270 research outputs found

    Application of electron multiplying CCD technology in space instrumentation

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    Electron multiplying CCD (EMCCD) technology has found important initial applications in low light surveillance and photon starved scientific instrumentation. This paper discusses the attributes of the EMCCD which make it useful for certain space instruments, particularly those which are photon starved, and explores likely risks from the radiation expected in such instruments

    Recurrent Modification of a Conserved Cis-Regulatory Element Underlies Fruit Fly Pigmentation Diversity

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    The development of morphological traits occurs through the collective action of networks of genes connected at the level of gene expression. As any node in a network may be a target of evolutionary change, the recurrent targeting of the same node would indicate that the path of evolution is biased for the relevant trait and network. Although examples of parallel evolution have implicated recurrent modification of the same gene and cis-regulatory element (CRE), little is known about the mutational and molecular paths of parallel CRE evolution. In Drosophila melanogaster fruit flies, the Bric-à-brac (Bab) transcription factors control the development of a suite of sexually dimorphic traits on the posterior abdomen. Female-specific Bab expression is regulated by the dimorphic element, a CRE that possesses direct inputs from body plan (ABD-B) and sex-determination (DSX) transcription factors. Here, we find that the recurrent evolutionary modification of this CRE underlies both intraspecific and interspecific variation in female pigmentation in the melanogaster species group. By reconstructing the sequence and regulatory activity of the ancestral Drosophila melanogaster dimorphic element, we demonstrate that a handful of mutations were sufficient to create independent CRE alleles with differing activities. Moreover, intraspecific and interspecific dimorphic element evolution proceeded with little to no alterations to the known body plan and sex-determination regulatory linkages. Collectively, our findings represent an example where the paths of evolution appear biased to a specific CRE, and drastic changes in function were accompanied by deep conservation of key regulatory linkages. © 2013 Rogers et al

    Fracking in the UK press: threat dynamics in an unfolding debate

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    Shale gas is a novel source of fossil fuel which is extracted by induced hydraulic fracturing, or “fracking”. This article examines the socio-political dimension of fracking as manifested in the UK press at three key temporal points in the debate on the practice. Three newspaper corpora were analysed qualitatively using Thematic Analysis and Social Representations Theory. Three overarching themes are discussed: “April–May 2011: From Optimism to Scepticism”; “November 2011: (De-)Constructing and Re-Constructing Risk and Danger”; “April 2012: Consolidating Social Representations of Fracking”. In this article, we examine the emergence of and inter-relations between competing social representations, discuss the dynamics of threat positioning and show how threat can be re-construed in order to serve particular socio-political ends in the debate on fracking

    Independent position correction on tumor and lymph nodes; consequences for bladder cancer irradiation with two combined IMRT plans

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    Abstract Background The application of lipiodol injections as markers around bladder tumors combined with the use of CBCT for image guidance enables daily on-line position correction based on the position of the bladder tumor. However, this might introduce the risk of underdosing the pelvic lymph nodes. In this study several correction strategies were compared. Methods For this study set-up errors and tumor displacements for ten complete treatments were generated; both were based on the data of 10 bladder cancer patients. Besides, two IMRT plans were made for 20 patients, one for the elective field and a boost plan for the tumor. For each patient 10 complete treatments were simulated. For each treatment the dose was calculated without position correction (option 1), correction on bony anatomy (option 2), on tumor only (option 3) and separately on bone for the elective field (option 4). For each method we analyzed the D99% for the tumor, bladder and lymph nodes and the V95% for the small intestines, rectum, healthy part of the bladder and femoral heads. Results CTV coverage was significantly lower with options 1 and 2. With option 3 the tumor coverage was not significantly different from the treatment plan. The ΔD99% (D99%, option n - D99%, treatment plan) for option 4 was small, but significant. For the lymph nodes the results from option 1 differed not significantly from the treatment plan. The median ΔD99% of the other options were small, but significant. ΔD99% for PTVbladder was small for options 1, 2 and 4, but decreased up to -8.5 Gy when option 3 was applied. Option 4 is the only method where the difference with the treatment plan never exceeds 2 Gy. The V95% for the rectum, femoral heads and small intestines was small in the treatment plan and this remained so after applying the correction options, indicating that no additional hot spots occurred. Conclusions Applying independent position correction on bone for the elective field and on tumor for the boost separately gives on average the best target coverage, without introducing additional hot spots in the healthy tissue.</p

    Role of traditional healers in the management of severe malaria among children below five years of age: the case of Kilosa and Handeni Districts, Tanzania

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    BACKGROUND: The current malaria control strategy of WHO centres on early diagnosis and prompt treatment using effective drugs. Children with severe malaria are often brought late to health facilities and traditional health practitioners are said to be the main cause of treatment delay. In the context of the Rectal Artesunate Project in Tanzania, the role of traditional healers in the management of severe malaria in children was studied. METHODOLOGY: A community cross-sectional study was conducted in Kilosa and Handeni Districts, involving four villages selected on the basis of existing statistics on the number of traditional health practitioners involved in the management of severe malaria. A total of 41 traditional health practitioners were selected using the snowballing technique, whereby in-depth interviews were used to collect information. Eight Focus Group Discussions (FGDs) involving traditional health practitioners, caregivers and community leaders were carried out in each district. RESULTS: Home management of fever involving sponging or washing with warm water at the household level, was widely practiced by caregivers. One important finding was that traditional health practitioners and mothers were not linking the local illness termed degedege, a prominent feature in severe malaria, to biomedically-defined malaria. The majority of mothers (75%) considered degedege to be caused by evil spirits. The healing process was therefore organized in stages and failure to abide to the procedure could lead to relapse of degedege, which was believed to be caused by evil spirits. Treatment seeking was, therefore, a complex process and mothers would consult traditional health practitioners and modern health care providers, back and forth. Referrals to health facilities increased during the Rectal Artesunate Project, whereby project staff facilitated the process after traditional medical care with the provision of suppositories. This finding is challenging the common view that traditional healers are an important factor of delay for malaria treatment, they actually play a pivotal role by giving "bio-medically accepted first aid" which leads to reduction in body temperature hence increasing chances of survival for the child. Increasing the collaboration between traditional healers and modern health care providers was shown to improve the management of severe malaria in the studied areas. INTERPRETATION AND CONCLUSION: Traditional health care is not necessarily a significant impediment or a delaying factor in the treatment of severe malaria. There is a need to foster training on the management of severe cases, periodically involving both traditional health practitioners and health workers to identify modalities of better collaboration

    Phase II study of helical tomotherapy in the multidisciplinary treatment of oligometastatic colorectal cancer

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    <p>Abstract</p> <p>Background</p> <p>Complete metastasectomy provides a real chance for long-term survival in patients with oligometastatic colorectal cancer (CRC). For inoperable patients, we evaluated in this study intensity-modulated and image-guided radiotherapy (IMRT-IGRT) by helical tomotherapy.</p> <p>Methods</p> <p>Twenty-four CRC patients with ≤ 5 metastases were enrolled, receiving a dose of 50 Gy in fractions of 5 Gy. No limitations concerning dimension or localization of the metastases were imposed. Whole body PET-CT was performed at baseline and 3 months after the initiation of RT to evaluate the metabolic response rate according to PET Response Criteria in Solid Tumors (PERCIST) version 1.0.</p> <p>Results</p> <p>A total of 53 metastases were treated. Seventeen patients (71%) received previously ≥ 1 line of chemotherapy for metastatic disease, displaying residual (n = 7) or progressive (n = 10) metabolic active oligometastatic disease at time of inclusion. Most common sites were the lung, liver and lymphnodes. One patient (4%) experienced grade 3 dysphagia. Twenty-two patients were evaluated by post-treatment PET-CT. Twelve patients achieved a complete (n = 6) or partial (n = 6) metabolic response, resulting in an overall metabolic response rate of 55%. At a median follow-up of 10 months, 7 patients (29%) are in remission, of which 5 received previous chemotherapy with residual oligometastatic disease at time of inclusion. The actuarial 1-year local control, progression-free survival, and overall survival were 54%, 14% and 78%.</p> <p>Conclusions</p> <p>Helical tomotherapy delivering 10 fractions of 5 Gy resulted in a metabolic response rate of 55%, and appeared to be attractive as consolidation of inoperable oligometastatic disease after effective chemotherapy.</p> <p>Trial registration</p> <p>Eudract 2008-008300-40; <a href="http://www.clinicaltrials.gov/ct2/show/NCT00807313">NCT00807313</a></p

    Population transcriptomics of Drosophila melanogaster females

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    <p>Abstract</p> <p>Background</p> <p>Variation at the level of gene expression is abundant in natural populations and is thought to contribute to the adaptive divergence of populations and species. Gene expression also differs considerably between males and females. Here we report a microarray analysis of gene expression variation among females of 16 <it>Drosophila </it><it>melanogaster </it>strains derived from natural populations, including eight strains from the putative ancestral range in sub-Saharan Africa and eight strains from Europe. Gene expression variation among males of the same strains was reported previously.</p> <p>Results</p> <p>We detected relatively low levels of expression polymorphism within populations, but much higher expression divergence between populations. A total of 569 genes showed a significant expression difference between the African and European populations at a false discovery rate of 5%. Genes with significant over-expression in Europe included the insecticide resistance gene <it>Cyp6g1</it>, as well as genes involved in proteolysis and olfaction. Genes with functions in carbohydrate metabolism and vision were significantly over-expressed in the African population. There was little overlap between genes expressed differently between populations in females and males.</p> <p>Conclusions</p> <p>Our results suggest that adaptive changes in gene expression have accompanied the out-of-Africa migration of <it>D. melanogaster</it>. Comparison of female and male expression data indicates that the vast majority of genes differing in expression between populations do so in only one sex and suggests that most regulatory adaptation has been sex-specific.</p

    The prevalence of pelvic organ prolapse symptoms and signs and their relation with bladder and bowel disorders in a general female population

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    Contains fulltext : 81191.pdf (publisher's version ) (Closed access)INTRODUCTION AND HYPOTHESIS: In selected populations, pelvic organ prolapse (POP) was associated with bladder/bowel symptoms, but data on the general female population are lacking. Our aim was to obtain normative data on the prevalence of POP and pelvic floor dysfunction (PFD) symptoms and signs and to identify associations. METHODS: Validated questionnaires on POP and PFD (urogenital distress inventory, (UDI) and defaecation distress inventory (DDI)) were sent to a general population of 2,979 women (aged 45-85 years). Data were analysed using the Kruskal-Wallis test, chi square test and Spearman's rank correlation coefficient. RESULTS: Response rate was 62.7%. Associations between POP stage and parity (0.002) and vaginal bulging (<0.001) are significant. Anatomical locations of POP and PFD symptoms correlated significantly with incontinence of flatus, feeling anal prolapse, manual evacuation of stool, vaginal bulging, constipation and pain during faecal urge (p < or = 0.005). CONCLUSIONS: Strategies should be developed to alleviate obstructive bowel disorders associated with POP

    Antenatal HIV testing in rural eastern Uganda in 2003: incomplete rollout of the prevention of mother-to-child transmission of HIV programme?

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    BACKGROUND: Uganda began to implement the prevention of mother-to-child transmission (PMTCT) of HIV programme in 2000, and by the end of 2003 it had expanded to cover 38 of the 56 districts including Mbale District. However, reports from Mbale Hospital showed that less than 10% of pregnant women accepted antenatal HIV testing. We therefore conducted a study to determine the proportion of pregnant women who tested for HIV and the gaps and barriers in PMTCT implementation. METHODS: The study was a cross sectional household survey of women aged 18 years or more, with children aged one year or less, who resided in Mbale Town or in the surrounding Bungokho County. We also conducted in-depth interviews with six health workers in Mbale Hospital. RESULTS: In 2003, we interviewed 457 women with a median age of 24 years. The prevalence of antenatal HIV testing was 10 percent. The barriers to antenatal HIV testing were unavailability of voluntary counselling and testing services (44%), lack of HIV counselling (42%) and perceived lack of benefits for HIV infected women and their infants. Primipara (OR 2.6, 95% CI 1.2–5.8), urban dwellers (OR 2.7, 95% CI 1.3–5.8), women having been counselled on HIV (OR 6.2, 95% CI 2.9–13.2), and women with husbands being their primary confidant (OR 2.3, 95% CI 1.0–5.5) were independently associated with HIV testing. CONCLUSION: The major barriers to PMTCT implementation were unavailability of PMTCT services, particularly in rural clinics, and poor antenatal counselling and HIV testing services. We recommend that the focus of the prevention of mother-to-child transmission of HIV programme should shift to the district and sub-district levels, strengthen community mobilization, improve the quality of antenatal voluntary counselling and HIV testing services, use professional and peer counsellors to augment HIV counselling, and ensure follow-up care and support for HIV positive women and their infants

    Automatic Robust Neurite Detection and Morphological Analysis of Neuronal Cell Cultures in High-content Screening

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    Cell-based high content screening (HCS) is becoming an important and increasingly favored approach in therapeutic drug discovery and functional genomics. In HCS, changes in cellular morphology and biomarker distributions provide an information-rich profile of cellular responses to experimental treatments such as small molecules or gene knockdown probes. One obstacle that currently exists with such cell-based assays is the availability of image processing algorithms that are capable of reliably and automatically analyzing large HCS image sets. HCS images of primary neuronal cell cultures are particularly challenging to analyze due to complex cellular morphology. Here we present a robust method for quantifying and statistically analyzing the morphology of neuronal cells in HCS images. The major advantages of our method over existing software lie in its capability to correct non-uniform illumination using the contrast-limited adaptive histogram equalization method; segment neuromeres using Gabor-wavelet texture analysis; and detect faint neurites by a novel phase-based neurite extraction algorithm that is invariant to changes in illumination and contrast and can accurately localize neurites. Our method was successfully applied to analyze a large HCS image set generated in a morphology screen for polyglutaminemediated neuronal toxicity using primary neuronal cell cultures derived from embryos of a Drosophila Huntington’s Disease (HD) model.National Institutes of Health (U.S.) (Grant
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