Tarasoff: 10 years later.

This article reviews the Tarasoff case and other cases decided since the California Supreme Court issued its decision. The changing interpretation of the decision, the broadening of its applicability, and legislative reactions are also discussed. Recommendations for psychotherapists who may have to make decisions about potentially violent clients are noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disruption of vitamin D receptor-retinoid X receptor heterodimer formation following ras transformation of human keratinocytes

A partial resistance to the growth inhibitory influence of 1, 25-dihydroxyvitamin D3 is apparent when immortalized keratinocytes are transformed by the ras oncogene. The vitamin D receptor (VDR) was isolated, analyzed, and found to be identical in normal, immortalized, and ras-transformed keratinocytes. Subsequently, nuclear extracts from immortalized and ras-transformed keratinocytes were analyzed in gel mobility shift assays utilizing labeled vitamin D response elements or thyroid hormone response elements. A specific protein.DNA complex that was shown to contain VDR using an anti-VDR antibody was identified in both types of extracts; however, the addition of an anti-retinoid X receptor (RXR) antibody identified RXR in the complex of both normal and immortalized keratinocyte cell extracts, but not in ras-transformed keratinocytes. Furthermore, transfection of ras-transformed keratinocytes with wild-type human RXRalpha rescued VDR.RXR and thyroid hormone receptor.RXR complexes as demonstrated by a supershift in the presence of the anti-RXR antibody. Both cell lines were found to express RXRalpha message in equal amounts. Western blot analysis revealed that RXRalpha protein from ras-transformed keratinocytes was indistinguishable from that from immortalized keratinocytes and from control cells. These results suggest a causal relationship between resistance to the growth inhibitory influences of 1,25-dihydroxyvitamin D3 and disruption of the VDR.RXR complex in malignant keratinocytes.     

Optimization studies of CVD growth of GaAs0.6P0.4

CVD growth conditions, particularly growth temperature and partial pressures of the reactant gases, strongly affect the growth characteristics and properties of GaAs_0.6P_0.4 epitaxial layers grown on GaAs substrates. For LED’s the most important properties of the material are B/J (brightness per unit current density) and surface morphology. This paper presents the results of a systematic study of the effect of temperature and reactant gas partial pressure (at a fixed III/V ratio) on B/J, surface morphology, growth rate, impurity doping and layer composition. Growth conditions which yield the optimum properties for LED’s are determined. The results are interpreted on the basis of kinetic and thermodynamic mechanisms controlling the growth process under various growth conditions. At constant temperature and constant III/V ratio, increasing the partial pressures causes the growth process to change from mass transport limited, where the growth rate increases with increasing partial pressures, to kinetically limited, where the growth rate is independent of partial pressures. Good morphology layers are obtained over a range of partial pressures around the transition from mass transport limited to kinetically limited growth. The B/J peaks at a value of partial pressure in the kinetically limited regime at which good morphology layers are obtained. Although B/J increases with increasing growth rate in the mass transport regime, the maximum B/J occurs in the region where growth rate is independent of partial pressures so that growth rate alone is not sufficient to determine B/J. In contrast to the “parabolic≓ dependence of growth rate on growth temperature, caused by the transition from the mass transport regime to the kinetic regime, the relative incorporation of As, P, and Te varies with temperature in the manner predicted from thermodynamics in both regimes. This behavior is consistent with the growth rate in the kinetic regime being limited by the desorption of chlorine atoms from the growth surface, with the reaction of As, P, and Te with the Ga proceeding thermodynamically at all temperatures.     

Evolution of fuel nitrogen in coal devolatilization

The distribution of fuel nitrogen in the devolatilization products of a lignite and 12 bituminous coals has been observed experimentally. For these coals under isothermal conditions (300 < T < 1000 °Cand 5 < t < 80 s) the behaviour of the nitrogen evolution was found to be similar. Nitrogen which is initially released is contained almost entirely in the tar. The chemical composition, ¹³C-n.m.r. spectra and infrared spectra of the tars and parent coals are strikingly similar and it is reasonable to suspect that the tar nitrogen occurs in the same structures as in the parent coal. Secondary release of nitrogen into nontar volatiles occurs only at high temperature. Results can be described with first-order kinetics using the same rate constant for all the coals studied. Initial nitrogen release is described by the tar release rate constant, k = 81 exp (−5800/T) (s⁻¹), which is similar to the rate constant for initial nitrogen release measured by Pohl and Sarofim. Secondary release of nitrogen is described with a rate constant which is similar to the results measured by Blair, Wendt and Bartok. This rate is smaller than that measured for the decomposition of nitrogen-ring compounds such as pyridines or pyrroles. The results suggest that coal nitrogen is contained almost entirely in tightly bound rings which are released without breakage in the tar during the initial stage of devolatilization; the remainder is released at higher temperatures when rings are ruptured.     

The importance of dietary control in metabolic studies of manic-depressive patients

Diet control of electrolyte intake appears to diminish day to day variation of urinary electrolyte output. Urine sodium concentration is more affected by diet control than potassium, possibly due to the greater variation in sodium ingestion on uncontrolled diets. The coefficient of variation of urinary sodium excretion on the controlled diet was not significantly greater than the variation in sodium ingestion. These experimental results suggest that controlled diets reduce random variation in sodium and potassium excretion and therefore enhance the possibility of observing illness-related biological changes.     

Operant responding for visual stimuli during sensory deprivation: Effect of meaningfulness.

Employed slide series differing in amount of meaningfulness as reinforcers for conjugately programed operant responding during 2-hr sessions of sensory deprivation and control conditions. Ss were 36 student nurses, 17-22 yr. old. Every S had the opportunity to respond to the slide series under both sets of conditions. Rates of responding under both conditions were higher for the more meaningful slide series, but rates of responding for the least meaningful reinforcers were higher under sensory deprivation conditions than under control conditions. Results are interpreted as indicating a need for nonmeaningful stimulation and for meaningful stimulation during sensory deprivation. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Radical bulk polymerization of N-vinylcaprolactam

Bulk radical polymerization of N-vinylcaprolactam was studied at temperatures between 60 and 120°C. with different initiators. Satisfactory results were obtained with azobisisobutyronitrile, tert-butyl perbenzoate, and tert-butyl peroxide as initiators. The polymerization reaction of N-vinylcaprolactam with these initiators is first order with respect to the monomer and 0.5 order with respect to the initiator. A linearity of the kinetic curves up to high conversions was observed. The cause of this behavior is a feeble gel effect, which also induces an increase of the molecular weight during polymerization.