Evaluation of the Efficacy of Albizia zygia Extracts on Bacterial Inhibition in Aquatic Microcosm

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.

Microcosm──开放的超媒体模型

给出了开放超媒体系所应具有的特征，且对开放的超媒体模型Ｍｉｅｒｏｃｏｓｍ系统进行了分析，研究这—模型的优点和缺点．最后还对将来的应用系统所应具有的功能提出了看法。

森林叶凋落物混合分解的研究I.缩微(Microcosm)实验

采用缩微实验法 ,初步系统研究了杉木叶凋落物分别与火力楠、红栲和木荷 3个阔叶树种之一的叶凋落物两两混合分解的动态变化 ,以探明凋落物混合分解过程中可能存在的相互作用 .结果表明 ,杉木叶凋落物与 3种阔叶树种叶凋落物两两混合分解时所表现出不同的相互作用形式 :杉木与木荷表现出抑制作用 ,杉木与红栲或火力楠表现为较弱的促进作用 .

Response of CH_4 emission of paddy fields to land management practices at a microcosmic cultivation scale in China

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.

Mechanical characteristics and microcosmic mechanisms of granite under temperature loads

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.

Effects of Organic Enrichment on Sandy Beach Meiofauna:A Laboratory Microcosm Experiment

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.

Phytoextraction of Metal Contaminants by Typha Angustifolia: Interaction of Lead and Cadmium in Soil-Water Microcosms

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.

Analyses of concrete microcosmic structure in multi-media environment

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.

Distinct dynamic phases observed in bacterial microcosms

Predicting biodiversity and dynamics of complex communities is a fundamental challenge in ecology.Leveraging bacterial microcosms with well-controlled laboratory conditions,Hu et al.recently performed a direct test of theory predicting that two community-level parameters(i.e.,species pool size and inter-species interaction strength)dictate transitions between three dynamical phases:stable full coexistence,stable partial coexistence,and persistent fluctuations.Generally,communities experience species extinctions before they lose stability as either of the two parameters increases.

Clinical study on microscopic syndrome differentiation and traditional Chinese medicine treatment for liver stomach disharmony in chronic gastritis

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.

不同营养水平调水对贡湖湾湖区水质及浮游藻类影响的模拟研究

为探究“引江济太”工程调水给受水湖区水体带来的生态效应,采用水生微宇宙模型进行为期11 d的室内模拟实验,以太湖贡湖湾湖区为受水水体,引入3组设定好的不同营养盐水平(贫营养水平O、中营养水平M、富营养水平E)的望虞河河水,研究在不同营养盐水平调水影响下,受水水体水生态环境的动态响应过程。结果表明:整个实验过程中,中营养和贫营养调水组的水体TN、NO_(3)^(-)-N、NH4_(+)-N、TP、SRP、TOC含量下降明显,富营养调水组影响效果较中营养和贫营养调水组差;调水提高了受水水体生态系统的多样性和均匀度水平,硅藻等非蓝藻细胞密度增加,蓝藻细胞生长受到竞争胁迫,中营养和贫营养调水的影响作用效果好于富营养水平。RDA分析结果表明,受水水体的pH、DO、SiO_(3)^(2-)-Si、TDS、NO_(3)^(-)-N、SRP是本实验水体影响藻类群落结构的主要环境驱动因子。

一件汉代漆器锥画痕迹研究

本文利用超景深显微镜对漆器上的锥画痕迹进行微观观察和分析,直观验证了王世襄先生对明代黄成所著《髹饰录》中对“鎗划”和“嵌色”技艺的解读,并根据微观测量数据推断出了制作锥画工具的尖端形态。

Effects of Using Softwood Pellet Biochar Prepared at Different Temperatures with Grass Chippings on Retention of Heavy Metals in Contaminated Soils

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.

“宏-微-符”三重表征法在中学化学实验教学中的应用--以“Fe^(2+)与Fe^(3+)的检验”为例

以中学化学课堂实验教学“Fe^(2+)与Fe^(3+)的检验”为例,引导学生先从宏观上观察实验现象,再从微观角度解释实验现象,最后从化学特有的语言—书写“离子反应方程式”进行符号表征。这种“宏-微-符”三重表征法有利于学生学习化学知识和构建三者内在的联系,并培养形成学生化学实验探究学习的特定思维模型。

基于“脾虚邪滞”理论探讨胃解痉多肽表达化生中医病机与微观辨证

胃癌前病变(Gastric precancerous lesions,GPL)具有发展为胃癌的风险,而胃解痉多肽表达化生(Spasmolytic polypeptide expressing metaplasia,SPEM)是GPL的初始步骤,具有恶性进展为胃癌前病变的风险。目前关于该化生阶段发病机制的探讨尚不完整,中医药依托扎实的中医理论基础及丰富的中药资源,在防治GPL上具有独特优势。因此,笔者基于“脾虚邪滞”理论,从疾病的病理生理状态、标志物、信号通路三方面进行微观辨证分析,提出以健脾化瘀解毒法为主要疗法,结合文献分析其可行性,以期为SPEM的中医治疗提供新的思路与方法。

A microcosmic discrete occupant evacuation model based on individual characteristics

The research of occupant evacuation in an emergency is of great benefit to building design and evacuation guidance. In this paper a microcosmic discrete evacuation model based on Cellular Automata (CA) is presented, in which the occupants?individual characteristics are considered. Thus, our model has given a description of evacuation route choice with influencing factors, including: individual knowledge of the building, individual realization of the emergency development, and the attractive and repulsive force between occupants. This model differs somewhat from other models in the attention to the associative and separate effect of influencing factors, based on occupants behaviors. In addition, the model could reveal the phenomenon of escape in fire, as those simulations involving a fire condition have shown.

不同硫化体系对硫化天然橡胶改性沥青性能及微观结构的影响

天然橡胶是一种生物质聚合物,作为沥青改性剂在环境可持续性上具有明显优势。然而,其对沥青物理及流变性能的提升不显著。硫化可以改善天然橡胶改性沥青(Natural rubber modified asphalt,NRMA)的性能,但硫化是一个复杂的过程,硫化体系众多,不同硫化体系对硫化天然橡胶改性沥青(Vulcanized natural rubber modified asphalt,VNRMA)的影响尚不明确,这极大地影响了进一步开发高性能VNRMA以获得更广泛的应用。基于此,本研究通过普通硫化体系(Conventional vulcanization,CV)、半有效硫化体系(Semi-efficient vulcanization,SEV)和有效硫化体系(Efficient vulcanization,EV)制备不同的VNRMA,并探究硫化体系对VNRMA性能及微观结构的影响。结果表明:在高温性能和温度敏感性方面,SEV/VNRMA的复数模量、相位角、车辙因子以及温度敏感性系数VTS表现最好;在低温性能方面,三种硫化体系制备的VNRMA均能满足规范要求,但CV/VNRMA低温性能最佳,更适合在低温环境下使用;相容性方面,SEV/VNRMA的Han曲线在低频区斜率值(1.042)最大,相容性最好;施工和易性方面,SEV/VNRMA占据优势,其通过传统等黏度法确定的拌合温度比CV/VNRMA和EV/VNRMA最大分别降低5℃和5℃,压实温度最大分别降低5℃和6℃。通过FM和FTIR对VNRMA的微观结构和化学结构进行分析,结果显示,相比于CV/VNRMA和EV/VNRMA,SEV/VNRMA更加均匀且致密的网状结构是其在相容性和高温性能方面表现优异的主要内在原因。综上,SEV对NRMA的硫化效果最佳,推荐后续研究使用。

Raman spectroscopic characteristics of microcosmic and photosensitive damage on space structure of liposomes sensitized by hypocrellin and its derivatives

Raman spectroscopic characteristics of microcosmic and photosensitive damage on space structure of DPPC liposomes sensitized by hypocrellin and its derivatives are obvious. The trans conformation decreased and the gauche conformation increased. The longitudinal order_parameter in chains and the lateral order_parameter between chains decreased in different degrees. The lateral packing became loose. Photodamage on the liposomes sensitized by 5 Br hypocrellin B was stronger than that by hypocrellins A and B.

基于CT扫描分析的页岩整体及弱面变形特征研究

在页岩气水平井压裂开发过程中,由于页岩弱面剪切活动导致套管变形损坏,严重影响生产的正常进行。分析了川南泸州地区页岩的地质背景,在围压和温度相同的状况下,以不同孔隙介质类型、不同孔隙压力的条件下,利用CT扫描技术探究了页岩三轴滑动摩擦的宏观和微观变形机理,并对此进行实验。研究结果表明:在孔隙压力80~100 MPa,孔隙压力为80 MPa的酸性溶液为介质的页岩样品整体立体分形维数增加的最大,从2.40增加到2.56,孔隙压力为100 MPa的酸性溶液为介质的页岩样品迂曲度上升最高,从1.95上升到3.56,孔隙压力是90 MPa介质为酸性溶液的样品经过实验后,其立体分形维数反而出现了下降,下降了0.011。在滑动摩擦的面上,实验过后,滑动摩擦面分形维数增长最低的是压力80 MPa。介质是酸性溶液,增长了0.02879。滑动摩擦面分形维数增长最高的介质为中性去离子水,孔隙压力是90 MPa的Y12样品,其分形维数增大了0.20575。