Acquisition of iron by Gardnerella vaginalis

Six Gardnerella vaginalis strains were examined for the ability to utilize various iron-containing compounds as iron sources. In a plate bioassay, all six strains acquired iron from ferrous chloride, ferric chloride, ferrous sulfate, ferric ammonium citrate, ferrous ammonium sulfate, bovine and equine hemin, bovine catalase, and equine, bovine, rabbit, and human hemoglobin. All six strains also acquired iron from human lactoferrin, but not from human transferrin, as determined by a liquid broth growth assay. Siderophore production was detected in eight G. vaginalis strains by the chrome azurol S universal chemical assay. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the cytoplasmic membrane proteins isolated from G. vaginalis 594 grown under iron-replete and iron-restricted conditions revealed several iron-regulated proteins ranging in molecular mass from 33 to 94 kDa. These results indicate that G. vaginalis may acquire iron from iron salts and host iron compounds.     

Development and validation of the Need for Relatedness at College Questionnaire (NRC-Q).

Research indicates that reasons for attending college influence college success and that college students of color (CSC) can be motivated to attend college for different reasons than White college students (WCS). The Need for Relatedness at College Questionnaire (NRC-Q) was developed and tested to provide an instrument for identifying and understanding the various ways in which needs for relatedness, a salient motivator for many CSC, affect college success. On the basis of the recommendation from D. Guiffrida's (2006) cultural critique of V. Tinto's (1993) theory, the scale was developed with a self-determination theory (E. L. Deci & M. R. Ryan, 1991) perspective. Results support the content validity, internal consistency, temporal stability, and construct validity of the scale items, and a confirmatory factor analysis supported the underlying structures of the scale. Results also suggest that college students' needs for relatedness at home are more complex than previous research has suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heterogeneous Approach to Modeling Contractors' Decision-to-Bid Strategies

This research is based on the premise that there is heterogeneity in the population of contractors, i.e., that individual contractors exhibit different bidding behavior when confronted with a given set of bidding variables. Random-coefficients logistic model is used to explicitly measure the heterogeneity across contractors in terms of their (1) intrinsic bid/no-bid preferences and (2) responses to four bidding variables, i.e., number of bidders, market conditions, project type, and size. The binary bid/no-bid decisions were assumed to arise from a logistic model, but with the model parameters that varied between contractors. Data were gathered using a bidding experiment involving Hong Kong and Singapore contractors. The results show that there is significant heterogeneity across the contractors in which Hong Kong contractors can be clustered into four groups of identical (statistical) behavior in response to the four bidding variables, whereas in Singapore, there are only three groups as determined by the underlying heterogeneity distribution. This probabilistic classification of contractors has implications for contractors’ competitive strategies by targeting different groups of competitors toward maximum competitiveness.     

The use of solid electrolytes in the determination of activities and the development of sensors

Solid electrolytes have been known for decades, but it is only recently that the drive to develop new methods of electricity generation and storage has led to the development of new solid electrolytes. This article discusses the use of solid electrolytes in the measurement of activities of solutes, dissolved in molten metals, and the development of sensors that may find industrial application for on-line measurements in the metallurgical industry. This article is based on a presentation given in the Mills Symposium entitled “Metals, Slags, Glasses: High Temperature Properties & Phenomena,” which took place at The Institute of Materials in London, England, on August 22–23, 2002.     

When are morphemic and semantic priming observed in visual word recognition?

J. Stolz and D. Besner (1998) reported a dissociation between morphemic and semantic priming in the context of lexical decision. Morphemic priming was observed following letter search on the prime display, but semantic priming was not. The 14 participants in the present experiment identified the color of a single letter in the prime display before making a lexical decision to the target. Both morphemic and semantic priming were observed. These results are discussed in relation to the observation that identifying the color of a single letter of a word in the Stroop task is associated with a reduction in the size of the Stroop effect as compared to when all letters are colored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the practice of dichotomization of quantitative variables.

The authors examine the practice of dichotomization of quantitative measures, wherein relationships among variables are examined after 1 or more variables have been converted to dichotomous variables by splitting the sample at some point on the scale(s) of measurement. A common form of dichotomization is the median split, where the independent variable is split at the median to form high and low groups, which are then compared with respect to their means on the dependent variable. The consequences of dichotomization for measurement and statistical analyses are illustrated and discussed. The use of dichotomization in practice is described, and justifications that are offered for such usage are examined. The authors present the case that dichotomization is rarely defensible and often will yield misleading results. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Selective preference in visual fixation away from negative images in old age? An eye-tracking study.

Recent studies have suggested that older individuals selectively forget negative information. However, findings on a positivity effect in the attention of older adults have been more mixed. In the current study, eye tracking was used to record visual fixation in nearly real-time to investigate whether older individuals show a positivity effect in their visual attention to emotional information. Young and old individuals (N = 64) viewed pairs of synthetic faces that included the same face in a nonemotional expression and in 1 of 4 emotional expressions (happiness, sadness, anger, or fear). Gaze patterns were recorded as individuals viewed the face pairs. Older adults showed an attentional preference toward happy faces and away from angry ones; the only preference shown by young adults was toward afraid faces. The age groups were not different in overall cognitive functioning, suggesting that these attentional differences are specific and motivated rather than due to general cognitive change with age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive-behavioral interventions with older adults: Integrating clinical and gerontological research.

Psychotherapeutic interventions utilizing cognitive-behavioral strategies have been used widely with older adults. To appropriately adapt these techniques, characteristics unique to older adults must be taken into account. These factors include aspects of the social environment, cohort effects, cognitive changes with aging, personality, and emotional development, which have been described in an emerging body of research literature from the field of gerontology. In addition, clinical studies have examined the efficacy of cognitive-behavioral interventions in treating older clients for anxiety, depression, insomnia, and other disorders. This review describes current empirical evidence in gerontology and treatment outcome research that informs the practice of psychotherapy in this population and provides recommendations for conducting therapy with older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Carbamazepine and lamotrigine in healthy volunteers: relevance to early tolerance and clinical trial dosage

This study was conducted to examine the effects of acute doses of lamotrigine (LTG) and carbamazepine (CBZ) in healthy subjects and determine whether the low tendency to impairment with LTG observed in animals applied to humans. Twelve healthy men participated in a placebo-controlled, balanced, double-blind comparison of the drugs on a series of psychomotor, autonomic, sensory, and subjective variables. Variables were analyzed by analysis of variance, and p < 0.05 was considered significant. Adaptive tracking and body sway were impaired by CBZ 600 mg. CBZ 400 and 600 mg impaired smooth pursuit eye movements and also reduced mean peak saccadic velocity. No differences from placebo occurred after LTG. CBZ 600 mg increased heart rate (HR), but no drug-related changes were noted in pupil size, salivary secretion, visual near point, or subjective effects. During the controlled study, mean plasma CBZ concentrations at 2 and 6.5 h after the 600-mg dose were 5.28 and 5.36 micrograms/ml; after LTG 300 mg, they were 3.16 and 3.00 micrograms/ml. Increased CBZ saliva concentrations were significantly associated (p < 0.01) with impaired adaptive tracking, smooth and saccadic eye movements and increased HR, and plasma concentrations were associated with impaired eye movements and body sway.     

The parabrachial nucleus: A brain stem substrate critical for mediating the aversive motivational effects of morphine.

Bilateral ibotenic acid lesions of the lateral, but not the medial, parabrachial nucleus (PBN) blocked conditioned taste aversion (CTA) induced by morphine but not conditioned place preference induced by morphine. The same lateral PBN lesions also blocked conditioned place aversion produced by low intraperitoneal doses of morphine (shown to produce aversion, instead of preference, due to a restricted action on gut opiate receptors). Lateral PBN lesions did not block CTA produced by LiCl. Cerebral peduncle lesions that destroyed the direct descending projections from the visceral cortex to the PBN did not block CTA induced by morphine, nor did ibotenic acid lesions of the tegmental pedunculopontine nuclei (shown to block place preference produced by even high morphine doses). It is suggested that the lateral PBN is a critical link in the neural pathway carrying the aversive motivational effects of opiates from the gut into the CNS, independent of the neural pathway carrying the rewarding motivational effects of morphine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)