374 research outputs found

    DEVELOPMENT OF "Luftain -Tg" AS A MICROISOLATION CAGE SYSTEM

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    Developed "Luftain Tg" to include cage and luck for the breeding, nowadays an experiment increases as exchanging it digest gene set, and breeding, experiment of Transgenic mouse (following Tg mouse) increases. Doesn't exit the front of luck to outside as giving and doing a mind directly to cage inside, as a ceremony as hanging bathtub type cage-we controlled with a curtain and developed a system to defend from an expansion of cage inside and outside contamination. Again, for flowing of these air computer simulation even though were able to confirm it.Tgマウスの飼育に適し、かつ、飼育作業性の良いラックの開発を行った。バスタブ型ケージを吊り式とし、天井/吊りレール/背面側塞ぎ板により上方3方を閉鎖しケージからの排気出口は上前面のケージ鍔上のみとした。ケージ-の上後方からの直接給気とケージからの排気の流れは架台前面をエアカーテンで制御し、架台後方より排気することによりケージ内外の汚染の伝播を防止する機構になっており、コンピューター・シミュレーション及び気流可視化試験によりその効果が確認できた

    Temperature-Dependent Thermal Conductivity of Undoped Polycrystalline Silicon Layers

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    Polycrystalline silicon is used in microelectronic and microelectromechanical devices for which thermal design is important. This work measures the in-plane thermal conductivities of free-standing undoped polycrystalline layers between 20 and 300 K. The layers have a thickness of 1 μm, and the measurements are performed using steady-state Joule heating and electrical-resistance thermometry in patterned aluminum microbridges. The layer thermal conductivities are found to depend strongly on the details of the deposition process through the grain size distribution, which is investigated using atomic force microscopy and transmission electron microscopy. The room-temperature thermal conductivity of as-grown polycrystalline silicon is found to be 13.8 W·m -1 ·K -1 and that of amorphous recrystallized polycrystalline silicon is 22 W·m -1 ·K -1 , which is almost an order of magnitude less than that of single-crystal silicon. The maximum thermal conductivities of both samples occur at higher temperatures than in pure single-crystalline silicon layers of the same thickness. The data are interpreted using the approximate solution to the Boltzmann transport equation in the relaxation time approximation together with Matthiessen's rule. These measurements contribute to the understanding of the relative importance of phonon scattering on grain and layer boundaries in polysilicon films and provide data relevant for the design of micromachined structures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44568/1/10765_2004_Article_297892.pd

    Geography-dependent horizontal gene transfer from vertebrate predators to their prey

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    Horizontal transfer (HT) of genes between multicellular animals, once thought to be extremely rare, is being more commonly detected, but its global geographic trend and transfer mechanism have not been investigated. We discovered a unique HT pattern of Bovine-B (BovB) LINE retrotransposons in vertebrates, with a bizarre transfer direction from predators (snakes) to their prey (frogs). At least 54 instances of BovB HT were detected, which we estimate to have occurred across time between 85 and 1.3 Ma. Using comprehensive transcontinental sampling, our study demonstrates that BovB HT is highly prevalent in one geographical region, Madagascar, suggesting important regional differences in the occurrence of HTs. We discovered parasite vectors that may plausibly transmit BovB and found that the proportion of BovB-positive parasites is also high in Madagascar where BovB thus might be physically transported by parasites to diverse vertebrates, potentially including humans. Remarkably, in two frog lineages, BovB HT occurred after migration from a non-HT area (Africa) to the HT hotspot (Madagascar). These results provide a novel perspective on how the prevalence of parasites influences the occurrence of HT in a region, similar to pathogens and their vectors in some endemic diseases

    Coexpression Analysis of Tomato Genes and Experimental Verification of Coordinated Expression of Genes Found in a Functionally Enriched Coexpression Module

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    Gene-to-gene coexpression analysis is a powerful approach to infer the function of uncharacterized genes. Here, we report comprehensive identification of coexpression gene modules of tomato (Solanum lycopersicum) and experimental verification of coordinated expression of module member genes. On the basis of the gene-to-gene correlation coefficient calculated from 67 microarray hybridization data points, we performed a network-based analysis. This facilitated the identification of 199 coexpression modules. A gene ontology annotation search revealed that 75 out of the 199 modules are enriched with genes associated with common functional categories. To verify the coexpression relationships between module member genes, we focused on one module enriched with genes associated with the flavonoid biosynthetic pathway. A non-enzyme, non-transcription factor gene encoding a zinc finger protein in this module was overexpressed in S. lycopersicum cultivar Micro-Tom, and expression levels of flavonoid pathway genes were investigated. Flavonoid pathway genes included in the module were up-regulated in the plant overexpressing the zinc finger gene. This result demonstrates that coexpression modules, at least the ones identified in this study, represent actual transcriptional coordination between genes, and can facilitate the inference of tomato gene function

    Stearoyl-CoA Desaturase-1 (SCD1) Augments Saturated Fatty Acid-Induced Lipid Accumulation and Inhibits Apoptosis in Cardiac Myocytes

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    Mismatch between the uptake and utilization of long-chain fatty acids in the myocardium leads to abnormally high intracellular fatty acid concentration, which ultimately induces myocardial dysfunction. Stearoyl-Coenzyme A desaturase-1 (SCD1) is a rate-limiting enzyme that converts saturated fatty acids (SFAs) to monounsaturated fatty acids. Previous studies have shown that SCD1-deficinent mice are protected from insulin resistance and diet-induced obesity; however, the role of SCD1 in the heart remains to be determined. We examined the expression of SCD1 in obese rat hearts induced by a sucrose-rich diet for 3 months. We also examined the effect of SCD1 on myocardial energy metabolism and apoptotic cell death in neonatal rat cardiac myocytes in the presence of SFAs. Here we showed that the expression of SCD1 increases 3.6-fold without measurable change in the expression of lipogenic genes in the heart of rats fed a high-sucrose diet. Forced SCD1 expression augmented palmitic acid-induced lipid accumulation, but attenuated excess fatty acid oxidation and restored reduced glucose oxidation. Of importance, SCD1 substantially inhibited SFA-induced caspase 3 activation, ceramide synthesis, diacylglycerol synthesis, apoptotic cell death, and mitochondrial reactive oxygen species (ROS) generation. Experiments using SCD1 siRNA confirmed these observations. Furthermore, we showed that exposure of cardiac myocytes to glucose and insulin induced SCD1 expression. Our results indicate that SCD1 is highly regulated by a metabolic syndrome component in the heart, and such induction of SCD1 serves to alleviate SFA-induced adverse fatty acid catabolism, and eventually to prevent SFAs-induced apoptosis
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