Determination of daminozide in apples by gas chromatography/chemical ionization mass spectrometry   总被引：2，自引：0，他引：2  

C H Liu  G C Mattern  G M Singer  J D Rosen 《Journal of the Association of Official Analytical Chemists》1989,72(6):984-986

A method using gas chromatography/chemical ionization mass spectrometry (GC/CIMS) for the determination of daminozide residues in apples has been developed. Daminozide was separated from the sample matrix by water extraction and cation exchange, converted to the methyl ester by treatment with HCl-methanol, and determined by GC/CIMS using succinonitrile as an internal standard. The detection level was 0.05 ppm. Recoveries were 92-104% from apples spiked at the 0.05-0.5 ppm levels. Of the 25 apple samples analyzed, only 2 were positive for daminozide (1.04 and 0.32 ppm).  相似文献   

Automated sample cleanup for pesticide multiresidue determination. I. Evaluation of solvent partitioning module     

F M Gretch  J D Rosen 《Journal of the Association of Official Analytical Chemists》1984,67(1):108-111

An automated continuous flow procedure is described that improves the cost effectiveness and precision of AOAC methodology for multiresidue pesticide determinations in nonfatty foods. Individual modules capable of performing automated solvent partitioning and automated column chromatography were constructed and integrated into a continuous flow system. Data are presented comparing the recoveries and precision for the determination of 8 pesticides (aldrin, dieldrin, p,p'-DDT, ethion, heptachlor epoxide, lindane, parathion, and ronnel) partitioned from 2 food crops (spinach and tomatoes) by both the manual and automated procedures.  相似文献   

地下水埋深对春玉米田土壤水分及产量的影响   总被引：17，自引：3，他引：17  

巴比江郑大玮  卡热玛·哈木提　孟翀王占生  邱江泉 《水土保持学报》2004,18(3):57-60,65

通过6种地下水位控制处理和对照春玉米试验,探讨了地下水埋深对春玉米农田土壤水分、产量以及水分利用效率的影响。结果表明,地下水埋深对春玉米0～100cm层次土壤水分的影响较大。地下水位越浅这种影响显得越明显;无论地下水埋深深浅,田间累计地下水补给量变化规律可分为4个阶段,即稳定增长期、缓慢增长期、快速增长期和趋于稳定期。地下水位越高,累计地下水补给量越大,土壤排水量越大。较大降雨后土壤开始排水日期随着地下水埋深加深而滞后;地下水埋深1.0m时春玉米产量和水分利用率最高。地下水位在1.0m以下时,水分利用效率随地下水位加深而减少。  相似文献   

Characterization of flavonols in cranberry (Vaccinium macrocarpon) powder     

Vvedenskaya IO  Rosen RT  Guido JE  Russell DJ  Mills KA  Vorsa N 《Journal of agricultural and food chemistry》2004,52(2):188-195

Flavonoids were extracted from cranberry powder with acetone and ethyl acetate and subsequently fractionated with Sephadex LH-20 column chromatography. The fraction eluted with a 60% methanol solution was composed primarily of phenolic constituents with maximum absorbance at 340 nm. A high-performance liquid chromatography procedure was developed, which resolved 22 distinct peaks with UV/vis and mass spectra corresponding to flavonol glycoside conjugates. Six new constituents not previously reported in cranberry or in cranberry products were determined through NMR spectroscopy to be myricetin-3-beta-xylopyranoside, quercetin-3-beta-glucoside, quercetin-3-alpha-arabinopyranoside, 3'-methoxyquercetin-3-alpha-xylopyranoside, quercetin-3-O-(6' '-p-coumaroyl)-beta-galactoside, and quercetin-3-O-(6' '-benzoyl)-beta-galactoside. Quercetin-3-O-(6' '-p-coumaroyl)-beta-galactoside and quercetin-3-O-(6' '-benzoyl)-beta-galactoside represent a new class of cranberry flavonol compounds with three conjugated components consisting of a flavonol, sugar, and carboxylic acid (benzoic or hydroxycinnamic acids). This is also the first report identifying quercetin-3-arabinoside in both furanose and pyranose forms in cranberry. Elucidation of specific flavonol glycosides in cranberry is significant since the specificity of the sugar moiety may play a role in the bioavailability of the flavonol glycosides in vivo.  相似文献   

重齿小蠹聚集信息素诱捕器的应用技术研究     

陈国发  王艳军  巴达玛  刘广田  周孝明  白永安  牛景富  韩静波  牛月英 《辽宁林业科技》2011,(3):15-17,60

重齿小蠹对人工合成聚集信息素的昼夜反应节律发生在白天7：00～21：00,反应高峰在14：00-19：00,反应模式为＂单峰式—白天型＂;利用人工合成的聚集信息素对重齿小蠹成虫发生期监测表明,成虫扬飞的开始时间为5月20日左右,扬飞高峰期为6月下旬和7月上旬,扬飞末期为8月26日,成虫扬飞的持续期为98 d。2007-2009年大量诱杀防治的试验前、后重齿小蠹致死木平均分别为3.39株/hm2和0.76株/hm2,致死木减少了77.58%,而对照区试验前、后致死木平均分别为15.89株/hm2和18.11株/hm2,致死木增加了13.97%,3 a大量诱杀试验的防治效果显著。  相似文献   

Ecdysteroids of quinoa seeds (Chenopodium quinoa Willd.)     

Zhu N  Kikuzaki H  Vastano BC  Nakatani N  Karwe MV  Rosen RT  Ho CT 《Journal of agricultural and food chemistry》2001,49(5):2576-2578

Quinoa (Chenopodium quinoa) is a hardy and nutritious Latin American pseudo-cereal. Studies on the seeds led to the isolation of five ecdysteroids using column chromatography. Their structures were determined as ecdysterone, makisterone A, 24-epi-makisterone A, 24(28)-dehydromakisterone A, and 20,26-dihydroxyecdysone by spectroscopic methods. This study demonstrates that quinoa seeds are a source of ecdysteroids, which were reported to be molting hormones in insects.  相似文献   

电控发动机尾气检测与故障诊断的研究     

李友才  巴寅亮  林盛长 《新疆农业大学学报》2006,29(3):105-107

为寻求根据汽车尾气参数来诊断汽车故障的方法，利用径向基函数（RBF）神经网络，对丰田雷克萨斯（LEXUS）400电控发动机进行故障诊断研究。研究结果表明，径向基函数神经网络对发动机故障的诊断是迅速、准确的。  相似文献   

THE DEVELOPMENT OF THE PHYLLOXERA VASATRIX LEAF GALL     

Rosen HR 《Science (New York, N.Y.)》1916,43(1102):216-217

  相似文献   

After insulin binds   总被引：54，自引：0，他引：54  

O M Rosen 《Science (New York, N.Y.)》1987,237(4821):1452-1458

Three recent advances pertinent to the mechanism of insulin action include (i) the discovery that the insulin receptor is an insulin-dependent protein tyrosine kinase, functionally related to certain growth factor receptors and oncogene-encoded proteins, (ii) the molecular cloning of the insulin proreceptor complementary DNA, and (iii) evidence that the protein tyrosine kinase activity of the receptor is essential for insulin action. Efforts are now focusing on the physiological substrates for the receptor kinase. Experience to date suggests that they will be rare proteins whose phosphorylation in intact cells may be transient. The advantages of attempting to dissect the initial biochemical pathway of insulin action include the wealth of information about the metabolic consequences of insulin action and the potential for genetic analysis in Drosophila and in man.  相似文献   

Replicative and cytopathic potential of HTLV-III/LAV with sor gene deletions   总被引：42，自引：0，他引：42  

J Sodroski  W C Goh  C Rosen  A Tartar  D Portetelle  A Burny  W Haseltine 《Science (New York, N.Y.)》1986,231(4745):1549-1553

The genome of the human T-lymphotropic virus type III (HTLV-III/LAV) has the potential to encode at least three polypeptides in addition to those encoded by the gag, pol, and env genes. In this study, the product of the sor (short open reading frame) region, which overlaps the 3' end of the pol gene, was found to be a protein with a molecular weight of 23,000. An assay was developed for testing the ability of cloned HTLV-III proviruses to produce viruses cytopathic for T4+ lymphocytes. In the cell line used, C8166, neither the HTLV-III sor gene product nor the complete 3'-orf gene product were necessary for the replication or cytopathic effects of the HTLV-III.  相似文献