Recreational exposure to low concentrations of microcystins during an algal bloom in a small lake

We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-μg/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses), but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 μg/L to 5 μg/L) in the water and (<0.1 ng/m³) in the aerosol samples. Blood levels of microcystins for all participants were below the limit of detection (0.147μg/L). Given this low exposure level, study participants reported no symptom increases following recreational exposure to microcystins. This is the first study to report that water-based recreational activities can expose people to very low concentrations of aerosol-borne microcystins; we recently conducted another field study to assess exposures to higher concentrations of these algal toxins.     

松香基水性聚氨酯丙烯酸酯复合乳液的研制

以富马海松酸水性聚氨酯(FWPU)和甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)等为主要原料,合成富马海松酸型水性聚氨酯-丙烯酸酯复合乳液(FWPUA)。探讨了引发剂的种类和用量及丙烯酸酯加入量等因素对反应的影响。对所得产品进行了红外光谱分析,并测试了漆膜的拉伸强度、镜面光泽、摆杆硬度和耐溶剂性。结果表明:用偶氮二异丁腈和过硫酸铵为复合引发剂,引发剂用量为0.8%,丙烯酸酯的加入量为30%时,复合乳液的拉伸强度、摆杆硬度、耐水性、耐碱性、耐醇性和镜面光泽均有不同程度的提高。     

超支化水性聚氨酯羟基组分的制备及成膜性能研究

以季戊四醇为核,丙烯酸甲酯和二乙醇胺的加成产物为单体合成了端羟基超支化聚（胺-酯）,将其接枝到端-NCO的聚氨酯预聚体上得到了超支化的水性聚氨酯羟基组分。探讨了温度和时间对羟基组分中-NC0含量的影响,采用化学滴定、红外光谱（FTIR）等方法对产物进行了表征和分析。结果表明：适宜的反应温度为75℃,反应时间为6h;以DesmodurDN作固化剂可以制得性能良好的漆膜。漆膜附着力可达到1级,耐冲击强度50cm,铅笔硬度3H,耐水性24h无变化。     

自催化型萜烯基环氧树脂多元醇水分散体的制备与表征

利用N-苄基乙醇胺(BEA)或二乙醇胺(DEA)改性萜烯-马来酐缩水甘油酯型环氧树脂(TME),制备了分子结构中含有叔胺基团的自催化型萜烯基环氧树脂多元醇(TBP或TDP)。通过分析合成反应的影响因素,确定了制备环氧树脂基多元醇TBP和TDP的最佳反应条件:反应温度80℃,反应时间1 h,溶剂乙醇用量为反应物总质量的10%。采用傅里叶红外(FT-IR)光谱、核磁共振(NMR)光谱及凝胶渗透色谱(GPC)表征了环氧树脂基多元醇及其水分散体(WTBP或WTDP)的化学结构和相对分子质量分布,以激光粒径仪考察了中和度对多元醇水分散体粒径分布的影响。当中和度为90%时,多元醇水分散体(WTBP和WTDP)粒径为多峰分布,分散体稳定性较差;当中和度为100%时,水分散体粒径为单峰分布,达到纳米级分散。     

相反转乳化法制备萜烯酯型环氧树脂乳液的研究

以自制的聚乙二醇改性萜烯酯型环氧树脂(TP)为乳化剂,采用相反转法乳化萜烯酯型环氧树脂制备了环氧树脂水乳液,分析了乳化过程中体系电导率变化与微观形态转变的关系,讨论了乳化剂质量分数、乳化温度、搅拌速度、乳液固含量等条件对乳液粒子体积平均粒径(D[4,3])及粒径分布一致性、黏度、离心稳定性、环氧值及环氧保留率等乳液性质的影响.实验结果表明,该环氧树脂乳液的最佳制备条件为:TP质量分数16.7%,乳化温度60℃,机械搅拌速度500-900 r/min,固含量约45%.在该条件下制备的乳液性质最好,乳液粒子体积平均粒径约200 nm,粒径分布100-440 nm,黏度850 mPa·s,环氧值0.11 mol/100 g.     

水源中隐孢子虫种类和基因型鉴定技术研究进展

目前,隐孢子虫有效种有20个。隐孢子虫的分子流行病学研究表明,隐孢子虫具有宿主特异性。目前,感染人的隐孢子虫种和基因型有C．horninis、C.parvum、C．meleagridis、C.felis、C.canis、C.nuris、C．suis genotype和C．cervine genotype等。水源性隐孢子虫暴发,具有重要的公共卫生意义。分子鉴定技术已广泛应用于检测水中隐孢子虫,水中检测到的隐孢子虫有9个。通过分析其分子组成特性表明,成年牛可能是水污染的主要根源,除了居民用水和农业污染外,鹿、麝鼠、田鼠、鸟和其它野生动物可能也与水污染有关。隐孢子虫分子基因型鉴定工具可能为水源保护性研究提供一个更有力的溯源追踪工具。     

Comparison of serological, culture, and bait methods for detection of Pythium and Phytophthora zoospores in water

Two immunodiagnostic detection assay procedures were compared with two conventional assays for their sensitivity in detecting propagules of Pythium ultimum var. sporangiiferum , Pythium Group F, Phytophthora cactorum and P. cryptogea in dilution series in sterile distilled water. The most sensitive assay for all four species was the zoospore trapping immunoassay (ZTI). Conventional membrane filtration-dilution plating gave similar results to ZTI with the two Phytophthora spp., but was less sensitive in Pythium detection. Immunodiagnostic dipstick assays and conventional bait tests showed similar sensitivities in the dilution series, and were generally about two orders of magnitude less sensitive than ZTI. The four techniques were also compared for their detection efficacy with water samples collected from horticultural nurseries and in in situ tests of infected root zones of Chamaecyparis , tomato and Chrysanthemum . In these comparisons, ZTI was again the most sensitive test for water samples, although membrane filtration-dilution plating proved to be a more consistent test. Dipstick and baiting assays were the best techniques for in situ testing, and dipsticks provided epidemiologically valuable, quantitative data on pathogen propagule numbers.     

MUF-PVAc共混树脂基膨胀型水性木材阻燃涂料的研究Fire retardant properties of intumescent waterborne fire-retardant coatings based on MUF-PVAc mixed resin for wood

以三聚氰胺改性脲醛树脂（MUF）与聚乙酸乙烯酯树脂（PVAc）共混物作为成膜树脂,以磷酸脒基脲（GUP）、聚磷酸铵（APP）、三聚氰胺（MEL）和季戊四醇（PER）的组合物为膨胀阻燃体系,制备适用于木材的膨胀型水性阻燃涂料。以锥形量热仪法、傅里叶变换红外光谱法和热重分析法为评价手段,对膨胀型水性木材阻燃涂料涂覆的胶合板A、仅涂覆成膜树脂的胶合板M和素胶合板S的阻燃性能进行了对比分析。结果表明：胶合板A的热释放速率、总热释放、烟释放速率均比胶合板M、胶合板S的显著降低,但其残余物质量最高,并显著延长了点燃时间。在传统的膨胀型阻燃体系中引入GUP后,与APP在不同温度区间起到催化成炭作用,有利于提高涂料的阻燃性能。胶合板A的涂层受热辐射后炭化彻底,表明GUP-APP-MEL-PER是MUF-PVAc共混树脂的有效膨胀型阻燃体系。     

丙烯酸异冰片酯改性水性聚氨酯的合成及其表征

通过乳液聚合法制备了丙烯酸异冰片酯(IBOA)改性水性聚氨酯(WPU)复合乳液,考察了引发剂用量、反应温度、IBOA/WPU质量比及保温时间对单体转化率、胶膜吸水率及拉伸强度的影响,同时采用正交试验对工艺条件进行了优化。研究结果表明,较适宜的反应条件为IBOA与WPU固体组分质量比为1∶3,引发剂过硫酸铵(APS)用量为IBOA单体添加量的0.5%,反应温度80℃,保温熟化3 h。利用傅立叶变换红外光谱、透射电子显微镜、热重分析等测试方法对复合材料的性能进行了表征,并探讨了性能与结构的关系,结果显示单体的平均转化率达97.35%,改性水性聚氨酯的吸水率达到5.94%,拉伸强度达到27.17 MPa。制备的乳液为核壳结构,乳液稳定性良好;胶膜发生的热降解分别由硬段降解和软段降解造成。     

阳离子型萜烯基环氧树脂多元醇的合成及其分散稳定性研究

利用二乙醇胺(DEA)、聚乙二醇200(PEG200)对氢化萜烯 - 马来酸酐缩水甘油酯型环氧树脂(HTME)改性,制备了阳离子型环氧树脂基多元醇水分散体.通过对合成反应影响因素分析,确定了制备环氧树脂基多元醇的最佳反应条件:DEA用量为12%(以HTME的质量计,下同),PEG200与HTME(与DEA氨基反应后的量)物质的量比为1: 1 ～ 1.2: 1;催化剂ZnCl_2用量为2%,在100℃下反应6 ～ 7h.通过化学分析和红外光谱分析方法表征了该多元醇的化学结构.随着PEG200用量的增加,所合成多元醇的羟值提高,软化点、玻璃化温度(T_g)及分散体黏度降低.纳米粒度及电位分析表明,在酸性条件下,DEA用量为12%时所合成的环氧树脂基多元醇具有良好的水分散稳定性,水分散体的Z均粒径小于100nm.多元醇水分散体在高固含量时黏度较大,添加适量极性惰性稀释剂丙二醇甲醚醋酸酯可有效降低分散体黏度.