超声辅助-王水提取法在测定土壤中重金属元素的应用

建立了超声辅助王水消解土壤样品的前处理方法,并结合电感耦合等离子体原子发射光谱法(ICP-AES)和电感耦合等离子体质谱法(ICP-MS)对土壤样品中铜、锌、镍、铁、锰、铅、砷、汞、铬、镉等10种元素进行测定。通过试验确定王水用量为5mL、超声水浴温度为80℃、超声提取时间为45min的超声提取条件。在优化的仪器条件下,按照实验方法测得的土壤样品中10种元素的校准曲线线性相关系数为0.9996~0.9999;各元素的检出限为0.0021~0.23mg/kg,各元素的测定下限为0.0070~0.78mg/kg。按照实验方法(超声王水提取-ICP-AES/ICP-MS)测定土壤样品中铜、锌、镍、铁、锰、铅、砷、汞、铬、镉,测定结果的相对标准偏差(RSD,n=6)为0.39%~7.8%;除铁、锰的提取值较小外,其他元素的测定结果与采用国标方法(GB 15618—1995、GB/T 22105.1—2008)得到的测定值基本一致;按照实验方法测定土壤标准物质GBW07404、GBW07406、GBW07407、GBW07427中铜、锌、镍、锰、铅、砷、汞、铬、镉,除了锰由于其在原土中主要以氧化物结合态存在,测定结果偏低以外,其他元素测定值与认定值相吻合。     

微波消解-氢化物发生原子荧光光谱法测定进口铜锍中砷和汞

建立了测定进口铜锍样品中砷、汞含量的氢化物发生原子荧光光谱法。在铜锍试样中加入王水和氢氟酸,经微波消解后稀释,消解液中加入硫脲-抗坏血酸预还原,加硼氢化钾使砷和汞生成硼氢化物,用原子荧光光谱法测定砷和汞含量。铜、铁、硫等对待测元素基体效应不显著。在选定条件下,砷和汞的检出限分别为0.003 9 μg/L和0.060 8 μg/L,样品的加标回收率在95 %～123 %之间,砷和汞的相对标准偏差分别为0.56%和2.0%(n=6),方法可用于大批铜锍样品中砷和汞的测定。     

电感耦合等离子体原子发射光谱法测定铜阳极泥中8种元素

以盐酸和硝酸溶解样品,采用电感耦合等离子体原子发射光谱法（ICP-AES）测定了铜阳极泥中铜、铅、硒、锑、铋、砷、铁、镍8种元素的含量。对取样量、试样的溶解、测定介质、分析谱线选择等测定条件进行探讨。在优选的条件下进行测定,基体和共存元素对被测元素没有干扰,不需要进行预分离。各元素校准曲线的线性范围：Cu为0～50 μg/mL,Pb、Se为0～20 μg/mL, Sb、Bi、As、Fe、Ni为0～10 μg/mL。校准曲线相关系数在0.999 1～0.999 9之间。该法已用于生产和经营中铜阳极泥样品的分析,样品的测定结果与化学法吻合,加标回收率为97.1%~106.8%,相对标准偏差在0.37%~2.7%之间。     

电感耦合等离子体原子发射光谱法测定铁矿石中16种元素

准确、快速地测定铁矿中各种杂质元素含量,对铁矿石质量判定具有重要意义。试验采用“酸溶-碱熔回渣”的方法消解样品,先用硝酸、盐酸溶解样品,再过滤,滤渣及滤纸灰化后再用碳酸钠-硼酸混合熔剂熔融,溶液中的总固体溶解量(TDS)为2.5mg/mL。采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌等16种元素。各待测元素校准曲线的线性相关系数均大于0.999;方法检出限为0.00018%~0.034%。实验方法用于2个铁矿石实际样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌的测定,结果的相对标准偏差(RSD,n=8)为0.40%~9.8%;按照实验方法测定4个铁矿石标准样品,测定值与认定值相吻合;测定4个铁矿石生产样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌,测定值与GB/T 6730系列标准方法测定值相吻合。     

电感耦合等离子体原子发射光谱法测定铁矿石中16种元素

准确、快速地测定铁矿中各种杂质元素含量,对铁矿石质量判定具有重要意义。试验采用“酸溶-碱熔回渣”的方法消解样品,先用硝酸、盐酸溶解样品,再过滤,滤渣及滤纸灰化后再用碳酸钠-硼酸混合熔剂熔融,溶液中的总固体溶解量(TDS)为2.5mg/mL。采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌等16种元素。各待测元素校准曲线的线性相关系数均大于0.999;方法检出限为0.00018%~0.034%。实验方法用于2个铁矿石实际样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌的测定,结果的相对标准偏差(RSD,n=8)为0.40%~9.8%;按照实验方法测定4个铁矿石标准样品,测定值与认定值相吻合;测定4个铁矿石生产样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌,测定值与GB/T 6730系列标准方法测定值相吻合。     

电感耦合等离子体原子发射光谱法测定活性炭中铁锌钙镁铅

活性炭样品经550 ℃高温焙烧后,以硝酸、氢氟酸和盐酸的混酸作为消解试剂,用微波消解法消解,电感耦合等离子体原子发射光谱法(ICP-AES)测定消解液中铁、锌、钙、镁和铅金属元素含量。试验结果表明:样品经高温焙烧后基体元素碳已除去,对测定没有干扰,因此可以直接用待测元素的标准溶液绘制校准曲线,不需要进行基体匹配。共存元素由于含量很低,在所选定的分析线下测定也没有干扰。方法的检出限如下:铁为0.02 μg/mL,锌为0.01 μg/mL、钙为0.01 μg/mL、镁为0.02 μg/mL,铅为0.05 μg/mL。样品测定结果的相对标准偏差(RSD)在1.7%～4.1%之间(n=9),回收率在94%~96%之间。     

基体分离-电感耦合等离子体原子发射光谱法测定高纯钼中9种元素

利用电感耦合等离子体原子发射光谱法(ICP-AES)测定高纯钼样品中杂质元素含量时,由于钼元素具有丰富的谱线,因此钼基体对待测元素干扰较大。为了消除钼基体对待测元素的干扰,实验使用过氧化氢溶解样品,过量硝酸沉淀分离钼基体作为样品前处理步骤,建立了基体分离-电感耦合等离子体原子发射光谱法测定高纯钼中钙、铬、铜、钴、镁、镍、锌、镉和锰的方法。使用4mL过氧化氢溶解样品,10mL硝酸沉淀钼基体,钼的沉淀效率大于99%,沉淀后,各待测元素背景等效浓度均有下降,且回收率都高于85%,随沉淀损失较少。使用高纯钼基体沉淀分离的方法配制校准曲线,各待测元素校准曲线线性相关系数均大于0.999 7;方法中各元素的定量限为0.20～2.03μg/g。实验方法用于测定高纯钼样品中钙、铬、铜、钴、镁、镍、锌、镉和锰,结果的相对标准偏差(RSD,n=5)为2.0%～4.8%,测定结果与电感耦合等离子体质谱法(ICP-MS)结果一致。     

电感耦合等离子体原子发射光谱法测定含铬镍生铁中镍铬锰磷钼铜钴

采用王水并滴加氢氟酸溶解含铬镍生铁样品,高氯酸冒烟,采用标准样品/控制样品制作校准曲线,测定过程采用内标法,实现了使用电感耦合等离子体原子发射光谱法(ICP-AES)测定含铬镍生铁中高镍、高铬以及锰、磷、钼、铜和钴等元素的测定。在仪器工作条件下,各元素校准曲线线性相关系数均大于0.999,其中镍元素线性相关系数达到0.999 9。方法中各元素的检出限为0.002 0～0.020 μg/mL。采用实验方法对含铬镍生铁实际样品中的镍、铬、锰、磷、钼、铜和钴含量进行测定,结果与国家标准化学分析方法基本一致,相对标准偏差(RSD,n=11)在0.53%～5.0%之间。     

微波消解-电感耦合等离子体原子发射光谱法测定含碳化铬锌物料中铅铜铁镉铬砷

含碳化铬锌物料中含有铬的碳化物,此类碳化物熔点高、化学稳定性好,普通的酸不能完全溶解,需要在强混合酸和高温条件下才能分解。实验选择硝酸-盐酸-氢氟酸并采用微波消解法溶解样品,既能将试样中难溶的碳化铬完全溶解,又有效避免了高温溶样对易挥发元素砷的损失,并使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铅、铜、铁、镉、铬、砷等元素含量。各元素测定范围为:0.10%≤w(Pb,Cu)≤5.00%;0.10%≤w(Fe)≤10.00%;0.010%≤w(Cd,Cr) ≤3.00%;0.08%≤w(As)≤3.00%。各元素在线性范围内校准曲线的线性相关系数均大于0.999,检出限为0.001~0.018μg/mL。实验方法用于测定5个典型含碳化铬锌物料原料样品铅、铜、铁、镉、铬、砷,结果的相对标准偏差(RSD,n=11)为0.75%~2.0%;按照实验方法测定3个含碳化铬锌物料样品中铅、铜、铁、镉、铬、砷,并采用其他方法(其中铅、铜、铁、镉按照GB 6730.30—2016《铁矿石化学分析方法 二苯基碳酰二肼光度法测定铬量》方法进行碱熔后,采用火焰原子吸收光谱法进行测定;铬按照GB 6730.30—2016《铁矿石化学分析方法 二苯基碳酰二肼光度法测定铬量》测定;砷按照GB/T 8151.7—2012《锌精矿化学分析方法 第7部分:砷量的测定 氢化物发生-原子荧光光谱法》测定)进行比对,结果相吻合。     

火焰原子吸收光谱法测定航空煤油中铅锰镁锌铜

油类样品易燃易爆,在对其中较低含量金属元素进行分析时极易引起被测元素损失且一般进样系统无法对其直接测定,因此测定时样品的前处理过程非常重要。实验取100 mL航空煤油样品于500 mL分液漏斗中,加入2.0 mL碘-二甲苯溶液和15 mL硝酸(1+9)重复萃取2次,将两次萃取液合并后再用10 mL水萃取一次,萃取液浓缩后采用火焰原子吸收光谱法(FAAS)进行测定,建立了测定航空煤油中铅、锰、镁、锌和铜5种元素含量的方法。结果表明:铅、锰、镁、锌和铜5种金属元素校准曲线的相关系数均大于0.999 0,方法检出限为0.009～0.256 μg/mL。采用实验方法对航空煤油样品进行测定,测定结果与电感耦合等离子体原子发射光谱法(ICP-AES)基本一致,相对标准偏差(RSD,n＝9)为0.86%～5.4%。将实验方法应用于4个不同产地的航空煤油样品中铅、锰、镁、锌和铜的测定,各个元素的加标回收率均在96%～103%之间。     

Psychopathy, schizophrenia, alcohol abuse, and violent recidivism

We have previously shown that CD44 partly mediates ovarian cancer cell attachment to peritoneal mesothelium through recognition of mesothelial-associated hyaluronate. CD44 is a major receptor for hyaluronate and exists as a standard 90-180-kDa form (CD44H), as well as several higher molecular mass variant forms produced by alternative splicing. To determine whether functional differences exist between CD44H and its variants we have investigated the relationship between CD44 isoform expression and mesothelial adhesion in 12 ovarian cancer cell lines. Eight lines were CD44 positive (range, 83-94%) and demonstrated significant binding to mesothelium and hyaluronate, whereas two lines showed reduced CD44 levels (3-13%) and demonstrated decreased binding. Interestingly, two other lines (OVC-3 and SW626) expressed CD44 in the majority of cells (>93%) and yet bound weakly to mesothelium. Mean linear fluorescence intensity of CD44 expressed by OVC-3 and SW626 cells was approximately one-half that of strongly binding cell lines, suggesting that the ability to adhere may be partly related to CD44 surface density. However, immunoprecipitation and immunoblot analyses revealed that standard CD44H represented only 23-31% of total CD44 in weakly binding cells, with the majority of species being comprised of CD44 variants. Indirect immunofluorescence of OVC-3 and SW626 cells confirmed the presence of CD44 variants containing exons v3, v6, and v9. In contrast, CD44H represented the majority (75-86%) of total CD44 expressed by strongly binding cell lines such as CAOV-3 and UPN36T. Transfection of CD44H cDNA into weakly binding OVC-3 cells restored significant mesothelial binding which was partly blocked by anti-CD44 antibody. These data suggest that the expression of CD44 is necessary but not sufficient for mediating attachment of ovarian cancer cells to mesothelium. Although CD44 variants may constitute the major CD44 species in certain ovarian cancer cell lines, it appears that these CD44 species are not always capable of mediating significant binding to mesothelium or hyaluronate. Rather, an adequate level of CD44H is the critical determinant of binding in this system. The role of CD44 variants in the process of ovarian cancer metastasis will require further investigation.     

Heterosis for viability, fecundity, and male fertility in Drosophila melanogaster: comparison of mutational and standing variation

If genetic variation for fitness traits in natural populations ("standing" variation) is maintained by recurrent mutation, then quantitative-genetic properties of standing variation should resemble those of newly arisen mutations. One well-known property of standing variation for fitness traits is inbreeding depression, with its converse of heterosis or hybrid vigor. We measured heterosis for three fitness traits, pre-adult viability, female fecundity, and male fertility, among a set of inbred Drosophilia melanogaster lines recently derived from the wild, and also among a set of lines that had been allowed to accumulate spontaneous mutations for over 200 generations. The inbred lines but not the mutation-accumulation (MA) lines showed heterosis for pre-adult viability. Both sets of lines showed heterosis for female fecundity, but heterosis for male fertility was weak or absent. Crosses among a subset of the MA lines showed that they were strongly differentiated for male fertility, with the differences inherited in autosomal fashion; the absence of heterosis for male fertility among the MA lines was therefore not caused by an absence of mutations affecting this trait. Crosses among the inbred lines also gave some, albeit equivocal, evidence for male fertility variation. The contrast between the results for female fecundity and those for male fertility suggests that mutations affecting different fitness traits may differ in their average dominance properties, and that such differences may be reflected in properties of standing variation. The strong differentiation among the MA lines in male fertility further suggests that mutations affecting this trait occur at a high rate.     

Effect of tinidazole, metronidazole and nitrofurazone on nucleic acid synthesis in Clostridium bifermentans

Coplanar lines of different orientations rotating in depth and viewed in parallel projection may appear to rotate in different directions and reverse independently of each other, or they may appear coplanar and all reverse together. The frequency of the latter "grouped" appearance for lines with an orientation range of 30 degrees was a function of the number of lines in a given space. Grouping was greater for lines converging to an implicit vanishing point and for lines with collinear edges regardless of their orientations. Line length, and by inference, interline separation also had effect of the nature of the response.     

Vitamin D receptor expression, 24-hydroxylase activity, and inhibition of growth by 1alpha,25-dihydroxyvitamin D3 in seven human prostatic carcinoma cell lines

Although prostatic cancer is often viewed as an androgen-dependent malignancy, a number of other hormones including 1alpha, 25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] are now recognized to modulate its growth and differentiated phenotype. Seven different continuous human prostatic carcinoma cell lines were examined for the presence of biologically active receptors for 1alpha,25(OH)2D3. All seven lines were found to contain mRNA for the vitamin D receptor using an RNase protection assay. Six of the seven cell lines were found to have high-affinity saturable binding sites for 1alpha,25(OH)2D3. The seventh line was found to contain vitamin D receptors by sucrose gradient analysis. All seven lines were found to express 24-hydroxylase activity by a HPLC assay that measures the conversion of 25-hydroxyvitamin D3 to 24,25-dihydroxyvitamin D3. 24-Hydroxylase activity was up-regulated in all seven cell lines by preincubation with 1alpha,25(OH)2D3. In the presence of fetal bovine serum, the growth of four of the seven cell lines was inhibited. In the majority of cell lines growth inhibition was related not only to the number of receptors per cell, but also in inverse proportion to the 24-hydroxylase activity of each cell line. The ubiquitous presence of vitamin D receptor and 24-hydroxylase activity in human prostatic carcinoma cells suggests new alternatives for the pharmacological treatment of advanced prostatic cancer and implies that chemoprevention strategies could also make use of this endocrine axis.     

电感耦合等离子体原子发射光谱法测定钒钛铁精矿中的钒钛铝镁锰

提出了用电感耦合等离子体原子发射光谱法（ICP-AES）测定钒钛铁精矿中钒钛铝镁锰。以无水碳酸钠和四硼酸钠为熔剂,在1 000 ℃的温度下将试样熔融15～20 min,然后用体积分数为10% HCl浸取熔融物,浸出液中的钒、钛、铝、镁和锰用ICP-AES法测定。对浸取样品的酸种类及浓度进行了试验,最终选择了体积分数10%的盐酸。考察了5种元素的谱线并选择灵敏度高、基体无干扰或干扰很小的谱线作为分析谱线。制作校准曲线时采用基体匹配的方法消除基体干扰。依据所建立的方法对标准样品（GBW07227、BH0101）分别测定10次,测定结果的准确度和精确度均较好,相对标准偏差（n =10）在0.59%-4.8%范围内。此外,用该方法测定从生产原料中抽取的10个样品,测定结果与化学分析方法的测定结果一致。     

Group size, prior experience, and conformity.

An effort was made to validate the findings of 2 previous workers regarding the effect of the size of a group (Asch, 1952) and prior experience (Mausner, 1953, 1954, 1957) upon conformity in the judgment of the length of lines. The results of Asch and Mausner were reproduced; there is a curvilinear relationship between size of a group (from 2 to 5) and influence on S to conform to what he believes are the estimates of the lines made by others. Prior experience in making judgments of the lines was also found to influence the accuracy of judgment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of preparation, staining and microscopic techniques for counting incremental lines in cementum of human teeth

Apposition of cementum occurs in phases resulting in two types of layers with different optical and staining properties that can be observed by light microscopy. Narrow, dark staining incremental lines are separated by wider bands of pale staining cementum. The distance from one line to the next represents a yearly increment deposit of cementum in many mammals, and counting these lines has been used routinely to estimate the age of the animals. Incremental lines in cementum have also been observed in sections of human teeth, and the object of the present investigation was to examine a number of methods for preparing and staining them for counting. Longitudinal and transverse sections, either ground or decalcified, were cut from formalin fixed human dental roots, paraffin embedded or frozen, and stained using several techniques. The cementum was investigated using conventional light, fluorescence, polarized light, confocal laser scanning, interference contrast, phase contrast, and scanning electron microscopy. Incremental lines in the cementum could be observed in ground sections and, following decalcification, in both frozen and paraffin embedded sections. Toluidine blue, cresyl violet, hematoxylin, or periodic acid Schiff (PAS) stained incremental lines allowing differentiation by conventional light microscopy. Contrast was best using fluorescence microscopy and excitation by green light since the stained cemental bands, but not the incremental lines, fluoresced after staining with cresyl violet, PAS or hematoxylin and eosin. The results with other microscopic techniques were unsatisfactory. Since incremental lines are not destroyed by acids and stain differently than the remaining cementum, it is likely that they possess an organic structure which differs from the cementum. Incremental lines in human dental cementum could be observed best using decalcified sections stained with cresyl violet excited by green light.     

Neonatology in Europe. Training, accreditation, and research

PURPOSE: To correlate cellular glutathione content and gamma-glutamyl cysteine synthetase (gamma GCS) mRNA expression with cisplatin sensitivity in a panel of seven head and neck squamous cancer cell lines. METHODS: Cisplatin IC50 was determined for each cell line using a sodium tetreazolium (XTT) assay. Cellular glutathione content was measured by using a previously reported enzymic method. gamma GCS mRNA expression was measured using an RNase protection assay. RESULTS: Total cellular glutathione was an excellent predictor of cisplatin sensitivity in this series of cell lines. The IC50 for cisplatin in the cell line with the highest glutathione concentration was approximately 90 times higher than in the cell line with the lowest glutathione concentration. Regression analysis showed a highly statistically significant positive correlation between cisplatin IC50 and cellular glutathione (coefficient of determination R2 = 0.81, P = 0.0012). Some-what surprisingly, in contrast to previous studies in ovarian cancer, gamma GCS mRNA expression in these cell lines was not significantly predictive of either total cellular glutathione or cisplatin sensitivity (R2 = 0.005, P = 0.84). As expected, treatment of resistant cell lines with buthionine sulfoximine resulted in decreased cellular glutathione and enhanced cisplatin sensitivity. CONCLUSIONS: Our results suggest that glutathione may be an important determinant of cisplatin sensitivity in clinical head and neck cancer. Since cisplatin is the most active chemotherapy drug for the treatment of this disease, this correlation may have important clinical relevance. The lack of correlation between glutathione level and gamma GCS expression suggests that salvage or alternate synthetic pathways may be critical in these cells.     

Responses to various selection protocols for lamb production in Rambouillet, Targhee, Columbia, and Polypay sheep

To investigate the effectiveness of four selection protocols for improving reproduction in sheep, we evaluated nine selection lines and two random-bred control lines for lamb and wool production. Results were based on 25,026 dam and 30,628 lamb records from Rambouillet (R), Targhee (T), Columbia (C), and Polypay (P) sheep collected from 1976 through 1988. Phenotypic trends over years were positive (P < .01) for most reproductive traits, body weight, wool grade (coarser grades), and lamb weaning weight in nearly all selected lines. Small positive trends for both random-bred control lines indicated there were improvements in management and(or) environment during the period. Small but significant phenotypic declines in fleece weights occurred in most lines, including controls. Substantial genetic gains (P < .01) in litter weight weaned (120 d), net reproductive rate (lambs weaned divided by ewes mated), prolificacy, body weight, and weaning weight were made in nearly all selected lines. There were also small but significant improvements in milk score in most lines. There were significant genetic declines and improvements in fleece weights; however, the average genetic change in fleece weight for lines selected for litter weight weaned was negligible. Genetic improvement in litter weight weaned was attributed approximately 37% to prolificacy, 27% to percentage of lambs weaned, 17% to lamb weaning weight, 12% to fertility, and 7% to ewe viability from breeding to lambing. On average, selection based on independent culling levels (litter weight weaned plus yearling body weight), yearling body weight, or early puberty was only 85, 67, or 59%, respectively, as effective as that based solely on litter weight weaned for improving litter weight weaned. The net value of the average (over all breeds) annual increase in production per ewe resulting from selection for litter weight weaned accumulated over 12 yr to an estimated $11.40 and $21.51 annually for genetic and phenotypic increases, respectively.