Isolation of Densification Regions During Powder Compression

An instrumented single punch tablet press has been used to monitor the deformation behavior of materials. Lubricated excipients were compressed to the same maximum punch penetration in a constant fill volume and the densification process was followed. The densification of the powder to form a tablet and the corresponding pressures generated in the die were monitored by the instrumentation. The sampling rate per channel was one data point every 0.5 millisecond in a 1.02 second event. Plots of the densification, In (1 / porosity) versus upper punch pressure in the die, were generated for each tablet formation. The densification plots have six regions which can be isolated based on the upper punch movement in the die. A material's deformation behavior can be described by the densification and pressure changes occurring in the various regions.     

MLEK crystal growth of (100) indium phosphide

We have used a combined magnetic liquid encapsulated Kyropoulos/Czochralski (MLEK/ MLEC) technique to produce twin-free indium phosphide (InP) crystals. This technique has advantages over the standard LEC method used for commercial production of InP. By stabilizing convective flows with a magnetic field and controlling the angle between solid and liquid, one can grow large diameter twin-free (100) InP crystals; they are shaped with a flat top as is typical for Kyropoulos growth, and then pulled from the magnetically stabilized melt as in Czochralski growth. This shaping method has the benefit of maximizing the number of single crystal wafers which can be sliced from the boule. MLEK InP growth is distinguished from other methods such as LEC and MLEC with respect to solid-liquid interface shape, dislocation density, and impurity distribution. This process has demonstrated that twin-free InP (100) crystals can be consistently grown.     

Formation of Mullite from Sol-Gel Mixtures and Kaolinite

Critical analyses of published reaction studies on kaolinite, and sol-gel and powder mixtures equivalent to 3Al₂O₃·2SiO₂ mullite, were made. Supplementary experiments on reactions of kaolinite at different rates of heating were analyzed. Complete atomic homogeneity of precursors results in formation of tetragonal mullite. Colloidal precursors initially form spinel which reacts with the remaining silica by a diffusion-nucleation mechanism to form orthorhombic mullite. Precursors with intermediate atomic homogeneity follow both reaction paths. Kaolinite with a layer lattice structure has two-dimensional atomic homogeneity. Both reaction routes are followed and their degree of interaction is dependent on the crystallinity and impurities of the kaolinite.     

Internal reliability and convergent validity of the Depression-Happiness Scale with the General Health Questionnaire in an employed adult sample

Salmonella Typhimurium was isolated from a fresh fecal sample of zebra finches (Poephila guttata) in December 1992 on an aviary where a large scale outbreak of S. Typhimurium infection among bengalees (a variety of Lonchura striata) in 1991 had been recorded. The isolates from zebra finches were examined for antibiotic sensitivity and plasmids, which were 60 Mdal, then they showed the same pattern as those of S. Typhimurium isolated at the previous outbreak. This is the first report of S. Typhimurium isolation from zebra finches.     

Emotional arousal and overeating in restrained eaters.

Tested the effects of 3 mood inductions (neutral, positive, and negative) on food intake in 91 women of varying degrees of dietary restraint. Mood induction was accomplished by exposure to 1 of 3 film segments: a travelogue (neutral affect), a comedy film (positive affect), and a horror film (negative affect). In Ss exposed to the neutral film, food intake decreased with increasing levels of dietary restraint. Among Ss who viewed either the comedy film or the horror film, however, food intake increased with increasing restraint. Although the horror film appeared to be more disinhibiting than the comedy film, this effect may have resulted from a difference in the intensity of the emotions induced rather than from their valence. These results suggest that emotional arousal, regardless of valence, may trigger overeating among restrained eaters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of prenatal PCB exposure on cognitive processing efficiency and sustained attention.

Assesses 4-yr-old children exposed prenatally to polychlorinated biphenyls (PCBs; an environmental toxin) on 3 tasks: 2 designed to evaluate cognitive processing efficiency and 1 to evaluate sustained attention. When compared with standardized IQ tests, these tasks provided greater specificity in identifying cognitive deficits. Adapted for 4-yr-old children in the present study, these paradigms demonstrated moderate levels of test–retest reliability. Prenatal exposure to PCBs was associated with less efficient visual discrimination processing and more errors in short-term memory scanning but not with sustained attention. Although much larger quantities of these contaminants are transferred postnatally via breastfeeding than prenatally across the placenta, postnatal exposure was unrelated to cognitive performance. The data link intrauterine PCB exposure to 2 dimensions of cognitive functioning fundamental to learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

COMPUTATIONAL STUDY OF N@C60, P@C60, AND As@C60

Semiempirical and density functional theory structural calculations on Group V atom-endohedral complexes are reported. While reports, in some instances contradictory, on the structure of N@C₆₀ have appeared in the literature, this is the first computational study that includes both phosphorous and arsenic as endohedral atoms. Potential energy functions for all complexes are also reported. The calculations indicate that, as the atoms are translated towards the cages, weak covalent bonds external to the cage are possible. There is a significant difference between the potential surface for the nitrogen complex and that of either phosphorous or arsenic. The nitrogen surface is repulsive for movement of the endohedral atom off-center. The curves for the other atoms are essentially flat with displacement. The potential curves have also been calculated for the reaction products of the complexes with azides. Similar potentials, as a function of endohedral atom displacement, were observed. The relative experimental stabilities of the complexes are understood on the basis of these data.     

Dehydration anorexia in decerebrate rats.

Hypertonic saline (HS) administered intraperitoneal/ly (ip) reduced the intake of sucrose solution infused intraorally in tube-fed decerebrate rats, as it did in control animals. Similarly, either ip or intravenous HS markedly decreased the intake of laboratory chow by neurologically intact control rats. These observations complement recent findings that lesions of putative osmoreceptors in the ventral diencephalon, which eliminate thirst and blunt pituitary secretion of vasopressin and oxytocin in response to HS in rats, have no apparent effect on the HS-induced inhibition of food intake. Taken together they support previous studies indicating an important role for the caudal brainstem in the central control of food intake and suggest that such brainstem control may also include the inhibition of food intake induced by acute hyperosmolality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of ethanol on low density lipoprotein and platelet composition

The present study was designed to investigate the effect of ethanol (EtOH) dose on low density lipoprotein (LDL) and platelet composition. Male squirrel monkeys were divided into three groups designated Control, Low, and High EtOH, and fed isocaloric liquid diets containing 0%, 12%, and 24% of calories as EtOH, respectively. After four months of treatment, monkeys fed the 12% alcohol dose had LDL and platelet cholesterol concentrations similar to Controls. By contrast, platelet membranes from High EtOH animals contained significantly more cholesterol which was associated with higher levels of plasma LDL cholesterol and apolipoprotein B. Blood platelet count, size, and mass were similar for all groups and circulating platelet aggregates were absent in the two alcohol cohorts. Despite elevations in platelet cholesterol mass and thromboxane A₂ (TXA₂) precursor, phospholipid arachidonate, platelet responsiveness, measured as thromboxane formed in response to a collagen challengein vitro, and the cholesterol/phospholipid molar ration, were not significantly altered by high dose alcohol. Normal platelet activity in High EtOH monkeys may have resulted from a significant increase in the platelet phospholipid polyunsaturated/saturated fatty acid ratio and a non-significant increase in platelet phospholipid mass, both of which would have a fluidizing effect on platelet membranes. Our data indicate that low EtOH intake has no effect on platelet composition and function while unfavorable platelet cholesterol enrichment following consumption of high dose ethanol may arise from elevations in plasma LDL. Potentially thrombogenic (TXA₂ formation, platelet aggregate formation) consequences of increased platelet cholesterol in squirrel monkeys fed high levels of alcohol may be averted by compensatory physicochemical changes in platelet membrane lipid composition although persistent elevations in circulating LDL may contribute to increased risk of cardiovascular disease.