CO2 is not only the most important greenhouse gas but also an important resource of elemental carbon and oxygen.From the perspective of resource and energy strategy,the conversion of CO2 to chemicals driven by renewab...CO2 is not only the most important greenhouse gas but also an important resource of elemental carbon and oxygen.From the perspective of resource and energy strategy,the conversion of CO2 to chemicals driven by renewable energy is of significance,since it can not only reduce carbon emission by the utilization of CO2 as feedstock but also store low-grade renewable energy as high energy density chemical energy.Although studies on photoelectrocatalytic reduction of CO2 using renewable energy are increasing,artificial bioconversion of CO2 as an important novel pathway to synthesize chemicals has attracted more and more attention.By simulating the natural photosynthesis process of plants and microorganisms,the artificial bioconversion of CO2 can efficiently synthesize chemicals via a designed and constructed artificial photosynthesis system.This review focuses on the recent advancements in artificial bioreduction of CO2,including the key techniques,and artificial biosynthesis of compounds with different carbon numbers.On the basis of the aforementioned discussions,we present the prospects for further development of artificial bioconversion of CO2 to chemicals.展开更多
Twenty-four compounds including eight steroids (1-8), nine triterpenoids (9-16, 24), three flavonoids (20-22), and four benzenecarboxylic derivatives (17-19, 23) were isolated and identified from stems and twi...Twenty-four compounds including eight steroids (1-8), nine triterpenoids (9-16, 24), three flavonoids (20-22), and four benzenecarboxylic derivatives (17-19, 23) were isolated and identified from stems and twigs of medicinal mangrove plant Sonneratia caseolaris. The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data. Among these rnetabolites, compounds 1, 4-20 and 22-24 were isolated and identified for the first time from S. caseolaris. In the in vitro cytotoxic assay against SMMC-7721 human hepatoma cells, compound 21 (3',4',5,7-tetrahydroxyflavone) exhibited significant activity with IC50 2.8 μg/mL, while oleanolic acid (14), 3,3'-di-O-methyl ether ellagic acid (18), and 3,3',4-O-tri-O-methyl ether ellagic acid (19) showed weak activity. None of these compounds displayed significant antibacterial activites.展开更多
Presently the gold standard diagnostic technique for rabies is the direct immunofluorescence assay (dFA) which is very expensive and requires a high level of expertise. There is a need for more economical and user f...Presently the gold standard diagnostic technique for rabies is the direct immunofluorescence assay (dFA) which is very expensive and requires a high level of expertise. There is a need for more economical and user friendly tests, particularly for use in developing countries. We have established one such test called the direct rapid immunohistochemical test (dRIT) for diagnosis of rabies using brain tissue. The test is based on capture of rabies nucleoprotein (N) antigen in brain smears using a cocktail of biotinylated monoclonal antibodies specific for the N protein and color development by streptavidin peroxidase-amino ethyl carbazole and counter staining with haematoxollin. The test was done in parallel with standard FAT dFA using 400 brain samples from different animals and humans. The rabies virus N protein appears under fight microscope as reddish brown particles against a light blue background. There was 100 % correlation between the results obtained by the two tests. Also, interpretation of results by dRIT was easier and only required a light microscope. To conclude, this newly developed dRIT technique promises to be a simple, cost effective diagnostic tool for rabies and will have applicability in field conditions prevalent in developing countries.展开更多
The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interracial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The re...The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interracial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The relationship between the ratio of Fe-Al compound at interface and bonding parameters (such as preheat temperature of steel plate, solid fraction of Al-7graphite slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 516 ℃ for preheat temperature of steel plate, 32.5% for solid fraction of Al-7graphite slurry and 12 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained to be 70.1%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interracial embrittlement, namely, when the ratio of Fe-Al compound at interface is larger than 70.1%, interfacial embrittlement will occur.展开更多
Patients older than 65 years are the fastest growing segment of the cancer population. It is estimated that within 20 years over 75% of cases and 85% of deaths from colorectal cancer (CRC) will be in this setting. Con...Patients older than 65 years are the fastest growing segment of the cancer population. It is estimated that within 20 years over 75% of cases and 85% of deaths from colorectal cancer (CRC) will be in this setting. Concerns about cancer treatment in the elderly relate to comorbidities, which increase proportionally with age, physiological changes associated with aging which may influence drug metabolism and toxicity, and diminishing life expectancy, which particularly impacts decisions surrounding the benefits of adjuvant therapies. Over the last 10 years, significant improvements in the treatment of advanced CRC with combination therapy have been made. The randomized trials which have defined these improvements did not exclude elderly patients. However, the median age of patients in these trials has generally been approximately 60 years. Thus, it appears that some degree of selection is involved with younger and presumably fitter patients being the subjects in most of the pivotal trials. The availability of new molecularly targeted agents and newly improved existing agents has expanded the range of treatment options available. This variety gives greater flexibility in dealing with different subsets of patients, such as the elderly. However, some fit elderly patients seem to tolerate combination therapy reasonably well, while studies on unfit elderly subjects are needed.展开更多
Hydrophilic ceramic membranes would be potential candidates for membrane gas absorption if they could be applied to appropriate separation processes.This study highlights a novel concept for the practical implementati...Hydrophilic ceramic membranes would be potential candidates for membrane gas absorption if they could be applied to appropriate separation processes.This study highlights a novel concept for the practical implementation of SO_2 absorption in hydrophilic ceramic membrane that exhibits outstanding thermal and mechanical stabilities.With this aim,we investigated experimentally the performance of SO_2 absorption into aqueous sodium hydroxide (NaOH) solution in a hydrophilic alumina (Al_2O_3) membrane contactor in terms of SO_2 removal efficiency and SO_2 mass transfer flux,and compared the performance with that in a hydrophobic one.A series of experiments were performed at various conditions over a NaOH concentration range of 0–1.0 mol·L^(-1),a liquid flow rate range of 30–180 ml·min^(-1),a gas flow rate range of 120–1000 ml·min^(-1),an inlet SO_2 concentration range of 400–2000μl·L^(-1),and a temperature range of 10–35°C.It was found that the hydrophilic membrane was more competitive when using a NaOH concentration higher than 0.2 mol·L^(-1).Furthermore,it can be inferred that the hydrophilicα-Al_2O_3 membrane exhibited exceptional long-term stability under 480 h continuous operation.展开更多
To investigate the therapeutic effects and mechanisms of garlicin for treatment of unstable angina pectoris (UAP), garlicin injectio was intravenously dripped 60 mg/day in 34 cases for 10 days. Nitroglycerine was used...To investigate the therapeutic effects and mechanisms of garlicin for treatment of unstable angina pectoris (UAP), garlicin injectio was intravenously dripped 60 mg/day in 34 cases for 10 days. Nitroglycerine was used in 21 cases of the control group. The results showed that the total effective rates in improving symptoms and electrocardiogram after garlicin treatment were respectively 82% and 62%, and that the plasma endothelin and blood sugar levels were markedly lowered in cases with hyperglycemia.展开更多
A 21-day laboratory incubation experiment was conducted to investigate the impact of pesticides (insecticide, herbicide, fungicide) on paddy field soil health under controlled moisture (flooded soil) and temperature (...A 21-day laboratory incubation experiment was conducted to investigate the impact of pesticides (insecticide, herbicide, fungicide) on paddy field soil health under controlled moisture (flooded soil) and temperature (25 ℃) environment. The electron transport system (ETS)/Dehydrogenase activity showed negative correlation with pesticides concentrations, decreased with increase of pesticide concentration. The higher doses(5 to 10 times field rates) of pesticides significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect on the control. The toxicity of pesticides in decreasing the ETS activity was in the order: insecticide > fungicide > herbicide, irrespective of their rates of application. The pesticides increased the soil phenol content, which increased with increasing concentration of agrochemicals. The pesticide application did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to that of ETS activity. The phospholipid content decreased with the addition of pesticides in the order insecticide > fungicide > herbicide and the toxicity was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control.展开更多
A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in...A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L"1 were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1. The percentages of ovigerous females were reduced compared with the control (P〈0.01) after 24 days exposure to concentrations higher than 10 ng TBTO L-1. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase (rm), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration (60 ng LI), where all females aborted their egg sacs, 20 ng TBTO L-1 was the only concentration that significantly decreased rm compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.展开更多
Human beings do not live in nature, they live in culture. Contrary to biological evolution, which is based on genetic inheritance, cultural change is transmitted by instruction. Simple beginnings of culture have been ...Human beings do not live in nature, they live in culture. Contrary to biological evolution, which is based on genetic inheritance, cultural change is transmitted by instruction. Simple beginnings of culture have been observed in various animals. However, the much advanced human culture became possible by its transmission by language, and by its being cumulative. The concept of cultural change as a progressive process, popular by 18th and 19th centuries thinkers, is nowadays rejected, and the uniqueness of each culture stressed. Although, there are some similarities between biological evolution and cultural change, important differences between these processes are emphasized. The rapid rate of cultural change (especially its technological aspect), as compared to the rate of biological evolution, is noted. In addition, some cultural changes led to new phenomena, which in a time of crisis can be annulled. The possible consequences of the different rate of these two processes for humans as individuals, and for their societies are discussed.展开更多
Conversion of natural forests into pure plantation forests is a common management practice in subtropical China.To evaluate the effects of forest conversion on soil fertility, microbe numbers and enzyme activities in ...Conversion of natural forests into pure plantation forests is a common management practice in subtropical China.To evaluate the effects of forest conversion on soil fertility, microbe numbers and enzyme activities in topsoils (0-10 cm)were quantified in two 33-year-old monoculture plantations of Castanopsis kawakamii Hayata (CK) and Cunninghamia lanceolata Lamb. (Chinese fir) (CF), and compared to a neighboring relict natural C. kawakamii forest (NF), in Sanming,Fujian. Five soil samples were collected once each in January, April, July, September and November in 2000 in each forest for laboratory analysis. Over the sampling year, there were significant differences for bacteria, fungi and actinomycetes between forests and between seasons (P < 0.05). The largest bacteria and fungi populations were in NF, while CF contained the greatest number of actinomycetes. There were also significant differences (P < 0.05) with microbial respiration for forests and seasons. Additionally, compared with NF, urease and acid phosphatase were significantly lower (P < 0.05)in CK and CF. Also, the correlations of soil hydrolysable N and available P to soil microbial and enzymatic activities were highly significant (P < 0.01). Thus, to alter the traditional Chinese fir monoculture so as to mimic the natural forest conditions, managing mixed stands of Chinese fir and broadleaf trees or conducting crop rotation of conifers and broadleaf trees as well as minimizing forest disturbances like clear-cutting, slash burning and soil preparing, could be utilized.展开更多
By measuring wetland plants chlorophyll content,malondialdehyde(MDA) content and superoxide dismutase(SOD) enzyme activity,the changes of wetland plant physiological characeristics under different power strength were ...By measuring wetland plants chlorophyll content,malondialdehyde(MDA) content and superoxide dismutase(SOD) enzyme activity,the changes of wetland plant physiological characeristics under different power strength were studied,and the mechanism of electric field on plant physiological characteristics was analyzed to provide a theoretical basis for the pollutant removal ability strengthening of artificial wetland under electricfield.The results showed that compared with the control plants,low-intensity-voltage(1 V and 3 V) had no significant effect on the normal physiological and biochemical indexes of the plants,and the growth trend was better than the control group;with the voltage increasing,plant chlorophyll content,MDA content and SOD activity were greatly affected,indicating that plants were under strong oxidative stress,and the growth was damaged.Therefore,a suitable electric field could enhance the sewage treatment effect of constructed wetland.展开更多
1 Why is the demograpy important? In the half century 2000-2050,there will be a virtual tsunami of aging in the United States.The anticipated increase in the population older than age 65 is 140%,and for the population...1 Why is the demograpy important? In the half century 2000-2050,there will be a virtual tsunami of aging in the United States.The anticipated increase in the population older than age 65 is 140%,and for the population older than age 85,389%.More than half of the current U.S.population can anticipate living to age 80,with a contemporary life expectancy at age 75 of 11 years,and at age 85 of 6 years.展开更多
Jack London was one of the outstanding American writers in the late nineteenth and early twentieth century. The Call of the Wild which was based on the Klondike Gold Rush, was the most famous and popular one in China....Jack London was one of the outstanding American writers in the late nineteenth and early twentieth century. The Call of the Wild which was based on the Klondike Gold Rush, was the most famous and popular one in China. These years, lots of scholars have discussed it from various aspects, such as the contents, the themes, the writing styles and its characters. In this short novel, the protagonist Buck is humanized by the author. He is endowed with lots of human qualities, such as loyalty, brave, self-esteem, intelligence and so on. What are the reasons of humanization of the dog protagonist.? Finding out the reasons could help us understand this novel better and it may offer some references for the research on Jack London' s animal novels.展开更多
The catalytic pyrolyses of rayon have been studied respectively by thermo-gravimetric analysis (TGA) when rayon was treated with phosphoric acid (PA), three ammonium phosphate salts and ammonium sulfate (AS). The air ...The catalytic pyrolyses of rayon have been studied respectively by thermo-gravimetric analysis (TGA) when rayon was treated with phosphoric acid (PA), three ammonium phosphate salts and ammonium sulfate (AS). The air is favorable to the catalysis of dibasic ammonium phosphate (DAP), but not to those of ADP, PA, AP, and AS obviously. It is put forward that a peak’s shape character can be described with the ratio of height to half-height-width (H/W /2) of the peak on a differential thermo-gravimetric (DTG) curve. A flat cracking peak, presenting a more moderate dehydration reaction, has a smaller ratio and could lead to higher carbonization and activation yields. The experimental results prove this view. According to expectation, the order of catalysis is: DAP≥ADP>PA> APAS no catalyst.展开更多
The melting points of organic compounds were estimated using a combined method that includes a backpropagation neural network and quantitative structure property relationship (QSPR) parameters in quantum chemistry. ...The melting points of organic compounds were estimated using a combined method that includes a backpropagation neural network and quantitative structure property relationship (QSPR) parameters in quantum chemistry. Eleven descriptors that reflect the intermolecular forces and molecular symmetry were used as input variables. QSPR parameters were calculated using molecular modeling and PM3 semi-empirical molecular orbital theories. A total of 260 compounds were used to train the network, which was developed using MatLab. Then, the melting points of 73 other compounds were predicted and results were compared to experimental data from the literature. The study shows that the chosen artificial neural network and the quantitative structure property relationships method present an excellent alternative for the estimation of the melting point of an organic compound, with average absolute deviation of 5%.展开更多
The reverse transcription quantitative real-time PCR(RT-qPCR) has become one of the most important techniques of studying gene expression. A set of valid reference genes are essential for the accurate normalization of...The reverse transcription quantitative real-time PCR(RT-qPCR) has become one of the most important techniques of studying gene expression. A set of valid reference genes are essential for the accurate normalization of data. In this study, five candidate genes were analyzed with ge Norm, Norm Finder, Best Keeper and ?Ct methods to identify the genes stably expressed in echiuran Urechis unicinctus, an important commercial marine benthic worm, under abiotic(sulfide stress) and normal(adult tissues, embryos and larvae at different development stages) conditions. The comprehensive results indicated that the expression of TBP was the most stable at sulfide stress and in developmental process, while the expression of EF-1-α was the most stable at sulfide stress and in various tissues. TBP and EF-1-α were recommended as a suitable reference gene combination to accurately normalize the expression of target genes at sulfide stress; and EF-1-α, TBP and TUB were considered as a potential reference gene combination for normalizing the expression of target genes in different tissues. No suitable gene combination was obtained among these five candidate genes for normalizing the expression of target genes for developmental process of U. unicinctus. Our results provided a valuable support for quantifying gene expression using RT-qPCR in U. unicinctus.展开更多
The flash points of organic compounds were estimated using a hybrid method that includes a simple group contribution method (GCM) implemented in an artificial neural network (ANN) with particle swarm optimization (PSO...The flash points of organic compounds were estimated using a hybrid method that includes a simple group contribution method (GCM) implemented in an artificial neural network (ANN) with particle swarm optimization (PSO). Different topologies of a multilayer neural network were studied and the optimum architecture was determined. Property data of 350 compounds were used for training the network. To discriminate different substances the molecular structures defined by the concept of the classical group contribution method were given as input variables. The capabilities of the network were tested with 155 substances not considered in the training step. The study shows that the proposed GCM+ANN+PSO method represent an excellent alternative for the estimation of flash points of organic compounds with acceptable accuracy (AARD = 1.8%; AAE = 6.2 K).展开更多
Objective:To study the role of intracellular calcium signal pathway in the down-regulation of aggrecan induced by cyclic tensile strain in the annulus fibrosus cells. Methods:The expression of aggrecan mRNA and core p...Objective:To study the role of intracellular calcium signal pathway in the down-regulation of aggrecan induced by cyclic tensile strain in the annulus fibrosus cells. Methods:The expression of aggrecan mRNA and core protein were respectively detected with RT-PCR and western blot after the channels transmitting calcium ions were blocked with EGTA, gadolinium and verapamil. Results :EGTA. gadolinium and verapamil partially prevented the effects of cyclic tensile strain on the expression of aggrecan in annulus fibrosus cells. Conclusion:The calcium signaling is involved in the down-regulation of proteoglycan resulting from cyclic tensile strain in the annulus fibrosus cells.展开更多
基金supported by the National Natural Science Foundation of China (91745114, 21802160)the National Key R&D Program of China (2016YFA0202800)+2 种基金Shanghai Sailing Program (18YF1425700)Shanghai Advanced Research Institute Innovation Research Program (Y756812ZZ1(172002),Y756803ZZ1(171003))the support from the Hundred Talents Program of the Chinese Academy of Sciences~~
文摘CO2 is not only the most important greenhouse gas but also an important resource of elemental carbon and oxygen.From the perspective of resource and energy strategy,the conversion of CO2 to chemicals driven by renewable energy is of significance,since it can not only reduce carbon emission by the utilization of CO2 as feedstock but also store low-grade renewable energy as high energy density chemical energy.Although studies on photoelectrocatalytic reduction of CO2 using renewable energy are increasing,artificial bioconversion of CO2 as an important novel pathway to synthesize chemicals has attracted more and more attention.By simulating the natural photosynthesis process of plants and microorganisms,the artificial bioconversion of CO2 can efficiently synthesize chemicals via a designed and constructed artificial photosynthesis system.This review focuses on the recent advancements in artificial bioreduction of CO2,including the key techniques,and artificial biosynthesis of compounds with different carbon numbers.On the basis of the aforementioned discussions,we present the prospects for further development of artificial bioconversion of CO2 to chemicals.
基金Supported by the National Natural Science Foundation of China (No. 30770234)Knowledge Innovation Program of Chinese Academy of Sciences (KZCX2-YW-211-04)Department of Science and Technology of Shandong Province (No.2006GG2205023)
文摘Twenty-four compounds including eight steroids (1-8), nine triterpenoids (9-16, 24), three flavonoids (20-22), and four benzenecarboxylic derivatives (17-19, 23) were isolated and identified from stems and twigs of medicinal mangrove plant Sonneratia caseolaris. The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data. Among these rnetabolites, compounds 1, 4-20 and 22-24 were isolated and identified for the first time from S. caseolaris. In the in vitro cytotoxic assay against SMMC-7721 human hepatoma cells, compound 21 (3',4',5,7-tetrahydroxyflavone) exhibited significant activity with IC50 2.8 μg/mL, while oleanolic acid (14), 3,3'-di-O-methyl ether ellagic acid (18), and 3,3',4-O-tri-O-methyl ether ellagic acid (19) showed weak activity. None of these compounds displayed significant antibacterial activites.
文摘Presently the gold standard diagnostic technique for rabies is the direct immunofluorescence assay (dFA) which is very expensive and requires a high level of expertise. There is a need for more economical and user friendly tests, particularly for use in developing countries. We have established one such test called the direct rapid immunohistochemical test (dRIT) for diagnosis of rabies using brain tissue. The test is based on capture of rabies nucleoprotein (N) antigen in brain smears using a cocktail of biotinylated monoclonal antibodies specific for the N protein and color development by streptavidin peroxidase-amino ethyl carbazole and counter staining with haematoxollin. The test was done in parallel with standard FAT dFA using 400 brain samples from different animals and humans. The rabies virus N protein appears under fight microscope as reddish brown particles against a light blue background. There was 100 % correlation between the results obtained by the two tests. Also, interpretation of results by dRIT was easier and only required a light microscope. To conclude, this newly developed dRIT technique promises to be a simple, cost effective diagnostic tool for rabies and will have applicability in field conditions prevalent in developing countries.
基金Project(50054) supported by the Program for New Century Excellent Talents in Universityproject(20060004020) supported by the Research Fund for the Doctoral Program of Higher Education+1 种基金project(3062017) supported by the Natural Science Foundation of Beijing, Chinaproject(2004SZ007) supported by the Foundation of Beijing Jiaotong University
文摘The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interracial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The relationship between the ratio of Fe-Al compound at interface and bonding parameters (such as preheat temperature of steel plate, solid fraction of Al-7graphite slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 516 ℃ for preheat temperature of steel plate, 32.5% for solid fraction of Al-7graphite slurry and 12 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained to be 70.1%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interracial embrittlement, namely, when the ratio of Fe-Al compound at interface is larger than 70.1%, interfacial embrittlement will occur.
文摘Patients older than 65 years are the fastest growing segment of the cancer population. It is estimated that within 20 years over 75% of cases and 85% of deaths from colorectal cancer (CRC) will be in this setting. Concerns about cancer treatment in the elderly relate to comorbidities, which increase proportionally with age, physiological changes associated with aging which may influence drug metabolism and toxicity, and diminishing life expectancy, which particularly impacts decisions surrounding the benefits of adjuvant therapies. Over the last 10 years, significant improvements in the treatment of advanced CRC with combination therapy have been made. The randomized trials which have defined these improvements did not exclude elderly patients. However, the median age of patients in these trials has generally been approximately 60 years. Thus, it appears that some degree of selection is involved with younger and presumably fitter patients being the subjects in most of the pivotal trials. The availability of new molecularly targeted agents and newly improved existing agents has expanded the range of treatment options available. This variety gives greater flexibility in dealing with different subsets of patients, such as the elderly. However, some fit elderly patients seem to tolerate combination therapy reasonably well, while studies on unfit elderly subjects are needed.
基金Supported by the National Key R&D Plan(2016YFC0205700)the National Natural Science Foundation of China(91534108,21506093,21706114)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20150947,BK20160979)the National High Technology Research and Development Program of China(2012AA03A606)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Hydrophilic ceramic membranes would be potential candidates for membrane gas absorption if they could be applied to appropriate separation processes.This study highlights a novel concept for the practical implementation of SO_2 absorption in hydrophilic ceramic membrane that exhibits outstanding thermal and mechanical stabilities.With this aim,we investigated experimentally the performance of SO_2 absorption into aqueous sodium hydroxide (NaOH) solution in a hydrophilic alumina (Al_2O_3) membrane contactor in terms of SO_2 removal efficiency and SO_2 mass transfer flux,and compared the performance with that in a hydrophobic one.A series of experiments were performed at various conditions over a NaOH concentration range of 0–1.0 mol·L^(-1),a liquid flow rate range of 30–180 ml·min^(-1),a gas flow rate range of 120–1000 ml·min^(-1),an inlet SO_2 concentration range of 400–2000μl·L^(-1),and a temperature range of 10–35°C.It was found that the hydrophilic membrane was more competitive when using a NaOH concentration higher than 0.2 mol·L^(-1).Furthermore,it can be inferred that the hydrophilicα-Al_2O_3 membrane exhibited exceptional long-term stability under 480 h continuous operation.
文摘To investigate the therapeutic effects and mechanisms of garlicin for treatment of unstable angina pectoris (UAP), garlicin injectio was intravenously dripped 60 mg/day in 34 cases for 10 days. Nitroglycerine was used in 21 cases of the control group. The results showed that the total effective rates in improving symptoms and electrocardiogram after garlicin treatment were respectively 82% and 62%, and that the plasma endothelin and blood sugar levels were markedly lowered in cases with hyperglycemia.
文摘A 21-day laboratory incubation experiment was conducted to investigate the impact of pesticides (insecticide, herbicide, fungicide) on paddy field soil health under controlled moisture (flooded soil) and temperature (25 ℃) environment. The electron transport system (ETS)/Dehydrogenase activity showed negative correlation with pesticides concentrations, decreased with increase of pesticide concentration. The higher doses(5 to 10 times field rates) of pesticides significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect on the control. The toxicity of pesticides in decreasing the ETS activity was in the order: insecticide > fungicide > herbicide, irrespective of their rates of application. The pesticides increased the soil phenol content, which increased with increasing concentration of agrochemicals. The pesticide application did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to that of ETS activity. The phospholipid content decreased with the addition of pesticides in the order insecticide > fungicide > herbicide and the toxicity was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control.
基金Supported by the National Basic Research Program of China(973 Program)(No.2005CB422300)
文摘A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L"1 were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1. The percentages of ovigerous females were reduced compared with the control (P〈0.01) after 24 days exposure to concentrations higher than 10 ng TBTO L-1. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase (rm), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration (60 ng LI), where all females aborted their egg sacs, 20 ng TBTO L-1 was the only concentration that significantly decreased rm compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.
文摘Human beings do not live in nature, they live in culture. Contrary to biological evolution, which is based on genetic inheritance, cultural change is transmitted by instruction. Simple beginnings of culture have been observed in various animals. However, the much advanced human culture became possible by its transmission by language, and by its being cumulative. The concept of cultural change as a progressive process, popular by 18th and 19th centuries thinkers, is nowadays rejected, and the uniqueness of each culture stressed. Although, there are some similarities between biological evolution and cultural change, important differences between these processes are emphasized. The rapid rate of cultural change (especially its technological aspect), as compared to the rate of biological evolution, is noted. In addition, some cultural changes led to new phenomena, which in a time of crisis can be annulled. The possible consequences of the different rate of these two processes for humans as individuals, and for their societies are discussed.
基金the Basic Research Program of Fujian Province (No. 2000-F-004).
文摘Conversion of natural forests into pure plantation forests is a common management practice in subtropical China.To evaluate the effects of forest conversion on soil fertility, microbe numbers and enzyme activities in topsoils (0-10 cm)were quantified in two 33-year-old monoculture plantations of Castanopsis kawakamii Hayata (CK) and Cunninghamia lanceolata Lamb. (Chinese fir) (CF), and compared to a neighboring relict natural C. kawakamii forest (NF), in Sanming,Fujian. Five soil samples were collected once each in January, April, July, September and November in 2000 in each forest for laboratory analysis. Over the sampling year, there were significant differences for bacteria, fungi and actinomycetes between forests and between seasons (P < 0.05). The largest bacteria and fungi populations were in NF, while CF contained the greatest number of actinomycetes. There were also significant differences (P < 0.05) with microbial respiration for forests and seasons. Additionally, compared with NF, urease and acid phosphatase were significantly lower (P < 0.05)in CK and CF. Also, the correlations of soil hydrolysable N and available P to soil microbial and enzymatic activities were highly significant (P < 0.01). Thus, to alter the traditional Chinese fir monoculture so as to mimic the natural forest conditions, managing mixed stands of Chinese fir and broadleaf trees or conducting crop rotation of conifers and broadleaf trees as well as minimizing forest disturbances like clear-cutting, slash burning and soil preparing, could be utilized.
基金Supported by Natural Science Foundation of Shanghai(10ZR1400300 )Central University Special Foundation of Basic Research and Operating expenses+1 种基金Creative Group Foundation of the National Natural Science Foundation of China (50721006)Key Discipline construction Project of Shanghai (B604)~~
文摘By measuring wetland plants chlorophyll content,malondialdehyde(MDA) content and superoxide dismutase(SOD) enzyme activity,the changes of wetland plant physiological characeristics under different power strength were studied,and the mechanism of electric field on plant physiological characteristics was analyzed to provide a theoretical basis for the pollutant removal ability strengthening of artificial wetland under electricfield.The results showed that compared with the control plants,low-intensity-voltage(1 V and 3 V) had no significant effect on the normal physiological and biochemical indexes of the plants,and the growth trend was better than the control group;with the voltage increasing,plant chlorophyll content,MDA content and SOD activity were greatly affected,indicating that plants were under strong oxidative stress,and the growth was damaged.Therefore,a suitable electric field could enhance the sewage treatment effect of constructed wetland.
文摘1 Why is the demograpy important? In the half century 2000-2050,there will be a virtual tsunami of aging in the United States.The anticipated increase in the population older than age 65 is 140%,and for the population older than age 85,389%.More than half of the current U.S.population can anticipate living to age 80,with a contemporary life expectancy at age 75 of 11 years,and at age 85 of 6 years.
文摘Jack London was one of the outstanding American writers in the late nineteenth and early twentieth century. The Call of the Wild which was based on the Klondike Gold Rush, was the most famous and popular one in China. These years, lots of scholars have discussed it from various aspects, such as the contents, the themes, the writing styles and its characters. In this short novel, the protagonist Buck is humanized by the author. He is endowed with lots of human qualities, such as loyalty, brave, self-esteem, intelligence and so on. What are the reasons of humanization of the dog protagonist.? Finding out the reasons could help us understand this novel better and it may offer some references for the research on Jack London' s animal novels.
文摘The catalytic pyrolyses of rayon have been studied respectively by thermo-gravimetric analysis (TGA) when rayon was treated with phosphoric acid (PA), three ammonium phosphate salts and ammonium sulfate (AS). The air is favorable to the catalysis of dibasic ammonium phosphate (DAP), but not to those of ADP, PA, AP, and AS obviously. It is put forward that a peak’s shape character can be described with the ratio of height to half-height-width (H/W /2) of the peak on a differential thermo-gravimetric (DTG) curve. A flat cracking peak, presenting a more moderate dehydration reaction, has a smaller ratio and could lead to higher carbonization and activation yields. The experimental results prove this view. According to expectation, the order of catalysis is: DAP≥ADP>PA> APAS no catalyst.
文摘The melting points of organic compounds were estimated using a combined method that includes a backpropagation neural network and quantitative structure property relationship (QSPR) parameters in quantum chemistry. Eleven descriptors that reflect the intermolecular forces and molecular symmetry were used as input variables. QSPR parameters were calculated using molecular modeling and PM3 semi-empirical molecular orbital theories. A total of 260 compounds were used to train the network, which was developed using MatLab. Then, the melting points of 73 other compounds were predicted and results were compared to experimental data from the literature. The study shows that the chosen artificial neural network and the quantitative structure property relationships method present an excellent alternative for the estimation of the melting point of an organic compound, with average absolute deviation of 5%.
基金supported by the National Natural Science Foundation of China (Nos. 31372506 and 31572601)
文摘The reverse transcription quantitative real-time PCR(RT-qPCR) has become one of the most important techniques of studying gene expression. A set of valid reference genes are essential for the accurate normalization of data. In this study, five candidate genes were analyzed with ge Norm, Norm Finder, Best Keeper and ?Ct methods to identify the genes stably expressed in echiuran Urechis unicinctus, an important commercial marine benthic worm, under abiotic(sulfide stress) and normal(adult tissues, embryos and larvae at different development stages) conditions. The comprehensive results indicated that the expression of TBP was the most stable at sulfide stress and in developmental process, while the expression of EF-1-α was the most stable at sulfide stress and in various tissues. TBP and EF-1-α were recommended as a suitable reference gene combination to accurately normalize the expression of target genes at sulfide stress; and EF-1-α, TBP and TUB were considered as a potential reference gene combination for normalizing the expression of target genes in different tissues. No suitable gene combination was obtained among these five candidate genes for normalizing the expression of target genes for developmental process of U. unicinctus. Our results provided a valuable support for quantifying gene expression using RT-qPCR in U. unicinctus.
文摘The flash points of organic compounds were estimated using a hybrid method that includes a simple group contribution method (GCM) implemented in an artificial neural network (ANN) with particle swarm optimization (PSO). Different topologies of a multilayer neural network were studied and the optimum architecture was determined. Property data of 350 compounds were used for training the network. To discriminate different substances the molecular structures defined by the concept of the classical group contribution method were given as input variables. The capabilities of the network were tested with 155 substances not considered in the training step. The study shows that the proposed GCM+ANN+PSO method represent an excellent alternative for the estimation of flash points of organic compounds with acceptable accuracy (AARD = 1.8%; AAE = 6.2 K).
文摘Objective:To study the role of intracellular calcium signal pathway in the down-regulation of aggrecan induced by cyclic tensile strain in the annulus fibrosus cells. Methods:The expression of aggrecan mRNA and core protein were respectively detected with RT-PCR and western blot after the channels transmitting calcium ions were blocked with EGTA, gadolinium and verapamil. Results :EGTA. gadolinium and verapamil partially prevented the effects of cyclic tensile strain on the expression of aggrecan in annulus fibrosus cells. Conclusion:The calcium signaling is involved in the down-regulation of proteoglycan resulting from cyclic tensile strain in the annulus fibrosus cells.