- How improved batteries will make electric vehicles competitive
- Iran warplane fired at US drone in early November
- New stem-cell-derived cells hold promise for Alzheimer’s, other brain diseases
- Stronger than a speeding bullet, but lighter
- Discovery may help nerve regeneration in spinal injury
Posted: 09 Nov 2012 05:10 AM PST
For electric vehicles and plug-in hybrids to compete with gas-powered cars, battery prices need to drop by between 50 and 80 percent, according to recent estimates by the U.S. Department of Energy.
Improvements to the lithium-ion batteries that power the current generation of electric vehicles may be enough, MIT Technology Review reports.
Electric vehicles cost less to operate than gas-powered ones, but that economic advantage largely disappears in the face of expensive batteries. The battery pack for the Chevrolet Volt costs about $8,000. The larger battery in the Nissan Leaf costs about $12,000.
But the cost for the Leaf battery could drop to under $4,000 by 2025, according to a recent study by McKinsey, just by increasing the scale of battery production, forcing down component costs through competition, and approximately doubling the energy density of batteries, which reduces materials costs.
One startup, Envia Systems, has already built prototype lithium-ion battery cells that store about twice that of the best conventional lithium-ion batteries and can be recharged hundreds of times (see "A Big Jump in Battery Capacity" and "Should the Government Support Applied Research?"). And crucially, it's similar enough to conventional lithium-ion batteries that it can be made on existing manufacturing equipment. The technology still needs work, and could take several years to start appearing in cars, the company says.
Not everyone agrees that lithium-ion batteries can reach the low costs needed for electric vehicles to compete with gas-powered ones (see "A123's Technology Just Wasn't Good Enough"). Toyota, for one, is investigating more dramatic changes in battery design. One type it's developing replaces the liquid electrolyte in a conventional lithium-ion battery with a solid material, something that allows for a number of changes in the battery design that could shrink the system and lower the cost. These solid-state batteries and other technologies could cut the size of a battery pack by 80 percent, according to Toyota. Sakti3, a startup with close ties to GM, is also developing solid-state batteries, and recently started shipping prototype batteries to potential customers for testing, says CEO Ann Marie Sastry (see "Solid-State Batteries").
24M, an early-stage startup based in Cambridge, Massachusetts, is taking a different approach — rather than an all-solid battery, the company is developing a cross between a battery and a fuel cell in which the battery electrodes are a sludgy liquid that can be pumped around. The energy storage material could be stored in inexpensive tanks, and then pumped into a small device to generate power (see "A Car Battery at Half the Price").
Despite the novel designs, solid-state batteries and 24M's technology still operate with a familiar lithium-ion chemistry, which could make them less risky to commercialize than more radical approaches that move beyond the lithium-ion chemistry. But these new batteries have theoretical energy densities several times that of today's electric car batteries.
Posted: 09 Nov 2012 05:04 AM PST
An Iranian warplane opened fire on an unarmed U.S. military drone conducting surveillance near Iranian airspace Nov. 1, the Pentagon said Thursday, the first such incident over the Persian Gulf and one that is all but certain to draw attention to Washington's use of unmanned aircraft, The Washington Post reports.
The MQ-1 Predator drone returned to its base unscathed, even as the Iranian aircraft chased it away from the Islamic Republic's borders, Pentagon spokesman George Little said Thursday, disclosing details of an incident that the Obama administration chose to keep quiet during the final stretch of the presidential campaign.
The Nov. 1 incident happened at 4:50 a.m. Eastern time, approximately 16 miles from the Iranian coastline, Little said. Under international law, national sovereignty extends for 12 nautical miles.
Posted: 09 Nov 2012 04:53 AM PST
Dr. Edwin Monuki of UCI's Sue & Bill Gross Stem Cell Research Center and colleagues developed these cells — called choroid plexus epithelial cells (CPECs) — from existing mouse and human embryonic stem cell lines.
CPECs are critical for proper functioning of the choroid plexus, the tissue in the brain that produces cerebrospinal fluid (CSF ). CPECs make CSF and remove metabolic waste and foreign substances from the fluid and brain, among other tasks.
In neurodegenerative diseases, the choroid plexus and CPECs age prematurely, resulting in reduced CSF formation and decreased ability to flush out the plaque-forming proteins that are a hallmark of Alzheimer's. Transplant studies have provided proof of concept for CPEC-based therapies. However, such therapies have been hindered by the inability to expand or generate CPECs in culture.
"Our method is promising, because for the first time we can use stem cells to create large amounts of these epithelial cells, which could be utilized in different ways to treat neurodegenerative diseases," said Monuki, an associate professor of pathology & laboratory medicine and developmental & cell biology at UCI.
To create the new cells, Monuki and his colleagues coaxed embryonic stem cells to differentiate into immature neural stem cells. They then developed the immature cells into CPECs capable of being delivered to a patient's choroid plexus.
These cells could be part of neurodegenerative disease treatments in at least three ways, Monuki said. First, they're able to increase the production of CSF to help flush out plaque-causing proteins from brain tissue and limit disease progression. Second, CPEC "superpumps" could be designed to transport high levels of therapeutic compounds to the CSF, brain and spinal cord. Third, these cells can be used to screen and optimize drugs that improve choroid plexus function.
Monuki said the next steps are to develop an effective drug screening system and to conduct proof-of-concept studies to see how these CPECs affect the brain in mouse models of Huntington's, Alzheimer's and pediatric diseases.
The study as supported by the National Institutes of Health, the California Institute for Regenerative Medicine, UCI's Institute for Clinical & Translational Science, and UCI's Alzheimer's Disease Research Center.
Posted: 09 Nov 2012 04:08 AM PST
While traditional shields have been made of bulky materials such as steel, body armor made of lightweight material such as Kevlar has shown that thickness and weight are not necessary for absorbing the energy of impacts.
The key is to use composites made of two or more materials whose stiffness and flexibility are structured in very specific ways — such as in alternating layers just a few nanometers thick. The research team produced miniature high-speed projectiles and measured the effects they had on the impact-absorbing material.
The results of the research are reported in the journal Nature Communications, in a paper co-authored by former postdoc Jae-Hwang Lee, now a research scientist at Rice; postdoc Markus Retsch; graduate student Jonathan Singer; Edwin Thomas, a former MIT professor who is now at Rice; graduate student David Veysset; former graduate student Gagan Saini; former postdoc Thomas Pezeril, now on the faculty at Université du Maine, in Le Mans, France; and chemistry professor Keith Nelson. The experimental work was conducted at MIT's Institute for Soldier Nanotechnologies.
The researchers developed a self-assembling polymer with a layer-cake structure: rubbery layers, which provide resilience, alternating with glassy layers, which provide strength. They then developed a method for shooting glass beads at the material at high speed by using a laser pulse to rapidly evaporate a layer of material just below its surface.
Though the beads were tiny — just millionths of a meter in diameter — they were still hundreds of times larger than the layers of the polymer they impacted: big enough to simulate impacts by larger objects, such as bullets, but small enough so the effects of the impacts could be studied in detail using an electron microscope.
Seeing the layers
Structured polymer composites have previously been tested for possible impact-protection applications. But nobody had found a way to study exactly how they work — so there was no way to systematically search for improved combinations of materials.
The new techniques developed by the MIT and Rice researchers could provide such a method. Their work could accelerate progress on materials for applications in body and vehicle armor; shielding to protect satellites from micrometeorite impacts; and coatings for jet engine turbine blades to protect from high-speed impacts by sand or ice particles.
The methods the team developed for producing laboratory-scale high-speed impacts, and for measuring the impacts' effects in a precise way, "can be an extremely useful quantitative tool for the development of protective nanomaterials," says Jae-Hwang Lee, now a research scientist at Rice, the lead author of the paper, who did much of this research while in MIT's Department of Materials Science and Engineering. "Our work presents some valuable insights to understand the contribution" of the nanoscale structure to the way such materials absorb an impact, he says.
Because the layered material has such a predictable, ordered structure, the effects of the impacts are easily quantified by observing distortions in cross-section. "If you want to test out how ordered systems will behave," Singer says, "this is the perfect structure for testing."
The work was supported by the U.S. Army Research Office.
Posted: 09 Nov 2012 04:00 AM PST
It is known that scar tissue, which forms following spinal cord injury, creates an impenetrable barrier to nerve regeneration, leading to the irreversible paralysis associated with spinal injuries. The scientists found that long-chain sugars, called heparan sulfates, play a significant role in the process of scar formation in cell models in the laboratory.
Scarring results from the activation, change in shape, and stiffening of astrocyte cells, Chthe major nerve support cells in the spinal cord. One possible way to repair nerve damage is transplantation of support cells from peripheral nerves, called Schwann cells. The team, however, found that these cells secrete heparan sulfate sugars, which promote scarring reactions and could reduce the effectiveness of nerve repair.
"We found that some sugar types promote scarring reaction, but remarkably other types, which can be chemically produced in the laboratory by modifying heparin, can prevent this in our cell models," Professor Jerry Turnbull, from the University of Liverpool's Institute of Integrative Biology. "Studies in animal cells are now needed, but the exciting thing about this work is that it could, in the future, provide a way of developing treatments for improving nerve repair in patients, using the body's own Schwann cells, supplemented with specific sugars."
The research, funded by the Wellcome Trust, is published in the Journal of Neuroscience.
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