Preexercise meal composition alters plasma large neutral amino acid responses during exercise and recovery

This study was designed to determine metabolic and physical performance responses to ingestion of pre-exercise meals with different macronutrient and fiber profiles. Twelve physically active subjects (6 males and 6 females) were used to investigate the metabolic and physical performance consequences of consuming pre-exercise meals consisting of oat, corn, or wheat cereals. A fasting trial served as the control, and all subjects received each treatment in a Latin-square design. Blood samples were drawn before and 85 min after meal ingestion, during 90 min of cycling exercise (60% VO2peak), after a 6.4 km performance ride, and during 60 min of recovery. Expired air samples were collected to determine nutrient utilization. Resting carbohydrate oxidation rates and plasma insulin concentrations after oat ingestion were less than after wheat, and corn and wheat ingestion, respectively (P < 0.05). During exercise, the change in plasma glucose from pre-exercise was greater after consuming wheat and corn compared with oat (P < 0.05), and it was inversely related to pre-exercise plasma insulin concentration (r = -0.55, P = 0.0001). Plasma free fatty acid concentrations were inversely related to plasma lactate concentrations (r = -0.58, P = 0.0001). Free fatty acid concentrations and fat oxidation were greater in fasting trials than all others, but performance ride times did not differ among treatments. Plasma branched-chain amino acid concentrations resembled their respective meal profiles throughout exercise, the performance ride, and recovery. These results indicate that pre-exercise meal composition can influence glucose homeostasis during early exercise and plasma branched-chain amino acid concentrations over a substantial range of metabolic demands.     

Examination of coping resources and family adaptation in mothers and daughters of incestuous versus nonclinical families.

Mother–daughter dyads from incestuous vs nonclinical families were compared in terms of (1) family life stress, (2) problem-solving appraisal, (3) direct coping behaviors, (4) mother–daughter communication, and (5) family adaptation and cohesion. 15 mother–daughter pairs from an incestuous family involving an adult male caretaker were matched on several variables to 16 mother–daughter pairs from a nonclinical family. The results revealed that mothers from the incest group (compared with the nonclinical group) reported greater amounts of family life stress, had more negative perceptions of their problem-solving appraisal, and reported more communication difficulties. The daughters from the incest group appeared to be quite similar to the nonclinical group daughters, although they did acknowledge more family stress. Implications of the results for therapeutic interventions as well as future research were discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Superior activity of a thromboxane receptor antagonist as compared with aspirin in rat models of arterial and venous thrombosis

We determined the effects of aspirin and a novel thromboxane A2/prostaglandin endoperoxide (TP)-receptor antagonist, BMS-180291, on thrombosis and bleeding times in skin and mesenteric arteries. In anesthetized rats, occlusive thrombosis was induced in the carotid artery by topical application of ferrous chloride and in the vena cava by blood flow stasis combined with either infusion of thromboplastin or hypotonic saline. Aspirin (1, 10, and 50 mg/kg) did not reduce arterial or venous thrombus weight significantly. BMS 180,291 (150 micrograms/kg/min) decreased arterial thrombus weight and hypotonic saline-induced caval thrombus weight by 58 and 57%, respectively. BMS-180291 lacked antithrombotic activity at a lower dose (50 micrograms/kg/min) and failed to inhibit thromboplastin-induced caval thrombosis. BMS-180291 (150 micrograms/kg/min) significantly reduced arterial thrombus weight by 40% when plasma epinephrine concentration was increased to 5 ng/ml. BMS-180291 and aspirin produced increases of only < or = 30% in bleeding times. These results demonstrate that BMS-180291 has antithrombotic activity in experimental aspirin-resistant arterial and venous thrombosis. Both aspirin and BMS-180291 have only modest effects on small artery hemostasis in rats.     

PRA as a management tool: organizational factors and risk-based priorities for the maintenance of the tiles of the space shuttle orbiter

A probabilistic risk assessment (PRA) model, developed for the Thermal Protection System (TPS) of the space shuttle orbiter and presented in the previous paper, is used as a management tool to identify root-cause, organizational factors of the various failure modes. The objective is to set priorities in the process of resource allocation to minimize the risk of accident caused by the failure of the TPS. Starting with the technical characteristics of the system and the inputs of the risk assessment model, the approach is to identify the human decisions and actions and the key organizational factors that influence the risk.

Among the management factors that affect the reliability of the TPS are time pressures that have occurred in the past, liability concerns and conflicts among contractors, the low status of the tile work and material technicians among maintenance personnel, the absence of priorities in tile testing, and under-recognized couplings among subsystems (such as the external tank insulation as a source of debris that may hit the tiles). It is shown here how using the PRA results to set priorities in the maintenance of the tiles can allow reduction of the overall risk, and how critical zones of debris sources can be identified on the surface of the external tank and the solid rocket booster. It was found, for instance, that detecting and fixing loose tiles in the most risk-critical areas and securing insulation by up to 80%, and securing the insulation of external systems in specified areas could reduce the TPS risk by about 75%.     

Plasma immersion ion implantation for SOI synthesis: SIMOX and ion-cut

We have demonstrated feasibility to form silicon-on-insulator (SOI) substrates using plasma immersion ion implantation (PIII) for both separation by implantation of oxygen and ion-cut. This high throughput technique can substantially lower the high cost of SOI substrates due to the simpler implanter design as well as ease of maintenance. For separation by plasma implantation of oxygen wafers, secondary ion mass spectrometry analysis and cross-sectional transmission electron micrographs show continuous buried oxide formation under a single-crystal silicon overlayer with sharp Si/SiO₂ interfaces after oxygen plasma implantation and high-temperature (1300°C) annealing. Ion-cut SOI wafer fabrication technique is implemented for the first time using PIII. The hydrogen plasma can be optimized so that only one ion species is dominant in concentration and there are minimal effects by other residual ions on the ion-cut process. The physical mechanism of hydrogen induced silicon surface layer cleavage has been investigated. An ideal gas law model of the microcavity internal pressure combined with a two-dimensional finite element fracture mechanics model is used to approximate the fracture driving force which is sufficient to overcome the silicon fracture resistance.     

Meta-analyses of age–cognition relations in adulthood: Estimates of linear and nonlinear age effects and structural models.

A meta-analysis was conducted on 91 studies to derive a correlation matrix for adult age, speed of processing, primary–working memory, episodic memory, reasoning, and spatial ability. Structural equation modeling with a single latent common cognitive factor showed that all cognitive measures shared substantial portions of age-related variance. A mediational model revealed that speed of processing and primary–working memory appear to be important mediators of age-related differences in the other measures. However, not all of the age-related influences were mediated. An examination of quadratic age effects and correlational patterns for subsamples under and over 50 years of age revealed that (a) negative age–cognition relations were significant for the 18- to 50-year-old sample and (b) the age-related decline accelerated significantly over the adult life span for variables assessing speed, reasoning, and episodic memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accuracy and stability improvements of integral equation modelsusing the partial element equivalent circuit (PEEC) approach

The partial element equivalent circuit (PEEC) technique is a formulation which transforms an electric field integral equation (EFIE) into a full-wave equivalent circuit solution. In this paper, improvements are made to the PEEC model through the development of a refined method of computing both the partial inductances as well as the coefficients of potential. The method does not increase the number of unknowns. In addition, damping is added to the PEEC model in order to further reduce nonphysical resonances which may occur above the useful frequency range, The observations and solutions presented in this paper are especially important for time domain solvers. The effectiveness of the method is illustrated with several examples