20 research outputs found

    Solid chamber for satellite electronic modules and evaluation of its heat conduction behavior

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    A novel solid chamber configuration for cooling satellite electronic modules enduring high heat is proposed. Solid chamber modules with different inner structures and solid materials with high thermal conductivity are designed, and their thermal performances were experimentally studied. The equivalent heat conduction coefficient and contact thermal resistance of a solid chamber module are defined and the estimation methods for the thermal behavior are proposed. It is found that the thermal performances of the two solid chamber modules with the inner structures respectively composed of Graphite/Al 630/30 composites and graphite plate are obviously better than those of the other modules. Based on the assessment of the thermal resistance and cracks generated in the modules after thermal tests, it is found that the powder metallurgy technology makes the interlayers bonded more tightly than diffusion welding in the manufacture of solid chamber, and the tightness of the interlayer interface plays a key role in the contact thermal resistance

    In-situ carbonization approach for the binder-free Ir-dispersed ordered mesoporous carbon hydrogen evolution electrode

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    A binder-free Ir-dispersed ordered mesoporous carbon (Ir-OMC) catalytic electrode has been prepared through a designed in-situ carbonization method, which involves coating resorcinol and formaldehyde mixtures with iridium precursors onto the three-dimensional nickel foam framework, followed by in-situ calcination in N-2 atmosphere at 800 degrees C for 3 h. This electrode shows a large surface area, ordered mesoporous structure and homogeneous distribution of metal nanoparticles. It presents good activity and stability towards hydrogen evolution reaction, which is attributed to the efficient mass and electron transport from the intimate contact among Ir nanoparticles, ordered mesoporous carbon matrix and 3D conductive substrate. We hope that this in-situ carbonization synthetic route can also be applied to design more high-performance catalysts for water splitting, fuel cells and other clean energy devices. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved

    <it>De Novo</it> characterization of the banana root transcriptome and analysis of gene expression under <it>Fusarium oxysporum</it> f. sp. <it>Cubense</it> tropical race 4 infection

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    <p>Abstract</p> <p>Background</p> <p>Bananas and plantains (Musa spp.) are among the most important crops in the world due to their nutritional and export value. However, banana production has been devastated by fungal infestations caused by <it>Fusarium oxysporum</it> f. sp. <it>cubense</it> (Foc), which cannot be effectively prevented or controlled. Since there is very little known about the molecular mechanism of Foc infections; therefore, we aimed to investigate the transcriptional changes induced by Foc in banana roots.</p> <p>Results</p> <p>We generated a cDNA library from total RNA isolated from banana roots infected with Foc Tropical Race 4 (Foc TR 4) at days 0, 2, 4, and 6. We generated over 26 million high-quality reads from the cDNA library using deep sequencing and assembled 25,158 distinct gene sequences by <it>de novo</it> assembly and gap-filling. The average distinct gene sequence length was 1,439 base pairs. A total of 21,622 (85.94%) unique sequences were annotated and 11,611 were assigned to specific metabolic pathways using the Kyoto Encyclopedia of Genes and Genomes database. We used digital gene expression (DGE) profiling to investigate the transcriptional changes in the banana root upon Foc TR4 infection. The expression of genes in the Phenylalanine metabolism, phenylpropanoid biosynthesis and alpha-linolenic acid metabolism pathways was affected by Foc TR4 infection.</p> <p>Conclusion</p> <p>The combination of RNA-Seq and DGE analysis provides a powerful method for analyzing the banana root transcriptome and investigating the transcriptional changes during the response of banana genes to Foc TR4 infection. The assembled banana transcriptome provides an important resource for future investigations about the banana crop as well as the diseases that plague this valuable staple food.</p

    Evaluating Different Extraction Approaches for GC-MS Based Metabolomics Analysis of the Giant Pandas’ Fur

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    Giant pandas in zoo captivity are situated in residential areas, where environmental pollutants and anthropogenic factors have an impact on their health. Hair metabolomics has been applied in numerous environmental toxicological studies. Therefore, the panda fur metabolome could be a reliable approach to reflect endogenous and exogenous metabolic changes related to environmental exposure. However, there is no established extraction protocol to study the fur metabolome of pandas. The aim of this research was to optimize the extraction of panda fur metabolome for high-throughput metabolomics analysis using gas chromatography-mass spectrometry. Fur samples were collected from five pandas. Eight different extraction methods were investigated and evaluated for their reproducibility, metabolite coverage, and extraction efficiency, particularly in relation to the biochemical compound classes such as amino acids, tricarboxylic acid cycle derivatives, fatty acids, and secondary metabolites. Our results demonstrated that HCl + ACN were the superior extraction solvents for amino acid and secondary metabolite extraction, and NaOH + MeOH was ideal for fatty acid extraction. Interestingly, the metabolomic analysis of panda fur was capable of discriminating the longitudinal metabolite profile between black and white furs. These extraction protocols can be used in future study protocols for the analysis of the fur metabolome in pandas

    Follistatin-Like 1: A Potential Mediator of Inflammation in Obesity

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    Obesity is associated with a state of chronic low-grade inflammation, which contributes to insulin resistance and type 2 diabetes. However, the molecular mechanisms that link obesity to inflammation are not fully understood. Follistatin-like 1 (FSTL1) is a novel proinflammatory cytokine that is expressed in adipose tissue and secreted by preadipocytes/adipocytes. We aimed to test whether FSTL1 could have a role in obesity-induced inflammation and insulin resistance. It was found that FSTL1 expression was markedly decreased during differentiation of 3T3-L1 preadipocytes but reinduced by TNF-α. Furthermore, a significant increase in FSTL1 levels was observed in adipose tissue of obese ob/ob mice, as well as in serum of overweight/obese subjects. Mechanistic studies revealed that FSTL1 induced inflammatory responses in both 3T3-L1 adipocytes and RAW264.7 macrophages. The expression of proinflammatory mediators including IL-6, TNF-α, and MCP-1 was upregulated by recombinant FSTL1 in a dose-dependent manner, paralleled with activation of the IKKβ-NFκB and JNK signaling pathways in the two cell lines. Moreover, FSTL1 impaired insulin signaling in 3T3-L1 adipocytes, as revealed by attenuated phosphorylation of both Akt and IRS-1 in response to insulin stimulation. Together, our results suggest that FSTL1 is a potential mediator of inflammation and insulin resistance in obesity

    Highly efficient and durable MoNiNC catalyst for hydrogen evolution reaction

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    We report a carbothermal ammonia reduction (CAR) strategy for one-pot preparation of highly efficient and durable hydrogen evolution reaction (HER) electrocatalyst composed of earth abundant early transition metals. In this strategy, resin is applied both as the pre-binder and carbon source, and Pluronic F127 as the structuredirecting agent. Upon annealing in NH3, the Mo-containing precursor on Ni foam undergoes the CAR, and simultaneously Ni from the substrate diffuses out, resulting in the formation of a quaternary complex structure of molybdenum-nickel bimetallic carbonitride (MoNiNC). The as-prepared electrode showed outstanding HER performance with an overpotential of 150 mV at 50 mA cm(-2) and maintained steady hydrogen bubble evolution for continuous 48 h. Our strategy offers a quick and simple way to fabricate earth-abundant HER electrode with highly efficient and durable electrocatalytic performance

    Exploring BH2CN-based hydrophobic hypergolic fuels and effective fuel "additives": Imidazolylidene cyanoborane complexes

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    Two hydrophobic imidazolylidene-cyanoborane complexes were prepared by the introduction of {BH2CN} into the molecular formula via treatment of imidazolium iodide and NaBH3CN avoiding literature's tedious and hazardous procedures. These two complexes were fully characterized using IR spectroscopy, H-1 NMR and C-13 NMR spectroscopy and high-resolution mass spectrometer. The X-Ray structure of NHC-1 has been determined. NHC-2 was proved to be hypergolic with WFNA and displayed the attractive properties such as water immiscibility, wide liquid range (T-g = -22 degrees C), short ignition delay time (13 ms), high density (0.98 g/cm(3)), good density impulse (rho I-sp 347 s g cm(-3)), showing the promising application potential as a fuel and an efficient fuel additive. (C) 2017 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved

    Genome-wide analysis of methylation in giant pandas with cataract by methylation-dependent restriction-site associated DNA sequencing (MethylRAD).

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    The giant panda (Ailuropoda melanoleuca) is a native species to China. They are rare and endangered and are regarded as the 'national treasure' and 'living fossil' in China. For the time being, there are only about 2500 giant pandas in the world. Therefore, we still have to do much more efforts to protect the giant pandas. In captive wildlife, the cataract incidence of mammalian always increases with age. Currently, in China, the proportion of elderly giant pandas who suffering from cataract has reached 20%. The eye disorder thus has a strong influence on the physical health and life quality of the elderly giant pandas. To discover the genes associated with the pathogenesis of cataract in the elderly giant panda and achieve the goal of early assessment and diagnosis of cataract in giant pandas during aging, we performed whole genome methylation sequencing in 3 giant pandas with cataract and 3 healthy giant pandas using methylation-dependent restriction-site associated DNA sequencing (MethylRAD). In the present study, we obtained 3.62M reads, on average, for each sample, and identified 116 and 242 differentially methylated genes (DMGs) between the two groups under the context of CCGG and CCWGG on genome, respectively. Further KEGG and GO enrichment analyses determined a total of 110 DMGs that are involved in the biological functions associated with pathogenesis of cataract. Among them, 6 DMGs including EEA1, GARS, SLITRK4, GSTM3, CASP3, and EGLN3 have been linked with cataract in old age
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