Separation of Steviol Glycosides by Hydrophilic Liquid Interaction Chromatography

Stevia rebaudiana Bertoni contains several steviol glycosides with sweet flavour. They all are sweeter than sucrose (up to factor 450). The various steviol glycosides are difficult to separate by reversed-phase chromatography. In this paper, five different hydrophilic liquid interaction chromatography columns are characterized using isocratic elution (5–20% water in acetonitrile with buffer or formic acid). Separation of the steviol glycosides is possible with all but one of the tested columns, but the robustness of the separation against changes of buffer concentration and percentage of water differ. Aqueous percentage and ion strength of the eluent are the main factors to be optimized in method development.     

Effect of processing for saponin removal on fungal contamination of quinoa seeds (Chenopodium quinoa Willd.)

Incidence of fungal contamination of quinoa seeds from three locations (Salar de Uyuni, Bolivia; Salta and Tucumán provinces, Argentina) was analyzed in samples with and without treatment to remove saponins (wet method). In processed samples, the percentage of infection was reduced. Distribution of the different fungal genera was not homogeneous in the three locations (p<0.05), although Penicillium and Aspergillus were the most prevalent contaminants, regardless the geographic origin of the samples. Other genera, such as Eurotium, Fusarium, Phoma, Ulocladium, Mucor and Rhizopus were less frequently isolated. Absidia, Alternaria, Cladosporium, Dreschlera, Epicoccum and Monascus were sporadically encountered. Significant differences (p<0.05) in the distribution of fungal genera in samples with and without saponins from each location were observed. In all cases, processing caused a decrease of Aspergillus incidence, while increased the proportion of Penicillium, Eurotium, Mucor and Rhizopus indicating that these genera were part of the internal mycota. A. flavus and A. niger were the dominating species of genus Aspergillus. A similar pattern of prevalent Penicillium species was observed in samples with and without saponins, since P. aurantiogriseum, P.chrysogenum, P. citrinum and P. crustosum were always present in high number, although their relative density was variable according to the geographic origin of samples. Mycotoxin-producing ability of most representative species was also determined. Toxigenic strains of A. flavus (aflatoxins and cyclopiazonic acid), A. parasiticus (aflatoxins), P. citrinum (citrinin) and P. griseofulvum (cyclopiazonic acid) were found. None of the A. niger isolates was ochratoxin A producer. The above mentioned mycotoxins were not detected in the samples analyzed.     

Fitting in and feeling fine: Conformity and coping motives as mediators of the relationship between social anxiety and problematic drinking.

The present research was conducted to clarify the relationships among social anxiety, alcohol consumption, alcohol-related problems, and negative-reinforcement drinking motives among college students. Heavy drinking students (N = 316, 53.80% female) completed self-report measures of social anxiety, alcohol consumption, alcohol-related problems, and drinking motives. Findings indicated that students higher in social anxiety consumed less alcohol but experienced more negative consequences. Moreover, the relationship between social anxiety and negative consequences was mediated by coping and conformity drinking motives in addition to alcohol consumption. In the context of social anxiety, the current research demonstrates the importance of examining problematic drinking as distinct constructs: alcohol consumption and negative consequences. Findings are also discussed in terms of implications for interventions with socially anxious students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of Bone Microstructure by Micro CT in C57BL/6J Mice for Sex-Specific Differentiation

It remains uncertain which skeletal sites and parameters should be analyzed in rodent studies evaluating bone health and disease. In this cross-sectional mouse study using micro-computed tomography (µCT), we explored: (1) which microstructural parameters can be used to discriminate female from male bones and (2) whether it is meaningful to evaluate more than one bone site. Microstructural parameters of the trabecular and/or cortical compartments of the femur, tibia, thoracic and lumbar vertebral bodies, and skull were evaluated by µCT in 10 female and 10 male six-month-old C57BL/6J mice. The trabecular number (TbN) was significantly higher, while the trabecular separation (TbSp) was significantly lower in male compared to female mice at all skeletal sites assessed. Overall, bone volume/tissue volume (BV/TV) was also significantly higher in male vs. female mice (except for the thoracic spine, which did not differ by sex). Most parameters of the cortical bone microstructure did not differ between male and female mice. BV/TV, TbN, and TbSp at the femur, and TbN and TbSp at the tibia and lumbar spine could fully (100%) discriminate female from male bones. Cortical thickness (CtTh) at the femur was the best parameter to detect sex differences in the cortical compartment (AUC = 0.914). In 6-month-old C57BL/6J mice, BV/TV, TbN, and TbSp can be used to distinguish male from female bones. Whenever it is not possible to assess multiple bone sites, we propose to evaluate the bone microstructure of the femur for detecting potential sex differences.     

Interactive minds: A facilitative setting for wisdom-related performance?

Two goals guided the present study: to develop ecologically relevant and functional interactive-minds settings for the assessment of wisdom-related performance and to investigate whether and under which conditions such settings would facilitate higher levels of wisdom-related performance. After baseline assessment of wisdom-related performance, a sample of 122 natural dyads (244 participants), ranging in age from 20 to 70 years, were randomly assigned to 5 experimental conditions. These conditions varied in the degree to which they were judged to be ecologically relevant and functional and involved the interaction of minds. It was found that performance settings that were judged to be ecologically relevant and functional and provided for actual or "virtual" (internal) interaction of minds increased wisdom-related performance levels by 1 SD. In addition, older adults profited more than younger adults from 1 setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Initial analyses of naltriben, a delta opioid receptor antagonist, as a putative medicine for treating cocaine abuse.

The authors explored naltriben's (NTB, a delta opioid antagonist) potential to be a pharmacotherapy for cocaine abuse. NTB (3–6 mg/kg) reduced rats' (Rattus norvegicus) intravenous, self-administration of cocaine, daily, across 5 days. NTB did not, however, interfere with rats' pressing for water. NTB (3 mg/kg) blocked cocaine's facilitation of pressing for brain stimulation, daily, for 5 days. As doses of NTB were explored, it was found that 10 mg/kg of NTB was lethal for about one third of the rats. Smaller doses (e.g., 3 mg/kg) gave some indications of toxicity as indexed by NTB's tendency to reduce pressing for brain stimulation by itself. NTB (3 mg/kg) induced a mild conditioned taste aversion but had no negative effects on rats' ability to learn and remember a sequence of mazes. Taken together, these results lead to the suggestion that opioidergic processes play an important role in mediating cocaine's reinforcement. Although NTB may not be the ideal opioid antagonist for treating people, it has many positive properties supporting further investigation of opioid antagonists as agents for treating cocaine addiction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis of a mesoporous material from two natural sources

Mesoporous materials were obtained from two natural silica sources, diatomite and pumicite, under hydrothermal conditions, autogenic pressure and in presence of the surfactant cetyltrimethylammonium bromide (CTAB) as the template. Using diatomite, a temperature of 383 K and the following molar ratios in the initial reaction gel: SiO₂/Al₂O₃ = 8.86; CTAB/SiO₂ = 0.1; Na₂O/SiO₂ = 0.10–0.25 and H₂O/Na₂O = 250–300, the mesoporous material MCM‐41 was obtained in a reaction time of 48 h. When pumicite was used, a mesoporous material was obtained in a reaction time of 96 h, a reaction temperature of 423 K and an initial reaction gel with the following molar ratios: SiO₂/Al₂O₃ = 8.86; CTAB/SiO₂ = 0.1; Na₂O/SiO₂ = 0.25 and H₂O/Na₂O = 330. Copyright © 2006 Society of Chemical Industry