欧姆龙自动化解决方案及新产品巡展在京完美收官

<正> 欧姆龙 Compact Solution 2008春季巡展在历经了佛山、广州、东莞、深圳、温州、杭州,无锡、上海、大连、青岛、济南11站之后,最后一站来到京城,为用户带来更丰富的自动化产品以及解决方案。欧姆龙自动化的专家展示了"Compact Solution"在粉末灌装线、套标机、剪板机、磨床、卷布机、涂布机等领域的完整解     

酵母源金属硫蛋白对慢性汞中毒小鼠氧化损伤的修复作用

探讨具有自主知识产权的两种酵母源金属硫蛋白（metallothionein,MT）亚型（MT-1和MT-2）对慢性汞中毒小鼠氧化损伤的修复作用。实验小鼠经氯化汞染毒,连续灌胃两种酵母源MT及二巯基丙磺酸钠（dimercaptopropansulfonate sodium,DMPS）28 d后测定小鼠体质量、全血汞含量及血清超氧化物歧化酶（superoxide dismutase,SOD）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）活力,丙二醛（malondialdehyde,MDA）含量及机体总抗氧化能力（total antioxidative capacity,T-AOC）。与正常对照组小鼠相比,模型对照组小鼠体质量显著下降（P＜0.05）,灌胃给药28 d后,两种酵母源MT亚型高剂量组小鼠体质量显著升高（P＜0.05）;各给药组小鼠血液、肝脏及肾脏汞含量显著低于模型对照组（P＜0.05）,两种酵母源MT亚型高剂量组的排汞效果显著优于DMPS组（P＜0.05）;各给药组小鼠血清中GSH-Px、SOD活力和MDA水平及总抗氧化能力接近正常对照组小鼠水平（P＞0.05）,其中酵母源MT高剂量组的作用效果最佳,且在改善机体T-AOC方面的效果优于DMPS组（P＜0.05）,酵母源MT-1亚型升高小鼠血清SOD活力和降低血清MDA含量的作用效果明显好于酵母源MT-2亚型。两种酵母源MT对慢性汞中毒小鼠具有良好的氧化损伤保护作用及排汞效果。     

广东沿海两地海水鱼总汞与甲基汞的相关性分析

本研究以粤东和粤西两个渔村为研究区域,以两地20种主产海水鱼为研究对象,开展了海水鱼总汞和甲基汞的污染调查研究。通过直接测汞仪法和高效液相色谱-在线紫外消解-原子荧光光谱法研究了卵形鲳鯵、多鳞鱚和马鲛鱼等20种133尾海水鱼肌肉组织的总汞(total mercury,T-Hg)和甲基汞(methyl mercury,Me Hg)的总量与比值,结果显示:粤东某渔村海水鱼总汞含量为15.35~201.68 ng/g,甲基汞含量为8.32~200.20 ng/g,甲基汞含量所占总汞含量的比例平均为72.93%;粤西某渔村海水鱼总汞含量为11.32~156.00 ng/g,甲基汞含量为11.05~155.60 ng/g,甲基汞含量所占总汞含量的比例平均为83.39%。两渔村海水鱼汞含量均未超国标(GB 2762-2017)限量,而甲基汞在海水鱼肌肉中含量占总汞含量的比例平均值为76.45%,即甲基汞是汞在海水鱼肌肉中的主要赋存形态,海水鱼汞形态分布情况可能存在地域差异和品种差异。     

Calcium release from milk concentrated by ultrafiltration and diafiltration

The present work studied the solubilization of Ca during acidification in milk concentrated by ultrafiltration (UF) and diafiltration (DF). The effect of heating milk at 80°C for 15 min was also evaluated. In addition to measuring buffering capacity, the amount of Ca released as a function of pH was determined. The area of the maximum peak in buffering capacity observed at pH ~5.1, related to the presence of colloidal Ca phosphate, was significantly affected by casein volume fraction but did not increase proportionally with casein concentration. In addition, a lower buffering capacity and less solubilized Ca were measured in 2× DF milk compared with 2× UF milk. Heat treatment did not change the buffering capacity or Ca release in 1× and 2× concentrated milk. On the other hand, at a higher volume fraction (4×), more Ca was present in the soluble phase in heated 4× UF and DF milk compared with unheated milk. This is the first comprehensive study on the effect of concentration, distinguishing the effect of UF from that of DF, before and after heating, on Ca solubilization.     

酵母源金属硫蛋白对慢性汞中毒小鼠排汞及肝脏损伤修复作用

目的:探讨两种具自主知识产权酵母源金属硫蛋白(metallothionein,MT)(MT-1、MT-2)对慢性汞中毒小鼠排汞及汞致肝脏损伤的修复作用。方法:慢性汞中毒模型通过实验小鼠自由饮用氯化汞去离子水溶液构建,经连续灌胃给予二巯基丙磺酸钠及不同剂量酵母源MT(0.16、0.40、0.80 mg/(kg·d))28 d后,测定实验小鼠体质量、肝脏脏器系数、血液及肝脏汞含量、4项血常规(白细胞计数、红细胞计数、血小板计数、血红蛋白含量)、肝功能指示指标并观察慢性汞中毒小鼠肝脏组织病变程度。结果:与模型对照组比较,各灌胃给药组小鼠体质量均不同程度提高,肝脏脏器系数显著下降(P0.05),血液及肝脏汞含量显著下降(P0.05),白细胞、红细胞、血红蛋白含量及血小板计数均有不同程度恢复,其恢复效果与剂量呈正相关。与模型对照组比较,各酵母源MT灌胃给药组小鼠血清谷丙转氨酶及谷草转氨酶含量均有所下降,且综合肝脏组织病理学染色切片结果,酵母源MT可修复汞中毒小鼠肝脏组织,使水肿肝脏细胞恢复其正常形态,减少细胞间炎性浸润现象,且两种酵母源MT修复受损肝脏的能力与剂量呈正相关,高剂量酵母源MT对受损肝脏的修复效果更佳。结论:综合各项检测结果,两种酵母源MT对慢性汞中毒小鼠具有良好的排汞及修复汞致肝脏损伤效果,且酵母源MT-1对慢性汞中毒小鼠排汞及修复受损肝脏组织的效果好于酵母源MT-2及二巯基丙磺酸钠。     

高效液相色谱-原子荧光光谱联用法测定牛肝菌中无机汞、甲基汞、乙基汞的不确定度评估

采用高效液相色谱-原子荧光联用法测定牛肝菌中无机汞、甲基汞、乙基汞,通过建立评估的数学模型,分析不确定度的主要来源,计算出不确定度的各主要分量,得出合成不确定度和扩展不确定度。结果表明:影响结果不确定度的主要因素是浓度因素、仪器、样品不均匀性及回收率,其中浓度因素主要受标准曲线拟合的影响。该评估系统可为今后采用高效液相色谱-原子荧光联用法测定食用菌中无机汞、甲基汞、乙基汞的不确定度评估提供参考。     

Cycle development and design for CO2 capture from flue gas by vacuum swing adsorption

CO2 capture and storage is an important component in the development of clean power generation processes. One CO2 capture technology is gas-phase adsorption, specifically pressure (or vacuum) swing adsorption. The complexity of these processes makes evaluation and assessment of new adsorbents difficult and time-consuming. In this study, we have developed a simple model specifically targeted at CO2 capture by pressure swing adsorption and validated our model by comparison with data from a fully instrumented pilot-scale pressure swing adsorption process. The model captures nonisothermal effects as well as nonlinear adsorption and nitrogen coadsorption. Using the model and our apparatus, we have designed and studied a large number of cycles for CO2 capture. We demonstrate that by careful management of adsorption fronts and assembly of cycles based on understanding of the roles of individual steps, we are able to quickly assess the effect of adsorbents and process parameters on capture performance and identify optimal operating regimes and cycles. We recommend this approach in contrast to exhaustive parametric studies which tend to depend on specifics of the chosen cycle and adsorbent. We show that appropriate combinations of process steps can yield excellent process performance and demonstrate how the pressure drop, and heat loss, etc. affect process performance through their effect on adsorption fronts and profiles. Finally, cyclic temperature profiles along the adsorption column can be readily used to infer concentration profiles-this has proved to be a very useful tool in cyclic function definition. Our research reveals excellent promise for the application of pressure/vacuum swing adsorption technology in the arena of CO2 capture from flue gases.     

基于荧光原位杂交法剖析窖泥微生物的预处理条件探究及应用

该研究首先对浓香型白酒窖泥样品的料液比、离心转速、超声波分散时间、Al2（SO4）3添加量等预处理条件进行优化;然后将纯培养菌体添加到窖泥样品,采用荧光原位杂交（FISH）法检测菌体回收率;最后按最优预处理条件处理不同窖龄窖池窖泥,并采用FISH法研究窖泥样品中的微生物。结果表明,窖泥样品的最优预处理条件为料液比1∶16（g∶mL）、离心转速800 r/min、超声分散时间60 s、Al2（SO4）3添加量为4.17×10-5 mol/g窖泥。在此条件下,FISH法检测大肠杆菌（Escherichia coli）、植物乳杆菌（Lactobacillus plantarum）的菌体回收率分别为62.50%、55.44%,表明优化后的预处理条件对于窖泥微生物的FISH检测是可行的。FISH法检测窖泥微生物,结果显示随着窖池窖龄的增加,窖泥样品中细菌、古菌及菌体总数差异明显,总体呈现出先增加后降低的趋势,在100年窖龄的窖泥样品中,微生物总量最高。     

Enhanced copper release from pipes by alternating stagnation and flow events

Traditional studies of copper release in plumbing systems assume that the water extracted from a pipe follows a plug-type flow and that the pipe surface does not interact with the bulk water under flow conditions. We characterized actual stagnation-flushing cycles in a household pipe undergoing corrosion in the presence of a microbial biofilm. The mass of copper released in 10 experiments was on average 8 times the value estimated by using the plug-flow assumption. The experimental copper release pattern was explained by an advection-diffusion model only if a high copper concentration occurs near the pipe surface after stagnation. Microscopic examination of the pipe surface showed a complex assemblage of biotic and abiotic features. X-ray diffraction analyses identified only malachite, while X-ray absorption spectroscopy also revealed cupric hydroxide and cuprite. These results indicate that the surface serves as a storage compartment of labile copper that may be released under flow conditions. Thus, the diffusive transport from the pipe surface to the bulk during stagnation is not the only control of the flux of copper to the tap water when porous reactive microstructures cover the pipe. Our results highlight the need for models that consider the interaction between the hydrodynamics, chemistry, and structure at the solid-water interface to predict the release of corrosion byproducts into drinking water.     

电感耦合等离子体质谱法测定大米中的铅、镉、汞残留量研究

目的建立大米中铅、镉、汞的测定方法.方法采用电感耦合等离子体质谱(ICP-MS).结果在0～20 ng/ml范围内铅的浓度与响应值呈良好的线性关系(r=0.9983,n=5);平均回收率为109.3%,RSD=5.6%,(n=6).在0～10ng/ml范围内镉的浓度与响应值呈良好的线性关系(r=0.999998,n=5);平均回收率为99.2%,RSD=6.5%,(n=6).在0～5 ng/ml范围内汞的浓度与响应值呈良好的线性关系(r=0.99998,n=6);平均回收率为91.2%,RSD=7.3%,(n=6).结论本法简便、灵敏、准确.     

Mercury concentration in fish from streams and rivers throughout the western United States

We collected and analyzed 2,707 large fish from 626 stream/river sites in 12 western U.S. states using a probability design to assess the regional distribution of whole fish mercury (Hg) concentrations. Large (>120 mm total length) fish Hg levels were strongly related to both fish length and trophic guild. All large fish that we sampled exceeded the wet weight detection limit of 0.0024 microgxg(-1), and the mean Hg concentration in piscivores (0.260 /microgxg(-1)) was nearly three times that of nonpiscivores (0.090 microgxg(-1)). Fish tissue Hg levels were not related to local site disturbance class. After partialing out the effects of fish length, correlations between Hg and environmental variables were low (r < 0.3) for the most common genera (trout and suckers). Stronger partial correlations with Hg (r > 0.5) were observed in other genera for pH, stream size, and human population density but patterns were not consistent across genera. Salmonids, the most common family, were observed in an estimated 125,000 km of stream length, exceeded 0.1 microg Hg x g(-1) (deemed protective for fish-eating mammals) in 11% of the assessed stream length, and exceeded the filet equivalent of 0.3 microg Hgxg (-1) (USEPA tissue-based water quality criterion) in 2.3% of that length. Piscivores were less widespread (31,400 km), but they exceeded the 0.1 and 0.3 microg Hgxg(-1) criteria in 93% and 57% of their assessed stream length, respectively. Our findings suggest that atmospheric transport is a key factor relative to Hg in fish across the western United States.     

Mercury reduction and oxidation by reduced natural organic matter in anoxic environments

Natural organic matter (NOM)-mediated redox cycling of elemental mercury Hg(0) and mercuric Hg(II) is critically important in affecting inorganic mercury transformation and bioavailability. However, these processes are not well understood, particularly in anoxic water and sediments where NOM can be reduced and toxic methylmercury is formed. We show that under dark anoxic conditions reduced organic matter (NOM(re)) simultaneously reduces and oxidizes Hg via different reaction mechanisms. Reduction of Hg(II) is primarily caused by reduced quinones. However, Hg(0) oxidation is controlled by thiol functional groups via oxidative complexation, which is demonstrated by the oxidation of Hg(0) by low-molecular-weight thiol compounds, glutathione, and mercaptoacetic acid, under reducing conditions. Depending on the NOM source, oxidation state, and NOM:Hg ratio, NOM reduces Hg(II) at initial rates ranging from 0.4 to 5.5 h(-1), which are about 2 to 6 times higher than those observed for photochemical reduction of Hg(II) in open surface waters. However, rapid reduction of Hg(II) by NOM(re) can be offset by oxidation of Hg(0) with an estimated initial rate as high as 5.4 h(-1). This dual role of NOM(re) is expected to strongly influence the availability of reactive Hg and thus to have important implications for microbial uptake and methylation in anoxic environments.     

Improved detection of Salmonella spp. in foods by fluorescent in situ hybridization with 23S rRNA probes: a comparison with conventional culture methods

This report describes a new technique for the detection and identification of Salmonella species in food with the use of fluorescent in situ hybridization (FISH) with 23S rRNA-targeted oligonucleotide probes. Two species-specific 23S rRNA-targeted oligonucleotide probes (Sal-1 and Sal-3) were selected, and one (Sal-544) was newly designed. The relative specificities of these probes were compared with those of bacterial 23S rRNA sequences from the GenBank database and tested by in situ hybridization with bacterial cell smears of pure cultures. Fifty-one tested reference strains of Salmonella serovars belonging to subspecies I (enterica) hybridized with these probes. No cross-reactions with 46 other strains of the family Enterobacteriaceae or with another 14 bacterial strains from other families were observed. Storage of a Salmonella Panama test strain under various environmental conditions (2, 5, and 15% NaC1; -20 degrees C, 4 degrees C, and room temperature; pHs of 3.3 to 7.4) did not adversely affect the FISH method. No matrix effects were observed with 18 different kinds of foods. FISH was able to detect Salmonella spp. in 52 (probe Sal-1), 56 (probe Sal-3), and 35 (probe Sal-544) of 225 naturally contaminated food samples after 16 h of incubation in a preenrichment broth. When conventional culture and detection methods were used, Salmonella could be isolated from only 30 of these 225 samples. In contrast, FISH failed to identify Salmonella in only two of the culture-positive samples when Sal-1 and Sal-3 were used and in only three of the culture-positive samples when Sal-544 was used.     

全自动测汞仪和原子荧光光谱仪测定竹荪中总汞含量不确定度的比较

采用全自动测汞仪和原子荧光光谱仪分别测定了竹荪中总汞的含量。通过建立数学模型,全面地分析不确定度的主要来源,计算出不确定度的各个分量,得出合成不确定度和扩展不确定度,并对评估结果进行比较。结果表明:当总汞的测定结果为0.050 mg/kg时,两种方法的扩展不确定度分别为0.006、0.002 mg/kg（k=2）。本方法可为今后采用全自动测汞仪和原子荧光光谱仪测定食用菌中总汞的不确定度评估提供参考。     

Nisin release from films is affected by both protein type and film-forming method

Effects of protein type (wheat or corn) and film-forming method (casting or heat-pressing) on films were evaluated for the retention of biologically active nisin (Nisaplin) and release of activity into water at four different temperatures (5, 25, 35 and 45 °C). Nisin activity was measured using the agar diffusion method against Lactobacillus plantarum 1752. Cast corn zein (CCZ) and cast wheat gluten (CWG) films retained 12.1% (8.1×10⁴ IU/g film) and 15.8% (1.1×10⁵ IU/g film) of the original activity after film formation, respectively. Heat-pressed corn zein (HPCZ) and heat-pressed wheat gluten (HPWG) films retained 6.5% (4.3×10⁴ IU/g film) and 7.4% (4. 9×10⁴ IU/g film) of the original activity after film formation, respectively. The maximum nisin activity found migrating into water at any sampling time was 561 IU/ml (CCZ), 1058 IU/ml (CWG), 309 IU/ml (HPCZ), and 478 IU/ml (HPWG).     

Food contamination by hydrocarbons from lubricating oils and release agents: determination by coupled LC-GC.

We have found that many foods are contaminated with mineral oil products used as lubricating oils/greases or as release agents. The mineral oil base of such products usually consists of branched alkanes ranging between C17 and C35. It forms a broad 'hump' of unresolved compounds in the gas chromatogram. Examples of such products are described; contamination is shown for a sample of bread, bonbon, and chocolate, respectively. The results suggest that contamination of foodstuffs with mineral oils does not always receive the required attention. However, there is also a lack of guidelines.     

Mercury, arsenic, lead and cadmium in fish and shellfish from the Adriatic Sea

The aim was to measure concentrations of total mercury, total arsenic, lead and cadmium in common edible fresh fish and shellfish from various areas of the Adriatic Sea. Estimates of intake of these elements were made through seafood consumption by the general population. Samples were either wet digested for mercury and arsenic, or dry ashed for lead and cadmium analysis. Mercury was measured by cold vapour atomic absorption spectrometry (CV AAS) and arsenic, lead and cadmium by electrothermal atomic absorption spectrometry (ET AAS). Quality control procedures of analytical methods, which included analyses of dogfish muscle-certified reference material DORM-2, confirmed the acceptability of methods. The highest mercury and arsenic concentrations were found in hake ( Merluccius merluccius ) and the lowest in mackerel ( Scomber scombrus ). The respective values in hake were 0.373 ±0.075 and 23.3 ±3.6, and in mackerel 0.153 ±0.028 and 1.06 ±0.29 mg kg -1 fresh weight (mean ±SD). Lead and cadmium concentrations were about 10 times higher in shellfish than in analysed fish. The highest lead and cadmium concentrations were found in mussel ( Mytilus galloprovincialis ) and the lowest in hake. Respective lead and cadmium values in mussel were 0.150 ±0.009 and 0.142 ±0.017, and in hake were 0.007 ±0.004 and 0.002 ±0.001 mg kg -1 fresh weight. The concentrations of analysed elements were below acceptable levels for human consumption set by the Croatian Ministry of Health, except for total arsenic. The estimated intake of those trace elements included in this study through seafood consumption by the general population did not exceed the provisional tolerable weekly intake recommended by the Joint FAO/WHO Expert Committee on Food Additives.