641 research outputs found

    Localization of matters on thick branes

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    AbstractWe study localization of various spin fields on flat thick branes, two different models are considered. For spin 0 scalar field, the massless zero mode is found to be normalizable on both the thick brane models. Spin 1 vector field cannot be normalizable on either of the two brane models. And for spin 1/2 field there is no bound zero mode for both the left and right chiral fermions. In order to localize the left or right chiral fermions on the thick brane models, the usual Yukawa scalar-fermion coupling is considered. It is shown that, the two models give different localization properties for fermions. Namely, whether there is a bound zero mode is related to the considered model

    Localization of matters on thick branes

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    AbstractWe study localization of various spin fields on flat thick branes, two different models are considered. For spin 0 scalar field, the massless zero mode is found to be normalizable on both the thick brane models. Spin 1 vector field cannot be normalizable on either of the two brane models. And for spin 1/2 field there is no bound zero mode for both the left and right chiral fermions. In order to localize the left or right chiral fermions on the thick brane models, the usual Yukawa scalar-fermion coupling is considered. It is shown that, the two models give different localization properties for fermions. Namely, whether there is a bound zero mode is related to the considered model

    Converting normal insulators into topological insulators via tuning orbital levels

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    Tuning the spin-orbit coupling strength via foreign element doping and/or modifying bonding strength via strain engineering are the major routes to convert normal insulators to topological insulators. We here propose an alternative strategy to realize topological phase transition by tuning the orbital level. Following this strategy, our first-principles calculations demonstrate that a topological phase transition in some cubic perovskite-type compounds CsGeBr3_3 and CsSnBr3_3 could be facilitated by carbon substitutional doping. Such unique topological phase transition predominantly results from the lower orbital energy of the carbon dopant, which can pull down the conduction bands and even induce band inversion. Beyond conventional approaches, our finding of tuning the orbital level may greatly expand the range of topologically nontrivial materials

    New insights from GWAS for the cleft palate among han Chinese population

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    Genome wide association studies (GWAS) already have identified tens of susceptible loci for nonsyndromic cleft lip with or without cleft palate (NSCL/P). However, whether these loci associated with nonsyndromic cleft palate only (NSCPO) remains unknown. In this study, we replicated 38 SNPs (Single nucleotide polymorphisms) which has the most significant p values in published GWASs, genotyping by using SNPscan among 144 NSCPO trios from Western Han Chinese. We performed the transmission disequilibrium test (TDT) on individual SNPs and gene-gene (GxG) interaction analyses on the family data; Parent-of-Origin effects were assessed by separately considering transmissions from heterozygous fathers versus heterozygous mothers to affected offspring. Allelic TDT results showed that T allele at rs742071 (PAX7) (p=0.025, ORtransmission=3.00, 95%CI: 1.09-8.25) and G allele at rs2485893 (10kb 3? of SYT14) were associated with NSCPO (p=0.0036, ORtransmission= 0.60, 95%CI: 0.42-0.85). Genotypic TDT based on 3 pseudo controls further confirmed that rs742071 (p-value=0.03, ORtransmission=3.00, 95%CI: 1.09-8.25) and rs2485893 were associated with NSCPO under additive model (p-value= 0.02, ORtransmission= 0.66, 95%CI: 0.47-0.92). Genotypic TDT for epistatic interactions showed that rs4844913 (37kb 3? of DIEXF) interacted with rs11119388 (SYT14) (p-value=1.80E-08) and rs6072081 (53kb 3? of MAFB) interacted with rs6102085 (33kb 3? of MAFB) (p-value=3.60E-04) for NSCPO, suggesting they may act in the same pathway in the etiology of NSCPO. In this study, we found that rs742071 and rs2485893 were associated NSCPO from Han Chinese population; also, interactions of rs4844913:rs11119388 and rs6072081:rs6102085 for NSCPO were identified, gene-gene interactions have been proposed as a potential source of the remaining heritability, these findings provided new insights of the previous GWAS

    Numerical Analysis of Stress Intensity Factors of a Crack in the Composite Patch Repair

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    The composite patch repair technology can be utilized to provide upgrades, such as higher design requirements and life extensions. However, in this case, failures easily happen on the edge interface between the substrate material and the restorative material, because of the incompatible of different properties. Failures such as flaws or cracks lying along the interface reduce the strength of the structure significantly. In this paper, the numerical solutions of hypersingular integro-differential equations are discussed in the analysis of three dimensional interfacial cracks subjected to general internal pressure,and the problem is formulated on the basis of the body force method.The stress intensity factors are given with varying material combinations. It is found that the stress intensity factors and are determined by the bi-materials constant alone, independent of elastic modulus ratio and Poisson\u27s ratio.25th International Ocean and Polar Engineering Conference (ISOPE-2015), Kona, Big Island, Hawaii, USA, June 21-26, 201

    Study on failure warning of tool magazine and automatic tool changer

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    Tool magazine and automatic tool changer (ATC) is used to store and change tools in a machining center, which plays an important role in automatic manufacturing. Therefore, the stability and reliability of tool magazine and ATC is very important to a machining center. Failures of tool magazine and ATC would increase ramp-up repair time and repair cost. So early warning system of failures for tool magazine and ATC becomes a research hotspot. The main vibration signals of tool magazine and ATC would occur obviously when the tool arm grasps a tool holder, draws a tool holder out of a tool into spindle or tool pocket and inserts a tool holder into spindle or tool pocket. To predict failures of tool magazine and ATC and improve the availability of machining center, a vibration test procedure and calculation method of vibration signal threshold of pull nails looseness which can lead to tool falling failures are proposed based on the vibration detection theory. Then, the vibration signals of tool changing are analyzed and the relationship between the maximum amplitude of vibration signals and the looseness severity of pull nails is also illustrated. The final experiment results show that the tool falling failure warning method is feasible to reduce the failures of tool magazine and ATC through the early warning system based on the threshold of vibration signals

    Higher dietary diversity scores and protein-rich food consumption were associated with lower risk of all-cause mortality in the oldest old

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    Background & aims: Dietary diversity is widely advocated in national and international recommendations although whether the beneficial effects on survival or longevity still apply in the final phase of the lifespan remains understudied. We aimed to prospectively examine the association of dietary diversity, food items with all-cause mortality among the oldest old (80+) and determine whether dietary diversity recommendations were appropriate for this population. Methods: The study included 28,790 participants aged 80+ (9957 octogenarians, 9925 nonagenarians, and 8908 centenarians). A baseline dietary diversity score (DDS) was constructed based on nine food items of a food frequency questionnaire. Cox models with penalized splines evaluated non-linear associations of DDS as continuous variable with mortality to identify cut-offs of DDS. Results: We documented 23,503 deaths during 96,739 person-years of follow-up. Each one unit increase in DDS was associated with a 9% lower risk of mortality (adjusted hazard ratio (HR): 0.91; 95% confidential interval (CI): 0.90–0.92). Compared to participants whose DDS less than 2 scores, those with a DDS of 2, 3, 4, 5, and higher than 6 scores had a lower mortality risk, the HRs were 0.86 (0.82–0.89), 0.78 (0.75–0.81), 0.69 (0.66–0.72), 0.65 (0.62–0.68), and 0.56 (0.53–0.58) respectively, and a significant trend emerged (p \u3c 0.001). Protein-rich food items were associated with prominent beneficial effects on mortality including meat (HR and 95% CI for high vs low frequency: 0.70 (0.68–0.72)), fish and sea food (HR, 0.74 (0.72–0.77)), egg (HR, 0.75 (0.73–0.77)), and bean (HR, 0.80 (0.78–0.82)). Conclusions: Even after the age of 80, the DDS tool may offer a simple and straightforward mean of identifying and screening individuals at high risk for mortality. Recommendation of dietary diversity, especially consumption of protein-rich food, may be advocated to reduce mortality risk and promote longevity in the oldest old
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