18 results on '"Xiao Xia Li"'
Search Results
2. Method to evaluate heat leakage of vertical cryogenic vessels at different liquid levels
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Zheng-qing Li, Sheng-sheng Yang, Xiao-jun Wang, and Xiao-xia Li
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Mechanics of Materials ,Mechanical Engineering - Published
- 2021
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3. Optical Response with Tunneling Coupling in a Hybrid Optomechanical System
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Xiao-Xia Li, Jing-Yan Li, Xu-Xin Cheng, and Guang-an Li
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Physics and Astronomy (miscellaneous) ,General Mathematics - Published
- 2022
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4. One-year efficacy of intravitreal conbercept injection for macular oedema secondary to central retinal vein occlusion in Chinese patients
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Hui-Yang Zeng, Xiao-Xia Li, Qian Liu, Yunxiao Sun, and Zi-Jun Zhang
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China ,medicine.medical_specialty ,Visual acuity ,genetic structures ,Recombinant Fusion Proteins ,Visual Acuity ,Angiogenesis Inhibitors ,Macular oedema ,Macular Edema ,Conbercept ,chemistry.chemical_compound ,Primary outcome ,Central retinal vein occlusion ,Pro re nata ,Ranibizumab ,Ophthalmology ,Retinal Vein Occlusion ,Correspondence ,Humans ,Medicine ,Retrospective Studies ,business.industry ,Retinal ,Retrospective cohort study ,medicine.disease ,eye diseases ,Treatment Outcome ,chemistry ,Intravitreal Injections ,medicine.symptom ,business ,Tomography, Optical Coherence - Abstract
To evaluate intravitreal conbercept injection for treatment of macular oedema secondary to central retinal vein occlusion (CRVO) in Chinese patients during 1-year follow-up in the real-world setting. Twenty-seven eyes of 27 patients with macular oedema associated with CRVO were retrospectively reviewed. The eyes received monthly intravitreal conbercept injection (0.5 mg in 50 µl) for 3 months. From then on, the patients were followed up every month and received injection pro re nata (PRN) up to 12 months. The primary outcome measurements included changes of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to month 3 and month 12. Other outcome measurements included proportion of patients gaining ≥15 letters in BCVA at month 3 and 12, the mean number of injections and safety concerns. The mean BCVA gain from baseline was 12.7 ± 7.6 letters at month 3 and 14.8 ± 9.6 letters at month 12. The mean CRT reduction from baseline was 374.5 ± 280.7 μm at month 3 and 428.2 ± 241.3 μm at month 12. The proportion of patients who gained ≥15 letters in BCVA was 45.1% at month 3 and 52.9% at month 12. The mean number of injections was 7.6 ± 1.5. No severe local and systemic complications occurred following injection. Intravitreal conbercept injection by three monthly loading doses followed by PRN treatment regimen was safe and efficacious for patients with macular oedema secondary to CRVO through 1-year follow-up.
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- 2020
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5. Predicting California-bearing capacity value of stabilized pond ash with lime and lime sludge applying hybrid optimization algorithms
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Xiao-xia, Li, primary
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- 2022
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6. Fabrication of Ag–ZnO@ carboxymethyl cellulose/K-carrageenan/graphene oxide/konjac glucomannan hydrogel for effective wound dressing in nursing care for diabetic foot ulcers
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Ming Lei, Jie Zhong, Qin-Qin Yu, Yong-Hua Li, Hu Yu, Jia-Yan Dong, and Xiao-Xia Li
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Materials Science (miscellaneous) ,Nanochemistry ,macromolecular substances ,02 engineering and technology ,010402 general chemistry ,complex mixtures ,01 natural sciences ,Silver nanoparticle ,Nursing care ,chemistry.chemical_compound ,medicine ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Fibroblast ,Chemistry ,technology, industry, and agriculture ,Cell Biology ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Carrageenan ,Carboxymethyl cellulose ,medicine.anatomical_structure ,Swelling ,medicine.symptom ,0210 nano-technology ,Wound healing ,Biotechnology ,Nuclear chemistry ,medicine.drug - Abstract
In the present investigation, a new Ag–ZnO loaded carboxymethyl cellulose/K-carrageenan/graphene oxide/konjac glucomannan (Ag–ZnO@CGK) hydrogel was effectively prepared by means of a straight forward two step technique for clinical applications as wound-recuperating materials. In the first step, silver nanoparticles were synthesized with green deoxidizer mango peel extracts. The Ag–ZnO@CGK hydrogel indicated incredible swelling assimilation and impressive mechanical properties. Also, Ag–ZnO@CGK hydrogel exhibited great bactericidal movement against test microorganisms. In vitro viability testing demonstrated that fibroblast cells could endure well within the sight of Ag@CGK hydrogel, showing that Ag–ZnO@CGK hydrogel has great viability. In vivo animal models demonstrated that the Ag–ZnO@CGK hydrogel adequately quickened wound recuperating and histological examinations demonstrated that they have advanced fibroblast development and quickened epithelialization. The test results demonstrated that Ag–ZnO@CGK hydrogel has incredible potential in advanced wound healing.
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- 2019
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7. Two-scale mathematical model for tsunami wave
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Qura Tul Ain, Xiao-Xia Li, and Naveed Anjum
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Surface (mathematics) ,Scale (ratio) ,Differential equation ,Mathematical analysis ,Boundary (topology) ,Fluid mechanics ,010103 numerical & computational mathematics ,010502 geochemistry & geophysics ,Space (mathematics) ,01 natural sciences ,Fractal ,Modeling and Simulation ,General Earth and Planetary Sciences ,0101 mathematics ,0105 earth and related environmental sciences ,Physical law ,Mathematics - Abstract
Scale or dimension is critical for all physical laws, and different scales might result in distinct and sometimes contradicting laws for the same phenomenon. In this study, the idea of the two-scale fractal is utilized to model the time-fractional tsunami wave traveling on an unsmooth surface. Mass and momentum conservation equations are established in a fractal space. To covert the considered fractional model into a differential equation, the fractional complex transform is used, then He’s variational iteration method is adopted to solve the resultant equation. The fractal model helps in studying the dynamic behavior of tsunami wave and their prevention through boundary control. The present study sheds new light on two-scale fluid mechanics.
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- 2021
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8. Noninvasive high-frequency oscillatory ventilation as respiratory support in preterm infants: a meta-analysis of randomized controlled trials
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Xianmei Huang, Jing Li, Zhi-Qun Zhang, and Xiao-Xia Li
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0301 basic medicine ,medicine.medical_specialty ,Noninvasive high-frequency oscillatory ventilation ,medicine.medical_treatment ,Continuous positive airway pressure ,MEDLINE ,High-Frequency Ventilation ,Lower risk ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,law ,medicine ,Humans ,Intubation ,Randomized Controlled Trials as Topic ,lcsh:RC705-779 ,Respiratory Distress Syndrome, Newborn ,Noninvasive Ventilation ,business.industry ,Research ,Infant, Newborn ,Infant ,Preterm infants ,lcsh:Diseases of the respiratory system ,Bronchopulmonary dysplasia ,Respiratory support ,Confidence interval ,030104 developmental biology ,030228 respiratory system ,Meta-analysis ,Emergency medicine ,business ,Infant, Premature - Abstract
Background Noninvasive high-frequency oscillatory ventilation (nHFOV), a relatively new modality, is gaining popularity despite scarce evidence. This meta-analysis was designed to evaluate the efficacy and safety of nHFOV as respiratory support in premature infants. Methods We searched MEDLINE, EMBASE, CINAHL, and Cochrane CENTRAL from inception of the database to January 2019. All published randomized controlled trials (RCTs) evaluating the effect of nHFOV therapy with nasal continuous positive airway pressure (nCPAP) or biphasic nCPAP (BP-CPAP) in newborns for respiratory support were included. All meta-analyses were performed using Review Manager 5.3. Results A total of 8 RCTs involving 463 patients were included. The meta-analysis estimated a lower risk of intubation (relative risk = 0.50, 95% confidence interval of 0.36 to 0.70) and more effective clearance of carbon dioxide (weighted mean difference = − 4.61, 95% confidence interval of − 7.94 to − 1.28) in the nHFOV group than in the nCPAP/BP-CPAP group. Conclusions Our meta-analysis of RCTs suggests that nHFOV, as respiratory support in preterm infants, significantly remove carbon dioxide and reduce the risk of intubation compared with nCPAP/BP-CPAP. The appropriate parameter settings for different types of noninvasive high-frequency ventilators, the effect of nHFOV in extremely preterm infants, and the long-term safety of nHFOV need to be assessed in large trials.
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- 2019
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9. The influence of near work on myopic refractive change in urban students in Beijing: a three-year follow-up report
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Ningli Wang, Xiao Xia Li, Yuanbo Liang, Vishal Jhanji, Kenneth J. Ciuffreda, Balamurali Vasudevan, Hong Jia Zhou, Guang Yun Mao, and Zhong Lin
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Male ,China ,Refractive error ,medicine.medical_specialty ,Time Factors ,Adolescent ,Urban Population ,genetic structures ,Refraction, Ocular ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Surveys and Questionnaires ,Ophthalmology ,Activities of Daily Living ,Myopia ,medicine ,Humans ,Vision test ,Age of Onset ,Child ,Students ,Prospective cohort study ,Retrospective Studies ,Schools ,business.industry ,Incidence ,Vision Tests ,Hazard ratio ,medicine.disease ,Sensory Systems ,Confidence interval ,Quartile ,Cohort ,Disease Progression ,030221 ophthalmology & optometry ,Female ,sense organs ,business ,030217 neurology & neurosurgery ,Follow-Up Studies ,Cohort study ,Demography - Abstract
To investigate the influence of daily activities on myopic refractive change and myopic onset in Chinese urban students. The Beijing Myopia Progression Study was a 3-year cohort study. Cycloplegic refraction and a daily activity questionnaire were assessed at baseline and at follow-up examinations. Refractive change was defined as the difference in cycloplegic spherical equivalent (SE) between the final follow-up and baseline. 386 students were initially enrolled in the baseline study. At the final follow-up, 222 students (57.5 %) with completed refractive error and daily activity data were analyzed. These students spent 0.32 ± 2.33 h/day more on near work (p = 0.04), and 0.21 ± 1.31 h/day less on outdoor leisure (p = 0.02), than they did at baseline. In the multivariate analysis, the younger among the secondary students (β = 0.06, p
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- 2016
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10. PTEN expression is upregulated by a RNA-binding protein RBM38 via enhancing its mRNA stability in breast cancer
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Xi Sun, Qiang Ding, Ying Wang, Jia-Yi Qian, Jing Wu, Lei Zhu, Liang Shi, Xu-Jie Zhou, Ji-Fu Wei, and Xiao-Xia Li
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0301 basic medicine ,PTEN ,Cancer Research ,RNA Stability ,Breast Neoplasms ,RBM38 ,RNA-binding protein ,lcsh:RC254-282 ,03 medical and health sciences ,Breast cancer ,0302 clinical medicine ,Cell Line, Tumor ,Humans ,Tensin ,RNA, Messenger ,mRNA stability ,3' Untranslated Regions ,Gene ,PI3K/AKT/mTOR pathway ,Messenger RNA ,Binding Sites ,biology ,Three prime untranslated region ,Research ,PTEN Phosphohydrolase ,RNA-Binding Proteins ,RNA ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Prognosis ,Growth suppression ,Up-Regulation ,Gene Expression Regulation, Neoplastic ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,Cancer research ,biology.protein ,Female - Abstract
Background PTEN (phosphatase and tensin homolog gene on chromosome 10), a well-characterized tumor suppressor, is a key regulator of the phosphatidylinositol-3-kinase (PI3K)/AKT pathway involved in cell survival, metastasis and cell renewal. PTEN expression is closely related to the phenotype, prognosis and drug selection in breast cancer. It is mainly regulated by transcriptional and post-transcriptional modifications. RNA binding motif protein 38 (RBM38), an RNA-binding protein (RBP) and a target of P53 family, plays a crucial role in the regulation of cellular processing, especially in post-transcription regulation and gene transcription. In this study, we investigated a new post-transcription regulation mechanism of PTEN expression by RBM38 in breast cancer. Methods Immunohistochemistry, lentivirus transfections, Western blotting analysis, qRT-PCR and ELISA were used to conduct the relation between RBM38 and PTEN. RNA immunoprecipitation, RNA electrophoretic mobility shift and dual-luciferase reporter assays were employed to identify the direct binding sites of RBM38 with PTEN transcript. Colony formation assay was conducted to confirm the function of PTEN in RBM38-induced growth suppression. Results PTEN expression was positively associated with the expression of RBM38 in breast cancer tissues and breast cancer cells. Moreover, RBM38 stabilized PTEN transcript to enhance PTEN expression via binding to multiple AU/U- rich elements (AREs) in 3′-untranslated region (3′-UTR) of PTEN transcript. Additionally, specific inhibitors of PTEN activity and small interfering (siRNA) of PTEN expression inhibited RBM38-mediated suppression of proliferation, which implied that RBM38 acted as a tumor suppressor partly by enhancing PTEN expression. Conclusion The present study revealed a new PTEN regulating mechanism that PTEN was positively regulated by RBM38 via stabilizing its transcript stability, which in turn alleviated RBM38-mediated growth suppression. Electronic supplementary material The online version of this article (10.1186/s13046-017-0620-3) contains supplementary material, which is available to authorized users.
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- 2017
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11. The role of c-Myc-RBM38 loop in the growth suppression in breast cancer
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Tiansong Xia, Lei Zhu, Xi Sun, Qiang Ding, Liang Shi, Wenbin Zhou, Xu-Jie Zhou, Jing Wu, Ji-Fu Wei, and Xiao-Xia Li
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0301 basic medicine ,Cancer Research ,Breast Neoplasms ,RBM38 ,Biology ,lcsh:RC254-282 ,Proto-Oncogene Proteins c-myc ,03 medical and health sciences ,Breast cancer ,Cell Line, Tumor ,Humans ,mRNA stability ,Promoter Regions, Genetic ,3' Untranslated Regions ,Transcription factor ,Gene ,Cell Proliferation ,Neoplasm Staging ,Messenger RNA ,Gene knockdown ,RNA recognition motif ,Research ,RNA-Binding Proteins ,Promoter ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Growth suppression ,Gene Expression Regulation, Neoplastic ,Blot ,c-Myc ,030104 developmental biology ,Oncology ,MCF-7 Cells ,Cancer research ,Female ,Chromatin immunoprecipitation - Abstract
Background RNA-binding protein 38 (RBM38) is a member of the RNA recognition motif (RRM) family of RNA-binding proteins (RBPs). RBM38 often exerts its function by forming regulatory loops with relevant genes. c-Myc is an oncogenic transcription factor that is upregulated in one-third of breast cancers and involved in many cellular processes in this malignancy. In our previous study, RBM38 was identified as a tumor suppressor in breast cancer. In the present study, we investigated the mechanisms underlying the regulation of this tumor suppressor. Methods Lentivirus transfections, Western blotting analysis, qRT-PCR and immunohistochemistry were employed to study the expression of c-Myc and RBM38. Chromatin immunoprecipitation and dual-luciferase reporter assays were performed to investigate the direct relationship between c-Myc protein and the RBM38 gene. RNA immunoprecipitation combined with dual-luciferase reporter assays was conducted to confirm the direct relationship between the RBM38 protein and the c-Myc transcript. Results Knockdown of c-Myc increased RBM38 expression by binding directly to specific DNA sequences (5′-CACGTG-3′), known as the E-box motif, in the promoter region of RBM38 gene. Additionally, RBM38 destabilized the c-Myc transcript by directly targeting AU-rich elements (AREs) in the 3′-untranslated region (3′-UTR) of c-Myc mRNA to suppress c-Myc expression. Moreover, specific inhibitors of c-Myc transcriptional activity inhibited RBM38-induced suppression of growth, implying that RBM38 acts as a tumor suppressor via a mechanism that depends, at least partially, on the reduction of c-Myc expression in breast cancer. Conclusions RBM38 and c-Myc form a unique mutually antagonistic RBM38-c-Myc loop in breast cancer. Electronic supplementary material The online version of this article (doi:10.1186/s13046-017-0521-5) contains supplementary material, which is available to authorized users.
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- 2017
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12. Remission of rheumatoid arthritis and potential determinants: a national multi-center cross-sectional survey
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Sa-Li Zhang, Li-Jun Song, Fengxiao Zhang, Jing Yang, Min Feng, Xiaoyuan Wang, Bei Lai, Zhuoli Zhang, Bai-Lu Liu, Hongtao Jin, Liu Jt, Rong Yang, Yanhua Wang, Ci-Bo Huang, Cong Ye, Yan Wang, Xiao-Xia Li, Mei-Qiu Wei, Rong Shu, Li-Jun Wu, Ai-Xue Wang, Wen-Wen Sun, Haiying Chen, Ping Wei, Xiuru Wang, Ming Gao, Lan He, X. Li, Lu Gong, Liu Xm, Guanying Wang, Dan Ke, Ping Yu, Yan Zhang, Yuan An, Rong Mu, Zhanguo Li, Shaoxian Hu, Hui-Ming Yan, Jian-Li Xie, Hao Li, Bin Jia, Yin Su, Chun Li, Ping Zhu, Wang Jx, Zhen-Bin Li, Wang Lz, Yi Zhao, Xiaofeng Li, Yongfu Wang, Xin Lu, Shuling Han, Junfang Li, Lin Sun, Guangtao Li, Xiao-Min Liu, Jinying Lin, Li-na Chen, Liu Xy, Yong-Jing Cheng, Hui-Fang Guo, Cai-Hong Wang, Jie-Mei Tao, Yi Wang, Xiuyan Yang, Chun-Fang Zhang, Xiao-Xia Yu, Guochun Wang, and Liufu Cui
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Adult ,Male ,musculoskeletal diseases ,China ,medicine.medical_specialty ,Cross-sectional study ,Arthritis ,Severity of Illness Index ,Arthritis, Rheumatoid ,Rheumatology ,Risk Factors ,Internal medicine ,Humans ,Medicine ,Rheumatoid factor ,skin and connective tissue diseases ,Aged ,business.industry ,Remission Induction ,Hydroxychloroquine ,General Medicine ,Middle Aged ,medicine.disease ,Cross-Sectional Studies ,Treatment Outcome ,Antirheumatic Agents ,Rheumatoid arthritis ,Cohort ,Physical therapy ,Female ,business ,Rheumatism ,medicine.drug - Abstract
The aim of this study is to investigate the remission rate of rheumatoid arthritis (RA) in China and identify its potential determinants. A multi-center cross-sectional study was conducted from July 2009 to January 2012. Data were collected by face-to-face interviews of the rheumatology outpatients in 28 tertiary hospitals in China. The remission rates were calculated in 486 RA patients according to different definitions of remission: the Disease Activity Score in 28 joints (DAS28), the Simplified Disease Activity Index (SDAI), the Clinical Disease Activity Index (CDAI), and the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Boolean definition. Potential determinants of RA remission were assessed by univariate and multivariate analyses. The remission rates of RA from this multi-center cohort were 8.6 % (DAS28), 8.4 % (SDAI), 8.2 % (CDAI), and 6.8 % (Boolean), respectively. Favorable factors associated with remission were: low Health Assessment Questionnaire (HAQ) score, absence of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP), and treatment of methotrexate (MTX) and hydroxychloroquine (HCQ). Younger age was also predictive for the DAS28 and the Boolean remission. Multivariate analyses revealed a low HAQ score, the absence of anti-CCP, and the treatment with HCQ as independent determinants of remission. The clinical remission rate of RA patients was low in China. A low HAQ score, the absence of anti-CCP, and HCQ were significant independent determinants for RA remission.
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- 2014
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13. Genetic diversity analysis of yams (Dioscorea spp.) cultivated in China using ISSR and SRAP markers
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Chuan Yin Fan, Xiao Xia Li, Nitin Mantri, Wu Jiang, Zheng Ming Tao, Xiao Qing Bao, Zhi Gang Wu, and Xin Chun Lin
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Genetic diversity ,Sequence-related amplified polymorphism ,biology ,Dioscorea alata ,Group method ,Plant Science ,biology.organism_classification ,Analysis of molecular variance ,Gene flow ,Dioscorea persimilis ,Botany ,Genetics ,Dioscorea ,Agronomy and Crop Science ,Ecology, Evolution, Behavior and Systematics - Abstract
Yam (Dioscorea spp.) is widely cultivated in China and many landraces are maintained by local farmers. However, there is little information available about their diversity and species identity. In this study, inter simple sequence repeat (ISSR) and sequence related amplified polymorphism (SRAP) techniques were used to assess genetic diversity within 21 yam landraces from seven cultivated populations. We observed high level of polymorphism among these landraces, specifically, 95.3 % for ISSR and 93.5 % for SRAP. Analysis of molecular variance revealed a significantly greater variation among the four yam species (40.39 %) and their populations (35.78 %) than within the populations (23.83 %). The unweighted pair group method arithmetic averages clusters and principal component analysis for 21 landraces formed four well-separated groups containing landraces of each of the four species, namely, Dioscorea opposita Thunb., Dioscorea alata L., Dioscorea persimilis Prain et Burkill, and Dioscorea fordii Prain et Burkill. The ISSR and SRAP primers were highly discriminatory among the 21 landraces; all 21 landraces could be easily differentiated using these primers. The average mean of gene flow (Nm = 0.1081) estimated from high genetic differentiation (Gst = 0.8222) suggested that gene flow among the populations was relatively restricted. The lack of genetic diversity within individual yam species suggests that it is critical to develop long-term strategies for enhancing genetic diversity within various yam species.
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- 2014
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14. Effect of annealing on photoluminescence of blue-emitting ZnO nanoparticles by sol–gel method
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Guoping Du, Han Wang, Andy Y. M. Suen, Nan Chen, Xiao Xia Li, and Zhong Chen
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Materials science ,Photoluminescence ,Condensed Matter::Other ,Scanning electron microscope ,Annealing (metallurgy) ,Physics::Optics ,Nanoparticle ,General Chemistry ,Condensed Matter Physics ,Microstructure ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Condensed Matter::Materials Science ,Crystallography ,Crystallinity ,Chemical engineering ,Materials Chemistry ,Ceramics and Composites ,Powder diffraction ,Wurtzite crystal structure - Abstract
In this work, we investigated the influence of annealing on the crystallinity, microstructures, and photoluminescence (PL) properties of ZnO nanoparticles prepared by sol–gel method. The annealing was carried out both in air and vacuum. X-ray powder diffraction, scanning electron microscopy, and ultraviolet–visible spectroscopy were used to characterize the crystal structures, diameter, surface morphology, and PL properties of ZnO nanoparticles. It has been found that both the as-grown and annealed ZnO nanoparticles had a hexagonal wurtzite crystal structure, and their average diameter and crystallinity increased with the anneal time and temperature. Pure blue-emitting behavior was observed in all samples. The emission intensity of ZnO nanoparticles was found to be enhanced after annealing, but it was highly dependent on the annealing conditions. Optimal annealing conditions both in air and vacuum were obtained for achieving maximum emission intensity in the ZnO nanoparticles. The dependence of PL properties of the ZnO nanoparticles on the annealing conditions was discussed.
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- 2012
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15. When interspecific prezygotic barriers break down: hybridization between two Potamogeton species (P. wrightii and P. perfoliatus) and comparison of the artificial and natural hybrids
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You-Hao Guo, Xiao-Xia Li, Le-Yi Ni, and Xiao-lin Zhang
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biology ,media_common.quotation_subject ,Plant Science ,Interspecific competition ,biology.organism_classification ,Plant ecology ,Speciation ,Germination ,Backcrossing ,Botany ,Pollen tube ,Potamogeton ,Ecology, Evolution, Behavior and Systematics ,media_common ,Hybrid - Abstract
Interspecific hybridization played an important role in speciation and evolution of angiosperms. Although the widespread occurrence of natural hybrids in the genus Potamogeton has been studied intensively, few successful experimental hybridization studies have been reported in this genus. In the present study, critical experimental hybridization was conducted using Potamogeton x intortusifolius, a natural hybrid widely distributed in China, and its parents (P. perfoliatus and P. wrightii). The absence of prezygotic barriers between P. wrightii and P. perfoliatus was observed, which contributes to the frequent hybridization of these species in nature. The pollen tube growth rates of P. perfoliatus were much faster than those of P. wrightii in the style of that species. However, the conspecific pollen tubes were competitively advantageous in P. perfoliatus styles. The interspecific hybridization could be applied bidirectionally, and 28 F1 hybrid individuals were successfully obtained from P. wrightii x P. perfoliatus, despite the low germination possibility of the hybrid seeds. Both the artificial and natural hybrids exhibited intermediate morphological characters but presented much lower fertility. The sterility of P. x intortusifolius is mainly due to its low female fitness. However, the offspring from P. wrightii x P. x intortusifolius indicated the potential for backcrossing in nature. This is the most successful attempt at artificial hybridization in this genus so far. The possible route for restoration of fertility and the fitness of the hybrids are also discussed in this paper.
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- 2011
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16. Dependence of domain wall structures on repetition n in [Pt(0.5 nm)/Co(0.4 nm)] n /NiO(1.1 nm)/[Co(0.4 nm)/Pt(0.5 nm)] n multilayers
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Xiao-xia Li and Gang Han
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Materials science ,Condensed matter physics ,Magnetometer ,Mechanical Engineering ,Non-blocking I/O ,Metals and Alloys ,Analytical chemistry ,law.invention ,Coupling (electronics) ,Condensed Matter::Materials Science ,Domain wall (magnetism) ,Ferromagnetism ,Geochemistry and Petrology ,Mechanics of Materials ,law ,Materials Chemistry ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Perpendicular anisotropy ,Magnetic force microscope - Abstract
The magnetic force microscopy and a sample vibrating magnetometer have been used to investigate the domain structure in two antiferromagnetically coupled Co/Pt multilayers. In the antiferromagnetic coupled [Pt(0.5 nm)/Co(0.4 nm)] n /NiO(1.1 nm)/[Co(0.4 nm)/Pt(0.5 nm)] n multilayers with perpendicular anisotropy, the antiferromagnetic interlayer coupling strength increases linearly with the repetition number n in Co/Pt multilayers. In demagnetized states, relatively shifted domain walls in the two Co/Pt multilayers are observed, with net ferromagnetic stripes formed between them for the repetition number n less than 5, and the stripe width decreases with the increase of n. The occurrence of these features can be attributed to the competition between the interlayer coupling and magnetostatic energies.
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- 2010
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17. Photoluminescence properties of BaGdB9O16:Tb3+ codoped Zn2+ or Ce3+ under ultraviolet and vacuum ultraviolet excitation
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Xiao Xia Li and Yu Hua Wang
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Photoluminescence ,Materials science ,business.industry ,Mechanical Engineering ,Analytical chemistry ,Phosphor ,Condensed Matter Physics ,medicine.disease_cause ,Emission intensity ,Vacuum ultraviolet ,Mechanics of Materials ,medicine ,Optoelectronics ,General Materials Science ,Luminescence ,Absorption (electromagnetic radiation) ,business ,Excitation ,Ultraviolet - Abstract
Single phase of Ba1−xZnxGd0.75Tb0.25B9O16 and BaGd0.75−xCexTb0.25B9O16 (0 ≤ x ≤ 0.125) was prepared by the solid-state reaction. Under 254 nm excitation, Zn2+ impaired the emission of Tb3+; Ce3+ sensitized the luminescence of Tb3+ ascribing to the energy transfer of Ce3+ → Tb3+ and/or Ce3+ → Gd3+ → Tb3+ occurring, and the optimum emission was observed at x = 0.05 in BaGd0.75−xCexTb0.25B9O16. Under 147 nm excitation, Zn2+ sensitized the emission of Tb3+ and the optimum emission was obtained at x = 0.075 in Ba1−xZnxGd0.75Tb0.25B9O16, which could be due to the fact that the energy absorption relating to Zn2+ occurred and the absorbed energy was transferred to Tb3+ finally; Ce3+ depressed the luminescence of Tb3+, which could be attributed to the fact that Ce3+ has no absorption in vacuum ultraviolet region and the role of Gd3+ was weakened. Compared with BaGd0.75Tb0.25B9O16 and the commercial phosphor Zn2SiO4:Mn2+, the optimum phosphor Ba0.925Zn0.075Gd0.75Tb0.25B9O16 exhibited about 127% and 51% integrated emission intensity respectively and the shorter decay time of about 2.822 ms under 147 nm excitation.
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- 2007
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18. The kinetics of oxidation curing of polycarbosilane fibers
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Xiaodong Li, Hao Wang, Xiao-xia Li, Bin Zhu, and Dong-Pyo Kim
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Materials science ,Chemical engineering ,Kinetic equations ,General Chemical Engineering ,Polymer chemistry ,Kinetics ,General Chemistry ,Activation energy ,Curing (chemistry) ,Catalysis - Abstract
For the oxidation curing of polycarbosilane (PCS) fibers in air, a first-order reaction based on the weight gain w (in percentage) was approached with the kinetic equation dw/dt=k(wm-w). The maximum weight gain wm was observed to be 16% under normal oxidation conditions and the activation energy E to be 79.27 kJ/mol. The numeric integration based on the kinetics provides a precise prediction of the curing degree of PCS fibers under various heating programs and conditions.
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- 2004
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