产絮凝剂菌株发酵工艺的优化

目的 研究产絮凝剂菌株B5的最佳培养基组成和最佳发酵条件.方法 通过单因子实验研究不动杆菌B5(Acinetobacter sp.B5)产絮凝剂的最佳碳源、氮源和无机盐,并通过正交设计实验确定菌株B5产絮凝剂的最佳条件.结果 培养基的最佳碳源、氮源和无机盐分别为葡萄糖、硫酸铵和CaCl2,葡萄糖含量为2.0%,初始pH值为7.0,培养温度为30℃,摇床转速为160 r/min,培养时间为24 h,装液量为50 ml(250 ml三角瓶),接种量为0.2 ml时,絮凝率最高(76.85%).采用在最佳发酵条件下菌株B5的发酵液处理乳品厂废水、生活污水、印染厂废水等废水样品的絮凝率为88.4%～97.2%,其中,以对乳品厂废水的絮凝率最高(97.2%).可见菌株B5的发酵液对乳品厂废水和生活废水的絮凝效果较好.结论 菌株B5产生的絮凝剂可有效地处理各类废水.     

发酵丝孢酵母利用麻风果油饼固态发酵产油效果观察

目的利用发酵丝孢酵母榨过油的麻风果油饼进行固态发酵产油,提高产油量。方法从若尔盖草原取样的土壤中筛选出的产油性能较好的菌株发酵丝孢酵母,利用混合糖发酵产油脂,初步分析该酵母分别以葡萄糖、木糖和混合糖为碳源发酵生产油脂的特性。结果分别利用70 g/L葡萄糖和70 g/L木糖作为碳源在30℃下摇瓶发酵96 h,糖利用率均达90%以上,菌体生物量分别为14.1 g/L和13.1 g/L,油脂含量分别为55.7%和52.6%。相同条件下该菌株利用混合糖(葡萄糖46.6 g/L,木糖23.4 g/L)为碳源时总糖利用率、生物量和油脂含量分别为75.1%、15.0g/L和40.0%。结论该菌株利用混合糖发酵产油的最佳培养基组成:混合糖浓度79.8 g/L、酵母粉浓度8.9 g/L、FeSO4浓度8.0 mg/L、KH2PO4浓度7 g/L、Na2HPO4浓度2 g/L、MgSO4浓度1 g/L、NH4C l浓度0.5 g/L。经摇瓶培养,该菌株生物量达到了18.0 g/L、油脂量为10.9 g/L、油脂含量达到了60.6%;在7 L发酵罐扩大培养中,生物量达到了27 g/L、油脂量达到了15.8 g/L、油脂含量达到了58.8%。     

中式快速发酵香肠最佳工艺参数研究

根据美国肉类协会(AMI)为抑制金黄色葡萄球菌生长对发酵香肠生产时间和温度进行的限定,设计正交实验,对影响发酵香肠生产的三个主要因素(菌种出例、GDL添加量、葡萄糖添加量)进行讨论。并对产品进行感官评价,确定发酵香肠生产最佳配方为发酵剂(5:1),GDL(1．2％),GLC(0．6％)。按最佳配方生产的产品亚硝酸盐残留为7．13 mg／l,符合国家对肠制品亚硝酸盐残留的规定。     

工程菌表达融合型酯酶B1发酵条件的优化

目的 提高酯酶B1融合蛋白的表达量,研究pThioHisA-B1/DH5a工程菌株的最优发酵条件.方法 依次在不同的培养基(LB,SOB,YT,TB)、诱导时间(1-8 h)、诱导剂浓度(0.3-1 mmol/L)、诱导温度(25～37℃)等因素变化下,研究融合蛋白的表达量;目的 产物经SDS-PAGE电泳和薄层凝胶扫描,以获得最佳表达条件.结果 工程菌优化的发酵条件为,最适宜的培养基为TB,诱导剂IPTG的最佳浓度为0.4 mmol/L,最佳诱导时间为6 h,最佳诱导温度为28℃.工程菌在最佳条件下表达时,融合蛋白的表达量占菌体总蛋白的40.3%,其中66.2%为可溶性蛋白.结论 本实验筛选出了工程菌的最优化发酵条件,利用本实验的优化条件可获得高产量、可溶性的酯酶B1融合蛋白,为酯酶B1的进一步放大生产和实际应用奠定了基础.     

具有灭螺活性的金钱松内生真菌JJ18发酵条件优化

目的通过改进发酵工艺提高金钱松内牛真菌JJ18的杀螺活性。方法采用单因素和正交试验对发酵培养基及发酵条件进行优化。按照WHO的杀螺剂浸泡试验法，以杀螺率为主要衡量指标，同时考察发酵液的生物量，对金钱松内生真菌JJ18发酵条件进行优化。结果以马铃薯175g／L为氮源，初始pH值6．0，葡萄糖和蔗糖15g／L为碳源，磷酸二氢钾0．5mmol／L为代谢调节因子，接种量2％，250ml三角瓶装液量50m1，温度30℃，120r／min，发酵7d，杀螺活性最大提高16．7％。生物量与杀螺率存在一定的相关性。结论通过改变发酵工艺可以提高杀螺活性，金钱松内生真菌JJ18具有开发应用的潜力。     

大蒜油的提取工艺研究

目的:确立从大蒜中提取大蒜油的最佳工艺。方法:采用正交设计实验方法对影响出油率的主要因素发酵温度、发酵时间、加水量、提取时间进行优化设计。结果:影响出油量的主要因素是A(发酵温度),其次为D(提取时间),C(加水量),B(发酵时间)对出油量影响较小,提取条件以A3B2C1D3为最佳,即将大蒜于55℃发酵2 h,加2倍量水提取6 h。结论:采用此法提取大蒜油出油率高,方法简单可行。     

温度对芦笋秸秆水解发酵的影响

研究了温度条件(25、35、45、55℃)对芦笋秸秆水解发酵及腐殖化过程的影响。通过对芦笋秸秆水解产物以及水解后残余物进行分析,发现温度升高可显著加速纤维素的分解,经过16 d的水解发酵,55℃条件下可得到固体干重降解率59.2%、纤维素降解率32.1%。水解产物的腐殖化指数(HIX)和荧光指数(FI)表明,较高的温度亦可提升腐植酸的转化率,55℃试验组的黄腐酸产量与转化率分别为7 320 mg/L、15.4%。     

CPP-ACP对发酵乳杆菌生长、黏附影响的实验研究

[目的]研究酪蛋白磷酸肽钙磷复合体(Casein phosphopeptide-Amorphic Calcium Phosphate,CPP-ACP)对发酵乳杆菌生长、黏附的影响,进一步探讨CPP-ACP的防龋机制。[方法]将发酵乳杆菌接种到BHI培养基,实验组中加入不同浓度(0.5%～5.0%(W/V))的CPP-ACP溶液,厌氧培养48h后,采用噻唑蓝(MTT)比色分析法测定细菌浓度的吸光度A值(λ=550nm)。采用唾液包被的羟磷灰石(Saliva-coated hydroxyapatite,S-HA)形成实验性膜,用不同浓度(0.5～5.0%(W/V))CPP-ACP处理S-HA,定量观察发酵乳杆菌在S-HA上的黏附情况。[结果]随CPP-ACP浓度的升高,发酵乳杆菌甲臜产物的二甲亚砜溶液的吸光度值降低,即发酵乳杆菌的活菌数减少(P﹤0.01)。发酵乳杆菌对经各实验浓度的CPP-ACP处理后的S-HA黏附能力明显下降,黏附量(cpm)随CPP-ACP浓度的升高而降低,黏附抑制率达100%。[结论]CPP-ACP对发酵乳杆菌的生长以及在S-HA上的黏附具有抑制作用,随CPP-ACP浓度的升高抑制作用增强。     

淫羊藿苷酸法水解工艺的研究

目的与方法:利用化学方法制备淫羊藿苷元。通过单因素和正交试验得到淫羊藿糖苷酸法水解为淫羊藿苷元的最佳工艺条件。结果与结论:结果表明:影响淫羊藿糖苷酸水解的因素从大到小依次为酸浓度、水解温度、水解时间。最佳工艺条件为硫酸的浓度为5mol/L,水解温度为90℃,水解时间72h,酸法水解率为80%。     

商丘城市生活垃圾发酵处理效果观察

目的调查城市生活垃圾发酵处理效果。方法用微生物对100吨城市生活垃圾进行发酵处理,第6天垃圾的温度超过70°且在此温度保持7天,然后温度逐渐下降至15天。结果处理后在垃圾固有微生物中,细菌总数、真菌数、产气夹膜杆以及粪大肠菌群的量分别下降了95.51%、99.90%、87.60%和99.7%。对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、白色念球菌以及蛔虫卵的杀灭率分别为99.90%、100%、96.10%、99.89%以及99.33%。结论城市生活垃圾发酵处理能很好地使垃圾达到无害化标准。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.