Role of State Specificity in the Temperature- and Pressure-Dependent Unimolecular Rate Constants for HO2→ H + O2Dissociation

1998 ◽  
Vol 102 (8) ◽  
pp. 1292-1296 ◽  
Author(s):  
Kihyung Song ◽  
William L. Hase
Keyword(s):  
Rate Constants ◽  
Temperature And Pressure

scholarly journals The Role of H2C2O4 and Na2CO3 as Precipitating Agents on The Physichochemical Properties and Photocatalytic Activity of Bismuth Oxide

2020 ◽  
Vol 18 (1) ◽  
pp. 129-137
Author(s):  
Yayuk Astuti ◽  
Rizka Andianingrum ◽  
Abdul Haris ◽  
Adi Darmawan ◽  
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Physicochemical Properties ◽  
Bismuth Oxide ◽  
Rate Constants ◽  
Degradation Rate ◽  
Precipitation Method ◽  
Methyl Orange Degradation ◽  
Methyl Orange Dye

AbstractSynthesis of bismuth oxide synthesis through the precipitation method using H2C2O4 and Na2CO3 precipitating agents, identification of physicochemical properties and its photocatalysis activity for methyl orange degradation were conducted. The bismuth oxide synthesis was undertaken by dissolving Bi(NO3)3.5H2O in HNO3, then added precipitating agents to form precipitate. The results showed that bismuth oxide produced by H2C2O4 precipitating agent was a yellow powder containing a mixture of α-Bi2O3 (monoclinic) and β-Bi2O3 (tetragonal), porous with size of 28-85 μm. Meanwhile, the use of Na2CO3 as precipitating agent resulted in bismuth oxide consisting of α-Bi2O3 and β-Bi2O3 and Bi2O4, irregular shape without pore being 40-115 μm in size. Bismuth oxide synthesized with H2C2O4 precipitating agent showed higher photocatalytic activity compared to bismuth oxide synthesized using Na2CO3 on degrading methyl orange dye with degradation rate constants of 2.35x10-5 s-1 for H2C2O4 and 1.81x10-5 s-1 for Na2CO3.

scholarly journals Deciphering the role of quantum dot size in the ultrafast charge carrier dynamics at the perovskite–quantum dot interface

2020 ◽  
Vol 8 (42) ◽  
pp. 14834-14844
Author(s):  
Piotr Piatkowski ◽  
Sofia Masi ◽  
Pavel Galar ◽  
Mario Gutiérrez ◽  
Thi Tuyen Ngo ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Charge Carrier ◽  
Rate Constants ◽  
Transient Absorption ◽  
Carrier Dynamics ◽  
Carrier Transfer ◽  
Charge Carrier Dynamics ◽  
Conduction Bands

Charge-carrier transfer (CT) from the perovskite host to PbS QDs were studied using fs-transient absorption and THz techniques. The CT rate constants increase with the size of QDs due to a change in the position of valence and conduction bands in PbS QDs.

scholarly journals Phosphate has dual roles in cross-bridge kinetics in rabbit psoas single myofibrils

2021 ◽  
Vol 153 (3) ◽  
Author(s):  
Masataka Kawai ◽  
Robert Stehle ◽  
Gabriele Pfitzer ◽  
Bogdan Iorga
Keyword(s):  
Rate Constants ◽  
Striated Muscle ◽  
Intrinsic Rate ◽  
Isometric Tension ◽  
Force Generation ◽  
Skinned Fibers ◽  
Sinusoidal Analysis ◽  
Rabbit Psoas ◽  
Cross Bridge

In this study, we aimed to study the role of inorganic phosphate (Pi) in the production of oscillatory work and cross-bridge (CB) kinetics of striated muscle. We applied small-amplitude sinusoidal length oscillations to rabbit psoas single myofibrils and muscle fibers, and the resulting force responses were analyzed during maximal Ca2+ activation (pCa 4.65) at 15°C. Three exponential processes, A, B, and C, were identified from the tension transients, which were studied as functions of Pi concentration ([Pi]). In myofibrils, we found that process C, corresponding to phase 2 of step analysis during isometric contraction, is almost a perfect single exponential function compared with skinned fibers, which exhibit distributed rate constants, as described previously. The [Pi] dependence of the apparent rate constants 2πb and 2πc, and that of isometric tension, was studied to characterize the force generation and Pi release steps in the CB cycle, as well as the inhibitory effect of Pi. In contrast to skinned fibers, Pi does not accumulate in the core of myofibrils, allowing sinusoidal analysis to be performed nearly at [Pi] = 0. Process B disappeared as [Pi] approached 0 mM in myofibrils, indicating the significance of the role of Pi rebinding to CBs in the production of oscillatory work (process B). Our results also suggest that Pi competitively inhibits ATP binding to CBs, with an inhibitory dissociation constant of ∼2.6 mM. Finally, we found that the sinusoidal waveform of tension is mostly distorted by second harmonics and that this distortion is closely correlated with production of oscillatory work, indicating that the mechanism of generating force is intrinsically nonlinear. A nonlinear force generation mechanism suggests that the length-dependent intrinsic rate constant is asymmetric upon stretch and release and that there may be a ratchet mechanism involved in the CB cycle.

Role of Temperature and Pressure on the Multisensitive Multiferroic Dicyanamide Framework [TPrA][Mn(dca)3] with Perovskite-like Structure

2015 ◽  
Vol 54 (24) ◽  
pp. 11680-11687 ◽  
Author(s):  
Juan M. Bermúdez-García ◽  
Manuel Sánchez-Andújar ◽  
Susana Yáñez-Vilar ◽  
Socorro Castro-García ◽  
Ramón Artiaga ◽  
...  
Keyword(s):  
Temperature And Pressure

Kinetic serum creatinine assays I. The role of various factors in determining specificity.

1980 ◽  
Vol 26 (5) ◽  
pp. 551-554
Author(s):  
L D Bowers
Keyword(s):  
Serum Creatinine ◽  
Rate Constants ◽  
Kinetic Methods ◽  
Relative Value ◽  
Keto Acids ◽  
Measuring Techniques ◽  
Main Factors ◽  
Analytical Reagent ◽  
Kinetic Methods Of Analysis

Abstract We studied the specificity of kinetic methods of analysis, with emphasis on creatinine determination. The error contributed by an interferent that reacts with the analytical reagent and absorbs at the wavelength of analysis is shown to be related to the ratio of the equilibrium absorbances of the analyte and interferent, the ratio of the rate constants, the extent of the analytical reaction, and the duration of the measurement. To assess the potential diminution of the interference with kinetic methods, we determined the rate constants of several alpha-keto acids in the Jaffé reaction. Evaluation of the advantages of various measuring techniques with respect to specificity showed the main factors to be the extent of the analytical reaction and the relative value of the rate constants. Total specificity for creatine appears to be unattainable with currently used kinetic techniques.

3. Minerals and the interior of the Earth

2014 ◽  
Author(s):  
David Vaughan
Keyword(s):  
Upper Mantle ◽  
Lower Mantle ◽  
Plate Tectonics ◽  
Inner Core ◽  
Indirect Evidence ◽  
Outer Core ◽  
The Earth ◽  
Granite Formation ◽  
Temperature And Pressure

‘Minerals and the interior of the Earth’ looks at the role of minerals in plate tectonics during the processes of crystallization and melting. The size and range of minerals formed are dependent on the temperature and pressure of the magma during its movement through the crust. The evolution of the continental crust also involves granite formation and processes of metamorphism. Our understanding of the interior of the Earth is based on indirect evidence, mainly the study of earthquake waves. The Earth consists of concentric shells: a solid inner core; liquid outer core; a solid mantle divided into a lower mantle, a transition zone, and an upper mantle; and then the outer rigid lithosphere.

The Role of Phenylalanine 31 in Maintaining the Conformational Stability of Ribonuclease P2 fromSulfolobus solfataricusunder Extreme Conditions of Temperature and Pressure†

Biochemistry ◽  
1997 ◽  
Vol 36 (29) ◽  
pp. 8733-8742 ◽  
Author(s):  
Enrico Mombelli ◽  
Mohammad Afshar ◽  
Paola Fusi ◽  
Margherita Mariani ◽  
Paolo Tortora ◽  
...  
Keyword(s):  
Conformational Stability ◽  
Extreme Conditions ◽  
Temperature And Pressure

Rate constants and first-principles trajectories for attack at tetrahedral carbon: Role of molecular orientation on chiral selectivity

2019 ◽  
Author(s):  
Marcos Vinícius C. S. Rezende ◽  
Priscila Gomes dos Santos ◽  
Nayara D. Coutinho ◽  
Federico Palazzetti ◽  
Andrea Lombardi ◽  
...  
Keyword(s):  
Rate Constants ◽  
First Principles ◽  
Molecular Orientation ◽  
Chiral Selectivity

Role of surfactants on metal mediated cerium(IV) oxidation of valeraldehyde at room temperature and pressure

2015 ◽  
Vol 211 ◽  
pp. 48-62 ◽  
Author(s):  
Aniruddha Ghosh ◽  
Pintu Sar ◽  
Susanta Malik ◽  
Bidyut Saha
Keyword(s):  
Room Temperature ◽  
Temperature And Pressure
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