Effects of oral caffeine pretreatment on response to intravenous nicotine and cocaine.

Previous research suggests that under conditions of chronic daily caffeine administration, caffeine increases the effects of nicotine. Little is known about the effects of caffeine pretreatment on response to nicotine under infrequent caffeine administration conditions. The present study examined whether infrequent (not on consecutive days) acute oral caffeine administration alters subject-rated, physiological, and monetary value effects of intravenous nicotine in regular users of caffeine, tobacco, and cocaine. To determine the specificity of effects of caffeine on response to nicotine, the effects of caffeine administration on response to intravenous cocaine (another short-acting stimulant) were also studied. Fourteen (1 woman) volunteers participated in this 3–4 week, double-blind, inpatient study. Volunteers participated in 10 experimental conditions in pseudo-randomized order, in which oral caffeine (250 mg/70 kg) or placebo was administered 1 hr before an intravenous injection, consisting of nicotine (1 or 2 mg/70 kg), cocaine (15 or 30 mg/70 kg), or saline. Infrequent acute caffeine pretreatment attenuated the increase resulting from 2 mg/70 kg nicotine administration on ratings of “rush,” “good effects,” “liking,” “high,” and “drowsy/sleepy.” Caffeine had no significant effect on physiological response to nicotine. Caffeine had no significant effect on subject-rated and physiological response to cocaine, with the exception that caffeine significantly augmented blood pressure response to cocaine. In contrast to the previous research using chronic caffeine maintenance, these data suggest that infrequent acute caffeine administration may attenuate nicotine effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

School psychology practice: Organizational barriers to professional attainment.

Examined the organizational constraints to practitioner functioning that confront school psychologists. The results of a survey of 130 school psychologists show that Ss (a) spent more time testing than consulting; (b) spent their time performing many activities, such as consultation and counseling, for small amounts of time; and (c) wanted to do more consulting work, in-service training, and research. However, Ss reported significant support from other school staff members to perform duties other than testing. Ways of building on such support to enable the school psychologist to engage in these new roles are discussed. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual and group cognitive-behavioral treatment for work-related stress complaints and sickness absence: A randomized controlled trial.

Work-related stress is widespread and can lead to long-term absenteeism and work disability. Cognitive-behavioral treatment (CBT) has demonstrated effectiveness in treating psychopathology but has only rarely been tested in clinical samples with work-related stress. A randomized controlled trial was conducted to investigate the efficacy of CBT-based stress management training (SMT). Eighty-two patients on sickness leave with work-related stress were randomly assigned to (a) individual SMT, (b) group SMT, or (c) care as usual (CAU). The SMT comprised 12 sessions conducted by a psychologist. Complaints of burnout and distress were measured at baseline, and at 4, 7, and 10 months. Absenteeism was measured during the whole research period. Across treatment conditions, complaints and sickness absence reduced considerably between baseline and 4 months. Thereafter, complaints remained approximately stable, whereas sickness absence further reduced. Hardly any significant group difference emerged, and no consistent pattern could be discerned in favor of any treatment condition. In subgroups with low depressive complaints, though, individual SMT resulted in larger reductions of some complaints than CAU. In conclusion, this study adds to the evidence that CBT-based interventions as currently practiced are not successful in treating patients with clinical levels of work-related stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ion source brightness and nuclear microprobe applications

The ion source used to provide beams for nuclear microprobe systems must ideally satisfy several demands. Of primary importance is the beam brightness. It is clearly desirable to employ the brightest possible source in order to focus the smallest possible probe size on the specimen, with the highest possible beam current. Also important is the need for minimal maintenance, particularly for ion sources used inside single ended accelerators.

We report here on measurements conducted on the beam from the RF ion source in our 5U Pelletron accelerator. We have found that the beam brightness is highly heterogenous, with the paraxial rays about an order of magnitude brighter than the surrounding rays. This is desirable for nuclear microprobe operation because probe forming lens systems optimised for large demagnification magnitude can exploit the high brightness of the paraxial region. We find several other accelerators around the world also exhibit this characteristic.     

Catalytic asymmetric hydrogenation in micellar media with amphiphilic and non-amphiphilic ligands

The transfer of a homogeneous catalytic hydrogenation catalyst into an aqueous micellar system was investigated. In case of the asymmetric hydrogenation activity and enantioselectivity were enhanced in water due to the addition of surfactants. A variation of the microheterogenization in water was realized with new amphiphilic ligands derived from Brij (polyoxyethylene ethers) and PPM (4-diphenylphosphino-2-diphenylphosphinomethyl-pyrrolidine). The substrate could be solubilized in the micellar assemblies. Best results were observed in mixed micelles: the enantioselectivity achieved 96% ee. New practical aspects are given by use of polymerized surfactants which we prepared by polymerization of assemblies.     

Investigation of the thermal stability of nitroxide capped polystyrene by TGA and Py-GC/MS

The thermal stability of nitroxide capped polystyrene is examined by TGA and pyrolysis-GC/MS. As opposed to technical polystyrene, these polymers (M_n > 30000 g mol^–1) show a characteristic decomposition step at 230–250°C. The volatile product of this step is mainly styrene, which results from retropolymerization. For some PS-N adducts terminator fragments can be identified. Prolonged isothermal treatment of PS-N adducts at their step temperature yields polystyrene without nitroxides. The loss of molecular weight is in the range of technical PS by the same treatment, but the polymers keep a narrow molecular weight distribution.     

The Effect of Seasonal Variations,Covariations with Minerals and Forage Value on Itchgrass’ Foliar Silicification from Sudanian Benin

Silica (SiO ₂) in forage grasses has been found in reducing cell-wall digestibility. This study investigates whether: (i) the seasonal variability affects the silica and minerals accumulation and forage values of leaves of R. cochinchinensis and (ii) silica concentration is correlated with minerals and fodder value. In an itchgrass population selected in the W Biosphere Reserve, leaves were collected on 90 marked plants from May to October 2003 and 2004, at 15 days intervals except May, June and October. Some 300 g of fresh blades from the 3 ^rd most recently expanded leaves were oven dried and analyzed for dry mass, SiO ₂, ash, N, Na, Ca, P, K, and Mg. Digestible Nitrogen Matter (DNM) and Fodder Energetic Value (FEV) were calculated using the Demarquilly formula. Apart from SiO ₂, ash and forage value, data were log-transformed to restore homoscedasticity before statistical analyses. SiO ₂ ranges from 5.69 % to 9.95 %, i.e. varying 1.4 fold between May and October, reaching 1.75 fold at mid-September. SiO ₂ is positively related to Ca but negatively to K, P, N, DNM and FEV. The negative correlations suggest that SiO ₂ concentration in R. cochinchinensis could be reduced with a significant increase in energy and accumulation of important nutrients such as N, P and K. Therefore, leaf silicification and nutritive value relationship should be conclusive in the case of itchgrass.