Production of phthalate esters by nuisance freshwater algae and cyanobacteria

Phthalate esters are widely distributed pollutants which originate from synthetic plasticizer and are known to act as toxicants as well as environmental pheromones in the aquatic ecosystems. From investigating sixteen species of freshwater algae and cyanobacteria we revealed that some of them were capable of producing either di(n-butyl)phthalate (DBP) or mono(2-ethylhexyl)phthalate (MEHP) or both. These phthalate esters would be released into the environment under stress conditions. The incubation of the cells in culture medium containing NaH¹³CO₃ confirmed that both phthalates were de novo synthesized by the studied cells. This study suggested that the nuisance freshwater micro-algae and cyanobacteria growing in eutrophic waters might affect the aquatic ecosystem via the production of these phthalate esters.     

同位素分析法在三山岛金矿的应用

三山岛矿区地下水质有海水、第四系水、基裂岩隙水、地下热水、淡水等。为了适应矿区生产的需要,需对水质进行分析。但是,常规的水质简分析法只能鉴别水的类型,不能提供其它资料,为此采用同位素分析法。该法不仅能验证水文地质研究提供的结果,还能提供水文地质研究不易取得的数据与资料,如地下水相对停留时间,不同成因不同成分的地下水补给源的补给量及其比例。     

Investigation of the geographical provenance of the beer available in South Korea using multielements and isotopes

Although beer has the largest share of the global alcoholic beverage market, only limited studies of beer have been performed in terms of elemental and isotopic compositions. Here, we measured elemental and isotopic compositions—including carbon and oxygen isotopes as well as ⁸⁷Sr/⁸⁶Sr ratios—of beers available in South Korea to examine geographical differences. Although most of the elements analyzed in this study were not markedly different between the beer samples, there was a clear distinction in the isotopic compositions of the samples. δ¹³C_DIC values indicated that most of the beer samples were produced from C₃ plants, such as barley or wheat. δ¹⁸O values allowed the samples to be discriminated by latitude, reflecting a negative correlation between latitude and isotopic composition. Similarly, ⁸⁷Sr/⁸⁶Sr ratios were different between the samples due to the bedrock. Statistical analysis of the combination of elemental and isotopic compositions showed a clear difference between the beer samples according to the geographical provenance on a continental scale. This study demonstrated a powerful method for distinguishing diverse beers according to their geographical provenance, and will make an important contribution to research into discrimination of the geographical origin of diverse processed foods available commercially.     

Computational Fluid Dynamics Simulation of 13CO Distillation in Structured Packing

Physical 3D models were established for corrugated packing used in the enrichment of the isotope ¹³C. Computational fluid dynamics (CFD) simulation results indicated that common corrugated packing was not well wetted when used for isotope distillation. It is concluded that liquid misdistribution in the packed tower results from the structure of the packing rather than from the height of the packing beds. The existence of entrainment was also demonstrated by CFD simulation. It is proved that mass transfer equations based on the Nusselt theory are not suitable for distillation calculation in such a corrugated packing system. By comparison, the recently developed structured packing model with a corrugation geometry based on the right‐angled triangle, known as Zigzag‐pak, describes vapor‐liquid distribution properties well and has significant advantages over common corrugated packing due to its better liquid distribution character.     

甘肃天水宽沟金矿床同位素地球化学特征研究

通过对李子园地区宽沟金矿床氢、氧、硫、铅同位素特征的分析研究,讨论了该矿区成矿流体性质、来源及成矿物质来源等问题。氢氧同位素结果表明,宽沟金矿床成矿流体是一种混合源,以岩浆热液为主,有部分大气降水和变质热液的混入。硫同位素组成表明, 宽沟金矿床矿石硫以岩浆硫为主,同时混入了地层中的硫。铅同位素组成表明,成矿物质主要来源于深部的下地壳和上地幔,为壳幔混源,在成矿流体向上运移的过程中,有地层铅的混入,成矿与燕山期石英正长岩体关系密切。     

Intrinsic isotopic C labelling of polyphenols

The intrinsic isotopic labelling of plants with ¹³CO₂ is an effective method to generate highly labelled compounds using photosynthesis and avoiding labour-intensive complex organic syntheses. In this study, the intrinsic isotopic labelling of polyphenols in parsley, spinach and peppermint is shown for the first time. The plants were grown in an atmosphere where ¹²CO₂ was replaced by ¹³CO₂, in order to generate highly labelled compounds. The total content of ¹³C as well as the individual polyphenols were analysed by Isotopic Ratio-MS and HPLC–Iontrap-MSⁿ.     

SEPARATION OF STABLE NITROGEN ISOTOPES BY ION EXCHANGE CHROMATOGRAPHY

ABSTRACT

The ion exchange chromatography technique was used for the enrichment of nitrogen 15 (¹⁵N). A set of columns filled with the ion exchange resin Wofatit KPS (medium porosity type) with 5.4?cm I.D. and 1.5?m height was set up. Ammonia NH₄ ⁺/NH₃ aq. was chosen as the isotopic exchange system. The ammonium bands formed in the columns were eluted by a solution of sodium hydroxide. The isotope separation factor, ?, was found to decrease with increasing temperature or ammonia concentration. Operational conditions of temperature and ammonium concentration were proposed as the optimum for the production of the enriched isotope by using the present process. Results showed that: (1) the rear part of the band is enriched in ¹⁵N, while the frontal part is depleted; (2) it is possible to obtain 7.6?at. % of ¹⁵N after a 60?m displacement of the ammonium band. The analytical determination of the samples was made by emission spectrometry (NOI-6E).     

辐射伏特效应同位素电池换能单元的初步设计

初步设计制作3种辐射伏特效应同位素电池换能单元,测试其在固态63Ni源和3H源辐照下的输出电特性,对输出电特性进行数学解析模型分析并提出进一步改进设计的思路。结果表明,设计的换能单元在发射高能α同位素作用下,性能快速急剧退化;在2.96×108Bq的63Ni源辐照下,获得最大短路电流为28.4nA,最大开路电压为0.267V;在约5.09×109Bq的3H源辐照下,获得最大短路电流为62.8nA,最大开路电压为0.260V。当前换能单元参数还需进一步优化。     

MCNPX Monte Carlo burnup simulations of the isotope correlation experiments in the NPP Obrigheim

This paper describes the simulation work of the Isotope Correlation Experiment (ICE) using the MCNPX Monte Carlo computer code package. The Monte Carlo simulation results are compared with the ICE-Experimental measurements for burnup up to 30 GWD/t. The comparison shows the good capabilities of the MCNPX computer code package for predicting the depletion of the uranium fuel and the buildup of the plutonium isotopes in a PWR thermal reactor. The Monte Carlo simulation results show also good agreements with the experimental data for calculating several long-lived and stable fission products. However, for the americium and curium actinides, it is difficult to judge the predication capabilities for these actinides due to the large uncertainties in the ICE-Experimental data. In the MCNPX numerical simulations, a pin cell model is utilized to simulate the fuel lattice of the nuclear power reactor. Temperature dependent libraries based on JEFF3.1 nuclear data files are utilized for the calculations. In addition, temperature dependent libraries based ENDF/B-VII nuclear data files are utilized and the obtained results are very close to the JEFF3.1 results, except for ∼10% differences in the prediction of the minor actinide isotopes buildup.     

基于稳定同位素技术的4种食源致病菌蛋白质组研究进展

目前微生物蛋白质组差异比较研究的最大困难在于无法获得稳定的内参照。而稳定同位素与其同位素存在质量差异,又不具有放射性,因此是分子差异比较研究的最理想的内参照,其作用是校正实验过程中存在的误差,保证实验结果的准确性。稳定同位素技术结合质谱分析的目标是:建立微生物(主要是致病菌)的稳定同位素体内标记技术并将标记产物作为内标用于微生物蛋白质组表达差异的研究,根据获得的差异信息为特殊处理条件下微生物的检测提供解决办法。本文从稳定同位素国内外研究进展、传统经典蛋白质组研究方法存在的不足和常见的4种食源性致病菌,包括沙门氏菌、单核增生李斯特氏菌、霍乱弧菌和副溶血弧菌的蛋白质组研究,并对副溶血性弧菌的蛋白质组研究作详细阐述。最后阐述稳定同位素标记的蛋白质组定量方法存在的一些挑战和今后的努力改进和发展的方向。