AIM: To investigate the antif ibrotic effects of peginterferon- alpha 2b and taurine on oxidative stress markers and hepatocellular apoptosis. METHODS: Sixty rats with CCl4-induced liver fibrosis were divided into 4 g...AIM: To investigate the antif ibrotic effects of peginterferon- alpha 2b and taurine on oxidative stress markers and hepatocellular apoptosis. METHODS: Sixty rats with CCl4-induced liver fibrosis were divided into 4 groups (n = 15). Group 1 was left for spontaneous recovery (SR). Groups 2-4 received peginterferon-alpha 2b, taurine, and their combination, respectively, for four weeks. Histological f ibrosis scores, histomorphometric analysis, tissue hydroxyproline, tissue MDA, GPx and SOD activities were determined. Activated stellate cells and hepatocellular apoptosis were also evaluated. RESULTS: The degree of f ibrosis decreased in all treatment groups compared to spontaneous recovery group. Taurine alone and in combination with peginterferon-alpha 2b reduced oxidative stress markers, but peginterferon-alpha 2b alone did not. Apoptotic hepatocytes and activated stellate cells were higher in groups 2-4 than in group 1. Combined taurine and peginterferon-alpha 2b further reduced fibrosis and increased activated stellate cell apoptosis, but could not improve oxidative stress more than taurine alone.CONCLUSION: Peginterferon-alpha 2b exerts anti- f ibrotic effects on rat liver fibrosis. It seems ineffective against oxidative stress in vivo. Peginterferon-alpha 2b in combination with taurine seems to be an antif ibrotic strategy.展开更多
The main goals of treating cirrhotic patients with antiviral therapy are to attain sustained viral clearance(SVR),halt disease progression,and prevent re-infection of the liver graft.However,while the medical need is ...The main goals of treating cirrhotic patients with antiviral therapy are to attain sustained viral clearance(SVR),halt disease progression,and prevent re-infection of the liver graft.However,while the medical need is great,the use of interferon and ribavirin might expose these patients to severe treated-related side effects as a large proportion of them have pre-existing hematological cytopenias.We have reviewed potential benefits and risks associated with antiviral drugs in patients with liver cirrhosis,due to hepatitis C virus(HCV) infection.In cases presenting with bridging fibrosis or cirrhosis,current regimens of antiviral therapy have attained a 44%-48% rate of SVR.In cirrhotic patients with portal hypertension,the SVR rate was 22% overall,12.5% in patients with genotype 1,and 66.7% in those with genotypes 2 and 3 following therapy with low doses of either Peg-IFN alpha-2b and of ribavirin.In patients with decompensated cirrhosis,full dosages of Peg-IFN alpha-2b and of ribavirin produced a SVR rate of 35% overall,16% in patients with genotype 1 and 4,and 59% in those with genotype 2 and 3.Use of hematological cytokines will either ensure full course of treatment to be accomplished with and prevent development of treatment-associated side effects.Major benefits after HCV eradication were partial recovery of liver metabolic activity,prevention of hepatitis C recurrence after transplantation,and removal of some patients from the waiting list for liver transplant.Several observations highlighted that therapy is inadvisable for individuals with poor hepatic reserve(Child-Pugh-Turcotte score ≥ 10).Although SVR rates are low indecompensated cirrhotics due to hepatitis C,these patients have the most to gain as successful antiviral therapy is potentially lifesaving.展开更多
AIM： To assess the long-term clinical benefit of sustained virological response （SVR） in patients with hepatitis C virus （HCV） cirrhosis treated by antiviral therapy using mostly ribavirin plus interferon either ...AIM： To assess the long-term clinical benefit of sustained virological response （SVR） in patients with hepatitis C virus （HCV） cirrhosis treated by antiviral therapy using mostly ribavirin plus interferon either standard or pegylated.METHODS： One hundred and thirteen patients with uncomplicated HCV biopsy-proven cirrhosis, treated by at least one course of antiviral treatment ≥ 3 mo and followed ≥ 30 mo were included. The occurrence of clinical events [hepatocellular carcinoma （HCC）, decompensation and death] was compared in SVR and non SVR patients.RESULTS： Seventy eight patients received bitherapy and 63 had repeat treatments. SVR was achieved in 37 patients （33%）. During a mean follow-up of 7.7 years, clinical events occurred more frequently in non SVR than in SVR patients, with a significant difference for HCC （24/76 vs 1/37, P = 0.01）. No SVR patient died while 20/76 non-SVR did （P = 0.002）, mainly in relation to HCC （45%）.CONCLUSION： In patients with HCV-related cirrhosis, $VR is associated with a significant decrease in the incidence of HCC and mortality during a follow-up period of 7.7 years. This result is a strong argument to perform and repeat antiviral treatments in patients with compensated cirrhosis.展开更多
An attempt was made to improve the surface properties of the AZ91 Mg alloy through surface alloying of a mixture of Al and TiC with the help of TIG arc as heat source.The microstructural evolution of the alloyed layer...An attempt was made to improve the surface properties of the AZ91 Mg alloy through surface alloying of a mixture of Al and TiC with the help of TIG arc as heat source.The microstructural evolution of the alloyed layer on the AZ91 alloy was analysed through SEM and XRD technique.The micro-hardness and the dry sliding wear behaviour were assessed by Vickers micro-hardness tester and pin-on-disc wear test setup,respectively.It is revealed that almost uniform alloyed layer forms on the AZ91 alloy substrate for a specific current and scan speed employed in the present experiments.The alloyed layer exhibits hardness value up to 305 HV0.25,and almost negligible wear as compared to the as-received AZ91 alloy substrate.展开更多
Titanium alloys are poor in wear resistance and it is not suitable under sliding conditions even with lubrication because ofits severe adhesive wear tendency.The surface modifications through texturing and surface coa...Titanium alloys are poor in wear resistance and it is not suitable under sliding conditions even with lubrication because ofits severe adhesive wear tendency.The surface modifications through texturing and surface coating were used to enhance the surfaceproperties of the titanium alloy substrate.Hard and wear resistant coatings such as TiAlN and AlCrN were applied over texturedtitanium alloy surfaces with chromium as interlayer.To improve the friction and wear resisting performance of hard coatings further,solid lubricant,molybdenum disulphide(MoS2),was deposited on dimples made over hard coatings.Unidirectional sliding weartests were performed with pin on disc contact geometry,to evaluate the tribological performance of coated substrates.The tests wereperformed under three different normal loads for a period of40min at sliding velocity of2m/s.The tribological behaviours ofmulti-layer coatings such as coating structure,friction coefficient and specific wear rate were investigated and analyzed.The lowerfriction coefficient of approximately0.1was found at the early sliding stage,which reduces the material transfer and increases thewear life.Although,the friction coefficient increased to high values after MoS2coating was partially removed,substrate was stillprotected against wear by underlying hard composite layer.展开更多
The effects of anodizing conditions （electrolyte, current density and temperature） on the friction coefficient and Vickers mierohardness of anodic oxide layers formed on A1 5754 and A1 1050A substrates were investig...The effects of anodizing conditions （electrolyte, current density and temperature） on the friction coefficient and Vickers mierohardness of anodic oxide layers formed on A1 5754 and A1 1050A substrates were investigated. The studied properties were examined using DELTALAB HVS-1000 Vickers mierohardness tester and rotating pin on disc tribometer. It was established that the highest microhardness （〉HV 400） and the lowest friction coefficient （〈0.4） were obtained with the oxalic acid addition of 10 g/L at high current density of 3 A/dm2 and low temperature of 5 ~C. The presence of oxidized Mg through the anodic oxide layer formed on A1 5754 was examined using glow-discharge optical emission spectroscopy （GDOES）. The MgO was found to act negatively on the mechanical property of the layer. Finally, the scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDS）, and atomic force microscopy （AFM） were used to characterize the anodic layer before and after friction tests. It is found that the wear mechanism is related to many aspects of the initial morphology, chemical composition of the layer （C, S and Mg）, porosity and internal stress.展开更多
Three aspects of RS 485 application, which affect the reliability of communication of data system are analyzed and discussed. In network configuration, it presents the optimal configuration for the bus of RS 485, the ...Three aspects of RS 485 application, which affect the reliability of communication of data system are analyzed and discussed. In network configuration, it presents the optimal configuration for the bus of RS 485, the better rule for derivative line and the choice for termination. In hardware design, it presents three parts of driver’s peripheral circuit. In control software design, it presents a method of using 75176’s DE line to control the driver.展开更多
Coatings of metal matrix composites(Cu?WC)were fabricated by solid-state sintering.WC reinforcing particles indifferent quantities from5%up to30%(volume fraction)were mixed with Cu particles.After mixing,the powders w...Coatings of metal matrix composites(Cu?WC)were fabricated by solid-state sintering.WC reinforcing particles indifferent quantities from5%up to30%(volume fraction)were mixed with Cu particles.After mixing,the powders were poured ontothe surface of copper substrates.Sintering was carried out at1000°C under a reducing atmosphere in a vertical dilatometer.Sinteringkinetics was affected by both rigid substrates and WC particles which retarded the radial and axial densification of powders.However,the coatings were strongly attached to the substrate,and WC particles were randomly distributed within the matrix.The addition ofthe reinforcing particles enhanced the microhardness and reduced the volume loss in wear tests to1/17compared to the unreinforcedsample.The predominant wear mechanism was identified as abrasion at a load of5N.20%WC(volume fraction)reinforcingparticles led to the maximum values of properties for the composite coating.展开更多
Chronic hepatitis C is a leading cause of morbidity and mortality, mainly related to fibrosis/cirrhosis and portal hypertension. Direct antiviral agents are highly effective and safe and can now cure > 90% of the p...Chronic hepatitis C is a leading cause of morbidity and mortality, mainly related to fibrosis/cirrhosis and portal hypertension. Direct antiviral agents are highly effective and safe and can now cure > 90% of the patients. Sustained viral response (SVR) after interferon-based regimens has been associated with improvement in liver function, fibrosis and portal hypertension in a significant proportion of patients, although a point of no return seems to exist from which viral elimination is no longer capable of preventing portal hypertension progression and liver decompensation. Indeed, although SVR is associated with improvement of hepatic venous pressure gradients and therefore a decreased risk of de novo esophageal varices, several studies show that viral clearance does not eliminate the risk of variceal progression, liver decompensation and death in patients with pre-established portal hypertension. Although evidence about the effects of direct antiviral agents (DAAs) on clinically significant outcomes is still scarce and with short follow-up, DAAs can decrease the burden of the disease if patients are timely treated before significant fibrosis and portal hypertension develops. Studies with longer follow-up are waited to establish the real magnitude of hepatitis C treatment on portal hypertension. Future studies should also focus on predictors of portal hypertension resolution since it can influence management and avoid unnecessary monitoring展开更多
The lifetime of roll-bits with inserted tooth will be obviously decreased while drilling in strata and the tungsten carbide can be integrally separated from the roll-cone,which will need more trip out time to replace ...The lifetime of roll-bits with inserted tooth will be obviously decreased while drilling in strata and the tungsten carbide can be integrally separated from the roll-cone,which will need more trip out time to replace the roller bit.This study provides an entire analysis on stress as well as strength for teeth and tooth holes in loaded conditions.Qualities of tooth drop from matrix within roller bit.The optimized interferences of teeth inserted into the bit can be reasonably obtained by the critical interference derived from some relevant influence factors on the tooth-fixing quality of roller bits.展开更多
基金Supported by the Gulhane School of Medicine Research Council (AR-02-15)
文摘AIM: To investigate the antif ibrotic effects of peginterferon- alpha 2b and taurine on oxidative stress markers and hepatocellular apoptosis. METHODS: Sixty rats with CCl4-induced liver fibrosis were divided into 4 groups (n = 15). Group 1 was left for spontaneous recovery (SR). Groups 2-4 received peginterferon-alpha 2b, taurine, and their combination, respectively, for four weeks. Histological f ibrosis scores, histomorphometric analysis, tissue hydroxyproline, tissue MDA, GPx and SOD activities were determined. Activated stellate cells and hepatocellular apoptosis were also evaluated. RESULTS: The degree of f ibrosis decreased in all treatment groups compared to spontaneous recovery group. Taurine alone and in combination with peginterferon-alpha 2b reduced oxidative stress markers, but peginterferon-alpha 2b alone did not. Apoptotic hepatocytes and activated stellate cells were higher in groups 2-4 than in group 1. Combined taurine and peginterferon-alpha 2b further reduced fibrosis and increased activated stellate cell apoptosis, but could not improve oxidative stress more than taurine alone.CONCLUSION: Peginterferon-alpha 2b exerts anti- f ibrotic effects on rat liver fibrosis. It seems ineffective against oxidative stress in vivo. Peginterferon-alpha 2b in combination with taurine seems to be an antif ibrotic strategy.
文摘The main goals of treating cirrhotic patients with antiviral therapy are to attain sustained viral clearance(SVR),halt disease progression,and prevent re-infection of the liver graft.However,while the medical need is great,the use of interferon and ribavirin might expose these patients to severe treated-related side effects as a large proportion of them have pre-existing hematological cytopenias.We have reviewed potential benefits and risks associated with antiviral drugs in patients with liver cirrhosis,due to hepatitis C virus(HCV) infection.In cases presenting with bridging fibrosis or cirrhosis,current regimens of antiviral therapy have attained a 44%-48% rate of SVR.In cirrhotic patients with portal hypertension,the SVR rate was 22% overall,12.5% in patients with genotype 1,and 66.7% in those with genotypes 2 and 3 following therapy with low doses of either Peg-IFN alpha-2b and of ribavirin.In patients with decompensated cirrhosis,full dosages of Peg-IFN alpha-2b and of ribavirin produced a SVR rate of 35% overall,16% in patients with genotype 1 and 4,and 59% in those with genotype 2 and 3.Use of hematological cytokines will either ensure full course of treatment to be accomplished with and prevent development of treatment-associated side effects.Major benefits after HCV eradication were partial recovery of liver metabolic activity,prevention of hepatitis C recurrence after transplantation,and removal of some patients from the waiting list for liver transplant.Several observations highlighted that therapy is inadvisable for individuals with poor hepatic reserve(Child-Pugh-Turcotte score ≥ 10).Although SVR rates are low indecompensated cirrhotics due to hepatitis C,these patients have the most to gain as successful antiviral therapy is potentially lifesaving.
文摘AIM： To assess the long-term clinical benefit of sustained virological response （SVR） in patients with hepatitis C virus （HCV） cirrhosis treated by antiviral therapy using mostly ribavirin plus interferon either standard or pegylated.METHODS： One hundred and thirteen patients with uncomplicated HCV biopsy-proven cirrhosis, treated by at least one course of antiviral treatment ≥ 3 mo and followed ≥ 30 mo were included. The occurrence of clinical events [hepatocellular carcinoma （HCC）, decompensation and death] was compared in SVR and non SVR patients.RESULTS： Seventy eight patients received bitherapy and 63 had repeat treatments. SVR was achieved in 37 patients （33%）. During a mean follow-up of 7.7 years, clinical events occurred more frequently in non SVR than in SVR patients, with a significant difference for HCC （24/76 vs 1/37, P = 0.01）. No SVR patient died while 20/76 non-SVR did （P = 0.002）, mainly in relation to HCC （45%）.CONCLUSION： In patients with HCV-related cirrhosis, $VR is associated with a significant decrease in the incidence of HCC and mortality during a follow-up period of 7.7 years. This result is a strong argument to perform and repeat antiviral treatments in patients with compensated cirrhosis.
文摘An attempt was made to improve the surface properties of the AZ91 Mg alloy through surface alloying of a mixture of Al and TiC with the help of TIG arc as heat source.The microstructural evolution of the alloyed layer on the AZ91 alloy was analysed through SEM and XRD technique.The micro-hardness and the dry sliding wear behaviour were assessed by Vickers micro-hardness tester and pin-on-disc wear test setup,respectively.It is revealed that almost uniform alloyed layer forms on the AZ91 alloy substrate for a specific current and scan speed employed in the present experiments.The alloyed layer exhibits hardness value up to 305 HV0.25,and almost negligible wear as compared to the as-received AZ91 alloy substrate.
文摘Titanium alloys are poor in wear resistance and it is not suitable under sliding conditions even with lubrication because ofits severe adhesive wear tendency.The surface modifications through texturing and surface coating were used to enhance the surfaceproperties of the titanium alloy substrate.Hard and wear resistant coatings such as TiAlN and AlCrN were applied over texturedtitanium alloy surfaces with chromium as interlayer.To improve the friction and wear resisting performance of hard coatings further,solid lubricant,molybdenum disulphide(MoS2),was deposited on dimples made over hard coatings.Unidirectional sliding weartests were performed with pin on disc contact geometry,to evaluate the tribological performance of coated substrates.The tests wereperformed under three different normal loads for a period of40min at sliding velocity of2m/s.The tribological behaviours ofmulti-layer coatings such as coating structure,friction coefficient and specific wear rate were investigated and analyzed.The lowerfriction coefficient of approximately0.1was found at the early sliding stage,which reduces the material transfer and increases thewear life.Although,the friction coefficient increased to high values after MoS2coating was partially removed,substrate was stillprotected against wear by underlying hard composite layer.
基金supported by the Ministry of Higher Education and Scientific Research,Tunisia
文摘The effects of anodizing conditions （electrolyte, current density and temperature） on the friction coefficient and Vickers mierohardness of anodic oxide layers formed on A1 5754 and A1 1050A substrates were investigated. The studied properties were examined using DELTALAB HVS-1000 Vickers mierohardness tester and rotating pin on disc tribometer. It was established that the highest microhardness （〉HV 400） and the lowest friction coefficient （〈0.4） were obtained with the oxalic acid addition of 10 g/L at high current density of 3 A/dm2 and low temperature of 5 ~C. The presence of oxidized Mg through the anodic oxide layer formed on A1 5754 was examined using glow-discharge optical emission spectroscopy （GDOES）. The MgO was found to act negatively on the mechanical property of the layer. Finally, the scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDS）, and atomic force microscopy （AFM） were used to characterize the anodic layer before and after friction tests. It is found that the wear mechanism is related to many aspects of the initial morphology, chemical composition of the layer （C, S and Mg）, porosity and internal stress.
文摘Three aspects of RS 485 application, which affect the reliability of communication of data system are analyzed and discussed. In network configuration, it presents the optimal configuration for the bus of RS 485, the better rule for derivative line and the choice for termination. In hardware design, it presents three parts of driver’s peripheral circuit. In control software design, it presents a method of using 75176’s DE line to control the driver.
基金CONACy T through the project CB-167111the Scientific Research Department of the UMSNH and the Guadalajara University for the financial support and the facilities to develop this study
文摘Coatings of metal matrix composites(Cu?WC)were fabricated by solid-state sintering.WC reinforcing particles indifferent quantities from5%up to30%(volume fraction)were mixed with Cu particles.After mixing,the powders were poured ontothe surface of copper substrates.Sintering was carried out at1000°C under a reducing atmosphere in a vertical dilatometer.Sinteringkinetics was affected by both rigid substrates and WC particles which retarded the radial and axial densification of powders.However,the coatings were strongly attached to the substrate,and WC particles were randomly distributed within the matrix.The addition ofthe reinforcing particles enhanced the microhardness and reduced the volume loss in wear tests to1/17compared to the unreinforcedsample.The predominant wear mechanism was identified as abrasion at a load of5N.20%WC(volume fraction)reinforcingparticles led to the maximum values of properties for the composite coating.
文摘Chronic hepatitis C is a leading cause of morbidity and mortality, mainly related to fibrosis/cirrhosis and portal hypertension. Direct antiviral agents are highly effective and safe and can now cure > 90% of the patients. Sustained viral response (SVR) after interferon-based regimens has been associated with improvement in liver function, fibrosis and portal hypertension in a significant proportion of patients, although a point of no return seems to exist from which viral elimination is no longer capable of preventing portal hypertension progression and liver decompensation. Indeed, although SVR is associated with improvement of hepatic venous pressure gradients and therefore a decreased risk of de novo esophageal varices, several studies show that viral clearance does not eliminate the risk of variceal progression, liver decompensation and death in patients with pre-established portal hypertension. Although evidence about the effects of direct antiviral agents (DAAs) on clinically significant outcomes is still scarce and with short follow-up, DAAs can decrease the burden of the disease if patients are timely treated before significant fibrosis and portal hypertension develops. Studies with longer follow-up are waited to establish the real magnitude of hepatitis C treatment on portal hypertension. Future studies should also focus on predictors of portal hypertension resolution since it can influence management and avoid unnecessary monitoring
文摘The lifetime of roll-bits with inserted tooth will be obviously decreased while drilling in strata and the tungsten carbide can be integrally separated from the roll-cone,which will need more trip out time to replace the roller bit.This study provides an entire analysis on stress as well as strength for teeth and tooth holes in loaded conditions.Qualities of tooth drop from matrix within roller bit.The optimized interferences of teeth inserted into the bit can be reasonably obtained by the critical interference derived from some relevant influence factors on the tooth-fixing quality of roller bits.
