A superconducting magnetic spectrometer for cosmic ray nuclei

Equipment specifications for balloon carried superconducting magnetic spectrometer to measure spectra of cosmic ray nuclei with charges ranging from protons to iro

Computer simulation of protein systems

Ligand binding to dihydrofolate reductase (DHFR) is discussed. This is an extremely important enzyme, as it is the target of several drugs (inhibitors) which are used clinically as antibacterials, antiprotozoals and in cancer chemotherapy. DHFR catalyzes the NADPH (reduced nicotinamide adenine dinucleotide phosphate) dependent reduction of dihydrofolate to tetrahydrofolate, which is used in several pathways of purine and pyrimidine iosynthesis, including that of thymidylate. Since DNA synthesis is dependent on a continuing supply of thymidylate, a blockade of DHFR resulting in a depletion of thymidylate can lead to the cessation of growth of a rapidly proliferating cell line. DHFR exhibits a significant species to species variability in its sensitivity to various inhibitors. For example, trimethoprim, an inhibitor of DHFR, binds to bacterial DHFR's 5 orders of magnitude greater than to vertebrate DHFR's. The structural mechanics, dynamics and energetics of a family of dihydrofolate reductases are studied to rationalize the basis for the inhibitor of these enyzmes and to understand the molecular basis of the difference in the binding constants between the species. This involves investigating the conformational changes induced in the protein on binding the ligand, the internal strain imposed by the enzyme on the ligand, the restriction of fluctuations in atom positions due to binding and the consequent change in entropy

Nocturnal Dexamethasone versus Hydrocortisone for the Treatment of Children with Congenital Adrenal Hyperplasia

Classic congenital adrenal hyperplasia affects approximately 1 in 15,000 children. Current treatment strategies using multiple daily doses of hydrocortisone lead to suboptimal outcomes. We tested the hypothesis that nocturnal administration of dexamethasone will suppress the hypothalamic-pituitary-adrenal axis more effectively than standard hydrocortisone treatment by blocking the inherent diurnal secretion of ACTH. We performed a pilot study of five prepubertal patients comparing CAH control during two 24-hour hospitalizations, one on hydrocortisone and the other on dexamethasone. The patterns of adrenal suppression differed markedly between hydrocortisone and nocturnal dexamethasone, with significant suppression of the morning rise in ACTH, 17-hydroxyprogesterone, and androstenedione while on dexamethasone. On hydrocortisone therapy, there is a marked variation in ACTH and adrenal hormones depending on time of day and timing of hydrocortisone administration. Longer-term studies are needed to investigate the lowest effective dose and potential toxicity of nocturnal dexamethasone to determine its utility as a therapy for CAH

Linking Session Focus to Treatment Outcome in Evidence-Based Treatments for Adolescent Substance Abuse

The relation between specific therapy techniques and treatment outcome was examined for 2 empirically supported treatments for adolescent substance abuse: individual cognitive–behavioral therapy and multidimensional family therapy. Participants were 51 inner-city, substance-abusing adolescents receiving outpatient psychotherapy within a larger randomized trial. One session per case was evaluated using a 17-item observational measure of model-specific techniques and therapeutic foci. Exploratory factor analysis identified 2 subscales, Adolescent Focus and Family Focus, with strong interrater reliability and internal consistency. Process–outcome analyses revealed that family focus, but not adolescent focus, predicted posttreatment improvement in drug use, externalizing symptoms, and internalizing symptoms within both study conditions. Implications for the implementation and dissemination of individual-based and family-based approaches for adolescent drug use are discussed

Autonomy and Relatedness in Inner-City Families of Substance Abusing Adolescents

This study examined parent-adolescent autonomous-relatedness functioning in inner-city, ethnic minority families of adolescents exhibiting drug abuse and related problem behaviors. Seventy-four parent-adolescent dyads completed a structured interaction task prior to the start of treatment that was coded using an established autonomous-relatedness measure. Adolescent drug use, externalizing, and internalizing behaviors were assessed. Parents and adolescents completed assessment instruments measuring parenting style and family conflict. Confirmatory factor analysis found significant differences in the underlying dimensions of parent and adolescent autonomous-relatedness in this sample versus previous samples. It was also found that autonomous-relatedness was associated with worse adolescent symptomatology and family impairment. Results based on both self-report and observational measures contribute to the understanding of key family constructs in this population and provide insight for both researchers and the treatment community

A Comparison of Methods for Excluding Light from Stems to Evaluate Stem Photosynthesis

Premise A comparison of methods using different materials to exclude light from stems to prevent stem CO2 exchange (i.e., photosynthesis), without affecting stem conductance to water vapor, surface temperature, and relative humidity, was conducted on stems of avocado trees in California. Methods and Results The experiment featured three materials: aluminum foil, paper-based wrap, and mineral-based paint. We examined stem CO2 exchange with and without the light exclusion treatments. We also examined stem surface temperature, relative humidity, and photosynthetic active radiation (PAR) under the cover materials. All materials reduced PAR and stem CO2 exchange. However, aluminum foil reduced stem surface temperature and increased relative humidity. Conclusions Methods used to study stem CO2 exchange through light exclusion have historically relied on methods that may induce experimental artifacts. Among the methods tested here, mineral-based paint effectively reduced PAR without affecting stem surface temperature and relative humidity around the stem