Kinetics analysis and simulation of sequential epoxy dual-curing systems with independent thermal activation

The curing kinetics of a sequential dual-curing system based on an off-stoichiometric amine-epoxy formulation with intermediate latent reactivity has been analyzed. The first curing stage is an epoxy-amine polycondensation taking place at low temperatures, while the second curing stage is an anionic homopolymerization of the excess epoxy groups, taking place at high temperatures and catalyzed by a latent base. The different reactivity of both polymerization processes allows an excellent separation into well-defined curing stages each of which can be analyzed individually. The kinetics of the two curing stages have been analyzed by integral isoconversional procedures and model-fitting methods. Both methodologies successfully simulated each curing stage and also the global curing process, showing that it is possible to control the activation of both curing stages. Isoconversional integral analysis is a simple yet powerful method that can be used for the simulation of temperature-controlled curing programmes. Model-fitting analysis is more suitable for the flexible simulation of processing scenarios such as the curing of composites.Postprint (author's final draft

Beneficial effects of αB-crystallin in spinal cord contusion injury

αB-crystallin is a member of the heat shock protein family that exerts cell protection under several stress-related conditions. Recent studies have revealed that αB-crystallin plays a beneficial role in a mouse model of multiple sclerosis, brain ischemia, and Alexander disease. Whether αB-crystallin plays a role in modulating the secondary damage after CNS trauma is not known. We report here that αB-crystallin mediates protective effects after spinal cord injury. The levels of αB-crystallin are reduced in spinal cord tissue following contusion lesion. In addition, administration of recombinant human αB-crystallin for the first week after contusion injury leads to sustained improvement in locomotor skills and amelioration of secondary tissue damage. We also provide evidence that recombinant human αB-crystallin modulates the inflammatory response in the injured spinal cord, leading to increased infiltration of granulocytes and reduced recruitment of inflammatory macrophages. Furthermore, the delivery of recombinant human αB-crystallin promotes greater locomotor recovery even when the treatment is initiated 6 h after spinal cord injury. Our findings suggest that administration of recombinant human αB-crystallin may be a good therapeutic approach for treating acute spinal cord injury, for which there is currently no effective treatment

Maresin 1 promotes inflammatory resolution, neuroprotection, and functional neurological recovery after Spinal Cord Injury

Resolution of inflammation is defective after spinal cord injury (SCI), which impairs tissue integrity and remodeling and leads to functional deficits. Effective pharmacological treatments for SCI are not currently available. Maresin 1 (MaR1) is a highly conserved specialized proresolving mediator (SPM) hosting potent anti-inflammatory and proresolving properties with potent tissue regenerative actions. Here, we provide evidence that the inappropriate biosynthesis of SPM in the lesioned spinal cord hampers the resolution of inflammation and leads to deleterious consequences on neurological outcome in adult female mice. We report that, after spinal cord contusion injury in adult female mice, the biosynthesis of SPM is not induced in the lesion site up to 2 weeks after injury. Exogenous administration of MaR1, a highly conserved SPM, propagated inflammatory resolution after SCI, as revealed by accelerated clearance of neutrophils and a reduction in macrophage accumulation at the lesion site. In the search of mechanisms underlying the proresolving actions of MaR1 in SCI, we found that this SPM facilitated several hallmarks of resolution of inflammation, including reduction of proinflammatory cytokines (CXCL1, CXCL2, CCL3, CCL4, IL6, and CSF3), silencing of major inflammatory intracellular signaling cascades (STAT1, STAT3, STAT5, p38, and ERK1/2), redirection of macrophage activation toward a prorepair phenotype, and increase of the phagocytic engulfment of neutrophils by macrophages. Interestingly, MaR1 administration improved locomotor recovery significantly and mitigated secondary injury progression in a clinical relevant model of SCI. These findings suggest that proresolution, immunoresolvent therapies constitute a novel approach to improving neurological recovery after acute SCI.SIGNIFICANCE STATEMENT Inflammation is a protective response to injury or infection. To result in tissue homeostasis, inflammation has to resolve over time. Incomplete or delayed resolution leads to detrimental effects, including propagated tissue damage and impaired wound healing, as occurs after spinal cord injury (SCI). We report that inflammation after SCI is dysregulated in part due to inappropriate synthesis of proresolving lipid mediators. We demonstrate that the administration of the resolution agonist referred to as maresin 1 (MaR1) after SCI actively propagates resolution processes at the lesion site and improves neurological outcome. MaR1 is identified as an interventional candidate to attenuate dysregulated lesional inflammation and to restore functional recovery after SCI

Structural and Dynamical Patterns on Online Social Networks: the Spanish May 15th Movement as a case study

The number of people using online social networks in their everyday life is continuously growing at a pace never saw before. This new kind of communication has an enormous impact on opinions, cultural trends, information spreading and even in the commercial success of new products. More importantly, social online networks have revealed as a fundamental organizing mechanism in recent country-wide social movements. In this paper, we provide a quantitative analysis of the structural and dynamical patterns emerging from the activity of an online social network around the ongoing May 15th (15M) movement in Spain. Our network is made up by users that exchanged tweets in a time period of one month, which includes the birth and stabilization of the 15M movement. We characterize in depth the growth of such dynamical network and find that it is scale-free with communities at the mesoscale. We also find that its dynamics exhibits typical features of critical systems such as robustness and power-law distributions for several quantities. Remarkably, we report that the patterns characterizing the spreading dynamics are asymmetric, giving rise to a clear distinction between information sources and sinks. Our study represent a first step towards the use of data from online social media to comprehend modern societal dynamics.Comment: 16 pages, 7 figure

Cystic Echinococcosis in Spain: Current Situation and Relevance for Other Endemic Areas in Europe

Cystic echinococcosis (CE) remains an important health problem in many regions of the world, both where no control measures have been implemented, and where control programs have been incompletely successful with ensuing re-emergence of the disease. In Spain, official data on CE show an increase in the proportion of intermediate hosts with CE during the last few years, and autochthonous pediatric patients have been reported, a sign of active local transmission of disease. A similar picture emerges from data reported to the European Food Safety Authority by other European countries. Nevertheless, several crucial aspects related to CE that would help better understand and control the disease have not been tackled appropriately, in particular the emergence of infection in specific geographical areas. In this respect, while some data are missing, other data are conflicting because they come from different databases. We review the current situation of CE in Spain compared with areas in which similar problems in the CE field exist, and offer recommendations on how to overcome those limitations. Specifically, we believe that the introduction of national registries for CE with online data entry, following the example set by the European Registry for Alveolar Echinococcosis, would help streamline data collection on CE by eliminating the need for evaluating and integrating data from multiple regions, by avoiding duplication of data from patients who access several different health facilities over time, and by providing much needed clinical and epidemiological data that are currently accessible only to clinicians

1,4-Butanediol as a Reducing Agent in Transfer Hydrogenation Reactions

1,4-Butanediol is able to deliver two equivalents of H(2) in hydrogen-transfer reactions to ketones, imines, and alkenes. Unlike simple alcohols, which establish equilibrium in the reduction of ketones, 1,4-butanediol acts essentially irreversibly owing to the formation of butyrolactone, which acts as a thermodynamic sink. It is therefore not necessary to use 1,4-butanediol in great excess in order to achieve reduction reactions. In addition, allylic alcohols are reduced to saturated alcohols through an isomerization/reduction sequence using a ruthenium catalyst with 1,4-butanediol as the reducing agent. Imines and alkenes are also reduced under similar conditions

Simulación virtual del ruido de tráfico en ciudades con elaboración de los mapas sonoros

Congreso Internacional de Comunicación, Tecnología y Educación (3º. 2000. Oviedo

Kinetics analysis and simulation of sequential epoxy dual-curing systems with independent thermal activation

The curing kinetics of a sequential dual-curing system based on an off-stoichiometric amine-epoxy formulation with intermediate latent reactivity has been analyzed. The first curing stage is an epoxy-amine polycondensation taking place at low temperatures, while the second curing stage is an anionic homopolymerization of the excess epoxy groups, taking place at high temperatures and catalyzed by a latent base. The different reactivity of both polymerization processes allows an excellent separation into well-defined curing stages each of which can be analyzed individually. The kinetics of the two curing stages have been analyzed by integral isoconversional procedures and model-fitting methods. Both methodologies successfully simulated each curing stage and also the global curing process, showing that it is possible to control the activation of both curing stages. Isoconversional integral analysis is a simple yet powerful method that can be used for the simulation of temperature-controlled curing programmes. Model-fitting analysis is more suitable for the flexible simulation of processing scenarios such as the curing of composites

New epoxy thermosets with improved toughness by adding hyperbranched polymer modifiers

Postprint (published version