Asymmetric hydrogenation using modified ion exchange resin-palladium catalysts

The Science of Nature -     

Bacterial communities in different locations, seasons and segments of a dairy wastewater treatment system consisting of six segments

A dairy wastewater treatment system composed of the 1st segment (no aeration) equipped with a facility for the destruction of milk fat particles, four successive aerobic treatment segments with activated sludge and a final sludge settlement segment was developed. The activated sludge is circulated through the six segments by settling sediments (activated sludge) in the 6th segment and sending the sediments beck to the 1st and 2nd segments. Microbiota was examined using samples from the non-aerated 1st and aerated 2nd segments obtained from two farms using the same system in summer or winter. Principal component analysis showed that the change in microbiota from the 1st to 2nd segments concomitant with effective wastewater treatment is affected by the concentrations of activated sludge and organic matter (biological oxygen demand [BOD]), and dissolved oxygen (DO) content. Microbiota from five segments (1st and four successive aerobic segments) in one location was also examined. Although the activated sludge is circulating throughout all the segments, microbiota fluctuation was observed. The observed successive changes in microbiota reflected the changes in the concentrations of organic matter and other physicochemical conditions (such as DO), suggesting that the microbiota is flexibly changeable depending on the environmental condition in the segments. The genera Dechloromonas, Zoogloea and Leptothrix are frequently observed in this wastewater treatment system throughout the analyses of microbiota in this study.     

绿色生产力:一个亚洲可持续发展的手段

绿色生产力的概念是由亚洲生产力组织(APO)提出的.绿色生产力是一种提高生产率和环境性能的战略.它的目的是要确保社会-经济的均衡发展,使得人类生活质量能够可持续性改善.在提高获利性和竞争优势的同时,运用适当的生产力与环境管理手段、技术和工艺,能够降低团体活动、产品和服务所造成的环境影响.利益相关者群体(包括政府、工业界和学术界)提出了改革建议,就是希望能够得到更大的可持续能力.     

Designing a purification process for chromium-, copper- and arsenic-contaminated wood

The disposal of chromated copper arsenate (CCA)-treated wood is becoming a serious problem in many countries due to increasing levels of contamination by the hazardous elements, chromium, copper and arsenic. The present experiment was conducted as a preliminary step toward one-step solvent extraction of CCA-treated wood. Because chromium, copper and arsenic have different chemical characteristics, it is best to consider them separately prior to designing a one-step extraction process. As a basis, various two-step extraction processes were first designed and tested experimentally to determine feasibility. Among these combinations, the treatment combining oxalic acid as the 1st step and a sodium oxalate solution under acidic conditions (pH 3.2) as the 2nd step was found to be an effective way of extracting CCA elements from treated wood. Extraction efficiency reached 100% for arsenic and chromium and 95.8% for copper after a 3-h sodium oxalate treatment, following a 1-h pre-extraction process with oxalic acid. On the other hand, the same combination under alkaline conditions (pH 11.2) during the 2nd step was ineffective for copper removal, indicating that pH plays an important role in complexation with sodium oxalate solution. The present results suggest that the extraction of CCA elements using a combination of oxalic acid and acidic sodium oxalate solution is a promising basis for application to a one-step extraction method.     

Removal of arsenic from wastewater using iron compound: Comparing two different types of adsorbents in the context of LCA

A study was carried out in order to compare the environmental performance of two different types of adsorbents in removing arsenic (As) from wastewater. A FeCl₃-based adsorbent and a poly-Fe-based adsorbent were first synthesized and their abilities in adsorbing As from wastewater were investigated in terms of the adsorption density and the rate of adsorption. Here, it should be noted that the main material being used in the synthesis of the poly-Fe-based adsorbent was a waste product, known as polyferric sulfate or poly-Fe in short, which exits the manufacturing process of titanium dioxide.Both adsorbents were then compared in the context of life-cycle assessment (LCA). In other words, the experimental results (i.e. the value of the adsorption density and the rate of adsorption) were input into the LCA model in order to assess the environmental performance of each adsorbent in removing arsenic. An estimate for the environmental burden of each option was finally calculated as the sum of the depletion of abiotic resources (ADP), the global warming potential (GWP), the acidification potential (AP), the photo-oxidant formation potential (POCP), the eutrophication potential (EP), and the human toxicity potential (HTP). The main finding of this study was that the adsorption of arsenic by using the poly-Fe-based adsorbent is more attractive treatment option in the environmental protection point of view than the adsorption by using the FeCl₃-based adsorbent, which generates a relatively larger environmental burden.     

基于Logistic回归的燃气管网风险因素重要度分析方法研究

为确定燃气管网风险评估的关键风险因素,以A省各地市燃气管网为研究对象,基于燃气专家经验确定燃气管线风险等级,提出基于Logistic回归的燃气管网风险因素重要度分析方法。采用样本增强及随机抽样的方式,选取400个均衡样本作为管网评估数据输入,通过因子分析方法对其进行降维,得到3个公共因子并作为一级指标反向构建燃气管网风险评估指标体系;利用有序多分类Logistic回归方法,根据回归系数绝对值大小对风险因素进行重要度排序。研究结果表明：外界环境对燃气管网风险的贡献程度相对较高,管道自身因素和巡检养护次之。研究结果可为城市燃气风险防控提供理论依据和方法参考。     

Study on 14C-BHA absorption and distribution in rat

BHA was administered to rats at doses of 5 or 500 mg/kg for seven days. ¹⁴C-BHA absorption was investigated on the eighth day and compared with animals receiving a single dose of 5 or 500 mg/kg BHA. Absorption of ¹⁴C-BHA was proportionately greater at the high dose rats. ¹⁴C distribution was 3–6 times higher in the forestomach than in the pyloric region of the stomach. The urinary excretion of BHA conjugates was not dependent on pretreatment with BHA or on the dose.     

Fungal levels in houses in the Fukushima Daiichi Nuclear Power Plant evacuation zone after the Great East Japan Earthquake

Residences located within 20 km of the damaged Fukushima Daiichi Nuclear Power Plant were evacuated shortly after the Great East Japan Earthquake. The levels of airborne and surface fungi were measured in six houses in the evacuation zone in August 2012 and February 2013. Airborne fungal levels in all of the houses in the summer were higher than the environmental standard levels for residential houses published in Architectural Institute of Japan (>1000 colony-forming units [CFU]/m³). In two houses whose residents rarely returned to visit, fungal levels were extremely high (>52,000 CFU/m³). Although fungal levels in the winter were much lower than those in the summer, they were still higher than environmental standard levels in several houses. Indoor fungal levels were significantly inversely related to the frequency with which residents returned, but they were not correlated with the air exchange rates, temperature, humidity, or radiation levels. Cladosporium spp. and Penicillium spp. were detected in every house. Aspergillus section Circumdati (Aspergillus ochraceus group) was also detected in several houses. These fungi produced ochratoxin A and ochratoxin B, which have nephrotoxic and carcinogenic potential. The present study suggests that further monitoring of fungal levels is necessary in houses in the Fukushima Daiichi Nuclear Power Plant evacuation zone, and that some houses may require fungal disinfection.

Implications: The results suggest that residents’ health could be at risk owing to the high levels of airborne fungi and toxic fungi Aspergillus section Circumdati. Therefore, monitoring and decontamination/disinfection of fungi are strongly recommended before residents are allowed to return permanently to their homes. In addition, returning to home with a certain frequency and adequate ventilation are necessary during similar situations, e.g., when residents cannot stay in their homes for a long period, because fungal levels in houses in the Fukushima Daiichi Nuclear Power Plant evacuation zone were inversely correlated with the frequency with which residents returned to visit their houses.     

Sensitivity of gametes, fertilization, and embryo development of the Japanese pearl oyster, Pinctada fucata martensii, to the harmful dinoflagellate, Heterocapsa circularisquama

Blooms of the toxic dinoflagellate Heterocapsa circularisquama cause massive bivalve kills in Japan. Mariculture of the Japanese pearl oyster, Pinctada fucata martensii, is the industry most affected by these blooms, especially in Ago Bay, Mie Prefecture, where they are frequent, cause mass mortality of oysters, and overlap with their spawning season. The goal of this August 2009 study was to assess the effects of a toxic strain of H. circularisquama isolated from Ago Bay on gametes, fertilization, and embryo development of pearl oysters. Spermatozoa, eggs, spermatozoa and eggs, and fertilized eggs of pearl oysters from Ago Bay were exposed to H. circularisquama at cell densities reported during the bloom (10–10⁴ cells mL^?1) for different periods of time. The concentration of H. circularisquama, exposure duration, and their interactions all had significant effects on gamete quality, fertilization, and embryo development. The motility and swimming velocity of spermatozoa, egg viability, fertilization, and embryo development rate were significantly reduced in all concentrations, with a cell density of 10 cells mL^?1 determined to be the critical density of H. circularisquama for deleterious effects. This is the first evidence of inimical effects of an HAB species on bivalve spermatozoa upon direct exposure. Further field and laboratory studies are required to investigate the potential effects of H. circularisquama blooms on the reproduction and recruitment of Japanese pearl oysters and other bivalves.