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Search Results: 1 - 10 of 104397 matches for " ZHANG Yumei "
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The Critical Properties of a Modulated Quantum Sine-Gordon Model
Zhiguo Wang,Yumei Zhang
Physics , 2001,
Abstract: A new procedure of trial variational wave functional is proposed for investigating the mass renormailzation and the local structure of the ground state of a one-dimensional quantum sine-Gordon model with linear spatial modulation, whose ground state differs from that without modulation. The phase diagram obtained in parameters $(\alpha \Lambda ^{-2},\beta ^{2})$ plane shows that the vertical part of the boundary between soliton lattice phase and incommensurate (IC) phase with vanishing gap sticks at $\beta ^{2}$ $=4\pi $, the IC phase can only appear for $\beta ^{2}$ $\geq 4\pi $ and the IC phase regime is enlarged with increasing spatial modulation in the case of definite parameter $\alpha \Lambda ^{-2}$. The transition is of the continuous type on the vertical part of the boundary, while it is of the first order on the boundary for $\beta ^{2}>4\pi $.
The phase diagram of the one-dimensional quantum sine-Gordon system ($β^{2}=4π)$ with a linear spatial modulation
Zhiguo Wang,Yumei Zhang
Physics , 2001,
Abstract: The one-dimensional quantum sine-Gordon system with a linear spatial modulation is investigated in a special case, $\beta ^{2}$ =4$\pi $. The model is tranformed into a massive Thirring model and then is exactly diagonalized, the energy spetrum of the model is obtained. Our result clearly demonstrates that cancelling the cosine term without any considering is unadvisable.
The Area under the Curve (AUC) of Oral Glucose Tolerance Test (OGTT) Could Be a Measure Method of Hyperglycemia in All Pregnant Women  [PDF]
Congyue Zhang, Yumei Wei, Weijie Sun, Huixia Yang
Open Journal of Obstetrics and Gynecology (OJOG) , 2019, DOI: 10.4236/ojog.2019.92019
Abstract: Objective: We adopted the area under the curve (AUC) of oral glucose tolerance test (OGTT) as a measure method of the severity of maternal hyperglycemia and investigated its relationship with adverse perinatal outcomes among women with and without gestational diabetes mellitus (GDM). Research design and methods: This is a retrospective cohort study. Our study group collected the medical records of 15,296 women who received perinatal care in 15 hospitals in Beijing and who delivered from July 1, 2013, to December 31, 2013. And several original articles on this cohort have been published. In this study, we analyze the relationship between AUC and adverse perinatal outcomes, so that in multiple pregnant cases, patients with pre-pregnancy diabetes, hypertension, and abnormal kidney function and those who did not receive a 75-g OGTT were excluded. A Chi-squared test and logistic regression analysis were used to determine the associations. Results: In total, 13,561 women were included. As the AUC of OGTT increased, the prevalence of macrosomia (odds ratio [OR] 1.059, 95% confidence interval [95% CI] 1.029 - 1.090, p < 0.001) and hypertensive diseases (OR 1.106, 95% CI 1.064 - 1.149, p < 0.001) also increased. For patients with same levels of AUC values, no significant differences in the risk of macrosomia, preterm birth and neonatal complications were observed between the GDM and non-GDM groups. Women with an AUC higher than 14.20 (mmol *
Spin-Peierls transition in an anisotropic two-dimensional XY model
Qingshan Yuan,Yumei Zhang,Hong Chen
Physics , 1999, DOI: 10.1103/PhysRevB.64.012414
Abstract: The two-dimensional Jordan-Wigner transformation is used to investigate the zero temperature spin-Peierls transition for an anisotropic two-dimensional XY model in adiabatic limit. The phase diagram between the dimerized (D) state and uniform (U) state is shown in the parameter space of dimensionless interchain coupling $h$ $(=J_{\perp}/J)$ and spin-lattice coupling $\eta$. It is found that the spin-lattice coupling $\eta$ must exceed some critical value $\eta_c$ in order to reach the D phase for any finite $h$. The dependence of $\eta_c$ on $h$ is given by $-1/\ln h$ for $h\to 0$ and the transition between U and D phase is of first-order for at least $h>10^{-3}$.
Correlations between the ages ofAlnus host species and the genetic diversity of associated endosymbioticFrankia strains from nodules
Yumei Dai,Chenggang Zhang,Zhi Xiong,Zhongze Zhang
Science China Life Sciences , 2005, DOI: 10.1007/BF02889804
Abstract: Nodule samples were collected from four alder species:Alnus nepalensis, A. sibirica, A. tinctoria andA. mandshurica growing in different environments on Gaoligong Mountains, Yunnan Province of Southwest China and on Changbai Mountains, Jilin Province of Northeast China. PCR-RFLP analysis of the IGS betweennifD andnifK genes was directly applied to unculturedFrankia strains in the nodules. A total of 21 restriction patterns were obtained. TheFrankia population in the nodules ofA. nepalensis had the highest genetic diversity among all fourFrankia populations; by contrast, the population in the nodules ofA. mandshurica had the lowest degree of divergence; the ones in the nodules ofA. sibirica andA. tinctoria were intermediate. A dendrogram, which was constructed based on the genetic distance between the restriction patterns, indicated thatFrankia strains fromA. sibirica andA. tinctoria had a close genetic relationship.Frankia strains fromA. nepalensis might be the ancestor ofFrankia strains infecting otherAlnus species. From these results and the inference of the ages ofAlnus host species, it is deduced that there was a co-evolution betweenAlnus and its microsymbiontFrankia in China.
Down-regulation of SOCS3 Expression by Methylation Correlates with Lymph Node Metastases of NSCLCs
Siyang ZHANG,Qingfu ZHANG,Yumei GU,Enhua WANG
Chinese Journal of Lung Cancer , 2008,
Abstract: Background and objective It has been proven that suppressor of cytokine signaling 3 (SOCS3) contributes to inhibition of cell overgrowth, induction of apoptosis and stabilization. In the present study, we addressed the SOCS3 expression in non-small cell lung cancer (NSCLC) and explored the relationship between SOCS3 expression and lymph node metastases as well as clinicopathological characteristics in lung cancer patients. Methods Western blotting analysis was used to examine the expression of SOCS3 in 30 NSCLCs and non-tumor tissues. The methylated status of SOCS3 gene was determined by methylation-specific PCR (MSP) assay in the same 30 samples. Immunohistochemical staining was applied to determine SOCS3 expression in 90 NSCLC sections and the correlation of SOCS3 expression with lymph node metastases and clinicopathological characteristics was also analyzed. Results SOCS3 expression was much lower in 30 NSCLCs than tnat in non-tumorous counterparts of the same case (optical density were 26.3±12.3 and 78.4±14.5 respectively, P=0.000) by western blotting analysis. MSP showed that the methylated rate of SOCS3 gene was (20/30) 66.7% in NSCLCs, and (4/30) 13.3% in non-tumors, and SOCS3 expression was negatively correlated with methylation (r=-0.454, P=0.012). Furthermore, SOCS3 expression was observed in non-tumorous epithelial cells by immunohistochemiscal analysis, and the positive rate of SOCS3 expression in 90 NSCLC samples was (41/90) 45.6%. SOCS3 expression rate was lower in NSCLCs with lymph node metastases (35.4%) compared with non-metastatic NSCLCs (57.1%, P=0.039), and in NSCLCs of stage Ⅲ (36.4%) than in stage Ⅰ+Ⅱ (60.0%, P=0.028). SOCS3 expression was not correlated with histological type or differentiation (P>0.05). Conclusion The results of this study suggest that Down-regulation of SOCS3 expression in NSCLC associated with methylation might be correlated with lymph node metastases as well as clinicopathological stage of NSCLCs.
Relationship of Post-Stroke Aphasic Types with Sex, Age and Stroke Types  [PDF]
Jingfan Yao, Zaizhu Han, Yanli Song, Lei Li, Yun Zhou, Weikang Chen, Chunxue Wang, Yongjun Wang, Yumei Zhang
World Journal of Neuroscience (WJNS) , 2015, DOI: 10.4236/wjns.2015.51004
Abstract: Aim:To explore what is the relationship of the types of post-stroke aphasia with sex, age andstroke types.Methods:Retrospective analysis was administrated on data of 421 patients with acutestroke. Western battery aphasia was used to measure aphasiac type and aphasia quotient (AQ)score. The patients were divided into three age groups: young, middle-aged and elderly. The stroketypes were classified into cerebral infraction (CI) and intracerebral hemorrhage (ICH). Results: All subjects were right-handed, which males and females accounted for 69.60% and 30.40%, respectively. There were 116 cases of Broca’s aphasia (85 males), 35 cases of Wernicke’s aphasia (20 males),15 cases of conductive aphasia (10 males), 63 cases of transcortical motor aphasia (50 males), 11 cases of transcortical sensory aphasia (8 males), 27 cases of transcortical combined aphasia (13 males), 73 cases of anomic aphasia (47 males) and 81 cases of global aphasia (60 males). Male patients (69.60%) have a significantly higher morbidity of aphasia than that of females (30.40%) after stroke (χ2
Relationship of Post-Stroke Aphasic Types with Sex, Age and Stroke Types  [PDF]
Jingfan Yao, Zaizhu Han, Yanli Song, Lei Li, Yun Zhou, Weikang Chen, Yongmei Deng, Yongjun Wang, Yumei Zhang
World Journal of Neuroscience (WJNS) , 2015, DOI: 10.4236/wjns.2015.51004
Abstract: Aim: To explore what is the relationship of the types of post-stroke aphasia with sex, age and stroke types. Methods: Retrospective analysis was administrated on data of 421 patients with acute stroke. Western battery aphasia was used to measure aphasiac type and aphasia quotient (AQ) score. The patients were divided into three age groups: young, middle-aged and elderly. The stroke types were classified into cerebral infraction (CI) and intracerebral hemorrhage (ICH). Results: All subjects were right-handed, which males and females accounted for 69.60% and 30.40%, respectively. There were 116 cases of Broca’s aphasia (85 males), 35 cases of Wernicke’s aphasia (20 males), 15 cases of conductive aphasia (10 males), 63 cases of transcortical motor aphasia (50 males), 11 cases of transcortical sensory aphasia (8 males), 27 cases of transcortical combined aphasia (13 males), 73 cases of anomic aphasia (47 males) and 81 cases of global aphasia (60 males). Male patients (69.60%) have a significantly higher morbidity of aphasia than that of females (30.40%) after stroke (χ2 = 11.57
White Matter Changes in Alzheimer’s Disease Revealed by Diffusion Tensor Imaging with TBSS  [PDF]
Hongyan Chen, Kai Wang, Jingfan Yao, Jianping Dai, Jun Ma, Shaowu Li, Lin Ai, Qian Chen, Xuzhu Chen, Yumei Zhang
World Journal of Neuroscience (WJNS) , 2015, DOI: 10.4236/wjns.2015.51007
Abstract: Alzheimer’s disease (AD) is a progressive, neurodegenerative disorder characterized by impairments in multiple cognitive domains and it is hard to diagnose in early stage because it’s not easy to recognize and develop slowly. In this study, we try to evaluate the difference of white matter between AD and health volunteers using diffusion tensor imaging (DTI) and try to provide some evidence for diagnose AD in early stage. Twelve elderly Chinese patients with AD and twelve healthy volunteers were recruited and underwent DTI. The raw diffusion data were dealt with the toolkit of FSL image post-processing. Fractional anisotrogy (FA) data were then carried out by using tract-based spatial statistics (TBSS). The result showed that the FA of cingulum, hippocampus, corticospinal tract, and inferior fronto-occipital fasciculus significantly reduced in AD patients than that of volunteers. This indicated that the integrity of white matter tracts in these regions with AD was disturbed. On the other hand, the FA of other encephalic regions had no discrepancy compared with that of healthy volunteers. FA values were found reduced significantly in AD patients, especially in the posterior of the brain. These findings may provide image methods to diagnose patients with early stage of AD.
Research on the Influence of Urbanization on Income Gap between Urban and Rural Areas—Based on Income Source  [PDF]
Xiaomei Pu, Yumei Zhu
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.66013
Abstract: According to China’s panel data between 2002 and 2016, the present thesis first analyzed the overall effects and time effects of urbanization on wage disparity, net operating income disparity, net property income gap, and net transferred income disparity between urban and rural residents, and then analyzed the overall effects and time effects of each income disparity on the total income gap between urban and rural residents. In general, the impact of urbanization on urban-rural income disparity was studied from the perspective of income sources. The results show that urbanization bridges the income gap between urban and rural areas, with an inverted U-shaped structure which increases first and then narrows, from the income sources perspective. So, the targeted and operational policy recommendations are proposed.
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