Crystal growth and characterization of Pt0.97S2

Large, well-formed plates of Pt_0.97 S₂ were grown by chemical vapor transport. A combination of phosphorus and chlorine was used as the transport agent. The best crystals were grown when the charge zone was maintained at 800°C and the growth zone at 740°C. The crystals were found to be diamagnetic with a susceptibility of ?31(2) × 10^?6 emu/mole at 77°K and showed semiconducting behavior with a band gap of 0.20(2)eV. From Hall voltage measurements, the sign of the carriers was ascertained to be positive. Pt_0.97S₂ particles less than 63μ underwent thermal decomposition in air at 270(10)°C.     

Genetically obese (ob/ob) mice are predisposed to gastric stress ulcers.

In Exp I, 20 adult male genetically obese (ob/ob) mice and 20 lean littermate controls were food deprived and subsequently physically restrained at normal room temperatures. Obese Ss became hypothermic and developed gastric stress ulcers. Lean Ss maintained normal body temperatures and did not form gastric ulcers. In Exp II, 5 male obese and 4 lean littermates were used to test the effects of noradrenaline (NA) during restraint, and 5 obese and 5 lean mice were used to test the effects of NA alone. It was expected that in lean, but not in obese, Ss that NA would induce an increase in O? consumption beyond that induced by initial restraint. O? consumption was measured during food deprivation and restraint. Obese and lean Ss had parallel metabolic responses, with obese Ss using significantly less O? at all times. The predisposition to formation of gastric ulcers is a new phenotypic expression of the ob/ob genotype. The pathogenesis of this susceptibility appears to be related to a genetic disturbance in heat production. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A randomized study of two doses of abdominopelvic radiation therapy for patients with optimally debulked Stage I, II, and III ovarian cancer

BACKGROUND & AIMS: An elevated transferrin saturation is the earliest phenotypic abnormality in hereditary hemochromatosis. Determination of transferrin saturation remains the most useful noninvasive screening test for affected individuals, but there is debate as to the appropriate screening level. The aims of this study were to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals and to evaluate potential transferrin saturation screening levels. METHODS: Statistical mixture modeling was applied to data from a survey of asymptomatic Australians to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals. To evaluate potential transferrin saturation screening levels, modeling results were compared with data from identified hemochromatosis heterozygotes and homozygotes. RESULTS: After removal of hemochromatosis homozygotes, two populations of transferrin saturation were identified in asymptomatic Australians (P < 0.01). In men, 88.2% of the truncated sample had a lower mean transferrin saturation of 24.1%, whereas 11.8% had an increased mean transferrin saturation of 37.3%. Similar results were found in women. A transferrin saturation threshold of 45% identified 98% of homozygotes without misidentifying any normal individuals. CONCLUSIONS: The results confirm that hemochromatosis heterozygotes form a distinct transferrin saturation subpopulation and support the use of transferrin saturation as an inexpensive screening test for hemochromatosis. In practice, a fasting transferrin saturation of > or = 45% identifies virtually all affected homozygous subjects without necessitating further investigation of unaffected normal individuals.     

Performance characteristics of a 1.5 μm single-frequencysemiconductor laser with an external waveguide Braff reflector

Single-frequency operation of 1.5-μm semiconductor lasers was obtained by combining a regular Fabry-Perot laser to an external waveguide Bragg reflector. The laser is characterized by very pure single-frequency operation, 10-MHz linewidth, and greatly-reduced frequency chirp under direct modulation. The laser has been tested in 1.7-Gb/s transmission experiments over 82.5 km of fiber     

The full coverage restoration in relation to the gingival sulcus

The full coverage restoration (FCR) and its effect on the periodontium have been the subject of much controversy over the last half century. The conflict relates to whether the margin of the FCR should be placed at or above the gingival crest, or into the gingival crevice. Clinicians and researchers alike have focused their attention primarily on the mechanistic aspects of fixed prosthetic design (i.e., marginal configuration and fit). Although marginal quality and form are factors in the fabrication of the FCR, they alone will not determine periodontal health and restorative success. What determines the success of the FCR is its ability to restore form and function to the masticatory system without adversely affecting its biology. Each technical phase of treatment (i.e., tooth preparation, impression-taking, the provisional restoration, and the final restoration) must be performed within the limits of biologic adaptation. This literature review discusses the scientific evidence regarding FCR margin placement and periodontal health.     

Self-report knowledge: At the crossroads of ability, interest, and personality.

The authors describe an approach to adult intellect on the basis of content, unlike the traditional approach, which is mostly based on process. Thirty-two academic knowledge scales were rated by 202 college students, who also completed ability, vocational interest, and personality scales. Analyses of knowledge clusters and individual scales were used to evaluate commonality across ability constructs (verbal and spatial ability), vocational interests (realistic, investigative, and artistic), and personality (typical intellectual engagement and openness). The results support knowledge differentiation across fluid and crystallized abilities, show a pattern of positive correlations of arts and humanities knowledge with typical intellectual engagement and openness, and show correlations between math and physical sciences knowledge and realistic and investigative interests. Implications for the study of adult intelligence are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taking reading comprehension exams on screen or on paper? A metacognitive analysis of learning texts under time pressure

People often attribute their reluctance to study texts on screen to technology-related factors rooted in hardware or software. However, previous studies have pointed to screen inferiority in the metacognitive regulation of learning. The study examined the effects of time pressure on learning texts on screen relative to paper among undergraduates who report only moderate paper preference. In Experiment 1, test scores on screen were lower than on paper under time pressure, with no difference under free regulation. In Experiment 2 the time condition was manipulated within participants to include time pressure, free regulation, and an interrupted condition where study was unexpectedly stopped after the time allotted under time pressure. No media effects were found under the interrupted study condition, although technology-related barriers should have taken their effect also in this condition. Paper learners who preferred this learning medium improved their scores when the time constraints were known in advance. No such adaptation was found on screen regardless of the medium preference. Beyond that, paper learning was more efficient and self-assessments of knowledge were better calibrated under most conditions. The results reinforce the inferiority of self-regulation of learning on screen and argue against technology-related factors as the main reason for this.