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91.
The main focus of this study was to evaluate long term effects of cadmium on forearm bone mineral density after stopping ingestion of cadmium-polluted rice for 10 years in a Chinese population. A total of 532 persons (338 women and 194 men), living in control, moderately and heavily polluted areas, were included in this study. The residents living in the polluted area ceased ingesting cadmium-polluted rice in 1996. All participants were require to answer a questionnaire and the bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at the proximal radius and ulna. Samples of urine and blood were collected for determination of cadmium in urine (UCd) and blood (BCd).The BMD of subjects living in the heavily polluted area was significantly lower than that of those living in control area in both men and women (p < 0.01). For the people living in the moderately polluted area, only the women's BMD was greatly lower compared to that in the control area (p < 0.05). The BMD declined with the increasing BCd and UCd in both sexes, especially in the highest level (BCd > 5 µg/L, UCd > 10 µg/g crea) groups (p < 0.01). It was found that there were significant differences in the prevalence of osteoporosis among the different areas (χ2 = 13.046, p = 0.0003) and different UCd groups (χ2 = 4.511, p = 0.0337) in women, but not in men (χ2 = 0.962, p = 0.3268; χ2 = 1.906, p = 0.1675). But a significant difference exists in the prevalence of osteoporosis among different BCd groups in both genders (χ2 = 9.304, p = 0.00229, in women; χ2 = 4603, p = 0.0319, in men). This study suggested that cadmium could play a long-term role on bone and more attention should be paid to cadmium effects on bone metabolism after reduction of exposure. 相似文献
92.
浙江省沿海地区农村房屋抗风情况调研 总被引:4,自引:0,他引:4
对浙江省沿海地区的农村房屋抗风情况进行了调研,总结了被破坏房屋的主要结构特点。在对现有房屋的统计中发现相对不富裕地区高达60%以上的房屋属于抗风能力差和较差的,而一些比较富裕且受过台风袭击有过惨痛教训地区的房屋抗风能力差和较差的仅在20%以下。进一步研究发现抗风能力较好的房屋大都是建造年代不久,多为混凝土现浇板屋盖,上部多为框架或砖混结构,而抗风能力较差和差的大都为建造年代已久,多为小青瓦屋面,上部结构多为砖木结构或构造措施较差的砖混结构。同时对当地村民传统的"砖头压瓦"防护措施进行理论验算,得出当风速超过台风界限风速时,屋面上的砖头将会飞起,该措施应该避免。 相似文献
93.
Zhang F Gu W Xu P Tang S Xie K Huang X Huang Q 《Waste management (New York, N.Y.)》2011,31(6):1333-1338
Composting is the biological degradation and transformation of organic materials under controlled conditions to promote aerobic decomposition. To find effective ways to accelerate composting and improve compost quality, numerous methods including additive addition, inoculation of microorganisms, and the use of biosurfactants have been explored. Studies have shown that biosurfactant addition provides more favorable conditions for microorganism growth, thereby accelerating the composting process. However, biosurfactants have limited applications because they are expensive and their use in composting and microbial fertilizers is prohibited. Meanwhile, alkyl polyglycoside (APG) is considered a “green” surfactant. This study aims to determine whether APG addition into a compost reaction vessel during 28-day composting can enhance the organic matter degradation and composting process of dairy manure. Samples were periodically taken from different reactor depths at 0, 3, 5, 7, 14, 21, and 28 days. pH levels, electrical conductivity (EC), ammonium and nitrate nitrogen, seed germination indices, and microbial population were determined. Organic matter and total nitrogen were also measured.Compared with the untreated control, the sample with APG exhibited slightly increased microbial populations, such as bacteria, fungi, and actinomycetes. APG addition increased temperatures without substantially affecting compost pH and EC throughout the process. After 28 days, APG addition increased nitrate nitrogen concentrations, promoted matter degradation, and increased seed germination indices. The results of this study suggest that the addition of APG provides more favorable conditions for microorganism growth, slightly enhancing organic matter decomposition and accelerating the composting process, improving the compost quality to a certain extent. 相似文献
94.
95.
Heinz G. Stefan .Ruochuan Gu 《Journal of the American Water Resources Association》1991,27(6):967-978
ABSTRACT: Forced artificial mixing of temperature-stratified ponds, or small lakes or reservoirs, by liquid jets can enhance water quality and can also be energy efficient. Based on previous studies of jet mixing mechanics of stratified water bodies, a conceptual design approach is presented. The main “operational” and “system” design parameters are considered in the proposed method. Using minimization of a total cost estimate as a criterion, an iterative method for the selection of the number and size of the jets is developed and illustrated. 相似文献
96.
97.
Treatment of perchlorate‐contaminated groundwater using highly selective, regenerable ion‐exchange technology has been recently demonstrated at Edwards Air Force Base, California. At an influent concentration of about 450 μg/l ClO4?, the bifunctional anion‐exchange resin bed treated approximately 40,000 empty bed volumes of groundwater before a significant breakthrough of ClO4? occurred. The presence of relatively high concentrations of chloride and sulfate in site groundwater did not appear to affect the ability of the bifunctional resin to remove ClO4?. The spent resin bed was successfully regenerated using the FeCl3?HCl regeneration technique recently developed at the Oak Ridge National Laboratory, and nearly 100 percent of sorbed ClO4? was displaced or recovered after elution with as little as about two bed volumes of the regenerant solution. In addition, a new methodology was developed to completely destroy ClO4? in the FeCl3?HCl solution so that the disposal of perchlorate‐containing hazardous wastes could be eliminated. It is therefore anticipated that these treatment and regeneration technologies may offer an efficient and cost‐effective means to remove ClO4? from contaminated groundwater with significantly reduced generation of waste requiring disposal. © 2002 Wiley Periodicals, Inc. 相似文献
98.
99.
城市控制爆破工程的爆破事故和爆破公害研究 总被引:4,自引:5,他引:4
爆破事故和爆破公害是关于爆破工程中的安全问题 ,笔者对爆破事故中的早爆、拒爆和爆破公害中的爆破振动、爆破空气冲击波、爆破飞石进行了详细论述 ,分析了爆破事故及公害产生的原因 ,从而给出了相应的防止措施 ;进而依法采取了爆破安全管理可行办法 相似文献
100.
本文使用我们合成的水溶性T(4—TAP)P作为显色剂发展了痕量铜的直接光度测定法。详细考察了测定铜的最佳条件和共存元素的影响。在盐酸羟胺存在下,pH4.5和HAc—NaAc溶液中形成一个1:1的Cu(I)—T(4—TAP)P络合物,λ_(max)=411nm,表观摩尔吸光系数为1.7×10~5L.mol~(-1)cm~(-1),s为0.00033μg·cm~(-2),铜浓度在0—5μg/25ml范围内服从比耳定律,该方法灵敏度高。选择性好,用于人发中痕量铜的测定结果满意。相对标准偏差为4.6%,回收率在93—103%之间。与AAS法和双乙醛草酰二胺分光光度法(BAO法)的结果比较,证明了方法的准确度,相对误差小于8%。 相似文献