219 research outputs found

    Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

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    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing

    Genome-wide identification of β-1,3-glucanase genes in Hevea brasiliensis

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    β-1,3-glucanase is one of the pathogenesis-related proteins well-known for their antifungal properties which can be abundantly found in Hevea brasiliensis. Utilization of β-1,3-glucanase in the genetic improvement of H. brasiliensis is very important as the high susceptibility to various fungal infections has challenged the current natural rubber industry. A few nucleotide sequences for β-1,3-glucanase have been reported and their role in biotic stress management has been demonstrated. Being a multigene family, it is necessary to identify and characterize more isoforms of β-1,3-glucanase to select the most suitable isoform to be utilized in genetic improvement. In the current study, we conducted a genome-wide identification of β-1,3-glucanases in H. brasiliensis, their classification based on the functional domains and phylogenetic analysis, using different bioinformatics tools. All publicly available nucleotide sequences were collected and curated by eliminating sequences that lack glycoside hydrolase family 17 (GH 17) domain as well as the partial and closely identical sequences and obtained 14 full-length sequences. The sequences were categorized into 4 distinct classes (I-IV) based on their functional domains and C-terminal extension. Class III and IV which lack the carbohydrate-binding C-terminal X8 domain are the largest classes identified with 5 β-1,3-glucanase each while 4 β-1,3-glucanase contain a variable C-terminal X8 domain. Phylogenetic analysis showed the clustering of β-1,3-glucanases into six major clades (I-VI) based on the domains. Clades I and II were identified as the largest clades with 4 β-1,3-glucanase in each. Several paralogous clusters have been observed for H. brasiliensis indicating the gene family expansion within the species or in the immediate ancestors with possible species-specific function. Further functional characterization is necessary to select the suitable gene to be utilized in genetic improvement and the present study provides a platform for it

    Brain grey matter volume alterations associated with antidepressant response in major depressive disorder

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    Not all patients with major depressive disorder respond to adequate pharmacological therapy. Psychoradiological studies have reported that antidepressant responders and nonresponders show different alterations in brain grey matter, but the findings are inconsistent. The present study reports a meta-analysis of voxel-based morphometric studies of patients with major depressive disorder, both antidepressant responders and nonresponders, using the anisotropic effect size version of Seed-based D Mapping to identify brain regions correlated to clinical response. A systematic search was conducted up to June 2016 to identify studies focussing on antidepressant response. In responders across 9 datasets grey matter volume (GMV) was significantly higher in the left inferior frontal gyrus and insula, while GMV was significantly lower in the bilateral anterior cingulate cortex (ACC) and the right superior frontal gyrus (SFG). In nonresponders across 5 datasets GMV was significantly lower in the bilateral ACC, median cingulate cortex (MCC) and right SFG. Conjunction analysis confirmed significant differences in the bilateral ACC and right SFG, where GMV was significantly lower in nonresponders but higher in responders. The current study adds to psychoradiology, an evolving subspecialty of radiology mainly for psychiatry and clinical psychology

    The incorporation of coconut water and banana homogenate in the regeneration of fig (Ficus carica L.) cv. Violette de Solliès

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    The common fig (Ficus carica L.) is from the family of Moraceae and is commonly cultivated for its fruits, which are well-known for their exceptional nutritional and medicinal properties. The addition of organic additives functions to supply carbon sources and other essential vitamins, minerals, and natural growth regulators to support the growth of explants. The present study aims to assess the effects of coconut water and banana homogenate in the regeneration of Ficus carica cv. Violette de Solliès (VDS). In vitro shoot, explants were cultured in full-strength MS medium without sucrose but with 1.0 mg/L BAP and different concentrations of coconut water and banana homogenate. Results indicated that MS media with 200 mL/L coconut water resulted in the highest number of induced shoots (3.03 ± 0.122) and shoot height (1.005 ± 0.022 cm) compared to other treatments with coconut water, whereas MS media supplemented with 200 g/L banana homogenate produced the highest number of induced shoots (3.00 ± 0.144) and the highest shoot height (0.958 ± 0.020 cm) of all the banana homogenate treatments. In conclusion, coconut water and banana homogenate are suitable alternatives for carbon sources and other organic growth factors contributing to the regeneration of Ficus carica cv. VDS

    Meat tenderness: advances in biology, biochemistry, molecular mechanisms and new technologies

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    Meat tenderness is an important quality trait critical to consumer acceptance, and determines satisfaction, repeat purchase and willingness-to-pay premium prices. Recent advances in tenderness research from a variety of perspectives are presented. Our understanding of molecular factors influencing tenderization are discussed in relation to glycolysis, calcium release, protease activation, apoptosis and heat shock proteins, the use of proteomic analysis for monitoring changes, proteomic biomarkers and oxidative/nitrosative stress. Each of these structural, metabolic and molecular determinants of meat tenderness are then discussed in greater detail in relation to animal variation, postmortem influences, and changes during cooking, with a focus on recent advances. Innovations in postmortem technologies and enzymes for meat tenderization are discussed including their potential commercial application. Continued success of the meat industry relies on ongoing advances in our understanding, and in industry innovation. The recent advances in fundamental and applied research on meat tenderness in relation to the various sectors of the supply chain will enable such innovation

    Enhanced nitrogen and phosphorus flows in a mixed land use basin: drivers and consequences

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    Rapid increase in accumulation of phosphorus (P) relative to nitrogen (N) has been observed in human-impacted regions, but the reasons are largely unknown. We developed an Integrated Nutrient Flow Analysis (INFA) model in order to assess the changes in nutrient flows of the Chaohu Lake basin from 1978 to 2015. Results show that the increase in total N input is slower than that of P (3.5-fold versus 4.2-fold) during 1978–2015, while total N loss increases much faster than that of P (3.1-fold versus 2.3-fold). We found a decline trend in the N:P ratio of nutrient input and accumulation since the mid-1990s. The decline in N:P ratio of nutrient loss to waterbodies in the basin is correlated (p < 0.05) with TN:TP of water concentration in Chaohu Lake, which may be related to the frequent algal blooms in the P-limited lake by supplying more P than N. Using an extended STIRPAT model, we found that nutrient use efficiency, urban rate, diet choice and population are key factors driving the change in nutrient flows, which contribute over 90% to the total change. This study confirms that human activities decrease N:P in regional environment and demonstrates the importance of P management to balance nutrient for improving water quality. The method in this study has a wide application for many other mixed land use regions to address nutrient flows imbalance problems and to explore nutrient management options

    Guanxi, IT Systems, and Innovation Capability: The Moderating Role of Proactiveness

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    In Chinese exporting, small and medium-sized companies (SMEs) need to be innovative to develop a competitive advantage. This research explored how these organizations can use two resources: 1) guanxi with customers, distributors, suppliers, and government officials; and 2) IT systems to enhance their innovation capabilities and new product performance. The moderating role of an organization’s proactiveness with respect to new product development is also examined. The resource-based view provides the theoretical support for the research. A conceptual model is developed and tested using survey data gathered from 210 Chinese SMEs in manufacturing industries that were analyzed using SmartPLS 2.0. Results show that IT systems are positively related to innovation capability. The relationship between guanxi and innovation capability is significant for firms that exhibit high levels of proactiveness but not when proactiveness is low
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