2,115 research outputs found
Density Of States And Energy Spectra Of Hydrogenic Impurities In Quantum-well Wires
We calculate binding energies and densities of states of hydrogenic impurities in quantum-well wires with rectangular cross sections using a variational procedure within the effective-mass approximation. Calculations were performed as functions of the position of the impurity in a quantum-well wire of infinite depth and for various sizes of the wire cross section. The center of gravity of the impurity band and the density of impurity states are analyzed and compared with their quantum-well counterparts, with similarities as well as differences being discussed. Our results indicate that a proper consideration of the density of impurity states may be of relevance in the interpretation of future experimental data related to shallow impurities in quantum-well wires. © 1988 The American Physical Society.3832179218
The Molecular Basis of Selective Permeability of Connexins is Complex and Includes Both Size And Charge
Although gap junction channels are still widely viewed as large, non-specific pores connecting cells, the diversity in the connexin family has led more attention to be focused on their permeability characteristics. We summarize here the current status of these investigations, both published and on-going, that reveal both charge and size selectivity between gap junction channels composed of different connexins. In particular, this review will focus on quantitative approaches that monitor the expression level of the connexins, so that it is clear that differences that are seen can be attributed to channel properties. The degree of selectivity that is observed is modest compared to other channels, but is likely to be significant for biological molecules that are labile within the cell. Of particular relevance to the in vivo function of gap junctions, recent studies are summarized that demonstrate that the connexin phenotype can control the nature of the endogenous traffic between cells, with consequent effects on biological effects of gap junctions such as tumor suppression
Hydrolyzed Feather meal Supplementation for Lactating Range Cows
A 2-year study involving 178 cow/calf pairs was conducted to evaluate hydrolyzed feather meal4 as a protein supplement for cows grazing native range during early lactation. Calving season occurred from mid-March until late April. Within a week after calving, cows were fed either a soybean meal or feather meal-corn supplement that provided approximately .83 1b crude protein per cow daily. Cow weight and condition score changes from calving until early May and percentage of cows cycling early in the breeding season (early June) were similar between supplement groups. Calf average daily gains from birth until May were not affected by supplement fed to cows. In this study, supplementing lactating cows with hydrolyzed feather meal resulted in similar performance, regardless of cow age, as supplementing with soybean meal
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Testing of optical diagnostics for ion-beam-driven WDM experiments at NDCX-1
We report on the testing of optical diagnostics developed for warm-dense-matter (WDM) experiments on the Neutralized Drift Compression Experiments (NDCX-1) at Lawrence Berkeley National Laboratory (LBNL). The diagnostics consist of a fast optical pyrometer, a streak camera spectrometer, and a VISAR.While the NDCX is in the last stage of commissioning for the target experiments, the diagnostics were tested elsewhere in an experiment where an intense laser pulse was used to generate the WDM state in metallic and carbon samples
Prolapse severity, symptoms and impact on quality of life among women planning sacrocolpopexy
Objectives: To explore the relationship between severity of pelvic organ prolapse (POP), symptoms of pelvic dysfunction and quality of life using validated measures. Method: Baseline data from 314 participants in the Colpopexy And Urinary Reduction Efforts (CARE) trial were analyzed. Pelvic symptoms and impact were assessed using the Pelvic Floor Distress Inventory (PFDI) and the Pelvic Floor Impact Questionnaire (PFIQ). PFDI and PFIQ scores were compared by prolapse stage and history of incontinence or POP surgery. Regression analyses were performed to identify other predictors of symptoms and impact. Results: Women were predominantly (90%) Caucasian and had mean age of 61 years. Women with stage II POP, especially those with prior surgery, reported more symptoms and impact than women with more advanced POP. There were no other significant predictors of symptoms or life impact. Conclusions: Women planning sacrocolpopexy with stage II prolapse and prior pelvic surgery reported more symptoms and quality of life impact than those with more advanced prolapse.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135603/1/ijgo24.pd
A Study Of Human T-Cell Lines Generated From Multiple Sclerosis Patients And Controls By Stimulation With Peptides Of Myelin Basic Protein
We generated T-cell lines from the peripheral blood of controls and of patients with multiple sclerosis (MS) by stimulation with overlapping synthetic peptides representing the entire sequences of all four isoforms of human myelin basic protein (MBP). The T-cell lines reacted to a wide range of epitopes in the major isoforms of MBP and to epitopes that were present only in the minor isoforms. Many MS patients and controls had T-cells responding to one or more cryptic MBP epitopes, as indicated by the generation of a peptide-specific T-cell line(s) by stimulation with synthetic peptides but not by stimulation with whole MBP. About one-third of the peptide-generated lines were cytotoxic. Although we have shown that this technique of peptide stimulation is effective in generating human antiviral cytotoxic CD8+ T-cell lines, all the cytotoxic MBP-specific lines generated by this method were predominantly CD4+. Our study did not reveal any significant differences, between MS patients and controls, in reactivity to epitopes within any of the isoforms of MBP
Finite temperature scaling theory for the collapse of Bose-Einstein condensate
We show how to apply the scaling theory in an inhomogeneous system like
harmonically trapped Bose condensate at finite temperatures. We calculate the
temperature dependence of the critical number of particles by a scaling theory
within the Hartree-Fock approximation and find that there is a dramatic
increase in the critical number of particles as the condensation point is
approached.Comment: Published online [6 pages, 3 figures
Raman scattering studies of spin, charge, and lattice dynamics in Ca_{2-x}Sr_{x}RuO_{4} (0 =< x < 0.2)
We use Raman scattering to study spin, charge, and lattice dynamics in
various phases of Ca_{2-x}Sr_{x}RuO_{4}. With increasing substitution of Ca by
Sr in the range 0 =< x < 0.2, we observe (1) evidence for an increase of the
electron-phonon interaction strength, (2) an increased temperature-dependence
of the two-magnon energy and linewidth in the antiferromagnetic insulating
phase, and (3) evidence for charge gap development, and hysteresis associated
with the structural phase change, both of which are indicative of a first-order
metal-insulator transition (T_{MI}) and a coexistence of metallic and
insulating components for T < T_{MI}
Statistical Survey of Type III Radio Bursts at Long Wavelengths Observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves Instruments: Radio Flux Density Variations with Frequency
We have performed a statistical study of Type III radio bursts observed
by Solar TErrestrial RElations Observatory (STEREO)/Waves between May 2007 and
February 2013. We have investigated the flux density between kHz and
MHz. Both high- and low-frequency cutoffs have been observed in of
events suggesting an important role of propagation. As already reported by
previous authors, we observed that the maximum flux density occurs at MHz on
both spacecraft. We have developed a simplified analytical model of the flux
density as a function of radial distance and compared it to the STEREO/Waves
data.Comment: published in Solar Physic
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