نتایج جستجو برای: phosphorus compounds

تعداد نتایج: 265774  

Arsenic is considered as one of the most important environmental contaminant elements. Some plant species can grow in arsenic contaminated soils and they are able to reduce arsenic toxicity. In this study, a hydroponic experiment was conducted on Isatis cappadocica, a newly-discovered As hyperaccumulator. Accordingly, we conducted this experiment to compare the interaction of effect of arsenic ...

Journal: :Clinical journal of the American Society of Nephrology : CJASN 2010
Orlando M Gutiérrez

The discovery of fibroblast growth factor 23 (FGF23) has clarified much of our understanding of abnormalities in phosphorus and vitamin D metabolism in chronic kidney disease (CKD). FGF23 is a bone-derived hormone that promotes phosphaturia and decreases the synthesis of 1,25-dihydroxyvitamin D (1,25(OH)(2)D). The primary systemic stimuli of FGF23 secretion are increased 1,25(OH)(2)D levels and...

2014
Nils G Holm

Procedures for the analysis of phosphorus in geological material normally aims for the determination of the total amount of P expressed as orthophosphate [Formula: see text] or the differentiation between inorganic and organic P. This is probably due to analytical difficulties but also to the prevalent opinion that the chemistry of phosphorus in geological environments is almost entirely restri...

2014
Elisabet Öberg Andreas Orthaber Christophe Lescop Régis Réau Muriel Hissler Sascha Ott

Phosphole-substituted phosphaalkenes (PPAs) of the general formula Mes*P=C(CH(3))-(C(4)H(2)P(Ph))-R 5 a-c (Mes*=2,4,6-tBu(3)Ph; R=2-pyridyl (a), 2-thienyl (b), phenyl (c)) have been prepared from octa-1,7-diyne-substituted phosphaalkenes by utilizing the Fagan-Nugent route. The presence of two differently hybridized phosphorus centers (σ(2) ,λ(3) and σ(3) ,λ(3)) in 5 offers the possibility to s...

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...

1999
LAURENCE IRVING PHILLIP H. WELLS

Since Engelmann’s (1871) demonstration of increased phosphorus excretion in urine secreted during muscular exercise, there have been many attempts to show that the increase originated in the muscles. Muscle phosphorus compounds remain obscure, and it has only been during the last 10 years that the inorganic phosphorus of tissues could be conveniently determined. During this period, tissue inorg...

2014
Maheen Gull

Phosphorus (P) is an essential element for life. It occurs in living beings in the form of phosphate, which is ubiquitous in biochemistry, chiefly in the form of C-O-P (carbon, oxygen and phosphorus), C-P, or P-O-P linkages to form life. Within prebiotic chemistry, several key questions concerning phosphorus chemistry have developed: what were the most likely sources of P on the early Earth? Ho...

Journal: :Plant physiology 1968
R L Bieleski

The duckweed Spirodela oligorrhiza was grown in sterile nutrient solutions that contained 1 mm phosphate-(32)P at various specific activities. In solutions with activities higher than 2 muc per mumole per ml, plant growth was inhibited after a time, and the physical appearance of the plants was affected. The critical level of radiation, at which growth was first affected, corresponded to 5 kilo...

Journal: :Physical chemistry chemical physics : PCCP 2015
Shamil K Latypov Fedor M Polyancev Dmitry G Yakhvarov Oleg G Sinyashin

The aim of this work is to convince practitioners of (31)P NMR methods to regard simple GIAO quantum chemical calculations as a safe tool in structural analysis of organophosphorus compounds. A comparative analysis of calculated GIAO versus experimental (31)P NMR chemical shifts (CSs) for a wide range of phosphorus containing model compounds was carried out. A variety of combinations (at the HF...

Journal: :Cancer research 1946
W C SCHNEIDER H L KLUG

Malignant tissues are distinguished from other types of tissues by their capacity for relatively unlimited and uncontrolled growth in the organism. The reason why neoplastic tissues grow continually, in contrast to embryonic tissues which grow only up to a certain point before they begin to differentiate, is a fundamental problem of cancer research. A study of the synthetic mechanisms of the ce...

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