244 research outputs found
Invasive Actinomycosis of Maxilla - An Unusual Case Report
Cervicofacial actinomycosis is an unusual infection caused by Actinomyces species. It rarely involves the maxilla. We present a case of an elderly female with a left sided maxillary swelling which was diagnosed as left maxillary actinomycosis invading the adjacent structures suspected to be secondary to a bone neoplasm on the basis of histopathology. The organism grew in
culture in our laboratory and hence this case is a deviation from the common feature that cultures are most of the times of little help in detecting this organism. The classical growth of this organism on culture in addition to the histopathology report highly
empowered the diagnosis of this case. Also, our findings that it can permeate the surrounding structures and can produce a conundrum for the diagnosis are noteworthy
Phase Field Model for Three-Dimensional Dendritic Growth with Fluid Flow
We study the effect of fluid flow on three-dimensional (3D) dendrite growth
using a phase-field model on an adaptive finite element grid. In order to
simulate 3D fluid flow, we use an averaging method for the flow problem coupled
to the phase-field method and the Semi-Implicit Approximated Projection Method
(SIAPM). We describe a parallel implementation for the algorithm, using Charm++
FEM framework, and demonstrate its efficiency. We introduce an improved method
for extracting dendrite tip position and tip radius, facilitating accurate
comparison to theory. We benchmark our results for two-dimensional (2D)
dendrite growth with solvability theory and previous results, finding them to
be in good agreement. The physics of dendritic growth with fluid flow in three
dimensions is very different from that in two dimensions, and we discuss the
origin of this behavior
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Optimization of azimuthal uniformity of thermal conductance between AI TMP and Si cooling arms
Tunable intervalence charge transfer in ruthenium Prussian blue analogue enables stable and efficient biocompatible artificial synapses
Emerging concepts for neuromorphic computing, bioelectronics, and
brain-computer interfacing inspire new research avenues aimed at understanding
the relationship between oxidation state and conductivity in unexplored
materials. Here, we present ruthenium Prussian blue analogue (RuPBA), a mixed
valence coordination compound with an open framework structure and ability to
conduct both ionic and electronic charge, for flexible artificial synapses that
reversibly switch conductance by more than four orders of magnitude based on
electrochemically tunable oxidation state. Retention of programmed states is
improved by nearly two orders of magnitude compared to the extensively studied
organic polymers, thus reducing the frequency, complexity and energy costs
associated with error correction schemes. We demonstrate dopamine detection
using RuPBA synapses and biocompatibility with neuronal cells, evoking
prospective application for brain-computer interfacing. By application of
electron transfer theory to in-situ spectroscopic probing of intervalence
charge transfer, we elucidate a switching mechanism whereby the degree of mixed
valency between N-coordinated Ru sites controls the carrier concentration and
mobility, as supported by DFT
Fusion Energy Output Greater than the Kinetic Energy of an Imploding Shell at the National Ignition Facility
A series of cryogenic, layered deuterium-tritium (DT) implosions have produced, for the first time, fusion energy output twice the peak kinetic energy of the imploding shell. These experiments at the National Ignition Facility utilized high density carbon ablators with a three-shock laser pulse (1.5 MJ in 7.5 ns) to irradiate low gas-filled (0.3 mg/cc of helium) bare depleted uranium hohlraums, resulting in a peak hohlraum radiative temperature ∼290 eV. The imploding shell, composed of the nonablated high density carbon and the DT cryogenic layer, is, thus, driven to velocity on the order of 380 km/s resulting in a peak kinetic energy of ∼21 kJ, which once stagnated produced a total DT neutron yield of 1.9×10¹⁶ (shot N170827) corresponding to an output fusion energy of 54 kJ. Time dependent low mode asymmetries that limited further progress of implosions have now been controlled, leading to an increased compression of the hot spot. It resulted in hot spot areal density (ρr∼0.3 g/cm²) and stagnation pressure (∼360 Gbar) never before achieved in a laboratory experiment
C-ME: A 3D Community-Based, Real-Time Collaboration Tool for Scientific Research and Training
The need for effective collaboration tools is growing as multidisciplinary proteome-wide projects and distributed research teams become more common. The resulting data is often quite disparate, stored in separate locations, and not contextually related. Collaborative Molecular Modeling Environment (C-ME) is an interactive community-based collaboration system that allows researchers to organize information, visualize data on a two-dimensional (2-D) or three-dimensional (3-D) basis, and share and manage that information with collaborators in real time. C-ME stores the information in industry-standard databases that are immediately accessible by appropriate permission within the computer network directory service or anonymously across the internet through the C-ME application or through a web browser. The system addresses two important aspects of collaboration: context and information management. C-ME allows a researcher to use a 3-D atomic structure model or a 2-D image as a contextual basis on which to attach and share annotations to specific atoms or molecules or to specific regions of a 2-D image. These annotations provide additional information about the atomic structure or image data that can then be evaluated, amended or added to by other project members
Linking the dust and chemical evolution: Taurus and Perseus -- New collisional rates for HCN, HNC, and their C, N, and H isotopologues
HCN, HNC, and their isotopologues are ubiquitous molecules that can serve as
chemical thermometers and evolutionary tracers to characterize star-forming
regions. Despite their importance in carrying information that is vital to
studies of the chemistry and evolution of star-forming regions, the collision
rates of some of these molecules have not been available for rigorous studies
in the past. We perform an up-to-date gas and dust chemical characterization of
two different star-forming regions, TMC 1-C and NGC 1333-C7, using new
collisional rates of HCN, HNC, and their isotopologues. We investigated the
possible effects of the environment and stellar feedback in their chemistry and
their evolution. With millimeter observations, we derived their column
densities, the C and N isotopic fractions, the isomeric ratios, and the
deuterium fractionation. The continuum data at 3 mm and 850 m allowed us
to compute the emissivity spectral index and look for grain growth as an
evolutionary tracer. The HCN/HNC ratio is anticorrelated with the
deuterium fraction of HCN, thus it can readily serve as a proxy for the
temperature. The spectral index shows a tentative
anticorrelation with the HCN/HNC ratio, suggesting grain growth
in the evolved, hotter, and less deuterated sources. Unlike TMC 1-C, the
south-to-north gradient in dust temperature and spectral index observed in NGC
1333-C7 suggests feedback from the main NGC 1333 cloud. With this up-to-date
characterization of two star-forming regions, we found that the chemistry and
the physical properties are tightly related. The dust temperature, deuterium
fraction, and the spectral index are complementary evolutionary tracers. The
large-scale environmental factors may dominate the chemistry and evolution in
clustered star-forming regions.Comment: 25 pages, 20 figure
Computer modelling of the plasma chemistry and plasma-based growth mechanisms for nanostructured materials
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National Ignition Facility Target Design and Fabrication
The current capsule target design for the first ignition experiments at the NIF Facility beginning in 2009 will be a copper-doped beryllium capsule, roughly 2 mm in diameter with 160-{micro}m walls. The capsule will have a 75-{micro}m layer of solid DT on the inside surface, and the capsule will driven with x-rays generated from a gold/uranium cocktail hohlraum. The design specifications are extremely rigorous, particularly with respect to interfaces, which must be very smooth to inhibit Rayleigh-Taylor instability growth. This paper outlines the current design, and focuses on the challenges and advances in capsule fabrication and characterization; hohlraum fabrication, and D-T layering and characterization
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Lessons from Two Years of Building Fusion Ignition Targets with the Precision Robotic Assembly Machine
The Precision Robotic Assembly Machine was developed to manufacture the small and intricate laser-driven fusion ignition targets that are being used in the world's largest and most energetic laser, the National Ignition Facility (NIF). The National Ignition Campaign (NIC) goal of using the NIF to produce a self-sustaining nuclear fusion burn with energy gain - for the first time ever in a laboratory setting - requires targets that are demanding in materials fabrication, machining, and assembly. We provide an overview of the design and function of the machine, with emphasis on the aspects that revolutionized how NIC targets are manufactured
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