scholarly journals THE RELATIONSHIP BETWEEN CHEMICAL STRUCTURE AND THE RESPONSE OF BLOWFLIES TO TARSAL STIMULATION BY ALIPHATIC ACIDS

1947 ◽  
Vol 30 (3) ◽  
pp. 255-262 ◽  
Author(s):  
L. E. Chadwick ◽  
V. G. Dethier
Keyword(s):  
Chemical Structure ◽  
Free Acid ◽  
Mineral Acid ◽  
Hydrogen Ion ◽  
Phormia Regina ◽  
Hydrogen Ions ◽  
Degree Of Dissociation ◽  
Rate Of Increase ◽  
Proboscis Extension ◽  
The Relationship

Using the technique of proboscis extension in antennectomized-labellectomized flies, the rejection thresholds of Phormia regina for 18 fatty acids and one mineral acid have been determined. The conclusions reached on the basis of these data may be summarized in the following terms: Tarsal stimulation by acids involves the summation of components from at least two sources. Of these the hydrogen ion is the most important. The other major factor is probably the anion rather than the undissociated acid. The stimulating power of the anions (or free acid molecules) increases with increasing chain length in both the mono- and dicarboxylic series, but the rate of increase decreases as the series is ascended. Acids containing 6 or more carbon atoms are not sufficiently soluble in 0.1 M sucrose to reach the threshold of rejection. Substitution of —H in the acyl grouping by —Cl, —OH, =O or —COOH, the presence of a C=C bond, or a shift from the trans- to the cis- configuration all diminish the effectiveness of the anion (or free acid). But since such alterations also augment the degree of dissociation and consequently the concentration of hydrogen ions, the net result is ordinarily a lowering of threshold in terms of the molar concentration required for rejection.

scholarly journals A STABLE HEMOLYSIN-LEUCOCIDIN AND ITS CRYSTAL-LINE DERIVATIVE ISOLATED FROM BETA HEMOLYTIC STREPTOCOCCI

1938 ◽  
Vol 67 (4) ◽  
pp. 643-657 ◽  
Author(s):  
E. J. Czarnetzky ◽  
Isabel M. Morgan ◽  
Stuart Mudd
Keyword(s):  
Molecular Weight ◽  
Methylene Blue ◽  
Sodium Salt ◽  
Blood Cells ◽  
Chemical Structure ◽  
Free Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
High Degree

1. A chemically pure hemolysin-leucocidin has been isolated from ß hemolytic streptococci, but not from other species of bacteria studied. 2. It does not give rise to antibodies, but precipitates immune sera against hemolytic streptococci, and is therefore a hapten. 3. A highly purified sample of S. H. up to a dilution of 1:128,000 hemolyzes red blood cells. Its hemolytic activity is not specifically neutralized by antiserum versus ß hemolytic streptococci. It is leucocidic in that it inhibits the reduction of methylene blue by leucocytes. 4. The hemolysin-leucocidin is stable to oxygen, to heat and to moderate changes in hydrogen ion concentration. Its chemical structure has been determined in part. Its molecular weight is 2260. 5. A crystalline derivative has been isolated as the sodium salt from the hemolysin-leucocidin. As the free acid it has a molecular weight of 720. Its hemolytic and leucocidic activity parallels that of S. H., although it is not serologically active. It possesses a high degree of toxicity for mice and rabbits.

Relation Between Hydrogen Ion Secretion and Oxygen Consumption by Ex Vivo Isolated Canine Stomach, Perfused with Homologous Blood

1972 ◽  
Vol 50 (10) ◽  
pp. 955-961 ◽  
Author(s):  
K. Kowalewski ◽  
A. Kolodej
Keyword(s):  
Oxygen Consumption ◽  
Linear Correlation ◽  
Biochemical Analysis ◽  
Ex Vivo ◽  
Hydrogen Ion ◽  
Hydrogen Ions ◽  
Homologous Blood ◽  
Method Of Least Squares ◽  
Ion Secretion ◽  
The Relationship

The relationship between oxygen consumption and acid secretion was studied in 28 totally isolated ex vivo canine stomachs, perfused extracorporeally with homologous blood. Two hundred six 30-min samples of gastric juice and blood were collected for biochemical analysis. Paired values of HCl (microequivalents per minute) and O2 consumption (micromoles per minute) were then analyzed by the method of least squares, using a computer. Linear correlation was calculated between these two values. The correlation coefficient was 0.9518 and the slope of the line was 0.512. The ratio of hydrogen ions produced to oxygen molecules consumed was 1.18 ± 0.53. The range of titratable H+ found in this study was from 0 to 833 μequiv/min and the range of O2 consumed was from 18 to 442 μmol/min.

PSVI-8 Meta-regression Analysis to Determine the Relationship Between Growing Pig Body Weight and Variation

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 218-219
Author(s):  
Andres Fernando T Russi ◽  
Mike D Tokach ◽  
Jason C Woodworth ◽  
Joel M DeRouchey ◽  
Robert D Goodband ◽  
...  
Keyword(s):  
Body Weight ◽  
Regression Analysis ◽  
Sample Size ◽  
Polynomial Regression ◽  
Data Sets ◽  
Regression Equations ◽  
Prediction Equations ◽  
Data Set ◽  
Rate Of Increase ◽  
The Relationship

Abstract The swine industry has been constantly evolving to select animals with improved performance traits and to minimize variation in body weight (BW) in order to meet packer specifications. Therefore, understanding variation presents an opportunity for producers to find strategies that could help reduce, manage, or deal with variation of pigs in a barn. A systematic review and meta-analysis was conducted by collecting data from multiple studies and available data sets in order to develop prediction equations for coefficient of variation (CV) and standard deviation (SD) as a function of BW. Information regarding BW variation from 16 papers was recorded to provide approximately 204 data points. Together, these data included 117,268 individually weighed pigs with a sample size that ranged from 104 to 4,108 pigs. A random-effects model with study used as a random effect was developed. Observations were weighted using sample size as an estimate for precision on the analysis, where larger data sets accounted for increased accuracy in the model. Regression equations were developed using the nlme package of R to determine the relationship between BW and its variation. Polynomial regression analysis was conducted separately for each variation measurement. When CV was reported in the data set, SD was calculated and vice versa. The resulting prediction equations were: CV (%) = 20.04 – 0.135 × (BW) + 0.00043 × (BW)2, R2=0.79; SD = 0.41 + 0.150 × (BW) - 0.00041 × (BW)2, R2 = 0.95. These equations suggest that there is evidence for a decreasing quadratic relationship between mean CV of a population and BW of pigs whereby the rate of decrease is smaller as mean pig BW increases from birth to market. Conversely, the rate of increase of SD of a population of pigs is smaller as mean pig BW increases from birth to market.

Assessment of the Structure of Polysilicate Binding with Added Glycerol

2020 ◽  
Vol 987 ◽  
pp. 15-19 ◽  
Author(s):  
Valentina I. Loganina ◽  
Yerkebulan Bisengalievich Mazhitov ◽  
Yuri Petrovich Skachkov
Keyword(s):  
Ir Spectroscopy ◽  
Liquid Glass ◽  
Chemical Structure ◽  
Partial Replacement ◽  
Potassium Ions ◽  
Hydrogen Ions

The article presents the results of the study of the properties of the sol of silicate paint. The chemical structure of the polysilicate solutions obtained with the addition of glycerol was studied by IR spectroscopy. It is shown, that the interaction of potassium liquid glass and glycerol is weak and due to the partial replacement of hydrogen ions by potassium ions.

Hydrogen Ion Beam Processing of Single Crystal Diamond Chips

1994 ◽  
Vol 354 ◽  
Author(s):  
Shuji Kiyohara ◽  
Iwao Miyamoto
Keyword(s):  
Surface Roughness ◽  
Single Crystal ◽  
Incidence Angle ◽  
Ion Beam ◽  
Etching Rate ◽  
Hydrogen Ion ◽  
Hydrogen Ions ◽  
Ion Beam Etching ◽  
Single Crystal Diamond ◽  
Before And After

AbstractIn order to apply ion beam etching with hydrogen ions to the ultra-precision processing of diamond tools, hydrogen ion beam etching characteristics of single crystal diamond chips with (100) face were investigated. The etching rate of diamond for 500 eV and 1000 eV hydrogen ions increases with the increase of the ion incidence angle, and eventually reaches a maximum at the ion incidence angle of approximately 50°, then may decrease with the increase of the ion incidence angle. The dependence of the etching rate on the ion incidence angle of hydrogen ions is fairly similar to that obtained with argon ions. Furthermore, the surface roughness of diamond chips before and after hydrogen ion beam etching was evaluated using an atomic force microscope. Consequently, the surface roughness after hydrogen ion beam etching decreases with the increase of the ion incidence angle within range of the ion incidence angle of 60°.

Thermal Expansion and Laser Trim Stability of Ruthenium Based Thick Film Resistors on Alumina and on Multilayer Dielectric

1982 ◽  
Vol 1 (1) ◽  
pp. 24-27 ◽  
Author(s):  
I. Taitl
Keyword(s):  
Thermal Expansion ◽  
Thick Film ◽  
Chemical Structure ◽  
Coefficient Of Thermal Expansion ◽  
Ruthenium Dioxide ◽  
Theoretical Conclusion ◽  
Film Resistor ◽  
Thick Film Resistor ◽  
The Relationship ◽  
Multilayer Dielectric

Fired resistors exhibit variations which are minimised by abrasive and laser trimming. The latter may cause unstable behaviour which is further aggravated by thermal shock. The chemical structure of a thick film resistor is analysed with respect to mechanical stress, and the theoretical conclusion that the coefficient of thermal expansion of the resistor should be equal to or smaller than that of the substrate is verified experimentally. The thermal behaviour of ruthenium dioxide is examined and a range of CTE values are determined for materials of varying chemical composition. The relationship between CTE and post laser trimming stability is demonstrated on four thick film resistors which differ in thermal expansion. It is pointed out that formulations with high metallic content can absorb tensile stress by elastic deformation, thus minimising the formation or propagation of laser induced cracks.

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