Extreme ground behaviour in high-stress rock masses such as rockburst prone and squeezing ground conditions are encountered in a range of underground projects both in civil and mining applications.The occurrence of su...Extreme ground behaviour in high-stress rock masses such as rockburst prone and squeezing ground conditions are encountered in a range of underground projects both in civil and mining applications.The occurrence of such ground behaviour types are difficult to predict and special design and construction measures must be taken to control them.Determining the most appropriate support system in such grounds is one of the major challenges for ground control engineers because there are many contributing factors to be considered,such as the rock mass parameters,the stress condition,the type and performance of the support systems,the condition of major geological structures and the size and geometry of the underground excavation.The main characteristics and support requirements of rockburst-prone and squeezing ground conditions are herein critically reviewed and characteristics of support functions are discussed.Different types of energy-absorbing rockbolts and other support elements applicable for ground support in burst-prone and squeezing grounds are introduced.Important differences in the choice and economics of ground support strategies in high-stress ground conditions between civil tunnels and mining excavations are discussed.Ground support benchmarking data and mitigation measures for mines and civil tunnels in burst-prone,squeezing and heavily swelling grounds conditions are briefly presented by some examples in practice.展开更多
Rockbolt is widely employed all over the world as an effective ground reinforcement element in order to secure the underground workplaces.Ordinary encapsulated rebar or rebar rockbolt is most popular and commonly used...Rockbolt is widely employed all over the world as an effective ground reinforcement element in order to secure the underground workplaces.Ordinary encapsulated rebar or rebar rockbolt is most popular and commonly used as reinforcement in a ground support system because of its accessibility,cost effectiveness and easy practicability.Reinforcement elements in a seismic condition such as rock burst have to dissipate the energy release of the dynamic impact via their deformation and ultimate load capacity,knowing that the former is more important.In other words,achieving early stiff behaviour along with large deformation capacity in rockbolts are the goals for new development in rock reinforcement.Yielding rockbolts are expensive while some of them have large deformation capability with low ultimate load capacity.In this paper,modifications were made on encapsulation of rebar rockbolts to utilise it effectively as a yielding reinforcement in seismic conditions.Applying a sufficient decoupled length in the shank of rebar rockbolts which industry has regularly been using to control the bulking of the stress fractured ground,improves the deformation capacity of the bolt.Additionally,leaving a collar bonding underneath of the bearing pad and plate removes the weaknesses of the head anchorage of rockbolt.Therefore the dynamic performance of the bolt is improved by these easily applicable modifications.The behaviour and performance of encapsulated rockbolts have been discussed first,then the effects of modifications are illustrated.The proposed modification of the rebars is not only cost effective but also easy to apply in the field and improves the performance of reinforcements in seismic prone zones.展开更多
Objective: To compare the bone mass density in chronic hepatitis patients before and after interferon-a treatment.Methods: A total of 70 patients with chronic hepatitis C were treated with interferon-a and were evalua...Objective: To compare the bone mass density in chronic hepatitis patients before and after interferon-a treatment.Methods: A total of 70 patients with chronic hepatitis C were treated with interferon-a and were evaluated. The treatment dosage was three million IU three times a week for one year. All the patients underwent bone mass density detection at lumbar spine and femoral neck before and after the interferon-a treatment. All the necessary information such as age,sex, and laboratory test, history of occurrence of fractures, lifestyle, and menopause status was collected by interviewers face-to-face from participants at the research visit. Smoking was categorized by whether participants were nonsmokers or smokers. Menopause was designated if there had been complete cessation of menses for more than 12 months. All statistical analyses were performed by SPSS version 14(SPSS, Inc., Chicago, IL, USA).Results: Among 70 patients, 52% were male, 48% were female and the mean age was(57.0 ± 9.6) years(range: 24–79). Twenty-nine percent of the patients had a history of smoking. The mean body mass index was(24.4 ± 3.6) kg/m^2(range: 18.4–35.3). Of the70 cases, 21 had high fibrosis-4. The prevalence of overall fracture history was 2.9%(two patients).Conclusions: Chronic hepatitis C virus infection did increase the risk of development of metabolic bone disease in this cohort. Indeed, greater reduction of bone mass density occurs in advanced liver fibrosis. The bone loss in earlier stages of chronic hepatitis C infection is likely to result from increased bone reduction rather than decreased bone formation. Overall, these observations suggest an important role for chronic hepatitis C virus infection in increased bone turnover in osteodystrophy pathogenesis.展开更多
Objective: To develop a gold nanoparticles complex conjugated with interferon-gamma(IFN-g) and methionine along with application of hyperthermia using near-infrared laser beams for the treatment of cancer cells.Method...Objective: To develop a gold nanoparticles complex conjugated with interferon-gamma(IFN-g) and methionine along with application of hyperthermia using near-infrared laser beams for the treatment of cancer cells.Methods: Gold nanorods(10 nm) were conjugated with IFN-g and methionine using carbodiimide family and characterized after purification by dialysis bags. Breast cancer cells were cultured and incubated with gold nanorods at different concentrations followed by irradiation with near-infrared laser beam. Samples were then evaluated for their viability in order to determine the effect of treatment and variables by MTT assy.Results: Zetasizer results confirmed the conjugation of gold nanorods with methionine and IFN-g. The median percentage of cell viability in 0.30 mg/m L concentration of gold nanorods was 82%. The cell viability reached to 85% at the same concentration of gold nanorods, which existed in the assayed complex. The results of MTT assay showed that the 0.60 mg/m L concentration of gold nanoparticles complex was toxic on tumor cells(P < 0.05). After exposure to hyperthermia, the viability of cells at 6 min decreased to77% in 0.30 mg/m L concentration of gold nanorods complex.Conclusions: The size and concentration of gold nanorods was not cytotoxic. However,their presence during irradiation near-infrared laser increased the number of dead cells during the treatment of cells.展开更多
Senescence or programmed cell death is a process that interacts with many biochemical and physiological changes in living organism and is generally induced by aging. Many environmental stresses that accelerate the pro...Senescence or programmed cell death is a process that interacts with many biochemical and physiological changes in living organism and is generally induced by aging. Many environmental stresses that accelerate the production of activated oxygen can also induce senescence artificially. One of the important aspects of senescence is possibly degradation of macromolecules such as DNA. It is believed that the random amplification of polymorphic DNA (RAPD) technique is a good method to compare the DNA quality of juvenile and senescence samples in which oxidative stress is induced. In this study, juvenile, senescence and plant paraquat treated leaves from tomato, tobacco and rose, as well as juvenile and senescence human tissues were processed for DNA extraction followed by RAPD technique. We discovered that plant and human genomes are influenced by senescence and environmental stresses underwent genome diversity. Using some molecular markers proved that senescence and oxidative treated samples show different DNA pattern compare to the juvenile-un- treated samples. We also concluded that RAPD technique can be used as a useful tool in genomics study to provide researchers reliable information of DNA quality and can effectively help to resolve the environment condition.展开更多
Background: The molecular interactions of hepatitis C virus (HCV) with hepatic tissue have yet to be completely elucidated and understood. The purpose of this study was to compare differential gene expression patterns...Background: The molecular interactions of hepatitis C virus (HCV) with hepatic tissue have yet to be completely elucidated and understood. The purpose of this study was to compare differential gene expression patterns in the livers of non-transgenic and transgenic mouse model expressing HCV structural proteins Core, Envelope 1 (E1) and Envelope 2 (E2) using complementary DNA (cDNA) microarrays. Results: Total RNA extracted from the livers of HCV transgenic and non-transgenic mice was analyzed with cDNA microarray and differentially expressed genes confirmed by real-time RT-PCR. Relative expression ratios of individual genes were determined by comparing hybridization of Cy5-labelled cDNA from transgenic mouse livers and Cy3-labelled cDNA from non-transgenic mouse livers. The spot array images were quantified using QuantArray software and the outlier spots was normalized and filtered using five different criteria. 15,297 genes were analyzed using three different analytical methods. Depending on these methods, twenty-one genes were found to be differentially expressed at a statistically significant level. From these, 6 genes had a consistent differential expression. Several genes were directly involved in lipid metabolism and lipid β-oxidation. 5-azacytidine induced gene 2 (AZ2), which is involved in the methylation of genes was down regulated in HCV transgenic mice. Altered transcript levels of these 6 genes were confirmed by real-time RT-PCR analysis. Conclusion: Interactions between HCV and hepatocytes not only involve lipid metabolism and redox balance, but this interaction may also influence DNA methylation, indicating a potential association with the development of hepatocellular carcinoma.展开更多
文摘Extreme ground behaviour in high-stress rock masses such as rockburst prone and squeezing ground conditions are encountered in a range of underground projects both in civil and mining applications.The occurrence of such ground behaviour types are difficult to predict and special design and construction measures must be taken to control them.Determining the most appropriate support system in such grounds is one of the major challenges for ground control engineers because there are many contributing factors to be considered,such as the rock mass parameters,the stress condition,the type and performance of the support systems,the condition of major geological structures and the size and geometry of the underground excavation.The main characteristics and support requirements of rockburst-prone and squeezing ground conditions are herein critically reviewed and characteristics of support functions are discussed.Different types of energy-absorbing rockbolts and other support elements applicable for ground support in burst-prone and squeezing grounds are introduced.Important differences in the choice and economics of ground support strategies in high-stress ground conditions between civil tunnels and mining excavations are discussed.Ground support benchmarking data and mitigation measures for mines and civil tunnels in burst-prone,squeezing and heavily swelling grounds conditions are briefly presented by some examples in practice.
基金funding organisations, Curtin International Postgraduate Scholarship (CIPRS)/Department of Mining and Metallurgy Scholarship, and the Mining Education Australia (MEA), Collaborative Research Grant Scheme [grant number RS-59041]
文摘Rockbolt is widely employed all over the world as an effective ground reinforcement element in order to secure the underground workplaces.Ordinary encapsulated rebar or rebar rockbolt is most popular and commonly used as reinforcement in a ground support system because of its accessibility,cost effectiveness and easy practicability.Reinforcement elements in a seismic condition such as rock burst have to dissipate the energy release of the dynamic impact via their deformation and ultimate load capacity,knowing that the former is more important.In other words,achieving early stiff behaviour along with large deformation capacity in rockbolts are the goals for new development in rock reinforcement.Yielding rockbolts are expensive while some of them have large deformation capability with low ultimate load capacity.In this paper,modifications were made on encapsulation of rebar rockbolts to utilise it effectively as a yielding reinforcement in seismic conditions.Applying a sufficient decoupled length in the shank of rebar rockbolts which industry has regularly been using to control the bulking of the stress fractured ground,improves the deformation capacity of the bolt.Additionally,leaving a collar bonding underneath of the bearing pad and plate removes the weaknesses of the head anchorage of rockbolt.Therefore the dynamic performance of the bolt is improved by these easily applicable modifications.The behaviour and performance of encapsulated rockbolts have been discussed first,then the effects of modifications are illustrated.The proposed modification of the rebars is not only cost effective but also easy to apply in the field and improves the performance of reinforcements in seismic prone zones.
基金Supported by Iran National Science Foundation(Grant No.91002993)
文摘Objective: To compare the bone mass density in chronic hepatitis patients before and after interferon-a treatment.Methods: A total of 70 patients with chronic hepatitis C were treated with interferon-a and were evaluated. The treatment dosage was three million IU three times a week for one year. All the patients underwent bone mass density detection at lumbar spine and femoral neck before and after the interferon-a treatment. All the necessary information such as age,sex, and laboratory test, history of occurrence of fractures, lifestyle, and menopause status was collected by interviewers face-to-face from participants at the research visit. Smoking was categorized by whether participants were nonsmokers or smokers. Menopause was designated if there had been complete cessation of menses for more than 12 months. All statistical analyses were performed by SPSS version 14(SPSS, Inc., Chicago, IL, USA).Results: Among 70 patients, 52% were male, 48% were female and the mean age was(57.0 ± 9.6) years(range: 24–79). Twenty-nine percent of the patients had a history of smoking. The mean body mass index was(24.4 ± 3.6) kg/m^2(range: 18.4–35.3). Of the70 cases, 21 had high fibrosis-4. The prevalence of overall fracture history was 2.9%(two patients).Conclusions: Chronic hepatitis C virus infection did increase the risk of development of metabolic bone disease in this cohort. Indeed, greater reduction of bone mass density occurs in advanced liver fibrosis. The bone loss in earlier stages of chronic hepatitis C infection is likely to result from increased bone reduction rather than decreased bone formation. Overall, these observations suggest an important role for chronic hepatitis C virus infection in increased bone turnover in osteodystrophy pathogenesis.
基金Supported by a grant from Iran National Science Foundation under the grant number 91002993
文摘Objective: To develop a gold nanoparticles complex conjugated with interferon-gamma(IFN-g) and methionine along with application of hyperthermia using near-infrared laser beams for the treatment of cancer cells.Methods: Gold nanorods(10 nm) were conjugated with IFN-g and methionine using carbodiimide family and characterized after purification by dialysis bags. Breast cancer cells were cultured and incubated with gold nanorods at different concentrations followed by irradiation with near-infrared laser beam. Samples were then evaluated for their viability in order to determine the effect of treatment and variables by MTT assy.Results: Zetasizer results confirmed the conjugation of gold nanorods with methionine and IFN-g. The median percentage of cell viability in 0.30 mg/m L concentration of gold nanorods was 82%. The cell viability reached to 85% at the same concentration of gold nanorods, which existed in the assayed complex. The results of MTT assay showed that the 0.60 mg/m L concentration of gold nanoparticles complex was toxic on tumor cells(P < 0.05). After exposure to hyperthermia, the viability of cells at 6 min decreased to77% in 0.30 mg/m L concentration of gold nanorods complex.Conclusions: The size and concentration of gold nanorods was not cytotoxic. However,their presence during irradiation near-infrared laser increased the number of dead cells during the treatment of cells.
文摘Senescence or programmed cell death is a process that interacts with many biochemical and physiological changes in living organism and is generally induced by aging. Many environmental stresses that accelerate the production of activated oxygen can also induce senescence artificially. One of the important aspects of senescence is possibly degradation of macromolecules such as DNA. It is believed that the random amplification of polymorphic DNA (RAPD) technique is a good method to compare the DNA quality of juvenile and senescence samples in which oxidative stress is induced. In this study, juvenile, senescence and plant paraquat treated leaves from tomato, tobacco and rose, as well as juvenile and senescence human tissues were processed for DNA extraction followed by RAPD technique. We discovered that plant and human genomes are influenced by senescence and environmental stresses underwent genome diversity. Using some molecular markers proved that senescence and oxidative treated samples show different DNA pattern compare to the juvenile-un- treated samples. We also concluded that RAPD technique can be used as a useful tool in genomics study to provide researchers reliable information of DNA quality and can effectively help to resolve the environment condition.
文摘Background: The molecular interactions of hepatitis C virus (HCV) with hepatic tissue have yet to be completely elucidated and understood. The purpose of this study was to compare differential gene expression patterns in the livers of non-transgenic and transgenic mouse model expressing HCV structural proteins Core, Envelope 1 (E1) and Envelope 2 (E2) using complementary DNA (cDNA) microarrays. Results: Total RNA extracted from the livers of HCV transgenic and non-transgenic mice was analyzed with cDNA microarray and differentially expressed genes confirmed by real-time RT-PCR. Relative expression ratios of individual genes were determined by comparing hybridization of Cy5-labelled cDNA from transgenic mouse livers and Cy3-labelled cDNA from non-transgenic mouse livers. The spot array images were quantified using QuantArray software and the outlier spots was normalized and filtered using five different criteria. 15,297 genes were analyzed using three different analytical methods. Depending on these methods, twenty-one genes were found to be differentially expressed at a statistically significant level. From these, 6 genes had a consistent differential expression. Several genes were directly involved in lipid metabolism and lipid β-oxidation. 5-azacytidine induced gene 2 (AZ2), which is involved in the methylation of genes was down regulated in HCV transgenic mice. Altered transcript levels of these 6 genes were confirmed by real-time RT-PCR analysis. Conclusion: Interactions between HCV and hepatocytes not only involve lipid metabolism and redox balance, but this interaction may also influence DNA methylation, indicating a potential association with the development of hepatocellular carcinoma.
