Archive for dezembro 19th, 2013

Colloidal Suspensions: Principios na Formaçao dos Sistemas Terrestres, Frequencias da Luz, etc., a Pesquisar

quinta-feira, dezembro 19th, 2013

Na formação de processos e sistemas na Terra, vieram os princípios, forças e elementos ancestrais. Tendo ou não os fótons da Matrix, preciso entender esta evolução.

Colloidal suspensions of microspheres in a liquid may not be simple systems

Colloidal suspensions of microspheres in a liquid may not be simple systems

The static structure factor of the microsphere suspension (left panel) and the effective inverse diffusion constant of microspheres (right panel) show similar dependency on scattering vector, which suggests that the lowest free-energy configuration in the static case also has a long lifetime.

Read more at:

Itens: Brownian Motion, polystyrene,

Importantes textos:

Colloidal suspensions and the related gels (solid colloidal systems) are of interest because many of them have fundamentally useful properties. Natural systems such as milk, the interior of cells, even atmospheric fog are colloidal systems. Synthetic colloids exist in coatings, cosmetics, and elsewhere.Understanding colloids could lead to a deeper understanding of complex soft matter, with implications for new or improved materials and polymer science, but we have only an incomplete picture of the structure and dynamics of colloidal suspensions.(Etc…)

Working with high-brightness x-rays from the U.S. Department of Energy Office of Science’s Advanced Photon Source (APS) at Argonne, the research team used the new synchrotron x-ray technique called ultra-small-angle x-ray scattering (USAXS)–x-ray photon correlation spectroscopy (XPCS) to help them see through colloidal systems in order to reveal inner secrets. This new technique, implemented on the dedicated USAXS beamline (initially the X-ray Science Division 32-ID beamline, and later the ChemMatCARS 15-ID beamline) at the APS, overcomes the problem of attempting to use light to study such opaque systems because the wavelengths of x-rays are so much shorter than that of visible light and so can resolve details of the  involved and their behavior on concomitantly shorter length scales.

Rather than the apparently simple Brownian motion taking place in this , it seems that the microspheres move collectively, whereby buffeted particles pull along their neighbors. Such behavior implies that, compared with expectations, the suspended particles spend much longer times in close proximity without touching. Potentially, this behavior could be exploited in cases where suspended particles serve as centers for chemical reactions.

Nova Linha de Pesquisa: Biologia, Doenças, Proteínas, Anti-corpos

quinta-feira, dezembro 19th, 2013

Medpage Today

Lab Notes: Camels, Coffee, Beer, and Probiotics


Camels to the Rescue for Arthritis?

A novel single domain antibody derived from alpacas — a New World species of camelid — significantly reduced cartilage erosion and inflammatory cell infiltration in two mouse models of rheumatoid arthritis, Chinese researchers reported in Arthritis Research & Therapy.

The antibody targets the intracellular protein cyclophilin A, which has been implicated in the pathogenesis of rheumatoid arthritis through its recruitment of macrophages, monocytes, and matrix metalloproteinases into the synovium and joint. Camelids produce a unique type of antibody that consists exclusively of heavy chains, and the derived anti-cyclophylin can be easily and inexpensively produced, unlike most conventional antibodies.

In a series of experiments, the researchers injected arthritic mice with the antibody sdAbA1, and found significantly lower clinical and radiographic scores for hind paw arthritis. They also observed that treatment with sdAbA1 provided even greater decreases in inflammatory cells than administration of the widely used tumor necrosis factor inhibitor infliximab(Remicade). This antibody may represent a new therapeutic target for rheumatoid arthritis for patients who don’t respond to the available agents, they concluded.

— Nancy Walsh

Coffee Ages Cells

But a glass of beer might have the opposite effect, according to a study of telomeres in yeast cells.

The length of these end caps on chromosomal DNA, which determine how many times a cell can replicate with implications for both aging and cancer, grew when cells were exposed to alcohol or vinegar but shortened with caffeine or high temperatures.

Oxidative stress and a number of other environmental stresses tested had no impact on telomeres, Martin Kupiec, PhD, of Israel’s Tel Aviv University and colleagues reported inPLOS Genetics.

“For the first time we’ve identified a few environmental factors that alter telomere length, and we’ve shown how they do it,” Kupiec explained in a statement. “What we learned may one day contribute to the prevention and treatment of human diseases.”

— Crystal Phend

Probiotics for Autism?

Probiotic therapy eased both gastrointestinal and behavioral symptoms in a mouse model ofautism, according to a study in Cell.

Gastrointestinal symptoms are relatively common in individuals with autism spectrum disorders (ASDs), and Sarkis Mazmanian, PhD, of the California Institute of Technology, and colleagues explored whether alleviating the GI problems could have other effects in mice displaying some of the characteristics of autism.

The mice had intestinal permeability, and after ingesting Bacteroides fragilis, which has been used in animal experiments as a probiotic therapy, the permeability was corrected. At the same time, the mice had improved communication and reductions in anxiety and repetitive behaviors.

“Our findings reveal that gut bacteria can influence behavioral abnormalities relevant to neurodevelopmental disorders and raise the exciting possibility that certain probiotics may represent a novel approach to treating behavioral symptoms in humans,” Mazmanian said in a statement.

— Todd Neale

CD4/8+ Cell Counts Get Portable

Researchers at the University of Illinois in Urbana-Champaign are on track to develop a handheld point-of-care device for measuring CD4/8-positive cells in a drop of blood, according to their report in Science Translational Medicine. The technology could vastly simplify diagnosis of AIDS and monitoring antiretroviral therapy in patients with HIV infection.

Led by Rashid Bashir, PhD, the researchers have created prototype microfluidic biochips that process blood samples in five steps: chemically breaking down red cells, stopping the lysis to preserve leukocytes, counting cells electrically, stripping out CD4/8-positive cells with antibodies, and then counting the remaining cells. The result in preliminary tests has been counts of CD4/8-positive cell counts with accuracy similar to conventional clinical-lab assays.

However, the group indicated that more work needs to be done before the technology could be used clinically. Bashir and colleagues still need to package the biochips into a unitary, battery-powered instrument, as well as identify ways to standardize and manufacture the disposable modules needed for a commercially viable device.

— John Gever

Luz, Campos Magnéticos: Tema a Pesquisar

quinta-feira, dezembro 19th, 2013

Mystery Solved; Earth’s Deadly Radiation Belts Fueled By “Chorus” In Upper Atmosphere

Researchers may have found an explanation for the mysterious super-high energy particles that exist in the Earth’s upper atmosphere.

Van Allen Belts are rings of high-energy particles surrounding Earth.

Van Allen Belts are rings of high-energy particles surrounding Earth. (Photo : UCLA)