An investigation of gaseous elemental mercury concentration in atmosphere was conducted at Beijing and Guangzhou urban, Yangtze Delta regional sites and China Global Atmosphere Watch Baseline Observatory （CGAWBO） in...An investigation of gaseous elemental mercury concentration in atmosphere was conducted at Beijing and Guangzhou urban, Yangtze Delta regional sites and China Global Atmosphere Watch Baseline Observatory （CGAWBO） in Mt. Waliguan of remote continental area of China. High temporal resolved data were obtained using automated mercury analyzer RA-915^＋. Results showed that the overall hourly mean Hg^0 concentrations in Mt. Waliguan were 1.7±1.1 ng/m3 in summer and 0.6±0.08 ng/m^3 in winter. The concentration in Yangtze Delta regional site was 5.4±4.1 ng/m^3, which was much higher than those in Waliguan continental background area and also higher than that found in North America and Europe rural areas. In Beijing urban area the overall hourly mean Hg^0 concentrations were 8.3±3.6 ng/m^3 in winter, 6.5±5.2 ng/m^3 in spring, 4.9±3.3 ng/m^3 in summer, and 6.7±3.5 ng/m^3 in autumn, respectively, and the concentration was 13.5±7.1 ng/m^3 in Guangzhou site. The mean concentration reached the lowest value at 14：00 and the highest at 02：00 or 20：00 in all monitoring campaigns in Beijing and Guangzhou urban areas, which contrasted with the results measured in Yangtze Delta regional site and Mr. Waliguan. The features of concentration and diurnal variation of Hg^0 in Beijing and Guangzhou implied the importance of local anthropogenic sources in contributing to the high Hg^0 concentration in urban areas of China. Contrary seasonal variation patterns of Hg^0 concentration were found between urban and remote sites. In Beijing the highest Hg^0 concentration was in winter and the lowest in summer, while in Mt. Waliguan the Hg^0 concentration in summer was higher than that in winter. These indicated that different processes and factors controlled Hg^0 concentration in urban, regional and remote areas.展开更多
The growth rates of bainite plates in an Fe-C-Mn-Si superbainitie steel were investigated by in situ observation. The lengthening rates of ferrite bainite during both cooling and isothermal holding processes were obse...The growth rates of bainite plates in an Fe-C-Mn-Si superbainitie steel were investigated by in situ observation. The lengthening rates of ferrite bainite during both cooling and isothermal holding processes were observed and the growth rates of bainite plates nucleating at grain boundaries, within grains and on preformed bainite were measured. It is indicated that the lengthening rates of bainite plates during the cooling and isothermal processes were different, and that the growth rates of bainite plates nucleating at different types of sites also demon- strated diversity. The bainite plates initiating at [vain boundaries during cooling grew the fastest, while the plates nucleating on preformed bainite did the slowest. However, the growth rate of the bainite plates nucleating at grain boundaries during isothermal transformation de- creased the most, whereas the bainite plates initiating within grains grew the fastest. In addition, the growth rate of ferrite bainite in the study supported the diffusion transformation mechanism of bainite from the viewooint of ~rowth rate.展开更多
LHP1 mediates recruitment of the PRC2 histone methyltransferase complex to chromatin and thereby facilitates maintenance of H3K27me3 on FLC, a key flowering repressor gene. Here, we report that the PWWP domain protei...LHP1 mediates recruitment of the PRC2 histone methyltransferase complex to chromatin and thereby facilitates maintenance of H3K27me3 on FLC, a key flowering repressor gene. Here, we report that the PWWP domain proteins （PDPs） interact with FVE and MSI5 to suppress FLC expression and thereby promote flowering. We demonstrated that FVE, MSI5, and PDP3 were co-purified with LHP1. The H3K27me3 level on FLC was decreased in the pdp mutants as welt as in the fve/ msi5 double mutant. This study suggests that PDPs function together with FVE and MSI5 to regulate the function of the PRC2 complex on FLC.展开更多
Background： Tumor necrosis factor-α （TNF-α） plays an important role in progressive contractile dysfunction in several cardiac diseases. The cytotoxic effects of TNF-α are suggested to be partly mediated by react...Background： Tumor necrosis factor-α （TNF-α） plays an important role in progressive contractile dysfunction in several cardiac diseases. The cytotoxic effects of TNF-α are suggested to be partly mediated by reactive oxygen species （ROS）- and mitochondria-dependent apoptosis. Glucagon-like peptide- 1 （GLP-1） or its analogue exhibits protective effects on the cardiovascular system. The objective of the study was to assess the effects ofexenatide, a GLP- 1 analogue, on oxidative stress, and apoptosis in TNF-α-treated cardiomyocytes in vitro. Methods： Isolated neonatal rat cardiomyocytes were divided into three groups： Control group, with cells cultured in normal conditions without intervention; TNF-α group, with cells incubated with TNF-α （40 ng/ml） for 6, 12, or 24 h without pretreatment with exenatide; and exenatide group, with cells pretreated with exenatide （100 nmol/L） 30 mins before TNF-α （40 ng/ml） stimulation. We evaluated apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL） assay and flow cytometry, measured ROS production and mitochondrial membrane potential （MMP） by specific the fluorescent probes, and assessed the levels of proteins by Western blotting for all the groups. Results： Exenatide pretreatment significantly reduced cardiomyocyte apoptosis as measured by flow cytometry and TUNEL assay at 12 h and 24 h. Also, exenatide inhibited excessive ROS production and maintained MMP. Furthermore, declined cytochrome-c release and cleaved caspase-3 expression and increased bcl-2 expression with concomitantly decreased Bax activation were observed in exenatide-pretreated cultures. Conclusion： These results suggested that exenatide exerts a protective effect on cardiomyocytes, preventing TNF-α-induced apoptosis; the anti-apoptotic effects may be associated with protection ofmitochondrial function.展开更多
Objective:To explore the anti-inflammatory effects of ethyl lithospermate in lipopolysaccharide(LPS)-stimulated RAW 264.7 murine-derived macrophages and zebrafish,and its underlying mechanisms.Methods:3-[4,5-dimethylt...Objective:To explore the anti-inflammatory effects of ethyl lithospermate in lipopolysaccharide(LPS)-stimulated RAW 264.7 murine-derived macrophages and zebrafish,and its underlying mechanisms.Methods:3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide(MTT)assays were performed to investigate the toxicity of ethyl lithospermate at different concentrations(12.5–100μmol/L)in RAW 264.7 cells.The cells were stimulated with LPS(100 ng/mL)for 12 h to establish an inflammation model in vitro,the production of proinflammatory cytokines interleukin(IL)-6 and tumor necrosis factorα(TNF-α)were assessed by enzyme linked immunosorbent assay(ELISA).Western blot was used to ascertain the protein expressions of signal transducer and activator of transcription 3(STAT3),nuclear factor kappa B(NF-κB)p65,phospho-STAT3(p-STAT3,Tyr705),inhibitor of NF-κB(IκB)α,and phospho-IκBα(p-IκBα,Ser32),and confocal imaging was used to identify the nuclear translocation of NF-κB p65 and p-STAT3(Tyr705).Additionally,the yolk sacs of zebrafish(3 days post fertilization)were injected with 2 nL LPS(0.5 mg/mL)to induce an inflammation model in vivo.Survival analysis,hematoxylin-eosin(HE)staining,observation of neutrophil migration,and quantitative real-time polymerase chain reaction(qR T-PCR)were used to further study the anti-inflammatory effects of ethyl lithospermate and its probable mechanisms in vivo.Results:The non-toxic concentrations of ethyl lithospermate have been found to range from 12.5 to 100μmol/L.Ethyl lithospermate inhibited the release of IL-6 and TNF-α(P<0.05 or P<0.01),decreased IκBαdegradation and phosphorylation(P<0.05)as well as the nuclear translocation of NF-κB p65 and p-STAT3(Tyr705)in LPS-induced RAW 264.7 cells(P<0.01).Ethyl lithospermate also decreased inflammatory cells infiltration and neutrophil migration while increasing the survival rate of LPS-stimulated zebrafish(P<0.05 or P<0.01).In addition,ethyl lithospermate also inhibited the mR NA expression levels of of IL-6,TNF-α,IκBα,STAT3,and NF展开更多
Background Detection of coronary microembolization is of clinical importance for patient management and prediction of long-term outcome. However, there are few studies of the changes of magnetic resonance imaging afte...Background Detection of coronary microembolization is of clinical importance for patient management and prediction of long-term outcome. However, there are few studies of the changes of magnetic resonance imaging after coronary microembolization. This study was designed to investigate the imaging of the left ventricle using delayed contrast enhanced magnetic resonance imaging as well as the left ventricular ejection fraction after coronary microembolization in animal models.Methods Eight miniswine, of either sex （body weight 21-25 kg）, were used to make the coronary microembolization model. After coronary angiography, a 2.8F infusion catheter was placed in the left anterior descending artery with the tip located between the second and third diagonal branches. Microspheres with the diameter of 42μm and mean dosage of 1.2×10^5 were selectively infused into the left anterior descending artery. First pass and stressed first pass perfusion scan were performed after cine images were acquired. Then a second bolus of 0.15 mmol/kg gadolinium DTPA was given at a rate of 2 ml/s. Ten minutes later, delayed contrast enhanced magnetic resonance images of the left ventricular wall were evaluated. Serum changes of tumor necrosis factor a （TNF-α） were evaluated by enzyme-linked immunosorbent assay （ELISA）.Results Hypoenhancement was not observed at first pass perfusion at the anterior wall of the left ventricle. Hyperenhancements of the anterior-septal and anterior wall of the left ventricle was in evidence on delayed enhancement images 6 hours after microembolization and disappeared one week later. The characteristic change of coronary microembolization on delayed contrast enhanced magnetic imaging was non-enhanced regions within the hyperenhancement zone. Left ventricular ejection fraction measured by magnetic resonance imaging decreased significantly from 0.451±0.063 at baseline to 0.362±0.070 at the sixth hour （P 〈0.01）, and recovered to 0.431±0.053 one week later （P 〈0.01 vs 6th hour）. Compared 展开更多
This paper presents an analytical investigation of elastic collapse of asymmetrically corroded rings under external pressure when both internal corrosion and external corrosion exist.Governing equations are derived fo...This paper presents an analytical investigation of elastic collapse of asymmetrically corroded rings under external pressure when both internal corrosion and external corrosion exist.Governing equations are derived for membrane inextensible and membrane extensible cases;a full continuity condition is rigorously derived by the Euler-Bernoulli beam assumption.Comparison with finite element analysis(FEA)shows good agreement for load-displacement curves but membrane extensibility should be included to accurately predict the initial deformation phase,although the discrepancy for both the inextensible and extensible models vanishes for larger deformation phases.By the perturbation technique,the initial load-displacement slope is calculated,and extensive parametric analysis shows complicated dependency of this slope on the misalignment parameter and the angular extent of corrosion.We also present an infallible semi-analytical perturbation solution for both homogeneous and inhomogeneous cases by the Lyapunov arbitrary small-parameter method and show that the resulting power series always converges;then a mathematical argument of analyticity has been presented to illustrate that the so-called homotopy analysis method in the literature converges when the convergence controlling parameter is lying in(-2,0).This paper serves to enhance the understanding of asymmetrically corroded rings and it is mainly relevant to offshore engineering.展开更多
A precipitation-hardening high-entropy alloy(HEA),(FeCoNi)_(86)Al_(7) Ti_(7),was successfully fabricated using selective laser melting(SLM).Severe segregation of Ti occurred at the boundaries of dislocation cells.Ther...A precipitation-hardening high-entropy alloy(HEA),(FeCoNi)_(86)Al_(7) Ti_(7),was successfully fabricated using selective laser melting(SLM).Severe segregation of Ti occurred at the boundaries of dislocation cells.Therefore,homogenization heat treatment at 1150℃for 0.5 h was performed to alleviate the microsegregation.After homogenization,almost no dislocation cells were left in the grains,and recrystallization occurred as the average grain size increased from 37 to 54μm.Compared with the initial as-built HEA,the ductility of the HEA increases significantly from 29%to 40%,and the strength decreases slightly from 710 to 606 MPa.For further aging,pre-homogenization can decrease the precipitation of ordered L2_(1) phases.Because void has a high propensity to initiate from the matrix/L2_(1) incoherent interface,pre-homogenization reduced the number of weak points,thus considerably improving the plastic deformation ability of the aged HEA by 36%.In addition,the strengthening mechanism has also been analyzed for the aged HEA.It was revealed that the coherent L1_(2)precipitate contributed the most to the increased strength.展开更多
This paper concerns the problem of output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, and proposes a novel saturated OFT controller based on fuzzy self-tuning proportional and der...This paper concerns the problem of output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, and proposes a novel saturated OFT controller based on fuzzy self-tuning proportional and derivative (PD) gains. First, aiming to accomplish the whole closed-loop control with only position measurements, a linear filter is involved to generate a pseudo velocity error signal. Second, different from previous strategies, the arctangent function with error-gain is applied to ensure the boundedness of the torque control input, and an explicit system stability proof is made by using the theory of singularly perturbed systems. Moreover, a fuzzy self-tuning PD regulator, which guarantees the continuous stability of the overall closed-loop system, is added to obtain an adaptive performance in tackling the disturbances during tracking control. Simulation showed that the proposed controller gains more satisfactory tracking results than the others, with a better dynamic response performance and stronger anti-disturbance capability.展开更多
A new one-dimensional polymer, [Zn（SC6H4S）（1,3-DPA）]n （1, SC6H4S = 1,4-ben- zenedithiolate and 1,3-DPA = 1,3-diaminepropane）, has been synthesized and characterized by elemental analysis, PXRD, IR spectra, and s...A new one-dimensional polymer, [Zn（SC6H4S）（1,3-DPA）]n （1, SC6H4S = 1,4-ben- zenedithiolate and 1,3-DPA = 1,3-diaminepropane）, has been synthesized and characterized by elemental analysis, PXRD, IR spectra, and single-crystal X-ray diffraction. The complex crystallizes in triclinic system, space group P1, with a = 6.7119（1）, b = 9.0230（2）, c = 10.4943（2） A, a = 69.288（1）, β = 75.848（1）, ）, = 81.513（1）°, V= 575.123（19） A3, Dc = 1.615 g/cm^3, Z = 2, F（000） = 288; the final S = 1.070, R = 0.0234, and wR = 0.0551. The compound consists of an infinite zigzag chain formed by [Zn（1,3-DPA）]^2＋ units joined by SC6H4S ligands. Each chain interacts with neighboring chains via weak N-H…S hydrogen bonds to form an extended three-dimensional （3D） supramolecular network. The thermal and photoluminescent properties of 1 have also been investigated.展开更多
Under the new situation of the coordination of rural and urban development,the employment and transfer of surplus labor force have become the major social problems in China.Based on the field investigation on Xiyu Vil...Under the new situation of the coordination of rural and urban development,the employment and transfer of surplus labor force have become the major social problems in China.Based on the field investigation on Xiyu Village of Gexianshan Town in Pengzhou City,the surplus labor force and the absorptive capacity of non-agricultural industries are estimated by using per capita cultivated method and output value absorption method.Based on this,the transfer pattern of surplus labor force is generalized and the corresponding suggestions for transfer are put forward.展开更多
Background： Coronary microembolization （CME） has been frequently seen in acute coronary syndromes and percutaneous coronary intervention. Small animal models are required for further studies of CME related to sever...Background： Coronary microembolization （CME） has been frequently seen in acute coronary syndromes and percutaneous coronary intervention. Small animal models are required for further studies of CME related to severe prognosis. This study aimed to explore a new mouse model of CME. Methods： The mouse model of CME was established by injecting polystyrene microspheres into the left ventricular chamber during 15-s occlusion of the ascending aorta. Based on the average diameter and dosage used, 30 C57BL/6 male mice were randomly divided into five groups （n = 6 in each）： 9 μm/500,000, 9 μm/800,000, 17 μm/200,000, 17 μm/500,000, and sham groups. The postoperative survival and performance of the mice were recorded. The mice were sacrificed 3 or 10 days after the surgery. The heart tissues were harvested for hematoxylin and eosin staining and Masson trichrome staining to compare the extent of inflammatory cellular infiltration and fibrin deposition among groups and for scanning transmission electron microscopic examinations to see the ultrastructural changes after CME. Results： Survival analysis demonstrated that the cumulative survival rate of the 17 μm/500,000 group was significantly lower than that of the sham group （0/6 vs. 6/6, P = 0.001）. The cumulative survival rate of the 17 μm/200,000 group was lower than those of the sham and 9 μm groups with no statistical difference （cumulative survival rate of the 17 μm/200,000, 9 μm/800,000, 9 μm/500,000, and sham groups was 4/6, 5/6, 6/6, and 6/6, respectively）. The pathological alterations were similar between the 9 μm/500,000 and 9 μm/800,000 groups. The extent of inflammatory cellular infiltration and fibrin deposition was more severe in the 17 μm/200,000 group than in the 9 μm/500,000 and 9 μm/800,000 groups 3 and 10 days after the surgery. Scanning transmission electron microscopic examinations revealed platelet aggregation and adhesion, microthrombi formation, and changes in cardiomyocytes. Conclusion： The injection of 500,000 p展开更多
基金Project supported by the National Basic Research Program (973) of China (No. 2003CB415003)the Pilot Project of Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX3-SW-443)the National Natural Science Foundation of China (No. 40473055).
文摘An investigation of gaseous elemental mercury concentration in atmosphere was conducted at Beijing and Guangzhou urban, Yangtze Delta regional sites and China Global Atmosphere Watch Baseline Observatory （CGAWBO） in Mt. Waliguan of remote continental area of China. High temporal resolved data were obtained using automated mercury analyzer RA-915^＋. Results showed that the overall hourly mean Hg^0 concentrations in Mt. Waliguan were 1.7±1.1 ng/m3 in summer and 0.6±0.08 ng/m^3 in winter. The concentration in Yangtze Delta regional site was 5.4±4.1 ng/m^3, which was much higher than those in Waliguan continental background area and also higher than that found in North America and Europe rural areas. In Beijing urban area the overall hourly mean Hg^0 concentrations were 8.3±3.6 ng/m^3 in winter, 6.5±5.2 ng/m^3 in spring, 4.9±3.3 ng/m^3 in summer, and 6.7±3.5 ng/m^3 in autumn, respectively, and the concentration was 13.5±7.1 ng/m^3 in Guangzhou site. The mean concentration reached the lowest value at 14：00 and the highest at 02：00 or 20：00 in all monitoring campaigns in Beijing and Guangzhou urban areas, which contrasted with the results measured in Yangtze Delta regional site and Mr. Waliguan. The features of concentration and diurnal variation of Hg^0 in Beijing and Guangzhou implied the importance of local anthropogenic sources in contributing to the high Hg^0 concentration in urban areas of China. Contrary seasonal variation patterns of Hg^0 concentration were found between urban and remote sites. In Beijing the highest Hg^0 concentration was in winter and the lowest in summer, while in Mt. Waliguan the Hg^0 concentration in summer was higher than that in winter. These indicated that different processes and factors controlled Hg^0 concentration in urban, regional and remote areas.
基金financially supported by the National Natural Science Foundation of China(No.51274154)the National High-Tech Research and Development Program of China(No.2012AA03A504)+1 种基金the State Key Laboratory of Development and Application Technology of Automotive Steels(Baosteel Group)the Key Project of Hubei Education Committee,China(No.20121101)
文摘The growth rates of bainite plates in an Fe-C-Mn-Si superbainitie steel were investigated by in situ observation. The lengthening rates of ferrite bainite during both cooling and isothermal holding processes were observed and the growth rates of bainite plates nucleating at grain boundaries, within grains and on preformed bainite were measured. It is indicated that the lengthening rates of bainite plates during the cooling and isothermal processes were different, and that the growth rates of bainite plates nucleating at different types of sites also demon- strated diversity. The bainite plates initiating at [vain boundaries during cooling grew the fastest, while the plates nucleating on preformed bainite did the slowest. However, the growth rate of the bainite plates nucleating at grain boundaries during isothermal transformation de- creased the most, whereas the bainite plates initiating within grains grew the fastest. In addition, the growth rate of ferrite bainite in the study supported the diffusion transformation mechanism of bainite from the viewooint of ~rowth rate.
基金supported by the National Key Research and Development Program of China (2016YFA0500801)the 973 Program (2011CB812600) from the Chinese Ministry of Science and Technology (to X.J.H.)the National Natural Science Foundation of China (31370317 and 31571584 to B.W.)
文摘LHP1 mediates recruitment of the PRC2 histone methyltransferase complex to chromatin and thereby facilitates maintenance of H3K27me3 on FLC, a key flowering repressor gene. Here, we report that the PWWP domain proteins （PDPs） interact with FVE and MSI5 to suppress FLC expression and thereby promote flowering. We demonstrated that FVE, MSI5, and PDP3 were co-purified with LHP1. The H3K27me3 level on FLC was decreased in the pdp mutants as welt as in the fve/ msi5 double mutant. This study suggests that PDPs function together with FVE and MSI5 to regulate the function of the PRC2 complex on FLC.
基金Financial support and sponsorship This work was supported by grants from the National Natural Science Foundation of China （No. 81200146 and 81370322）, New Teacher Foundation of Ministry of Education （No. 20120071120061） and Grant of Shanghai Municipal Commission of Health and Family Planning （No. XBR2013071）.
文摘Background： Tumor necrosis factor-α （TNF-α） plays an important role in progressive contractile dysfunction in several cardiac diseases. The cytotoxic effects of TNF-α are suggested to be partly mediated by reactive oxygen species （ROS）- and mitochondria-dependent apoptosis. Glucagon-like peptide- 1 （GLP-1） or its analogue exhibits protective effects on the cardiovascular system. The objective of the study was to assess the effects ofexenatide, a GLP- 1 analogue, on oxidative stress, and apoptosis in TNF-α-treated cardiomyocytes in vitro. Methods： Isolated neonatal rat cardiomyocytes were divided into three groups： Control group, with cells cultured in normal conditions without intervention; TNF-α group, with cells incubated with TNF-α （40 ng/ml） for 6, 12, or 24 h without pretreatment with exenatide; and exenatide group, with cells pretreated with exenatide （100 nmol/L） 30 mins before TNF-α （40 ng/ml） stimulation. We evaluated apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL） assay and flow cytometry, measured ROS production and mitochondrial membrane potential （MMP） by specific the fluorescent probes, and assessed the levels of proteins by Western blotting for all the groups. Results： Exenatide pretreatment significantly reduced cardiomyocyte apoptosis as measured by flow cytometry and TUNEL assay at 12 h and 24 h. Also, exenatide inhibited excessive ROS production and maintained MMP. Furthermore, declined cytochrome-c release and cleaved caspase-3 expression and increased bcl-2 expression with concomitantly decreased Bax activation were observed in exenatide-pretreated cultures. Conclusion： These results suggested that exenatide exerts a protective effect on cardiomyocytes, preventing TNF-α-induced apoptosis; the anti-apoptotic effects may be associated with protection ofmitochondrial function.
基金Supported by Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (No.GDHVPS2018)Young Elite Scientists Sponsorship Program by the China Association of Chinese Medicine (No.2019-QNRC2-C14)。
文摘Objective:To explore the anti-inflammatory effects of ethyl lithospermate in lipopolysaccharide(LPS)-stimulated RAW 264.7 murine-derived macrophages and zebrafish,and its underlying mechanisms.Methods:3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide(MTT)assays were performed to investigate the toxicity of ethyl lithospermate at different concentrations(12.5–100μmol/L)in RAW 264.7 cells.The cells were stimulated with LPS(100 ng/mL)for 12 h to establish an inflammation model in vitro,the production of proinflammatory cytokines interleukin(IL)-6 and tumor necrosis factorα(TNF-α)were assessed by enzyme linked immunosorbent assay(ELISA).Western blot was used to ascertain the protein expressions of signal transducer and activator of transcription 3(STAT3),nuclear factor kappa B(NF-κB)p65,phospho-STAT3(p-STAT3,Tyr705),inhibitor of NF-κB(IκB)α,and phospho-IκBα(p-IκBα,Ser32),and confocal imaging was used to identify the nuclear translocation of NF-κB p65 and p-STAT3(Tyr705).Additionally,the yolk sacs of zebrafish(3 days post fertilization)were injected with 2 nL LPS(0.5 mg/mL)to induce an inflammation model in vivo.Survival analysis,hematoxylin-eosin(HE)staining,observation of neutrophil migration,and quantitative real-time polymerase chain reaction(qR T-PCR)were used to further study the anti-inflammatory effects of ethyl lithospermate and its probable mechanisms in vivo.Results:The non-toxic concentrations of ethyl lithospermate have been found to range from 12.5 to 100μmol/L.Ethyl lithospermate inhibited the release of IL-6 and TNF-α(P<0.05 or P<0.01),decreased IκBαdegradation and phosphorylation(P<0.05)as well as the nuclear translocation of NF-κB p65 and p-STAT3(Tyr705)in LPS-induced RAW 264.7 cells(P<0.01).Ethyl lithospermate also decreased inflammatory cells infiltration and neutrophil migration while increasing the survival rate of LPS-stimulated zebrafish(P<0.05 or P<0.01).In addition,ethyl lithospermate also inhibited the mR NA expression levels of of IL-6,TNF-α,IκBα,STAT3,and NF
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 30671998）.
文摘Background Detection of coronary microembolization is of clinical importance for patient management and prediction of long-term outcome. However, there are few studies of the changes of magnetic resonance imaging after coronary microembolization. This study was designed to investigate the imaging of the left ventricle using delayed contrast enhanced magnetic resonance imaging as well as the left ventricular ejection fraction after coronary microembolization in animal models.Methods Eight miniswine, of either sex （body weight 21-25 kg）, were used to make the coronary microembolization model. After coronary angiography, a 2.8F infusion catheter was placed in the left anterior descending artery with the tip located between the second and third diagonal branches. Microspheres with the diameter of 42μm and mean dosage of 1.2×10^5 were selectively infused into the left anterior descending artery. First pass and stressed first pass perfusion scan were performed after cine images were acquired. Then a second bolus of 0.15 mmol/kg gadolinium DTPA was given at a rate of 2 ml/s. Ten minutes later, delayed contrast enhanced magnetic resonance images of the left ventricular wall were evaluated. Serum changes of tumor necrosis factor a （TNF-α） were evaluated by enzyme-linked immunosorbent assay （ELISA）.Results Hypoenhancement was not observed at first pass perfusion at the anterior wall of the left ventricle. Hyperenhancements of the anterior-septal and anterior wall of the left ventricle was in evidence on delayed enhancement images 6 hours after microembolization and disappeared one week later. The characteristic change of coronary microembolization on delayed contrast enhanced magnetic imaging was non-enhanced regions within the hyperenhancement zone. Left ventricular ejection fraction measured by magnetic resonance imaging decreased significantly from 0.451±0.063 at baseline to 0.362±0.070 at the sixth hour （P 〈0.01）, and recovered to 0.431±0.053 one week later （P 〈0.01 vs 6th hour）. Compared
基金supported by the Natural Science Foundation of Zhejiang Province(No.LQ21E050001)the Science and Technology Plan Project of Zhejiang Bureau of Quality and Technical Supervision(No.20200307)Eyas Program Incubation Project of Zhejiang Provincial Administration for Market Regulation(No.CY2022221)China。
文摘This paper presents an analytical investigation of elastic collapse of asymmetrically corroded rings under external pressure when both internal corrosion and external corrosion exist.Governing equations are derived for membrane inextensible and membrane extensible cases;a full continuity condition is rigorously derived by the Euler-Bernoulli beam assumption.Comparison with finite element analysis(FEA)shows good agreement for load-displacement curves but membrane extensibility should be included to accurately predict the initial deformation phase,although the discrepancy for both the inextensible and extensible models vanishes for larger deformation phases.By the perturbation technique,the initial load-displacement slope is calculated,and extensive parametric analysis shows complicated dependency of this slope on the misalignment parameter and the angular extent of corrosion.We also present an infallible semi-analytical perturbation solution for both homogeneous and inhomogeneous cases by the Lyapunov arbitrary small-parameter method and show that the resulting power series always converges;then a mathematical argument of analyticity has been presented to illustrate that the so-called homotopy analysis method in the literature converges when the convergence controlling parameter is lying in(-2,0).This paper serves to enhance the understanding of asymmetrically corroded rings and it is mainly relevant to offshore engineering.
基金financially supported by the National Natural Science Foundation of China (No.51971149)the Science and Technology Innovation Commission of Shenzhen (No.KQJSCX20180328095612712)
文摘A precipitation-hardening high-entropy alloy(HEA),(FeCoNi)_(86)Al_(7) Ti_(7),was successfully fabricated using selective laser melting(SLM).Severe segregation of Ti occurred at the boundaries of dislocation cells.Therefore,homogenization heat treatment at 1150℃for 0.5 h was performed to alleviate the microsegregation.After homogenization,almost no dislocation cells were left in the grains,and recrystallization occurred as the average grain size increased from 37 to 54μm.Compared with the initial as-built HEA,the ductility of the HEA increases significantly from 29%to 40%,and the strength decreases slightly from 710 to 606 MPa.For further aging,pre-homogenization can decrease the precipitation of ordered L2_(1) phases.Because void has a high propensity to initiate from the matrix/L2_(1) incoherent interface,pre-homogenization reduced the number of weak points,thus considerably improving the plastic deformation ability of the aged HEA by 36%.In addition,the strengthening mechanism has also been analyzed for the aged HEA.It was revealed that the coherent L1_(2)precipitate contributed the most to the increased strength.
基金Project (No. 2008C21106) supported by the Science and Technology Foundation of Zhejiang Province, China
文摘This paper concerns the problem of output feedback tracking (OFT) control with bounded torque inputs of robot manipulators, and proposes a novel saturated OFT controller based on fuzzy self-tuning proportional and derivative (PD) gains. First, aiming to accomplish the whole closed-loop control with only position measurements, a linear filter is involved to generate a pseudo velocity error signal. Second, different from previous strategies, the arctangent function with error-gain is applied to ensure the boundedness of the torque control input, and an explicit system stability proof is made by using the theory of singularly perturbed systems. Moreover, a fuzzy self-tuning PD regulator, which guarantees the continuous stability of the overall closed-loop system, is added to obtain an adaptive performance in tackling the disturbances during tracking control. Simulation showed that the proposed controller gains more satisfactory tracking results than the others, with a better dynamic response performance and stronger anti-disturbance capability.
基金Supported by the National Natural Science Foundation of China(No.21301035)
文摘A new one-dimensional polymer, [Zn（SC6H4S）（1,3-DPA）]n （1, SC6H4S = 1,4-ben- zenedithiolate and 1,3-DPA = 1,3-diaminepropane）, has been synthesized and characterized by elemental analysis, PXRD, IR spectra, and single-crystal X-ray diffraction. The complex crystallizes in triclinic system, space group P1, with a = 6.7119（1）, b = 9.0230（2）, c = 10.4943（2） A, a = 69.288（1）, β = 75.848（1）, ）, = 81.513（1）°, V= 575.123（19） A3, Dc = 1.615 g/cm^3, Z = 2, F（000） = 288; the final S = 1.070, R = 0.0234, and wR = 0.0551. The compound consists of an infinite zigzag chain formed by [Zn（1,3-DPA）]^2＋ units joined by SC6H4S ligands. Each chain interacts with neighboring chains via weak N-H…S hydrogen bonds to form an extended three-dimensional （3D） supramolecular network. The thermal and photoluminescent properties of 1 have also been investigated.
文摘Under the new situation of the coordination of rural and urban development,the employment and transfer of surplus labor force have become the major social problems in China.Based on the field investigation on Xiyu Village of Gexianshan Town in Pengzhou City,the surplus labor force and the absorptive capacity of non-agricultural industries are estimated by using per capita cultivated method and output value absorption method.Based on this,the transfer pattern of surplus labor force is generalized and the corresponding suggestions for transfer are put forward.
文摘Background： Coronary microembolization （CME） has been frequently seen in acute coronary syndromes and percutaneous coronary intervention. Small animal models are required for further studies of CME related to severe prognosis. This study aimed to explore a new mouse model of CME. Methods： The mouse model of CME was established by injecting polystyrene microspheres into the left ventricular chamber during 15-s occlusion of the ascending aorta. Based on the average diameter and dosage used, 30 C57BL/6 male mice were randomly divided into five groups （n = 6 in each）： 9 μm/500,000, 9 μm/800,000, 17 μm/200,000, 17 μm/500,000, and sham groups. The postoperative survival and performance of the mice were recorded. The mice were sacrificed 3 or 10 days after the surgery. The heart tissues were harvested for hematoxylin and eosin staining and Masson trichrome staining to compare the extent of inflammatory cellular infiltration and fibrin deposition among groups and for scanning transmission electron microscopic examinations to see the ultrastructural changes after CME. Results： Survival analysis demonstrated that the cumulative survival rate of the 17 μm/500,000 group was significantly lower than that of the sham group （0/6 vs. 6/6, P = 0.001）. The cumulative survival rate of the 17 μm/200,000 group was lower than those of the sham and 9 μm groups with no statistical difference （cumulative survival rate of the 17 μm/200,000, 9 μm/800,000, 9 μm/500,000, and sham groups was 4/6, 5/6, 6/6, and 6/6, respectively）. The pathological alterations were similar between the 9 μm/500,000 and 9 μm/800,000 groups. The extent of inflammatory cellular infiltration and fibrin deposition was more severe in the 17 μm/200,000 group than in the 9 μm/500,000 and 9 μm/800,000 groups 3 and 10 days after the surgery. Scanning transmission electron microscopic examinations revealed platelet aggregation and adhesion, microthrombi formation, and changes in cardiomyocytes. Conclusion： The injection of 500,000 p
