scholarly journals The kinetics of hæmoglobin. III.—The velocity with which oxygen combines with reduced hæmoglobin

1925 ◽  
Vol 107 (744) ◽  
pp. 654-683 ◽  
Keyword(s):  
Unit Volume ◽  
Salt Content ◽  
Hemoglobin Concentration ◽  
Spectroscopic Observation ◽  
Mixed Solution ◽  
Dissociation Curve ◽  
Reaction Velocity ◽  
Velocity Constant ◽  
Mixing Chamber ◽  
Kinetics Of

The velocity with which oxygen dissociates from its combination with hæmoglobin, and the factors upon which the velocity-constant of this reaction depends, have already been investigated by us in some detail in the second of the present series of papers (1). Since then we have been engaged in a similar inquiry into the velocity of the reverse reaction, i. e ., the combination of oxygen with reduced hæmoglobin. The scope of the investigation, which we are now about to describe, was as follows:— (α) To determine the order of the reaction between oxygen and hæmoglobin (see p. 663). (β) To compare the value of the velocity-constant for the combination of O 2 + Hb ______________________________________________________ the velocity-constant for the dissociation of O 2 .Hb→ with the value of the equilibrium-constant of the reaction as determined from the dissociation curve. (γ) To study the effect of (i) p H (ii) temperature, (iii) light, and (iv) salt content upon the velocity of the reaction between O 2 and hæmoglobin. The general methods adopted were similar to those used in studying the rate of dissociation of oxyhæmoglobin. One solution (I) consisted of water containing a considerable quantity of oxygen in solution, whereas the other solution (II) consisted of reduced hæmoglobin. These were driven by separate jets into the mixing chamber of the reaction velocity apparatus (2 and 3), and after mixing travelled steadily with known velocity down the observation tube. Spectroscopic observation of the ratio of oxyhæmoglobin to reduced hemoglobin concentration at various points of the tube, together with a knowledge of the rate of linear flow and of the total amount of (i) oxygen and (ii) hæmoglobin in unit volume of the mixed solution, gave us all the data required for the measurement of the velocity of the reaction.

scholarly journals THE KINETICS OF EXOSMOSIS OF WATER FROM LIVING CELLS

1927 ◽  
Vol 10 (5) ◽  
pp. 659-664 ◽  
Author(s):  
Morton McCutcheon ◽  
Baldwin Lucke
Keyword(s):  
Osmotic Pressure ◽  
Salt Concentration ◽  
Driving Force ◽  
Temperature Characteristic ◽  
Living Cells ◽  
Velocity Constant ◽  
Osmotic Equilibrium ◽  
Kinetics Of

1. The rate of exosmosis of water was studied in unfertilized Arbacia eggs, in order to bring out possible differences between the kinetics of exosmosis and endosmosis. 2. Exosmosis, like endosmosis, is found to follow the equation See PDF for Equation, in which a is the total volume of water that will leave the cell before osmotic equilibrium is attained, x is the volume that has already left the cell at time t, and k is the velocity constant. 3. The velocity constants of the two processes are equal, provided the salt concentration of the medium is the same. 4. The temperature characteristic of exosmosis, as of endomosis, is high. 5. It is concluded that the kinetics of exosmosis and endosmosis of water in these cells are identical, the only difference in the processes being in the direction of the driving force of osmotic pressure.

scholarly journals Diffusion and chemical reaction velocity as joint factors in determining the rate of uptake of oxygen and carbon monoxide by the red blood corpuscle

1932 ◽  
Vol 111 (769) ◽  
pp. 1-36 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Cross Sections ◽  
The Other ◽  
Blood Corpuscle ◽  
Reaction Velocity ◽  
Two Fluids ◽  
Mixing Chamber ◽  
Haemoglobin Solution ◽  
Moving Fluid

In a paper on this subject published four years age, Hartridge and Roughton (1927) described some preliminary experiments upon the rate of uptake of oxygen and carbon monoxide by the red blood corpuscle, the observations being made by means of their reaction velocity technique (Hartridge and Roughton, 1922–1927). The general principles of the method were as follows. Through one lead of the apparatus a suspension of reduced corpuscles in saline was forces into the mixing chamber, whilst through the other lead was forced a solution of oxygen (or carbon monoxide) in saline. The two fluids mixed in the mixing chamber within 0·001 second or less and then travelled down the observation tube. Determination of the percentage of oxyhæmoglobin (or carboxyhæmoglobin) in the moving fluid at various cross sections of the observation tube was made by means of the reversion spectroscope, these measurements, together with a knowledge of the rate of flow of the fluid down the observation tube, giving the necessary data for plotting the rate of uptake of O 2 or CO by the corpuscles against time. The most interesting feature of the results was the much slower uptake of O 2 by hæmoglobin in the intact corpuscle as compared with the of O 2 by hæmoglobin in laked solution as previously recorded by Hartridge and Roughton (1925). In the corpuscle experiments the time scale had to be expressed in hundredths of a second instead of in thousandths of a second as in the hæmoglobin solution experiments ( vide fig. 2 of Hartridge and Roghton, 1927). Confirmatory results by somewhat different technique have been obtained lately by Dirken and Mook (1931). These will be referred to again later.

THE KINETICS OF CUPRENE GROWTH

1950 ◽  
Vol 28b (7) ◽  
pp. 358-372
Author(s):  
Cyrias Ouellet ◽  
Adrien E. Léger
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Apparent Activation Energy ◽  
Copper Catalyst ◽  
Maximum Velocity ◽  
Static System ◽  
Reaction Velocity ◽  
First Order ◽  
Kinetics Of

The kinetics of the polymerization of acetylene to cuprene on a copper catalyst between 200° and 300 °C. have been studied manometrically in a static system. The maximum velocity of the autocatalytic reaction shows a first-order dependence upon acetylene pressure. The reaction is retarded in the presence of small amounts of oxygen but accelerated by preoxidation of the catalyst. The apparent activation energy, of about 10 kcal. per mole for cuprene growth between 210° and 280 °C., changes to about 40 kcal. per mole above 280 °C. at which temperature a second reaction seems to set in. Hydrogen, carbon monoxide, or nitric oxide has no effect on the reaction velocity. Series of five successive seedings have been obtained with cuprene originally grown on cuprite, and show an effect of aging of the cuprene.

scholarly journals H. The Kinetics of Enzyme Cascade Systems General kinetics of enzyme cascades

1969 ◽  
Vol 173 (1032) ◽  
pp. 411-420 ◽  
Keyword(s):  
Product Formation ◽  
Coagulation Cascade ◽  
Lag Phase ◽  
Open Type ◽  
Reaction Velocity ◽  
Cascade Systems ◽  
Enzyme Cascade ◽  
Enzyme Cascades ◽  
Kinetics Of ◽  
Product Relation

The theory of the kinetics of enzyme cascades is developed. Two types of cascades are recognized, one in which the products are stable ( open cascades ) and another in which the products are broken down ( damped cascades ). It is shown that it is a characteristic of a cascade that the final product appears after a certain lag phase. After this lag phase, the velocity of product formation can be very rapid. It is shown that whereas open cascades will always show a complicated time–product relation, damped cascades can under certain circumstances resemble a simple enzymic reaction. Because the relation between the over-all reaction velocity in the extrinsic coagulation cascade and the concentration of any of the proenzymes in this cascade is a hyperbolic one, it is concluded that this cascade is of the damped type rather than the open type.

THE PHOTOINITIATED ADDITION OF MERCAPTANS TO OLEFINS: II. THE KINETICS OF THE ADDITION OF n-BUTYL MERCAPTAN TO 1-PENTENE

1955 ◽  
Vol 33 (5) ◽  
pp. 1034-1042 ◽  
Author(s):  
M. Onyszchuk ◽  
C. Sivertz
Keyword(s):  
Alkyl Radical ◽  
Side Reactions ◽  
Thiyl Radical ◽  
Principal Mechanism ◽  
Velocity Constant ◽  
Transfer Step ◽  
Wide Range ◽  
Detailed Kinetics ◽  
Kinetics Of

The detailed kinetics involved in the photoinitiated addition of n-butyl mercaptan to 1-pentene is presented. It has been shown that side reactions such as propagation and α-dehydrogenation are relatively negligible and the principal mechanism comprises attack by thiyl radical followed by transfer with mercaptan by the alkyl radical. The velocity constant of the attack step is estimated to be 7 × 106 and that of the transfer step 1.4 × 106 liters/mole-sec. These values together with approximate termination velocity constants are shown to explain the kinetics over a wide range of concentration.

Anionic polyacrylamide “water-in-water” emulsion prepared by dispersion polymerization in mixed salt aqueous media

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Yongli Lü ◽  
Yujun Feng ◽  
Yongfeng Zhao ◽  
Sheng Zhang ◽  
Songkuang Shu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Dispersion Polymerization ◽  
Inorganic Salt ◽  
Salt Content ◽  
Reaction System ◽  
Polymeric Materials ◽  
Water Soluble ◽  
Molar Ratio ◽  
Mixed Solution ◽  
Water Emulsion

AbstractPolyacrylamide “water-in-water” emulsion was regarded as a new generation of water-soluble polymeric materials and has attracted much attention from both academia and industry because of its environmentally-friendly character. Anionic polymeric “water-in-water” emulsions prepared by dispersion polymerization of acrylamide (AM) and sodium acrylic acid (NaAA) in mixed solution of Na2SO4 and (NH4)2SO4 are reported in this paper, and the parameters influencing polymerization and the final dispersion stability, including, N2 flow rate, chain transfer agent content, inorganic salt content, and the molar ratio of AM to NaAA were examined and opitimized. It was found that the intrinsic viscosity of resulting copolymers decreased as the N2 flow rate and CTA concentration increased, and the resultant dispersions with 27 % ∼ 28 % inorganic salt have regular particle shape, lowest particle size, better flowability and storage stability. The salt level in the reaction system would also dominate the time that the dispersion formed, and the ratio of AM to NaAA would influence the total monomers conversion and polymerization rate.

Effects of resolution on the measurement of grain ‘size’

1985 ◽  
Vol 49 (353) ◽  
pp. 539-546 ◽  
Author(s):  
R. Dearnley
Keyword(s):  
Grain Size ◽  
Image Analysis ◽  
Grain Boundary ◽  
Surface Area ◽  
Unit Volume ◽  
Fractal Dimensions ◽  
Size Analysis ◽  
Automatic Image Analysis ◽  
Fine Grained ◽  
Kinetics Of

AbstractMeasurements of fine-grained dolerites by optical automatic image analysis are used to illustrate the effects of magnification and resolution on the values obtained for grain ‘size’, grain boundary length, surface area per unit volume, and other parameters. Within the measured range of optical magnifications (× 26 to × 3571) and resolutions (1.20 × 10−3 cm to 8.50 × 10−6 cm), it is found that the values of all grain parameters estimated by chord size analysis vary with magnification. These results are interpreted in terms of the concepts of ‘fractal dimensions’ introduced by Mandelbrot (1967, 1977). For some comparative purposes the fractal relationships may be of little significance as relative changes of size, surface area, and other parameters can be expressed adequately at given magnification(s). But for many studies, for instance in kinetics of grain growth, the actual diameter or surface area per unit volume is an important dimension. The consequences are disconcerting and suggest that it may be difficult in some instances to specify the ‘true’ measurements of various characteristics of fine-grained aggregates.

Viability of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Yellow Fat Spreads as Affected by Storage Temperature

2003 ◽  
Vol 66 (4) ◽  
pp. 549-558 ◽  
Author(s):  
SARAH L. HOLLIDAY ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Salt Content ◽  
Inactivation Kinetics ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Inhibition Of Growth ◽  
Time Required ◽  
Kinetics Of

A study was conducted to characterize the survival and inactivation kinetics of a five-serotype mixture of Salmonella (6.23 to 6.55 log10 CFU per 3.5-ml or 4-g sample), a five-strain mixture of Escherichia coli O157:H7 (5.36 to 6.14 log10 CFU per 3.5-ml or 4-g sample), and a six-strain mixture of Listeria monocytogenes (5.91 to 6.18 log10 CFU per 3.5-ml or 4-g sample) inoculated into seven yellow fat spreads (one margarine, one butter-margarine blend, and five dairy and nondairy spreads and toppings) after formulation and processing and stored at 4.4, 10, and 21°C for up to 94 days. Neither Salmonella nor E. coli O157:H7 grew in any of the test products. The time required for the elimination of each pathogen depended on the product and the storage temperature. Death was more rapid at 21°C than at 4.4 or 10°C. Depending on the product, the time required for the elimination of viable cells at 21°C ranged from 5 to 7 days to >94 days for Salmonella, from 3 to 5 days to 28 to 42 days for E. coli O157:H7, and from 10 to 14 days to >94 days for L. monocytogenes. Death was most rapid in a water-continuous spray product (pH 3.66, 4.12% salt) and least rapid in a butter-margarine blend (pH 6.66, 1.88% salt). E. coli O157:H7 died more rapidly than did Salmonella or L. monocytogenes regardless of storage temperature. Salmonella survived longer in high-fat (≥61%) products than in products with lower fat contents. The inhibition of growth is attributed to factors such as acidic pH, salt content, the presence of preservatives, emulsion characteristics, and nutrient deprivation. L. monocytogenes did not grow in six of the test products, but its population increased between 42 and 63 days in a butter-margarine blend stored at 10°C and between 3 and 7 days when the blend was stored at 21°C. On the basis of the experimental parameters examined in this study, traditional margarine and spreads not containing butter are not “potentially hazardous foods” in that they do not support the growth of Salmonella, E. coli O157:H7, or L. monocytogenes.

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