نتایج جستجو برای: water and urea
تعداد نتایج: 16934169 فیلتر نتایج به سال:
objective: the objective of this study was to investigate the invitro fluoride release of four new self-adhesive resin cements; set (sdi, australia), breeze (pentron, usa), embrace wetbond (pulpdent, usa), g-cem (gc, japan) and to assess the bonding performance of these self-adhesive resin cements for bonding of orthodontic brackets. materials and methods: for fluoride release experiment, six ...
We use polarization-resolved mid-infrared pump-probe spectroscopy to study the effect of urea on the structure and dynamics of water. Surprisingly, we find that, even at high concentrations of urea (8 M), the orientational dynamics of most water molecules are the same as in pure liquid water, showing that urea has a negligible effect on the hydrogen-bond dynamics of these molecules. However, a ...
Introduction: Simultaneous development of technology is composed with environmental hazardous with heavy-metals and organic solvents and thus toxic catalysts/organic solvents must be replaced with biocatalysts and water. Urease is a hydrolase enzyme and urease-urea can be considered a safe source of toxic ammonia in synthesis of nifedipine. Nifedipine is an antihypertensive drug synthesized by ...
Elasmobranchs such as the dogfish shark Squalus acanthius achieve osmotic homeostasis by maintaining urea concentrations in the 300- to 400-mM range, thus offsetting to some degree ambient marine osmolalities of 900-1,000 mosmol/kgH(2)O. These creatures also maintain salt balance without losing urea by secreting a NaCl-rich (500 mM) and urea-poor (18 mM) fluid from the rectal gland that is isot...
in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...
The structural and energetic properties of solutions containing water, urea, and trimethylamine-N-oxide (TMAO) are examined using molecular dynamics simulations. Such systems are of interest mainly because TMAO acts to counter the protein denaturing effect of urea. Even at relatively high concentration, TMAO is found to fit well into the urea-water structure. The underlying solution structure i...
Salicylic acid (SA) is a phyto-hormone that regulates physiological and biological processes in plants and can be used to improve plant growth under different environmental conditions, including water stress. Thus, a field experiment as split plot factorial based on randomized complete blocks design with three replications was conducted in 2014 to investigate the effects of fertilizer and salic...
Salicylic acid (SA) is a phyto-hormone that regulates physiological and biological processes in plants and can be used to improve plant growth under different environmental conditions, including water stress. Thus, a field experiment as split plot factorial based on randomized complete blocks design with three replications was conducted in 2014 to investigate the effects of fertilizer and salic...
Transfer energetics from pure water to a urea-water mixture is examined for a set of amino acid analog solutes by using molecular dynamics simulation and free-energy calculation. The free energy of transfer from pure-water solvent to 8 M urea-water mixed solvent is calculated for each solute, and the urea-water mixture is shown to be a more favorable solvent than pure water. The correlation of ...
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