283 research outputs found

    Transitions/relaxations in polyester adhesive/PET system

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    The correlations between the transitions and the dielectric relaxation processes of the oriented poly(ethylene terephthalate) (PET) pre-impregnated of the polyester thermoplastic adhesive have been investigated by differential scanning calorimetry (DSC) and dynamic dielectric spectroscopy (DDS). The thermoplastic polyester adhesive and the oriented PET films have been studied as reference samples. This study evidences that the adhesive chain segments is responsible for the physical structure evolution in the PET-oriented film. The transitions and dielectric relaxation modes’ evolutions in the glass transition region appear characteristic of the interphase between adhesive and PET film, which is discussed in terms of molecular mobility. The storage at room temperature of the adhesive tape involves the heterogeneity of the physical structure, characterized by glass transition dissociation. Thus, the correlation between the transitions and the dielectric relaxation processes evidences a segregation of the amorphous phases. Therefore, the physical structure and the properties of the material have been linked to the chemical characteristics

    Numerical visualization and optimization on the core penetration in multi-cavity co-injection molding with a bifurcation runner structure

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    [[abstract]]Co-Injection Molding and multi-cavity molding are common processes for plastic products manufacturing. These two systems are sometimes combined and applied in the manufacture of bifurcation-structure products. In the previous literature results, the dynamic behavior of the core penetration in co-injection multi-cavity molding with a bifurcation structure is quite complicated and the behavior is sensitive to injection flow rates, different materials, and other process conditions. However, how these influential factors truly affect the core penetration behavior and the detailed mechanism of core penetration behavior has not yet been fully understood. In this study, we focused on studying the multi-cavity co-injection system with a bifurcation runner structure. The results showed that when the skin-to-core ratio is fixed (say 72/28), the melt flow behavior of a co-injection system, utilizing the same material for both skin and core, is very similar to that of a single shot injection molding. Specifically, the non-symmetrical bifurcation runner structure will influence the flow behavior greatly and cause the core distribution imbalance between different cavities. Due to the geometric nature of the bifurcation runner design, this core distribution imbalance problem will still persist even if we modify the melt temperature, mold temperature, or even change the plastic material. Furthermore, when the skin-to-core ratio is fixed (say 72/28), the changes of the flow rate have very little effect on the core penetration result in the final molded product; the final molded product will still have a core distribution imbalance issue. However, we observed that when the flow rate is increased, the core material will occupy more volume space in the upstream portion of the runner and the core penetration distance will be reduced in the flow direction downstream. This feature is very useful to further manipulate the skin-core interface in a multi-cavity system. Moreover, regarding how to improve a poor inter-cavity balance of core material distribution, using a suitable adjustment of the skin-to-core ratio will be greatly helpful. However, the core break-through defect can be a common problem in co-injection molding when an unsuitable skin-to-core ratio is used. To prevent the core break-through defect, increasing the flow rate properly can be one of the good options that we can use. Hence, we concluded that a suitable adjustment of the skin-to-core ratio and a proper flow rate control can be used to optimize the core material distribution in multi-cavity co-injection molding with a bifurcation runner structure. Lastly, in order to validate our inference and the effectiveness of our proposal to improve the inter-cavity imbalance and core break-through problem, a series of experimental studies were performed. And, all experimental results are in good agreement with those of our numerical predictions to further validate the feasibility of our proposed method to gain a better control of the core material distribution with a bifurcation runner structure in multi-cavity co-injection molding.[[notice]]補正完

    The descriptive content of names as predicate modifiers

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    In this paper I argue that descriptive content associated with a proper name can serve as a truth-conditionally relevant adjunct and be an additional contribution of the name to the truth-conditions. Definite descriptions the so-and-so associated by speakers with a proper name can be used as qualifying prepositional phrases as so-and-so, so sentences containing a proper name NN is doing something could be understood as NN is doing something as NN (which means as so-and-so). Used as an adjunct, the descriptive content of a proper name expresses the additional circumstances of an action (a manner, reason, goal, time or purpose) and constitute a part of a predicate. I argue that qualifying prepositional phrases should be analyzed as predicate modifiers and propose a formal representation of modified predicates. The additional truth-conditional relevance of the descriptive content of a proper name helps to explain the phenomenon of the substitution failure of coreferential names in simple sentences

    Effect of particle size, coupling agent and DDGS additions on Paulownia wood polypropylene composites

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    Studies aimed at improving the tensile, flexural, impact, thermal, and physical characteristics of wood–plastic composites composed of Paulownia wood flour derived from 36-month-old trees blended with polypropylene were conducted. Composites of 25% and 40% w/w of Paulownia wood were produced by twin-screw compounding and injection molding. Composites containing 0–10% by weight of maleated polypropylene were evaluated and an optimum maleated polypropylene concentration determined, i.e., 5%. The particle size distribution of Paulownia wood filler is shown to have an effect on the tensile and flexural properties of the composites. Novel combination composites of dried distiller’s grain with solubles mixed with Paulownia wood (up to 40% w/w) were produced and their properties evaluated. Depending on the composite tested, soaking composites for 872 h alters mechanical properties and causes weight gain

    High-throughput sequencing of the DBA/2J mouse genome

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    The DBA/2J mouse is not only the oldest inbred strain, but also one of the most widely used strains. DBA/2J exhibits many unique anatomical, physiological, and behavior traits. In addition, DBA/2J is one parent of the large BXD family of recombinant inbred strains [1]. The genome of the other parent of this BXD family— C57BL/6J—has been sequenced and serves as the mouse reference genome [2]. We sequenced the genome of DBA/2J using SOLiD and Illumina high throughput short read protocols to generate a comprehensive set of ~5 million sequence variants segregating in the BXD family that ultimately cause developmental, anatomical, functional and behavioral differences among these 80+ strains

    A Minimal Model of Metabolism Based Chemotaxis

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    Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominantly studied as metabolism-independent. All available simulation models of bacterial chemotaxis endorse this assumption. Recent studies have shown, however, that many metabolism-dependent chemotactic patterns occur in bacteria. We hereby present the simplest artificial protocell model capable of performing metabolism-based chemotaxis. The model serves as a proof of concept to show how even the simplest metabolism can sustain chemotactic patterns of varying sophistication. It also reproduces a set of phenomena that have recently attracted attention on bacterial chemotaxis and provides insights about alternative mechanisms that could instantiate them. We conclude that relaxing the metabolism-independent assumption provides important theoretical advances, forces us to rethink some established pre-conceptions and may help us better understand unexplored and poorly understood aspects of bacterial chemotaxis

    Region-Specific Responses of Adductor Longus Muscle to Gravitational Load-Dependent Activity in Wistar Hannover Rats

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    Response of adductor longus (AL) muscle to gravitational unloading and reloading was studied. Male Wistar Hannover rats (5-wk old) were hindlimb-unloaded for 16 days with or without 16-day ambulation recovery. The electromyogram (EMG) activity in AL decreased after acute unloading, but that in the rostral region was even elevated during continuous unloading. The EMG levels in the caudal region gradually increased up to 6th day, but decreased again. Approximately 97% of fibers in the caudal region were pure type I at the beginning of experiment. Mean percentage of type I fibers in the rostral region was 61% and that of type I+II and II fiber was 14 and 25%, respectively. The percent type I fibers decreased and de novo appearance of type I+II was noted after unloading. But the fiber phenotype in caudal, not rostral and middle, region was normalized after 16-day ambulation. Pronounced atrophy after unloading and re-growth following ambulation was noted in type I fibers of the caudal region. Sarcomere length in the caudal region was passively shortened during unloading, but that in the rostral region was unchanged or even stretched slightly. Growth-associated increase of myonuclear number seen in the caudal region of control rats was inhibited by unloading. Number of mitotic active satellite cells decreased after unloading only in the caudal region. It was indicated that the responses of fiber properties in AL to unloading and reloading were closely related to the region-specific neural and mechanical activities, being the caudal region more responsive

    Widespread horizontal transfer of mitochondrial genes in flowering plants

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    Horizontal gene transfer - the exchange of genes across mating barriers - is recognized as a major force in bacterial evolution(1,2). However, in eukaryotes it is prevalent only in certain phagotrophic protists and limited largely to the ancient acquisition of bacterial genes(3-5). Although the human genome was initially reported(6) to contain over 100 genes acquired during vertebrate evolution from bacteria, this claim was immediately and repeatedly rebutted(7,8). Moreover, horizontal transfer is unknown within the evolution of animals, plants and fungi except in the special context of mobile genetic elements(9-12). Here we show, however, that standard mitochondrial genes, encoding ribosomal and respiratory proteins, are subject to evolutionarily frequent horizontal transfer between distantly related flowering plants. These transfers have created a variety of genomic outcomes, including gene duplication, recapture of genes lost through transfer to the nucleus, and chimaeric, half-monocot, half-dicot genes. These results imply the existence of mechanisms for the delivery of DNA between unrelated plants, indicate that horizontal transfer is also a force in plant nuclear genomes, and are discussed in the contexts of plant molecular phylogeny and genetically modified plants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62688/1/nature01743.pd

    The usability of recycled carbon fibres in short fibre thermoplastics: interfacial properties

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    The objective of this study was to investigate the feasibility of combining discontinuous recycled carbon fibres with polypropylene, to produce a low-cost, high specific stiffness material for high-volume applications. The inherent low affinity of carbon fibre and polypropylene motivated a detailed study of the surface characteristics of carbon fibre and interfacial behaviour between the two materials, using the microbond test. The effects of removing the sizing from the fibres, as well as introducing a maleic anhydride-grafted polypropylene coupling agent, were extensively investigated. Polypropylene was found to degrade when prepared under atmospheric conditions; therefore, it was necessary to form droplets under nitrogen. Removal of the sizing from the fibre using pyrolysis and solvolysis techniques altered the surface morphology of the fibre and increased the interfacial shear strength (IFSS) by 4 and 33 %, respectively. A more significant improvement in the fibre–matrix adhesion was achieved by adding a maleic anhydride coupling agent at 2 wt%, which increased the IFSS by 320 %

    Bio-informatics analysis of a gene co-expression module in adipose tissue containing the diet-responsive gene Nnat

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    Background: Obesity causes insulin resistance in target tissues - skeletal muscle, adipose tissue, liver and the brain. Insulin resistance predisposes to type-2 diabetes (T2D) and cardiovascular disease (CVD). Adipose tissue inflammation is an essential characteristic of obesity and insulin resistance. Neuronatin (Nnat) expression has been found to be altered in a number of conditions related to inflammatory or metabolic disturbance, but its physiological roles and regulatory mechanisms in adipose tissue, brain, pancreatic islets and other tissues are not understood. Results: We identified transcription factor binding sites (TFBS) conserved in the Nnat promoter, and transcription factors (TF) abundantly expressed in adipose tissue. These include transcription factors concerned with the control of: adipogenesis (Ppar gamma, Klf15, Irf1, Creb1, Egr2, Gata3); lipogenesis (Mlxipl, Srebp1c); inflammation (Jun, Stat3); insulin signalling and diabetes susceptibility (Foxo1, Tcf7l2). We also identified NeuroD1 the only documented TF that controls Nnat expression. We identified KEGG pathways significantly associated with Nnat expression, including positive correlations with inflammation and negative correlations with metabolic pathways (most prominently oxidative phosphorylation, glycolysis and gluconeogenesis, pyruvate metabolism) and protein turnover. 27 genes, including; Gstt1 and Sod3, concerned with oxidative stress; Sncg and Cxcl9 concerned with inflammation; Ebf1, Lgals12 and Fzd4 involved in adipogenesis; whose expression co-varies with Nnat were identified, and conserved transcription factor binding sites identified on their promoters. Functional networks relating to each of these genes were identified. Conclusions: Our analysis shows that Nnat is an acute diet-responsive gene in white adipose tissue and hypothalamus; it may play an important role in metabolism, adipogenesis, and resolution of oxidative stress and inflammation in response to dietary exces
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