南方灵芝子实体的化学成分

南方灵芝[Ganoderma australe(Fr.)Pat.,Bull.]为一种常见的生长在阔叶树枯立木、倒木和伐桩上的灵芝属真菌,具有很好的药用和保健价值.采用硅胶、凝胶柱色谱、反相ODS柱和高效液相色谱等方法从野生南方灵芝子实体的乙醇提取物中分离到14个化合物,结合核磁共振(1H-NMR,13C-NMR)、质谱(MS)、红外(IR)、紫外(UV)等波谱技术将其分别鉴定为灵芝烯酸G甲酯(Methyl ganoderenate G,1)、灵芝烯酸G(Ganoderenic acid G,2)、灵芝烯酸A(Ganoderenic acid A,3)、灵芝烯酸A甲酯(Methyl ganoderenate A,4)、灵芝烯酸D(Ganoderenic acid D,5)、灵芝烯酸F(Ganoderenic acid F,6)、灵芝酸AP(Ganoderic acid AP,7)、7β,23α-dihydroxy-3,11,15-trioxolanosta-8,20E(22)-dien-26-oic acid(8)、Elfvingic acid A(9)、3β,5α-dihydroxy-(22E,24R)-ergosta-7,22-dien-6-one(10)、对羟基苯甲酸(p-hydroxybenzoic acid,11)、3-羟基-4-甲氧基苯甲酸(3-hydroxy-4-methoxybenzoic acid,12)、油酸-α-单甘油酯(9-octadecenoic acid-2,3-dihydroxypropyl ester,13)及谷甾醇(β-sitosterol,14).其中,化合物1为新化合物,化合物1-9为从南方灵芝中首次分离得到的羊毛甾烷型三萜化合物.     

Research on transesterification parameters for producing plant sterols with supercritical methanol

The supercritical fluid method, regarded as a type of individual production process in the course of preparing plant sterols, has become a promising technology, which possesses advantages of high conversion rate without any pretreatment and need of a catalyst. This study examined the reaction process of the deodorizer distillate (DOD), which mainly included the direct transesterification of DOD to convert into free sterols. The effects of the ratio of methanol to DOD, reaction temperature and time on transesterification were studied. Furthermore, the interactions between different factors were also assessed using the response surface methodology. The optimal conditions obtained were as follows: reaction temperature 553 K, reaction time 80 min, and CH₃OH: DOD = 25:1 (mass ratio). Under these conditions, 36.42% sterol concentration was obtained, which is significantly higher in comparison with the initial sterols’ concentration in raw material (22.45%).     

太湖西部河湖氮污染物来源及转化途径分析

通过2014年枯水、丰水两期监测,综合分析了太湖西部入湖河流与湖区水体及其沉积物的无机氮形态与同位素特征,并利用δ~(15)N识别了太湖西部上游区氮污染来源及转化途径的生物化学作用机制.结果表明:NO_3~--N与NH_4~+-N为研究区域入湖河流无机氮的主要形态,而NO_3~--N为西部湖区水体无机氮的主要形态;δ~(15)N-NO_3~-的数值范围揭示了西部入湖河流在枯水季NO_3~--N主要来源于农用化肥,有少量矿化土壤有机氮,而丰水季则以生活污水为主,有少量矿化土壤有机氮及农用化肥;δ~(15)N-NH_4~+的数值范围说明了生活污水是河流水体NH_4~+-N的主要来源;通过水体及沉积物样品NO_3~--N、NH_4~+-N、δ~(15)N-NO_3~-、δ~(15)N-NH_4~+的协同分析可知,湖区氮的赋存形态主要受湖区水体硝化作用及沉积物内反硝化作用的影响.     

基于Matlab分析的台阶式场地平整方案优化设计

在某市餐厨垃圾处理厂场地平整设计中,利用Matlab软件对台阶式场地平整方案进行优化设计,即在Auto CAD环境下用等高线法计算各级台阶的土方量,用Matlab软件拟合出台阶设计高程和土方量的函数关系式,在约束条件下求解,得到了最优设计高程和基于土方挖填平衡条件下场地平整的最小土方工程量,为工程总平面布置提供优化方案。其分析设计方法可为工业企业台阶式场地的总平面布置设计提供借鉴。     

Investigation of carbonyl compound sources at a rural site in the Yangtze River Delta region of China

Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons, and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25th to 27th November, 2011 was 91.6 ppb, about 7 times the value for the clean period of 7th-8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene (T/B) during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was 5.8 ppb/ppb, significantly higher than the values of 0.2-1.7 ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and 0.40 ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better.     

Molecular diversity of arbuscular mycorrhizal fungi at a large-scale antimony mining area in southern China

Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony (Sb). The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis (PCA) indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis (RDA) showed that Sb contaminationwas the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.     

Adsorption and biodegradation of three selected endocrine disrupting chemicals in river-based artificial groundwater recharge with reclaimed municipal wastewater

Endocrine disrupting chemical(EDC) pollution in river-based artificial groundwater recharge using reclaimed municipal wastewater poses a potential threat to groundwater-based drinking water supplies in Beijing, China. Lab-scale leaching column experiments simulating recharge were conducted to study the adsorption, biodegradation, and transport characteristics of three selected EDCs: 17β-estradiol(E2), 17α-ethinylestradiol(EE2) and bisphenol A(BPA). The three recharge columns were operated under the conditions of continual sterilization recharge(CSR), continual recharge(CR), and wetting and drying alternative recharge(WDAR). The results showed that the attenuation effect of the EDCs was in the order of WDAR CR CSR system and E2 EE2 BPA, which followed first-order kinetics. The EDC attenuation rate constants were 0.0783, 0.0505, and 0.0479 m-1 for E2, EE2 and BPA in the CR system, respectively. The removal rates of E2, EE2, and BPA in the CR system were 98%, 96% and 92%, which mainly depended on biodegradation and were affected by water temperature.In the CR system, the concentrations of BPA, EE2, and E2 in soil were 4, 6 and 10 times higher than in the WDAR system, respectively. According to the DGGE fingerprints, the bacterial community in the bottom layer was more diverse than in the upper layer, which was related to the EDC concentrations in the water-soil system. The dominant group was found to be proteobacteria, including Betaproteobacteria and Alphaproteobacteria, suggesting that these microbes might play an important role in EDC degradation.     

Predicting heavy metals’ adsorption edges and adsorption isotherms on MnO2 with the parameters determined from Langmuir kinetics

Although surface complexation models have been widely used to describe the adsorption of heavy metals, few studies have verified the feasibility of modeling the adsorption kinetics,edge, and isotherm data with one p H-independent parameter. A close inspection of the derivation process of Langmuir isotherm revealed that the equilibrium constant derived from the Langmuir kinetic model, K S-kinetic, is theoretically equivalent to the adsorption constant in Langmuir isotherm, K S-Langmuir. The modified Langmuir kinetic model(MLK model) and modified Langmuir isotherm model(MLI model) incorporating p H factor were developed. The MLK model was employed to simulate the adsorption kinetics of Cu(II), Co(II), Cd(II), Zn(II) and Ni(II) on Mn O2 at p H 3.2 or 3.3 to get the values of K S-kinetic. The adsorption edges of heavy metals could be modeled with the modified metal partitioning model(MMP model), and the values of K S-Langmuir were obtained. The values of K S-kinetic and K S-Langmuir are very close to each other, validating that the constants obtained by these two methods are basically the same. The MMP model with K S-kinetic constants could predict the adsorption edges of heavy metals on Mn O2 very well at different adsorbent/adsorbate concentrations. Moreover, the adsorption isotherms of heavy metals on Mn O2 at various p H levels could be predicted reasonably well by the MLI model with the K S-kinetic constants.     

Sulfide elimination by intermittent nitrate dosing in sewer sediments

The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards, and requires expensive programs for its prevention. The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments. The study was carried out based on lab-scale experiments and batch tests using real sewer sediments. The intermittent nitrate dosing mode and the optimal control condition were investigated. The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment. The oxidation–reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S(nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions of efficient sulfide control with lower carbon source loss. The optimal control condition is feasible for the sulfide elimination in sewer systems.     

植物活性物质对PM_(2.5)致细胞损伤的抗性作用

为研究植物活性物质对PM2.5致细胞损伤的抗性作用,研究了北京城区PM2.5对CHO(Chinese hamster ovary,中国仓鼠卵巢)细胞的损伤作用,并选择植物活性物质绿原酸、阿魏酸和荭草素探讨其对CHO细胞的保护作用.以CCK-8法确定PM2.5的试验剂量和3种活性物质的最佳保护剂量,然后通过彗星试验、微核试验、流式细胞术及Western Blotting分别检测PM2.5的损伤作用及植物活性物质的保护作用.结果表明:1由CHO细胞存活率可知,PM2.5的有效试验剂量为15μg/m L,绿原酸、阿魏酸和荭草素的最佳保护剂量分别为50、20、10μmol/L.2PM2.5可引起CHO细胞明显的DNA损伤、微核形成增加、细胞周期阻滞所致的细胞增殖指数降低,而经阿魏酸、绿原酸和荭草素预处理后,均可减轻PM2.5对细胞的损伤作用,起到了一定的保护作用.3PM2.5能引起CHO细胞中p53和caspase-3蛋白的表达增加,而阿魏酸、绿原酸和荭草素均可使其表达量有所降低.由PM2.5引起的细胞损伤经绿原酸、阿魏酸、荭草素作用后表达量降低.在3种植物活性物质中,以阿魏酸拮抗PM2.5损伤的效果最佳,绿原酸次之,荭草素相对较差.