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Tizer
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5150 Posts
Posted -  25/01/2008  :  13:01
Science News

Following suggestions, I have started this thread in the General Chat area to post occasional press releases describing science and technology news (they were previously in a sub-forum). I will post further science releases into this same thread unless OGFB readers say they prefer them to be in individual threads, i.e. one thread per news release. But tell me if you don't want them - I won't be offended!   Tizer

Here is the first news story...




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Tizer
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5150 Posts
Posted - 04/03/2008 : 11:41
Sue, thanks for your support. Yes, I trained as a scientist, worked in several different and interesting areas, and in universities and industry, then later moved into publishing. I've got access to press releases on science & technology and I thought if I selected some of the more generally interesting ones and posted them here they might provide a chance to get some of the info "from the horse's mouth" so to speak, instead of just from the newspapers and TV. Also, they might attract more people searching through the web search engines and give them a chance to discover the joys of OGFB as I did!

Stanley, that's fascinating about the sound signatures and about H&J themselves. I heard part of  a radio programme the other evening about a "sound recordist" who tried to get his mikes into unusual places, especially in the wild. He had put a mike into the carcass of an animal and left it for the vultures and hyenas etc so he could record the sounds of them feasting. That example doesn't appeal to me but we need people like that who look for different perspectives. He was challenged by seeing how cameramen "had it easy" because they could use telephoto lenses to film dangerous scenes from a distance or from a vehicle. So he wanted to do the same but with sound.


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Tizer
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5150 Posts
Posted - 04/03/2008 : 12:47
The following story shows how the food industry is able to make a lot of money out of obesity. Instead of changes in dietary calorie intake (energy intake) and lifestyle (energy expenditure), the idea seems to be to eat something that allows you to eat more. Conjugated linoleic acids (CLA) are fatty molecules found naturally in eggs, whole milk, butter and cheese, and to some extent in meat. Just the sort of foods that are being removed from many people's diets.

Obese children may benefit from CLA: study
(News story from NutraIngredients newsletter)

29-Feb-2008 - Supplements of conjugated linoleic acids (CLA), previously reported to have benefits for weight in adults, could also help children, and possibly aid in the fight against childhood obesity.
According to a new study using a piglet model of human infancy, researchers report in the March issue of the "Journal of Nutrition" that piglets receiving CLA gained 50 per cent less body fat than their non-supplemented litter mates.

The promising results, if repeatable in human children, could offer an interesting route to follow in the ongoing struggle with childhood obesity, which grew from 9.6 per cent in 1995 to 13.7 per cent in 2003 in the UK alone. EU figures estimate that around 14m EU children are currently overweight or obese, of which more than three million are obese.

This study adds to an ever growing body of research supporting CLA a weight management tool. Indeed, it underlines the notion that CLA may help loose weight without affecting lean body mass, which could become important in the face of a growing obesity problem.

The CLA market is expanding, according to a 2007 Frost & Sullivan report, which said the global market is forecast to reach revenues of US$109.9 million in 2013

Benjamin Corl from North Carolina State University randomly assigned 24 piglets to receive a low-fat (three per cent) or high-fat (25 per cent) milk formulas with or without a CLA supplement (one per cent) for 16 to 17 days.

The piglets fed the high-fat formula were found to gain 50 per cent more body fat than piglets fed either high-fat plus CLA or the low-fat formula, report the researchers.

Moreover, no changes to liver and muscle oxidation markers were reported by any of the dietary patterns, indicating the potential safety of CLA supplementation.

The North Carolina-based researchers also noted a reduction in the expression of acetyl-CoA carboxylase-alpha, a key enzyme in fatty acid synthesis, in fatty tissue.

"Overall, CLA reduced body fat accretion without influencing daily gain in a piglet model of human infancy," wrote Corl and co-workers.

"Results indicate that inhibition of fatty acid uptake and synthesis by adipose tissue, and not increased fatty acid oxidation in liver or muscle, were involved in reducing body fat gain," they concluded.

The promising results require confirmation in humans before CLA supplementation could be recommended for the fight against childhood obesity.

Growing body of science

The potential of CLA to help reduce fat mass in adults was supported by a meta-analysis of 15 randomised, double-blinded, placebo-controlled trials using mixtures of trans-10, cis-12 isomers.

The meta-analysis, led by Leah Whigham from the University of Wisconsin School of Medicine and Public Health, reported that, when these results were compared to those from the placebo tests, CLA improved fat loss at a rate of 0.024 kg per gram of CLA per week.

The food industry is increasingly active in the research and development of new ingredients and food formulations that could help combat the growing health problem of obesity.

Source: Journal of Nutrition
March 2008, Volume 138, Pages 449-454
"Conjugated Linoleic Acid Reduces Body Fat Accretion and Lipogenic Gene Expression in Neonatal Pigs Fed Low- or High-Fat Formulas"
Authors: B.A. Corl, S.A. Mathews Oliver, X. Lin, W.T. Oliver, Y. Ma, R.J. Harrell, J. Odle

Edited by - Tizer on 04/03/2008 12:47:22


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roopakvaidya
Regular Member


233 Posts
Posted - 05/03/2008 : 06:03
Tizer, you might find this interesting. A green car, powered by hydrogen. Why can't wind-mill power be used to separate Oxygen and Hydrogen from water?
http://news.bbc.co.uk/2/hi/technology/7265267.stm

Edited by - roopakvaidya on 05/03/2008 06:13:53 AM


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Stanley
Local Historian & Old Fart


36804 Posts
Posted - 05/03/2008 : 06:14

http://www.wipo.int/pctdb/en/wo.jsp?wo=2002077663 

http://www.nautronix.com/index.php?option=com_content&task=view&id=83&Itemid=86

A couple of links here which might interest you Tizer.  The underwater GPS was part of the work H&J did on underwater detection and battle space management.  You won't find a lot of info about it in the public domain, very hush hush.  Harry is dead now so they can't prosecute him for blabbing but he knew exactly what had happened to the Kursk as soon as they sent him the sound signature because there was a recording on the databse of a similar accident with Hydrogen Peroxide powered torpedoes on a British submarine.  Fascinating subject......


Stanley Challenger Graham




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Tizer
VIP Member


5150 Posts
Posted - 05/03/2008 : 10:17
Thanks Roopa, it's worthy of a full announcement!

Green sports car set for launch
BBC Online News, 3 March 2008 (abstracted).

A "zero-emission" sports car with a top speed of nearly 100mph is set to be unveiled at the Geneva Motor Show. The hydrogen-powered Lifecar, based on the design of the Morgan Aero-8 roadster, produces little noise and only water vapour from its exhaust. (The company said "We may have to supply headphones with the sounds of a five litre V8 linked to the throttle pedal".)

The lightweight model packs advanced fuel cells and an energy storage system that gives the car a range of 250 miles (400km) per tank of hydrogen. It has been developed by a consortium of UK companies and universities. "Figures suggest the car should be capable of doing 0-60 [miles per hour] in about seven seconds," Matthew Parkin of classic sports car manufacturer Morgan told BBC News. However, the exact acceleration will not be known until the complete car is taken for its first test drive. "It's nearly there and the plan is to drive it when the show is over," said Mr Parkin.

The £1.9m project to build the Lifecar, part funded by the UK government, has taken nearly three years. "The basic concept was to build an entertaining and fun sports car that would act as a showcase for the technology and would deliver 150 miles to the gallon," said Mr Parkin. Everything else has tumbled out from that."

The car is powered by a bank of lightweight hydrogen fuel-cells developed by UK defence firm Qinetiq. "If you took a typical internal combustion engine and replaced it with a fuel cell, the fuel cell would be very large," explained Ian Whiting of Qinetiq. "That's not an efficient way to do things." The fuel cells in the Lifecar produce about 22 kilowatts - roughly one fifth of the amount of power of a typical combustion engine. "With that we can provide all of the cruise capability we need to," he said. When the car needs to accelerate or climb a hill it draws extra power from a bank of ultra-capacitors aligned down the centre of the car.

"They are like a battery but they do not store quite as much energy and they allow the energy in and out much quicker," explained Mr Whiting. These are primarily charged by a regenerative braking system which slows the car by converting the vehicle's kinetic energy into useful electrical energy using a motor. "Hybrid cars already use regenerative braking - normally it restores about 10% of the energy," said Mr Parkin. "Lifecar is aiming for 50%."

The car has a range of about 250 miles (400km) and has a top speed of around 90mph (145km/h). "The whole thing has to be built around efficiency which comes down to weight at the end of the day," explained Mr Parkin. As a result, the car has an aluminium chassis and a lightweight wooden interior, including seats. It also doesn't have any of the "luxuries" such as a stereo, central locking or even airbags, found on many modern cars. "The objective is to get the weight down to 700kg." There are also other notable omissions such as a gearbox and - as the fuels cells produce little noise - the roar of an engine.

Other car manufacturers have shown off hydrogen-powered sports cars, although many have been conversions of existing models or hybrid cars that can also run on petrol. For example, Japanese manufacturer Mazda has unveiled a modified version of its RX-8, known as the Hydrogen RE, which uses a dual-fuel system. Honda has also announced that its petrol hybrid CR-Z sports car concept would launch in 2009.

However, the road to a hydrogen-fuelled future has a number of obstacles. Critics point out that to produce hydrogen by splitting water uses a large amount of electricity. At present, the majority of this electricity comes power stations burning fossil fuels and therefore brings no environmental benefit. In addition, there is little infrastructure for refuelling the vehicles. "There's a whole range of questions about how you [could roll out a hydrogen infrastructure] and when you could do that," said Mr Whiting. "For vehicles which have a central base you can readily install a system to refuel those." For example, hydrogen buses that return to a central depot already operate in many cities. An infrastructure to refuel personal hydrogen vehicles would take longer, he said. However, interim solutions do exist, such as so-called "reformer technology". "It allows you to take the existing fuel infrastructure - diesel for instance - and convert it into hydrogen on the vehicle," said Mr Whiting.

Other collaborators on the project were RiverSimple, Cranfield University, Oxford University and Linde AG.

Edited by - Tizer on 05/03/2008 10:24:15


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Tizer
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5150 Posts
Posted - 05/03/2008 : 10:22
Thanks Stanley and Roopa for raising these issues and providing the links. I ought to point out that though I have access to science & technology press releases I am not actively using them elsewhere now, so I can't personally raise their profile or the other issues that readers might post. But I hope and expect that journalists worldwide might find themselves on this thread via Google etc and pick up on some of these comments, sources etc.


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Tizer
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5150 Posts
Posted - 05/03/2008 : 10:23
Will the BBC iPlayer break the Internet?
The Internet Service Provider that I use, PlusNet, has just sent out the latest issue of its newsletter. One of the main topics is about the BBC iPlayer. With the iPlayer you choose what you want to watch and either play the programme through your computer as soon as it is available using a method known as streaming, or download it to your computer to watch when it suits you. A wide range of BBC TV programmes from the past seven days from most BBC television channels are available to download with BBC iPlayer.The problem is that "streaming" uses a massive amount of internet "bandwidth" and could slow down the internet to snail's pace or even block it completely. The newsletter reads as follows:

********************
BBC iPlayer - A bandwidth explosion

Since the BBC iPlayer was officially launched on Christmas Day there has hardly been a day go by without it appearing in the media. Recently coverage of the iPlayer has been massive and we'd like to offer our views on this phenomenon.

Last week BBC Director of Future Media and Technology Ashley Highfield claimed that "there has been negligible impact on the UK internet infrastructure" as a result of the iPlayer launch.

Well, we've been studying traffic since the launch and have witnessed a dramatic increase in usage which is down to the iPlayer. This is only going to increase as the BBC continue to promote their on-demand service and people start using it more regularly.

A recent Member Centre poll showed that 19% of respondents have not used iPlayer yet but will be doing so in the near future.

To learn more about the dramatic impact of the iPlayer, PlusNet suggests you read its blog: http://www.plus.net/go.html/iPlayer0208
********************

Comments in the PlusNet blog include:
* iPlayer usage is continuing to grow but at a slightly lower rate, up between 10% and 25% per hour comparing last week with the same week in January.

* iPlayer streaming outnumbers downloads by 8 to 1.

* iPlayer usage now accounts for approximately 5% of PlusNet's network capacity.

* Back at the beginning of November streaming during evening hours was using around 4-5% of the network but as at the middle of February it's around 9-10%.


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Stanley
Local Historian & Old Fart


36804 Posts
Posted - 05/03/2008 : 16:56
I heard a fascinating insight into the BBC 'Listen Again' feature.  The reason the progs are only on the site for a week is because of copyright issues.  However, if it is in an archive elsewhere on the web as an podcast the restriction doesn't apply.


Stanley Challenger Graham




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Tizer
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5150 Posts
Posted - 12/03/2008 : 17:17
Research could put penicillin back in battle against antibiotic resistant bugs that kill millions
Press release from the University of Warwick (10 March 2008)

Research led by the University of Warwick has uncovered exactly how the bacterium Streptococcus pneumoniae has become resistant to the antibiotic penicillin. The same research could also open up MRSA to attack by penicillin and help create a library of designer antibiotics to use against a range of other dangerous bacteria.

Worldwide Streptococcus pneumoniae causes 5 million fatal pneumonia infections a year in children. In the US it causes 1 million cases a year of pneumococcal pneumonia in the elderly of which up to 7% are fatal. This new research has completely exposed how Streptococcus pneumoniae builds its penicillin immunity and opens up many ways to disrupt that mechanism and restore penicillin as a weapon against these bacteria.

The research was led by Dr Adrian Lloyd of the University of Warwick's Department of Biological Sciences along with other colleagues from the University of Warwick, the Université Laval, Ste-Foy in Quebec, and The Rockefeller University in New York. The research was funded by Welcome Trust and the MRC.

Penicillin normally acts by preventing the construction of an essential component of the bacterial cell wall: the Peptidoglycan. This component provides a protective mesh around the otherwise fragile bacterial cell, providing the mechanical support and stability required for the integrity and viability of cells of Streptococcus pneumoniae and other bacteria including MRSA.

The researchers targeted a protein called MurM that is essential for clinically observed penicillin resistance and has also been linked to changes in the chemical make up of the peptidoglycan that appear in penicillin resistant Streptococcus pneumoniae isolated from patients with pneumococcal infections.

The researchers found that MurM acted as an enzyme that was key to the formation of particular structures within the S. pneumoniae peptidoglycan called dipeptide bridges that link together strands of the peptidoglycan mesh that contributes to the bacterial cell wall. The presence of high levels of these dipeptide bridges in the peptidoglycan of Streptococcus pneumoniae is a pre-requisite for high level penicillin resistance.

The Warwick team were able to replicate the activity of MurM in a test tube, allowing them to define the chemistry of the MurM reaction in detail and understand every key step of how Streptococcus pneumoniae deploys MurM to gain this resistance.

The results will allow the Warwick team, and any interested pharmaceutical researchers, to target the MurM reaction in Streptococcus pneumoniae in a way which will lead to the development of drugs which will disrupt the resistance of Streptococcus pneumoniae to penicillin.

The same research also offers exciting possibilities to disrupt the antibiotic resistance of MRSA which uses similarly constructed peptide bridges in the construction of the peptidoglycan component of its cell wall. Therefore, thanks to this research, even MRSA could now be opened up to treatment by penicillin.

A further spin-off from this new MurM research, is that the Warwick led researchers are also able to readily reproduce every precursor step the bacterial cell uses to create its peptidoglycan. The tools developed at Warwick open up each step of the creation of the peptidoglycan (MurA, MurB, MurC etc, etc) used by an array of dangerous bacteria. This provides a valuable collection of targets for pharmaceutical companies seeking ways of disrupting antibiotic resistance in such bacteria.

The University of Warwick part of the research team have now established a new network of academics from the fields of chemistry, biology and medicine, as well as pharmaceutical companies to share and exploit this new treasure trove of targets which could help create a range of new designer antibiotic based treatments targeted at a range of bacteria that can cause significant health problems.

This network is the UK Bacterial Cell Wall Biosynthesis Network or UK-BaCWAN and it is supported by the Medical Research Council of the UK. The network web site is http://www.warwick.ac.uk/go/bacwan

Edited by - Tizer on 12/03/2008 17:17:58


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Stanley
Local Historian & Old Fart


36804 Posts
Posted - 12/03/2008 : 17:27
If they have it right this is brilliant news.....  How long before it translates into reality?  If it does solve a problem could it work against other efforts like having cleaner hospitals and procedures, ie. be the easiest and cheapest way out?


Stanley Challenger Graham




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Tizer
VIP Member


5150 Posts
Posted - 13/03/2008 : 15:17
I guess it has the potential to be very useful - as long as the funding is sufficient and for long enough. If it goes the way of the Animal research labs at Pirbright then perhaps not.


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Stanley
Local Historian & Old Fart


36804 Posts
Posted - 13/03/2008 : 17:27
Just been listening to R4.  Batteries that breathe and use oxygen as one of their components and holograms that can detect drugs and identify them.......  Magic.


Stanley Challenger Graham




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Tizer
VIP Member


5150 Posts
Posted - 17/03/2008 : 10:57
A press release on 16 March 2008 from the the UN Environment Programme - see also my post on European glaciers on 16 March 2008 in the OGFB Climate Change thread

Meltdown in the Mountains

Record Glacier Thinning Means No Time to Waste on Agreeing New International Climate Regime

Zurich/Nairobi, 16 March 2008 - The world's glaciers are continuing to melt away with the latest official figures showing record losses, the UN Environment Programme (UNEP) announced today.

Data from close to 30 reference glaciers in nine mountain ranges indicate that between the years 2004-2005 and 2005-2006 the average rate of melting and thinning more than doubled.

The findings come from the World Glacier Monitoring Service (WGMS), a centre based at the University of Zurich in Switzerland and that is supported by UNEP.

It has been tracking the fate of glaciers for over a century. Continuous data series of annual mass balance, expressed as thickness change, are available for 30 reference glaciers since 1980.

Prof. Dr. Wilfried Haeberli, Director of the Service said: "The latest figures are part of what appears to be an accelerating trend with no apparent end in sight".

The Service calculates thickening and thinning of glaciers in terms of 'water equivalent'. The estimates for the year 2006 indicate that further shrinking took place equal to around 1.4 metres of water equivalent compared to losses of half a metre in 2005.

"This continues the trend in accelerated ice loss during the past two and a half decades and brings the total loss since 1980 to more than 10.5 metres of water equivalent," said Professor Haberli. During 1980-1999, average loss rates had been 0.3 metres per year. Since the turn of the millennium, this rate had increased to about half a metre per year.

The record loss during these two decades - 0.7 metres in 1998 - has now been exceeded by three out of the past six years: 2003, 2004 and 2006.

On average, one metre water equivalent corresponds to 1.1 metres in ice thickness indicating a further shrinking in 2006 of 1.5 actual metres and since 1980 a total reduction in thickness of ice of just over 11.5 metres or almost 38 feet.

Achim Steiner, UN Under-Secretary General and UNEP Executive Director, said: "

"Millions if not billions of people depend directly or indirectly on these natural water storage facilities for drinking water, agriculture, industry and power generation during key parts of the year," said Mr Steiner.

"There are many canaries emerging in the climate change coal mine. The glaciers are perhaps among those making the most noise and it is absolutely essential that everyone sits up and takes notice," he said.

"To an important and significant extent that is already happening-indeed the elements of a Green Economy are already emerging from the more than $100 billion being invested in renewable energies to the responsible investment principles endorsed by 300 financial institutions with $13 trillion-worth of assets," said Mr Steiner.

"The litmus test will come in late 2009 at the climate convention meeting in Copenhagen. Here governments must agree on a decisive new emissions reduction and adaptation-focused regime. Otherwise, and like the glaciers, our room for man oeuvre and the opportunity to act may simply melt away," he added.

The WGMS findings also contain figures from around 100 glaciers, of which 30 form the core assessment, found in Antarctica, Asia, Europe, North America, Latin America and the Pacific.

Some of the most dramatic shrinking has taken place in Europe with Norway's Breidalblikkbrea glacier thinning by close to 3.1 metres (2.9 metre water equivalent) during 2006 compared with a thinning of 0.3 metres (0.28 metres water equivalent) in the year 2005.

Other dramatic shrinking has been registered at Austria's Grosser Goldbergkees glacier, 1.2 metres in 2006 versus 0.3 in 2005; France's Ossoue glacier, nearly 3 metres versus around 2.7 metres in 2005; Italy's Malavalle glacier 1.4 metres versus around 0.9 metres in 2005; Spain's Maladeta glacier, nearly 2 metres versus 1.6 metres in 2005; Sweden's Storglaciaeren glacier, 1.8 metres versus close to 0.080 metres in 2005 and Switzerland's Findelen glacier, 1.3 metres versus 0.22 metres in 2005.

Not all of the close to 100 glaciers monitored posted losses with some thickening during the same period including Chile's Echaurren Norte glacier while others, such as Bolivia's Chacaltaya glacier; Canada's Place glacier; India's Hamtah glacier and the Daniels and Yawning glaciers in the Untied States shrank less in 2006 than they did in 2005.

However, for the close to 30 reference glaciers only one (Echaurren Norte in Chile) thickened over the same period.

Notes to Editors

The latest WGMS figures can be accessed at http://www.geo.unizh.ch/wgms/mbb/mbb9/sum06.html

The potential impacts of climate change on glaciers was outlined in the fourth assessment report of the Intergovernmental Panel on Climate Change (UNEP and the World Meteorological Organisation) published in 2007.

Some highlights:-

Himalayan glaciers are receding in a similar way as glaciers in other mountain ranges at low latitudes. Many glaciers in these areas could, at current rates of global warming, disappear within the coming decades.

Half a billion people in the Himalaya-Hindu-Kush region and a quarter billion downstream who rely on glacial melt waters could be seriously affected.

The current trends in glacial melt suggest that the Ganga, Indus, Brahmaputra and other rivers that criss-cross the northern Indian plain may become seasonal rivers in the near future as a consequence of climate change with important ramifications for poverty and the economies in the region.

North America: "Heavily-utilized water systems of the western US and Canada, such as the Columbia River, that rely on capturing snowmelt runoff will be especially vulnerable," says the Fourth report of IPCC Working Group II.

A two degree C warming by the 2040s is likely to lead to sharply reduced summer flows coinciding with sharply rising demand.

The report estimates that Portland, Oregon will by then require over 26 million additional cubic meters of water as a result of climate change and population growth.

This will coincide with a fall in summer supplies from the Columbia River by an estimated five million cubic meters.

Meanwhile, just over 40 per cent of the supply to southern California is likely to be vulnerable by the 2020s due to warming triggering losses of the Sierra Nevada and Colorado River basin snow pack.

In Latin America, the IPCC warns of a melting of most tropical glaciers in the near future (2020-2030).

The glacier retreat trend reported in the Third Assessment Report of the IPCC is continuing and reaching critical conditions in Bolivia, Peru, Colombia and Ecuador.

Recent studies indicate that most of the South American glaciers from Colombia to Chile and Argentina (up to 25ºS) are drastically reducing their volume at an accelerated rate. Changes in temperature and humidity are the primary cause for the observed glacier retreat during the 2nd half of the 20th century in the tropical Andes. In the next 15 years inter-tropical glaciers are very likely to disappear, affecting water availability and hydropower generation.


Fron UNEP web site - click here

Edited by - Tizer on 17/03/2008 10:57:49


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Tizer
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Posted - 26/03/2008 : 09:54
Plants use photosynthesis to harvest the energy of sunlight efficiently. Scientsist are looking for ways to mimic photosynthesis so that we can better use solar energy, especially to split water into hydrogen and oxygen (oxidation of water).

 

Artificial Photosynthesis Moves a Step Closer - stable catalyst for water oxidation synthesised
Press release from Jülich Institute of Solid State Research, Germany (25 March 2008)

Jülich scientists have made an important step on the long road to artificially imitating photosynthesis. They were able to synthesise a stable inorganic metal oxide cluster, which enables the fast and effective oxidation of water to oxygen. This is reported by the German high-impact journal "Angewandte Chemie" in a publication rated as a VIP ("very important paper"). Artificial photosynthesis may decisively contribute to solving energy and climate problems, if researchers find a way to efficiently produce hydrogen with the aid of solar energy.

Hydrogen is regarded as the energy carrier of the future. The automobile industry, for example, is working hard to introduce fuel cell technology from approximately 2010. However, a fuel cell drive system can only be really environmentally friendly, if researchers succeed in producing hydrogen through renewable processes. Artificial photosynthesis, i.e. the splitting of water into oxygen and hydrogen with the aid of sunlight, could be an elegant way of solving this problem.

However, the road to success is littered with obstacles. One of the problems to be overcome is the formation of aggressive substances in the process of water oxidation. Plants solve this problem by constantly repairing and replacing their green catalysts. A technical imitation depends on more stable catalysts as developed and synthesised for the first time by a team from Research Centre Jülich, member of the Helmholtz Association, and from Emory University in Atlanta, USA. The new inorganic metal oxide cluster with a core consisting of four ions of the rare transition metal ruthenium catalyses the fast and effective oxidation of water to oxygen while remaining stable itself.

"Our water-soluble tetraruthenium complex displays its effects in aqueous solution already at ambient temperature," enthuses Prof. Paul Kögerler from the Jülich Institute of Solid State Research, who synthesised and characterised the promising cluster together with his colleague Dr. Bogdan Botar. Catalytic measurements were carried out at Emory University. "In contrast to other molecular catalysts for water oxidation, our catalyst does not contain any organic components. This is why it is so stable".

Botar explains the next step: "Now the challenge is to integrate this ruthenium complex into photoactive systems, which convert solar energy into chemical energy". So far, energy is still obtained from a chemical oxidant.

Original publication:
Yurii V. Geletii, Bogdan Botar, Paul Kögerler, Daniel A. Hillesheim, Djamaladdin G. Musaev, and Craig L. Hill;
An All-Inorganic, Stable, and Highly Active Tetraruthenium Homogeneous Catalyst for Water Oxidation;
Angewandte Chemie, DOI: 10.1002/ange.200705652.


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Tizer
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Posted - 26/03/2008 : 09:58
Substantial improvement in essential cheap solar cell process
Press release from Delft University of Technology, The Netherlands (20 March 2008)

A cheap alternative to silicon solar cells can be found in dye-sensitised solar cells. This type of cell imitates the natural conversion of sunlight into energy by, for instance, plants and light-sensitive bacteria. Annemarie Huijser has succeeded in substantially improving a process in this type of solar cell, which is similar to Grätzel cells. Huijser received her PhD on this subject from TU Delft on Tuesday 25 March.

The use of solar cells is increasing very slowly. One of the reasons is that the most commonly used type, made from silicon, is quite expensive to manufacture. That is why there has been a great deal of research into alternative solar cells over the past few years. In searching for solutions, scientists are inspired by nature. Plants are able to transport absorbed solar energy over long distances, typically about 15-20 nanometres, to a location in which it is converted into chemical energy. This is because the chlorophyll molecules in their leaves are arranged in the best possible sequence. During her PhD, Annemarie Huijser attempted a partial recreation in solar cells of this process as found in plants. She focused on what are known as dye-sensitised solar cells. These comprise a semiconductor, such as titanium dioxide, covered with a layer of dye. The dye absorbs energy from sunlight, which creates what are known as excitons. These energy parcels then need to move towards to the semiconductor. Once there, they generate electric power.

Huijser: "You can compare dye molecules to Lego bricks. I vary the way the bricks are stacked and observe how this influences the exciton transport through the solar cells. Excitons need to move as freely as possible through the solar cells in order to generate electricity efficiently."
By studying the best sequence of dye molecules, Huijser succeeded in increasing the average distance which the excitons move in the solar cell by twenty times up to a distance of approximately 20 nanometres, comparable to systems found in nature. This substantially increases the efficiency of the cells.

In order to make this new type of solar cell commercially viable, Huijser estimates that the mobility of the excitons needs to increase further by a factor of three. She believes that this is certainly possible. ‘Once that has been achieved, there is nothing to stop this type of solar cell being developed further.'

The solar cells used by Huijser are closely related to the more widely known Grätzel cells. In the case of Grätzel cells, however, the dye and semiconductor are very close to each other, they are almost blended. As a result, the excitons do not need to move that far. One disadvantage of this type of cell, however, is the complicated method of charge transport. For this reason, Huijser chose to adopt a different approach and use this simple dual-layer system of dye and semiconductor.

Edited by - Tizer on 26/03/2008 09:59:07


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