Objective:To explore the relationships among ambient temperature,ischemic stroke severity,and blood pressure.Methods:Meteorological data(2005–2015)were collected from the Guangzhou Meteorological Data Service.Ischemi...Objective:To explore the relationships among ambient temperature,ischemic stroke severity,and blood pressure.Methods:Meteorological data(2005–2015)were collected from the Guangzhou Meteorological Data Service.Ischemic stroke patients from the Department of Neurology of the First Affiliated Hospital,Sun Yat-sen University were retrospectively evaluated,each winter from 2005 to 2015.Patient demographics,baseline measurements,and National Institute of Health Stroke Scale(NIHSS)score were evaluated.Results:Three hundred sixty-two patients were included.The median latency from symptom onset to admission was 2 d(IQR:1–3 d).During recruitment,the highest and lowest temperatures were 39℃and 1.3℃,respectively.Hypertension was the most common comorbidity(75.1%).NIHSS scores at admission and discharge were higher in the cold-exposed group than in the controls regardless of the average temperature at admission.In addition,systolic and diastolic blood pressure values at admission were higher in the cold-exposed group than in the controls.When stratified by hypertensive status,the average and minimum temperatures at admission were negatively associated with systolic and diastolic blood pressure values in hypertensive patients.Reductions in the average and minimum temperatures at symptom onset were associated with more severe stroke.Conclusion:Ischemic stroke patients with symptom onset in winter had higher systolic blood pressure values and more serious neurologic deficits upon admission.展开更多
A novel‐structured Mo‐Cu‐Fe‐O composite was successfully prepared by co‐precipitation and impregnation method.The properties of the as‐prepared samples were determined using X‐ray diffraction,temperature‐progr...A novel‐structured Mo‐Cu‐Fe‐O composite was successfully prepared by co‐precipitation and impregnation method.The properties of the as‐prepared samples were determined using X‐ray diffraction,temperature‐programmed reduction by H2,cyclic voltammetry,and temperature‐programmed desorption by O2.The results showed that Mo6+diffused into the Cu‐Fe‐O crystal lattice and then formed a new crystalline phase of CuMoO4.The Mo‐Cu‐Fe‐O catalyst had redox properties,and its surface contained active sites for oxygen adsorption.In addition,the catalytic activity of the Mo‐Cu‐Fe‐O composite was evaluated by the degradation of Cationic Red GTL,Crystal Violet,and Acid Red in catalytic wet air oxidation(CWAO)at ambient temperature and pressure.The Mo‐Cu‐Fe‐O catalyst showed excellent activity at basic conditions for the degradation of Cationic Red GTL.High removal efficiencies of91.5%and92.8%were achieved for Cationic Red GTL and Crystal Violet,respectively,in wastewater,and the efficiency remained high after seven cycles.However,almost no degradation of Acid Red occurred in the CWAO process.Furthermore,hydroxyl radicals were formed in the CWAO process,which induced the decomposition of the two cationic dyes in wastewater,and the toxicity of their effluents was decreased after degradation.The results indicate that the Mo‐Cu‐Fe‐O composite shows excellent catalytic activity for the treatment of wastewater contaminated with cationic dyes.展开更多
Introduction With the development of scientific technology, people continuously search for new methods which can accelerate reactions. Nowadays as a new technology, microwave irradiation has gained much practical impo...Introduction With the development of scientific technology, people continuously search for new methods which can accelerate reactions. Nowadays as a new technology, microwave irradiation has gained much practical importance in chemical reactions. Microwave irradiation has been applied successfully to the areas, such as inorganic synthesis, the prepara-展开更多
A chemical reaction for the preparation of B-C-N compounds by using carbon tetrachloride （CC14）, boron tribromide （BBr3）, lithium nitride （Li3N） and sodium as reactants has been carried out at the temperature of...A chemical reaction for the preparation of B-C-N compounds by using carbon tetrachloride （CC14）, boron tribromide （BBr3）, lithium nitride （Li3N） and sodium as reactants has been carried out at the temperature of 400℃. Measurements of FTIR, XRD, TEM and EELS show that two kinds of compounds have been formed in the prepared sample. One is hollow sphere-like C-N with an amorphous, structure; the other is piece-like polycrystalline B-C-N with the hexagonal structure. Their determined compositions are close to C3N and BC2N, respectively.展开更多
Samaria-doped ceria Ce0.8Sm0.2O2-δ(SDC) and SmFe0.7Cu0.3-xNixO3 have been synthesized by the sol-gel method and characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM) and scanning electron micr...Samaria-doped ceria Ce0.8Sm0.2O2-δ(SDC) and SmFe0.7Cu0.3-xNixO3 have been synthesized by the sol-gel method and characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM) and scanning electron microscopy(SEM).The electrochemical synthesis of ammonia was investigated at atmospheric pressure and low temperature,using the SFCN materials as the cathode,a Nafion membrane as the electrolyte,nickel-doped SDC(Ni-SDC) as the anode and silver-platinum paste as the current collector.Ammonia was synthesized from 25 to 100℃ when the SFCN materials were used as cathode,with SmFe0.7Cu0.1Ni0.2O3 giving the highest rates of ammonia formation.The maximum rate of evolution of ammonia was 1.13 × 10-8 mol·cm-2·s-1 at 80℃,and the current efficiency reached as high as 90.4%.展开更多
Recent results on conversion from graphite to diamond by aid of non-metallic catalysts are reviewed. The current status of experimental advances is presented and typical examples from relevant literature are provided ...Recent results on conversion from graphite to diamond by aid of non-metallic catalysts are reviewed. The current status of experimental advances is presented and typical examples from relevant literature are provided for understanding the mechanism of the graphite-diamond conversion by aid of these non-metallic catalysts. Furthermore, a tendency of graphite-diamond transformation assisted by carbonates, sulfates or phosphorus under high pressure and high temperature has been investigated by calculating the activation energy and transformation probability of the carbon atoms over a potential barrier. It was found that the activation energy is highly sensitive to the catalyst chosen. The probability sequence of graphite-diamond transformation with these catalysts was put forward.展开更多
A novel scale-up ambient pressure synthetic strategy for the preparation of imine-based covalent organic frameworks（COFs） was proposed through dynamic imine exchange reaction mechanism. The obtained COFs exhibited g...A novel scale-up ambient pressure synthetic strategy for the preparation of imine-based covalent organic frameworks（COFs） was proposed through dynamic imine exchange reaction mechanism. The obtained COFs exhibited good crystallinity and much higher porosity comparable to their solvothermally synthesized counterparts. Moreover, under ambient pressure, the COF nanofibers could readily grow on the surface of polyimide films, and the resulted nanocomposite film showed an interesting colorimetric acid-responsive behavior.展开更多
Based upon the thermodynamic analysis of the nucleation of d iamond crystal, the effects of synthesis temperature and pressure on the nucleat ion of diamond crystal, diamond growth and output of diamond crystal, parti...Based upon the thermodynamic analysis of the nucleation of d iamond crystal, the effects of synthesis temperature and pressure on the nucleat ion of diamond crystal, diamond growth and output of diamond crystal, particle s ize and strength were discussed. The results show that the excess pressure has a n important effect on the critical radius of nucleation and thermodynamic b a rrier in the formation of a critical nucleus. Considering the excess pressure, t he expression of diamond nucleation rate was obtained.展开更多
Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperatur...Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.展开更多
Trees create microclimate under their crowns in comparison to the outside ambient atmosphere, which is a result of physical as well as physiological functions of the tree. The cooling produced by trees varies with spe...Trees create microclimate under their crowns in comparison to the outside ambient atmosphere, which is a result of physical as well as physiological functions of the tree. The cooling produced by trees varies with species due to variation in several anatomical, structural and physiological attributes of the species. Transpiration is one of the most significant physiological functions performed by plants, which affects cooling produced by a tree under its shade. When solar energy impinges on the leaf, water emerges from its surface through transpiration taking the latent heat to convert it into water vapour. This leads to a rise in humidity of the atmosphere and reduction in temperature of the leaf. To remain leaf in equilibrium, it takes heat from the surrounding atmosphere resulting in reduction in temperature of surroundings. Since, transpiration takes place through stomata which are normally located on the ventral side of the leaf, this reduction in temperature is more experienced beneath the crown of the tree. Therefore, the present study was carried out to analyze the role of transpiration in cooling effect of five forestry tree species. The cooling produced by tree species under their shades has been found positively correlated to the transpiration rate whereas the rate of transpiration has responded positively to the ambient temperature and water conductance. However, no definite relationship has been found between frequency of open stomata and the rate of transpiration.展开更多
文摘Objective:To explore the relationships among ambient temperature,ischemic stroke severity,and blood pressure.Methods:Meteorological data(2005–2015)were collected from the Guangzhou Meteorological Data Service.Ischemic stroke patients from the Department of Neurology of the First Affiliated Hospital,Sun Yat-sen University were retrospectively evaluated,each winter from 2005 to 2015.Patient demographics,baseline measurements,and National Institute of Health Stroke Scale(NIHSS)score were evaluated.Results:Three hundred sixty-two patients were included.The median latency from symptom onset to admission was 2 d(IQR:1–3 d).During recruitment,the highest and lowest temperatures were 39℃and 1.3℃,respectively.Hypertension was the most common comorbidity(75.1%).NIHSS scores at admission and discharge were higher in the cold-exposed group than in the controls regardless of the average temperature at admission.In addition,systolic and diastolic blood pressure values at admission were higher in the cold-exposed group than in the controls.When stratified by hypertensive status,the average and minimum temperatures at admission were negatively associated with systolic and diastolic blood pressure values in hypertensive patients.Reductions in the average and minimum temperatures at symptom onset were associated with more severe stroke.Conclusion:Ischemic stroke patients with symptom onset in winter had higher systolic blood pressure values and more serious neurologic deficits upon admission.
基金supported by the National Natural Science Foundation of China(51678511,51308484)the Natural Science Foundation of Hunan Province(13JJ4049)+3 种基金the Education Department Fund of Hunan Province(14C1094)the Open Fund of Key Laboratory of Mineralogy and Metallogeny in Chinese Academy of Sciences(KLMM20150104)the Major Talent Training Program of Xiangtan University(16PYZ09)the Specialized Research Fund for the Doctoral Program of Xiangtan University(12QDZ18)~~
文摘A novel‐structured Mo‐Cu‐Fe‐O composite was successfully prepared by co‐precipitation and impregnation method.The properties of the as‐prepared samples were determined using X‐ray diffraction,temperature‐programmed reduction by H2,cyclic voltammetry,and temperature‐programmed desorption by O2.The results showed that Mo6+diffused into the Cu‐Fe‐O crystal lattice and then formed a new crystalline phase of CuMoO4.The Mo‐Cu‐Fe‐O catalyst had redox properties,and its surface contained active sites for oxygen adsorption.In addition,the catalytic activity of the Mo‐Cu‐Fe‐O composite was evaluated by the degradation of Cationic Red GTL,Crystal Violet,and Acid Red in catalytic wet air oxidation(CWAO)at ambient temperature and pressure.The Mo‐Cu‐Fe‐O catalyst showed excellent activity at basic conditions for the degradation of Cationic Red GTL.High removal efficiencies of91.5%and92.8%were achieved for Cationic Red GTL and Crystal Violet,respectively,in wastewater,and the efficiency remained high after seven cycles.However,almost no degradation of Acid Red occurred in the CWAO process.Furthermore,hydroxyl radicals were formed in the CWAO process,which induced the decomposition of the two cationic dyes in wastewater,and the toxicity of their effluents was decreased after degradation.The results indicate that the Mo‐Cu‐Fe‐O composite shows excellent catalytic activity for the treatment of wastewater contaminated with cationic dyes.
文摘Introduction With the development of scientific technology, people continuously search for new methods which can accelerate reactions. Nowadays as a new technology, microwave irradiation has gained much practical importance in chemical reactions. Microwave irradiation has been applied successfully to the areas, such as inorganic synthesis, the prepara-
基金Supported by the National Natural Science Foundation of China under Grant Nos 50225207, 10325417, 50372055, 50472051 and 50532020, and the National Basic Research Programme of China under Grant No 2005CB724400.
文摘A chemical reaction for the preparation of B-C-N compounds by using carbon tetrachloride （CC14）, boron tribromide （BBr3）, lithium nitride （Li3N） and sodium as reactants has been carried out at the temperature of 400℃. Measurements of FTIR, XRD, TEM and EELS show that two kinds of compounds have been formed in the prepared sample. One is hollow sphere-like C-N with an amorphous, structure; the other is piece-like polycrystalline B-C-N with the hexagonal structure. Their determined compositions are close to C3N and BC2N, respectively.
基金Supported by the National Natural Science Foundation of China (Grant No. 20863007)
文摘Samaria-doped ceria Ce0.8Sm0.2O2-δ(SDC) and SmFe0.7Cu0.3-xNixO3 have been synthesized by the sol-gel method and characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM) and scanning electron microscopy(SEM).The electrochemical synthesis of ammonia was investigated at atmospheric pressure and low temperature,using the SFCN materials as the cathode,a Nafion membrane as the electrolyte,nickel-doped SDC(Ni-SDC) as the anode and silver-platinum paste as the current collector.Ammonia was synthesized from 25 to 100℃ when the SFCN materials were used as cathode,with SmFe0.7Cu0.1Ni0.2O3 giving the highest rates of ammonia formation.The maximum rate of evolution of ammonia was 1.13 × 10-8 mol·cm-2·s-1 at 80℃,and the current efficiency reached as high as 90.4%.
基金Project supported by the National Natural Science Foundation of China (Grant No. 19674970).
文摘Recent results on conversion from graphite to diamond by aid of non-metallic catalysts are reviewed. The current status of experimental advances is presented and typical examples from relevant literature are provided for understanding the mechanism of the graphite-diamond conversion by aid of these non-metallic catalysts. Furthermore, a tendency of graphite-diamond transformation assisted by carbonates, sulfates or phosphorus under high pressure and high temperature has been investigated by calculating the activation energy and transformation probability of the carbon atoms over a potential barrier. It was found that the activation energy is highly sensitive to the catalyst chosen. The probability sequence of graphite-diamond transformation with these catalysts was put forward.
基金financially supported by the National Natural Science Foundation of China (Nos. 21174089, 21674068 and 51633004)
文摘A novel scale-up ambient pressure synthetic strategy for the preparation of imine-based covalent organic frameworks（COFs） was proposed through dynamic imine exchange reaction mechanism. The obtained COFs exhibited good crystallinity and much higher porosity comparable to their solvothermally synthesized counterparts. Moreover, under ambient pressure, the COF nanofibers could readily grow on the surface of polyimide films, and the resulted nanocomposite film showed an interesting colorimetric acid-responsive behavior.
文摘Based upon the thermodynamic analysis of the nucleation of d iamond crystal, the effects of synthesis temperature and pressure on the nucleat ion of diamond crystal, diamond growth and output of diamond crystal, particle s ize and strength were discussed. The results show that the excess pressure has a n important effect on the critical radius of nucleation and thermodynamic b a rrier in the formation of a critical nucleus. Considering the excess pressure, t he expression of diamond nucleation rate was obtained.
文摘Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.
文摘Trees create microclimate under their crowns in comparison to the outside ambient atmosphere, which is a result of physical as well as physiological functions of the tree. The cooling produced by trees varies with species due to variation in several anatomical, structural and physiological attributes of the species. Transpiration is one of the most significant physiological functions performed by plants, which affects cooling produced by a tree under its shade. When solar energy impinges on the leaf, water emerges from its surface through transpiration taking the latent heat to convert it into water vapour. This leads to a rise in humidity of the atmosphere and reduction in temperature of the leaf. To remain leaf in equilibrium, it takes heat from the surrounding atmosphere resulting in reduction in temperature of surroundings. Since, transpiration takes place through stomata which are normally located on the ventral side of the leaf, this reduction in temperature is more experienced beneath the crown of the tree. Therefore, the present study was carried out to analyze the role of transpiration in cooling effect of five forestry tree species. The cooling produced by tree species under their shades has been found positively correlated to the transpiration rate whereas the rate of transpiration has responded positively to the ambient temperature and water conductance. However, no definite relationship has been found between frequency of open stomata and the rate of transpiration.
