Group identification as a moderator of the relationship between perceived social norms and alcohol consumption.

Previous research has shown that social norms are among the strongest predictors of college student drinking. Among college students, perceiving that others drink more heavily than themselves has been strongly and consistently associated with heavier drinking. Research has also shown that the more specifically others are defined, the stronger the association is with one's own drinking. In the current research, we evaluated whether group identification as defined by feeling closer to specific groups moderates the associations between perceived drinking norms in the group and one's own drinking. Participants included 3,752 (61% female) students who completed online assessments of their perceived drinking norms for 4 groups of students on their campus and identification with each group and participants' own drinking behavior. Results indicated that greater identification with same-sex students, same-race students, and same-Greek-status students was associated with stronger relationships between perceived drinking norms in the specific groups and own drinking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Highly Diverse Protein Library Based on the Ubiquitous (β/α)8 Enzyme Fold Yields Well‐Structured Proteins through in Vitro Folding Selection

Proper protein folding is a prerequisite for protein stability and enzymatic activity. Although directed evolution can be a powerful tool to investigate enzymatic function and to isolate novel activities, well‐designed libraries of folded proteins are essential. In vitro selection methods are particularly capable of searching for enzymatic activities in libraries of trillions of protein variants, yet high‐quality libraries of well‐folded enzymes with such high diversity are lacking. We describe the construction and detailed characterization of a folding‐enriched protein library based on the ubiquitous (β/α)₈ barrel fold, which is found in five of the six enzyme classes. We introduced seven randomized loops on the catalytic face of the monomeric, thermostable (β/α)₈ barrel of glycerophosphodiester phosphodiesterase (GDPD) from Thermotoga maritima. We employed in vitro folding selection based on protease digestion to enrich intermediate libraries containing three to four randomized loops for folded variants, and then combined them to assemble the final library (10¹⁴ DNA sequences). The resulting library was analyzed by using the in vitro protease assay and an in vivo GFP‐folding assay; it contains ～10¹² soluble monomeric protein variants. We isolated six library members and demonstrated that these proteins are soluble, monomeric and show (β/α)₈‐barrel fold‐like secondary and tertiary structure. The quality of the folding‐enriched library improved up to 50‐fold compared to a control library that was assembled without the folding selection. To the best of our knowledge, this work is the first example of combining the ultra‐high throughput mRNA display method with selection for folding. The resulting (β/α)₈ barrel libraries provide a valuable starting point to study the unique catalytic capabilities of the (β/α)₈ fold, and to isolate novel enzymes.     

A brief, web-based personalized feedback selective intervention for college student marijuana use: A randomized clinical trial.

Despite clear need, brief web-based interventions for marijuana-using college students have not been evaluated in the literature. The current study was designed to evaluate a brief, web-based personalized feedback intervention for at-risk marijuana users transitioning to college. All entering first-year students were invited to complete a brief questionnaire. Participants meeting criteria completed a baseline assessment (N = 341) and were randomly assigned to web-based personalized feedback or assessment-only control conditions. Participants completed 3-month (95.0%) and 6-month (94.4%) follow-up assessments. Results indicated that although there was no overall intervention effect, moderator analyses found promising effects for those with a family history of drug problems and, to a smaller extent, students who were higher in contemplation of changing marijuana use at baseline. Implications of these findings for selective intervention of college marijuana use and web-based interventions in general are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

As we may think-revisited [the future of the Internet]

With the approach of the 21st Century, computer and software technologies have changed the very fabric of our society. Beyond the sheer advances in processor speed, the most dramatic, far-reaching changes have occurred in the way we transfer information. Through the medium of the Internet, information can now be transmitted instantaneously from one end of the planet to the other. The future of information technology is bright, to be sure, but not without its challenges. For the Internet to enable us to achieve all our goals, it must gain a real-time context of who we are, our state and what we are doing. To this end, we must decouple context from the GUI and move it into a system built to hold it: a context engine. This system will let each of us organize our information according to the way we think, by association     

Screening for alcoholism among persons with recent traumatic brain injury.

This study examined the clinical utility of various brief screening procedures for identifying persons with a prior history of alcoholism among patients with recent traumatic brain injury (TBI). Participants were 50 patients assessed for various aspects of alcohol use and abuse during their acute rehabilitation hospitalization. Predictive indicators were tested against the Michigan Alcoholism Screening Test (MAST) as the criterion measure. Results indicated the 13-item Short Michigan Alcoholism Screening test is a good proxy for the longer MAST in this population. The two screening questions by M. Cyr and S. Wartman (1988) also have some limited utility. Practical implications of the results are discussed with a view toward adopting universal screening for alcoholism among persons with recent TBI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality

Background

Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria.

Methods

Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined.

Results

Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies did not provide evidence for an adverse role of phosphate, milk, and grain foods in osteoporosis.

Conclusions

A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health.     

Addition of sodium bicarbonate to rations of pre- and postpartum dairy cows

Sodium bicarbonate was added to complete mixed rations to evaluate the effect of buffer addition on adaptation to high-energy rations by dairy cows in elderly lactation. Forty-five Holstein cows were assigned to one of three treatment groups: control pre- and postpartum; control prepartum, buffer postpartum; and buffer pre- and postpartum. Rations consisted of 85% chopped grass hay: 15% concentrate prepartum and 60% corn silage:40% concentrate postpartum. On day 4 postpartum, cows were switched abruptly to the postpartum ration for 9 wk. Buffered rations contained .6% sodium bicarbonate prepartum and .7% postpartum. Daily dry matter intake as a percent of body weight for cows fed buffer postpartum (3.51%) was greater than for cows fed no buffer (3.04%) of buffer pre- and postpartum (3.14%). Average production of 4% fat-corrected milk was greater for cows fed buffer postpartum and buffer pre- and postpartum (31.9 kg/day and 31.7 kg/day) than for cows fed no buffer (28.9 kg/day). Milk fat tests were not different. Cows fed the buffered rations lost body weight between wk 1 and 9 as compared to a net gain for cows fed no buffer. Cows fed buffers consumed more dry matter during wk 1 than did cows fed no buffer. Samples of rumen fluid, feces, and serum showed few differences that could be attributed to treatments. Compared to controls, cows fed sodium bicarbonate adapted to rations more rapidly postpartum as indicated by increased feed intake during the first 2 wk and by increased milk production during the first 4 wk of the trial.     

Isoflurane Potentiation of GABAA Receptors Is Reduced but Not Eliminated by the β3(N265M) Mutation

Background: Mice carrying the GABA_A receptor β3(N265M) point mutation, which renders receptors incorporating β3-subunits insensitive to many general anesthetics, have been used experimentally to link modulation of different receptor subtypes to distinct behavioral endpoints. Remarkably, however, the effect of the mutation on the susceptibility to modulation by isoflurane (a standard reference agent for inhalational vapors) has never been tested directly. Therefore, we compared the modulation by isoflurane of expressed α5β3(N265M)γ2L receptors with their wild type counterparts. Methods: Using whole-cell electrophysiological recording and rapid solution exchange techniques, we tested the effects of isoflurane at concentrations ranging from 80 μM to 320 μM on currents activated by 1 μM GABA. We measured drug modulation of wild-type α5β3γ2L GABA_A receptors and their counterparts harboring the β3(N265M) mutation. Results: Currents elicited by GABA were enhanced two- to four-fold by isoflurane, in a concentration-dependent manner. Under the same conditions, receptors incorporating the β3(N265M) mutation were enhanced by approximately 1.5- to two-fold; i.e., modulation by isoflurane was attenuated by approximately one-half. Direct activation by isoflurane was also present in mutant receptors but also attenuated. Conclusions: In contrast to the complete insensitivity of β3(N265M) mutant receptors to etomidate and propofol, the mutation has only a partial effect on receptor modulation by isoflurane. Therefore, the persistence of isoflurane effects in mutant mice does not exclude a possible contribution of β3-GABA_A receptors.     

Use of drinking protective behavioral strategies in association to sex-related alcohol negative consequences: The mediating role of alcohol consumption.

Alcohol use has been implicated as a risk factor for sexual negative consequences, such as unprotected sexual intercourse. The present research was conducted to examine the relationship between drinking protective behavioral strategies and consensual sex-related alcohol negative consequences, and whether this relationship varied by gender. Additionally, typical number of drinks during sexual behavior was evaluated as a potential mediator of this association. Heavy drinking, sexually active college students (N = 297, 50.2% women) completed self-report measures of drinking protective behavioral strategies, alcohol consumption, and sex-related alcohol negative consequences. Findings indicated that women who used drinking protective behavioral strategies more frequently were less likely to experience sex-related alcohol negative consequences whereas this relationship was not significant for men. For women, this relationship was mediated by the typical number of drinks consumed during sexual behavior. The current research demonstrates that use of drinking protective behavioral strategies is related to a reduction in women's sex-related risks when drinking. Findings are discussed in terms of alcohol myopia theory. Implications for interventions aimed to reduce higher risk sexual behavior among college students are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)