Polycyclic aromatic hydrocarbons in residential dust: sources of variability.

BackgroundThere is interest in using residential dust to estimate human exposure to environmental contaminants.ObjectivesWe aimed to characterize the sources of variability for polycyclic aromatic hydrocarbons (PAHs) in residential dust and provide guidance for investigators who plan to use residential dust to assess exposure to PAHs.MethodsWe collected repeat dust samples from 293 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001 through 2007 and during 2010) using household vacuum cleaners, and measured 12 PAHs using gas chromatography-mass spectrometry. We used a random- and a mixed-effects model for each PAH to apportion observed variance into four components and to identify sources of variability.ResultsMedian concentrations for individual PAHs ranged from 10 to 190 ng/g of dust. For each PAH, total variance was apportioned into regional variability (1-9%), intraregional between-household variability (24-48%), within-household variability over time (41-57%), and within-sample analytical variability (2-33%). Regional differences in PAH dust levels were associated with estimated ambient air concentrations of PAH. Intraregional differences between households were associated with the residential construction date and the smoking habits of residents. For some PAHs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Within-household differences between sampling rounds were largest when the interval between dust sample collections was at least 6 years in duration.ConclusionsOur findings indicate that it may be feasible to use residential dust for retrospective assessment of PAH exposures in studies of health effects

Pseudoangiomatous Stromal Hyperplasia: A Case Report

Pseudoangiomatous stromal hyperplasia (PASH) is a rare benign proliferating breast condition. It was first reported in 1986 when Vuitch, Rosen, and Erlandson described nine cases of benign well-circumscribed, breast masses that simulated vascular lesions consisting of mammary stromal proliferations (Vuitch et al. (1986)). Since then there have been few reported cases of PASH in the literature (Taira et al. (2005)). We describe a large PASH, mimicking inflammatory carcinoma in a young lady that was excised with excellent cosmetic results

Superior infectivity for mosquito vectors contributes to competitive displacement among strains of dengue virus

<p>Abstract</p> <p>Background</p> <p>Competitive displacement of a weakly virulent pathogen strain by a more virulent strain is one route to disease emergence. However the mechanisms by which pathogens compete for access to hosts are poorly understood. Among vector-borne pathogens, variation in the ability to infect vectors may effect displacement. The current study focused on competitive displacement in dengue virus serotype 3 (DENV3), a mosquito-borne pathogen of humans. In Sri Lanka in the 1980's, a native DENV3 strain associated with relatively mild dengue disease was displaced by an invasive DENV3 strain associated with the most severe disease manifestations, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), resulting in an outbreak of DHF/DSS. Here we tested the hypothesis that differences between the invasive and native strain in their infectivity for <it>Aedes aegypti </it>mosquitoes, the primary vector of DENV, contributed to the competitive success of the invasive strain</p> <p>Results</p> <p>To be transmitted by a mosquito, DENV must infect and replicate in the midgut, disseminate into the hemocoel, infect the salivary glands, and be released into the saliva. The ability of the native and invasive DENV3 strains to complete the first three steps of this process in <it>Aedes aegypti </it>mosquitoes was measured <it>in vivo</it>. The invasive strain infected a similar proportion of mosquitoes as the native strain but replicated to significantly higher titers in the midgut and disseminated with significantly greater efficiency than the native strain. In contrast, the native and invasive strain showed no significant difference in replication in cultured mosquito, monkey or human cells.</p> <p>Conclusion</p> <p>The invasive DENV3 strain infects and disseminates in <it>Ae. aegypti </it>more efficiently than the displaced native DENV3 strain, suggesting that the invasive strain is transmitted more efficiently. Replication in cultured cells did not adequately characterize the known phenotypic differences between native and invasive DENV3 strains. Infection dynamics within the vector may have a significant impact on the spread and replacement of dengue virus lineages.</p

Environmental interventions to reduce fear of crime: systematic review of effectiveness

Background: Fear of crime is associated with negative health and wellbeing outcomes, and may mediate some impacts of the built environment on public health. A range of environmental interventions have been hypothesized to reduce the fear of crime. Methods: This review aimed to synthesize the literature on the effectiveness of interventions in the built environment to reduce the fear of crime. Systematic review methodology, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance, was used. Studies of environmental interventions which reported a fear of crime outcome and used any prospective evaluation design (randomized controlled trial (RCT), trial or uncontrolled before-and-after study) were included. Eighteen databases were searched. The Hamilton tool was used to assess quality. A narrative synthesis of findings was undertaken. Results: A total of 47 studies were included, 22 controlled and 25 uncontrolled, with total sample sizes ranging from n = 52 to approximately n = 23,000. Thirty-six studies were conducted in the UK, ten studies in the USA and one study in the Netherlands. The quality of the evidence overall is low. There are some indications that home security improvements and non-crime-related environmental improvements may be effective for some fear of crime outcomes. There is little evidence that the following reduce fear of crime: street lighting improvements, closed-circuit television (CCTV), multi-component environmental crime prevention programs or regeneration programs. Conclusions: There is some evidence for the effectiveness of specific environmental interventions in reducing some indicators of fear of crime, but more attention to the context and possible confounders is needed in future evaluations of complex social interventions such as these

Non-chlorine detergent formulations as an alternative for unpasteurised milk removal from stainless steel surfaces

Hygiene is a major concern in the dairy industry, and detergents based on hypochlorite have commonly been utilised for cleaning-in-place (CIP) regimes. However, due to concerns about chlorate residues entering the milk processing chain, new detergent alternatives that are free of chlorate sources are required. Two new formulations were developed based on ethylenediaminetetraacetic acid (EDTA) and wetting agents. Stainless steel surfaces were fouled with milk and cleaned once or 10 times using water, a caustic-EDTA product, a sodium hypochlorite product, an acid, or new cleaning formulations (Product A and Product B). The results demonstrated that the use of acid did not result in successful cleaning. The two new products performed well, with Product B performing equivalently during cleaning compared with the established hypochlorite or caustic-EDTA products. Product A exhibited better cleanliness than the other detergents tested. When allergen removal was considered, residual material was found to be retained on the surfaces, regardless of the cleaning type used. This study suggests that the new product formulations may be used to replace hypochlorite-based detergents to increase the hygienic status of a surface

Patients After the Fontan Insights From Computational Fluid Dynamics

Reprints: Information about reprints can be found online a

A trade-off in replication in mosquito versus mammalian systems conferred by a point mutation in the NS4B protein of dengue virus type 4

AbstractAn acceptable live-attenuated dengue virus vaccine candidate should have low potential for transmission by mosquitoes. We have identified and characterized a mutation in dengue virus type 4 (DEN4) that decreases the ability of the virus to infect mosquitoes. A panel of 1248 mutagenized virus clones generated previously by chemical mutagenesis was screened for decreased replication in mosquito C6/36 cells but efficient replication in simian Vero cells. One virus met these criteria and contained a single coding mutation: a C-to-U mutation at nucleotide 7129 resulting in a Pro-to-Leu change in amino acid 101 of the nonstructural 4B gene (NS4B P101L). This mutation results in decreased replication in C6/36 cells relative to wild-type DEN4, decreased infectivity for mosquitoes, enhanced replication in Vero and human HuH-7 cells, and enhanced replication in SCID mice implanted with HuH-7 cells (SCID-HuH-7 mice). A recombinant DEN4 virus (rDEN4) bearing this mutation exhibited the same set of phenotypes. Addition of the NS4B P101L mutation to rDEN4 bearing a 30 nucleotide deletion (Δ30) decreased the ability of the double-mutant virus to infect mosquitoes but increased its ability to replicate in SCID-HuH-7 mice. Although the NS4B P101L mutation decreases infectivity of DEN4 for mosquitoes, its ability to enhance replication in SCID-HuH-7 mice suggests that it might not be advantageous to include this specific mutation in an rDEN4 vaccine. The opposing effects of the NS4B P101L mutation in mosquito and vertebrate systems suggest that the NS4B protein is involved in maintaining the balance between efficient replication in the mosquito vector and the human host

How equitable is vocational rehabilitation in Sweden? A review of evidence on the implementation of a national policy framework

Purpose. Under the national framework law in Sweden, all eligible people should have equal chances of receiving vocational rehabilitation. We aimed to review the evidence on (1) whether access to vocational rehabilitation is equitable in practice and (2) whether the outcomes vary for different groups in the population. Method. Systematic review of studies in Sweden that reported diagnostic or socio-demographic characteristics of people offered or taking up rehabilitation programmes and outcomes of such programmes for different diagnostic and socio-demographic groups. Searches of 11 relevant electronic databases, 15 organisational websites, citation searching and contact with experts in the field, for the period 1990–2009. Results. A total of 11 studies were included in the final review, six of which addressed review question (1) and seven addressed review question (2). All the six observational studies of access reported biased selection into vocational rehabilitation: greater likelihood for men, younger people, those with longer-term sick leave, those with lower income, employed rather than unemployed people and those with musculoskeletal and mental disorders or alcohol abuse. Having had a rehabilitation investigation also increased the likelihood of receiving vocational rehabilitation. Differential outcome of rehabilitation was reported in seven studies: outcomes were better for men, younger people, employed individuals, those with shorter sick leave and those with higher income. Selection into vocational rehabilitation was perceived as important for successful outcomes, but success also depended on the state of the local labour market. Conclusions. There is evidence of socio-demographic differences in access to and outcomes of vocational rehabilitation in Sweden, even though the national framework law is meant to apply to everyone. Few studies have deliberately measured differential access or outcomes, and there is a need for this kind of equity analysis of population-wide policies. Studies evaluating the effects of vocational rehabilitation must consider selection into the programmes for adequate interpretation of impact results

The effect of surface properties on bacterial retention: a study utilising stainless steel and TiN/25.65at.%Ag substrata

The requirement for antimicrobial surfaces to control microorganisms for use in the food industries is increasing. A TiN/25.65at.%Ag coating and a stainless steel (304 2R) surface were characterised for roughness parameters, chemistry and physicochemistry (PC). Microbiological analysis was performed to determine the antimicrobial efficacy and retention of Staphylococcus aureus and Escherichia coli on the surfaces. Zone of inhibition assays were successful against only E. coli on the TiN/25.65at.%Ag coating. A bacterial respiratory assay demonstrated that the TiN/25.65at.%Ag coating was antimicrobial against both bacteria. Retention assays demonstrated that the physicochemistry of the bacteria and surfaces influenced bacterial retention. Multifractal analysis of the retained bacteria demonstrated that the surface properties affected the spread and clustering, but not the density of the bacteria. This work suggests that surface properties influenced specific species: surface interactions and therefore surfaces need to be tailored to specific requirements depending on the environment and microorganisms to be targeted. This work may aid in the production of coatings or surfaces that may provide more hygienic conditions

Effects of Cationic and Anionic Surfaces on the Perpendicular and Lateral Forces and Binding of Aspergillus niger Conidia

The binding of conidia to surfaces is a prerequisite for biofouling by fungal species. In this study, Aspergillus niger subtypes 1957 and 1988 were used which produced differently shaped conidia (round or spikey respectively). Test surfaces were characterised for their surface topography, wettability, and hardness. Conidial assays included perpendicular and lateral force measurements, as well as attachment, adhesion and retention assays. Anionic surfaces were less rough (Ra 2.4 nm), less wettable (54°) and harder (0.72 GPa) than cationic surfaces (Ra 5.4 nm, 36° and 0.5 GPa, respectively). Perpendicular and lateral force assays demonstrated that both types of conidia adhered with more force to the anionic surfaces and were influenced by surface wettability. Following the binding assays, fewer A. niger 1957 and A. niger 1988 conidia bound to the anionic surface. However, surface wettability affected the density and dispersion of the conidia on the coatings, whilst clustering was affected by their spore shapes. This work demonstrated that anionic surfaces were more repulsive to A. niger 1998 spores than cationic surfaces were, but once attached, the conidia bound more firmly to the anionic surfaces. This work informs on the importance of understanding how conidia become tightly bound to surfaces, which can be used to prevent biofouling