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Zero-export photovoltaic systems are an option to transition to Smart Grids. They decarbonize the sector without affecting third parties. This paper proposes the analysis of a zero-export PVS with a green hydrogen generation and storage system. This configuration is feasible to apply by any self-generation entity; it allows the user to increase their resilience and independence from the electrical network. The technical issue is simplified because the grid supplies no power. The main challenge is finding an economic balance between the savings in electricity billing, proportional to the local electricity rate, and the complete system's investment, operation, and maintenance expenses. This manuscript presents the effects of the power sizing on the efficacy of economic savings in billing (ηSaving) and the effects of the cost reduction on the levelized cost of energy (LCOE) and a discounted payback period (DPP) based on net present value. In addition, this study established an analytical relationship between LCOE and DPP. The designed methodology proposes to size and selects systems to use and store green hydrogen from the zero-export photovoltaic system. The input data in the case study are obtained experimentally from the Autonomous University of the State of Quintana Roo, located on Mexico's southern border. The maximum power of the load is LPmax = 500 kW, and the average power is LPmean = 250 kW; the tariff of the electricity network operator has hourly conditions for a medium voltage demand. A suggested semi-empirical equation allows for determining the efficiency of the fuel cell and electrolyzer as a function of the local operating conditions and the nominal power of the components. The analytical strategy, the energy balance equations, and the identity functions that delimit the operating conditions are detailed to be generalized to other case studies. The results are obtained by a computer code programmed in C++ language. According to our boundary conditions, results show no significant savings generated by the installation of the hydrogen system when the zero-export photovoltaic system Power ≤ LPmax and DPP ≤ 20 years is possible only with LCOE ≤ 0.1 $/kWh. Specifically for the Mexico University case study, zero-export photovoltaic system cost must be less than 310 $/kW, fuel cell cost less than 395 $/kW, and electrolyzer cost less than 460 $/kW.

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Introducción: La reanimación neonatal demanda dispositivos para apoyo respiratorio que no siempre se encuentran en áreas rurales. Se requieren dispositivos innovadores y el prototipado rápido permite generarlos usando diseños e impresoras tridimensionales (3D). Objetivo: Evaluar el desempeño no clínico y la aceptabilidad por el personal de salud de un dispositivo respiratorio neonatal producido mediante prototipado rápido. Métodos: Estudio observacional, descriptivo, de prueba de concepto desarrollado en dos etapas. Etapa 1: Fabricación del dispositivo con prototipado rápido en impresoras y escáneres tridimensionales (3D). Etapa 2: Demostración del dispositivo durante programas de capacitación en reanimación neonatal para personal de salud en tres regiones del Perú (Tarapoto, Huánuco y Ayacucho). En ambas etapas se evaluó el desempeño del dispositivo conectado a un analizador de flujo de gases. Se administró una encuesta a los trabajadores de salud de Tarapoto y Ayacucho para conocer su aceptabilidad. Resultados: El prototipo desarrollado tiene forma de T con dos fuelles laterales que al presionarse con una sola mano, proyectan aire por el centro hacia un adaptador facial. El uso del prototipo en laboratorio generó un flujo de aire promedio de 4,8 Lt/min (DE ± 1,7) y una presión promedio de 5,9 cm H2O (DE ± 1,4). Este dispositivo fue considerado como "de uso muy simple" en una encuesta de aceptabilidad donde participaron 39 enfermeras y 11 médicos en zonas alejadas de la capital del Perú. Conclusiones: El prototipo evaluado fue aceptado por el personal y tuvo un desempeño capaz de generar un estímulo de la respiración espontánea al nacer.

Introduction: Neonatal resuscitation demands equipment for respiratory support not always available in rural areas. Innovative devices are required, and rapid prototyping allows to generate them using three-dimensional (3D) designs and printers. Objective: To evaluate the non-clinical performance and the acceptability by health personnel of a neonatal respiratory device produced by rapid prototyping. Methods: Observational study, descriptive, of proof of concept developed in two steps. Step 1: Manufacture of the device with rapid prototyping in three-dimensional (3D) scanners and printers. Step 2: Demonstration of the invention during training programs in neonatal resuscitation for health personnel in three regions of Peru (Tarapoto, Huánuco and Ayacucho). In both steps, we evaluated the performance of the device connected to a gas flow analyser. A survey was administered to the health workers of Tarapoto and Ayacucho to know their acceptability. Results: The developed prototype is T-shaped with two side bellows that, when pressed with one hand, project air through the centre towards a facial adapter. The use of the prototype in the laboratory generated an average air flow of 4.8 Lt /min (SD ± 1.7) and an average pressure of 5.9 cm H2O (SD ± 1.4). This device was considered to be "very simple to use" in an acceptability survey involving 39 nurses and 11 doctors in remote areas of the capital of Peru. Conclusions: The evaluated prototype is acceptable by the staff and has a performance capable of generating spontaneous breathing at birth.

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BACKGROUND: Total hip arthroplasty is the most successful orthopedic procedure and the frequency of use of revision components has grown exponentially. The increased number of revisions results from the longer life expectancy of the population and the greater frequency of the hip arthroplasty indication among young patients. The purpose of this study is to evaluate the functional results of patients subjected to revision of the acetabular component using reinforcement rings. MATERIAL AND METHODS: The study included patients with a diagnosis of septic or aseptic prosthetic loosening and sequelae of acetabular fractures between January 2007 and November 2009 in whom a reinforcement ring was used. The WOMAC scale was used for the functional evaluation. RESULTS: According to the WOMAC scale, the patient functionality results showed a mean preoperative score of 41.89 and a mean postoperative score of 74.26, which represented an improvement of 33.11 points in the median of patients subjected to the surgical intervention, with a statistically significant difference (p = 0.036). DISCUSSION: This study shows an improvement in the functionality of the patients subjected to surgery with a reinforcement ring, as, first and foremost, a statistically significant difference was seen between the preoperative and postoperative values and, secondly, there are papers published in the literature showing that a difference of more than 12 points between the preoperative and postoperative scores in the WOMAC scale indicates a significant clinical improvement of patients. CONCLUSION: Patients subjected to acetabular revision with a reinforcement ring together with cemented polyethylene have an improved quality of life after the surgical intervention.

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El objetivo de este estudio es analizar la correlación clínica-radiológica en los diagnósticos establecidos, en las unidades médicas de primero y segundo nivel, del Instituto Mexicano del Seguro Social en Lázaro Cardenas, Mich. Se trata de un estudio de correlación, diagnóstica y radiológica con base en el expediente clínico, desde el punto de vista de un segundo observador, bajo la concordancia de un criterio de verdad aceptado. Se analizaron 407 expedientes. La correlación diagnóstica se estableció con un porcentaje de concordancia de 89 por ciento con un coeficiente de Kappa de .78, la pertinencia del apoyo radiológico solicitado se estableció con un porcentaje de concordancia de 85 por ciento, y un coeficiente de Kappa de .71. Los resultados de la correlación del estudio radiológico se presento con un porcentaje de 71.49 con un coeficiente de 45. Los dos primeros valores presentan una fuerza sustancial, consideramos que éstos se pueden incrementar, mediante la consistencia de la información y recopilación clínica en forma adecuada. El tercer valor presenta una fuerza moderada, que se puede modificar mediante la implementación y difusión de cuadros de eficacia de los procedimientos de apoyo diagnóstico de radiología

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La frecuencia del desarrollo de malignidad en un teratoma quístico maduro de ovario es de 1-2 por ciento. La mayoría de los casos informados ocurren en mujeres posmenopaúsicas. En este artículo se comunican dos casos de carcinoma epidermoide originado en un teratoma quístico maduro de ovario, uno de los cuales se presentó en una mujer joven. En el otro caso podemos sustentar que el origen del componente carcinomatoso se encuentra en el epitelio columnar y en la epidermis de los tejidos propios del teratoma

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