Efficient multivariable submarine depth-control system design

An efficient solution for the multivariable submarine control design at low-depth conditions under the influence of wave disturbances is presented. The analysis and control design process is carried out under the framework of individual channel analysis and design (ICAD), which is based on the multivariable structure function (MSF). Classical frequency-domain control techniques based on Bode and Nyquist plots are used. Robustness is stated in terms of gain and phase margins. The closed-loop system includes low-order diagonal controllers facilitating its implementation, assessment, and tuning. ICAD discloses new physical insights of the submarine dynamical behaviour. Previous designs based on diagonal controllers consider the input–output channels defined by pairing the bow hydroplane angle with the depth and the stern hydroplane angle with the pitch angle. The alternative input–output pairing leads to unstable closed-loop systems. This phenomenon is associated with hydroplane reverse control. Here it is shown that MSF-based diagonal controllers can be applied effectively for both sets of channel configurations. Emphasis is placed on satisfying design specifications aiming at maintaining the depth low. The solution presented is more feasible and clearer to apply in practice than those so far reported in the literature

Red nucleus and rubrospinal tract disorganization in the absence of Pou4f1

The red nucleus (RN) is a neuronal population that plays an important role in forelimb motor control and locomotion. Histologically it is subdivided into two subpopulations, the parvocellular RN (pRN) located in the diencephalon and the magnocellular RN (mRN) in the mesencephalon. The RN integrates signals from motor cortex and cerebellum and projects to spinal cord interneurons and motor neurons through the rubrospinal tract (RST). Pou4f1 is a transcription factor highly expressed in this nucleus that has been related to its specification. Here we profoundly analyzed consequences of Pou4f1 loss-of-function in development, maturation and axonal projection of the RN. Surprisingly, RN neurons are specified and maintained in the mutant, no cell death was detected. Nevertheless, the nucleus appeared disorganized with a strong delay in radial migration and with a wider neuronal distribution; the neurons did not form a compacted population as they do in controls, Robo1 and Slit2 were miss-expressed. Cplx1 and Npas1, expressed in the RN, are transcription factors involved in neurotransmitter release, neuronal maturation and motor function processes among others. In our mutant mice, both transcription factors are lost, suggesting an abnormal maturation of the RN. The resulting altered nucleus occupied a wider territory. Finally, we examined RST development and found that the RN neurons were able to project to the spinal cord but their axons appeared defasciculated. These data suggest that Pou4f1 is necessary for the maturation of RN neurons but not for their specification and maintenance.Peer reviewedPeer Reviewe

Descriptores globales y locales de la reactividad para el diseño de nuevos fármacos anticancerosos basados en cis-platino(II)

Density functional theory was used to investigate the global and local reactivity of some cis-platinum(II) complexes including anticancer drugs, such as cisplatin and carboplatin. Calculated equilibrium geometries at mPW1PW/LANL2DZ* are in close agreement with their available X-ray data. We develop three new local reactivity descriptors: atomic descriptor of philicity, atomic descriptor group and atomic descriptor of philicity group for determining chemical reactivity and selectivity of the studied complexes. This contribution on chemical reactivity allow us to establish qualitative trends, which enable our descriptors for use in rational platinum based anticancer drug design

Case series of gallstone ileus: only enterolitotomy, one stage or two stage surgery?

Biliary ileus is a rare disease and an infrequent cause of intestinal obstruction, occasionally occurs in frail elderly patients and has a certain predilection for the female sex. The diagnosis is complex and requires a high clinical suspicion and complementary examinations such as abdominal radiography and contrasted abdominal tomography. Treatment should be individualized according to the clinical characteristics of each patient, with the alternatives being resolution only by enterolithotomy, one stage surgery and two stage surgery. We report 3 cases of biliary ileus, each one managed with a different surgical procedure. The decision was aimed at resolving the intestinal obstruction by enterolithotomy, and the definitive management was performed according to the clinical characteristics of each patient; however, there is no consensus or algorithm that recommends the ideal surgical technique. The recommended surgical procedure for the resolution of biliary ileus will be discussed

Nymphal feeding habits of two Anacroneuria species (Plecoptera, Perlidae) from Sierra Nevada de Santa Marta, Colombia

The knowledge of the diet of aquatic insects is important to assess the use of resources and overlap of trophic niche between species, as well as to understand their role in the food web of the freshwater ecosystems they inhabit. This is particularly necessary in tropical areas where information on this topic is scarce. The aim of the present work is to describe the feeding habits of the species Anacroneuria marta Zúñiga & Stark, 2002 and A. caraca Stark, 1995 in the middle section of the Río Gaira (Sierra Nevada de Santa Marta, Colombia). We sampled nymphs on three dates during the rainy and dry seasons in two major different microhabitats of the reach (leaf accumulations and gravel) in 2014. The nymphal diet of a total of 87 and 90 individuals of A. caraca and A. marta, respectively, was studied. With this information, niche breadth for each species and niche overlap between them in terms of trophic resources were calculated. The major trophic resource for both species in the dry and rainy season was the invertebrate animal matter. In the dry season, fine particulate organic matter was also important in the diet of A. caraca, and A. marta ingested a large quantity of coarse particulate organic matter in the rainy season. Larvae of Trichoptera were the most ingested prey in both species, followed by larvae of Chironomidae, Coleoptera Hydrophilidae, and nymphs of Ephemeroptera. No differences in diet between both species were detected, so this could favor niche overlap in terms of trophic resources and could lead to competition between them. The possible ecological scenarios are discussed

Soluble platelet-endothelial cell adhesion molecule-1, a biomarker of ventilator-induced lung injury

Introduction: Endothelial cell injury is an important component of acute lung injury. Platelet-endothelial cell adhesion molecule-1 (PECAM1) is a transmembrane protein that connects endothelial cells to one another and can be detected as a soluble, truncated protein (sPECAM1) in serum. We hypothesized that injurious mechanical ventilation (MV) leads to shedding of PECAM1 from lung endothelial cells resulting in increasing sPECAM1 levels in the systemic circulation. Methods: We studied 36 Sprague–Dawley rats in two prospective, randomized, controlled studies (healthy and septic) using established animal models of ventilator-induced lung injury. Animals (n = 6 in each group) were randomized to spontaneous breathing or two MV strategies: low tidal volume (VT) (6 ml/kg) and high-VT (20 ml/kg) on 2 cmH2O of positive end-expiratory pressure (PEEP). In low-VT septic animals, 10 cmH2O of PEEP was applied. We performed pulmonary histological and physiological evaluation and measured lung PECAM1 protein content and serum sPECAM1 levels after four hours ventilation period. Results: High-VT MV caused severe lung injury in healthy and septic animals, and decreased lung PECAM1 protein content (P < 0.001). Animals on high-VT had a four- to six-fold increase of mean sPECAM1 serum levels than the unventilated counterpart (35.4 ± 10.4 versus 5.6 ± 1.7 ng/ml in healthy rats; 156.8 ± 47.6 versus 35.6 ± 12.6 ng/ml in septic rats) (P < 0.0001). Low-VT MV prevented these changes. Levels of sPECAM1 in healthy animals on high-VT MV paralleled the sPECAM1 levels of non-ventilated septic animals. Conclusions: Our findings suggest that circulating sPECAM1 may represent a promising biomarker for the detection and monitoring of ventilator-induced lung injury

Factores asociados al consumo de tabaco en estudiantes universitarios de Lima metropolitana.: Factors associated with tobacco consumption in university students of Lima metropolitan

Introduction: The consumption of tobacco is very harmful to people’s health. According to WHO, smoking is the cause of death of 8 million people a year. Objetive: The purpose of the research was to determine the factors associated with the consumption of tobacco in university students in Metropolitan Lima. Methods: The sample consisted of 447 students from Lima universities, the survey was applied: Fagerstrom test. Subsequently the data was analyzed using tables of: distribution, frequency, contingency. &nbsp;Results: It was evidenced through the X2 statistical test that there is a significant association between the variables sex and smoking habit, OR = 1.93, IC 95%[1.29-6,519]. It was also observed that having smoking parents is significantly associated with the habit of smoking by the children, with a value p =0,000 of X2 and the OR 3.31, IC 95%[2,145 - 5,116]. Conclusion: The variables sex and parental background have a significant association with tobacco consumption, emphasizing that our family environment deserves to be safe, healthy and free of tobacco smokeIntroducción: El consumo de tabaco es muy perjudicial para la salud de las personas, según la OMS el tabaquismo es la causa de muerte de 8 millones de personas al año. Objetivo: El propósito de la investigación fue determinar los factores asociados al consumo de tabaco en estudiantes universitarios de Lima Metropolitana. Métodos: La muestra estuvo conformada por 447 estudiantes de universidades de Lima, se aplicó la encuesta: Test de Fagerstrom. Los datos fueron analizados utilizando tablas de distribución, frecuencia, y contingencia. Resultados: Se evidenció a través de la prueba estadística X2 que existe asociación significativa entre las variables sexo y el hábito de fumar, OR = 1.93, IC 95% [1.29 – 6,519].&nbsp; También se pudo observar que tener padres fumadores está asociado significativamente al hábito de fumar por parte de los hijos, con un valor de p=0,000 del X2 y el OR 3,31, IC 95% [2,145 – 5,116].&nbsp; Conclusión: Las variables sexo masculino y antecedentes parentales tienen asociación significativa con el consumo de tabaco enfatizando que nuestro entorno familiar merece ser seguro, saludable y libre del humo de tabaco

Composición y estructura de la ictiofauna del río Hondo, México-Belice, con base en el uso del arpón

ResumenSe determinó la composición y estructura de la ictiofauna del río Hondo y la variación espacial de éstas en función de los parámetros ambientales. Se realizaron 3 muestreos durante marzo, abril y mayo de 2012, en 6 sitios a lo largo del río. Los datos usados para determinar la estructura se obtuvieron con ayuda de un arpón de 58.5cm, utilizado durante 2h de buceo libre en cada punto de muestreo. Para complementar la lista de especies se utilizaron redes agalleras, palangres, nasas y anzuelos. Además, se realizó una revisión bibliográfica y se consultó material de la colección de peces de ECOSUR en Chetumal. La lista sistemática se conformó por 40 especies en 33 géneros, 18 familias y 11 órdenes. La familia mejor representada fue Cichlidae, incluida la especie exótica Oreochromis niloticus. Los parámetros ambientales que mejor describieron la variación de la distribución y abundancia en los peces en el río Hondo fueron: la anchura del río, distancia a la boca, transparencia, profundidad, concentración de oxígeno disuelto y conductividad. La relación entre las especies y las variables ambientales fue alta en ambos ejes (0.89 y 0.79). Ambientalmente, el río se puede zonificar en 3 partes, aunque su ictiofauna puede dividirse en 2 conjuntos principales.AbstractComposition and structure of the Hondo River ichthyofauna and its spatial variation were determined as a function of environmental parameters. Six sites along the river were sampled in March, April and May 2012. Data for estimating structure of fish assemblages was obtained by means of a 58.5cm harpoon during 2 hours of free diving at each sampling site. The species list for the study area was completed with the aid of gillnets, longlines, double-cone traps, and hook-and-line. In addition, a bibliographical research performed as well as the ichthyological collection of ECOSUR at Chetumal was checked. The systematic list includes 40 species in 33 genera, 18 families and 11 orders. The richest family was Cichlidae, including the exotic Oreochromis niloticus. The environmental parameters that best described distribution and abundance of fish in the Hondo River were river width, distance to mouth, transparency, depth, dissolved oxygen concentration, and conductivity. Correlation between species and environmental parameters was high in both axis (0.89 and 0.79). The river was classified into 3 environmental zones, although its fish fauna could be divided in 2 main assemblages

Acoplamiento molecular de potenciales inhibidores de Niemann Pick C1, involucrada en la transmisión del virus del Ébola

Abstract In this work, potential inhibitors of Ebola virus transmission were designed by analyzing the binding site of the Niemann Pick C1 protein, by means of molecular docking. For this investigation, a study of the binding site of the protein with cholesterol was carried out using the programs protein plus and Castp; Following this, the validation of the method was carried out using the Ligplot +, USCF Chimera software and AutoDockTools. Subsequently, molecules from other investigations were taken to study their interactions and based on this, new molecules were designed to which molecular coupling was applied to be able to choose the molecules with the best binding energies and finally a study was carried out on this selected group. Of the pharmacokinetic properties by means of Swiss ADME. Structures 18(a) and 22(b) presented the best results in the bioavailability radar, both present a high gastrointestinal absorption, comply with the Lipinski rules and their values ​​are within the established parameters, thus considering these molecules with great potential as inhibitors of the Ebola virus.Resumen En este trabajo se diseñaron potenciales inhibidores de la transmisión del virus del Ébola mediante el análisis del sitio de unión de la proteína Niemann Pick C1, por medio de acoplamiento molecular. Para esta investigación se hizo un estudio del sitio de unión de la proteína con el colesterol usando los programas protein plus y Castp; seguido a esto se realizó la validación del método utilizando los softwares Ligplot +, USCF Chimera y AutoDockTools. Posteriormente, se tomaron moléculas de otras investigaciones para estudiar sus interacciones y con base a esto se diseñaron nuevas moléculas a las cuales se les aplicó acoplamiento molecular para poder escoger las moléculas con mejores energías de unión y finalmente a este seleccionado grupo se les realizó un estudio de las propiedades farmacocinéticas por medio de Swiss ADME. Las estructuras 18 y 22 presentaron los mejores resultados en el radar de biodisponibilidad, ambas presentan una alta absorción gastrointestinal, cumplen con las reglas de Lipinski y sus valores están dentro de los parámetros establecidos, considerándose así estas moléculas con gran potencial como inhibidores del Virus del Èbola

Dispositivo de fijación, cierre y acoplamiento para catéter de perfusión intravenosa

Introducción: los medios de fijación a la piel de un catéter venoso periférico, de un catéter venoso central o de un catéter arterial central presentan los siguientes graves inconvenientes: ser la sede de infecciones a nivel del lugar de la punción, provocar una saturación de la zona anatómica, la cual resulta muy difícil de soportar e incómodo para el paciente portador, y suponer un riesgo para el personal de enfermería cuando se usan hilos de sutura para fijar el soporte del catéter. Objetivo: por lo anteriormente expuesto, se ha detectado la necesidad de diseñar un dispositivo que reduzca la complejidad y aparatosidad de los sistemas conocidos y empleados en la actualidad, favoreciendo la asepsia y la movilidad del paciente. Método: el desarrollo presentado en este artículo se refiere a un sistema mecánico de fijación, cierre y acoplamiento para catéter de perfusión intravenosa. El sistema dispone de una pieza circular de pequeño espesor con al menos dos orificios para su fijación subcutánea, centralmente de uno o más conductos para acoplar lúmenes, y de una parte cilíndrica hueca que sobresale a uno de los lados, exteriormente roscada e interiormente lisa con un tetón de posición. Para uso domiciliario se dispone de un tapón de estanqueidad con uno o más tubos de pequeño diámetro que se acoplan en los orificios para lúmenes, una ranura de posición, un tirador y un tapón roscado ciego para el cierre hermético con la parte roscada. Para uso hospitalario se dispone de un tapón intermedio con una o más entradas para lúmenes, así como de un tapón roscado hueco que permite su acoplamiento hermético con la parte roscada. Resultados: el desarrollo descrito en este artículo va a ser utilizado en dos ambientes: ambiente domiciliario y ambiente hospitalario. Además, reduce el riesgo de infección y saturación de la zona anatómica de los pacientes en los que se realiza la punción cutánea en la que se fijan catéteres venosos periféricos, catéteres venosos centrales o catéteres arteriales centralesIntroduction: skin fixing devices in peripheral, central or arterial catheters have several important drawbacks: site infection, stacking of material in the anatomical area which is very annoying for the patient and medical staff risk when fixating stitches are used. Objective: to develop a fixing device that simplifies presently used systems, favoring asepsis and motility. Methods: the device herein described is composed by a mechanical fixation, a closing system and coupling for intravenous catheters. The system has a thin circular piece with at least two holes for subcutaneous fixation, one or several conducts for lumina and a hollow cylindrical part in one side, screwed exteriorly and flat inside, with an oriented protuberance. A watertight plug with one or several thin tubes that adapt to the lumina, a positional slot, a handle and a solid screwed tap for perfect closure are available for at home use. An intermediate plug with one or several lumina and a screwed hollow plug are provided for in hospital use. Results: the above described device is intended to be used in two settings: in hospital and at home. It is supposed to reduce the risk of infection and stacking of the anatomical site where cutaneo us puncture with fixation of peripheral, central or arterial catheters is performe