297 results on '"Yongfeng Chen"'
Search Results
202. Different Transcription Factors Regulate nestin Gene Expression during P19 Cell Neural Differentiation and Central Nervous System Development
- Author
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Naihe Jing, Li Liu, Wei Bian, Zhigang Jin, Leping Cheng, Guoliang Xu, and Yongfeng Chen
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Neural Tube ,Mice, Transgenic ,Nerve Tissue Proteins ,Enhancer RNAs ,Chick Embryo ,Biology ,Response Elements ,Steroidogenic Factor 1 ,Nervous System ,Biochemistry ,Nestin ,Mice ,Intermediate Filament Proteins ,SOX2 ,Cell Line, Tumor ,medicine ,Animals ,Humans ,Transcription, Chromatin, and Epigenetics ,Enhancer ,Molecular Biology ,Transcription factor ,Neurons ,Regulation of gene expression ,Mice, Inbred ICR ,SOXB1 Transcription Factors ,Stem Cells ,Neural tube ,Gene Expression Regulation, Developmental ,Cell Biology ,Embryo, Mammalian ,Molecular biology ,Neural stem cell ,Rats ,DNA-Binding Proteins ,medicine.anatomical_structure ,POU Domain Factors ,embryonic structures ,Chickens ,Octamer Transcription Factor-1 ,Transcription Factors - Abstract
Nestin is a molecular marker for neural progenitor cells. Rat and human nestin genes possess a central nervous system-specific enhancer within their second introns. However, the transcription factors that bind to the nestin enhancer have not been fully elucidated. Here, we show that the second intron of the mouse nestin gene is sufficient to drive reporter gene expression in the developing nervous system. The core sequence of this central nervous system-specific enhancer localizes to the 3′ 320-bp region. The cis-elements for Sox and POU family transcription factors and the hormone-responsive element are essential for nestin expression during embryonic carcinoma P19 cell neural differentiation and in the developing chick neural tube. Interestingly, different transcription factors bind to the nestin enhancer at different stages of P19 cell neural differentiation and central nervous system development. Sox2 and SF1 may mediate basal nestin expression in undifferentiated P19EC cells, whereas Sox2, Brn1, and Brn2 bind to the enhancer in P19 neural progenitor cells. Similarly, in vivo, Oct1 binds to the nestin enhancer in embryonic day 8.5 (E8.5) mouse embryos, and Oct1, Brn1, and Brn2 bind to this enhancer in E10.5 and E12.5 mouse embryos. Our studies therefore suggest a temporal coordination of transcription factors in determining nestin gene expression.
- Published
- 2009
203. Hydrogen Peroxide Promotes Aβ Production through JNK-dependent Activation of γ-Secretase
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Chengyong Shen, Ting Zhang, Huaqing Liu, Naihe Jing, Anning Lin, Kejing Zhang, and Yongfeng Chen
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Male ,Genetically modified mouse ,Small interfering RNA ,MAP Kinase Kinase 4 ,Models, Biological ,Biochemistry ,Presenilin ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Alzheimer Disease ,Amyloid precursor protein ,medicine ,Animals ,Humans ,Senile plaques ,Enzyme Inhibitors ,Molecular Biology ,Aged ,030304 developmental biology ,Aged, 80 and over ,0303 health sciences ,biology ,Mechanisms of Signal Transduction ,P3 peptide ,Brain ,Hydrogen Peroxide ,Cell Biology ,medicine.disease ,Cell biology ,biology.protein ,Female ,Amyloid Precursor Protein Secretases ,Alzheimer's disease ,Proto-Oncogene Proteins c-akt ,Amyloid precursor protein secretase ,030217 neurology & neurosurgery - Abstract
Accumulation of senile plaques composed of amyloid beta-peptide (Abeta) is a pathological hallmark of Alzheimer disease (AD), and Abeta is generated through the sequential cleavage of amyloid precursor protein (APP) by beta- and gamma-secretase. Although oxidative stress has been implicated in the AD pathogenesis by inducing Abeta production, the underlying mechanism remains elusive. Here we show that the pro-oxidant H(2)O(2) promotes Abeta production through c-Jun N-terminal kinase (JNK)-dependent activation of gamma-secretase. Treatment with H(2)O(2) induced significant increase in the levels of intracellular and secreted Abeta in human neuroblastoma SH-SY5Y cells. Although gamma-secretase-mediated cleavage of APP or C99 was enhanced upon H(2)O(2) treatment, expression of APP or its alpha/beta-secretase-mediated cleavage was not affected. Silencing of the stress-activated JNK by small interfering RNA or the specific JNK inhibitor SP600125 reduced H(2)O(2)-induced gamma-secretase-mediated cleavage of APP. JNK activity was augmented in human brain tissues from AD patients and active JNK located surrounding the senile plaques in the brain of AD model mouse. Our data suggest that oxidative stress-activated JNK may contribute to senile plaque expansion through the promotion of gamma-secretase-mediated APP cleavage and Abeta production.
- Published
- 2008
204. Experimental investigation on internal offset crack of PMMA beam using caustics
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Yaodong Xue, Yongfeng Cheng, Qing Li, Weisheng Du, and Wenlong Xu
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Caustics ,Stress intensity factor ,Internal offset crack ,Dynamic failure ,Optical measurement ,Polymers and polymer manufacture ,TP1080-1185 - Abstract
In this paper, the dynamic stress intensity factor (DSIF) at the crack tip of a PMMA beam containing an internal offset crack under impact loading was investigated by using a transmission digital caustic test system combined with high-speed camera. Firstly, the stress intensity factor, as well as velocity, of the mixed-mode crack tip under static and dynamic loading were derived based on the transmission caustic method; secondly, a drop hammer loading test was conducted on the different specimens with biased cracks in the beam using the transmission caustic test system to obtain the dynamic fracture mechanics parameters of internal crack initiation and expansion; then, the crack initiation angle and expansion path analysis of the impact-generated expansion cracks were performed based on the theoretical analysis and the differences between the fracture process and that of the specimens containing internal symmetric cracks were discussed. The results show that the different locations of the internal off-set cracks make the stress redistribution process inside the beam and the stress state at the crack tip during the crack extension process different, and the fracture process and fracture mechanics parameters are different from those of the specimens with internal symmetric cracks, the results of the caustic test are in good agreement with the numerical analysis. The research results can provide guidance for the study of the fracture process of brittle materials such as PMMA containing internal defects.
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- 2023
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205. Effect of an educational intervention on parental readiness for premature infant discharge from the neonatal intensive care units
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Jinbing Bai, Yongfeng Chen, and Jun Zhang
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Adult ,Male ,Parents ,medicine.medical_specialty ,Pediatrics ,Group based ,China ,Care setting ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Child Rearing ,030225 pediatrics ,Intervention (counseling) ,Intensive care ,Health care ,medicine ,Humans ,Young adult ,General Nursing ,030504 nursing ,Child rearing ,Parenting ,business.industry ,Moderate level ,Infant, Newborn ,Middle Aged ,Patient Discharge ,Caregivers ,Family medicine ,Female ,0305 other medical science ,business ,Infant, Premature - Abstract
Aim To examine the effect of an educational intervention on parental readiness for premature infant discharge from neonatal intensive care units. Background Low readiness for discharge can result in negative healthcare outcomes for infants and their parents. However, few studies have examined the effect of discharge education programmes on parental readiness for premature infant discharge in Chinese critical care settings. Design A quasi-experimental study. Methods Between October 2011–March 2012, 154 parents of premature infants were recruited from neonatal intensive care units of two tertiary hospitals in Central China. These parents were assigned to either the intervention or control group based on their entry order. Parents in the intervention group received two sessions of 60-minute discharge education along with hospital routine care; parents in the control group only received hospital routine care. Parental readiness for discharge and quality of discharge education were assessed on the day of infant discharge from neonatal intensive care units. Independent samples t-test and linear regression were used to analyse the data. Results Parental readiness for premature infant discharge was in the moderate level. Independent samples t-test showed that both mean scores of parental discharge readiness and discharge teaching quality from the intervention group were significantly higher than those in the control group. Linear regression analysis showed that discharge teaching quality explained 39·7% of the variance in parental readiness for premature infant discharge. Conclusion Discharge education can improve parental readiness for premature infant discharge. Quality of discharge teaching can significantly predict parental readiness for premature infant discharge.
- Published
- 2015
206. TNF-α-induced programmed cell death in the pathogenesis of acquired aplastic anemia
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Zhongmin Wu, Xin-Jing Luo, Cong Xie, Zhiqiang Zhao, Zhenyou Zou, Yong Liang, and Yongfeng Chen
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Programmed cell death ,business.industry ,Tumor Necrosis Factor-alpha ,Necroptosis ,medicine.medical_treatment ,Cell ,Anemia, Aplastic ,Inflammation ,Apoptosis ,Hematology ,Receptors, Tumor Necrosis Factor ,Hematopoiesis ,Haematopoiesis ,medicine.anatomical_structure ,Cytokine ,Immunology ,Medicine ,Animals ,Humans ,Bone marrow ,medicine.symptom ,business ,Intracellular - Abstract
The mechanism of acquired aplastic anemia (AA), a bone marrow hematopoiesis failure disease, has not been fully understood. TNF-α is a pleiotropic cytokine involved in cell proliferation, differentiation and death, and inflammation through binding to specific receptors on cell membranes. Aberrant secretion of TNF-α contributes to a number of human diseases, including tumor development and inflammation. TNF-α is also an important negative regulator of hematopoiesis. Over-expression of TNF-α not only directly inhibits the proliferation and differentiation of hematopoietic cells, but also initiates the intracellular death pathway to induce hematopoietic cell death, leading to bone marrow hematopoiesis failure. In this review, we summarize the mechanisms underlying extrinsic apoptosis and necroptosis of hematopoietic cells induced by TNF-α, and discuss the role of TNF-α-induced programmed cell death in the pathogenesis of acquired AA.
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- 2015
207. Research on Data Transmission Method Based 4G in Platform
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Min Qin, Yongfeng Chen, and Ningxia Yang
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Computer science ,business.industry ,Real-time computing ,business ,Computer network ,Data transmission - Published
- 2015
208. Outage probability analysis of a MC-DS-CDMA system with variable repetition code rate and spreading factor
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Elvino S. Sousa and Yongfeng Chen
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Computer Networks and Communications ,Computer science ,business.industry ,Code division multiple access ,Repetition code ,Code rate ,Subcarrier ,Spread spectrum ,Bit rate ,Fading ,Electrical and Electronic Engineering ,Telecommunications ,business ,Algorithm ,Energy (signal processing) ,Computer Science::Information Theory ,Diversity scheme - Abstract
In the multicarrier direct-sequence code-division multiple access with repetition code system, decreasing the code rate can result in greater frequency diversity. However, to keep the same transmit bit rate, the spreading factor in each subcarrier needs to be reduced. In this paper, we use the outage probability as a criterion for these two system parameters' design. We first examine the condition on code rate for the uncorrelated fading channel assumption. The system performance is derived and the outage probability is obtained in closed forms for equal and unequal transmit bit energy scenarios. The relation between the spreading factor and the rate of the repetition code is investigated by observing the outage probability equation
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- 2006
209. Microtubule affinity-regulating kinase 2 functions downstream of the PAR-3/PAR-6/atypical PKC complex in regulating hippocampal neuronal polarity
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H. Piwnica-Worms, Jun-Ge Zhu, Huan-Huan Hu, Q. J. Wang, Gerard Drewes, Yongfeng Chen, Pengchun Yu, and Z. G. Luo
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Neurite ,Nerve Tissue Proteins ,tau Proteins ,Protein Serine-Threonine Kinases ,Biology ,Hippocampus ,Cell Line ,Microtubule ,Cell polarity ,Animals ,Humans ,Phosphorylation ,Protein kinase A ,Protein Kinase C ,Protein kinase C ,Neurons ,Multidisciplinary ,Cell Polarity ,Proteins ,Biological Sciences ,Rats ,Cell biology ,Protein kinase domain ,Mutation ,Ectopic expression ,Mitogen-Activated Protein Kinases ,Carrier Proteins ,Protein Binding - Abstract
The PAR-3/PAR-6/atypical PKC (aPKC) complex is required for axon–dendrite specification of hippocampal neurons. However, the downstream effectors of this complex are not well defined. In this article, we report a role for microtubule affinity-regulating kinase (MARK)/PAR-1 in axon–dendrite specification. Knocking down MARK2 expression with small interfering RNAs induced formation of multiple axon-like neurites and promoted axon outgrowth. Ectopic expression of MARK2 caused phosphorylation of tau (S262) and led to loss of axons, and this phenotype was rescued by expression of PAR-3, PAR-6, and aPKC. In contrast, the polarity defects caused by an MARK2 mutant (T595A), which is not responsive to aPKC, were not rescued by the PAR-3/PAR-6/aPKC complex. Moreover, polarity was abrogated in neurons overexpressing a mutant of MARK2 with a deleted kinase domain but an intact aPKC-binding domain. Finally, suppression of MARK2 rescued the polarity defects induced by a dominant-negative aPKC mutant. These results suggest that MARK2 is involved in neuronal polarization and functions downstream of the PAR-3/PAR-6/aPKC complex. We propose that aPKC in complex with PAR-3/PAR-6 negatively regulates MARK(s), which in turn causes dephosphorylation of microtubule-associated proteins, such as tau, leading to the assembly of microtubules and elongation of axons.
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- 2006
210. Second Intron of Mouse Nestin Gene Directs its Expression in Pluripotent Embryonic Carcinoma Cells through POU Factor Binding Site
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Li Liu, Leping Cheng, Naihe Jing, Wei Bian, Kejing Zhang, Yongfeng Chen, Hua Zhong, and Zhigang Jin
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Pluripotent Stem Cells ,Cellular differentiation ,Biophysics ,Nerve Tissue Proteins ,Biology ,Biochemistry ,Nestin ,Mice ,Intermediate Filament Proteins ,Tumor Cells, Cultured ,Animals ,Enhancer ,Gene ,Reporter gene ,Binding Sites ,Base Sequence ,POU domain ,Carcinoma ,Gene Expression Regulation, Developmental ,DNA ,General Medicine ,Molecular biology ,Embryonic stem cell ,Introns ,Neural stem cell ,Enhancer Elements, Genetic ,Mutation ,POU Domain Factors ,embryonic structures - Abstract
Nestin, an intermediate filament protein, is expressed in the neural stem cells of the developing central nervous system. This tissue-specific expression is driven by the neural stem cell-specific enhancer in the second intron of the nestin gene. In this study, we showed that the mouse nestin gene was expressed in pluripotent embryonic carcinoma (EC) P19 and F9 cells, not in the differentiated cell types. This cell type-specific expression was conferred by the enhancer in the second intron. Mutation of the conserved POU factor-binding site in the enhancer abolished the reporter gene expression in EC cells. Oct4, a Class V POU factor, was found to be coexpressed with nestin in EC cells. Electrophoretic mobility-shift assays and supershift assays showed that a unique protein-DNA complex was formed specifically with nuclear extracts of EC cells, and Oct4 protein was included. Together, these results suggest the functional relevance between the conserved POU factor-binding site and the expression of the nestin gene in pluripotent EC cells.
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- 2006
211. Surface Morphology Anisotropy and Stress Distribution Uniformity in Annealed Cu–W Films
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X.-H Li, Kun Xu, D.W. Fan, Yuan Wang, and Yongfeng Chen
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Materials science ,Annealing (metallurgy) ,Scanning electron microscope ,Mechanical Engineering ,Substrate (electronics) ,Sputter deposition ,Condensed Matter Physics ,Microstructure ,Mechanics of Materials ,Residual stress ,General Materials Science ,Composite material ,Thin film ,Anisotropy - Abstract
Copper-tungsten films were deposited on Si and Al2O3 substrates by magnetron sputtering and then in situ annealed in vacuum chamber at different temperatures. X-ray diffraction (XRD), scanning electron microscopy (SEM), and the polarization phase shift technique were used to characterize the microstructure, surface morphology, and residual stress of Cu–W films. The results indicated that there are two successive but distinctive stages of phase transition with the change of annealing temperatures. The evolution of surface morphology of Cu–W thin films shows a significant effect on the distribution of in-plane stresses. A strategy of integrating discrete wavelet transform and fractal geometry concepts was developed to analyze the anisotropy of surface structure of Cu–W thin films. The correlation between the anisotropy of surface morphology and the stress distribution of thin films was constructed. It is found that the stress distribution of the thin films is sensitive to the variations of the anisotropy of the surface structure with annealing temperature. The variation in the uniformity of in-plane stress distribution with the evolution of surface structure of thin films is independent of the choice of substrate materials.
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- 2005
212. Low-dose methotrexate combined with superficial X-ray in the treatment of folliculotropic mycosis fungoides: A case report
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Yanan Jiang, Ruzeng Xue, Weijia Wang, and Yongfeng Chen
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medicine.medical_specialty ,business.industry ,Treatment outcome ,Dermatology ,lcsh:RL1-803 ,Folliculotropic Mycosis Fungoides ,Low dose methotrexate ,030207 dermatology & venereal diseases ,03 medical and health sciences ,0302 clinical medicine ,Infectious Diseases ,030220 oncology & carcinogenesis ,lcsh:Dermatology ,Medicine ,business - Published
- 2017
213. Relationship between apparent diffusion coefficient and tumour cellularity in lung cancer
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Wenwei Wang, Xiao-Chu Yan, Lihua Chen, Yongfeng Chen, Jian Wang, Xiangdong Zhou, and Jiuquan Zhang
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Male ,Pathology ,medicine.medical_specialty ,Cytoplasm ,Lung Neoplasms ,lcsh:Medicine ,Adenocarcinoma ,Diagnostic Radiology ,Diffusion ,Diagnostic Medicine ,Biopsy ,medicine ,Medicine and Health Sciences ,Cancer Detection and Diagnosis ,Effective diffusion coefficient ,Humans ,Prospective Studies ,Prospective cohort study ,Lung cancer ,lcsh:Science ,Cell Nucleus ,Multidisciplinary ,medicine.diagnostic_test ,business.industry ,Radiology and Imaging ,lcsh:R ,Magnetic resonance imaging ,respiratory system ,Thorax ,medicine.disease ,Small Cell Lung Carcinoma ,body regions ,Diffusion Magnetic Resonance Imaging ,Oncology ,Carcinoma, Squamous Cell ,lcsh:Q ,Female ,business ,Software ,Diffusion MRI ,Research Article - Abstract
BACKGROUND AND OBJECTIVE: To prospectively investigate the relationship between the apparent diffusion coefficient (ADC) and cellularity in lung cancer. METHODS: Sixty patients histopathologically confirmed with lung cancer (41 men, 19 women) underwent diffusion-weighted magnetic resonance imaging of the chest (with b values of 50 and 1000 s/mm2). The median mean ADC (ADC mean) value and median minimum ADC (ADC min) value within each primary tumour were calculated and compared with the median nucleo-cytoplasmic ratio (NCR), which was selected to represent the cellularity. The correlation between the NCR and ADC mean/ADC min was calculated with SPSS 18.0 software. RESULTS: The mean ADC mean values, ADC min values and median NCR were (1.07 ± 0.12) × 10(-3) mm2/s, (0.86 ± 0.14) × 10(-3) mm2/s, and (14.9 ± 2.6) %, respectively, in adenocarcinoma; (0.88 ± 0.10) × 10(-3) mm2/s, (0.73 ± 0.12) × 10(-3)) mm2/s, and (20.6 ± 4.4) %, respectively, in squamous cell carcinoma; and (0.89 ± 0.13) × 10(-3) mm2/s, (0.67 ± 0.13) × 10(-3) mm2/s, and (18.3 ± 3.5) %, respectively in small cell lung cancer. The NCR of squamous cell carcinoma and small cell lung cancer is greater than that of adenocarcinoma (P < 0.01 and P = 0.002, respectively). There was an inverse relationship between ADC mean/NCR and ADC min/NCR (r = -0.60, P = 0.001 and r = -0.47, P < 0.001, respectively). CONCLUSION: There is a significant inverse relationship between tumour cellularity and ADC in lung cancer. However, tumour cellularity most likely is not the sole determinant of the ADC.
- Published
- 2014
214. Protective Effect of Shenlingbaizhu Powder on Peroxidation Injury and Inflammatory Response in Mice with Pneumonia.
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Jinli FENG, Cheng ZHANG, Houjun CHEN, Ziliang CHEN, Yongfeng CHEN, and Zhiguang WU
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INFLAMMATION ,PNEUMONIA ,MICE ,PEROXIDATION ,WOUNDS & injuries ,PNEUMOCOCCAL vaccines - Abstract
Objectives] The study aims to explore the protective effect of Shenlingbaizhu powder on peroxidation injury and inflammatory response in mice with pneumonia. [Methods] 60 NIH mice were randomly divided into the blank group, model group, control group, large dose group, medium dose group and small dose group of Shenlingbaizhu powder. The mice in the control group were given cefixime granules, while the mice in each group of Shenlingbaizhu powder were given corresponding concentrations of Shenlingbaizhu powder water decoction by gavage. After 7 d, the content of MAD, SOD and CRP in the mice were detected by ELISA, while the content of NO was detected by fluorescence, and lung index was also detected. [Results] The medium dose and large dose of Shenlingbaizhu powder can effectively reduce the concentration of MAD and improve the level of SOD in mice with pneumonia. The effect of the large dose of Shenlingbaizhu powder is more obvious than that of the control group. Moreover, the large dose of Shenlingbaizhu powder can effectively reduce the level of NO in mice with pneumonia. In addition, the medium dose and large dose of Shenlingbaizhu powder can reduce the lung index and CRP level of mice with pneumonia, and the results are statistically significant. [Conclusions] The medium dose and large dose of Shenlingbaizhu powder can effectively reduce the concentration of MAD and improve the level of SOD in mice with pneumonia. The effect of the large dose of Shenlingbaizhu powder is more obvious than that of the control group. Moreover, the large dose of Shenlingbaizhu powder can effectively reduce the level of NO in mice with pneumonia. In addition, the medium dose and large dose of Shenlingbaizhu powder can reduce the lung index and CRP level of mice with pneumonia, and the results are statistically significant. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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215. Analysis on the Clinical Effect of Shenling Baizhu San Combined with Routine Treatment on Bacterial Pneumonia in Children.
- Author
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Jinli FENG, Cheng ZHANG, Houjun CHEN, Ziliang CHEN, Yongfeng CHEN, and Zhiguang WU
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INFLAMMATION ,TREATMENT effectiveness ,PNEUMONIA ,GASTROINTESTINAL system ,SYMPTOMS - Abstract
[Objectives] To explore the effect of Shenling Baizhu San combined with routine treatment on the clinical efficacy, gastrointestinal function protection, inflammatory response and immune function of children with bacterial pneumonia. [Methods] From July 2017 to January 2018, 80 children with bacterial pneumonia were randomly selected and divided into observation group and control group with 40 cases in each group. The control group was treated with conventional Western medicine, while the observation group was treated with Shenling Baizhu San on the basis of conventional treatment, with a period of 10 d. Then, we compared the clinical efficacy, incidence of gastrointestinal symptoms, WBC, CRP, CD4+ and CD8+ levels between the two groups. [Results] The clinical efficacy of the observation group was better than that of the control group(P<0.05). After treatment, the levels of WBC and CRP in the two groups decreased, especially in the observation group(P<0.05). After treatment, the level of CD4+ in both groups increased significantly, while the level of CD8+ decreased significantly, and the level of CD4+ in the observation group was significantly higher than that in the control group after treatment. The incidence of gastrointestinal symptoms in the observation group was significantly lower than that in the control group(P<0.01). [Conclusions] Shenling Baizhu San can obviously improve the clinical effect of bacterial pneumonia in children and has the protective effect of gastrointestinal tract, and its mechanism may be related to its anti-inflammatory and immunomodulatory effects. [ABSTRACT FROM AUTHOR]
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- 2020
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216. Investigation of the numerical simulation of debris flow fluid with concern of phase transition
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Binbin Zhao, Yongfeng Cheng, Yi Liu, Xiaoang Kong, Zhi Yang, Ruiming Tong, Xiyu Xu, and Yuanjing Deng
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debris flow ,fluid ,phase transition ,numerical simulation ,yield stress ,Science - Abstract
From a variety of yield stress fluid models, an elastoviscoplastic Herschel-Bulkley (EVPHB) model written in 3D is selected and coupled with a Finite Element Method with Lagrangian Integration Points (FEMLIP) to solve boundary value problems with large deformation process. By tracing the historical variables of a material point, it is verified that in a time-independent flow the elastic strain and viscous strain rate could be accurately reproduced by EVPHB model. For a time-dependent flow, because of the addition of elasticity, the EVPHB model makes the material experience a deformation process which is significantly distinctive from that produced by a pure regularized Herschel-Bulkley model. Benchmarks also show that in FEMLIP the yielded and unyielded zones could be easily defined by EVPHB model according to the stress of a material point. Lastly, it is shown that EVPHB model also induces a stress relaxation process for materials under constant strain. The suitability of FEMLIP to model elastoviscoplastic fluid is verified.
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- 2022
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217. Cutaneous plasmacytosis occurring on the head-face area: a Chinese case
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Yongfeng, Chen, Ruzeng, Xue, Lining, Huang, Wenjing, Chen, Tieqiang, Wu, and Huiqing, Pan
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Male ,Asian People ,Biopsy ,Plasma Cells ,Humans ,Middle Aged ,Skin Diseases ,Facial Dermatoses - Published
- 2013
218. Influence of Coriolis Force on the Flow Field of Combined Top and Bottom Blown Converter
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Jingshe Li, Yongfeng Chen, Tongbo Zhang, and Haiyan Tang
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Physics ,Deflection (engineering) ,Water model ,Mechanical engineering ,Mechanics ,Clockwise ,Flow field ,Deflection angle ,Tuyere - Abstract
Based on the principle of Coriolis force and the structure of combined top and bottom blown converter, the relationship between Coriolis force and the converter was analyzed theoretically. It is concluded that Coriolis force affects converter’s flow field by the action on top and bottom blown gas. It makes top gas clockwise deflection and bottom gas counterclockwise deflection, and the deflection angle of the former smaller than the latter. According to the theoretical analysis, the water model experiments were designed to primarily test and verify the influence of Coriolis force on converter’s flow field. It is shown from the investigation that the counterclockwise trend of bottom gas caused by Coriolis force can be superimposed with the counterclockwise trend of flow field caused by the arrangement of bottom tuyeres, further to reduce the mixing time of bath.
- Published
- 2013
219. Simultaneous ABO-incompatible living-donor liver transplantation and splenectomy without plasma exchange in China: Two case reports.
- Author
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Guoyong Chen, Janjun Sun, Sidong Wei, Yongfeng Chen, Gaofeng Tang, Zhantao Xie, Huaen Xu, Janbin Chen, Huibo Zhao, Zhenhua Yuan, Weiwei Wang, Guangbo Liu, Bing Wang, and Biao Niu
- Published
- 2017
- Full Text
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220. Experimental Study on the Production of Nitrogen-Bearing Stainless Steel by Injecting Nitrogen Gas
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Jingshe Li, Li-yuan Sun, Yongfeng Chen, Shufeng Yang, Lifeng Zhang, and Anping Dong
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Bearing (mechanical) ,Materials science ,chemistry ,law ,Metallurgy ,Nitrogen gas ,chemistry.chemical_element ,Nitrogen ,law.invention - Published
- 2012
221. Fluid Flow and Inclusion Entrapment in the Runner Steel During Ingot Casting
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Lifeng Zhang, Yongfeng Chen, and Shufeng Yang
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Entrapment ,Materials science ,Metallurgy ,Fluid dynamics ,Inclusion (mineral) ,Tundish ,Ingot casting - Published
- 2012
222. Inclusion Characteristics in Stainless Steel Ingots
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Shufeng Yang, Yongfeng Chen, Jun Ge, George Shannon, Greg Dowling, and Lifeng Zhang
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Materials science ,Metallurgy ,Ingot ,Inclusion (mineral) - Published
- 2012
223. WITHDRAWN: BMP signaling and neurogenesis of developing spinal cord
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François Guillemot, Lin Li, Zhihui Xie, Naihe Jing, Ye-Guang Chen, Zhenfei Li, and Yongfeng Chen
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medicine.anatomical_structure ,Developmental Neuroscience ,business.industry ,Bmp signaling ,Neurogenesis ,Medicine ,business ,Spinal cord ,Neuroscience ,Developmental Biology - Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
- Published
- 2012
224. [Early effectiveness of combining radial forearm free flap and adjacent tissue flap in reconstruction of palatomaxillary defects]
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Yongfeng, Chen, Kai, Zhang, Jiancheng, Li, Jingcheng, Xu, Shengkai, Liao, and Tao, Xu
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Male ,Maxillary Neoplasms ,Palate ,Transplants ,Skin Transplantation ,Middle Aged ,Plastic Surgery Procedures ,Surgical Flaps ,Forearm ,Treatment Outcome ,Maxilla ,Humans ,Female ,Aged - Abstract
To investigate the method of combining radial forearm free flap and adjacent tissue flap in reconstruction of palatomaxillary defects and its effectiveness.Between March 2005 and May 2010, 17 patients with palatomaxillary defects were treated. There were 11 males and 6 females with an age range of 45-74 years (mean, 62.5 years), including 1 case of benign tumor and 16 cases of malignant tumors (7 cases of squamous cell carcinoma of palate, 1 case of recurring squamous cell carcinoma of palate, 1 case of malignant melanoma of palate, 1 case of adenoid cystic carcinoma of palate, 1 case of malignant melanoma of maxilla, 1 case of ductal carcinoma of maxilla, and 4 cases of squamous cell carcinoma of maxilla). The maxillectomy defect ranged from 7.0 cm x 5.5 cm to 10.0 cm x 7.5 cm. According to Brown's classification for the maxillectomy defect, there were type II in 15 cases, type III in 2 cases. Palatomaxillary defects were repaired with radial forearm free flap and buccal fat pad in 11 cases, and with radial forearm free flap, buccal fat pad, and mandibular osteomuscular flap pedicled with temporal muscle in 6 cases. The effectiveness was evaluated after operation by observing the vitality of the flap, the functions of speech, swallowing, breath, and the facial appearance.All cases were followed up 6-12 months without tumor recurrence. All flaps and skin grafts at donor sites survived. The functions of speech, swallowing, and breath were normal without obvious opening limitation. The facial appearance was satisfactory without obvious maxillofacial deformity. No enophthalmos occurred in patients with orbital floor and infraorbital rim defects. The patients had no oronasal fistula with satisfactory oral and nasal functions.According to the type of palatomaxillary defects, it can have good early effectiveness to select combining radial forearm free flap and buccal fat pad or combining radial forearm free flap, buccal fat pad, and mandibular osteomuscular flap for repairing defects.
- Published
- 2011
225. The Tension-Shear and Compression-Shear Joint Strength Model for Unsaturated Clay and Its Application to Slopes
- Author
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Xiaoang Kong, Yongfeng Cheng, Binbin Zhao, Yi Liu, and Jingshan Han
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unsaturated soil ,adsorption effect ,tension-shear ,compression-shear ,joint strength ,Science - Abstract
The capillary component and adsorptive component of matric suction differently impact the soil strength. Due to the cavitation effects of pore water, the adsorption effect dominates the behavior of soil when matric suction exceeds the cavitation tension. Based on the binary medium theory, a compression-shear strength model for unsaturated soils considering both capillary effect and adsorption effect is established. Compared with test data, the proposed compression-shear strength model has better prediction performance on the compression-shear strength of soil over a range of wide suction. The soil failure depends both on tension-shear stress and compression-shear stress. The tension-shear coupling mechanism in the soil is first investigated. A concept of closed stress point is introduced to divide the two zones of tension-shear coupling stress and compression-shear stress. According to the compression-shear strength model and tension-shear failure mechanism, the tension-shear and compression-shear joint strength model applicable to plane stress conditions is then established. Compared with test data, the proposed model in this article can better predict the nonlinear strength characteristics of clays and has better applicability. Finally, using the user material subroutine (UMAT), the secondary development of the joint strength model is conducted in ABAQUS and then applied to the slope stability analysis. The calculation results show that the established strength model presents a reasonable description of the development of the tension-shear coupling plastic zone in slope and gives an accurate safety factor.
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- 2022
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226. Study on Trusted Vitual Machine Platform Based on Cipher Card
- Author
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Ningxia, Yang, primary, Yongfeng, Chen, additional, and Min, Qin, additional
- Published
- 2015
- Full Text
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227. First intron of nestin gene regulates its expression during C2C12 myoblast differentiation
- Author
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Naihe Jing, Wei Bian, Ting Zhang, Yongfeng Chen, Xing Cui, Zhigang Jin, and Hua Zhong
- Subjects
Biophysics ,Nerve Tissue Proteins ,macromolecular substances ,Biology ,MyoD ,Biochemistry ,Cell Line ,Myoblasts ,Nestin ,Mice ,MyoD Protein ,Intermediate Filament Proteins ,Myocyte ,Animals ,Progenitor cell ,Enhancer ,Promoter Regions, Genetic ,Gene Expression Regulation, Developmental ,Cell Differentiation ,General Medicine ,Molecular biology ,Neural stem cell ,Introns ,nervous system ,embryonic structures ,C2C12 - Abstract
Nestin is an intermediate filament protein expressed in neural progenitor cells and in developing skeletal muscle. Nestin has been widely used as a neural progenitor cell marker. It is well established that the specific expression of the nestin gene in neural progenitor cells is conferred by the neural-specific enhancer located in the second intron of the nestin gene. However, the transcriptional mechanism of nestin expression in developing muscle is still unclear. In this study, we identified a muscle cell-specific enhancer in the first intron of mouse nestin gene in mouse myoblast C2C12 cells. We localized the core enhancer activity to the 291-661 region of the first intron, and showed that the two E-boxes in the core enhancer region were important for enhancer activity in differentiating C2C12 cells. We also showed that MyoD protein was involved in the regulation of nestin expression in the myogenic differentiation of C2C12 cells.
- Published
- 2008
228. Design and Evaluation of Paeonol-Loaded Liposomes in Thermoreversible Gels for Atopic Dermatitis
- Author
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Yu Wang, Yan Yue, Ruoyang Jia, Xinyi Liu, Zhiqing Cheng, Yongfeng Cheng, Yinxiang Xu, Zili Xie, and Hongmei Xia
- Subjects
paeonol ,thermosensitive gel ,liposome–hydrogel ,antioxidant ,atopic dermatitis ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Paeonol (PAE) is a hydrophobic drug. In this study, we encapsulated paeonol in a lipid bilayer of liposomes (PAE-L), which delayed drug release and increased drug solubility. When PAE-L was dispersed in gels (PAE-L-G) based on a poloxamer matrix material for local transdermal delivery, we observed amphiphilicity, reversible thermal responsiveness, and micellar self-assembly behavior. These gels can be used for atopic dermatitis (AD), an inflammatory skin disease, to change the surface temperature of the skin. In this study, we prepared PAE-L-G at an appropriate temperature for the treatment of AD. We then assessed the gel’s relevant physicochemical properties, in vitro cumulative drug release, and antioxidant properties. We found that PAE-loaded liposomes could be designed to increase the drug effect of thermoreversible gels. At 32 °C, PAE-L-G could change from solution state to gelatinous state at 31.70 ± 0.42 s, while the viscosity was 136.98 ± 0.78 MPa.S and the free radical scavenging rates on DPPH and H2O2 were 92.24 ± 5.57% and 92.12 ± 2.71%, respectively. Drug release across the extracorporeal dialysis membrane reached 41.76 ± 3.78%. In AD-like mice, PAE-L-G could also relieve skin damage by the 12th day. In summary, PAE-L-G could play an antioxidant role and relieve inflammation caused by oxidative stress in AD.
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- 2023
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- View/download PDF
229. Effects of weiganli on the hemopoietic function of the myelosuppressed anemic mice
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Yongfeng, Chen, Bide, Zhu, Suchun, Yan, Li, Zhang, and Jing, Li
- Subjects
Male ,Mice, Inbred BALB C ,Anemia, Myelophthisic ,Hematopoietic Stem Cells ,Hematopoiesis ,Colony-Forming Units Assay ,Disease Models, Animal ,Mice ,Random Allocation ,Granulocyte-Macrophage Progenitor Cells ,Animals ,Humans ,Drugs, Chinese Herbal ,Megakaryocyte-Erythroid Progenitor Cells - Abstract
To study the effect of weiganli ([Chinese characters: see text]) on bone marrow hemopoiesis.The effects of weiganli on the peripheral blood picture and the number of bone marrow nucleated cells (BMCs) were observed in myelosuppressed anemic model mice, and the effects of weiganli on the growth of colony forming unit-granulocyte macrophage (CFU-GM), colony forming unit-erythroid (CFU-E), burst forming unit-erythroid (BFU-E), colony forming unit-megkaryocyte (CFU-Meg) were investigated by in vitro cell culture technique. The hemopoietic stem cells (HSCs, c-kit+) in bone marrow were double stained with fluorescent antibody PE-C-Kit and FITC-CD45, and the HSCs (c-kit+) were counted by flow cytometer with CD45/SSC (side scatter) gating.Peripheral blood cell counts and the number of BMCs were significantly improved after weiganli administration; and bone marrow hemopoietic stem/progenitor cells were significantly increased.Weiganli can effectively promote the recovery of hemopoietic function in the myelosuppressed anemic mice.
- Published
- 2007
230. Percutaneous Electroosmosis of Berberine-Loaded Ca2+ Crosslinked Gelatin/Alginate Mixed Hydrogel
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Yinyin Liu, Si Shen, Yifang Wu, Mengmeng Wang, Yongfeng Cheng, Hongmei Xia, Ruoyang Jia, Chang Liu, Yu Wang, Ying Xia, Xiaoman Cheng, Yan Yue, and Zili Xie
- Subjects
gelatin/alginate hydrogel ,berberine hydrochloride ,electroosmotic transdermal ,Organic chemistry ,QD241-441 - Abstract
Flexible conductive hydrogel has been driven by scientific breakthroughs and offers a wide variety of applications, including sensors, electronic skins, biomedicine, energy storage, etc. Based on the mixed-ion crosslinking method, gelatin and sodium alginate (Gel–Alg) composite hydrogels were successfully prepared using Ca2+ crosslinking. The migration behavior of berberine hydrochloride (BBH) in the matrix network structure of Gel–Alg hydrogel with a certain pore size under an electric field was studied, and the transdermal effect of berberine hydrochloride under an electric field was also studied. The experimental results show that Gel–Alg has good flexibility and conductivity, and electrical stimulation can enhance the transdermal effect of drugs. Gel–Alg composite hydrogel may be a new material with potential application value in future biomedical directions.
- Published
- 2022
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231. Ligustrazine as an Extract from Medicinal and Edible Plant Chuanxiong Encapsulated in Liposome–Hydrogel Exerting Antioxidant Effect on Preventing Skin Photoaging
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Chang Liu, Ying Xia, Yufan Li, Yongfeng Cheng, Hongmei Xia, Yu Wang, Yan Yue, Yifang Wu, Xiaoman Cheng, Yinxiang Xu, and Zili Xie
- Subjects
ligustrazine hydrochloride ,liposome–hydrogel ,in vitro and ex vivo release ,antioxidant ,Organic chemistry ,QD241-441 - Abstract
Long-term sunlight exposure will cause the accumulation of free radicals in the skin and lead to oxidative damage and aging, antioxidant drugs have gradually become the focus of research, but there is little research on antioxidant drugs for percutaneous treatment. The purpose of this study was to prepare ligustrazine hydrochloride (TMPZ)-loaded liposome–hydrogel (TMPZ-LG), evaluate its antioxidant properties, and apply it on the skin of mice to observe whether it had preventive and therapeutic effect on the irradiation under the ultraviolet rays, in an attempt to make it into a new kind of delivery through the skin. TMPZ-LG was prepared by the combination of film dispersion and sodium carboxymethylcellulose (2%, CMC-Na) natural swelling method. The release rates in vitro permeation across the dialysis membrane and ex vivo transdermal had both reached 40%; the scavenging effect of TMPZ-LG on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and H2O2 were 65.57 ± 4.13% and 73.06 ± 5.65%; the inhibition rate of TMPZ-LG on malondialdehyde (MDA) production in liver homogenate and anti-low density lipoprotein (LDL) oxidation experiments ex vivo were 15.03 ± 0.9% and 21.57 ± 1.2%. Compared with untreated mice, the skin pathological symptoms of mice coated with TMPZ-LG were significantly reduced after ultraviolet irradiation, and there was statistical significance. The results showed TMPZ-LG could exert good antioxidant activity in vitro and ex vivo; therefore, it is feasible to prevent and treat skin oxidation.
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- 2022
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232. Full-Scale Testing on Seismic Performance of Surge Arrester with Retrofitted Composite Insulators
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Sheng Li, Yongfeng Cheng, Zhicheng Lu, Nelson Lam, Yaodong Xue, and Haibo Wang
- Subjects
GFRP insulators ,seismic performance ,bending ,joints/joining ,shaking table test ,Building construction ,TH1-9745 - Abstract
In electrical substations, glass-fibre reinforced polymer (GFRP) insulators provide an alternative to porcelain insulators for better seismic performance. The bonded connection between the composite tube and the metal end fitting is a weak link under earthquake actions, and the failure risk of ultra-high voltage (UHV) substation equipment with GFRP composite insulators can be considerable in places with high seismicity. This study solved the problem by retrofitting and experimentally qualifying the seismic performance of surge arresters made of composite insulators. To ensure safety under a bending moment corresponding to the seismic demand, the bonded sleeve joint between the tube and end fitting was retrofitted by shear stiffeners and higher strength end fitting. A full-scale shaking table test was carried out to verify the performance of the retrofitted surge arrester, and the seismic responses to increasing earthquake actions were analyzed. The specimens in this study were full-scale, had the largest dimensions among substation equipment of the same type, and were subjected to an extremely high earthquake action of 0.5 g; therefore, the seismic testing results produced in this study can serve as an important reference for the industry.
- Published
- 2022
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- View/download PDF
233. A Case of Cutaneous Blastic Plasmacytoid Dendritic Cell Neoplasm
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Ruzeng Xue, Youshou Gu, Bin Yang, Tieqiang Wu, Jushi Qiu, Yongfeng Chen, and Huiqing Pan
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Pathology ,medicine.medical_specialty ,business.industry ,Medicine ,Dermatology ,General Medicine ,Blastic plasmacytoid dendritic cell neoplasm ,Dendritic cell ,business - Published
- 2010
234. The Fabrication of Docetaxel-Containing Emulsion for Drug Release Kinetics and Lipid Peroxidation
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Yifang Wu, Mengmeng Wang, Yufan Li, Hongmei Xia, Yongfeng Cheng, Chang Liu, Ying Xia, Yu Wang, Yan Yue, Xiaoman Cheng, and Zili Xie
- Subjects
docetaxel ,emulsion ,drug release ,lipid peroxidation ,Pharmacy and materia medica ,RS1-441 - Abstract
Docetaxel (DTX)-based formulation development is still confronted with significant challenges, due to its refractory solubility and side effects on normal tissues. Inspired by the application of the transdermal drug delivery model to topical treatment, we developed a biocompatible and slow-release DTX-containing emulsion via self-assembly prepared by a high-speed electric stirring method and optimized the formulation. The results of accelerated the emulsion stability experiment showed that the emulsion prepared at 10,000 rpm/min had a stability of 89.15 ± 2.05%. The ADME, skin irritation, skin toxicity and molecular interaction between DTX and excipients were predicted via Discovery Studio 2016 software. In addition, DTX addition in oil or water phases of the emulsion showed different release rates in vitro and ex vivo. The DTX release ex vivo of the DTX/O-containing emulsion and the DTX/W-containing emulsion were 45.07 ± 5.41% and 96.48 ± 4.54%, respectively. In vitro antioxidant assays and anti-lipid peroxidation models revealed the antioxidant potential of DTX. However, DTX-containing emulsions could maintain and even enhance the antioxidant effect, both scavenging free radicals in vitro and inhibiting the process of lipid peroxidation.
- Published
- 2022
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- View/download PDF
235. In Vitro Evaluation of Kaempferol-Loaded Hydrogel as pH-Sensitive Drug Delivery Systems
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Qin Zhang, Xinying Yang, Yifang Wu, Chang Liu, Hongmei Xia, Xiaoman Cheng, Yongfeng Cheng, Ying Xia, and Yu Wang
- Subjects
kaempferol ,carbopol 934 ,antioxidation ,different pH ,drug release ,Organic chemistry ,QD241-441 - Abstract
The purpose of this study was to prepare and evaluate kaempferol-loaded carbopol polymer (acrylic acid) hydrogel, investigate its antioxidant activity in vitro, and compare the effects on drug release under different pH conditions. Drug release studies were conducted in three different pH media (pH 3.4, 5.4, and 7.4). The kaempferol-loaded hydrogel was prepared by using carbopol 934 as the hydrogel matrix. The morphology and viscosity of the preparation were tested to understand the fluidity of the hydrogel. The antioxidant activity of the preparation was studied by scavenging hydrogen peroxide and 2,2-diphenyl-1-picrilhidrazil (DPPH) radicals in vitro and inhibiting the production of malondialdehyde in mouse tissues. The results showed that kaempferol and its preparations had high antioxidant activity. In vitro release studies showed that the drug release at pH 3.4, 5.4, and 7.4 was 27.32 ± 3.49%, 70.89 ± 8.91%, and 87.9 ± 10.13%, respectively. Kaempferol-loaded carbopol hydrogel displayed greater swelling and drug release at higher pH values (pH 7.4).
- Published
- 2022
- Full Text
- View/download PDF
236. miR-30a can inhibit DNA replication by targeting RPA1 thus slowing cancer cell proliferation.
- Author
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Zhenyou Zou, Mengjie Ni, Jing Zhang, Yongfeng Chen, Hongyu Ma, Shihan Qian, Longhua Tang, Jiamei Tang, Hailun Yao, Chengbin Zhao, Xiongwen Lu, Hongyang Sun, Jue Qian, Xiaoting Mao, Xulin Lu, Qun Liu, Juping Zen, Hanbing Wu, Zhaosheng Bao, and Shudan Lin
- Subjects
CELL proliferation ,DNA replication ,CANCER cell growth ,OVARIAN cancer diagnosis ,KINASE inhibitors ,TRANSFORMING growth factors - Abstract
Cell proliferation was inhibited following forced over-expression of miR-30a in the ovary cancer cell line A2780DX5 and the gastric cancer cell line SGC7901R. Interestingly, miR-30a targets the DNA replication protein RPA1, hinders the replication of DNA and induces DNA fragmentation. Furthermore, ataxia telangiectasia mutated (ATM) and checkpoint kinase 2 (CHK2) were phosphorylated after DNA damage, which induced p53 expression, thus triggering the S-phase checkpoint, arresting cell cycle progression and ultimately initiating cancer cell apoptosis. Therefore, forced miR-30a over-expression in cancer cells can be a potential way to inhibit tumour development. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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237. Retraction
- Author
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Yongfeng Chen, Qing Zhang, Marcia Petrini, Yan-Qiong Ouyang, and You-xian Xu
- Subjects
medicine.medical_specialty ,Nursing ,business.industry ,Family medicine ,Obstetrics and Gynecology ,Medicine ,Breastfeeding knowledge ,business - Abstract
Ouyang,Y, Xu Y, Petrini M, Zhang Q, Chen Y. (2011). Breastfeeding knowledge, attitudes, and behavior of female Chinese physicians in 2009. J Hum Lact. (Original DOI: 10.1177/0890334411411916)
- Published
- 2011
238. Study on Seismic Performance of Porcelain Pillar Electrical Equipment Based on Nonlinear Dynamic Theory
- Author
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Yaodong Xue, Yongfeng Cheng, Zhubing Zhu, Sheng Li, Zhenlin Liu, Hulun Guo, and Shujun Zhang
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In order to consider the influence of nonlinear characteristics of porcelain pillar electrical equipment on the dynamic response under seismic excitation, a theoretical analysis method of nonlinear dynamics was raised to define the nonlinear parameter of the flange connection and establish a dynamic model of porcelain pillar electrical equipment. The theoretical analysis and the test results have a good degree of fitting, which verifies the correctness of the dynamic model and reveals the nonlinear seismic response law of the porcelain pillar equipment. According to the results, both the nonlinear calculation results of the displacement at the top end of the porcelain pillar and the stress at the bottom end of the porcelain pillar are smaller than the results in the linear calculation. The difference between them increases gradually with the increase of seismic excitation. The differences in displacement and stress at a seismic excitation of 0.5 g are 14.58% and 23.25%, respectively. When the nonlinear parameter increases to a certain value, the impact of maximum stress on the bottom of the porcelain pillar is very small and the change is not obvious. The research provides a theoretical reference for the seismic design of pillar electrical equipment.
- Published
- 2021
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- View/download PDF
239. Evaluation method on seismic risk of substation in strong earthquake area.
- Author
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Jiawei Cui, Ailan Che, Sheng Li, and Yongfeng Cheng
- Subjects
Medicine ,Science - Abstract
Frequent earthquakes in strong earthquake areas pose a great threat to the safety operation of electric power facilities. There exists a pressing research need to develop an assessment method for the seismic risk of substations, i.e., the hubs of power system networks. In this study, based on Incremental Dynamic Analysis (IDA), Probabilistic Seismic Demand Model (PSDM) and reliability theory, a vulnerability model for a substation is obtained, based on considering the relationships between Peak Ground Acceleration (PGA) and four seismic damage states (complete, extensive, moderate, and slight.) via a probabilistic approach. After an earthquake, the scope of influence and PGA distribution are evaluated using information recorded by the seismic observation stations, based on using interpolation or an empirical formula for the PGA attenuation. Therefore, the seismic risk can be evaluated by combining ground motion evaluation and the pre-built vulnerability model. The Wuqia- Kashgar area of Xinjiang was selected as the study area; it is an Earthquake-prone area, and one of the starting points for new energy transmission projects in China. Under a hypothetical earthquake (MS 7.9), the seismic risk of the substations was evaluated. The results show that: this method is able to give the probabilities of the four damage states of the substations, four substations close to the epicenter only have a probability of slight damage (45%-88%) and other substations are safer.
- Published
- 2021
- Full Text
- View/download PDF
240. Uplift Bearing Capacity of Transmission Tower Foundation in Reinforced Aeolian Sand Using Simplified Model Tests
- Author
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Shijun Ding, Yongfeng Cheng, Hong Zheng, Feng Xue, Zhibao Nie, and Yin Man
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In order to analyze the uplift bearing capacity of transmission tower foundation in the geosythetic-reinforced aeolian sand, a series of simplified indoor modeling tests are carried out. A simplified reduced-scale foundation made according to the prototype and the uplift bearing capacity of transmission tower foundation in geosynthetic-reinforced aeolian sand is studied. Three kinds of reinforcement materials are embedded in the sand according to five ways of layout spacing. A total of 15 reinforcement schemes are tested. The results show that ultimate uplift bearing capacity of transmission tower foundation can be significantly improved by the reinforcement treatment of geotechnical materials in the aeolian sand. The type and spacing of reinforced materials also have a significant influence on the uplift bearing capacity of the foundation model in reinforced aeolian sand, and the effect of reinforcement works until the end of the loading process. The comprehensive effect is evaluated by the ratio of bearing capacity improvement and the total layer of reinforced materials. Based on the above results, the bearing mechanism of transmission tower foundation in geosynthetic-reinforced aeolian sand is elaborated and analyzed in detail.
- Published
- 2021
- Full Text
- View/download PDF
241. An XML Approach to Semantically Extract Data from HTML Tables.
- Author
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Andersen, Kim Viborg, Debenham, John, Wagner, Roland, Jixue Liu, Zhuoyun Ao, Ho-Hyun Park, and Yongfeng Chen
- Abstract
Data intensive information is often published on the internet in the format of HTML tables. Extracting some of the information that is of users' interest from the internet, especially when large number of web pages need to be accessed, is time consuming. To automate the processes of information extraction, this paper proposes an XML way of semantically analyzing HTML tables for the data od interest. It firstly introduces a mini language in XML syntax for specifying ontologies that represent the data of interest. Then it defines algorithms that parse HTML tables to a specially defined type of XML trees. The XML trees are then compared with the ontologies to semantically analyze and locate the part of table or nested tables that have the interesting data. Finally, interesting data, once identified, is output as XML documents. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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- View/download PDF
242. Research on Bending Rigidity at Flange Connections of UHV Composite Electrical Equipment
- Author
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Haibo Wang, Yongfeng Cheng, Zhicheng Lu, Zhubing Zhu, and Shujun Zhang
- Subjects
Physics ,QC1-999 - Abstract
Pillar electrical equipment is an important part of substations. The application of composite materials in pillar equipment can facilitate the improvement of the seismic performance of electrical equipment. In this paper, the test of elastic modulus and bending rigidity was conducted for individual composite elements in insulators and arresters, and the calculation formula for bending rigidity at the composite flange cementing connections was put forward. The numerical simulation model for the earthquake simulation shaking table test of ±1,100 kV composite pillar insulators was established, in which the bending rigidity value for the flange cementing part was obtained by the test or calculation formula. The numerical simulation results were compared with the earthquake simulation shaking table test results, the dynamic characteristics and seismic response of the model were compared, respectively, the validity of the proposed calculation formula for flange bending rigidity of composite cementing parts was verified, and a convenient and effective means was provided for calculating the seismic performance of composite electrical equipment.
- Published
- 2020
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- View/download PDF
243. Wavelet Packet Method for Locating Critical Slip Surface Using the Strength Reduction Method
- Author
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Yongfeng Cheng, Zhibao Nie, Chao Han, Shijun Ding, and Kaiyuan Liu
- Subjects
slope stability analysis ,strength reduction method ,critical slip surface ,wavelet packet analysis ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
When the finite element-strength reduction method is used for two-dimensional slope stability analysis for elastic-perfectly plastic material, the failure criterion usually adopts the criterion of plastic zone penetration. That is, when the slope is in the limit equilibrium state, the plastic zone goes through the slope from the toe to the top. Meanwhile, the critical slip surface is composed of a series of points of maximum equivalent plastic strain along the depth direction. By deploying a set of parallel lines approximately perpendicular to the slope surface and picking out the points of these lines with the maximum equivalent strain points, we obtain a series of points taking on a wave shape, which constitutes a signal function. Subsequently, the wavelet packet analysis is used to smooth these points, i.e., locating the critical slip surface. The analysis of classic examples and comparison with Spencer’s method show that the proposed method in this paper is reasonable and effective.
- Published
- 2021
- Full Text
- View/download PDF
244. Smad6 promotes neuronal differentiation in the intermediate zone of the dorsal neural tube by inhibition of the Wnt/β-catenin pathway.
- Author
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Zhihui Xie, Yongfeng Chen, Zhenfei Li2, Ge Bai, Yue Zhu, Rui Yan, Fangzhi Tan, Ye-Guang Chen, Guillemot, Francois, Lin Li, and Naihe Jing
- Subjects
- *
WNT genes , *CELL proliferation , *BONE morphogenetic proteins , *CELL cycle , *INTERLEUKIN-2 - Abstract
Proliferation of the neural/neuronal progenitor cells (NPCs) at the ventricular zone of the dorsal spinal cord requires the stimuli of Wnt and bone morphogenic protein (BMP). However, how these two signaling pathways are regulated to initiate differentiation in the NPCs as they enter the intermediate zone is not known. Here, we show that Smad6, a negative regulator of BMP signaling, is expressed in the intermediate zone of the chick dorsal spinal cord. Knockdown experiments show that Smad6 is required for promoting NPCs to exit the cell cycle and differentiate into neurons. Although we find that Smad6 inhibits BMP signaling, as expected, we also find that Smad6 unexpectedly inhibits the Wnt/β-catenin pathway. The inhibition of the Wnt/β-catenin pathway by Smad6 is independent of its effect on the BMP pathway. Rather, Smad6 through its N-terminal domain and link region enhances the interaction of C-terminal binding protein with the β-catenin/T cell factor (TCF) complex and the TCF-binding element to inhibit β-catenin-mediated transcriptional activation. Our study provides evidence that transition of NPCs from a proliferative state to a differentiating state is controlled by the dual inhibitory role of Smad6 to both BMP and Wnt signaling at the level of transcription. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
245. Hydrogen Peroxide Promotes Aβ Production through iNK-dependent Activation of γ-Secretase.
- Author
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Chengyong Shen, Yongfeng Chen, Huaqing Liu, Kejing Zhang, Ting Zhang, Anning Lin, and Naihe Jing
- Subjects
- *
HYDROGEN peroxide , *AMYLOID , *GENE silencing , *GENETIC regulation , *NEUROBLASTOMA , *NERVOUS system tumors , *ALZHEIMER'S disease , *GENE therapy - Abstract
Accumulation of senile plaques composed of amyloid β-peptide (Aβ) is a pathological hallmark of Alzheimer disease (AD), and Aβ is generated through the sequential cleavage of amyloid precursor protein (APP) by β- and γ-secretase. Although oxidative stress has been implicated in the AD pathogenesis by inducing Aβ production, the underlying mechanism remains elusive. Here we show that the pro-oxidant H2O2 promotes Aβ production through c-Jun N-terminal kinase (JNK)-dependent activation of γ-secretase. Treatment with H2O2 induced significant increase in the levels of intracellular and secreted Aβ in human neuroblastoma SH-SY5Y cells. Although γ-secretase-mediated cleavage of APP or C99 was enhanced upon H2O2 treatment, expression of APP or its α/β-secretase-mediated cleavage was not affected. Silencing of the stress-activated JNK by small interfering RNA or the specific JNK inhibitor SP600125 reduced H2O2-induced γ-secretase-mediated cleavage of APP. JNK activity was augmented in human brain tissues from AD patients and active JNK located surrounding the senile plaques in the brain of AD model mouse. Our data suggest that oxidative stress-activated JNK may contribute to senile plaque expansion through the promotion of γ-secretase-mediated APP cleavage and Aβ production. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
246. Dynamics of a Upright Pole Coupled with Nonlinear Hysteretic Isolators under Harmonic Base Excitation
- Author
-
Yongfeng Cheng, Hulun Guo, Zhubing Zhu, Xiaochao Su, and Yushu Chen
- Subjects
Physics ,QC1-999 - Abstract
Leady isolator shows hysteretic nonlinearity. The isolation efficiency of leady isolator is an important problem in many engineering structures. In this paper, vibrations of a ceramic upright pole coupled with four leady isolators under harmonic base excitation are studied. A hysteretic force-deformation model of leady isolator is derived from experimental results. With this model, the vibration of the pole in rotation is studied. The frequency response is obtained analytically by employing harmonic balance method. The analytical results are agreed well with numerical results. The vibration of the pole is decreased greatly by leady isolator, especially near resonant case. The influences of system parameters on vibration response and resonant peak are discussed in detail.
- Published
- 2018
- Full Text
- View/download PDF
247. Retinoic acid liposome-hydrogel: preparation, penetration through mouse skin and induction of F9 mouse teratocarcinoma stem cells differentiation
- Author
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Hongmei Xia, Yongfeng Cheng, Yinxiang Xu, and Zhiqing Cheng
- Subjects
Ácido retinóico (RA) ,RA lipossoma-hidrogel/características ,RA lipossoma-hidrogel/preparação ,RA lipossoma-hidrogel/difusão/estudo experimental ,Células F9/diferenciação ,Pharmacy and materia medica ,RS1-441 - Abstract
Retinoic acid (RA), a metabolite of retinol, is one of the most biologically active forms of retinoid and plays vital roles in embryonic development and in the regulation of cell proliferation and differentiation. Knowing that liposomes simulate cell membranes and that hydrogel is an ideal delivery vehicle for topical medicine, liposome-hydrogel is a novel preparation that has synergistic advantages over each component separately. Our objective was to investigate the characteristics of RA liposome-hydrogel. For quality control of the RA-loaded liposomes, we measured their morphology, particle size, Zeta-potential, and entrapment efficiency. Then we determined the viscosity of RA liposome-hydrogel. Next, the diffusion through mouse skin was explored, followed by investigation of the mRNA expression levels of Ker18, REX1, and α-FP using Q-PCR. The results showed that RA liposome-hydrogel penetrates the mouse skin effectively. The permeation rates were: Qn (%) of RA liposome-hydrogel < Qn(%) of RA-loaded liposome < Qn (%) of RA. The mRNA expression levels were dose-dependent and the effective dose decreased between vehicles due to their different release rates. F9 mouse teratocarcinoma stem cells were an ideal model to explore the mechanism of RA liposome-hydrogel in stem cell differentiation.
- Published
- 2015
- Full Text
- View/download PDF
248. Exome sequencing in a Chinese family reveals TTC9 mutation associated with keratitis-ichthyosis-deafness (KID) syndrome.
- Author
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Xiaohua WANG, Xueli WU, Baoqing ZHENG, Yongfeng CHEN, and Daocheng ZHENG
- Published
- 2018
- Full Text
- View/download PDF
249. Visible-infrared dual-mode MoS2-graphene-MoS2 phototransistor with high ratio of the I ph/I dark.
- Author
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Wenjie Deng, Yongfeng Chen, Congya You, Boxing An, Beiyun Liu, Songyu Li, Yongzhe Zhang, Hui Yan, and Ling Sun
- Published
- 2018
- Full Text
- View/download PDF
250. The Zinc Finger Transcription Factor Ovol2 Acts Downstream of the Bone Morphogenetic Protein Pathway to Regulate the Cell Fate Decision between Neuroectoderm and Mesendoderm.
- Author
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Ting Zhang, Qingqing Zhu, Zhihui Xie, Yongfeng Chen, Yunbo Qiao, Lingyu Li, and Naihe Jing
- Subjects
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ZINC-finger proteins , *BONE morphogenetic proteins , *TRANSCRIPTION factors , *CELL differentiation , *ENDODERM , *MESODERM , *EMBRYONIC stem cells , *MAMMALS - Abstract
During early embryonic development, bone morphogenetic protein (BMP) signaling is essential for neural/non-neural cell fate decisions. BMP signaling inhibits precocious neural differentiation and allows for proper differentiation of mesoderm, endoderm, and epidermis. However, the mechanisms underlying theBMPpathway-mediated cell fate decision remain largely unknown. Here, we show that the expression of Ovol2, which encodes an evolutionarily conserved zinc finger transcription factor, is down-regulated during neural differentiation of mouse embryonic stem cells. Knockdown of Ovol2 in embryonic stem cells facilitates neural conversion and inhibits mesendodermal differentiation, whereas Ovol2 overexpression gives rise to the opposite phenotype. Moreover, Ovol2 knockdown partially rescues the neural inhibition and mesendodermal induction by BMP4. Mechanistic studies further show that BMP4 directly regulates Ovol2 expression through the binding of Smad1/5/8 to the second intron of the Ovol2 gene. In the chick embryo, cOvol2 expression is specifically excluded from neural territory and is up-regulated by BMP4. In addition, ectopic expression of cOvol2 in the prospective neural plate represses the expression of the definitive neural plate marker cSox2. Taken together, these results indicate that Ovol2 acts downstream of the BMP pathway in the cell fate decision between neuroectoderm and mesendoderm to ensure proper germ layer development. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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