The extended optima straints of miss distance and Schwartz inequality. To reduce guidance law with terminal conmpact angle is derived by the terminal acceleration and eliminate gravity disturbance absolutely, the obje...The extended optima straints of miss distance and Schwartz inequality. To reduce guidance law with terminal conmpact angle is derived by the terminal acceleration and eliminate gravity disturbance absolutely, the object function, which designs the weight of control command to be the power function of time-to-go＇s reciprocal, is given. And the gravity is considered when building the state equation. Based on the parsing express of the guidance command change with varying time and adjoint system analysis method, the command characteristics and the non-dimensional miss distance of the guidance law are analyzed, a design principle of guidance order coefficients is discussed. Finally, based on the requirement of engineering, the method to calculate the guidance condition and maximal required acceleration of the guidance law is given. The simulation demonstrates that not only the guidance law can satisfy the terminal position and impact angle constraints, but also the terminal acceleration can be converged toward zero, which will support a good situation for the terminal angle of attacking control.展开更多
We conducted a study in Komto Forest in East WoUega Zone, Oromia National Regional State, West Ethiopia for determining vegetation structure and regeneration status in this forest. We systematically sampled 53 quadra...We conducted a study in Komto Forest in East WoUega Zone, Oromia National Regional State, West Ethiopia for determining vegetation structure and regeneration status in this forest. We systematically sampled 53 quadrats （20 m ×20 m） along line transects radiating from the peak of Komto Mountain in eight directions. Vegetation parameters such as DBH, height, seedling and sapling density of woody species, and location and altitude of each quadrat were recorded. In total, 103 woody plant species of 87 genera and 45 families were identified. Analysis of selected tree species revealed different population structures. Generally, the forest was dominated by small trees and shrubs characteristic of secondary regeneration. Observations on the regeneration of the forest indicated that there are woody species that require urgent conservation measures. Based on the results of this study, we recommend detailed ecological studies of various environmental factors such as soil type and properties, and ethnobotanical studies to explore indigenous knowledge on uses of plants.展开更多
Summary： Poly （ADP-ribose） polymerase-1 （PARP-1） inhibitors and histone deacetylase （HDAC） in- hibitors have recently emerged as promising anticancer drugs. The aim of this study was to investigate the effect o...Summary： Poly （ADP-ribose） polymerase-1 （PARP-1） inhibitors and histone deacetylase （HDAC） in- hibitors have recently emerged as promising anticancer drugs. The aim of this study was to investigate the effect of combination treatment with the PARP inhibitor P J34 and HDAC inhibitor SAHA on the proliferation of liver cancer cells. Cell proliferation and apoptosis were assessed in three human liver cancer cell lines （HepG2, Hep3B and HCC-LM3） treated with PJ34 （8 μmol/L） and SAHA （1 panol/L）, alone or combined, by Cell Counting Kit-8 assay and flow cytometry, respectively. The nude mice bear- ing subcutaneous HepG2 tumors were administered different groups of drugs （10 mg/kg PJ34, 25 mg/kg SAHA, 10 mg/kg PJ34＋25 mg/kg SAHA）, and the inhibition rates of tumor growth were compared between groups. The results showed that combined use of P J34 and SAHA could synergistically inhibit the proliferation of liver cancer cell lines HepG2, Hep3B and HCC-LM3. The apoptosis rate of HepG2 cells treated with PJ34＋SAHA was significantly higher than that of HepG2 cells treated with PJ34 or SAHA alone （P〈0.05）. In vivo, the tumor inhibition rates were 53.5%, 61.4% and 82.6% in PJ34, SAHA and PJ34＋SAHA groups, respectively. The combined use of PJ34 and SAHA could significantly inhibit the xenograft tumor growth when compared with use of P J34 or SAHA alone （P〈0.05）. It was led to conclude that P J34 and SAHA can synergistically suppress the proliferation of liver cancer cells.展开更多
Summary： Endothelial dysfunction induced by intermittent hypoxia （IH） participates in obstructive sleep apnea syndrome （OSAS）-associated cardiovascular disorders. Myeloid differentiation primary response 88 （My...Summary： Endothelial dysfunction induced by intermittent hypoxia （IH） participates in obstructive sleep apnea syndrome （OSAS）-associated cardiovascular disorders. Myeloid differentiation primary response 88 （MyD88） and tumor necrosis factor receptor-associated factor 6 （TRAF6） regulate nu- merous downstream adaptors like mitogen-activated protein kinases （MAPKs） and the subsequent oxidative stress and inflammatory responses. This study aimed to characterize the role of MyD88/TRAF6 in IH-treated cell function and its associated signaling. Human umbilical vein endo- thelial cells （HUVECs） were randomly exposed to IH or normoxia for 0, 2, 4 and 6 h. Western blot- ting was used to detect the expression pattern of target gene proteins [angiotensin 1 receptor （AT1R）, p-ERK1/2, p-p38MAPK, MyD88 and TRAF6], and the relationships among these target genes down-regulated by the corresponding inhibitors were studied. Finally, the influence of these target genes on proliferation of HUVECs was also assessed by EdU analysis. Protein levels of AT1R, TRAF6 and p-ERK1/2 were increased after IH exposure, with a slight rise in MyD88 and a dynamic change in p-p38MAPK. The down-regulation of TRAF6 by siRNA reduced ERK1/2 phosphorylation during IH without any effects on ATIR. Blockade of AT1R with valsartan decreased TRAF6 and p-ERK1/2 protein expression after IH exposure. ERK1/2 inhibition with PD98059 suppressed only AT1R expression. IH promoted HUVECs proliferation, which was significantly suppressed by the in- hibition of TRAF6, AT1R and ERK1/2. The findings demonstrate that TRAF6 regulates the prolifera- tion of HUVECs exposed to short-term IH by modulating cell signaling involving ERK1/2 down- stream of AT1R. Targeting the AT1R-TRAF6-p-ERK1/2 signaling pathway might be helpful in re- storing endothelial function.展开更多
The development of injectable bone substitutes(IBS)have obtained great importance in the bone re-generation field,as a strategy to reach hardly accessible defects using minimally invasive techniques and able to fit to...The development of injectable bone substitutes(IBS)have obtained great importance in the bone re-generation field,as a strategy to reach hardly accessible defects using minimally invasive techniques and able to fit to irregular topographies.In this scenario,the association of injectable hydrogels and bone graft granules is emerging as a well-established trend.Particularly,in situ forming hydrogels have arisen as a new IBS generation.An in situ forming and injectable dextrin-based hydrogel(HG)was developed,aiming to act as a carrier of granular bone substitutes and bioactive agents.In this work,the HG was associated to a granular bone substitute(Bonelike)and implanted in goat critical-sized calvarial defects(14mm)for 3,6 and 12weeks.The results showed that HG improved the han-dling properties of the Bonelike granules and did not affect its osteoconductive features,neither impairing the bone regener ation process.Human multipotent mesenchymal stromal cells from the umbilical cord,extracellular matrix hydrolysates and the pro-angiogenic peptide LLKKK18 were also combined with the IBS.These bioactive agents did not enhance the new bone formation significantly under the conditions tested,according to micro-computed tomography and histological analysis.展开更多
Levodopa is the gold-standard treatment for Parkinson＇s disease. However, although it alleviates the clinical symptoms, it cannot delay the progressive apoptosis of dopaminergic neurons or prevent motor complications...Levodopa is the gold-standard treatment for Parkinson＇s disease. However, although it alleviates the clinical symptoms, it cannot delay the progressive apoptosis of dopaminergic neurons or prevent motor complications in the long term. In the present study, we investigated the effect of Shudipingchan granule on neuronal apoptosis in a rat model of Parkinson＇s disease, established by injecting 6-hydroxydopamine into the substantia nigra pars compacta and ventral tegmental area. We then administered levodopa （20 mg/kg intraperitoneally, twice daily） with or without Shudipingchan granule （7.5 mL/kg intragastrically, twice daily）, for 4 weeks. The long-term use of levodopa accel- erated apoptosis of nigral cells and worsened behavioral symptoms by activating the extracellular signal-regulated kinase pathway and downstream apoptotic factors. However, administration of Shudipingchan granule with levodopa reduced expression of phosphorylated extracellular signal-regulated kinase 1/2 and Bax, increased tyrosine hydroxylase and Bcl-2, reduced apoptosis in the substantia nigra, and markedly improved dyskinesia. These findings suggest that Shudipingchan granule suppresses neuronal apoptosis by inhibiting the hyper- phosphorylation of extracellular signal-regulated kinase and downregulating expression of anti-apoptotic genes. Shudipingchan granule, used in combination with levodopa, can effectively reduce the symptoms of Parkinson＇s disease.展开更多
The development of electrical engineering and electronic, communications, smart power grid, and ultra-high voltage transmission technologies have driven the energy system revolution to the next generation: the energy ...The development of electrical engineering and electronic, communications, smart power grid, and ultra-high voltage transmission technologies have driven the energy system revolution to the next generation: the energy internet. Progressive penetration of intermittent renewable energy sources into the energy system has led to unprecedented challenges to the currently wide use of coal-fired power generation technologies. Here, the applications and prospects of advanced coal-fired power generation technologies are analyzed. These technologies can be summarized into three categories:(1) large-scale and higher parameters coal-fired power generation technologies, including 620/650/700 oC ultra-supercritical thermal power and double reheat ultra-supercritical coal-fired power generation technologies;(2) system innovation and specific, highefficiency thermal cycles, which consist of renewable energy-aided coal-fired power generation technologies, a supercritical CO_2 Brayton cycle for coal-fired power plants, large-scale air-cooling coal-fired power plant technologies, and innovative layouts for waste heat utilization and enhanced energy cascade utilization;(3) coal-fired power generation combined with poly-generation technologies, which are represented by integrated gasification combined cycle(IGCC) and integrated gasification fuel cell(IGFC) technologies. Concerning the existing coal-fired power units, which are responsible for peak shaving, possible strategies for enhancing flexibility and operational stability are discussed. Furthermore, future trends for coal-fired power plants coupled with cyber-physical system(CPS) technologies are introduced. The development of advanced, coal-fired power generation technologies demonstrates the progress of science and is suitable for the sustainable development of human society.展开更多
A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major fac...A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major factors that can affect low-speed instability.The mathematic model was established to obtain the change rule of speed andinstantaneous acceleration of the hydraulic motor.Then, Matlab was used to simulate theeffect of nonlinear friction force and hydraulic motor parameters such as coefficient of leakand compression ratio, etc., under low speed.Finally, some measures were proposed toimprove the low-speed stability of the hydraulic motor.展开更多
As China vigorously promotes the development of new energy,photovoltaic power curtailment and wind power curtailment have been effectively resolved.At the same time,the yield from new energy power generation is becomi...As China vigorously promotes the development of new energy,photovoltaic power curtailment and wind power curtailment have been effectively resolved.At the same time,the yield from new energy power generation is becoming an important factor that affects the scale of investment in new energy.This paper focuses on the weather risks faced by wind power producers.By studying current research on weather index insurance in China and abroad,the functions and design methods for weather index insurance have been clarified.In addition,the feasibility of wind-power generation index insurance is discussed.The calculation methods for wind power generation index and the weather index insurance pricing methods for wind power enterprises are proposed.A weather index insurance model for wind power generation was established.The rationality and feasibility of the weather index insurance model proposed in this paper were verified using data from an existing power plant.The simulation results show that wind power enterprises can effectively avoid economic losses caused by weather risks through weather index insurance.展开更多
基金supported by the National Natural Science Foundation of China(50875024)
文摘The extended optima straints of miss distance and Schwartz inequality. To reduce guidance law with terminal conmpact angle is derived by the terminal acceleration and eliminate gravity disturbance absolutely, the object function, which designs the weight of control command to be the power function of time-to-go＇s reciprocal, is given. And the gravity is considered when building the state equation. Based on the parsing express of the guidance command change with varying time and adjoint system analysis method, the command characteristics and the non-dimensional miss distance of the guidance law are analyzed, a design principle of guidance order coefficients is discussed. Finally, based on the requirement of engineering, the method to calculate the guidance condition and maximal required acceleration of the guidance law is given. The simulation demonstrates that not only the guidance law can satisfy the terminal position and impact angle constraints, but also the terminal acceleration can be converged toward zero, which will support a good situation for the terminal angle of attacking control.
文摘We conducted a study in Komto Forest in East WoUega Zone, Oromia National Regional State, West Ethiopia for determining vegetation structure and regeneration status in this forest. We systematically sampled 53 quadrats （20 m ×20 m） along line transects radiating from the peak of Komto Mountain in eight directions. Vegetation parameters such as DBH, height, seedling and sapling density of woody species, and location and altitude of each quadrat were recorded. In total, 103 woody plant species of 87 genera and 45 families were identified. Analysis of selected tree species revealed different population structures. Generally, the forest was dominated by small trees and shrubs characteristic of secondary regeneration. Observations on the regeneration of the forest indicated that there are woody species that require urgent conservation measures. Based on the results of this study, we recommend detailed ecological studies of various environmental factors such as soil type and properties, and ethnobotanical studies to explore indigenous knowledge on uses of plants.
基金supported by grants from the National Natural Science Foundation of China(No.81172293)the New Century Excellent Talent Foundation of Ministry of Education of China(No.NCET-04-0701)
文摘Summary： Poly （ADP-ribose） polymerase-1 （PARP-1） inhibitors and histone deacetylase （HDAC） in- hibitors have recently emerged as promising anticancer drugs. The aim of this study was to investigate the effect of combination treatment with the PARP inhibitor P J34 and HDAC inhibitor SAHA on the proliferation of liver cancer cells. Cell proliferation and apoptosis were assessed in three human liver cancer cell lines （HepG2, Hep3B and HCC-LM3） treated with PJ34 （8 μmol/L） and SAHA （1 panol/L）, alone or combined, by Cell Counting Kit-8 assay and flow cytometry, respectively. The nude mice bear- ing subcutaneous HepG2 tumors were administered different groups of drugs （10 mg/kg PJ34, 25 mg/kg SAHA, 10 mg/kg PJ34＋25 mg/kg SAHA）, and the inhibition rates of tumor growth were compared between groups. The results showed that combined use of P J34 and SAHA could synergistically inhibit the proliferation of liver cancer cell lines HepG2, Hep3B and HCC-LM3. The apoptosis rate of HepG2 cells treated with PJ34＋SAHA was significantly higher than that of HepG2 cells treated with PJ34 or SAHA alone （P〈0.05）. In vivo, the tumor inhibition rates were 53.5%, 61.4% and 82.6% in PJ34, SAHA and PJ34＋SAHA groups, respectively. The combined use of PJ34 and SAHA could significantly inhibit the xenograft tumor growth when compared with use of P J34 or SAHA alone （P〈0.05）. It was led to conclude that P J34 and SAHA can synergistically suppress the proliferation of liver cancer cells.
基金supported by grants from the National Natural Science Foundation of China(No.81070067 and No.81370185)
文摘Summary： Endothelial dysfunction induced by intermittent hypoxia （IH） participates in obstructive sleep apnea syndrome （OSAS）-associated cardiovascular disorders. Myeloid differentiation primary response 88 （MyD88） and tumor necrosis factor receptor-associated factor 6 （TRAF6） regulate nu- merous downstream adaptors like mitogen-activated protein kinases （MAPKs） and the subsequent oxidative stress and inflammatory responses. This study aimed to characterize the role of MyD88/TRAF6 in IH-treated cell function and its associated signaling. Human umbilical vein endo- thelial cells （HUVECs） were randomly exposed to IH or normoxia for 0, 2, 4 and 6 h. Western blot- ting was used to detect the expression pattern of target gene proteins [angiotensin 1 receptor （AT1R）, p-ERK1/2, p-p38MAPK, MyD88 and TRAF6], and the relationships among these target genes down-regulated by the corresponding inhibitors were studied. Finally, the influence of these target genes on proliferation of HUVECs was also assessed by EdU analysis. Protein levels of AT1R, TRAF6 and p-ERK1/2 were increased after IH exposure, with a slight rise in MyD88 and a dynamic change in p-p38MAPK. The down-regulation of TRAF6 by siRNA reduced ERK1/2 phosphorylation during IH without any effects on ATIR. Blockade of AT1R with valsartan decreased TRAF6 and p-ERK1/2 protein expression after IH exposure. ERK1/2 inhibition with PD98059 suppressed only AT1R expression. IH promoted HUVECs proliferation, which was significantly suppressed by the in- hibition of TRAF6, AT1R and ERK1/2. The findings demonstrate that TRAF6 regulates the prolifera- tion of HUVECs exposed to short-term IH by modulating cell signaling involving ERK1/2 down- stream of AT1R. Targeting the AT1R-TRAF6-p-ERK1/2 signaling pathway might be helpful in re- storing endothelial function.
基金This work was funded by the project‘DEXGELERATION-Advanced solu-tions for bone regeneration based on dextrin hydrogels’(Norte-07-0202-FEDER-038853).It was also funded by FCT under the scope of the strategic funding of UID/BIO/04469/2013 and UID/BIM/04293/2013 units and COMPETE 2020(POCI-01-0145-FEDER-006684),BioTecNorte operation(NORTE-01-0145-FEDER-000004)and NORTE-01-0145-FEDER-000012 funded by FEDER under the scope of Norte2020-Programa Operacional Regional do Norte.Isabel Pereira and Ana Rita Caseiro were supported by the grants SFRH/BD90066/2012 and SFRH/BD/101174/2014,respectively,from FCT,Portugal.
文摘The development of injectable bone substitutes(IBS)have obtained great importance in the bone re-generation field,as a strategy to reach hardly accessible defects using minimally invasive techniques and able to fit to irregular topographies.In this scenario,the association of injectable hydrogels and bone graft granules is emerging as a well-established trend.Particularly,in situ forming hydrogels have arisen as a new IBS generation.An in situ forming and injectable dextrin-based hydrogel(HG)was developed,aiming to act as a carrier of granular bone substitutes and bioactive agents.In this work,the HG was associated to a granular bone substitute(Bonelike)and implanted in goat critical-sized calvarial defects(14mm)for 3,6 and 12weeks.The results showed that HG improved the han-dling properties of the Bonelike granules and did not affect its osteoconductive features,neither impairing the bone regener ation process.Human multipotent mesenchymal stromal cells from the umbilical cord,extracellular matrix hydrolysates and the pro-angiogenic peptide LLKKK18 were also combined with the IBS.These bioactive agents did not enhance the new bone formation significantly under the conditions tested,according to micro-computed tomography and histological analysis.
基金financially supported by the National Natural Science Foundation of China,No.81302926,30472207the Major Project of Shanghai Science and Technology Commission of China,No.15401970100the Shanghai Municipal Commission of Health and Family Planning of China,No.ZY3-RCPY-2-2005
文摘Levodopa is the gold-standard treatment for Parkinson＇s disease. However, although it alleviates the clinical symptoms, it cannot delay the progressive apoptosis of dopaminergic neurons or prevent motor complications in the long term. In the present study, we investigated the effect of Shudipingchan granule on neuronal apoptosis in a rat model of Parkinson＇s disease, established by injecting 6-hydroxydopamine into the substantia nigra pars compacta and ventral tegmental area. We then administered levodopa （20 mg/kg intraperitoneally, twice daily） with or without Shudipingchan granule （7.5 mL/kg intragastrically, twice daily）, for 4 weeks. The long-term use of levodopa accel- erated apoptosis of nigral cells and worsened behavioral symptoms by activating the extracellular signal-regulated kinase pathway and downstream apoptotic factors. However, administration of Shudipingchan granule with levodopa reduced expression of phosphorylated extracellular signal-regulated kinase 1/2 and Bax, increased tyrosine hydroxylase and Bcl-2, reduced apoptosis in the substantia nigra, and markedly improved dyskinesia. These findings suggest that Shudipingchan granule suppresses neuronal apoptosis by inhibiting the hyper- phosphorylation of extracellular signal-regulated kinase and downregulating expression of anti-apoptotic genes. Shudipingchan granule, used in combination with levodopa, can effectively reduce the symptoms of Parkinson＇s disease.
基金supported by the National Nature Science Foundation of China(Grant No.51821004)supported by National Soft Science Projects:"Frontier tracking research on science and technology in the field of energy" program
文摘The development of electrical engineering and electronic, communications, smart power grid, and ultra-high voltage transmission technologies have driven the energy system revolution to the next generation: the energy internet. Progressive penetration of intermittent renewable energy sources into the energy system has led to unprecedented challenges to the currently wide use of coal-fired power generation technologies. Here, the applications and prospects of advanced coal-fired power generation technologies are analyzed. These technologies can be summarized into three categories:(1) large-scale and higher parameters coal-fired power generation technologies, including 620/650/700 oC ultra-supercritical thermal power and double reheat ultra-supercritical coal-fired power generation technologies;(2) system innovation and specific, highefficiency thermal cycles, which consist of renewable energy-aided coal-fired power generation technologies, a supercritical CO_2 Brayton cycle for coal-fired power plants, large-scale air-cooling coal-fired power plant technologies, and innovative layouts for waste heat utilization and enhanced energy cascade utilization;(3) coal-fired power generation combined with poly-generation technologies, which are represented by integrated gasification combined cycle(IGCC) and integrated gasification fuel cell(IGFC) technologies. Concerning the existing coal-fired power units, which are responsible for peak shaving, possible strategies for enhancing flexibility and operational stability are discussed. Furthermore, future trends for coal-fired power plants coupled with cyber-physical system(CPS) technologies are introduced. The development of advanced, coal-fired power generation technologies demonstrates the progress of science and is suitable for the sustainable development of human society.
基金Supported by the Natural Science Foundation of Fujian Province of China(2009J01259)Scientific Research Foundation of Department of Education(JB08182)
文摘A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major factors that can affect low-speed instability.The mathematic model was established to obtain the change rule of speed andinstantaneous acceleration of the hydraulic motor.Then, Matlab was used to simulate theeffect of nonlinear friction force and hydraulic motor parameters such as coefficient of leakand compression ratio, etc., under low speed.Finally, some measures were proposed toimprove the low-speed stability of the hydraulic motor.
基金supported by the State Grid Science and Technology Project (Research on Transnational Energy Interaction Simulation and Deduction Technologies of Global Energy Interconnection, JS71-17-004)
文摘As China vigorously promotes the development of new energy,photovoltaic power curtailment and wind power curtailment have been effectively resolved.At the same time,the yield from new energy power generation is becoming an important factor that affects the scale of investment in new energy.This paper focuses on the weather risks faced by wind power producers.By studying current research on weather index insurance in China and abroad,the functions and design methods for weather index insurance have been clarified.In addition,the feasibility of wind-power generation index insurance is discussed.The calculation methods for wind power generation index and the weather index insurance pricing methods for wind power enterprises are proposed.A weather index insurance model for wind power generation was established.The rationality and feasibility of the weather index insurance model proposed in this paper were verified using data from an existing power plant.The simulation results show that wind power enterprises can effectively avoid economic losses caused by weather risks through weather index insurance.
