Determination of N-Acetyl-p-Aminophenol in Plasma

1968 ◽  
Vol 14 (9) ◽  
pp. 882-889 ◽  
Author(s):  
J I Routh ◽  
N A Shane ◽  
E G Arredondo ◽  
W D Paul
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Plasma Levels ◽  
The Other ◽  
Absorption Peak ◽  
Isosbestic Point ◽  
Differential Absorption ◽  
Salicylic Acids

Abstract Two methods for the determination of N-acetyl-p-aminophenol (APAP) in plasma that differ in principle from the diazotization procedure of Brodie and Axelrod (1) are described. One method based on the differential absorption peak of APAP at 266 mµ, which corresponds to the isosbestic point of common drugs such as acetylsalicylic and salicylic acids, is simple and most specific for APAP. The other method employs a free-radical dye diphenylpicrylhydrazyl which extracts a hydrogen atom from the APAP molecule and is progressively decolorized. The dye method is the least complex and most sensitive. All three methods exhibited satisfactory replication, recovery of added APAP, and comparable plasma levels of the drug.

Determination of Superoxide Free Radical Ion and Hydrogen Peroxide as Products of Photosynthetic Oxygen Reduction

1975 ◽  
Vol 30 (1-2) ◽  
pp. 53-57 ◽  
Author(s):  
Erich Elstner ◽  
Claus Stoffer ◽  
Adelheid Heupel
Keyword(s):  
Heat Treatment ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Free Radical ◽  
Oxygen Reduction ◽  
The Other ◽  
Keto Acids ◽  
Superoxide Free Radical ◽  
Photosynthetic Oxygen

Abstract Formation of Nitrite from Hydroxylamine in the presence of illuminated chloroplast lamellae is inhibited by superoxide dismutase but not by catalase, indicating that the superoxide free radical ion and not H2O2 is responsible for the oxidation of hydroxylamine. Decarboxylation of α-keto acids on the other hand is strongly inhibited by catalase but only slightly by superoxide dismutase. Light-dependent hydroxylamine oxidation and decarboxylation of α-keto acids can be used, therefor, as specific and sensitive probes for the determination of either the superoxide free radical ion or hydrogen peroxide, respectively. Photosynthetic oxygen reduction in the presence of ferredoxin, (monitored by the above method) yields both H2O2 and O2·-. The addition of an oxygen reducing factor (ORF, solubilized by heat - treatment of washed chloroplast lamellae) instead of ferredoxin, however, stimulates only the production of H2O2 , while O2·- - formation is not observed. The cooperation of ferredoxin and ORF during photosynthetic oxygen reduction by chloroplast lamellae apparently produces H2O2 not only by dismutation of O2·-, but also by a separate mechanism involving ORF.

scholarly journals Perbandingan Pengukuran Kadar Vitamin C Menggunakan Spektrofotometri UV-Vis pada Panjang Gelombang UV dan Visible

2019 ◽  
Vol 1 (2) ◽  
pp. 77-81
Author(s):  
Khoirul Ngibad ◽  
Dheasy Herawati
Keyword(s):  
Free Radical ◽  
Detection Limit ◽  
Vitamin C ◽  
Calibration Curve ◽  
Oxidation Reaction ◽  
Limit Of Detection ◽  
The Other ◽  
Visible Wavelength ◽  
Food And Beverage

Vitamin C is a source of antioxidants which has a primary function to inhibit the occurrence of an oxidation reaction and inhibit a free radical. The source of vitamin C can be found in food and beverage. This study aims to compare the measurement of vitamin C levels using a UV-Vis spectrophotometer at UV and Visible wavelength. The method used in this study was the UV-Vis spectrophotometry method. The analysis of vitamin C levels at UV wavelength 266 nm and Visible wavelength 494 nm with a calibration curve range 0.3 to 0.8 mg/L. Validation of the methods studied included: linearity, detection limits, quantization limits, and precision. The results showed that the measurement of vitamin C levels at UV wavelengths resulted in the linearity of concentrations of 0.2 - 0.8 mg / L, the limit of detection of 0.05 mg/L, the limit of quantization of 0.17 mg/L and level of precision with RSD to 0.2015. On the other hand, the measurement of vitamin C levels in the Visible wavelength produced linearity from concentrations of 0.3 to 0.8 mg/L, the detection limit of 0.05 mg/L, quantization limit of 0.18 mg/L and the level of precision with RSD of 1.0489. Thus, the determination of vitamin C levels in samples using a UV-Vis spectrophotometer was preferred to be measured at UV wavelengths.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 330-331
Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose
Keyword(s):  
High Order ◽  
Simulation Technique ◽  
The Other ◽  
Image Simulation ◽  
Diffraction Vector ◽  
Burgers Vector ◽  
Weak Beam ◽  
Beam Image ◽  
Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

Determination of Factor XIII Activity and of Factor XIII Inhibitors Using an Ammonium-Sensitive Electrode

1983 ◽  
Vol 50 (02) ◽  
pp. 563-566 ◽  
Author(s):  
P Hellstern ◽  
K Schilz ◽  
G von Blohn ◽  
E Wenzel
Keyword(s):  
Factor Xiii ◽  
Normal Subjects ◽  
The Other ◽  
Activity Measurement ◽  
Factor Xiii Deficiency ◽  
Assay Procedure ◽  
Stabilization Factor ◽  
Release Method ◽  
Sensitive Electrode

SummaryAn assay for rapid factor XIII activity measurement has been developed based on the determination of the ammonium released during fibrin stabilization. Factor XIII was activated by thrombin and calcium. Ammonium was measured by an ammonium-sensitive electrode. It was demonstrated that the assay procedure yields accurate and precise results and that factor XIII-catalyzed fibrin stabilization can be measured kinetically. The amount of ammonium released during the first 90 min of fibrin stabilization was found to be 7.8 ± 0.5 moles per mole fibrinogen, which is in agreement with the findings of other authors. In 15 normal subjects and in 15 patients suffering from diseases with suspected factor XIII deficiency there was a satisfactory correlation between the results obtained by the “ammonium-release-method”, Bohn’s method, and the immunological assay (r1 = 0.65; r2= 0.70; p<0.01). In 3 of 5 patients with paraproteinemias the values of factor XIII activity determined by the ammonium-release method were markedly lower than those estimated by the other methods. It could be shown that inhibitor mechanisms were responsible for these discrepancies.

Recent advances in Minisci-type reactions and applications in organic synthesis

2020 ◽  
Vol 24 ◽  
Author(s):  
Wengui Wang ◽  
Shoufeng Wang
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Organic Synthesis ◽  
Radical Reactivity ◽  
Atom Loss ◽  
Radical Generation ◽  
In Situ Generation ◽  
Thermal Cleavage ◽  
Synthetic Chemist

Abstract:: Minisci-type reactions have become widely known as reactions that involve the addition of carbon-centered radicals to basic heteroarenes followed by formal hydrogen atom loss. While the originally developed protocols for radical generation remain in active use today, in recent years by a new array of radical generation strategies allow use of a wider variety of radical precursors that often operate under milder and more benign conditions. New transformations based on free radical reactivity are now available to a synthetic chemist looking to utilize a Minisci-type reaction. Radical-generation methods based on photoredox catalysis and electrochemistry, which utilize thermal cleavage or the in situ generation of reactive radical precursors, have become popular approaches. Our review will cover the remarkably literature that has appeared on this topic in recent 5 years, from 2015-01 to 2020-01, in an attempt to provide guidance to the synthetic chemist, on both the challenges that have been overcome and applications in organic synthesis.

Quantum Resonances: Line Profiles and Dynamics

2003 ◽  
Vol 68 (3) ◽  
pp. 529-553 ◽  
Author(s):  
Ivana Paidarová ◽  
Philippe Durand
Keyword(s):  
Hydrogen Atom ◽  
Operator Theory ◽  
Quantum Dynamics ◽  
Line Profiles ◽  
Static Electric Field ◽  
Reversal Effect ◽  
Quantum Resonances ◽  
Energy Dependent ◽  
Effective Hamiltonians

The wave operator theory of quantum dynamics is reviewed and applied to the study of line profiles and to the determination of the dynamics of interacting resonances. Energy-dependent and energy-independent effective Hamiltonians are investigated. The q-reversal effect in spectroscopy is interpreted in terms of interfering Fano profiles. The dynamics of an hydrogen atom subjected to a strong static electric field is revisited.

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