1,232 research outputs found

    Análise Comparativa In Vitro do Desgaste Promovido nos Terços Cervical e Medio dos Canais Radiculares Mésio-vestibulares de Molares Superiores pelo Sistema K3 e Limas Manuais Associadas a Brocas Gates Glidden

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    Root canal instrumentation is one of the most important part in endodontic practice. The purpose of this study was to make an analysis of dental thickness in mesial and distal surfaces of maxillary mesiobuccal molar root canals after instrumentation with Gates Glidden drills and stainless steel hand files versus nickel titanium K3 rotary files. Twenty roots were cross-sectioned at 1mm apically to the canal root canal orifice and 1mm coronally to the curvature. Ten root canals had a coronal flaring with Gates Glidden 1 and Gates Glidden 2 and instrumentation with stainless steel hand files. Another ten roots, were shaped using K3 rotary files. The dental thickness was measured before and after the instrumentation in a stereomicroscope. The results were analysed by Student t Test (pA instrumentação dos canais radiculares é uma das etapas mais importantes da terapia endodôntica. Este estudo realizou uma análise comparativa do desgaste promovido nas paredes mesial e distal do canal mésio-vestibular de molares superiores, terços cervical e médio, pela associação das brocas Gates Glidden (Dentsply Maillefer, Ballaigues, Switzerland)) com limas manuais e pelo sistema automatizado K3 (SybronEndo, CA, USA). A amostra consistiu em vinte raízes que foram, primeiramente, incluídas em uma modificação da mufla proposta por Bramante et al (1987). Após a inclusão, as mesmas foram seccionadas transversalmente em duas superfícies de observação, 1 mm além do orifício de entrada do canal e 1mm aquém do início dacurvatura. O preparo cervical de dez raízes foi realizado com as brocas Gates Glidden números 1 e 2, sendo a instrumentação concluída com limas manuais. As outras dez raízes tiveram seus condutos preparados pelo sistema K3. As espessuras de dentina das paredes analisadas foram medidas antes e após os preparos através do uso de um microscópio metalográfico (Union), com ocular graduada, no aumento de 50x. Os resultados demonstraram valores médios de desgaste nas paredes analisadas maiores nos preparos realizados com a associação das brocas Gates Glidden e limas manuais. Somente na parede distal 1mm da entrada do canal o sistema K3 apresentou o valor médio pouco superior. Os dados foram submetidos ao Teste t de Student para amostras não pareadas, não apresentando diferenças estatisticamente significantes. Concluiu-se através deste trabalho, que as técnicas de preparo apresentam um desempenho semelhante quanto ao desgaste radicular dos terços cervical e médio

    Pirógenos en material de venoclisis como posible causa de reacciones febriles agudas en niños (Pediatría, hospital San Juan de dios santa ana

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    Las soluciones de venoclisis son elementos fundamentales de muchos tratamientos médico hospitalarios, estimándose que el 25 % de la drogas en los hospitales son administradas en forma de inyección. las ventajas aportadas por la administración de drogas por vía parenteral son bien reconocidas por todos los que practican la medicina, incluyéndose entre otras, la posibilidad de lograr concenticiones séricas efectivas con la rapidez necesaria. El término parenteral se aplica a preparaciones administradas por inyección a través de una o más capas del tejido de la piel. Casi desde que se comenzó a utilizar la vía de administración parenteral aparecieron reportes de reacciones febriles después de la aparición. Estas reacciones fueron estudiadas y atribuidas a diversas fuentes, pero no fue sino hasta 1923 que Florence Seibert conoció corno causantes de estas reacciones, a partículas proveniente de bacterias, que existían previamente en el agua utilizada como solvente. Estas reacciones indeseables fueron identificadas posteriormente corno reacciones pirogénicas y se manifiestan por fiebre dolor y malestar general En una discusión sobre la bioquímica de pirógenos, Good declaro que la entidad primariamente responsable de la respuesta pirogénica en los mamíferos es un lipopolisacárido. No obstante que los distintos investigadores admiten para los pirógenos una naturaleza lipopolisacárida común ( aunque en algunos casos también existen combinaciones de polisacáridos y de polipétidos ) es notable la diferencia que se encuentra en la respuesta febril a los pirógenos de distintos gérmenes, considerándose como más potente los de los gérmenes gran negativo

    Ciencias de la Biología y Agronomía

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    Este volumen I contiene 17 capítulos arbitrados que se ocupan de estos asuntos en Tópicos Selectos de Ciencias de la Biología y Agronomía, elegidos de entre las contribuciones, reunimos algunos investigadores y estudiantes. Se presenta un Estudio Comparativo de los Recursos Hidrológico-Forestales de la Microcuenca de la Laguna de Epatlan, Pue. (1993 a 2014); la Situación Actual de la Mancha de Asfalto en Maíz (Zea mays L.) en los Municipios de Jiquipilas y Ocozocoautla, Chiapas, México; las poblaciones sobresalientes de maíz de la raza Zapalote Chico, en la Región Istmeña de Oaxaca; Se indica el índice de área foliar de cultivo de Chile Poblano mediante dos métodos en condiciones protegidas; Esquivel, Urzúa y Ramírez exploran el efecto de la biofertilización con Azospirillum en el crecimiento y producción de Jitomate; esbozan su artículo sobre la determinación del nivel de Heterosis en híbridos de Maíz para la Comarca Lagunera; una investigación sobre la estabilización de semilla de Solanum lycopersicum durante el almacenamiento y estimulación de la germinación; acotan sobre el CTAB como una nueva opción para la detección de Huanglongbing en cítricos, plantean su evaluación sobre el aluminio y cómo afecta la vida de florero de Heliconia psittacorum; indican sobre el impacto del H-564C, como un híbrido de maíz con alta calidad de proteina para el trópico húmedo de México; presetan su investigación sobre la producción de Piña Cayena Lisa y MD2 (Ananas comosus L.) en condiciones de Loma Bonita, en Oaxaca; acotan sobre el efecto de coberteras como control biológico por conservación contra áfidos en Nogal Pecanero; esbozan sobre la caracterización de cuatro genotipos de Frijol Negro en Martínez de la Torre, Veracruz, México; presentan una caracterización hidroecológica de la microcuenca de Arroyo Prieto, Yuriría, Gto., y alternativas para su restauración ambiental; presentan su investigación sobre el efecto del hongo Beauveria bassiana sobre solubilización de fosfatos y la disponibilidad de fósforo en el suelo; plantean su investigación sobre la Germinación y regeneración in vitro de Epidendrum falcatum LINDL; esbozan su artículo sobre genotipos de frijol negro y su tolerancia a sequía terminal en Veracruz, México

    Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

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    Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

    Outcomes of elective liver surgery worldwide: a global, prospective, multicenter, cross-sectional study

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    Background: The outcomes of liver surgery worldwide remain unknown. The true population-based outcomes are likely different to those vastly reported that reflect the activity of highly specialized academic centers. The aim of this study was to measure the true worldwide practice of liver surgery and associated outcomes by recruiting from centers across the globe. The geographic distribution of liver surgery activity and complexity was also evaluated to further understand variations in outcomes. Methods: LiverGroup.org was an international, prospective, multicenter, cross-sectional study following the Global Surgery Collaborative Snapshot Research approach with a 3-month prospective, consecutive patient enrollment within January–December 2019. Each patient was followed up for 90 days postoperatively. All patients undergoing liver surgery at their respective centers were eligible for study inclusion. Basic demographics, patient and operation characteristics were collected. Morbidity was recorded according to the Clavien–Dindo Classification of Surgical Complications. Country-based and hospital-based data were collected, including the Human Development Index (HDI). (NCT03768141). Results: A total of 2159 patients were included from six continents. Surgery was performed for cancer in 1785 (83%) patients. Of all patients, 912 (42%) experienced a postoperative complication of any severity, while the major complication rate was 16% (341/2159). The overall 90-day mortality rate after liver surgery was 3.8% (82/2,159). The overall failure to rescue rate was 11% (82/ 722) ranging from 5 to 35% among the higher and lower HDI groups, respectively. Conclusions: This is the first to our knowledge global surgery study specifically designed and conducted for specialized liver surgery. The authors identified failure to rescue as a significant potentially modifiable factor for mortality after liver surgery, mostly related to lower Human Development Index countries. Members of the LiverGroup.org network could now work together to develop quality improvement collaboratives

    Event reconstruction for KM3NeT/ORCA using convolutional neural networks

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    The KM3NeT research infrastructure is currently under construction at two locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino detector off the French coast will instrument several megatons of seawater with photosensors. Its main objective is the determination of the neutrino mass ordering. This work aims at demonstrating the general applicability of deep convolutional neural networks to neutrino telescopes, using simulated datasets for the KM3NeT/ORCA detector as an example. To this end, the networks are employed to achieve reconstruction and classification tasks that constitute an alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT Letter of Intent. They are used to infer event reconstruction estimates for the energy, the direction, and the interaction point of incident neutrinos. The spatial distribution of Cherenkov light generated by charged particles induced in neutrino interactions is classified as shower- or track-like, and the main background processes associated with the detection of atmospheric neutrinos are recognized. Performance comparisons to machine-learning classification and maximum-likelihood reconstruction algorithms previously developed for KM3NeT/ORCA are provided. It is shown that this application of deep convolutional neural networks to simulated datasets for a large-volume neutrino telescope yields competitive reconstruction results and performance improvements with respect to classical approaches

    Event reconstruction for KM3NeT/ORCA using convolutional neural networks

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    The KM3NeT research infrastructure is currently under construction at two locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino de tector off the French coast will instrument several megatons of seawater with photosensors. Its main objective is the determination of the neutrino mass ordering. This work aims at demonstrating the general applicability of deep convolutional neural networks to neutrino telescopes, using simulated datasets for the KM3NeT/ORCA detector as an example. To this end, the networks are employed to achieve reconstruction and classification tasks that constitute an alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT Letter of Intent. They are used to infer event reconstruction estimates for the energy, the direction, and the interaction point of incident neutrinos. The spatial distribution of Cherenkov light generated by charged particles induced in neutrino interactions is classified as shower-or track-like, and the main background processes associated with the detection of atmospheric neutrinos are recognized. Performance comparisons to machine-learning classification and maximum-likelihood reconstruction algorithms previously developed for KM3NeT/ORCA are provided. It is shown that this application of deep convolutional neural networks to simulated datasets for a large-volume neutrino telescope yields competitive reconstruction results and performance improvements with respect to classical approaches

    Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

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    Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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