A study of damage accumulation in a knitted fabric reinforced composite.

The use of knitting technology with advanced fibres such as glass, carbon and aramid, to produce near-net-shape fabrics has in recent years received increasing interest from the composite materials community. Knitted fabrics have the potential of being used in engineering structures with complex shapes in conjunction with a suitable liquid moulding technique, such as Resin Transfer Moulding (RTM), due to their excellent drapeability and manufacturability. During previous studies in textile reinforced composites, an intimate relationship between the fabric architecture and the damage development has been demonstrated. In this work, the quasi-static tensile loading deformation behaviour and the relation between the fabric architecture and damage development have been studied for a weft knitted glass fabric. Tensile properties have been examined and the failure mechanisms have been identified experimentally by analysing the damage process in-situ with a camera and by studying fracture surfaces using scanning electron microscopy (SEM). The acoustic emission technique was used to support the microscopic analysis. The work has investigated the tensile properties and failure mechanisms of three knitted fabric reinforced composite laminates reinforced with a Milano weft knitted glass fabric. The three composites were (i) a single layer of fabric reinforcing epoxy resin, (ii) a single knitted fabric layer sandwiched between 0° glass fibre unidirectional plies (again with the glass reinforcing epoxy resin), and (iii) the same knitted glass fabric but this time used as the reinforcement in commercially produced high fibre volume fraction composites (using the RTM technique). The variation of mechanical properties with angle (from wale to course) has been measured for the single layer of the fabric reinforcing epoxy resin by orientating the wale direction of the fabric at different angles. Mechanical properties have been measured for each angular orientation and comparisons were made between them, especially with regard to the planes of final failure. The single layer composites failed as soon as the first damage was initiated. Hence, to investigate damage accumulation, a novel technique was employed to manufacture a sandwich laminate, which consisted in placing a single knitted fabric layer between 0° glass fibre unidirectional plies. The success of this method is that the accumulation of damage in the knitted architecture was allowed to be studied and some characteristics of crack initiation and crack propagation could be related to the fabric geometry and structure. Experiments on these model transparent materials have been complemented by tests on two types of commercial knitted fabric composite manufactured by the RTM process. Characterization of these materials under tensile loading has been carried out for monotonic and cyclic loading and the results have been compared with those found for the single layer and the sandwich model material. Various failure mechanisms such as cracking at loop cross-over points, resin matrix cracking, fibre bundle debonding and tensile fracture of fibre bundles in failed specimens were observed. The behaviour of the commercial RTM specimens has been discussed in the light of the results obtained from the model single layer and sandwich specimens

La punibilidad en la violencia psicológica en el distrito fiscal de Lima centro 2021

La presente investigación describe y explica un análisis de las falencias de los mecanismos legales y de punibilidad sobre violencia psicológica en Lima 2021, considera la participación de instituciones legales, de salud física y salud mental para su elaboración. La metodología empleada fue conforme al enfoque cualitativo, de tipo básica, diseño descriptivo de tipo fenomenológico, método investigación - acción, se ha empleado entrevistas presenciales confidenciales, semi estructuradas, participante y directa aplicando el método analítico-inductivo. Como resultados y discusión se identificó que los protocolos de pericia psicológica son parte de un grupo de falencias que se evidencian en los mecanismos de protección y abordaje legal, elementos de infraestructura; carencia de personal multifacultativo especializado; inversión pública no estratégica; falta de divulgación de alternativas de prevención e intervención sobre violencia psicológica; dificultad burocrática; negligencias multinivel. Además de descripción síntoma de la participación de violencia psicológica como víctimas, el conocimiento de un caso cercano sobre violencia, preocupación por las repercusiones del o los sucesos de violencia psicológica, el poco conocimiento sobre los Centros de Emergencia Mujer en Lima. Resulta indispensable el abordaje de esta problemática por la amplia gama de repercusiones en las víctimas

Oxidative Stress in the Local and Systemic Events of Apical Periodontitis

Oxidative stress is involved in the pathogenesis of a variety of inflammatory disorders. Apical periodontitis (AP) usually results in the formation of an osteolytic apical lesion (AL) caused by the immune response to endodontic infection. Reactive oxygen species (ROS) produced by phagocytic cells in response to bacterial challenge represent an important host defense mechanism, but disturbed redox balance results in tissue injury. This mini review focuses on the role of oxidative stress in the local and associated systemic events in chronic apical periodontitis. During endodontic infection, ligation of Toll-like receptors (TLRs) on phagocytes' surface triggers activation, phagocytosis, synthesis of ROS, activation of humoral and cellular responses, and production of inflammatory mediators, such as, cytokines and matrix metalloproteinases (MMPs). The increment in ROS perturbs the normal redox balance and shifts cells into a state of oxidative stress. ROS induce molecular damage and disturbed redox signaling, that result in the loss of bone homeostasis, increased pro-inflammatory mediators, and MMP overexpression and activation, leading to apical tissue breakdown. On the other hand, oxidative stress has been strongly involved in the pathogenesis of atherosclerosis, where a chronic inflammatory process develops in the arterial wall. Chronic AP is associated with an increased risk of cardiovascular diseases (CVD) and especially atherogenesis. The potential mechanisms linking these diseases are also discussed.Peer reviewe

Relación funcional de hecho en el delito de peculado y aplicación en el juzgado unipersonal anticorrupción de Huaraz, 2020 - 2021

Fluye de la investigación, lo relacionado a la relación funcional de hecho en el ilícito penal de peculado y aplicación en el juzgado unipersonal anticorrupción, en la ciudad de Huaraz, con lo que se sustenta el problema general ¿De qué manera se viene resolviendo los casos en los que existe relación funcional de hecho, en el Delito de Peculado y su aplicación en el Juzgado Unipersonal Especializado en Delitos de Corrupción de funcionarios de Huaraz, durante los años 2020-2021? Luego de ello, se formuló el objetivo general: Establecer la manera cómo se viene resolviendo los casos en los que existe relación funcional de hecho, en el Delito de Peculado y su aplicación en el Juzgado Unipersonal Especializado en Delitos de Corrupción de funcionarios de Huaraz, durante los años 2020-2021. Del mismo modo, se tienen los siguientes objetivos específicos: 1. Determinar el grado de responsabilidad, del ejercicio de jure, de la función pública; 2. Verificar el grado de responsabilidad, del ejercicio de facto, de la función pública; 3. Analizar aquellos casos en los que exista relación funcional de hecho, en el delito de peculado. La investigación es de tipo básico, y tiene un enfoque cualitativo

Carcinoma de células claras de ovario, a propósito de un caso

Introduction: The histological classification of surgery tumors by the World Health Organization (WHO) is based on histogenetic principles, and it divides surgery tumors according to their derivation of epithelial cells, germ cells and mesenchymal cells (stroma and sex cord). Objective: to describe the clinical- epidemiological characteristics of clear cell ovarian carcinoma. Methodology: we made a review of the bibliography on the subject and presented the results. Results: Clear cell carcinoma (CCC) of the ovary has been reported to have a worse prognosis than all other neoplasms in this group. Taking this into account, this presentation of a case attended in our institution has been carried out, with an effective treatment, valid for the survival of the patient and a good quality of life. Conclusions: it is an epithelial ovarian tumor frequently resistant to conventional chemotherapy.Introducción: La clasificación histológica de los tumores ováricos por la Organización Mundial de la Salud (OMS) se basa en principios histogenéticos, y esta divide los tumores ováricos de acuerdo a su derivación de células epiteliales, células germinales y mesenquimales (el estroma y el cordón sexual). Objetivo: describir las características clínico- epidemiológicas del carcinoma de células claras de ovario. Metodología: hicimos una revisión de la bibliografía sobre el tema y presentamos los resultados. Resultados: Se ha notificado que el carcinoma de células claras (CCC) del ovario tiene un pronóstico peor que el resto de las neoplasias de este grupo. Teniendo en cuenta esto, se ha llevado a cabo esta presentación de un caso atendido en nuestra institución, con un tratamiento efectivo, válido por la sobrevida de la paciente y una buena calidad de vida.  Conclusiones: se trata de un tumor de ovario epitelial frecuentemente resistente a la quimioterapia convenciona

Manufacture of Partially Biodegradable Composite Materials Based on PLA-Tires Powder: Process and Characterization

This research work focuses on the processability and mechanical characterization of blends of polylactic acid (PLA) and tire (elastomeric part). Wasted tires used as filler in the PLA matrix were reduced by two different processes (thermal shock and pyrolysis) in order to acquire the solid residuals in powder to be characterized and compared. Elastomeric solids obtained from scraped tires were used as filler in the PLA matrix and mixed in a Brabender 60 cc mixer at different concentrations ranging from 0% to 60% of filler volume fraction. The blend was laminated, and then samples were obtained in order to undertake mechanical properties at tension and Izod impact tests. A fully detailed analysis on the solid powders by Differential Scanning Calorimeter (DSC), thermogravimetric analysis (TGA), infrared analysis (IR), and scanning electron microscopy analysis (SEM) identified them as a rich source of carbon. Blends were characterized thermally and mechanically showing a direct effect due to the tire nature (thermoset rubber) and concentration. Fracture mechanisms were also identified

AmericasNLI: Machine translation and natural language inference systems for Indigenous languages of the Americas

Little attention has been paid to the development of human language technology for truly low-resource languages—i.e., languages with limited amounts of digitally available text data, such as Indigenous languages. However, it has been shown that pretrained multilingual models are able to perform crosslingual transfer in a zero-shot setting even for low-resource languages which are unseen during pretraining. Yet, prior work evaluating performance on unseen languages has largely been limited to shallow token-level tasks. It remains unclear if zero-shot learning of deeper semantic tasks is possible for unseen languages. To explore this question, we present AmericasNLI, a natural language inference dataset covering 10 Indigenous languages of the Americas. We conduct experiments with pretrained models, exploring zero-shot learning in combination with model adaptation. Furthermore, as AmericasNLI is a multiway parallel dataset, we use it to benchmark the performance of different machine translation models for those languages. Finally, using a standard transformer model, we explore translation-based approaches for natural language inference. We find that the zero-shot performance of pretrained models without adaptation is poor for all languages in AmericasNLI, but model adaptation via continued pretraining results in improvements. All machine translation models are rather weak, but, surprisingly, translation-based approaches to natural language inference outperform all other models on that task