288 research outputs found

    The HST Survey of BL Lacertae Objects. II. Host Galaxies

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    We have used the HST WFPC2 camera to survey 132 BL Lac objects comprising seven complete radio-, X-ray-, and optically-selected samples. We obtained useful images for 110 targets spanning the redshift range 0 < z < 1.3. In two thirds of the BL Lac images, host galaxies are detected, including nearly all for z < 0.5 (58 of 63). The highest redshift host galaxy detected is in a BL Lac object at z=0.664. In 58 of the 72 resolved host galaxies, a de Vaucouleurs profile is significantly preferred, at >99% confidence, over a pure exponential disk; the two fits are comparable in the remaining 14 cases. These results limit the number of disk systems to at most 8% of BL Lacs (at 99% confidence), and are consistent with all BL~Lac host galaxies being ellipticals. The detected host galaxies are luminous ellipticals with a median absolute K-corrected magnitude of M_R= -23.7 +- 0.6 mag, at least one magnitude brighter than M* and comparable to brightest cluster galaxies. The galaxy morphologies are generally smooth and undisturbed, with small or negligible ellipticities (<0.2). There is no correlation between host galaxy and observed nuclear magnitude or estimated jet power corrected for beaming. If black hole mass is correlated linearly with bulge mass in general, this implies a large range in Eddington ratio. Present data strongly support the unification picture with FR I galaxies constituting the bulk of the parent population of BL Lac objects.Comment: Accepted for publication on ApJ. 38 pages, 8 figure

    Investigating the Interplay between Glucose Regulation, Neural Activity, and Motivation: A Novel Approach Utilizing Vibration Stimulation

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    This research explores the intricate relationship between glucose regulation, neural activity, and motivation in key brain regions, including the hypothalamus, basal ganglia, ventral tegmental area (VTA), and nucleus accumbens (NA). We aim to unravel the potential relationship of these factors on dopamine (DA) release and the broader implications for mental health, glucose regulation, well-being, and overall health. Our innovative approach involves using a chair that causes heterodyned whole-body vibration designed to stimulate DA release from the VTA and NA, areas associated with motivation and rewards

    Exploring Glucose Dysregulation in Migraine: Insights from Continuous Glucose Monitoring

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    Despite being associated with hypoglycemia for nearly a century, a definitive relationship between migraines and glucose dysregulation remains elusive. Accumulating evidence suggests that migraines are in part due to a metabolic mismatch between cerebral demand and available energy. Research analyzing plasma glucose levels and migraine activity may further elucidate this interface between metabolic dysregulation and migraine pathophysiology and may potentially open avenues for therapeutic interventions targeting holistic metabolism for migraine management

    Efficacy of indoor residual spraying with broflanilide (TENEBENAL), a novel meta-diamide insecticide, against pyrethroid-resistant anopheline vectors in northern Tanzania: An experimental hut trial.

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    Novel chemistry for vector control is urgently needed to counter insecticide resistance in mosquitoes. Here a new meta-diamide insecticide, broflanilide (TENEBENALTM), was evaluated in East African experimental huts in Moshi, northern Tanzania. Two consecutive experimental hut trials with broflanilide 50WP were conducted; the first evaluating the efficacy of three concentrations, 50 mg/m2, 100 mg/m2, and 200 mg/m2 using a prototype formulation, and the second trial evaluating an improved formulation. The IRS treatments were applied on both mud and concrete surfaces and efficacy was monitored over time. The mortality, blood-feeding inhibition and exiting behaviour of free-flying wild mosquitoes was compared between treatment arms. Additionally, cone assays with pyrethroid-susceptible and resistant mosquito strains were conducted in the huts to determine residual efficacy. The first trial showed a dosage-mortality response of the prototype formulation and 3-8 months of residual activity, with longer activity on concrete than mud. The second trial with an improved formulation showed prolonged residual efficacy of the 100 mg/m2 concentration to 5-6 months on mud, and mosquito mortality on the concrete surface ranged between 94-100% for the full duration of the trial. In both trials, results with free-flying, wild Anopheles arabiensis echoed the mortality trend shown in cone assays, with the highest dose inducing the highest mortality and the improved formulation showing increased mortality rates. No blood-feeding inhibition or insecticide-induced exiting effects were observed with broflanilide. Broflanilide 50WP was effective against both susceptible and pyrethroid-resistant mosquito strains, demonstrating an absence of cross resistance between broflanilide and pyrethroids. The improved formulation, which has now been branded VECTRONTM T500, resulted in a prolonged residual efficacy. These results indicate the potential of this insecticide as an addition to the arsenal of IRS products needed to maintain both control of malaria and resistance management of malaria-transmitting mosquitoes

    A non-inferiority and GLP-compliant study of broflanilide IRS (VECTRON™ T500), a novel meta-diamide insecticide against Anopheles arabiensis

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    Management of insecticide resistance in vector control requires development and evaluation of active ingredients (AIs) with new modes of action. VECTRON™ T500 is a wettable powder formulation used for Indoor Residual Spraying (IRS) containing 50% of broflanilide as an AI. This study evaluated the efficacy of VECTRON™ T500 sprayed on blocks of different substrates (concrete, mud and plywood) against pyrethroid susceptible and resistant Anopheles gambiae sensu stricto (s.s.) strains, and wild An. arabiensis. It also assessed the efficacy of VECTRON™ T500 in experimental huts plastered with mud and concrete against wild free-flying An. arabiensis; and non-inferiority to a World Health Organization listed indoor residual spraying product Actellic® 300CS in terms of mortality in Moshi, Tanzania.Monthly cone bioassays on blocks and in experimental huts (against pyrethroid susceptible and resistant An. gambiae s.s.) were conducted over a 12-month period after spraying of VECTRON™ T500 and Actellic® CS300. Collections of wild free-flying An. arabiensis were also done in the sprayed huts. The main outcome for cone bioassays was mortality while for the wild hut trial collections, it was mortality and blood feeding inhibition. Grouped logistic regressions with random effects were used to analyse all dichotomous outcome variables from wild collections.The results showed residual efficacy of VECTRON™ T500 of at least 80% mortality was longest on concrete, followed by plywood and then mud substrates for all mosquito strains. Furthermore, VECTRON™ T500 significantly increased the likelihood of mortality (OR:> 1.37, P<0.001) in wild collections of An. arabiensis compared to Actellic® 300CS. Blood feeding was not significantly different in the wild collection of An. arabiensis between VECTRON™ T500 and Actellic® 300CS arms.These results show that VECTRON™ T500 is efficacious against pyrethroid-resistant An. gambiae s.s. and non-inferior to Actellic® 300CS. Therefore, it should be an important addition to the current arsenal of insecticides used for insecticide resistance management and vector control

    FLT3 mutations in canine acute lymphocytic leukemia

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    <p>Abstract</p> <p>Background</p> <p>FMS-like tyrosine kinase 3 (FLT3) is a commonly mutated protein in a variety of human acute leukemias. Mutations leading to constitutively active FLT3, including internal tandem duplications of the juxtamembrane domain (ITD), result in continuous cellular proliferation, resistance to apoptotic cell death, and a poorer prognosis. A better understanding of the molecular consequences of FLT3 activation would allow improved therapeutic strategies in these patients. Canine lymphoproliferative diseases, including lymphoma and acute leukemias, share evolutionarily conserved chromosomal aberrations and exhibit conserved mutations within key oncogenes when compared to their human counterparts. A small percentage of canine acute lymphocytic leukemias (ALL) also exhibit <it>FLT3 </it>ITD mutations.</p> <p>Methods</p> <p>We molecularly characterized <it>FLT3 </it>mutations in two dogs and one cell line, by DNA sequencing, gene expression analysis via quantitative real-time PCR, and sensitivity to the FLT3 inhibitor lestaurtinib via <it>in vitro </it>proliferation assays. FLT 3 and downstream mediators of FLT3 activation were assessed by Western blotting.</p> <p>Results</p> <p>The canine B-cell leukemia cell line, GL-1, and neoplastic cells from 2/7 dogs diagnosed cytologically with ALL were found to have <it>FLT3 </it>ITD mutations and <it>FLT3 </it>mRNA up-regulation. Lestaurtinib, a small molecule FLT3 inhibitor, significantly inhibited the growth of GL-1 cells, while not affecting the growth of two other canine lymphoid cell lines without the <it>FLT3 </it>mutation. Finally, western blots were used to confirm the conserved downstream mediators of <it>FLT3 </it>activating mutations.</p> <p>Conclusions</p> <p>These results show that ALL and FLT3 biology is conserved between canine and human patients, supporting the notion that canine ALL, in conjunction with the GL-1 cell line, will be useful in the development of a relevant large animal model to aid in the study of human FLT3 mutant leukemias.</p

    Big Genomes Facilitate the Comparative Identification of Regulatory Elements

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    The identification of regulatory sequences in animal genomes remains a significant challenge. Comparative genomic methods that use patterns of evolutionary conservation to identify non-coding sequences with regulatory function have yielded many new vertebrate enhancers. However, these methods have not contributed significantly to the identification of regulatory sequences in sequenced invertebrate taxa. We demonstrate here that this differential success, which is often attributed to fundamental differences in the nature of vertebrate and invertebrate regulatory sequences, is instead primarily a product of the relatively small size of sequenced invertebrate genomes. We sequenced and compared loci involved in early embryonic patterning from four species of true fruit flies (family Tephritidae) that have genomes four to six times larger than those of Drosophila melanogaster. Unlike in Drosophila, where virtually all non-coding DNA is highly conserved, blocks of conserved non-coding sequence in tephritids are flanked by large stretches of poorly conserved sequence, similar to what is observed in vertebrate genomes. We tested the activities of nine conserved non-coding sequences flanking the even-skipped gene of the teprhitid Ceratis capitata in transgenic D. melanogaster embryos, six of which drove patterns that recapitulate those of known D. melanogaster enhancers. In contrast, none of the three non-conserved tephritid non-coding sequences that we tested drove expression in D. melanogaster embryos. Based on the landscape of non-coding conservation in tephritids, and our initial success in using conservation in tephritids to identify D. melanogaster regulatory sequences, we suggest that comparison of tephritid genomes may provide a systematic means to annotate the non-coding portion of the D. melanogaster genome. We also propose that large genomes be given more consideration in the selection of species for comparative genomics projects, to provide increased power to detect functional non-coding DNAs and to provide a less biased view of the evolution and function of animal genomes

    Seasonality of Plasmodium falciparum transmission: a systematic review

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    This article is fully open access and the published version is available free of charge from the jounal website.http://www.malariajournal.com/content/14/1/343Background Although Plasmodium falciparum transmission frequently exhibits seasonal patterns, the drivers of malaria seasonality are often unclear. Given the massive variation in the landscape upon which transmission acts, intra-annual fluctuations are likely influenced by different factors in different settings. Further, the presence of potentially substantial inter-annual variation can mask seasonal patterns; it may be that a location has “strongly seasonal” transmission and yet no single season ever matches the mean, or synoptic, curve. Accurate accounting of seasonality can inform efficient malaria control and treatment strategies. In spite of the demonstrable importance of accurately capturing the seasonality of malaria, data required to describe these patterns is not universally accessible and as such localized and regional efforts at quantifying malaria seasonality are disjointed and not easily generalized. Methods The purpose of this review was to audit the literature on seasonality of P. falciparum and quantitatively summarize the collective findings. Six search terms were selected to systematically compile a list of papers relevant to the seasonality of P. falciparum transmission, and a questionnaire was developed to catalogue the manuscripts. Results and discussion 152 manuscripts were identified as relating to the seasonality of malaria transmission, deaths due to malaria or the population dynamics of mosquito vectors of malaria. Among these, there were 126 statistical analyses and 31 mechanistic analyses (some manuscripts did both). Discussion Identified relationships between temporal patterns in malaria and climatological drivers of malaria varied greatly across the globe, with different drivers appearing important in different locations. Although commonly studied drivers of malaria such as temperature and rainfall were often found to significantly influence transmission, the lags between a weather event and a resulting change in malaria transmission also varied greatly by location. Conclusions The contradicting results of studies using similar data and modelling approaches from similar locations as well as the confounding nature of climatological covariates underlines the importance of a multi-faceted modelling approach that attempts to capture seasonal patterns at both small and large spatial scales. Keywords: Plasmodium falciparum ; Seasonality; Climatic driversAcknowledgements This work was supported by the Research and Policy for Infectious Disease Dynamics (RAPIDD) program of the Science and Technology Directory, Department of Homeland Security, and Fogarty International Center, National Institutes of Health. DLS is funded by a grant from the Bill & Melinda Gates Foundation (OPP1110495), which also supports RCR. PMA is grateful to the University of Utrecht for supporting him with The Belle van Zuylen Chair. PWG is a Career Development Fellow (K00669X) jointly funded by the UK Medical Research Council (MRC) and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreement and receives support from the Bill and Melinda Gates Foundation (OPP1068048, OPP1106023)
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