A twin assemblies benchmark for coupling behavior and kinetics parameters calculations

Indole-3-acetic acid is a growth phytohormone considered the most important representative of auxin class. This paper presents the assessment of some kinetic parameters in the process of transport of indole-3-acetic acid taking into consideration the kinetic model of consecutive irreversible first order reactions. It was pursued the influence upon the process of parameters such as: feed phase concentration, stripping phase concentration in the presence of two type carriers: tributyl phosphate (TBP) and trioctylphosphine oxide (TOPO). Depending on these transport parameters were calculated kinetics parameters such as: pseudo-first-order apparent membrane entrance and exit rate constants, the maximum flux at the entrance and exit out of the membrane. The highest values of the transport flux is obtained in the presence of carrier trioctylphosphine oxide (TOPO) at the concentration in the feed phase of 10-4 mol/L indole-3-acetic acid and a concentration of 10--2mol/L NaOH in the stripping phase.

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Metabolic Analysis of Triptolide Microspheres in Human, Dog, Rabbit and Rat Liver Microsomes with UPLC-MS/MS Method

Current Pharmaceutical Analysis ◽

10.2174/1573412917999200909143213 ◽

2020 ◽

Vol 17 ◽

Author(s):

LiJuan Wang ◽

Yan Liu ◽

Rui Li ◽

DongXian He

Keyword(s):

Rat Liver ◽

Liver Microsomes ◽

Internal Standard ◽

Gradient Elution ◽

Rat Liver Microsomes ◽

Good Precision ◽

Kinetics Parameters ◽

Measure Concentration ◽

Standard Curve ◽

Variation Of Parameters

Objectives: Triptolide (TPL) has been shown to have a good clinical effect on rheumatoid arthritis (RA). We designed TPL microspheres (TPL-MS) and investigated its metabolic behavior in human, dog, rabbit and rat liver microsomes (HLM, DLM, RLM and SDRLM) with UPLC-MS/MS method. Methods: First, a UPLC-MS/MS method was established to measure concentration of TPL in samples. The sample was separated on a C18 column (2.1×100 mm, 1.8μm) and eluted with a gradient elution. The precursor ion/product ion were m/z 378.1/361.0 for TPL and 260.0/116.2 for the internal standard. Then T1/2, Vmax and CLint were calculated from the above data. Finally, the metabolites of TPL-MS were identified by high-resolution UPLC-MS/MS. The sample was separated on a C18 column (2.1×100 mm, 2.2 μm) and eluted with isocratic elution. Mass spectrometric detection was carried out on a thermo Q-exactive mass spectrometer with HESI. The scanning range of precursor ions was from m/z 50 to m/z 750. Result and Discussion: Through several indicators including standard curve, precision, accuracy, stability, matrix effect and recovery rate, the enzymatic kinetics parameters including T1/2, Vmax and CLint were completed. Several metabolites of TPL-MS were identified. Conclusion: UPLC-MS/MS method is an accurate and sensitive method for determination of TPL in liver microsome samples with good precision, accuracy and stability. The variation of parameters indicated that the microspheres can delay the elimination of TPL in liver microsomes. The metabolism of TPL-MS varied among species, but no new metabolites appeared.

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Validation of Pin-Resolved Reaction Rates, Kinetics Parameters, and Linear Source MOC in MPACT

Nuclear Science and Engineering ◽

10.1080/00295639.2020.1780853 ◽

2020 ◽

Vol 195 (1) ◽

pp. 50-68

Author(s):

Yuxuan Liu ◽

Kyle Vaughn ◽

Brendan Kochunas ◽

Thomas Downar

Keyword(s):

Reaction Rates ◽

Linear Source ◽

Kinetics Parameters

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Analytical Expressions for the Mixed-Order Kinetics Parameters of TL Glow Peaks Based on the two Heating Rates Method

Journal of Fluorescence ◽

10.1007/s10895-018-2222-7 ◽

2018 ◽

Vol 28 (2) ◽

pp. 597-603 ◽

Cited By ~ 1

Author(s):

Mufeed Maghrabi ◽

Tariq Al-Abdullah ◽

Ziad Khattari

Keyword(s):

Heating Rates ◽

Kinetics Parameters ◽

Mixed Order ◽

Analytical Expressions

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Comparative Analysis of Gas–Solid–Liquid Coupling Behavior in Front of the Working Face Before and After Water Injection During Coal Mining

Natural Resources Research ◽

10.1007/s11053-021-09816-6 ◽

2021 ◽

Author(s):

Yuexia Chen ◽

Tingxiang Chu ◽

Xuexi Chen ◽

Peng Chen

Keyword(s):

Comparative Analysis ◽

Coal Mining ◽

Water Injection ◽

Working Face ◽

Coupling Behavior ◽

Before And After ◽

Solid Liquid

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Effects of Camu-Camu (Myrciaria dubia) Powder on the Physicochemical and Kinetic Parameters of Deteriorating Microorganisms and Salmonella enterica Subsp. enterica Serovar Typhimurium in Refrigerated Vacuum-Packed Ground Beef

Agriculture ◽

10.3390/agriculture11030252 ◽

2021 ◽

Vol 11 (3) ◽

pp. 252

Author(s):

Jorge Luiz da Silva ◽

Vasco Cadavez ◽

José M. Lorenzo ◽

Eduardo Eustáquio de Souza Figueiredo ◽

Ursula Gonzales-Barron

Keyword(s):

Ground Beef ◽

Treated Group ◽

B Value ◽

Kinetics Parameters ◽

Psychrotrophic Bacteria ◽

Color Changes ◽

A Value ◽

Spoilage Bacteria ◽

Serovar Typhimurium ◽

And Control

This study aims to evaluate the effects of camu-camu powder (CCP), Amazonian berry fruit with documented bioactive properties, physicochemical meat parameters, and the growth kinetics parameters of S. enterica ser. Typhimurium, psychrotrophic bacteria (PSY), and lactic acid bacteria (LAB) in vacuum-packed ground beef. Batches of ground beef were mixed with 0.0%, 2.0%, 3.5%, and 5.0% CCP (w/w), vacuum-packed as 10 g portions, and stored at 5 °C for 16 days. Centesimal composition analyses (only on the initial day), pH, TBARS, and color were quantified on storage days 1, 7, and 15, while PSY and LAB were counted on days 0, 3, 6, 9, 13, and 16. Another experiment was conducted with the same camu-camu doses by inoculating S. enterica ser. Typhimurium microbial kinetic curves were modeled by the Huang growth and Weibull decay models. CCP decreased TBARS in beef from 0.477 to 0.189 mg MDA·kg−1. No significant differences in meat pH between treated and control samples were observed on day 15. CCP addition caused color changes, with color a* value decreases (from 14.45 to 13.44) and color b* value increases (from 17.41 to 21.25), while color L* was not affected. Higher CCP doses caused progressive LAB growth inhibition from 0.596 to 0.349 log CFU·day−1 at 2.0% and 5.0% CCP, respectively. Similarly, PSY growth rates in the treated group were lower (0.79–0.91 log CFU·day−1) compared to the control (1.21 log CFU·day−1). CCP addition at any of the investigated doses produced a steeper S. enterica ser. Typhimurium inactivation during the first cold storage day, represented by Weibull’s concavity α shape parameter, ranged from 0.37 to 0.51, in contrast to 1.24 for the control. At the end of the experiment, however, S. enterica ser. Typhimurium counts in beef containing CCP were not significantly different (p < 0.05) from the control. Although CCP affects bacterial kinetics, it does not protect ground beef against spoilage bacteria and Salmonella to the same degree it does against lipid peroxidation.

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Confinement, partial sleep deprivation and defined physical activity–influence on cardiorespiratory regulation and capacity

European Journal of Applied Physiology ◽

10.1007/s00421-021-04719-z ◽

2021 ◽

Author(s):

Jessica Koschate ◽

Uwe Drescher ◽

Uwe Hoffmann

Keyword(s):

Physical Activity ◽

Cardiorespiratory Fitness ◽

Space Mission ◽

Cycle Ergometer ◽

Work Rate ◽

Binary Sequences ◽

Kinetics Parameters ◽

Slow Heart Rate ◽

Partial Sleep Deprivation ◽

Sleep Schedule

Abstract Introduction Adequate cardiorespiratory fitness is of utmost importance during spaceflight and should be assessable via moderate work rate intensities, e.g., using kinetics parameters. The combination of restricted sleep, and defined physical exercise during a 45-day simulated space mission is expected to slow heart rate (HR) kinetics without changes in oxygen uptake ($${\dot{\text{V}}\text{O}}_{{2}}$$ V ˙ O 2 ) kinetics. Methods Overall, 14 crew members (9 males, 5 females, 37 ± 7 yrs, 23.4 ± 3.5 kg m−2) simulated a 45-d-mission to an asteroid. During the mission, the sleep schedule included 5 nights of 5 h and 2 nights of 8 h sleep. The crew members were tested on a cycle ergometer, using pseudo-random binary sequences, changing between 30 and 80 W on day 8 before (MD-8), day 22 (MD22) and 42 (MD42) after the beginning and day 4 (MD + 4) following the end of the mission. Kinetics information was assessed using the maxima of cross-correlation functions (CCFmax). Higher CCFmax indicates faster responses. Results CCFmax(HR) was significantly (p = 0.008) slower at MD-8 (0.30 ± 0.06) compared with MD22 (0.36 ± 0.06), MD42 (0.38 ± 0.06) and MD + 4 (0.35 ± 0.06). Mean HR values during the different work rate steps were higher at MD-8 and MD + 4 compared to MD22 and MD42 (p < 0.001). Discussion The physical training during the mission accelerated HR kinetics, but had no impact on mean HR values post mission. Thus, HR kinetics seem to be sensitive to changes in cardiorespiratory fitness and may be a valuable parameter to monitor fitness. Kinetics and capacities adapt independently in response to confinement in combination with defined physical activity and sleep.

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