Palm readings

Scientists are taking technology in common laboratory usage for more than 15 years and adapting it in ways that may, quite literally, bring the laboratory into the field. The technology is known as surface plasmon resonance (SPR), and a team of scientists has taken a sensing unit that was once the size of an old-fashioned console television and shrunken it down into a handheld unit no bigger than a conductor's baton.     

Titanium disulphide as a cathode material in lithium batteries — a review

The preparation, structure, intercalation reactions, and electrochemical properties of TiS₂ are reviewed. In particular we discuss the suitability of TiS₂ as a cathode material in secondary organic electrolyte—lithium batteries. Titanium disulphide is attractive for this application because of its ability to form intercalation compounds with alkali metals such as lithium. We conclude that it adequately fulfils most of the recognized criteria for a cathode material. The success of the LiTiS₂ system for high rate applications depends on the behaviour of TiS₂ at high current densities and under deep discharge conditions. Other factors such as the conductivity of the electrolyte and the recharge ability of the lithium electrode also need to be considered.     

In vivo chronoamperometric measurements of the clearance of exogenously applied serotonin in the rat dentate gyrus

The present study evaluated high-speed chronoamperometry as a method for measuring the clearance of serotonin (5-HT) from extracellular space in vivo. Male Sprague-Dawley rats were anaesthetized and a Nafion-coated, carbon fiber electrode, attached to a multibarrel pipette, was lowered into the subgranular layer of the dentate gyrus, a region which receives dense serotonergic innervation, or the corpus callosum, a fiber tract relatively devoid of the 5-HT transporter (SERT). Serotonin, pressure ejected into these regions, produced replicable electrochemical signals. The amplitude and time course of the signals were significantly prolonged in the corpus callosum compared to the dentate gyrus. Similarly, signals produced by locally applied 5-HT in the dentate gyrus of rats following destruction of hippocampal serotonergic innervation with 5,7-dihydroxytryptamine (5,7-DHT), were significantly enhanced compared to those observed in control animals. The time course of the 5-HT signal was significantly prolonged by local application of the selective 5-HT reuptake inhibitor, fluvoxamine, into the dentate gyrus. By contrast, fluvoxamine did not modify the clearance of 5-HT when locally applied into the dentate gyrus of 5,7-DHT lesioned rats or into the corpus callosum of intact rats. Taken together, these data demonstrate that in intact rats, the SERT contributes to the clearance of exogenously applied 5-HT from the extracellular space. Under the experimental conditions used in this study, high-speed chronoamperometry proved to be a reliable method for directly measuring extracellular 5-HT and appears to be a valuable tool for the study of 5-HT clearance by the SERT in vivo.     

Prediction of the lithium ratio in man by means of an in vitro test

The movement of the lithium ion (Li+) across the membrane of intact erythrocytes incubated in vitro was assessed under two different experimental conditions in which such transfer occurred primarily due to the activity of a lithium-sodium countertransport system. The 13 subjects on whom the in vitro procedures were done subsequently received lithium carbonate for 14 to 56 days, and the extent of accumulation of Li+ by erythrocytes in vivo was measured. While both in vitro procedures yielded data that correlated with the extent of accumulation of Li+ by erythrocytes in vivo, a system measuring the efflux of Li+ from Li+-loaded cells produced a much higher correlation (0.976). The magnitude of this correlation suggests that this in vitro system can be used for further investigations into the relevance of the erythrocyte accumulation of Li+ to the pathogenesis and treatment of affective disorders.     

The coulombic efficiency of zinc electrowinning in high-purity synthetic electrolytes

Measurements of coulombic efficiency (QE) for zinc electrodeposition were carried out under mass transfer-controlled conditions using a rotating disc electrode in synthetic acidic zinc sulphate electrolytes. At 25°C in 0.8 M ZnSO₄+1.07 M H₂SO₄ prepared from reagent grade chemicals, the QE at an aluminium cathode was 95.7–97.6%. In order to study the influence of electrolyte purity on QE several preparation and purification techniques were employed. While different sources of chemicals produced different QEs, the main source of impurities seemed to be the zinc-containing reagent rather than the sulphuric acid. Improvements in purity either had a negligible effect or lowered the QE, indicating that some impurities are beneficial to electrolyte performance. In the purest solutions prepared, an effect due to residual impurities still seemed to be present. The maximum QE obtainable through variation of the three parameters, i.e. temperature, current density and electrode rotation rate, was determined for two electrolytes of different purities; the values of QE obtained were 98.4 and 98.8%, with temperature as the dominant factor. Wark's Rule (the dependence of QE on zinc/acid ratio) was obeyed approximately in the purest electrolyte prepared, over a limited range of composition.     

Bias in prediction: A test of three models with elementary school children.

Studied 2 competing conceptualizations of test bias in educational settings and compared each to the traditional regression model. The bias model proposed by T. A. Cleary and that proposed by R. L. Thorndike (see record 1971-31520-001) were each employed, along with the traditional regression model, on data obtained from 95 male and 101 5th graders to determine the extent of sex bias in selection resulting from each of the 3 models. Results show that the Cleary procedure produced substantial bias in both selection and accuracy of selection in favor of the female subgroup. The traditional prediction model resulted in pronounced selection bias in favor of the male subgroup and a slight bias in accuracy of selection in favor of the same subgroup. The Thorndike procedure, by definition, results in no selection bias but did produce slight bias in the accuracy of selection favoring the female subgroup. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)