Contact Freezing Research Articles

Freeze-fracture Observations on the Rat Sertoli Cell Junctions by Metal Contact Freezing

Freeze-fracture Observations on the Rat Sertoli Cell Junctions by Metal Contact Freezing

Desalination of Saline Water by Direct Contact Freezing Process Using Liquid Nitrogen

Desalination of Saline Water by Direct Contact Freezing Process Using Liquid Nitrogen

Studies on Fibrinolysis and Coagulation in the Peptic Ulcer (1st Report)

(Object) There are many reports on the fibrinolytic dynamics in blood as to the development of peptic ulcers. However, these studies have not been completed and we have many problems to be solved on this subject. In the present study we reexamined the correlation between the fibrinolysis and activity of the coagulation system.(Method) Ulcers were induced by contact freezing of the left gastric artery on the gastric serosa in Mongorel dogs for materials. The basis of ulcers was confined within the limit of the submucosal layer in all cases and fibrin deposit blood vessels were maintained comparatively intact. The plasminogen activator was observed at necrotic portions, but activity was determined at the margin, peripheral elevation and distal mucosa of ulcers and the plasminogen and plasmin inhibitors in the circulating blood were analyzed by affinity chromatography at the same time. The tissue was observed by antifibrinous staining.(Result) At the margin of ulcer: Free plasminogen activator was proved at the local peripheral circulatory insufficiency but it was diministred after this maniplation. In the peripheral elevation of ulcer: Free activator was detected when circulatory insufficiency was invited and a secondary liberation of the activator due to the elevation of membrane permeability of peripheral cells containing quinines was observed. In the distal mucosa: The same correlation as in the peripheral elevation was noticed, but the secondary liberation of activator showed considerably wide variation. The activity of plasminogen or plasmin inhibitors was correlated with that of plasminogen activator in blood. The coagulation system had an inhibitory action on factors V and VIII, but it was correlated with neither PT nor PTT.(Conclusion) The activity of plasminogen activator in the initial lesions of acute peptic ulcers showed clear biphasic peaks and was well correlated with that of plasmin inhibitor or of the coagulation system at the same time.

FREEZING OF VEGETABLES BY DIRECT CONTACT WITH AQUEOUS SOLUTIONS OF ETHANOL AND SODIUM CHLORIDE

ABSTRACTAqueous freezant (AF 15–15) consisting of 15% NaCl and 15% ethanol with a −19.3°F solubility limit was developed for direct contact freezing of vegetables. Carrots (3/8 in. dice) and peas were frozen and cooled to 2.5°F in 1.5 min of immersion and beans (1 in. cut) and whole kernel corn were frozen and cooled to 2.5°F in 2.5 min of immersion. AF 15–15 frozen and blotted peas, beans and corn contained 0.72–0.82% NaCl and were statistically indistinguishable from air‐blast frozen vegetables in organoleptic ratings. Air‐blast frozen carrot dice were preferred over AF frozen dice which contained 1.77% NaCl. A mixture of all of the above vegetables frozen in AF 15–15 was slightly favored over an air‐blast frozen mixture (6.7 vs 5.8 score). AF frozen vegetables showed a small (2.3–0.9%) weight gain, whereas the air‐blast frozen vegetables showed losses of from 3.9–13.3% with respect to fresh weight.

Migration of neuroblasts through partial necrosis of the cerebral cortex in newborn rats-contribution to the problems of morphological development and developmental period of cerebral microgyria. Histological and autoradiographical study.

Focal aseptic necrosis of the cerebral cortex was induced in newborn rats by focal contact freezing. In the region of freezing the following changes took place: necrosis of the pia mater, total necrosis of the differentiating Ist–IVth layers of the cortex and partial necrosis of the Vth and VIth layers of the cortex. The VIth-b layer was mostly preserved. In partial necrosis the differentiating neuroblasts died. The capillaries and migrating neuroblasts destined for the Ist, IInd, and IIIrd cortex layer survived. They stopped only at the periphery of total necrosis and continued to differentiate. After healing, an atypical cortex, consisting of four layers, was formed in the necrotic region, quite similar to the microgyric cortex of four layers known in the human. After deeper necrosis a cortical microsulcus developed, also formed by a cortex of four layers. The newly formed first microgyric (molecular) layer had its histologic structure homologous to the molecular layer of the surrounding cortex. The second microgyric layer (outer, cellular one) was formed by neuroblasts assigned to the IInd and IIIrd normal layers, which migrated through partial necrosis and took up their final position at the periphery of total necrosis. The third microgyric (light) layer was formed by the original Vth layer destroyed by partial necrosis, and it contained single neurons and glial cells. The fourth microgyric layer was formed by the persistent deep part of the VIth layer. The four layered cortex was formed only during the time of neuroblastic migration. The findings are discussed in relation to the normal pathogenesis of cortical microgyria in children. The experimental findings show that the microgyric cortex is formed only during the course of neuroblastic migration.

The Role of Contact Nucleation in Ice Phase Initiation in Clouds

Abstract Ice particle multiplication mechanisms are summarized and considered to be incapable of producing the excess of ice crystals over ice nuclei (factors of 102–104) observed in several types of clouds. Contact freezing, sorption and immersion freezing nucleation are re-examined with regard to their temperature and mode of activation. A model of ice phase nucleation based on contact nucleation is advanced. The collection of contact nuclei by drops is considered to result from Brownian motion and phoretic forces. Based on estimated sizes for natural contact nuclei of 0.3–0.5 μm, contact nueleation is predicted to be suppressed in updrafts and enhanced in downdrafts or mixing zones. This correlation is in excellent agreement with observations of first ice in cumuli. Blanchard's drop freezing data are used to deduce concentrations of natural contact nuclei active at −4C of 100–1000 liter−1. These concentrations are noted to be consistent with Hobbs’ observations of 1–10 ice particles liter−1 at −4C in a...

A Numerical Simulation of Wintertime, Orographic Precipitation: Part I. Description of Model Microphysics and Numerical Techniques

A numerical model which extends treatment of microphysical cloud processes to more than one level through use of the continuous bin technique is described. A general solution to the diffusion growth equation including latent heat release due to accretion is presented. Collection processes of coalescence, accretion and aggregation, activation of CCN, and ice phase nucleation through sorption and contact freezing nucleation are combined with a diffusion treatment which allows for calculation of the supersaturation in a multi-level framework and with sedimentation of particles between levels.

Hydrate formation in i-butane- n-butane or a butene isomer water system at a given temperature

In this study- it was first confirmed experimentally that of the four-carbon hydrocarbons, only i-butane seems to be able to form solid hydrate by itself in coexistence with an aqueous phase. Then similar experiments with i-butanef-based binary mixtures with each of these hydrocarbons were carried out at a fixed temperature of -0.7°C. The results show that the relationships between the composition of the mixture used and the equilibrium total pressure can be found approximately by a proposed theoretical consideration. Thus, the mixtures with less than 73.8% i-butane can not form a hydrate at -0.7°C with 1.6% NaCl aqueous solution, and this limiting ratio increases with increasing temperature. For example, the following values are obtained: 84.1%, at 0.0°C and 69.5%, at -1.0°C. The mixtures containing more than the above ratios could form a solid hydrate, whose quantity was proportional to the excess of the i-butane used. Although to justify the above theory, it will be necessary to conduct further studies with propane instead of i-butane at this and/or at other temperatures, it suggests a suitable composition for the secondary refrigerant applied in the direct contact freezing process for the desalination of sea water, from the point of view of the operating pressure and the prevention of hydrate formation.

Correlation between Growth Rate of Ice Crystals and Operating Condition in Direct Contact Freezing Process for Concentration of Sea Water

In order to find the most suitable operating condition for concentration of sea water by means of the direct contact freezing process, a test plant that could be easily operated in a steady state was designed and built.The correlation between linear growth rate of ice crystals and operating condition of this plant was derived from the analysis of experimental data as follows:WI=3βIDIf (α/TDI)where, WI is crytalisation rate (or production rate), I is ice content in brine, T/α is holding time of ice crystals, DI is linear growth rate of ice crystals, and α, β are correction factors.DI was estimated by analysing the size distribution of ice crystals produced in the freezer during operation in its steady state.α was necessary because of the difference between the holding time of ice crystals and that of brine.β was necessary because the total surface area of the crystals varied with the change of the size distribution, even if the cumulative number of the crystals was constant.