607 research outputs found

    SMAD7 polymorphisms and colorectal cancer risk: a meta-analysis of case-control studies

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    Mothers against decapentaplegic homolog 7 (SMAD7) inhibits the transforming growth factor-β (TGF-β) signaling pathway, which regulates carcinogenesis and cancer progression. A number of studies have reported that SMAD7 polymorphisms (rs4464148, rs4939827, and rs12953717) are associated with colorectal cancer (CRC) risk, but the results from these studies remain conflicting. To determine a more precise estimation of the relationship between SMAD7 and CRC, we undertook a large-scale meta-analysis of 63 studies, which included a total of 187,181 subjects (86,585 cases and 100,596 controls). The results of our meta-analysis revealed that the C allele of rs4464148 [CC vs. TT+TC, odds ratio (OR) =1.23, 95% confidence interval (CI): 1.14-1.33, P < 0.01], the T allele of rs4939827 [TT vs. CC+TC, odds ratio OR=1.15, 95%CI:1.07-1.22, P < 0.01] and the T allele of rs12953717 [TT vs. CC+TC, OR =1.22, 95%CI:1.16-1.29, P < 0.01] were all associated with the increased CRC risk. Subgroup analysis according to ethnicity showed rs4464148 and rs12953717 were associated with the risk of CRC in both Caucasians and Asians, whereas rs4939827 was a risk polymorphism for CRC specifically in Caucasians. In summary, this large-scale meta-analysis indicated that SMAD7 polymorphisms (rs4464148, rs4939827, and rs12953717) correlate with CRC

    Lifetime Prediction method of LED Light-emitting Device Based on Approximate Analysis

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    Compared with other light sources, LED light source has a longer service life and will not suddenly fail. Due to its high efficiency, energy saving and long life, LED has become the most popular light source at present. However, it is no longer considered to meet the application requirements, and the time that the light flux decays to this level is considered to be the life of the LED. This paper introduces the approximate method used to predict the lumen maintenance life of LED lamps. The experimental results obtained by the approximate method are compared with the TM-21 standard. Eventually, it is concluded that the approximate method provides more reliability information than the original TM-21 standard, and the obtained results are more reference, more accurate and more reliable

    Fabrication of α-FeSi2 nanowhiskers and nanoblades via electron beam physical vapor deposition

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    Iron disilicide nanowhiskers and nanoblades are synthesized by depositing Fe onto Si(100) substrates at about 900 degrees C via electron beam physical vapor deposition. The nanostructures are determined as single crystalline alpha-FeSi2 with tetragonal lattice. The nanostructures are stable with prolong exposure under ambient condition, and no transformation towards beta-FeSi2 is detected after 2 h annealing at 500 degrees C and 800 degrees C under high vacuum condition (10(-6) mbar). The growth directions of the whiskers are found as either [001] or [100]. However, in the blades we observe grow only in [100] crystallographic direction. Changing cross-sectional shape of the alpha-FeSi2 whiskers from octagon at the root to rectangle at the upper part is observed and believed to be a result of the thermodynamic and kinetic anisotropy. SiO2 layer formed on the surface of the structures because of its lower surface energy compared to all iron oxides. By this a passivation, which prevents further oxidization, of the nanowhiskers is achieved. The alpha-FeSi2 whiskers form by root growth. (C) 2019 The Authors. Published by Elsevier Ltd
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