7,649 research outputs found

    Lysenko and the screwworm fly—when politics interferes with science and public health

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    In the One Health scenario, a deep understanding of the dynamics potentially threatening the development and implementation of useful pest and vector management tools is of key importance. The New World screwworm fly, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), is characterized by a wide host range. It acts as an important agent of myiasis in humans and warm-blooded animals in the Neotropics, and has been eliminated from a wide region through genetic methods. Of note, Serebrovsky had already proposed in 1940 the principles of autocidal control by the translocation of segments between two chromosomes, but his work was negated by Lysenko, based on the negation of Mendelian genetics. This entomological case study emphasizes the danger of politics interfering with science, a still contemporary hot issue. The negation of global warming or current pandemics are further examples of this noxious influence

    Estratégias para reduzir a mortalidade embrionária em bovinos: II. Protocolo para reduzir a mortalidade embrionária em vacas de leite e em receptoras de embrião.

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    A mortalidade embrionária precoce é a maior causa de perdas reprodutivas em bovinos e ela relaciona-se, principalmente com os distúrbios do reconhecimento materno da prenhez originados em disfunções do corpo lúteo ovariano. Recentemente, foi desenvolvido na Embrapa Pecuária Sudeste, um protocolo hormonal que melhora a função luteínica e permite aumentar a oportunidade para um reconhecimento materno da prenhez bem sucedido. O protocolo baseia-se na administração de hormônios reprodutivos (GnRH e hCG) em ocasiões estratégicas após a ovulação. Foram realizados dois experimentos, um com vacas leiteiras e outro com receptoras de embrião, para testar e validar o uso desse protocolo. Após a aplicação do tratamento houve aumento nas taxas de prenhez. Os resultados detalhados do uso dessa prática estão descritos no presente Boletim de Pesquisa e Desenvolvimento. O protocolo testado traduz-se numa prática pecuária de controle das funções ovariana e uterina que otimiza a eficiência reprodutiva de vacas leiteiras e de receptoras de embrião.bitstream/item/43513/1/Boletim27.pd

    Beta-tricalcium phosphate ceramic triggers fast and robust bone formation by human mesenchymal stem cells

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    Due to their osteoconductive and inductive properties, a variety of calcium phosphate (CaP) scaffolds are commonly used in orthopaedics as graft material to heal bone defects. In this study, we have used two CaP scaffolds with different hydroxyapatite (HA) and \u3b2-tricalcium phosphate (\u3b2-TCP) ratios (MBCP\uae; 60/40 and MBCP+\uae; 20/80) to investigate their intrinsic capacity to favour human bone marrow stem cells (hBMSCs) osteogenic differentiation capacity. We report that MBCP+\uae showed in in vitro culture model a higher rate of calcium ion release in comparison with MBCP\uae. In two defined coculture systems, the hBMSC seeded onto MBCP+\uae presented an increased amount of VEGF secretion, resulting in an enhanced endothelial cell proliferation and capillary formation compared with hBMSC seeded onto MBCP\uae. When both ceramics combined with hBMSC were implanted in a nude mouse model, we observed a faster osteogenic differentiation and enhancement mature bone deposition sustained by the presence of a vast host vasculature within the MBCP+\uae ceramics. Bone formation was observed in samples highly positive to the activation of calcium sensing receptor protein (CaSr) on the surface of seeded hBMSC that also shown higher BMP-2 protein expression. With these data we provide valuable insights in the possible mechanisms of ossification and angiogenesis by hBMSC that we believe to be primed by calcium ions released from CaP scaffolds. Evidences could lead to an optimization of ceramic scaffolds to prime bone repair

    Learning algorithms estimate pose and detect motor anomalies in flies exposed to minimal doses of a toxicant

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    Pesticide exposure, even at low doses, can have detrimental effects on ecosystems. This study aimed at validating the use of machine learning for recognizing motor anomalies, produced by minimal insecticide exposure on a model insect species. The Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), was exposed to food contaminated with low concentrations of Carlina acaulis essential oil (EO). A deep learning approach enabled fly pose estimation on video recordings in a custom-built arena. Five machine learning algorithms were trained on handcrafted features, extracted from the predicted pose, to distinguish treated individuals. Random Forest and K-Nearest Neighbor algorithms best performed, with an area under the receiver operating characteristic (ROC) curve of 0.75 and 0.73, respectively. Both algorithms achieved an accuracy of 0.71. Results show the machine learning potential for detecting sublethal effects arising from insecticide exposure on fly motor behavior, which could also affect other organisms and environmental health

    The proangiogenic capacity of polymorphonuclear neutrophils delineated by microarray technique and by measurement of neovascularization in wounded skin of CD18-deficient mice

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    Growing evidence supports the concept that polymorphonuclear neutrophils (PMN) are critically involved in inflammation-mediated angiogenesis which is important for wound healing and repair. We employed an oligonucleotide microarray technique to gain further insight into the molecular mechanisms underlying the proangiogenic potential of human PMN. In addition to 18 known angiogenesis-relevant genes, we detected the expression of 10 novel genes, namely midkine, erb-B2, ets-1, transforming growth factor receptor-beta(2) and -beta(3), thrombospondin, tissue inhibitor of metalloproteinase 2, ephrin A2, ephrin B2 and restin in human PMN freshly isolated from the circulation. Gene expression was confi rmed by the RT-PCR technique. In vivo evidence for the role of PMN in neovascularization was provided by studying neovascularization in a skin model of wound healing using CD18-deficient mice which lack PMN infi ltration to sites of lesion. In CD18-deficient animals, neo- vascularization was found to be signifi cantly compromised when compared with wild- type control animals which showed profound neovascularization within the granulation tissue during the wound healing process. Thus, PMN infiltration seems to facilitate inflammation mediated angiogenesis which may be a consequence of the broad spectrum of proangiogenic factors expressed by these cells. Copyright (c) 2006 S. Karger AG, Basel

    Training and Onboarding initiatives in High Energy Physics experiments

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    In this paper we document the current analysis software training and onboarding activities in several High Energy Physics (HEP) experiments: ATLAS, CMS, LHCb, Belle II and DUNE. Fast and efficient onboarding of new collaboration members is increasingly important for HEP experiments as analyses and the related software become ever more complex with growing datasets. A meeting series was held by the HEP Software Foundation (HSF) in 2022 for experiments to showcase their initiatives. Here we document and analyse these in an attempt to determine a set of key considerations for future experiments

    Effects of a commercially available branched-chain amino acid-alanine-carbohydrate-based sports supplement on perceived exertion and performance in high intensity endurance cycling tests

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    Background:Sports nutritional supplements containing branched-chain amino acids (BCAA) have been widelyreported to improve psychological and biological aspects connected to central fatigue and performance inendurance exercise, although the topic is still open to debate. The aim of the present study was to determinewhether the intake of a commercially available BCAA-based supplement, taken according to the manufacturer’srecommendations, could affect the rating of perceived exertion (RPE) and performance indexes at the beginning(1d) and end of a 9-week (9w) scheduled high intensity interval training program, with an experimental approachintegrating the determination of psychometric, performance, metabolic and blood biochemical parameters.Methods:This was a randomized double-blind placebo-controlled study. Thirty-two untrained, healthy young adults(20 males and 12 female) were enrolled. A high-intensity endurance cycling (HIEC) test was used to induce fatigue inthe participants: HIEC consisted in ten 90 s sprints interspersed by ten 3 min recovery phases and followed by a finalstep time to exhaustion was used. In parallel with RPE, haematological values (creatine kinase, alanine, BCAA,tryptophan, ammonia and glucose levels), and performance indexes (maximal oxygen consumption - VO2max,powerassociated with lactate thresholds - WLT1,WLT2and time to exhaustion - TTE) were assessed. All subject took thesupplement (13.2 g of carbohydrates; 3.2 g of BCAA and 1.6 g of L-alanine per dose) or placebo before each test andtraining session. Dietary habits and training load were monitored during the entire training period.Results:The administration of the supplement (SU) at 1d reduced RPE by 9% during the recovery phase, as comparedto the placebo (PL); at 9w the RPE scores were reduced by 13 and 21% during the sprint and recovery phase,respectively; at 9w, prolonged supplement intake also improved TTE and TRIMP. SU intake invariably promoted a rapidincrease (within 1 h) of BCAA serum blood levels and prevented the post-HIEC tryptophan: BCAA ratio increase foundin the PL group, at both 1d and 9w. There was no difference in dietary habits between groups and those habits didnot change over time; no difference in glycemia was found between SU and PL. VO2max,WLT1and WLT2valuesimproved over time, but were unaffected by supplement intake. Conclusions:On the whole, these results suggest that i) the intake of the BCAA-based commercially availablesupplement used in this study reduces RPE as a likely consequence of an improvement in the serum tryptophan: BCAAratio; ii) over time, reduced RPE allows subjects to sustain higher workloads, leading to increased TRIMP and TTE

    In Vitro and in Vivo Effectiveness of Carvacrol, Thymol and Linalool against Leishmania infantum

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    Background: One of the most important causative agents of visceral leishmaniasis (VL) is Leishmania infantum, which is mainly spread by Phlebotomus and Lutzomyia sandflies in the Old and New World, respectively. Novel and effective drugs to manage this neglected vector-borne disease are urgently required. In this study, we evaluated the toxicity of carvacrol, thymol and linalool, three common essential oil constituents, on amastigotes and promastigotes of L. infantum. Methods: in vitro experiments were performed by 24 h MTT assay. Carvacrol, thymol and linalool at concentrations ranging from 1.3 to 10 µg/mL were tested on promastigotes of L. infantum. For in vivo test, two groups of hamsters (Mesocricetus auratus) received 100 mg/kg of body weight/day of carvacrol and thymol as intraperitoneal injection on day 7 post-infection, followed by a 48 h later injection. The third group was treated with the glucantime as standard drug (500 mg/kg) and the last group (control) just received normal saline. On the 16th day, the number of parasites and histopathological changes in liver and spleen were investigated. Results: 24 h MTT assay showed promising antileishmanial activity of thymol and carvacrol, with IC50 values of 7.2 (48 µM) and 9.8 µg/mL (65 µM), respectively. Linalool at all concentrations did not affect L. infantum promastigote viability. In vivo toxicity data of carvacrol and thymol showed that the former at 100 mg/kg was the safest and most effective treatment with little side effects on the liver. Conclusions: Overall, thymol and carvacrol are highly promising candidates for the development of effective and safe drugs in the fight against VL
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