82 research outputs found

    Interleukin-10-819 promoter polymorphism in association with gastric cancer risk

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    <p>Abstract</p> <p>Background</p> <p>Potential functional allele T/C single nucleotide polymorphism (SNP) of Interleukin 10 (IL-10) promoter -819 (rs1800871) has been implicated in gastric cancer risk. We aimed to explore the role of T/C SNP of IL-10 -819 in the susceptibility to gastric cancer through a systematic review and meta-analysis.</p> <p>Methods</p> <p>Each initially included article was scored for quality appraisal. Desirable data were extracted and registered into databases. 11 studies were ultimately eligible for the meta-analysis of IL-10 -819 T/C SNP. We adopted the most probably appropriate genetic model (recessive model). Potential sources of heterogeneity were sought out via subgroup and sensitivity analyses, and publication biases were estimated.</p> <p>Results</p> <p>IL-10 -819 TT genotype is associated with the overall reduced gastric cancer risk among Asians and even apparently observed among high quality subgroup Asians. IL-10-819 TT genotype is not statistically associated with the overall reduced gastric cancer susceptibility in persons with <it>H. pylori </it>infection compared with controls without <it>H. pylori </it>infection. IL-10 -819 TT genotype is reversely associated with diffuse-subtype risk but not in intestinal-subtype risk. IL-10 -819 TT genotype is not reversely associated with non-cardia or cardia subtype gastric cancer susceptibility.</p> <p>Conclusions</p> <p>IL-10 -819 TT genotype seems to be more protective from gastric cancer in Asians. Whether IL-10 -819 TT genotype may be protective from gastric cancer susceptibility in persons infected with <it>H. pylori </it>or in diffuse-subtype cancer needs further exploring in the future well-designed high quality studies among different ethnicity populations. Direct sequencing should be more used in the future.</p

    Molecular Structure of Selected Tuber and Root Starches and Effect of Amylopectin Structure on Their Physical Properties

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    The objectives of this study were to characterize starches isolated from potato, canna, fern, and kudzu, grown in Hangzhou, China, for potential food and nonfood applications and to gain understandings of the structures and properties of tuber and root starches. Potato and canna starches with B-type X-ray patterns had larger proportions of amylopectin (AP) long branch chains (DP g37) than did fern (C-type) and kudzu (CA-type) starches. The analysis of Naegeli dextrins suggested that fern and kudzu starches had more branch points, R-(1,6)-D-glycosidic linkages, located within the double-helical crystalline lamella than did the B-type starches. Dispersed molecular densities of the C- and CA-type APs (11.6-13.5 g/mol/nm3) were significantly larger than those of the B-type APs (1.4-6.1 g/mol/nm3) in dilute solutions. The larger proportion of the long AP branch chains in the B-type starch granules resulted in greater gelatinization enthalpy changes (ΔH). Retrograded kudzu starch, which had the shortest average chain length (DP 25.1), melted at a lower temperature (37.9 °C) than the others. Higher peak viscosities (550-749 RVU at 8%, dsb) of potato starches were attributed to the greater concentrations of phosphate monoesters, longer branch chains, and larger granule sizes compared with other tuber and root starches

    A reactive power-voltage control strategy of an AC microgrid based on adaptive virtual impedance

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    As an effective carrier of distributed generation, a microgrid is an effective way to ensure that distributed power can be reasonably utilized. However, due to the property of line impedance and other factors in a microgrid, reactive power supplied by distributed generation units cannot be shared rationally. To efficiently improve reactive power sharing, this paper proposes a reactive power-voltage control strategy based on adaptive virtual impedance. This method changes the voltage reference value by adding an adaptive term based on the traditional virtual impedance. Meanwhile, a voltage recovery mechanism was used to compensate the decline of distributed generation (DG) output voltage in the process. MATLAB/Simulink simulations and experimental results show that the proposed controller can effectively improve the steady state performance of the active and reactive power sharing. Finally, the feasibility and effectiveness of the proposed control strategy were verified

    Modélisation numérique de l'endommagement des matériaux poreux ductiles et application aux géomatériaux

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    Cette étude est consacrée à la modélisation numérique de l'endommagement pour des matériaux poreux ductiles et à des applications aux géomatériaux. On rappelle et analyse d'abord au chapitre 1 différentes approches d'endommagement pour la classe de matériaux étudiés. L'implantation numérique du modèle basé sur un critère macroscopique de type Gurson, récemment proposé par Monchiet et al.(2007) est effectué au chapitre 2. La bonne performance de ce nouveau modèle est vérifiée en comparant ses prédictions numériques à celles d'autres modèles de type Gurson. Dans le chapitre 3, les modélisations numériques sont étendues aux géomatériaux en implantant dans un code éléments finis un nouveau modèle formulé sur la base du critère de Guo et al.(2008) qui prend en compte de la compressibilité de la matrice. L'adéquation du modèle développé aux géomatériaux est démontrée à travers l'étude du comportement d'une craie. L'implantation numérique et l'analyse du modèle basé sur une version anisotrope du critère proposé par Monchiet et al.(2007) sont présentées au chapitre 4. Les résultats numériques issus de cette implantation sont discutés en les comparant aux ceux des autres modèles existants. Ils apparaissent tout à fait satisfaisantsThis study is devoted to the numerical modeling of damage for ductile porous materials and its applications to geomaterials. We first recall and analyze in chapter 1 different approaches of ductile damage. We then propose in chapter 2 a model based on the isotropic Gurson-type macroscopic criterion established by Monchietet al.(2007). This model is implemented numerically in ABAQUS Finite Element software. The good performance of this new model is checked by comparing its numerical predictions with the ones provided by other Gurson-type models. In chapter 3, numerical modelings are performed for geomaterials by implementing an appropriate model (based on Guo et al.(2008) criterion) in ABAQUS. The adequacy of the considered model to geomaterials is demonstrated through the study of a chalk. The numerical implementation and analysis of an anisotropic model based on the anisotropic version of the criterion proposed by Monchiet et al.(2007) are presented in chapter 4. The numerical results derived from this implementation are discussed with the results of others existing models. They appear to be quite satisfactory.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

    Microgravity experiments of two-phase flow patterns aboard mir space station

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    A first experimental study on two-phase how patterns at a long-term, steady microgravity condition was conducted on board the Russian Space Station "MIR" in August 1999. Carbogal and air are used as the liquid and the gas phase, respectively. Bubble, slug, slug-annular transitional, and annular hows are observed. A new region of annular how with lower liquid superficial velocity is discovered, and the region of the slug-annular transitional flow is wider than that observed by experiments on board the parabolic aircraft. The main patterns are bubble, slug-annular transitional and annular flows based on the experiments on board MIR space station. Some influences on the two-phase how patterns in the present experiments are discussed

    Subsoiling during summer fallow in rainfed winter-wheat fields enhances soil organic carbon sequestration on the Loess Plateau in China.

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    Scientific management of the soil organic carbon (SOC) pool, e.g., through a reasonable tillage system, is a potential way to mitigate global climate change. There is scarce information about the effect of tillage during the summer fallow period on the SOC pool in rainfed winter-wheat fields. The present study was designed to evaluate the effects of tillage practices, i.e., plow tillage (PTF), subsoiling (STF) and no tillage (NTF), during the summer fallow period on SOC sequestration in winter-wheat fields in the rainfed area of the eastern Loess Plateau of China. The SOC, mineral-associated organic carbon (MOC), permanganate-oxidizable organic carbon (POxC) and particulate organic carbon (POC) concentrations were determined after four years of tillage implementation during the summer fallow period. Our results showed that in comparison to the adoption of NTF, the adoption of STF significantly increased POxC, POC and MOC concentrations by 56.6-111.2%, 45.7-118.7% and 26.2-29.4%, respectively, at the 10-20 and 30-40 cm soil depths before sowing (P < 0.05). The POxC and MOC concentrations under STF at depths of 0-10, 10-20, 20-30 and 30-50 cm were significantly greater than those under PTF and NTF after harvesting (P < 0.05). In addition, the SOC concentration and SOC stock under STF were significantly greater than those under NTF at the 0-10, 10-20, 20-30 and 30-40 cm soil depths before sowing and after harvesting (P < 0.05). Furthermore, in comparison to PTF and NTF, STF resulted in significantly higher SOC stocks by 12.0-25.3% and 7.1-19.2% than PTF and NTF, respectively, in the 0-10, 0-20, 0-30, 0-40 and 0-50 cm soil profiles at harvesting (P < 0.05). In summary, the adoption of STF could be beneficial to the management of the SOC pool in the 0-50 cm soil profile in the rainfed area of winter-wheat on the Loess Plateau of China
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