The deformation and failure of mining slopes in layered rocks predominantly result from shear landslides.However,the instability process of the Pusa rock avalanche in Guizhou,China,revealed a unique damage phenomenon:...The deformation and failure of mining slopes in layered rocks predominantly result from shear landslides.However,the instability process of the Pusa rock avalanche in Guizhou,China,revealed a unique damage phenomenon:prominent breaking and toppling of rock blocks occurred in the central section of the mountain,with a lack of commonly observed shear landslide features.This paper aims to investigate the underlying reasons behind this distinctive damage pattern.The study employs various methods including geological survey,UAV aerial survey,physical simulation,and discrete element numerical simulation.The findings indicate that the geological conditions,characterized by a hard upper layer and a soft lower layer along with underground mining activities,play a significant role in triggering the landslide.Furthermore,the presence of a columnar structured rock mass emerges as the primary factor influencing the instability of the Pusa rock avalanche.To elucidate the mining failure mechanism of the rock mass with vertical joints,we propose a"subsidence-buckling"failure model.Following the subsidence and collapse of the roof rock mass in the goaf,the columnar rock mass in the upper and middle portions of the slope undergoes deflection and deformation,forming a three-hinged arch structure.This structural configuration converts the pressure exerted by the overlying rock mass into both vertical pressure and lateral thrust.Under the influence of external loads,the slope experiences buckling failure,ultimately leading to instability upon fragmentation.By shedding light on these findings,this study contributes to a better understanding of the spatiotemporal evolution of mining slope fractures and their impact on slope stability.展开更多
The phase transition of titanium alloys is sensitive to the heat-treatment procedure,accompanied with the latent heat induced by phase transition.However,the latent heat during phase transition of titanium alloy has n...The phase transition of titanium alloys is sensitive to the heat-treatment procedure,accompanied with the latent heat induced by phase transition.However,the latent heat during phase transition of titanium alloy has not been systematically studied,which may result in the gap between designed and actual temperature of the sample and affect the final mechanical properties.In this work,DSC(differential scanning calorimetry)and first-principles simulate methods were used to study theβ→αphase transition process of TB18(Ti–Al-Mo-V-Cr-Nb-Fe system)metastableβtitanium alloy,especially to reveal the influence of the heating rate on latent heat.The ratio of latent heat to endothermic heat of the sample during temperature rising was introduced to interpret the effect of latent heat to actual temperature.The ratio of latent heat to endothermic heat at 1℃/min is about 15 to 20 times higher than that at 10℃/min.The higher ratio indicates that the latent heat of phase transition has a more significant effect on the temperature,which is related to the temperature range of phase transition and theαvolume fraction.Compared with the heating rate of 1℃/min,theβ→αphase transition takes place at higher temperature and the volume fraction ofαis smaller at 10℃/min.Meanwhile,there is a precipitation free zone between grain boundaryαand intragranularαand the distribution ofαlamellae is heterogeneous when the heating rate is 10℃/min.Both of the experimental and theoretical results suggest that the latent heat of phase transition is the main cause of the temperature fluctuation during heat-treatment process.This work has guiding significance for microstructure optimization affected by temperature,to achieve the desired mechanical properties.展开更多
This study investigated the expression of lung surfactant proteins (SP-B and SP-C),and regulatory factors [forkhead box A2(FOXA2)and nitrolyogenic FOXA2 (N-FOXA2)]in the fetal lung of rats with gestational diabetes me...This study investigated the expression of lung surfactant proteins (SP-B and SP-C),and regulatory factors [forkhead box A2(FOXA2)and nitrolyogenic FOXA2 (N-FOXA2)]in the fetal lung of rats with gestational diabetes mellitus (GDM)in order to study the mechanism of pulmonary dysplasia.The rat GDM model was established by using streptozotocin intraperitoneally in the first stage of pregnancy.There were 10 rats in the GDM group,and 10 healthy rats in normal control group without any treatment.Fetal lungs of two groups were taken at day 21 of pregnancy.Blood glucose levels of maternal rats and fetal rats were measured by Roche blood glucose meter.The histological changes in the fetal lung were observed under the light microscope in both groups.The SP-B,SP-C and FOXA2were determined in the fetal lung of two groups immunohistochemically. The expression levels of SP-B,SP-C,total FOXA2,FOXA2 in nucleus (n-FOXA2), N-FOXA2 proteins were detected by Western blotting,and the relative expression levels of SP-B,SP-C,FOXA2 mRNA in the fetal lung of two groups were detected by RT-PCR.The results showed that blood glucose levels of maternal rats and fetal rats in GDM group were higher than those in control group.The light microscope revealed fetal lung development retardation in GDM group.The expression of SP-B and SP-C in GDM group was significantly reduced as compared with control group (P<0.05).As compared with control group,the n-FOXA2 expression was significantly decreased in the fetal lung tissue,and N-FOXA2 was significantly increased in control group (P<0.05),but there was no significant changes in the total FOXA2(P>0.05).It was concluded that GDM can cause fetal lung development and maturation disorders,and FOXA2 in fetal lung tissue decreases while nitrocellulose FOXA2 increases.展开更多
In recent years,the ecological environment along highways in Tibetan Plateau has been severely affected due to the rapid construction of highways.In order to solve the problems of multiple indicators and inconsistent ...In recent years,the ecological environment along highways in Tibetan Plateau has been severely affected due to the rapid construction of highways.In order to solve the problems of multiple indicators and inconsistent criteria in the ecological impact assessment of highways,and to scientifically screen assessment indicators,the paper proposes a multi-round indicator screening method,which combines literature analysis,expert rating,and statistical analysis.Based on this screening method,normalized difference vegetation index,land surface temperature,elevation,and normalized difference soil index are screened out.Combined with multiple linear regression,an ecological impact assessment model is established and applied to ecological impact assessment of Gonghe-Yushu Expressway.The results show that the expressway construction is the first driving force for the deterioration of the ecological environment along the roadside,and its interference range on the desert grassland ecosystem is greater than that on the agroforestry system.The ecological environment within 150 m on both sides of the expressway should be protected.展开更多
Background Glycoprotein non-metastatic melanoma protein B （GPNMB） plays an important role in the pathogenesis of inflammatory and malignant diseases. We investigated the expression of GPNMB in benign and malignant s...Background Glycoprotein non-metastatic melanoma protein B （GPNMB） plays an important role in the pathogenesis of inflammatory and malignant diseases. We investigated the expression of GPNMB in benign and malignant skin diseases. Methods Tissue microarray was performed in the skin tissues of 102 cases including malignant melanoma （MM）, squamous cell carcinoma （SCC）, basal cell carcinoma （BCC）, and benign dermatosis. The expression of GPNMB in the tissues was detected by immunohistochemistry. Twenty cases of normal skin and adjacent neoplastic normal skin tissues were selected as controls. Results GPNMB was positively stained in skin malignancies （38/50, 76%）, which was significantly higher than that in the control and the benign skin tissues （P=0.001 and 〈0.001 respectively）. GPNMB was positively stained in MM （13/15, 87%） and SCC （16/20, 80%） （P 〈0.001）. Significant higher expression of GPNMB was observed in patients aged 〉65 years than those less than 65 years （n=11 and n=9 respectively, P=0.027）. No significant difference of the expression rates was observed between normal control and BCC; however, stronger intensity was detected in the latter. Negative or weak expression was observed in the controls. Conclusion Over-expression of GPNMB correlated strongly and might play an important role in the pathogenesis of MM and SCC.展开更多
The hydrogen absorption kinetics of TA15 titanium alloy at 973-1123 K was studied using a tube-type hydrogen treatment furnace. The hydrogen absorption kinetic curves obtained were analyzed according to a series of me...The hydrogen absorption kinetics of TA15 titanium alloy at 973-1123 K was studied using a tube-type hydrogen treatment furnace. The hydrogen absorption kinetic curves obtained were analyzed according to a series of mechanism equations to reveal the kinetic parameters and mechanism of the hydrogen absorption process. The results show that both the hydrogen absorption rate and the equilibrium hydrogen pressure increase and the time to reach equilibrium is shortened with increasing temperature. It is found that only the second hydrogen absorption period exists in the hydrogen absorption process of TA15 alloy between 973 and 1123 K, and the activation energy is 54.889 kJ/mol for hydrogen absorption. X-ray diffraction （XRD） and scanning electron microscopy （SEM） results demonstrate that δ hydride forms between 973 and 1123 K, and β phase decreases with the increase of temperature. Orthorhombic α＂ martensite is generated at 1073-1123 K, and their amount increases with increasing temperature.展开更多
A case of hereditary benign telangiectasia without family history was reported. A 39-year-old woman presented with small and tiny telangiectases on the face, neck, upper trunk and forearms at birth. The numbers and si...A case of hereditary benign telangiectasia without family history was reported. A 39-year-old woman presented with small and tiny telangiectases on the face, neck, upper trunk and forearms at birth. The numbers and sizes of the lesions increased gradually and she had no hemorrhagic diathesis and systemic diseases. No similar patients were found in her family. Upon physical examination, telangiectases were found on the face, neck, upper trunk and forearms; and a telangiectatic erythema was found on the right forearm 25 mm ×40 mm in size. Histopathology examination showed a normal epidermis and dilation of the capillaries at upper dermis. Hereditary benign telangiectasia without family history was diagnosed.展开更多
基金funded by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2022Z001)National Natural Science Foundation of China(Grant No.41877273)+3 种基金Science and Technology Plan Project of Sichuan Province(Grant No.2021YJ0053)Sichuan Natural Science Foundation(Grant No.2022NSFSC1176)Innovative Research Groups of the National Natural Science Foundation of China(Grant No.41521002)POWERCHINA Science and technology project(Grant No.DJ-ZDXM-2020-03)。
文摘The deformation and failure of mining slopes in layered rocks predominantly result from shear landslides.However,the instability process of the Pusa rock avalanche in Guizhou,China,revealed a unique damage phenomenon:prominent breaking and toppling of rock blocks occurred in the central section of the mountain,with a lack of commonly observed shear landslide features.This paper aims to investigate the underlying reasons behind this distinctive damage pattern.The study employs various methods including geological survey,UAV aerial survey,physical simulation,and discrete element numerical simulation.The findings indicate that the geological conditions,characterized by a hard upper layer and a soft lower layer along with underground mining activities,play a significant role in triggering the landslide.Furthermore,the presence of a columnar structured rock mass emerges as the primary factor influencing the instability of the Pusa rock avalanche.To elucidate the mining failure mechanism of the rock mass with vertical joints,we propose a"subsidence-buckling"failure model.Following the subsidence and collapse of the roof rock mass in the goaf,the columnar rock mass in the upper and middle portions of the slope undergoes deflection and deformation,forming a three-hinged arch structure.This structural configuration converts the pressure exerted by the overlying rock mass into both vertical pressure and lateral thrust.Under the influence of external loads,the slope experiences buckling failure,ultimately leading to instability upon fragmentation.By shedding light on these findings,this study contributes to a better understanding of the spatiotemporal evolution of mining slope fractures and their impact on slope stability.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA22010101)the National Key Research and Development Program of China(2021YFC2801801)+1 种基金the CAS Project for Young Scientists in Basic Research(YSBR-025),the Natural Science Foundation of China(51871225)the Youth Innovation Promotion Association CAS and Liaoning Revitalization Talents Program(XLYC1907005).
文摘The phase transition of titanium alloys is sensitive to the heat-treatment procedure,accompanied with the latent heat induced by phase transition.However,the latent heat during phase transition of titanium alloy has not been systematically studied,which may result in the gap between designed and actual temperature of the sample and affect the final mechanical properties.In this work,DSC(differential scanning calorimetry)and first-principles simulate methods were used to study theβ→αphase transition process of TB18(Ti–Al-Mo-V-Cr-Nb-Fe system)metastableβtitanium alloy,especially to reveal the influence of the heating rate on latent heat.The ratio of latent heat to endothermic heat of the sample during temperature rising was introduced to interpret the effect of latent heat to actual temperature.The ratio of latent heat to endothermic heat at 1℃/min is about 15 to 20 times higher than that at 10℃/min.The higher ratio indicates that the latent heat of phase transition has a more significant effect on the temperature,which is related to the temperature range of phase transition and theαvolume fraction.Compared with the heating rate of 1℃/min,theβ→αphase transition takes place at higher temperature and the volume fraction ofαis smaller at 10℃/min.Meanwhile,there is a precipitation free zone between grain boundaryαand intragranularαand the distribution ofαlamellae is heterogeneous when the heating rate is 10℃/min.Both of the experimental and theoretical results suggest that the latent heat of phase transition is the main cause of the temperature fluctuation during heat-treatment process.This work has guiding significance for microstructure optimization affected by temperature,to achieve the desired mechanical properties.
基金This work was supported by grants from the National Natural Science Foundation of China (No.30971072) and the Natural Science Foundation of Hubei Province (No.2017CFB749).
文摘This study investigated the expression of lung surfactant proteins (SP-B and SP-C),and regulatory factors [forkhead box A2(FOXA2)and nitrolyogenic FOXA2 (N-FOXA2)]in the fetal lung of rats with gestational diabetes mellitus (GDM)in order to study the mechanism of pulmonary dysplasia.The rat GDM model was established by using streptozotocin intraperitoneally in the first stage of pregnancy.There were 10 rats in the GDM group,and 10 healthy rats in normal control group without any treatment.Fetal lungs of two groups were taken at day 21 of pregnancy.Blood glucose levels of maternal rats and fetal rats were measured by Roche blood glucose meter.The histological changes in the fetal lung were observed under the light microscope in both groups.The SP-B,SP-C and FOXA2were determined in the fetal lung of two groups immunohistochemically. The expression levels of SP-B,SP-C,total FOXA2,FOXA2 in nucleus (n-FOXA2), N-FOXA2 proteins were detected by Western blotting,and the relative expression levels of SP-B,SP-C,FOXA2 mRNA in the fetal lung of two groups were detected by RT-PCR.The results showed that blood glucose levels of maternal rats and fetal rats in GDM group were higher than those in control group.The light microscope revealed fetal lung development retardation in GDM group.The expression of SP-B and SP-C in GDM group was significantly reduced as compared with control group (P<0.05).As compared with control group,the n-FOXA2 expression was significantly decreased in the fetal lung tissue,and N-FOXA2 was significantly increased in control group (P<0.05),but there was no significant changes in the total FOXA2(P>0.05).It was concluded that GDM can cause fetal lung development and maturation disorders,and FOXA2 in fetal lung tissue decreases while nitrocellulose FOXA2 increases.
基金supported by the National Natural Science Foundation of China(NSFC)(No.41801387)。
文摘In recent years,the ecological environment along highways in Tibetan Plateau has been severely affected due to the rapid construction of highways.In order to solve the problems of multiple indicators and inconsistent criteria in the ecological impact assessment of highways,and to scientifically screen assessment indicators,the paper proposes a multi-round indicator screening method,which combines literature analysis,expert rating,and statistical analysis.Based on this screening method,normalized difference vegetation index,land surface temperature,elevation,and normalized difference soil index are screened out.Combined with multiple linear regression,an ecological impact assessment model is established and applied to ecological impact assessment of Gonghe-Yushu Expressway.The results show that the expressway construction is the first driving force for the deterioration of the ecological environment along the roadside,and its interference range on the desert grassland ecosystem is greater than that on the agroforestry system.The ecological environment within 150 m on both sides of the expressway should be protected.
文摘Background Glycoprotein non-metastatic melanoma protein B （GPNMB） plays an important role in the pathogenesis of inflammatory and malignant diseases. We investigated the expression of GPNMB in benign and malignant skin diseases. Methods Tissue microarray was performed in the skin tissues of 102 cases including malignant melanoma （MM）, squamous cell carcinoma （SCC）, basal cell carcinoma （BCC）, and benign dermatosis. The expression of GPNMB in the tissues was detected by immunohistochemistry. Twenty cases of normal skin and adjacent neoplastic normal skin tissues were selected as controls. Results GPNMB was positively stained in skin malignancies （38/50, 76%）, which was significantly higher than that in the control and the benign skin tissues （P=0.001 and 〈0.001 respectively）. GPNMB was positively stained in MM （13/15, 87%） and SCC （16/20, 80%） （P 〈0.001）. Significant higher expression of GPNMB was observed in patients aged 〉65 years than those less than 65 years （n=11 and n=9 respectively, P=0.027）. No significant difference of the expression rates was observed between normal control and BCC; however, stronger intensity was detected in the latter. Negative or weak expression was observed in the controls. Conclusion Over-expression of GPNMB correlated strongly and might play an important role in the pathogenesis of MM and SCC.
基金supported by the Major State Basic Research and Development Program of China (No.11AZ6305)
文摘The hydrogen absorption kinetics of TA15 titanium alloy at 973-1123 K was studied using a tube-type hydrogen treatment furnace. The hydrogen absorption kinetic curves obtained were analyzed according to a series of mechanism equations to reveal the kinetic parameters and mechanism of the hydrogen absorption process. The results show that both the hydrogen absorption rate and the equilibrium hydrogen pressure increase and the time to reach equilibrium is shortened with increasing temperature. It is found that only the second hydrogen absorption period exists in the hydrogen absorption process of TA15 alloy between 973 and 1123 K, and the activation energy is 54.889 kJ/mol for hydrogen absorption. X-ray diffraction （XRD） and scanning electron microscopy （SEM） results demonstrate that δ hydride forms between 973 and 1123 K, and β phase decreases with the increase of temperature. Orthorhombic α＂ martensite is generated at 1073-1123 K, and their amount increases with increasing temperature.
文摘A case of hereditary benign telangiectasia without family history was reported. A 39-year-old woman presented with small and tiny telangiectases on the face, neck, upper trunk and forearms at birth. The numbers and sizes of the lesions increased gradually and she had no hemorrhagic diathesis and systemic diseases. No similar patients were found in her family. Upon physical examination, telangiectases were found on the face, neck, upper trunk and forearms; and a telangiectatic erythema was found on the right forearm 25 mm ×40 mm in size. Histopathology examination showed a normal epidermis and dilation of the capillaries at upper dermis. Hereditary benign telangiectasia without family history was diagnosed.
