Selective hydrogenation of C=C and C=O bonds in cinnamaldehyde(CAL)to produce desired products is a challenging task due to the complex conjugate system of the two unsaturated functional groups.In this study,a simple ...Selective hydrogenation of C=C and C=O bonds in cinnamaldehyde(CAL)to produce desired products is a challenging task due to the complex conjugate system of the two unsaturated functional groups.In this study,a simple ball milling method is presented for synthesizing Pt-based single-atom alloy catalysts(SAAs)that can function as a control switch for the selective hydrogenation of CAL into highly valuable products.展开更多
Alstonia scholaris(L.)R.Br.,an evergreen tropical plant rich in indole alkaloids with significant physiological activity,is traditionally used to treat respiratory diseases in China.This study was conducted to establi...Alstonia scholaris(L.)R.Br.,an evergreen tropical plant rich in indole alkaloids with significant physiological activity,is traditionally used to treat respiratory diseases in China.This study was conducted to establish the toxicity profile of the alkaloid extract(TA)of A.scholaris leaves in non-rodents.After oral administration of a single dose(4 g/kg.bw),a num-ber of transient symptoms,such as unsteady gait,drooling,emesis,and reddening of peri-oral mucosa,were observed,but no treatment-related mortality.A sub-chronic toxicity study with a range of doses of TA(20,60 and 120 mg/kg.bw)was conducted for a 13-week treatment period,followed by 4-week recovery observation.Except for emesis and drooling in majority of animals in 120 mg/kg.bw treatment group,no clinical changes were observed in TA-treated animals.Data from electrocardiography,bone marrow,urine,fecal,hematology and clinical chemistry analyses were comparable between TA-treated and control animals.No significant differences in the relative organ weights and histopathological characteristics were evident between the TA-treated and control groups.Accordingly,the non-observed-adverse-effect-level(NOAEL)of TA was established as 120 mg/kg.bw.Our results add further knowledge to the safety database for indole alkaloid extracts from A.scholaris with potential utility as novel drug candidates.展开更多
Alstonia scholaris(L.)R.Br.(Apocynaceae)is an evergreen tree that has been used to treat lung diseases.In this study,the toxicity profile of indole alkaloids from leaves of A.scholaris was investigated.In acute toxici...Alstonia scholaris(L.)R.Br.(Apocynaceae)is an evergreen tree that has been used to treat lung diseases.In this study,the toxicity profile of indole alkaloids from leaves of A.scholaris was investigated.In acute toxicity tests,mice were adminis-tered total alkaloids(TA)and five indole alkaloids.In a chronic toxicity test,rats were continuously administered TA(50,100,and 300 mg/kg bw)for 13 weeks,followed by a 4-week recovery.A single administration of TA affected the behavior of mice,and at 12.8 g/kg bw,prone position,shortness of breath,wheezing,and convulsion were observed.The half-lethal dose(LD50)in mice was 5.48 g/kg bw,almost 2740 times the clinical dose in humans.Among the five indole alkaloids,the maximum tolerance dose in mice ranged from 0.75 to 4 g/kg bw.The TA-treated rats did not die and showed no adverse effects or dose-dependent changes in weight or food and water consumption,despite fluctuations in hematological and bio-chemical parameters compared with historical data.Furthermore,both gross and histopathological observations revealed no abnormalities in any organ.With daily oral administration to rats,the non-observed-adverse-effect-level of TA was 100 mg/kg bw.The results indicate that TA is safe for clinical use.展开更多
For a reversed magnetic shear plasma formed by early neutral beam injection into the HL-2A tokamak,magnetohydrodynamics instability analysis against ideal low-n modes and resistive interchange modes is carried out.Low...For a reversed magnetic shear plasma formed by early neutral beam injection into the HL-2A tokamak,magnetohydrodynamics instability analysis against ideal low-n modes and resistive interchange modes is carried out.Low-n modes located in the low shear region around the shear reversal point are driven unstably by large pressure gradient,and they are of the characteristics of infernal modes.High pressure in the central negative shear region drives resistive interchange modes with the unstable window extending to r/a≈0.2,but not covering the low shear region around the shear reversal point.展开更多
Objective:To explore the effect of Chlamydia pneumoniae on the lipid metabolism of mononuclear macrophages in patients with carotid atherosclerotic plaque.Methods: A total of 90 patients with carotid atherosclerosis w...Objective:To explore the effect of Chlamydia pneumoniae on the lipid metabolism of mononuclear macrophages in patients with carotid atherosclerotic plaque.Methods: A total of 90 patients with carotid atherosclerosis who were admitted in our hospital from January, 2012 to December, 2013 were included in the study and served as the observation group, while 72 aged individuals at the same stage for physical examination were served as the control group. The plaque formation in the two groups was observed and compared. The levels of TC, LDL-C, and HDL-C in the two groups were detected and compared. ELISA was used to detect CP IgG. The positive rate of CP IgG in the two groups was compared.Results: The multiple plaque, soft plaque, and mixed plaque in the observation group were significantly greater than those in the control group, but the comparison of hard plaque between the two groups was not statistically significant. The levels of TC and LDL-C in the observation group were significantly higher than those in the control group, while HDL-C level was significantly lower than that in the control group. The positive rate of CP IgG in the observation group was significantly higher than that in the control group.Conclusions: Chlamydia pneumoniae has an important effect on the lipid metabolism of mononuclear macrophages in patients with carotid atherosclerotic plaque.展开更多
The self-consistent poloidal flow shear induced by turbulence driven by impurity radiation has been studied analytically. A set of reduced equations is obtained. In our system, three equilibrium states exist. The firs...The self-consistent poloidal flow shear induced by turbulence driven by impurity radiation has been studied analytically. A set of reduced equations is obtained. In our system, three equilibrium states exist. The first is the zero flow shear state, which is relevant to the behavior such as L mode, the second is the positive flow shear state, which is relevant to the behavior such as dithering H mode, and the third is the negative flow shear state, which is relevant to the behavior such as edge-localized modes.展开更多
Starting from the four-Huid equation which can simply and effectively describe the motion of trapped particles,we derive the eigenmode equations and the dispersion relation for m=1 internal kink mode with the effects ...Starting from the four-Huid equation which can simply and effectively describe the motion of trapped particles,we derive the eigenmode equations and the dispersion relation for m=1 internal kink mode with the effects of trapped particles,diamagnetic drifts,finite resistivity and anomalous electron viscosity included.Then,using those results,we Gnd the trapped particles effects have substantial influence on m=l internal kink mode in the cases with and without high-energy alpha particles in the core plasma.展开更多
Indole alkaloids extract(IAAS)was prepared from leaves of Alstonia scholaris(L.)R.Br.,an evergreen tropical plant widely distributed throughout the world.This plant has been used historically by the Dai ethnic people ...Indole alkaloids extract(IAAS)was prepared from leaves of Alstonia scholaris(L.)R.Br.,an evergreen tropical plant widely distributed throughout the world.This plant has been used historically by the Dai ethnic people of China to treat respiratory diseases.This study evaluated the genotoxicity and safety pharmacology of IAAS to support clinical use.The bacterial reverse mutation(Ames)test,in vitro mammalian chromosomal aberration test,and in vivo mammalian erythrocyte micronucleus(MN)test were performed to evaluate genotoxicity.Mice were administered IAAS(240,480,or 960 mg/kg bw)once orally to observe adverse central nervous system effects.Furthermore,beagle dogs were administered IAAS(10,30,60 mg/kg bw)once via the duodenum to evaluate its effects on the cardiovascular and respiratory systems.IAAS with or without S9-induced metabolic activation showed no genotoxicity in the Ames test up to 500μg/plate,in the mammalian chromosomal aberration test up to 710μg/mL,or in the MN test up to 800 mg/kg bw.No abnormal neurobehavioral effects were observed in mice following treatment with up to 960 mg/kg bw of IAAS.Moreover,blood pressure,heart rate,electrocardiogram parameters,and depth and rate of breathing in anesthetized beagle dogs did not differ among the IAAS doses or from the vehicle group.These data indicated that IAAS did not induce mutagenicity,clastogenicity,or genotoxicity,and no pharmaco-toxicological effects were observed in the respiratory,cardiovascular,or central nervous systems.Our results increased understanding of safety considerations associated with IAAS,and may indicate that IAAS is a possible drug candidate.展开更多
Screw failure is one of the main scrap forms for rear axle tube, and thread turning after surfacing is a common means of remanufacturing. This paper takes rear axle tube as the main research topic, which is made of 40...Screw failure is one of the main scrap forms for rear axle tube, and thread turning after surfacing is a common means of remanufacturing. This paper takes rear axle tube as the main research topic, which is made of 40Mn and provided by an axle company. Manual electric arc welding, CO2 shielded arc welding and argon shielded arc welding are carried to overlay the damaged thread. The deposited metal consists of two welding material lays. Welding process and overlay properties are characterized by the test and analysis of microstructure, residual stress and hardness of surfacing layers. The results show that argon shielded arc welding is an effective method to repair the failure thread; its microstructure of fusion area is meticulous and uniform; its residual compressive stress （absolute value） of welding surface is the biggest among the three welding methods; its hardness curve is relatively fiat and appropriate for turning.展开更多
基金financially supported by the National key Research and Development Program Nanotechnology Specific Project(No.2020YFA0210900)the Science and Technology Key Project of Guangdong Province,China(No.2020B010188002)+6 种基金Guangdong Natural Science Funds for Distinguished Young Scholar(No.2022B1515020035)Guangdong Provincial Key R&D Programme(No.2019B110206002)the National Natural Science Foundation of China(Nos.22078371,21938001 and 21961160741)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT0IC102)the NSF of Guangdong Province(No.2020A1515011141)the Science and Technology Project of Guangzhou City,China(No.202102020461)Special funding for"Guangxi Bagui Scholars"。
文摘Selective hydrogenation of C=C and C=O bonds in cinnamaldehyde(CAL)to produce desired products is a challenging task due to the complex conjugate system of the two unsaturated functional groups.In this study,a simple ball milling method is presented for synthesizing Pt-based single-atom alloy catalysts(SAAs)that can function as a control switch for the selective hydrogenation of CAL into highly valuable products.
基金The authors are grateful to Yunnan Major Science and Technology Project(2019ZF003,2019FY003004)the National Key Research and Development Program of China(2017YFC1704007)the general program of applied basic research of Yunnan province(2019FB116)for partial financial support.
文摘Alstonia scholaris(L.)R.Br.,an evergreen tropical plant rich in indole alkaloids with significant physiological activity,is traditionally used to treat respiratory diseases in China.This study was conducted to establish the toxicity profile of the alkaloid extract(TA)of A.scholaris leaves in non-rodents.After oral administration of a single dose(4 g/kg.bw),a num-ber of transient symptoms,such as unsteady gait,drooling,emesis,and reddening of peri-oral mucosa,were observed,but no treatment-related mortality.A sub-chronic toxicity study with a range of doses of TA(20,60 and 120 mg/kg.bw)was conducted for a 13-week treatment period,followed by 4-week recovery observation.Except for emesis and drooling in majority of animals in 120 mg/kg.bw treatment group,no clinical changes were observed in TA-treated animals.Data from electrocardiography,bone marrow,urine,fecal,hematology and clinical chemistry analyses were comparable between TA-treated and control animals.No significant differences in the relative organ weights and histopathological characteristics were evident between the TA-treated and control groups.Accordingly,the non-observed-adverse-effect-level(NOAEL)of TA was established as 120 mg/kg.bw.Our results add further knowledge to the safety database for indole alkaloid extracts from A.scholaris with potential utility as novel drug candidates.
基金The authors are grateful to the Yunnan Major Science and Technology Project(2019ZF003)National Key Research and Development Program of China(2017YFC1704007)for partial financial support.
文摘Alstonia scholaris(L.)R.Br.(Apocynaceae)is an evergreen tree that has been used to treat lung diseases.In this study,the toxicity profile of indole alkaloids from leaves of A.scholaris was investigated.In acute toxicity tests,mice were adminis-tered total alkaloids(TA)and five indole alkaloids.In a chronic toxicity test,rats were continuously administered TA(50,100,and 300 mg/kg bw)for 13 weeks,followed by a 4-week recovery.A single administration of TA affected the behavior of mice,and at 12.8 g/kg bw,prone position,shortness of breath,wheezing,and convulsion were observed.The half-lethal dose(LD50)in mice was 5.48 g/kg bw,almost 2740 times the clinical dose in humans.Among the five indole alkaloids,the maximum tolerance dose in mice ranged from 0.75 to 4 g/kg bw.The TA-treated rats did not die and showed no adverse effects or dose-dependent changes in weight or food and water consumption,despite fluctuations in hematological and bio-chemical parameters compared with historical data.Furthermore,both gross and histopathological observations revealed no abnormalities in any organ.With daily oral administration to rats,the non-observed-adverse-effect-level of TA was 100 mg/kg bw.The results indicate that TA is safe for clinical use.
基金Supported by the National Natural Science Foundation under Grant No.19889502.
文摘For a reversed magnetic shear plasma formed by early neutral beam injection into the HL-2A tokamak,magnetohydrodynamics instability analysis against ideal low-n modes and resistive interchange modes is carried out.Low-n modes located in the low shear region around the shear reversal point are driven unstably by large pressure gradient,and they are of the characteristics of infernal modes.High pressure in the central negative shear region drives resistive interchange modes with the unstable window extending to r/a≈0.2,but not covering the low shear region around the shear reversal point.
文摘Objective:To explore the effect of Chlamydia pneumoniae on the lipid metabolism of mononuclear macrophages in patients with carotid atherosclerotic plaque.Methods: A total of 90 patients with carotid atherosclerosis who were admitted in our hospital from January, 2012 to December, 2013 were included in the study and served as the observation group, while 72 aged individuals at the same stage for physical examination were served as the control group. The plaque formation in the two groups was observed and compared. The levels of TC, LDL-C, and HDL-C in the two groups were detected and compared. ELISA was used to detect CP IgG. The positive rate of CP IgG in the two groups was compared.Results: The multiple plaque, soft plaque, and mixed plaque in the observation group were significantly greater than those in the control group, but the comparison of hard plaque between the two groups was not statistically significant. The levels of TC and LDL-C in the observation group were significantly higher than those in the control group, while HDL-C level was significantly lower than that in the control group. The positive rate of CP IgG in the observation group was significantly higher than that in the control group.Conclusions: Chlamydia pneumoniae has an important effect on the lipid metabolism of mononuclear macrophages in patients with carotid atherosclerotic plaque.
基金Supported by the Nuclear Science Foundation in China under Grant No.J94c03031。
文摘The self-consistent poloidal flow shear induced by turbulence driven by impurity radiation has been studied analytically. A set of reduced equations is obtained. In our system, three equilibrium states exist. The first is the zero flow shear state, which is relevant to the behavior such as L mode, the second is the positive flow shear state, which is relevant to the behavior such as dithering H mode, and the third is the negative flow shear state, which is relevant to the behavior such as edge-localized modes.
文摘Starting from the four-Huid equation which can simply and effectively describe the motion of trapped particles,we derive the eigenmode equations and the dispersion relation for m=1 internal kink mode with the effects of trapped particles,diamagnetic drifts,finite resistivity and anomalous electron viscosity included.Then,using those results,we Gnd the trapped particles effects have substantial influence on m=l internal kink mode in the cases with and without high-energy alpha particles in the core plasma.
基金The authors are grateful to Yunnan Major Science and Technology Project(2019ZF003,2019FY003004)the National Key Research and Development Program of China(2017YFC1704007)the general program of applied basic research of Yunnan province(2019FB116)for partial financial support.
文摘Indole alkaloids extract(IAAS)was prepared from leaves of Alstonia scholaris(L.)R.Br.,an evergreen tropical plant widely distributed throughout the world.This plant has been used historically by the Dai ethnic people of China to treat respiratory diseases.This study evaluated the genotoxicity and safety pharmacology of IAAS to support clinical use.The bacterial reverse mutation(Ames)test,in vitro mammalian chromosomal aberration test,and in vivo mammalian erythrocyte micronucleus(MN)test were performed to evaluate genotoxicity.Mice were administered IAAS(240,480,or 960 mg/kg bw)once orally to observe adverse central nervous system effects.Furthermore,beagle dogs were administered IAAS(10,30,60 mg/kg bw)once via the duodenum to evaluate its effects on the cardiovascular and respiratory systems.IAAS with or without S9-induced metabolic activation showed no genotoxicity in the Ames test up to 500μg/plate,in the mammalian chromosomal aberration test up to 710μg/mL,or in the MN test up to 800 mg/kg bw.No abnormal neurobehavioral effects were observed in mice following treatment with up to 960 mg/kg bw of IAAS.Moreover,blood pressure,heart rate,electrocardiogram parameters,and depth and rate of breathing in anesthetized beagle dogs did not differ among the IAAS doses or from the vehicle group.These data indicated that IAAS did not induce mutagenicity,clastogenicity,or genotoxicity,and no pharmaco-toxicological effects were observed in the respiratory,cardiovascular,or central nervous systems.Our results increased understanding of safety considerations associated with IAAS,and may indicate that IAAS is a possible drug candidate.
基金supported by the National Basic Research Program of China (Grant No. 2011CB013406)
文摘Screw failure is one of the main scrap forms for rear axle tube, and thread turning after surfacing is a common means of remanufacturing. This paper takes rear axle tube as the main research topic, which is made of 40Mn and provided by an axle company. Manual electric arc welding, CO2 shielded arc welding and argon shielded arc welding are carried to overlay the damaged thread. The deposited metal consists of two welding material lays. Welding process and overlay properties are characterized by the test and analysis of microstructure, residual stress and hardness of surfacing layers. The results show that argon shielded arc welding is an effective method to repair the failure thread; its microstructure of fusion area is meticulous and uniform; its residual compressive stress （absolute value） of welding surface is the biggest among the three welding methods; its hardness curve is relatively fiat and appropriate for turning.
