نتایج جستجو برای: cr

تعداد نتایج: 45657  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ولی عصر (عج) - رفسنجان - دانشکده ادبیات و علوم انسانی 1393

the present study investigated construct equivalence of multiple choice (mc) and constructed response (cr) item types across stem and content equivalent mc and cr items (item type ‘a’), non-stem-equivalent but content equivalent mc and cr items (item type ‘b’), and non-stem and non-content equivalent mc and cr items (item type ‘c’). one hundred seventy english-major undergraduates completed mc ...

2014
Zachary DeLoughery Michal W. Luczak Anatoly Zhitkovich

Cr(VI) genotoxicity is caused by products of its reductive metabolism inside the cells. Reactive oxygen species (ROS) and Cr(V,IV) intermediates are potential sources of oxidative damage by Cr(VI). Here, we investigated seven fluorescent probes for the detection of ROS and non-ROS oxidants in Cr(VI) reactions with its main reducers. We found that Cr(V)-skipping metabolism of Cr(VI) by ascorbate...

2013
Anil C. Somenahally Jennifer J. Mosher Tong Yuan Mircea Podar Tommy J. Phelps Steven D. Brown Zamin K. Yang Terry C. Hazen Adam P. Arkin Anthony V. Palumbo Joy D. Van Nostrand Jizhong Zhou Dwayne A. Elias

Microbial reduction of toxic hexavalent chromium (Cr(VI)) in-situ is a plausible bioremediation strategy in electron-acceptor limited environments. However, higher [Cr(VI)] may impose stress on syntrophic communities and impact community structure and function. The study objectives were to understand the impacts of Cr(VI) concentrations on community structure and on the Cr(VI)-reduction potenti...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز - دانشکده کشاورزی 1389

چکیده: آلودگی کروم در خاک و آب های زیرزمینی به عنوان یک مشکل جدی زیست محیطی محسوب می شود. دو حالت اکسایشی پایدار کروم (iii و vi) در طبیعت یافت می شوند. کروم شش ظرفیتی (cr(vi)) کاملاً محلول و متحرک بوده و به دلیل داشتن خواص اکسید کنندگی قوی، اثرات سمّی در سیستم های زیستی دارد در حالیکه کروم سه ظرفیتی (cr(iii)) به دلیل شرکت در سوخت و ساز گلوکز، چربی و پروتئین، به عنوان یک عنصر ضروری برای حیوانات ش...

2015
Esther S. Posner Richard Hervig

The Mn–Cr decay system, in which Mn decays to Cr (t1/2 = 3.7 Ma) has been widely used to construct Cr/Cr vs. Mn/Cr isochrons and thus determine relative ages of early solar system objects or events, assuming that the initial Cr isotopic ratio, (Cr/Cr)o, equals ( Mn/Cr)o. With the primary objective of interpretation of these ages within a diffusion kinetic framework, we have determined the trace...

Journal: :Journal of animal science 2002
J L G van de Ligt M D Lindemann R J Harmon H J Monegue G L Cromwell

A total of 60 pigs from 15 litters were used during two experiments to assess the effects of maternal supplementation of Cr tripicolinate on performance and immune status of the offspring during the first 42 d after weaning. Gilts were raised on diets with either 0 (-Cr) or 200 (+Cr) ppb supplemental Cr from Cr tripicolinate. Their offspring were weaned at about 23 d of age. Pigs from dams fed ...

Journal: :Dalton transactions 2016
Chen Dong Genhua Wu Zhuqing Wang Wenzhi Ren Yujie Zhang Zheyu Shen Tianhua Li Aiguo Wu

A colorimetric assay is proposed for the selective detection of Cr(iii) and Cr(vi) via the aggregation-induced color change of gallic acid capped gold nanoparticles (GA-AuNPs). The AuNPs are characterized using UV-vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and Fourier-transform infrared spectrometry (FT-IR). To detect Cr(iii) and Cr(vi) coexisting i...

2015
Chiara Ciaccio Francisco Ocaña-Calahorro Enrica Droghetti Grazia R. Tundo Emanuel Sanz-Luque Fabio Polticelli Paolo Visca Giulietta Smulevich Paolo Ascenzi Massimo Coletta Rajagopal Subramanyam

The single-cell green alga Chlamydomonas reinhardtii harbors twelve truncated hemoglobins (Cr-TrHbs). Cr-TrHb1-1 and Cr-TrHb1-8 have been postulated to be parts of the nitrogen assimilation pathway, and of a NO-dependent signaling pathway, respectively. Here, spectroscopic and reactivity properties of Cr-TrHb1-1, Cr-TrHb1-2, and Cr-TrHb1-4, all belonging to clsss 1 (previously known as group N ...

Journal: :Carcinogenesis 2006
Hirohumi Arakawa Feng Wu Max Costa William Rom Moon-Shong Tang

Hexavalent chromium [Cr(VI)] is a known etiological factor in human lung cancer. Cr(VI) exposure-related lung cancer has a high mutation incidence in the p53 gene. Upon intake in human cells Cr(VI) is reduced to Cr(III), which is able to conjugate with amino acids and consequently form either binary Cr(III)-DNA or ternary Cr(III)-amino acid-DNA adducts. Both binary and ternary Cr(III)-DNA adduc...

Journal: :The Annals of occupational hygiene 2005
Rania A Sabty-Daily Patricia A Harris William C Hinds John R Froines

Spray painters are potentially exposed to aerosol containing Cr(VI) via inhalation of chromate-based paint spray. Two field studies were conducted at an aerospace facility to determine the size distribution and speciation of Cr(VI) in paint spray aerosol. Sampled paint products consisted of sparingly soluble strontium chromate in an epoxy resin matrix, a matrix generally known for its durabilit...

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