Cultiu i desenvolupament in vitro d'embrions humans

En gairebé trenta anys les tècniques de reproducció humana assistida s'han universalitzat i alhora s'ha aconseguit augmentar-ne l'èxit gràcies a millores tant en l'aspecte clínic com en el del laboratori. Tradicionalment, s'ha utilitzat el criteri morfològic (avaluació de les característiques morfològiques de l'embrió) per seleccionar els millors embrions per transferir. No obstant això, el valor predictiu d'aquest criteri és força limitat i, amb vista a augmentar les taxes de gestació, les transferències de més d'un embrió són les més habituals, amb el conseqüent risc de gestació múltiple. Així, el repte actual en reproducció humana assistida és aconseguir la gestació única mitjançant la reducció del nombre d'embrions transferits a un. Caldrà, doncs, millorar els medis de cultiu per permetre seleccionar embrions en estadis més avançats i alhora disposar de criteris d'avaluació que correlacionin eficaçment les característiques de l'embrió amb la seva viabilitat. Actualment, els esforços s'encaminen en dues direccions: la primera, el desenvolupament del criteri morfològic, amb la tendència a un sistema d'avaluació seqüencial de l'embrió en diferents estadis, i la segona, molt més nova, la recerca de noves tècniques no invasives basades en l'anàlisi dels constituents de l'embrió i del seu metabolisme.During the past three decades the practice of clinical assisted reproduction have grown world-wide and moreover the success rate has increased thanks to clinical and laboratory improvements. Tradicionally, the morphological criteria has been applied to select embryos to transfer. However, the predictive value of this criteria is limited so that the multiple- embryo transfers are very common leading to a higher risc of multiple pregnancy. The goal in assisted reproduction is achieving a single pregnancy through the reduction of the number of embryos used in transfer to one. Single embryo transfer requires culture media to improve in order to allow the embryo selection in more advanced stages as well as having a reliable method to evaluate the embryo viability. Nowadays, strategies are carrying out in two different fields: the first one, continuing in morphometric criteria, it tends to use a sequencial scoring system from the oocyte through to the cleavage-stage embryo to allow selecting the most viable embryo in a cohort and the second one, in the research field, the development of new techniques based on the analysis of the embryo constitution and its metabolism

Migration-Related Conflicts as Drivers of Institutional Change?

This article examines the role of social conflicts in the context of migration and discusses the relation between such conflicts and institutional change. We understand conflicts as tensions that evoke contradiction between different social groups or institutional actors. Varied urban contexts together with dynamic immigration of heterogeneous population groups can induce negotiation processes that affect institutional settings and actors. Conflicts have therefore been an integral part of urban coexistence, and cities have always been places where these conflicts play out. We assume that conflicts are social phenomena, which have multiple causes and effects. Public assumptions about conflicts in connection with migration often have a negative or destructive impetus, while conflict theory ascribes to conflicts potential positive effects on societal change. Conflicts can represent forms of socialization and the possibility of adapting or changing social conditions. This article discusses the extent to which migration-related conflicts induce institutional change. Using qualitative empirical results from the BMBF-funded research project MigraChance, we present a case study that reconstructs the emergence and course of a conflict surrounding the construction of a Syriac-Orthodox church in Bebra (Hesse) in the 1990s. Analyzing this conflict both in depth and in relation to its local context, we show that migration is only one part of what we refer to as migration-related conflicts, and we shed light on the complexity of factors that can result in institutional change. Change can also occur indirectly, in small steps, and with ambivalent normative implications

Films of starch and poly(butylene adipate co-terephthalate) added of soybean oil (SO) and Tween 80

AbstractStarch extruded in the presence of a plasticizer results in a material called thermoplastic starch (TPS). TPS mixed with poly(butylene adipate co-terephthalate) (PBAT), soybean oil (SO), and surfactant may result in films with improved mechanical properties due to greater hydrophobicity and compatibility among the polymers. This study characterized films produced from blends containing 65% TPS and 35% PBAT with SO added as compatibilizer. The Tween 80 was added to prevention of phase separation. The elongation and resistance were greater in the films with SO. The infrared spectra confirmed an increase in ester groups bonded to the PBAT and the presence of groups bonded to the starch ring, indicating TPS–SO and PBAT–SO interactions. The micrographs suggest that the films with SO were more homogenous. Thus, SO is considered to be a good compatibilizer for blends of TPS and PBAT

Supply Chain Design and Inventory Management Optimization in the Motors Industry

This article studies the supply chain redesign under demand uncertainty over a multi-period planning. We propose an optimization model to solve the problem taking into account strategic and tactical plans. This model is applied to the electric motors industry but it can be easily extended to other supply chains. Long term decisions involve new installations, expansions and elimination of warehouses. Tactical decisions include deciding inventory levels (safety stock and expected inventory) for each type of product in distribution centers and customer plants, as well as the connection links between the supply chain nodes. Capacity constraints are also considered when planning inventory levels. At the tactical level it is analyzed how demand of failing motors is satisfied, and whether to use new or used motors. The uncertain demand is addressed by defining the optimal amount of safety stock that guarantees certain service level at a customer plant. In addition, the risk-pooling effect is taken into account when defining inventory levels in distribution centers and customer zones. Due to the nonlinear nature of the original formulation, a piecewise linearization approach is applied to obtain a tight lower bound of the optimal solution.Fil: Rodriguez, Maria Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo y Diseño (i); ArgentinaFil: Vecchietti, Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo y Diseño (i); ArgentinaFil: Grossmann, Ignacion E.. University Of Carnegie Mellon; Estados UnidosFil: Harjunskonsky, Liro. ABB AG, Corporate Research Germany; Alemani

Chagas disease treatment efficacy markers: experiences from a Phase III study with nifurtimox in children

Determining the success of antitrypanosomal therapy for Chagas disease is challenging, particularly in the chronic phase of the disease, because seropositivity persists for a long time after successful antitrypanosomal treatment and is known to be related to the duration of Trypanosoma cruzi infection. Seroconversion to negative by two or more conventional serologic tests is the currently accepted measure of efficacy, and studies suggest no significant change in seropositivity if left untreated. However, there is no guidance for industry on how to establish the effectiveness of drugs intended for the treatment of Chagas disease. Due to the lack of validated sensitive, specific, easy-to-use markers that allow early monitoring of the efficacy of antitrypanosomal treatment in an efficient manner, we used seroreduction measured by two conventional enzyme-linked immunosorbent assays in addition to the currently accepted criterion for what constitutes a cure, seroconversion to negative, as a surrogate parameter for efficacy in a Phase III pediatric trial with nifurtimox. The measures for confirmation of the antitrypanosomal efficacy of nifurtimox were discussed with US FDA. In this perspective article, we present our experiences obtained from a pediatric study on Chagas disease with an established drug using a surrogate efficacy parameter in addition to the established criterion for a cure