A kinetic and equilibrium analysis of silicon carbide chemical vapor deposition on monofilaments

Chemical kinetics of atmospheric pressure silicon carbide (SiC) chemical vapor deposition (CVD) from dilute silane and propane source gases in hydrogen is numerically analyzed in a cylindrical upflow reactor designed for CVD on monofilaments. The chemical composition of the SiC deposit is assessed both from the calculated total fluxes of carbon and silicon and from chemical equilibrium considerations for the prevailing temperatures and species concentrations at and along the filament surface. The effects of gas and surface chemistry on the evolution of major gas phase species are considered in the analysis

Convection and chemistry effects in CVD: A 3-D analysis for silicon deposition

The computational fluid dynamics code FLUENT has been adopted to simulate the entire rectangular-channel-like (3-D) geometry of an experimental CVD reactor designed for Si deposition. The code incorporated the effects of both homogeneous (gas phase) and heterogeneous (surface) chemistry with finite reaction rates of important species existing in silane dissociation. The experiments were designed to elucidate the effects of gravitationally-induced buoyancy-driven convection flows on the quality of the grown Si films. This goal is accomplished by contrasting the results obtained from a carrier gas mixture of H2/Ar with the ones obtained from the same molar mixture ratio of H2/He, without any accompanying change in the chemistry. Computationally, these cases are simulated in the terrestrial gravitational field and in the absence of gravity. The numerical results compare favorably with experiments. Powerful computational tools provide invaluable insights into the complex physicochemical phenomena taking place in CVD reactors. Such information is essential for the improved design and optimization of future CVD reactors

Voluntary wheel running augments aortic L-arginine transport and endothelial function in rats with chronic kidney disease

Reduced nitric oxide (NO) synthesis contributes to risk for cardiovascular disease in chronic kidney disease (CKD). Vascular uptake of the NO precursor L-arginine (ARG) is attenuated in rodents with CKD, resulting in reduced substrate availability for NO synthesis and impaired vascular function. We tested the effect of 4 wk of voluntary wheel running (RUN) and/or ARG supplementation on endothelium-dependent relaxation (EDR) in rats with CKD. Twelve-week-old male Sprague-Dawley rats underwent 5/6 ablation infarction surgery to induce CKD, or SHAM surgery as a control. Beginning 4 wk following surgery, CKD animals either remained sedentary (SED) or received one of the following interventions: supplemental ARG, RUN, or combined RUN + ARG. Animals were euthanized 8 wk after surgery, and EDR was assessed. EDR was significantly impaired in SED vs. SHAM animals after 8 wk, in response to ACh (10(-9)-10(-5) M) as indicated by a reduced area under the curve (AUC; 44.56 +/- 9.01 vs 100 +/- 4.58, P \u3c 0.05) and reduced maximal response (E-max; 59.9 +/- 9.67 vs. 94.31 +/- 1.27%, P \u3c 0.05). AUC was not improved by ARG treatment but was significantly improved above SED animals in both RUN and RUN + ARG-treated animals. Maximal relaxation was elevated above SED in RUN + ARG animals only. L-[H-3] arginine uptake was impaired in both SED and ARG animals and was improved in RUN and RUN + ARG animals. The results suggest that voluntary wheel running is an effective therapy to improve vascular function in CKD and may be more beneficial when combined with L-arginine

Voluntary Wheel Running Augments Vascular Function in Rats with Chronic Kidney Disease

Please view abstract in the attached PDF file

Increased vulnerability of rural children on antiretroviral therapy attending public health facilities in South Africa: a retrospective cohort study

BACKGROUND: A large proportion of the 340,000 HIV-positive children in South Africa live in rural areas, yet there is little sub-Saharan data comparing rural paediatric antiretroviral therapy (ART) programme outcomes with urban facilities. We compared clinical, immunological and virological outcomes between children at seven rural and 37 urban facilities across four provinces in South Africa. METHODS: We conducted a retrospective cohort study of routine data of children enrolled on ART between November 2003 and March 2008 in three settings, namely: urban residence and facility attendance (urban group); rural residence and facility attendance (rural group); and rural residents attending urban facilities (rural/urban group). Outcome measures were: death, loss to follow up (LTFU), virological suppression, and changes in CD4 percentage and weight-for-age-z (WAZ) scores. Kaplan-Meier estimates, logrank tests, multivariable Cox regression and generalized estimating equation models were used to compare outcomes between groups. RESULTS: In total, 2332 ART-naive children were included, (1727, 228 and 377 children in the urban, rural and rural/urban groups, respectively). At presentation, rural group children were older (6.7 vs. 5.6 and 5.8 years), had lower CD4 cell percentages (10.0% vs. 12.8% and 12.7%), lower WAZ scores (-2.06 vs. -1.46 and -1.41) and higher proportions with severe underweight (26% vs.15% and 15%) compared with the urban and rural/urban groups, respectively. Mortality was significantly higher in the rural group and LTFU significantly increased in the rural/urban group. After 24 months of ART, mortality probabilities were 3.4% (CI: 2.4-4.8%), 7.7% (CI: 4.5-13.0%) and 3.1% (CI: 1.7-5.6%) p = 0.0137; LTFU probabilities were 11.5% (CI: 9.3-14.0%), 8.8% (CI: 4.5-16.9%) and 16.6% (CI: 12.4-22.6%), p = 0.0028 in the urban, rural and rural/urban groups, respectively. The rural group had an increased adjusted mortality probability, adjusted hazards ratio 2.41 (CI: 1.25-4.67) and the rural/urban group had an increased adjusted LTFU probability, aHR 2.85 (CI: 1.41-5.79). The rural/urban group had a decreased adjusted probability of virological suppression compared with the urban group at any timepoint on treatment, adjusted odds ratio 0.67 (CI: 0.48-0.93). CONCLUSIONS: Rural HIV-positive children are a vulnerable group, exhibiting delayed access to ART and an increased risk of poor outcomes while on ART. Expansion of rural paediatric ART programmes, with future research exploring improvements to rural health system effectiveness, is required

MannDB: A microbial annotation database for protein characterization

MannDB was created to meet a need for rapid, comprehensive automated protein sequence analyses to support selection of proteins suitable as targets for driving the development of reagents for pathogen or protein toxin detection. Because a large number of open-source tools were needed, it was necessary to produce a software system to scale the computations for whole-proteome analysis. Thus, we built a fully automated system for executing software tools and for storage, integration, and display of automated protein sequence analysis and annotation data. MannDB is a relational database that organizes data resulting from fully automated, high-throughput protein-sequence analyses using open-source tools. Types of analyses provided include predictions of cleavage, chemical properties, classification, features, functional assignment, post-translational modifications, motifs, antigenicity, and secondary structure. Proteomes (lists of hypothetical and known proteins) are downloaded and parsed from Genbank and then inserted into MannDB, and annotations from SwissProt are downloaded when identifiers are found in the Genbank entry or when identical sequences are identified. Currently 36 open-source tools are run against MannDB protein sequences either on local systems or by means of batch submission to external servers. In addition, BLAST against protein entries in MvirDB, our database of microbial virulence factors, is performed. A web client browser enables viewing of computational results and downloaded annotations, and a query tool enables structured and free-text search capabilities. When available, links to external databases, including MvirDB, are provided. MannDB contains whole-proteome analyses for at least one representative organism from each category of biological threat organism listed by APHIS, CDC, HHS, NIAID, USDA, USFDA, and WHO. MannDB comprises a large number of genomes and comprehensive protein sequence analyses representing organisms listed as high-priority agents on the websites of several governmental organizations concerned with bio-terrorism. MannDB provides the user with a BLAST interface for comparison of native and non-native sequences and a query tool for conveniently selecting proteins of interest. In addition, the user has access to a web-based browser that compiles comprehensive and extensive reports

The wellbeing of infants exposed to Buprenorphine via breast milk at 4 weeks of age

Background: Buprenorphine has been available in Australia since 2000 as an alternative pharmacotherapy to methadone for the treatment of opioid dependence. However, there is little information in the literature regarding the effect of buprenorphine on the wellbeing of infants exposed to buprenorphine via breast milk, following discharge from hospital. Objective: The aim of the present study was to examine the wellbeing of infants exposed to buprenorphine via breast milk up to 4 weeks postnatal. Methods: Approximately 4 weeks after birth, information on the feeding and sleeping patterns, skin color, infant elimination patterns and hydration, and Neonatal Abstinence Scores of infants (n = 7) exposed to buprenorphine via breast milk was collected via both observation and documentation. Results: Infants were progressing well, with normal sleep patterns and skin color, and 2 mothers had minor concerns regarding infant elimination patterns. Four infants were exclusively breastfed and 3 were receiving a supplement, with a range of 260 to 700 mL of formula over 24 hours. The sleep patterns following feeding ranged from 1.55 to 3.33 hours, with a median of 2.12 hours. Conclusion: No adverse effects were detected in infants exposed to buprenorphine via breast milk up to 4 weeks postnatal. Further research using larger samples to assess possible developmental effects over longer periods of time is required

Percentile reference values for anthropometric body composition indices in European children from the IDEFICS study

INTRODUCTION: To characterise the nutritional status in children with obesity or wasting conditions, European anthropometric reference values for body composition measures beyond the body mass index (BMI) are needed. Differentiated assessment of body composition in children has long been hampered by the lack of appropriate references. OBJECTIVES: The aim of our study is to provide percentiles for body composition indices in normal weight European children, based on the IDEFICS cohort (Identification and prevention of Dietary-and lifestyle-induced health Effects in Children and infantS). METHODS: Overall 18 745 2.0-10.9-year-old children from eight countries participated in the study. Children classified as overweight/obese or underweight according to IOTF (N = 5915) were excluded from the analysis. Anthropometric measurements (BMI (N = 12 830); triceps, subscapular, fat mass and fat mass index (N = 11 845-11 901); biceps, suprailiac skinfolds, sum of skinfolds calculated from skinfold thicknesses (N = 8129-8205), neck circumference (N = 12 241); waist circumference and waist-to-height ratio (N = 12 381)) were analysed stratified by sex and smoothed 1st, 3rd, 10th, 25th, 50th, 75th, 90th, 97th and 99th percentile curves were calculated using GAMLSS. RESULTS: Percentile values of the most important anthropometric measures related to the degree of adiposity are depicted for European girls and boys. Age-and sex-specific differences were investigated for all measures. As an example, the 50th and 99th percentile values of waist circumference ranged from 50.7-59.2 cm and from 51.3-58.7 cm in 4.5-to < 5.0-year-old girls and boys, respectively, to 60.6-74.5 cm in girls and to 59.9-76.7 cm in boys at the age of 10.5-10.9 years. CONCLUSION: The presented percentile curves may aid a differentiated assessment of total and abdominal adiposity in European children

Lactobacillus casei strain GG in the treatment of infants with acute watery diarrhea: A randomized, double-blind, placebo controlled clinical trial [ISRCTN67363048]

BACKGROUND: Adjuvant therapy to ORT with probiotic bacteria for infants with acute watery diarrhea has been under active investigation. Most studies have been done in the developed world showing benefit only for viral mild gastroenteritis. We evaluated the effect of a milk formula containing one billion (10(9)) cfu/ml of Lactobacillus casei strain GG (LGG) upon duration and severity of diarrhea in infants in an environment with more severe acute diarrhea, where etiologic agents other than rotavirus are involved more frequently, and where mixed infections are more prevalent. METHODS: Male infants aged 3–36 months brought for treatment of acute watery diarrhea of less than 48 hours were eligible. After rehydration was completed with the WHO's oral rehydration solution, patients were randomly assigned to receive a milk formula either containing LGG or not. Stool volume was periodically measured using a devise suited to collect stools separate from urine. Duration of diarrhea was estimated based on stools physical characteristics. RESULTS: Eighty nine patients received the placebo milk formula and ninety received the LGG containing formula. Both groups were comparable in their baseline characteristics. Total stool output was significantly larger (p = 0.047) in the LGG group (247.8 ml/kg) than in the placebo group (195.0 ml/kg). No significant differences were found in duration of diarrhea (58.5 hours with LGG vs. 50.4 hours with placebo), rate of treatment failure (21.1% with LGG vs. 18.0% with placebo), and proportion of patients with unresolved diarrhea after 120 hours (12.2% with LGG vs. 12.5% with placebo). The rate of stools with reducing substances after 24 hours of treatment increased significantly in both groups (from 41.4% to 72.2% with LGG and from 45.9% to 68.0% with placebo). CONCLUSION: This study did not show a positive effect of LGG on the clinical course of acute watery diarrhea. Positive beneficial effects of LGG, as had been reported elsewhere, could have been masked in our study by worsening diarrhea due to transient lactose malabsorption. Further studies with low-lactose or non-lactose conveyors of LGG are desirable