scholarly journals NOTE ON THE VARIATION WITH TEMPERATURE OF THE RELATIVE RATES OF HYDROLYSIS OF GLUCOSIDES

1930 ◽  
Vol 13 (3) ◽  
pp. 317-321 ◽  
Author(s):  
Emyr Alun Moelwyn-Hughes
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Different Temperatures ◽  
Hydrolysis Of ◽  
Special Case

Attention is drawn to the necessity of taking the values of the critical increments into account when the velocity constants for reactions of any pair of glucosides are compared. The ratio of the velocity coefficients for the hydrolysis of any two glucosides, determined at the same temperature, varies with temperature except in the special case when both hydrolyses have the same critical increment. Different values given by various investigators for the same ratio are shown to be due to the fact that comparative experiments have been carried out at different temperatures with two glucosides possessing different critical increments of hydrolysis. In the light of these considerations it becomes necessary to revise certain deductions which have been drawn from the comparison of rates of hydrolysis of glucosides by acids (at fairly high temperatures) with the rates of hydrolysis of glucosides by enzymes (at relatively low temperatures).

scholarly journals On a formula for the elastic force of vapour at different temperatures

1851 ◽  
Vol 5 ◽  
pp. 738-740
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Elastic Force ◽  
French Academy ◽  
Different Temperatures ◽  
Series Of Experiments ◽  
Better Than

The author adopts as the basis of his formula the first series of experiments at high temperatures made by the French Academy, and those of Magnus at low temperatures. For the Academy’s experiments, he adopts the indications of the smaller thermometer in the steam in preference to those of the larger thermometer in the water. Of Dr. Young’s sort of formulae, he notices that of the Aca­demy and several others with exponents varying from 5 to 7. From the elasticity at freezing, as given by Magnus, compared with four of the Academy’s experiments, he shows that for the range of observation the number 6 is preferable to 5 as an exponent; but, as he states, no formula of this sort with a constant index can be found to agree with the observations throughout. The formula of Magnus he finds to agree with these observations better than any of the others; but being adapted to the air-thermo­meter, and therefore not convenient for ordinary use, he gives his own formula adapted to the mercurial thermometer, t = 500 + 225 log A / 5 - log A, t being the temp. Cent., and A the elasticity in atmospheres of 0 m .76 at zero, or 30 inches at 58° Fahr.; the temperature being given, the formula becomes log A = 5 - 1625 / 225 + t .

scholarly journals Physiological and biochemical research characteristics of plant Nicotiana tabacum, expressing genes desA or desC under different temperatures stress

2016 ◽  
Vol 14 (2) ◽  
pp. 181-186
Author(s):  
T. M. Kyrpa-Nesmiian ◽  
Y. V. Sheludko ◽  
M. V. Kuchuk
Keyword(s):  
Gene Expression ◽  
Nicotiana Tabacum ◽  
High Temperatures ◽  
Low Temperatures ◽  
High Temperature Stress ◽  
Reporter Protein ◽  
Acyl Lipid ◽  
Different Temperatures ◽  
Biochemical Research ◽  
Physiological And Biochemical

Aim. For modifying of the plant organisms with genetic engineering techniques to produce genus stress resistant low temperatures or frosts it is necessary to check their physiological characteristics at high temperatures stress. Methods. In this study we used Nicotiana tabacum plants, expressing of cyanobacterial acyl-lipid desaturases genes (desA or desC), plants were tested for the level of malondialdehyde accumulation and gene expression by the reporter protein thermostable lichenase after exposure to thermal stress. Results. We discovered the reduced malondialdehyde accumulation in plants and increased expression desaturases genes after cold stress and high temperature stress. Conclusions. Cyanobacterial desaturases gene expression in Nicotiana tabacum plants did not increase their sensitivity to the high temperatures stress.Keywords: acyl-lipid desaturases, malondialdehyde, thermostable lichenase

The effect of oxygen in diamond deposition by microwave plasma enhanced chemical vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2305-2312 ◽  
Author(s):  
Y. Liou ◽  
A. Inspektor ◽  
R. Weimer ◽  
D. Knight ◽  
R. Messier
Keyword(s):  
Chemical Vapor Deposition ◽  
High Temperatures ◽  
Vapor Deposition ◽  
Low Temperatures ◽  
Film Growth ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Different Temperatures ◽  
Deposited Films

High quality diamond thin films were deposited on different substrates at temperatures from 300 to 1000 °C by the microwave plasma enhanced chemical vapor deposition (MPCVD) system. The quality of deposited diamond films was improved by adding oxygen in the gas mixtures. Different ratios of methane to oxygen concentration in hydrogen at different temperatures have been studied. At high temperatures (800–1000 °C), the addition of oxygen will not only enhance the growth rate of deposited films but also extend the region of diamond formation. At low temperatures (<500 °C), the oxygen plays an important role in diamond film growth by preferentially etching the non-diamond carbon. Without the addition of oxygen, the films deposited at high temperatures (>900 °C) were either graphitic or diamond containing a large amount of graphitic or amorphous carbon and at low temperatures (<500 °C) were white, soot-like coatings which were easily scraped off. The quality of the deposited films was characterized by Raman spectroscopy and scanning electron microscopy.

An Investigation of the Reaction Hot-Pressing Synthesis of MoSi2/Ti3SiC2/Al Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1364-1367
Author(s):  
Jin Yong Zhang ◽  
Zheng Yi Fu ◽  
Wei Min Wang
Keyword(s):  
Electrical Conductivity ◽  
High Temperatures ◽  
Powder Mixture ◽  
Hot Pressing ◽  
Low Temperatures ◽  
Creep Resistance ◽  
Linear Change ◽  
Different Temperatures ◽  
Al Powder ◽  
Nonlinear Change

MoSi2 is one of the few intermetallics to have potential for further systems. However, the use of MoSi2 has been hindered due to the brittle nature of the material at low temperatures, inadequate creep resistance at high temperatures, accelerated (pest) oxidation at temperatures between 450~ 550°C. In this investigation Mo(Al,Si2)/Ti3SiC2 composites has been prepared by reaction hot-pressing from Mo, Si, SiC, Ti, Al powder mixture under different temperatures. XRD results show that the main products are Mo(Si,Al)2 and Ti3SiC2. Part of TiC and SiC also appeared at low treating temperature. With the treating temperature increasing SiC disappeared. No evidence show lattice change of Mo(Si,Al)2. It must be the results of sufficient Al added. The electrical conductivity properties were also investigated. Samples treating under different temperatures showed different changes. Samples under high treating temperature showed a near linear change ranging from 27~800°C and Samples under low treating temperature showed a nonlinear change.

scholarly journals Temperature characteristics of peptidase in chironomid larvae, potential fish prey, at various pH values

2018 ◽  
Vol 26 (3) ◽  
pp. 201-205
Author(s):  
V. V. Kuz’mina ◽  
E. Y. Chornaya ◽  
E. G. Skvortsova ◽  
E. A. Kulivatskaya ◽  
V. A. Sheptitskiy
Keyword(s):  
Temperature Dependence ◽  
High Temperatures ◽  
Juvenile Fish ◽  
The Body ◽  
Ecological Groups ◽  
Fish Prey ◽  
Chironomid Larvae ◽  
Temperature Characteristics ◽  
Different Temperatures ◽  
Hydrolysis Of

The temperature dependence of casein- and hemoglobinlytic peptidases functioning in the whole organism of chironomid larvae Chironomus plumosus, food objects of adult benthophages and juvenile fish of various ecological groups, was studied within the temperature range of 0–70 ºС at different рН values (3.0, 5.0 and 7.4). The method of mixed samples was used to determine the activity and characteristics of enzymes. Homogenates of previously crushed and carefully mixed dozens of larvae were used as enzymatically active preparations. Activity of peptidases was assayed by the increase in tyrosine concentration using the Folin-Ciocalteu reagent. It is shown that the activity of peptidases that function in the tissues of chironomid larvae depends to a considerable extent on temperature and рН, but the pH has a smaller effect on the activity and the temperature dependence of casein- and hemoglobin-lytic peptidases than temperature. The temperature optimum of the studied peptidases of chironomid larvae corresponds to 40 ºС. The Q10 values in the zone of vital temperatures are slightly changed. They are, as a rule, increased in the zone of 30–40 ºС, and are sharply decreased in the zone of high temperatures. The values of activation energy of the process of hydrolysis of casein and hemoglobin in the zone of low and high temperatures are different. The Еact values of the process of hydrolysis of casein and hemoglobin at a temperature not exceeding 20 ºС are usually below those in the zone of higher temperatures (except for hemoglobin-lytic peptidases at pH 5.0). The data obtained indicate a significant effect of pH not only on the activity, but also on the temperature characteristics of peptidases that function in the body of chironomid larvae. Differences in the characteristics of casein- and hemoglobin-lytic peptidases in chironomid larvae at different temperatures and pH can influence the digestion in benthophages and fry of all fish species.

Quantitative Observations in Dislocation Mechanisms in Gamma TiAl

1994 ◽  
Vol 364 ◽  
Author(s):  
B. Viguier ◽  
M. Cieslar ◽  
K. J. Hemker ◽  
J. L. Martin
Keyword(s):  
Mechanical Testing ◽  
High Temperatures ◽  
Low Temperatures ◽  
Flow Strength ◽  
Statistical Variation ◽  
Different Temperatures ◽  
Defect Densities ◽  
Lattice Friction ◽  
Good Agreement

AbstractQuantitative TEM observations have been made on a series of gamma Ti47Al51Mn2 polycrystals that were deformed at different temperatures. Special attention has been given to determining the statistical variation of defect densities that occur at the different temperatures. The results, which are in good agreement with mechanical testing [J], indicate that three different mechanisms control deformation in this alloy: lattice friction and the formation of faulted dipoles at low temperatures, the pinning of ordinary dislocations at intermediate temperatures, and the bowing and looping of dislocations at high temperatures. The anomalous flow strength of this alloy has been found to be related to the intrinsic pinning of ordinary dislocations. Details of this pinning and subsequent unzipping process, which are the basis for the new local-pinning-unzipping (LPU) models[2-4], are outlined within.

Low solubility of alumina in enstatite and uncertainties in estimated palaeogeotherms

1978 ◽  
Vol 288 (1355) ◽  
pp. 471-486 ◽  
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Alumina Content ◽  
Equilibrium Solubility ◽  
Low Solubility

Spurious kinks in estimated palaeogeotherms may result from small errors in the calibration of the geothermometers and geobarometers. New data indicate that the equilibrium solubility of alumina in enstatite is even less than shown by recent studies, and that the slopes (d T /d P ) of the isopleths of equal alumina content are steeper than hitherto believed. Consequently, pressures of equilibration estimated from current formulations of the orthopyroxene-garnet geobarometer will be too high at high temperatures (> 1200 °C) and too low at low temperatures.

scholarly journals A Comparative Electrochemical and Morphological Investigation on the Behavior of NiCr and CoCr Dental Alloys at Various Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 256
Author(s):  
Florentina Golgovici ◽  
Mariana Prodana ◽  
Florentina Gina Ionascu ◽  
Ioana Demetrescu
Keyword(s):  
Low Temperatures ◽  
Artificial Saliva ◽  
Electrochemical Stability ◽  
Morphological Investigation ◽  
Dental Alloys ◽  
Ion Release ◽  
Icp Ms ◽  
Different Temperatures ◽  
Good Concordance ◽  
Increasing Temperature

The purpose of our study is to compare the behavior of two reprocessed dental alloys (NiCr and CoCr) at different temperatures considering the idea that food and drinks in the oral cavity create various compositions at different pH levels; the novelty is the investigation of temperature effect on corrosion parameters and ion release of dental alloys. Electrochemical stability was studied together with morphology, elemental composition and ions release determination. The results obtained are in good concordance: electrochemistry studies reveal that the corrosion rate is increasing by increasing the temperature. From SEM coupled with EDS, the oxide film formed on the surface of the alloys is stable at low temperatures and a trend to break after 310K. ICP-MS results evidence that in accordance with increasing temperature, the quantities of ions released from the alloys immersed in artificial saliva also increase, though they still remain small, less than 20 ppm.

scholarly journals Environmental temperature during early life affects the personality of mosquitofish in adulthood

2021 ◽  
Author(s):  
Haifeng Li ◽  
Xinyu ZHang ◽  
Yi Wu ◽  
Feng ZHang ◽  
CHunlin Li
Keyword(s):  
Body Length ◽  
High Temperatures ◽  
Low Temperatures ◽  
Early Life ◽  
Environmental Temperature ◽  
Phenotypic Trait ◽  
Behavioral Syndrome ◽  
Growing Up ◽  
Female Fish ◽  
Behavioral Traits

Abstract Personality has been observed in a variety of animal taxa with important implications in ecology and evolution. Exploring the influence of environmental temperature during early life on personality could help to understand the ontogeny of this phenotypic trait in animals. In this study, we reared newborn mosquitofish Gambusia affinis at high (30°C) and low (25°C) water temperatures and measured their shyness and exploration upon sexual maturity. We tested the repeatability of each behavioral trait; the correlation between them; and the effects of rearing temperature, sex, and body length on the behaviors. When growing up at low temperatures, female fish exhibited repeatability in shyness and exploration, and males exhibited marginal repeatability in shyness. However, neither of the 2 behaviors were repeatable when the fish were reared at high temperatures. There was a negative correlation between shyness and exploration, indicating that the 2 behaviors comprise a behavioral syndrome in this species. Mosquitofish reared at high temperatures were more explorative than those reared at low temperatures, while there was no difference in shyness between the 2 treatments. Body length and sex had no significant effects on the average values of the 2 behaviors. The results indicate that environmental temperature during early life could shape the personality of mosquitofish and modify the average of the behavioral traits. These findings might provide insights to understand the ontogeny of animal personality and how changes in environmental temperature influence animal dispersal by shaping their personality.

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