The relationship between creatine kinase kinetics and exercise intensity in human forearm is unchanged by age

2000 ◽  
Vol 279 (2) ◽  
pp. E333-E339 ◽  
Author(s):  
A. Horská ◽  
K. W. Fishbein ◽  
J. L. Fleg ◽  
R. G. S. Spencer
Keyword(s):  
Creatine Kinase ◽  
Rate Constant ◽  
Reaction Rate ◽  
Intermittent Exercise ◽  
Statistical Significance ◽  
Maximum Voluntary Contraction ◽  
Reaction Rate Constant ◽  
Flexor Digitorum Profundus ◽  
Resonance Spectroscopy ◽  
Pseudo First Order Reaction

Using31P magnetic resonance spectroscopy, creatine kinase (CK) reaction kinetics was assessed in the forearm flexor digitorum profundus muscle of healthy young ( n = 11, age 34.7 ± 5 yr) and older ( n = 20, age 73.5 ± 8 yr) subjects at rest, intermittent exercise at 20% maximum voluntary contraction (MVC), and 40% MVC. Exercise resulted in a significant increase in the average ratio of inorganic phosphate (Pi) to phosphocreatine (PCr) from resting values of 0.073 ± 0.031 (young) and 0.082 ± 0.037 (older) to 0.268 ± 0.140 (young, P < 0.01) and 0.452 ± 0.387 (older, P < 0.01) at 40% MVC. At 40% MVC, intracellular pH decreased significantly, from resting values of 7.08 ± 0.08 (young) and 7.08 ± 0.11 (older) to 6.84 ± 0.19 (young, P < 0.05) and to 6.75 ± 0.25 (older, P < 0.05). Average values of the pseudo-first-order reaction rate k (PCr→ATP) at rest were 0.07 ± 0.04 s−1 in the young and 0.07 ± 0.03 s−1 in the older group. At both exercise levels, the reaction rate constant increased compared with the resting value, but only the difference between the resting value and the 20% MVC value, which showed an 86% higher reaction rate constant in both groups, reached statistical significance ( P < 0.05). No difference in the reaction rate constant between the young and older groups was observed at either exercise level. As with k (PCr→ATP), the average phosphorus flux through the CK reaction increased during exercise at 20% MVC ( P < 0.05 in the older group) but decreased toward resting values at 40% MVC in both groups. The data in our study suggest that normal aging does not significantly affect the metabolic processes associated with the CK reaction.

Influence of Reduction Time of SSI on Nitrite Removal from Wastewater

2012 ◽  
Vol 450-451 ◽  
pp. 667-671 ◽  
Author(s):  
Jun Guo Li ◽  
Shou Zhang Li ◽  
Wei Tian
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Direct Reduction ◽  
Nitrate Removal ◽  
Reaction Rate Constant ◽  
Pseudo First Order Reaction ◽  
Reduction Time ◽  
Nitrite Removal ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology of SSI and its removal ability for nitrate from wastewater, the influence of reduction time of SSI on nitrate removal percentage was investigated. Because the specific surface area was impact smartly by the reduction time of SSI, it was suggested that nitrate removal ability of SSI should declined with the increasing of reduction time once the reduction time longer than the optimized reduction time. When the reduction time was t1, nitrate removal percentage reached to the maximum. When the nitrate original concentration was 5mg-N/L, the reaction order was closed to 0.7 and the apparent reaction rate constant was 0.323 to 0.359 h-1. When nitrate original concentration increased to 50 mg-N/L, nitrate removal reaction appeared to be the pseudo-first-order reaction, and the apparent reaction rate constant was 0.314 to 0.248 h-1.

Pyrolysis Modeling in a Woodstove

2008 ◽  
Author(s):  
Rajesh Gupta
Keyword(s):  
Rate Constant ◽  
Empirical Model ◽  
Reaction Rate ◽  
Packed Bed ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
Simple Empirical Model

A simple empirical model for predicting the pyrolysis rate of fuel packed bed of a woodstove has been presented. The thermolytic behavior of the fuel bed has been approximated by a pseudo-first order reaction. The reaction rate constant has been determined as function of temperature. The effect of orientation of twigs in the fuel bed arrangement and twig diameter on the reaction rate constant has been analyzed. It has been concluded that the effect of twig orientation is insignificant while the peak magnitude of reaction rate constant increased with increasing twig diameter.

scholarly journals Kinetics of heterogeneous methanolysis of sunflower oil with CaO∙ZnO catalyst: Influence of different hydrodynamic conditions

2014 ◽  
Vol 20 (3) ◽  
pp. 425-439 ◽  
Author(s):  
Ivana Lukic ◽  
Zeljka Kesic ◽  
Svetolik Maksimovic ◽  
Miodrag Zdujic ◽  
Jugoslav Krstic ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Rate Constant ◽  
Sunflower Oil ◽  
Reaction Rate ◽  
Catalyst Surface ◽  
Reaction Rate Constant ◽  
Molar Ratio ◽  
Model Parameters ◽  
Pseudo First Order Reaction ◽  
Kinetics Of

The kinetics of heterogeneous methanolysis of sunflower oil was studied at 60?C using mechanochemically synthesized CaO?ZnO as catalyst. Influence of agitation speed, catalyst amount and methanol to oil molar ratio on the rate of reaction was analyzed. The rate of the process depends on the two resistances - mass transfer of triglycerides to the catalyst surface and chemical reaction on the catalyst surface, which are defined as the values of the overall triglyceride volumetric mass transfer coefficient, kmt,TG, and the effective pseudo first-order reaction rate constant, k, respectively. These kinetic parameters actually determine the value of the apparent reaction rate constant, kapp, whose change with time is defined with the change of triglyceride (TG) conversion. The kinetic model was proposed and the model parameters determined.

Influence of Reduction Agent of SSI on its Cadmium Removal from Wastewater

2012 ◽  
Vol 251 ◽  
pp. 406-410
Author(s):  
Jun Guo Li ◽  
Yan Shi ◽  
Na Bi
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Direct Reduction ◽  
Reaction Rate Constant ◽  
Cadmium Removal ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by charcoal or hydrogen. The capability of cadmium removal by SSI was investigated in. It was suggested that the reaction of SSI reduced by hydrogen was higher than that reduced by charcoal, and the increasing rate of pH and cadmium removal in solution by SSI reduced by hydrogen was higher than that reduced by charcoal. Moreover, cadmium removal percentage by SSI reduced with hydrogen was much higher than that reduced by charcoal. When the original concentration of cadmium was 50mg/L, cadmium removal by SSI appeared to be the pseudo-first-order reaction because the reaction order was from 0.861 to 0.984. The apparent reaction rate constant of cadmium removal by SSI reduced with charcoal was 0.586 h-1. While hydrogen was utilized as reduction agent, the apparent reaction rate constant of cadmium removal was increased by 7.3 and 13.7 times.

scholarly journals Determination of exothermic batch reactor specific model parameters

2019 ◽  
Vol 292 ◽  
pp. 01063
Author(s):  
Lubomír Macků
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Specific Model ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Model Parameters ◽  
Reactor Model ◽  
First Order

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.

Performance of Photocatalytic Microfiltration with Hollow Fiber Membrane

2007 ◽  
Vol 544-545 ◽  
pp. 95-98 ◽  
Author(s):  
Jong Tae Jung ◽  
Jong Oh Kim ◽  
Won Youl Choi
Keyword(s):  
Heavy Metals ◽  
Humic Acid ◽  
Rate Constant ◽  
Hollow Fiber ◽  
Reaction Rate ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Reaction Rate Constant ◽  
Operational Parameters ◽  
Tio2 Particles

The purpose of this study is to investigate the effect of the operational parameters of the UV intensity and TiO2 dosage for the removal of humic acid and heavy metals. It also evaluated the applicability of hollow fiber microfiltration for the separation of TiO2 particles in photocatalytic microfiltration systems. TiO2 powder P-25 Degussa and hollow fiber microfiltration with a 0.4 μm nominal pore size were used for experiments. Under the conditions of pH 7 and a TiO2 dosage 0.3 g/L, the reaction rate constant (k) for humic acid and heavy metals increased with an increase of the UV intensity in each process. For the UV/TiO2/MF process, the reaction rate constant (k) for humic acid and Cu, with the exception of Cr in a low range of UV intensity, was higher compared to that of UV/TiO2 due to the adsorption of the membrane surface. The reaction rate constant (k) increased as the TiO2 dosage increased in the range of 0.1~0.3 g/L. However it decreased for a concentration over 0.3 g/L of TiO2. For the UV/TiO2/MF process, TiO2 particles could be effectively separated from treated water via membrane rejection. The average removal efficiency for humic acid and heavy metals during the operational time was over 90 %. Therefore, photocatalysis with a membrane is believed to be a viable process for humic acid and heavy metals removal.

Reaction rate constant of SO3+ NH3in the gas phase

1990 ◽  
Vol 95 (D9) ◽  
pp. 13981 ◽  
Author(s):  
Gaunlin Shen ◽  
Masako Suto ◽  
L. C. Lee
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant

Prediction of Chemical Reaction Yield in a Microreactor and Development of a Pilot Plant Using the Numbering-Up of Microreactors

2010 ◽  
Author(s):  
Shigenori Togashi ◽  
Yukako Asano ◽  
Yoshishige Endo
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Chemical Reaction ◽  
Rate Constant ◽  
Pilot Plant ◽  
Reaction Rate ◽  
Main Product ◽  
Reaction Rate Constant ◽  
Reaction Yield ◽  
Production Scale

The chemical reaction yield was predicted by using Monte Carlo simulation. The targeted chemical reaction of a performance evaluation using the microreactor is the consecutive reaction. The main product P1 is formed in the first stage with the reaction rate constant k1. Moreover, the byproduct P2 is formed in the second stage with the reaction rate constant k2. It was found that the yield of main product P1 was improved by using a microreactor when the ratio of the reaction rate constants became k1/k2 >1. To evaluate the Monte Carlo simulation result, the yields of the main products obtained in three consecutive reactions. It was found that the yield of the main product in cased of k1/k2 >1 increased when the microreactor was uesd. Next, a pilot plant involving the numbering-up of 20 microreactors was developed. The 20 microreactor units were stacked in four sets, each containing five microreactor units arranged. The maximum flow rate when 20 microreactors were used was 1 × 104 mm3/s, which corresponds to 72 t/year. Evaluation of the chemical performance of the pilot plant was conducted using a nitration reaction. The pilot plant was found to capable of increasing the production scale without decreasing the yield of the products.

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