scholarly journals Kinetic Analysis of the Permeability of Human Erythrocytes to NH4Cl

1968 ◽  
Vol 51 (4) ◽  
pp. 579-587 ◽  
Author(s):  
F. R. Hunter
Keyword(s):  
Kinetic Analysis ◽  
Human Erythrocytes ◽  
The Other ◽  
A Value ◽  
Straight Line ◽  
Family Of Curves ◽  
Series Of Experiments

A densimeter technique was used to make a kinetic analysis of the rate of swelling of human erythrocytes suspended in 1% NaCl following successive additions of NH4Cl. Two series of experiments were performed, one in the absence of and the other in the presence of 6 x 10-4 M NaHCO3. An analysis of the data using Widdas's equations gave a family of curves in each instance. When LeFevre's equation was used with a value of ø = 1.3 isotones, a straight line was obtained with both series of data. It is concluded that this system shows carrier kinetics.

The Estimation Of α2-Antiplasmin By Means Of Synthetic Substrates; Kinetic Analysis And Optimization Of The Method

1981 ◽  
Author(s):  
G Dooijewaard ◽  
C Kluft
Keyword(s):  
Kinetic Analysis ◽  
Equilibrium Constant ◽  
Initial Rate ◽  
Enzyme Inhibitor ◽  
The Other ◽  
Scatchard Plot ◽  
Fixed Amount ◽  
Inhibitor Complex ◽  
Straight Line ◽  
Alternative Approach

Generally the concentration of an enzyme inhibitor in plasma is estimated as follows: plasma, in decreasing dilutions, is incubated with a fixed amount of enzyme. When the inhibitor has been irreversibly converted to its enzyme- inhibitor complex, the excess of enzyme is estimated as the initial rate (v) of its activity with a synthetic substrate. The plot of v against plasma dilution results in a straight line which intercepts the abscissa at the point of equivalency.Contrary to the above method, for the estimation of α2-antiplasmin (A) in plasma, the excess of plasmin (Pi) is measured immediately after the attainment of a fast equilibrium between Pi, A and the reversible complex PlA (equilibrium constant Ki). Since this is attained almost two orders of magnitude faster than the irreversible reactions of PI with inhibitors in plasma other than A, the assay,thus, becomes more specific for A.The results of the kinetic analysis are; 1. The involvement of the reversible equilibrium causes the plot of v against plasma dilution to be a hyperbola instead of a straight line. The hyperbolic shape of the plot becomes more pronounced at higher ratios of K, over Pi concentration. Moreover, the synthetic substrati (S) shifts the equilibrium to dissociation, thereby apparently increasing the Ki by a factor of (1 + S/Km). 2. Pi inhibitors in plasma other than A, interfere Relatively more at low plasma dilutions. Because, coincidently, this interference makes the hyperbola resemble a straight line, the contribution of the other inhibitors is largely overlooked.It is concluded that the usual assay may have its merit as a routine bioassay, provided the conditions are chosen carefully. As an alternative approach it is recommended to titrate a fixed amount of plasma with increasing concentrations of Pi and to evaluate the initial velocities in a Scatchard plot. In this way a more reliable point of equivalency and in addition the Ki value can be obtained

Effect of Catfish Bone Paste on the Properties of Steamed Bread

2014 ◽  
Vol 881-883 ◽  
pp. 757-760
Author(s):  
Xiao Qing Ren ◽  
Li Zhen Ma ◽  
Xin Yi He
Keyword(s):  
Weight Loss ◽  
Specific Volume ◽  
Cell Structure ◽  
The Other ◽  
Gas Cell ◽  
A Value ◽  
Crumb Structure ◽  
Steamed Bread ◽  
Different Levels ◽  
Structure Properties

The objective of this study was to examine the effect of different levels of catfish bone paste to flour on the physicochemical, textural and crumb structure properties of steamed bread. Six different levels (0, 1, 3, 5, 7,10 %) of catfish bone paste to flour were used in the formulation of the steamed bread. The results showed that the weight loss and TTA of steamed bread decreased with an increase in the levels of the catfish bone paste. On the other hand, the pH increased with an increase in the levels of the catfish bone paste. The specific volume, hardness, chewiness and gas cell structure in the crumb of steamed bread with catfish bone paste at 5% supplementation level were better. Thus, a value of 5% catfish bone paste was considered a better level for incorporation into the steamed bread.

Aortic tortuosity index as a predictor of type A aortic dissection

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
F Scalbert ◽  
O Milleron ◽  
M Para ◽  
R Raffoul ◽  
Q Pellenc ◽  
...  
Keyword(s):  
Aortic Dissection ◽  
Type A ◽  
Ct Scans ◽  
Control Group ◽  
Type A Aortic Dissection ◽  
Total Length ◽  
A Value ◽  
Straight Line ◽  
Patients At Risk ◽  
Geometric Length

Abstract Introduction The risk ok type A aortic dissection (AAD) depends on the degree of aortic wall's alteration, which can result in dilatation or tortuosity. The estimate of this risk relies solely on the evaluation of the diameter of the ascending aorta. Purpose The purpose of this study is to evaluate the presence and importance of aortic tortuosity in patients with type A aortic dissection. Method Postoperative CT scans of patients with type A aortic dissection were compared with CT scans from controls matched for gender and age. After 3D reconstruction, total length (actual distance along aortic center line = Ltot) and geometric length (length of a straight line between start and end of the aortic segment = Lgeo) were measured to calculate the tortuosity index (TI = Ltot / Lgeo). Results Ltot, Lgeo and TI from different aortic segments of the AAD group were higher than in the control group. Ltot and TI of the whole aorta (from aortic valve to bifurcation) were greater in patients with type A aortic dissection (527.7±46.1 mm vs. 475.8±39.7, p<0.0001; and 2.05±0.24 vs. 1.98±0.21, p=0.002 respectively). Total length and TI were greater after exclusion of the ascending part, and a value of this TI >1.3 identifies AAD patients with an accuracy of 74.8% (AUC = 0.792, p<0.0001). TI is altered by risk factors for aortic dissection: it increases with hypertension and age but not by tobacco use, and TI decreases in diabetes. Conclusions Type A aortic dissection is associated with longer aorta and increased aortic tortuosity. This index may help recognize patients at risk for type A aortic dissection. Calculation of tortuosity indexes Funding Acknowledgement Type of funding source: None

scholarly journals Evaluation of equilibrium constants for the interaction of lactate dehydrogenase isoenzymes with reduced nicotinamide-adenine dinucleotide by affinity chromatography

1975 ◽  
Vol 151 (3) ◽  
pp. 631-636 ◽  
Author(s):  
R I Brinkworth ◽  
C J Masters ◽  
D J Winzor
Keyword(s):  
Lactate Dehydrogenase ◽  
Affinity Chromatography ◽  
Equilibrium Constants ◽  
Mouse Tissue ◽  
Rabbit Muscle ◽  
Muscle Lactate ◽  
Sodium Phosphate Buffer ◽  
A Value ◽  
Series Of Experiments ◽  
Reduced Nicotinamide Adenine Dinucleotide

Rabbit muscle lactate dehydrogenase was subjected to frontal affinity chromatography on Sepharose-oxamate in the presence of various concentrations of NADH and sodium phosphate buffer (0.05 M, pH 6.8) containing 0.5 M-NaCl. Quantitative interpretation of the results yields an intrinsic association constant of 9.0 × 104M−1 for the interaction of enzyme with NADH at 5°C, a value that is confirmed by equilibrium-binding measurements. In a second series of experiments, zonal affinity chromatography of a mouse tissue extract under the same conditions was used to evaluate assoication constants of the order 2 × 105M−1, 3 × 105M−1, 4 × 105M−1, 7 × 105M−1 and 2 × 106M−1 for the interaction of NADH with the M4, M3H, M2H2, MH3 and H4 isoenzymes respectively of lactate dehydrogenase.

scholarly journals VIII. On the descending degenerations which follow lesions of the gyrus marginalis and gyrus fornicatus in monkeys

1889 ◽  
Vol 180 ◽  
pp. 331-354
Keyword(s):  
The Other ◽  
Post Mortem ◽  
Cerebral Lesions ◽  
Series Of Experiments ◽  
The Government ◽  
Government Grant

The following paper contains the record of an investigation into the degenerations which follow lesions of the gyrus marginalis and gyrus fornicatus in Monkeys. The work has been carried on under my direction by Mr. France, with the aid of a grant from the Government Grant Fund, and represents part of a long investigation into the degenerations which follow artificially produced cerebral lesions, the material for which has been furnished by cases operated upon in conjunction respectively with Professor V. Horsley and Dr. Sanger Brown. These cases and the physiological results of the operations have already been published in the ‘Philosophical Transactions.’ The experiments here dealt with, twelve in number, comprise only the lesions of the gyrus marginalis and gyrus fornicatus, and, with one exception (case 12), are taken from the series of experiments performed in conjunction with Mr. Horsley. Of the twelve cases, six were of removal, or attempted removal, of the gyrus marginalis, and six of removal, or attempted removal, of the gyrus fornicatus. But in only one or two instances was the lesion, as determined by post-mortem examination, exactly limited to the convolution which it was attempted to remove, for in most cases the adjacent gyrus was to a certain extent involved in the injury. This was especially the case when removal of the gyrus fornicatus had been attempted, on account of its deep situation, and the difficulty of getting at it without some manipulation of the superjacent gyrus. Nevertheless, the removal of one or the other gyrus was sufficiently complete in all the cases here selected to produce characteristic symptoms and characteristic descending degenerations.

scholarly journals XXIII.—On the Disruptive Discharge of Electricity: An Experimental Thesis for the Degree of Doctor of Science, Department A

1878 ◽  
Vol 28 (2) ◽  
pp. 633-671 ◽  
Author(s):  
Alexander Macfarlane
Keyword(s):  
Copper Wire ◽  
Late Summer ◽  
The Other ◽  
Straight Line ◽  
Summer Session ◽  
The Difference ◽  
A Chain ◽  
The One ◽  
Metallic Parts ◽  
The University

The experiments to which I shall refer were carried out in the physical laboratory of the University during the late summer session. I was ably assisted in conducting the experiments by three students of the laboratory,—Messrs H. A. Salvesen, G. M. Connor, and D. E. Stewart. The method which was used of measuring the difference of potential required to produce a disruptive discharge of electricity under given conditions, is that described in a paper communicated to the Royal Society of Edinburgh in 1876 in the names of Mr J. A. Paton, M. A., and myself, and was suggested to me by Professor Tait as a means of attacking the experimental problems mentioned below.The above sketch which I took of the apparatus in situ may facilitate tha description of the method. The receiver of an air-pump, having a rod capable of being moved air-tight up and down through the neck, was attached to one of the conductors of a Holtz machine in such a manner that the conductor of the machine and the rod formed one conducting system. Projecting from the bottom of the receiver was a short metallic rod, forming one conductor with the metallic parts of the air-pump, and by means of a chain with the uninsulated conductor of the Holtz machine. Brass balls and discs of various sizes were made to order, capable of being screwed on to the ends of the rods. On the table, and at a distance of about six feet from the receiver, was a stand supporting two insulated brass balls, the one fixed, the other having one degree of freedom, viz., of moving in a straight line in the plane of the table. The fixed insulated ball A was made one conductor with the insulated conductor of the Holtz and the rod of the receiver, by means of a copper wire insulated with gutta percha, having one end stuck firmly into a hole in the collar of the receiver, and having the other fitted in between the glass stem and the hollow in the ball, by which it fitted on to the stem tightly. A thin wire similarly fitted in between the ball B and its insulating stem connected the ball with the insulated half ring of a divided ring reflecting electrometer.

Effects of Light on Schooling and Feeding of Jack Mackerel, Trachurus symmetricus

1968 ◽  
Vol 25 (2) ◽  
pp. 393-407 ◽  
Author(s):  
John R. Hunter
Keyword(s):  
Motion Picture ◽  
Nearest Neighbor ◽  
Motion Pictures ◽  
Separation Distance ◽  
The Other ◽  
Angular Deviation ◽  
Jack Mackerel ◽  
A Value

Schools of six jack mackerel each were photographed with infrared film at eight levels of luminance and also in darkness. Three indices were used to measure the behavior of the school from motion pictures. Two of the indices, mean distance to nearest neighbor and mean separation distance, were measures of the distances between individuals in a school; the other, mean angular deviation, was a measure of differences in orientation between individuals. A value for each index was calculated for each motion picture frame.From 12.1 to 6 × 10−6 ft-L no differences existed in the angular deviation of the school or in the distances between fish. At 6 × 10−7 ft-L the intervals between fish were much larger than at higher levels of brightness and groups showed little uniformity in their orientation. Below 6 × 10−7 ft-L (darkness) schools were dispersed and the distributions of values of angular deviation were random.The ability of jack mackerel to feed on live adult Artemia was also tested at eight levels of luminance and in darkness. The number of Artemia eaten at 6 × 10−5 ft-L was about half of that eaten at the normal daytime level of 12.1 ft-L. Few Artemia were eaten at 6 × 10−7 ft-L and none in darkness.Comparison of these data with measurements of light in the sea indicated that jack mackerel probably would be able to maintain schools near the surface on a moonless starlit night and that they probably could feed effectively near the surface on a full moonlight night.

The Mechanical Performance Evaluation of a Mechanism with Curved Edge Driving Component

2013 ◽  
Vol 834-836 ◽  
pp. 1290-1294
Author(s):  
Xin Qin Liu
Keyword(s):  
Performance Evaluation ◽  
Fast Moving ◽  
Mechanical Performance ◽  
Gain Coefficient ◽  
The Other ◽  
Force Transmission ◽  
Transmission Performance ◽  
Connecting Rod ◽  
Numerical Examples ◽  
Straight Line

Mechanicalmethods were employed to study the motion and force transmission performance ofa kind of connecting rod slider mechanism with a curved edge driving component.The deduction methods and the computation formulae of the slider displacement,velocity, acceleration and the executive force gain coefficient were given.Considering two cases of the driving components with straight line edge andexponential function edge, the numerical examples was computed respectively,the results show that the former one is suitable for the force transmission andcan be used in the grip design and the other one is suitable for the motiontransmission which can be used in the fast moving mechanism

scholarly journals XXI. On the construction of a new calorimeter for determining the radiating powers of surfaces in air; and its application to the surfaces of various mineral substances

1860 ◽  
Vol 150 ◽  
pp. 379-408
Keyword(s):  
Surrounding Medium ◽  
The Other ◽  
Absolute Amount ◽  
Present Communication ◽  
Atmospheric Air ◽  
Glass Bulb ◽  
Heated Body ◽  
Series Of Experiments ◽  
Quantity Of Heat ◽  
Limited Induction

When my paper on the Conductivity of various Substances was presented to the Society, it was intimated to me on the part of the Council of the Society, that it might be advisable to determine absolute instead of relative conductivities, the latter being alone attempted in my previous experiments. It has been partly in consequence of this intimation, as well as from the desire to make my investigations the more complete, that I have given my attention to the construction of a calorimeter which might serve for this purpose. The present communication contains a description of this instrument, with the results which it has enabled me to obtain respecting the absolute quantities of heat which emanate from the surfaces of certain substances under given conditions. 1. When a body is placed in atmospheric air (or any gas), the quantity of heat which is lost from its surface in a given time, when its temperature is higher than that of the surrounding medium, will be greater than if it were placed in a vacuum, other conditions remaining unaltered. In the latter case the heat escapes by simple radiation; in the other case a portion of the heat also escapes in consequence of the contact of the air with the surface of the heated body. Dulong and Petit ascertained by a careful series of experiments, the laws according to which the mercury contained in the bulb of a thermometer cools, or those which govern the quantity of heat which escapes from the surface of the containing bulb, when placed in a vacuum, in air, or in several kinds of gases. These experiments were made with the glass bulb naked, and also when it was silvered, so that the laws of radiation which they established were strictly in reference only to surfaces of glass and those of silver. Certain laws were identical in both these cases, and hence it was concluded, though by a limited induction, that the same laws were applicable to all other surfaces. They did not, however, give the absolute quantity of heat which, under given circumstances, and in a given time, emanates from the surfaces of the glass or silver with which they experimented. The instrument which I have constructed gives very easily this absolute amount of heat, as I believe, with very approximate accuracy.

Lead and calcium transport in human erythrocyte

1999 ◽  
Vol 18 (5) ◽  
pp. 327-332 ◽  
Author(s):  
J V Calderón-Salinas ◽  
M A Quintanar-Escorcia ◽  
M T González-Martínez ◽  
C E Hernández-Luna
Keyword(s):  
Transport System ◽  
Human Erythrocyte ◽  
Calcium Transport ◽  
Human Erythrocytes ◽  
The Other ◽  
Erythrocyte Ghosts ◽  
Passive Transport ◽  
Ca Uptake

In this paper we report the lead (Pb) and calcium (Ca) uptake by erythrocyte ghosts. In both cases the transport was carried out by a passive transport system with two kinetic components (Michaelis-Menten and Hill). Pb and Ca were capable of inhibiting the transport of the other metal in a non-competitive way. Under hyperpolarization, the uptakes of Ca and Pb were enhanced and the Michaelis-Menten component prevailed. Both Ca and Pb uptakes were inhibited by N-ethyl-maleimide to the same extent. These results indicate that Pb and Ca share the same permeability pathway in human erythrocytes and that this transport system is electrogenic.

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