Psychometric properties of an instrument to measure the clinical learning environment

Objectives: The clinical learning environment is an influential factor in work-based learning. Evaluation of this environment gives insight into the educational functioning of clinical departments. The Postgraduate Hospital Educational Environment Measure (PHEEM) is an evaluation tool consisting of a validated questionnaire with 3 subscales. In this paper we further investigate the psychometric properties of the PHEEM. We set out to validate the 3 subscales and test the reliability of the PHEEM for both clerks (clinical medical students) and registrars (specialists in training). Methods: Clerks and registrars from different hospitals and specialties filled out the PHEEM. To investigate the construct validity of the 3 subscales, we used an exploratory factor analysis followed by varimax rotation, and a cluster analysis known as Mokken scale analysis. We estimated the reliability of the questionnaire by means of variance components according to generalisability theory. Results: A total of 256 clerks and 339 registrars filled out the questionnaire. The exploratory factor analysis plus varimax rotation suggested a 1-dimensional scale. The Mokken scale analysis confirmed this result. The reliability analysis showed a reliable outcome for 1 department with 14 clerks or 11 registrars. For multiple departments 3 respondents combined with 10 departments provide a reliable outcome for both groups. Discussion: The PHEEM is a questionnaire measuring 1 dimension instead of the hypothesised 3 dimensions. The sample size required to achieve a reliable outcome is feasible. The instrument can be used to evaluate both single and multiple departments for both clerks and registrars. © 2007 Blackwell Publishing Ltd

Bradyrhizobium japonicum and soybean symbiotic response to glyphosate in glyphosate-tolerant soybeans

Soybean (Glycine max) grain contains approximately 40% protein and 6.5% nitrogen (N) on an elemental basis. Therefore, the plant requires an abundant N supply throughout its life cycle, and symbiotic N fixation of soybean with Bradyrhizobium japonicum provides 40 to 85% of the soybean N. Although soybean cultivars have been genetically engineered to withstand the herbicide glyphosate, B. japonicum grown in culture is sensitive to glyphosate. We hypothesized that glyphosate applied to glyphosate-tolerant soybean would inhibit nodulation by B. japonicum unless B. japonicum could also be selected for glyphosate tolerance. Cultures of B. japonicum were challenged with sublethal doses of glyphosate, and individual colonies were selected for growth in the presence of glyphosate. Of the 40 isolates that were originally selected for glyphosate tolerance, all isolates in subsequent experiments had similar sensitivity to glyphosate as wild-type B. japonicum. To determine if glyphosate affected B. japonicum in plants, soybean seeds were imbibed with differing levels of glyphosate and water and then planted and inoculated with B. japonicum. After several weeks of growth the plants were harvested and nodules were scanned and analyzed by digital imagery. Glyphosate application to glyphosate-tolerant soybean did not affect the ability of B. japonicum to form nodules and fix nitrogen. These data do not agree with previous responses of small soybean plants sprayed with glyphosate, which showed delayed nodulation and decreased nodule size. It may be that the dosage applied to plants and the timing of the application affect the response of glyphosate on symbiotic effectiveness

Integration of microRNA changes in vivo identifies novel molecular features of muscle insulin resistance in type 2 diabetes

Skeletal muscle insulin resistance (IR) is considered a critical component of type II diabetes, yet to date IR has evaded characterization at the global gene expression level in humans. MicroRNAs (miRNAs) are considered fine-scale rheostats of protein-coding gene product abundance. The relative importance and mode of action of miRNAs in human complex diseases remains to be fully elucidated. We produce a global map of coding and non-coding RNAs in human muscle IR with the aim of identifying novel disease biomarkers. We profiled >47,000 mRNA sequences and >500 human miRNAs using gene-chips and 118 subjects (n = 71 patients versus n = 47 controls). A tissue-specific gene-ranking system was developed to stratify thousands of miRNA target-genes, removing false positives, yielding a weighted inhibitor score, which integrated the net impact of both up- and down-regulated miRNAs. Both informatic and protein detection validation was used to verify the predictions of in vivo changes. The muscle mRNA transcriptome is invariant with respect to insulin or glucose homeostasis. In contrast, a third of miRNAs detected in muscle were altered in disease (n = 62), many changing prior to the onset of clinical diabetes. The novel ranking metric identified six canonical pathways with proven links to metabolic disease while the control data demonstrated no enrichment. The Benjamini-Hochberg adjusted Gene Ontology profile of the highest ranked targets was metabolic (P < 7.4 × 10-8), post-translational modification (P < 9.7 × 10-5) and developmental (P < 1.3 × 10-6) processes. Protein profiling of six development-related genes validated the predictions. Brain-derived neurotrophic factor protein was detectable only in muscle satellite cells and was increased in diabetes patients compared with controls, consistent with the observation that global miRNA changes were opposite from those found during myogenic differentiation. We provide evidence that IR in humans may be related to coordinated changes in multiple microRNAs, which act to target relevant signaling pathways. It would appear that miRNAs can produce marked changes in target protein abundance in vivo by working in a combinatorial manner. Thus, miRNA detection represents a new molecular biomarker strategy for insulin resistance, where micrograms of patient material is needed to monitor efficacy during drug or life-style interventions

Thermoelectric properties of lead chalcogenide core-shell nanostructures

We present the full thermoelectric characterization of nanostructured bulk PbTe and PbTe-PbSe samples fabricated from colloidal core-shell nanoparticles followed by spark plasma sintering. An unusually large thermopower is found in both materials, and the possibility of energy filtering as opposed to grain boundary scattering as an explanation is discussed. A decreased Debye temperature and an increased molar specific heat are in accordance with recent predictions for nanostructured materials. On the basis of these results we propose suitable core-shell material combinations for future thermoelectric materials of large electric conductivities in combination with an increased thermopower by energy filtering.Comment: 12 pages, 8 figure

Thermal Flammable Gas Production from Bulk Vitrification Feed

The baseline bulk-vitrification (BV) process (also known as in-container vitrification ICV™) includes a mixer/dryer to convert liquid low-activity waste (LAW) into a dried, blended feed for vitrification. Feed preparation includes blending LAW with glass-forming minerals (GFMs) and cellulose and drying the mixture to a suitable dryness, consistency, and particle size for transport to the ICVTM container. The cellulose is to be added to the BV feed at a rate sufficient to destroy 75% of the nitrogen present as nitrate or nitrite. Concern exists that flammable gases may be produced during drying operations at levels that could pose a risk. The drying process is conducted under vacuum in the temperature range of 60 to 80°C. These flammable gases could be produced either through thermal decomposition of cellulose or waste organics or as a by-product of the reaction of cellulose and/or waste organics with nitrate or the postulated small amount of nitrite present in the waste. To help address the concern about flammable gas production during drying, the Pacific Northwest National Laboratory (PNNL) performed studies to identify the gases produced at dryer temperatures and at possible process upset conditions. Studies used a thermogravimetric analyzer (TGA) up to 525°C and isothermal testing up to 120°C to determine flammable gas production resulting from the cellulose and organic constituents in bulk vitrification feed. This report provides the results of those studies to determine the effects of cellulose and waste organics on flammable gas evolutio

Dysregulation of a novel miR-23b/27b-p53 axis impairs muscle stem cell differentiation of humans with type 2 diabetes

Objective: MicroRNAs (miRNAs) are increasingly recognized as fine-tuning regulators of metabolism, and are dysregulated in several disease conditions. With their capacity to rapidly change gene expression, miRNAs are also important regulators of development and cell differentiation. In the current study, we describe an impaired myogenic capacity of muscle stem cells isolated from humans with type 2 diabetes (T2DM) and assess whether this phenotype is regulated by miRNAs. Methods: We measured global miRNA expression during in vitro differentiation of muscle stem cells derived from T2DM patients and healthy controls. Results: The mir-23b/27b cluster was downregulated in the cells of the patients, and a pro-myogenic effect of these miRNAs was mediated through the p53 pathway, which was concordantly dysregulated in the muscle cells derived from humans with T2DM. Conclusions: Our results indicate that we have identified a novel pathway for coordination of myogenesis, the miR-23b/27b-p53 axis that, when dysregulated, potentially contributes to a sustained muscular dysfunction in T2DM

First detection of NH3 (1,0 - 0,0) from a low mass cloud core: On the low ammonia abundance of the rho Oph A core

Odin has successfully observed the molecular core rho Oph A in the 572.5 GHz rotational ground state line of ammonia, NH3 (J,K = 1,0 - 0,0). The interpretation of this result makes use of complementary molecular line data obtained from the ground (C17O and CH3OH) as part of the Odin preparatory work. Comparison of these observations with theoretical model calculations of line excitation and transfer yields a quite ordinary abundance of methanol, X(CH3OH) = 3e-9. Unless NH3 is not entirely segregated from C17O and CH3OH, ammonia is found to be significantly underabundant with respect to typical dense core values, viz. X(NH3) = 8e-10.Comment: 4 pages, 2 figures, 2 tables, to appear in Astron. Astrophys. Letter