The objective of this study is the phytochemical analysis and the determination of the antibacterial activity of aqueous and hydro-ethanolic extracts obtained from the leaves and bark of the trunk of Albizia zygia, ag...The objective of this study is the phytochemical analysis and the determination of the antibacterial activity of aqueous and hydro-ethanolic extracts obtained from the leaves and bark of the trunk of Albizia zygia, against Escherichia coli and Salmonella typhi bacteria in aquatic microcosms. Phytochemical screening was performed as described by Pareck. The results obtained show that the hydro-ethanolic and aqueous extracts of Albizia zygia trunk bark recorded higher extraction yields (26.71% and 33.2% respectively) compared to the aqueous and hydro-ethanolic extracts of leaves of the same plant. Secondary metabolites with antibacterial activities such as anthraquinones, anthocyanins, flavonoids, polyphenols, tannins and saponins were found in both types of extracts. Flavonoids and anthocyanins were relatively more abundant than the other chemical constituents. The highest cellular inhibition rate of Escherichia coli was 99.88%, obtained after 9 hours of exposure in the hydro-ethanolic extract solution of trunk bark at the concentration 1.5 g/L. The Salmonella typhi rate was 99.95% after 9 hours of exposure of bacterial cells to the hydro-ethanol extract of the bark of the trunk at the concentration 1.5 g/L. This rate increased proportionally with the bacterial-extract contact time. The temperature of the medium did not significantly influence bacterial inhibition (P > 0.05). The obtained results justify the use of the plant Albizia zygia in the reduction of the flow of bacterio-pollutants contained in water intended for consumption.展开更多
BACKGROUND Chronic gastritis(CG)is a common gastrointestinal disorder characterized by inflammation of the stomach lining.Liver-stomach disharmony(LSD)syndrome is believed to contribute to CG symptoms.AIM To evaluate ...BACKGROUND Chronic gastritis(CG)is a common gastrointestinal disorder characterized by inflammation of the stomach lining.Liver-stomach disharmony(LSD)syndrome is believed to contribute to CG symptoms.AIM To evaluate the efficacy and safety of microcosmic syndrome differentiation and Chinese herbal medicine(CHM)treatment in patients with CG and LSD syndrome.METHODS Sixty-four patients with CG and LSD syndrome were randomly divided into two groups:The treatment group received CHM based on microcosmic syndrome differentiation and the control group received conventional Western medicine.The treatment course lasted 12 wk.The primary outcome was improvement in dyspeptic symptoms,measured using the Nepean Dyspepsia Index.The secondary outcomes included the improvement rate of endoscopic findings,histopathological findings,and microcosmic syndrome scores and the incidence of adverse events.RESULTS After 12 wk of treatment,the treatment group showed significantly greater improvement in dyspeptic symptoms than the control group(93.75%vs 65.63%,P<0.01).The treatment group also showed a significantly higher improvement rate in endoscopic findings than the control group(81.25%vs 53.13%,P<0.05).The improvement rates of histopathological findings and microcosmic syndrome scores were not significantly different between the two groups(P>0.05).No serious adverse events were observed in either group.CONCLUSION Microcosmic syndrome differentiation and CHM treatment can effectively improve dyspeptic symptoms and endoscopic findings in patients with CG and LSD syndrome and have a good safety profile.Further studies with larger sample sizes and longer follow-up periods are required to confirm the long-term efficacy and mechanism of action of this treatment.展开更多
Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining,...Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining, industrial activities, improper usage of fertilizers and pesticides, and indiscriminate open waste disposal bring about an increase in the presence of heavy metals in the environment. In the Keffi Metropolis, different elements lead to land contamination which debilitates soil quality, plant survival, human well-being, and the environment as a result of extensive dispersion or quantity of heavy metals in the soil and water. In recent years, biochar has emerged as a promising soil amendment for mitigating heavy metal pollution due to its unique physicochemical properties. This paper provides the effects of softwood pellet biochar on the retention of heavy metals in contaminated soils. A microcosm experiment was carried out to investigate the effects of biochar on the retention of heavy metals in contaminated soils. This research aimed to give an overview of the effects of softwood biochar at different temperatures (550˚C and 700˚C) on the retention of heavy metals and metalloids released from the soil during water inundation. The results show that the addition of organic matter (grass chippings) minimizes heavy metal mobilization. Also, biochar at high temperatures is more effective than those at low temperatures. The expected outcome of the research analysis includes providing insights into the role of biochar in retaining heavy metal contamination and further understanding the use of biochar as a sorbent for the management of contaminated soil.展开更多
煤体自身力学性质对瓦斯动力灾害的发生具有重要的影响,为进一步研究软煤和硬煤微观差异性,采用原子力显微镜(AFM)内置PF-QNM模式对两种不同硬度煤样表面进行扫描,结果表明:软煤和硬煤微观形貌及力学性质存在较大差异,软煤表面粗糙度明...煤体自身力学性质对瓦斯动力灾害的发生具有重要的影响,为进一步研究软煤和硬煤微观差异性,采用原子力显微镜(AFM)内置PF-QNM模式对两种不同硬度煤样表面进行扫描,结果表明:软煤和硬煤微观形貌及力学性质存在较大差异,软煤表面粗糙度明显大于硬煤,微观表面起伏较小,但波峰数量较多,可为气体吸附提供较多吸附点位。不同煤样扫描区域内表面弹性模量和粘附力均符合正态分布。受构造作用和变质程度的影响,其微观结构排列较为紧密,弹性模量整体表现为大于硬煤。不同煤样微观力学性质均表现出明显的非均质性,煤体表面具有一定的粘附力,具有突出倾向的软煤表面粘附力大多集中在0~100 nN,硬煤表面粘附力大多集中在100~400 n N,软煤的最大引力作用距离d0要明显小于硬煤。在应力扰动或压力梯度作用下,气体容易发生快速解吸,容易导致煤与瓦斯突出事故。展开更多
The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 ...The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice(T1), no-tillage and ridge culture of rice(T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation(T4)) were measured with the closed chamber technique in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH_4 emission from paddy fields under these land management practices. In 1996 and 1998, CH_4 emission was 71 48% and 78 82%(T2), 65 93% and 57 18%(T3), and 61 53% and 34 22%(T4) of that in T1 during the rice growing season. During the non-rice growing season, CH_4 emission from rice fields was 76 23% in T2 and 38 69% in T1 The accumulated annual CH_4 emission in T2, T3 and T4 in 1996 decreased by 33 53%, 63 30% and 65 73%, respectively, as compared with that in T1 In 1998, the accumulated annual CH_4 emission in T1, T2, T3 and T4 was 116 96 g/m^2, 68 44 g/m^2, 19 70 g/m^2 and 11 80 g/m^2, respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH_4 emission observed. The relative contribution of various influencing factors to CH_4 emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH_4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH_4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH_4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global(climatic) change.展开更多
The relationships between mechanical characteristics of rock and microcosmic mechanism at high temperatures were investigated by MTS815, as well as the stress-strain behavior of granite under the action of temperature...The relationships between mechanical characteristics of rock and microcosmic mechanism at high temperatures were investigated by MTS815, as well as the stress-strain behavior of granite under the action of temperatures ranging from room temperature to 1200 ℃. Based on a micropore structure analyzer and SEM, the changes in rock porosity and micro structural morphology of sample fractures and brittle-plastic characteristics under high temperatures were analyzed. The results are as follows： 1） Mechanical characteristics do not show obvious variations before 800 ℃; strength decreases suddenly after 800 ℃ and bearing capacity is almost lost at 1200 ℃. 2） Rock porosity increases with rising temperatures; the threshold temperature is about 800 ℃; at this temperature its effect is basically uniform with strength decreasing rapidly. 3） The failure type of granite is a brittle tensile fracture at temperatures below 800 ℃ which transforms into plasticity at temperatures higher than 800 ℃ and crystal formation takes place at this time. Chemical reactions take place at 1200 ℃. Failure of granite under high temperature is a common result of thermal stress as indicated by an increase in the thermal expansion coefficient, transformation to crystal formation of minerals and structural chemical reactions.展开更多
Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three dif...Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three different treatments including non-organic addition as the control, low-organic enrichment (2 g DW green algae per 150 mL) and high-organic enrichment (10 g DW green algae per 150 mL). After 21 d, the meiofauna richness decreased in both organic enrichment treatments. Among the three treatments, total meiofauna abundance was significantly different, and the control groups had higher abundance than the other two treatment groups. However, the responses of the meiofauna abundance in the two organic enrichment treatments were non-significantly different. The relationship of meiofaunal abundance and nematode/copepod ratios to organic matter and oxygen level in the microcosm experiments were discussed.展开更多
A greenhouse study was conducted on phytoextraction and accumulation of lead (Pb) and cadmium (Cd) from contaminated soil – water microcosms by the narrow-leaved cattail, Typha angustifolia. The plants were grown in ...A greenhouse study was conducted on phytoextraction and accumulation of lead (Pb) and cadmium (Cd) from contaminated soil – water microcosms by the narrow-leaved cattail, Typha angustifolia. The plants were grown in sandy loam soil containing 1,666 and 38.5 mg/L of Pb(NO3)2 and Cd(NO3)2 respectively. The trends of lead and cadmium by T. angustifolia for all soil – water microcosms suggested interaction effects as decreased soil lead concentrations and increased water cadmium concentrations over time. T. angustifolia expressed trends as increased biomass in all contaminated shoots and roots examined. Cadmium uptake in shoot and root biomass slightly decreased when lead was initially added to the soil but cadmium uptake in root biomass increased after 30 days. Data suggested an interaction between lead and cadmium and possible that lead uptake was inhibited when cadmium was present.展开更多
The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decr...The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decrease the service life of a concrete structure if improperly handled. In this paper the microstructure of concrete is observed by using Scanned Electric Microscope (SEM) through contrasting experiments in media of acid, alkali and salt with that of freezing-thawing in the same medium environment. This study is to supply a certain basis for changing traditional thinking of mechanical design and to combine construction reliability design with durability of concrete design.展开更多
文摘The objective of this study is the phytochemical analysis and the determination of the antibacterial activity of aqueous and hydro-ethanolic extracts obtained from the leaves and bark of the trunk of Albizia zygia, against Escherichia coli and Salmonella typhi bacteria in aquatic microcosms. Phytochemical screening was performed as described by Pareck. The results obtained show that the hydro-ethanolic and aqueous extracts of Albizia zygia trunk bark recorded higher extraction yields (26.71% and 33.2% respectively) compared to the aqueous and hydro-ethanolic extracts of leaves of the same plant. Secondary metabolites with antibacterial activities such as anthraquinones, anthocyanins, flavonoids, polyphenols, tannins and saponins were found in both types of extracts. Flavonoids and anthocyanins were relatively more abundant than the other chemical constituents. The highest cellular inhibition rate of Escherichia coli was 99.88%, obtained after 9 hours of exposure in the hydro-ethanolic extract solution of trunk bark at the concentration 1.5 g/L. The Salmonella typhi rate was 99.95% after 9 hours of exposure of bacterial cells to the hydro-ethanol extract of the bark of the trunk at the concentration 1.5 g/L. This rate increased proportionally with the bacterial-extract contact time. The temperature of the medium did not significantly influence bacterial inhibition (P > 0.05). The obtained results justify the use of the plant Albizia zygia in the reduction of the flow of bacterio-pollutants contained in water intended for consumption.
文摘BACKGROUND Chronic gastritis(CG)is a common gastrointestinal disorder characterized by inflammation of the stomach lining.Liver-stomach disharmony(LSD)syndrome is believed to contribute to CG symptoms.AIM To evaluate the efficacy and safety of microcosmic syndrome differentiation and Chinese herbal medicine(CHM)treatment in patients with CG and LSD syndrome.METHODS Sixty-four patients with CG and LSD syndrome were randomly divided into two groups:The treatment group received CHM based on microcosmic syndrome differentiation and the control group received conventional Western medicine.The treatment course lasted 12 wk.The primary outcome was improvement in dyspeptic symptoms,measured using the Nepean Dyspepsia Index.The secondary outcomes included the improvement rate of endoscopic findings,histopathological findings,and microcosmic syndrome scores and the incidence of adverse events.RESULTS After 12 wk of treatment,the treatment group showed significantly greater improvement in dyspeptic symptoms than the control group(93.75%vs 65.63%,P<0.01).The treatment group also showed a significantly higher improvement rate in endoscopic findings than the control group(81.25%vs 53.13%,P<0.05).The improvement rates of histopathological findings and microcosmic syndrome scores were not significantly different between the two groups(P>0.05).No serious adverse events were observed in either group.CONCLUSION Microcosmic syndrome differentiation and CHM treatment can effectively improve dyspeptic symptoms and endoscopic findings in patients with CG and LSD syndrome and have a good safety profile.Further studies with larger sample sizes and longer follow-up periods are required to confirm the long-term efficacy and mechanism of action of this treatment.
文摘Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining, industrial activities, improper usage of fertilizers and pesticides, and indiscriminate open waste disposal bring about an increase in the presence of heavy metals in the environment. In the Keffi Metropolis, different elements lead to land contamination which debilitates soil quality, plant survival, human well-being, and the environment as a result of extensive dispersion or quantity of heavy metals in the soil and water. In recent years, biochar has emerged as a promising soil amendment for mitigating heavy metal pollution due to its unique physicochemical properties. This paper provides the effects of softwood pellet biochar on the retention of heavy metals in contaminated soils. A microcosm experiment was carried out to investigate the effects of biochar on the retention of heavy metals in contaminated soils. This research aimed to give an overview of the effects of softwood biochar at different temperatures (550˚C and 700˚C) on the retention of heavy metals and metalloids released from the soil during water inundation. The results show that the addition of organic matter (grass chippings) minimizes heavy metal mobilization. Also, biochar at high temperatures is more effective than those at low temperatures. The expected outcome of the research analysis includes providing insights into the role of biochar in retaining heavy metal contamination and further understanding the use of biochar as a sorbent for the management of contaminated soil.
文摘煤体自身力学性质对瓦斯动力灾害的发生具有重要的影响,为进一步研究软煤和硬煤微观差异性,采用原子力显微镜(AFM)内置PF-QNM模式对两种不同硬度煤样表面进行扫描,结果表明:软煤和硬煤微观形貌及力学性质存在较大差异,软煤表面粗糙度明显大于硬煤,微观表面起伏较小,但波峰数量较多,可为气体吸附提供较多吸附点位。不同煤样扫描区域内表面弹性模量和粘附力均符合正态分布。受构造作用和变质程度的影响,其微观结构排列较为紧密,弹性模量整体表现为大于硬煤。不同煤样微观力学性质均表现出明显的非均质性,煤体表面具有一定的粘附力,具有突出倾向的软煤表面粘附力大多集中在0~100 nN,硬煤表面粘附力大多集中在100~400 n N,软煤的最大引力作用距离d0要明显小于硬煤。在应力扰动或压力梯度作用下,气体容易发生快速解吸,容易导致煤与瓦斯突出事故。
文摘The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice(T1), no-tillage and ridge culture of rice(T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation(T4)) were measured with the closed chamber technique in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH_4 emission from paddy fields under these land management practices. In 1996 and 1998, CH_4 emission was 71 48% and 78 82%(T2), 65 93% and 57 18%(T3), and 61 53% and 34 22%(T4) of that in T1 during the rice growing season. During the non-rice growing season, CH_4 emission from rice fields was 76 23% in T2 and 38 69% in T1 The accumulated annual CH_4 emission in T2, T3 and T4 in 1996 decreased by 33 53%, 63 30% and 65 73%, respectively, as compared with that in T1 In 1998, the accumulated annual CH_4 emission in T1, T2, T3 and T4 was 116 96 g/m^2, 68 44 g/m^2, 19 70 g/m^2 and 11 80 g/m^2, respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH_4 emission observed. The relative contribution of various influencing factors to CH_4 emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH_4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH_4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH_4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global(climatic) change.
基金Projects 50579042 supported by the National Natural Science Foundation of China2002CB412705 by the National Basic Research and Development(973) Program of Chinaok060122 by the Young Foundation of China University of Mining & Technology
文摘The relationships between mechanical characteristics of rock and microcosmic mechanism at high temperatures were investigated by MTS815, as well as the stress-strain behavior of granite under the action of temperatures ranging from room temperature to 1200 ℃. Based on a micropore structure analyzer and SEM, the changes in rock porosity and micro structural morphology of sample fractures and brittle-plastic characteristics under high temperatures were analyzed. The results are as follows： 1） Mechanical characteristics do not show obvious variations before 800 ℃; strength decreases suddenly after 800 ℃ and bearing capacity is almost lost at 1200 ℃. 2） Rock porosity increases with rising temperatures; the threshold temperature is about 800 ℃; at this temperature its effect is basically uniform with strength decreasing rapidly. 3） The failure type of granite is a brittle tensile fracture at temperatures below 800 ℃ which transforms into plasticity at temperatures higher than 800 ℃ and crystal formation takes place at this time. Chemical reactions take place at 1200 ℃. Failure of granite under high temperature is a common result of thermal stress as indicated by an increase in the thermal expansion coefficient, transformation to crystal formation of minerals and structural chemical reactions.
基金funded by the National Natural Science Foundation of China(NOs.40730847,40906063,41076090)
文摘Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three different treatments including non-organic addition as the control, low-organic enrichment (2 g DW green algae per 150 mL) and high-organic enrichment (10 g DW green algae per 150 mL). After 21 d, the meiofauna richness decreased in both organic enrichment treatments. Among the three treatments, total meiofauna abundance was significantly different, and the control groups had higher abundance than the other two treatment groups. However, the responses of the meiofauna abundance in the two organic enrichment treatments were non-significantly different. The relationship of meiofaunal abundance and nematode/copepod ratios to organic matter and oxygen level in the microcosm experiments were discussed.
文摘A greenhouse study was conducted on phytoextraction and accumulation of lead (Pb) and cadmium (Cd) from contaminated soil – water microcosms by the narrow-leaved cattail, Typha angustifolia. The plants were grown in sandy loam soil containing 1,666 and 38.5 mg/L of Pb(NO3)2 and Cd(NO3)2 respectively. The trends of lead and cadmium by T. angustifolia for all soil – water microcosms suggested interaction effects as decreased soil lead concentrations and increased water cadmium concentrations over time. T. angustifolia expressed trends as increased biomass in all contaminated shoots and roots examined. Cadmium uptake in shoot and root biomass slightly decreased when lead was initially added to the soil but cadmium uptake in root biomass increased after 30 days. Data suggested an interaction between lead and cadmium and possible that lead uptake was inhibited when cadmium was present.
文摘The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decrease the service life of a concrete structure if improperly handled. In this paper the microstructure of concrete is observed by using Scanned Electric Microscope (SEM) through contrasting experiments in media of acid, alkali and salt with that of freezing-thawing in the same medium environment. This study is to supply a certain basis for changing traditional thinking of mechanical design and to combine construction reliability design with durability of concrete design.
