Sporicidal Kinetics of Bacillus subtilis Spores by Heated Scallop Shell Powder

2003 ◽  
Vol 66 (8) ◽  
pp. 1482-1485 ◽  
Author(s):  
JUN SAWAI ◽  
HIROYUKI MIYOSHI ◽  
HIROMITSU KOJIMA
Keyword(s):  
Activation Energy ◽  
Bacillus Subtilis ◽  
Rate Constants ◽  
Death Rate ◽  
Inverse Relationship ◽  
Scallop Shell ◽  
Powder Concentration ◽  
Apparent Death ◽  
Kinetics Of ◽  
Shell Powder

Scallop shell powder heated at 1,000°C for 1 h exhibited sporicidal action against Bacillus subtilis spores. The sporicidal kinetics of this action were analyzed with the use of a nonlogarithmic model. Apparent death rate constants (k) were obtained under various conditions. The value of k increased with powder concentration but became constant beyond the concentration representing the solubility of Ca(OH)2. A linear inverse relationship between k and temperature was found, and from this relationship the activation energy required for the death of B. subtilis spores in the heated shell powder slurry could be determined.

scholarly journals The Kinetics of Peroxynitrite on Insulin Nitration Damage

2020 ◽  
Author(s):  
Congxiao Zhang ◽  
Fusheng Sun ◽  
Congjiang Zhang ◽  
Yunjing Luo
Keyword(s):  
Activation Energy ◽  
Biological Activity ◽  
Glucose Metabolism ◽  
Rate Constants ◽  
The Body ◽  
Stopped Flow ◽  
Tyrosine Nitration ◽  
Protein Nitration ◽  
Physiological Conditions ◽  
Kinetics Of

Abstract Background: Insulin is one of the most important versatile hormones that is central to regulating the energy and glucose metabolism in the body. There has been accumulating evidence supporting that diabetes was associated with peroxynitrite and protein nitration, and insulin nitration induced by peroxynitrite affected its biological activity. Methods: In this paper, the kinetics of insulin nitration by peroxynitrite in physiological conditions was studied by the stopped flow technique. Results: We determined the values of the reactive rate constants of peroxynitrite decomposition and peroxynitrite-induced tyrosine nitration in the presence of insulin. The activation energy of peroxynitrite decomposition and 3-nitrotyrosine yield in the presence of insulin is 48.8 kJ·mol−1 and 42.7 kJ·mol−1 respectively. Conclusions: It is inferred that the glutamate residue of insulin accelerated peroxynitrite decomposition and tyrosine nitration by reducing the activation energy of reactions. The results could be beneficial for exploring the molecular mechanism of diabetes and offering a new target for diabetes therapies.

Vulcanization of Elastomers. 40. Vulcanization of Natural Rubber and Synthetic Rubber with Sulfur in Presence of Sulfenamides. III

1965 ◽  
Vol 38 (1) ◽  
pp. 189-203 ◽  
Author(s):  
W. Scheele ◽  
J. Helberg
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
Rate Constants ◽  
Sulfur Concentration ◽  
Kcal Mole ◽  
Synthetic Rubber ◽  
Chemical Constitution ◽  
Induction Times ◽  
Kinetics Of

Abstract Vulcanization of natural rubber with sulfur was studied in presence of six sulfenamides, to determine the effect of the chemical constitution of the sulfenamide on sulfur decrease and on crosslinking. The results can be condensed as follows: (1) The kinetics of sulfur disappearance is in every respect qualitatively independent of the chemical constitution of the sulfenamide. (2) For the sulfenamides investigated, the smallest and largest rate constants for sulfur decrease differed only by a factor of two. (3) Greater differences are encountered in the induction times for sulfur decrease and for crosslinking. The latter are notably longer than those for sulfur disappearance. (4) The same activation energy, 23 kcal/mole, is derived from the temperature dependence of the induction times for all the sulfenamides. (5) The dissociation of sulfenamides in solution and their reaction with mercaptobenzothiazole were investigated further. The results provide the basis for a proposed reaction mechanism, which is presented in detail and can account for a number of the features typical of sulfenamide-accelerated vulcanization. (6) The drop in sulfur concentration goes at practically the same rate, if one introduces, instead of N, N-dicyclohexyl-2-benzothiazolesulfenamide, the corresponding ammonium mercaptide in equimolar concentration.

Kinetics of Zinc(II) Reduction at the Hg Electrode in WaterEthanol Mixtures

1994 ◽  
Vol 59 (7) ◽  
pp. 1545-1550 ◽  
Author(s):  
Barbara Marczewska
Keyword(s):  
Activation Energy ◽  
Charge Transfer ◽  
Rate Constants ◽  
Diffusion Coefficients ◽  
Transfer Rate ◽  
Electrode Process ◽  
Formal Potential ◽  
Charge Transfer Rate ◽  
Kinetics Of

The kinetics of the Zn(II)-Zn(Hg) electrode process was studied in water ethanol NaClO4 mixtures. Diffusion coefficients, formal potential and charge transfer rate constants were determined. The results are interpreted taking into account the change of the activation energy of the process.

Effect of CMCS on Vulcanization Kinetics of Natural Rubber

2012 ◽  
Vol 535-537 ◽  
pp. 1214-1217
Author(s):  
Yong Zhou Wang ◽  
Hong Xing Gui ◽  
Tao Chen ◽  
Hong Hai Huang ◽  
Fu Quan Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Natural Rubber ◽  
Induction Period ◽  
Rate Constants ◽  
Carboxymethyl Chitosan ◽  
Curing Period ◽  
Vulcanization Kinetics ◽  
Kinetics Of ◽  
Work Effect

In this work, effect of carboxymethyl chitosan (CMCS) on vulcanization kinetics of natural rubber was studied using the Rheometer MDR2000.The results showed that both the rate constants of induction period and curing period of natural rubber (K-N) was greater than that of natural rubber added CMCS and the dosage is 0.05% of fresh latex (CMCS-1), but less than that of natural rubber added CMCS and the dosage is 0.1% of fresh latex (CMCS-2), and the activation energy 100.8kJ/mol of induction period of K-N is greater than the activation energy 96.7kJ/mol, 93.7kJ/mol of induction period of CMCS-1, CMCS-2, respectively and that the activation energy 104.4 kJ/mol of curing period of K-N is less than the activation energy111.9kJ/mol of curing period of CMCS-1, and bigger than the activation energy 103.4 of CMCS-2 at the same temperature.

The sterilizing effect againstBacillus subtilisspores of hydrogen peroxide at different temperatures and concentrations

1968 ◽  
Vol 35 (3) ◽  
pp. 423-428 ◽  
Author(s):  
P. Swartling ◽  
B. Lindgren
Keyword(s):  
Hydrogen Peroxide ◽  
Bacillus Subtilis ◽  
Rate Constant ◽  
Rate Constants ◽  
Death Rate ◽  
Survival Curves ◽  
First Order ◽  
Commercial Practice ◽  
Different Temperatures ◽  
Experimental Findings

SummaryAn investigation was made of the death-rate ofBacillus subtilisspores in suspension in hydrogen peroxide concentrations of 10, 15 and 20% at 25, 50, 60, 70 and 80°C. Average logarithmic survival curves were plotted against normal time and death-rate constants andQ10values were calculated from the graphically determined decimal reduction times. This treatment of the experimental findings was found to be warranted in the temperature range 60–80°C. The first-order death-rate constant was ∽ 0·1 s−1for 10% hydrogen peroxide solution at 60°C and theQ10was about 1·6. Increases in the concentration from 10 to 15% and from 15 to 20% each gave an increase of about 50% in the rate constant. The application of these data to commercial practice is discussed.

Dissolution kinetics of sepiolite from Eskisehir (Turkey) in hydrochloric and nitric acids

Clay Minerals ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 207-215 ◽  
Author(s):  
H. Cetisli ◽  
T. Gedikbey
Keyword(s):  
Activation Energy ◽  
Acid Concentration ◽  
Rate Constants ◽  
Reaction Rate ◽  
Dissolution Kinetics ◽  
Particle Sizes ◽  
Initial Particle ◽  
Reaction Rate Constants ◽  
Apparent Activation Energies ◽  
Kinetics Of

AbstractDissolution kinetics of sepiolite from Eskisehir (Turkey) have been investigated at various temperatures and particle sizes using dilute hydrochloric and nitric acids. Dissolution reaction rate constants were calculated and apparent activation energies were dependent on acid concentration. For both acids, apparent activation energy values reached a minimum of ∼11 kcal/mol at an acid concentration of 0·75 M. For the second-order reaction which is independent of the acid concentration, the activation energy was 14·5 kcal/mol for both acids. The reaction rate constants were proportional to the acid concentrations, and inversely proportional to the square-root of the initial particle radii of the sepiolite.

The kinetics of dehydroxylation of kaolinite

Clay Minerals ◽  
1987 ◽  
Vol 22 (4) ◽  
pp. 447-456 ◽  
Author(s):  
S. A. T. Redfern
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Kinetic Analysis ◽  
Rate Constants ◽  
Avrami Equation ◽  
Isothermal Thermogravimetry ◽  
Temperature Range ◽  
Homogeneous Models ◽  
Kinetics Of ◽  
Fraction Method

AbstractThe dehydroxylation of kaolinite has been investigated by isothermal thermogravimetry. Kinetic analysis using the Avrami equation shows that a combination of atomic mechanisms operates throughout the temperature range 734 K to 890 K. An empirical activation energy of 222 kJ mol-1 was calculated from the Arrhenius relationship using rate constants based on diffusion and homogeneous models. The activation energy (Ea) was calculated for a series of degrees of dehydroxylation by the time to a given fraction method, showing an increase in Ea during the early stages of the reaction. The isothermal plots indicate that OH is retained in the final stages of the reaction. The observations are explained in terms of a reaction mechanism in which kaolinite grains dehydroxylate from the edges inwards, parallel to (001).

Vulcanization Kinetics of Natural Rubber Coagulated by Microorganisms with Use of a Vulcameter

2010 ◽  
Vol 160-162 ◽  
pp. 1181-1186 ◽  
Author(s):  
Zhi Feng Wang ◽  
Si Dong Li ◽  
Xiao Dong She
Keyword(s):  
Activation Energy ◽  
Natural Rubber ◽  
Rate Constants ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Second Stage ◽  
End Stage ◽  
Two Stages ◽  
Kinetics Of

Kinetics of vulcanization of natural rubber coagulated by microorganisms (NR-m) was studied with the use of a vulcameter. In the induction period of vulcanization, the time t0 of NR-m is shorter than that of natural rubber coagulated by acid (NR-a), and the rate constant k1/a of NR-m are greater than that of NR-a. Both the curing periods of NR-m and NR-a consist of two stages. The first stage follows first-order reaction. The rate constants k2 of NR-m in the first stage are greater than that of NR-a at the same temperature, and so are the activation energy E2. The second stage (end stage of the curing period) does not follow first-order reaction, and the calculated reaction order n of NR-m is in the range of 0.82-0.85, and that of NR-a is in the range of 0.64-0.72. The rate constants k3 of the second stage for NR -m are greater than that of NR-a at the same temperature, and so is the activation energy E3.

scholarly journals Examination of the kinetics of Zr1.02Ni0.98 alloy hydriding

1999 ◽  
Vol 64 (12) ◽  
pp. 745-752 ◽  
Author(s):  
Branislav Simonovic ◽  
Slavko Mentus ◽  
Milenko Susic
Keyword(s):  
Activation Energy ◽  
Surface Area ◽  
Rate Constant ◽  
Rate Constants ◽  
Alloy Sample ◽  
Kinetics Of ◽  
Hydriding Kinetics

The hydriding kinetics of Zr1.02Ni0.98 alloy was examined in dependence on the number of hydriding/dehydriding cycles. The rate constants relating to three subsequent hydriding procedures of an alloy sample, at five temperatures: 423, 448, 473, 498 and 523K, were determined. The rate constant increases, and the activation energy decreases on each repetition of the hydriding/dehydriding cycle at a given temperature. This behavior was explained by sample crushing, leading to an increase in the surface area accessible to hydrogen.

Depolymerization Kinetics of Glass-Forming Chalcogenide Melts. Coherence TYansfer NMR Studies of Phosphorus Selenide

1995 ◽  
Vol 50 (4-5) ◽  
pp. 395-404 ◽  
Author(s):  
Robert Maxwell ◽  
Hans Erickson ◽  
Hellmut Eckert
Keyword(s):  
Activation Energy ◽  
Rate Constants ◽  
Spectroscopic Methods ◽  
Two Dimensional ◽  
Coherence Transfer ◽  
Temperature Dependent ◽  
Nmr Studies ◽  
One Dimensional ◽  
Glass Forming ◽  
Kinetics Of

Abstract The kinetics of the depolymerization of a glass-forming phosphorus selenide melt containing 48 at.% phosphorus have been studied using one- and two-dimensional coherence transfer spectroscopic methods. The depolymerization leads to the creation of molecular P4Se3. Two-dimensional spectroscopy indicates that these units are in slow exchange with the residual polymeric matrix, and corresponding rate constants are extracted from temperature dependent one-dimensional coherence transfer experiments. The results are quantitatively consistent with previous temperature-dependent NMR lineshape studies, yielding an activation energy of 109 kJ/mol

Sign in / Sign up

Export Citation Format

Share Document