Automated fast reaction-rate system for phosphate determinations in the millisecond range

1969 ◽  
Vol 41 (2) ◽  
pp. 239-243 ◽  
Author(s):  
Adelina C. Javier ◽  
S. R. Crouch ◽  
Howard V. Malmstadt
Keyword(s):  
Reaction Rate ◽  
Fast Reaction ◽  
Rate System ◽  
Millisecond Range ◽  
Fast Reaction Rate

Non-classical hydrogen bond triggered strand displacement for analytical applications and DNA nanostructure assembly

2018 ◽  
Vol 42 (9) ◽  
pp. 6636-6639 ◽  
Author(s):  
Manli Han ◽  
Qingsheng Fan ◽  
Yi Zhang ◽  
Lida Xu ◽  
Changyuan Yu ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Reaction Rate ◽  
Cyanuric Acid ◽  
Strand Displacement ◽  
Fast Reaction ◽  
Dna Nanostructure ◽  
Analytical Applications ◽  
Classical Hydrogen Bond ◽  
Fast Reaction Rate

A novel strand displacement triggered by the non-classical hydrogen bond between cyanuric acid and adenine exhibits a fast reaction rate.

A Study Numerical Simulation of Post Combustion CO2 Capture Process

2009 ◽  
Author(s):  
Rosa-Hilda Chavez ◽  
Javier de J. Guadarrama ◽  
Abel Hernandez-Guerrero
Keyword(s):  
Co2 Capture ◽  
Flue Gas ◽  
Reaction Rate ◽  
Operating Cost ◽  
Chemical Processes ◽  
Operating Conditions ◽  
Fast Reaction ◽  
Capture Process ◽  
Amine Absorption ◽  
Fast Reaction Rate

Amine absorption technology, in particular that based on the Monoethanolamine (MEA) process, is considered to be viable for low pressure flue gas CO2 capture because of the MEA-CO2 fast reaction rate. MEA absorption processes are associated with high capital and operating cost because a significant amount of energy is required for solvent regeneration and severe operating problems are present such as corrosion and solvent loss and degradation. The overall objective of this study is to evaluate the feasibility of obtaining the heat required for amine absorption for a particular recovery of carbon dioxide. Comparisons among cases were performed to determine the best operating conditions for CO2 capture. An analysis of the lean loading and recovery percent were carried out as well as the different absorber and stripper combinations by using the chemical processes simulator.

scholarly journals Synthesis of a MnO2/Fe3O4/diatomite nanocomposite as an efficient heterogeneous Fenton-like catalyst for methylene blue degradation

2018 ◽  
Vol 9 ◽  
pp. 1940-1950 ◽  
Author(s):  
Zishun Li ◽  
Xuekun Tang ◽  
Kun Liu ◽  
Jing Huang ◽  
Yueyang Xu ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Cost Efficiency ◽  
Reaction Rate ◽  
Organic Pollutant ◽  
Layer By Layer ◽  
Heterogeneous Fenton ◽  
Fast Reaction ◽  
Methylene Blue Degradation ◽  
Ph Range ◽  
Fast Reaction Rate

Heterogeneous Fenton-like catalysts with the activation of peroxymonosulfate (PMS), which offer the advantages of fast reaction rate, wide functional pH range and cost efficiency, have attracted great interest in wastewater treatment. In this study, a novel magnetic MnO2/Fe3O4/diatomite nanocomposite is synthesized and then used as heterogeneous Fenton-like catalyst to degrade the organic pollutant methylene blue (MB) with the activation of PMS. The characterization results show that the Fe3O4 nanoparticles and nanoflower-like MnO2 are evenly distributed layer-by-layer on the surface of diatomite, which can be readily magnetically separated from the solution. The as-prepared catalyst, compared with other Fenton-like catalysts, shows a superb MB degradation rate of nearly 100% in 45 min in the pH range of 4 to 8 and temperature range of 25 to 55 °C. Moreover, the nanocomposite shows a good mineralization rate of about 60% in 60 min and great recyclability with a recycle efficiency of 86.78% after five runs for MB. The probable mechanism of this catalytic system is also proposed as a synergistic effect between MnO2 and Fe3O4.

Measurement of Hexoses and Pentoses, Singly or in Combination, with o-Anisidine

1973 ◽  
Vol 19 (6) ◽  
pp. 597-601 ◽  
Author(s):  
Jesse F Goodwin ◽  
Hugh Y Yee
Keyword(s):  
Reaction Rate ◽  
Serum Glucose ◽  
Fast Reaction ◽  
Fast Reaction Rate

Abstract Hexoses and pentoses can be measured either singly or in combination, with an o-anisidine reagent. It has the advantages of a fast reaction rate and relatively little interference from hexoses (Amax = 660 nm) in the measurement of pentoses. A simple subtraction of absorbance attributable to glucose at the maximum for pentoses (465 nm) is sufficient for satisfactory pentose estimation in urine. The method has been automated, and results compare favorably with those from an automated procedure for the measurement of serum glucose in which hexokinase is used, and also with those from a colorimetric aniline method for measurement of pentoses in urine. Interferences and procedural variables are discussed. Urinary pentose and hexose values for normal infants are reported.

Automated Stopped-Flow Systems for Fast Reaction-Rate Methods

1977 ◽  
Vol 13 (2) ◽  
pp. 165-259 ◽  
Author(s):  
S. R. Crouch ◽  
F. J. Holwr ◽  
P. K. Notz ◽  
P. M. Beckwith
Keyword(s):  
Reaction Rate ◽  
Stopped Flow ◽  
Fast Reaction ◽  
Flow Systems ◽  
Fast Reaction Rate

scholarly journals Synthesis and in vitro anti breast cancer activity of some novel 1,5-benzothiazepine derivatives

2012 ◽  
Vol 77 (6) ◽  
pp. 725-731 ◽  
Author(s):  
K.L. Ameta ◽  
Nitu Rathore ◽  
Biresh Kumar
Keyword(s):  
Breast Cancer ◽  
Reaction Rate ◽  
Simple Procedure ◽  
Cancer Cell Line ◽  
Spectroscopic Studies ◽  
Human Breast ◽  
Fast Reaction ◽  
Reaction Conditions ◽  
Fast Reaction Rate

The title compounds 3a-j, substituted 1,5-benzothiazepines were synthesized by the condensation of variously substituted chalcones 1 and 2- aminothiophenol 2 via conventional as well as non-conventional inorganic solid support microwave irradiation methods. The non-conventional protocol offers several advantages such as simple procedure, fast reaction rate, mild reaction conditions and improved yields compared to conventional methods. The structures of the products 3a-j were established by elemental analysis, FTIR, 1H-NMR, 13C-NMR and mass spectroscopic studies. The synthesized compounds have also been evaluated for the cytotoxicity against human breast cancer cell line MDA-MB-435 with some exhibiting in vitro anti-breast cancer activities.

scholarly journals A Versatile Method for Preparing Polysaccharide Conjugates via Thiol-Michael Addition

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1905
Author(s):  
Junyi Chen ◽  
Xutao Ma ◽  
Kevin J. Edgar
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Synthetic Approach ◽  
Renewable Materials ◽  
Fast Reaction ◽  
Michael Additions ◽  
Antimicrobial Performance ◽  
A Charge ◽  
Post Modification ◽  
Fast Reaction Rate

Polysaccharide conjugates are important renewable materials. If properly designed, they may for example be able to carry drugs, be proactive (e.g., with amino acid substituents) and can carry a charge. These aspects can be particularly useful for biomedical applications. Herein, we report a simple approach to preparing polysaccharide conjugates. Thiol-Michael additions can be mild, modular, and efficient, making them useful tools for post-modification and the tailoring of polysaccharide architecture. In this study, hydroxypropyl cellulose (HPC) and dextran (Dex) were modified by methacrylation. The resulting polysaccharide, bearing α,β-unsaturated esters with tunable DS (methacrylate), was reacted with various thiols, including 2-thioethylamine, cysteine, and thiol functional quaternary ammonium salt through thiol-Michael addition, affording functionalized conjugates. This click-like synthetic approach provided several advantages including a fast reaction rate, high conversion, and the use of water as a solvent. Among these polysaccharide conjugates, the ones bearing quaternary ammonium salts exhibited competitive antimicrobial performance, as supported by a minimum inhibitory concentration (MIC) study and tracked by SEM characterization. Overall, this methodology provides a versatile route to polysaccharide conjugates with diverse functionalities, enabling applications such as antimicrobial activity, gene or drug delivery, and biomimicry.

Kinetic and mechanistic aspects of the oxidation of chlorophenols by ozone

1997 ◽  
Vol 35 (4) ◽  
pp. 65-72 ◽  
Author(s):  
M. A. Boncz ◽  
H. Bruning ◽  
W. H. Rulkens ◽  
E. J. R. Sudhölter ◽  
G. H. Harmsen ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Advanced Oxidation Processes ◽  
Reaction Rate ◽  
Radical Mechanism ◽  
Radical Scavenger ◽  
Strong Indication ◽  
Fast Reaction ◽  
Oxidation Processes ◽  
Carbonate Concentration ◽  
Kinetics Of

In Advanced oxidation processes (AOPs) radicals are considered to play an important role. Organic contaminations can in AOPs generally be converted to carbon dioxide, water, etc. The most important limitation to the application of AOPs, however, is their high costs, especially when complete mineralisation of the pollutants is pursued. The costs can be reduced by using the oxidant more efficiently, which can be achieved by introducing selectivity. Kinetic and mechanistic data are the basic requirements for optimization of the process. In this work, the influence of several different parameters (temperature, pH, UV irradiation and carbonate concentration) on the kinetics of the degradation ofortho -chlorophenol and para-chlorophenol by ozone was investigated. The pH is the most important parameter. Strongly related to the pH is the degree of ionisation of the phenol, which might be of importance since the shift from a slow to a fast reaction occurs at a higher pH in the case of para-chlorophenol as compared to the case with the more acidic ortho-chlorophenol. A strong indication for a radical mechanism is found in the decrease of the reaction rate in the presence of carbonate, a well known radical scavenger. A further indication is seen in the first step of the reaction, which is dechlorination of the aromatic compound.

scholarly journals The reaction of nitrogen monoxide with the haemocyanins of the crayfish Astacus leptodactylus and the snail Helix pomatia

1989 ◽  
Vol 262 (1) ◽  
pp. 253-260
Author(s):  
J P Tahon ◽  
C Gielens ◽  
C Vinckier ◽  
R Witters ◽  
M De Ley ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Rate Increase ◽  
Formation Rate ◽  
Helix Pomatia ◽  
Nitrogen Monoxide ◽  
Astacus Leptodactylus ◽  
Fast Reaction ◽  
Bridging Ligand ◽  
Snail Helix Pomatia ◽  
Hasselbalch Equation

The rate of the reaction of Astacus leptodactylus methaemocyanin with NO follows the Henderson-Hasselbalch equation with a pKa of 5.85, suggesting that one imidazole ligand of Cu was exchanged for NO. The reaction is blocked by F- as a bridging ligand. The same imidazole residue might be responsible for the decomposition of nitrosylhaemocyanin, [Cu1NO+CuII], with an unlocated binding site for NO, into methaemocyanin and NO, as the rate increase with pH. NO could react preferentially with CuA of Helix pomatia methaemocyanin, CuA′IICuBII, as it possibly has only two histidine ligands instead of the three of CuA in Astacus haemocyanin. This difference might explain the higher formation rate and the much greater stability of Helix nitrosylhaemocyanin. The fast reaction is governed by a pKa of 6.80, probably of a bridging mu-aquo ligand. With F- or a mu-hydroxo bridging ligand a low reaction rate was still observed, in contrast with Astacus methaemocyanin. Helix nitrosylhaemocyanin was transformed by N3- into methaemocyanin with the liberation of N2 and N2O. This methaemocyanin could almost quantitatively be regenerated with H2O2. Helix nitrosylhaemocyanin was only partially regenerated by a direct treatment with H2O2 and almost quantitatively by HONH2 in a similar fairly fast reaction, followed by a much slower one.

scholarly journals Regulating the Homogeneity of Thiol-Maleimide Michael-Type Addition-Based Hydrogels Using Amino Biomolecules

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 206
Author(s):  
Yu Guo ◽  
Jie Gu ◽  
Yuxin Jiang ◽  
Yanyan Zhou ◽  
Zhenshu Zhu ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Reaction Rate ◽  
Side Chain ◽  
Short Peptides ◽  
Poly Ethylene Glycol ◽  
Fast Reaction ◽  
Gelation Kinetics ◽  
Michael Type Addition ◽  
Poly Ethylene ◽  
Kinetics Of

Poly(ethylene glycol) (PEG)-based synthetic hydrogels based on Michael-type addition reaction have been widely used for cell culture and tissue engineering. However, recent studies showed that these types of hydrogels were not homogenous as expected since micro domains generated due to the fast reaction kinetics. Here, we demonstrated a new kind of method to prepare homogenous poly(ethylene glycol) hydrogels based on Michael-type addition using the side chain amine-contained short peptides. By introducing such a kind of short peptides, the homogeneity of crosslinking and mechanical property of the hydrogels has been also significantly enhanced. The compressive mechanical and recovery properties of the homogeneous hydrogels prepared in the presence of side chain amine-contained short peptides were more reliable than those of inhomogeneous hydrogels while the excellent biocompatibility remained unchanged. Furthermore, the reaction rate and gelation kinetics of maleimide- and thiol-terminated PEG were proved to be significantly slowed down in the presence of the side chain amine-contained short peptides, thus leading to the improved homogeneity of the hydrogels. We anticipate that this new method can be widely applied to hydrogel preparation and modification based on Michael-type addition gelation.

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