Back to the main page

Archives Of Science Blog

Subscribe To Science Blog RSS Feed  RSS content feed What is RSS feed?


April 10, 2007, 8:43 PM CT

Nanoparticles improve delivery of medicines

Nanoparticles improve delivery of medicines
Tiny, biodegradable particles filled with medicine may also contain answers to some of the biggest human health problems, including cancer and tuberculosis. The secret is the size of the package.

Using an innovative technique they invented, a Princeton University-led research team has created particles that can deliver medicine deep into the lungs or infiltrate cancer cells while leaving normal ones alone. Only 100 to 300 nanometers wide -- more than 100 times thinner than a human hair -- the particles can be loaded with medicines or imaging agents, like gold and magnetite, that will enhance the detection capabilities of CT scans and MRIs.

"The intersection of materials science and chemistry is allowing advances that were never before possible," said Robert Prud'homme, a Princeton chemical engineering professor and the director of a National Science Foundation-funded team of researchers at Princeton, the University of Minnesota and Iowa State University. "No one had a good route to incorporate drugs and imaging agents in nanoparticles".

Prud'homme will discuss the work April 11 in a talk titled "How Size Matters in the Retention of Nanomaterials in Tissue," to be given at the National Academy of Sciences meeting on Nanomaterials in Biology and Medicine in Washington, D.C.........

Posted by: John      Read more         Source


April 3, 2007, 10:38 PM CT

Financial Risks Of Nuclear Power Plants

Financial Risks Of Nuclear Power Plants
Berkeley -- Enticed by the gleam of government subsidies, a number of companies are rushing to invest in nuclear power, expecting that new technology and safer reactors will make them as good an investment as other types of power plants.

A new study appearing in the April 1 issue of the journal Environmental Science and Technology notes, however, that the country's history of unexpected cost overruns when building nuclear plants should sound a cautionary note for power companies that nuclear power may not be financially attractive.

"For energy security and carbon emission concerns, nuclear power is very much back on the national and international agenda," said co-author of study Dan Kammen, UC Berkeley professor of energy and resources and of public policy. "To evaluate nuclear power's future, it is critical that we understand what the costs and the risks of this technology have been. To this point, it has been very difficult to obtain an accurate set of costs from the U. S. fleet of nuclear power plants".

The study, conducted by a research team from Georgetown University, Stanford University and UC Berkeley, analyzes the costs of electricity from existing U.S. nuclear reactors and discusses the possibility for cost "surprises" in new energy technologies, including next-generation nuclear power.........

Posted by: Edna      Read more         Source


April 3, 2007, 10:12 PM CT

The global carbon budget

The global carbon budget
Life as we know it, from the most basic microbes to our human neighbors, is carbon based. By investigating how carbon cycles through ecosystems, researchers can learn valuable information about food chains, nutrient cycling, and productivity. Because carbon dioxide is a greenhouse gas, with the ability to influence temperature, an accurate global carbon budget is needed to address climate change.

On Earth, carbon is continually cycling through terrestrial systems, inland waters, the ocean, and the atmosphere. Until little over a decade ago, when calculating the terrestrial component of the global carbon budget, inputs were limited to the ocean and the land. Because inland water bodies cover less than 1% of the Earths surface, it was assumed that their contribution was inconsequential.

This view was recently challenged in an Ecosystems paper highlighting the findings of a National Center for Ecological Assessment and Synthesis analysis. Carried out by a team of international scientists, including Institute of Ecosystem Studies Biogeochemist Dr. Jonathan J. Cole, the papers senior author, the group reveals that inland water bodies are important areas of terrestrial carbon transformation that deserve inclusion in global carbon cycle assessments.

While rivers were introduced into global carbon budget assessments in the late 90s, Cole and his colleagues argue that current models are limited by a narrow definition of how rivers transport carbon. By depicting rivers as "pipes" that passively deliver terrestrial carbon to the sea, models fail to capture the complex transformations that occur on the journey toward the ocean. The fact is, as per the authors, that half of the terrestrial carbon entering inland waters is destined for a fate outside of the oceans salty shores.........

Posted by: Edwin      Read more         Source


April 2, 2007, 10:12 PM CT

Increasing Effectiveness Of Tsunami Warning

Increasing Effectiveness Of Tsunami Warning
Scientists at the University of Nevada, Reno are at the forefront on a number of seismological fields, including helping the world better determine whether an earthquake is big enough to generate an ocean-wide tsunami.

Through work at the Nevada Seismological Laboratory on the Nevada campus, important data on seismological events throughout the world is compiled, including Mondays fatal occurrence in the Solomon Islands, where at least 13 people were killed. Tsunamis triggered by an undersea earthquake crashed ashore and wiped away entire villages and set off alerts from Australia to Hawaii.

A research team led by Geoffrey Blewitt of the Nevada Bureau of Mines and Geology and Seismological Laboratory has demonstrated that a large quakes true size can be determined within 15 minutes using Global Positioning System data. This swift exchange of information, which is much faster than is possible with current methods, can be critical in determining whether an earthquake might trigger a tsunami. Together with a seismometer and ocean buoy data, GPS has the potential to become an important tool in improving tsunami danger assessments, Blewitt said.

"We'll always need seismology as the first level of alert for large earthquakes, and we'll need ocean buoys to actually sense the tsunami waves," said Blewitt, whose work was originally accomplished through the NASA-funded Jet Propulsion Laboratory in Pasadena, Calif. Blewitts team recently was granted further funding from the U.S. Geological Surveys Natural Hazards Reduction Program to continue research and development.........

Posted by: John      Read more         Source


April 1, 2007, 9:40 PM CT

The gigantic respiration of crystalline solids

The gigantic respiration of crystalline solids Structure of chromium (III) diphenyl dicarboxylate
Credit: G. Ferey - CNRS 2007
Previously, only amorphous polymer materials approached such levels of performance. On the other hand, these gigantic respiration and their respiration, which takes place at constant overall shape, is reversible. This discovery, of interest for numerous industrial applications, is published in the journal Science on March 30, 2007.

The phenomenon of respiration is normally associated with life. Typically typically it is characterized by a reversible variation in the volume of a species under the effect of a stimulus (gas, pressure, temperature, irradiation, etc.). The volume of the lungs, for example, expands by 40 percent when breathing in. Organic matter, known for its flexibility, is well suited to this phenomenon. On the other hand, inorganic matter is very often associated with the idea of rigidity and non-deformability. Researchers from the Institut Lavoisier (CNRS/Universit de Versailles Saint-Quentin-en-Yvelines) have recently demonstrated that the hybrid material (which combines both inorganic and organic entities) can be deformed in a reversible manner.

Within the framework of their studies on porous systems, Grard Frey and his team at the Institut Lavoisier have discovered a new family of trivalent metal dicarboxylates, which possess unprecedented respiration properties. Depending on the nature of the organic entity, the variation in volume when these solids are immersed in a solvent (water, methanol, etc.) can exceed 300 percent. Only some amorphous polymers approach this level of performance. However, unlike such polymers, the new solids are crystalline. The researchers determined their crystallographic structure in each state (solvated or not) and provided an explanation for the respiration mechanism, which takes place at constant overall shape, without any apparent rupture of bonds at the atomic level. The reversibility of the phenomenon is therefore facilitated.........

Posted by: Nora      Read more         Source


March 29, 2007, 10:26 PM CT

Prototype for long wavelength array

Prototype for long wavelength array Photograph of the 16-element LWDA, with a National Radio Astronomy Observatory Very Large Array (VLA) dish visible in the background.
Astronomers at the Naval Research Laboratory (NRL) have produced the first images of the sky from a prototype of the Long Wavelength Array (LWA), a revolutionary new radio telescope to be constructed in southwestern New Mexico. The images show emissions from the center of our Galaxy, a supermassive black hole, and the remnant of a star that exploded in a supernova over 300 years ago. Not only a milestone in the development of the LWA, the images are also a first glimpse through a new window on the cosmos. "First light" is an astronomical term for the first image produced with a telescope. It is a key milestone for any telescope because it indicates that all of the individual components are working in unison as planned.

Once completed, the LWA will provide an entirely novel view of the sky, in the radio frequency range of 2080 MHz, currently one of the most poorly explored regions of the electromagnetic spectrum in astronomy. The LWA will be able to make sensitive high-resolution images, and scan the sky rapidly for new and transient sources of radio waves, which might represent the explosion of distant, massive stars, the emissions from planets outside of our own solar system or even previously unknown objects or phenomena.

"The LWA will allow us to make the sharpest images ever possible using very long wavelength radio waves. This newly opened window on the universe will help us understand the acceleration of relativistic particles in a variety of extreme astrophysical environments including from the most distant supermassive black holes. But perhaps most exciting is the promise of new source classes waiting to be discovered," says Dr. Namir Kassim, an NRL astronomer in the Remote Sensing Division and LWA Project Scientist. Dr. Tracy Clarke, of Interferometrics, Inc. in Herndon, Virginia, another astronomer on the NRL team adds, "By detecting distant clusters of galaxies the LWA may also provide new insights on the cosmological evolution of the mysterious dark matter and dark energy".........

Posted by: John      Read more         Source


March 29, 2007, 10:07 PM CT

Nanoparticles can track cells

Nanoparticles can track cells This image combines three MRI scans of a mouse: one is a typical scan showing internal organs.
To the delight of scientists at Washington University School of Medicine in St. Louis, living cells gobbled up fluorine-laced nanoparticles without needing any coaxing. Then, because of the unusual meal, the cells were easily located with MRI scanning after being injected into mice.

Developed in the laboratories of Samuel A. Wickline, M.D., and Gregory Lanza, M.D., Ph.D., the nanoparticles could soon allow scientists and physicians to directly track cells used in medical therapys using unique signatures from the ingested nanoparticle beacons.

In an article that will appear in the recent issue of the FASEB Journal, lead author Kathryn C. Partlow, a doctoral student in Wickline's lab, describes using perfluorocarbon nanoparticles to label endothelial progenitor cells taken from human umbilical cord blood. Such cells can be primed to help build new blood vessels when injected into the body. The scientists believe nanoparticle-labeled stem cells like these could prove useful for monitoring tumors and diagnosing and treating cardiovascular problems.

The nanoparticles contain a fluorine-based compound that can be detected by MRI scanners. Fluorine is most usually known for being an element included in fluoride toothpastes. Wickline, who heads the Siteman Center of Cancer Nanotechnology Excellence, says this technology offers significant advantages over other cell-labeling technologies under development.........

Posted by: John      Read more         Source


March 29, 2007, 10:04 PM CT

Omega-3 Fatty Acid And Alzheimer's Disease?

Omega-3 Fatty Acid And Alzheimer's Disease? Eating fish may help reduce the risk for dementia.
Nutritionists have long endorsed fish as part of a heart-healthy diet, and now some studies suggest that omega-3 fatty acids found in the oil of certain fish may also benefit the brain by lowering the risk of Alzheimer's disease. In order to test whether docosahexaenoic acid (DHA), an omega-3 fatty acid, can impact the progression of Alzheimer's disease, researchers at Washington University School of Medicine and Saint Louis University School of Medicine will evaluate DHA in a clinical trial sponsored by the National Institute on Aging (NIA).

The local effort is part of a nationwide consortium of leading Alzheimer's disease researchers supported by the NIA and coordinated by the University of California, San Diego. The trial will take place at 52 sites across the United States. It seeks 400 participants age 50 and older with mild to moderate Alzheimer's disease. Joseph Quinn, M.D., associate professor of neurology at Oregon Health and Science University, is directing the national study. James Galvin, M.D., M.P.H., at Washington University School of Medicine, and George Grossberg, M.D., at Saint Louis University School of Medicine, will conduct the study locally.

Researchers will primarily evaluate whether taking DHA over many months slows both cognitive and functional decline in people with mild to moderate Alzheimer's. During the 18-month clinical trial, scientists will measure the progress of the disease using standard tests for functional and cognitive change.........

Posted by: Nora      Read more         Source


March 27, 2007, 7:07 PM CT

Scientists Explain Source of Tiny Tremors

Scientists Explain Source of Tiny Tremors
Tiny earthquakes called non-volcanic tremors recently discovered in fault zones from California to Japan are generated by slow-moving earthquakes that may foreshadow catastrophic events, as per researchers at Stanford University and the University of Tokyo.

As per a research findings reported in the March 15 issue of the journal Nature, seismologists say their findings may be useful in understanding potentially destructive mega-quakes of magnitude 8 or higher. The research was funded by the National Science Foundation (NSF).

"This work gives us a way to use different types of seismic activity to monitor places where large, destructive earthquakes occur," said Eva Zanzerkia, program director in NSF's Division of Earth Sciences.

Gregory Beroza, a geophysicist at Stanford and co-author of the Nature study, said that non-volcanic tremors are often accompanied by low-frequency earthquakes (LFEs)--small quakes of magnitude 1 or 2.

To date, LFEs have been found primarily in subduction zones--seismically active faults where two tectonic plates meet and one plate constantly dives beneath the other. A recent example was the devastating 2004 earthquake near Sumatra, where a magnitude 9.2 quake triggered powerful tsunamis that killed more than 200,000 people.........

Posted by: John      Read more         Source


March 25, 2007, 8:13 PM CT

Not All Nanomaterials Are Created Equal

Not All Nanomaterials Are Created Equal Acid-Treated Nanotubes Interact with E. Coli for 15.5 Days
Troy, N.Y. The size, type, and dispersion of nanomaterials could all play a role in how these materials impact human health and the environment, as per two groups of scientists at Rensselaer Polytechnic Institute. In new studies, the teams observed that while carbon nanotubes inhibited growth in mammalian cells, they sustained the growth of usually occurring bacteria.

The seemingly contradictory findings highlight the need for society to better grasp the impacts these infinitesimally small particles could have when released into the environment or the human body, the scientists said. Both results were presented at the 233rd American Chemical Society (ACS) National Meeting in Chicago, March 25-29, 2007.

In the first study, which was led by Assistant Professor of Biomedical Engineering Deanna M. Thompson, scientists examined the impact of carbon nanotubes on the growth of rat heart muscle cells to better understand how they affect mammalian cells and ultimately human tissue and organs. Unlike prior research that focused on the effects of nanotube clusters on cell growth, this study looked at both the impacts of clusters and related finely dispersed material composed of small bundles of nanotubes and other nanoparticulate impurities.

The scientists discovered that the finely dispersed material, despite its low concentration, inhibited animal cell growth more than larger clusters of nanotubes. Activated carbon, a usually used nanoporous carbon material, had a lower impact on the cells than either the large aggregates or the finely dispersed material. The findings of this study were recently reported in the journal Toxicology Letters.........

Posted by: John      Read more         Source


Older Blog Entries   Older Blog Entries   1   2   3   4   5   6   7   8   9   10   11   12   13   14   15   16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31   32   33   34   35   36   37   38   39   40   41   42   43   44   45   46   47   48   49   50   51   52   53   54   55