30 results on '"Yongxin Yan"'
Search Results
2. Effects of Chromium Carbide Coatings on Microstructure and Thermal Conductivity of Mg/Diamond Composites Prepared by Squeeze Casting
- Author
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Jianwei Li, Ren Peng, Jinming Ru, Jianhua Wu, Kaixiang Zhou, Yongxin Yan, Xiaojing Xu, and Yuhua Zhou
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Mg/diamond composites ,thermophysical properties ,interface ,squeeze casting ,General Materials Science - Abstract
Magnesium matrix composites are considered a desired solution for lightweight applications. As an attractive thermal management material, diamond particle-reinforced Mg matrix (Mg/diamond) composites generally exhibit thermal conductivities lower than expected. To exploit the potential of heat conduction, a combination of Cr coating on diamond particles and squeeze casting was used to prepare Mg/diamond (Cr) composites. The thickness of the Cr coating under different coating processes (950 °C/30 min, 950 °C/60 min, 950 °C/90 min, 1000 °C/30 min, and 1050 °C/30 min) was measured by FIB-SEM to be 1.09–2.95 μm. The thermal conductivity (TC) of the Mg/diamond composites firstly increased and then decreased, while the coefficient of thermal expansion (CTE) of Mg/diamond (Cr) composite firstly decreased and then increased with the increase in Cr coating thickness. The composite exhibited the maximum TC of 202.42 W/(m·K) with a 1.20 μm Cr coating layer, while a minimum CTE of 5.82 × 10−6/K was recorded with a coating thickness of 2.50 μm. The results clearly manifest the effect of Cr layer thickness on the TC and CTE of Mg/diamond composites.
- Published
- 2022
3. Treatment of type 1 diabetes by regulatory T‐cell infusion via regulating the expression of inflammatory cytokines
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Dong Yin, Guofeng Wang, Yuan Hui, Ning Xu, and Yongxin Yan
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Male ,0301 basic medicine ,endocrine system ,medicine.medical_specialty ,endocrine system diseases ,Regulatory T cell ,Enzyme-Linked Immunosorbent Assay ,chemical and pharmacologic phenomena ,Real-Time Polymerase Chain Reaction ,T-Lymphocytes, Regulatory ,Biochemistry ,Glucagon ,Proinflammatory cytokine ,Interferon-gamma ,03 medical and health sciences ,0302 clinical medicine ,Transforming Growth Factor beta ,Internal medicine ,medicine ,Animals ,RNA, Messenger ,IL-2 receptor ,Interleukin-7 receptor ,Molecular Biology ,Cells, Cultured ,business.industry ,nutritional and metabolic diseases ,Interleukin ,hemic and immune systems ,Cell Biology ,Streptozotocin ,Interleukin-10 ,Rats ,Diabetes Mellitus, Type 1 ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,030220 oncology & carcinogenesis ,Cytokines ,Interleukin-2 ,Interleukin-4 ,business ,CD8 ,medicine.drug - Abstract
Objective To explore the role and molecular mechanism of regulatory T (Treg) cells in type 1 diabetes (T1D). Methods Patients with T1D and the healthy volunteers were selected and a number of CD3+ , CD4+ , CD25+ , and CD127- T cells were determined. The rats were divided into the control, T1D model, and Treg infusion (T1D rats were infused with Treg) group. The number of CD4+ , CD8- , and CD25+ T cells in the three groups were determined by flow cytometry. Weight, blood glucose, serum insulin, peptide C, glucagon, and glucagon like peptide 1 in the three groups were also determined. The messenger RNA (mRNA) levels and contents of interleukin (IL)-10, IL-4, transforming growth factor (TGF)-β, IL-2, IL-17, and IFN-γ in patients with T1D, healthy volunteers, streptozotocin (STZ)-induced T1D rat model, the control rat, and Treg infusion rats were determined by reverse transcription polymerase chain reaction and the enzyme-linked immunosorbent assay, respectively. Results Treg content in patients with T1D was significantly decreased compared with the control volunteers. Treg content in rats was markedly decreased after injection with STZ to induce T1D rat model, while Treg infusion weakened the decrease. The change scope of weight and blood glucose in the model and Treg group was bigger than the control group, and the change in the infusion group was lighter than the model group. T1D decreased the expressions of IL-10, IL-4, TGF-β, and IL-2, while Treg infusion weakened the decrease. The expressions of IL-17 and IFN-γ in the T1D group was increased, while Treg infusion weakened the increase. Conclusion Autologous Treg infusion can strengthen the immunologic and islet function to treat T1D which may be via regulating the expression of inflammatory factors.
- Published
- 2019
4. Upregulation of microRNA‐424 relieved diabetic nephropathy by targeting Rictor through mTOR Complex2/Protein Kinase B signaling
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Guofeng Wang, Dong Yin, Yuan Hui, Yongxin Yan, and Ning Xu
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Blood Glucose ,Male ,0301 basic medicine ,Physiology ,Clinical Biochemistry ,Down-Regulation ,Apoptosis ,Mechanistic Target of Rapamycin Complex 2 ,Kidney Function Tests ,mTORC2 ,Rats, Sprague-Dawley ,Diabetic nephropathy ,03 medical and health sciences ,0302 clinical medicine ,Downregulation and upregulation ,Western blot ,medicine ,Animals ,Humans ,Diabetic Nephropathies ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Base Sequence ,medicine.diagnostic_test ,Chemistry ,Cell Biology ,medicine.disease ,Up-Regulation ,Disease Models, Animal ,MicroRNAs ,Diabetes Mellitus, Type 1 ,Glucose ,Rapamycin-Insensitive Companion of mTOR Protein ,030104 developmental biology ,030220 oncology & carcinogenesis ,Protein kinase B signaling ,Mesangial Cells ,Cancer research ,Proto-Oncogene Proteins c-akt ,Signal Transduction - Abstract
Objective To investigate the role of miR-424 in diabetic nephropathy (DN) and its relationship with Rictor in mammalian target of rapamycin (mTOR) C2/Akt signaling. Methods The western blot analysis and real-time polymerase chain reaction were used to determine the differential expression of Rictor, mTOR, and miR-424 in DN rats. The upregulation of miR-424 was achieved by caudal vein injection of miR-424 mimics. The renal lesion was evaluated by hematoxylin-eosin staining (H&E) and periodic acid schiff staining. The dual-luciferase reporter assay was conducted to determine the binding target of miR-424. The effect of miR-424 upregulation on apoptosis was detected by the terminal deoxynucleotidyl transferase-mediated 2-Deoxyuridine-5-Triphosphate (dUTP) nick-end labeling assay and western blot analysis. Results A significantly lower expression of miR-424 and a significantly higher expression of Rictor and mTOR were found in renal tissues of DN rats. The upregulation of miR-424 improved renal lesion and DN symptoms of blood glucose level, urine protein level, body weight, creatinine level, blood urea nitrogen, and KW/BW ratio. The upregulation of miR-424 could significantly reduce apoptosis rates of tissue cells by decreasing the expression levels of caspase-3 and Bax as well as increasing the level of Bcl-2. Furthermore, Rictor was the direct target for miR-424, and upregulation of miR-424 inhibited Rictor through Akt signaling in renal tissue of DN rats and high-glucose-treated human glomerular mesangial cells. Conclusion miR-424 contributes to alleviating the symptoms in DN rat models by targeting Rictor through mTORC2/Akt signaling.
- Published
- 2019
5. Predictive values of obesity categories for cardiovascular disease risk factors in Chinese adult population
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Ning Xu, Guanjun Han, Yongxin Yan, Ning Ma, Chuanhui Yang, Dong Yin, Guofeng Wang, and Yuan Hui
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0301 basic medicine ,Waist ,Framingham Risk Score ,business.industry ,Cell Biology ,Odds ratio ,medicine.disease ,Lower risk ,Biochemistry ,Obesity ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Medicine ,Metabolic syndrome ,business ,Molecular Biology ,Body mass index ,Dyslipidemia ,Demography - Abstract
OBJECTIVE Whether obesity categories can be used to predict cardiovascular disease (CVD) in Chinese adults remains unclear. This aim of this study was to examine the predictive values of obesity categories for CVD risk factors in Chinese adults. METHODS This study comprised a sample size of 3480 men and 6364 women aged ≥25 years (age range 25-89 years), from the medical health check-up center of Lianyungang First People's Hospital. The following CVD risk factor outcomes were used: hypertension, diabetes, dyslipidemia, insulin resistance, and metabolic syndrome (Mets). Framingham risk scores were used to evaluate the CVD. Four categories of obesity were used, based on body mass index (BMI) and waist circumference: no risk, increased risk, high risk, and very high risk. Predictive abilities were determined by calculating the odds ratios (OR) of CVD risk. RESULTS A graded linear relationship between obesity categories and CVD risk was observed across the categories, except for dyslipidemia. The people in the very high-risk category had the highest OR of having more unfavorable CVD risk factors compared with those in the lower risk category. For example, the OR of diabetes increased with the increase in risk category (OR, 1.13, 1.36, and 1.83, respectively, for increased, high, and very high risk categories in men and OR, 1.52, 1.80, and 2.78, respectively, for increased, high, and very high risk category in women). CONCLUSIONS These findings suggest that obesity categories provide clinical insights into identifying multiple CVD risk factors in Chinese adults.
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- 2018
6. The mechanism of hsa-miR-424-5 combining PD-1 through mTORC signaling pathway to stimulate immune effect and participate in Type 1 diabetes
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Yongxin Yan, Tongyu Zhang, Zhichen Zheng, and Guofeng Wang
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0301 basic medicine ,Male ,Cell signaling ,type 1 diabetes ,hsa-miR-424-5p ,Programmed Cell Death 1 Receptor ,Biophysics ,mechanism ,mTORC1 ,CXCR3 ,Biochemistry ,Cell Line ,Diabetes Mellitus, Experimental ,03 medical and health sciences ,0302 clinical medicine ,Western blot ,microRNA ,medicine ,Animals ,immune effect ,Rats, Wistar ,Molecular Biology ,Research Articles ,Diabetes & Metabolic Disorders ,geography ,geography.geographical_feature_category ,biology ,medicine.diagnostic_test ,Chemistry ,TOR Serine-Threonine Kinases ,signal molecule ,Cell Biology ,Islet ,Gastrointestinal, Renal & Hepatic Systems ,Cell biology ,Rats ,body regions ,MicroRNAs ,030104 developmental biology ,Diabetes Mellitus, Type 1 ,030220 oncology & carcinogenesis ,embryonic structures ,biology.protein ,Signal transduction ,mTORC signaling pathway ,RHEB ,Signal Transduction - Abstract
In the present study, hsa-miR-424-5p mimic plasmid and hsa-mir-424-5p inhibitor plasmid were designed and injected into rats respectively, and miRNA control plasmid was also constructed. Models of Type 1 diabetes (T1D) were built. After successful modeling, the expression of hsa-miR-424-5p in lymphocytes was analyzed by RT-PCR. The expression of protein PD-1, T-bet, CXCR3, STING in Th1 lymphocytes and content of IGF-1 in islet tissue were analyzed by flow analysis. The protein levels of SHP2, Rheb, mTORC1, Rictor and Raptor in islet tissue were analyzed by Western blot. The results showed that hsa-miR-424-5p mimic group had the highest expression of hsa-miR-424-5p in lymphocytes. The expression of PD-1 was in hsa-miR-424-5p inhibitor > miRNA control > hsa-miR-424-5p mimic, while the expression of T-bet, CXCR3 and STING was in hsa-miR-424-5p mimic > miRNA control > hsa-miR-424-5p inhibitor. The expression of IGF-1 protein in hsa-miR-424-5p inhibitor group was the highest (32.08%) and hardly expressed in hsa-miR-424-5p mimic group (2.36%). The expression of SHP2, Rheb, mTORC1, Rictor and Raptor of insulin histoproteins were in hsa-miR-424-5p mimic group > miRNA control of > hsa-miR-424-5p inhibitor group, with statistical differences. It indicates that hsa-miR-424-5p binding PD-1 signaling molecules can stimulate the immune effect through the mTORC signaling pathway and participates in the pathogenesis of T1D.
- Published
- 2019
7. Intercalation of phosphotungstic acid into layered double hydroxides by reconstruction method and its application in intumescent flame retardant poly (lactic acid) composites
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Yongxin Yan, Wenjia Wang, Hongfei Li, Jianhua Li, Jun Sun, Xiaoyu Gu, and Sheng Zhang
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Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,Layered double hydroxides ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Limiting oxygen index ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Cone calorimeter ,Materials Chemistry ,engineering ,Phosphotungstic acid ,Char ,Composite material ,0210 nano-technology ,Intumescent ,Fire retardant - Abstract
Phosphotungstic acid is a typical kind of superior catalysts, and it is hardly to intercalate into the layered double hydroxides (LDH) by ion-exchange process because of its low negative charge. In this work, a phosphotungstic acid intercalated MgAl-LDH (PWA-LDH) was prepared by reconstruction method, and it was then introduced into poly (lactic acid) (PLA) resin in association with intumescent flame retardant (IFR) by melt blending to prepare a flame-retardant biodegradable PLA composite. The effects of PWA-LDH on the flame retardancy of PLA composites were characterized by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test. The results showed that the composite sample containing 18.0 wt% IFR and 2.0 wt% PWA-LDH achieved the maximal LOI value of 48.3%, passed the UL-94 V-0 rating, and significantly decreased the peak heat release rate from 306.3 kW/m2 of neat PLA to 40.1 kW/m2. Thermogravimetric analysis showed that both the thermal stability and the char formation were enhanced. The char morphology observation revealed that PWA-LDH was beneficial to form dense and compact char layers. It was demonstrated that there existed a synergistic effect between IFR and PWA-LDH in promoting the char formation and enhancing the fire resistance.
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- 2018
8. New method for the reconstruction of sedimentary systems including lithofacies, environments, and flow paths: A case study of the Xisha Trough Basin, South China Sea
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Yuanhao Li, Mei Chen, Wei Xian, Jingtan Chen, Gang Chen, Jian He, Suaibing Luo, Caijun Hong, Jianhui Han, Ceixia Hua, Lei Wang, Guoqiang Xu, Xiong Pang, Kai Liu, Hui Chen, Luo Wei, Xiaoxue Wang, Baojun Liu, Hu Lian, Shihu Wu, Wei Guo, Ganglian Song, Li Zhang, Yeyong Wang, Xiaogang Li, Ciming Yuan, Yongxin Yan, Changrong Wu, Jian Wang, Yinhui Zuo, Penghui Han, and Shaohua Xu
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Provenance ,Stratigraphy ,Marine geology ,Trough (geology) ,Borehole ,Geology ,Structural basin ,Oceanography ,Deep sea ,Sedimentary depositional environment ,Paleontology ,Geophysics ,Economic Geology ,Sedimentary rock - Abstract
Existing seismic facies analysis schemes, including traditional seismic facies analysis, seismic slice analysis, and automatic classification of seismic facies, can reconstruct the sedimentary systems of basins; however, they are not ideal for basins with few boreholes and many rock types. Herein, we propose a new method for reconstructing sedimentary systems using seismic data, considering the Xisha Trough Basin in the Northern South China Sea as the research object to demonstrate the principles, methods, and technologies of this novel scheme. Based on the six commonly used seismic parameters, three additional seismic parameters (smoothness, neatness, and special waveform) and one geological marker (provenance) were added to improve the recognition of lithofacies. The scanned seismic interpretation technique was used to describe the distribution of sandstone and other skeleton lithofacies; sedimentary environments were determined according to the coastline, shelf break line, and slope toe line; flow path systems were determined according to the paleotopography, incised valleys, and sandstone distribution; and the sedimentary systems of the trough basin were reconstructed through the superposition of skeleton lithofacies, depositional environments, and flow paths. Results show that the sedimentary system reconstructed using the new method contains three elements, namely, lithofacies, the environment, and flow path, which fully reflect the concept of the sedimentary system defined by Fisher and McGowen (1967) ; this overcomes the inherent defects of previous schemes, such as poor lithofacies recognition and the uncertainty of types and boundaries of sedimentary bodies. This method enabled identifying subdivided seismic lithofacies directly from seismic profiles and enhanced the ability to obtain sedimentary information from seismic data. The proposed reconstruction method can be used in areas without boreholes or with many rock types and is significant for marine geology research and oil and gas exploration conducted in the deep sea.
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- 2021
9. Iso-suillin-induced DNA damage leading to cell cycle arrest and apoptosis arised from p53 phosphorylation in A549 cells
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Li'an Wang, Zhi-qiang Jia, Junxia Zhao, Sheng-jie Yao, and Yongxin Yan
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Pharmacology ,A549 cell ,Cell cycle checkpoint ,Chemistry ,DNA damage ,Myeloid leukemia ,Cell Cycle Checkpoints ,In vitro ,Phenols ,A549 Cells ,In vivo ,Apoptosis ,Carcinoma, Non-Small-Cell Lung ,Cancer research ,Humans ,Phosphorylation ,Diterpenes ,Tumor Suppressor Protein p53 - Abstract
Extensive investigations have revealed that iso-suillin, a secondary metabolite isolated from Suillus flavus, could induce cell cycle arrest and apoptosis in human chronic myeloid leukemia K562 cells, human hepatocellular carcinoma SMMC-7721 cell line, and human small cell lung cancer H446 cell line in vitro. In the present study, human lung cancer A549 cells were used to reveal the mechanism of iso-suillin's effects on lung adenocarcinoma, which were detected both in vitro and in vivo. Results showed that iso-suillin potently inhibited A549 cell proliferation through an early G1 arrest. Iso-suillin also induced A549 cell apoptosis in vitro. Phosphorylation of p53 at serines 15 and 20 may be one of the pivotal factors for cell cycle arrest and apoptosis after treatment of iso-suillin in A549 cells. Moreover, in an A549 xenograft model, tumor growth and progression could be inhibited by iso-suillin. Body weight change and some vital organs toxicity was also roughly examined, no significant toxic effects of iso-suillin were shown (at a dose of 5 mg/kg for each administration). The in vitro and in vivo anti-tumor effects implied that iso-suillin may act as a tumor growth inhibitor, and its induction of p53 phosphorylation is pivotal for cell cycle arrest and apoptosis in A549 cells.
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- 2021
10. Preparation and characterization of intumescent flame retardant biodegradable poly(lactic acid) nanocomposites based on sulfamic acid intercalated layered double hydroxides
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Sheng Zhang, Xiaoyu Gu, Limin Li, Jun Sun, Hongfei Li, and Yongxin Yan
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Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Layered double hydroxides ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Limiting oxygen index ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Cone calorimeter ,Sulfamic acid ,engineering ,Char ,Composite material ,0210 nano-technology ,Intumescent ,Fire retardant - Abstract
A novel sulfamic acid intercalated MgAl-LDH (SA-LDH) was prepared by intercalating NH3SO3− into MgAl-layered double hydroxides (LDH), and it was then introduced into poly(lactic acid) (PLA) resin in association with intumescent flame retardant (IFR) by melt blending to prepare a flame-retardant biodegradable PLA composite. The effects of SA-LDH on the flame retardancy of PLA composites were characterized by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test (CONE). The results showed that the composite sample containing 19.0 wt% IFR and 1.0 wt% SA-LDH achieved the maximal LOI value of 48.7 %, passed the UL-94 V-0 rating, and significantly decreased the peak heat release rate from 306.3 kW/m2 of neat PLA to 58.1 kW/m2. Thermogravimetric analysis showed that both the thermal stability and the char formation were enhanced. The char morphology observation revealed that SA-LDH was beneficial to form dense and compact char layers. It was demonstrated that there existed a synergistic effect between IFR and SA-LDH in promoting the char formation and enhancing the fire resistance. The mechanical and crystallization properties were also tested and discussed.
- Published
- 2017
11. Pendant structure governed the selectivity of Pd2+ using disubstituted polyacetylenes with sulfur functions and the application of thiophanate-methyl detection
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Shanqing Li, Yongxin Yan, Ke Peng, Yan Feng, Linfeng Nie, Man Chen, Min Fang, Jun Jiang, and Xin Wang
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Chemistry ,Ligand ,Metals and Alloys ,02 engineering and technology ,Conjugated system ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,01 natural sciences ,Fluorescence ,Medicinal chemistry ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Acetylene ,Materials Chemistry ,Density functional theory ,Titration ,Electrical and Electronic Engineering ,Cyclic voltammetry ,0210 nano-technology ,Selectivity ,Instrumentation - Abstract
A series of disubstituted polyacetylenes-based fluorescent chemosensors for Pd2+ has been designed and synthesized. The optimization of sensing performance for Pd2+ ions is realized through modulating the coordination mode, type and number of coordination atoms in pendant groups. The receptor groups containing both N and S atoms (Poly [1-phenyl-2-[3-(2-pyridylmercapto)propyl]acetylene] (P2) and Poly [1-phenyl-2-[3-(5-methyl-1,3,4-thiadiazole-2-mercapto)propyl]acetylene] (P4)) can respond simultaneously for Pd2+ and Pt4+/2+ ions, and the only introduction of sulfur as the ligand atoms (Poly [1-phenyl-2-[3-(p-methylphenylthio)propyl]acetylene] (P1) and Poly [1-phenyl-2-[3-(2-Thienylthio)propyl]acetylene] (P3)) can exhibit high selectivity for Pd2+. P3 containing double sulfur atoms in pendants exhibits more high selectivity and sensitivity toward Pd2+ than that of P1 containing single sulfur atom. Aforementioned results were illustrated by fluorescence titration, Ksv fitting and cyclic voltammetry (CV) analysis. The emission of P3–Pd2+ complex can be turned on by the addition of thiophanate-methyl (TM) without the interference from other anions and pesticides. Thus, P3–Pd2+ complex can work as the novel Pd2+−mediated conjugated polymer-based fluorescent (CPF) chemosensors platform for thiophanate-methyl detection. The “on-off-on” sensing mechanism was supported by MALDI-TOF mass analysis, density functional theory (DFT) calculations and the association constants Ka fitting.
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- 2017
12. Copper ion-mediated glyphosate detection with N-heterocycle based polyacetylene as a sensing platform
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Shanqin Li, Gui Meifang, Yan Feng, Xin Wang, Yongxin Yan, Xinle Xiao, Liu Tingguo, Jun Jiang, and Tianbao Liu
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inorganic chemicals ,Metal ions in aqueous solution ,Triazole ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,Polyacetylene ,Magazine ,law ,Materials Chemistry ,Imidazole ,Organic chemistry ,Electrical and Electronic Engineering ,Instrumentation ,Detection limit ,Metals and Alloys ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Copper ,Fluorescence ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,0210 nano-technology ,Nuclear chemistry - Abstract
Two novel disubstituted polyacetylenes (TZP and PBP) with triazole and 2-(pyridin-2-yl)-1H-benzo[d]imidazole as the side groups, respectively, were successfully synthesized through using a post-functionalization strategy, and their fluorescence responses to metal ions and pesticides were investigated in detail. Strong emission from TZP and PBP could be efficiently quenched by a trace of Cu2+, through an electron or energy transfer process. The addition of Glyphosate (Glyp) to the solution of TZP/Cu2+ and PBP/Cu2+ complexes could recover the emission of TZP and PBP, and exhibit good “turn on” sensing signals for monitoring Glyp. These complex sensors had the high selectivity to Glyp without the interference from other anions and pesticides. The PBP/Cu2+ complex showed much higher sensitivity and a lower detection limit (8.0 × 10−8 M) for Glyp than that of TZP/Cu2+ complex. With the aid of PBP/Cu2+ complex, Glyp could be differed from other pesticides visually by its strong blue emission under the hand-held UV lamp, at the concentration as low as 1.0 × 10−5 M. This work provides a new strategy for the development of Glyp sensors.
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- 2017
13. The role of E2F1-topoIIβ signaling in regulation of cell cycle exit and neuronal differentiation of human SH-SY5Y cells
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Najing Zhou, Jing Chen, Cuili Cao, Junxia Zhao, Huixian Cui, Yongxin Yan, Yannan Xu, Shuo Han, Yunli Yan, Yanling Wang, Juan Zhao, and Fan Feng
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0301 basic medicine ,endocrine system ,Cancer Research ,SH-SY5Y ,Neurite ,Retinoic acid ,Tretinoin ,Biology ,Retinoblastoma Protein ,Cell Line ,03 medical and health sciences ,chemistry.chemical_compound ,E2F1 ,Humans ,Cyclin D1 ,Poly-ADP-Ribose Binding Proteins ,Promoter Regions, Genetic ,Molecular Biology ,Neurons ,Cell Cycle ,Cyclin-Dependent Kinase 4 ,Gene Expression Regulation, Developmental ,Promoter ,Cell Differentiation ,Cell Biology ,Cell cycle ,Phenotype ,Cell biology ,030104 developmental biology ,DNA Topoisomerases, Type II ,chemistry ,Phosphorylation ,biological phenomena, cell phenomena, and immunity ,Microtubule-Associated Proteins ,E2F1 Transcription Factor ,Developmental Biology ,Protein Binding ,Signal Transduction - Abstract
This study aims to test the role of E2F1-topoIIβ signaling in neuronal differentiation of SH-SY5Y cells. With retinoic acid (RA) induction, a high percentage of cells were found to be arrested at the G0/G1 phase, with decreased levels of cyclinD1, CDK4, phosphorylation status of pRb and E2F1, in addition to an elevated level of p27. The cells were shown to differentiate into neuronal phenotypes characterized by highly expressed neuronal markers, MAP2 and enriched topoIIβ, and remarkable neurite outgrowth. Exogenously forced E2F1 expression with a specific E2F1 plasmid led to suppression of topoIIβ expression and disruption of the neuronal differentiation of SH-SY5Y cells. On further examination using the ChIP assay, we found that E2F1 bound directly to the promoter region of topoIIβ, and its binding ability was inversely correlated with topoIIβ expression in response to RA induction. Thus, our findings suggest that E2F1-topoIIβ signaling may play a role in regulation of cell cycle exit and neuronal differentiation.
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- 2018
14. Key factors controlling the gas adsorption capacity of shale: A study based on parallel experiments
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Jijun Li, Xintong Yan, Xinwen Zhang, Yuanlin Meng, Yin Jianxin, Xiang Chen, Jingxiu Zhu, Yongxin Yan, Shuangfang Lu, Weiming Wang, Zhang Yanian, and Fangwen Chen
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chemistry.chemical_classification ,business.industry ,Mineralogy ,Langmuir adsorption model ,Pollution ,symbols.namesake ,Adsorption ,chemistry ,Geochemistry and Petrology ,Natural gas ,Specific surface area ,symbols ,Environmental Chemistry ,Organic matter ,Gas composition ,business ,Clay minerals ,Oil shale - Abstract
This article performed a series of parallel experiments with numerical modeling to reveal key factors affecting the gas adsorption capacity of shale, including shale quality, gas composition and geological conditions. Adsorption experiments for shales with similar OM types and maturities indicate that the OM is the core carrier for natural gas in shale, while the clay mineral has limited effect. The N 2 and CO 2 adsorption results indicate pores less than 3 nm in diameter are the major contributors to the specific surface area for shale, accounting for 80% of the total. In addition, micropores less than 2 nm in diameter are generated in large numbers during the thermal evolution of organic matter, which substantially increases the specific surface area and adsorption capacity. Competitive adsorption experiments prove that shale absorbs more CO 2 than CH 4 , which implies that injection CO 2 could enhance the CH 4 recovery, and further research into N 2 adsorption competitiveness is needed. The Langmuir model simulations indicate the shale gas adsorption occurs via monolayers. Geologically applying the adsorption potential model indicates that the adsorption capacity of shale initially increases before decreasing with increasing depth due to the combined temperature and pressure, which differs from the changing storage capacity pattern for free gases that gradually increase with increasing depth at a constant porosity. These two tendencies cause a mutual conversion between absorbed and free gas that favors shale gas preservation. During the thermal evolution of organic matter, hydrophilic NSO functional groups gradually degrade, reduce the shale humidity and increase the gas adsorption capacity. The shale quality, gas composition and geological conditions all affect the adsorption capacity. Of these factors, the clay minerals and humidity are less important and easily overshadowed by the other factors, such as organic matter abundance.
- Published
- 2015
15. Closed-form American Options Pricing Models on Foreign Assets
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Yongxin Yan
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Valuation of options ,Financial economics ,Economics ,General Medicine - Published
- 2015
16. Specificity protein 1 regulates topoisomerase IIβ expression in SH-SY5Y cells during neuronal differentiation
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Xia Liu, Hui Guo, Najing Zhou, Hongxia Sun, Shuo Han, Yunli Yan, Cuili Cao, Xueqian Chi, Yanling Wang, Yongxin Yan, Huixian Cui, Junxia Zhao, and Yannan Xu
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Cellular and Molecular Neuroscience ,SH-SY5Y ,Neurite ,Transcription (biology) ,Gene expression ,CAAT box ,Promoter ,Biology ,Chromatin immunoprecipitation ,Molecular biology ,Transcription factor - Abstract
Topoisomerase IIβ (top IIβ) is a nuclear enzyme with an essential role in neural development. The regulation of top IIβ gene expression during neural differentiation is poorly understood. Functional analysis of top IIβ gene structure displayed a GC box sequence in its transcription promoter, which binds the nuclear transcription factor specificity protein 1 (Sp1). Sp1 regulates gene expression via multiple mechanisms and is essential for early embryonic development. This study seeks to determine whether Sp1 regulates top IIβ gene expression during neuronal differentiation. For this purpose, human neuroblastoma SH-SY5Y cells were induced to neuronal differentiation in the presence of all-trans retinoic acid (RA) for 5 days. After incubation with 10 μM RA for 3–5 days, a majority of the cells exited the cell cycle to become postmitotic neurons, characterized by the presence of longer neurite outgrowths and expression of the neuronal marker microtubule-associated protein-2 (MAP2). Elevated Sp1 and top IIβ mRNA and protein levels were detected and found to be positively correlated with the differentiation stage. Chromatin immunoprecipitation assay demonstrated an increased recruitment of Sp1 to the top IIβ promoter after RA treatment. Mithramycin A, a compound that interferes with Sp1 binding to GC-rich DNA sequences, downregulated the expression of top IIβ, resulting in reduced expression of MAP2 and decreased neurite length compared with the control group. Our results indicate that Sp1 regulates top IIβ expression by binding to the GC box of the gene promoter during neuronal differentiation in SH-SY5Y cells. © 2014 Wiley Periodicals, Inc.
- Published
- 2014
17. Controllable fabrication and sensitive detection based on SERS substrates with Au nanocubes coated Fe3O4
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Yongxin Yan, Xin Wang, and Wenya Cai
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symbols.namesake ,Fabrication ,Materials science ,Mechanics of Materials ,Mechanical Engineering ,symbols ,General Materials Science ,Nanotechnology ,Condensed Matter Physics ,Raman spectroscopy ,Fe3o4 nanoparticles ,Raman scattering - Abstract
Au nanocubes (NCs) coated Fe3O4 nanoparticles (Fe3O4/Au NPs) were designed and fabricated controllably via a facile method. The diameter of Au NCs in the surface of Fe3O4 was 65 nm, considering the appropriate size for Au NPs as surface-enhanced Raman scattering (SERS) substrates, which makes the Fe3O4/Au NPs used for pesticide analysis with high sensitivity.
- Published
- 2014
18. Immunohistochemical investigation of topoIIβ, H3K27me3 and JMJD3 expressions in medulloblastoma
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Cuili Cao, Huixian Cui, Jing Chen, Shou Han, Yanling Wang, Yunli Yan, Shuang Liu, Yongxin Yan, Juan Zhao, Junxia Zhao, Xiaofen Zhou, Najing Zhou, and Yannan Xu
- Subjects
0301 basic medicine ,Male ,Pathology ,medicine.medical_specialty ,Cerebellum ,Jumonji Domain-Containing Histone Demethylases ,Adolescent ,Neuronal differentiation ,Biology ,Pathology and Forensic Medicine ,Histones ,03 medical and health sciences ,medicine ,Biomarkers, Tumor ,Humans ,Epigenetics ,Cerebellar Neoplasms ,Child ,Psychological repression ,Medulloblastoma ,Topoisomerase ,Cell Differentiation ,Cell Biology ,medicine.disease ,Molecular biology ,Immunohistochemistry ,Staining ,030104 developmental biology ,medicine.anatomical_structure ,DNA Topoisomerases, Type II ,Child, Preschool ,biology.protein ,Female - Abstract
Topoisomerase IIβ (topoIIβ) is a nuclear enzyme specifically expressed in neurons, and plays an important role in the development of the cerebellum. To date, the expression of topoIIβ protein in medulloblastoma (MB) has not been investigated. In this study, 16 MB specimens including 10 classical subtypes of MB and 6 desmoplastic subtypes of MB (DMB), along with 5 normal cerebellum samples, were obtained from clinics. With immunohistochemical staining, prominently expressed topoIIβ was seen in normal cerebellar tissues, while there was no or less pronounced staining in classical MB cells. Interestingly, on comparing topoIIβ expression in different regions of DMB samples, relatively high levels of topoIIβ were revealed within nodules composed of differentiated neurocytic cells, which are known to predict a favorable clinical outcome for MB. We also examined the expression of two epigenetic factors, H3K27me3 and JMJD3 in the different tissues. Very high levels of H3K27me3 were found in all MB samples, except the intranodules of DMB, where JMJD3 expression was more prominent. Furthermore, a negative correlation between topoIIβ and H3K27me3 in MB was revealed in this study. Thus, our data primarily indicate that topoIIβ can be used to estimate neuronal differentiation in MB, and may serve as a target for improving the survival rates for this condition. We speculate that H3K27me3 repression of topoIIβ at the transcriptional level may occur, although this needs to be verified using larger numbers of MB samples in future experiments.
- Published
- 2016
19. Synthesis and nonlinear optical properties of polyacetylenes containing oxadiazole and thiophene pendant groups with high thermal stability
- Author
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Xinyan Su, Yinglin Song, Yongxin Yan, Hongyao Xu, Xin Wang, Liwu Qian, and Tianbao Liu
- Subjects
chemistry.chemical_classification ,Polymers and Plastics ,Organic Chemistry ,Oxadiazole ,Polymer ,Carbon-13 NMR ,Polyacetylene ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Materials Chemistry ,Proton NMR ,Copolymer ,Thiophene ,Thermal stability - Abstract
A series of random copolymers poly(3-ethynylthiophene)-copoly(2-(4-decyloxyphenyl)-5-(4-ethynylphenyl)-1,3,4-oxadiazole) with different oxadiazole content (P2–P4) and homopolymer poly(3-ethynylthiophene) (P1) as well as poly(2-(4-decyloxyphenyl)-5-(4-ethynylphenyl)-1,3,4-oxadiazole) (P5) were prepared. The copolymers (P2–P4) are completely soluble in common organic solvents. The structures and properties of all polymers were characterized and evaluated by FTIR, 1H NMR, 13C NMR, TGA, UV, PL, GPC, and nonlinear optical (NLO) analyses. The incorporation of diaryl-oxadiazole into polyacetylene-containing thiophene significantly endows copolymers with higher thermal stability, which may origin from the synergetic effect of the “jacket effect” of diaryl-oxadiazole units and the effect of retarding or eliminating a few 6π-electrocycliaztion proceeds of oxadiazole-containing polyacetylene due to the hindrance of thiophene units. When the copolymer (P3) posses more regular alternating thiophene pendants and oxadiazole pendants arrangement along the polymer backbone, it shows good thermal stability (Td up to 388 °C) and larger third-order nonlinear optical susceptibility (χ(3) up to 11.0 × 10−11 esu). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
- Published
- 2010
20. High activity of Pd–In2O3/CNTs electrocatalyst for electro-oxidation of ethanol
- Author
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Huashui Lin, Zhao-Wu Tian, Longwu Zha, Daobao Chu, Yuanyuan Hou, Jianguo He, Shuxi Wang, Yongxin Yan, and Jian Wang
- Subjects
Chemistry ,Process Chemistry and Technology ,Foundation (engineering) ,High activity ,Nanotechnology ,General Chemistry ,Electrocatalyst ,Catalysis - Abstract
National Natural Science Foundation of China [20476001]; Natural Science Foundation of Anhui province [070414160]
- Published
- 2009
21. Tetramethylpyrazine induces SH-SY5Y cell differentiation toward the neuronal phenotype through activation of the PI3K/Akt/Sp1/TopoIIβ pathway
- Author
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Junxia Zhao, Yanling Wang, Zhi-qiang Jia, Huixian Cui, Yunli Yan, Sheng-jie Yao, Yannan Xu, Cuili Cao, Yongxin Yan, Najing Zhou, Juan Zhao, and Shuo Han
- Subjects
Transcriptional Activation ,Histology ,SH-SY5Y ,Neurite ,Sp1 Transcription Factor ,Cellular differentiation ,Drug Evaluation, Preclinical ,Gene Expression ,Biology ,Pathology and Forensic Medicine ,Phosphatidylinositol 3-Kinases ,Cell Line, Tumor ,Humans ,Promoter Regions, Genetic ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Neurons ,Sp1 transcription factor ,Cell Biology ,General Medicine ,G1 Phase Cell Cycle Checkpoints ,Cell biology ,DNA-Binding Proteins ,DNA Topoisomerases, Type II ,Phenotype ,CCAAT-Binding Factor ,Pyrazines ,Cell Transdifferentiation ,Phosphorylation ,Signal transduction ,Protein Processing, Post-Translational ,Proto-Oncogene Proteins c-akt ,Protein Binding ,Signal Transduction - Abstract
Tetramethylpyrazine (TMP) is an active compound extracted from the traditional Chinese medicinal herb Chuanxiong. Previously, we have shown that TMP induces human SH-SY5Y neuroblastoma cell differentiation toward the neuronal phenotype by targeting topoisomeraseIIβ (TopoIIβ), a protein implicated in neural development. In the present study, we aimed to elucidate whether the transcriptional factors specificity protein 1 (Sp1) and nuclear factor Y (NF-Y), in addition to the upstream signaling pathways ERK1/2 and PI3K/Akt, are involved in modulating TopoIIβ expression in the neuronal differentiation process. We demonstrated that SH-SY5Y cells treated with TMP (80μM) terminally differentiated into neurons, characterized by increased neuronal markers, tubulin βIII and microtubule associated protein 2 (MAP2), and increased neurite outgrowth, with no negative effect on cell survival. TMP also increased the expression of TopoIIβ, which was accompanied by increased expression of Sp1 in the differentiated neuron-like cells, whereas NF-Y protein levels remained unchanged following the differentiation progression. We also found that the phosphorylation level of Akt, but not ERK1/2, was significantly increased as a result of TMP stimulation. Furthermore, as established by chromatin immunoprecipitation (ChIP) assay, activation of the PI3K/Akt pathway increased Sp1 binding to the promoter of the TopoIIβ gene. Blockage of PI3K/Akt was shown to lead to subsequent inhibition of TopoIIβ expression and neuronal differentiation. Collectively, the results indicate that the PI3K/Akt/Sp1/TopoIIβ signaling pathway is necessary for TMP-induced neuronal differentiation. Our findings offer mechanistic insights into understanding the upstream regulation of TopoIIβ in neuronal differentiation, and suggest potential applications of TMP both in neuroscience research and clinical practice to treat relevant diseases of the nervous system.
- Published
- 2015
22. Effect of dexmedetomidine as an adjuvant to ropivacaine for wound infiltration in patients undergoing open gastrectomy
- Author
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Liang Tian, Jiying Feng, Hengfei Luan, Xiaoping Gu, Yong Wu, Yongxin Yan, Zhibin Zhao, Xiaobao Zhang, and Pin Zhu
- Subjects
medicine.medical_specialty ,Visual analogue scale ,Ropivacaine ,business.industry ,medicine.medical_treatment ,Analgesic ,030208 emergency & critical care medicine ,General Medicine ,law.invention ,Surgery ,Sufentanil ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,030202 anesthesiology ,law ,Anesthesia ,medicine ,Gastrectomy ,medicine.symptom ,Dexmedetomidine ,business ,Postoperative nausea and vomiting ,medicine.drug - Abstract
OBJECTIVES The primary objective of this study was to investigate whether dexmedetomidine could potentiate the analgesic efficacy of ropivacaine, when added to ropivacaine for wound infiltration in patients undergoing open gastrectomy. METHODS Fifty patients scheduled for open gastrectomy were divided into 2 equal groups that were received wound infiltration using 20 mL 0.3% ropivacaine plus 2 mL normal saline (group R) or 20 mL 0.3% ropivacaine plus 2 mL 1.0 μg/kg dexmedetomidine (group DR). Visual analogue scale (VAS) pain score, patient-controlled analgesia (PCA) pump press number, sufentanil consumption, postoperative nausea and vomiting (PONV), and wound healing score were recorded. RESULTS The VAS pain score were comparable between the 2 groups at the observation time points (P > .05), PCA pump press number and sufentanil consumption were higher in group R than that in group DR at 0 to 2, 2 to 4, 4 to 6 time intervals (P .05), meanwhile, the 24 hours total sufentanil consumption was also higher in group R than that in group DR (90.4 ± 20.5 vs 79.2 ± 9.4) (P .05). CONCLUSIONS Dexmedetomidine as an adjuvant to ropivacaine for wound infiltration promoted the analgesic efficacy of ropivacaine, reduced sufentanil consumption, and had no effect on wound healing; it could be as an ideal adjuvant which could potentiate the analgesic efficacy of local anesthetics.
- Published
- 2017
23. Specificity protein 1 regulates topoisomerase IIβ expression in SH-SY5Y cells during neuronal differentiation
- Author
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Hui, Guo, Cuili, Cao, Xueqian, Chi, Junxia, Zhao, Xia, Liu, Najing, Zhou, Shuo, Han, Yongxin, Yan, Yanling, Wang, Yannan, Xu, Yunli, Yan, Huixian, Cui, and Hongxia, Sun
- Subjects
Neurons ,Chromatin Immunoprecipitation ,Sp1 Transcription Factor ,Cell Cycle ,Cell Differentiation ,Tretinoin ,DNA-Binding Proteins ,Gene Expression Regulation, Neoplastic ,Neuroblastoma ,DNA Topoisomerases, Type II ,Keratolytic Agents ,Cell Line, Tumor ,Neurites ,Humans ,RNA, Messenger ,Cell Division ,Protein Binding - Abstract
Topoisomerase IIβ (top IIβ) is a nuclear enzyme with an essential role in neural development. The regulation of top IIβ gene expression during neural differentiation is poorly understood. Functional analysis of top IIβ gene structure displayed a GC box sequence in its transcription promoter, which binds the nuclear transcription factor specificity protein 1 (Sp1). Sp1 regulates gene expression via multiple mechanisms and is essential for early embryonic development. This study seeks to determine whether Sp1 regulates top IIβ gene expression during neuronal differentiation. For this purpose, human neuroblastoma SH-SY5Y cells were induced to neuronal differentiation in the presence of all-trans retinoic acid (RA) for 5 days. After incubation with 10 μM RA for 3-5 days, a majority of the cells exited the cell cycle to become postmitotic neurons, characterized by the presence of longer neurite outgrowths and expression of the neuronal marker microtubule-associated protein-2 (MAP2). Elevated Sp1 and top IIβ mRNA and protein levels were detected and found to be positively correlated with the differentiation stage. Chromatin immunoprecipitation assay demonstrated an increased recruitment of Sp1 to the top IIβ promoter after RA treatment. Mithramycin A, a compound that interferes with Sp1 binding to GC-rich DNA sequences, downregulated the expression of top IIβ, resulting in reduced expression of MAP2 and decreased neurite length compared with the control group. Our results indicate that Sp1 regulates top IIβ expression by binding to the GC box of the gene promoter during neuronal differentiation in SH-SY5Y cells.
- Published
- 2014
24. Synthesis and optical properties of poss-based oxadiazole nanohybrids with three-dimensional molecular conjugated structure
- Author
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Feng Yan, Xin Wang, Tianbao Liu, Yongxin Yan, Xinyan Su, and Jun Wang
- Subjects
Photoluminescence ,Materials science ,Polymers and Plastics ,Oxadiazole ,General Chemistry ,Conjugated system ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,chemistry ,Elemental analysis ,Heck reaction ,Polymer chemistry ,Materials Chemistry ,Cyclic voltammetry ,Fourier transform infrared spectroscopy ,Hybrid material - Abstract
A series of oxadiazole-containing molecular hybrid materials with three-dimensional structure (P1–P3) was prepared by Heck reaction based on the octavinylsilsesquioxane. All resultant hybrid materials are soluble in common organic solvents and possess good film-forming property. Their structures and properties were characterized and evaluated by FTIR, 1H-NMR, 13C-NMR, 29Si-NMR, MALDI-TOF, UV–vis, photoluminescence (PL), cyclic voltammetry, and elemental analysis (EA). The results showed that the substituted arm numbers of hybrids (P2 and P3) with pushing electron groups were efficiently controlled. Moreover, the hybrids possessed a steady blue emission and good electron-injecting property in film. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40246.
- Published
- 2013
25. Profiling of differentially expressed microRNAs in premature ovarian failure in an animal model
- Author
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Haixue Kuang, Pengling Ge, Ji Li, Jiaming Xie, Dongwei Han, and Yongxin Yan
- Subjects
endocrine system diseases ,Endocrinology, Diabetes and Metabolism ,CCL2 ,Primary Ovarian Insufficiency ,Bioinformatics ,Rats, Sprague-Dawley ,Endocrinology ,microRNA ,medicine ,Animals ,Humans ,Gene Regulatory Networks ,biology ,Microarray analysis techniques ,Gene Expression Profiling ,Obstetrics and Gynecology ,medicine.disease ,Microarray Analysis ,PLA2G4A ,female genital diseases and pregnancy complications ,Premature ovarian failure ,Rats ,Gene expression profiling ,Disease Models, Animal ,MicroRNAs ,Cancer research ,biology.protein ,Female ,DNA microarray ,Hormone - Abstract
Premature ovarian failure (POF) contributes to amenorrhoea, infertility, early onset of menostasia and osteoporosis. This study profiled differentially expressed miRNAs for association with POF development. Ovarian tissue samples from 4-vinylcyclohexene diepoxide (VCD)-induced rat POF and normal rats were profiled for differentially expressed miRNAs using miRNA microarrays. A total of 63 miRNAs were up-regulated and 20 miRNAs were down-regulated in rat POF tissues versus the control tissues. qRT-PCR verified some of these altered miRNAs, i.e. miR-29a and miR-144 were down-regulated in POF tissues, which may target expression of PLA2G4A that is involved in prostaglandin biosynthesis, whereas miR-27b and miR-190 were up-regulated in POF tissues by negative control of PAPPA and CCL2 expression, respectively, both of which have been shown to relate to response to hormone stimulus. Moreover, the up-regulated miR-151 and miR-672 can also target expression of TNFSF10 and FNDC1, which have been shown to positively regulate cell apoptosis. Profiling of differentially expressed miRNAs in POF provided a novel insight into the molecular events involving the role of miRNAs in POF development with specific emphasis upon miR-27b, miR-190, miR-151, miR-672, miR-29a and miR-144.
- Published
- 2013
26. Detecting and Correcting the Index of DAE by the Combinatorial Relaxation Algorithm
- Author
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Xuesong Wu, Xiaolei Zhang, Jianwen Cao, and Yongxin Yan
- Subjects
Modeling and simulation ,Reduction (complexity) ,Index (economics) ,Differential equation ,Computer science ,ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION ,Stability (learning theory) ,Algorithm design ,Algorithm ,Differential algebraic equation ,Modelica - Abstract
The mathematical modeling and simulation based on the Modelica language usually gets a high-index differential-algebraic equation (DAE) system. The structural index reduction algorithms can serve as a fast method to reduce such high-indexed issues. In order to solve the failure of the structural index reduction algorithms in some cases, the combinatorial relaxation algorithm is analyzed and studied. Finally, the result of an example shows the combinatorial relaxation algorithm is an effective way to improve the stability of the index reduction algorithms based on the structural index of DAE.
- Published
- 2011
27. A new integrated control algorithm for IEEE 802.11G standards
- Author
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Yongxin Yan, Jing Tu, Bainan Xia, and Qian Liu
- Subjects
IEEE 802 ,Exponential backoff ,Computer science ,business.industry ,media_common.quotation_subject ,Fidelity ,Throughput ,Reduction (complexity) ,Transmission (telecommunications) ,Wireless ,business ,Communication channel ,Computer network ,media_common - Abstract
Wi-Fi (Wireless Fidelity) mainly adopts IEEE 802.11g standards. And a binary exponential backoff algorithm is adopted to prevent channel collision, which also introduces reduction of the performance of the network. In this paper, an integrated control mechanism (ICM) is proposed which combines a centrally controlled approach and a distributed access mechanism to control the behavior of the system. Through this mechanism, backoff is eliminated from transmission mode, which can significantly enhance the performance of the system. Through theoretical analysis and simulation, the new mechanism can improve the throughput and reduce delay and packet loss rate. According to the results of simulation, with ICM, the throughput can have an improvement of 83.3% and the packet loss rate remains at 0 under appropriate conditions.
- Published
- 2011
28. Research and analysis of the Virtual Reality with FLARToolKit
- Author
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Yongxin Yan and Xiaolei Zhang
- Subjects
Identification (information) ,Multimedia ,Computer science ,business.industry ,Augmented reality ,Sample (statistics) ,Virtual reality ,Broadcasting ,computer.software_genre ,business ,Frame rate ,Virtual studio ,computer - Abstract
Currently most technologies used by virtual studio systems are extended applications of Virtual Reality (VR) technologies. But for small TV stations and web stations, virtual studio based on traditional VR is so expensive while the FLARToolKit technology used by Augmented Reality (AR) technologies is their top option. However, the calculation speed of FLARToolKit is a little slow and the frame rate is very difficult to reach the live broadcasting video level. My improvements are to apply adaptive thresholds, use sample blurring and change identification frequency, which solves the shortcomings and makes the Virtual Studio faster and better.
- Published
- 2011
29. Application of the combinatorial relaxation algorithm in index reduction method
- Author
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Xiaolei Zhang and Yongxin Yan
- Subjects
Reduction (complexity) ,Modeling and simulation ,Index (economics) ,ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION ,Stability (learning theory) ,Key (cryptography) ,Computer Science::Symbolic Computation ,Algorithm design ,Relaxation algorithm ,Algorithm ,Differential algebraic equation ,Mathematics - Abstract
The mathematical modeling and simulation usually gets a high-index differential-algebraic equation (DAE) system. The structural index reduction algorithms can reduce high-index DAE to low-index DAE. In order to solve the failure of the structural index reduction algorithms in some cases, the authors firstly analyze the combinatorial relaxation algorithm. Then some key algorithms in the implementation of the combinatorial relaxation algorithm are analyzed. Finally, the result of an example shows that the combinatorial relaxation algorithm is an effective way to improve the stability and suitability of the index reduction algorithm based on structural index in DAE.
- Published
- 2011
30. Bandwidth-efficient contention-free mechanism for wireless networks
- Author
-
Yongxin Yan, Kok Keong Chai, Jing Tu, and Qian Liu
- Subjects
Wi-Fi array ,Computer science ,Wireless network ,business.industry ,Node (networking) ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Frame (networking) ,Bandwidth (computing) ,Network performance ,Throughput ,Distributed coordination function ,business ,Computer network - Abstract
The employment of Distributed Coordination Function has caused a waste of bandwidth and time, which leading to unsatisfactory network performance of wireless LANs. In our proposed mechanism, access points (APs) are used for determining which terminal to transmit a frame according to a sorted node list, which avoids the collision and backoff. To guarantee the practicality of the proposed mechanism, changes are only made to APs while all terminals act in the same way as in existing mechanism. The realization is through flexible use and modification of some control and management frames. Simulation results demonstrate that the proposed mechanism can improve network performance of throughput and delay.
- Published
- 2011
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