24 results on '"Shirong Li"'
Search Results
2. Tigecycline in the Treatment of Ventilator-Associated Pneumonia Due to Stenotrophomonas maltophilia: A Multicenter Retrospective Cohort Study
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Shirong Li, Lingling Pan, Dayan Zhang, Xiang Li, Gang Yang, Lei Zha, Shuangqi Luo, Zhichu Ren, Boris Tefsen, and Yi Zou
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Microbiology (medical) ,medicine.medical_specialty ,Multicenter retrospective cohort study ,Stenotrophomonas maltophilia ,Moxifloxacin ,Levofloxacin ,Tigecycline ,Internal medicine ,medicine ,Ventilator-associated pneumonia ,Original Research ,biology ,business.industry ,Retrospective cohort study ,bacterial infections and mycoses ,biology.organism_classification ,medicine.disease ,respiratory tract diseases ,Pneumonia ,Infectious Diseases ,business ,Empiric therapy ,Fluoroquinolones ,medicine.drug - Abstract
Introduction Tigecycline is a potential alternative to trimethoprim–sulfamethoxazole in treating Stenotrophomonas maltophilia infections due to its potent in vitro antimicrobial activity. Clinical evidence regarding the use of tigecycline in the treatment of S. maltophilia infections is scarce. In this study, we assessed the efficacy of tigecycline treating ventilator-associated pneumonia (VAP) due to S. maltophilia in comparison with fluoroquinolones. Methods This is a multicenter retrospective cohort study of patients admitted between January 2017 and December 2020 with the diagnosis of VAP caused by S. maltophilia receiving either tigecycline or fluoroquinolones as the definitive therapy ≥ 48 h. Clinical outcomes including 28-day mortality, clinical cure and microbiological cure were analyzed. Results Of 82 patients with S. maltophilia VAP included, 46 received tigecycline, and 36 received fluoroquinolones; 70.7% of patients had polymicrobial pneumonia, and the appropriate empiric therapy was applied to only 14.6% of patients. The overall 28-day mortality was 39%. Compared with patients receiving fluoroquinolones, tigecycline therapy resulted in worse clinical cure (32.6% vs. 63.9%, p = 0.009) and microbiological cure (28.6% vs. 59.1%, p = 0.045), while there was no statistical difference between 28-day mortality (47.8% vs. 27.8%, p = 0.105) in the two groups. Similar results were also shown in the inverse probability of treatment weighted univariable regression model and multivariable regression model. Conclusions The standard dose of tigecycline therapy was associated with a lower clinical and microbiological cure rate but not associated with an increased 28-day mortality in patients with S. maltophilia VAP compared with fluoroquinolones. Considering the unfavorable clinical outcomes, we therefore recommend against using the standard dose of tigecycline in treating S. maltophilia VAP unless new clinical evidence emerges. Supplementary Information The online version contains supplementary material available at 10.1007/s40121-021-00516-5.
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- 2021
3. Experimental and Theoretical Research on Low-Strength Concrete Beams Reinforced with Basalt Fibre-Reinforced Plastic Sheets in a Freeze–Thaw Environment
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Shirong Li, Genli Ren, Zaiping Zeng, and Xiuli Wang
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Multidisciplinary ,Materials science ,Ultimate tensile strength ,Bearing capacity ,Bending ,Composite material ,Fibre-reinforced plastic ,Softening ,Failure mode and effects analysis ,Finite element method ,Beam (structure) - Abstract
Basalt fibre-reinforced plastic sheet (BFRP) enhancement is one of the strengthening methods suitable for concrete structures due to the low price and high tensile strength of BFRPs. It is of great importance to study the mechanical performance of BFRP-reinforced low-strength concrete structures in freeze–thaw environments. Therefore, 15 concrete beam specimens were designed, and a fast freeze–thaw experiment was conducted in this research to consider different parameters, such as the number of freeze–thaw cycles, sequence of freezing–thawing and BFRP pasting and other factors. The mechanical performance of low-strength concrete beams reinforced with BFRPs under freeze–thaw cycles was investigated. The failure mode and load–deflection curves of specimens were also analysed. The test results revealed that the ultimate strength of concrete beams reinforced with BFRPs was greatly improved, with a maximum increase of 32.7%. With increasing number of freeze–thaw cycles, the ultimate strength of beams gradually decreased over the bearing capacity of non-frozen-thawed concrete beams reinforced with BFRPs (F0b), and the bearing capacity of low-strength concrete beams reinforced with BFRPs decreased 17.1% after 50 continuous freeze–thaw cycles, while the beam failure mode changed from bending failure to shear failure accompanied by de-bonding failure. A mechanical model of BFRP-reinforced low-strength concrete beams was constructed under the de-bonding failure mode, and a calculation equation to determine the magnitude of de-bonding failure was proposed. Finally, finite element analysis of specimens was performed with cohesive elements to simulate the nonlinear softening mechanical behaviour of the BFRP–concrete interface.
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- 2021
4. Laccase-Mediated In Situ Oxidation of Dopamine for Dyeing of Human Hair
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Zhang Xiaoli, Zhijie Liang, Weini Jia, Aixue Dong, Hainan Yu, Zhengxin Luo, Shirong Li, Wenjun Zhu, and Mao Qinghui
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Laccase ,chemistry.chemical_classification ,Materials science ,integumentary system ,Polymers and Plastics ,Scanning electron microscope ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Polymerization ,Covalent bond ,otorhinolaryngologic diseases ,Hydroxyl radical ,sense organs ,Dyeing ,0210 nano-technology - Abstract
Due to the damage of scalp because of chemical dyes, increasing attention had been paid to the ecological dyeing of human hair. To address the need for ecological restoration and dyeing of human hair, herein, a novel approach has been proposed via laccase-mediated in situ oxidation of dihydroxy phenylalanine (dopamine). As laccase can catalyze dopamine oxidation and then polymerization to produce strongly colored polymers, different biological coloration processes of human hair based on this process were investigated: (i) Human hair was treated with laccase alone; (ii) The absorption of human hair with dopamine, followed by further catalysis of air; (iii) The absorption of human hair with dopamine, followed by further catalysis of laccase; (iv) Simultaneous laccase-mediated polymerization and dyeing of human hair; and (v) Polymerization of Dopamine with laccase and then dyeing human hair. The surface properties of dyed hair were evaluated in terms of ultraviolet (UV)-protection, color fastness, Fourier transforming infrared spectrum (FT-IR), optical microscope, and scanning electron microscopy (SEM). The results show that best hair dyeing effect was achieved via simultaneous laccase-mediated polymerization and dyeing. The dyed hair obtained K/S values of 28, light fastness of level 5, and UPF of 100+. The optical microscope and SEM observations show that the surface of colored hair fibers was covered with thin burrs, which can be attributed to polydopamine attached with physical adhesive force and covalent reaction. FT-IR analysis shows that functional groups were present on the surface of the dyed hair which can be considered as introduction of hydroxyl radical groups. This biological stain technique may be widely used in dyeing of hair with black color.
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- 2021
5. Thermoelastic Damping of Functionally Graded Material Micro-Beam Resonators Based on the Modified Couple Stress Theory
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Shirong Li and Zhichao Zhang
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Timoshenko beam theory ,Materials science ,Mechanical Engineering ,Computational Mechanics ,Natural frequency ,02 engineering and technology ,Mechanics ,Dissipation ,021001 nanoscience & nanotechnology ,Functionally graded material ,Vibration ,020303 mechanical engineering & transports ,Thermoelastic damping ,0203 mechanical engineering ,Mechanics of Materials ,Boundary value problem ,0210 nano-technology ,Material properties - Abstract
Thermoelastic damping (TED) is one of the main internal energy dissipation mechanisms in micro-/nano-resonators. Accurate evaluation of TED is important in the design of micro-electromechanical systems and nano-electromechanical systems. In this paper, a theoretical analysis on the TED in functionally graded material (FGM) micro-beam resonators is presented. Equations of motion and the heat conduction equation governing the thermodynamic coupling free vibration of non-homogenous micro-beams are established based on the Euler–Bernoulli beam theory associated with the modified couple stress theory. Material properties of the FGM micro-beam are assumed to change in the depth direction as power-law functions. The layer-wise homogenization method is used for solving the heat conduction equation. By using the mathematical similarity of eigenvalue problem between the FGM beam and the reference homogeneous one, the complex natural frequency including TED is expressed in terms of the natural frequency of the isothermal homogenous beam. In the presented numerical results, influences of various characteristic parameters, such as beam thickness, material gradient index, structure size, vibration mode and boundary conditions, on TED are examined in detail. It shows that TED decreases with the increases in the values of length scale parameters because the latter lead to the increase in structural stiffness.
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- 2020
6. Bending Solutions of FGM Reddy–Bickford Beams in Terms of Those of the Homogenous Euler–Bernoulli Beams
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Ze-Qing Wan, Shirong Li, and You-Ming Xia
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Physics ,Timoshenko beam theory ,Mechanical Engineering ,Mathematical analysis ,Computational Mechanics ,02 engineering and technology ,Bending ,021001 nanoscience & nanotechnology ,Functionally graded material ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mechanics of Materials ,Deflection (engineering) ,Stress resultants ,Bending moment ,Physics::Accelerator Physics ,Boundary value problem ,0210 nano-technology ,Beam (structure) - Abstract
In this paper, correspondence relations between the solutions of the static bending of functionally graded material (FGM) Reddy–Bickford beams (RBBs) and those of the corresponding homogenous Euler–Bernoulli beams are presented. The effective material properties of the FGM beams are assumed to vary continuously in the thickness direction. Governing equations for the titled problem are formulated via the principle of virtual displacements based on the third-order shear deformation beam theory, in which the higher-order shear force and bending moment are included. General solutions of the displacements and the stress resultants of the FGM RBBs are derived analytically in terms of the deflection of the reference homogenous Euler–Bernoulli beam with the same geometry, loadings and end conditions, which realize a classical and homogenized expression of the bending response of the shear deformable non-homogeneous FGM beams. Particular solutions for the FGM RBBs under specified end constraints and load conditions are given to validate the theory and methodology. The key merit of this work is to be capable of obtaining the high-accuracy solutions of thick FGM beams in terms of the classical beam theory solutions without dealing with the solution of the complicated coupling differential equations with boundary conditions of the problem.
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- 2019
7. Groups All Cyclic Subgroups of Which are BNA-Subgroups
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Shirong Li, X. He, and Yanming Wang
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Combinatorics ,Finite group ,General Mathematics ,010102 general mathematics ,0103 physical sciences ,010307 mathematical physics ,0101 mathematics ,Algebra over a field ,01 natural sciences ,Mathematics - Abstract
Suppose that G is a finite group and H is a subgroup of G. We say that H is a BNA-subgroup of G if either H x = H or x ∈ for all x ∈ G. The BNA-subgroups of G are between normal and abnormal subgroups of G. We obtain some new characterizations for finite groups based on the assumption that all cyclic subgroups are BNA-subgroups.
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- 2017
8. A Selenium-Enriched Ziyang Green Tea Polysaccharide Induces Bax-Dependent Mitochondrial Apoptosis and Inhibits TGF-β1-Stimulated Collagen Expression in Human Keloid Fibroblasts via NG2 Inactivation
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Wenping Wang, Lele Lu, Shirong Li, Yuan Xi, Linlin Chai, and Chuan Cao
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0301 basic medicine ,Endocrinology, Diabetes and Metabolism ,Clinical Biochemistry ,Apoptosis ,Biochemistry ,Transforming Growth Factor beta1 ,Inorganic Chemistry ,Extracellular matrix ,Small hairpin RNA ,Selenium ,03 medical and health sciences ,chemistry.chemical_compound ,Keloid ,Polysaccharides ,Annexin ,medicine ,Humans ,Propidium iodide ,Antigens ,skin and connective tissue diseases ,Cells, Cultured ,bcl-2-Associated X Protein ,Neurons ,Tea ,Biochemistry (medical) ,General Medicine ,Fibroblasts ,medicine.disease ,Molecular biology ,Mitochondria ,030104 developmental biology ,chemistry ,Proteoglycans ,Collagen ,Type I collagen ,Transforming growth factor - Abstract
Keloids are fibroproliferative disorders characterized by the overabundant deposition of extracellular matrix (ECM), especially collagen and overgrowth of scar tissue in response to cutaneous injury. In this study, we isolated a selenium (Se)-containing polysaccharide (Se-ZGTP-I) from Ziyang green tea and explored its potential therapeutic effects on keloid fibroblasts formation. 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and annexin V/propidium iodide (PI) staining assays demonstrated that Se-ZGTP-I or neuron-glia 2 (NG2) short hairpin RNA (shRNA) significantly inhibited proliferation of human keloid fibroblasts via induction of apoptosis. Besides, the activation of caspase-3 and the subsequent cleavage of poly (ADP-ribose) polymerase (PARP) were observed in keloid fibroblasts following Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA treatment. Moreover, Western blotting analysis showed that treatment of keloid fibroblasts with Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA resulted in an increase of pro-apoptotic protein Bax expression and a decrease in expression levels of anti-apoptotic protein Bcl-2 and NG2. In addition, type I collagen biosynthesis and protein expression in keloid fibroblasts following TGF-β1 stimulation were decreased by Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA management. Current findings imply that Se-ZGTP-I has a therapeutic potential to intervene and prevent keloid formation and other fibrotic diseases.
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- 2016
9. Down-Regulation of ClC-3 Expression Reduces Epidermal Stem Cell Migration by Inhibiting Volume-Activated Chloride Currents
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Rui Guo, Fuqiang Pan, Yanping Tian, Shirong Li, Chuan Cao, and Hongli Li
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Male ,0301 basic medicine ,Physiology ,Genetic Vectors ,Biophysics ,Gene Expression ,Biology ,Cell Line ,03 medical and health sciences ,0302 clinical medicine ,Chlorides ,Cell Movement ,Chloride Channels ,Transduction, Genetic ,Live cell imaging ,medicine ,Animals ,Humans ,RNA, Messenger ,Skin repair ,urogenital system ,Cell growth ,Stem Cells ,Lentivirus ,Cell migration ,Cell Biology ,Hair follicle ,Rats ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,Epidermal Cells ,Cell culture ,Chloride channel ,RNA Interference ,Epidermis ,Stem cell ,030217 neurology & neurosurgery - Abstract
ClC-3, a member of the ClC chloride (Cl(-)) channel family, has recently been proposed as the primary Cl(-) channel involved in cell volume regulation. Changes in cell volume influence excitability, contraction, migration, pathogen-host interactions, cell proliferation, and cell death processes. In this study, expression and function of ClC-3 channels were investigated during epidermal stem cell (ESC) migration. We observed differential expression of CLC-3 regulates migration of ESCs. Further, whole-cell patch-clamp recordings and image analysis demonstrated ClC-3 expression affected volume-activated Cl(-) current (I Cl,Vol) within ESCs. Live cell imaging systems, designed to observe cellular responses to overexpression and suppression of ClC-3 in real time, indicated ClC-3 may regulate ESC migratory dynamics. We employed IMARIS software to analyze the velocity and distance of ESC migration in vitro to demonstrate the function of ClC-3 channel in ESCs. As our data suggest volume-activated Cl(-) channels play a vital role in migration of ESCs, which contribute to skin repair by migrating from neighboring unwounded epidermis infundibulum, hair follicle or sebaceous glands, ClC-3 may represent a new and valuable target for stem cell therapies.
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- 2016
10. Classical and homogenized expressions for buckling solutions of functionally graded material Levinson beams
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Shirong Li, Xuan Wang, and Ze-Qing Wan
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Timoshenko beam theory ,Critical load ,business.industry ,Mechanical Engineering ,Mathematical analysis ,Computational Mechanics ,Structural engineering ,Functionally graded material ,Buckling ,Mechanics of Materials ,Deflection (engineering) ,Ordinary differential equation ,Boundary value problem ,business ,Beam (structure) ,Mathematics - Abstract
The relationship between the critical buckling loads of functionally graded material (FGM) Levinson beams (LBs) and those of the corresponding homogeneous Euler-Bernoulli beams (HEBBs) is investigated. Properties of the beam are assumed to vary continuously in the depth direction. The governing equations of the FGM beam are derived based on the Levinson beam theory, in which a quadratic variation of the transverse shear strain through the depth is included. By eliminating the axial displacement as well as the rotational angle in the governing equations, an ordinary differential equation in terms of the deflection of the FGM LBs is derived, the form of which is the same as that of HEBBs except for the definition of the load parameter. By solving the eigenvalue problem of ordinary differential equations under different boundary conditions clamped (C), simply-supported (S), roller (R) and free (F) edges combined, a uniform analytical formulation of buckling loads of FGM LBs with S-S, C-C, C-F, C-R and S-R edges is presented for those of HEBBs with the same boundary conditions. For the C-S beam the above-mentioned equation does not hold. Instead, a transcendental equation is derived to find the critical buckling load for the FGM LB which is similar to that for HEBB with the same ends. The significance of this work lies in that the solution of the critical buckling load of a FGM LB can be reduced to that of the HEBB and calculation of three constants whose values only depend upon the through-the-depth gradient of the material properties and the geometry of the beam. So, a homogeneous and classical expression for the buckling solution of FGM LBs is accomplished.
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- 2015
11. Life-history responses of insects to water-deficit stress: a case study with the aphid Sitobion avenae
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Shirong Li, Xiaoqin Shi, Peng Dai, Syed Suhail Ahmed, Zheming Shang, and Deguang Liu
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0106 biological sciences ,China ,Climate Change ,Adaptation, Biological ,010603 evolutionary biology ,01 natural sciences ,Life-history traits ,Sitobion avenae ,Animals ,Nymph ,Life History Traits ,QH540-549.5 ,Ecology, Evolution, Behavior and Systematics ,General Environmental Science ,Aphid ,Drought ,Ecology ,biology ,Global warming ,Body Weight ,fungi ,food and beverages ,Heritability ,Fecundity ,biology.organism_classification ,Arid ,Droughts ,Genetic divergence ,010602 entomology ,Fertility ,Agronomy ,Aphids ,Adaptation potential ,Seasons ,Adaptation ,Water-deficit stress ,Research Article - Abstract
Background Drought may become one of the greatest challenges for cereal production under future warming scenarios, and its impact on insect pest outbreaks is still controversial. To address this issue, life-history responses of the English grain aphid, Sitobion avenae (Fabricius), from three areas of different drought levels were compared under three water treatments. Results Significant differences were identified in developmental time, fecundity and adult weight among S. avenae clones from moist, semiarid and arid areas under all the three water treatments. Semiarid and arid area clones tended to have higher heritability for test life-history traits than moist area clones. We identified significant selection of water-deficit on the developmental time of 1st instar nymphs and adult weight for both semiarid and arid area clones. The impact of intermediate and severe water-stress on S. avenae’s fitness was neutral and negative (e.g., decreased fecundity and weight), respectively. Compared with arid-area clones, moist- and semiarid-area clones showed higher extents of adaptation to the water-deficit level of their respective source environment. Adult weight was identified as a good indicator for S. avenae’s adaptation potential under different water-stress conditions. After their exposure to intermediate water-deficit stress for only five generations, adult weight and fecundity tended to decrease for moist- and semiarid-area clones, but increase for arid-area clones. Conclusions It is evident from our study that S. avenae clones from moist, semiarid and arid areas have diverged under different water-deficit stress, and such divergence could have a genetic basis. The impact of drought on S. avenae’s fitness showed a water-level dependent pattern. Clones of S. avenae were more likely to become adapted to intermediate water-deficit stress than severe water-deficit stress. After continuous water-deficit stress of only five generations, the adaptation potential of S. avenae tended to decrease for moist and semiarid area clones, but increase for arid area clones. The rapid shift of aphids’ life-history traits and adaptation potential under drought could have significant implications for their evolutionary dynamics and outbreak risks in future climate change scenarios. Electronic supplementary material The online version of this article (10.1186/s12898-018-0173-0) contains supplementary material, which is available to authorized users.
- Published
- 2018
12. Homogenized and classical expressions for static bending solutions for functionally graded material Levinson beams
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Xuan Wang, Shirong Li, and Zeqing Wan
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Timoshenko beam theory ,Applied Mathematics ,Mechanical Engineering ,Mathematical analysis ,Shear force ,Geometry ,Functionally graded material ,Mechanics of Materials ,Deflection (engineering) ,Bending stiffness ,Bending moment ,Physics::Accelerator Physics ,Boundary value problem ,Material properties ,Mathematics - Abstract
The exact relationship between the bending solutions of functionally graded material (FGM) beams based on the Levinson beam theory and those of the corresponding homogenous beams based on the classical beam theory is presented for the material properties of the FGM beams changing continuously in the thickness direction. The deflection, the rotational angle, the bending moment, and the shear force of FGM Levinson beams (FGMLBs) are given analytically in terms of the deflection of the reference homogenous Euler-Bernoulli beams (HEBBs) with the same loading, geometry, and end supports. Consequently, the solution of the bending of non-homogenous Levinson beams can be simplified to the calculation of transition coefficients, which can be easily determined by variation of the gradient of material properties and the geometry of beams. This is because the classical beam theory solutions of homogenous beams can be easily determined or are available in the textbook of material strength under a variety of boundary conditions. As examples, for different end constraints, particular solutions are given for the FGMLBs under specified loadings to illustrate validity of this approach. These analytical solutions can be used as benchmarks to check numerical results in the investigation of static bending of FGM beams based on higher-order shear deformation theories.
- Published
- 2015
13. Stromal cell-derived factor 1 (SDF-1) accelerated skin wound healing by promoting the migration and proliferation of epidermal stem cells
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Shirong Li, Ge Liangpeng, Hongli Li, Chen Liang, Wenguang Chen, Chuan Cao, Li Xiaoge, Rui Guo, and Linlin Chai
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Male ,Receptors, CXCR4 ,Biology ,CXCR4 ,Rats, Sprague-Dawley ,Cell Movement ,medicine ,Animals ,Stromal cell-derived factor 1 ,Cell Proliferation ,Skin repair ,Wound Healing ,integumentary system ,Epidermis (botany) ,Stem Cells ,Regeneration (biology) ,Cell Biology ,General Medicine ,Hair follicle ,Immunohistochemistry ,Chemokine CXCL12 ,Up-Regulation ,Cell biology ,medicine.anatomical_structure ,Immunology ,biology.protein ,Epidermis ,Stem cell ,Wound healing ,Developmental Biology - Abstract
Epidermal stem cells could contribute to skin repair through the migration of cells from the neighboring uninjured epidermis, infundibulum, hair follicle, or sebaceous gland. However, little is known about the factors responsible for the complex biological processes in wound healing. Herein, we will show that the attracting chemokine, SDF-1/CXCR4, is a major regulator involved in the migration of epidermal stem cells during wound repair. We found that the SDF-1 levels were markedly increased at the wound margins following injury and CXCR4 expressed in epidermal stem cells and proliferating epithelial cells. Blocking the SDF-1/CXCR4 axis resulted in a significant reduction in epidermal stem cell migration toward SDF-1 in vitro and delayed wound healing in vivo, while an SDF-1 treatment enhanced epidermal stem cell migration and proliferation and accelerated wound healing. These results provide direct evidence that SDF-1 promotes epidermal stem cell migration, accelerates skin regeneration, and makes the development of new regenerative therapeutic strategies for wound healing possible.
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- 2015
14. Over-expression of BAG-1 in head and neck squamous cell carcinomas (HNSCC) is associated with cisplatin-resistance
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David F. Stroncek, Hang Gao, Ping Jin, Qinghua Zeng, Shirong Li, Xue-Jin Su, Suchan Liao, Yu-Lin Li, Zhi-Xiang Xu, Ying-Xian Zhai, Bo Ren, and Shutong Liu
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0301 basic medicine ,Oncology ,medicine.medical_specialty ,Cell Survival ,Cell ,lcsh:Medicine ,BAG-1 ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,0302 clinical medicine ,Cell Line, Tumor ,Internal medicine ,Gene expression ,medicine ,Humans ,Cisplatin ,Squamous Cell Carcinoma of Head and Neck ,business.industry ,Research ,lcsh:R ,Head and neck squamous cell carcinomas ,Reproducibility of Results ,Biomarker ,General Medicine ,medicine.disease ,Head and neck squamous-cell carcinoma ,Up-Regulation ,DNA-Binding Proteins ,Gene Expression Regulation, Neoplastic ,stomatognathic diseases ,030104 developmental biology ,medicine.anatomical_structure ,Drug Resistance, Neoplasm ,Head and Neck Neoplasms ,Tumor progression ,Cell culture ,Drug resistance ,BCL-xL ,030220 oncology & carcinogenesis ,Carcinoma, Squamous Cell ,Biomarker (medicine) ,DNA microarray ,business ,Signal Transduction ,Transcription Factors ,medicine.drug - Abstract
Background In order to improve therapy for head and neck squamous cell carcinoma (HNSCC), biomarkers associated with local and/or distant tumor relapses and cancer drug resistance are urgently needed. This study identified a potential biomarker, Bcl-2 associated athanogene-1 (BAG-1), that is implicated in HNSCC insensitive to cisplatin and tumor progression. Methods Primary and advanced (relapsed from parental) University of Michigan squamous cell carcinoma cell lines were tested for sensitivity to cisplatin and gene expression profiles were compared between primary (cisplatin sensitive) and the relapsed (cisplatin resistant) cell lines by using Agilent microarrays. Additionally, differentially expressed genes phosphorylated AKT, and BAG-1, and BCL-xL were evaluated for expression using HNSCC tissue arrays. Results Advanced HNSCC cells revealed resistant to cisplatin accompanied by increased expression of BAG-1 protein. siRNA knockdown of BAG-1 expression resulted in significant improvement of HNSCC sensitivity to cisplatin. BAG-1 expression enhanced stability of BCL-xL and conferred cisplatin resistant to the HNSCC cells. In addition, high levels of expression of phosphorylated AKT, BAG-1, and BCL-xL were observed in advanced HNSCC compared to in that of primary HNSCC. Conclusion Increased expression of BAG-1 was associated with cisplatin resistance and tumor progression in HNSCC patients and warrants further validation in larger independent studies. Over expression of BAG-1 may be a biomarker for cisplatin resistance in patients with primary or recurrent HNSCCs and targeting BAG-1 could be helpful in overcoming cisplatin resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12967-017-1289-2) contains supplementary material, which is available to authorized users.
- Published
- 2017
15. On weakly closed subgroups of finite groups
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Yingyi Chen, Zhencai Shen, and Shirong Li
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Combinatorics ,Finite group ,General Mathematics ,Sylow theorems ,Structure (category theory) ,Order (ring theory) ,Nilpotent group ,Mathematics - Abstract
Suppose that \(G\) is a finite group and \(H\), \(K\) are subgroups of \(G\). We say that \(H\) is weakly closed in \(K\) with respect to \(G\) if, for any \(g \in G\) such that \(H^{g}\le K\), we have \(H^{g}=H\). In particular, when \(H\) is a subgroup of prime-power order and \(K\) is a Sylow subgroup containing it, \(H\) is simply said to be a weakly closed subgroup of \(G\) or weakly closed in \(G\). In the paper, we investigate the structure of finite groups by means of weakly closed subgroups.
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- 2014
16. Free vibration of FGM Timoshenko beams with through-width delamination
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ShiRong Li and LiangLiang Fan
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Timoshenko beam theory ,Materials science ,Delamination ,Mathematical analysis ,General Physics and Astronomy ,Natural frequency ,Computer Science::Numerical Analysis ,Mathematics::Numerical Analysis ,Quadrature (mathematics) ,Vibration ,Ordinary differential equation ,Physics::Accelerator Physics ,Beam (structure) ,Eigenvalues and eigenvectors - Abstract
Free vibration of functionally graded beams with a through-width delamination is investigated. It is assumed that the material property is varied in the thickness direction as power law functions and a single through-width delamination is located parallel to the beam axis. The beam is subdivided into three regions and four elements. Governing equations of the beam segments are derived based on the Timoshenko beam theory and the assumption of ‘constrained mode’. By using the differential quadrature element method to solve the eigenvalue problem of ordinary differential equations governing the free vibration, numerical results for the natural frequencies of the beam are obtained. Natural frequencies of delaminated FGM beam with clamped ends are presented. Effects of parameters of the material gradients, the size and location of delamination on the natural frequency are examined in detail.
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- 2014
17. PTEN inhibits proliferation and functions of hypertrophic scar fibroblasts
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Chen Liang, Linlin Chai, Sheng Bi, Zengxiang Wang, Chuan Cao, Ling Tao, Guo Liang, and Shirong Li
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Adult ,Male ,Adolescent ,Cicatrix, Hypertrophic ,Clinical Biochemistry ,Gene Expression ,Apoptosis ,Biology ,Young Adult ,Hypertrophic scar ,Western blot ,medicine ,Humans ,Tensin ,PTEN ,Phosphorylation ,Child ,Molecular Biology ,Protein kinase B ,Cells, Cultured ,PI3K/AKT/mTOR pathway ,Cell Proliferation ,medicine.diagnostic_test ,Cell growth ,PTEN Phosphohydrolase ,Cell Biology ,General Medicine ,Fibroblasts ,Middle Aged ,medicine.disease ,Molecular biology ,Recombinant Proteins ,Reverse transcription polymerase chain reaction ,Cancer research ,biology.protein ,Female ,Collagen ,Proto-Oncogene Proteins c-akt ,Signal Transduction - Abstract
Hypertrophic scar (HS) remains a major problem in plastic surgery. In order to explore the regulative effect of phosphatase and tensin homolog (PTEN) on HS, PTEN and AKT expression was detected by reverse transcription PCR, immunohistochemistry and western blot. Adenovirus-mediated PTEN overexpression in cultured hypertrophic scar fibroblasts (HSFBs) and normal skin fibroblasts was also introduced to evaluate its biological function. Our results showed that PTEN expression was significantly decreased in HS whereas p-Akt level was significantly higher in HS compared with normal skin (P < 0.01). Furthermore, we found that adenovirus-mediated PTEN overexpression led to decreased AKT activation, and significantly reduced cell proliferation and collagen synthesis of HSFBs, while increased the apoptosis. Taken together, these data suggest that PTEN inhibits proliferation and function of HSFBs through AKT pathway. Our results reveal a novel biological role for PTEN/AKT pathway in HS and suggest PTEN as a potential therapeutic target for HS treatment.
- Published
- 2011
18. Finite groups with some CAP-subgroups
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Shirong Li, Zhengcai Shen, Jianjun Liu, and Xiaochun Liu
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Combinatorics ,p-group ,Discrete mathematics ,Finite group ,Subgroup ,Group (mathematics) ,Applied Mathematics ,General Mathematics ,Sylow theorems ,Prime factor ,Index of a subgroup ,Nilpotent group ,Mathematics - Abstract
Let G be a finite group. A subgroup H of G is called a CAP-subgroup if the following condition is satisfied: for each chief factor K/L of G either HK = HL or H ∩ K = H ∩ L. Let p be a prime factor of |G| and let P be a Sylow p-subgroup of G. If d is the minimum number of generators of P then there exists a family of maximal subgroups of P, denoted by Md(P)={P1, P2,…, Pd} such that ∩i=1dPi= ϕ(P). In this paper, we investigate the group G satisfying the condition: every member of a fixed Md(P) is a CAP-subgroup of G. For example, if, in addition, G is p-solvable, then G is p-supersolvable.
- Published
- 2011
19. Classification of finite groups satisfying a minimal condition
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Wei Meng and Shirong Li
- Subjects
Normal subgroup ,Combinatorics ,Discrete mathematics ,Maximal subgroup ,Torsion subgroup ,Subgroup ,Locally finite group ,General Mathematics ,Characteristic subgroup ,Index of a subgroup ,Fitting subgroup ,Mathematics - Abstract
If H is a subgroup of a finite group G then we denote the normal closure of H in G by HG. We call G a PE-group if every minimal subgroup X of G satisfies NG(X) ∩ XG = X. The authors classify the finite non-PE-groups whose maximal subgroups of even order are PE-groups.
- Published
- 2009
20. ℱ-subnormal and ℱ-subabnormal chains in finite groups
- Author
-
Shirong Li
- Subjects
Discrete mathematics ,Class (set theory) ,Pure mathematics ,Locally finite group ,General Mathematics ,Existential quantification ,Mathematics - Abstract
The class ℱpc of all finite groupsG is defined such thatX≤G implies that there exists an ℱ-subnormal subgroupS ofG containingX such thatX is ℱ-subabnormal inS, where ℱ is a saturated formation, closed under taken subgroups. Groups in ℱpc are characterized by ℱ-projectors and ℱ-covering subgroups.
- Published
- 1998
21. Analysis of thermal post-buckling of heated elastic rods
- Author
-
Shirong, Li, primary and Changjun, Cheng, additional
- Published
- 2000
- Full Text
- View/download PDF
22. Finite groups with exactly two class lengths of elements of prime power order
- Author
-
Shirong, Li, primary
- Published
- 1996
- Full Text
- View/download PDF
23. Finite groups with a condition on the indices of maximal subgroups
- Author
-
Shirong, Li, primary
- Published
- 1991
- Full Text
- View/download PDF
24. Some finite nonsolvable groups characterized by their solvable subgroups
- Author
-
Shirong, Li, primary and Yaoqing, Zhao, additional
- Published
- 1988
- Full Text
- View/download PDF
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