicine and environmental health

at the University of Kentucky in Lexington.

CTS has also become the unofficial health complaint of the modern age,
the result of an increase in cases among people in manufacturing jobs.

Officials at the U.S. Bureau of Labor Statistics don't keep records of
the number of CTS cases reported each year. Between 1986 and 1992,
cases of "repetitive trauma disorders" (a category that includes CTS
and similar conditions) zoomed from 50,000 to 282,000.

Another
common culprit is working on a computer, which doesn't require you to
take frequent breaks, as changing paper in a typewriter would. "The
repetitive activity produces inflammation, and this leads to swelling,"
explains Dr. Tunell. "That's a major contributor for the patients I
see."

Food Factors The pain hits your wrist, your hand and sometimes even your shoulder. But carpal tunnel syndrome can start in your stomach. Here are some things to consider. Hold the reins on cocktails. Alcohol is known to deplete the body of nutrients, especially the B vitamins, which are vital for preventing carpal tunnel syndrome. Drop those pounds. Many doctors have noted that people who lose weight sometimes also lose their symptoms of carpal tunnel syndrome. If you're on a weight-reducing diet, be sure to eat foods that contain vitamin B6, such as bananas and avocados.

Prescriptions for Healing Many doctors recommend B vitamins for carpal tunnel syndrome. Because even the foods richest in vitamin B6, such as bananas, avocados, brewer's yeast and beef, provide barely a single milligram of B6, you'll probably need to take a supplement. B-complex capsules often include all of the recommended vitamins. Nutrient Daily Amount Biotin 300 micrograms Riboflavin 25 milligrams Vitamin B6 50-200 milligrams MEDICAL ALERT: Take vitamin B6 in amounts above 100 milligrams only under the supervision of your doctor.

The Benefits of B₆

Doctors are divided on why vitamin B₆ seems to provide relief from CTS.

The author of five published studies that demonstrate the benefits of vitamin B₆ for CTS, Dr. Ellis contends that synovium swelling and inelasticity are caused by a B₆ deficiency.

Dr. Ellis and Karl Folkers, D.Sc., Ph.D., professor and director of the
Institute for Biomedical Research at the University of Texas at Austin,
once healed 22 of 23 people with CTS just by giving them 50 to 300
milligrams of vitamin B₆ daily for at least 12 weeks. And a number of them had already undergone surgery without experiencing relief. "Vitamin B₆ is as important to your body as oxygen and water, only it takes a little longer to show the benefits," says Dr. Ellis.

The average diet, Dr. Ellis says, provides only about 1.4 milligrams of vitamin B₆
a day, in part because the nutrient is lost in processing, so many
people are just not getting enough. "Raw foods are the best sources,
because heat destroys it," he says. Foods containing B₆ include potatoes, bananas, chicken breast, top round of beef, fish, brown rice and avocados.

Other doctors believe vitamin B₆
acts as a diuretic, helping the body to eliminate excess fluid. "During
pregnancy, your feet swell, your hands swell, rings don't fit anymore.
You're retaining fluid, especially in the wrists," says Dr. Tunell. For
some women, the problem worsens when they lie down, as fluid that makes
the ankles swell during the day is redistributed throughout the body,
including to the wrists, he says. "B₆ helps you get rid of the extra water gain that's causing carpal tunnel," he says.

Another theory, backed up by two European studies, suggests that vitamin B₆ somehow short-circuits an angry nerve's ability to transmit pain signals. "We don't know the mechanism, but we do know B₆
reduces the amount of pain that animals feel, and that may be what's
happening here," says Allan L. Bernstein, M.D., chief of neurology at
Kaiser Permanente Medical Center in Hayward, California.

Medical experts do agree on one thing: No matter how vitamin B₆
gets the job done, you have to be careful not to take too much. In
studies using laboratory animals, researchers found that excess B₆ can harm your central nervous system.

Researchers at the U.S. Department of Agriculture Western Human Nutrition

Research Center in San Francisco fed 12 experimental animals 1, 10, 100, 200 or 300 times their requirement of vitamin B₆ for seven weeks. At the three highest levels of B₆ intake, the animals' reaction time to a loud noise was reduced. Signs of a B₆ overdose also include an oversensitivity to sunlight, which produces a skin rash and numbness.

"Vitamin B₆ toxicity symptoms are rarely seen in healthy individuals. Moderate supplementation of B₆ will not cause that kind of thing," says Robert A. Jacob, Ph.D., research chemist in micronutrients at the Western Human Nutrition

Research Center. "You'd have to megadose on it. So I don't think that
would happen if you take just a multivitamin/mineral supplement with B₆ or even a 50- or 100-milligram B₆ supplement. It appears only when you chronically take massive amounts."

Doctors recommend 50 to 200 milligrams of vitamin B₆ daily to treat carpal tunnel.

Some Recommend Riboflavin and Biotin

There's some evidence that vitamin B₆
won't work properly unless you're getting adequate amounts of
riboflavin and biotin, other B vitamins. "Each one of these vitamins is
synergistic; each works in concert with the other," says Flora Pettit,
Ph.D., a research scientist at the Biochemical Institute at the
University of Texas at Austin. Doctors suggest aiming for 300
micrograms of biotin and 25 milligrams of riboflavin daily.

By
law, most cereals, flours and other grain products are fortified with
riboflavin; milk, yogurt and cheeses are good sources, too. Biotin is
found in brewer's yeast, soy flour, cereals, egg yolks, milk, nuts and
vegetables.

Older adults, alcoholics and those with nutritionally poor diets
are at particular risk for deficiencies in these vitamins, says Dr.
Tunell. "Generally, the elderly have poor diets, and they have trouble
absorbing B vitamins anyway," says Dr. Tunell. "So they couldn't go
wrong with a B-complex supplement unless they have Parkinson's disease.
In that case, vitamin B₆ may interfere with the absorption of their levodopa medication."

"My patients are getting between 50 and 100 milligrams of vitamin B₆ and riboflavin a day, using a B-complex supplement," says Dr. Kasdan. "And 60 percent of them have gotten better."

Most doctors agree that catching CTS early is a key to successful treatment. "If you have severe carpal tunnel, the vitamin B₆
isn't really going to reverse it," says Dr. Bernstein. "But if you
catch it early, when you're just starting to have pain and tingling,
and if there's no weakness and it bothers you at night but not during
the day, you'll do extremely well."

http://xanya-sofra-weiss.palaweb.com/info-xanya_sofra_weiss-nanotechnology

Xanya Sofra Weiss

PHOTOELECTROCHEMICAL PROPERTIES OF MELANIN

Arturo Solis1, Maria E. Lara2 and Luis E. Rendon

Melanin is to the animal kingdom like chlorophyll to the vegetal kingdom1.
Melanin collects energy from lower-energy radiation sources, kicks electrons
into excited states, initiating a process that would end up producing chemical
energy, similar to the way in which photosynthesis supplies energy to plants.
However, the precise roles of melanin during this process are unknown. Here we
show that the increase in the electron-transfer properties of melanin is
independent of the energy of the incident photons. We found in controlled in vivo
assays that melanin has the remarkable capability of converting lower-energy
radiation towards a more useful form of energy. Furthermore, we found that
melanin can break up water molecules and giving up energy suggesting an
additional behavior mode for melanin. Our results demonstrate how members of
the melanin family are likely to function as transducers, oxidizing water, pushing
apart water molecules, as well as recruiting back ions into molecules that are
subsequently polarized again. Melanin drives the photon energy of lower-energy
radiation sources by quenching electrons and initiating an ionic event
independently of their relative energy contention. We anticipate our assay to be
a starting point for more sophisticated photoelectrochemical applications. For
example, the individual and combined action of multiple photovoltaic
applications could be tested, including conducting polymers, for example poly-
(phenylenevinylene) (PPV) derivatives or C60 particles. Furthermore, melanin’s
energy conversion ability is a major target of solar energy conversion
development, and an organic-semiconductor way for photoelectrochemical
applications will be relevant for such developments.
Organic active materials electronic circuits, displays, and sensors will enable a
future generation of electronic products that may eventually enter the
mainstream electronic market. The motivation in using organic active materials
come from their ease in tweaking and matching electronic and processing
properties by chemical design and synthesis, low cost processing based on low
temperature processes, mechanical flexibility, and compatibility with flexible
substrates2 . Within these is the family of organic materials, “The Melanins”. For the
sake of simplicity “melanin” will be used in a generic and unqualified sense,
referring primarily to a synthetic, dopa made form of eumelanin. Melanin can be
envisaged as an energy transducer with the properties of an amorphous
semiconductor; it can absorb many different types of energy and convert it in
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another more useful type of energy. In a very enlightening paper, Michael
Grätzel3 looks into the historical background, present status and development
prospects for a new generation of photovoltaic cells, the photoelectrochemical
cells. Until now, the conversion of sunlight to electrical power has been
dominated by solid state junction devices, often made of silicon. But this
dominance we foresee will fall by the emergence of these new “melanincompound”
made photovoltaic cells, based on their here reported new
photoelectrochemical, conducting, polymer type properties. Melanin offers the
prospect of easy fabrication together with other attractive features, such as low
cost. This extra special new property of melanin will result in a huge progress in
fabricating photoelectrochemical cells and will open up whole new vistas of
opportunity. Contrary to expectation, we have proven that some of the made
by us new devices have strikingly high conversion efficiencies, which compete
with those of conventional devices.
Melanin has proven to be an intractable system to study, in part due to their
strong binding with a protein host under in vivo conditions. It is not understood
whether this protein host is a left-over from the bio-synthesis, or whether it is
crucial for the functionality. Strictly speaking, the term “melanin” should
encompass both the chromophore and the associated protein. However, it has
become the norm to use the term to refer only to the chromophore (the
nominally functional part). The vast majority of studies on the natural system
removes (or ignore) the protein and all studies on synthetic melanin involve the
chromophore only. Unfortunately, the chromophores themselves are virtually
insoluble in most common solvents, and have defied systematic attempts at
characterization by standard analytical methods. The predominant strategy in
the field is to study the photochemical and photophysical properties of isolated
natural models or synthetic analogues without recourse to any consistent
structural model.
Dopa-melanin was synthesized from DOPA (dihydroxyphenylalanine) following
the auto oxidizing procedure4. There is a general agreement that melanin are
macromolecules of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-
carboxylic acid (DHICA). The proportion of these two components in the final
macromolecule varies depending upon the type of natural melanin or the
synthetic route. Recently, melanin have attracted the attention of molecular
biophysicists and the soft matter and functional organic materials communities.5
melanin, possesses an intriguing and rather unique set of physicochemical
properties: strong broad band UV and visible absorption; non-radiative
conversion of photo-excited electronic states approaching unity (extremely low
radiative quantum yield)6; powerful anti-oxidant and free radical scavenging
ability7; and probably most bizarrely of all, electrical conductivity and
photoconductivity in the condensed phase8-9. In relation to the last two
properties, it has even been speculated that melanin may be a bio-organic
semiconductors. In figure 1 it is shown the absorbance as a function of
wavelength of a typical synthetic eumelanin aqueous (0.0025%/wt) solution10.
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Our melanin samples have shown very interesting photoelectrochemical
properties. The relation between activity-structure of this polymer was noticed as
the result of our detailed observations in human retina in vivo, while studying the
three main causes of blindness (glaucoma, diabetes, degeneration by age). We
noticed the effect in glioma growth and angiogenesis of melanin presence in
the ocular liquid, the oxygen content increased up to 34 % which did not come
from ATP. We were initially trying to control angiogenesis by studying the
proangiogenic and antiangiogenic factors and it is well known that one of the
most antiangiogenic factors is a high level of oxygen11. Oxygen has a very
important presence, and their quantity an activity is determinant in the evolution
of these diseases. The explanation about their biological activity and presence in
the ocular liquid can not be separated from melanin presence. Because there is
not a clear understanding of how UV and visible radiation interacts with
melanin’s macromolecule to generate properties such as the monotonic broadband
absorbance12. In an attempt to gain new insight into the dynamics of
energy dissipation in melanin under physiological conditions, Forest and Simon13
undertook a wavelength dependent photo acoustic study. They found (as per
radiative quantum yield measurements) that the majority of absorbed energy is
dissipated non-radiatively within a nanosecond of excitation. However, when the
melanin was excited with 264 nm radiation c. 30% of the absorbed energy was
retained for a period longer than a few hundred nanoseconds. This is an
important contribution because it suggests that UV radiation with wavelengths
below 300 nm generates a longer lived excited state with a significant yield,
which in turn may result in excited state photochemistry, which does not occur
under visible light stimulation.
The observations of their biological effects, allow us, to elucidate the protective
effects on human retinal tissue of melanin, undoubtedly due to melanin’s
oxidizing effect on water, liberating oxygen and separating it from protonichydrogen.
Melanin quenches the photons, and with this energy, breaks the
water molecule; absorption of light by this pigment initiates an ionic event and a
reaction that increases the level of oxygen 34 % in surrounding tissues and even
higher in the ocular liquid. This increased energy event in the human eye is the
first step to initiate the vision phenomenon. A great part of the photonic energy is
transformed by melanin into chemical energy by means of hydrogen generation
which acts as an energy carrier, and throughout the action of NADH and FADH,
gives up this energy to the cell, finally the cell uses it to energize some of the
main chemical reactions that enable vision. Without this energy; there is no vision
at all. Melanin in the ocular fluid has an additional characteristic; it supports the
opposite reaction, that is: back binding of hydrogen and oxygen and giving up
water and electricity. Melanin in human eye is for animal kingdom what
chlorophyll is for vegetal kingdom. Both molecules absorb photons, and initiate
an ionic event with large metabolic consequences. The melanin’s macromolecule
solution retains these properties outside the eye for months, even years,
unlike chlorophyll which is very unstable and totally inactive after 20 seconds
outside the leaf. Melanin’s function to other body structures, has shown to be
essential too and its medical applications are huge but out of scope of this
article.
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We claim that photosynthesis exists not only in vegetables, but in animals too.
Meredith14 question – where has all the excess energy gone? – can be
answered even without a satisfactory knowledge of the molecular structure of
the pigment granules, by saying “just set up a couple of electrodes” and you’ll
get melanin’s photoelectrochemical properties, to co-relate the measured
potential to a specific chemical activity.
We proceeded to test the photo electrochemical properties of melanin by
manufacturing a prototype cell (figure 2). We started with a very simple cell were
the electrolyte was a 1.3% solution of melanin in distilled water, cooper and
aluminum electrodes 2.5 cm apart, cooper wires (covered with silicon) where
attach to the electrodes by glued them down, we noticed that any kind of
welding affected the melanin’s behavior. The cell started to give up electricity
just a few minutes after being ensemble.
The output was similar to that of dye-sensitized solar cells, the output was
remarkably stable even under light soaking for more than 10,000 h. see figure 3.
We believe that developing these prototypes could have a significant impact on
the alternative energy sources research.
As Grätzel3 says, the pioneering photoelectric experiments were done with liquid
not solid state devices, the foundation of modern photoelectrochemistry was
laid down by the work of Brattain and Garret15 and subsequently Gerischer16 who
undertook the first detailed electrochemical and studies of the semiconductor–
electrolyte interface. Research on photoelectrochemical cells went through a
frantic period after the oil crisis in 1973, which stimulated a worldwide quest for
alternative energy sources. Within a few years well over a thousand publications
appeared (see ref. 17 for a list). Most of the investigations focused on two types
of cells. The first type is the regenerative cell, which converts light to electric
power leaving no net chemical change behind. Photons of energy exceeding
that of the band gap generate electron–hole pairs, which are separated by the
electric field present in the space-charge layer. The negative charge carriers
move through the bulk of the semiconductor to the current collector and the
external circuit. The positive holes are driven to the surface where they are
scavenged by the reduced form of the redox relay molecule (R), oxidizing it: h+ +
R = Q. The oxidized form Q is reduced back to R by the electrons that re-enter
the cell from the external circuit. Much of the work on regenerative cells has
focused on electron-doped (n-type) II/VI or III/V semiconductors using
electrolytes based on sulphide/polysulphide, vanadium(II)/vanadium(III) or I2/I–
redox couples. Conversion efficiencies of up to 19.6% have been reported for
multijunction regenerative cells18. The second type, photosynthetic cells, operate
on a similar principle except that there are two redox systems: one reacting with
the holes at the surface of the semiconductor electrode and the second
reacting with the electrons entering the counter-electrode. In the example
shown, water is oxidized to oxygen at the semiconductor photo anode and
reduced to hydrogen at the cathode. The overall reaction is the cleavage of
water by sunlight. Titanium dioxide has been the favored semiconductor for
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these studies, following its use by Fujishima and Honda for water photolysis19.
Unfortunately, because of its large band gap, (3–3.2 eV) TiO2 absorbs only the
ultraviolet part of the solar emission and so has low conversion efficiencies.
Numerous attempts to shift the spectral response of TiO2 into the visible, or to
develop alternative oxides affording water cleavage by visible light, have so far
failed. The width of the band gap is the key about the prospects of
photoelectrochemical cells being able to give rise to competitive photovoltaic
devices, as those semiconductors with band gaps narrow enough for efficient
absorption of visible light. The width of the band gap is a measure of the
chemical bond strength. Conducting polymers, for example poly-
(phenylenevinylene) (PPV) derivatives or C60 particles, are attracting great
interest as photovoltaic materials20-25. Bulk donor–acceptor heterojunctions are
formed simply by blending the two organic materials serving as electron donor
(p-type conductor) and electron acceptor (n-type conductor). The advantage
of these new structures over the flat-junction organic solar cells investigated
earlier20 is the interpenetration of the two materials that conduct positive and
negative charge carriers, reducing the size of the individual phase domains to
the nanometers range. This overcomes one of the problems of the first
generation of organic photovoltaic cells: the unfavorable ratio of exciton
diffusion length to optical absorption length. An exciton is a bound electron–hole
pair produced by absorption of light; to be useful, this pair must reach the
junction and there dissociate into two free charge carriers — but excitons
typically diffuse only a few nanometers before recombining. Light is absorbed
(and generates excitons) throughout the composite material. But in the
composite, the distance the exciton has to travel before reaching the interface
is at most a few nanometers, which is commensurate with its diffusion length.
Hence photo-induced charge separation can occur very efficiently. Conversion
efficiency from incident photons to current of over 50% has been achieved with
a blend containing PPV and methanofullerene derivatives21. The overall
conversion efficiency from solar to electric power under full sunlight achieved
with this cell was 2.5%. Although these results are impressive, the performance of
the cell declined rapidly within hours of exposure to sunlight22. In contrast, the
output of dye-sensitized solar cells is remarkably stable even under light soaking
for more than 10,000 h. similar long-term stability will be required for large-scale
application of polymer solar cells.
DISCUSION
The second order structure array must be a graphite type array, that appear to
be composed not of a single chromophore type (whether they be extended
polymeric or smaller oligomeric systems), but rather of ensembles containing a
range of chemically distinct macromolecules (chemical disorder model).
Whatever the situation is this stacked oligomeric ‘proto-molecules’ consisting of
indolequinone units (we claim, they could easily be polyhydroxindole, figure 4),
arranged14 as figure 5 that appears to agree with the early X-ray diffraction
studies of Thathachari and Blois26. Will favor the formation of molecular orbital
arrangement, and we foresee that, this arrangement between layers will
Nature Precedings : hdl:10101/npre.2007.1312.1 : Posted 12 Nov 2007
6
accommodate the oxygen in such a way with the nitrogen that will generate a
very strong competition between them to produce protons; once a proton is
created the absorbed photon will provide the necessary energy to recombine
the water molecule with the concomitant product of an electron flow.
We should also not ignore the possibility that once the structure-property
problem is properly solved, designing melanin-inspired functional materials
becomes a real possibility for applications in organic sensors and
optoelectronics.

Xanya Sofra Weiss

Xanya Sofra Weiss

J. Oschman

The living matrix is defined as the continuous molecular fabric of the organism, consisting of fascia, the other connective tissues, extracellular matrices, integrins, cytoskeletons, nuclear matrices and DNA. The extracellular, cellular and nuclear biopolymers or ground substances constitute a body-wide reservoir of charge that can maintain electrical homeostasis and “inflammatory preparedness” throughout the organism. Recent research has emphasized the significance of charge transfer in relation to the scavenging or neutralization of free radicals delivered to sites of injury during and after the oxidative burst. Evidence comes from studies of the role of electrons in mitigating the consequences of inflammation when living systems are connected to the earth (earthing). The phenomenon helps explain how bodywork and movement therapies can facilitate the resolution of acute or chronic injuries, and how patients with inflammatory conditions may “deplete” a therapist during hands-on treatments. It is suggested that barefoot contact with the earth as well as hands-on and hands-off therapies facilitate healing by stimulating the migration of charges into sites of acute or chronic inflammation. One hypothesis to explain the effects of earthing is that charges from the ground substance reservoir prevent “collateral damage” to healthy tissues in the vicinity of an injury. A second hypothesis is that earthing allows electrons to replenish charge in the ground substance reservoirs, making electrons available throughout the body.

Arasys Perfector

perfector bioscience

natalie cole