Spectrophotometric estimation of arsenic in nitric acid extracts of soil and soil additives

The spectrophotometric determination of arsenic in solutions containing nitric acid necessitates the removal of nitrate ions without loss of arsenic. A convenient and effective method for its removal was achieved by treatment with formic acid.     

Representativeness of clinical samples of youths with mental disorders: A preliminary population-based study.

In a household community sample of 1,285, 9–17 year-olds with mental disorders who had received outpatient specialty mental health services in the past year were compared with youths with mental disorders who had not received those services to determine if samples drawn from clinical settings are representative of youths with mental disorders in the general population. Those who had used services were more impaired, less competent, more likely to have comorbid disorders, more likely to belong to non-Hispanic White relative to other ethnic groups, and less likely to be prepubertal girls. Their parents were more educated, but less satisfied with family life, engaged in less monitoring of their children, and more likely to have used mental health services themselves. These findings suggest the hypothesis that samples of youths with mental disorders drawn from outpatient clinical settings are not representative of all youths with mental disorders. If confirmed, this would indicate the importance of population-based samples for the study of psychopathology in youths. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Glucocapparin variability among four populations ofIsomeris arborea Nutt

Glucocapparin (methylglucosinolate), a putative defense compound, was found to vary between desert and nondesert populations ofIsomeris arborea (Capparaceae): Plants from desert populations contained greater concentrations than nondesert plants in four of the five organs analyzed. Immature leaves at desert sites had average glucocapparin concentrations of 9.2 mg/g and 8.4 mg/g, while nondesert sites averaged 6.0 mg/g and 4.6 mg/g. Mature leaves from desert sites had average concentrations of 12.8 mg/g and 7.9 mg/g; leaves from plants at nondesert sites contained approximately one third to one half of those concentrations. A similar pattern was observed in capsule walls and seeds but not in flower buds; for these, non-desert plants contained a slightly higher concentration of glucocapparin. Our studies show that nitrogen and glucocapparin concentrations fluctuate throughout the year and contribute to the observed variability among populations during any particular season. Glucocapparin may fluctuate seasonally as much as 37% in immature leaves and 78% in mature leaves. In a controlled experiment, glucocapparin concentration varied inversely with nitrogen fertilizer treatment. The plants treated with fertilizer lacking nitrogen ranged from 10.1 mg/g to 10.9 mg/g glucapparin, which was roughly twice the concentration of those supplied with 20 mM nitrogen in the fertilizer.     

Diffusion in a unidirectional filament reinforced metal composite

A theoretical analysis has been developed to describe composition changes resulting from exposure of a unidirectional filament reinforced metal composite to an elevated temperature environment. The analysis was based on a simple superposition of finite-difference solutions of the diffusion equation, and was applicable to the case for which the filament and matrix metals comprised an isomorphous binary alloy system. The possibility of chemical reaction between filaments and matrix was excluded. Excellent agreement was obtained between calculated concentration profiles and results of quantitative electron microprobe analyses of nickel filament reinforced copper samples. However, the agreement was found to be quite sensitive to the dependence of diffusivity on concentration.     

The formation of Cu3Sn intermetallic on the reaction of cu with 95Pb-5Sn solder

This study characterizes the interfacial reactions that occur when Cu is soldered with 95 Pb-5Sn solder. A continuous layer of Cu₃Sn ε phase forms during the soldering process. Previous studies suggest that the intermetallic layer spalls off during soldering. However, the present work shows that the intermetallic layer is intact after soldering and that any spalling observed is due to improper polishing. A new polishing technique was developed to preserve the intermetallic layer. The Cu³Sn has a fine columnar grain structure that is very brittle. Both intergranular and transgranular fracture modes are observed. The size of the intermetallic layer is dependent upon the length of time the solder is molten. The rate of formation of e phase was measured and used to determine an activation energy for diffusion of Sn in 95Pb-5Sn of 13 kcal/mol.     

Digital simulation of an impulse turbine: the Bradley Lake Project

A digital simulation and stability study of the Bradley Lake (Alaska) hydroelectric project is discussed. The basic system consists of two 45-MW, multiple-jet impulse turbines supplied by a three-mile conduit. A digital governor is utilized. Once produced, the simulation is used to investigate the stability of the system. The system was found to be locally stable, but unstable to large perturbations. Due to economic constraints in plant design, the response of the system to load acceptance is poor     

Influence of Uric Acid on Photostability of Fd& C Blue no. 2

The effect of uric acid as a photoprotective agent for various solutions of FD&C Blue No. 2 was investivated. Due to the poor aqueous solubility of uric acid, solutions were made in glycerin, triethanolamine and N/5 NaOH. Uric acid in glycerin or triethanolamine was found to enhance the photostability of the dye solutions. The higher the concentration of uric acid in triethanolamine, the greater was the photoprotective action of uric acid. Increasing the amount of glycerin in solution resulted in acceleration of the rate of fading of the color presumably due to dielectric constant effect. The photoprotective action of uric acid was found to be influenced by the pH of the medium and its buffer species.     

Periodic discharges observed in a cerebral vascular accident (author's transl)

The authors report a case of cerebral softening in which almost entirely unilateral periodic discharges were observed. They consisted of isolated high-voltage spiked waves predominating distinctly on the side of the lesion. The interval between spikes was always 2-3 seconds. The origin of these signs is discussed. The fact that they are not necessarily related to an infectious or metabolic disease is underlined.