3,496 research outputs found

    A Large-Area RPC Detector for Muography

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    A muon telescope equipped with four Resistive Plate Chambers of 2 m2^{2} per plane was tested with the muon scattering tomography technique. The telescope was operated during several hours with high atomic number materials located at its center with two detector planes on each side. With an intrinsic efficiency above 98%, spatial resolution around 1 cm and detector planes spaced by 45 cm, it was possible to identify the presence of a 5 cm thick tungsten block in 10 minutes of acquisition. The results obtained after five hours of acquisition are also presented in this communication

    Advances Towards a Large-Area, Ultra-Low-Gas-Consumption RPC Detector

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    Large Resistive Plate Chamber systems have their roots in High Energy Physics experiments at the European Organization for Nuclear Research: ATLAS, CMS and ALICE, where hundreds of square meters of both trigger and timing RPCs have been deployed. These devices operate with complex gas systems, equipped with re-circulation and purification units, which require a fresh gas supply of the order of 6 cm3^{3}/min/m2^{2}, creating logistical, technical and financial problems. In this communication, we present a new concept in the construction of RPCs which allowed us to operate a detector at ultra-low gas flow regime. With this new approach, the glass stack is encapsulated in a tight plastic box made of polypropylene, which presents excellent water vapor blocking properties as well as a good protection against atmospheric gases.Comment: submission of the proceedings for the 15th PISA conference PM202

    Resistance Curves in the Tensile and Compressive Longitudinal Failure of Composites

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    This paper presents a new methodology to measure the crack resistance curves associated with fiber-dominated failure modes in polymer-matrix composites. These crack resistance curves not only characterize the fracture toughness of the material, but are also the basis for the identification of the parameters of the softening laws used in the analytical and numerical simulation of fracture in composite materials. The method proposed is based on the identification of the crack tip location by the use of Digital Image Correlation and the calculation of the J-integral directly from the test data using a simple expression derived for cross-ply composite laminates. It is shown that the results obtained using the proposed methodology yield crack resistance curves similar to those obtained using FEM-based methods in compact tension carbon-epoxy specimens. However, it is also shown that the Digital Image Correlation based technique can be used to extract crack resistance curves in compact compression tests for which FEM-based techniques are inadequate

    Uncovering the genetic basis for quality traits in the Mediterranean old wheat germplasm and phenotypic and genomic prediction assessment by cross-validation test

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    The release of new wheat varieties is based on two main characteristics, grain yield and quality, to meet the consumer’s demand. Identifying the genetic architecture for yield and key quality traits has wide attention for genetic improvement to meet the global requirement. In this sense, the use of landraces represents an impressive source of natural allelic variation. In this study, a genome-wide association analysis (GWAS) with PCA and kinship matrix was performed to detect QTLs in bread wheat for fifteen quality and agronomic traits using 170 diverse landraces from 24 Mediterranean countries in two years of field trials. A total of 53 QTL hotspots containing 165 significant marker-trait associations (MTAs) were located across the genome for quality and agronomical traits except for chromosome 2D. The major specific QTL hotspots for quality traits were QTL_3B.3 (13 MTAs with a mean PVE of 8.2%) and QTL_4A.3 (15 MTAs, mean PVE of 11.0%), and for yield-related traits were QTL_2B.1 (8 MTAs, mean PVE of 7.4%) and QTL_4B.2 (5 MTAs, mean PVE of 10.0%). A search for candidate genes (CG) identified 807 gene models within the QTL hotspots. Ten of these CGs were expressed specifically in grain supporting the role of identified QTLs in Landraces, associated to bread wheat quality traits and grain formation. A cross-validation approach within the collection was performed to calculate the accuracies of genomic prediction for quality and agronomical traits, ranging from -0.03 to 0.64 for quality and 0.46 to 0.65 for agronomic traits. In addition, five prediction equations using the phenotypic data were developed to predict bread loaf volume in landraces. The prediction ability varied from 0.67 to 0.82 depending on the complexity of the traits considered to predict loaf volume

    P53 and cancer-associated sialylated glygans are surrogate markers of cancerization of the bladder associated with \u3ci\u3eSchistosoma haematobium\u3c/i\u3e infection

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    Background Bladder cancer is a significant health problem in rural areas of Africa and the Middle East where Schistosoma haematobium is prevalent, supporting an association between malignant transformation and infection by this blood fluke. Nevertheless, the molecular mechanisms linking these events are poorly understood. Bladder cancers in infected populations are generally diagnosed at a late stage since there is a lack of non-invasive diagnostic tools, hence enforcing the need for early carcinogenesis markers. Methodology/Principal Findings Forty-three formalin-fixed paraffin-embedded bladder biopsies of S. haematobium-infected patients, consisting of bladder tumours, tumour adjacent mucosa and pre-malignant/malignant urothelial lesions, were screened for bladder cancer biomarkers. These included the oncoprotein p53, the tumour proliferation rate (Ki-67\u3e17%), cell-surface cancer-associated glycan sialyl-Tn (sTn) and sialyl-Lewisa/x (sLea/sLex), involved in immune escape and metastasis. Bladder tumours of non-S. haematobium etiology and normal urothelium were used as controls. S. haematobium-associated benign/pre-malignant lesions present alterations in p53 and sLex that were also found in bladder tumors. Similar results were observed in non-S. haematobium associated tumours, irrespectively of their histological nature, denoting some common molecular pathways. In addition, most benign/pre-malignant lesions also expressed sLea. However, proliferative phenotypes were more prevalent in lesions adjacent to bladder tumors while sLea was characteristic of sole benign/pre-malignant lesions, suggesting it may be a biomarker of early carcionogenesis associated with the parasite. A correlation was observed between the frequency of the biomarkers in the tumor and adjacent mucosa, with the exception of Ki-67. Most S. haematobium eggs embedded in the urothelium were also positive for sLea and sLex. Reinforcing the pathologic nature of the studied biomarkers, none was observed in the healthy urothelium. Conclusion/Significance This preliminary study suggests that p53 and sialylated glycans are surrogate biomarkers of bladder cancerization associated with S. haematobium, highlighting a missing link between infection and cancer development. Eggs of S. haematobium express sLea and sLex antigens in mimicry of human leukocytes glycosylation, which may play a role in the colonization and disease dissemination. These observations may help the early identification of infected patients at a higher risk of developing bladder cancer and guide the future development of non-invasive diagnostic tests

    Update on neurosurgical treatment for obsessive compulsive disorder

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    Responses to pharmacotherapy and psychotherapy in obsessive-compulsive disorder (OCD) range from 60 to 80% of cases. However, a subset of OCD patients do not respond to adequately conducted treatment trials, leading to severe psychosocial impairment. Stereotactic surgery can be indicated then as the last resource. Five surgical techniques are available, with the following rates of global post-operative improvement: anterior capsulotomy (38-100%); anterior cingulotomy (27-57%); subcaudate tractotomy (33-67%); limbic leucotomy (61-69%), and central lateral thalamotomy/anterior medial pallidotomy (62.5%). The first technique can be conducted as a standard neurosurgery, as radiosurgery or as deep brain stimulation. In the standard neurosurgery neural circuits are interrupted by radiofrequency. In radiosurgery, an actinic lesion is provoked without opening the brain. Deep brain stimulation consists on implanting electrodes which are activated by stimulators. Literature reports a relatively low prevalence of adverse events and complications. Neuropsychological and personality changes are rarely reported. However, there is a lack of randomized controlled trials to prove efficacy and adverse events/complication issues among these surgical procedures. Concluding, there is a recent development in the neurosurgeries for severe psychiatric disorders in the direction of making them more efficacious and safer. These surgeries, when correctly indicated, can profoundly alleviate the suffering of severe OCD patients.O transtorno obsessivo-compulsivo (TOC) responde aos tratamentos habituais (fármacos e psicoterapia) em cerca de 60 a 80% dos casos. Existe, assim, uma parcela de pacientes resistente aos tratamentos usuais, mesmo que adequadamente conduzidos, com grave prejuízo psicossocial. Nestas situações, a neurocirurgia pode ser indicada. Existem cinco técnicas cirúrgicas disponíveis, com as seguintes taxas de melhora global pós-operatória: capsulotomia anterior (38 a 100%); cingulotomia anterior (27 a 57%); tractotomia subcaudado (33 a 67%); leucotomia límbica (61 a 69%) e talamotomia central lateral com palidotomia anteromedial (62,5%). A capsulotomia anterior pode ser realizada através de diferentes técnicas: neurocirurgia padrão, radiocirurgia ou estimulação cerebral profunda. Na neurocirurgia padrão, circuitos neurais são interrompidos por radiofreqüência via trepanação no crânio. Na radiocirurgia, uma lesão actínica é induzida sem a necessidade de abertura do crânio. A estimulação cerebral profunda consiste na implantação de eletrodos ativados a partir de estimuladores. A literatura indica taxas relativamente baixas de eventos adversos e complicações, sendo raramente descritas alterações neuropsicológicas e de personalidade. Cumpre ressaltar, no entanto, a falta de ensaios clínicos randomizados que comprovem a eficácia e investiguem os eventos adversos ou complicações dos procedimentos cirúrgicos acima mencionados. Concluindo, há um recente aprimoramento das neurocirurgias dos transtornos psiquiátricos graves no sentido de torná-las cada vez mais eficazes e seguras. Estas cirurgias, quando adequadamente indicadas, podem trazer alívio substancial ao sofrimento de pacientes com TOC grave.Universidade de São Paulo Faculdade de Medicina Departamento de PsiquiatriaInstituto de Radiocirurgia NeurológicaUniversidade Federal de São Paulo (UNIFESP) Departamento de PsiquiatriaUNIFESP, Depto. de PsiquiatriaSciEL
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