Study of the Band-gap Structure of a 1D-photonic Crystal by Using Different Numerical Approaches

Liang-Yao Chen,Jian-Bo Chen,Yue-Rui Chen,Yan Shen,Wei-Xi Zhou,Jiu-Chun Ren,Yu-Xiang Zheng 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.4

Comparative studies between the transfer matrices method (TMM) and plane wave method (PWM) approaches have been performed on 1D photonics crystal under different conditions to show the differences between these two kinds of calculations. TMM is suitable for the design of 1D photonic crystal device with high precision and is in good agreement with experimental results, but is not suitable for the 2D and 3D photonic structures which are limited by the complicated boundary conditions at micro interfaces. The result based on the PWM approach to deal approximately with the photonic structure in approximation has not yet been strictly verified by experiment, not even for 1D photonic crystal structures. More efforts will be required to explore its validation under all physical conditions to enhance its application.

Emerging nanoparticulate drug delivery systems of metformin

Yao Chen,Xinzhu Shan,Cong Luo,Zhonggui He 한국약제학회 2020 Journal of Pharmaceutical Investigation Vol.50 No.3

Background Driving the conventional drug in new applications has emerged as a research hotspot for disease treatment. Metformin (MET) is conventionally used for the treatment of type II diabetes. It has also been found to be a versatile molecule with wide biological functions, such as losing weight. anti-aging and anticancer activity. Rational design of nanoparticulate drug delivery systems (nano-DDS) could significantly improve drug delivery efficiency. Recently, a wide range of nano- DDS has been developed to improve the delivery efficacy of MET or to perform as versatile nanoplatforms for efficient drug delivery. Area covered In this review, we outline the emerging trends in advanced nano-DDS of MET, focusing on nano-DDS of MET for diabetes therapy, nano-DDS of MET for anticancer therapeutics, and nano-DDS of MET for other therapeutic aims. Expert opinion Despite the great progression in nano-DDS of MET, there’s still a long way to truly put the conventional drug in new applications. Several important issues should be fully taken into consideration, such the manufacturing cost and economic burdens for patients, the biocompatibility and long-term toxicity of carrier materials, scale-up preparation difficulties, as well as the species gap between human beings and animal models.

Helicobacter pylori Infection and the Risk of Colorectal Adenoma and Adenocarcinoma: an Updated Meta-analysis of Different Testing Methods

Chen, Yao-Sheng,Xu, Song-Xin,Ding, Yan-Bing,Huang, Xin-En,Deng, Bin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Background and Aims: Helicobacter pylori infection may be associated with an increased risk of colorectal carcinoma. However, as most studies on this subject were relatively small in size and differed at least partially in their designs, their results remain controversial. In this study, we aimed to carry out a meta-analysis to evaluate the potential association of H. pylori infection with colorectal adenoma and adenocarcinoma risk, covering all of the different testing methods. Methods: We conducted a search in PubMed, Medline, EBSCO, High Wire Press, OVID, and EMBASE covering all published papers up to March 2013. According to the established inclusion criteria, essential data were then extracted from the included studies and further analyzed by a systematic meta-analysis. Odds ratios were employed to evaluate the relationship between H. pylori infection and the risk of colorectal neoplasms. Results: Twenty-two studies were included, and the odds ratio for the association between H. pylori infection and colorectal cancer was 1.49 (95% confidence interval 1.30-1.72). No statistically significant heterogeneity was observed. Publication bias was ruled out. Conclusion: The pooled data suggest H. pylori infection indeed increases the risk of colorectal adenoma and adenocarcinoma.

Intelligent computational design of scalene-faceted flat-foldable tessellations

Chen Yao,Lu Chenhao,Yan Jiayi,Feng Jian,Sareh Pooya 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.5

Origami tessellations can be folded from a given planar pattern into a three-dimensional object with specific geometric properties, inspiring developments in various fields of science and engineering such as deployable structures, energy absorption devices, reconfigurable robots, and metamaterials. However, the range of existing origami patterns with functional properties such as flat-foldability is rather scant, as analytical solutions to constraint equations arising in the design process are generally highly complicated. In this paper, we tackle the challenging problem of automated design of scalene-faceted flat-foldable origami tessellations using an efficient metaheuristic algorithm. To this end, this study establishes constraint curves based on compatibility conditions for all six-fold (i.e., degree-6) vertices. Subsequently, a graphical method and a particle swarm optimization (PSO) method are adopted to produce optimal origami patterns. Moreover, mountain-valley assignments for the obtained geometric designs are determined using a computational approach based on mixed-integer linear programming. It turns out that the flat-foldable internal vertices of each C2-symmetric unit fragment (UF) exist as C2-symmetric pairs about the centroid of the UF. Furthermore, numerical experiments are carried out to examine the feasibility and compare the accuracy, computational efficiency, and global convergence of the proposed methods. The results of numerical experiments demonstrated that, in comparison with the graphical method, the proposed PSO method has not only a higher accuracy but also a significantly lower computational cost, enabling us to develop an intelligent computational platform to efficiently design scalene-faceted flat-foldable origami tessellations.

Trade Policies and Outsourcing for Market Dominance

( Yao Tung Chen ) 세종대학교 경제통합연구소 (구 세종대학교 국제경제연구소) 2007 Journal of Economic Integration Vol.22 No.2

This paper attempts to analyze the effect of trade policies on the prices of both final and intermediate goods, when outsourcing part of production is a means used to obtain the market dominance in the host country. The market dominance could be granted by the host country to a foreign firm as a reward for its transferring of technology through outsourcing. It is found that when the subsidy by the host country on the production of intermediate inputs is substantial and if the demand curve is concave, a reduction in tariff on the final goods would lead to a rise in the price of both the final and intermediate goods. Consequently, this produces an anti-competitive result.

Elevated thyroid hormones caused by high concentrate diets participate in hepatic metabolic disorders in dairy cows

Chen Qu,Wu Chen,Yao Zhihao,Cai Liuping,Ni Yingdong,Mao Shengyong 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.8

Objective: High concentrate diets are widely used to satisfy high-yielding dairy cows; however, long-term feeding of high concentrate diets can cause subacute ruminal acidosis (SARA). The endocrine disturbance is one of the important reasons for metabolic disorders caused by SARA. However, there is no current report about thyroid hormones involved in liver metabolic disorders induced by a high concentrate diet. Methods: In this study, 12 mid-lactating dairy cows were randomly assigned to HC (high concentrate) group (60% concentrate of dry matter, n = 6) and LC (low concentrate) group (40% concentrate of dry matter, n = 6). All cows were slaughtered on the 21st day, and the samples of blood and liver were collected to analyze the blood biochemistry, histological changes, thyroid hormones, and the expression of genes and proteins. Results: Compared with LC group, HC group showed decreased serum triglyceride, free fatty acid, total cholesterol, low-density lipoprotein cholesterol, increased hepatic glycogen, and glucose. For glucose metabolism, the gene and protein expression of glucose-6- phosphatase and phosphoenolpyruvate carboxykinase 1 in the liver were significantly up-regulated in HC group. For lipid metabolism, the expression of sterol regulatory element-binding protein 1, long-chain acyl-CoA synthetase 1, and fatty acid synthase in the liver was decreased in HC group, whereas carnitine palmitoyltransferase 1α and peroxisome proliferator activated receptor α were increased. Serum triiodothyronine, thyroxin, free triiodothyronine (FT3), and hepatic FT3 increased in HC group, accompanied by increased expression of thyroid hormone receptor (THR) in the liver. Conclusion: Taken together, thyroid hormones may increase hepatic gluconeogenesis, β-oxidation and reduce fatty acid synthesis through the THR pathway to participate in the metabolic disorders caused by a high concentrate diet. Objective: High concentrate diets are widely used to satisfy high-yielding dairy cows; however, long-term feeding of high concentrate diets can cause subacute ruminal acidosis (SARA). The endocrine disturbance is one of the important reasons for metabolic disorders caused by SARA. However, there is no current report about thyroid hormones involved in liver metabolic disorders induced by a high concentrate diet.Methods: In this study, 12 mid-lactating dairy cows were randomly assigned to HC (high concentrate) group (60% concentrate of dry matter, n = 6) and LC (low concentrate) group (40% concentrate of dry matter, n = 6). All cows were slaughtered on the 21st day, and the samples of blood and liver were collected to analyze the blood biochemistry, histological changes, thyroid hormones, and the expression of genes and proteins.Results: Compared with LC group, HC group showed decreased serum triglyceride, free fatty acid, total cholesterol, low-density lipoprotein cholesterol, increased hepatic glycogen, and glucose. For glucose metabolism, the gene and protein expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the liver were significantly up-regulated in HC group. For lipid metabolism, the expression of sterol regulatory element-binding protein 1, long-chain acyl-CoA synthetase 1, and fatty acid synthase in the liver was decreased in HC group, whereas carnitine palmitoyltransferase 1α and peroxisome proliferator activated receptor α were increased. Serum triiodothyronine, thyroxin, free triiodothyronine (FT3), and hepatic FT3 increased in HC group, accompanied by increased expression of thyroid hormone receptor (THR) in the liver.Conclusion: Taken together, thyroid hormones may increase hepatic gluconeogenesis, β-oxidation and reduce fatty acid synthesis through the THR pathway to participate in the metabolic disorders caused by a high concentrate diet.

Large local lattice expansion in graphene adlayers grown on copper

Chen, Chaoyu,Avila, José,Arezki, Hakim,Nguyen, Van Luan,Shen, Jiahong,Mucha-Kruczyń,ski, Marcin,Yao, Fei,Boutchich, Mohamed,Chen, Yue,Lee, Young Hee,Asensio, Maria C. Nature Publishing Group UK 2018 NATURE MATERIALS Vol.17 No.5

<P>Variations of the lattice parameter can significantly change the properties of a material, and, in particular, its electronic behaviour. In the case of graphene, however, variations of the lattice constant with respect to graphite have been limited to less than 2.5% due to its well-established high in-plane stiffness. Here, through systematic electronic and lattice structure studies, we report regions where the lattice constant of graphene monolayers grown on copper by chemical vapour deposition increases up to similar to 7.5% of its relaxed value. Density functional theory calculations confirm that this expanded phase is energetically metastable and driven by the enhanced interaction between the substrate and the graphene adlayer. We also prove that this phase possesses distinctive chemical and electronic properties. The inherent phase complexity of graphene grown on copper foils revealed in this study may inspire the investigation of possible metastable phases in other seemingly simple heterostructure systems.</P>

Graphite-based selectorless RRAM: improvable intrinsic nonlinearity for array applications

Chen, Ying-Chen,Hu, Szu-Tung,Lin, Chih-Yang,Fowler, Burt,Huang, Hui-Chun,Lin, Chao-Cheng,Kim, Sungjun,Chang, Yao-Feng,Lee, Jack C. The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.33

<P>Selectorless graphite-based resistive random-access memory (RRAM) has been demonstrated by utilizing the intrinsic nonlinear resistive switching (RS) characteristics, without an additional selector or transistor for low-power RRAM array application. The low effective dielectric constant value (<I>k</I>) layer of graphite or graphite oxide is utilized, which is beneficial in suppressing sneak-path currents in the crossbar RRAM array. The tail-bits with low nonlinearity can be manipulated by the positive voltage pulse, which in turn can alleviate variability and reliability issues. Our results provide additional insights for built-in nonlinearity in 1<I>R</I>-only selectorless RRAMs, which are applicable to the low-power memory array, ultrahigh density storage, and in-memory neuromorphic computational configurations.</P>

Mediation analysis of leisure activities on the association between cognitive function and mortality: longitudinal study of 42,942 Chinese adults 65 years and older

Chen Xingxing,Zhang Xian,Long Tingxi,Wu Wenfan,Hu Rundong,Jin Xurui,Yan Lijing L,Yao Yao,Wenyu Zhu 한국역학회 2022 Epidemiology and Health Vol.44 No.-

OBJECTIVES: Previous studies have established associations of cognitive function and leisure activities with mortality. This study aimed to evaluate whether leisure activities causally mediate these associations. METHODS: This longitudinal study included 42,246 participants aged over 65 years from the Chinese Longitudinal Healthy Longevity Survey. The Mini-Mental State Examination and a self-reported scale were used to measure cognitive status and leisure activities, respectively. We examined the associations of cognitive function and leisure activities with mortality using Cox proportional hazards models. Causal mediation analysis was used to assess whether leisure activities mediated the association between cognitive function and mortality. RESULTS: Cognitive function and leisure activities were inversely associated with mortality. Leisure activities accounted for 28.3% (95% confidence interval [CI], 25.6 to 31.1) of the total effect (TE) of cognitive function and mortality. A higher mediated proportion (PM) was observed for physical leisure activities (PM, 20.1%; 95% CI, 18.0 to 22.3) than for social leisure activities (PM, 17.7%; 95% CI, 15.7 to 19.7). The mediating effect was higher among participants at younger ages (PM, 41.5%; 95% CI, 21.3 to 65.4), those with higher education levels (PM, 30.5%; 95% CI, 25.3 to 36.2), and residents of rural China (PM, 42.5%; 95% CI, 25.4 to 62.5). CONCLUSIONS: Cognitive function was associated with inverse mortality. Leisure activities significantly mediated this association. Participation in leisure activities at the early stages of mild cognitive impairment could reduce the risk of mortality, which has a major impact on interventional strategies for healthy aging.

Colorectal Cancer Screening in High-risk Populations: a Survey of Cognition among Medical Professionals in Jiangsu, China

Chen, Yao-Sheng,Xu, Song-Xin,Ding, Yan-Bing,Huang, Xin-En,Deng, Bin,Gao, Xue-Feng,Wu, Da-Cheng Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.11

To investigate the cognition of medical professionals when following screening guidelines for colorectal cancer (CRC) and barriers to CRC screening. Between February 2012 and December 2012, an anonymous survey with 19-questions based on several CRC screening guidelines was randomly administered to gastroenterologists, oncologists, general surgeons, and general practitioners in Jiangsu, a developed area in China where the incidence of CRC is relatively high. The average cognitive score was 26.4% among 924 respondents. Gastroenterologists and oncologists had higher scores compared with others (p<0.01 and p<0.01, respectively); doctor of medicine (M.D.) with or without doctor of philosophy (Ph.D.) or holders with bachelor of medical science (BMS) achieved higher scores than other lower degree holders (P<0.05). More importantly, doctors who finished CRC related education in the past year achieved higher scores than the others (p<0.001). The most commonly listed barriers to referring high-risk patients for CRC screening were "anxiety about colonoscopy without anesthesia", "lack of awareness of the current guidelines" and "lack of insurance reimbursement". Lack of cognition was detected among doctors when following CRC screening guidelines for high-risk populations. Educational programs should be recommended to improve their cognition and reduce barriers to CRC screening.