294 research outputs found

    A Remote Laser System for Material Characterization at High Temperatures

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    For many years, new techniques have been developed to overcome the problems involved with the generation and detection of ultrasound in materials at high temperature [1,2]. A non-contacting technique is described using lasers to generate and detect ultrasound and which can be used to study the variation in acoustic velocity as a function of temperature. Results are presented for the change in longitudinal velocity (vℓ) with increasing temperature in five polycrystalline materials, namely Dural, aluminum, AISI-310 stainless steel, iron and graphite

    A Cytochrome b561 with Ferric Reductase Activity from the Parasitic Blood Fluke, Schistosoma japonicum

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    Parasites acquire their food from their hosts, either by feeding directly on tissues of the host, or by competing for ingested food. Adult schistosomes live within the vasculature of humans and rely on the blood cells and plasma they ingest and dissolved solutes they derive across their body surface, the tegument, for their nutrition. Schistosomes require host trace elements, notably iron, which is used as a co-factor in many biological reactions. Iron is especially important for schistosomes, for it has a significant role in egg formation and embryogenesis. In human tissues, iron predominates in the trivalent (ferric) form; however, it is the divalent (ferrous) form that is used as an essential co-factor for multiple biomolecules and enzymes. In order to be acquired from the host environment, the valency of iron must be modified to render it suitable for transport across the parasite membrane. This paper describes the molecular characterisation of a schistosome molecule that is crucial for bringing about this change in iron. Schistosoma japonicum Cytb561 is the first ferric reductase characterised in any parasitic helminth and emphasises the importance of iron, and other divalent cations, in these organisms

    Monoallelic variants resulting in substitutions of MAB21L1 Arg51 Cause Aniridia and microphthalmia

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    Classical aniridia is a congenital and progressive panocular disorder almost exclusively caused by heterozygous loss-of-function variants at the PAX6 locus. We report nine individuals from five families with severe aniridia and/or microphthalmia (with no detectable PAX6 mutation) with ultrarare monoallelic missense variants altering the Arg51 codon of MAB21L1. These mutations occurred de novo in 3/5 families, with the remaining families being compatible with autosomal dominant inheritance. Mice engineered to carry the p. Arg51Leu change showed a highly-penetrant optic disc anomaly in heterozygous animals with severe microphthalmia in homozygotes. Substitutions of the same codon (Arg51) in MAB21L2, a close homolog of MAB21L1, cause severe ocular and skeletal malformations in humans and mice. The predicted nucleotidyltransferase function of MAB21L1 could not be demonstrated using purified protein with a variety of nucleotide substrates and oligonucleotide activators. Induced expression of GFP-tagged wildtype and mutant MAB21L1 in human cells caused only modest transcriptional changes. Mass spectrometry of immunoprecipitated protein revealed that both mutant and wildtype MAB21L1 associate with transcription factors that are known regulators of PAX6 (MEIS1, MEIS2 and PBX1) and with poly(A) RNA binding proteins. Arg51 substitutions reduce the association of wild-type MAB21L1 with TBL1XR1, a component of the NCoR complex. We found limited evidence for mutation-specific interactions with MSI2/Musashi-2, an RNA-binding proteins with effects on many different developmental pathways. Given that biallelic loss-of-function variants in MAB21L1 result in a milder eye phenotype we suggest that Arg51-altering monoallelic variants most plausibly perturb eye development via a gain-of-function mechanism

    Possible mineral contributions to the diet and health of wild chimpanzees in three East African forests

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    For financial support, the authors acknowledge the Mohamed bin Zayed Species Conservation Fund grant numbers 0925272, 10251055, 11252562, 12254904, the Royal Zoological Society of Scotland, the Leverhulme Trust grant number ECF‐2013‐507, and the Boise Fund.We present new data on the ingestion of minerals from termite mound soil by East African chimpanzees (Pan troglodytes schweinfurthii) living in the Budongo Forest Reserve, Uganda, the Gombe National Park and the Mahale Mountains National Park, Tanzania. Termite mound soil is here shown to be a rich source of minerals, containing high concentrations of iron and aluminum. Termite mound soil is not, however, a source of sodium. The concentrations of iron and aluminum are the highest yet found in any of the mineral sources consumed. Levels of manganese and copper, though not so high as for iron and aluminum, are also higher than in other dietary sources. We focus on the contribution of termite mound soil to other known sources of mineral elements consumed by these apes, and compare the mineral content of termite soil with that of control forest soil, decaying wood, clay, and the normal plant‐based chimpanzee diet at Budongo. Samples obtained from Mahale Mountains National Park and Gombe National Park, both in Tanzania, show similar mineral distribution across sources. We suggest three distinct but related mechanisms by which minerals may come to be concentrated in the above‐mentioned sources, serving as potentially important sources of essential minerals in the chimpanzee diet.PostprintPeer reviewe

    Dihydrolipoic acid reduces cytochrome b561 proteins.

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    Cytochrome b561 (Cyt-b561) proteins constitute a family of trans-membrane proteins that are present in a wide variety of organisms. Two of their characteristic properties are the reducibility by ascorbate (ASC) and the presence of two distinct b-type hemes localized on two opposite sides of the membrane. Here we show that the tonoplast-localized and the putative tumor suppressor Cyt-b561 proteins can be reduced by other reductants than ASC and dithionite. A detailed spectral analysis of the ASC-dependent and dihydrolipoic acid (DHLA)-dependent reduction of these two Cyt-b561 proteins is also presented. Our results are discussed in relation to the known antioxidant capability of DHLA as well as its role in the regeneration of other antioxidant compounds of cells. These results allow us to speculate on new biological functions for the trans-membrane Cyt-b561 proteins

    Extent and patterns of community collaboration in local health departments: An exploratory survey

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    <p>Abstract</p> <p>Background</p> <p>Local public health departments (LHDs) in the United States have been encouraged to collaborate with various other community organizations and individuals. Current research suggests that many forms of active partnering are ongoing, and there are numerous examples of LHD collaboration with a specific organization for a specific purpose or program. However, no existing research has attempted to characterize collaboration, for the defined purpose of setting community health status priorities, between a defined population of local officials and a defined group of alternative partnering organizations. The specific aims of this study were to 1) determine the range of collaborative involvement exhibited by a study population of local public health officials, and, 2) characterize the patterns of the selection of organizations/individuals involved with LHDs in the process of setting community health status priorities.</p> <p>Methods</p> <p>Local health department officials in North Carolina (n = 53) responded to an exploratory survey about their levels of involvement with eight types of possible collaborator organizations and individuals. Descriptive statistics and the stochastic clustering technique of Self-Organizing Maps (SOM) were used to characterize their collaboration.</p> <p>Results</p> <p>Local health officials vary extensively in their level of collaboration with external collaborators. While the range of total involvement varies, the patterns of involvement for this specific function are relatively uniform. That is, regardless of the total level of involvement (low, medium or high), officials maintain similar hierarchical preference rankings with Community Advisory Boards and Local Boards of Health most involved and Experts and Elected Officials least involved.</p> <p>Conclusion</p> <p>The extent and patterns of collaboration among LHDs with other community stakeholders for a specific function can be described and ultimately related to outcome measures of LHD performance.</p

    Brain iron homeostasis, the choroid plexus, and localization of iron transport proteins

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    Maintenance of appropriate iron homeostasis in the brain is important, but the mechanisms involved in brain iron uptake are incompletely understood. Here, we have analyzed where messenger RNAs that encode iron transport proteins are expressed in the brain, using the Allen Brain atlas, and we conclude that several important iron transporters are highly expressed in the choroid plexus. Based on recent estimates of the surface area of the choroid plexus and on MRI imaging studies of manganese uptake in the brain, we propose that the choroid plexus may have a much greater role than has been previously appreciated in brain iron transport

    Adverse outcomes after colposcopy

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    Abstract Background Colposcopy is an essential part of the National Health Service Cervical Screening Programme (NHSCSP). It is used for both diagnosis and treatment of pre-cancerous cells of the cervix. Despite colposcopy being a commonly performed and relatively invasive procedure, very little research has explored the potential long-term impacts of colposcopic examination upon patient quality of life. The aim of this study is to investigate and quantify any potential reduction in women's quality of life following a colposcopy procedure. More specifically, the degree of female sexual dysfunction and the excess risk of adverse events in those undergoing colposcopy will be explored. If such risks are identified, these can be communicated to women before undergoing colposcopy. It will also assist in identifying whether there are particular sub-groups at greater risk and if so, this may lead to a re-evaluation of current recommendations concerning colposcopically directed treatments. Methods/design Cohort study using postal surveys to assess sexual function and quality of life in women who have attended for colposcopy (cases), compared with those who have not attended colposcopy (controls). The prevalence and excess risk of female sexual dysfunction will be determined. Logistic regression will identify the predictors of adverse outcomes. Discussion There are more than 400,000 colposcopy appointments each year in England, of which 134,000 are new referrals. There is some evidence that there may be long-term implications for women treated under colposcopy with respect to adverse obstetric outcomes, persisting anxiety, increased rates of sexual dysfunction and reduced quality of life. Reliably establishing whether such adverse outcomes exist and the excess risk of adverse events will facilitate informed decision-making and patient choice.</p
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