Anode region design and focusing properties of STAR silicon drift detectors

Electron collection at the anodes of large-area silicon drift detectors was studied with STAR2 prototypes. Results of measurements of anode leakage currents, signal dependence on focusing voltages, anode uniformity, and model simulations are reported. A design of the anode region is presented. The design optimization is discussed.     

Altered state of hypnosis: Changes in the theoretical landscape.

Presentations of theories of hypnosis in scholarly and introductory texts portray the field as dominated by two warring camps, variously referred to as state and nonstate or as special process and social psychological. Current issues and theories in the hypnosis literature are examined. In the process, we seek to dispel the myth that hypnosis theorists can be grouped into two camps. Although there is considerable controversy about the nature of hypnosis, no issues separate all so-called special process theorists from all social psychological theorists. Instead, virtually all substantive differences between theorists cut across this apparent distinction. Furthermore, the positions taken on many of the important issues dividing the field can no longer be portrayed as simple dichotomies, such as state vs nonstate or trait vs situation. Positions on these issues can more accurately be described as points on a continuum. We conclude by drawing attention to specific questions and issues that remain unresolved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tantalum oxide coatings as candidate environmental barriers

Tantalum (Ta) oxide, due to its high-temperature capabilities and thermal expansion coefficient similar to silicon nitride, is a promising candidate for environmental barriers for silicon (Si) nitride-based ceramics. This paper focuses on the development of plasma-sprayed Ta oxide as an environmental barrier coating for silicon nitride. Using a D-optimal design of experiments, plasma-spray processing variables were optimized to maximize coating density. The effect of processing variables on coating thickness was also determined. X-ray diffraction (XRD) was use to ascertain that the as-sprayed coatings were comprised of α- and β-Ta₂O₅, but were fully converted to β-Ta₂O₅ after a 1200 °C heat treatment. Grain growth of the Ta₂O₅ followed a time dependence of t ^0.2 at 1200 °C.     

Uptake and metabolism of lipoprotein-X in mesangial cells

An HPLC method developed to detect in a single run both atenolol and chlorthalidone, extracted from plasma, using two detectors (UV for chlorthalidone and fluorometric for atenolol) connected in series, is described. The drugs were separated on an ODS column at room temperature using a 0.05 M sodium dodecyl sulphate in phosphate buffer (pH 5.8)-n-propanol (95:5, v/v) solution, delivered at a flow-rate of 1.3 ml/min. Having ascertained the sensitivity (10 ng/ml of both drugs) and the intra-day reproducibility (pre-study validation), the reliability of the method was verified by inter-day assays (within-study validation) carried out during the analysis of plasma samples collected from healthy volunteers after single-dose treatment with atenolol+chlorthalidone tablets (pharmaceutical preparations containing 100+25 mg and 50+12.5 mg of the two drugs, respectively).     

Age-related deficits in context discrimination learning in Ts65Dn mice that model Down syndrome and Alzheimer's disease.

All individuals with Down syndrome (DS) eventually develop the neuropathology of Alzheimer's disease (AD), which is characterized by a premature loss of basal forebrain cholinergic neurons. Similarly, between 4 and 6 months of age, Ts65Dn mice, which model DS, lose cholinergic markers in their medial septal neurons. It is not known whether Ts65Dn mice have age-related learning deficits as well. Control and Ts65Dn mice were tested at several ages in context discrimination. Controls at all ages showed no deficits in learning this task. Ts65Dn mice younger than 3 months demonstrated impaired learning, suggesting a possible developmental delay in Ts65Dn mice. Four-month-old Ts65Dn mice showed no deficits, whereas Ts65Dn mice older than 5 months were impaired in learning the task. Therefore, Ts65Dn mice have an age-related learning impairment that coincides with their age-related neuroanatomical abnormalities and, consequently, may be a useful model of AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increasing teacher praise and altering its distribution to children of differing on-task levels.

Following baseline observations, 37 Grade 5 children were divided into high, medium, and low on-task groups. Treatment phases included general audio-cuing for teacher praise; cuing combined with instructions, feedback, and praise to focus 67% of the teacher praise on the low on-task subgroup; cuing with focusing instructions removed; and cuing with daily feedback. The increase in teacher praise resulting from general audio-cuing was relatively evenly distributed among the 3 subgroups but increased to 67.3% of the total in favor of the low on-task group with the focusing package. Removal of the focusing procedure decreased the praise rate for this group to 19.4%. Changes in on-task student behavior varied as a function of base rate and treatment condition. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biochemical,Structural, and Genetic Characterization of Tridecaptin A1, an Antagonist of Campylobacter jejuni

Bacillus circulans NRRL B‐30644 (now Paenibacillus terrae) was previously reported to produce SRCAM 1580, a bacteriocin active against the food pathogen Campylobacter jejuni. We have been unable to isolate SRCAM 1580, and did not find any genetic determinants in the genome of this strain. We now report the reassignment of this activity to the lipopeptide tridecaptin A₁. Structural characterization of tridecaptin A₁ was achieved through NMR, MS/MS and GC‐MS studies. The structure was confirmed through the first chemical synthesis of tridecaptin A₁, which also revealed the stereochemistry of the lipid chain. The impact of this stereochemistry on antimicrobial activity was examined. The biosynthetic machinery responsible for tridecaptin production was identified through bioinformatic analyses. P. terrae NRRL B‐30644 also produces paenicidin B, a novel lantibiotic active against Gram‐positive bacteria. MS/MS analyses indicate that this lantibiotic is structurally similar to paenicidin A.