154 results on '"Xuan Chen"'
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2. Lp-theory of linear canonical transforms and related uncertainty principles.
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Xuan Chen, Pei Dang, and Weixiong Mai
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HEISENBERG uncertainty principle , *BANACH algebras , *ADDITIVES - Abstract
In this paper, we revisit some fundamental properties of linear canonical transform (abbreviated as LCT). In particular, we prove the additive property rigorously for LCT in the higher dimensional case (abbreviated as MLCT). We also consider the Lp-theory of MLCT with 1 ≤ p ≤ 2. Specifically, the inversion theorem of MLCT by the related Gauss and Abel means is studied, and the pointwise convergence of approximate identities with respect to convolution for MLCT is also obtained. As applications, we study the Lp-type Heisenberg-Pauli-Weyl uncertainty principles and the Lp-type Donoho-Stark uncertainty principles for MLCT. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Reservoir characteristics and controlling factor of tight sandstone in Shuixigou Group in Taibei depression, Turpan-Hami basin.
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Tong Lin, Xuan Chen, Fan Yang, Hongguang Gou, Mingyu Liu, and Runze Yang
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RESERVOIRS , *SANDSTONE , *ORGANIC acids , *NUCLEAR magnetic resonance , *PARTICLE size distribution - Abstract
The positive structure belts surrounding the Taibei Sag, Turpan-Hami Basin, have been the main targets for oil and gas exploration for years and are now left with remaining resources scattering in reservoirs adjacent to source rocks in the sag, where the Shuixigou Group with substantial oil and gas potential constitutes the primary focus for near-source exploration. Consequently, characterization of development and key controlling factors of reservoir space becomes a must for future exploration in the area. This study investigates the development traits, genesis, and controlling factors of the Xishanyao and Sangonghe formations in the Shengbei and Qiudong Sub-sags of the Taibei Sag with techniques such as cast thin-section observation, porosity and permeability tests, high-pressure mercury injection, and saturation fluid NMR analysis of reservoir rocks. The findings reveal that the Shuixigou Group in the Taibei Sag consists of lithic sandstone. Reservoirs in the group are mostly poor in terms of physical properties, with undeveloped primary pores dominated by intergranular dissolved pores as a result of a strong compaction. Comparative analysis of key controlling factors of the Sangonghe Formation reveals significant distinctions in sandstone particle size, sand body thickness, genesis and distribution, provenance location, and source rock type between the Qiudong area and Shengbei area. Vertically, the coal seams of the Xishanyao Formation exhibit heightened development with shallower burial depth and lower maturity compared to those of the Sangonghe Formation. Consequently, this environment fosters the formation of organic acids, which have a stronger dissolution effect on minerals to develop secondary dissolution pores, and ultimately resulting in better reservoir physical properties. Overall, the reservoirs within the Qiudong area of the Taibei Sag demonstrate superior characteristics compared to those in the Shengbei area. Furthermore, the reservoir physical properties of the Xishanyao Formation are better than those of the Sangonghe Formation. The research findings will provide valuable guidance for the exploration and development of lithological oil and gas reservoirs within the Taibei Sag. [ABSTRACT FROM AUTHOR]
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- 2024
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4. The roles of anti-Müllerian hormone in breast cancer.
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Xuan Chen, Sixuan Liu, Xue Peng, and Xiangyun Zong
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ANTI-Mullerian hormone , *BREAST cancer , *OVARIAN reserve , *GRANULOSA cells , *HORMONE receptors , *AMENORRHEA , *OVARIAN cancer - Abstract
Anti-Müllerian hormone (AMH) is produced and secreted by granulosa cells of growing follicles, and its main role is to inhibit the recruitment of primordial follicles, reduce the sensitivity of follicles to follicle-stimulating hormone (FSH), and regulate FSH-dependent preantral follicle growth. It has become an effective indicator of ovarian reserve in clinical practice. Research on AMH and its receptors in recent years has led to a better understanding of its role in breast cancer. AMH specifically binds to anti-Müllerian hormone receptor II (AMHRII) to activate downstream pathways and regulate gene transcription. Since AMHRII is expressed in breast cancer cells and triggers apoptosis, AMH/AMHRII may play an important role in the occurrence, treatment, and prognosis of breast cancer, which needs further research. The AMH level is a potent predictor of ovarian function after chemotherapy in premenopausal breast cancer patients older than 35 years, either for ovarian function injury or ovarian function recovery. Moreover, AMHRII has the potential to be a new marker for the molecular typing of breast cancer and a new target for breast cancer treatment, which may be a link in the downstream pathway after TP53 mutation. [ABSTRACT FROM AUTHOR]
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- 2023
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5. Enlightening Visualizations of Partially Filled Dielectric Capacitors.
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Xuan, Chen
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CAPACITORS , *DIELECTRICS , *SURFACE charges , *FORCE & energy , *DATA visualization - Abstract
Capacitors with dielectric in series Before discussing capacitors with dielectric in series, it is necessary to consider a triple conductor-plate model, shown in Fig. This paper offers a technique for abstracting capacitors partially filled with a dielectric into parallel and series capacitor models with enlightening visualization approaches. Capacitors with dielectric in parallel Although not directly taught in most textbooks, capacitors partially filled with a dielectric almost always appear as exercise problems in textbooks. [Extracted from the article]
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- 2023
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6. Potential Mechanisms of Yiqi Jiedu Huayu Decoction in the Treatment of Diabetic Microvascular Complications Based on Network Analysis, Molecular Docking, and Experimental Validation.
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Xuan, Chen, Ding, Weisen, Zhan, Ling, Xiong, Yanying, Yu, Xiao, Cao, Wenfu, and Luo, Yan
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DIABETES complications , *BIOLOGICAL models , *HERBAL medicine , *ANIMAL experimentation , *APOPTOSIS , *RATS , *OXIDATIVE stress , *TRANSFERASES , *RESEARCH funding , *COMPUTER-assisted molecular modeling , *PHARMACEUTICAL chemistry , *MOLECULAR structure , *CHINESE medicine , *DIABETIC angiopathies , *THERAPEUTICS - Abstract
Background. Diabetic microvascular complications are the main causes of organ dysfunction and even death in diabetic patients. Our previous studies confirmed the beneficial effects of Yiqi Jiedu Huayu Decoction (YJHD) on diabetic cardiomyopathy and diabetic nephropathy. It is not clear whether YJHD can treat multiple diabetic microvascular complications including diabetic retinopathy, diabetic cardiomyopathy, and diabetic nephropathy through some common mechanisms. Methods. TCMSP, SymMap, STITCH, Swiss Target Prediction, and SEA databases were used to collect and analyze the components and targets of YJHD. GeneCards, DrugBank, DisGeNET, OMIM, and GEO databases were used to obtain target genes for diabetic retinopathy, diabetic cardiomyopathy, and diabetic nephropathy. The GO and KEGG enrichment analyses were performed on the DAVID and STRING platforms. Molecular docking was used to evaluate the binding sites and affinities of compounds and target proteins. Animal experiments were designed to validate the network pharmacology results. Results. Through network pharmacological analysis, oxidative stress, inflammatory response, and apoptosis were identified as key pathological phenotypes for the treatment of diabetic microvascular complications with YJHD. In addition, JNK, p38, and ERK1/2 were predicted as key targets of YJHD in regulating the abovementioned pathological phenotypes. The results of animal experiments showed that YJHD could ameliorate retinal pathological changes of diabetes rats. YJHD can inhibit oxidative stress and inflammation in heart and kidney of diabetic rats. Molecular docking showed strong binding between compounds and JNK, p38, and ERK1/2. Berlambine may play a key role in the treatment process and is considered as a promising regulator of MAPK protein family. The regulatory effects of YJHD on JNK, p38, and ERK1/2 were demonstrated in animal experiments. Conclusions. YJHD may play a therapeutic role in diabetic microvascular complications by regulating oxidative stress, inflammatory response, and apoptosis. The regulation of JNK, p38, and ERK1/2 phosphorylation may be the key to its therapeutic effect. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Communal Narcissism and Sadism as Predictors of Everyday Vigilantism.
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Fan Xuan Chen, Ok, Ekin, and Aquino, Karl
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VIGILANCE committees , *NARCISSISM , *SADISM , *SOCIAL norms , *SELF-perception - Abstract
Vigilantes monitor their social environment for signs of wrongdoing and administer unauthorized punishment on those who they perceive to be violating laws, social norms, or moral standards. We investigated whether the willingness to become a vigilante can be predicted by grandiose selfperceptions about one's communality (communal narcissism) and enjoyment of cruelty (sadism). As hypothesized, findings demonstrated both variables to be positively related to becoming a vigilante as measured by reports of past and anticipated vigilante behavior (Study 1) and by dispositional tendencies toward vigilantism (Studies 1 and 2). We also found communal narcissism and sadism predicted the perceived effectiveness of vigilante actions exhibited by others (Study 2) and the intention to engage in vigilantism after witnessing a norm violation (Study 3). Finally, Study 3 also demonstrated that the tendency for communal narcissists and sadists to become a vigilante might vary based on the expected consequences of the observed norm violation. [ABSTRACT FROM AUTHOR]
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- 2023
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8. MiR-493-5p alleviates lipopolysaccharide-induced inflammation in ATDC5 chondrogenic cells by targeting TAB2.
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Xuan Chen, De Li, and Mangmang Chen
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GENE expression , *GENETIC overexpression , *PROTEIN expression , *CELL survival , *INFLAMMATION , *CARTILAGE cells - Abstract
Purpose: To investigate the effect of miR-493-5p in lipopolysaccharide (LPS) -induced ATDC5 chondrogenic cells. Methods: The MTT assay was used to determine the viability of LPS-induced ATDC5 cells. ENCORI (starbase.sysu.edu.cn/) was used to predict the target of miR-493-5p. Quantitative reverse-transcriptionpolymerase chain reaction (qRT-PCR) was used to determine miR-493-5p expression in ATDC5 controlled cells and cells treated with various combinations of LPS, negative control miRNA (NC), miR493-5p mimic, TAB2 overexpression vector, and miR-493-5p inhibitor. qRT-PCR, while western blot was used to assess TAB2 mRNA and protein expression levels in control, LPS, LPS + NC, LPS + miR493-5p mimic, and LPS + miR-493-5p inhibitor groups. The qRT-PCR and ELISA were used to evaluate TNF-α, IL-18, and IL-1β expressions in control, NC, LPS, LPS + NC, miR-493-5p mimic, and LPS + miR-493-5p mimic. Furthermore, the two techniques were also used determine LPS + miR-493-5p inhibitor, LPS + TAB2 overexpression, and LPS + TAB2 overexpression + miR-493-5p mimic groups. Results: MiR-493-5p expression was downregulated in LPS-induced ATDC5 cells (p < 0.001). Overexpression of miR-493-5p increased LPS-induced ATDC5 cell viability but decreased expression of inflammatory factors (p < 0.001). MiR-493-5p targeted and inhibited TAB2 expression in LPS-induced ATDC5 cells (p < 0.001). TAB2 overexpression reversed the suppression of TAB2 by miR-493-5p in LPS-induced ATDC5 cell injury (p < 0.001). Conclusion: MiR-493-5p alleviates LPS-induced inflammation of ATDC5 chondrogenic cells by targeting TAB2. Thus, miR-493-5p and TAB2 have potentials for use as clinical therapeutic targets for OA. [ABSTRACT FROM AUTHOR]
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- 2022
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9. Network Pharmacology and In Vivo Analysis of Dahuang-Huangqi Decoction Effectiveness in Alleviating Renal Interstitial Fibrosis.
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Luo, Yan, Xuan, Chen, Cheng, Junxiong, Xiong, Yu, and Cao, Wenfu
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PROTEIN metabolism , *INTERLEUKINS , *GLOMERULAR filtration rate , *PROTEIN kinases , *HERBAL medicine , *IN vivo studies , *BLOOD urea nitrogen , *NITRIC-oxide synthases , *ANIMAL experimentation , *WESTERN immunoblotting , *FIBROSIS , *MICRORNA , *HYPERPLASIA , *KIDNEY diseases , *RATS , *CELLULAR signal transduction , *PHARMACEUTICAL chemistry , *POLYMERASE chain reaction , *VASCULAR endothelial growth factors , *CHINESE medicine , *CREATININE , *NECROSIS , *TOLL-like receptors ,URETHRAL obstruction - Abstract
Dahuang and Huangqi are the most frequently prescribed treatment methods for chronic kidney disease in China. Our study aimed to clarify the pharmacological mechanism of action of Dahuang-Huangqi decoction (DHHQD) in renal interstitial fibrosis (RIF). The intersection of genes targeted by DHHQD active ingredients and RIF target genes was searched using network pharmacology to build a chemical ingredient and disease target network. For in vivo analysis, Sprague–Dawley rats with unilateral urethral obstruction (UUO) were administered DHHQD, and their kidney function-related indicators and pathological indices were determined. The expression of core targets was quantified using real-time polymerase chain reaction and western blotting. A total of 139 common targets for DHHQD and RIF in chronic kidney disease were detected. Compared with the untreated UUO rats, the DHHQD-treated rats showed reductions in the following: blood urea nitrogen and serum creatinine levels, kidney tubular atrophy and necrosis, interstitial fibrosis, hyperplasia and abnormal deposition of extracellular matrix, and microstructural changes in the mesangial matrix and glomerular basement membrane. DHHQD treatment significantly regulated the levels of renal core proteins, such as eNOS, IL-6, EGFR, and VEGF and reduced the mRNA and protein expression of the core targets involved in inflammation pathways, such as PI3K/AKT and TLR4/NF-κB. DHHQD treatment ameliorated the severity of RIF by potentially regulating the AKT/PI3K and TLR4/NF-κB signaling pathways. Our study findings provide insights into the mechanisms associated with DHHQD action and essential data for future research. [ABSTRACT FROM AUTHOR]
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- 2022
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10. Network Pharmacology and In Vivo Analysis of Dahuang-Huangqi Decoction Effectiveness in Alleviating Renal Interstitial Fibrosis.
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Luo, Yan, Xuan, Chen, Cheng, Junxiong, Xiong, Yu, and Cao, Wenfu
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INTERLEUKINS , *HERBAL medicine , *IN vivo studies , *BLOOD urea nitrogen , *ANIMAL experimentation , *WESTERN immunoblotting , *EPIDERMAL growth factor , *FIBROSIS , *KIDNEY diseases , *TREATMENT effectiveness , *RATS , *GENE expression , *GENES , *MESSENGER RNA , *PHARMACEUTICAL chemistry , *VASCULAR endothelial growth factors , *CHINESE medicine , *CREATININE , *NECROSIS - Abstract
Dahuang and Huangqi are the most frequently prescribed treatment methods for chronic kidney disease in China. Our study aimed to clarify the pharmacological mechanism of action of Dahuang-Huangqi decoction (DHHQD) in renal interstitial fibrosis (RIF). The intersection of genes targeted by DHHQD active ingredients and RIF target genes was searched using network pharmacology to build a chemical ingredient and disease target network. For in vivo analysis, Sprague–Dawley rats with unilateral urethral obstruction (UUO) were administered DHHQD, and their kidney function-related indicators and pathological indices were determined. The expression of core targets was quantified using real-time polymerase chain reaction and western blotting. A total of 139 common targets for DHHQD and RIF in chronic kidney disease were detected. Compared with the untreated UUO rats, the DHHQD-treated rats showed reductions in the following: blood urea nitrogen and serum creatinine levels, kidney tubular atrophy and necrosis, interstitial fibrosis, hyperplasia and abnormal deposition of extracellular matrix, and microstructural changes in the mesangial matrix and glomerular basement membrane. DHHQD treatment significantly regulated the levels of renal core proteins, such as eNOS, IL-6, EGFR, and VEGF and reduced the mRNA and protein expression of the core targets involved in inflammation pathways, such as PI3K/AKT and TLR4/NF-κB. DHHQD treatment ameliorated the severity of RIF by potentially regulating the AKT/PI3K and TLR4/NF-κB signaling pathways. Our study findings provide insights into the mechanisms associated with DHHQD action and essential data for future research. [ABSTRACT FROM AUTHOR]
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- 2022
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11. Research on the Construction of Evaluation System of College Physical Education Wushu Teaching under Multiple Intelligences Theory.
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Xuan Chen
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PHYSICAL education , *CHINESE martial arts , *COLLEGE physical education teachers , *SPORTS & state , *ATHLETIC clubs , *SPORTS finance - Abstract
In order to better improve the martial arts learning effect, this paper puts forward the design method of martial arts motion feedback system based on target intelligent tracking video processing. It optimizes the hardware configuration of the system, adds a composite tracker to the system, to effectively track the motion changes of different human targets, and further combines the real-time target intelligent tracking video processing technology. Build a moving target tracking model; then, based on the calculation of motion characteristic parameters, CRF method is used for motion behavior recognition and feedback. Measuring the data using smart PLS software and running different results included descriptive statistical analysis, correlation analysis, model fitness analysis, and the smart PLS Algorithm model also describes that graphical analysis related to the variables. It is the expectation of the Chinese Government to achieve urban-rural integration and close the urban-rural divide by lowering health inequities and enhancing social connections at the same time. Given that involvement in sports may provide a variety of physical and mental advantages, as a manner of increasing possibilities for social connections, community provision plays an important part in this regard. The overall results found that there is positive and significant relationships in-between [ABSTRACT FROM AUTHOR]
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- 2022
12. Exploring photo-deformation of polydomain liquid crystal polymers by homogenization.
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Xuan, Chen and Huo, Yongzhong
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OPTICAL polarization , *CRYSTAL orientation , *POLYMER liquid crystals , *COMPOSITE materials , *LIQUID crystals - Abstract
This article explores photo-deformation of polydomain liquid crystal polymers. Photo-isomerization-driven stimuli differ from thermal ones in mechanical response in that domains deform in differing amounts according to their relative alignment with respect to light polarization, by contracting along their liquid crystal orientation by an amount maximized at parallel alignment, and therefore polydomains' response to light is complicated. Theoretical analysis of polydomain deformation with random domain alignments can be greatly simplified by applying homogenization method to obtain effective overall deformation. Not only is polydomain photo deformation very different from monodomain, but domain distributions enable very different photo responses. Anticlastic, syn-clastic and cylindrical-shell bending modes will be predicted, dictated by order parameter and material thickness. This work serves as a guide to theoretical analysis of composite materials with microstructure and to controlling their morphing shapes experimentally. [ABSTRACT FROM AUTHOR]
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- 2020
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13. The geometric, optical, and magnetic properties of the endohedral stannaspherenes M@Sn12 (M=Ti, V, Cr, Mn, Fe, Co, Ni).
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Xuan Chen, Kaiming Deng, Yuzhen Liu, Chunmei Tang, Yongbo Yuan, Weishi Tan, and Xin Wang
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MAGNETIC properties , *TRANSITION metals , *METALS , *ATOMS , *OPTICAL properties , *TUNABLE lasers - Abstract
The geometric, optical, and magnetic properties of the M@Sn12 clusters (M=Ti, V, Cr, Mn, Fe, Co, Ni) are studied using the relativistic density-functional method. The geometric optimization shows that the ground states of these clusters are probably very close to the Ih structure. Our calculations demonstrate that the optical gaps of the M@Sn12 can be tuned from infrared to green, and the magnetic moments of them vary from 2 μB to 5 μB by doping d transition metal atoms into Sn12 cage, suggesting that M@Sn12 could be a new class of potential nanomaterials with tunable magnetic and optical properties. [ABSTRACT FROM AUTHOR]
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- 2008
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14. Evaluating fracture properties of crumb rubber modified asphalt mixes.
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Xuan Chen and Solaimanian, Mansour
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CRUMB rubber , *GIN , *ASPHALT , *ASPHALT modifiers , *PEAK load , *TIRES - Abstract
Discarded vehicle tires pose a severe environmental problem in the United States. Incorporating shredded tire rubber as crumb rubber modifier (CRM) into asphalt paving materials has shown potential for great benefits. This study was undertaken to evaluate the effect of CRM, base virgin binder stiffness, total binder content, and aggregate gradation on fracture performance of CRM asphalt mixes using the semi -circular bend (SCB) fracture test. All mixes were long term oven aged (LTOA) before testing at the effective temperature for cracking resistance. The results were analyzed within the context of several response parameters: a modified version of Illinois flexibility index (FI), fracture energy, and the load at failure (peak load). Fracture performance of virgin and CRM binders were also evaluated using linear amplitude sweep (LAS) test and the Glover-Rowe (G-R) parameter obtained from dynamic shear rheometer (DSR). As expected, adding CRM into asphalt mixes increased the design binder content. In addition, design binder content increased as the CRM content increased in the mix. Fracture test results showed that among dense graded mixes, CRM mixes with the highest binder c ontent showed superior flexibility and cracking resistance compared with those with lower binder content, in spite of the fact that CRM mixes delivered lower peak load (i.e. strength). It was also shown through this study that gap graded CRM mixes are preferred to dense graded CRM mixes as they del iver higher flexibility thus better cracking resistance. Finally, results from the binder tests demonstrated superior cracking resistance of CRM binders compared with vir gin binders. [ABSTRACT FROM AUTHOR]
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- 2019
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15. Striga crispata sp. nov. (Orobanchaceae), a new hemiparasitic species from Taiwan.
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Sheng-Zehn YANG, Zi-Xuan CHEN, Chien-Fan CHEN, and Po-Hao CHEN
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WITCHWEEDS , *PARASITIC plants , *OROBANCHACEAE , *PARASITISM - Abstract
A new hemiparasitic species, Striga crispata sp. nov., is described and illustrated from Tawu Township, Taitung County, Southern Taiwan. It most closely resembles the Australian species, S. parviflora (R. Brown) Benth, but can be differentiated by longer corollas that are pink or pinkish purple in color, corolla-lobes with crispate margins, and ornamented seed surface that is only covered by the primary ridge. A morphological description, line drawings, photographs, and conservation status are provided to aid identification. [ABSTRACT FROM AUTHOR]
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- 2018
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16. SNP rs3202538 in 3'UTR region of ErbB3 regulated by miR-204 and miR-211 promote gastric cancer development in Chinese population.
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Yaxiang Shi, Xuan Chen, Biao Xi, Xiaowen Yu, Jun Ouyang, Chunxia Han, Yucheng Qin, Defeng Wu, and Hong Shen
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ONCOGENES , *METASTASIS , *MICRORNA , *STOMACH cancer , *CELL proliferation , *TUMORS - Abstract
Background/aims: ErbB3 is an oncogene which has proliferation and metastasis promotion effects by several signaling pathways. However, the individual expression difference regulated by miRNA was almost still unknown. We focused on the miRNAs associated SNPs in the 3'-UTR of ErbB3 to investigate the further relationship of the SNPs with miRNAs among Chinese gastric cancer (GC) patients. Methods: We performed case--control study including 851 GC patients and 799 cancer-free controls. Genotyping, real-time PCR assay, cell transfection, the dual luciferase reporter assay, western-blot, cell proliferation and trans-well based cell invasion assay were used to investigate the effects of the SNP on ErbB3 expression. Moreover, a 5-years-overall survival and relapse free survival were investigated between different genotypes. Results: We found that patients suffering from Helicobacter pylori (Hp.) infection indicated to be the susceptible population by comparing with controls. Besides, SNP rs3202538 (G/T) in ErbB3 3'-UTR was involved in the occurrence of GC by acting as tumor risk factors. SNP rs3202538 (G/T) could be regulated by both miR-204 and miR-211 which caused an upregulation of ErbB3 in patients. Furthermore, the carriers of T genotype was related to the signifcantly high expression of ErbB3, and to big tumor size, poor differentiation as well as the high probability of metastasis. Both miR-211 and miR-204 can signifcantly decrease cell proliferation, metastasis as well as downstream AKT activation through G but not T allele of ErbB3 3'UTR. Moreover, the SNP of G/T was associated with shorter survival of post-surgery GC patients with 5 years of follow up study. Conclusion: In conclusion, our findings have shown that the SNP rs3202538 (G/T) in ErbB3 3'-UTR acted as pro- motion factors in the GC development through disrupting the regulatory role of miR-204 and miR-211 in ErbB3 expression. [ABSTRACT FROM AUTHOR]
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- 2017
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17. Continuum mechanical modeling of liquid crystal elastomers as dissipative ordered solids.
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Zhang, Yang, Xuan, Chen, Jiang, Yuefeng, and Huo, Yongzhong
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LIQUID crystals , *ISOKINETIC exercise - Abstract
Highlights • A continuum model is proposed for the unusual mechanical behavior of liquid crystal elastomers based on dissipation principle for viscoelastic solids with micro order. • Contribution of Ericksen–Lesilie stress can make the total Cauchy stress asymmetric and result in a torque to reorient the alignment of liquid crystal. • The balance equations of momentum and micro order can be solved numerically using commercial finite element software without much difficulty. • Numerical solutions confirm the possible appearance of stripe domains and agree quite well with experiments. Abstract Liquid crystal elastomers (LCEs) are special cross-linked polymer materials combining the large elastic deformability of elastomers with the orientational orders of liquid crystals. Here we develop a general framework of LCEs in the language of continuum mechanics to consider the interaction of polymer backbone and Liquid Crystal (LC) microstructure, which is suitable for large deformation and large director rotation. Based on the dissipation principle, the balance of momentum and the evolution equations of orientational order are obtained. In addition to the deformation and its time derivative, the basic kinematic ingredients of this theory are identical to those arising in the director theories and the order tensor theories for nematic fluids. The Cauchy stress consists of not only the bulk stress contribution of the backbone but also the Ericksen–Leslie stress of LC and the obtained rotational momentum balance implies the asymmetric Cauchy stress due to the inhomogeneous director rotation. Based on the principles of objectivity and symmetry, we present the general form of free energy densities and Rayleigh dissipation function and give some possible invariants of constitutive functions. Further, we propose a simple model to study the rate dependence of stretch induced reorientation processes for thin LCE films. Semi-analytical method is utilized to obtain the solutions of constrained uniaxial stretches and stretches with shear for homogenous deformations. The results indicate that the stress-deformation response and the director rotation are rate dependent and can be non-monotonic depending on the initial orientations. Finite element simulations are carried out to study the process of uniaxial stretches with fixed grips. Two different types of stress induced director reorientation processes are observed, one via stripe domains and the other via uniform rotations. We find that the appearance of the stripe domains has a strong dependence on aspect ratios and initial director orientation, which show good agreement with experiment results. [ABSTRACT FROM AUTHOR]
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- 2019
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18. Concurrent reaction and diffusion in photo-responsive hydrogels.
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Xuan, Chen and Jin, Lihua
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PHOTOISOMERIZATION , *DIFFUSION , *HYDROGELS , *CHEMICAL reactions , *SOLVENTS , *POLYMER networks - Abstract
Abstract A hydrogel is a polymer network dispersed in an aqueous solvent. A hydrogel with photo-reactive molecules bonded on the polymer network can change its volume in response to light. The light triggers a chemical reaction of the photo-reactive molecules, for example the photo-isomerization of spirobenzopyran, and alters the interaction parameter between the polymer network and the solvent molecules, which drives the diffusion of the solvent molecules, inducing a volumetric change of the hydrogel. The photo-response kinetics of the hydrogel is governed by concurrent reaction and diffusion. In this paper, we establish a theoretical framework to describe the constitutive behavior of photo-responsive hydrogels based on non-equilibrium thermodynamics. The framework, coupling deformation of hydrogels with diffusion of solvent molecules and reaction of photo-reactive molecules, allows us to predict the spatiotemporal response of photo-responsive hydrogels under light and in the dark. We show the significantly different photo-response kinetics, including reaction-limited, diffusion-limited, and reaction-diffusion coupling processes, with constrained and free swelling of a hydrogel thin film as examples. Particularly, we demonstrate how slow diffusion postpones the onset of post-illumination kinetic response of a photo-responsive hydrogel in the dark. This framework provides us understanding and design guidelines for photo-responsive hydrogels. [ABSTRACT FROM AUTHOR]
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- 2019
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19. General Space-Confined On-Substrate Fabrication of Thickness-Adjustable Hybrid Perovskite Single-Crystalline Thin Films.
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Yao-Xuan Chen, Qian-Qing Ge, Yang Shi, Jie Liu, Ding-Jiang Xue, Jing-Yuan Ma, Jie Ding, Hui-Juan Yan, Jin-Song Hu, and Li-Jun Wan
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PEROVSKITE , *OXIDE minerals , *THIN films , *SURFACE coatings , *MICROMETERS - Abstract
Organic-inorganic hybrid perovskite single-crystalline thin films (SCTFs) are promising for enhancing photoelectric device performance due to high carrier mobility, long diffusion length, and carrier lifetime. However, bulk perovskite single crystals available today are not suitable for practical device application due to the unfavorable thickness. Herein, we report a facile space-confined solution-processed strategy to on-substrate grow various hybrid perovskite SCTFs in a size of submillimeter with adjustable thicknesses from nano- to micrometers. These SCTFs exhibit photoelectric properties comparable to bulk single crystals with low defect density and good air stability. The clear thickness-dependent colors allow fast visual selection of SCTFs with a suitable thickness for specific device application. The present substrate-independent growth of perovskite SCTFs opens up opportunities for on-chip fabrication of diverse high-performance devices. [ABSTRACT FROM AUTHOR]
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- 2016
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20. An Analysis of Operational Efficiency of Agricultural Insurance Agency: Based on Three-Stage DEA Model.
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Xuan CHEN and Wenhuan WEI
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From the perspective of agricultural insurance agency, this paper focuses on the study of operational efficiency of agricultural insurance agency, and analyzes the operational efficiency of agricultural insurance agency and its influencing factors, in order to improve the operational efficiency of agricultural insurance agency, better supply agricultural insurance and achieve the policy effect of agricultural insurancc. The results of this paper are as follows: (i) Either comprehensive operatonal efficiency or scale efficiency of Chinese-funded agency is higher than that of foreign-funded agency, but its pure technical efficiency is lower than that of foreign-funded agency, indicating that the managerial decision ability of Chinese-funded agency is weaker than that of foreign-funded agency, and needs to be improved ; (ii) The operational efficiency of professional agricultural insurance agency is higher than that of comprehensive agricultural insurance agency, and the agricultural insurance agency is greatly Mfected by environmental factors ; () The operating time of agricultural insurance agency is proportional to its operational efficiency; (iv) The quality of employees is positively correlated with the capital and cost input diference, but negatively correlated with the diference in the number of employees. Therefore, it is necessary to pay attention to the improvement of employees' working efficiency while laying emphasis on employees' quality. [ABSTRACT FROM AUTHOR]
- Published
- 2016
21. Clinicopathological role of miR-30a-5p in hepatocellular carcinoma tissues and prediction of its function with bioinformatics analysis.
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Wen-Ting Huang, Zu-xuan Chen, Rong-quan He, Yu-zhuang Wu, Shu-ya Yin, Xiao-na Liang, Gang Chen, Hong Yang, Zhi-gang Peng, and Li-hua Yang
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LIVER cancer , *CARCINOGENESIS , *GENE expression , *MICRORNA , *CLINICAL pathology , *GENETICS - Abstract
Background: It has been reported that deregulation or dysfunction of microRNAs (miRNAs) plays an essential part in the hepatocarcinogenesis. However, the contribution and mechanism of microRNA-30a-5p (miR-30a-5p) in hepatocellular carcinoma (HCC) remains largely unknown. Therefore, our aim was to investigate the clinicopathological role of miR-30a-5p in HCC tissues and explore its potential pathways in this study. Methods: The expression of miR-30a-5p was measured in 95 HCC and adjacent noncancer tissues by real-time reverse transcription quantitative polymerase chain reaction. The relationship between miR-30a-5p expression levels and clinicopathological parameters was also analyzed. Furthermore, the potential target genes of miR-30a-5p were collected via online prediction and literature searching. Gene ontology and pathway enrichment analyses were used to identify the possible function of miR-30a-5p in HCC. Results: Compared with adjacent noncancer tissues (2.23±0.77), expression level of miR-30a-5p was significantly lower in HCC tissues (1.26±0.66, P,0.001). MiR-30a-5p expression was evidently correlated with tumor nodes, metastasis, tumor-node-metastasis stage, portal vein tumor embolus, vascular invasion, and status of tumor capsule (all P,0.05). A total of 878 genes were finally used for the biological informatics analyses. These prospective target genes were highly enriched in various key pathways, for instance, Ubiquitin-mediated proteolysis, Axon guidance, Neurotrophin signaling pathway, Amyotrophic lateral sclerosis, and ErbB signaling pathway. Conclusion: In conclusion, this study clarifies that the downregulation of miRNA-30a-5p might play a vital part in the incidence and progression of HCC via targeting various prospective genes and pathways. Future validation is required to further explore the prospective molecular mechanism of miR-30a-5p in HCC. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
22. Current-driven dynamics of skyrmions in the presence of pinning at finite temperatures.
- Author
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Jiang, Yunxi, Xuan, Chen, and Yu, Hao
- Subjects
- *
SKYRMIONS , *COMPUTER systems , *LOW temperatures , *MAGNETIC materials , *FINITE, The , *FLUX pinning , *PERSONAL identification numbers - Abstract
Magnetic skyrmions are topological solitons in magnetic materials with broken spatial inversion symmetry. They offer potential as an information carrier for future low-power memory and computing systems owing to the small size and relatively low driving current compared to traditional devices. To develop applications such as racetrack memory at ambient temperature, the interaction of current-driven motion, pinning and thermal fluctuations must be investigated. The skyrmion dynamics at finite temperatures are shown using the expanded Thiele equation, and the relationship between critical depinning current and temperature is established with regard to different damping constants. Furthermore, we found that the Thiele equation still is insufficient to describe the dynamics of skyrmion precisely at low temperatures with the presence of pinning. Moreover, we have shown that the skyrmion Hall angle is dependent on the driving current in the presence of the pinning effect at various finite temperatures. • The interplay of pinning centers, thermal fluctuations and skyrmions. • Thermal fluctuations may suppress the pinning effect for some parameters. • Temperature-dependent depinning current varies with damping constants. • Skyrmion Hall angle depends on temperature, damping constant, and pinning. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
23. Molecular characterization of a novel ring 6 chromosome using next generation sequencing.
- Author
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Rui Zhang, Xuan Chen, Peiling Li, Xiumin Lu, Yu Liu, Yan Li, Liang Zhang, Mengnan Xu, and Cram, David S.
- Subjects
- *
CHROMOSOMES , *GENETIC regulation , *KARYOTYPES , *CHROMOSOME abnormalities , *DNA copy number variations - Abstract
Background: Karyotyping is the gold standard cytogenetic method for detection of ring chromosomes. In this study we report the molecular characterization of a novel ring 6 (r6) chromosome in a six-year-old girl with severe mental retardation, congenital heart disease and craniofacial abnormalities. Methods: Cytogenetic analysis was performed by conventional karyotyping. Molecular genetic analyses were performed using high-resolution chromosome microarray analysis (CMA) and next generation sequencing (NGS). OMIM, UCSC and PubMed were used as reference databases to determine potential genotype to phenotype associations. Results: Peripheral blood and skin fibroblast karyotyping revealed the presence of a dominant cell line, 46,XX,(r6)(p25.3;q27) and a minor cell line 45,XX,-6. Molecular karyotyping using NGS identified 6p25.3 and 6q27 subtelomeric deletions of 1.78 Mb and a 0.56 Mb, respectively. Based on the known genes located within the r6 deletion interval 6q25.3-pter, genotype to phenotype association studies found compelling evidence to suggest that hemizygous expression of disease genes FOXC1, FOXF2, IRF4 and GMDS was the main underlying cause of the patient's phenotype. We further speculate that the severity of the patient's symptoms may have been exacerbated by low-level instability of the r6 chromosome. Conclusion: This is the first report of a novel r6 chromosome characterized at the molecular level using NGS. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
24. Multiple bifurcations and local energy minimizers in thermoelastic martensitic transformations.
- Author
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Xuan, Chen, Ding, Shurong, and Huo, Yongzhong
- Abstract
Thermoelastic martensitic transformations in shape memory alloys can be modeled on the basis of nonlinear elastic theory. Microstructures of fine phase mixtures are local energy minimizers of the total energy. Using a one-dimensional effective model, we have shown that such microstructures are inhomogeneous solutions of the nonlinear Euler-Lagrange equation and can appear upon loading or unloading to certain critical conditions, the bifurcation conditions. A hybrid numerical method is utilized to calculate the inhomogeneous solutions with a large number of interfaces. The characteristics of the solutions are clarified by three parameters: the number of interfaces, the interface thickness, and the oscillating amplitude. Approximated analytical expressions are obtained for the interface and inhomogeneity energies through the numerical solutions. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
25. Sp1 and c-Myc modulate drug resistance of leukemia stem cells by regulating survivin expression through the ERK-MSK MAPK signaling pathway.
- Author
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Yi Zhang, Hai-xuan Chen, Shu-yan Zhou, Shao-xiang Wang, Kai Zheng, Dan-dan Xu, Yu-ting Liu, Xiao-yan Wang, Xiao Wang, Hai-zhao Yan, Li Zhang, Qiu-ying Liu, Wan-qun Chen, and Yi-fei Wang
- Subjects
- *
PRELEUKEMIA , *HEMATOLOGIC malignancies , *LEUCOCYTOSIS , *STEM cell culture , *DRUG resistance , *PHARMACOLOGY - Abstract
Background: Acute myeloid leukemia (AML) is initiated and maintained by a subset of self-renewing leukemia stem cells (LSCs), which contribute to the progression, recurrence and therapeutic resistance of leukemia. However, the mechanisms underlying the maintenance of LSCs drug resistance have not been fully defined. In this study, we attempted to elucidate the mechanisms of LSCs drug resistance. Methods: We performed reverse phase protein arrays to analyze the expression of anti-apoptotic proteins in the LSC-enriched leukemia cell line KG-1a. Immuno-blotting, cell viability and clinical AML samples were evaluated to verify the micro-assay results. The characteristics and transcriptional regulation of survivin were analyzed with the relative luciferase reporter assay, mutant constructs, chromatin immuno-precipitation (ChIP), quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR), and western blotting. The levels of Sp1, c-Myc, phospho-extracellular signal-regulated kinase (p-ERK), phospho-mitogen and stress-activated protein kinase (p-MSK) were investigated in paired CD34+ and CD34- AML patient samples. Results: Survivin was highly over-expressed in CD34 + CD38- KG-1a cells and paired CD34+ AML patients compared with their differentiated counterparts. Functionally, survivin contributes to the drug resistance of LSCs, and Sp1 and c-Myc concurrently regulate levels of survivin transcription. Clinically, Sp1 and c-Myc were significantly up-regulated and positively correlated with survivin in CD34+ AML patients. Moreover, Sp1 and c-Myc were further activated by the ERK/MSK mitogen-activated protein kinase (MAPK) signaling pathway, modulating survivin levels. Conclusion: Our findings demonstrated that ERK/MSK/Sp1/c-Myc axis functioned as a critical regulator of survivin expression in LSCs, offering a potential new therapeutic strategy for LSCs therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
26. The synthesis and activities of novel mononuclear or dinuclear cyclen complexes bearing azole pendants as antibacterial and antifungal agents.
- Author
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Shuo Li, Jia-Xuan Chen, Qing-Xiang Xiang, Li-Qun Zhang, Cheng-He Zhou, Jia-Qing Xie, Lan Yu, and Fang-Zhen Li
- Subjects
- *
CYCLENS , *AZOLES , *ANTIBACTERIAL agents , *ANTIFUNGAL agents , *MACROCYCLIC compound synthesis , *NUCLEAR magnetic resonance spectroscopy - Abstract
A series of novel compounds containing 1,4,7,10-tetraazacyclododecane and azoles were synthesized and characterized by ¹H NMR, MS and elemental analysis. Bioactive assay manifested that some target compounds, such as 11a, 11b and 11d, displayed good and broad spectrum antimicrobial activities with relative low MIC values against most of tested strains. These dinuclear complexes gave comparable or even better antimicrobial efficiencies than the reference drugs Fluconazole and Chloromycin. The result showed that the metal ions were the key factors to enhance the antimicrobial activities for mononuclear or dinuclear complexed in varying degrees. The interaction evaluation of compound 11b with bovine serum albumin (BSA) as an example was tested by fluorescence method. The thermodynamic parameters indicated that the hydrogen bonds and van der waals forces played the major roles in the strong association between dinuclear compound and BSA. The CCK-8 tests also confirmed the safeties of these dinuclear compounds in vitro. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
27. Type 2 diabetes mellitus control and atherosclerosis prevention in a non-obese rat model using duodenal-jejunal bypass.
- Author
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XUAN CHEN, ZHEN HUANG, WENHUA RAN, GANG LIAO, LANG ZHA, and ZIWEI WANG
- Subjects
- *
TYPE 2 diabetes prevention , *ATHEROSCLEROSIS prevention , *GASTRIC bypass , *LABORATORY rats , *NF-kappa B , *STREPTOZOTOCIN , *THERAPEUTICS - Abstract
Type 2 diabetes mellitus (T2DM) is a prevalent disease worldwide and during its conventional treatment, vascular complications remain unavoidable. Roux-en-Y gastric bypass (GBP) is able to induce the remission of T2DM. However, studies of duodenal-jejunal bypass (DJB), a modified procedure of GBP, are being carried out to investigate its ability to induce the remission of T2DM and protect the aorta from atherosclerosis. The present study aimed to investigate the effect of DJB on the rate of T2DM remission and the prevention of atherosclerosis in the aorta in rats with streptozotocin-induced diabetes without obesity, and to explore the mechanism of DJB in protecting the aorta from atherosclerosis. A T2DM rat model was established with a high-fat diet and low-dose streptozotocin. Surgery was performed to analyze its effects on glucose homeostasis, lipid metabolism, inflammation and pathological changes. Furthermore, changes in c-jun NH2-terminal kinase 1 (JNK1) and inhibitor of κB kinase (IKKβ) genes in the aorta following DJB surgery were examined. Levels of blood glucose, lipids, insulin and tumor necrosis factor (TNF)-α were significantly elevated in the T2DM diabetic model compared with the non-diabetic control. A gradual recovery was observed in the DJB group following surgery. Foam cells and atherosclerotic plaques appeared in the ascending aortic tissue in the sham-surgery and T2DM groups, whereas only slight lesions were observed in the DJB group. The expression levels of JNK1 and IKKβ genes in the aorta were significantly increased in the sham-operated and T2DM groups compared with those in the DJB and normal control groups. The present study demonstrated that DJB caused remission of T2DM without weight loss in non-obese rats. Thus, DJB may delay or prevent the occurrence and development of atherosclerosis in the aorta and this may occur through the JNK1 and nuclear factor κB (NF-κB) signaling pathways. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
28. Dilepton Rapidity Distribution in Drell-Yan Production to Third Order in QCD.
- Author
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Xuan Chen, Gehrmann, Thomas, Glover, Nigel, Huss, Alexander, Tong-Zhi Yang, and Hua Xing Zhu
- Subjects
- *
QUANTUM chromodynamics , *ORDER picking systems - Abstract
We compute for the first time the lepton-pair rapidity distribution in the photon-mediated Drell-Yan process to next-to-next-to-next-to-leading order in QCD. The calculation is based on the qT-subtraction method, suitably extended to this order for quark-antiquark initiated Born processes. Our results display sizeable QCD corrections at next-to-next-to-next-to-leading order over the full rapidity region and provide a fully independent confirmation of the recent results for the total Drell-Yan cross section at this order. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
29. PRACTICAL STABILITY OF IMPULSIVE FUNCTIONAL DIFFERENTIAL SYSTEMS VIA ANALYSIS TECHNIQUES.
- Author
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SHUN-XUAN CHEN and ZHI-QIANG ZHU
- Subjects
- *
INFINITY (Mathematics) , *EQUALITY , *TIME series analysis , *BERNOULLI effect (Fluid dynamics) , *TIME management - Abstract
In this paper we consider the practical stability for a class of functional differential system with impulses. By making use of the analysis techniques, specially, the Bernoulli inequality, we obtain some criteria to guarantee the practical stability of our system, including the finite-time stability and infinite-time stability. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
30. Influence of Nanoparticles and Graphite Foam on the Supercooling of Acetamide.
- Author
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Jia Yu, Xuan Chen, Xiaoliang Ma, Qingfei Song, Yukun Zhao, and Jiahao Cao
- Subjects
- *
GRAPHITE , *SUPERCOOLING , *NANOPARTICLES , *ACETAMIDE , *PHASE change materials , *HEAT storage - Abstract
Acetamide is a promising phase change materials (PCMs) for thermal storage,but the large supercooling during the freezing process has limited its application. In this study, we prepared acetamide-SiO2 composites by adding nano-SiO2 into acetamide. This modified PCM was then impregnated into the porous graphite foam forming acetamide-SiO2-graphite foam form-stable composites. These composites were subjected to melting-solidification cycles 50 times; the time-temperature curves were tracked and recorded during these cycles. The time-temperature curves showed that, for the acetamide containing 2 wt. % SiO2, the supercooling phenomenon was eliminated and the material's performance was stable for 50 cycles. The solidification temperature of the acetamide-SiO2-graphite foam samples was 65°C and the melting temperature was lowered to 65°C. The samples exhibited almost no supercooling and the presence of SiO2 had no significant effect on the melting-solidification temperature. The microscopic supercooling of the acetamide-SiO2 composite was measured using differential scanning calorimetry (DSC). The results indicated that when the content of SiO2 was 1 wt. to 2 wt. %, the supercooling could be reduced to less than 10°C and heat was sufficiently released during solidification. Finally, a set of algorithms was derived using MATLAB software for simulating the crystallization of samples based on the classical nucleation theory. The results of the simulation agreed with the experiment results. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
31. Zeros, Poles, and Fixed Points of Meromorphic Solutions of Difference Painlevé Equations.
- Author
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Shuang-Ting Lan and Zong-Xuan Chen
- Subjects
- *
PAINLEVE equations -- Numerical solutions , *MEROMORPHIC functions , *FIXED point theory , *TRANSCENDENTAL functions , *STOCHASTIC convergence , *NUMERICAL solutions to differential equations , *NUMERICAL analysis - Abstract
In this paper, we mainly study the properties of transcendental meromorphic solutions f(z) of difference Painlevé equations w(z + 1)w(z - 1)(w(z) - 1) = η(z)w²(z) - λ(z)w(z) and w(z + 1)w(z - 1)(w(z) - 1) = η(z)w(z) and obtain precise estimations of the exponents of convergence of zeros, poles of Δf(z) and Δf(z)/f(z), and of fixed points of f(z + c) for any c ∈ ℂ. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
32. On Properties of Meromorphic Solutions of Certain Difference Painlevé III Equations.
- Author
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Shuang-Ting Lan and Zong-Xuan Chen
- Subjects
- *
MEROMORPHIC functions , *MATHEMATICAL equivalence , *PAINLEVE equations , *TRANSCENDENTAL functions - Abstract
We mainly study the exponents of convergence of zeros and poles of difference and divided difference of transcendental meromorphic solutions for certain difference Painlevé III equations. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
33. A threshold method for immunological correlates of protection.
- Author
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Xuan Chen, Bailleux2, Fabrice, Desai, Kamal, Qin, Li, and Dunning, Andrew J.
- Subjects
- *
HEPATITIS A vaccines , *RUBELLA vaccines , *MEASLES vaccines , *VACCINATION , *JAPANESE encephalitis viruses , *IMMUNIZATION , *IMMUNOASSAY , *VACCINES , *GOODNESS-of-fit tests - Abstract
Background: Immunological correlates of protection are biological markers such as disease-specific antibodies which correlate with protection against disease and which are measurable with immunological assays. It is common in vaccine research and in setting immunization policy to rely on threshold values for the correlate where the accepted threshold differentiates between individuals who are considered to be protected against disease and those who are susceptible. Examples where thresholds are used include development of a new generation 13-valent pneumococcal conjugate vaccine which was required in clinical trials to meet accepted thresholds for the older 7-valent vaccine, and public health decision making on vaccination policy based on long-term maintenance of protective thresholds for Hepatitis A, rubella, measles, Japanese encephalitis and others. Despite widespread use of such thresholds in vaccine policy and research, few statistical approaches have been formally developed which specifically incorporate a threshold parameter in order to estimate the value of the protective threshold from data. Methods: We propose a 3-parameter statistical model called the a:b model which incorporates parameters for a threshold and constant but different infection probabilities below and above the threshold estimated using profile likelihood or least squares methods. Evaluation of the estimated threshold can be performed by a significance test for the existence of a threshold using a modified likelihood ratio test which follows a chi-squared distribution with 3 degrees of freedom, and confidence intervals for the threshold can be obtained by bootstrapping. The model also permits assessment of relative risk of infection in patients achieving the threshold or not. Goodness-of-fit of the a:b model may be assessed using the Hosmer-Lemeshow approach. The model is applied to 15 datasets from published clinical trials on pertussis, respiratory syncytial virus and varicella. Results: Highly significant thresholds with p-values less than 0.01 were found for 13 of the 15 datasets. Considerable variability was seen in the widths of confidence intervals. Relative risks indicated around 70% or better protection in 11 datasets and relevance of the estimated threshold to imply strong protection. Goodness-of-fit was generally acceptable. Conclusions: The a:b model offers a formal statistical method of estimation of thresholds differentiating susceptible from protected individuals which has previously depended on putative statements based on visual inspection of data. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
34. On a Conjecture Concerning Some Nonlinear Difference Equations.
- Author
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CHANG-WEN PENG and ZONG-XUAN CHEN
- Subjects
- *
DIFFERENCE equations , *DIFFERENCE sets , *MATHEMATICAL analysis , *NUMERICAL analysis - Abstract
In this paper, we mainly study non-existence of infinite order entire solutions of the nonlinear difference equation of the form f (z)n +q(z) f(z+1) = c sin bz, where n(≥ 2) is an integer, q(z) is a non-constant polynomial, which concerns a conjecture raised by Yang and Laine. [ABSTRACT FROM AUTHOR]
- Published
- 2013
35. On Growth of Meromorphic Solutions for Linear Difference Equations.
- Author
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Zong-Xuan Chen and Kwang Ho Shon
- Subjects
- *
MEROMORPHIC functions , *DIFFERENCE equations , *POLYNOMIALS , *RATIONAL numbers , *PROOF theory - Abstract
We mainly study growth of linear difference equations ... and ..., where, ..., are polynomials such that ... and give the most weak condition to guarantee that orders of all transcendental meromorphic solutions of the above equations are greater than or equal to 1. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
36. Fixed Points of Meromorphic Solutions for Some Difference Equations.
- Author
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Zong-Xuan Chen and Kwang Ho Shon
- Subjects
- *
FIXED point theory , *MEROMORPHIC functions , *DIFFERENCE equations , *EXPONENTS , *STOCHASTIC convergence , *LOGISTIC functions (Mathematics) - Abstract
We investigate fixed points of meromorphic solutions y(z) for the Pielou logistic equation and obtain some estimates of exponents of convergence of fixed points of y(z) and its shifts y(z+n), differences y(z) = y(z+1)/y(z), and divided differences y(z)/y(z). [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
37. Quantum Dots-Based Immunofluorescent Microfluidic Chip for the Analysis of Glycan Expression at Single-Cells.
- Author
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Jun-Tao Cao, Zi-Xuan Chen, Xiao-Yao Hao, Peng-Hui Zhang, and Jun-Jie Zhu
- Subjects
- *
CELL analysis , *GLYCAN analysis , *QUANTUM dots , *IMMUNOFLUORESCENCE , *CYTOLOGICAL research , *FLOW cytometry - Abstract
Rich high-quality single-cell information from rare cell sample is very important for the quantitative systems biology description of cellular function. However, this type of data is often prohibited by the conventional analytical technology such as flow cytometry. In this paper, we described a microfluidic platform coupled with a quantum dots-based (QDs) immunofluorescence (IF) approach to measure the expression of glycans on the cell surface of single cells or cell population. Compared with conventional IF staining, the QDs-based IF probe exhibited higher brightness and stability against photobleaching. With the merits of the novel IF staining protocol and microfluidic platform, high-throughput IF staining was performed to measure the glycan expressions and the changes at single K562 cells after drug treatment. The protocol proposed here showed a high sensitivity on the glycan expression profile owing to the amplification of the signal in indirect IF staining. The size of cell sample was only 4 × 10³ cells, which made the rare cell sample analysis accessible. This method may find widespread application for assessing cell-surface glycoprotein expression as well as analysis of the heterogeneity in cell populations in a high-throughput manner. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
38. Topologically reconfigurable magnetic polaritons.
- Author
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Min Li, Guangwei Hu, Xuan Chen, Cheng-Wei Qiu, Hongsheng Chen, and Zuojia Wang
- Subjects
- *
POLARITONS , *PHONONS , *GROUP velocity dispersion , *GROUP velocity , *PHASE change materials - Abstract
The article presents a study which demonstrated that the three-dimensional origami deformation allows to reconfigure hyperbolic or elliptic topology of polariton dispersion and modulate group velocity. Topics discussed include numerical simulations, microwave sample fabrication, and experimental measurements.
- Published
- 2022
- Full Text
- View/download PDF
39. Mettl3-mediated m6A modification of Fgf16 restricts cardiomyocyte proliferation during heart regeneration.
- Author
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Fu-Qing Jiang, Kun Liu, Jia-Xuan Chen, Yan Cao, Wu-Yun Chen, Wan-Ling Zhao, Guo-Hua Song, Chi-Qian Liang, Yi-Min Zhou, Huan-Lei Huang, Rui-Jin Huang, Hui Zhao, Kyu-Sang Park, Zhenyu Ju, Dongqing Cai, and Xu-Feng Qi
- Subjects
- *
HEART , *CARDIAC regeneration , *GENE expression , *RNA sequencing , *HEART injuries , *RNA analysis , *CONJOINT analysis - Abstract
Cardiovascular disease is the leading cause of death worldwide due to the inability of adult heart to regenerate after injury. N6-methyladenosine (m6A) methylation catalyzed by the enzyme methyltransferase-like 3 (Mettl3) plays an important role in various physiological and pathological bioprocesses. However, the role of m6A in heart regeneration remains largely unclear. To study m6A function in heart regeneration, we modulated Mettl3 expression in vitro and in vivo. Knockdown of Mettl3 significantly increased the proliferation of cardiomyocytes and accelerated heart regeneration following heart injury in neonatal and adult mice. However, Mettl3 overexpression decreased cardiomyocyte proliferation and suppressed heart regeneration in postnatal mice. Conjoint analysis of methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-seq identified Fgf16 as a downstream target of Mettl3-mediated m6A modification during postnatal heart regeneration. RIP-qPCR and luciferase reporter assays revealed that Mettl3 negatively regulates Fgf16 mRNA expression in an m6A-Ythdf2- dependent manner. The silencing of Fgf16 suppressed the proliferation of cardiomyocytes. However, the overexpression of ?Fgf16, in which the m6A consensus sequence was mutated, significantly increased cardiomyocyte proliferation and accelerated heart regeneration in postnatal mice compared with wild-type Fgf16. Our data demonstrate that Mettl3 post-transcriptionally reduces Fgf16 mRNA levels through an m6A-Ythdf2- dependen pathway, thereby controlling cardiomyocyte proliferation and heart regeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
40. Influence of Various Polymorphic Variants of Cytochrome P450 Oxidoreductase (POR) on Drug Metabolic Activity of CYP3A4 and CYP2B6.
- Author
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Xuan Chen, Li Qiang Pan, Naranmandura, Hua, Su Zeng, and Shu Qing Chen
- Subjects
- *
CYTOCHROME oxidase , *OXIDOREDUCTASES , *CYTOCHROMES , *PROTEINS , *ORGANIC compounds - Abstract
Cytochrome P450 oxidoreductase (POR) is known as the sole electron donor in the metabolism of drugs by cytochrome P450 (CYP) enzymes in human. However, little is known about the effect of polymorphic variants of POR on drug metabolic activities of CYP3A4 and CYP2B6. In order to better understand the mechanism of the activity of CYPs affected by polymorphic variants of POR, six full-length mutants of POR (e.g., Y181D, A287P, K49N, A115V, S244C and G413S) were designed and then co-expressed with CYP3A4 and CYP2B6 in the baculovirus-Sf9 insect cells to determine their kinetic parameters. Surprisingly, both mutants, Y181D and A287P in POR completely inhibited the CYP3A4 activity with testosterone, while the catalytic activity of CYP2B6 with bupropion was reduced to approximately ∼70% of wild-type activity by Y181D and A287P mutations. In addition, the mutant K49N of POR increased the CLint (Vmax/Km) of CYP3A4 up to more than 31% of wild-type, while it reduced the catalytic efficiency of CYP2B6 to 74% of wild-type. Moreover, CLint values of CYP3A4-POR (A115V, G413S) were increased up to 36% and 65% of wild-type respectively. However, there were no appreciable effects observed by the remaining two mutants of POR (i.e., A115V and G413S) on activities of CYP2B6. In conclusion, the extent to which the catalytic activities of CYP were altered did not only depend on the specific POR mutations but also on the isoforms of different CYP redox partners. Thereby, we proposed that the POR-mutant patients should be carefully monitored for the activity of CYP3A4 and CYP2B6 on the prescribed medication. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
41. First Record of Pyramica epinotalis (Hymenoptera: Formicidae) for the United States.
- Author
-
Xuan Chen, MacGown, Joe A., Adams, Benjamin J., Parys, Katherine A., Strecker, Rachel M., and Hooper-Bui, Linda
- Subjects
- *
HYMENOPTERA , *PLANT species , *ANTS , *PITFALL traps - Abstract
Pyramica epinotalis is an arboreal dacetine ant previously known only from Brazil, Costa Rica, Ecuador, and southern Mexico. Here we report the first records of P. epinotalis for the United States. Collections were made in three parishes across southern Louisiana in cypress-tupelo swamps using floating pitfall traps placed in floating vegetation and arboreal pitfall traps placed on trunks and limbs of three wetland tree species. One additional specimen of this species was collected in Highlands County, Florida. Based on collections of specimens in Louisiana, including multiple dealate females at different localities, P. epinotalis appears to be well established in this state. We discuss the design and implementation of modified arboreal pitfall traps that were instrumental in this discovery. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
42. Dynamic tensile behavior of two-dimensional carbon fiber reinforced silicon carbide matrix composites
- Author
-
Xuan, Chen and Yulong, Li
- Subjects
- *
FIBER-reinforced ceramics , *SILICON carbide , *DYNAMICS , *DELAMINATION of composite materials , *FRACTURE mechanics , *STRENGTH of materials - Abstract
Abstract: An investigation has been undertaken to determine the dynamic and quasi-static tensile behavior of two-dimensional carbon fiber reinforced silicon carbide matrix (2D-C/SiC) composites by means of the split Hopkinson tension bar and an electronic universal test machine respectively. The results indicate that the tensile strength of 2D C/SiC composites is increased at high strain rate. Furthermore, coated specimens show not only a 15% improvement in tensile strength but heightened strain rate sensitivity compared with uncoated ones. It is also shown that the tensile failure strain is strain rate insensitive and remains around 0.4%. Optical macrograph of failed specimens under dynamic loading revealed jagged fracture surfaces characterized by delamination and crack deviation, together with obvious fiber pull-out/splitting, in contrast with the smooth fracture surfaces under quasi-static loading. Scanning electron microscopy micrograph of fracture surface under dynamic loading clearly displayed integrated bundle pull-out which implies suppressed in-bundle debonding and enhanced in-bundle interfacial strengthening, in contrast with extensive in-bundle debonding under quasi-static loading. Thus we conclude that, with 2D C/SiC composites, the strain rate sensitivity of in-bundle interface is mainly responsible for the strain rate sensitivity of the tensile strength. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
43. Synthesis, characterization of star-shaped copolymers of l-lactide and epoxidized soybean oil.
- Author
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Jun Zou, Xuan Chen, You Shu, Haijun Zhou, and Farong Huang
- Subjects
- *
SOY oil , *COPOLYMERS , *POLYMERIZATION , *STABILITY (Mechanics) , *MONOMERS , *MOLECULAR weights , *DUCTILITY , *THERMAL properties - Abstract
Biodegradable star-shaped PLLA-ESO copolymers were synthesized by the bulk copolymerization of l-lactide ( l-LA) and epoxidized soybean oil (ESO) with stannous octanoate as the catalyst. Effects of molar ratios of monomer to catalyst, and various amounts of ESO on copolymerization were studied. The resulting copolymers were characterized by FTIR, H NMR, GPC, etc., which confirmed the successful synthesis of star-shaped copolymers of l-LA and ESO. The thermal and mechanical properties of samples were also investigated by means of DSC, TGA and tensile testing. The results showed that the PLLA-ESO copolymers possed lower glass transition temperature, melting point, crystallinity, and maximum decomposition temperature than those of neat polylactide. Tensile testing demonstrated that PLLA-ESO copolymer had better ductility than linear PLLA. It was also found that the amount of catalyst almost had no influence on the weight average molecular weight of PLLA-ESO copolymers, but which could be controlled by variation of molar ratios of l-LA to ESO. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
44. On Value Distribution of Difference Polynomials of Meromorphic Functions.
- Author
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Zong-Xuan Chen
- Subjects
- *
POLYNOMIALS , *MEROMORPHIC functions , *DISTRIBUTION (Probability theory) , *MATHEMATICAL constants , *STOCHASTIC convergence , *PROOF theory , *MATHEMATICAL functions - Abstract
We study the value distribution of the difference counterpart (Δ)f(z) - a f(z)n of f'(z) - a f(z)n and obtain an almost direct difference analogue of results of Hayman. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
45. Viscosity Calculations for Ionic LiquidâCosolvent Mixtures Based on Eyringâs Absolute Rate Theory and Activity Coefficient Models.
- Author
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Yang-guang Wang, Dong-xuan Chen, and Xiao-kun OuYang
- Subjects
- *
VISCOSITY , *IONIC liquids , *RATE distortion theory , *TRANSPORT theory , *MIXTURES , *PARAMETER estimation , *ACTIVITY coefficients , *CHEMICAL kinetics - Abstract
The modeling of transport properties of nonaqueous mixtures containing ionic liquids (ILs), such as viscosities, is still in its infancy. The aim of this work is to evaluate the capability of viscosity models that are based on Eyringâs absolute rate theory and activity coefficient models to nonaqueous mixtures containing ILs. The Eyring-NRTL (nonrandom two-liquid) and Eyring-UNIQUAC (universal quasichemical activity coefficient) equations were extended to modeling ILs with cosolvent mixtures. The results were compared and discussed. For systems with large nonideality the Eyring-NRTL equation needs three adjustable parameters to give satisfactory results, while the two-parameter Eyring-UNIQUAC model could give completely satisfactory results for these systems. Less adjustable parameters will be beneficial when limited experimental data are available. So, the Eyring-UNIQUAC equation was further simplified to have only one adjustable parameter by suitable assumptions. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
46. GROWTH OF MEROMORPHIC SOLUTIONS OF SOME DIFFERENCE EQUATIONS.
- Author
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Xiu-Min Zheng, Zong-Xuan Chen, and Jin Tu
- Subjects
- *
COMPUTATIONAL mathematics , *DIFFERENCE equations , *FINITE model theory , *ALGEBRA , *MATHEMATICAL analysis - Abstract
We investigate higher order difference equations and obtain some results on the growth of transcendental meromorphic solutions, which are complementary to the previous results. Examples are also given to show the sharpness of these results. We also investigate the growth of transcendental entire solutions of a homogeneous algebraic difference equation by using the difference analogue of Wiman-Valiron Theory. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
47. Entire Functions Sharing Fixed Points With Their Linear Differential Polynomials.
- Author
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Zhi-Qiang Mao and Zong-Xuan Chen
- Subjects
- *
DIFFERENTIAL dimension polynomials , *INTEGRAL functions , *STOCHASTIC convergence , *MATHEMATICAL constants , *MATHEMATICAL analysis , *FIXED point theory , *TRANSCENDENTAL functions , *POLYNOMIALS - Published
- 2010
48. The Zeros Distribution of Hyper Solutions of Higher Order Differential Equations in Angular Domain.
- Author
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Zhi-Bo Huang and Zong-Xuan Chen
- Subjects
- *
BOREL sets , *EQUATIONS , *LINEAR differential equations , *DISTRIBUTION (Probability theory) , *STOCHASTIC convergence - Abstract
In this paper, we investigate the location of zeros and Borel direction for the solutions of equations f(n) + An-2(z)f(n-2) + ⋯ + A1(z)f' + A0(z)f = 0(n≥2) (*) in an angular domain and obtain a sufficient and necessary condition between Borel direction and the hyper order exponent of convergence of zero sequence of E = f1 f2 ⋯ fn, where f1, f2,ȮG;, fn are n linearly independent solutions of the equation (*). This paper extends previous results. [ABSTRACT FROM AUTHOR]
- Published
- 2010
49. New subgenus of genus Hylaeus (Hymenoptera: Colletidae) with two new records from China.
- Author
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Xuan CHEN, Huanli XU, and DATHE, Holger H.
- Subjects
- *
HYLAEUS , *COLLETIDAE , *ANIMAL classification , *INSECTS , *ENTOMOLOGY research - Abstract
A new subgenus of the genus Hylaeus Fabricius, 1793 is described and illustrated. The subgenus Laxoprosopis subgen. nov. is erected for one new Chinese species, H. (Laxoprosopis) sichuanensis sp. nov. In addition, H. nipponicus Bridwell, 1919 and H. monticola Bridwell, 1919 are recorded from China for the first time. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
50. An Experimental Technique on the Dynamic Strength of Adhesively Bonded Single Lap Joints.
- Author
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Xuan Chen and Yulong Li
- Subjects
- *
ARTIFICIAL joints , *IMPACT loads , *IMPACT testing , *THERMAL stresses , *ADHESIVE joints , *ADHESIVES industry - Abstract
This paper reported an experimental technique on the shear strength of adhesively bonded single lap joints subjected to impact loads by means of a split Hopkinson tensile bar. The experiments were conducted at two velocities (V = 20 m/s, 7 m/s) and testing temperatures ranging from -40°C to 80°C. The results indicated that the shear strength of the specimen decreased with the increase of temperature and increased with the increase of velocity. The strength degradation from room temperature to high temperature was more severe than that from low temperature to room temperature. The effects of the pins, thermal stress and peel stress were also examined and found to have limited effects on the determination of the shear strength of the joints. It was concluded that the shear strength of the adhesively bonded single lap joints under impact loads can be determined by this experimental technique. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
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