35 research outputs found
Polyfunctional fluorosilicone composition, method for making, and use
A fluorosilicone crosslinker and method for making is provided. Reaction is effected between a silanol terminated polyfluoroalkyl silicone fluid and a polyalkoxysilane in the presence of a Platinum Group Metal catalyst. The fluorosilicone crosslinker can be used in combination with a silanol terminated fluoroalkyl substituted polydiorganosiloxane to formulate a neutral, condensation curable, solvent resistant sealant
Copolymer sealant compositions and method for making
Condensation curable poly(fluoroorgano)siloxane-poly(silarylene)siloxane block copolymer compositions having a glass transition temperature not exceeding about -54.degree. C. and excellent solvent resistance have been found useful as sealants. Polyalkoxysilylorgano compounds, such as 1,4-bis[trimethoxysilyl(ethyl)]benzene have been found to be effective as cross-linkers
Copolymer sealant compositions and method for making
Condensation curable poly(fluoroorgano)siloxane-poly(silarylene)siloxane block copolymer compositions having a glass transition temperature not exceeding about -54.degree. C. and excellent solvent resistance have been found useful as sealants. Polyalkoxysilylorgano compounds, such as 1,4-bis[trimethoxysilyl(ethyl)]benzene have been found to be effective as cross-linkers
A comprehensive review of techniques for natural fibers as reinforcement in composites::preparation, processing and characterization
Designing environmentally friendly materials from natural resources represents a great challenge in the last decade. However, the lack of fundamental knowledge in the processing of the raw materials to fabricate the composites structure is still a major challenge for potential applications.Natural fibers extracted from plants are receiving more attention from researchers, scientists and academics due to their use in polymer composites and also their environmentally friendly nature and sustainability. The natural fiber features depend on the preparation and processing of the fibers. Natural plant fibers are extracted either by mechanical retting, dew retting and/or water retting processes. The natural fibers characteristics could be improved by suitable chemicals and surface treatments. This survey proposes a detailed review of the different types of retting processes, chemical and surface treatments and characterization techniques for natural fibers. We summarize major findings from the literature and the treatment effects on the properties of the natural fibers are being highlighted
Mapping genetic variations to three- dimensional protein structures to enhance variant interpretation: a proposed framework
The translation of personal genomics to precision medicine depends on the accurate interpretation of the multitude of genetic variants observed for each individual. However, even when genetic variants are predicted to modify a protein, their functional implications may be unclear. Many diseases are caused by genetic variants affecting important protein features, such as enzyme active sites or interaction interfaces. The scientific community has catalogued millions of genetic variants in genomic databases and thousands of protein structures in the Protein Data Bank. Mapping mutations onto three-dimensional (3D) structures enables atomic-level analyses of protein positions that may be important for the stability or formation of interactions; these may explain the effect of mutations and in some cases even open a path for targeted drug development. To accelerate progress in the integration of these data types, we held a two-day Gene Variation to 3D (GVto3D) workshop to report on the latest advances and to discuss unmet needs. The overarching goal of the workshop was to address the question: what can be done together as a community to advance the integration of genetic variants and 3D protein structures that could not be done by a single investigator or laboratory? Here we describe the workshop outcomes, review the state of the field, and propose the development of a framework with which to promote progress in this arena. The framework will include a set of standard formats, common ontologies, a common application programming interface to enable interoperation of the resources, and a Tool Registry to make it easy to find and apply the tools to specific analysis problems. Interoperability will enable integration of diverse data sources and tools and collaborative development of variant effect prediction methods
Musical agency reduces perceived exertion during strenuous physical performance
Music is known to be capable of reducing perceived exertion during strenuous physical activity. The current interpretation of this modulating effect of music is that music may be perceived as a diversion from unpleasant proprioceptive sensations that go along with exhaustion. Here we investigated the effects of music on perceived exertion during a physically strenuous task, varying musical agency, a task that relies on the experience of body proprioception, rather than simply diverting from it. For this we measured psychologically indicated exertion during physical workout with and without musical agency while simultaneously acquiring metabolic values with spirometry. Results showed that musical agency significantly decreased perceived exertion during workout, indicating that musical agency may actually facilitate physically strenuous activities. This indicates that the positive effect of music on perceived exertion cannot always be explained by an effect of diversion from proprioceptive feedback. Furthermore, this finding suggests that the down-modulating effect of musical agency on perceived exertion may be a previously un-acknowledged driving force for the development of music in humans: making music makes strenuous physical activities less exhausting
Oxidative Addition, Transmetalation, and Reductive Elimination at a 2,2-Bipyridyl-Ligated Gold Center
Oxidative Addition, Transmetalation, and Reductive Elimination at a 2,2′-Bipyridyl-Ligated Gold Center
Three-coordinate
bipyridyl complexes of gold, [(κ<sup>2</sup>-bipy)Au(η<sup>2</sup>-C<sub>2</sub>H<sub>4</sub>)][NTf<sub>2</sub>], are readily
accessed by direct reaction of 2,2′-bipyridine
(bipy), or its derivatives, with the homoleptic gold ethylene complex
[Au(C<sub>2</sub>H<sub>4</sub>)<sub>3</sub>][NTf<sub>2</sub>]. The
cheap and readily available bipyridyl ligands facilitate oxidative
addition of aryl iodides to the Au(I) center to give [(κ<sup>2</sup>-bipy)Au(Ar)I][NTf<sub>2</sub>], which undergo first aryl-zinc
transmetalation and second C–C reductive elimination to produce
biaryl products. The products of each distinct step have been characterized.
Computational techniques are used to probe the mechanism of the oxidative
addition step, offering insight into both the origin of the reversibility
of this process and the observation that electron-rich aryl iodides
add faster than electron-poor substrates. Thus, for the first time,
all steps that are characteristic of a conventional intermolecular
Pd(0)-catalyzed biaryl synthesis are demonstrated from a common monometallic
Au complex and in the absence of directing groups