Solving surface structures from normal incidence X-ray standing wave data

A program is provided to determine structural parameters of atoms in or adsorbed on surfaces by refinement of atomistic models towards experimentally determined data generated by the normal incidence X-ray standing wave (NIXSW) technique. The method employs a combination of Differential Evolution Genetic Algorithms and Steepest Descent Line Minimisations to provide a fast, reliable and user friendly tool for experimentalists to interpret complex multidimensional NIXSW data sets.

Program summary

Program title: NIXSW Planewave SolverCatalogue identifier: ADZE_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZE_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 16 874No. of bytes in distributed program, including test data, etc.: 1 631 874Distribution format: tar.gzProgramming language: Borland C++ Builder 5Computer: Any Windows CompatibleOperating system: Windows 2000 and XPRAM: <10 MBClassification: 7.4Nature of problem: Using NIXSW experimental data to calculate atomic positions of adsorbates.Restrictions: Data from substrates must have cubic, tetragonal or orthorhombic crystal structures i.e. with 90° between conventional cell axes.Running time: Seconds-minutes dependant on the number of plane waves and the number of atomic sites.     

Inductor Modeling in Wireless Links for Implantable Electronics

This paper describes the ac power dissipation of coils as well as their self-capacitance, self-resonant frequency, and quality factor Q. In the past, self-resonant frequency was rarely calculated during design because of the lack of suitable closed-form design equations. However, coils are widely used in biomedical applications as inductive links for both power and data, and the power transfer capacity and the data rate of inductive links are determined by the operating frequency of the coils. The maximum operating frequency is limited by the self-resonant frequency of the coil. We present here an analytical express for the optimal frequency of a coil in terms of the design parameters. By varying the design parameters, we can move the optimal frequency close to the operating frequency, thereby boosting the efficiency of the inductive link. We have verified the derivation experimentally and shown it to be useful in optimizing coil Index performance.     

Effect of yohimbine on nerve growth factor mRNA and protein levels in rat hippocampus

Activation of noradrenergic receptors has been shown to increase expression of nerve growth factor (NGF) gene in brain cells in vitro. The present studies were undertaken to determine if this stimulation was effective in vivo as well. Rats were administered the norepinephrine-releasing drug, yohimbine (YOH), and had their hippocampi assayed for NGF mRNA and protein at various times after the injection. It was found that yohimbine caused a 3-fold increase of NGF mRNA levels at 24 h. Protein levels, however, were unaltered at this time. Thus norepinephrine release in vivo appears to be sufficient for increasing mRNA level but not for translation to protein.     

Chronic and acute prenatal and postnatal ethanol exposure on lymphocyte subsets from offspring thymic, splenic, and intestinal intraepithelial sources

The overall objective of this study was to analyze the effects of a combined prenatal and postnatal (entire gestational human chronic drinking model) ethanol exposure on T-cell development in mice. Specifically, this study evaluated the effects of chronic exposure to prenatal ethanol on lymphocyte makeup and proliferative capabilities of postnatal offspring's (4 and 12 weeks) peripheral lymphoid tissues. Chronic exposure regimens were conducted over the entire gestational period and through postnatal day 14 or 21. Thymus, spleen, and intestinal intraepithelial lymphocytes were harvested and analyzed by flow cytometry for percentages of T-cell subsets. Splenic lymphocytes were also analyzed for their ability to proliferate in response to a T-cell mitogen. Limited effects of chronic ethanol exposure were seen.     

Effects of maternal age on parenting role.

Examined the proposition that maternal age influences parental role performance and satisfaction. Mothers, ranging in age from 16 to 38 yrs, comprised 53 full-term and 52 preterm dyads. Perceptions of parenting role were assessed 1 mo after hospital discharge of infancts using the Satisfaction with Parenting Scale; interactive behaviors were observed when infants were 4 mo old. When other demographic factors and psychosocial variables were controlled, increased maternal age was significantly related to greater satisfaction with parenting, to greater time commitment to that role, and to more optimal observed behavior. Effects of maternal age on observed behavior were stronger in the term sample, whereas effects of maternal age on role satisfaction were stronger in the preterm group. Results indicate that maternal age should be accounted for in studies of mother–infant interaction and child outcomes; the suggestion of linear age effects argues against popular beliefs that adolescent and late childbearing represent unique categories of risk for poor parenting outcomes. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrolyte infiltration in phosphazene-based dye-sensitized solar cells

We report here a study of phosphazene polymer and oligomer electrolyte infiltration into high surface area titanium dioxide electrodes and its effect on the performance of dye-sensitized solar cells. The effects of different cell assembly procedures on the electrochemical properties are examined, as well as the infiltration of electrolytes based on poly[bis(2-(2-methoxyethoxy)ethoxy)phosphazene] (MEEP), hexakis(2-(2-methoxyethoxy)ethoxy)cyclotriphosphazene (MEE trimer), and a linear short chain analogue into conventional titanium dioxide electrode mesoporous (nanosphere) films, microcolumns and nanowires. The effects of temperature, co-solvents, and the order of addition of the electroactive components are found to affect both the conductivity of the electrolytes and the electrochemical performance of the cells. Cross-sectional scanning electron microscopy (SEM) imaging is employed to examine the degree of electrolyte infiltration into the nanostructured electrodes as a function of filling conditions. Using these techniques, conditions are identified for achieving a high degree of pore filling by the three electrolyte systems. Increased power conversion efficiency is obtained when iodine is introduced after the heating and evacuation procedures required for maximum infiltration.     

Concomitants of social support: Social skills, physical attractiveness, and gender.

Investigated the naturally occurring relations among self-reported social support and social skills, on the one hand, and behavioral measures and rated physical attractiveness on the other, using 84 male and 84 female undergraduates who were selected on the basis of high- and low-number scores on the Social Support Questionnaire. Ss were videotaped in 2 dyadic situations with a same-sex partner. Ss also completed the UCLA Loneliness Questionnaire, a social competence questionnaire, a story completion task, and self and partner evaluations. The videotaped behavior was rated qualitatively and quantitatively. Results show significant differences in the social skills of Ss who were high and low in social support; Ss high in social support were more favorably evaluated. Women also were found to be significantly more socially skilled and were rated as being more physically attractive than men. The various self-report and behavioral measures of social skills were significantly interrelated. Results indicate the dimensions of social support by demonstrating the relation between social support and social skills. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delayed Double Treatment with Adult-Sourced Adipose-Derived Mesenchymal Stem Cells Increases Striatal Medium-Spiny Neuronal Number,Decreases Striatal Microglial Number,and Has No Subventricular Proliferative Effect,after Acute Neonatal Hypoxia-Ischemia in Male Rats

Perinatal hypoxia-ischemia (HI) is a major cause of striatal injury. Delayed post-treatment with adult-sourced bone marrow-derived mesenchymal stem cells (BMSCs) increased the absolute number of striatal medium-spiny neurons (MSNs) following perinatal HI-induced brain injury. Yet extraction of BMSCs is more invasive and difficult compared to extraction of adipose-derived mesenchymal stem cells (AD-MSCs), which are easily sourced from subcutaneous tissue. Adult-sourced AD-MSCs are also superior to BMSCs in the treatment of adult ischemic stroke. Therefore, we investigated whether delayed post-treatment with adult-sourced AD-MSCs increased the absolute number of striatal MSNs following perinatal HI-induced brain injury. This included investigation of the location of injected AD-MSCs within the brain, which were widespread in the dorsolateral subventricular zone (dlSVZ) at 1 day after their injection. Cells extracted from adult rat tissue were verified to be stem cells by their adherence to tissue culture plastic and their expression of specific ‘cluster of differentiation’ (CD) markers. They were verified to be AD-MSCs by their ability to differentiate into adipocytes and osteocytes in vitro. Postnatal day (PN) 7/8, male Sprague-Dawley rats were exposed to either HI right-sided brain injury or no HI injury. The HI rats were either untreated (HI + Diluent), single stem cell-treated (HI + MSCs×1), or double stem cell-treated (HI + MSCs×2). Control rats that were matched-for-weight and litter had no HI injury and were treated with diluent (Uninjured + Diluent). Treatment with AD-MSCs or diluent occurred either 7 days, or 7 and 9 days, after HI. There was a significant increase in the absolute number of striatal dopamine and cyclic AMP-regulated phosphoprotein (DARPP-32)-positive MSNs in the double stem cell-treated (HI + MSCs×2) group and the normal control group compared to the HI + Diluent group at PN21. We therefore investigated two potential mechanisms for this effect of double-treatment with AD-MSCs. Specifically, did AD-MSCs: (i) increase the proliferation of cells within the dlSVZ, and (ii) decrease the microglial response in the dlSVZ and striatum? It was found that a primary repair mechanism triggered by double treatment with AD-MSCs involved significantly decreased striatal inflammation. The results may lead to the development of clinically effective and less invasive stem cell therapies for neonatal HI brain injury.     

Circuit and Coil Design for In-Vitro Magnetic Neural Stimulation Systems

Magnetic stimulation of neural tissue is an attractive technology because neural excitation may be affected without requiring implantation of electrodes. Pulsed discharge circuits are typically implemented for clinical magnetic stimulation systems. However, pulsed discharge systems can confound in-vitro experimentation. As an alternative to pulsed discharge circuits, we present a circuit to deliver asymmetric current pulses for generation of the magnetic field. We scaled the system down by using ferrite cores for the excitation coil. The scaled system allows observation using electrophysiological techniques and preparations not commonly used for investigation of magnetic stimulation. The design was refined using a comprehensive set of design equations. Circuit modeling and simulation demonstrate that the proposed system is effective for stimulating neural tissue with electric-field gradients generated by time-varying magnetic fields. System performance is verified through electrical test.     

Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence

Countless millions of people have died from tuberculosis, a chronic infectious disease caused by the tubercle bacillus. The complete genome sequence of the best-characterized strain of Mycobacterium tuberculosis, H37Rv, has been determined and analysed in order to improve our understanding of the biology of this slow-growing pathogen and to help the conception of new prophylactic and therapeutic interventions. The genome comprises 4,411,529 base pairs, contains around 4,000 genes, and has a very high guanine + cytosine content that is reflected in the biased amino-acid content of the proteins. M. tuberculosis differs radically from other bacteria in that a very large portion of its coding capacity is devoted to the production of enzymes involved in lipogenesis and lipolysis, and to two new families of glycine-rich proteins with a repetitive structure that may represent a source of antigenic variation.