The effect of Na addition on the first hydrogen absorption kinetics of cast hypoeutectic Mg–La alloys

With superior properties of Mg such as high hydrogen storage capacity (7.6 wt% H/MgH₂), low price, and low density, Mg has been widely studied as a promising candidate for solid-state hydrogen storage systems. However, a harsh activation procedure, slow hydrogenation/dehydrogenation process, and a high temperature for dehydrogenation prevent the use of Mg-based metal hydrides for practical applications. For these reasons, Mg-based alloys for hydrogen storage systems are generally alloyed with other elements to improve hydrogen sorption properties. In this article, we have added Na to cast Mg–La alloys and achieved a significant improvement in hydrogen absorption kinetics during the first activation cycle. The role of Na in Mg–La has been discussed based on the findings from microstructural observations, crystallography, and first principles calculations based on density functional theory. From our results in this study, we have found that the Na doped surface of Mg–La alloy systems have a lower adsorption energy for H₂ compared to Na-free surfaces which facilitates adsorption and dissociation of hydrogen molecules leading to improvement of absorption kinetic. The effect of Na on the microstructure of these alloys, such as eutectic refinement and a density of twins is not highly correlated with absorption kinetics.     

Simple material parameter estimation via terahertz time-domain spectroscopy

A simple and precise method based on fixed-point iteration is used to estimate dielectric parameters using terahertz time-domain spectroscopy (THz-TDS). The method converges and gives correct parameters when the sample thickness is greater than 200 /spl mu/m at a frequency of 0.1 THz or 20 /spl mu/m at a frequency of 1.0 THz. The technique in validated using measured terahertz data, obtained by probing a sample of high-resistivity silicon.     

The effect of ambient temperature on the sensitivity of hot-cathode ionization gauges

We measured the sensitivities of five hot-cathode ionization gauges for ambient laboratory temperatures between 23 and 31 °C. All of the ionization gauges exhibited very similar behavior, and the sensitivity could be adequately modeled with a linear function of temperature. The slopes of the fits were smaller than one would expect due to changes in the calibration chamber number density. The thermal transpiration effect, due to local heating of the gauge structures, can account for this, and a characteristic gauge tube temperature can be inferred from the temperature dependence of the sensitivity. A recent comparison of the high vacuum standards of several National Metrology Institutes (NMIs) was performed over the range of 10⁻⁶-10⁻³ Pa using hot-cathode and spinning rotor gauges as transfer standards. Among the participants, laboratory temperatures varied by as much as 5 °C. It is necessary to know how laboratory temperature affects the sensitivity of the hot-cathode transfer standards (spinning rotor gauges explicitly account for the gas temperature) so that individual laboratory results can be corrected to a common temperature.     

GnRH molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes). Immunological and chromatographic evidence for the presence of a novel molecular variant

Gonadotropin-releasing hormone (GnRH) molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes), were characterized by gradient reverse phase high performance liquid chromatography (RP-HPLC). Eluted fractions were tested in radioimmunoassays with different antisera. The results show that the brain extract contains three forms of GnRH: one is immunologically and chromatographically similar to cIIGnRH (chicken II), and another is similar to sGnRH (salmon). A third GnRH appears to be chromatographic and immunologically different from the nine other known forms of the vertebrate hormone. This is the only variant present in the pituitary gland.     

Early intervention for spelling problems: Teaching functional spelling units of varying size with a multiple-connections framework.

Poor spellers in 2nd grade (n?=?128) participated in 24 20-min sessions that included (a) direct instruction in the alphabet principle (most frequent phoneme-spelling connections); (b) modeling of different approaches, singly and in combination, for developing connections between spoken and written words for 48 words ordered by sound-spelling predictability; and (c) practice in composing. Results of this multilayered intervention showed that (a) more than 1 way of developing sound-spelling connections is effective in teaching spelling but that after training in the alphabet principle, combining whole word and onset-rime training is most effective in achieving transfer of the alphabet principle across word contexts; (b) functional spelling units of not only a single letter but also 2 or more letters are important in beginning spelling; and (c) training in spelling transfers to composition and word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Post-Event Rumination and Negative Self-Appraisal in Social Phobia Before and After Treatment.

This study investigated the relationship between self-appraisals of performance, symptom severity and post-event rumination in social phobia, and evaluated the effect of treatment on these variables. A socially phobic group and a nonanxious control group performed an impromptu speech and were told that their performance would be evaluated. Participants appraised their performance immediately after the speech and 1 week later, and the frequency of post-event rumination during the week following the speech was assessed. The socially phobic group maintained the negative appraisals of their speech over the week, whereas the nonclinical group showed increased positivity about their performance The socially phobic group also engaged in more negative rumination than controls. Treatment improved perceptions of performance and reduced negative rumination. These results are discussed in the light of cognitive models of social phobia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A strategy for improving patient satisfaction by the intensive training of residents in psychosocial medicine: a controlled, randomized study

PURPOSE: To use a controlled, randomized design to assess the effect on patient satisfaction of an intensive psychosocial training program for residents. METHOD: Twenty-six first-year residents, in two internal medicine and family practice community-based programs affiliated with the Michigan State University College of Human Medicine, were randomly assigned during 1991 and 1992 to a control group or a one-month intensive training program. Experiential teaching focused on many psychosocial skills required in primary care. A 29-item questionnaire administered before and after the residents' training evaluated their patients' satisfaction regarding patient disclosure, physician empathy, confidence in physician, general satisfaction, and comparison of the physician with other physicians. Analyses of covariance with groups and gender as factors and pre-training patient satisfaction scores as the covariate evaluated the effect of the training. RESULTS: The patients of the trained residents expressed more confidence in their physicians (p = .01) and more general satisfaction (p = .02) than did the patients of controls. The effect of training on patient satisfaction with patient disclosure (p < .01) and physician empathy (p < .05) was greater for female than for male residents. CONCLUSION: The intensive psychosocial training program for residents improved their patients' satisfaction.