The thermal behaviors of Pyro-and Tripoly-phosphate solutions and its freeze-dried solid were investigated using DSC. In this study, ATP related compounds, which are similar on structure to tripolyphosphate, were also investigated. It was found that every phosphate solution system is freeze-concentrated, and finally not precipitate but turns to glassy state. And also, its freeze-dried samples were in glassy state. From moisture dependence of their glass transition temperature, the state diagrams, including glass transition line, were constructed. The glass transition temperatures Tg' (-15℃〜-39℃) of their maximum freeze concentrated solution were found to be relatively higher in comparison with those of sugar solutions.

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To deal with cold temperatures different organisms adopt a variety of strategies. Some Animals migrate to warmer climes when winter comes, while other hibernate. However, plants, microorganisms and polar organisms that cannot find a warm haven must find other strategies to deal with cold temperatures. The psychrotrophic ice-nucleating bacterium, Pseudomonas fluorescens KUIN-1 respond to a decrease in temperature with the induction of proteins that are classified as cold acclimation proteins(CAPs). We found the function of a 26 kDa protein of the CAPs in the strain KUIN-1. Strain KUIN-1, a cold shock from 18 to 4℃ induced the synthesis of the 26 kDa protein. The purified 26 kDa protein is composed of 6 subunits of 26, 500 with a molecular mass of approximately 159 kDa according to gel filtration and SDS-PAGE. The N-terminal sequence of the 26 kDa protein was QAAYYPAHHHQQGQQHWGHH-. Specifically, 26 kDa protein of the CAPs of strain KUIN-1 was very effective in protecting the cold-labile enzyme, lactate dehydrogenase against denaturation by freezing. The characterization of 26 kDa protein is analogous to the cold-regulated protein of the plants. An antifreeze protein secreted to the growth medium by the psychrotrophic bacterium, Moraxella sp. was purified to apparent homogeneity. The purified protein has a molecular mass of 52 kDa, containing a lipid moiety. The N-terminal sequence of the 52 kDa protein was GVTISPLLLGYHYTGEAHDG-. This finding suggests that an antifreeze protein is likely to be most important for an adaptation to low temperatures.

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DSC rewarming traces of cross-linked dextran gels of a certain density of cross-link were known to indicate an endothermic trend at low temperatures below 0℃, followed by an exotherm due to ice crystallization prior to a large endotherm due to ice melting at around 0℃. To elucidate the origin of the endothermic trend observed with cross-linked dextran gels, oscillation DSC as well as X-ray diffraction-DSC simultaneous measurements were carried out. By the oscillation DSC measurement, the endothermic trend during rewarming did not change independent of the frequency and amplitude of the temperature oscillation used in this study. The result obtained indicates that the trend is not of a kinetic origin due to enthalpy relaxation nor is the change in heat capacity on the glass transition. However, decrease in the degree of crystallinity of ice was hardly observed by the X-ray diffraction measurement during the endothermic trend in the DSC scan although the exotherm following the endothermic trend was confirmed to be due to ice crystallization by the X-ray diffraction measurement.

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The low-temperature thermal behavior of alkali metal chloride-sugar aqueous solutions was investigated by differential scanning calorimetry (DSC). Glucose, galactose, mannose and fructose were used as sugar. From the results, in case of NaCl-sugar aqueous solutions, glass transition points (Tg) during warming after cooling were almost the same for the four sugars but crystallization points (Tc) due to devitrification were different. In case of KCl-sugar aqueous solutions, Tg s and Tc s were almost the same.

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When the refrigerated tubes for vapor trap are designed, the condensing area of the trap, the arrangement of refrigerated tubes, the pitch of the tubes and the refrigerator unites will give a great effect on the condensing efficiency during the freeze drying. It is necessary to analysis flow of water vapor through the trap and heat transfer from ice layer to refrigerant in the tubes. This paper has developed a mathematical model for calculating the condensing efficiency of the vapor trap and optimum design, based on the increase of vapor flow resistance and heat transfer resistance as increase of ice layer. Experimental studies have been made for the vapor trap efficiency.

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Miscibility of polymers in aqueous frozen solutions was studied through thermal analysis. Freeze-concentration separated some polymer combinations (e.g., PVP and dextran) in single-phase initial solutions into different amorphous phases among ice crystals. Other polymer combinations (e.g., PVP and ovalbumin) were concentrated into mixed amorphous phase. Addition of salts altered the polymer miscibility by covering the electrostatic interaction and hydration state of polymers. Possible mechanisms and effects of the phase separation were discussed.

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Three-dimensional behavior of ice crystals and cells during the freezing and thawing of biological tissues was investigated microscopically in time-series by using a confocal laser scanning microscope (CLSM) and a fluorescent dye, acridine orange (AO). Fresh tender meat (2nd pectoral muscles) of chicken was stained with the AO in physiological saline with or without 2.00M dimethylsulfoxide, and then frozen and thawed in a uniform temperature under four different thermal protocols. The CLSM noninvasively produced tomograms of the tissues in time-series to clarify the pattern of freezing, morphology of extra- and intracellular ice crystals in the tissues, and the interaction between ice crystals and cells.

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Rheological and electrical properties of agricultural products were measured to analyze the mechanism of freeze-injury. Dynamic elesticity and dynamic viscosity, measured by vibrating-reed method, were largely decreased through freezing-thawing. Freezing-thawing also caused substantial decrese in electrical impedance at the frequency range around 100 kHz, showing the freezing damage on plasma membrane of agricultural products. This seemed to cause the loss in turger presure of cells, which explained the large change in Theological properties after freezing-thawing. Rheological properties of eight kind of agricultural products, such as Japanese raddish, potato, carrot, apple, pumpkin, etc., were measured and compared with one another before and after freezing.

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We have reported that the 1.8% paraformaldehyde-fixed and lyophilized human platelets retained surface Glycoprotein Ib with functional, and that may be one of the candidates as platelets substitute. In this paper, we focused on fibrinogen receptor, glycoprotein IIb/IIIa (GP Ilb/IIIa) on plasma membrane which is essential for hemostasis. To maintain GP IIb/IIIa with fibrinogen-binding activity, we activated fresh human platelets with ADP and subsequently fixed with 2 % paraformaldehyde. Aggregation analysis and flowcytometric analysis demonstrated that ADP activated, lyophilized and rehydrated platelets possessed not only ristocetin-dependent aggregation but fibrinogen-binding activity on platelet surface. These results indicate that ADP-activated and lyophilized platelets retain not only functional GP Ib but also surface GP IIb/IIIa in an activated form. This study suggest that ADP-activated and lyophilized platelets may effectively stop bleeding in patients with thrombocytepenia, and may be useful as a platelet substitute.

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Role of trehalose on water status of cut bulbous flowers was determined by T_1 T_2 (^1H-NMR relaxation times) and with isopiestic psychrometers in relation to sugar accumulation and protein content at growth and senescence stages. Treatment with 100mM or 50mM trehalose markedly prolonged vase-life in gladiolus and tulip flowers, respectively. Trehalose maintained a higher degree of water content accompanying with supressing protein degradation in gladiolus petals than control tissues. Short T_2s estimated as bound water from cytoplasm and the apoplastic regions were determined by solid echo technique. Preserving the initial values in short T_2s at 3d after trehalose-treatment suggested that bound water in gladiolus petal tissues was maintained. On the other hand, long T_1 of the intracellular water in tulip tepal tissues showed that trehalose functioned to protect vacuolar water. Furthermore, trehalose affected to enhance water uptake into tepal tissues though not to promote cell elongation and not to cause osmotic adjustment with maintaining high level of turgor. From these results, it suggests that trehalose does not act as an energy source or directly participate in osmoregulation and these characteristics distinguish it from other sugars such as sucrose. In cut gladiolus and tulip flowers trehalose may play an important role to prevent loss of water determined by T_1, T_2 and turgor with protecting macromolecules.

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We examined the effect of post-thaw culture medium on the viability of cryopreserved plant cells to obtain the higher survival rate of the preserved cells. Addition of activated charcoal to the culture medium increased the survival rate of cryopreserved Lavandula vera cells. Elimination of ammonium ion from the culture medium also enhanced the survival rate of cryopreserved Lavandula and rice cells. Amino acids differed in their effect on the survival rate of cryopreserved Lavandula cells. These results indicate that post-thaw culture condition is an important factor to determine the survival rate of cryopreserved plant cells.

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Supercooling and vitrification of aqueous solutions of ethylene glycol, glycerol, DMSO and sucrose were investigated by emulsion method under pressure. It is shown that vitrification of emulsified aqueous sucrose solution is achieved at the solute concentration of R=50 (R=moles of water/moles of solute) under pressure of about 200 MPa. In addition, viability of cultured carrot cells in concentrated sucrose solution (55 wt%) was studied under high pressures. Even at room temperature, viability of carrot cells rapidly decreases above 100 MPa.

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Effect of sucrose on the development of freezing tolerance was investigated in suspension-cultured cells of carrot (Daucus carota L.). Noticeable increase in freezing tolerance was observed in the cells precultured on media containing high concentrations of sucrose. The incorporation of sucrose from the medium was suggested from the analyses of sugar and osmotic pressure of cell-free extracts of the precultured cells. Little or no effect of ABA on the development of freezing tolerance was observed when this hormone was added to the media with or without high concentrations of sucrose.

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Suspension-cultured cells of Arabidopsis thaliana were encapsulated in alginate gel and cultured in media with high concentrations of sucrose. These cultured cells were cryopreserved in LN_2 after dehydration on silica gel. The encapsulated cells of A. thaliana showed the higher survival rate after dehydration than those of cultured-cells of Oryza sativa and Daucus carota. These results suggest that A. thaliana cells have the high tolerance to dehydration. The cryopreserved cells of A. thaliana sometimes failed to grow and this harmed growth was improved when these cells were precultured on medium with a high concentration of CaCl_2 before culture for regrowing.

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