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1.
[目的]研究了稻田水环境中吡虫啉的残留动态.[方法]田水样品采用二氯甲烷萃取,HPLC-UV测定不同田水样品中的吡虫啉残留量.[结果]田水中吡虫啉的平均添加回收率为89.69%~92.06%、标准偏差为3.01%~3.73%、变异系数为3.79%~4.46%,吡虫啉的最小检出量为1.0×10<'-9>g,在田水中最低检测浓度为0.005 mg/L.在安徽的试验结果表明,吡虫啉在碍水中降解半衰期为4.4 d.[结论]10%吡虫啉乳油在稻田使用后,在田水中降解较快.  相似文献   

2.
[目的]建立SPE-柱前衍生-HPLC法测定甘蓝和土壤中阿维菌素残留量的分析方法,并研究阿维菌素在甘蓝和土壤中的残留动态和最终残留量.[方法]样品用乙腈提取,C18 固相萃取(SPE)小柱净化,经N-甲基咪唑(NMIM)和三氟乙酸酐(TFAA)衍生化,用乙腈定容,最后用液相色谱-荧光检测器(激发波长为365 nm,发射波长为475 nm)进行测定.[结果]阿维菌素在甘蓝中半衰期为1.5~5.4 d,在土壤中降解的半衰期为6.7~8.8 d.、建议45.5%阿维菌素·丁醚脲悬浮剂防治十字花科蔬菜中的小菜蛾,在推荐剂量下最多施药2次,安全间隔期为4 d.[结论]建立的分析方法操作简单,方法的精密度、准确度和灵敏度都符合农药残留标准要求,适用于基质复杂的甘蓝和土壤中阿维菌素的残留测定.  相似文献   

3.
[目的]建立一种土壤样品的测定方法.[方法]将电镀厂周围土壤样品,磨碎,过130目筛,取1.000 g土壤样品于聚四氟乙烯坩埚中,加入10 ml H<,2>O<,2>放置过夜,在微波炉中消解至近干;加15 ml浓HCl、5 ml浓HNO<,3>消解至近干,再加5 ml HF,继续消解至粘稠状,用去离子水低温溶解残渣,转入25 ml容量瓶中,加5%HNO<,3>定容,用ICP-AES法测定土壤中的Zn、Ni、Cr、Cu.[结果]在选定的测定条件下,检出限分别为0.005 2、0.013、0.006 9、0.009 6 mg/L;精密度的相对标准偏差分别为2.4%、2.9%、2.1%、3.4%;回收率在98.3%~103.7%.[结论]该测定方法灵敏、精密、准确度高;电镀厂周围土壤已经受到了影响,应严格加强管理.  相似文献   

4.
[目的]建立气相色谱测定大豆和植株中戊唑醇残留的分析方法.[方法]样品经丙酮提取、液-液分配、弗罗里硅土层析柱净化后,采用气相色谱氮磷检测器进行测定.[结果]在添加量为0.02~1.00 mg/kg范围内,戊唑醇在大豆和植株中的平均回收率分别为90.7%~105.3%和93.2%~100.6%,相对标准偏差分别为2.1%~8.9%和1.7%~4.6%;方法的最低检出量为1×10<'-10>g,最低检测浓度为0.01 mg/kg.[结论]该方法简单、快速,结果准确,灵敏度、精密度和检测限均符合农药残留分析的要求.  相似文献   

5.
[目的]了解敌敌畏在萝卜上的残留动态,为其在萝卜上的安全使用提供理论依据.[方法]在萝卜上喷施3种不同浓度的敌敌畏,测定不同时期采收的萝卜根和叶中敌敌畏的残留量.[结果]敌敌畏在萝卜根中降解速度明显大于在萝卜叶中.敌敌畏在萝卜叶上半衰期为4~6 d,在萝卜根中的半衰期在2~4 d.按推荐药量喷施时,施药15 d后萝卜根中敌敌畏的最终残留量才会在FAO/WHO规定的允许范围之内.[结论]敌敌畏在萝卜上的安全施用浓度为1:2 000~1:1 000倍,安全采收间隔期为15~20 d.  相似文献   

6.
[目的]建立狄氏剂在小麦中的残留量分析方法,并利用该方法对我国7个省份所抽小麦样品狄氏剂残留量进行检测.[方法]样品采用石油醚提取,弗罗里硅土层析柱净化,气相色谱一电子捕获检测器测定.[结果]添加浓度在0.020~0.002mg/kg范围内,回收率为89.90%~94.10%,变异系数为2.51%~3.79%.狄氏剂的最小检出量为0.002 ng,方法最低检出浓度为0.001mg/kg.7个省份所采小麦样品中狄氏剂残留量均低于GB 2763-2005规定的狄氏剂在粮谷中残留限量标准(0.020 mg/kg),也低于方法的最低检出浓度(0.001mg/kg).[结论]该方法的准确度、精确度、灵敏度都符合农药残留分析要求,目前我国小麦中狄氏剂残留水平较低.  相似文献   

7.
[目的]利用微波消解石墨炉原子吸收法测定茶叶中镍含量.[方法]分别从消解液和样品消解量方面进行消解条件的优化,以建立最适合的消解方法.[结果]茶叶样品以5 ml HNO3-2 ml H2O2 混合体系为消解液,坡度升温方式微波高压密闭消解结合石墨炉原子吸收光谱法测定,样品检出限为0.15 μg/g,回收率为97.8%,RSD为1.9%.[结论]该方法简单快速,效率高,劳动强度低,是进行茶叶中镍元素测定的高效方法.  相似文献   

8.
[目的]建立一种简便、快速测定豆腐花中铅含量的方法.[方法]采用微波消解法处理豆腐花样品,石墨炉原子吸收光谱法测定豆腐花中铅含量,并通过正交试验设计方法对微波消解参数进行了优化.[结果]测定铅的标准曲线相关系数为0.9994,相时标准偏差在0.32%~2.17%,加标回收率在95%~104%,检出限为1.454μg/L.[结论]用微波消解作为预处理手段,以石墨炉原子吸收分光光度法测豆腐花中铅的含量是一种可行的方法,具有精密度高、准确度好等优点.  相似文献   

9.
[目的]对以花生样品为代表的油脂类农产品的测定方法进行改进.[结果]采用高压罐消解-氢化物-原子荧光光谱法对花生中硒进行消解、测定.[方法]建立花生高压罐消解的最佳分析条件,确定原子荧光光谱仪的参数设置和最佳氢化反应条件.方法的检出限为0.2 μg/L,线性范围为0~100 ng/ml,相关系数γ为0.9999,回收率为96.6%~100.0%.[结论]该方法可用于油脂类含量较高的花生等农产品中硒含量的测定.  相似文献   

10.
[目的]为检测海带中铅寻找更适合的方法.[方法]采用微波消解法进行样品前处理,用氢化物发生原子荧光光谱法检测海带中的铅.[结果]铅的最低检出限为0.085 2 μg/L,方法的相对标准偏差小于10%,回收率为89.1%~107.2%.[结论]该法简单,快速,灵敏度高,对环境污染轻,用于海带中铅的检测获得令人满意的结果.  相似文献   

11.
12.
Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the 1st study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the 2nd study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles. In both studies, the participants' highest levels of subjective affective and cardiovascular (CV) arousal occurred when they spoke about the emotional events in a mood-congruent voice style: fast and loud in the case of fear and anxiety, and slow and soft in the case of sadness or depression. Mood-incongruent voice styles canceled the heightened levels of CV arousal normally associated with these negative emotions. The voice-style manipulation had no significant effect on the participants' levels of CV arousal during the neutral discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
Despite the use of multimodal therapy, higher-grade glioma is still uniformly fatal in the adult population. There is a considerable difference between the length of survival in each given patient, even within the same tumor type and malignancy grade group, suggesting that there are factors that might differentially influence outcome. To identify such factors, 107 patients with anaplastic or malignant glioma were retrospectively investigated. Clinical parameters and paraclinical data on the p53, mdm2, and EGFR genes at the DNA or protein level were evaluated by univariate analysis and Cox proportional hazards regression modeling. Kaplan-Meier survival estimation demonstrated that immunohistochemical positivity for mdm2 protein in patients with anaplastic astrocytoma or with glioblastoma multiforme was associated with a shorter survival time (p = 0.02). P53 gene mutations and immunopositivity for the epidermal growth factor receptor (EGFR) protein were not significantly related to poor prognosis. The Cox proportional hazards model revealed immunohistochemical positivity for p53, mdm2, or for both of them, the presence of postoperative irradiation, and the extent of surgical resection of tumor to be variables significantly associated with prolonged survival. EGFR overexpression, age over 60 years, and Karnofsky performance score below 40 points did not significantly shorten survival time. In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as a statistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma. Association analysis of variables revealed a possible correlation between mdm2 and p53, which is also consistent with the biological interaction mode of both proteins in vivo.  相似文献   

14.
BACKGROUND: As aging research increasingly reflects an effort to dissociate true time-driven changes from those that can be improved, sexuality in later life remains largely unexplored. Several problems are evident. There is a lack of normative data, a lack of a conceptual framework relating to the biology, psychology, and sociology of sex, and an attitudinal resistance that obscures the entire topic. METHODS: We conducted a three-part instructional series on major topics involved with sexuality and aging. We surveyed our group of attendees (n 158, average age 68 for males, 65 for females) before and after the series. RESULTS: A remarkably robust sex life was evidenced by both the men and the women, even until advanced old age. Yet, a substantially decreased involvement was reported from 10 years earlier. Despite current activities, people of both sexes wished they were participating even more than they currently were. Impotency was identified as the major negative feature for the men; relationship problems were for the women. A questionnaire 6 months after the series reported improved sexual attitudes, but no change in sexual activities from the earlier survey. CONCLUSION: Sexuality is a major quality-of-life issue which persists into old age. Our study showed that the usual sexual practices reported by our group were not considered by them to be ideal. The intervention of this instructional series provided improved sexual attitudes but not performance. Additional studies are encouraged.  相似文献   

15.
OBJECTIVE: To test the validity of Benjamin Franklin's maxim "early to bed and early to rise makes a man healthy, wealthy, and wise." DESIGN: Cross sectional analysis of sleeping patterns in a nationally representative group of elderly people, and longitudinal investigation of mortality. SETTING: Eight areas in Britain (five in England, two in Scotland, and one in Wales). SUBJECTS: 1229 men and women aged 65 and over who in 1973-4 had taken part in a survey funded by the Department of Health and Social Security and for whom data on sleeping patterns, health, socioeconomic circumstances, and cognitive function had been recorded. MAIN OUTCOME MEASURES: Self reported income, access to a car, standard of accommodation, performance on a test of cognitive function, state of health and mortality during 23 years of follow up. RESULTS: 356 people (29%) were defined as larks (to bed before 11 pm and up before 8 am) and 318 (26%) were defined as owls (to bed at or after 11 pm and up at or after 8 am). There was no indication that larks were richer than those with other sleeping patterns. On the contrary, owls had the largest mean income and were more likely to have access to a car. There was also no evidence that larks were superior to those with other sleeping patterns with regard to their cognitive performance or their state of health. Both larks and owls had a slightly reduced risk of death compared with the rest of the study sample, but this was accounted for by the fact that they spent less time in bed at night. In the study sample as a whole, longer periods of time in bed were associated with increased mortality. After adjustment for age, sex, the presence of illness, and other risk factors, people who spent 12 or more hours in bed had a relative risk of death of 1.7 (1.2 to 2.5) compared with those who were in bed for 9 hours. The lowest risk occurred in people who spent 8 hours in bed (adjusted relative risk 0.8; 0.7 to 1.0). CONCLUSION: These findings do not support Franklin's claim. A "late to bed and late to rise" lifestyle does not seem to lead to socioeconomic, cognitive, or health disadvantage, but a longer time spent in bed may be associated with increased mortality.  相似文献   

16.
Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.  相似文献   

17.
The constructs of intelligence and ego-resiliency are discussed. The personality implications of "pure intelligence" and "pure ego-resilience" were identified. Intelligence (IQ) was indexed by the Wechsler Adult Intelligence Scale-Revised (WAIS—R) and ego-resiliency by an inventory scale. Residual scores measuring "pure intelligence" and "pure ego-resilience" were correlated with the items of the observer based California Q-sort, used to describe participants. Persons relatively high on ego-resilience tend to be more competent and comfortable in the "fuzzier" interpersonal world; persons defined primarily by raw IQ tend to be effective in the "clearer" world of structured work but tend also to be uneasy with affect and less able to realize satisfying human connections. Gender differences exist in the relations of ego-resilience and intelligence and in their adaptive relevance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

18.
Investigated the effects of modeling and corrective feedback on the conservation of equalities and inequalities, with items spanning 3 stimulus dimensions (length, number, and 2-dimensional space). Ss were 48 kindergartners (24 boys, 24 girls). Brief observation of a model, briefer correction training (joining positive feedback with verbal rule provision), and the combination of observation and correction were all successful in producing learning and, without further training, transfer and retention of conservation. Unlike the controls (who also never correctly answered any equality items), the trained experimental Ss gave evidence of spontaneously generalizing their new learning to a task that required nonverbal behavior to manifest conservation. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
Examines strategies that are used to reason about food and contamination. In Exp 1, Ss refrained from choosing a substance that had been given a "poison" label when the intent of the labeler was ambiguous or malicious but preferred this substance when a rationale was provided that dispelled the implication that there once might have been contaminants present. Exp 2 was designed to compare the effects of safety on conditional reasoning in food and food-irrelevant contexts. When the safety issue was relevant to food in the form of contamination, Ss were most likely to use formal logic in reasoning. A similar pattern of responses was found in Exp 3 on tasks for which Ss' ratings of their experience of contexts were matched for plausibility, experience, and danger. Results are discussed in terms of an adaptive constraint that facilitates rationality in reasoning within the food domain (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

20.
根据深云立交桥梁的检测结果,对该桥目前的整体状况、工作状态,及其使用情况做出综合评价,对桥的病害原因进行了分析,并提出合理的加固方案。  相似文献   

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