Impact grinding of thermoplastics: A size distribution function model

Separation of poly(ethylene terephthalate) (PET) from poly(vinyl chloride) (PVC) is an important problem when recycling bottles and other consumer products. Previous work has identified a processing window for the selective grinding of a mixture of PET and PVC. Impact grinding for conditions within the processing window will ensure that one polymer fails in the ductile mode and the other fails in the brittle mode, giving differences in sizes and shapes between the ground polymers. The ground mixture can be separated by physical means such as screening. This study develops size distribution models for the impact grinding of PET and PVC chips, an important tool for the operation and control of a selective grinding process. The distribution coefficients can be related to grinding conditions, and to the failure mechanism of the polymer.     

Self-reported parental abuse relates to autobiographical memory style in patients with eating disorders.

Previous research has shown a relationship between levels of self-reported childhood abuse and overgeneral memory style. This relationship was further clarified in patients with an eating disorder (ED). Patients and healthy controls completed a task in which they had to generate specific autobiographical memories to emotional cue words. The results showed that first, the ED group, relative to the controls, produced more first memories that were "overgeneral" and fewer first memories that were specific. Second, in the ED group, the level of self-reported parental abuse was positively correlated with the tendency to produce overgeneral memories to negative cues. This effect remained significant even after levels of depressed mood were controlled for. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

News: President's Risk Commission revises draft report, release set for January

Government.     

Thoracic tumors in children with neurofibromatosis-1

Lymphocytes were isolated from volunteers before and after receiving a single supplement of vitamin C, vitamin E or beta-carotene. The lymphocytes were treated with H2O2, and DNA strand breaks were measured by single cell gel electrophoresis (the comet assay). Significant protection against oxidative DNA damage was evident 2-4 h after vitamin C intake, and 18-24 h after consumption of the other antioxidants. Lymphocytes from smokers were more sensitive to DNA damage than those from non-smokers, and they showed at least as great a protective effect with antioxidants.     

The origin of hillocks in (Hg, Cd)Te grown by MOVPE

Dimethylcadmium, a precursor for the metalorganic vapor phase epitaxy of mercury cadmium telluride, has been shown to react with gallium arsenide to form trimethylarsine and dimethylarsine. An analogous reaction occurs between di-iso-propyltelluride and gallium arsenide to form iso-propylarsine and di-iso-propylarsine. It is proposed that if these reactions remove sufficient arsenic from a gallium arsenide substrate, metallic droplets will form on the wafer surface thereby creating the nucleation sites for hillocks. Analogous reactions have been observed between the precursors and a range of other substrates which can in turn be used to explain the origin of hillocks in epitaxial layers grown onto these materials.     

Multiple communicators with unique target information transmit less stereotypical impressions.

Four studies examined how multiple communicators who have unique target information transmit less stereotypical impressions. Co-communicators with unique information should feel accountable for providing unique perspectives and consequently will try to be accurate. This accuracy goal should increase their focus on stereotype-incongruent behaviors, resulting in more counterstereotypical transmissions. Study 1 showed that communicators with unique information about an alcoholic target abstractly characterized incongruent attributes and allocated more transmission time to them. Study 2 showed that the effect of communicators' unique information on receivers' less stereotypical impressions was mediated by focus on incongruent attributes. Because the first 2 studies used a target whose stereotypical features were negative, Studies 3 and 4 provided a replication with a target whose stereotypical features were positive. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dispositional and situational determinants of repression.

This research project posits a model of repression that incorporates both repressive personality and repressive social behavior. The 1st parameter of the model specifies the motivation for repressors' distancing of themselves from emotional events. Experiment 1 demonstrates that repressors are hypersensitive—in their cognitive attention—to both negative and positive emotional events. The 2nd parameter of the model specifies the conditions under which repressors distance themselves from emotional events. Experiments 2 and 3 demonstrate that repressors psychologically distance themselves when the situation threatens their self-evaluation and provides opportunity for them to attend to and process self-relevant and non-self-relevant information. This 2-factor model extends the current conceptualization of repression in that it identifies motivation ( dispositional emotional sensitivity ) and context ( situational threats to self-evaluation and distraction availability ) for repressors' distancing of themselves from negative and positive emotional events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decreased glutathione transferase activity in brain and ventricular fluid in Alzheimer's disease

OBJECTIVE: To investigate the levels of glutathione transferase (GST), a protective enzyme against aldehydes, and especially 4-hydroxynonenal (HNE) in the brain and ventricular CSF of autopsied AD and normal control subjects. BACKGROUND: Studies have implicated increased levels of oxidative stress in the brain in the pathogenesis of AD. Decreased levels of polyunsaturated fatty acids and increased levels of markers of lipid peroxidation have been reported in the brain in AD, particularly in areas severely affected in the disease. HNE, one marker of lipid peroxidation, is neurotoxic in neuronal culture and in vivo and is elevated in AD brain and CSF. METHODS: We measured levels of GST activity and protein in multiple brain regions and ventricular CSF in short-postmortem-interval AD patients and age-matched prospectively evaluated control subjects. RESULTS: A decrease in GST activity in all brain areas was observed in AD compared with controls with significant decreases in the amygdala, hippocampus and parahippocampal gyrus, inferior parietal lobule, and nucleus basalis of Meynert. Levels of GST protein also were depleted in most brain regions in AD. A significant decrease in GST activity and protein levels was also found in ventricular CSF in AD. CONCLUSION: Reduced levels of GST, a protective mechanism against HNE, may have a role in the pathogenesis of neuron degeneration in AD.