High temperature effects

Lurie S, Handros A, Fallik E and Shapira R. 1996. Reversible inhibition of tomato fruit gene expression at high temperature. Effects on tomato fruit ripening. Plant Physiol 110 1207-1214. 

Arora A, Yaduraju NT (1998) High-temperature effects on germination and viability of weed seeds in soil. J Agron Crop Sci 181 35—43... 

High-temperature Effective Pair Potentials for the System N2-N and 02-0. 

Urea (0.01 M), sodium carbonate (0.01 M), magnesium chloride (0.01 M), or distilled water can be used as microwave fluids to obtain similar results in terms of both sensitivity and intensity of the hybridization signal. Alternatively, 10 mM citrate buffer (pH 6.0) can be used as the microwave fluid. The major role of these fluids is to mediate high temperature effects, which is confirmed by the achievement of a good hybridization signal using distilled water. Note that pretreatment conditions must be optimized for every tissue type and for every cell type in a given section. 

Studies of the MA-lysine reaction by other authors, as discussed previously, were conducted at 37°C or lower. There are a few reports of lysine losses measured as a function of increasing temperature to more than 100°C some of these reports correlate these losses with browning and others with moisture content (21-26). However, most studies of high temperature effects have been on browning rather than nutrient loss. 

The effect of temperature satisfies the Arrhenius relationship where the applicable range is relatively small because of low and high temperature effects. The effect of extreme pH values is related to the nature of enzymatic proteins as polyvalent acids and bases, with acid and basic groups (hydrophilic) concentrated on the outside of the protein. Finally, mechanical forces such as surface tension and shear can affect enzyme activity by disturbing the shape of the enzyme molecules. Since the shape of the active site of the enzyme is constructed to correspond to the shape of the substrate, small alteration in the structure can severely affect enzyme activity. Reactor s stirrer speed, flowrate, and foaming must be controlled to maintain the productivity of the enzyme. Consequently, during experimental investigations of the kinetics enzyme catalyzed reactions, temperature, shear, and pH are carefully controlled the last by use of buffered solutions. 

ThCgSample being studied in vacuum (usually better than 10 Torr), it must be a solid, and, if liquid at room temperature (like for pre-polymers with low molecular weight), it must be cooled by some refrigerant circulation. This limits also the possibility to study high temperature effects on such materials. 

In this diagram, AE is the half-width or fi/2, as defined above. Temperature is plotted as T /2 to show high temperature effects. Maximum energy of absorption occurs at the intersection of the extension of the slopes of both sides of the curve. 

Rixecker G, Wiedmann I, Rosinus A, et al. High-temperature effects in the fracture mechanical behaviour of silicon carbide liquid-phase sintered with AIN-Y2O3 additives. J.Euro. Ceram Soc., 2001,21 1 013-1 019. 

FIGURE 40.19 Vacuum drying seeks to reduce the boiling point of water in order to obtain a high-temperature effect with moderate drying conditions. (Saturated vapor pressure values from Lide 1995.)... 

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