Large electronic bandwidth in solution-processable pyrene crystals: The role of close-packed crystal structure

We examine the interdependence of structural and electronic properties of two substituted pyrene crystals by means of combined spectroscopic probes and density-functional theory calculations. One derivative features n-hexyl side groups, while the other one contains branched silanyl groups. Both derivatives form triclinic crystal structures when grown from solution, but the electronic dispersion behavior is significantly different due to differences in $\pi$-$\pi$ overlap along the $a$ crystal axis. Both systems display dispersion of 0.40-0.45 eV in the valence band, suggesting a high intrinsic hole mobility. However, the dispersion is primarily along the a-axis in the silanyl-substituted derivative, but less aligned with this crystal axis in the hexyl-substituted material. This is a direct consequence of the diferences in co-facial $\pi$ electron overlap revealed by the crystallographic studies. We find that photophysical defects, ascribed to excimer-like states, point to the importance of localized trap states. Substituted pyrenes are useful model systems to unravel the interplay of crystal structure and electronic properties in organic semiconductors.Comment: 25 pages, 8 figure

Stem cell characteristics of human trabecular bone-derived cells

Human trabecular bone-derived cells (HTBs) have been used for many years as osteoblast progenitors. In this study we tested whether HTBs have stem cell characteristics; that is, whether they are pluripotent and able to self-renew. We show that HTBs readily differentiate into osteoblasts, chondrocytes, and adipocytes if subjected to the appropriate differentiating conditions. Importantly, differentiation into these three lineages is maintained in single cell clones derived by limiting dilution, following expansion over more than 20 cumulative population doublings. We conclude that cultures of HTBs are equivalent to cultures of "mesenchymal stem cells" (MSCs) isolated from bone marrow. © 2002 by Elsevier Science Inc. All rights reserved

Effect of a health education intervention on intestinal parasitic infections in Bolivian children

Abstract Backgrounds Intestinal parasitic infections (IPI) are a major health issue for children of low- and middle-income countries. Water, sanitation and hygiene (WASH) practices are crucial for preventing IPI. The aim of the study was to evaluate the effects of a school-based health education intervention on handwashing behavior and IPI prevalence in children Methods This is a randomized intervention trial in 8 primary schools in rural communities over the course of 3 school years; preliminary results from the first two years of the trial are here presented. Schools were randomly selected and assigned in a 1:1 ratio to intervention or control (no intervention) groups. For each school year, the intervention included 14 school-based educational sessions and 2 skit events, involving children aged 8-12 years. Knowledge, attitude and practice questionnaire and handwashing at key events was assessed at the beginning and end of each school year. IPI prevalence was assessed with repeated cross-sectional parasitology surveys 12 months apart, involving a minimum of 50 children for each school Results At baseline, no significant differences between intervention and control schools were present in the proportion of children who washed their hands at key events (7.2% vs 9.3%, p = 0.28), in IPI (79.4% vs 75.3%, p = 0.3) and multiple parasitic infections (MPI) prevalences (47.6 vs. 38.6; p = 0.051). At the end of the second year, the percentage of children who washed their hands at key events was significantly higher in the intervention schools (75.4% vs 12.1%, p < 0.001), and the prevalence of IPI and MPI in the intervention schools were respectively about 25% and 15% lower than in the control schools (respectively, 42.9% vs 67.8%, p < 0.001; 16.1% vs 31.6%, p < 0.001) Conclusions A school-based health education intervention could achieve significant changes in hand-washing behaviors and reduction in the prevalence of IPI in children. The third year survey results are needed to confirm these findings Key messages An health education intervention on water, sanitation and hygiene (WASH) practices can reduce the risk of IPI infection in children. An health education intervention on water, sanitation and hygiene (WASH) practices could be configured as a sustainable long-term approach to intestinal parasitic infections control in children

Death kinetics of Escherichia coli in goat milk and Bacillus licheniformis in cloudberry jam treated by ohmic heating

In recent years, the world’s food industry has focused increasing attention on electrical techniques of food processing. Ohmic heating is one of these techniques that can be considered as a high temperature short time and a purely bulk heating method, having potential applications in processes such as blanching, evaporation and pasteurization in the food industry. However such technology would have to assure the microbiological safety obtained by the conventional cooking methods. Concerning this, the influence of heat treatment by ohmic and conventional technology on death kinetic parameters (D and z values) of Escherichia coli ATCC® 25922 was studied in goat milk. In ohmic treatment lower D values were obtained (D60ºC = 4.2 min, D63ºC = 1.9 min, D65ºC = 0.86 min) as compared to conventional treatment (D63ºC = 3.9 min, D65ºC = 3.5, D67ºC = 2.8 min, D75ºC = 1.5 min). The increase of temperature required for a ten fold decrease in D value was also lower in the ohmic inactivation (z = 8.4 ºC) comparing with the conventional inactivation (z = 23.1 ºC). The death kinetics for Bacillus licheniformis ATCC® 14580 spores in cloudberry jam were also studied under both types of heat inactivation (ohmic and conventional) and similar conclusions were drawn for the D values; lower D values were also obtained for ohmic treatment (D70ºC = 57.1 min, D75ºC = 25.2 min, D80ºC = 7.2 min) as compared to conventional treatment (D70ºC = 85.3 min, D75ºC = 51.0, D80ºC = 18.1 min, D85ºC = 6.0 min, D90ºC = 1.6 min). However, between the z values obtained for those treatments (z ohmic = 11.1 ºC and z conventional = 11.4 ºC) the differences were not significant. In general the results of present work indicate that the ohmic heating provides quicker death kinetics. This opens the perspective for shorter, less aggressive treatments

Efficacy and safety of single 40 mg/kg oral praziquantel in the treatment of schistosomiasis in preschool-age versus school-age children:An individual participant data meta-analysis

Better knowledge of the efficacy and safety of single 40 mg/kg oral praziquantel in preschool-age children is required, should preventive chemotherapy programs for schistosomiasis be expanded to include this age group.; We analyzed individual participant-level data from 16 studies (13 single-arm or cohort studies and three randomized trials), amounting to 683 preschool-age children (aged <6 years) and 2,010 school-age children (aged 6-14 years). Children had a documented Schistosoma mansoni or S. haematobium infection, were treated with single 40 mg/kg oral praziquantel, and assessed between 21 and 60 days post-treatment. Efficacy was expressed as arithmetic mean and individual egg reduction rate (ERR) and meta-analyzed using general linear models and mixed models. Safety was summarized using reported adverse events (AEs).; Preschool-age children had significantly lower baseline Schistosoma egg counts and more losses to follow-up compared to school-age children. No difference in efficacy was found between preschool- and school-age children using a general linear model of individual-participant ERR with baseline log-transformed egg count as covariate and study, age, and sex as fixed variables, and a mixed model with a random effect on the study. Safety was reported in only four studies (n = 1,128 individuals); few AEs were reported in preschool-age children 4 and 24 hours post-treatment as well as at follow-up. Three severe but not serious AEs were recorded in school-age children during follow-up.; There is no indication that single 40 mg/kg oral praziquantel would be less efficacious and safe in preschool-age children compared to school-age children, with the caveat that only few randomized comparisons exist between the two age groups. Preventive chemotherapy might therefore be extended to preschool-age children, with proper monitoring of its efficacy and safety

Genetic architecture of the APM1 gene and its influence on adiponectin plasma levels and parameters of the metabolic syndrome in 1,727 healthy Caucasians

Copyright: Copyright 2008 Elsevier B.V., All rights reserved.The associations of the adiponectin (APM1) gene with parameters of the metabolic syndrome are inconsistent. We performed a systematic investigation based on fine-mapped single nucleotide polymorphisms (SNPs) highlighting the genetic architecture and their role in modulating adiponectin plasma concentrations in a particularly healthy population of 1,727 Caucasians avoiding secondary effects from disease processes. Genotyping 53 SNPs (average spacing of 0.7 kb) in the APM1 gene region in 81 Caucasians revealed a two-block linkage disequilibrium (LD) structure and enabled comprehensive tag SNP selection. We found particularly strong associations with adiponectin concentrations for 11 of the 15 tag SNPs in the 1,727 subjects (five P values <0.0001). Haplotype analysis provided a thorough differentiation of adiponectin concentrations with 9 of 17 haplotypes showing significant associations (three P values <0.0001). No significant association was found for any SNP with the parameters of the metabolic syndrome. We observed a two-block LD structure of APM1 pointing toward at least two independent association signals, one including the promoter SNPs and a second spanning the relevant exons. Our data on a large number of healthy subjects suggest a clear modulation of adiponectin concentrations by variants of APM1, which are not merely a concomitant effect in the course of type 2 diabetes or coronary artery disease.publishersversionPeer reviewe

Air–liquid interface cultures enhance the oxygen supply and trigger the structural and functional differentiation of intestinal porcine epithelial cells (IPEC)

The specific function of the epithelium as critical barrier between the intestinal lumen and the organism’s internal microenvironment is reflected by permanent maintenance of intercellular junctions and cellular polarity. The intestinal epithelial cells are responsible for absorption of nutritional components, facing mechanical stress and a changing oxygen supplementation via blood stream. Oxygen itself can regulate the barrier and the absorptive function of the epithelium. Therefore, we compared the dish cell culture, the transwell-like membrane culture and the oxygen enriched air–liquid interface (ALI) culture. We demonstrated strong influence of the different culture conditions on morphology and function of intestinal porcine epithelial cell lines in vitro. ALI culture resulted in a significant increase in cell number, epithelial cell layer thickness and expression as well as apical localisation of the microvilli-associated protein villin. Remarkable similarities regarding the morphological parameters were observed between ALI cultures and intestinal epithelial cells in vivo. Furthermore, the functional analysis of protein uptake and degradation by the epithelial cells demonstrated the necessity of sufficient oxygen supply as achieved in ALI cultures. Our study is the first report providing marked evidence that optimised oxygen supply using ALI cultures directly affects the morphological differentiation and functional properties of intestinal epithelial cells in vitro