1,570 research outputs found
Equation of state for the MCFL phase and its implications for compact star models
Using the solutions of the gap equations of the magnetic-color-flavor-locked
(MCFL) phase of paired quark matter in a magnetic field, and taking into
consideration the separation between the longitudinal and transverse pressures
due to the field-induced breaking of the spatial rotational symmetry, the
equation of state (EoS) of the MCFL phase is self-consistently determined. This
result is then used to investigate the possibility of absolute stability, which
turns out to require a field-dependent bag constant to hold. That is, only if
the bag constant varies with the magnetic field, there exists a window in the
magnetic field vs. bag constant plane for absolute stability of strange matter.
Implications for stellar models of magnetized (self-bound) strange stars and
hybrid (MCFL core) stars are calculated and discussed.Comment: 11 pp. 11 figure
PBP4: A New Perspective on Staphylococcus aureus β-Lactam Resistance.
β-lactam antibiotics are excellent drugs for treatment of staphylococcal infections, due to their superior efficacy and safety compared to other drugs. Effectiveness of β-lactams is severely compromised due to resistance, which is widespread among clinical strains of Staphylococcus aureus. β-lactams inhibit bacterial cells by binding to penicillin binding proteins (PBPs), which perform the penultimate steps of bacterial cell wall synthesis. Among PBPs of S. aureus, PBP2a has received the most attention for the past several decades due to its preeminent role in conferring both high-level and broad-spectrum resistance to the entire class of β-lactam drugs. Studies on PBP2a have thus unraveled incredible details of its mechanism of action. We have recently identified that an uncanonical, low molecular weight PBP of S. aureus, PBP4, can also provide high-level and broad-spectrum resistance to the entire class of β-lactam drugs at a level similar to that of PBP2a. The role of PBP4 has typically been considered not so important for β-lactam resistance of S. aureus, and as a result its mode of action remains largely unknown. In this article, we review our current knowledge of PBP4 mediating β-lactam resistance in S. aureus
Modeling cancer metabolism on a genome scale
Cancer cells have fundamentally altered cellular metabolism that is associated with their tumorigenicity and malignancy. In addition to the widely studied Warburg effect, several new key metabolic alterations in cancer have been established over the last decade, leading to the recognition that altered tumor metabolism is one of the hallmarks of cancer. Deciphering the full scope and functional implications of the dysregulated metabolism in cancer requires both the advancement of a variety of omics measurements and the advancement of computational approaches for the analysis and contextualization of the accumulated data. Encouragingly, while the metabolic network is highly interconnected and complex, it is at the same time probably the best characterized cellular network. Following, this review discusses the challenges that genome‐scale modeling of cancer metabolism has been facing. We survey several recent studies demonstrating the first strides that have been done, testifying to the value of this approach in portraying a network‐level view of the cancer metabolism and in identifying novel drug targets and biomarkers. Finally, we outline a few new steps that may further advance this field
Immuno-virological and toxicity outcomes of HIV-infected patients after 48 months of ART in Phnom Penh, Cambodia
Mexico AIDS Conference 200
Natural Entropy Production in an Inflationary Model for a Polarized Vacuum
Though entropy production is forbidden in standard FRW Cosmology, Berman and
Som presented a simple inflationary model where entropy production by bulk
viscosity, during standard inflation without ad hoc pressure terms can be
accommodated with Robertson-Walker's metric, so the requirement that the early
Universe be anisotropic is not essential in order to have entropy growth during
inflationary phase, as we show. Entropy also grows due to shear viscosity, for
the anisotropic case. The intrinsically inflationary metric that we propose can
be thought of as defining a polarized vacuum, and leads directly to the desired
effects without the need of introducing extra pressure terms.Comment: 7 pages including front one. Accepted to publication, Astrophysics
and Space Science, subjected to a minor correction, already submitte
Effect of thermal annealing on the structure and microstructure ofTiO2 thin films
Nanostructured TiO2 thin films have been prepared through chemical route
using sol-gel and spin coating techniques. The deposited films were annealed in the
temperature range 400–1000°C for 1 h. The structure and microstructure of the
annealed films were characterized by GAXRD, micro-Raman spectroscopy and AFM. The
as-deposited TiO2 thin films are found to be amorphous. Micro-Raman and GAXRD
results confirm the presence of the anatase phase and absence of the rutile phase
for films annealed up to 700°C. The diffraction pattern of the film annealed at 800
to 1000°C contains peaks of both anatase and rutile reflections. The intensity of
all peaks in micro-Raman and GAXRD patterns increased and their width (FWHM)
decreased with increasing annealing temperature, demonstrating the improvement in
the crystallinity of the annealed films. Phase transformation at higher annealing
temperature involves a competition among three events such as : grain growth of
anatase phase, conversion of anatase to rutile and grain growth of rutile phase. AFM
image of the as-deposited films and annealed films indicated exponential grain
growth at higher temperature.Effect of thermal annealing on the structure and microstructure ofTiO2 thin films
Haripriya Rath1*, S Anand2, M Mohapatra2, Priyadarshini Dash1, T Som3,
U P Singh4 and N C Mishra1
1Department of Physics, Utkal University, Bhubaneswar-751 004, Orissa, India
2Institute of Minerals and Materials Technology, Bhubaneswar-751 013, Orissa, India
3Institute of Physics, Bhubaneswar-751 005, Orissa, India
4KIIT University, Bhubaneswar-751 024, Orissa, India
E-mail : [email protected] of Physics, Utkal University, Bhubaneswar-751 004, Orissa, India
2Institute of Minerals and Materials Technology, Bhubaneswar-751 013, Orissa, India
3Institute of Physics, Bhubaneswar-751 005, Orissa, India
4KIIT University, Bhubaneswar-751 024, Orissa, India
1Department of Physics, Utkal University, Bhubaneswar-751 004, Orissa, India
2Institute of Minerals and Materials Technology, Bhubaneswar-751 013, Orissa, India
3Institute of Physics, Bhubaneswar-751 005, Orissa, India
4KIIT University, Bhubaneswar-751 024, Orissa, Indi
Oxidation mechanism in metal nanoclusters: Zn nanoclusters to ZnO hollow nanoclusters
Zn nanoclusters (NCs) are deposited by Low-energy cluster beam deposition
technique. The mechanism of oxidation is studied by analysing their
compositional and morphological evolution over a long span of time (three
years) due to exposure to ambient atmosphere. It is concluded that the
mechanism proceeds in two steps. In the first step, the shell of ZnO forms over
Zn NCs rapidly up to certain limiting thickness: with in few days -- depending
upon the size -- Zn NCs are converted to Zn-ZnO (core-shell), Zn-void-ZnO, or
hollow ZnO type NCs. Bigger than ~15 nm become Zn-ZnO (core-shell) type: among
them, NCs above ~25 nm could able to retain their initial geometrical shapes
(namely triangular, hexagonal, rectangular and rhombohedral), but ~25 to 15 nm
size NCs become irregular or distorted geometrical shapes. NCs between ~15 to 5
nm become Zn-void-ZnO type, and smaller than ~5 nm become ZnO hollow sphere
type i.e. ZnO hollow NCs. In the second step, all Zn-void-ZnO and Zn-ZnO
(core-shell) structures are converted to hollow ZnO NCs in a slow and gradual
process, and the mechanism of conversion proceeds through expansion in size by
incorporating ZnO monomers inside the shell. The observed oxidation behaviour
of NCs is compared with theory of Cabrera - Mott on low-temperature oxidation
of metal.Comment: 9 pages, 8 figure
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