富勒烯化学修饰与生物医学应用研究进展(Trends in Studies on Chemical Modification and Biomedical Applications of Fullerenes)

富勒烯以及内嵌金属富勒烯作为一种新型含碳纳米材料,由于其独特的结构和物理化学性质,在生物、医学、超导、光学及催化等多领域有着极为广阔的应用前景.在生物和医学领域,富勒烯及其衍生物具有抗氧化活性和细胞保护作用、抗菌活性、抗病毒作用、载带药物和肿瘤治疗等活性.但是富勒烯本身难以直接溶于生物友好介质中,且制备过程中残存的有机溶剂容易引起生物毒性,富勒烯需要进行合适的化学修饰来进一步改善其生物活性,这些问题已成为其在生物医学领域应用的主要障碍.在总结国内外相关研究基础上,论文重点综述了富勒烯及其衍生物的生物医学应用,同时对其化学修饰与毒性相关性研究进行了阐述.     

A comparative study of metabolic energy expenditure in the limpets Patella cochlear,P. oculus and P. granularis

Oxygen consumption of 3 species of Patella was measured in air and water at various temperatures. Measurements at constant temperature over a full tidal cycle showed no tidal or light-dark rhythms. Measurements under conditions simulating natural tidal, temperature and day-night cycles allowed calculation of daily respiratory energy budgets. P. cochlear occurs low on the shore, but experiences a food shortage due to intense intraspecific competition. Its rate of respiration is moderate, but metabolic expenditure is kept low because exposure to air is brief and body temperatures seldom rise above 23°C. P. cochlear has a respiratory rate-temperature (R-T) curve which peaks at 20°C and forms a plateau between 20° and 32.5°C. The midshore P. oculus has abundant food and adopts an exploitative strategy. Growth rate is very high, and this high turnover of energy is linked with a high metabolic rate, high Q10 (temperature coefficient) values, high body temperatures during the day-time low tide, and a respiratory R-T curve peaking at 32.5°C. Small P. oculus occur mainly in intertidal pools and respire faster in water, while larger individuals occur on bare rocks and respire faster in air over the upper temperature range. In contrast, the upper-shore P. granularis has little food, and conservation of energy is essential, particularly as its growth rate is moderate and its reprocurve output high. Respiratory losses are reduced by suppression of the R-T curve and low Q10 values, resulting in relative independence of temperature. Small P. granularis occur low on the shore and respire slower in water. Larger individuals occur at high levels due to migration, and respire slower in air. This further reduces respiratory energy losses. The patterns of respiration in these 3 species are thus related to food availability, resulting in exploitative or conservationist strategies.     

Oxygen supply in aquatic ectotherms: partial pressure and solubility together explain biodiversity and size patterns

Aquatic ectotherms face the continuous challenge of capturing sufficient oxygen from their environment as the diffusion rate of oxygen in water is 3 x 10(5) times lower than in air. Despite the recognized importance of oxygen in shaping aquatic communities, consensus on what drives environmental oxygen availability is lacking. Physiologists emphasize oxygen partial pressure, while ecologists emphasize oxygen solubility, traditionally expressing oxygen in terms of concentrations. To resolve the question of whether partial pressure or solubility limits oxygen supply in nature, we return to first principles and derive an index of oxygen supply from Fick's classic first law of diffusion. This oxygen supply index (OSI) incorporates both partial pressure and solubility. Our OSI successfully explains published patterns in body size and species across environmental clines linked to differences in oxygen partial pressure (altitude, organic pollution) or oxygen solubility (temperature and salinity). Moreover, the OSI was more accurately and consistently related to these ecological patterns than other measures of oxygen (oxygen saturation, dissolved oxygen concentration, biochemical oxygen demand concentrations) and similarly outperformed temperature and altitude, which covaried with these environmental clines. Intriguingly, by incorporating gas diffusion rates, it becomes clear that actually more oxygen is available to an organism in warmer habitats where lower oxygen concentrations would suggest the reverse. Under our model, the observed reductions in aerobic performance in warmer habitats do not arise from lower oxygen concentrations, but instead through organismal oxygen demand exceeding supply. This reappraisal of how organismal thermal physiology and oxygen demands together shape aerobic performance in aquatic ectotherms and the new insight of how these components change with temperature have broad implications for predicting the responses of aquatic communities to ongoing global climate shifts.     

Movements and depth/temperature distribution of the ectothermic Scombrid, Acanthocybium solandri (wahoo), in the western North Atlantic

Pop-up satellite archival tags were deployed onto four wahoo during 2006 in the western North Atlantic (~26.5°N, 79.3°W), providing movement, depth, and temperature data collected over a total of 198?days. Straight-line distances between tag deployment and pop-off positions ranged from 162.5 to 1,960.0?km. Wahoo spent >90?% of their time in water <200?m, and >90?% of their time in water between 17.5 and 27.5?°C. Three fish made regular trips to depths >200?m. All four fish had significantly different depth distributions between the dark and light periods (Kruskal–Wallace test, p?相似文献   

Temporal variability in trace metal solubility in a paddy soil not reflected in uptake by rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Alternating flooding and drainage conditions have a strong influence on redox chemistry and the solubility of trace metals in paddy soils. However, current knowledge of how the effects of water management on trace metal solubility are linked to trace metal uptake by rice plants over time is still limited. Here, a field-contaminated paddy soil was subjected to two flooding and drainage cycles in a pot experiment with two rice plant cultivars, exhibiting either high or low Cd accumulation characteristics. Flooding led to a strong vertical gradient in the redox potential (Eh). The pH and Mn, Fe, and dissolved organic carbon concentrations increased with decreasing Eh and vice versa. During flooding, trace metal solubility decreased markedly, probably due to sulfide mineral precipitation. Despite its low solubility, the Cd content in rice grains exceeded the food quality standards for both cultivars. Trace metal contents in different rice plant tissues (roots, stem, and leaves) increased at a constant rate during the first flooding and drainage cycle but decreased after reaching a maximum during the second cycle. As such, the high temporal variability in trace metal solubility was not reflected in trace metal uptake by rice plants over time. This might be due to the presence of aerobic conditions and a consequent higher trace metal solubility near the root surface, even during flooding. Trace metal solubility in the rhizosphere should be considered when linking water management to trace metal uptake by rice over time.     

Post-evaluation of a water pollution control plan: methodology and case study

China has developed more than 20 water pollution control plans for river basins (RBWPs) since 1996. However, the implementation has generally lagged. This paper proposes a three-step, post-evaluation methodology to analyze the implementation result of a RBWP and its influential factors. First, a multi-attribute evaluation method based on an index system is established to score the enforcement results of a RBWP. Indicators measure how well a RBWP has achieved its objectives, which include water quality compliance, pollution load control, project construction, financial inputs, and related management requirements. Second, an interpretive structural model is used to detect the significant factors that affect RBWP implementation. This model can effectively analyze the cause-effect chain and hierarchical relationship among variables. Five groups of factors were identified, namely, plan preparation, water resource endowment, policy, institution, and management. Both qualitative and quantitative methods are employed in the third step to evaluate the extent to which these factors have influenced the execution result of a RBWP, including pre-post contrast, scenario analysis, and correlation analysis. This research then post-evaluated the implementation of the Huai River Basin water pollution control plans (H-RBWPs) over a period of 10 years as a case study. Results showed that the implementation of the H-RBWPs was unsatisfactory during 2001–2005, although it improved during 2006–2010. The poor execution of these plans was partially caused by the underestimation of regional economic development in combination with ineffective industrial structure adjustment policies. Therefore, this case study demonstrates the feasibility and flexibility of the proposed post-evaluation methodology.     

Annual production and molecular weight as an influential factor for environmental distribution of chemicals — a case study in Japan

The changes promoted by treatment of a highly polluted soil with sulphuric acid or calcium hydroxide for changing its pH value are studied by controlling physical properties (particle size, TGA and DTA curves), evolution of metal species (exchangeable, as carbonates, related to Fe‐Mn oxides, linked to organic matter and residual) and metal uptake by plant cultures. Metal contents were determined, after wet digestion with HF—HNO₃—HC1O₄ when necessary, by AAS (Ca, Mg, Cu, Pb, Mn, Fe, Zn) or emission (Na, K). The treatment of soil with successive amounts of sulphuric leads to changes in particle size, hydration properties and exothermic peak for organic matter combustion. Very small changes were, however, detected in the alkaline treatment of soil. Soil treatments do not have practical influence on speciation of some metals (Na, K, Mg, Pb, Mn, Fe), but the intensity of the acid treatment leads to both an increase in the Cu extraction and a decrease in the Ca solubilization, probably through gypsum formation. In the case of zinc a maximum solubility in the middle of the range of acid treatment was observed. The comparison among extractants shows solubilities high for two pollutants (Pb, Cu), associated mainly to Fe—Mn oxides and organic matter, and low for two macrocomponents (Fe, K). The rest of metals, basically present in soil as carbonates or oxides, have intermediate extractions. Pot cultures weights depended mainly on both the treatment of soil (poor development in the more acid sample and drainage difficulties in the rest of acid treatments) and the situation (very low weights in laboratory runs as compared with outside), but the irrigation with water or a diluted sulphuric acid solution (at pH = 4.0) did not produce significant weight changes. Tendencies to increase plant pollution were observed for smaller soil pH, acid irrigation and probably for outside cultures, due to uptake by leaves.     

取代芳烃在共溶剂体系中溶解规律的研究

本文利用紫外分光光度法测定了多种取代芳烃在有机溶剂与水组成的共溶剂体系中的溶解度。实验结果表明：溶质溶解度的对数与有机溶剂的体积分数呈良好的线性关系；利用对数线性模型，以及ＵＮＩＦＡＣ基团贡献法对溶质的溶解度进行了估算，发现估算值与测定值吻合得较好。     

不同海拔高寒放牧草甸的生态系统呼吸与环境因子的关系

在全球变化的背景下,为了研究藏北高寒放牧草甸的生态系统呼吸和土壤呼吸特征,沿着3个海拔高度（4 300、4 500和4 700 m）观测了2010年7-9月白天的呼吸通量。同时,观测了同期的土壤温度、土壤水分含量、空气温度和相对湿度,在定性分析土壤水分含量和呼吸通量关系的基础上,将其分成低、中和高3个水平,在此基础上,分析生态系统呼吸、土壤呼吸与土壤温度、土壤水分含量、空气温度以及相对湿度的关系。结果表明,空气温度是决定生态系统呼吸和土壤呼吸变异的主导因子;生态系统呼吸、土壤呼吸以及裸地的土壤呼吸的Q10值分别为1.83～3.07、1.54～4.13和1.29～2.89;总体而言,生态系统呼吸和土壤呼吸Q10值随着海拔的升高和土壤水分含量的增加而增大。     

Development and application of cross-linked polyethylenimine for trace metal and metalloid removal from mining and industrial wastewaters

Pollution of water bodies by trace metals is an established problem and several studies have been conducted to deal with it. South Africa is amongst those countries whose water systems are most affected as a result of intensive mining activities. This research was dedicated to the development of an insoluble chelating polymer for use as an adsorbent for abstraction of metal ions from mining and industrial wastewaters. Polyethylenimine (PEI), well known for its metal chelating potential, was cross-linked by epichlorohydrin (ECH) in order to convert it into a water-insoluble form for direct use as an adsorbent. The binding affinity of the cross-linked polyethylenimine (CPEI) to heavy metal ions was assessed as well as its ability to be regenerated for re-use. CPEI exhibited good complexation ability to metal ions with high affinity to Cr and most divalent metal ions. The observed order of complexation was: Cr?>?Zn>?Fe?>?Ni?>?Mn?>?Pb. On the other hand, it showed very poor ability to bind oxo-anions such as SeO₃ ^2? and AsO₂ ^? which has been attributed to the unavailability of suitable functional groups to interact with these ions.     

Can a water market avert the “double-whammy” of trade reform and lead to a “win–win” outcome?

This paper focuses on the linkages between water and trade policies, using Morocco as a case. This country is typical of many in that policy protects its import competing agricultural and industrial sectors while water in irrigated agriculture is priced below its marginal value product. Changing water policy without correcting for these other distortions leads to a more inefficient allocation of water. On the other hand, reforming trade policy alone can make farmers growing crops protected pre-reform worse off. Using an intertemporal, applied general equilibrium model, we find that trade reform actually creates an opportunity to pursue water policy reform. Creating a water user-rights market post trade reform not only compensates for the decline in farmers’ profits caused by the trade reform, but also raises the efficiency of water allocation and hence benefits the economy as a whole.     

睾丸酮丛毛单胞菌对喹啉类化合物的降解

对喹啉、异喹啉、2-甲基喹啉、3-甲基喹啉、4-甲基喹啉和6-甲基喹啉在睾丸酮丝毛单胞菌(Comamonas testosteroni Q10)作用下的降解及底物之间的相互作用进行研究．结果表明,喹啉和3-甲基喹啉不仅能有效地被降解,而且细菌也有明显的生长,而其它化合物虽有部分降解但没有观察到细胞生长．底物初始浓度的增加对菌Q10有一定抑制作用．喹啉的存在对其它化合物的降解具有不同的促进效应,其中尤以6-甲基喹啉和4-甲基喹啉最为明显．能在较短时间内得到完全去除,而在各二元体系中喹啉的降解受到这些化合物的抑制作用．     

Hydrolysis of a model surfactant as measured using ACYL coenzyme a synthetase

Hydrolysis of a model nonionic surfactant, [1‐¹⁴C]methyl palmitate, was compared between porcine esterase and lipase using a new hydrolase assay. The assay incorporates acyl coenzyme A (CoA) synthetase to convert the hydrolytic product of methyl palmitate, palmitic acid, to its acyl CoA derivative; palmitoyl CoA is separated from unreacted substrate for quantitation by a highly efficient extraction. The assay achieves quantitative separation between product and substrate due to the high water solubility of the acyl CoA derivative, eliminating the need for time‐consuming chromatographic separations. After 60 min under optimal conditions, only 20 U/mL porcine hepatic esterase hydrolyzed 93.6+0.9% of 20μM methyl palmitate, while 100U/mL porcine pancreatic lipase was required to hydrolyze only 82.3 ±0.7% of the same substrate. While both enzymes detoxified the surfactant, esterase was more efficient, possibly indicating preferential specificity for simple monoesters; generally selective for endogenous triacylglycerols, lipase may be less specific for surfactants. However, together both enzymes may enable mammals to hydrolyze ingested nonionic surfactants from oil spill dispersants, reducing their toxicity.     

Fate of the veterinary medicine ivermectin in soil

We investigated the fate of the drug ivermectin in the soil. We found that ivermectin was transformed solely by photos, leading to the formation of two ivermectin isomers. We indeed failed to detect any biotransformation reaction of the chemical either in the soil or in fungal liquid cultures. According to its limited water solubility, the bioavailability of ivermectin was very low in the soil solution. Here, we show that ivermectin, transferred to the soil from faeces of drug-treated cattle, could be stored for long periods in the soil.     

纳米材料对玉米磷营养的影响初探

利用纳米材料处理水浇灌玉米(Zeamays),探讨了纳米材料对玉米磷营养的影响;用纳米材料处理水浸提磷矿粉,验证了纳米材料处理水对磷矿粉溶解性的促进作用。用纳米材料处理水浇灌玉米植株,可提高玉米的株高、茎粗以及生物量,使玉米植株地上部的氮磷钾的总量提高,同时可以提高植株中磷的含量7%~10%。取磷矿粉放于纳米材料处理水中,振荡、过滤,测定过滤液中的水溶性磷的含量,纳米材料可使磷矿粉浸提液中水溶性磷的含量较对照高20%~70%。利用纳米材料处理水提高磷矿的有效性,为提高磷的有效性、充分利用低品位磷矿提供了一条新的途径。     

Metallic nanoparticles: green synthesis and spectroscopic characterization

Metallic nanoparticles are finding new applications in medical, pharmaceutical, food and agriculture sectors. Applications include drug delivery, targeted cancer remedies, biomarker mapping, gene delivery and molecular imaging. This article reviews green strategies for the preparation of metallic nanoparticles, using enzymes, vitamins, monosaccharides, polysaccharides and biodegradable polymers. Microwave-assisted synthesis is detailed. Then, we review nanoparticle characterization using UV–visible spectroscopy and Fourier transform infrared spectroscopy. We also present applications for water purification.     

Drug delivery systems using pullulan,a biocompatible polysaccharide produced by fungal fermentation of starch

Environmental Chemistry Letters - Advanced drug delivery systems are now designed with biodegradable, biocompatible and non-toxic materials such as polysaccharides. Pullulan is a polysaccharide...     

Food webs supporting fish over subtropical mudflats are based on transported organic matter not in situ microalgae

We present here a morpho-functional and behavioural study of the feeding adaptations developed by a deep-sea invertebrate, the caprellid amphipod Parvipalpus major, in an environment temporarily deprived of external food supply. The animals were taken intact from bathyal muddy sediments using a classic Barnett multi-tub corer at depths ranging from 424 to 761 m. They were transferred to the laboratory, kept in tanks with their native sediment at a constant temperature (10°C) and their behaviour was studied by video analysis. Their morphology consists of elongated somites, with pereopods 5–7 ending in elongated curved dactyls, which are longer than those of more coastal species. Analysis of the literature shows that the largest caprellids inhabit the deepest and muddiest zones. This particular morpho-functional adaptation enables the species to adopt an originally erect and steady stance by fixing onto soft muddy sediment, thus improving its ability to prospect for food in its surrounding environment. For the most part, P. major balances its body at its anchorage point as it searches for food in the water column, but occasionally it bends down to the substrate, and tosses some sediment into the water column. Food is then selected from the particles that float down. Presumably, after exhausting the food supply in one area, the animal jumps into the water column and moves about a body length further on. This would appear to be an original strategy for foraging larger areas of organic matter from fixed, but temporary, positions. Finally, we show that caprellids are able to practise coprophagy. To conclude, we suggest that there is a positive correlation between body elongation and depth, with improved anchoring and coprophagy being an optimal way to conserve energy in conditions of limited diet and improve adaptation to life on deep-sea muddy bottoms.Communicated by S.A. Poulet, Roscoff