SAN FRANCISCO--Samsung touted its new 32-nm high-k metal gate (HKMG) process at the International Solid-State Circuits Conference here Tuesday (Feb. 21), showing features it hopes might win customers over from a supply constrained TSMC.
While ostensibly presenting its upcoming 32-nm quad-core mobile processor, Samsung spent much of the time presenting its new process, which as well as boasting HKMG, also uses dynamic thermal management and body bias techniques, for a significant 40 percent performance increase over its 45-nm Exynos chip.
Intel and Globalfoundries have been shipping chips with HKMG for a while now, but with Samsung and TSMC joining the fray, the fab playing field is somewhat equalized.
With the industry bracing itself for a tight supply of 28-nm from TSMC, Samsung’s 32-nm process and excess capacity manufacturing facilities could prove an attractive alternative to the likes of Nvidia, or even AMD.
Analysts believe TSMC would give priority to customers like Apple or Qualcomm for the 28-nm process, which would make it difficult for smaller players to get the supply they needed. Samsung is not supply constrained, and the difference between a 28-nm process and a 32-nm process using HKMG is fairly marginal in terms of the end result.
On the other hand, some in the industry still have qualms over using Samsung as a foundry, largely because the firm competes with almost every one of its potential customers.
Samsung's chip-building capabilities were being put under the microscope on Tuesday, with the firm also talking up its dynamic thermal management system for mobile SoCs, as well as power gate technology for every CPU and even inside the GPU, allowing power to be switched off, cutting leakage at the source.
Body Biasing, too, would give Samsung a differentiating factor from the likes of Intel, which doesn’t use the technology. Body Biasing can be used to either speed up a transistor when full throttle is needed, increasing leakiness slightly, or it can slow the transistor down, stemming leakage for a more optimal low power state.
Whether customers will be enticed, however, remains to be seen.
Samsung positions its fab to take on TSMC
TAG:samsung chips tsmc fab
2012-02-22
Injectable gel could repair tissue damaged by heart attack
The study by Karen Christman and colleagues appears in the Feb. 21 issue of the Journal of the American College of Cardiology. Christman is a professor in the Department of Bioengineering at the UC San Diego Jacobs School of Engineering and has co-founded a company, Ventrix, Inc., to bring the gel to clinical trials within the next year.
Therapies like the hydrogel would be a welcome development, Christman explained, since there are an estimated 785,000 new heart attack cases in the United States each year, with no established treatment for repairing the resulting damage to cardiac tissue.
The hydrogel is made from cardiac connective tissue that is stripped of heart muscle cells through a cleansing process, freeze-dried and milled into powder form, and then liquefied into a fluid that can be easily injected into the heart. Once it hits body temperature, the liquid turns into a semi-solid, porous gel that encourages cells to repopulate areas of damaged cardiac tissue and to preserve heart function, according to Christman. The hydrogel forms a scaffold to repair the tissue and possibly provides biochemical signals that prevent further deterioration in the surrounding tissues.
"It helps to promote a positive remodeling-type response, not a pro-inflammatory one in the damaged heart," Christman said.
What's more, the researchers' experiments show that the gel also can be injected through a catheter, a method that is minimally invasive and does not require surgery or general anesthesia.
New, unpublished work by her research team suggests that the gel can improve heart function in pigs with cardiac damage, which brings this potential therapy one step closer to humans, said Christman.
There are few injectable cardiac therapies in development designed to be used in large animals such as pigs, which have a heart that is similar in size and anatomy to the human heart, Christman explained. "Most of the materials that people have looked at have been tested in rats or mice, and they are injectable via a needle and syringe. However, almost all of them are not compatible with catheter delivery and would gel too quickly, clogging the catheter during the procedure.
In experiments with rats, the gel was not rejected by the body and did not trigger arrhythmic heart beating, providing some assurance that the gel will be similarly safe for humans, the researchers note.
Christman has an equity interest in Ventrix, Inc., a company that may potentially benefit from the research results, and also serves on the company's Scientific Advisory Board. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict of interest policies.
The study's co-authors include Jennifer Singelyn, Priya Sundaramurthy, Todd Johnson, Pamela Schup-Magoffin, Diane Hu, Denver Faulk, Jean Wang, and Kristine M. Mayle in the Department of Bioengineering; Kendra Bartels, Anthony N. DeMaria, and Nabil Dib of the UC San Diego School of Medicine; and Michael Salvatore and Adam M. Kinsey of Ventrix, Inc. The research was funded in part by the National Institutes of Health Director's New Innovator Award Program (part of the NIH Roadmap for Medical Research), the Wallace H. Coulter Foundation, and the National Science Foundation.
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Caught in the act: Scientists discover microbes speciating
The idea of sympatric speciation (one lineage diverging into two or more species with no physical or mechanical barriers keeping them apart) is controversial and tricky to prove, especially in microbes, said University of Illinois microbiology professor Rachel Whitaker, who led the study.
"One of the big questions, from Darwin on, is how do species diverge if they are living together?" she said. "That question really hasn't been answered very well, even in the macro-organisms that we've studied for hundreds of years."
Bacteria and their distantly related microbial cousins the archaea (are-KEY-uh) are even more difficult to study because they have so many ways to share genetic information, Whitaker said. The microbes divide to conquer, producing exact or near-exact clones of themselves. If this were their only way of getting established, their genetic diversity would be quite low, the result of a few random copy errors and mutations, Whitaker said. But they also can link up with each other to pass genes back and forth, suck up random genetic elements from the environment and acquire new genes from the viruses that infect them and their neighbors.
Before scientists were able to dissect the genetic endowment of individual microbes, they had a hard time telling the bugs apart -- so much so that they once confused bacteria and archaea. Researchers now know that the archaea belong to third domain of life -- as different from bacteria as plants and animals are.
"Every time we look, everywhere we look we see variation in microbial populations using these molecular tools," Whitaker said. "You have to use these molecules, these DNA sequences, to tell the difference between species." But even with new sequencing technologies, the task of studying microbial evolution is daunting.
Whitaker and her colleagues focused on Sulfolobus islandicus, a heat-loving organism from the archaeal domain of life, because it is one of few microorganisms that live in distinct "island" populations created by geothermal hot springs. (Watch a movie of a hot spring in Yellowstone Park that is similar to the one the scientists sampled.)
"We're looking at an environment that's not very complex in microbial terms," Whitaker said. "There are not that many organisms that can handle it, and the ones that can don't successfully move around very often."
The researchers sequenced the genomes of 12 strains of S. islandicus from a single hot spring in the Mutnovsky Volcano region of Kamchatka. By comparing sequences at multiple sites on the microbes' single (circular) chromosome using new software programs ClonalFrame and ClonalOrigin, the researchers were able to reconstruct the genetic history of each of the strains.
The analysis revealed two distinct groups of S. islandicus among the 12 strains. The microbes were swapping genes with members of their own group more than expected, but sharing genes with the other group less than expected, Whitaker said. And the exchange of genetic material between the two groups was decreasing over time.
This indicates that the two groups are already separate species, even though they share the same habitat, Whitaker said. The differences between the two groups were slight, but speciation was clearly under way, she said.
Peering more closely at the patterns of change, the researchers saw a mosaic of differences along the chromosome, with vast "continents" of variation and smaller "islands" of stability. Those islands likely represent regions that are under selective pressure, Whitaker said; something in their environment is weeding out the microbes that don't have those genes or sets of genes. The variable regions are more fluid, with genes coming and going (a process called recombination) and mutations increasing diversity.
The findings provide the first evidence that sympatric speciation occurs in a microbe, Whitaker said.
"We caught them speciating," she said. "They do exchange some genes -- just not very many. So now we know you don't have to have a (geographic or mechanical) barrier to recombination for speciation to occur. All you have to have is selection pulling the two groups apart, which nobody knew before."
This study provides a glimpse of the profound genetic diversity that likely occurs everywhere in wild microbial populations, Whitaker said.
"What we see as two different species are 0.35 percent different across the chromosome; that's about one-third of the distance between human and chimp," she said. The two distinct groups of microbes are "orders of magnitude" more similar to each other than groups normally considered separate species, she said.
"That means there are orders of magnitude more species of microbes than we ever thought there were," she said. "And that's kind of mind-boggling."
The study appears in the journal PLoS Biology. The research team included scientists from Arizona State University, the University of California at Davis, and the University of Oxford.
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Wireless will redefine the home audio market as we know it
Over the next five years, wireless connectivity to mobile devices and the Internet will redefine the mainstream products within the home audio market. Despite differences in capabilities, form factors, and usage scenarios, a variety of home audio products will all increasingly incorporate wireless functionality in order to play audio streamed from mobile devices, home networks, and the Internet.
In recent years the home audio industry has been challenged to adapt to changing trends in consumers' media consumption habits and the proliferation of Internet-based streaming audio services. As a result, consumer home audio is rapidly evolving by integrating wireless connectivity into devices such as A/V receivers, soundbars, standalone speaker docks, and home theater in a box (HTIB) systems.
The soundbar and speaker dock categories have seen growth thanks to consumers trending towards mobile devices, streaming services, and less-expensive intermediate audio solutions, driven by current economic conditions. This is in large part to address the lackluster audio of thin-bezel HDTVs. Though these same trends have challenged the market for traditional A/V receivers and HTIBs, the inclusion of wireless connectivity is expected to aid both product categories going forward.
According to the IMS Research report, "A/V Receivers and Advanced Home Audio – 2012 Edition," in 2016 over 60 million audio devices will ship with WiFi and/or Bluetooth connectivity, including AV receivers, speaker docks, HTIB systems, and soundbars. Indicative of trends taking place in the consumer marketplace, the majority of this volume will be driven by speaker docks and soundbars.
According to IMS Research, as wireless home networking increases along with consumer expectations of wireless connectivity in consumer electronics, the use of wireless streaming in audio playback is expected to naturally rise on a complementary basis. Though connectivity to mobile devices is expected to be a major driver, the growing popularity of services such as Spotify, Deezer, Pandora, iCloud, and Google Music drives the need for direct Internet connectivity in some of these home audio products as well.
In the opinion of Paul Erickson, senior analyst at IMS Research, "With the move towards smartphone- and tablet-centric media consumption, and the proliferation of Internet-based music services, the home audio market is gradually adapting to meet the needs of consumers. We're clearly headed for a future where various forms of wireless streaming will be cornerstones of the audio experience in the home."
http://imsresearch.com.
This article originally appeared on EE Times Europe.
Wireless will redefine the home audio market as we know it
TAG:Wireless audio streaming audio home audio audio networking home networking Pandora iCloud Google Music
Step forward in effort to regenerate damaged nerves
It's scenes like this that neurosurgeon Jason Huang, M.D., confronts every day. Severe damage to nerves is one of the most challenging wounds to treat for Huang and colleagues. It's a type of wound suffered by people who are the victims of gunshots or stabbings, by those who have been involved in car accidents -- or by soldiers injured on the battlefield, like those whom Huang treated in Iraq.
Now, back in his university laboratory, Huang and his team have taken a step forward toward the goal of repairing nerves in such patients more effectively. In a paper published in the journal PLoS ONE, Huang and colleagues at the University of Rochester Medical Center report that a surprising set of cells may hold potential for nerve transplants.
In a study in rats, Huang's group found that dorsal root ganglion neurons, or DRG cells, help create thick, healthy nerves, without provoking unwanted attention from the immune system.
The finding is one step toward better treatment for the more than 350,000 patients each year in the United States who have serious injuries to their peripheral nerves. Huang's laboratory is one of a handful developing new technologies to treat such wounds.
"These are very serious injuries, and patients really suffer, many for a very long time," said Huang, associate professor of Neurosurgery and chief of Neurosurgery at Highland Hospital, an affiliate of the University of Rochester Medical Center. "There are a variety of options, but none of them is ideal.
"Our long-term goal is to grow living nerves in the laboratory, then transplant them into patients and cut down the amount of time it takes for those nerves to work," added Huang, whose project was funded by the National Institute of Neurological Disorders and Stroke and by the University of Rochester Medical Center.
For a damaged nerve to repair itself, the two disconnected but healthy portions of the nerve must somehow find each other through a maze of tissue and connect together. This happens naturally for a very small wound -- much like our skin grows back over a small cut -- but for some nerve injuries, the gap is simply too large, and the nerve won't grow back without intervention.
For surgeons like Huang, the preferred option is to transplant nerve tissue from elsewhere in the patient's own body -- for instance, a section of a nerve in the leg -- into the wounded area. The transplanted nerve serves as scaffolding, a guide of sorts for a new nerve to grow and bridge the gap. Since the tissue comes from the patient, the body accepts the new nerve and doesn't attack it.
But for many patients, this treatment isn't an option. They might have severe wounds to other parts of the body, so that extra nerve tissue isn't available. Alternatives can include a nerve transplant from a cadaver or an animal, but those bring other challenges, such as the lifelong need for powerful immunosuppressant drugs, and are rarely used.
One technology used by Huang and other neurosurgeons is the NeuraGen Nerve Guide, a hollow, absorbable collagen tube through which nerve fibers can grow and find each other. The technology is often used to repair nerve damage over short distances less than half an inch long.
In the PLoS One study, Huang's team compared several methods to try to bridge a nerve gap of about half an inch in rats. The team transplanted nerve cells from a different type of rat into the wound site and compared results when the NeuraGen technology was was used alone or when it was paired with DRG cells or with other cells known as Schwann cells.
After four months, the team found that the tubes equipped with either DRG or Schwann cells helped bring about healthier nerves. In addition, the DRG cells provoked less unwanted attention from the immune system than the Schwann cells, which attracted twice as many macrophages and more of the immune compound interferon gamma.
While both Schwann and DRG cells are known players in nerve regeneration, Schwann cells have been considered more often as potential partners in the nerve transplantation process, even though they pose considerable challenges because of the immune system's response to them.
"The conventional wisdom has been that Schwann cells play a critical role in the regenerative process," said Huang, who is a scientist in the Center for Neural Development and Disease. "While we know this is true, we have shown that DRG cells can play an important role also. We think DRG cells could be a rich resource for nerve regeneration."
In a related line of research, Huang along with colleagues in the laboratory of Douglas H. Smith, M.D. , at the University of Pennsylvania are creating DRG cells in the laboratory by stretching them, which coaxes them to grow about one inch every three weeks. The idea is to grow nerves several inches long in the laboratory, then transplant them into the patient, instead of waiting months after surgery for the nerve endings to travel that distance within the patient to ultimately hook up.
The first author of the PLoS One paper is research associate Weimin Liu, Ph.D. Other authors, in addition to Huang and Smith, are graduate students Yi Ren and Xiaowei Wang; post-doctoral associate Samantha Dayawansa, Ph.D.; undergraduate Adam Bossert; neurologist Handy Gelbard, M.D., Ph.D.; Jing Tong, M.D., formerly of the Huang laboratory and now a neurosurgeon at Hebei Medical University in China, and Xiaoshen He, M.D., a neurosurgeon at Fourth Military Medical University in China.
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Samsung gives peak at quad-core mobile CPU
SAN FRANCISCO – Samsung gave an early peak at its first quad-core mobile application processor at the International Solid-State Circuits Conference here. The unannounced chip is Samsung’s first to use a 32 nm high-k metal gate process and sports advances in performance and battery life over its existing 45 nm Exynos chips.
The new chip comes in versions using two or four ARM Cortex A9 cores running at rates from 200 MHz to 1.5 GHz along with a 64-bit ARM Neon media processing block. The cores share a 1 Mbyte L2 cache with a snoop control unit.
Samsung designed its own graphics unit for the chip. It includes four pixel processors and one geometry engine with a dedicated 128 KByte L2 cache. The graphics support the OpenGL ES 2.0 API and can generate up to 57 Mpolygons/s.
The chip supports two LPDDR2 or DDR3 interfaces running up to 400 MHz for a total memory bandwidth of up to 6.4 Gbytes/s.
Thanks both to the 32 nm process and a handful of power and thermal management techniques, the chip can deliver up to 26 percent more performance overall than Samsung’s current Exynos chip made in a 45 nm polysilicon process. It also can deliver improvements in battery life ranging from 34 to 50 percent, depending on the application.
Samsung said the new chip delivers up to 26.3 percent improvements in video frame rates. In a demo, Samsung showed the chip using 48 percent less power on 3-D calculations and 45 percent less power in CPU jobs than the 45 nm chip.
The 32 nm HKMG process keep transistor and gate leakage nearly to the levels of the company’s 45 nm polysilicon process, much lower than expected for 32 nm polysilicon technology. Samsung tuned the process to a sweet spot somewhere between its potential for delivering 40 percent more performance or a tenth the leakage, said Se-Hyung Yang, a principal engineer for SoC development at Samsung Electronics who presented the paper.
The chip has four independent power domains and several power sub-domains. Each ARM core and up to a half of the cache memory can be turned off or on independently. A set of media accelerator blocks are similarly power gated independently.
The chip dynamically uses either forward or reverse body-biasing on n-wells to improve performance or reduce leakage as needed. It also uses thermal monitors and a thermal management unit to trigger power management actions including shutting down blocks as needed to protect devices from over-heating and keep a handset below a fixed surface temperature set by handset makers.
“Recently power consumption for mobile devices have increased a lot and mobile devices have limited cooling capability,” said Yang, underlining a growing problem in smartphone design.
Samsung will formally announce the product soon, said Yang, presumably at next week’s Mobile World Congress. Nvidia grabbed the lead in rolling out a quad-core mobile chip last year.
Samsung gives peak at quad-core mobile CPU
TAG:Mobile Applications Processors Mobile Processors Samsung Exynos Mobile Processors Nvidia ISSCC
The new chip comes in versions using two or four ARM Cortex A9 cores running at rates from 200 MHz to 1.5 GHz along with a 64-bit ARM Neon media processing block. The cores share a 1 Mbyte L2 cache with a snoop control unit.
Samsung designed its own graphics unit for the chip. It includes four pixel processors and one geometry engine with a dedicated 128 KByte L2 cache. The graphics support the OpenGL ES 2.0 API and can generate up to 57 Mpolygons/s.
The chip supports two LPDDR2 or DDR3 interfaces running up to 400 MHz for a total memory bandwidth of up to 6.4 Gbytes/s.
Thanks both to the 32 nm process and a handful of power and thermal management techniques, the chip can deliver up to 26 percent more performance overall than Samsung’s current Exynos chip made in a 45 nm polysilicon process. It also can deliver improvements in battery life ranging from 34 to 50 percent, depending on the application.
Samsung said the new chip delivers up to 26.3 percent improvements in video frame rates. In a demo, Samsung showed the chip using 48 percent less power on 3-D calculations and 45 percent less power in CPU jobs than the 45 nm chip.
The 32 nm HKMG process keep transistor and gate leakage nearly to the levels of the company’s 45 nm polysilicon process, much lower than expected for 32 nm polysilicon technology. Samsung tuned the process to a sweet spot somewhere between its potential for delivering 40 percent more performance or a tenth the leakage, said Se-Hyung Yang, a principal engineer for SoC development at Samsung Electronics who presented the paper.
The chip has four independent power domains and several power sub-domains. Each ARM core and up to a half of the cache memory can be turned off or on independently. A set of media accelerator blocks are similarly power gated independently.
The chip dynamically uses either forward or reverse body-biasing on n-wells to improve performance or reduce leakage as needed. It also uses thermal monitors and a thermal management unit to trigger power management actions including shutting down blocks as needed to protect devices from over-heating and keep a handset below a fixed surface temperature set by handset makers.
“Recently power consumption for mobile devices have increased a lot and mobile devices have limited cooling capability,” said Yang, underlining a growing problem in smartphone design.
Samsung will formally announce the product soon, said Yang, presumably at next week’s Mobile World Congress. Nvidia grabbed the lead in rolling out a quad-core mobile chip last year.
Samsung gives peak at quad-core mobile CPU
TAG:Mobile Applications Processors Mobile Processors Samsung Exynos Mobile Processors Nvidia ISSCC
Rare element, tellurium, detected for the first time in ancient stars
Today, stars and planetary bodies bear traces of these elements, having formed from the gas enriched by these supernovas over time. For the past 50 years, scientists have been analyzing stars of various ages, looking to chart the evolution of chemical elements in the universe and to identify the astrophysical phenomena that created them.
Now a team of researchers from institutions including MIT has detected the element tellurium for the first time in three ancient stars. The researchers found traces of this brittle, semiconducting element -- which is very rare on Earth -- in stars that are nearly 12 billion years old. The finding supports the theory that tellurium, along with even heavier elements in the periodic table, likely originated from a very rare type of supernova during a rapid process of nuclear fusion. The researchers published their findings online in Astrophysical Journal Letters.
"We want to understand the evolution of tellurium -- and by extension any other element -- from the Big Bang to today," says Anna Frebel, an assistant professor of astrophysics at MIT and a co-author on the paper. "Here on Earth, everything's made from carbon and various other elements, and we want to understand how tellurium on Earth came about."
'In the halo of the Milky Way,' a rare element found
The team analyzed the chemical composition of three bright stars located a few thousand light-years away, "in the halo of the Milky Way," Frebel says. The researchers looked at data obtained from the Hubble Space Telescope's spectrograph, an instrument that splits light from a star into a spectrum of wavelengths. If an element is present in a star, the atoms of that element absorb starlight at specific wavelengths; scientists can observe this absorption as dips in the spectrograph's data.
Frebel and her colleagues detected dips in the ultraviolet region of the spectrum -- at a wavelength that matched tellurium's natural light absorption -- providing evidence that this element does indeed exist in space, and was likely created more than 12 billion years ago, at the time when all three stars formed.
The researchers also compared the abundance of tellurium to that of other heavy elements such as barium and strontium, finding that the ratio of elements was the same in all three stars. Frebel says the matching ratios support a theory of chemical-element synthesis: namely, that a rare type of supernova may have created the heavier elements in the bottom half of the periodic table, including tellurium.
No ordinary supernova
According to theoretical predictions, elements heavier than iron may have formed as part of the collapsing core of a supernova, when atomic nuclei collided with huge amounts of neutrons in a nuclear fusion process. For 50 years, astronomers and nuclear physicists have modeled this rapid process, named the r-process, in order to unravel the cosmic history of the elements.
Frebel's team found that the ratios of heavy elements observed in the three stars matched the ratios predicted by these theoretical models. The findings, she says, confirm the theory that heavier elements likely formed from a rare, extremely rapid supernova.
"You can make iron and nickel in any ordinary supernova, anywhere in the universe," Frebel says. "But these heavy elements seem to only be made in specialized supernovas. Adding more elements to the observed elemental patterns will help us understand the astrophysical and environmental conditions needed for this process to operate."
Jennifer Johnson, an associate professor of astronomy at Ohio State University, says tellurium has been a "tough" element to detect, since it absorbs light in the ultraviolet spectrum, which is impossible for ground-based telescopes to spot. The team's findings, she says, are a first step in identifying some of the most elusive elements in the universe.
"If you look at the periodic table, tellurium is right in the middle of these elements that are hard for us to measure," Johnson says. "If we need to understand how [the r-process] works in the universe, we really have to measure this part of the periodic table. It's really cool that they got this element in this sea of unknown-ness."
Frebel is continuing the search for heavy elements in space. For example, selenium -- which is similar to tellurium -- has yet to be detected in the universe. Tin, Frebel says, is also a difficult element to spot, as are many elements along the same row as tellurium in the periodic table.
"There are still quite a few holes," Frebel says. "Every now and then, we can add an element, and it adds another data point that makes our work easier."
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TAG:Cosmology Astrophysics Stars Inorganic Chemistry Chemistry Physics
2012-02-21
January chip sales fell 15% year-on-year, says analyst
LONDON – A number of factors are likely to have contributed to soft January chip sales according to Bruce Diesen, an analyst at Carnegie Group (Oslo, Norway).
The net effect would have been that January's actual global chip sales were 15 percent below what they were in January 2011. However, as one of the influences is the movement of the Chinese New Year from February in 2011 to January 2012 there is hope of a better-than-usual February to follow.
However, other factors remain problematic. These factors include: PC weakness and higher costs due to the continued aftermath of flooding in Thailand and observed weakness in the mobile phone handset and automotive business sectors.
The three-month average of global chip sales for January, as reported by the World Semiconductor Trade Statistics (WSTS) organization, is likely to be $22.7 billion, according to Diesen's data models. This would compare with a three-month average of $23.83 billion reported by WSTS for December 2011. Actual sales in January are set to be between 15 and 16 percent below where they were in January 2011, Diesen said.
"Although several chip makers indicated the inventory correction in Q4 has ended, our early indicator indicates that it continued into Q1," Diesen said.
Diesen said that both South Korea's broader technology exports and Japan's chip exports were down sharply in January. Korean handset exports were down 39 percent year-on-year partly due to the holiday shift from February in 2011 to January in 2012.
Diesen's forecast for growth in the semiconductor market in U.S. dollar terms in 2012 is a 2 percent increase.
Related links and articles:
Analyst's model predicts 3 percent chip market growth in 2012
Global chip sales squeeze 0.4 percent annual growth in 2011
Analyst sees chip sales rebound in December
Bullish Penn sees chip market growth of 8 percent in 2012
January chip sales fell 15% year-on-year, says analyst
TAG:Bruce Diesen Carnegie WSTS semiconductor
Terahertz CMOS debuts at ISSCC
PORTLAND, Ore.—Downsizing big bulky terahertz (THz) detectors for integration on CMOS image chips has been accomplished by the University of Texas (Dallas) with funding from the Semiconductor Research Corp. (SRC). Accomplished under SRC’s Focus Research Program, the demonstration of terahertz speeds on standard CMOS opens a door for a new slew of consumer devices that can see through solid objects.
"We can now build a CMOS image chip for a cell-phone-sized camera module that sees in the terahertz range," said Ken O, a professor and lead researcher for SRC’s program at UT Dallas and a key investigator in the Center for Circuit and System Solutions, a part of SRC’s Focus Center Research Program.
Today terahertz cameras are used, for instance, in the airport to see inside luggage and under clothing to detect hidden weapons, but the devices require expensive discrete components. By downsizing terahertz sensors for standard CMOS chips, the terahertz camera can be both size and cost reduced in the extreme.
"Inexpensive handheld terahertz cameras could be used to detect counterfeit money or documents, to see inside envelopes or packages, or to find where the studs, wires and pipes are in walls," said O.
A one-pixel CMOS terahertz image chip (left) can see through solid objects, here showing the inner workings of an old-school floppy disk.
Terahertz CMOS debuts at ISSCC
TAG:CMOS Complementary metal oxide semiconductor semiconductor sensor imager terahertz THz
"We can now build a CMOS image chip for a cell-phone-sized camera module that sees in the terahertz range," said Ken O, a professor and lead researcher for SRC’s program at UT Dallas and a key investigator in the Center for Circuit and System Solutions, a part of SRC’s Focus Center Research Program.
Today terahertz cameras are used, for instance, in the airport to see inside luggage and under clothing to detect hidden weapons, but the devices require expensive discrete components. By downsizing terahertz sensors for standard CMOS chips, the terahertz camera can be both size and cost reduced in the extreme.
"Inexpensive handheld terahertz cameras could be used to detect counterfeit money or documents, to see inside envelopes or packages, or to find where the studs, wires and pipes are in walls," said O.
A one-pixel CMOS terahertz image chip (left) can see through solid objects, here showing the inner workings of an old-school floppy disk.
Terahertz CMOS debuts at ISSCC
TAG:CMOS Complementary metal oxide semiconductor semiconductor sensor imager terahertz THz
Thermal Diffusivity Sensors: Temperature Sensors that Scale
SAN FRANCISCO—Thermal diffusivity based sensors are the future, according to professor Kofi Makinwa of Delft University of Technology, speaking at the International Solid States Circuits Conference here Monday (Feb. 20).
Makinwa said he has been working on the technology for six years and that their importance was increasing owing to the fact thermal sensors are to be found in practically any computer system.
“Systems would self-destruct if you let them have their own way,” he noted, explaining the need for a more practical heatsink.
With systems becoming increasingly multi-core, hot spots throughout the processor are increasing, said Makinwa. The problem is becoming progressively complex because the hot spots move dynamically based on various processes, he said.
“SoC monitoring needs a fast conversion rate since thermal transients can have milisecond time constraints,” said Makinwa, adding that they also needed to be very small and consume as little power as possible, though they didn’t necessarily need to be highly accurate.
Since most properties of silicon are temperature dependent, Makinwa said band gap temperature sensors were simply not good enough and that a different approach was needed.
“Heat diffusion is a mechanical process,” said Makinwa, noting that this needed to be more about phonons than electrons.
The system works by measuring the thermal delay between an on-chip heater and an on-chip relative temperature sensor. That delay can then be digitized or used to define the output frequency of an oscillator.
“Thermal diffusivity of silicon is strongly temperature dependent,” said Makinwa, noting that thermal diffusivity based sensors were fully CMOS compatible, were insensitive to doping variations, packaging stress and could operate at higher temperatures, even up to 250 degrees centigrade. They also have performance accuracy and speed that scales with process, said Makinwa.
Makinwa said proof-of-concept thermal diffusivity sensors have already been fabricated in 0.7μm and 0.18μm bulk CMOS, as well as in 0.5μm SOI technology and were found to work over a wide temperature range from -70°C to 170°C.
An implementation in 0.18μm bulk CMOS achieved an untrimmed inaccuracy of ±0.2°C (3σ) from -55°C to 125°C, said Makinwa, concluding that therefore, TD sensors were the best solution for thermal management in nanometer CMOS.
Thermal Diffusivity Sensors: Temperature Sensors that Scale
TAG:thermal silicon temperature sensors
Makinwa said he has been working on the technology for six years and that their importance was increasing owing to the fact thermal sensors are to be found in practically any computer system.
“Systems would self-destruct if you let them have their own way,” he noted, explaining the need for a more practical heatsink.
With systems becoming increasingly multi-core, hot spots throughout the processor are increasing, said Makinwa. The problem is becoming progressively complex because the hot spots move dynamically based on various processes, he said.
“SoC monitoring needs a fast conversion rate since thermal transients can have milisecond time constraints,” said Makinwa, adding that they also needed to be very small and consume as little power as possible, though they didn’t necessarily need to be highly accurate.
Since most properties of silicon are temperature dependent, Makinwa said band gap temperature sensors were simply not good enough and that a different approach was needed.
“Heat diffusion is a mechanical process,” said Makinwa, noting that this needed to be more about phonons than electrons.
The system works by measuring the thermal delay between an on-chip heater and an on-chip relative temperature sensor. That delay can then be digitized or used to define the output frequency of an oscillator.
“Thermal diffusivity of silicon is strongly temperature dependent,” said Makinwa, noting that thermal diffusivity based sensors were fully CMOS compatible, were insensitive to doping variations, packaging stress and could operate at higher temperatures, even up to 250 degrees centigrade. They also have performance accuracy and speed that scales with process, said Makinwa.
Makinwa said proof-of-concept thermal diffusivity sensors have already been fabricated in 0.7μm and 0.18μm bulk CMOS, as well as in 0.5μm SOI technology and were found to work over a wide temperature range from -70°C to 170°C.
An implementation in 0.18μm bulk CMOS achieved an untrimmed inaccuracy of ±0.2°C (3σ) from -55°C to 125°C, said Makinwa, concluding that therefore, TD sensors were the best solution for thermal management in nanometer CMOS.
Thermal Diffusivity Sensors: Temperature Sensors that Scale
TAG:thermal silicon temperature sensors
Welding nanowires with light
RESEARCH at Stanford School of Engineering have found a way to weld together meshes of nanowires with light.
A lot of work is currently being done on nanoelectronics, and one of these is the creation of electrically conductive meshes made of metal nanowires. These meshes could one day be used in touchscreens, displays, LEDs and thin-film solar cells.
However, to create such a mesh, nanowires must be melded together in a crisscross pattern. Pressing them together or heating them damages the nanowires.
The Stanford engineers utilised plasmonics to fuse the wires using light. Plasmonics is the physics behind the interaction of light and metal in which the light flows across the surface of the metal in waves.
If two nanowires are placed to criss-cross each other, light generates Plasmon waves at the intersection, creating a hot spot. This fuses the nanowires, after which the hot spot disappears, preventing damage from residual heat.
This light-based, self-limiting, highly precise heating increases the control, speed and energy efficiency of nanoscale welding, easing the creation of nanowire meshes.
According to the researchers, the new technique could also allow mesh electrodes to be bound to flexible or transparent plastics and polymers. For example, they sprayed a solution containing silver nanowires in suspension on a plastic wrap and dried it.
Upon inspection after illumination, the spray had left an ultrathin layer of welded nanowires. The wrap was balled up, and found to maintain its electrical properties upon unwrapping. It also maintained most of its transparency.
Prior to the plasmonics approach, the plastic wrap holding the nanowires would have had to be heated to weld them together, destroying the substrate.
Welding nanowires with light
TAG:nanotechnology research and development
Intel gives deeper look into Ivy Bridge
SAN FRANCISCO – Intel gave its first details public look into Ivy Bridge, the first processors to use its 22 nm tri-gate technology. Intel plans at least four major variants of the chip which packs 1.4 billion transistors into 160mm2 in its largest version.
Ivy Bridge packs 20 channels of PCI Express Gen 3 interconnect and a Displayport controller, Intel’s first chip to integrate PCIe. The move marks one small step into the long term quest of what an Intel executive called terascale-class clients.
The first Ivy Bridge chip targets a range of desktop, notebook, embedded and single-socket server systems with up to 8 Mbytes cache. Like previous Intel parts it integrates a memory controller and graphics, now upgraded to support DDR3L DRAMs and Microsoft DirectX 11.0 graphics APIs.
“We spent a lot of time on the modularity of this die to create different flavors of it very quickly,” said Scott Siers, an Intel engineer who presented a paper on the chip at the International Solid-State Circuits Conference here.
Specifically the largest die includes four x86 cores and a large graphics block. It can be chopped along its x- and/or y-axis using automated generation tools to create versions with two cores or a smaller graphics block.
Siers said Ivy Bridge is Intel’s first client chip to support low power 1.35V DDR3L and DDR power gating in standby mode. It handles up to 1,600 MTransfers/s as well as 1.5V DDR3. A new write assist cache circuit provides an average 100 millivolt power reduction.
The Displayport block supports three simultaneous displays including one 1.6 GHz and two 2.7 GHz links with four lanes each.
The PCIe receiver uses a continuous time linear equalizer with 32 gain control levels and a transmitter with a three-tap digital FIR filter. The PCIe block also supports on die testing for jitter as well as timing and voltage margin measurements.
The chip’s x86 and graphics cores can scale in data rates at 100 and 50 MHz increments respectively. Overall, the chip supports five power planes and 180 clock islands that can be separately gated.
In a separate ISSCC keynote, Dadi Perlmutter, chief product officer for Intel, scoped out a long term vision of terahertz-class clients. Terahertz systems consume as much as three kilowatts today but could be reduced to 20W by the end of the decade using a broad variety of techniques, he said.
The techniques include optimizing chips to work at near threshold voltage levels, a subject of several Intel papers at ISSCC. Lower power internal and external interconnects are also needed, he said.
3-D IC packaging will be needed to lower power memory, Permutter said. Toward that end Intel is working with Micron and others on its Hypercube stacked memory design, he said. The design could boost memory bandwidth ten-fold while cutting power to eight pico-joules per bit, down from 50-75 pj/bit in today’s DDR3, he added.
In addition, “voltage regulation has to go into the IC itself because inductance is too big off chip or even on package,” Perlmutter said. “When you have a lot of voltage regulators to turn on and off it becomes very complex to do on a package, so we are working on getting power regulators into the ICs,” he said.
Perlmutter said he sees another 30 years of engineering needed in computing. “For people who thought they could retire from this industry, I say there’s a lot more to do,” he said.
Dadi Perlmutter scoped out challenges to get to terahertz clients.
Intel gives deeper look into Ivy Bridge
TAG:Ivy Bridge Intel X86 Processors ISSCC Ultrabooks
Ivy Bridge packs 20 channels of PCI Express Gen 3 interconnect and a Displayport controller, Intel’s first chip to integrate PCIe. The move marks one small step into the long term quest of what an Intel executive called terascale-class clients.
The first Ivy Bridge chip targets a range of desktop, notebook, embedded and single-socket server systems with up to 8 Mbytes cache. Like previous Intel parts it integrates a memory controller and graphics, now upgraded to support DDR3L DRAMs and Microsoft DirectX 11.0 graphics APIs.
“We spent a lot of time on the modularity of this die to create different flavors of it very quickly,” said Scott Siers, an Intel engineer who presented a paper on the chip at the International Solid-State Circuits Conference here.
Specifically the largest die includes four x86 cores and a large graphics block. It can be chopped along its x- and/or y-axis using automated generation tools to create versions with two cores or a smaller graphics block.
Siers said Ivy Bridge is Intel’s first client chip to support low power 1.35V DDR3L and DDR power gating in standby mode. It handles up to 1,600 MTransfers/s as well as 1.5V DDR3. A new write assist cache circuit provides an average 100 millivolt power reduction.
The Displayport block supports three simultaneous displays including one 1.6 GHz and two 2.7 GHz links with four lanes each.
The PCIe receiver uses a continuous time linear equalizer with 32 gain control levels and a transmitter with a three-tap digital FIR filter. The PCIe block also supports on die testing for jitter as well as timing and voltage margin measurements.
The chip’s x86 and graphics cores can scale in data rates at 100 and 50 MHz increments respectively. Overall, the chip supports five power planes and 180 clock islands that can be separately gated.
In a separate ISSCC keynote, Dadi Perlmutter, chief product officer for Intel, scoped out a long term vision of terahertz-class clients. Terahertz systems consume as much as three kilowatts today but could be reduced to 20W by the end of the decade using a broad variety of techniques, he said.
The techniques include optimizing chips to work at near threshold voltage levels, a subject of several Intel papers at ISSCC. Lower power internal and external interconnects are also needed, he said.
3-D IC packaging will be needed to lower power memory, Permutter said. Toward that end Intel is working with Micron and others on its Hypercube stacked memory design, he said. The design could boost memory bandwidth ten-fold while cutting power to eight pico-joules per bit, down from 50-75 pj/bit in today’s DDR3, he added.
In addition, “voltage regulation has to go into the IC itself because inductance is too big off chip or even on package,” Perlmutter said. “When you have a lot of voltage regulators to turn on and off it becomes very complex to do on a package, so we are working on getting power regulators into the ICs,” he said.
Perlmutter said he sees another 30 years of engineering needed in computing. “For people who thought they could retire from this industry, I say there’s a lot more to do,” he said.
Dadi Perlmutter scoped out challenges to get to terahertz clients.
Intel gives deeper look into Ivy Bridge
TAG:Ivy Bridge Intel X86 Processors ISSCC Ultrabooks
2012-02-20
New brain connections form in clusters during learning
The researchers studied mice as they learned new behaviors, such as reaching through a slot to get a seed. They observed changes in the motor cortex, the brain layer that controls muscle movements, during the learning process. Specifically, they followed the growth of new "dendritic spines," structures that form the connections (synapses) between nerve cells.
"For the first time we are able to observe the spatial distribution of new synapses related to the encoding of memory," said Yi Zuo, assistant professor of molecular, cell and developmental biology at UC Santa Cruz and corresponding author of the paper.
In a previous study, Zuo and others documented the rapid growth of new dendritic spines on pyramidal neurons in the motor cortex during the learning process. These spines form synapses where the pyramidal neurons receive input from other brain regions involved in motor memories and muscle movements. In the new study, first author Min Fu, a postdoctoral researcher in Zuo's lab, analyzed the spatial distribution of the newly formed synapses.
Initial results of the spatial analysis showed that one third of the newly formed synapses were located next to another new synapse. These clustered synapses tended to form over the course of a few days during the learning period, when the mouse was repeatedly performing the new behavior. Compared to non-clustered counterparts, the clustered synapses were more likely to persist through the learning sessions and after training stopped.
In addition, the researchers found that after formation of the second spine in a cluster, the first spine grew larger. The size of the spine head correlates with the strength of the synapse. "We found that formation of a second connection is correlated with a strengthening of the first connection, which suggests that they are likely to be involved in the same circuitry," Zuo said. "The clustering of synapses may serve to magnify the strength of the connections."
Another part of the study also supported the idea that the clustered synapses are involved in neural circuits specific to the task being learned. The researchers studied mice trained first in one task and then in a different task. Instead of grabbing a seed, the mice had to learn how to handle a piece of capellini pasta. Both tasks induced the formation of clustered spines, but spines formed during the learning of different tasks did not cluster together.
The researchers also looked at mice that were challenged with new motor tasks every day, but did not repeat the same task over and over like the ones trained in seed-grabbing or capellini-handling. These mice also grew lots of new dendritic spines, but few of the new spines were clustered.
"Repetitive activation of the same cortical circuit is really important in learning a new task," Zuo said. "But what is the optimal frequency of repetition? Ultimately, by studying the relationship between synapse formation and learning, we want to find out the best way to induce new memories."
The study used mice that had been genetically altered to make a fluorescent protein within certain neurons in the motor cortex. The researchers used a special microscopy technique (two-photon microscopy) to obtain images of those neurons near the surface of the brain. The noninvasive imaging technique enabled them to view changes in individual brain cells of the mice before, during, and after learning a new behavior.
In addition to Zuo and first author Min Fu, the coauthors of the paper include UCSC graduate student Xinzhu Yu and Stanford University biologist Ju Lu. This research was supported by grants from the Dana Foundation and the National Institute of Mental Health.
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TAG:Nervous System Psychology Research Neuroscience Educational Psychology Mice Behavioral Science
Surprising molecular switch: Lipids help control the development of cell polarity
Over the last few years, Rong Li, Ph.D., and her team at the Stowers Institute for Medical Research have figured out many important details of the basic biochemical mechanism that establishes cell polarity in yeast. Now, using cutting-edge microscopy and advanced mathematics, the team has discovered a surprising new twist. In the March issue of Nature Cell Biology, predoctoral researcher Arupratan Das, Li, and five colleagues report that, in yeast, an enzyme literally flips a switch by moving molecules called phospholipids from the outer to the inner layer of the cell membrane.
What's more, all the molecules involved in this intricate mechanism are found not just in yeast, but in mammalian cells as well. That opens up new avenues for exploring how cell polarity is created in, say, liver cells, and whether or not glitches in the mechanism can contribute to disease. "Cell polarity is critical for the specialized function of the vast majority of cells," explains Li, who is also a professor in the Department of Molecular and Integrative Physiology at the University of Kansas Medical Center. "Our finding could lead to a lot of clues mechanistically. We're hoping that others will pick up on our discovery and apply it to the cells they study."
Several decades ago, scientists thought that cell polarity might result from external cues -- such as spatially localized chemical signals outside cells that tell the cells how to move and behave. However, researchers have also long noticed that without such localized signals cells can still polarize suggesting that the ability to polarize and bud is innate in the cell.
Li's team uncovered an important clue to the underlying process. Embedded in the cell membrane is a molecule, named Cdc42, that acts as a key regulator. In a non-polarized cell, Cdc42 is randomly distributed around the membrane, like stones randomly set in a brick wall. It also floats around within the cell.
When activated, Cdc42 stimulates the formation of a skeleton of microfilaments that guide free-floating Cdc42 towards the Cdc42 already in the membrane. Some parts of the membrane start out with a bit more Cdc42 than others and the process guided by the microfilaments concentrates the molecule in those areas. Eventually, cells ends up with a high concentration of Cdc42 in one spot -- the spot where the bud will emerge.
Of course it isn't that simple. Membrane-bound Cdc42 can diffuse away but can also be pulled out of the membrane by another molecule named Rdi1and then recycled back to the same spot on the membrane. The speed of the recycling determines how big the eventual spot will be, which directly affects the shape of the bud that grows out.
Imagine ants in a ditch, says Li. They keep running out. To keep them there, you pick them up and put them back. If your hands are fast, you can contain them in a very small area. If your hands are slow, the ants spread out more. It's the same in the yeast cell. Faster recycling of Cdc42 results in a smaller spot on the cell; slower recycling causes a bigger spot. In a 2009 paper, Li's team showed that the recycling process can be fast or slow.
So what controls the speed of Cdc42 dissociation and recycling? Li and her colleagues tackled the question by looking for genes that, when knocked out, affect the speed. They found one that slowed things way down. It was a big surprise. "It wasn't something we were envisioning," says Li. In fact, she wasn't even sure if her team would pursue it. The reason: The gene was for a type of an enzyme known as a lipid flippase, which literally flips lipids from one side of cell membranes to the other. And lipids are "really messy and hard to work with," she says. Predoctoral researcher Arupratan Das, however, was willing to take it on. "I have to give Das a lot of credit -- he's fearless," says Li.
Using cutting-edge fluorescence fluctuation spectroscopy, Das and his colleagues were able to chart the movement of molecules in live yeast cells, and figure out the role of the flippase. Here's what they found:
Near one end of the Cdc42 molecule is a patch with a net positive electrical charge. The cell membrane has a negative charge. As a result, the positively-charged patch of Cdc42 acts like a piece of Velcro, holding the molecule close to the membrane, allowing a lipid anchor at the end of Cdc42 to be stably inserted in the membrane. To pull out the Cdc42 for recycling, Rdi1 must grab this anchor. "Rdi1 cannot go into the membrane, so it needs the Velcro to be loosened," Li explains.
That's where the flippase enzyme comes in. The enzyme was known to flip a charge-neutral phospholipid to the inner layer of the membrane. The membrane thus becomes less negatively charged, allowing the Cdc42 anchor to slip out more easily. It's an example of how "a simple physical interaction can regulate the complex morphogenetic outcome observed during cell polarization," explains Das.
Case closed? Not quite. The researchers were hopeful that they'd uncovered the mechanism based upon their observations with living cells. But in a living cell "it's hard to rule out the effects of something else," says Li. So Das painstakingly created small bits of human-made, reconstituted membrane to test the mechanism. "It was a great challenge and required much troubleshooting before we performed it successfully," he recalls. After a year of effort, it worked. Using an imaging technique called total internal reflection fluorescence microscopy, the team was able to show that the charge of the membrane does indeed determine how fast Cdc42 can be pulled out by Rdi1.
The next challenge will be figuring out what controls the flippase. "There are some hints that it gets even messier -- that the flippase may be regulated by another kind of lipid in the membrane and perhaps other enzymes," says Li. But the work in the new paper is already opening the door to a better understanding of the development of cell polarity in all types of cells. And it points to the power of new experimental tools and mathematical analysis that can help track and count molecules in cells, says Li.
"What the study really highlights is the future of cell biology -- the ability to make these very accurate biochemical and biophysical measurements in single live cells and reconstituted systems, rather than using traditional bulk biochemical assays," says Li.
Researchers who also contributed to the study include Brian D. Slaughter, Jay R. Unruh, William D. Bradford, Richard Alexander and Boris Rubinstein at the Stowers Institute for Medical Research.
The work was part of a project funded by the National Institute of General Medical Sciences.
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Surprising molecular switch: Lipids help control the development of cell polarity
TAG:Stem Cells Lymphoma Lung Cancer Genetics Molecular Biology Cell Biology
Faulty fat sensor implicated in obesity and liver disease
The protein GPR120 is found on the surface of cells in the gut, liver and fat tissue and allows cells to detect and respond to unsaturated fatty acids from the diet, especially the omega-3 fatty acids which are believed to have a beneficial impact on health. Scientists found that mice deficient in GPR120 were more prone to developing obesity and liver disease when fed a high-fat diet. They also found that people with a certain mutation in the gene encoding GPR120, which stops the protein from responding to omega-3 fatty acids, were significantly more likely to be obese.
In the gut, when unsaturated fatty acids from food bind to GPR120, this stimulates the release of hormones that suppress appetite and stimulate the pancreas to secrete insulin. When fat cells sense high levels of fat in the blood through GPR120, it stimulates them to divide to produce more fat cells to store all the fat, reducing the risk of fatty liver and furring of the arteries. This mechanism could be an important pathway for bringing about some of the healthy effects of omega-3s.
When they were fed on a high-fat diet, mice that lacked GPR120 not only became obese but also had fatty livers, lower numbers of fat cells, and poor control of blood glucose. The researchers believe that mice that are deficient in GPR120 have difficulty storing excess fat in fat tissue. Instead, their bodies store fat in areas where it can cause health problems, like the liver, the muscles and in the walls of arteries. In humans, this pattern of obesity is associated with type 2 diabetes and heart disease.
The study involved scientists in the UK, France and Japan. It was led by Professor Philippe Froguel, from the School of Public Health at Imperial College London.
"Being overweight is not always unhealthy if you can make more fat cells to store fat," said Professor Froguel. "Some people seem to be unable to do this, and instead they deposit fat around their internal organs, which is very unhealthy. Our study suggests that in both mice and humans, defects in GPR120 combined with a high-fat diet greatly increase the risk of this unhealthy pattern of obesity. We think GPR120 could be a useful target for new drugs to treat obesity and liver diseases."
The researchers analysed the gene for GPR120 in 6,942 obese people and 7,654 controls to test whether differences in the code that carries instructions for making the protein contribute to obesity in humans. They found that one mutation that renders the protein dysfunctional increases a person's risk of obesity by 60 per cent. The researchers think this mutation mimics the effect of a bad diet lacking in unsaturated omega-3 fat.
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Faulty fat sensor implicated in obesity and liver disease
TAG:Obesity Cholesterol Diet and Weight Loss Mice Food Genetics
Liquid batteries to smooth road for renewable energy
RESEARCHERS at MIT claim liquid batteries could be useful as a long-life and low-cost solution for smoothing out the erratic power supplies of renewable energy sources.
The system uses high-temperature batteries whose liquid components naturally settle into distinct layers because of their different densities.
The three molten materials form the positive and negative poles of the battery, as well as a layer of electrolyte in between. All three layers are composed of materials that are abundant and inexpensive.
Donald Sadoway, the John F. Elliott Professor of Materials Chemistry at MIT and the senior author of the new paper, said the team explored many chemistries in order to find the right combination of electrical properties, density differences and availability.
One combination they found was to use magnesium for the negative electrode (top layer), a salt mixture containing magnesium chloride for the electrolyte (middle layer) and antimony for the positive electrode (bottom layer). The system would operate at a temperature of 700 degrees Celsius.
In this formulation, Sadoway explains, the battery delivers current as magnesium atoms lose two electrons, becoming magnesium ions that migrate through the electrolyte to the other electrode. There, they reacquire two electrons and revert to ordinary magnesium atoms, which form an alloy with the antimony.
To recharge, the battery is connected to a source of electricity, which drives magnesium out of the alloy and across the electrolyte, where it then rejoins the negative electrode.
The team has scaled up their experiments over the years, and now are working on a version which has 200 times the power storage capacity of the initial version.
The team is continuing to work on optimizing all aspects of the system, including the containers used to hold the molten materials and the ways of insulating and heating them, as well as ways of reducing the operating temperature to help cut energy costs.
Liquid batteries to smooth road for renewable energy
TAG:power supplies environmental electronics solar power
Yosemite's alpine chipmunks take genetic hit from climate change
The study, appearing Feb. 19, in the advance online publication of the journal Nature Climate Change, is one of the first to show a hit to the genetic diversity of a species because of a recent climate-induced change in the animals' geographic range. What's more, the genetic erosion occurred in the relatively short span of 90 years, highlighting the rapid threat changing climate can pose to a species.
With low genetic diversity a species can be more vulnerable to the effects of inbreeding, disease and other problems that threaten species survival, the researchers said.
"Climate change is implicated as the cause of geographic shifts observed among birds, small mammals and plants, but this new work shows that, particularly for mountain species like the alpine chipmunk, such shifts can result in increasingly fragmented and genetically impoverished populations," said study lead author Emily Rubidge, who conducted the research while a Ph.D. student at UC Berkeley's Museum of Vertebrate Zoology and the Department of Environmental Science, Policy and Management. "Under continued warming, the alpine chipmunk could be on the trajectory towards becoming threatened or even extinct."
Rubidge worked with Craig Moritz, professor of integrative biology and director of the Museum of Vertebrate Zoology; James Patton, professor emeritus of integrative biology and curator of the Museum of Vertebrate Zoology; and Justin Brashares, associate professor in the Department of Environmental Science, Policy and Management.
The new findings build upon previous research that found major shifts in the range of small mammals in Yosemite National Park since the early 1900s. In 2003, biologists at UC Berkeley began an ambitious resurvey of Yosemite's birds, mammals, reptiles and amphibians, retracing the steps originally taken between 1914 and 1920 by Joseph Grinnell, founder and former director of the Museum of Vertebrate Zoology.
The Grinnell Resurvey Project, led by Moritz and museum colleagues, found that many small mammals in Yosemite moved or retracted their ranges to higher, cooler elevations over the past century, a period when the average temperature in the park increased by 3 degrees Celsius, or about 5.4 degrees Fahrenheit.
It is no surprise that the alpine chipmunk (Tamias alpinus) would be more sensitive to the temperature change, since it is a high-elevation species endemic to California's Sierra Nevada, the researchers said. In the early 1900s, Grinnell and colleagues sighted alpine chipmunks at elevations of 7,800 feet. Now, the alpine chipmunk appears to be sticking to even higher elevations, retracting its range by about 1,640 feet upslope.
To test the genetic impact from that loss of geographic range, researchers compared genetic markers from 146 modern-day alpine chipmunks with those from 88 of their historical counterparts. Samples were collected from seven paired sites throughout Yosemite.
As a control, the researchers also looked at the genetics -- both historic and modern -- of lodgepole chipmunks (Tamias speciosus), a lower elevation species that had not changed its range over the past century.
The analysis of genetic markers revealed a significant decline in "allele richness" among the recently sampled alpine chipmunk populations compared with their historic counterparts. Moreover, the researchers noted that the modern chipmunks were more genetically differentiated across sites than in the past, a sign of increased fragmentation in the alpine chipmunk population.
In comparison, there were no significant changes in genetic diversity detected among the lodgepole chipmunks, a species found at elevations from 4,900 to 9,800 feet.
"Much of what we read and hear about the effects of climate change on biodiversity is based on model projections and simulations, and these models typically involve many moving parts and lots of uncertainty," said Brashares. "Thanks to the baseline provided by Joseph Grinnell's pioneering efforts in the early 20th century, we are able to go beyond projections to document how climate is altering life in California. The research led by Emily is novel and important because it shows empirically that climate change has led to the loss of genetic diversity in a wild mammal over the last several decades."
Moritz added that this study exemplifies how patterns of change in California's ecosystems can be uncovered through analyses of fossil, historic and modern records.
"At the heart of this whole enterprise is the incredibly dense historic record and specimens we have at UC Berkeley from 100 years ago," said Moritz. "These collections allow us to conduct sophisticated analyses to better understand how ecosystems are reacting to environmental changes, and to create more detailed models of future changes."
Other study co-authors are Marisa Lim, a UC Berkeley undergraduate student in integrative biology; and Cole Burton, former UC Berkeley graduate student in environmental science, policy and management (now a research associate at the University of Alberta in Canada).
Funding for this research was provided by the Natural Sciences and Engineering Research Council of Canada, UC Berkeley's Museum of Vertebrate Zoology, the Yosemite Fund, the National Geographic Society and the National Science Foundation.
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Yosemite's alpine chipmunks take genetic hit from climate change
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X-rays illuminate the interior of the Moon
The results are published in the Journal Nature Geoscience on 19 February 2012.
The team was led by Mirjam van Kan Parker and Wim van Westrenen from VU University Amsterdam and composed of scientists from the Universities of Paris 6/CNRS, Lyon 1/CNRS, Edinburgh, and the European Synchrotron Radiation Facility (ESRF) in Grenoble.
Five decades after the Apollo missions, the formation and geological history of the Moon still hold many secrets. The astronauts not only returned 380 kg of Moon rocks to Earth but also placed many scientific instruments on the lunar surface. Last year, NASA scientists published a new model for the make-up of the interior of the Moon, using Moonquake data from these Apollo-era seismometers. Renee Weber and her colleagues claim that the deepest parts of the lunar mantle, bordering on the small metallic core, are partially molten, by up to 30 per cent. In Earth, such bodies of magma tend to move towards the surface leading to volcanic eruptions. If the deep interior of the Moon contains so much magma, why don't we see spectacular volcanic eruptions at its surface?
The driving force for vertical movement of magma is the density difference between the magma and the surrounding solid material, making the liquid magma move slowly upwards like a bubble. The lighter the liquid magma is, the more violent the upward movement will be.
To determine the density of lunar magma, Wim van Westrenen and his colleagues synthesised moon rock in their laboratory in Amsterdam, using the composition derived from Apollo samples as their "recipe." The pressures and temperatures close to the core of the Moon are more than 45,000 bar and about 1500 degrees. It is possible to generate these extreme conditions with small samples, heating them with a high electric current while squashing them in a press. By measuring the attenuation of a powerful synchrotron X-ray beam at the ESRF traversing the sample both solid and molten, the density at high pressure and high temperature could be measured. "We had to use the most brilliant X-ray beam in the world for this experiment because the magma sample is so tiny and confined in a massive, highly absorbing container. Without a bright beam of X-rays, you cannot measure these density variations," says Mohamed Mezouar from the ESRF.
The measurements at the ESRF were combined with computer simulations to calculate the magma density at any location in the Moon.
Nearly all the lunar magmas were found to be less dense than their solid surroundings, similar to the situation on Earth. There is one important exception: small droplets of titanium-rich glass first found in Apollo 14 mission samples produce liquid magma as dense as the rocks found in the deepest parts of the lunar mantle today. This magma would not move towards the surface.
Such titanium-rich magma can only be formed by melting titanium rich solid rocks. Previous experiments have shown that such rocks were formed soon after the formation of the Moon at shallow levels, close to the surface. How did they get deep into the mantle? The scientists conclude that large vertical movements must have occurred early in the history of the Moon, during which titanium-rich rocks descended from near the surface all the way to the core-mantle boundary. "After descending, magma formed from these near-surface rocks, very rich in titanium, and accumulated at the bottom of the mantle -- a bit like an upside-down volcano. Today, the Moon is still cooling down, as are the melts in its interior. In the distant future, the cooler and therefore solidifying melt will change in composition, likely making it less dense than its surroundings. This lighter magma could make its way again up to the surface forming an active volcano on the Moon -- what a sight that would be! -- but for the time being, this is just a hypothesis to stimulate more experiments," concludes Wim van Westrenen.
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X-rays illuminate the interior of the Moon
TAG:Moon Space Missions NASA Space Exploration Solar System Pluto
2012-02-18
Fruit flies use alcohol as a drug to kill parasites
"We believe our results are the first to show that alcohol consumption can have a protective effect against infectious disease, and in particular against blood-borne parasites," says Todd Schlenke, the evolutionary geneticist who led the research.
"It may be that fruit flies are uniquely adapted to using alcohol as medicine," he adds, "but our data raise an important question: Could other organisms, perhaps even humans, control blood-borne parasites through high doses of alcohol?"
Current Biology is publishing the study, co-authored by Emory graduate student Neil Milan and undergraduate student Balint Kacsoh.
The results add to the growing body of evidence that some animals know how to use toxic substances found in nature as medicine.
Drosophila melanogaster, the common fruit fly that swirls around browning bananas in your kitchen, is an important biological model system. The Schlenke lab uses D. melanogaster to study how immune systems adapt to pathogens.
The fly larvae eat the rot, or fungi and bacteria, that grows on overripe, fermenting fruit. "They're essentially living in booze," Schlenke says. "The amount of alcohol in their natural habitat can range from 5 to 15 percent. Imagine if everything that you ate and drank all day long was 5-percent alcohol. We wouldn't be able to live like that, but fruit flies are really good at detoxifying alcohol."
Tiny, endoparasitoid wasps are major killers of fruit flies. The wasps inject their eggs inside the fruit fly larvae, along with venom that aims to suppress their hosts' immune response. If the venom is effective enough, the wasp egg hatches, and the wasp larva begins to eat the fruit fly larva from the inside out. Eventually, an adult wasp emerges from the remains of the fruit fly pupa.
Some fruit flies, however, can overcome the effects of wasp venom and mount an immune response against wasp eggs. The blood cells in these fly larvae swarm over the wasp eggs and release nasty chemicals to kill them, allowing the fruit fly larvae to grow into adults.
"A constant co-evolutionary battle is going on between the immune systems of the flies and the venoms of the wasps," Schlenke says. "Any new mechanism of defense that protects flies from wasps will tend to spread through fly populations by natural selection."
Schlenke wondered if the fruit flies could be tapping the toxic effects of alcohol in their natural habitat to fight off wasps.
To test the theory, the researchers used a bisected petri dish filled with the yeast that fruit flies are normally fed in a lab environment. The yeast on one side of the dish was mixed with 6 percent alcohol, while the yeast on the other side remained alcohol-free. The researchers then released fruit fly larvae into the dish, allowing them to freely move to either side.
After 24 hours, 80 percent of the fruit fly larvae that were infected with wasps were on the alcohol side of the dish, while only 30 percent of the non-infected fruit fly larvae were on the alcohol side.
"The strength of the result was surprising," Schlenke says. "The infected fruit flies really do seem to purposely consume alcohol, and the alcohol consumption correlates to much higher survival rates."
Infected fruit flies that consumed alcohol beat out the wasps in about 60 percent of the cases, compared to a 0 percent survival rate for fruit fly controls that fed on plain yeast.
"The wasps aren't as good as the flies at handling alcohol," Schlenke says.
A developing wasp knocked out within an alcohol-consuming fly larva dies in a particularly horrible way, he adds. "The wasp's internal organs disperse and appear to be ejected out of its anus. It's an unusual phenotype that we haven't seen in our wasps before," Schlenke says.
The lab repeated the experiment using another species of wasp that specializes in laying its eggs in D. melanogaster, rather than the generalist wasp used previously. Again, 80 percent of the infected flies wound up on the alcohol side of the dish, while only 30 percent of the uninfected flies did. But the alcohol diet was far less effective against the specialist wasps, killing them in only 10 percent of the cases.
"You would expect this kind of result," Schlenke says, "since the generalist wasp species can attack plenty of other flies, but the specialist wasps are under strong pressure to adapt to the alcohol-infused habitat of D. melanogaster."
The researchers hope that their data will lead to more studies of how alcohol may control pathogens in other organisms, including humans.
"Although many studies in humans have shown decreased immune function in chronic consumers of alcohol, little attempt has been made to assay any beneficial effect of acute or moderate alcohol use on parasite mortality or overall host fitness following infection," Schlenke says.
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Meet plants' and algae's common ancestor: Primitive organisms not always so simple, researcher says
The image appears as part of a "Perspective" article in the Feb. 17 issue of Science.
Fred Spiegel, professor of biological sciences in the J. William Fulbright College of Arts and Sciences, suggests what microscopic parts would have been present in this common ancestor based on findings by Dana Price of Rutgers University and his colleagues, who examined the genome of a freshwater microscopic algae and determined that it showed that algae and plants are derived from one common ancestor. This ancestor formed from a merger between some protozoan-like host and cyanobacterium, a kind of bacteria that use photosynthesis to make energy, that "moved in" and became the chloroplast of this first alga. Price and his colleagues show that today's algae and plants have to be descended from this first alga, but they give no idea what it looked like.
"The work that Price and his group did nailed down what the relationships are" between this organism, the algae and plants, and all other eukaryotes, organisms that have a true nucleus in their cells, Spiegel said. "Once you know that, you can compare the structure of cells and characteristics you see in algae and plants with other eukaryotes and get a reasonable idea of what the original critter must have looked like."
For many years, scientists have speculated that the original ancestor of plants and algae must have originated from a protozoan-like organism and cyanobacteria. They theorized that at some point in the distant past the cyanobacteria became part of the other organism and created the first alga, which in turn created the opportunity for the growth into the biodiversity found in plants that we see today.
However, other scientists argued that the diversity and complexity of plants and algae suggest multiple events where different organisms merged. They pointed out that some members of the plant kingdom have simple structures and therefore must be more primitive than others.
Price and his colleagues' studied the genome of an obscure alga called Cyanophora. Their results strongly suggest that the first alga arose about a billion to a billion and a half years ago. This alga became the ancestor to the group of algae containing Cyanophora, plus the group of algae that includes the red seaweeds, plus the group that includes the green algae and the land plants. Together, these organisms form the super group called Plantae.
Based on this research, Spiegel has put forth a hypothetical snapshot of what the common ancestor of Plantae, the "first alga," might have looked like.
"The common ancestor of Plantae was an organism with very complex cells and a complex life cycle," Spiegel said. While some members of the super group Plantae may have less complex cells and life cycles, this does not mean they pre-date the common ancestor. "They're simpler because they lost parts, not because they originated that way."
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Geoscientists use numerical model to better forecast forces behind earthquakes
William E. Holt, Ph.D., a professor in the Geosciences Department at Stony Brook University, and Attreyee Ghosh, Ph.D., a post doctoral associate, used their model to help explain the stresses that act on Earth's tectonic plates. Those stresses result in earthquakes not only at the boundaries between tectonic plates, where most earthquakes occur, but also in the plate interiors, where the forces are less understood, according to their paper, "Plate Motions and Stresses from Global Dynamic Models."
"If you take into account the effects of topography and all density variations within the plates -- the Earth's crust varies in thickness depending on where you are -- if you take all that into account, together with the mantle convection system, you can do a good job explaining what is going on at the surface," said Dr. Holt.
Their research focused on the system of plates that float on Earth's fluid-like mantle, which acts as a convection system on geologic time scales, carrying them and the continents that rest upon them. These plates bump and grind past one another, diverge from one another, or collide or sink (subduct) along the plate boundary zones of the world. Collisions between the continents have produced spectacular mountain ranges and powerful earthquakes. But the constant stress to which the plates are subjected also results in earthquakes within the interior of those plates.
"Predicting plate motions correctly, along with stresses within the plates, has been a challenge for global dynamic models," the researchers wrote. "Accurate predictions of these is vitally important for understanding the forces responsible for the movement of plates, mountain building, rifting of continents, and strain accumulation released in earthquakes."
Data for their global computer model came from Global Positioning System (GPS) measurements, which track the movements of Earth's crust within the deforming plate boundary zones; measurements on the orientation of Earth's stress field gleaned from earthquake faults; and a network of global seismometers that provided a picture of Earth's interior density variations. They compared output from their model with these measurements from Earth's surface.
"These observations -- GPS, faults -- allow one to test the completeness of the model," Dr. Holt said.
Drs. Ghosh and Holt found that plate tectonics is an integrated system, driven by density variations found between the surface of Earth all the way to Earth's core-mantle boundary. A surprising find was the variation in influence between relatively shallow features (topography and crustal thickness variations) and deeper large-scale mantle flow patterns that assist and, in some places, resist plate motions. Ghosh and Holt also found that it is the large-scale mantle flow patterns, set up by the long history of sinking plates, that are important for influencing the stresses within, and motions of, the plates.
Topography also has a major influence on the plate tectonic system, the researchers found. That result suggests a powerful feedback between the forces that make the topography and the 'push-back' on the system exerted by the topography, they explained.
While their model cannot accurately predict when and where earthquakes will occur in the short-term, "it can help at better understanding or forecasting earthquakes over longer time spans," Dr. Holt said. "Nobody can yet predict, but ultimately given a better understanding of the forces within the system, one can develop better forecast models."
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2012-02-17
Researchers make living model of brain tumor
Results appear in Theranostics.
Brown University scientists have created the first three-dimensional living tissue model, complete with surrounding blood vessels, to analyze the effectiveness of therapeutics to combat brain tumors. The 3-D model gives medical researchers more and better information than Petri dish tissue cultures.
The researchers created a glioma, or brain tumor, and the network of blood vessels that surrounds it. In a series of experiments, the team showed that iron-oxide nanoparticles ferrying the chemical tumstatin penetrated the blood vessels that sustain the tumor with oxygen and nutrients. The iron-oxide nanoparticles are important, because they are readily taken up by endothelial cells and can be tracked by magnetic resonance imaging.
Previous experiments have shown that tumstatin was effective at blocking endothelial cell growth in gliomas. The tests by the Brown researchers took it to another level by confirming, in a 3-D, living environment, the iron-oxide nanoparticles' ability to reach blood vessels surrounding a glioma as well as tumstatin's ability to penetrate endothelial cells.
"The 3-D glioma model that we have developed offers a facile process to test diffusion and penetration into a glioma that is covered by a blood vessel-like coating of endothelial cells," said Don Ho, a graduate student in the lab of chemistry professor Shouheng Sun and the lead author of the paper in the journal Theranostics. "This assay would save time and money, while reducing tests in living organisms, to examine an agent's 3-D characteristics such as the ability for targeting and diffusion."
The tissue model concept comes from Jeffrey Morgan, a bioengineer at Brown and a corresponding author on the paper. Building on that work, Ho and others created an agarose hydrogel mold in which rat RG2-cell gliomas roughly 200 microns in diameter formed. The team used endothelial cells derived from cow respiratory vessels, which congregated around the tumor and created the blood vessel architecture. The advantage of a 3-D model rather than Petri-dish-type analyses is that the endothelial cells attach to the tumor, rather than being separated from the substrate. This means the researchers can study their formation and growth, as well as the action of anti-therapeutic agents, just as they would in a living organism.
"You want to see nanoparticles that diffuse through the endothelial cells, which is lost in 2-D because you just have diffusion into media," Ho said.
Other 3-D tissue models have been "forced cell arrangements," Ho said. The 3-D glioma model, in contrast, allowed the glioma and the endothelial cells to assemble naturally, just as they would in real life. "It more clearly mimics what would actually happen," Ho explained.
The group then attached tumstatin, part of a naturally occurring protein found in collagen, to iron-oxide nanoparticles and dosed the mold. True to form, the nanoparticles were gobbled up by the endothelial cells. In a series of in vitro experiments, the team reported the tumstatin iron-oxide nanoparticles decreased vasculature growth 2.7 times more than under normal conditions over eight days. "The growth is pretty much flat," Ho said. "There's no new growth of endothelial cells." The next step is to test the tumstatin nanoparticles' performance in the 3-D environment.
"This model has significant potential to help in the testing and optimization of the design of therapeutic/diagnostic nanocarriers and determine their therapeutic capabilities," the researchers write.
Contributing authors include Nathan Kohler and Aruna Sigdel, in Brown's chemistry department; Raghu Kalluri, from the Harvard Medical School, who first discovered tumstatin's anti-blood vessel growth properties; and Chenjie Xu, who earned his doctorate in chemistry at Brown last May and is at Brigham and Women's Hospital in Boston.
The National Cancer Institute of the National Institutes for Health, the National Science Foundation's Nanoscale Interdisciplinary Research Teams, the Rhode Island Biotechnology/Biomanufacturing Training Initiative, and the Brown Department of Diagnostic Imaging Fund supported the research.
Morgan has an equity interest in MicroTissues Inc., which specializes in 3-D tissue products.
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Robot reconnoiters uncharted terrain
Industrial robots have been a familiar sight in the workplace for many years. In automotive and household appliance manufacture, for example, they have proved highly reliable on production and assembly lines. But now a new generation of high-tech helpers is at hand: Mobile robots are being used in place of humans to explore hazardous and difficult-to-access environments such as buildings in danger of collapsing, caves, or ground that has been polluted by an industrial accident. Equipped with sensors and optical cameras, these robots can help rescue services search for victims in the wake of natural disasters, explosions or fires, and can measure concentrations of hazardous substances.
There's just one problem: Often there is no map to show them the location of obstacles and steer them along navigable routes. Yet such maps are critical to ensuring that the high-tech machines are able to make progress, either independently or guided by remote control. Researchers at the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation IOSB in Karlsruhe have now developed a roaming land robot that autonomously reconnoiters and maps uncharted terrain. The robot uses special algorithms and multi-sensor data to carve a path through unknown territory.
"To be able to navigate independently, our mobile robot has to fulfill a number of requirements. It must be able to localize itself within its immediate surroundings, continuously recalculate its position as it makes its way through the danger area, and simultaneously refine the map it is generating," says graduate engineer Christian Frey of the IOSB. To make this possible, he and his team have developed an algorithm toolbox for the robot that runs on a built-in computer. The robot is additionally equipped with a variety of sensors. Odometry sensors measure wheel revolutions, inertial sensors compute accelerations, and distance-measuring sensors register clearance from walls, steps, trees and bushes, to name but a few potential obstacles. Cameras and laser scanners record the environment and assist in the mapping process. The algorithms read the various data supplied by the sensors and use them to determine the robot's precise location. The interplay of all these different elements concurrently produces a map, which is updated continuously. Experts call the process Simultaneous Localization and Mapping, or SLAM.
Mobile robots face an additional challenge: to find the optimal path that will enable them to complete each individual task. Depending on the situation, this may be the shortest and quickest route, or perhaps the most energy-efficient, i.e. the one that uses the least amount of gasoline. When planning a course, the high-tech helpers must take into account restrictions on mobility such as a limited turning circle, and must navigate around obstacles. And should the environment change, for example as a result of falling objects or earthquake aftershocks, a robot must register this and use its toolbox to recalculate its route.
"We made our toolbox modular, so it's not difficult to adapt the algorithms to suit different types of mobile robot or specific in- or outdoor application scenarios. For example, it doesn't matter what sensor set-up is used, or whether the robot has two- or four-wheel drive," says Frey. The software can be customized to meet the needs of individual users, with development work taking just a few months. Frey adds: "The toolbox is suitable for all sorts of situations, not only accident response scenarios. It can be installed in cleaning robots or lawnmowers, for example, and a further possible application would be in roaming robots used to patrol buildings or inspect gas pipelines for weak points." From March 6-10, the IOSB researchers will be demonstrating their mobile robot technology at the CeBIT trade fair.
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