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(Nanowerk News) Researchers from North Carolina State University and Purdue University have shown that the semiconductor material gallium nitride (GaN) is non-toxic and is compatible with human cells – opening the door to the material’s use in a variety of biomedical implant technologies.
GaN is currently used in a host of technologies, from LED lighting to optic sensors, but it is not in widespread use in biomedical implants. However, the new findings from NC State and Purdue mean that GaN holds promise for an array of implantable technologies – from electrodes used in neurostimulation therapies for Alzheimer’s to transistors used to monitor blood chemistry.
“The first finding is that GaN, unlike other semiconductor materials that have been considered for biomedical implants, is not toxic. That minimizes risk to both the environment and to patients,” says Dr. Albena Ivanisevic, who co-authored a paper describing the research (“Gallium Nitride is Biocompatible and Non-Toxic Before and After Functionalization with Peptides”). Ivanisevic is an associate professor of materials science and engineering at NC State and associate professor of the joint biomedical engineering program at NC State and the University of North Carolina at Chapel Hill.
Researchers used a mass spectrometry technique to see how much gallium is released from GaN when the material is exposed to various environments that mimic conditions in the human body. This is important because gallium oxides are toxic. But the researchers found that GaN is very stable in these environments – releasing such a tiny amount of gallium that it is non-toxic.
The researchers also wanted to determine GaN’s potential biocompatibility. To do this they bonded peptides – the building blocks that make up proteins – to the GaN material. Researchers then placed peptide-coated GaN and uncoated GaN into cell cultures to see how the material and the cells interacted.
Researchers found that the peptide-coated GaN bonded more effectively with the cells. Specifically, more cells bonded to the material and those cells spread over a larger area.
“This matters because we want materials that give us some control over cell behavior,” Ivanisevic says. “For example, being able to make cells adhere to a material or to avoid it.
“One problem facing many biomedical implants, such as sensors, is that they can become coated with biological material in the body. We’ve shown that we can coat GaN with peptides that attract and bond with cells. That suggests that we may also be able to coat GaN with peptides that would help prevent cell growth – and keep the implant ‘clean.’ Our next step will be to explore the use of such ‘anti-fouling’ peptides with GaN.”
Source: By Matt Shipman, North Carolina State University
China, as the world’s largest steel producer, is the world’s largest consumer of molybdenum. China is also the world’s largest moly-producing country (although North America is the largest producing region). According to the International Molybdenum Association, use of molybdenum in transportation, power generation, building and construction will likely increase by 6 percent each year through 2019. This view was shared by Roskill last year, who saw under-investment in molybdenum projects in 2009 and 2010 having consequences for supply as far ahead as 2015. So if demand is strong and supply is constrained, why have prices fallen this year, and could the predicted long-term price / demand trend be at risk?
Iron ore demand and steel production in the world’s largest steel market, China, have remained strong this year, yet molybdenum imports have not kept pace. As an article in the Tex Report states, the Chinese Iron and Steel Association (CISA) released data showing that steel production in September was up 3.1 percent from August.
The total annualized run rate of production is over 700 million tons, compared year-over-year with 2010, when China produced just over 550 million tons. The global steel production growth rate stands at 9.8 percent, although recent numbers suggest a distinct softening everywhere except Asia. China, however, has been pushing 13.8 percent this year. The continued strength of steel production in China would suggest that molybdenum, an essential in high-strength steel production, would also be equally well supported. But as the table below shows, China has swung to becoming a net exporter of moly oxide.
Although June and July saw imports exceed exports as domestic mines in China are brought on-stream, it is expected that China will increasingly seek to rely on domestic molybdenum concentrate supply rather than imports, resulting in ongoing pressure on prices. Molybdenum has fallen to below $14/lb, and unless Chinese merchants decide to step back into the market to opportunistically import, global demand is likely to remain bereft of Chinese buying.
While domestic prices have followed the global trend in broad terms, this graph of ferro-moly prices in China taken from the MetalMiner IndX shows they have not been as volatile:
With slowing demand in China inevitably feeding through into slowing steel growth, the chances of China resuming imports on a consistent basis looks unlikely. Good news for moly consumers in the West, who were harboring concerns earlier that supply constraints would prompt a return to higher prices next year.
by Stuart Burns
The following is a guest post by Lawrence Carrel, author of “ETFs for the Long Run” and “Dividend Stocks for Dummies.” The opinions expressed are his own. Full disclosure: The author has had 7 percent of his personal retirement account in a gold ETF for the past four years.
When the price of gold plunged 20 percent last month, many market watchers declared the gold boom over. Stalled, yes; ended, no, according to many gold analysts, who believe the precious metal may instead be near a new sustained rally.
“I can tell investors don’t sell off your gold,” says Martin Murenbeeld, the chief economist at DundeeWealth. “We’re at a crossroads here.”
During the summer, gold surged 29 percent to a record high of $1,920 a troy ounce. This jump caused the price to drastically detach from its 200-day moving average, an important trend line in technical analysis that the gold price had closely hugged for much of the last decade. Technical analysts considered this jump unsustainable and in September gold gave back most of these gains.
Gold fell to a low of $1,534.49, much to the technicians delight, and it bounced off the 200-day moving average’s support level of $1,527. While most gold watchers expect the metal to experience turbulence during the next few months, the world hasn’t changed much, and gold prices may climb higher because of its status as a safe-haven during turbulent times.
“Have the countries around the world solved the debt crisis?” asks Nick Barisheff, president of Bullion Management Group, a precious metals investment company based in Toronto. “Have the bailouts ended? Have their currencies stopped tanking?“ With the world already worried about Greece’s fiscal problems, gold summer’s rally was sparked by fears that the U.S. might default on its debt.
After Standard & Poor’s downgraded the U.S. debt, investors flocked to gold as one of the few safe havens left. This raised the specter of recession, which is never good for gold. The combination of increased collateral requirements for trading with falling commodity and stock markets, gold tumbled as investors sold it for liquidity amidst a flurry of margin calls.
Still many analysts think the gold market isn’t in a bubble and that the run-up is far from over. Analysts say a bubble is when an asset goes up exponentially 15 to 20 times.
Gold is up seven times during the last decade. Since its low on Sept.26, 2011, gold has jumped 9 percent. Most analysts expect the price to retest September’s low during the next few months. If it bounces again that would be the buy signal.
Ed Carlson, Chief Market Technician at Seattle Technical Advisors.com says gold could fall as far at $1,460. But even Carlson predicts a new sustained advance will begin after Thanksgiving.
The fundamental factors for being bullish are also compelling. Low interest rates are very good for gold. In August, the Federal Reserve promised to keep rates low for the next two years. Additionally, most analysts expect the European Central Bank (ECB) to stem the European debt crisis with a flood of new money.
“The relationship between gold and world liquidity is very direct,” says Murenbeeld. “If countries print money gold goes up.” Murenbeeld says there is a high probability that the ECB and the European System of Financial Supervisors (ESFS) will insert a significant amount of money into the system, anywhere from 1 trillion euros to 2 trillion euros.
“This liquidity will stabilize the banking sector so that it can withstand a default from Greece and speculation of default from other countries. All that plays into the hands of gold.” Murenbeeld recommends investors use a dollar cost averaging strategy here. “When they do the bailout that will dilute the currency, “ says Barisheff.
“The governments will be forced to print more money because politically that’s the least painful thing to do. And as they do the price of gold goes up.”
However, Barisheff warns that it’s easy for governments to lose control of their currency, which can send a country into hyperinflation. He says gold will stop rising when governments institute sustainable economic policies, but if inflation isn’t controlled, gold could rise as high as $10,000 in five years. “And there is no appetite to do anything sustainable.”
An end product’s supply chain can be far reaching, with parts or all of the upstream and downstream producers sometimes getting hit at different times by economic forces.
This appears to be happening in China’s domestic LED market, which has seen a marked fall-off in demand, according to the China Strategic Monitor. That’s hit pricing during the second half of this year.
“Investment plans are being curtailed both in the upstream and downstream compared to those presented last year,” according to the report. “Despite this there are many companies still attracted to the market and many pharmaceutical companies and even wineries in South China are moving into LED lighting products. Based on this trend the industry is likely to realize large-scale production capacity over the next 2 or 3 years and pricing for products should fall a further 20-30%.”
Industry watchers reckon 10% of LED-driven businesses in China could go bankrupt this year. And one chief executive, speaking at the recent China Industrial Development Forum for the Low Carbon Economy, said 90% of all China’s LED businesses are running at a loss.
Interesting. The country’s Guangdong province said earlier this month that it had exported US$3.81 billion worth of lighting products between January and August – that’s a 21% increase over the same time period last year.
“Customs authorities indicated that the main export market is still Europe and America with the two taking up 63.2% of the total,” a report said. “Though exports to Hong Kong, Japan and other ASEAN countries are up 60% on last year.”
The massive rise in LED exports is ascribed to the increasing trend of upgrading to energy-efficient lighting combined with the higher production values and quality in China, according to the report.
Still, various companies producing LED products complain that the industry is hit with high selling, raw material and R&D costs. So, while a company reports a 32% jump in LED sales in the third quarter of 2011when compared to 2Q10, the senior executives also talk about the need to implement structural changes, improve execution, reduce overhead costs and initiate job cuts.
Now, the LED industry uses a wide range of phosphor materials to convert light emission from LED chips into a different wavelength. So, combining a blue LED with one or more phosphors can create a white LED. Many of the phosphors used in LEDs contain rare-earth elements, the most common one being the yttrium aluminum garnet, which is doped with cerium. Another phosphor, called TAG, contains terbium, while silicate and nitride phosphors are commonly doped with cerium or europium.
Here’s a small example of how LED products are being used: Kingsun Optoelectronic Co has just installed more than 10,000 street lights containing one million high-efficiency white LEDs along 75 miles of roads in Shenzhen. Kingsun anticipates a 60-percent reduction in energy consumption compared to the high-pressure sodium fixtures that have been replaced in the upgrade.
And while LEDs are now widely recognized as emerging light sources for general illumination, it turns out that LED lighting can also be used in a broad range of life-science applications such as skin-related therapies, blood irradiation, pain management, hypertension reduction and photodynamic therapy, which, when combined with drugs, is finding its way into cancer research.
In other words, the LED industry is only now just starting to be exploited, meaning demand will grow across all sectors. Translation – more rare earths will be needed in producing these products as research advances are made and commercial producers become more lean and efficient.
By: Brian Truscott
China’s largest rare earths producer, Baotou, has suspended production for one month in an effort to prop up falling prices, in the clearest signal yet that Chinese producers are intent on supporting prices at high levels.
China is the world’s biggest producer of rare earths, but tightening government controls and stockpiling has sent rare earths prices rocketing this year, with prices for some minerals increasing more than eight times during the first half of the year.
Rare earths prices have been sliding since their peak in July, but the slide has accelerated during the past week. Neodymium, which is used in magnets, has fallen 9 per cent, while Lanthanum, which is used in fuel catalytic converters, has fallen 12 per cent, according to prices from Shanghai Metals Market.
Baotou’s move suggests that Chinese efforts to control rare earths prices could be greater than previously thought. Traders have complained since last year that Chinese customs officials were forcing contracts to be rewritten to conform with a “secret list” of acceptably high rare earths prices, but that had less influence on the market during a time when prices were uniformly going up.
Rare earths are 17 metals critical to everyday life, with uses that range from fluorescent lightbulbs to BlackBerry vibrators and military radar systems. Although rare earths are not technically rare, China produces more than 95 per cent of the world’s rare earths, after cheap Chinese mines sent other rare-earths miners out of business during the 1980s.
After cutting export quotas last year, Beijing has this year focused on cleaning up the rare earths industry at the source, closing illegal mines and processing centres that were previously sources of pollution. Those in the industry believe that the rare earths reforms have also been aimed at increasing state control over the previously fragmented sector. In May, the government announced that three state-owned groups would take the lead in reshaping the industry in the fragmented southern sector.
Baotou, which controls about 40 per cent of China’s rare earths production through mines in Inner Mongolia, said on Tuesday that it was suspending operations at all of its rare earths processing facilities in a bid to “stabilise the market and balance supply and demand”.
It is the second time in recent weeks that Baotou has tried to prop up prices, after very publicly purchasing neodymium at above-market prices last month. Baotou said the suspension, which begins on Wednesday, would also cut supplies of unprocessed rare earths to processing plants that buy from Baotou.
Shanghai share prices for Baotou fell 5.8 per cent on Tuesday, against a broader market decline of 2.4 per cent.
October 18, 2011
By Leslie Hook in Beijing
Researchers using novel materials to build photovoltaic cells say their efforts could nearly double the efficiency of silicon-based solar cells.
The cells being developed by teams from the University of Arkansas and Arkansas State University have the potential to achieve a light-to-energy conversion rate, or solar efficiency, of 40 percent or better, according to the researchers.
The photovoltaic cells are intended for use in satellites and space instruments. Currently, the silicon-based solar cells that NASA uses in its satellites and instruments have efficiencies of only up to 23 percent, according to NASA statistics.
And today it was announced that the research teams are getting more money–a total of $1 million in new funding–to further their work. Of that, about $735,000 will come from NASA, $237,000 from the University of Arkansas, and $86,000 from Arkansas State.
Omar Manasreh, professor of electrical engineering at the Optoelectronics Research Lab at the University of Arkansas, has been developing the technology so far with a $1.3 million grant from the U.S. Air Force Office of Scientific Research. He leads the research team along with Liangmin Zhang, assistant professor at Arkansas State.
“It [the grant] will create new opportunities for further development in the field of novel photovoltaic materials and devices,” Manasreh said in a statement.
Manasreh has been testing two separate methods for growing metallic nanoparticles using a novel combination of materials as the semiconductor. While CIGS (copper, indium, gallium and selenium) solar cells are not uncommon, Manasreh is using a variation of CIGS-based cells–CuInSe2 and CuInGaSe2–to generate molecules that bind to a central atom and that are known as volatile ligands. The nanocrystals can then be converted into thin-film solar cells, or incorporated into nanotubes, by combining the material with either titanium dioxide or zinc oxide. His second approach uses indium arsenide (InAs) a material commonly used in infrared detectors.
“The second approach uses molecular beam epitaxy, a method of depositing nanocrystals, to create quantum dots made of indium arsenide (InAs). Quantum dots are nano-sized particles of semiconductor material,” according to the University of Arkansas.
When exposed to ultraviolet light, the nanocrystals grown in liquid emit brighter light enhancing the response of the nanocrystals. The phenomenon shows the potential to increase the energy conversion efficiency of the materials (see photo).
This research team isn’t the first to experiment with growing nanoparticles using liquid. In 2007, Calif-based company Innovalight developed a “silicon ink” for creating crystalline silicon solar cells that works by inserting nanoparticles into a solvent, pouring the liquid on a substrate, and then removing the liquid to be left with a silicon crystalline structure. At the time, the solar cells made from the method had a 22 percent efficiency. Innovalight was acquired by Dupont earlier this year.