867 research outputs found
Data management for JGOFS: Theory and design
The Joint Global Ocean Flux Study (JGOFS), currently being organized under the auspices of the Scientific Committee for Ocean Research (SCOR), is intended to be a decade long internationally coordinated program. The main goal of JGOFS is to determine and understand on a global scale the processes controlling the time-varying fluxes of carbon and associated biogenic elements in the ocean and to evaluate the related exchanges with the atmosphere, sea floor and continental boundaries. 'A long-term goal of JGOFS will be to establish strategies for observing, on long time scales, changes in ocean biogeochemical cycles in relation to climate change'. Participation from a large number of U.S. and foreign institutions is expected. JGOFS investigators have begun a set of time-series measurements and global surveys of a wide variety of biological, chemical and physical quantities, detailed process-oriented studies, satellite observations of ocean color and wind stress and modeling of the bio-geochemical processes. These experiments will generate data in amounts unprecedented in the biological and chemical communities; rapid and effortless exchange of these data will be important to the success of JGOFS
Inelastic Neutron scattering in CeSi_{2-x}Ga_x ferromagnetic Kondo lattice compounds
Inelastic neutron scattering investigation on ferromagnetic Kondo lattice
compounds belonging to CeSi_{2-x}Ga_{x}, x = 0.7, 1.0 and 1.3, system is
reported. The thermal evolution of the quasielastic response shows that the
Kondo interactions dominate over the RKKY interactions with increase in Ga
concentration from 0.7 to 1.3. This is related to the increase in k-f
hybridization with increasing Ga concentration. The high energy response
indicates the ground state to be split by crystal field in all three compounds.
Using the experimental results we have calculated the crystal field parameters
in all three compounds studied here.Comment: 12 Pages Revtex, 2 eps figures
The Electrical Conductivities of Liquid Alkali- Metal Amalgams.
It deals with the electrical conductivities of liquid alkali- metal amalgams@IAC
Development, Disease, and Regeneration of Tissues in the Dental-Craniofacial Complex
This article has no abstract
Reduction of light output of plastic scintillator tiles during irradiation at cold temperatures and in low-oxygen environments
The advent of the silicon photomultiplier has allowed the development of
highly segmented calorimeters using plastic scintillator as the active media,
with photodetectors embedded in the calorimeter, in dimples in the plastic. To
reduce the photodetector's dark current and radiation damage, the high
granularity calorimeter designed for the high luminosity upgrade of the CMS
detector at CERN's Large Hadron Collider will be operated at a temperature of
about -30C. Due to flammability considerations, a low oxygen
environment is being considered. However, the radiation damage to the plastic
scintillator during irradiation in this operating environment needs to be
considered. In this paper, we present measurements of the relative decrease of
light output during irradiation of small plastic scintillator tiles read out by
silicon photomultipliers. The irradiations were performed using a
source both to produce the tiles' light and as a source of
ionizing irradiation at dose rates of 0.3, 1.3, and Gy/hr, temperatures
of -30, -15, -5, and 0C, and with several different oxygen
concentrations in the surrounding atmosphere. The effect of the material used
to wrap the tile was also studied. Substantial temporary damage, which annealed
when the sample was warmed, was seen during the low-temperature irradiations,
regardless of the oxygen concentration and wrapping material. The relative
light loss was largest with 3M Enhanced Specular
Reflector Film wrapping and smallest with no wrapping, although due to the
substantially higher light yield with wrapping, the final light output is
largest with wrapping. The light loss was less at warmer temperatures. Damage
with oxygen was similar to that in standard atmosphere. Evidence of a
plateau in the radical density was seen for the 0C data
Hepatic Lipid Accumulation and Nrf2 Expression following Perinatal and Peripubertal Exposure to Bisphenol A in a Mouse Model of Nonalcoholic Liver Disease
Background: Exposure to chemicals during critical windows of development may re-program liver for increased risk of nonalcoholic fatty liver disease (NAFLD). Bisphenol A (BPA), a plastics component, has been described to impart adverse effects during gestational and lactational exposure. Our work has pointed to nuclear factor E2-related factor 2 (Nrf2) being a modulator of hepatic lipid accumulation in models of NAFLD.
Objectives: To determine if chemical exposure can prime liver for steatosis via modulation of NRF2 and epigenetic mechanisms.
Methods: Utilizing BPA as a model exposure, pregnant CD-1 mice were administered 25μg/kg/day role= presentation \u3e25μg/kg/day BPA via osmotic minipumps from gestational day 8 through postnatal day (PND)16. The offspring were weaned on PND21 and exposed to same dose of BPA via their drinking water through PND35. Tissues were collected from pups at week 5 (W5), and their littermates at week 39 (W39).
Results: BPA increased hepatic lipid content concomitant with increased Nrf2 and pro-lipogenic enzyme expression at W5 and W39 in female offspring. BPA exposure increased Nrf2 binding to a putative antioxidant response element consensus sequence in the sterol regulatory-element binding protein-1c (Srebp-1c) promoter. Known Nrf2 activators increased SREBP-1C promoter reporter activity in HepG2 cells. Methylated DNA immunoprecipitation-PCR and pyrosequencing revealed that developmental BPA exposure induced hypomethylation of the Nrf2 and Srebp-1c promoters in livers of W5 mice, which was more prominent in W39 mice than in others.
Conclusion: Exposure to a xenobiotic during early development induced persistent fat accumulation via hypomethylation of lipogenic genes. Moreover, increased Nrf2 recruitment to the Srebp-1c promoter in livers of BPA-exposed mice was observed. Overall, the underlying mechanisms described a broader impact beyond BPA exposure and can be applied to understand other models of NAFLD
MODULATORY EFFECTS OF DILTIAZEM ON INOTROPIC RESPONSES TO AMRINONE ON RABBIT ISOLATED ATRIA
Abstract: The effect of pretreatment with graded concentration of diltiazem on the inotropic responses to amrinone were studied on isolated atria of rabbit. The responses to amrinonc were modified by diltiazem in a biphasic manner; initial potentiation followed by inhibition. The potentiation is proposed to be due to synergistic rise in cytosolic calcium ion concentration by diltiazem and amrinone. The inhibition by diltiazem in higher concentration may be due to blockade of calcium ion innux and depletion of intracellular calcium ion from storage siles
Effect of Electron Energy Distribution Function on Power Deposition and Plasma Density in an Inductively Coupled Discharge at Very Low Pressures
A self-consistent 1-D model was developed to study the effect of the electron
energy distribution function (EEDF) on power deposition and plasma density
profiles in a planar inductively coupled plasma (ICP) in the non-local regime
(pressure < 10 mTorr). The model consisted of three modules: (1) an electron
energy distribution function (EEDF) module to compute the non-Maxwellian EEDF,
(2) a non-local electron kinetics module to predict the non-local electron
conductivity, RF current, electric field and power deposition profiles in the
non-uniform plasma, and (3) a heavy species transport module to solve for the
ion density and velocity profiles as well as the metastable density. Results
using the non-Maxwellian EEDF model were compared with predictions using a
Maxwellian EEDF, under otherwise identical conditions. The RF electric field,
current, and power deposition profiles were different, especially at 1mTorr,
for which the electron effective mean free path was larger than the skin depth.
The plasma density predicted by the Maxwellian EEDF was up to 93% larger for
the conditions examined. Thus, the non-Maxwellian EEDF must be accounted for in
modeling ICPs at very low pressures.Comment: 19 pages submitted to Plasma Sources Sci. Techno
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