抗肝癌hdsFv-hEDN重组免疫毒素的表达及生物学活性

目的制备对人肝癌细胞具有特异性杀伤活性的抗肝癌重组免疫毒素。方法利用大肠杆菌系统表达抗肝癌hdsFvhEDN基因重组免疫毒素。表达产物经NiNTA亲和层析纯化后,进行特异性杀伤活性检测。结果抗肝癌hdsFvhEDN重组免疫毒素以可溶性形式表达于大肠杆菌培养上清中,并获得有效纯化。ELISA法检测证实其具有与相应抗原特异性结合的活性。细胞毒试验表明对肝癌细胞具有杀伤作用,而对正常肝细胞无损伤。结论已成功地制备了具有特异性结合和杀伤活性的抗肝癌hdsFvhEDN基因重组免疫毒素,为其进一步应用奠定基础。     

Stimulating Biological Nitrification via Electrolytic Oxygenation

The feasibility of electric current prompted aerobic biodegradation of NH4+–N in an attached growth bioreactor system is demonstrated. Nitrification was induced at electric current densities of 1.25 and 2.5?mA/cm2 and with pure oxygen supplied at a rate equivalent to 1.25?mA/cm2 when the bioreactor was operated in batch mode at 6 days detention time. About 84% (27?mg/L)?NH4+–N loss was observed at the end of each detention period during all three experimental conditions, indicating that the electric current did not negatively impact the rate of nitrification. Nitrite accumulation was observed during the initial stages of nitrification experiments with 1.25?mA/cm2 current intensity, but nitrite did not accumulate during the other two sets of nitrification experiments. A mathematical model formulated to obtain the rates of biological reactions showed that rates of NH4+–N removal are similar for all aeration conditions. Abiotic experiments showed that NH4+–N was not removed electrolytically and via stripping, confirming that NH4+–N disappearance is due to biological activity.     

表征PAN纤维和炭纤维微细结构的HRTEM样品制备方法

为用高分辨透射电子显微术(HRTEM)表征聚丙烯腈(PAN)纤维和炭纤维的微细结构，从纤维性能出发，探讨研碎、离子束减薄和超薄生物切片三种制备方法及其工艺步骤，结合实验结果，对比了三种制备方法的原理、优缺点，提出了制备方法的适用范围和选择原则，并推断适于表征预氧化纤维微细结构的样品制备方法。与生物样品的制备方法类似，把超薄生物切片法引入到纤维材料HRTEM样品制备领域，为系统研究炭纤维微细结构的演变提供了线索。     

辐射防护的生物学基础--辐射生物效应

人类必须研究电离辐射的生物效应，以保护其自身及其它物种免受电离辐射的有害影响，同时在应用中最大限度地获取利益，辐射生物效应，作为辐射防护的生物学基础，一直受到国内外辐射防护界的极大关注。本文就辐射防护密切相关的辐射随机效应，辐射致癌概率，小剂量照射效应及组织权重因子等进行简要讨论。     

辐射的低剂量生物效应及分子流行病学研究现状

对低剂量辐射效应研究中的主要问题，诸如线性无阈假设、辐射致癌危险评价、辐射致癌机理以及辐射旁效应进行了综述，并概要介绍了分子流行病学在辐射效应研究中的应用及其研究现状。     

Conversion of Full-Scale Wet Scrubbers to Biotrickling Filters for H2S Control at Publicly Owned Treatment Works

Until recently, biological treatment of odors in biofilters or biotrickling filters was thought to require a longer gas contact time than chemical scrubbing, hence bioreactors for air treatment required a larger footprint. This paper discusses the conversion of chemical scrubbers to biological trickling filters. Initially, research was conducted with a laboratory-scale biotrickling filter. An effective open-pore polyurethane packing material was identified and H2S biotreatment performance was quantified. Key technical issues in determining the general suitability of converting wet scrubbers to biotrickling filters were identified, and a generic ten-step conversion procedure was developed. Following the laboratory research, five full-scale chemical scrubbers treating odorous air at the Sanitation District of Orange County, Calif., were converted to biotrickling filters. The original airflow rate was maintained, resulting in a gas contact time as low as 1.6–3.1?s. The converted biotrickling filters demonstrated an excellent capability for treating high H2S concentrations to concentrations below regulatory limits. This study shows outstanding potential for converting chemical scrubbers to biotrickling filters at publicly owned treatment works.     

Influence of Sodium Dodecyl Sulfate and Tween 20 on Fungal Growth and Toluene Degradation in a Vapor-Phase Bioreactor

Biofiltration, a process in which contaminated air is passed through a biologically active bed, can be used to remove volatile organic pollutants from air streams. While most biofilters rely on bacteria to degrade organic pollutants, biofilters utilizing a fungal biofilm have the potential to be an efficient and robust treatment alternative. In this study, two surfactants were evaluated for their ability to activate the spores of the fungus Exophiala lecanii-corni and reduce the start-up period typically observed in fungal vapor-phase bioreactors. Sodium dodecyl sulfate, an anionic surfactant, was found to inhibit growth of E. lecanii-corni. Polyoxyethylene sorbitan monolaurate (Tween 20), a nonionic surfactant, stimulated bud formation and enhanced toluene degradation in E. lecanii-corni cultures. Tween 20 was also found to enhance inoculum development by shortening the lag period during culture growth. However, when bioreactors were presoaked in medium containing Tween 20, washout of the fungal cells occurred during inoculation, inhibiting the initial fungal biofilm development. After a seven-day start-up period, no detrimental effects on reactor performance due to residual Tween 20 were observed, and toluene elimination capacities of up to 150?g/m3?h were achieved.     

Improved Anaerobic Process Efficiency Using Mesophilic and Thermophilic Elutriated Phased Treatment

An innovative anaerobic digestion elutriated phased treatment (ADEPT) has been evaluated at mesophilic (M-ADEPT) (35°C) and thermophilic (T-ADEPT) (55°C) temperatures in which the organic loading rate (OLR) was increased until reactor failure (pH<5.5). Single-stage continuously stirred tank reactors (CSTRs) at both temperatures were also operated as controls (M-CSTR for 35°C and T-CSTR for 55°C). The T-CSTR failed at an OLR of 7.4 g volatile solid (VS)/L?day and the M-CSTR at an OLR of 10 g VS/L?day while the M-ADEPT continued until an OLR of 18 g VS/L?day and the T-ADEPT reached an OLR of 24 g VS/L?day before system failure. The T-CSTR produced the poorest effluent quality as manifested by high propionate concentrations (1,500–2,500 mg/L) while both M-ADEPT and T-ADEPT produced much better quality of effluent with propionate concentrations below 100 mg/L. Thus it appears that the T-ADEPT design may solve effluent quality problems associated with normally high propionate concentrations produced during thermophilic anaerobic digestion. Superior effluent quality, reduced reactor volume requirements, more stable methanogenesis due to the extended solids retention time, and uncoupling of the methanogen wasting from the refractory sludge wasting process resulted in stable and efficient processing at both temperatures for the innovative ADEPT design. Because the higher amounts of volatile fatty acids produced in the acid elutriation phase of the ADEPT system can be a favorable carbon source for biological nutrient removal in wastewater treatment plants, this positive aspect should be considered in future applications of the ADEPT system.     

Engineering Aspects of the Integration of Chemical and Biological Oxidation: Simple Mechanistic Models for the Oxidation Treatment

Oxidation processes can oxidize biorecalcitrant compounds into biodegradable intermediates, which in turn can be treated less expensively by a subsequent biological process. To design such a two-step (chemical+biological) process to treat poorly characterized wastewaters, it is useful to model the time evolution of characteristic global variables, chemical oxygen demand (COD) and biochemical oxygen demand (BOD), in order to develop a useful treatment strategy based upon these classical variables. We consider two simple model reaction networks, requiring three- and five-rate constants, respectively. The first model, proposed recently, involves conversion of a nonbiodegradable species, C, into a single biodegradable intermediate S. Here, biodegradable compounds are immediate kinetic products of oxidation. In general, it is not probable that a single recalcitrant compound undergoes a single-step reaction to CO2. However, when working with complex undefined wastewaters streams, single-step reactions may be used to simplify. The second new model corresponds to a lag time in BOD formation due to the necessity of multiple partial oxidations to reach a first biodegradable intermediate. The second network includes two intermediates, I and S, which are, respectively, nonbiodegradable and biodegradable. We then compare model behavior with an unfortunately sparse literature on BOD and COD values versus time in chemical reactors, and demonstrate the convenience of the first model, and the occasional necessity of the second, which reflects the presence of early intermediates which are nonbiodegradable.     

土壤养分有效性测定及其方法

在提出土壤养分有效性测定概念的基础上 ,本文对各种土壤养分有效性的测定方法进行了总结 ,讨论了这些方法的测定机理、测定效果及近几年的进展。这些方法包括用于磷钾等元素测定的树脂法、用于氮测定的生物培养法和化学提取法、磷测定的氧化铁试纸法和氢氧化铁透析管法和钾的四苯硼钠法