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Search Results: 1 - 10 of 127005 matches for " Jingna Li "
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A Two-Dimensional Landau-Lifshitz Model in Studying Thin Film Micromagnetics
Jingna Li
Abstract and Applied Analysis , 2009, DOI: 10.1155/2009/603591
Abstract: The paper is concerned with a two-dimensional Landau-Lifshitzequation which was first raised by A. DeSimone and F. Otto, and so fourth, when studying thin film micromagnetics. We get the existence of a local weak solution by approximating it with a higher-order equation. Penalty approximation and semigroup theory are employed to deal with the higher-order equation.
Wide-Range Tunable Dynamic Property of Carbon Nanotube-Based Fibers
Jingna Zhao,Xiaohua Zhang,Zhijuan Pan,Qingwen Li
Physics , 2015, DOI: 10.1002/admi.201500093
Abstract: Carbon nanotube (CNT) fiber is formed by assembling millions of individual tubes. The assembly feature provides the fiber with rich interface structures and thus various ways of energy dissipation, as reflected by the non-zero loss tangent (>0.028--0.045) at low vibration frequencies. A fiber containing entangled CNTs possesses higher loss tangents than a fiber spun from aligned CNTs. Liquid densification and polymer infiltration, the two common ways to increase the interfacial friction and thus the fiber's tensile strength and modulus, are found to efficiently reduce the damping coefficient. This is because the sliding tendency between CNT bundles can also be well suppressed by the high packing density and the formation of covalent polymer cross-links within the fiber. The CNT/bismaleimide composite fiber exhibited the smallest loss tangent, nearly as the same as that of carbon fibers. At a higher level of the assembly structure, namely a multi-ply CNT yarn, the inter-fiber friction and sliding tendency obviously influence the yarn's damping performance, and the loss tangent can be tuned within a wide range, as similar to carbon fibers, nylon yarns, or cotton yarns. The wide-range tunable dynamic properties allow new applications ranging from high quality factor materials to dissipative systems.
Assembly-Dependent Interfacial Property of Carbon Nanotube Fibers with Epoxy and Its Enhancement via Generalized Surface Sizing
Chaoshuai Lei,Jingna Zhao,Jingyun Zou,Chunyang Jiang,Min Li,Xiaohua Zhang,Zuoguang Zhang,Qingwen Li
Physics , 2015,
Abstract: In building up composite structures using carbon nanotube (CNT) fibers, the fiber-to-matrix interfacial shear strength (IFSS) is one of the most important issues. Originating from the assembly characteristics of CNT fiber, the IFSS strongly depends on the fiber's twisting level and densification level. Furthermore, there are rich ways to modify the fiber surface and thus enhance the IFSS, including the physical and chemical modification on fiber surface, the infiltration of matrix resin into CNT fiber, and the introduction of silane coupling agent. A new feature differing from carbon fibers is that all these treatments either change the fiber's surface structure or form a several-hundreds-nm-thick interphase inside rather than around the fiber. These "generalized" treatments obviously extend the common concept of surface sizing and can be used for various forms of CNT assembly structures.
Design and Implementation of a New Chinese Word Segmentation Dictionary for the Personalized Mobile Search  [PDF]
Zhongmin Wang, Jingna Qi, Yan He
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.51B019
Abstract: Chinese word segmentation is the basis of natural language processing. The dictionary mechanism significantly influences the efficiency of word segmentation and the understanding of the user’s intention which is implied in the user’s query. As the traditional dictionary mechanisms can't meet the present situation of personalized mobile search, this paper presents a new dictionary mechanism which contains the word classification information. This paper, furthermore, puts forward an approach for improving the traditional word bank structure, and proposes an improved FMM segmentation algorithm. The results show that the new dictionary mechanism has made a significant increase on the query efficiency and met the user’s individual requirements better.
Severe Maternal Hyperglycemia Exacerbates the Development of Insulin Resistance and Fatty Liver in the Offspring on High Fat Diet
Yong Song,Jibin Li,Yong Zhao,Qijuan Zhang,Zhiguo Liu,Jingna Li,Xiaoyi Chen,Zhu Yang,Chao Yu,Xiaoqiu Xiao
Experimental Diabetes Research , 2012, DOI: 10.1155/2012/254976
Abstract: Background. Adverse maternal environments may predispose the offspring to metabolic syndrome in adulthoods, but the underlying mechanism has not been fully understood. Methods. Maternal hyperglycemia was induced by streptozotocin (STZ) injection while control (CON) rats received citrate buffer. Litters were adjusted to eight pups per dam and then weaned to standard diet. Since 13 weeks old, a subset of offspring from STZ and CON dams were switched to high fat diet (HFD) for another 13 weeks. Glucose and insulin tolerance tests (GTT and ITT) and insulin secretion assay were performed; serum levels of lipids and leptin were measured. Hepatic fat accumulation and islet area were evaluated through haematoxylin and eosin staining. Results. STZ offspring exhibited lower survival rate, lower birth weights, and growth inhibition which persisted throughout the study. STZ offspring on HFD showed more severe impairment in GTT and ITT, and more profound hepatic steatosis and more severe hyperlipidemia compared with CON-HFD rats. Conclusions. Offspring from diabetic dams would be prone to exhibit low birth weight and postnatal growth inhibition, but could maintain normal glucose tolerance and insulin sensitivity. HFD accelerates development of insulin resistance in the offspring of diabetic dams mainly via a compensatory response of islets.
Negative Emotion Regulation in Patients with Posttraumatic Stress Disorder
Kunlin Xiong, Ye Zhang, Mingguo Qiu, Jingna Zhang, Linqiong Sang, Li Wang, Bing Xie, Jian Wang, Min Li
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0081957
Abstract: Objective To explore the neural mechanisms of negative emotion regulation in patients with post-traumatic stress disorder (PTSD). Methods Twenty PTSD patients and 20 healthy subjects were recruited. Event-related functional magnetic resonance imaging (fMRI) was used to investigate the modification of emotional responses to negative stimuli. Participants were required to regulate their emotional reactions according to the auditory regulation instructions via headphones, to maintain, enhance or diminish responses to negative stimuli during fMRI scans. Results The PTSD group showed poorer modification performance than the control group when diminishing responses to negative stimuli. On fMRI, the PTSD group showed decreased activation in the inferior frontal cortex, inferior parietal lobule, insula and putamen, and increased activation in posterior cingulate cortex and amygdala during up-regulation of negative emotion. Similar decreased activation regions were found during down-regulation of negative emotion, but no increased activation was found. Conclusion Trauma exposure might impair the ability to down-regulate negative emotion. The present findings will improve our understanding of the neural mechanisms of emotion regulation underlying PTSD.
Severe Maternal Hyperglycemia Exacerbates the Development of Insulin Resistance and Fatty Liver in the Offspring on High Fat Diet
Yong Song,Jibin Li,Yong Zhao,Qijuan Zhang,Zhiguo Liu,Jingna Li,Xiaoyi Chen,Zhu Yang,Chao Yu,Xiaoqiu Xiao
Journal of Diabetes Research , 2012, DOI: 10.1155/2012/254976
Abstract: Background. Adverse maternal environments may predispose the offspring to metabolic syndrome in adulthoods, but the underlying mechanism has not been fully understood. Methods. Maternal hyperglycemia was induced by streptozotocin (STZ) injection while control (CON) rats received citrate buffer. Litters were adjusted to eight pups per dam and then weaned to standard diet. Since 13 weeks old, a subset of offspring from STZ and CON dams were switched to high fat diet (HFD) for another 13 weeks. Glucose and insulin tolerance tests (GTT and ITT) and insulin secretion assay were performed; serum levels of lipids and leptin were measured. Hepatic fat accumulation and islet area were evaluated through haematoxylin and eosin staining. Results. STZ offspring exhibited lower survival rate, lower birth weights, and growth inhibition which persisted throughout the study. STZ offspring on HFD showed more severe impairment in GTT and ITT, and more profound hepatic steatosis and more severe hyperlipidemia compared with CON-HFD rats. Conclusions. Offspring from diabetic dams would be prone to exhibit low birth weight and postnatal growth inhibition, but could maintain normal glucose tolerance and insulin sensitivity. HFD accelerates development of insulin resistance in the offspring of diabetic dams mainly via a compensatory response of islets. 1. Introduction Metabolic syndrome (MetS) is a clustering of metabolic disorders including hyperglycemia, hypertension, dyslipidemia, overweight, and central obesity, with insulin resistance as the central feature of this syndrome [1]. A global increase in the prevalence of MetS has been found in the last decades due to the worldwide epidemic of obesity [2, 3]. The risk of the MetS depends on genetic susceptibility but is modulated by pre- and postnatal environmental factors. A growing body of evidence suggests that adverse environmental conditions during crucial periods of development may predispose individuals to develop different components of the MetS in adulthood [4]. Of particular note is maternal diabetes, including type 1 and type 2 diabetes and gestational diabetes mellitus (GDM). An overall increasing prevalence of diabetes indicates an emergence of diabetes among childbearing women. During pregnancy, especially during critical window periods for organogenesis and fetal development, unsatisfactory glycemic control is known to increase the incidence of severe obstetrical complications, including preeclampsia, macrosomia, and Caesarean section. Additionally, intrauterine exposure to a hyperglycemic environment predisposes
Bio-Inspired Aggregation Control of Carbon Nanotubes for Ultra-Strong Composites
Yue Han,Xiaohua Zhang,Xueping Yu,Jingna Zhao,Shan Li,Feng Liu,Peng Gao,Yongyi Zhang,Tong Zhao,Qingwen Li
Physics , 2015, DOI: 10.1038/srep11533
Abstract: High performance nanocomposites require well dispersion and high alignment of the nanometer-sized components, at a high mass or volume fraction as well. However, the road towards such composite structure is severely hindered due to the easy aggregation of these nanometer-sized components. Here we demonstrate a big step to approach the ideal composite structure for carbon nanotube (CNT) where all the CNTs were highly packed, aligned, and unaggregated, with the impregnated polymers acting as interfacial adhesions and mortars to build up the composite structure. The strategy was based on a bio-inspired aggregation control to limit the CNT aggregation to be sub 20--50 nm, a dimension determined by the CNT growth. After being stretched with full structural relaxation in a multi-step way, the CNT/polymer (bismaleimide) composite yielded super-high tensile strengths up to 6.27--6.94 GPa, more than 100% higher than those of carbon fiber/epoxy composites, and toughnesses up to 117--192 MPa. We anticipate that the present study can be generalized for developing multifunctional and smart nanocomposites where all the surfaces of nanometer-sized components can take part in shear transfer of mechanical, thermal, and electrical signals.
Multiallelic epistatic model for an out-bred cross and mapping algorithm of interactive quantitative trait loci
Chunfa Tong, Bo Zhang, Zhong Wang, Meng Xu, Xiaoming Pang, Jingna Si, Minren Huang, Rongling Wu
BMC Plant Biology , 2011, DOI: 10.1186/1471-2229-11-148
Abstract: Here we have formulated a general framework to model and define the epistasis between multiallelic QTLs. Based on this framework, we have derived a statistical algorithm for the estimation and test of multiallelic epistasis between different QTLs in a full-sib family of outcrossing species. We used this algorithm to genomewide scan for the distribution of mul-tiallelic epistasis for a rooting ability trait in an outbred cross derived from two heterozygous poplar trees. The results from simulation studies indicate that the positions and effects of multiallelic QTLs can well be estimated with a modest sample and heritability.The model and algorithm developed provide a useful tool for better characterizing the genetic control of complex traits in a heterozygous family derived from outcrossing species, such as forest trees, and thus fill a gap that occurs in genetic mapping of this group of important but underrepresented species.Approaches for quantitative trait locus (QTL) mapping were developed originally for experimental crosses, such as the backcross, double haploid, RILs or F2, derived from inbred lines [1-3]. Because of the homozygosity of inbred lines, the Mendelian (co)segregation of all markers each with two alternative alleles in such crosses can be observed directly. In practice, there is also a group of species of great economical and environmental importance - out-crossing species, such as forest trees, in which traditional QTL mapping approaches cannot be appropriately used. For these species, it is difficult or impossible to generate inbred lines due to long generation intervals and high heterozygosity [4], although experimental hybrids have been commercially used in practical breeding programs.For a given outbred line, some markers may be heterozygous, whereas others may be homozygous over the genome. All markers may, or may not, have the same allele system between any two outbred lines used for a cross. Also, for a pair of heterozygous loci, their allel
Quantitative assessment of microbicide-induced injury in the ovine vaginal epithelium using confocal microendoscopy
Gracie Vargas, Igor Patrikeev, Jingna Wei, Brent Bell, Kathleen Vincent, Nigel Bourne, Massoud Motamedi
BMC Infectious Diseases , 2012, DOI: 10.1186/1471-2334-12-48
Abstract: A quantitative approach using confocal fluorescence microendoscopy (CFM) for assessment of microbicide-induced injury to the vaginal epithelium was developed. Sheep were treated intravaginally with one of five agents in solution (PBS; 0.02% benzalkonium chloride (BZK); 0.2% BZK) or gel formulation (hydroxyethyl cellulose (HEC); Gynol II nonoxynol-9 gel (N-9)). After 24 hours the vaginal tract was removed, labeled with propidium iodide (PI), imaged, then fixed for histology. An automated image scoring algorithm was developed for quantitative assessment of injury and applied to the data set. Image-based findings were validated with histological visual gradings that describe degree of injury and measurement of epithelial thickness.Distinct differences in PI staining were detected following BZK and N-9 treatment. Images from controls had uniformly distributed nuclei with defined borders, while those after BZK or N-9 showed heavily stained and disrupted nuclei, which increased in proportion to injury detected on histology. The confocal scoring system revealed statistically significant scores for each agent versus PBS controls with the exception of HEC and were consistent with histology scores of injury.Confocal microendoscopy provides a sensitive, objective, and quantitative approach for non-invasive assessment of vaginal epithelial integrity and could serve as a tool for real-time safety evaluation of emerging intravaginal topical agents.Effective preclinical microbicide safety testing is of great importance to insure that only the most promising candidates are advanced to clinical trials. This is particularly important in light of the fact that several clinical trials of emerging microbicides have been terminated due to safety concerns [1-3]. Several early microbicide candidates were shown to increase susceptibility to infection in vivo [4,5] and were associated with surface epithelial disruption and inflammation [4-6]. Additionally, undetected changes in the epithelia
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