نتایج جستجو برای: determination of chemicals

تعداد نتایج: 21173121  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده مرتع و آبخیزداری و شیلات و محیط زیست 1391

مراتع حدود نیمی از خشکی های جهان را در بر دارند و پوشش گیاهی آن در نتیجه تأثیر متقابل محیط و موجودات زنده به وجود آمده است و به عنوان یک اکوسیستم طبیعی مدیریت می شوند. علاوه بر مراتع، راه ها در عصر حاضر نیز از اجزا مهم و زیرساخت های اصلی زندگی نوین و توسعه کشورها به شمار می روند. جاده ها ساخته دست بشر هستند و جوامع گیاهی کنار جاده تحت تأثیر ساخت و ساز قرار دارند. پوشش "رودرال" به مجموعه ای از پ...

Journal: :Applied sciences 2021

Lytic polysaccharide monooxygenases (LPMOs) consist of a class enzymes that boost the release oxidised products from plant biomass, in an approach is more eco-friendly than traditional ones, employing harsh chemicals. Since LPMOs are redox enzymes, they could possibly be exploited by immobilisation on electrode surfaces. Such requires knowledge kinetic and thermodynamic information for interact...

Journal: :پژوهش های علوم دامی 0
بهرام فتحی آچاچلویی میکائیل بدرزاده

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حکیمی , ابراهیم, محمدیان , محمود, میرمحمدی , سیدتقی, کامل , کامیار, کدیر, عمر ,

Background and Purpose: MDI (Methylene Diphenyl Diisocyanate) is a high tonnage product, which comprises about 90% of the total diisocyanate in the market. Polyurethanes are produced by reacting diisocyanate with polyols and other chemicals. They are known as respiratory tract and skin sensitizers and are the most common cause of occupational asthma in the world (NIOSH 1994). On this subject,...

2016
S. A. SAGANUWAN

Toxicity study is the investigation of either short or long-term toxic effects of a drug or chemical on animals. The toxicity is dose-dependent as asserted by Paracelsus over 500 years ago. However, short-term toxic effect is determined using median lethal dose (LD50) first introduced by Trevan in 1927 and revised many times. Presently there is a growing preponderance of rejection of scientific...

Journal: :Journal of chromatographic science 2006
Annamaria Halasz Jalal Hawari

Solid-phase microextraction (SPME) is an organic solvent-free sample preparation tool suitable for direct adsorption of analytes from the headspace or the aqueous phase of a matrix followed by desorption into a gas chromatograph (GC) or high-performance liquid chromatograph (HPLC) for subsequent analysis. The SPME technique is designed to accommodate the use of fibers coated with different poly...

Journal: :international journal of environmental research 2010
s. monavari

methods for measuring toxicity or respiratory activity of microbial cultures can be used as tools for assessing the presence of chemicals and their impact on the streams. the proposed toxicity test is based on the respirometric characteristics of the bacteria according to the principals of biolog’s microplate system. as the microorganism are utilizing the carbon source (peptone), the reductio...

Journal: :Current pharmaceutical design 2007
S Bremer C Pellizzer S Hoffmann T Seidle T Hartung

Large scale toxicological testing programmes which are currently ongoing such as the new European chemical legislation REACH require the development of new integrated testing strategies rather than applying traditional testing schemes to thousands of chemicals. The current practice of requiring in vivo testing for every possible adverse effect endanger the success of these programmes due (i) to...

Journal: :Journal of agricultural and food chemistry 2006
Million Bekele Woudneh Daniel Ray Oros

A new method for determination of pyrethroids, pyrethrins, and piperonyl butoxide (PBO) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was developed for surface water samples. The method is based on sampling 100 L of ambient surface water with a solid phase extraction (SPE) technique that uses both wound glass fiber filters for collecting the particulate-ass...

Journal: :Regulatory toxicology and pharmacology : RTP 2011
Remi Bars Fabrice Broeckaert Ivana Fegert Melanie Gross Nina Hallmark Tim Kedwards Dick Lewis Sue O'Hagan Grace H Panter Lennart Weltje Arnd Weyers James R Wheeler Malyka Galay-Burgos

The European legislation on plant protection products (Regulation (EC) No. 1107/2009) and biocides (Directive 98/8/EC), as well as the regulation concerning chemicals (Regulation (EC) No. 1907/2006 'REACH') only support the marketing and use of chemical products on the basis that they do not induce endocrine disruption in humans or non-target species. However, there is currently no agreed guida...

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