Effect of drying methods on the solubility and amphiphilicity of room temperature soluble gelatin extracted by microwave-rapid freezing-thawing coupling

2021 ◽  
Vol 351 ◽  
pp. 129226
Author(s):  
Xin Feng ◽  
Hongjie Dai ◽  
Liang Ma ◽  
Yu Fu ◽  
Yong Yu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Drying Methods ◽  
Rapid Freezing

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

Rapid freezing of the mouse blastocyst: effects of cryoprotectants and of time and temperature of exposure to cryoprotectant before direct plunging into liquid nitrogen

1991 ◽  
Vol 3 (2) ◽  
pp. 175 ◽  
Author(s):  
R Li ◽  
A Trounson
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Rapid Freezing ◽  
High Concentration ◽  
Freezing And Thawing ◽  
Initial Exposure ◽  
Survival And Development ◽  
High Concentrations

This study investigates the effects of time and temperature of exposure to a high concentration (4.5 M) of dimethyl sulfoxide (DMSO), glycerol, 1,2-propanediol (PROH), or a mixture of DMSO and glycerol (DG) in a solution containing 0.25 M sucrose, on the survival and development of rapidly frozen mouse blastocysts. Embryos had significantly (P less than 0.01) higher rates of survival and development when exposed to cryoprotectant at 0 degree C compared with room temperature. The time of exposure to cryoprotectant at either 0 degree C or room temperature before being plunged into liquid nitrogen significantly (P less than 0.01) affected the survival and development of frozen-thawed embryos. Survival and development of blastocysts in vitro and in vivo was significantly (P less than 0.05) higher when exposed at 0 degree C for 10 min to DG, DMSO and glycerol than to PROH. It is concluded that, unlike early-cleavage stage embryos, blastocysts need to be equilibrated at a low temperature (0 degree C) with high concentrations of cryoprotectant before rapid freezing. Exposure of blastocysts to 4.5 M cryoprotectant and 0.25 M sucrose at room temperature either was toxic or else markedly reduced their viability after freezing and thawing, depending on the duration of the initial exposure.

scholarly journals Dynamics of acousto-convective drying of sunflower cake compared with drying by a traditional thermo-convective method

2018 ◽  
Vol 6 (2) ◽  
pp. 370-378 ◽  
Author(s):  
Aleksandr Zhilin ◽  
Aleksandr Zhilin ◽  
Aleksandr Fedorov ◽  
Aleksandr Fedorov ◽  
Dmitry Grebenshchikov ◽  
...  
Keyword(s):  
Room Temperature ◽  
Absolute Humidity ◽  
Convective Drying ◽  
Drying Methods ◽  
Flow Temperature ◽  
Moisture Extraction ◽  
Minute Interval ◽  
Optimal Mode ◽  
Sunflower Cake ◽  
Convective Mode

The article is devoted to the dynamics of sunflower cake drying in a fundamentally new acousto-convective way. Unlike the traditional (thermo-convective) method, the method proposed allows extracting moisture from porous materials without supplying heat to the sample. Thermo-vacuum drying helped to determine the absolute and relative initial moisture for the analysed samples of the sunflower cake, which equaled 313.1% and 75.8%, respectively. The kinetic curves for drying by thermo- and acousto-convective methods were obtained and analysed. A study of the acousto-convective drying of sunflower cake showed that the rate of moisture extraction depended on the resonating frequency, while there is an optimal mode in which drying proceeds from two to three times more intensively. In thermo-convective drying of sunflower cake, increasing the temperature of the drying stream twice (from 74.2°C to 127°C) reduces the duration of drying to a final absolute humidity of 40% three times. Comparing the thermo-convective and acousto-convective drying methods showed that twice as much moisture was removed from the samples dried by the (ACDP) with a flow frequency of 790 Hz and at room temperature for a 30-minute interval as with thermal convective drying with a working flow temperature of 127°C. The relaxation mathematical model used to describe the drying phenomenon and the experimental data for sunflower cake drying allows obtaining the quantitative parameters characterizing different modes and methods of drying the samples under study. The article analyses a discrete drying regime that contributes to increasing the efficiency of the acousto-convective mode of moisture extraction.

scholarly journals Methods and Principles of Fixation by Freeze-Substitution

1958 ◽  
Vol 4 (5) ◽  
pp. 593-602 ◽  
Author(s):  
Ned Feder ◽  
Richard L. Sidman
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Picric Acid ◽  
Freeze Substitution ◽  
Tissue Structure ◽  
Chemical Agent ◽  
Rapid Freezing ◽  
Chemical Mechanisms ◽  
Accurate Localization

Freeze-substitution is based on rapid freezing of tissues followed by solution ("substitution") of ice at temperatures well below O°C. A 1 to 3 mm. specimen was thrown into 3:1 propane-isopentane cooled by liquid nitrogen to -175°C. (with precautions). The frozen tissue was placed in substituting fluid at -70°C. for 1 week to dissolve ice slowly without distorting tissue structure. Excess substituting agent was washed out, and the specimen was embedded, sectioned, and stained conventionally. For best morphological and histochemical preservation, substituting fluids should in general contain both chemical fixing agent and solvent for ice, e.g., 1 per cent solutions of osmium tetroxide in acetone, mercuric chloride in ethanol, and picric acid in ethanol. Preservation of structure was poorer after substitution in solvent alone. Evidence was obtained that the chemical agent fixes tissue at low temperatures. The chemical mechanisms of fixation are probably similar to those operating at room temperature: new chemical cross-linkages, which contain the fixing agent, join tissue constituents together. This process is distinguished from denaturation by pure solvents. Freeze-substitution has many advantages, particularly the preservation of structure to the limit of resolution with the light microscope, and the accurate localization of many soluble and labile substances.

scholarly journals Safety Considerations Regarding the Use of Propane and Other Liquefied Gases as Coolants for Rapid Freezing Purposes

1998 ◽  
Vol 6 (2) ◽  
pp. 16-17
Author(s):  
Keith P. Ryan ◽  
Malcolm I. Liddicoat
Keyword(s):  
Vapour Pressure ◽  
Room Temperature ◽  
Freezing Point ◽  
Fold Increase ◽  
Nitrogen Atmosphere ◽  
Coolant Temperature ◽  
Rapid Freezing ◽  
Liquid Propane ◽  
Safety Considerations ◽  
Small Room

Liquid propane and similar coolants are used in the rapid freezing of biological specimens. These coolants form explosive gas mixtures with air with a 14,000-fold increase in volume over that of the liquid. The liquefied gases have high vapour pressures and, unless they are maintained below their flashpoint, the vapour above them will reach ignitable concentrations. The flashpoint of liquid propane is -104°C. Ethane has a higher vapour pressure, and vapour mixed with air above liquid ethane can be ignited at a coolant temperature of -130°C. The danger is minimized if the coolant is maintained near its freezing point and under a nitrogen atmosphere, in a fume cupboard. Liquid nitrogen evaporates to a 690-fold increase in volume at room temperature. It is important to ventilate the working area, especially when cryo-sectioning in a small room, otherwise there is a possibility of asphyxiation.

scholarly journals Change of antioxidant compounds of spices during drying

2019 ◽  
pp. 77-81
Author(s):  
Andrea Kántor ◽  
Loránd Alexa ◽  
Emőke Papp-Topa ◽  
Béla Kovács ◽  
Nikolett Czipa
Keyword(s):  
Water Content ◽  
Dry Matter ◽  
Room Temperature ◽  
Matter Content ◽  
Antioxidant Compounds ◽  
Drying Methods ◽  
Dry Matter Content ◽  
Original Material ◽  
Air Drying ◽  
Very High

Spices and herbs have been used by humanity for thousands of years, so they are very important plants. In this study, the change of dry matter content and antioxidant compounds of eight spices (basil, thyme, rosemary, mint, parsley, lemongrass, chives, coriander) have been examined the raw plants and in plants preserved by three different drying methods (an oven in 50–60°C; drying at room temperature; lyophilisation between -40 and -50°C, under pressure), because we wanted to see the change of the parameters. The water content of raw plants was very high, i.e. the dry matter content was very low. By the application of the three drying methods nearly 100% of the water has left the plants, with the exception of the lyophilized basil and rosemary. Based on the results related to the original material, lyophilized has proved to be the best treatment for the preservation of antioxidant compounds, however air drying also showed high results for some spices.  

scholarly journals Researching the change in the weight of split oak firewood due to different drying methods

2021 ◽  
Vol 1208 (1) ◽  
pp. 012023
Author(s):  
Amina Gačo
Keyword(s):  
Room Temperature ◽  
Average Weight ◽  
Drying Methods ◽  
Initial Water Content ◽  
Initial Weight ◽  
Average Amount ◽  
Initial Amount ◽  
Initial Water ◽  
Original Weight ◽  
Air Circulation

Abstract In this paper, the influences of stacking methods and drying places of split oak firewood in winter conditions (Quercus cerris) have been experimentally and theoretically investigated, due to the great importance of use in heating with such wood. The research was conducted on a sample of 48 pieces of logs with bark made of freshly cut oak. The logs were obtained by mechanized technology with the help of grafting by a hydraulic splitter and a chainsaw. Each log was measured for a research length of 0.30 m, marked with numbers 1-24. On each log, the weight was measured on a scale of 5 kg with an accuracy of 0.5 grams. Drying of logs was performed in two places. The first drying place was in outdoor conditions, sheltered from the snow and ventilated. The second place was indoors, at approximately constant room temperature. The logs were stacked in a crossed way for better air circulation. They were dried between 15/12/2020 and 15/02/2021, a total of 62 days. The average initial weight of logs dried in the facility was 1130.3 g, in the dried state the average weight was 952.87 g, which represented 84.3% of the original weight. The average initial weight of logs dried in outdoor conditions was 1192.125 g, in the dried state 1076.37 g, which represented 90.29% of the original weight. The average initial water content in the logs dried in the facility was 37.9%, in the dried state it was 27.5%. For logs dried in outdoor conditions, the average initial amount of water was 36.6%, in the dried state the average amount of water was 31.2%.

Effect of Drying Methods on Physical Property of the Ultrafine CeO2 Powder

2012 ◽  
Vol 189 ◽  
pp. 92-96
Author(s):  
Yan Hong Hu ◽  
Mei Li ◽  
Zhao Gang Liu ◽  
Mi Tang Wang ◽  
Jin Xiu Wu
Keyword(s):  
Particle Size ◽  
Organic Solvent ◽  
Freeze Drying ◽  
Room Temperature ◽  
Physical Property ◽  
Microwave Drying ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Large Specific Surface Area ◽  
Solvent Displacement

The ultrafine CeO2 powder was prepared using NH4HCO3 as precipitation agent. The effects of six drying methods, such as room-temperature drying、common oven drying、microwave drying、organic solvent displacement drying、freeze drying、vacuum drying, on hard agglomerates and physical property of CeO2 were studied. The results showed that freeze drying is more effective to prevent the ultrafine CeO2 powder from hard agglomerates. The ultrafine CeO2 powder with small mean particle size and uniform distribution and large specific surface area，was obtained by freeze method.

FACTORS AFFECTING THE VIABILITY OF FROZEN OVARIAN TISSUE

1958 ◽  
Vol 17 (4) ◽  
pp. 337-343 ◽  
Author(s):  
A. S. PARKES
Keyword(s):  
Room Temperature ◽  
Ovarian Tissue ◽  
Horse Serum ◽  
Slow Freezing ◽  
Rapid Freezing ◽  
Freezing Damage ◽  
Two Stage ◽  
Factors Affecting ◽  
One Stage

SUMMARY Viability of rat ovarian tissue frozen and thawed in vitro was assessed by its capacity to form an endocrinologically active autograft, and variables associated with the treatment have been studied. Other neutral solutes tested were not as effective as glycerol in protecting against freezing damage, and 15% (v/v) glycerol was more effective than 10% and much more effective than 5%. The duration of soaking before slow freezing can be reduced with advantage from 1 hr to 15 min. One-stage rapid freezing to −79° C was very damaging to the tissue as compared with slow freezing, but two-stage rapid freezing, recently described as being effective with bull spermatozoa, gave intermediate results. Tissue frozen in glycerol-saline deteriorates rapidly after thawing if left at room temperature, but transference to glycerol horse serum after thawing largely preserves viability. Some implications of this result are discussed.

Survival of rapidly frozen hatched mouse blastocysts

Zygote ◽  
2003 ◽  
Vol 11 (4) ◽  
pp. 361-366 ◽  
Author(s):  
Csaba Pribenszky ◽  
Sándor Cseh ◽  
Zsolt Abonyi-Tóth ◽  
László Solti
Keyword(s):  
Liquid Nitrogen ◽  
Zona Pellucida ◽  
Room Temperature ◽  
Calf Serum ◽  
Significant Loss ◽  
Rapid Freezing ◽  
Foetal Calf Serum ◽  
Freezing Medium

The objective of the present study was to examine the effect of rapid freezing on the in vitro and in vivo survival of zona-pellucida-free hatched mouse blastocysts. Hatched blastocysts were rapidly frozen in a freezing medium containing either ethylene glycol (EG) or glycerol (G) in 1.5 M or 3 M concentration. Prior to freezing, embryos were equilibrated in the freezing medium for 2 min, 10 min, 20 min or 30 min at room temperature. To freeze them, embryos were held in liquid nitrogen vapour [≈1 cm above the surface of the liquid nitrogen (LN2)] for 2 minutes and then immersed into LN2. After thawing, embryos were transferred either to rehydration medium (DPBS + 10% foetal calf serum + 0.5 M sucrose) for 10 minutes or rehydrated directly in DPBS supplemented with foetal calf serum. In vitro survival of embryos frozen with EG was higher than those frozen with G. The highest survival was obtained with 3 M EG and 2 min or 10 min equilibration prior to freezing, combined with direct rehydration after thawing. Frozen blastocysts developed into normal foetuses as well as unfrozen control ones did, with averages of 30% (control), 26% (EG) and 15% (G). The results show that hatching and hatched mouse blastocysts can be cryopreserved by a simple rapid freezing protocol in EG without significant loss of viability. Our data indicate that the mechanical protection of the zona pellucida is not needed during freezing in these stages.

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