Accroissement de la résistance au froid de plantules de blé avec un milieu cryoprotecteur : variation de la température et de la durée du traitement d'imprégnation. Aspects physiologiques

1982 ◽  
Vol 60 (12) ◽  
pp. 2857-2863 ◽  
Author(s):  
C. M. Gazeau
Keyword(s):  
Dimethyl Sulfoxide ◽  
Freezing Tolerance ◽  
Low Temperatures ◽  
The Other ◽  
Ice Formation ◽  
Formation Temperature ◽  
Effective Protection ◽  
Wheat Seedlings ◽  
Other Hand

Different methods of hardening wheat seedlings to withstand freezing to low temperatures were studied. The procedures involved the impregnation of the seedlings with a cryoprotective mixture of glycerol, dimethyl sulfoxide and sucrose for various times and at various temperatures. Impregnation of the seedlings with such a mixture at 20 °C for 1 day imparted an effective protection to freezing at 1 °C/min. Longer periods of impregnation did not further increase the freezing survival. On the other hand, if the impregnation was carried out at 2 °C, freezing tolerance developed only slowly for the first 3 days, but improved rapidly between the 4th and the 6th day. Longer periods of impregnation at 2 °C did not further increase freezing survival. Freezing tolerance was observed to be related to both a lowered nucleation and ice-formation temperature in the impregnated tissues.

Influence de la température et de la durée d'un traitement cryoprotecteur sur la résistance au froid de plantules de blé. Étude ultrastructurale des nucléoles des ébauches foliaires

1985 ◽  
Vol 63 (4) ◽  
pp. 663-671 ◽  
Author(s):  
Claude-Madeleine Gazeau
Keyword(s):  
Dimethyl Sulfoxide ◽  
Low Temperatures ◽  
Leaf Primordia ◽  
Distilled Water ◽  
Wheat Seedlings ◽  
Cryoprotective Agent

The nucleolus is sensitive to cold-protective media and to low temperatures. Nucleolar changes observed in the leaf primordia of wheat seedlings were related to the impregnation medium (distilled water or a mixture of glycerol, dimethyl sulfoxide, and sucrose), to the temperature (20 or 2 °C), and to the duration of the pretreatment (1 to 12 days). The cryoprotective agent generated the formation of nucleoli "with a diffuse granular zone." If the impregnation was done at 2 °C, characteristic nucleoli "with an indented aspect" occurred. The longer the duration of the impregnation and the more intense the subsequent freezing, the more important were the nucleolar changes. On rewarming the seedlings the various transformations were shown to be reversible.

Synthesis and antibacterial activity of some 1-(2-propynyl) and 1-propadienyl derivatives of 1,4-dihydro-4-oxoquinoline-3-carboxylic acids and similar heterocycles

1991 ◽  
Vol 56 (2) ◽  
pp. 439-448 ◽  
Author(s):  
Stanislav Rádl ◽  
Lenka Kovářová ◽  
Jiří Holoubek
Keyword(s):  
Antibacterial Activity ◽  
Dimethyl Sulfoxide ◽  
Carboxylic Acids ◽  
Potassium Carbonate ◽  
Potassium Hydroxide ◽  
Room Temperature ◽  
Ethyl Esters ◽  
The Other ◽  
Other Hand ◽  
Derivatives Of

N-Alkylation of IIIa, IIIb, IIId - IIIf and 9-acridanone with 3-bromopropyne in dimethyl sulfoxide in the presence of potassium carbonate yielded N-(2-propynyl) derivatives IVa - IVe and VIa, respectively. Ethyl esters IVa, IVb, and IVe were hydrolyzed to IVf - IVh, respectively. Compounds IVf, IVg, IVctreated with bases yielded N-propadienyl derivatives Va - Vc. On the other hand 2-substituted compounds IVd and IVh did not change under the same conditions. Compound VIa treated with powdered potassium hydroxide in dimethyl sulfoxide at room temperature yielded N-(1-propynyl) derivative VII.

scholarly journals Temperature and Enzyme Activity

1927 ◽  
Vol 14 (3) ◽  
pp. 723-727 ◽  
Author(s):  
John R. Baker
Keyword(s):  
Enzyme Activity ◽  
Low Temperatures ◽  
The Other ◽  
Effect Of Temperature ◽  
Crystalline Style ◽  
Other Hand

The enzyme contained in the crystalline style of Pecten is destroyed more and more rapidly as temperature increases. On the other hand, it becomes more and more active if incubated at fairly low temperatures, possibly as a result of the progressive dispersion of the protein base on which it is absorbed. A graph has been calculated showing the effect of temperature on enzyme activity when both destruction and (?) dispersion are discounted.

scholarly journals EFFECTS OF LOW-TEMPERATURE ON THE QUALITY OF TURNIP ROOTS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1127f-1127 ◽  
Author(s):  
V.I. Shattuck ◽  
Y. Kakuda ◽  
B.J. Shelp ◽  
N. Kakuda
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
The Other ◽  
Sensory Characteristics ◽  
Glucosinolate Content ◽  
Other Hand ◽  
Sugar Levels

The influence of low-temperature on the starch, sugar and glucosinolate content was studied in the mature roots of field and greenhouse-grown turnip. A decrease in both starch and sugar levels was recorded in roots after storage at 0°C for 4 weeks. On the other hand, when plants were exposed to a series of cold treatments, the starch level remained constant but the level of sugars increased in roots. In our studies, turnip roots exhibited the capacity to synthesize and degrade specific glucosinolates at low temperatures. The implications of these findings on the sensory characteristics of the root will be discussed.

Physical Properties of Natural and Synthetic Rubber Materials at Low Temperatures

1953 ◽  
Vol 26 (1) ◽  
pp. 166-180
Author(s):  
J. Z. Lichtman ◽  
C. K. Chatten
Keyword(s):  
Physical Properties ◽  
Low Temperatures ◽  
Test Method ◽  
The Other ◽  
Atmospheric Aging ◽  
Synthetic Rubber ◽  
Other Hand ◽  
Liquid Immersion ◽  
Stiffness Characteristics ◽  
Made In

Abstract A torsional apparatus and a hardness indentation tester have been found to be essentially equivalent for use in evaluating the stiffness characteristics of elastomers over a range of low temperatures. The torsion apparatus, requiring the use of relatively small specimens, facilitates carrying out various conditioning cycles on a material, such as liquid immersion or atmospheric aging. The indentometer, on the other hand, permits the employment of larger sized specimens or even samples, such as relatively thick gasket stocks. There are, then, individual advantages in each apparatus which would determine the choice to be made in selecting a test method for a particular specification.

Ultravibratomy Applied in Ultrathin Sectioning Results in Sections Without Distortions and Compression.

1999 ◽  
Vol 5 (S2) ◽  
pp. 418-419
Author(s):  
Daniel Studer ◽  
Helmut Gnagi
Keyword(s):  
Low Temperatures ◽  
Cutting Edge ◽  
The Other ◽  
The Past ◽  
Other Hand

When resins are ultrathin sectioned they are compressed in the sectioning direction. The amount of compression depends very much on the sectioning angle on one hand, and on the properties of the resin on the other hand. Shortening of the sections in the sectioning direction is in the range of 5 to 35%. Even more compression occurs during cryosectioning of vitreous samples at very low temperatures (-170°C); the range was measured to be 30 to 60% (1).To reduce these compression phenomena, there is basically only one approach possible. The sectioning angle has to be reduced as much as possible. In the past it was shown that by reducing the knife angle from 45° to 35°, a reduction of compression by appoximately one third was achieved (2). The problem with diamond knives is, that the smaller the knife angle, the more susceptible the cutting edge becomes. In practice angles smaller than 35° are not used because of this limitation.

scholarly journals Środki obrony pozwanego przed nakazem zapłaty jako tytułem zabezpieczenia

2021 ◽  
Vol 32 (1) ◽  
pp. 40-49
Author(s):  
Katarzyna Kajmowicz ◽  
Keyword(s):  
The Other ◽  
Effective Protection ◽  
Other Hand ◽  
The Subject

The payment order in the writ proceedings is also a security title. In this case, the court does not issue a separate procedural decision, which excludes the possibility of appealing the security by the defendant. It is a regulation favorable to the claimant and results in effective protection of the claimed claim. On the other hand, the question arises as to the defendant's defenses against an order for payment as security, which is the subject of the consideration.

scholarly journals Winter frost resistance of Hayward and Matua kiwifruit cultivars

2011 ◽  
Vol 31 (No. 1) ◽  
pp. 27-30 ◽  
Author(s):  
M. Burak ◽  
H. Samanci ◽  
M. Büyükyilmaz
Keyword(s):  
Low Temperatures ◽  
Frost Resistance ◽  
The Other ◽  
Other Hand ◽  
Artificial Freezing ◽  
Horticultural Research ◽  
Research Institute

This study was carried out in Atat&uuml;rk Central Horticultural Research Institute at Yalova in 1996 and 1997 in order to determine the frost resistance ability of fruit buds of Hayward and Matua cultivars by artificial freezing tests during winter months. Twig samples for artificial freezing tests were taken one week after defoliation, and at three-week intervals throughout the winter. The buds were exposed to temperatures of &ndash;10&deg;C, &ndash;13&deg;C and &ndash;15&deg;C for 2, 4 and 6 hours. Then they were planted in a greenhouse for survival tests. It was found that &ndash;13&deg;C and &ndash;15&deg;C were very harmful temperatures for both cultivars even for the duration of 2 hours at &ndash;15<sup>0</sup>C. On the other hand, both cultivars could resist to &ndash;10&deg;C for the duration of 6 hours. In general, Hayward is more sensitive to frost than Matua. Both cultivars showed higher resistance in February. As a result, Hayward and Matua cultivars could be grown safely in areas with as low temperatures as &ndash;10&deg;C in winter months. &nbsp;

POSSIBLE DUAL COLD-HARDINESS STRATEGIES IN CISSEPS FULVICOLLIS (LEPIDOPTERA: ARCTIIDAE)

1986 ◽  
Vol 118 (12) ◽  
pp. 1309-1311 ◽  
Author(s):  
Paul G. Fields ◽  
Jeremy N. McNeil
Keyword(s):  
Cold Hardiness ◽  
Prolonged Exposure ◽  
Extracellular Fluid ◽  
Ice Crystals ◽  
The Other ◽  
Ice Formation ◽  
Lethal Temperature ◽  
Other Hand ◽  
Freeze Tolerant ◽  
Lower Lethal Temperature

Insects are usually classified as either freeze-intolerant or freeze-tolerant (Danks 1978; Sømme 1982; Baust and Rojas 1985). Freeze-intolerant species cannot survive the formation of ice in their bodies and typically lower their supercooling points (SCP), the temperature of spontaneous ice formation, during the winter months (Sømme 1982). This is the lower lethal temperature for the insect, although prolonged exposure to temperatures above this may be harmful (Turnock et al. 1983). On the other hand, freeze-tolerant insects can survive the presence of ice crystals in their extracellular fluid and usually have nucleators that prevent supercooling below – 10°C (Zachariassen 1982).

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

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