AIthough atherosclerosis has been considered to be multi-factorial disease in which genetic,environmental, metabolic factors have been implicated, the gaps remain in our knowledge of the etiopathogenesis of atheroscle...AIthough atherosclerosis has been considered to be multi-factorial disease in which genetic,environmental, metabolic factors have been implicated, the gaps remain in our knowledge of the etiopathogenesis of atherosclerosis. There is mounting evidence that inflammation plays an important role in the initiation, development as well as evolution of atherosclerosis, suggesting that atherosclerosis is an inflammation disease. Although triggers and pathways of inflammation are probably multiple and different in different clinical settings, the data from animals as well as humans including our groups indicated that an inflammatory process was involved in all stages of atherosclerosis appeared in different clinical entities.展开更多
The fermented Chinese formula Shuan-Tong-Ling is composed of radix puerariae（Gegen）,salvia miltiorrhiza（Danshen）,radix curcuma（Jianghuang）,hawthorn（Shanzha）,salvia chinensis（Shijianchuan）,sinapis alba（Baiji...The fermented Chinese formula Shuan-Tong-Ling is composed of radix puerariae（Gegen）,salvia miltiorrhiza（Danshen）,radix curcuma（Jianghuang）,hawthorn（Shanzha）,salvia chinensis（Shijianchuan）,sinapis alba（Baijiezi）,astragalus（Huangqi）,panax japonicas（Zhujieshen）,atractylodes macrocephala koidz（Baizhu）,radix paeoniae alba（Baishao）,bupleurum（Chaihu）,chrysanthemum（Juhua）,rhizoma cyperi（Xiangfu） and gastrodin（Tianma）,whose aqueous extract was fermented with lactobacillus,bacillus aceticus and saccharomycetes.ShuanTong-Ling is a formula used to treat brain diseases including ischemic stroke,migraine,and vascular dementia.Shuan-Tong-Ling attenuated H_2O_2-induced oxidative stress in rat microvascular endothelial cells.However,the potential mechanism involved in these effects is poorly understood.Rats were intragastrically treated with 5.7 or 17.2 m L/kg Shuan-Tong-Ling for 7 days before middle cerebral artery occlusion was induced.The results indicated Shuan-Tong-Ling had a cerebral protective effect by reducing infarct volume and increasing neurological scores.Shuan-Tong-Ling also decreased tumor necrosis factor-α and interleukin-1β levels in the hippocampus on the ischemic side.In addition,Shuan-Tong-Ling upregulated the expression of SIRT1 and Bcl-2 and downregulated the expression of acetylated-protein 53 and Bax.Injection of 5 mg/kg silent information regulator 1（SIRT1） inhibitor EX527 into the subarachnoid space once every 2 days,four times,reversed the above changes.These results demonstrate that Shuan-Tong-Ling might benefit cerebral ischemia/reperfusion injury by reducing inflammation and apoptosis through activation of the SIRT1 signaling pathway.展开更多
Proper meshing of Hy-Vo silent chain and sprocket is important for realizing the transmission of the silent chain with more efficiency and less noise. Based on the study of the meshing theory of the Hy-Vo silent chain...Proper meshing of Hy-Vo silent chain and sprocket is important for realizing the transmission of the silent chain with more efficiency and less noise. Based on the study of the meshing theory of the Hy-Vo silent chain with the sprocket and the roll cutting machining principle of the sprocket with the hob, the proper conditions of the meshing for the Hy-Vo silent chain and the sprocket are put forward with the variable pitch characteristic of the Hy-Vo silent chain taken into consideration, and the proper meshing design method on the condition that the value of the link tooth pressure angle is unequal to the value of the sprocket tooth pressure angle is studied. Experiments show that this new design method is feasible. In addition, the design of the pitch, the sprocket tooth pressure angle and the fillet radius of the sprocket addendum circle are studied. It is crucial for guiding the design of the hob which cuts the Hy-Vo silent chain sprocket.展开更多
Based on the study of the meshing theory of a new silent chain and sprockets, and the rolling cutting theory of sprocket and hob, the harmonious relations of dominating dimensions among the new silent chain, sprocket ...Based on the study of the meshing theory of a new silent chain and sprockets, and the rolling cutting theory of sprocket and hob, the harmonious relations of dominating dimensions among the new silent chain, sprocket and hob is build, the meshing conditions are expatiated, and the resolved expression, which can instruct design and calculation, is educed. The tests show that the meshing design method is feasible.展开更多
Many species of owls are able to fly noiselessly, and their wing feathers play an important role for the silent flight. In this paper, we studied the sound suppression mechanism of the eagle owl （Bubo bubo） by Stere...Many species of owls are able to fly noiselessly, and their wing feathers play an important role for the silent flight. In this paper, we studied the sound suppression mechanism of the eagle owl （Bubo bubo） by Stereo Microscope （SM）, Scanning Electron Microscopy （SEM） and Laser Scanning Confocal Microscope （LSCM）. To investigate the effects of special charac- teristics of wing feather on owl silent flight, the acoustic properties, including the sound absorption coefficient and flight noise, were compared between the eagle owl and common buzzard （Buteo buteo）. The results show that the eagle owl generates lower noise than common buzzard during flight, and its wing feather has better sound absorption properties. The leading edge serration and trailing edge fringe can improve the pressure fluctuation of turbulence boundary, and suppress the generation of vortex sound. The elongated distal barbules form a multi-layer grid porous structure which also has an effect on sound absorption. This research not only can give the inspiration for solving the aerodynamic noise of aircraft and engineering machine, but also can provide a new idea for the design of low-noise devices.展开更多
Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and af...Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy.The mechanistic target of rapamycin（m TOR） is a promising agent for the development of novel regenerative strategies for the treatment of DM.m TOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis,insulin resistance,insulin secretion,stem cell proliferation and differentiation,pancreatic β-cell function,and programmed cell death with apoptosis and autophagy.m TOR is central element for the protein complexes m TOR Complex 1（m TORC1） and m TOR Complex 2（m TORC2） and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase（PI 3-K）,protein kinase B（Akt）,AMP activated protein kinase（AMPK）,silent mating type information regulation 2 homolog 1（Saccharomyces cerevisiae）（SIRT1）,Wnt1 inducible signaling pathway protein 1（WISP1）,and growth factors.As a result,m TOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease.Future studies directed to elucidate the delicate balance m TOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.展开更多
Objective： To explore the mechanism of the protective effects of Panax notoginseng saponins（PNS） on kidney in diabetic rats. Methods： Diabetic rat model was obtained by intravenous injection of alloxan, and the ra...Objective： To explore the mechanism of the protective effects of Panax notoginseng saponins（PNS） on kidney in diabetic rats. Methods： Diabetic rat model was obtained by intravenous injection of alloxan, and the rats were divided into model, PNS-100 mg/（kg·day） and PNS-200 mg/（kg·day） groups, 10 each. Another 10 rats injected with saline were served as control. Periodic acid-Schiff staining and immunological histological chemistry were used to observe histomorphology and tissue expression of bone morphogenetic protein-7（BMP-7）. Silent information regulator 1（SIRT1） was silenced in rat mesangial cells by RNA interference. The mR NA expressions of SIRT-1, monocyte chemoattractant protein-1（MCP-1）, transforming growth factor β1（TGF-β1） and plasminogen activator inhibitor-1（PAI-1） were analyzed by reverse transcription polymerase chain reaction. The protein expressions of SIRT1 and the acetylation of nuclear factor κB（NF-κB） P65 were determined by western blotting. The concentration of MCP-1, TGF-β1 and malondialdehyde（MDA） in culture supernatant were detected by enzyme-linked immuno sorbent assay. The activity of superoxide dismutase（SOD） was detected by the classical method of nitrogen and blue four. Results： In diabetic model rats, PNS could not only reduce blood glucose and lipid（P〈0.01）, but also increase protein level of BMP-7 and inhibit PAI-1 expression for suppressing fibrosis of the kidney. In rat mesangial cells, PNS could up-regulate the expression of SIRT1（P〈0.01） and in turn suppress the transcription of TGF-β1（P〈0.05） and MCP-1（P〈0.05）. PNS could also reverse the increased acetylation of NF-κB p65 by high glucose. In addition, redox regulation factor MDA was down-regulated（P〈0.05） and SOD was up-regulated（P〈0.01）, which were both induced by SIRT1 up-regulation. Conclusions： PNS could protect kidney from diabetes with the possible mechanism of up-regulating SIRT1, therefore inhibiting inflammation through dec展开更多
The prevalence of obesity and related conditions like non-alcoholic fatty liver disease(NAFLD) is increasing worldwide and therapeutic options are limited.Alternative treatment options are therefore intensively sought...The prevalence of obesity and related conditions like non-alcoholic fatty liver disease(NAFLD) is increasing worldwide and therapeutic options are limited.Alternative treatment options are therefore intensively sought after.An interesting candidate is the natural polyphenol resveratrol(RSV) that activates adenosinmonophosphate-activated protein kinase(AMPK) and silent information regulation-2 homolog 1(SIRT1).In addition,RSV has known anti-oxidant and anti-inflammatory effects.Here,we review the current evidence for RSVmediated effects on NAFLD and address the different aspects of NAFLD and non-alcoholic steatohepatitis(NASH) pathogenesis with respect to free fatty acid(FFA) flux from adipose tissue,hepatic de novo lipogenesis,inadequate FFA β-oxidation and additional intra- and extrahepatic inflammatory and oxidant hits.We review the in vivo evidence from animal studies and clinical trials.The abundance of animal studies reports a decrease in hepatic triglyceride accumulation,liver weight and a general improvement in histological fatty liver changes,along with a reduction in circulating insulin,glucose and lipid levels.Some studies document AMPK or SIRT1 activation,and modulation of relevant markers of hepatic lipogenesis,inflammation and oxidation status.However,AMPK/SIRT1-independent actions are also likely.Clinical trials are scarce and have primarily been performed with a focus on overweight/obese participants without a focus on NAFLD/NASH and histological liver changes.Future clinical studies with appropriate design are needed to clarify the true impact of RSV treatment in NAFLD/NASH patients.展开更多
OBJECTIVE To investigate icariside(ICS)Ⅱ protects against PC12 cel damage induced by oxygen-glucose deprivation and reoxygenation and explore its mechanism.METHODS The oxidative stress injury model was induced by oxy...OBJECTIVE To investigate icariside(ICS)Ⅱ protects against PC12 cel damage induced by oxygen-glucose deprivation and reoxygenation and explore its mechanism.METHODS The oxidative stress injury model was induced by oxygen-glucose deprivation/reoxygenation(OGD/R) 2 h/24 h in PC12 cells.N-acetyl-lcysteine(NAC),a classical anti-oxidant,was used as positive control.Pharmacodynamic experimental study groups as follows:control,control+ICS Ⅱ50 μmol·L^(-1),OGD/R,OGD/R+ICSⅡ 12.5 μmol·L^(-1),OGD/R + ICS Ⅱ 25 μmol·L^(-1),OGD/R + ICS Ⅱ50 μmol·L^(-1),and OGD/R+NAC 100 μmol·L^(-1) groups.Cell viability and lactate dehydrogenase(LDH) leakage rate were measured by MTT assay and LDH ELISA kit,respectively.Moreover,reactive oxygen species(ROS) ELISA kit was used for detection of intracellular ROS generation,Mito-SOX fluorescence staining was used for detecting production of ROS in mitochondria and mitochondrial membrane potential(MMP)was detected by rhodamine 123 dye.In addition,PC12 cells apoptosis was detected by one-step TUNEL assay.Furthermore,the expressions of nuclear factor erythroid 2-related factors(Nrf2),Keap1,HO^(-1),NQO^(-1),silent information regulator 3(SIRT3),IDH2,Bax,Bcl-2 and caspase 3 were detected by Western blotting analysis.RESULTS The results of MTT and LDH assay showed that OGD/R reduced the cell viability and improved LDH release compared with the control or ICSⅡ 50 μmol·L^(-1) alone(P<0.01).Meanwhile,OGD/R not only increased intracellular and mitochondrial ROS generation,but also elevated the fluorescence intensity of TUNEL staining,at the same time,the MMP was declined when challenged by OGD/R.Furthermore,the Western blotting results showed that OGD/R induced the increase in the expression of cytoplasm-Nrf2,Keap1,Bax and cleaved-caspase 3 level,while the decrease in the expression of nucleus-Nrf2,HO^(-1),NQO^(-1),SIRT3,IDH2 and Bcl-2(P<0.05).However,ICS Ⅱ significantly increased the viability of PC12 cells and reduced LDH leakage(P<0.01).Notably,ICS Ⅱ also suppressed ROS generati展开更多
AIM： To detect the expression of miR-211 in age-related cataract tissue, explore the effects of miR-211 on lens epithelial cell proliferation and apoptosis, and identify its target gene.METHODS： This study used real...AIM： To detect the expression of miR-211 in age-related cataract tissue, explore the effects of miR-211 on lens epithelial cell proliferation and apoptosis, and identify its target gene.METHODS： This study used real-time quantitative polymerase chain reaction（RT-q PCR） to measure the expression of miR-211 and its predicted target gene [silent matingtype information regulation 2 homolog 1（SIRT1）] in 46 anterior lens capsules collected from age-related cataract patients. Human lens epithelial cell line（SRA01/04） cells were transfected with either miR-211 mimics, mimic controls, miR-211 inhibitors or inhibitor controls, 72 h after transfection, miR NA and protein expression of SIRT1 were measured using RT-qP CR and Western blotting; then cells were exposed to 200 μmol/L H2O2 for 1h, whereupon cell viability was measured by MTS assay, caspase-3 assay was performed. Dual luciferase reporter assay was performed to verify the relationship between miR-211 of SIRT1.RESULTS： Compared to the control group, expression of miR-211 was significantly increased（P〈0.001）, the miR NA and protein expression of SIRT1 were significantly decreased（P〈0.001） in the anterior lens capsules of patients with age-related cataracts. Relative to the control group, SIRT1 miR NA and protein levels in the miR-211 mimic group were significantly reduced, cell proliferation activity significantly decreased, and caspase-3 activity was significantly increased（P〈0.001）. In the miR-211 inhibitor group, SIRT1 miRNA and protein expression were significantly increased, cell proliferation activity significantly increased, and caspase-3 activity was significantly decreased（P〈0.001）. A dual luciferase reporter assay confirmed that SIRT1 is a direct target of miR-211.CONCLUSION： miR-211 is highly expressed in the anterior lens capsules of patients with age-related cataracts. By negatively regulating the expression of SIRT1, miR-211 promotes lens epithelial cell apoptosis and inhibits lens epithelial cell proliferatio展开更多
The development of sensitive assays to detect small amounts of hepatitis B virus(HBV) DNA has favored the identification of occult hepatitis B infection(OBI), a virological condition characterized by a low level of HB...The development of sensitive assays to detect small amounts of hepatitis B virus(HBV) DNA has favored the identification of occult hepatitis B infection(OBI), a virological condition characterized by a low level of HBV replication with detectable levels of HBV DNA in liver tissue but an absence of detectable surface antigen of HBV(HBs Ag) in serum. The gold standard to diagnose OBI is the detection of HBV DNA in the hepatocytes by highly sensitive and specific techniques, a diagnostic procedure requiring liver tissue to be tested and the use of non-standardized non-commercially available techniques. Consequently, in everyday clinical practice, the detection of anti-hepatitis B core antibody(antiHBc) in serum of HBs Ag-negative subjects is used as a surrogate marker to identify patients with OBI. In patients with chronic hepatitis C(CHC), OBI has been identified in nearly one-third of these cases. Considerable data suggest that OBI favors the increase of liver damage and the development of hepatocellular carcinoma(HCC) in patients with CHC. The data from other studies, however, indicate no influence of OBI on the natural history of CHC, particularly regarding the risk of developing HCC.展开更多
BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple b...BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rat展开更多
The global increase in lifespan noted not only in developed nations,but also in large developing countries parallels an observed increase in a significant number of noncommunicable diseases,most notable neurodegenerat...The global increase in lifespan noted not only in developed nations,but also in large developing countries parallels an observed increase in a significant number of noncommunicable diseases,most notable neurodegenerative disorders.Neurodegenerative disorders present a number of challenges for treatment options that do not resolve disease progression.Furthermore,it is believed by the year 2030,the services required to treat cognitive disorders in the United States alone will exceed$2 trillion annually.Mammalian forkhead transcription factors,silent mating type information regulation 2 homolog 1(Saccharomyces cerevisiae),the mechanistic target of rapamycin,and the pathways of autophagy and apoptosis offer exciting avenues to address these challenges by focusing upon core cellular mechanisms that may significantly impact nervous system disease.These pathways are intimately linked such as through cell signaling pathways involving protein kinase B and can foster,sometimes in conjunction with trophic factors,enhanced neuronal survival,reduction in toxic intracellular accumulations,and mitochondrial stability.Feedback mechanisms among these pathways also exist that can oversee reparative processes in the nervous system.However,mammalian forkhead transcription factors,silent mating type information regulation 2 homolog 1,mechanistic target of rapamycin,and autophagy can lead to cellular demise under some scenarios that may be dependent upon the precise cellular environment,warranting future studies to effectively translate these core pathways into successful clinical treatment strategies for neurodegenerative disorders.展开更多
Objective:To observe the changes of ischemic myocardial cells apoptosis in rats following intervention with Xuefu Zhuyu Oral Liquid(血府逐瘀口服液,XFZY),as well as changes of protein expression of silent information r...Objective:To observe the changes of ischemic myocardial cells apoptosis in rats following intervention with Xuefu Zhuyu Oral Liquid(血府逐瘀口服液,XFZY),as well as changes of protein expression of silent information regulator 1(SIRT1)and SIRT1 pathway-related genes.Methods:H9c2 rat myocardial cells were divided into 6 groups:control group,oxygen glucose deprivation(OGD)group,SIRT1 siRNA group,OGD+SIRT1 siRNA group,OGD+XFZY group,and OGD+SIRT1 siRNA+XFZY group.Quantitative fluorescent polymerase chain reaction(PCR)and Western blot were used to detect the concentration variations of SIRT1 and its pathway-related genes and corresponding protein expression after XFZY intervention and SIRT1 transfection.Results:Compared with the control group,the mRNA and protein expressions of SIRT1 were decreased obviously,while the mRNA and protein levels of P53,forkhead box protein O1(FoxO1),FoxO3,FoxO4 and nuclear factor kappa B(NF-κB)were increased in the OGD group,SIRT1 siRNA group,and OGD+SIRT1 siRNA group(P<0.01).Compared with the OGD group and OGD+SIRT1 siRNA group,the treatment of XFZY inhibited the decline in SIRT1 mRNA and protein expressions(P<0.01),and down-regulated the mRNA and protein levels of P53,FoxO1,FoxO3,FoxO4 and NF-κB,respectively(P<0.05 or P<0.01).Conclusion:XFZY could prevent myocardial cells apoptosis probably by increasing the mRNA and protein expressions of SIRT1 and inhibiting the mRNA and protein expressions of P53,NF-κB,FoxO1,FoxO3 and FoxO4.展开更多
文摘AIthough atherosclerosis has been considered to be multi-factorial disease in which genetic,environmental, metabolic factors have been implicated, the gaps remain in our knowledge of the etiopathogenesis of atherosclerosis. There is mounting evidence that inflammation plays an important role in the initiation, development as well as evolution of atherosclerosis, suggesting that atherosclerosis is an inflammation disease. Although triggers and pathways of inflammation are probably multiple and different in different clinical settings, the data from animals as well as humans including our groups indicated that an inflammatory process was involved in all stages of atherosclerosis appeared in different clinical entities.
基金supported by the National Natural Science Foundation of China,No.81202625Open Fund of Key Laboratory of Cardiovascular and Cerebrovascular Diseases Translational Medicine of China Three Gorges University of China,No.2016xnxg101
文摘The fermented Chinese formula Shuan-Tong-Ling is composed of radix puerariae（Gegen）,salvia miltiorrhiza（Danshen）,radix curcuma（Jianghuang）,hawthorn（Shanzha）,salvia chinensis（Shijianchuan）,sinapis alba（Baijiezi）,astragalus（Huangqi）,panax japonicas（Zhujieshen）,atractylodes macrocephala koidz（Baizhu）,radix paeoniae alba（Baishao）,bupleurum（Chaihu）,chrysanthemum（Juhua）,rhizoma cyperi（Xiangfu） and gastrodin（Tianma）,whose aqueous extract was fermented with lactobacillus,bacillus aceticus and saccharomycetes.ShuanTong-Ling is a formula used to treat brain diseases including ischemic stroke,migraine,and vascular dementia.Shuan-Tong-Ling attenuated H_2O_2-induced oxidative stress in rat microvascular endothelial cells.However,the potential mechanism involved in these effects is poorly understood.Rats were intragastrically treated with 5.7 or 17.2 m L/kg Shuan-Tong-Ling for 7 days before middle cerebral artery occlusion was induced.The results indicated Shuan-Tong-Ling had a cerebral protective effect by reducing infarct volume and increasing neurological scores.Shuan-Tong-Ling also decreased tumor necrosis factor-α and interleukin-1β levels in the hippocampus on the ischemic side.In addition,Shuan-Tong-Ling upregulated the expression of SIRT1 and Bcl-2 and downregulated the expression of acetylated-protein 53 and Bax.Injection of 5 mg/kg silent information regulator 1（SIRT1） inhibitor EX527 into the subarachnoid space once every 2 days,four times,reversed the above changes.These results demonstrate that Shuan-Tong-Ling might benefit cerebral ischemia/reperfusion injury by reducing inflammation and apoptosis through activation of the SIRT1 signaling pathway.
基金This project is supported by National Natural Science Foundation of China(No.50575089).
文摘Proper meshing of Hy-Vo silent chain and sprocket is important for realizing the transmission of the silent chain with more efficiency and less noise. Based on the study of the meshing theory of the Hy-Vo silent chain with the sprocket and the roll cutting machining principle of the sprocket with the hob, the proper conditions of the meshing for the Hy-Vo silent chain and the sprocket are put forward with the variable pitch characteristic of the Hy-Vo silent chain taken into consideration, and the proper meshing design method on the condition that the value of the link tooth pressure angle is unequal to the value of the sprocket tooth pressure angle is studied. Experiments show that this new design method is feasible. In addition, the design of the pitch, the sprocket tooth pressure angle and the fillet radius of the sprocket addendum circle are studied. It is crucial for guiding the design of the hob which cuts the Hy-Vo silent chain sprocket.
基金This project is supported by National Natural Science Foundation of China (No.50275062)National Machine Industry Technique Development Foundation of China(No.99JA0002).
文摘Based on the study of the meshing theory of a new silent chain and sprockets, and the rolling cutting theory of sprocket and hob, the harmonious relations of dominating dimensions among the new silent chain, sprocket and hob is build, the meshing conditions are expatiated, and the resolved expression, which can instruct design and calculation, is educed. The tests show that the meshing design method is feasible.
基金Acknowledgments This work is supported by the Special Funds of National Natural Science Foundation of China （Grant No. 31071928）, the International Cooperation Project of National Natural Science Foundation of China （Grant No. 50920105504）, the Science Development Foundation of Jilin Province （Grant No. 20090340）, the Basic Research of High-speed Rail Joint Funds of the National Natural Science Foundation of China （Grant No. Ul134109）, and the Specialized Research Fund for the Doctoral Program of Higher Education of China （Grant No. 20110061120048）
文摘Many species of owls are able to fly noiselessly, and their wing feathers play an important role for the silent flight. In this paper, we studied the sound suppression mechanism of the eagle owl （Bubo bubo） by Stereo Microscope （SM）, Scanning Electron Microscopy （SEM） and Laser Scanning Confocal Microscope （LSCM）. To investigate the effects of special charac- teristics of wing feather on owl silent flight, the acoustic properties, including the sound absorption coefficient and flight noise, were compared between the eagle owl and common buzzard （Buteo buteo）. The results show that the eagle owl generates lower noise than common buzzard during flight, and its wing feather has better sound absorption properties. The leading edge serration and trailing edge fringe can improve the pressure fluctuation of turbulence boundary, and suppress the generation of vortex sound. The elongated distal barbules form a multi-layer grid porous structure which also has an effect on sound absorption. This research not only can give the inspiration for solving the aerodynamic noise of aircraft and engineering machine, but also can provide a new idea for the design of low-noise devices.
基金supported by American Diabetes Association,American Heart Association,NIH NIEHS,NIH NIA,NIH NINDS,and NIH ARRA
文摘Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy.The mechanistic target of rapamycin（m TOR） is a promising agent for the development of novel regenerative strategies for the treatment of DM.m TOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis,insulin resistance,insulin secretion,stem cell proliferation and differentiation,pancreatic β-cell function,and programmed cell death with apoptosis and autophagy.m TOR is central element for the protein complexes m TOR Complex 1（m TORC1） and m TOR Complex 2（m TORC2） and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase（PI 3-K）,protein kinase B（Akt）,AMP activated protein kinase（AMPK）,silent mating type information regulation 2 homolog 1（Saccharomyces cerevisiae）（SIRT1）,Wnt1 inducible signaling pathway protein 1（WISP1）,and growth factors.As a result,m TOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease.Future studies directed to elucidate the delicate balance m TOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.
基金Supported by National Natural Science Foundation of China(No.81273615)Zhejiang Provincial Natural Science Fund(No.Y2110849)
文摘Objective： To explore the mechanism of the protective effects of Panax notoginseng saponins（PNS） on kidney in diabetic rats. Methods： Diabetic rat model was obtained by intravenous injection of alloxan, and the rats were divided into model, PNS-100 mg/（kg·day） and PNS-200 mg/（kg·day） groups, 10 each. Another 10 rats injected with saline were served as control. Periodic acid-Schiff staining and immunological histological chemistry were used to observe histomorphology and tissue expression of bone morphogenetic protein-7（BMP-7）. Silent information regulator 1（SIRT1） was silenced in rat mesangial cells by RNA interference. The mR NA expressions of SIRT-1, monocyte chemoattractant protein-1（MCP-1）, transforming growth factor β1（TGF-β1） and plasminogen activator inhibitor-1（PAI-1） were analyzed by reverse transcription polymerase chain reaction. The protein expressions of SIRT1 and the acetylation of nuclear factor κB（NF-κB） P65 were determined by western blotting. The concentration of MCP-1, TGF-β1 and malondialdehyde（MDA） in culture supernatant were detected by enzyme-linked immuno sorbent assay. The activity of superoxide dismutase（SOD） was detected by the classical method of nitrogen and blue four. Results： In diabetic model rats, PNS could not only reduce blood glucose and lipid（P〈0.01）, but also increase protein level of BMP-7 and inhibit PAI-1 expression for suppressing fibrosis of the kidney. In rat mesangial cells, PNS could up-regulate the expression of SIRT1（P〈0.01） and in turn suppress the transcription of TGF-β1（P〈0.05） and MCP-1（P〈0.05）. PNS could also reverse the increased acetylation of NF-κB p65 by high glucose. In addition, redox regulation factor MDA was down-regulated（P〈0.05） and SOD was up-regulated（P〈0.01）, which were both induced by SIRT1 up-regulation. Conclusions： PNS could protect kidney from diabetes with the possible mechanism of up-regulating SIRT1, therefore inhibiting inflammation through dec
基金Supported by Aarhus University and the Danish Council for Independent Research,Medical Sciences,No.11-107912The Danish Strategic Research Council has supported the LIRMOI study on RSV effects in NAFLD and metabolic diseases,No.10-093499+5 种基金The NOVO Nordisk Foundation has supported Grnbk H by a research grantsupported by the Robert WStorr Bequest to the Sydney MedicalFoundation,University of Sydneya National Health and Medical Research Council of Australia (NHMRC) Program Grant No.1053206Project grants 632630 and 1049857
文摘The prevalence of obesity and related conditions like non-alcoholic fatty liver disease(NAFLD) is increasing worldwide and therapeutic options are limited.Alternative treatment options are therefore intensively sought after.An interesting candidate is the natural polyphenol resveratrol(RSV) that activates adenosinmonophosphate-activated protein kinase(AMPK) and silent information regulation-2 homolog 1(SIRT1).In addition,RSV has known anti-oxidant and anti-inflammatory effects.Here,we review the current evidence for RSVmediated effects on NAFLD and address the different aspects of NAFLD and non-alcoholic steatohepatitis(NASH) pathogenesis with respect to free fatty acid(FFA) flux from adipose tissue,hepatic de novo lipogenesis,inadequate FFA β-oxidation and additional intra- and extrahepatic inflammatory and oxidant hits.We review the in vivo evidence from animal studies and clinical trials.The abundance of animal studies reports a decrease in hepatic triglyceride accumulation,liver weight and a general improvement in histological fatty liver changes,along with a reduction in circulating insulin,glucose and lipid levels.Some studies document AMPK or SIRT1 activation,and modulation of relevant markers of hepatic lipogenesis,inflammation and oxidation status.However,AMPK/SIRT1-independent actions are also likely.Clinical trials are scarce and have primarily been performed with a focus on overweight/obese participants without a focus on NAFLD/NASH and histological liver changes.Future clinical studies with appropriate design are needed to clarify the true impact of RSV treatment in NAFLD/NASH patients.
基金National Natural Science Foundation of China(81560666)Program for Excellent Young Talents of Zunyi Medical Uiverstity(15zy-002)+1 种基金Science and Technology Innovation Talent Team of Guizhou Province(20154023)the ″Hundred″Level of High-level Innovative Talents in Guizhou Province(QKHRCPT 20165684)；and Program forChangjiang Scholars and Innovative ResearchTeam in University of China(IRT一17R113).
文摘OBJECTIVE To investigate icariside(ICS)Ⅱ protects against PC12 cel damage induced by oxygen-glucose deprivation and reoxygenation and explore its mechanism.METHODS The oxidative stress injury model was induced by oxygen-glucose deprivation/reoxygenation(OGD/R) 2 h/24 h in PC12 cells.N-acetyl-lcysteine(NAC),a classical anti-oxidant,was used as positive control.Pharmacodynamic experimental study groups as follows:control,control+ICS Ⅱ50 μmol·L^(-1),OGD/R,OGD/R+ICSⅡ 12.5 μmol·L^(-1),OGD/R + ICS Ⅱ 25 μmol·L^(-1),OGD/R + ICS Ⅱ50 μmol·L^(-1),and OGD/R+NAC 100 μmol·L^(-1) groups.Cell viability and lactate dehydrogenase(LDH) leakage rate were measured by MTT assay and LDH ELISA kit,respectively.Moreover,reactive oxygen species(ROS) ELISA kit was used for detection of intracellular ROS generation,Mito-SOX fluorescence staining was used for detecting production of ROS in mitochondria and mitochondrial membrane potential(MMP)was detected by rhodamine 123 dye.In addition,PC12 cells apoptosis was detected by one-step TUNEL assay.Furthermore,the expressions of nuclear factor erythroid 2-related factors(Nrf2),Keap1,HO^(-1),NQO^(-1),silent information regulator 3(SIRT3),IDH2,Bax,Bcl-2 and caspase 3 were detected by Western blotting analysis.RESULTS The results of MTT and LDH assay showed that OGD/R reduced the cell viability and improved LDH release compared with the control or ICSⅡ 50 μmol·L^(-1) alone(P<0.01).Meanwhile,OGD/R not only increased intracellular and mitochondrial ROS generation,but also elevated the fluorescence intensity of TUNEL staining,at the same time,the MMP was declined when challenged by OGD/R.Furthermore,the Western blotting results showed that OGD/R induced the increase in the expression of cytoplasm-Nrf2,Keap1,Bax and cleaved-caspase 3 level,while the decrease in the expression of nucleus-Nrf2,HO^(-1),NQO^(-1),SIRT3,IDH2 and Bcl-2(P<0.05).However,ICS Ⅱ significantly increased the viability of PC12 cells and reduced LDH leakage(P<0.01).Notably,ICS Ⅱ also suppressed ROS generati
基金Supported by the National Natural Science Foundation of China(No.81170836No.81570838)+1 种基金the Natural Science Foundation of Liaoning Province,China(No.2015020474)the Liaoning Provincial Hospital Program for Building Treatment Capacity in Key Clinical Departments(No.LNCCC-D15-2015)
文摘AIM： To detect the expression of miR-211 in age-related cataract tissue, explore the effects of miR-211 on lens epithelial cell proliferation and apoptosis, and identify its target gene.METHODS： This study used real-time quantitative polymerase chain reaction（RT-q PCR） to measure the expression of miR-211 and its predicted target gene [silent matingtype information regulation 2 homolog 1（SIRT1）] in 46 anterior lens capsules collected from age-related cataract patients. Human lens epithelial cell line（SRA01/04） cells were transfected with either miR-211 mimics, mimic controls, miR-211 inhibitors or inhibitor controls, 72 h after transfection, miR NA and protein expression of SIRT1 were measured using RT-qP CR and Western blotting; then cells were exposed to 200 μmol/L H2O2 for 1h, whereupon cell viability was measured by MTS assay, caspase-3 assay was performed. Dual luciferase reporter assay was performed to verify the relationship between miR-211 of SIRT1.RESULTS： Compared to the control group, expression of miR-211 was significantly increased（P〈0.001）, the miR NA and protein expression of SIRT1 were significantly decreased（P〈0.001） in the anterior lens capsules of patients with age-related cataracts. Relative to the control group, SIRT1 miR NA and protein levels in the miR-211 mimic group were significantly reduced, cell proliferation activity significantly decreased, and caspase-3 activity was significantly increased（P〈0.001）. In the miR-211 inhibitor group, SIRT1 miRNA and protein expression were significantly increased, cell proliferation activity significantly increased, and caspase-3 activity was significantly decreased（P〈0.001）. A dual luciferase reporter assay confirmed that SIRT1 is a direct target of miR-211.CONCLUSION： miR-211 is highly expressed in the anterior lens capsules of patients with age-related cataracts. By negatively regulating the expression of SIRT1, miR-211 promotes lens epithelial cell apoptosis and inhibits lens epithelial cell proliferatio
文摘The development of sensitive assays to detect small amounts of hepatitis B virus(HBV) DNA has favored the identification of occult hepatitis B infection(OBI), a virological condition characterized by a low level of HBV replication with detectable levels of HBV DNA in liver tissue but an absence of detectable surface antigen of HBV(HBs Ag) in serum. The gold standard to diagnose OBI is the detection of HBV DNA in the hepatocytes by highly sensitive and specific techniques, a diagnostic procedure requiring liver tissue to be tested and the use of non-standardized non-commercially available techniques. Consequently, in everyday clinical practice, the detection of anti-hepatitis B core antibody(antiHBc) in serum of HBs Ag-negative subjects is used as a surrogate marker to identify patients with OBI. In patients with chronic hepatitis C(CHC), OBI has been identified in nearly one-third of these cases. Considerable data suggest that OBI favors the increase of liver damage and the development of hepatocellular carcinoma(HCC) in patients with CHC. The data from other studies, however, indicate no influence of OBI on the natural history of CHC, particularly regarding the risk of developing HCC.
基金Supported by National Natural Science Foundation of China,No.82060123Doctoral Start-up Fund of Affiliated Hospital of Guizhou Medical University,No.gysybsky-2021-28+1 种基金Fund Project of Guizhou Provincial Science and Technology Department,No.[2020]1Y299Guizhou Provincial Health Commission,No.gzwjk2019-1-082。
文摘BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rat
基金supported by American Diabetes AssociationAmerican Heart Association+3 种基金National Institutes of Health-National Institute of Environmental Health SciencesNational Institutes of Health-National Institute on AgingNational Institutes of Health-National Institute of Neurological DisordersNational Institutes of Health-American Recovery and Reinvestment(to KM)。
文摘The global increase in lifespan noted not only in developed nations,but also in large developing countries parallels an observed increase in a significant number of noncommunicable diseases,most notable neurodegenerative disorders.Neurodegenerative disorders present a number of challenges for treatment options that do not resolve disease progression.Furthermore,it is believed by the year 2030,the services required to treat cognitive disorders in the United States alone will exceed$2 trillion annually.Mammalian forkhead transcription factors,silent mating type information regulation 2 homolog 1(Saccharomyces cerevisiae),the mechanistic target of rapamycin,and the pathways of autophagy and apoptosis offer exciting avenues to address these challenges by focusing upon core cellular mechanisms that may significantly impact nervous system disease.These pathways are intimately linked such as through cell signaling pathways involving protein kinase B and can foster,sometimes in conjunction with trophic factors,enhanced neuronal survival,reduction in toxic intracellular accumulations,and mitochondrial stability.Feedback mechanisms among these pathways also exist that can oversee reparative processes in the nervous system.However,mammalian forkhead transcription factors,silent mating type information regulation 2 homolog 1,mechanistic target of rapamycin,and autophagy can lead to cellular demise under some scenarios that may be dependent upon the precise cellular environment,warranting future studies to effectively translate these core pathways into successful clinical treatment strategies for neurodegenerative disorders.
基金Supported by the National Natural Science Foundation of China(Nos.81173449,81473466)。
文摘Objective:To observe the changes of ischemic myocardial cells apoptosis in rats following intervention with Xuefu Zhuyu Oral Liquid(血府逐瘀口服液,XFZY),as well as changes of protein expression of silent information regulator 1(SIRT1)and SIRT1 pathway-related genes.Methods:H9c2 rat myocardial cells were divided into 6 groups:control group,oxygen glucose deprivation(OGD)group,SIRT1 siRNA group,OGD+SIRT1 siRNA group,OGD+XFZY group,and OGD+SIRT1 siRNA+XFZY group.Quantitative fluorescent polymerase chain reaction(PCR)and Western blot were used to detect the concentration variations of SIRT1 and its pathway-related genes and corresponding protein expression after XFZY intervention and SIRT1 transfection.Results:Compared with the control group,the mRNA and protein expressions of SIRT1 were decreased obviously,while the mRNA and protein levels of P53,forkhead box protein O1(FoxO1),FoxO3,FoxO4 and nuclear factor kappa B(NF-κB)were increased in the OGD group,SIRT1 siRNA group,and OGD+SIRT1 siRNA group(P<0.01).Compared with the OGD group and OGD+SIRT1 siRNA group,the treatment of XFZY inhibited the decline in SIRT1 mRNA and protein expressions(P<0.01),and down-regulated the mRNA and protein levels of P53,FoxO1,FoxO3,FoxO4 and NF-κB,respectively(P<0.05 or P<0.01).Conclusion:XFZY could prevent myocardial cells apoptosis probably by increasing the mRNA and protein expressions of SIRT1 and inhibiting the mRNA and protein expressions of P53,NF-κB,FoxO1,FoxO3 and FoxO4.
