Warming rate

Henry, M.A., Nodes, E.E., Gao, D., Mazur, P., Critser. J.K. (1993). Cryopreservation of human spermatozoa. IV. The effects of cooling rate and warming rate on the maintenance of motility, plasma membrane integrity, and mitochondrial function. Fertil. and Steril. 60,911-918. 

Leibo, S.P., Farrant, J., Mazur, P., Hanna, M.G., Jr., Smith, L.H. (1970). Effects of freezing on marrow stem cell suspensions Interactions of cooling and warming rates in the presence of PVP, sucrose, or glycerol. Cryobiol. 6, 315-332. 

Mazur, P. Rigopoulos, N, (1983). Contributions of unfrozen fraction and of salt concentration to the survival of frozen human erythrocytes Influence of warming rate. Cryobiol. 20, 274-289. 

The crystallization energy, extrapolated for the warming rate zero is calculated for mannitol (13.5 kJ/Mol) and forNa-cefazolin (39,1 kJ/Mol). These data agree with measurements by other methods. The activation energies are generated with certain assumptions to be 335 kJ/Mol for mannitol and 260 kJ/Mol for Na-cefazolin. DeLuca L1.31J derived at with slightly different data at a warming speed of 0.625 °C/min, he found 16.3 kJ/Mol for mannitol and 41.8 kJ/Mol for Na-cefazolin. 

Fig. 1.47. Crystallization energy of sodium cefazolin as a function of the warming rate, measured by DSC (Fig. 2 from [1.301).

HeatTrodes can function as in situ heat exchangers to achieve effective warming rates for bioremediation and soil vapor extraction processes. 

IV. Smaller but possibly significant effects of warming rate and packaging environment are shown in Figure 6, complicated by interaction with the irradiation temperature. The effects of both packaging and warming rate variables were largest at — 196°C. The lowest irradiation flavor intensity... 

Effect of Postirradiation Warming Rate. The effect of postirradiation warming rate was studied at — 196°C. and 6.0 megarads for oxygen- and vacuum-packed steaks under conditions designed to maximize any possible effects. The postirradiation warming was carried out under the following conditions ... 

Slow Warming Rate. Eight cans of steaks packed in an oxygen atmosphere and eight cans of vacuum-packed steaks were held at — 196°C. after irradiation for 96 hours and then allowed to warm slowly in an insulated box, warming from —196° to 4°C. in 31 hours. 

Table VI. Effect of Postirradiation Warming Rate on Irradiation Flavor Scores of Steaks Irradiated at — 196°C. at 6.0 Megarads...

Differences owing to warming rate are also to be expected on the basis of electron spin resonance studies (37) of protein and peptide systems which indicate that the free radicals observed on — 196°C. irradiation differ from those observed on room temperature irradiation and that the types observed at — 196°C. are transformed to the form observed at room temperature on wanning. Since some of the low temperature free radicals have half-lives of the order of days at — 196°C., long holding times and/or slow... 

Effect of Packaging Environment. Because of the opposing effects of postirradiation warming rate on steaks packed in an oxygen atmosphere and on vacuum-packed steaks discussed above, it was not possible to establish a clear preference on the basis of initial irradiation flavor intensity scores. 

Organoleptic studies on irradiated beefsteaks showed that irradiation flavor intensity is significantly lower at lower irradiation temperatures and depends on postirradiation warming rates. 

Figure 8 Effect of warming rate on the DSC thermograms of glycine/water in the melting region of ice.

Fig. 1.22.1a. Electrical resistance as a function of temperature of 1% NaCl solution. Cooling rate 3 °C/min, warming rate 3 °C/min and the first derivative d(logR)/d7"measured down to-120°C...

Experimental parameters such as evaporation method, solvent polarity and viscosity, and warming rate during cluster formation were varied. Cluster/crystallite size and particle surface area were monitored. Additional information was gleaned from Mossbauer, Differential Scanning Calorimetry (DSC), and X-Ray Photoelectron Spectroscopy (XPS). 

The slower warming rate and minimization of large viscosity gradients tend to allow reaction 4 to compete better with reaction 3. Thus, solvent fragmentation/ligation (reaction 4) competes better over the slow warm-up period. 

Figure 2. Warming-rate dependence of catalase inactivation in various solutions after seeding and quenching in liquid nitrogen. Mean and SE are shown for 4-6 samples in each case. Rates were controlled from —20, —30, and —50°C or lower for solutions containing phosphate only, KCl, and NaCl, respectively...

Since warming rates in excess of 20°/min prevented enzyme damage, we utilized this feature to evaluate the temperature range over which damage occurred. In Figure 3A samples were quickly frozen at —78° then transferred to a — 20° alcohol bath which was then warmed slowly to various subzero temperatures, after which the tubes were quickly... 

---