THE EFFECT OF ELECTRICAL STIMULATION AT LOW TEMPERATURES ON THE LARVAE OF PHOCANEMA DECIPIENS

1961 ◽  
Vol 39 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Clare Bradley
Keyword(s):  
Electrical Stimulation ◽  
Low Temperature ◽  
Low Temperatures ◽  
Room Temperature ◽  
Morphological Changes ◽  
Neuromuscular System ◽  
Anodal Stimulation ◽  
Rhythmical Activity ◽  
Cathodal Stimulation

Observations were made on the effect of low temperatures (down to 0° C) on the response of Phocanema to external polarizing stimuli. The response to anodal stimulation (contraction) was not affected by a fall in temperature. The response to a cathodal stimulus varied with the temperature, and whereas at room temperature the response was a relaxation, at low temperatures it was either a contraction or it was blocked altogether. Storage of the worm at low temperature for several hours had a similar effect. In some cases spontaneous rhythmical activity ceased as the temperature fell; this effect was shown to be independent of the effect of low temperature on the response to cathodal stimulation. No associated morphological changes in the neuromuscular system were observed.

scholarly journals The behaviour of visual purple at low temperature

1941 ◽  
Vol 179 (977) ◽  
pp. 151-159 ◽  
Keyword(s):  
Aqueous Solution ◽  
Low Temperature ◽  
Low Temperatures ◽  
Room Temperature ◽  
Absorption Curve ◽  
Quantum Yields

Visual purple is soluble and stable in a mixture of glycerol and water (3:1). At room temperature the spectrum of such a solution is identical with that of the aqueous solution. At — 73° C the peak of the absorption curve is higher and narrower than at room temperature, and it is shifted towards longer waves. The product of photodecomposition at — 73° C has a spectrum in ­ dependent of pH and is at low temperatures thermostable and photostable, but at room temperature it decomposes therm ally to indicator yellow. The primary product appears to be identical with transient orange. The quantum yields of the photoreaction at low and at room temperature are of the same order.

Compressive Plasticity of Zr-Based Bulk Metallic Glass at Low Temperature

2012 ◽  
Vol 443-444 ◽  
pp. 583-586
Author(s):  
Ya Juan Sun ◽  
Ri Ga Wu ◽  
Hong Jing Wang
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Low Temperatures ◽  
Room Temperature ◽  
Shear Bands ◽  
Strain Curve ◽  
Testing Temperature ◽  
Stress Strain Curve

The mechanical properties of a new Zr-based bulk metallic glass at low temperatures were investigated. The results indicate that the fracture strength increases significantly (4.9%) and the global plasticity increases somewhat when testing temperature is lowered to 123K. The stress-strain curve of the sample deformed exhibits more serrations and smaller stress drop due to formation of more shear bands at low temperature than at room temperature.

scholarly journals THE INFLUENCE OF TEMPERATURE ON THE ACTION OF STRYCHNIN IN FROGS

1913 ◽  
Vol 18 (3) ◽  
pp. 300-309 ◽  
Author(s):  
Thomas Stotesbury Githens
Keyword(s):  
Low Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Room Temperature ◽  
Drug Action ◽  
The State ◽  
Great Caution ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

In order to establish the influence of temperature upon the effect of varying doses of strychnin injected into frogs, the animals must be kept under observation for several days and at various definite degrees of temperature. Statements that the animal was kept "cold," "at room temperature," or "warm" are insufficient. With a certain dose tetanus may result constantly at 30° C. yet never appear at 21° C., and either of these temperatures might be described as warm, when compared to a room temperature of 15° C. Furthermore an animal may apparently fail to respond in the cold to an injection of certain doses of strychnin and yet be found in tetanic convulsions the next day. That an animal may have late, long lasting, or strong tetanus while kept at such a low temperature as 5° C. after an injection of a dose of strychnin smaller than 0.01 of a milligram per frog emphasizes the fact that great caution must be exercised in formulating laws as to the influence of temperature on drug action. The main results of this investigation may be summarized as follows: Doses of strychnin amounting to 0.0006 of a milligram per gram of frog will cause tetanus at all temperatures between 5° C. and 30° C., although at low temperatures the tetanus may appear late. A dose of 0.0003 of a milligram per gram of frog will frequently produce tetanus at 5° C. as well as at 30° or 27° C., but may nevertheless fail to produce any reaction at such an intermediary temperature as 21° C. Smaller doses, 0.0002 of a milligram per gram, will cause tetanus in the cold but not at high temperatures. It may be stated in general that in frogs kept at low temperatures the tetanic state sets in later, continues longer, and each tetanic attack is of longer duration, while in the interval between the attacks the state of tonus is higher and the animals are more irritable than when they are kept at higher temperatures.

INVESTIGATIONS OF PERMEABILITY, DIAPAUSE, AND HATCHING IN THE EGGS OF THE MOSQUITO AEDES HEXODONTUS DYAR

1958 ◽  
Vol 36 (4) ◽  
pp. 541-554 ◽  
Author(s):  
W. E. Beckel
Keyword(s):  
Low Temperature ◽  
Sodium Hypochlorite ◽  
Water Loss ◽  
Low Temperatures ◽  
Room Temperature ◽  
Early Embryo ◽  
Adult Mosquito ◽  
Egg Cell ◽  
Distilled Water ◽  
Exposure To Cold

Methods for collection in the laboratory of many thousands of eggs from field-collected, blood-fed females are described. Also a way of separating fertile from infertile eggs is outlined. When the eggs are laid they are white but begin to darken within one-half hour. The darkening did not occur when the egg cell or early embryo was killed.Two changes in permeability in the prediapause stage of the eggs of Aedcs hexodontus were observed. The first took place as the chorion changed from white to black. The egg lost and gained water easily when first laid but resisted water loss and uptake as the chorion darkened. However, a complete waterproofing did not result. With the formation of the transparent cuticle a further change in permeability occurred. The egg lost hardly any water even when exposed to extreme desiccation and what little water was lost was regained very slowly. However, the cuticle, with the chorion removed in sodium hypochlorite, was quite permeable. The impermeability of the chorion and cuticle combination must result from the bonding between the two and this bonding must be disrupted by the dechorionation.To study the obligate diapause that occurs in the late embryogeny of the mosquito egg the effect of making water available to the embryo, of light, and of low temperature was studied. Diapause was not broken when water was available to the embryo, nor did alternate periods of light and dark at room temperature or at lower temperatures disrupt the diapause. To test the influence of cold the temperature of 1° and −3 °C. were used to simulate the temperatures in the field. The low temperatures were found to terminate the diapause but the numbers of eggs hatching did not steadily increase with an increase in the time of exposure to cold. No clue has as yet been discovered to explain these results. A hatching infusion of decaying adult mosquito bodies in distilled water was found to give more hatching than did distilled water alone. The mechanism of the hatching stimulus is not known.

Primary Defects in n-Type Irradiated Germanium: A First-Principles Investigation

2007 ◽  
Vol 131-133 ◽  
pp. 253-258 ◽  
Author(s):  
A. Carvalho ◽  
R. Jones ◽  
C. Janke ◽  
Sven Öberg ◽  
Patrick R. Briddon
Keyword(s):  
Low Temperature ◽  
Point Defects ◽  
Electron Irradiation ◽  
First Principles ◽  
Low Temperatures ◽  
Damage Evolution ◽  
Room Temperature ◽  
Temperature Electron ◽  
Conductivity Loss

The properties of point defects introduced by low temperature electron irradiation of germanium are investigated by first-principles modeling. Close Frenkel pairs, including the metastable fourfold coordinated defect, are modelled and their stability is discussed. It is found that damage evolution upon annealing below room temperature can be consistently explained with the formation of correlated interstitial-vacancy pairs if the charge-dependent properties of the vacancy and self-interstitial are taken into account. We propose that Frenkel pairs can trap up to two electrons and are responsible for conductivity loss in n-type Ge at low temperatures.

Heat Conductivity of Rubber at Low Temperatures

1940 ◽  
Vol 13 (4) ◽  
pp. 830-830
Author(s):  
Adolf Schallamach
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Temperature Region ◽  
Heat Conductivity ◽  
Low Temperatures ◽  
Room Temperature ◽  
Tire Rubber ◽  
Order Of Magnitude ◽  
Temperature Work

Abstract While examining the possibilities of applying rubber in low temperature work, we were hampered by the lack of available data on its physical properties at low temperatures. We were aware of the difficulties to be expected in making accurate measurements in that temperature region, and this applied especially to the heat conductivity, in which we were particularly interested. To obtain at least an estimate of the order of magnitude, we carried out some measurements of the heat conductivity of commercial rubber (North British tire rubber) at room temperature and at the temperature of liquid air.

Low-Temperature Growth of Thin Films of A12O3 with Trimethylaluminum and Hydrogen Peroxide

1991 ◽  
Vol 222 ◽  
Author(s):  
J. F. Fan ◽  
K. Sugioka ◽  
K. Toyoda
Keyword(s):  
Thin Films ◽  
Hydrogen Peroxide ◽  
Low Temperature ◽  
Chemical Reaction ◽  
Low Temperatures ◽  
Arbitrary Shape ◽  
Room Temperature ◽  
Surface Chemical ◽  
Surface Chemical Reaction ◽  
Temperature Growth

ABSTRACTThin films of A12O3 were prepared by sequential surface chemical reaction of trimethylaluminum and hydrogen peroxide at low temperatures. It has been found that hydrogen peroxide reacts very easily with trimethylaluminum, resulting in growth of A12O3 at the temperature as low as the room temperature. Another favorable feature of the technique is that the growth of excellent A12O3 occurs identically wherever the reactants reach, making it possible to completely coat the surface of the sample with arbitrary shape.

Light-Weight Mechanism of Pressure Strengthening of Cryogenic Vessels From Austenitic Stainless Steel

2018 ◽  
Author(s):  
Qunjie Lu ◽  
Gai Huang ◽  
Yingzhe Wu ◽  
Huiming Ding ◽  
Jinyang Zheng
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Low Temperatures ◽  
Storage Tank ◽  
Room Temperature ◽  
Light Weight ◽  
Strength Enhancement ◽  
Leading Role ◽  
Strength Increment

Pressure Strengthening (PS) is a technology widely used to increase the allowable stress and thus reduce the weight of Austenitic Stainless Steel (ASS) cryogenic vessels. Pre-strain and low temperature are two important factors enhancing the strength. However, standards such as EN 13458-2, ASME VIII-I, AS 1210 and ISO 21009-1, state that the strengthening is based on work hardening of ASS, while the effect of low temperature was ignored or not mentioned. Therefore, in this work, the influence of low temperature on cryogenic mechanical properties of S30408 stainless steel and its welded joints were studied firstly, then a numerical analysis on the influence of pressure strengthening of a large transportable cryogenic storage tank was conducted. Finally, after the technical significance of PS was discussed, a new understanding was proposed. Conclusions come that: (a) At room temperature, the strength of ASS can be increased by pre-strain; while at −196 °C, the strengthening of low temperature plays a leading role (2/3 or more) for strength increment; (b) The purpose of PS technique is to stabilize the dimensions of the internal vessel. It is unnecessary to consider insufficient strengthening or over strengthening at different location because the strength enhancement is mainly due to low temperatures.

scholarly journals MICROSPECTROPHOTOMETRY OF CYTOCHROMES IN THE SINGLE CELL AT ROOM AND LIQUID NITROGEN TEMPERATURES

1965 ◽  
Vol 26 (3) ◽  
pp. 741-746 ◽  
Author(s):  
B. Thorell ◽  
B. Chance ◽  
V. Legallais
Keyword(s):  
Low Temperature ◽  
Single Cell ◽  
Liquid Nitrogen ◽  
Low Temperatures ◽  
Room Temperature ◽  
Single Cells ◽  
Visible Region ◽  
Absorption Bands ◽  
Preliminary Results ◽  
Favorable Conditions

By increasing further the sensitivity of microspectrophotometry, it is now possible to measure, under favorable conditions, the smaller absorption bands of the respiratory pigments of single cells in the visible region of the spectrum. A considerable aid in the distinction between cytochromes is afforded by liquid nitrogen microspectrophotometry. Under favorable conditions, the height of the peaks is increased over 8-fold at low temperatures. In diploid yeast, characteristically sharpened components not resolvable at room temperature are observed at low temperature; and in pentaploid yeast, a hitherto unrecognized pigment is observed at 583 mµ. These preliminary results indicate the feasibility and the value of low temperature microspectrophotometry of biological materials.

scholarly journals Morphological Features and Cold-Response Gene Expression in Mesophilic Bacillus cereus Group and Psychrotolerant Bacillus cereus Group under Low Temperature

2021 ◽  
Vol 9 (6) ◽  
pp. 1255
Author(s):  
Kyung-Min Park ◽  
Hyun-Jung Kim ◽  
Min-Sun Kim ◽  
Minseon Koo
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Low Temperature ◽  
Bacillus Cereus ◽  
Low Temperatures ◽  
Fatty Acid Biosynthesis ◽  
Morphological Changes ◽  
Growth Strategies ◽  
Acid Biosynthesis ◽  
Bacillus Cereus Group

At low temperatures, psychrotolerant B. cereus group strains exhibit a higher growth rate than mesophilic strains do. However, the different survival responses of the psychrotolerant strain (BCG34) and the mesophilic strain (BCGT) at low temperatures are unclear. We investigated the morphological and genomic features of BCGT and BCG34 to characterize their growth strategies at low temperatures. At low temperatures, morphological changes were observed only in BCGT. These morphological changes included the elongation of rod-shaped cells, whereas the cell shape in BCG34 was unchanged at the low temperature. A transcriptomic analysis revealed that both species exhibited different growth-related traits during low-temperature growth. The BCGT strain induces fatty acid biosynthesis, sulfur assimilation, and methionine and cysteine biosynthesis as a survival mechanism in cold systems. Increases in energy metabolism and fatty acid biosynthesis in the mesophilic B. cereus group strain might explain its ability to grow at low temperatures. Several pathways involved in carbohydrate mechanisms were downregulated to conserve the energy required for growth. Peptidoglycan biosynthesis was upregulated, implying that a change of gene expression in both RNA-Seq and RT-qPCR contributed to sustaining its growth and rod shape at low temperatures. These results improve our understanding of the growth response of the B. cereus group, including psychrotolerant B. cereus group strains, at low temperatures and provide information for improving bacterial inhibition strategies in the food industry.

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