Methods for kinetic analysis of simultaneous, first-order reactions in waters: The kinetic model and methods for data analysis

1994 ◽  
Vol 288 (3) ◽  
pp. 131-139 ◽  
Author(s):  
Yanjia Lu ◽  
C.L. Chakrabarti ◽  
M.H. Back ◽  
D.C. Grégoire ◽  
W.H. Schroeder ◽  
...  
2020 ◽  
Vol 61 (10) ◽  
pp. 1940-1948
Author(s):  
Vothy Hornn ◽  
Mayumi Ito ◽  
Ryosuke Yamazawa ◽  
Hiromasa Shimada ◽  
Carlito Baltazar Tabelin ◽  
...  

Author(s):  
Manoj Kumar ◽  
Rajesh Singh

In the present study area-based, pollutant removal kinetic analysis was considered using the Zero-order, first-order decay and efficiency loss (EL) models in the constructed wetlands (CWs) for municipal wastewater treatment....


Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1633-1648 ◽  
Author(s):  
Adam Arkin ◽  
John Ross ◽  
Harley H McAdams

Abstract Fluctuations in rates of gene expression can produce highly erratic time patterns of protein production in individual cells and wide diversity in instantaneous protein concentrations across cell populations. When two independently produced regulatory proteins acting at low cellular concentrations competitively control a switch point in a pathway, stochastic variations in their concentrations can produce probabilistic pathway selection, so that an initially homogeneous cell population partitions into distinct phenotypic subpopulations. Many pathogenic organisms, for example, use this mechanism to randomly switch surface features to evade host responses. This coupling between molecular-level fluctuations and macroscopic phenotype selection is analyzed using the phage λ lysis-lysogeny decision circuit as a model system. The fraction of infected cells selecting the lysogenic pathway at different phage:cell ratios, predicted using a molecular-level stochastic kinetic model of the genetic regulatory circuit, is consistent with experimental observations. The kinetic model of the decision circuit uses the stochastic formulation of chemical kinetics, stochastic mechanisms of gene expression, and a statistical-thermodynamic model of promoter regulation. Conventional deterministic kinetics cannot be used to predict statistics of regulatory systems that produce probabilistic outcomes. Rather, a stochastic kinetic analysis must be used to predict statistics of regulatory outcomes for such stochastically regulated systems.


2010 ◽  
Vol 5 (12) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Paul Slusarewicz ◽  
Keng Zhu ◽  
Tom Hedman

Degradation of genipin (GP), a low toxicity natural protein crosslinking agent, in aqueous solution was monitored by HPLC at various pH levels. Degradation of GP was consistent with a mechanism consisting of a first order reaction with a reversible first step. Formation of the intermediate was slowest at more neutral pHs while formation of the irreversible product was correlated to increasing alkalinity. Degradation at all pHs was enhanced by the presence of phosphate ions. Degradation of GP most likely proceeds via the reversible opening of the dihydropyran ring by water followed by irreversible polymerization of the intermediate. Degraded solutions containing no detectable GP or intermediate, however, are still capable of crosslinking proteins.


Proceedings ◽  
2019 ◽  
Vol 42 (1) ◽  
pp. 9
Author(s):  
Gianfranco Carotenuto ◽  
Carlo Camerlingo

Wearable electrical sensors based on zeolites can be used for breath monitoring. The high silicon content of clinoptilolite makes this type of zeolite very adequate for fabricating sensitive water sensors. In addition to sensitivity, response fastness also represents a sensor characteristic of fundamental importance for breath monitoring. Here, the response fastness of a clinoptilolite-based water sensor has been evaluated by measuring the current intensity behavior upon exposition to a constant humidity atmosphere (75%). In particular, the clinoptilolite surface has been biased with a sinusoidal signal (20 Vpp, 5 kHz), and the true-RMS current intensity value has been recorded during exposition to the constant humidity atmosphere. Since current intensity is proportional to the adsorbed water concentration (only hydrated cations are charge carriers) a kinetic analysis has been possible. The clinoptilolite dehydration kinetics in a dry atmosphere have been evaluated too. According to this kinetic analysis, water adsorption is described by a Lagergren pseudo-first-order model with a rate constant of (58.6 ± 0.9)·10−4 min−1, while desorption in dry air follows a first-order kinetic model with a specific rate of (202.7 ± 0.3)·10−4 min−1 at 25 °C.


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