Identification of saccharides in anthocyanins and other flavonoids

1961 ◽  
Vol 14 (4) ◽  
pp. 586 ◽  
Author(s):  
BV Chandler ◽  
KA Harper
Keyword(s):  
Chemical Reactions ◽  
Paper Chromatography ◽  
The Other ◽  
Flavonoid Glycosides ◽  
Hydroxyl Groups ◽  
Absolute Identification ◽  
Yield Information ◽  
Cyclic Systems ◽  
The Absolute

Procedures have been developed for the determination of the type and location of sugar units present in anthocyanins and other flavonoid glycosides. These procedures are based on standard chemical reactions and have been adapted to a microscale using paper chromatography. Individual flavonoids were found to respond variably to enzymic and chemical hydrolyses, which therefore yield information of limited use only. On the other hand, controlled oxidation has been shown to provide information on the type and position of sugar units attached to the flavonoid nucleus. Degradation using peroxide releases the sugars at the 3-position ; permanganate treatment releases sugars attached to readily ruptured cyclic systems ; and ozonolysis releases sugars attached to phenolic and enolic hydroxyl groups. These three techniques, when used together, can result in the absolute identification of anthocyanins and most other flavonoid glycosides.

scholarly journals The monaural threshold: the effect of subliminal and audible contralateral and ipsilateral stimuli

1940 ◽  
Vol 128 (851) ◽  
pp. 144-152 ◽  
Keyword(s):  
Experimental Technique ◽  
Natural Frequencies ◽  
The Other ◽  
Resonance Theory ◽  
Simultaneous Application ◽  
Yield Information ◽  
Subliminal Stimulation ◽  
Critical Intensity ◽  
Stimulation Of

Using the experimental technique developed during earlier work on the binaural threshold (Hughes 1938), the effect on the monaural threshold of subliminal notes has now been investigated. It was hoped that the experiments, when carried out with two notes of various frequency differences, would yield information on the extent to which the cochlear resonators postulated by the resonance theory could be influenced by notes of frequencies different from their natural frequencies, and thus permit the determination of the amount of damping to which they were subject. It was anticipated that the threshold of a note of given frequency would be lowered by the simultaneous application to the ear of a second subliminal note provided that the two frequencies were not too far apart. In practice it was found that no matter how different the frequencies, a process of central summation produced such lowering of threshold. The purely physical question of what range of resonators in the cochlea responds to a given exciting tone cannot therefore be investigated in this way. The lowering of threshold of one ear due to simultaneous subliminal stimulation of the other (Hughes 1938) made it of interest to investigate the case when the note applied to the second ear is audible. Previous workers (e.g. Harvey Fletcher 1929) have shown that when a “ masking tone” is well above threshold no change of contralateral threshold is produced. The experimental results described below bear this out in a general way, but the presence of a weak audible tone causes so much difficulty in determining the contralateral threshold that it is not possible to find any critical intensity at which summation ceases. When, however, the two notes were in unison a rise in this threshold occurred, the explanation of which is discussed later.

A procedure for the absolute identification of anthocyanins: the pigments of blackcurrant fruit

1962 ◽  
Vol 15 (1) ◽  
pp. 114 ◽  
Author(s):  
BV Chandler ◽  
KA Harper
Keyword(s):  
Paper Chromatography ◽  
Column Chromatography ◽  
Absolute Identification ◽  
Black Currant ◽  
Anthocyanin Pigments ◽  
The Absolute ◽  
Blackcurrant Fruit

A procedure is outlined for the isolation of pure anthocyanins and their identification without recourse to comparison with reference glycosides. The isolation involves cellulose and polyamide column chromatography and the identification depends on simple but selective oxidative and hydrolytic reactions, adapted to a microscale using paper chromatography. By this method the anthocyanin pigments present in extracts of black currant fruit have been unequivocally identified as cyanidin and delphinidin, their 3-glucosides and 3-rutinosides.

scholarly journals XIV. Magnetization of liquids

1896 ◽  
Vol 187 ◽  
pp. 533-549 ◽  
Keyword(s):  
Accurate Determination ◽  
The Other ◽  
Other Hand ◽  
Absolute Measure ◽  
Magnetizing Force ◽  
The Absolute

The magnetization of liquids is a subject which has been examined by several methods, and although the relative values of the coefficient of magnetization for different bodies agree tolerably accurately, still there are large discrepancies in the absolute values given by different observers. An account of nearly all these methods is given in Wiedemann’s ‘Electricität,’ vol. 3. The difficulty of finding the magnetizing force is no doubt a serious objection to the accurate determination of the coefficient k in absolute measure by magnetometer methods, which, on the other hand, are very convenient for finding the relative values of k for different bodies when magnetized by large forces.

scholarly journals CHEMICAL STUDIES ON BACTERIAL AGGLUTINATION

1936 ◽  
Vol 63 (5) ◽  
pp. 737-744 ◽  
Author(s):  
Michael Heidelberger ◽  
Elvin A. Kabat
Keyword(s):  
Specific Antibody ◽  
Horse Serum ◽  
The Other ◽  
Type I ◽  
Specific Polysaccharide ◽  
Chemical Studies ◽  
The Absolute ◽  
Bacterial Agglutination

1. The absolute, quantitative agglutinin method has been used for the determination of the presence or absence of small amounts of specific polysaccharide in pneumococcus variants. 2. A technique is described for the removal of group specific antibody from antipneumococcus horse serum. 3. The type specific anticarbohydrate agglutinin and precipitin are not only present in identical amounts in Type I antipneumococcus horse serum, but a reduction in one is also accompanied by a quantitatively identical reduction in the other, providing evidence for their actual identity. In purified antibody solutions somewhat more agglutinin than precipitin is found, possibly owing to alteration of a portion of the antibody in the process of purification.

scholarly journals Semi-Empirical Determination of the Position of RRAB Stars on The H-R Diagram

1998 ◽  
Vol 11 (1) ◽  
pp. 373-373
Author(s):  
J. Jurcsik ◽  
G. Kovács
Keyword(s):  
Light Curve ◽  
Light Curves ◽  
The Other ◽  
Physical Parameters ◽  
Present Sample ◽  
Large Numbers ◽  
Empirical Determination ◽  
The Absolute ◽  
Semi Empirical

In a recent series of papers, it was shown that the metallicity and the absolute V, I and K mean magnitudes of RRab stars can be accurately calculated using only their periods and the low order Fourier parameters of the V light curves. The application of these formulae in conjunction with the synthetic colours of the model atmospheres and with the theoretical pulsation periods enables us to determine all the basic physical parameters (i.e. logL, logT, logM and [Fe/H]) of any variable with an accurate light curve. As a result, we might trace evolutionary tracks on the H—R diagram by plotting the stars with the same mass and metallicity. From a present sample of nearly 300 stars, signs of differences in the evolutionary statescan be suspected but not yet proven. The accumulation of large numbers of precise light and colour curves, onthe one hand, will further improve the empirical formulae and therefore theaccuracy of the derived parameters and, on the other hand, will increase our chances of constructing better-populated empirical evolutionary tracks.

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.

Polarity Determination in Sphalerite and Wurtzite Structures

1990 ◽  
Vol 48 (2) ◽  
pp. 500-501
Author(s):  
Stuart McKernan ◽  
C. Barry Carter
Keyword(s):  
Opposite Polarity ◽  
Single Domain ◽  
Polar Material ◽  
Electron Microscopic ◽  
Dynamical Interaction ◽  
X Ray ◽  
Polarity Determination ◽  
The Absolute ◽  
Microscopic Techniques

The determination of the absolute polarity of a polar material is often crucial to the understanding of the defects which occur in such materials. Several methods exist by which this determination may be performed. In bulk, single-domain specimens, macroscopic techniques may be used, such as the different etching behavior, using the appropriate etchant, of surfaces with opposite polarity. X-ray measurements under conditions where Friedel’s law (which means that the intensity of reflections from planes of opposite polarity are indistinguishable) breaks down can also be used to determine the absolute polarity of bulk, single-domain specimens. On the microscopic scale, and particularly where antiphase boundaries (APBs), which separate regions of opposite polarity exist, electron microscopic techniques must be employed. Two techniques are commonly practised; the first [1], involves the dynamical interaction of hoLz lines which interfere constructively or destructively with the zero order reflection, depending on the crystal polarity. The crystal polarity can therefore be directly deduced from the relative intensity of these interactions.

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.

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