نتایج جستجو برای: trace organic compounds

تعداد نتایج: 463893  

Journal: :Annual review of marine science 2009
Julia M Vraspir Alison Butler

Marine microorganisms are presented with unique challenges to obtain essential metal ions required to survive and thrive in the ocean. The production of organic ligands to complex transition metal ions is one strategy to both facilitate uptake of specific metals, such as iron, and to mitigate the potential toxic effects of other metal ions, such as copper. A number of important trace metal ions...

Journal: :Journal of animal science 2008
J C Peters D C Mahan

Dietary trace mineral sources and levels were fed to developing gilts to evaluate their performance responses during the growth phase, but treatments were continued into the reproductive phase in which subsequent reproductive responses were evaluated. In Exp. 1, three groups of gilts (n = 216) were used in a 2 x 2 factorial in a randomized complete block design (6 replicates) with treatment die...

2018
Carola Fischer-Tenhagen Dorothea Johnen Irene Nehls Roland Becker

Early and reliable diagnostic test is essential for effective therapy of lung cancer. Volatile organic compounds that are characteristic for cancer could serve as valuable biomarkers in cancer diagnosis. Both trace analytical and detection dog approaches give some evidence for the existence of such biomarkers. In this proof of concept, study dogs and trace analysis were implemented in combinati...

2017
Mi-Sun Lee Ryan F. LeBouf Youn-Suk Son Petros Koutrakis David C. Christiani

BACKGROUND We aimed to assess the content of electronic cigarette (EC) emissions for five groups of potentially toxic compounds that are known to be present in tobacco smoke: nicotine, particles, carbonyls, volatile organic compounds (VOCs), and trace elements by flavor and puffing time. METHODS We used ECs containing a common nicotine strength (1.8%) and the most popular flavors, tobacco and...

2004
Ronit Nativ

Analyses of regional-scale synoptics and air-mass trajectories, local-scale atmospheric measurements (wind direction and speed, air temperature, dust load, SO 2 and NO x concentrations in the air, rain amount and intensity), and chemical and isotopic compositions of rainwater collected in the coastal city of Ashdod, Israel, were used to identify the various contributing sources to rainwater sal...

Journal: :Advances in space research : the official journal of the Committee on Space Research 2004
B V Peterson M Hummerick M S Roberts V Krumins A L Kish J L Garland S Maxwell A Mills

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In...

2015
Fan-xin Kong Hong-wei Yang Xiao-mao Wang Yuefeng F. Xie

The DSPM&DE (Donnan steric pore model and dielectric exclusion) model was employed to predict the rejection of six haloacetic acids (HAAs) and six pharmaceuticals (PhACs), selected to have different molecular weight, hydrophobicity and charge, by two commercial nanofiltration (NF) membranes (HL and NF270). Increasing filtration pressures were applied to vary the rejection ratios. Glucose and Na...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه شیمی و مهندسی شیمی ایران - پژوهشکده موادآلی و طبیعی 1389

در این پروژه ترکیبات 3-آریل-2h-بنزو[b]-4،1-اکسازین ها از مواد اولیه تجاری مشتقات دو آمینو فنول و ?-هالو کتون های آروماتیک در مایع یونی 1-اکتیل-3-متیل ایمیدازولیوم تترا فلورو بورات([omim]bf4) سنتز شده است. این واکنش توسط باز پتاسیم کربنات محلول از طریق o-آلکیلاسیون و سپس یک واکنش آمیداسیون درون مولکولی خود بخود در مدت زمان کوتاه انجام می شود. ترکیبات 4،1-بنزوکسازین به این روش با بهره خوب تا آلی ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
Matthew A Pasek Jacqueline M Sampson Zachary Atlas

The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine--PH3--a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs...

2005
Liva HARINANTENAINA

Mastigophorenes A—D (1—4) are dimeric herbertenetype sesquiterpenoids found only in the liverwort Mastigophora diclados (BRID.) NEES. They have usually been isolated with their precursor herbertenediol (5). Our recent investigation of a liverwort sample collected from Madagascar, however, did not show any trace of mastigophorenes A and B but revealed the presence of 3—5. The remarkable neurotro...

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