Theoretical studies on VPI-5. 3. The MS-Q force field for aluminophosphate zeolites

Aluminophosphate zeolite is an artificial material which shows strange hydrophilicity. We have been investigating the reason by quantum mechanics, and found that the hydrophilicity of this zeolite depended on the local geometric deformation, and speculated that the site-specific hydrophilicity might be explained by differences in the stiffness of the local deformation determined by the location with the pore structure. In order to test these ideas, we construct a reliable force field based on the new MS-Q approach developed by Demiralp, Cagin, and Goddard. Our force field well reproduces the experimental structure of VPI-5.     

The HMG-CoA Reductase Gene and Lipid and Lipoprotein Levels: the Multi-Ethnic Study of Atherosclerosis

HMG-CoA reductase (HMGCR) is an enzyme involved in cholesterol synthesis. To investigate the contribution of the HMGCR gene to lipids and lipoprotein subfractions in different ethnicities, we performed an association study in the Multi-Ethnic Study of Atherosclerosis (MESA). In total, 2,444 MESA subjects [597 African-Americans (AA), 627 Chinese-Americans (CHA), 612 European-Americans (EA), and 608 Hispanic-Americans (HA)] without statin use were included. Participants had measurements of blood pressure, anthropometry, and fasting blood samples. Subjects were genotyped for 10 single nucleotide polymorphisms (SNPs). After excluding SNPs with minor allele frequency <5%, a single block was constructed. The most frequent haplotype was H1 (41–56%) in all ethnic groups except AA (H2a, 44.9%). Lower triglyceride level was associated with the H2a haplotype in AA and H2 in HA. In HA, H4 carriers had higher levels of triglyceride and small low-density lipoprotein (s-LDL), and lower high-density lipoprotein cholesterol (HDL-c), while carriers with H7 or H8 had associations with these traits in the opposite direction. No significant association was discovered in both CHA and EA. The total variation for triglyceride that could be explained by H2 alone was 2.6% in HA and 1.4% in AA. In conclusion, HMGCR gene variation is associated with multiple lipid/lipoprotein traits, especially with triglyceride, s-LDL, and HDL-c. The impact of the genetic variance is modest and differs greatly among ethnicities.     

Visualizing "green oil" in live algal cells

We report here that BODIPY 505/515, a green lipophilic fluorescent dye, serves as an excellent vital stain for the oil-containing lipid bodies of live algal cells. BODIPY 505/515 vital staining can be used in combination with fluorescent activated cell sorting to detect and isolate algal cells possessing high lipid content.     

Cognitive skill acquisition and transfer in younger and older adults.

The acquisition of cognitive skills often depends on 1 of (or a combination of) 2 processes, the execution of an algorithm, and the retrieval of problem instances. This study examined the effects of age and repetition of problem instances on the production and verification of solutions to 2 serially presented sets of alphabet arithmetic problems. Analyses of the parameters derived from power-function fits for individuals revealed age differences favoring young adults in improvement span, learning rate, and asymptote. For both age groups, the beneficial effects of repetitions on 1st-set response times were attributable to algorithmic speedup and to the retrieval of instances, whereas improvements in the speed of 2nd-set response times were attributable primarily to item retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suboptimality in human categorization and identification.

Categorization and identification decision processes were examined and compared in 4 separate experiments. In all tasks, the critical stimulus component was a line that varied across trials in length and orientation, and the optimal decision rules were always complex piecewise quadratic functions. Evidence was found that identification is mediated by separate explicit and implicit systems. In addition, a common type suboptimality was found in both categorization and identification. In particular, observers apparently approximated the piecewise quadratic functions of the optimal decision rules with simpler piecewise linear functions. A computational model, which was motivated by a recent neuropsychological theory of category learning, successfully accounted for this suboptimal performance in both categorization and identification. The model assigns a key role to the striatum and assumes the observed suboptimality was largely due to massive convergence of visual cortical cells onto single striatal units. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Young children in the aftermath of the World Trade Center attacks.

The attacks of September 11, 2001, on the World Trade Center were unprecedented acts of terrorism on U.S. soil. The disaster provides an opportunity to understand the responses of young children to a traumatic event of this proportion. This retrospective study took place within a year of the attacks and examined the relationship of levels of exposure to the World Trade Center disaster and family level predictors to trauma symptoms in a highly exposed sample of 180 young children in New York City. Data were collected through interviews with parents of children five years or younger at the time of the attacks. Primary variables included direct exposure and post 9/11 child and parent functioning, including trauma symptoms. Child trauma symptoms were related to direct exposure to the disaster, previous trauma, negative changes in parenting, and increased couple tension. Findings support the conceptualization that children's responses to traumatic events must be addressed within the caregiving context of family relationships. Clinical and preventive intervention for young children should be aimed at multiple levels of the social ecology. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Novel fire resistant matrixes for composites from cyclic poly(butylene terephthalate) oligomers

The objective of the work is to exploit the processing advantages of c-PBT oligomers, essentially required in industrial practice to produce new, robust, multifunctional hybrid copolymers of c-PBT oligomers in a single reaction-molding step, which will be suitable for the use in continuous fiber composites with excellent flame retardant properties. In this article a series of copolyesters were synthesized by using in situ polymerization of cyclic poly(butylene terepthalate) oligomers (c-PBT) and hydroxyl terminated bisphenols and hydroxylated siloxanes in the presence of a tin catalyst at a moderate temperature. The in situ copolymerization was conducted with various c-PBT/tetrabromobisphenol A (TBBPA), bisphenol A diglycidyl ether (BPADGE) and Carbinol PDMS feed ratios respectively. The copolyesters were characterized by GPC, NMR, and DSC techniques. Pyrolysis-combustion flow calorimeter (PCFC) and pyrolysis gas chromatography/mass spectrometry (PyGC/MS) studies were performed to characterize the fire retardant properties of the copolymers during combustion. POLYM. ENG. SCI., 47:1536–1543, 2007. © 2007 Society of Plastics Engineers     

Objective and subjective socioeconomic status and susceptibility to the common cold.

Objective: We ask whether subjective socioeconomic status (SES) predicts who develops a common cold when exposed to a cold virus. Design: 193 healthy men and women ages 21-55 years were assessed for subjective (perceived rank) and objective SES, cognitive, affective and social dispositions, and health practices. Subsequently, they were exposed by nasal drops to a rhinovirus or influenza virus and monitored in quarantine for objective signs of illness and self-reported symptoms. Main Outcome Measures: Infection, signs and symptoms of the common cold, and clinical illness (infection and significant objective signs of illness). Results: Increased subjective SES was associated with decreased risk for developing a cold for both viruses. This association was independent of objective SES and of cognitive, affective and social disposition that might provide alternative spurious (third factor) explanations for the association. Poorer sleep among those with lesser subjective SES may partly mediate the association between subjective SES and colds. Conclusions: Increased Subjective SES is associated with less susceptibility to upper respiratory infection, and this association is independent of objective SES, suggesting the importance of perceived relative rank to health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Guest Editors' Introduction: System IC Design Challenges beyond 32 nm

This special issue highlights ongoing research to address some of the challenges in the design of large ICs with dimensions well below 100 nm. The Gigascale Systems Research Center is organized around four themes and a design driver, and each is represented in this issue. There is also an exciting interview with Intel chair Craig Barrett. Accompanying the theme articles are three sidebars written by industry leaders (Richard Oehler of AMD, Ajith Amerasekera of Texas Instruments, and Leon Stok of IBM) on the challenges they see on the horizon, the paths being taken to address these challenges, and the role university programs can play. In addition, a Perspectives article by John Zolper discusses the value of this collaborative program to US national interests, including national security. Finally, there is a Last Byte column by the FCRP executive director Betsy Weitzman.