scholarly journals Flue Gas Desulphurization at Low Temperatures Using Coal Fly Ash/Ca-Based Sorbent: Determination of Rate Limiting Step

2011 ◽  
Vol 1 ◽  
pp. 1-10 ◽  
Author(s):  
Henry Foo ◽  
Lee Keat Teong ◽  
Noel Fernando ◽  
Abdul Rahman Mohamed
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Low Temperatures ◽  
Coal Fly Ash ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting ◽  
Flue Gas Desulphurization

scholarly journals DETERMINATION OF l-HISTIDINE IN NANOGRAM AMOUNTS AND THE QUESTION OF ITS OCCURRENCE IN MAST CELLS

1972 ◽  
Vol 20 (11) ◽  
pp. 917-922 ◽  
Author(s):  
DAVID I. WILKINSON ◽  
DAVID GLICK
Keyword(s):  
Mast Cells ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Peritoneal Mast Cells ◽  
Before And After ◽  
Chromatographic Detection ◽  
Rat Peritoneal Mast Cells ◽  
Rate Limiting

In an attempt to clarify the question of whether histidine is stored in the mast cell for coversion to histamine or whether the rate of conversion is rapid enough to prevent accumulation of histidine so that the rate-limiting step is the histidine uptake, it was found that no histidine was demonstrable in rat peritoneal mast cells by either quantitative analysis or paper chromatographic detection. Microadaptation of Hassall's method, based on conversion of l-histidine by histidase to urocanic acid and measurement of the latter by its absorbance at 277 nm, was made to permit determination of histidine in nanogram amounts in the presence of histamine. This adaptation was found reliable when compared with the o-phthalaldehyde method in estimation of l-histidine in serum and in insulin hydrolysate, and then it was applied to analysis of mast cells before and after l-histidine uptake in vitro. The adaptation should be generally useful in microanalysis of l-histidine in histologically and cytologically defined samples.

Determination of the Isotope Effect of the Enzymatic Oxidation of (R)Carnitine by Displacement of the Equilibrium via Mass Action

1975 ◽  
Vol 30 (7-8) ◽  
pp. 438-441
Author(s):  
Klaus Brendel ◽  
Rubin Bressler ◽  
Miguel A. Alizade
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Isotope Effect ◽  
Mass Action ◽  
Enzymatic Oxidation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Different Temperatures ◽  
Acid Hydrochloride ◽  
Rate Limiting

Abstract An isotope effect of the dehydrogenation of (R) Carnitine [(R) 3-hydroxy-4-trimethylamino-butyric acid hydrochloride] catalyzed by (R) carnitine dehydrogenase [(R) carnitine: NAD oxido-reductase E.C. 1.1.1.108] from Pseudomonas aeruginosa was measured at different temperatures. It was found that k1H/k3H does not vary greatly with changes of temperature. The value of 3 for k1H/k3H measured at small initial conversions strongly indicated that the rate limiting step of the oxidation of (R) carnitine is the cleavage of the C-H bond at C3.

Phosphorylation of Ca-ATPase of Sarcoplasmic Reticulum with Different Substrates

1983 ◽  
Vol 38 (9-10) ◽  
pp. 845-847 ◽  
Author(s):  
Hector Barrabin ◽  
Leopoldo de Meis
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Low Temperatures ◽  
Hplc Analysis ◽  
Calcium Concentration ◽  
Specific Activity ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
High Calcium ◽  
High Calcium Concentration ◽  
Rate Limiting

ATP and GTP as substrate for phosphorylation of sarcoplasmic reticulum ATPase are compared. Maximal levels of phosphoenzyme are between 4.5 and 4.8 nmol per mg of protein when either substrate is used provided that phosphoenzyme hydrolysis are strongly inhibited by high calcium concentration (20 mм) and low temperatures ( 0 ° C ) . The maximal values obtained with GTP are lower than those previously reported. It is shown that this difference is due to underestimation of the specific activity of labeled nucleotides used in previous studies, as revealed by UV absorption and HPLC analysis. The dependence of the phosphoenzyme levels on calcium concentration, pH and temperature confirm previous findings indicating that ATP, but no GTP, accelerates the rate limiting step of the catalytic cycle.

scholarly journals Mass Transfer Studies on Adsorption of Phenol from Wastewater UsingLantana camara, Forest Waste

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
C. R. Girish ◽  
V. Ramachandra Murty
Keyword(s):  
Mass Transfer ◽  
Lantana Camara ◽  
Model Parameters ◽  
External Mass Transfer ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Forest Waste ◽  
Mass Transfer Studies ◽  
Rate Limiting

Adsorption is one of the important treatment methods for the removal of pollutants from wastewater. The determination of rate controlling step in the process is important in the design of the process. Therefore, in the present work, mass transfer studies were done to evaluate the rate-limiting step in the adsorption of phenol from aqueous solution ontoLantana camara. Different mass transfer models were used to find the rate-limiting step and also to find the values of external mass transfer coefficient and diffusion coefficient. The Biot number was found to investigate the importance of external mass transfer to intraparticle diffusion. From the various models studied and the Biot numbers obtained, it was found that the adsorption onLantana camarawas controlled by film diffusion. The sensitivity analysis was performed to study the significance of the model parameters on the adsorption process.

scholarly journals Synthesis and Characterization of Zeolites Produced from Low-Quality Coal Fly Ash and Wet Flue Gas Desulphurization Wastewater

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1558
Author(s):  
Paulina Nowak ◽  
Barbara Muir ◽  
Agnieszka Solińska ◽  
Małgorzata Franus ◽  
Tomasz Bajda
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Coal Fly Ash ◽  
Environmental Pollutants ◽  
Textural Properties ◽  
Solution Concentration ◽  
Sorption Properties ◽  
X Ray ◽  
Synthetic Zeolites ◽  
Flue Gas Desulphurization

This study investigated a low-energy-consuming procedure for the synthesis of zeolite materials from coal fly ash (CFA). Materials containing zeolite phases, namely Na–X, Na–P1, and zeolite A, were produced from F–class fly ash, using NaOH dissolved in distilled water or in wastewater obtained from the wet flue gas desulphurization process, under atmospheric pressure at a temperature below 70 °C. The influence of temperature, exposure time, and alkaline solution concentration on the synthesized materials was tested. In addition, chemical, mineralogical, and textural properties of the obtained materials were determined by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and cation exchange capacity (CEC). Cd(II), Ni(II), NH4+ cation, and Se(VI) anion sorption experiments were conducted to compare the sorption properties of the produced synthetic zeolites with those of the commercially available ones. Zeolitization resulted in an increase of CEC (up to 30 meq/100 g) compared to raw CFA and enhanced the ability of the material to adsorb the chosen ions. The obtained synthetic zeolites showed comparable or greater sorption properties than natural clinoptilolite and synthetic Na–P1. They were also capable of simultaneously removing cationic and anionic compounds. The structural, morphological, and textural properties of the final product indicated that it could potentially be used as an adsorbent for various types of environmental pollutants.

scholarly journals Mechanism of Up-regulation of Starch Synthesis in Mature Leaves of Transgenic Apple Trees with Decreased Sorbitol Synthesis

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1009D-1009
Author(s):  
Rui Zhou ◽  
Lailiang Cheng ◽  
Abhaya Dandekar
Keyword(s):  
Transgenic Plants ◽  
Starch Synthesis ◽  
Redox Status ◽  
Mature Leaves ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting ◽  
Transgenic Apple ◽  
Hexose Phosphates

The reaction catalyzed by ADP-glucose pyrophosphorylase (AGPase) to form ADP-glucose is a regulatory and rate-limiting step in starch synthesis in plants. In response to decreased sorbitol synthesis, starch synthesis was up-regulated in the transgenic apple plants. In this study, we examined both redox and metabolite regulation of AGPase to understand the mechanism responsible for the up-regulation of starch synthesis. No difference in the monomerization/dimerization of apple leaf AGPase small subunits was observed between the transgenic plants and the untransformed control. NADP-dependent malate dehydrogenase, indicative of chloroplastic redox status, did not show significant change in the transgenic plants either. Determination of key metabolites with nonaqueous fractionation indicated that concentrations of hexose phosphates (mainly glucose-6-phosphate and fructose-6-phosphate) were higher in both the cytosol and chloroplasts of the transgenic plants than in the control, whereas 3-phosphoglycerate (PGA) concentration in the chloroplast was not higher in the transgenic plants. We conclude that accumulation of hexose-phosphates results in a decrease in inorganic phosphate (Pi) concentration and an increase in PGA/Pi ratio in the chloroplast, leading to up-regulation of starch synthesis via activating AGPase.

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