Thermodynamic Behavior of a Model Covalent Material Described by the Environment-Dependent Interatomic Potential

Using molecular dynamics simulations we study the thermodynamic behavior of a single-component covalent material described by the recently proposed Environment-Dependent Interatomic Potential (EDIP). The parameterization of EDIP for silicon exhibits a range of unusual properties typically found in more complex materials, such as the existence of two structurally distinct disordered phases, a density decrease upon melting of the low-temperature amorphous phase, and negative thermal expansion coefficients for both the crystal (at high temperatures) and the amorphous phase (at all temperatures). Structural differences between the two disordered phases also lead to a first-order transition between them, which suggests the existence of a second critical point, as is believed to exist for amorphous forms of frozen water. For EDIP-Si, however, the unusual behavior is associated not only with the open nature of tetrahedral bonding but also with a competition between four-fold (covalent) and five-fold (metallic) coordination. The unusual behavior of the model and its unique ability to simulation the liquid/amorphous transition on molecular-dynamics time scales make it a suitable prototype for fundamental studies of anomalous thermodynamics in disordeered systems.Comment: 48 pages (double-spaced), 13 figure

The impacts of environmental warming on Odonata: a review

Climate change brings with it unprecedented rates of increase in environmental temperature, which will have major consequences for the earth's flora and fauna. The Odonata represent a taxon that has many strong links to this abiotic factor due to its tropical evolutionary history and adaptations to temperate climates. Temperature is known to affect odonate physiology including life-history traits such as developmental rate, phenology and seasonal regulation as well as immune function and the production of pigment for thermoregulation. A range of behaviours are likely to be affected which will, in turn, influence other parts of the aquatic ecosystem, primarily through trophic interactions. Temperature may influence changes in geographical distributions, through a shifting of species' fundamental niches, changes in the distribution of suitable habitat and variation in the dispersal ability of species. Finally, such a rapid change in the environment results in a strong selective pressure towards adaptation to cope and the inevitable loss of some populations and, potentially, species. Where data are lacking for odonates, studies on other invertebrate groups will be considered. Finally, directions for research are suggested, particularly laboratory studies that investigate underlying causes of climate-driven macroecological patterns

TCERG1L allelic variation is associated with cisplatin-induced hearing loss in childhood cancer, a PanCareLIFE study.

In children with cancer, the heterogeneity in ototoxicity occurrence after similar treatment suggests a role for genetic susceptibility. Using a genome-wide association study (GWAS) approach, we identified a genetic variant in TCERG1L (rs893507) to be associated with hearing loss in 390 non-cranial irradiated, cisplatin-treated children with cancer. These results were replicated in two independent, similarly treated cohorts (n = 192 and 188, respectively) (combined cohort: P = 5.3 × 10-10, OR 3.11, 95% CI 2.2-4.5). Modulating TCERG1L expression in cultured human cells revealed significantly altered cellular responses to cisplatin-induced cytokine secretion and toxicity. These results contribute to insights into the genetic and pathophysiological basis of cisplatin-induced ototoxicity

Comparative (Meta)genomic Analysis and Ecological Profiling of Human Gut-Specific Bacteriophage φB124-14

Bacteriophage associated with the human gut microbiome are likely to have an important impact on community structure and function, and provide a wealth of biotechnological opportunities. Despite this, knowledge of the ecology and composition of bacteriophage in the gut bacterial community remains poor, with few well characterized gut-associated phage genomes currently available. Here we describe the identification and in-depth (meta)genomic, proteomic, and ecological analysis of a human gut-specific bacteriophage (designated φB124-14). In doing so we illuminate a fraction of the biological dark matter extant in this ecosystem and its surrounding eco-genomic landscape, identifying a novel and uncharted bacteriophage gene-space in this community. φB124-14 infects only a subset of closely related gut-associated Bacteroides fragilis strains, and the circular genome encodes functions previously found to be rare in viral genomes and human gut viral metagenome sequences, including those which potentially confer advantages upon phage and/or host bacteria. Comparative genomic analyses revealed φB124-14 is most closely related to φB40-8, the only other publically available Bacteroides sp. phage genome, whilst comparative metagenomic analysis of both phage failed to identify any homologous sequences in 136 non-human gut metagenomic datasets searched, supporting the human gut-specific nature of this phage. Moreover, a potential geographic variation in the carriage of these and related phage was revealed by analysis of their distribution and prevalence within 151 human gut microbiomes and viromes from Europe, America and Japan. Finally, ecological profiling of φB124-14 and φB40-8, using both gene-centric alignment-driven phylogenetic analyses, as well as alignment-free gene-independent approaches was undertaken. This not only verified the human gut-specific nature of both phage, but also indicated that these phage populate a distinct and unexplored ecological landscape within the human gut microbiome

The effects of supplied water quality on human health in an urban development with limited basic subsistence facilities

Domestic unavailability of water supply in South Africa often leads to improper use of supplied or other unsafe sources of water. The relationship between water quality, water availability, water accessibility, water use and incidence of diarrhoea due to these factors, was investigated in this study. The study was conducted in a large low socio-economic developing urban settlement. Reported diarrhoea cases were followed up to establish the water usage pattern of consumers in these particular households. Water was generally obtained from supply at public standpipes and stored in various forms of containers in households. Microbiological indicators were used to assess possible contamination of the water supply. Tests indicated limited instances of faecal and other forms of microbiological contamination in sections of the water-supply network. Indications were also found that the network in this area could intermittently be subjected to pollution from unknown sources although incidences were limited and not prolonged. Tests on the bulk water supply from the utility to the consumer water network indicated no faecal contamination in the bulk supply. In general the supply quality tested indicated no risk to consumers. However, the insanitary condition of containers as well as the manner of storing and handling of the containerised water led to contamination of water supplies. By implication, the system of water supply through public standpipe was conducive to conditions that could lead to contamination of stored water supply in households within the target consumer group