Architecture of coatomer: Molecular characterization of delta-COP and protein interactions within the complex

Copyright © 2011 by The Rockefeller University Press.Coatomer is a cytosolic protein complex that forms the coat of COP I-coated transport vesicles. In our attempt to analyze the physical and functional interactions between its seven subunits (coat proteins, [COPs] alpha-zeta), we engaged in a program to clone and characterize the individual coatomer subunits. We have now cloned, sequenced, and overexpressed bovine alpha-COP, the 135-kD subunit of coatomer as well as delta-COP, the 57-kD subunit and have identified a yeast homolog of delta-COP by cDNA sequence comparison and by NH2-terminal peptide sequencing. delta-COP shows homologies to subunits of the clathrin adaptor complexes AP1 and AP2. We show that in Golgi-enriched membrane fractions, the protein is predominantly found in COP I-coated transport vesicles and in the budding regions of the Golgi membranes. A knock-out of the delta-COP gene in yeast is lethal. Immunoprecipitation, as well as analysis exploiting the two-hybrid system in a complete COP screen, showed physical interactions between alpha- and epsilon-COPs and between beta- and delta-COPs. Moreover, the two-hybrid system indicates interactions between gamma- and zeta-COPs as well as between alpha- and beta' COPs. We propose that these interactions reflect in vivo associations of those subunits and thus play a functional role in the assembly of coatomer and/or serve to maintain the molecular architecture of the complex.This work was supported by The Deutsche Forschungsgemeinschaft (SFB 352), the Human Frontier Science Program, and the Swiss National Science Foundation No. 31-43366.95

Gain degradation of a linear array due to random deformations

This paper deals with the gain degradation ofa lineararray when the signal spatial coherence is reduced by the random deformations of the line supporting the array. When the signal is imperfectly coherent, the gain is reduced by a sa called « gain degradation factor » which can be evaluated from the signal spatial coherence function and the array weighting function . In the case of random deformations of the array, an apparent signal spatial coherencefunction may be calculated from the stochastic model which characterizes the deformations. An expression of the gain degradation factor can then be deduced as a function of some reduced parameters which depend on frequency, array length, signal direction of arrival and the statistical parameters which characterize the deformations.Cet article présente une méthode qui permet de calculer la dégradation de gain d'une antenne linéaire lorsque la cohérence spatiale du signal se trouve limitée par les déformations aléatoires qui peuvent affecter la linéarité de l'antenne. Lorsqu'on se trouve en présence d'un signal imparfaitement cohérent le gain est réduit par un certain "facteur de dégradation" que l'on peut calculer à partir de la fonction de cohérence spatiale du signal et de la fonction de pondération de l'antenne. Dans le cas des déformations aléatoires de l'antenne, une fonction de cohérence spatiale apparente du signal peut être calculée à partir du modèle stochastique qui caractérise ces déformation

Effect of intestinal pressure on fistula closure during vacuum assisted treatment: A computational approach

AbstractBackgroundEnterocutaneous fistulae, pathological communications between the intestinal lumen and the abdominal skin, can arise as serious complication of gastrointestinal surgery. A current non-surgical treatment for this pathology involves topical application of sub-atmospheric pressure, also known as vacuum assisted closure (VAC). While this technique appears to be promising, surgeons report a number of cases in which its application fails to achieve fistula closure. Here, we evaluate the fistula’s physical properties during the vacuum assisted closure process in a computational approach exploring the relevance of intraluminal intestinal pressure.MethodsA mathematical model formulated by differential equations based on tissue elasticity properties and principles of fluid mechanics was created and forcing functions were integrated to mimic intestinal pressure dynamics. A software to solve equations and to fit the model to experimentally obtained data was developed. This enabled simulations of vacuum assisted fistula closure under different intestinal pressure.ResultsThe simulation output indicates conditions, in which fistula closure can or cannot be expected suggesting favoured or impeded healing, respectively. When modifications of intestinal pressure, as observed in fistula accompanying pathologies, are integrated, the outcome of fistula closure changes considerably. Rise of intestinal pressure is associated with delay of fistula closure and temporary fistula radius augmentation, while reduction of intestinal pressure during sub-atmospheric pressure treatment contributes to a faster and direct fistula closure.ConclusionFrom the model predictions, we conclude that administration of intestinal pressure decreasing compounds (e.g. butylscopolamine, glucagon) may improve VAC treatment, while intestinal pressure increasing drugs should be avoided

Effect of intestinal pressure on fistula closure during vacuum assisted treatment: A computational approach

Background: Enterocutaneous fistulae, pathological communications between the intestinal lumen and the abdominal skin, can arise as serious complication of gastrointestinal surgery. A current non-surgical treatment for this pathology involves topical application of sub-atmospheric pressure, also known as vacuum assisted closure (VAC). While this technique appears to be promising, surgeons report a number of cases in which its application fails to achieve fistula closure. Here, we evaluate the fistula's physical properties during the vacuum assisted closure process in a computational approach exploring the relevance of intraluminal intestinal pressure. Methods: A mathematical model formulated by differential equations based on tissue elasticity properties and principles of fluid mechanics was created and forcing functions were integrated to mimic intestinal pressure dynamics. A software to solve equations and to fit the model to experimentally obtained data was developed. This enabled simulations of vacuum assisted fistula closure under different intestinal pressure. Results: The simulation output indicates conditions, in which fistula closure can or cannot be expected suggesting favoured or impeded healing, respectively. When modifications of intestinal pressure, as observed in fistula accompanying pathologies, are integrated, the outcome of fistula closure changes considerably. Rise of intestinal pressure is associated with delay of fistula closure and temporary fistula radius augmentation, while reduction of intestinal pressure during sub-atmospheric pressure treatment contributes to a faster and direct fistula closure. Conclusion: From the model predictions, we conclude that administration of intestinal pressure decreasing compounds (e.g. butylscopolamine, glucagon) may improve VAC treatment, while intestinal pressure increasing drugs should be avoided.Facultad de Ciencias ExactasInstituto de Física de Líquidos y Sistemas Biológico

Description of the sensor outputs by means of a linear system in the array processing field

For a linear array with equispaced sensors, the sensor outputs may be efficiently described by a linear system . This general frame allows us to take into account classical physical hypotheses like plane wave hypothesis or spatial correlation of the noise received along the array ; this is achieved by means of state space modelling . This leads us to consider stochastic realization methods which have been developed in the general context of linear systems . Among these, a particular attention is focused on methods based on principal components ; links with array processing are presented . The performances of these methods are compared with the MUSIC method for simulated data.Pour une antenne linéaire à capteurs équidistants, la description des sorties des capteurs par un système linéaire fournit un cadre bien adapté à l'utilisation des hypothèses physiques. La prise en compte de l'hypothèse onde plane et de la corrélation spatiale du bruit le long de l'antenne par un modèle d'état nous conduit à considérer les méthodes de réalisation qui ont été développées pour l'étude des systèmes linéaires. Parmi celles-ci, on s'intéresse plus particulièrement aux méthodes fondées sur l'analyse en composantes principales, et on établit leurs liens avec le cadre habituel du traitement d'antenn

Memorias del Frente: Arqueología de campos de Batalla una serie documental

En este escrito buscamos describir y reflexionar en torno a la relación entre Arqueología y la práctica comunicativa de carácter audiovisual a partir de la experiencia vivida durante la producción, grabación y proyección del documental Memorias del Frente. Arqueología de campos de batalla. La serie, producida por Binar Media y emitida durante el 2021 por Canal Encuentro, se enfoca en las investigaciones arqueológicas de los campos de batalla desarrolladas en Argentina por diversos equipos a lo largo de las últimas dos décadas. También en la relación con las temáticas de memoria, identidad, valoración del patrimonio y la búsqueda de versiones más ricas respecto a nuestra historia nacional, las cuales pueden diferir de aquellas plasmadas por la historiografía tradicional. Así, en este trabajo indagamos acerca de las dinámicas relacionales acaecidas entre sus protagonistas –arqueólogos y equipo de filmación–, los vínculos interdisciplinarios establecidos entre la Arqueología y la Ciencia de la comunicación para la difusión pública del conocimiento, así como aquellos ocurridos entre los arqueólogos y la sociedad en general, en pos de la puesta en valor del patrimonio.This paper describes and reflects on the relationship between Archeology and the audiovisual communicative practice based on the experience lived during the production, recording and projection of the documentary Memorias del Frente. Archeology of battlefields, that was produced by Binar Media and broadcast in Canal Encuentro during 2021. This documentary develops the archaeological investigations of battlefields carried out in Argentina by various research teams over the last two decades. Also approaches in subjects related to memory, identity, the enhancement of heritage and the different and alternative approaches respect to traditional historiography. Thus, this work explores the relational dynamics between its protagonists –archaeologists and film crew–, the interdisciplinary established among Archeology and the science of communication for the public dissemination of knowledge as well as the relationship between archaeologists and the society, in pursuit of the enhancement of heritage.Fil: Ravazzola, Alejandro Mario. Universidad de Buenos Aires. Facultad de Ciencias Sociales; Argentina. Binar Media Sociedad de Responsabilidad Limitada.; ArgentinaFil: Landa, Carlos Gilberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Arqueología; ArgentinaFil: Raies, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Humanidades y Artes; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Arqueología; Argentina. Universidad Nacional de Luján; Argentin

Territorios virtuales y campos de batalla. El uso de mapas digitales como espacios multimedia de estudio y divulgación

The technological development of the last decades has provided multiple possibilities of communication with different audiences. New tools and media complement and optimize existing ones and also require the construction of new types of narratives, together with the formation of multidisciplinary teams that combine different knowhows. In this work we explore the application of digital recording and dissemination tools to the archaeological-historical study of armed conflicts and military outposts of the 18th and 19th centuries, for academic research purposes and multiplatform dissemination accessible to a non-specialized public.El desarrollo tecnológico de las últimas décadas ha proporcionado múltiples posibilidades de comunicación con diversos públicos. Nuevas herramientas y canales complementan y optimizan las preexistentes y exigen también la construcción de nuevos tipos de relato, junto a la conformación de equipos multidisciplinarios que combinen diferentes saberes. En este trabajo exploramos la aplicación de herramientas digitales de registro y difusión al estudio arqueológico-histórico de los conflictos armados y asentamientos militares de frontera de los siglos XVIII y XIX, con fines investigativos académicos y de difusión multiplataforma accesible para un público no especializado

Management of external small bowel fistulae: Challenges and controversies confronting the general surgeon

Background: External small bowel fistulae (ESBF) are serious complications that represent a major challenge for general surgeons. They are still associated with significant morbidity and mortality. This article reviews the management of ESBF with emphasis on the treatment using sub-atmospheric pressure as well a timing, strategies and techniques of reconstructive surgery. Methods: Relevant articles from 1960 to 2010 were identified using various electronic databases to review randomized controlled trials, prospective observational studies, retrospective studies and case reports and highlight key references. Conclusions: External small bowel fistulae require multidisciplinary management and multimodal approaches with a primary essential focus on early recognition and diminishment of mortality factors such as sepsis and malnutrition. In most cases, the initial treatment is conservative, including clinical and nutritional recovery, output control and extensive local wound care. At this stage, the application of local negative pressure is highly effective. This procedure also allows for a spontaneous closure in many patients. Other cases require careful consideration of surgical reconstruction, knowing that success rates are variable and largely dependent on the patient's condition as well as on local aspects of the lesion. Best surgical results are obtained via intra-peritoneal access with extensive enterolysis, resection of the bowel segment from which the fistulae originate and direct abdominal wall closure.Facultad de Ciencias Exacta