Evaluating gene × psychological risk factor effects in the pathogenesis of anxiety: A new model approach.

The present study evaluated the singular and interactive effects of a functional polymorphism (variation) in the serotonin transporter (5-HTT) gene and a psychological trait (anxiety sensitivity [AS], i.e., fear of arousal symptoms) in predicting subjective and physiological responses to a 35% carbon dioxide (CO?) challenge in a community sample (N?=?72). Genotypes were divided into 2 groups in accord with prior research. Findings were partially supportive of the hypothesized risk model. These indicated that the Group L genotype (homozygous for the 1 allele), compared with the Group S genotype (homozygous for the s allele plus heterozygous individuals), predicted greater fearful response to the biological challenge. There was also an AS?×?Genotype interaction predicting heart rate variability (HRV) in response to the CO?, suggesting that high AS plus Group L status predicts decreased HRV. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conformations of macromolecular sequential polypeptides in solution: 2. Sequential polypeptides containing both d- and l-residues

The conformations adopted in solution by two series of macromolecular sequential polypeptides containing up to four γ-benzyl-d-glutamyl and one γ-benzyl-l-glutamyl or l-leucyl residue in the repeating unit have been studied by spectroscopic methods (i.r., o.r.d., n.m.r.). The nature of the ordered conformations encountered is discussed; it is suggested that they are a distorted form of the α-helix and special types of cross β-structure.     

Sulfonated polyisobutylene telechelic ionomers

The gelation of polyisobutylene-based model ionomers with-S0₃ ^–K⁺ terminal groups has been studied in hexane at 25°C. Both molecular architecture and molecular weight were found to significantly influence the concentration at which gelation occurs. Specifically, three-arm star trifunctional ionomers gel at lower concentrations than linear difunctional ionomers of similar molecular weight. In addition, the gelation concentration decreases with increasing molecular weight for the three-arm star trifunctional ionomer, but the results do not fit the relationship reported previously which relates gelation concentration and molecular weight for carboxylated linear telechelic polymers.     

Computer application of the tracking-function approach to practical stability

A computing algorithm based on the tracking-function method is presented for obtaining regions of practical stability and ultimate boundedness for second-order autonomous differential equations. It is shown that the algorithm obviates certain problems of the tracking-function method as originally formulated. The Van der Pol equation is analysed as an example.     

Heat transfer in a gas fluidized bed assisted by an alternating electric field

The application of an alternating electric field to cause movement of particles charged naturally by contact electrification in a fluidized bed, has be     

Midpoint potentials of the mitochondrial cytochromes of Crithidia fasciculata

The midpoint potentials of the mitochondrial respiratory chain cytochromes of the protozoan Crithidia fasciculata at pH 7.2, Em7.2, show great similarity to those measured in higher organisms. Values of Em7.2 for cytochromes a and a3 are +165 and +340 mV. Both c cytochromes have Em7.2 = +230 mV. There are two b cytochromes with the same spectral characteristics with Em7.2 = -20 and -135 mV. These values are compatible with two sites of energy conservation for oxidative phosphorylation in these mitochondria. All cytochrome components show potentiometric titrations with n = 1. There is a fluorescent flavoprotein in these mitochondria with Em7.2 = -40 mV and n =2, whose function is not known.     

Performance of everyday actions in mild Alzheimer's disease.

Early neuropsychological deficits associated with mild Alzheimer's disease (AD) have been characterized as memory deficits and impaired executive function or attention. The functional impact of early impairment was investigated by evaluating performance of everyday actions in older adults with mild AD (n = 15) as compared with healthy age-matched controls (n = 16). Everyday actions were familiar activities, for example, making a cup of tea, but were varied in complexity (simple, complex) and were performed under varied attention demand (single task, dual task). Although both participant groups responded to increasing task complexity by making more errors, the AD group made more errors under dual-task conditions regardless of the complexity of the task. Furthermore, a task requiring strategic retrieval of semantic information from long-term memory and manipulation of attention online (category fluency) was able to account for a large proportion of the group-related variance in everyday task performance. Results are discussed in relation to the role of components of working memory in performance of everyday actions in mild AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of hypoxia on the activity and binding of glycolytic and associated enzymes in sea scorpion tissues

The effect of hypoxia on the levels of glycogen, glucose and lactate as well as the activities and binding of glycolytic and associated enzymes to subcellular structures was studied in brain, liver and white muscle of the teleost fish, Scorpaena porcus. Hypoxia exposure decreased glucose levels in liver from 2.53 to 1.70 mumol/g wet weight and in muscle led to its increase from 3.64 to 25.1 mumol/g wet weight. Maximal activities of several enzymes in brain were increased by hypoxia: hexokinase by 23%, phosphoglucoisomerase by 47% and phosphofructokinase (PFK) by 56%. However, activities of other enzymes in brain as well as enzymes in liver and white muscle were largely unchanged or decreased during experimental hypoxia. Glycolytic enzymes in all three tissues were partitioned between soluble and particulate-bound forms. In several cases, the percentage of bound enzymes was reduced during hypoxia; bound aldolase in brain was reduced from 36.4 to 30.3% whereas glucose-6-phosphate dehydrogenase fell from 55.7 to 28.7% bound. In muscle PFK was reduced from 57.4 to 41.7% bound. Oppositely, the proportion of bound aldolase and triosephosphate isomerase increased in hypoxic muscle. Phosphoglucomutase did not appear to occur in a bound form in liver and bound phosphoglucomutase disappeared in muscle during hypoxia exposure. Anoxia exposure also led to the disappearance of bound fructose-1,6-bisphosphatase in liver, whereas a bound fraction of this enzyme appeared in white muscle of anoxic animals. The possible function of reversible binding of glycolytic enzymes to subcellular structures as a regulatory mechanism of carbohydrate metabolism is discussed.