Evidence for alloy scattering from pressure-induced changes of electron mobility in In1?xGaxAsyP1?y

The electron mobility in the quaternary alloy In1?xGaxAsyP1?y has been measured at pressures up to 16 kbar which produce significant changes in the effective mass. Both the pressure dependence and the temperature dependence indicate that alloy scattering has a strong influence on the electron mobility.     

Effects of aurothioglucose on iron-induced rat liver microsomal lipid peroxidation

Aurothioglucose (ATG), an inhibitor of selenium-dependent glutathione peroxidase activity, at a concentration of 100 μM, strongly increases lipid peroxidation of rat liver microsomes exposed to either ferrous ion (10 μM) or the combination of ferric ion (10 μM) and ascorbic acid (500 μM), in the presence of reduced glutathione (GSH, 800 μM). This effect was not achieved using heat-inactivated microsomes and was dependent on the presence of GSH. ATG did not affect the lag period associated with ascorbic acid/ferric ion-induced microsomal lipid peroxidation (previously attributed to an undefined GSH-dependent microsomal agent), but did increase the rate of peroxidation subsequent to the lag period. The potent GSH-dependent inhibition of microsomal lipid peroxidation by cytosol (10% of total volume) was completely reversed by ATG (100 μM). ATG similarly reversed an inhibition of phosphatidyl-choline hydroperoxide-dependent liposomal peroxidation that has been attributed to phospholipid hydroperoxide glutathione peroxidase (PHGPX), an enzyme distinct from the classical glutathione that cannot utilize intact phospholipids. ATG inhibited, in addition to the classifical selenium-dependent glutathione peroxidase, both cytosolic and microsomal (basal and N-ethyl maleimide-stimulated) glutathione S-transferase activities with greater than 80% inhibition achieved at 100 μM ATG. ATG, at concentrations up to 250 μM, did not inhibit PHGPX activity measured by the coupled-enzyme method in the presence of Triton X-100 (0.1%). These data demonstrate the potential of ATG to increase toxicity of lipid peroxidative stimuli by inhibition of microsomal and cytosolic defense mechanisms. Although ATG did not inhibit Triton-enhanced PHGPX activity, overall evidence points toward inhibition of this enzyme as the mechanism for ATG-augmented lipid peroxidation and supports the conclusion that PHGPX plays a major role in the cellular defense mechanism.     

Effect of dietary protein restriction on nutritional status in the Modification of Diet in Renal Disease Study

The safety of dietary protein and phosphorous restriction was evaluated in the Modification of Diet in Renal Disease (MDRD) Study. In Study A, 585 patients with a glomerular filtration rate (GFR) of 25 to 55 ml/min/1.73 m2 were randomly assigned to a usual-protein diet (1.3 g/kg/day) or a low-protein diet (0.58 g/kg/day). In Study B, 255 patients with a GFR of 13 to 24 ml/min/1.73 m2 were randomly assigned to the low-protein diet or a very-low-protein diet (0.28 g/kg/day), supplemented with a ketoacid-amino acid mixture (0.28 g/kg/day). The low-protein and very-low-protein diets were also low in phosphorus. Mean duration of follow-up was 2.2 years in both studies. Protein and energy intakes were lower in the low-protein and very-low-protein diet groups than in the usual-protein group. Two patients in Study B reached a "stop point" for malnutrition. There was no difference between randomized groups in the rates of death, first hospitalizations, or other "stop points" in either study. Mean values for various indices of nutritional status remained within the normal range during follow-up in each diet group. However, there were small but significant changes from baseline in some nutritional indices, and differences between the randomized groups in some of these changes. In the low-protein and very-low-protein diet groups, serum albumin rose, while serum transferrin, body wt, percent body fat, arm muscle area and urine creatinine excretion declined. Combining patients in both diet groups in each study, a lower achieved protein intake (from food and supplement) was not correlated with a higher rate of death, hospitalization or stop points, or with a progressive decline in any of the indices of nutritional status after controlling for baseline nutritional status and follow-up energy intake. These analyses suggest that the low-protein and very-low-protein diets used in the MDRD Study are safe for periods of two to three years. Nonetheless, both protein and energy intake declined and there were small but significant declines in various indices of nutritional status. These declines are of concern because of the adverse effect of protein calorie malnutrition in patients with end-stage renal disease. Physicians who prescribe low-protein diets must carefully monitor patients' protein and energy intake and nutritional status.     

Effects of spousal control and support on older adults' recovery from knee surgery.

The authors investigated associations between spousal control (influence) and support on the recovery outcomes for 70 men and women (mean age = 70) undergoing an increasingly common surgical treatment for osteoarthritis (OA) of the knee. Spouses' positive (motivating) and negative (pressuring) control and spouses' emotional (understanding) and problematic (dismissing) support were examined as predictors of patients' adherence and improvement in well-being. Positive control was associated with better adherence, but only among patients whose spouses provided little problematic support. In contrast, negative control strategies tended to elicit increases in negative affect. Overall, our findings revealed that the effectiveness of spousal control depended largely on the quality of support provided by the spouse. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

CrO<Subscript>2</Subscript>/Ag/YBCO Interface Study with a Flip-Chip Configuration

Transport across a CrC₂/Ag/YBCO interface was studied using a flip-chip configuration. The results were interpreted in the Andreev reflection scenario. It is shown that the surface spinpolarization of CrO₂ film, even after exposing to air, remained close to 100% to theT _c of YBa₂Cu₃O_7−x , a temperature limited by this method.     

Measurement of Neutron Decay Parameters—The abBA Experiment

We are developing an experiment to measure the correlations a, A, and B, and the Fierz interference term b in neutron decay, with a precision of approximately 10⁻⁴. The experiment uses an electromagnetic spectrometer in combination with two large-area segmented silicon detectors to detect the proton and electron from the decay in coincidence, with 4π acceptance for both particles. For the neutron-polarization-dependent observables A and B, precision neutron polarimetry is achieved through the combination of a pulsed neutron beam, under construction at the SNS, and a polarized ³He neutron polarizer. Measuring a and A in the same apparatus provides a redundant determination of λ = g_A/g_V. Uncertainty in λ dominates the uncertainty of CKM unitarity tests.     

The Prejudicial Nature of Victim Impact Statements: Implications for Capital Sentencing Policy.

Victim impact evidence is presented during sentencing hearings to convey the harm experienced by victims and victims' relatives as a result of a crime. Its use in capital cases is highly controversial. Some argue that the Supreme Court's decision to allow the admission of victim impact statements (VIS) during capital sentencing proceedings (Payne v. Tennessee, 1991) invites prejudice and judgments based on emotion rather than reason. Others reason that it provides an important voice for survivors and affords the jury an opportunity to learn about the victim. The authors outline the chief psychological issues that arise in the context of VIS, including their relevance to jurors' judgments of blameworthiness, concerns that the social worth of the victim will influence jurors' sentencing decisions, and issues related to the emotional appeal of VIS. Psycholegal research on the influence of VIS on mock jurors is reviewed, and implications of this work for capital sentencing policy and suggested directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The preparation and characterization of crystals of the superconducting polymer, (SN)x

A technique is described for growing (SN)_x crystals which have superior electrical properties to those reported previously. The room temperature electrical conductivity has increased, so has the ratio of the room temperature and 4°K resistivities. There is no conductivity maximum in the region 20–30°K and the superconducting transition temperature is higher.     

Progress towards magnetic trapping of ultra-cold neutrons

We report progress towards magnetic trapping of ultra-cold neutrons (UCN) in preparation for a neutron lifetime measurement. UCN will be produced by inelastic scattering of cold (0.89 nm) neutrons in a reservoir of superfluid ⁴He and confined in a three-dimensional magnetic trap. As the trapped neutrons decay, recoil electrons will generate scintillations in the liquid He, which should be detectable with nearly 100% efficiency. This direct measure of the number of UCN decays vs. time can be used to determine the neutron beta-decay lifetime.