Kinetics of digestive enzyme stability in the solid state. II. Quantitative prediction of enzyme inactivation.

1981 ◽  
Vol 29 (7) ◽  
pp. 2096-2100 ◽  
Author(s):  
MAMORU SUGIURA ◽  
MASAYUKI KUROBE ◽  
SUMIHIRO TAMURA ◽  
SHINICHI IKEDA
Keyword(s):  
Solid State ◽  
Enzyme Stability ◽  
Digestive Enzyme ◽  
Enzyme Inactivation ◽  
Quantitative Prediction ◽  
Kinetics Of

scholarly journals Investigation by Synchrotron Radiation Circular Dichroism of the Secondary Structure Evolution of Pepsin under Oxidative Environment

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 998
Author(s):  
Laetitia Théron ◽  
Aline Bonifacie ◽  
Jérémy Delabre ◽  
Thierry Sayd ◽  
Laurent Aubry ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Secondary Structure ◽  
Proteolytic Activity ◽  
Digestive Enzyme ◽  
Structure Evolution ◽  
Food Protein ◽  
Maldi Tof ◽  
Kinetics Of ◽  
Circular Dichroïsm

Food processing affects the structure and chemical state of proteins. In particular, protein oxidation occurs and may impair protein properties. These chemical reactions initiated during processing can develop during digestion. Indeed, the physicochemical conditions of the stomach (oxygen pressure, low pH) favor oxidation. In that respect, digestive proteases may be affected as well. Yet, very little is known about the link between endogenous oxidation of digestive enzymes, their potential denaturation, and, therefore, food protein digestibility. Thus, the objective of this study is to understand how oxidative chemical processes will impact the pepsin secondary structure and its hydrolytic activity. The folding and unfolding kinetics of pepsin under oxidative conditions was determined using Synchrotron Radiation Circular Dichroism. SRCD gave us the possibility to monitor the rapid kinetics of protein folding and unfolding in real-time, giving highly resolved spectral data. The proteolytic activity of control and oxidized pepsin was investigated by MALDI-TOF mass spectrometry on a meat protein model, the creatine kinase. MALDI-TOF MS allowed a rapid evaluation of the proteolytic activity through peptide fingerprint. This study opens up new perspectives by shifting the digestion paradigm taking into account the gastric digestive enzyme and its substrate.

scholarly journals Solid-State Redox Kinetics of CeO2 in Two-Step Solar CH4 Partial Oxidation and Thermochemical CO2 Conversion

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 723
Author(s):  
Mahesh Muraleedharan Nair ◽  
Stéphane Abanades
Keyword(s):  
Solid State ◽  
Solar Energy ◽  
Kinetic Models ◽  
Oxygen Carrier ◽  
Co2 Conversion ◽  
Oxidation Reactions ◽  
Redox Kinetics ◽  
Concentrated Solar Energy ◽  
Ceria Reduction ◽  
Kinetics Of

The CeO2/CeO2−δ redox system occupies a unique position as an oxygen carrier in chemical looping processes for producing solar fuels, using concentrated solar energy. The two-step thermochemical ceria-based cycle for the production of synthesis gas from methane and solar energy, followed by CO2 splitting, was considered in this work. This topic concerns one of the emerging and most promising processes for the recycling and valorization of anthropogenic greenhouse gas emissions. The development of redox-active catalysts with enhanced efficiency for solar thermochemical fuel production and CO2 conversion is a highly demanding and challenging topic. The determination of redox reaction kinetics is crucial for process design and optimization. In this study, the solid-state redox kinetics of CeO2 in the two-step process with CH4 as the reducing agent and CO2 as the oxidizing agent was investigated in an original prototype solar thermogravimetric reactor equipped with a parabolic dish solar concentrator. In particular, the ceria reduction and re-oxidation reactions were carried out under isothermal conditions. Several solid-state kinetic models based on reaction order, nucleation, shrinking core, and diffusion were utilized for deducing the reaction mechanisms. It was observed that both ceria reduction with CH4 and re-oxidation with CO2 were best represented by a 2D nucleation and nuclei growth model under the applied conditions. The kinetic models exhibiting the best agreement with the experimental reaction data were used to estimate the kinetic parameters. The values of apparent activation energies (~80 kJ·mol−1 for reduction and ~10 kJ·mol−1 for re-oxidation) and pre-exponential factors (~2–9 s−1 for reduction and ~123–253 s−1 for re-oxidation) were obtained from the Arrhenius plots.

scholarly journals Solid-State Lithium Battery Cycle Life Prediction Using Machine Learning

2021 ◽  
Vol 11 (10) ◽  
pp. 4671
Author(s):  
Danpeng Cheng ◽  
Wuxin Sha ◽  
Linna Wang ◽  
Shun Tang ◽  
Aijun Ma ◽  
...  
Keyword(s):  
Machine Learning ◽  
Solid State ◽  
Life Prediction ◽  
Learning Algorithm ◽  
Remaining Useful Life ◽  
Cycle Life ◽  
Quantitative Prediction ◽  
Test Accuracy ◽  
Machine Learning Algorithm ◽  
Discharge Data

Battery lifetime prediction is a promising direction for the development of next-generation smart energy storage systems. However, complicated degradation mechanisms, different assembly processes, and various operation conditions of the batteries bring tremendous challenges to battery life prediction. In this work, charge/discharge data of 12 solid-state lithium polymer batteries were collected with cycle lives ranging from 71 to 213 cycles. The remaining useful life of these batteries was predicted by using a machine learning algorithm, called symbolic regression. After populations of breed, mutation, and evolution training, the test accuracy of the quantitative prediction of cycle life reached 87.9%. This study shows the great prospect of a data-driven machine learning algorithm in the prediction of solid-state battery lifetimes, and it provides a new approach for the batch classification, echelon utilization, and recycling of batteries.

Effect of praseodymium on the solid-state oxidation kinetics of an AMg2 alloy

2015 ◽  
Vol 2015 (7) ◽  
pp. 521-524 ◽  
Author(s):  
N. F. Ibrokhimov ◽  
I. N. Ganiev ◽  
A. E. Berdiev ◽  
N. I. Ganieva
Keyword(s):  
Solid State ◽  
Oxidation Kinetics ◽  
Kinetics Of
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