Background:Mesenchymal stem cells(MSCs)have shown great potential in treating neurodegenerative diseases,incuding Parkinson's disease(PD),due to their ability to differentiate into neurons and secrete neurotrophic...Background:Mesenchymal stem cells(MSCs)have shown great potential in treating neurodegenerative diseases,incuding Parkinson's disease(PD),due to their ability to differentiate into neurons and secrete neurotrophic factors.Genetic modification of MSCs for PD treatment has become a research focus.Methods:In this study,rat pulmonary mesenchymal stem cells(PMSCs)were transduced with lentiviral vectors carrying Lmxla/NeuroDI to establish genetically engineered PMSCs(LN-PMSCs)and induce their diferentiation into dopaminergic neurons.The LN-PMSCs were then transplanted into the right medial forebrain bundle region of PD model rats prepared using the 6-Hydroxydopamine(6-OHDA)method.Four weeks post-transplantation,the survival and diferentiation of the cells in the brain and motor function of the PD rats were evaluated.Results:The results showed that after 12 days of induction,the genetically modified LN-PMSCs had differentiated into a large number of dopaminergic neurons.Four weeks post-transplantation,these cells significantly improved motor dysfunction in PD rats and promoted the expression of neuron marker TUI,dopaminergic neuron markers FOXA2 and TH,gamma-aminobutyric acid-ergic(GABAergic)neuron marker GABA,astrocyte marker GFAP,presynaptic marker SYN,and postsynaptic marker PSD95 in the transplantation area.Conclusion:Our findings suggest that the gene-engineered PMSCs cell line overexpressing Lmxla and NeuroDI(LN-PMSCs)transplantation could be a potential therapeutic strategy for treating PD.展开更多
Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation...Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainability and management of teak plantations in hilly areas.展开更多
The fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints was studied by high- frequency fatigue test and finite element （FE） methods. The fatigue test results showed that a better enhancement ...The fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints was studied by high- frequency fatigue test and finite element （FE） methods. The fatigue test results showed that a better enhancement of fatigue life was achieved for the joints with highlocked bolts by employing the combinations of cold expansion, interference fit, and clamping force. The fractography revealed that fatigue cracks propagated tortuously; more fatigue micro-cliffs, tearing ridges, lamellar structure were observed, and fatigue striation spacing was simultaneously reduced. The evaluation of residual stress conducted by FE methods confirmed the experimental results and locations of fatigue crack initiation. The extension of fatigue lives can be attributed to the evolution of fatigue damage and effect of beneficial compressive residual stresses around the hole, resulting in the delay of crack initiation, crack deflection, and plasticityinduced crack closure.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.展开更多
(1-x)LiCuNb_(3)O_(9)-Bi(Mg_(0.5)Zr_(0.5))O_(3) ceramics((1-x)LCN-xBMZ)with 0≤x≤0.08 were synthesized by a solid-state reaction method.The phase structure of(1-x)LCN-xBMZ ceramics was characterized by X ray diffracti...(1-x)LiCuNb_(3)O_(9)-Bi(Mg_(0.5)Zr_(0.5))O_(3) ceramics((1-x)LCN-xBMZ)with 0≤x≤0.08 were synthesized by a solid-state reaction method.The phase structure of(1-x)LCN-xBMZ ceramics was characterized by X ray diffraction(XRD),which revealed that the ceranics were distorted cubic perovskite structures.Apparent giant permitivity of 1.98× 10^(4)-1.05× 10^(5) at 100kHz over the measured temperature range(259℃-250℃)was observed in the sintered(1-x)LCN-xBMZ(0≤x≤0.08)ceramics.Especially for the sample of x=0.04,the temperature stability of permitivity was markedly increased(△ε/ε100℃≤±15%),and high relative permitivity(>8.3 × 10^(4))were obtained over a wide temperature range from 100℃ to 250℃at 100 kHz,which indicates that this ceramic is a promising dielectrice material for elevated temperature dielectrics.The giant dielectric property of(1-x)LCN-xBMZ ceramics are profoundly concerned with the Maxwell-Wagner effect.展开更多
基金supported by the National Natural Science Foundation of China(NSFC grant Nos.82371382,81771381)the Natural Science Foundation of the Higher Education Institutions of Anhui Province(grant Nos.KJ2021ZD0085,2022AH051434,2024AH051296 and 2024AH040193)+3 种基金the Anhui Provincial Key Research and Development Project(grantNos.2022e07020030 and 2022e07020032)the Science Research Project of BengbuMedical College(grant No.2021byfy002)the Postgraduate Innovative Training Program of BengbuMedical College(grant No.Byycx23006)the Undergraduate Innovative Training Program of China(grant Nos.202310367015,202410367002,202410367012,202410367079).
文摘Background:Mesenchymal stem cells(MSCs)have shown great potential in treating neurodegenerative diseases,incuding Parkinson's disease(PD),due to their ability to differentiate into neurons and secrete neurotrophic factors.Genetic modification of MSCs for PD treatment has become a research focus.Methods:In this study,rat pulmonary mesenchymal stem cells(PMSCs)were transduced with lentiviral vectors carrying Lmxla/NeuroDI to establish genetically engineered PMSCs(LN-PMSCs)and induce their diferentiation into dopaminergic neurons.The LN-PMSCs were then transplanted into the right medial forebrain bundle region of PD model rats prepared using the 6-Hydroxydopamine(6-OHDA)method.Four weeks post-transplantation,the survival and diferentiation of the cells in the brain and motor function of the PD rats were evaluated.Results:The results showed that after 12 days of induction,the genetically modified LN-PMSCs had differentiated into a large number of dopaminergic neurons.Four weeks post-transplantation,these cells significantly improved motor dysfunction in PD rats and promoted the expression of neuron marker TUI,dopaminergic neuron markers FOXA2 and TH,gamma-aminobutyric acid-ergic(GABAergic)neuron marker GABA,astrocyte marker GFAP,presynaptic marker SYN,and postsynaptic marker PSD95 in the transplantation area.Conclusion:Our findings suggest that the gene-engineered PMSCs cell line overexpressing Lmxla and NeuroDI(LN-PMSCs)transplantation could be a potential therapeutic strategy for treating PD.
基金funded by the National Key Research and Development Program(grant number 2017YFD0601100)。
文摘Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainability and management of teak plantations in hilly areas.
基金supported by Key Research and Development Plan of Shandong Province, China (2017GGX20140)Natural Science Foundation of Shandong Province, China (No. ZR2014JL031)
文摘The fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints was studied by high- frequency fatigue test and finite element （FE） methods. The fatigue test results showed that a better enhancement of fatigue life was achieved for the joints with highlocked bolts by employing the combinations of cold expansion, interference fit, and clamping force. The fractography revealed that fatigue cracks propagated tortuously; more fatigue micro-cliffs, tearing ridges, lamellar structure were observed, and fatigue striation spacing was simultaneously reduced. The evaluation of residual stress conducted by FE methods confirmed the experimental results and locations of fatigue crack initiation. The extension of fatigue lives can be attributed to the evolution of fatigue damage and effect of beneficial compressive residual stresses around the hole, resulting in the delay of crack initiation, crack deflection, and plasticityinduced crack closure.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.
基金supported by Natural Science Foundation of China(Nos.11664008,11464009 and 61761015)Natural Science Foundation of Guangxi(Nos.2017GXNSFDA198027,2017GXNSFFA198011 and 2015GXNSFDA139033)Project of Guangxi Scientific Research and Technical Development(No.1348020-11).
文摘(1-x)LiCuNb_(3)O_(9)-Bi(Mg_(0.5)Zr_(0.5))O_(3) ceramics((1-x)LCN-xBMZ)with 0≤x≤0.08 were synthesized by a solid-state reaction method.The phase structure of(1-x)LCN-xBMZ ceramics was characterized by X ray diffraction(XRD),which revealed that the ceranics were distorted cubic perovskite structures.Apparent giant permitivity of 1.98× 10^(4)-1.05× 10^(5) at 100kHz over the measured temperature range(259℃-250℃)was observed in the sintered(1-x)LCN-xBMZ(0≤x≤0.08)ceramics.Especially for the sample of x=0.04,the temperature stability of permitivity was markedly increased(△ε/ε100℃≤±15%),and high relative permitivity(>8.3 × 10^(4))were obtained over a wide temperature range from 100℃ to 250℃at 100 kHz,which indicates that this ceramic is a promising dielectrice material for elevated temperature dielectrics.The giant dielectric property of(1-x)LCN-xBMZ ceramics are profoundly concerned with the Maxwell-Wagner effect.
