• Journal of the Korean Geotechnical Society
• /
• v.32 no.6
• /
• pp.17-26
• /
• 2016

Characteristic behaviors of geo-structure during freezing and thawing process have to be understood based on fundamental knowledge on phase change in porous soil and interaction between soil and structure. Inversion analysis using published one-dimensional soil freezing tests was conducted to suggest a mechanical model to consider an effect of the ice saturation on Young's modulus. Silty soil was more sensitive to temperature than weathered granite soil and sand, and weathered granite soil was more affected by initial water saturation in stiffness decrease than silty soil. Numerical simulations on chilled gas pipeline showed that shielding effect from surrounding frozen zone around the pipe decreases impact from external load onto the pipe. And a pipe installed in sand backfill showed more heaving due to relatively low stiffness of sand during freezing than that of surrounding in-situ weather granite soil. However, it had more stable stress condition due to effective stress redistribution from external load.

• KSBB Journal
• /
• v.16 no.6
• /
• pp.626-631
• /
• 2001

Lactobacilli have been considered to play important roles in the health of human vagina. They secrete inhibitory substances to prevent vaginal infection by pathogenic organisms. In a previous study, we have isolated several lactobacilli from Korean woman and one of them (KLB46) was selected and indentified as Lactobacillu crispatus which showed high antimicrobial activity. In this study. cold adaptation prior to subsequent stresses exposure was examined whether L. crispatus KLB46 maintain the viability better than the non-adapted calls under stresses. For pharmaceutical formulation, the lyophilization process is required where stresses such as freezing/thawing and dehydration are routinely applied. Formulated L. crispatus KLB46 can be used for ecological treatment of bacterial vaginosis. The response of cold-adapted cells to other environmental stresses such as acid, heat, ethanol, NaCl, and H$_2$O$_2$ was also examined. The results showed that cold-adapted cells maintained higher survival rate compared with the non-adapted cells (freezing-thawing. 3-folds; dehydration: 3-folds; acid, 3-folds; heat, 10-folds). However, we did net observe any positive effect of cold adaptation on other stresses such as ethanol, NaCl and H$_2$O$_2$. When chloramphenicol was added during cold adaptation, adaptation effect was abolished. This confirms that de novo protein synthesis is necessary during the adaptation process. Moreover, we have identified cold shock protein homolog that codes for a major cold shock protein by PCR amplification using degenerate primers.

• Restorative Dentistry and Endodontics
• /
• v.46 no.2
• /
• pp.26.1-26.15
• /
• 2021

Objectives: The aim of the present systematic review was to investigate the cryopreservation process of dental pulp mesenchymal stromal cells and whether cryopreservation is effective in promoting cell viability and recovery. Materials and Methods: This systematic review was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and the research question was determined using the population, exposure, comparison, and outcomes strategy. Electronic searches were conducted in the PubMed, Cochrane Library, Science Direct, LILACS, and SciELO databases and in the gray literature (dissertations and thesis databases and Google Scholar) for relevant articles published up to March 2019. Clinical trial studies performed with dental pulp of human permanent or primary teeth, containing concrete information regarding the cryopreservation stages, and with cryopreservation performed for a period of at least 1 week were included in this study. Results: The search strategy resulted in the retrieval of 185 publications. After the application of the eligibility criteria, 21 articles were selected for a qualitative analysis. Conclusions: The cryopreservation process must be carried out in 6 stages: tooth disinfection, pulp extraction, cell isolation, cell proliferation, cryopreservation, and thawing. In addition, it can be inferred that the use of dimethyl sulfoxide, programmable freezing, and storage in liquid nitrogen are associated with a high rate of cell viability after thawing and a high rate of cell proliferation in both primary and permanent teeth.

• Journal of the Korea Convergence Society
• /
• v.12 no.11
• /
• pp.419-426
• /
• 2021

Until recently, various studies for the production of high-acidity vinegar have been conducted, but there have been few studies on the concentration process of vinegar. In this study, the possibility of introducing freeze-concentration method was investigated for the production of high-quality, high-acidity vinegar. Acidity, pH, specific gravity, and glucose concentration were measured for frozen concentrated vinegar fractions obtained by freezing and thawing three types of Rubus coreanus vinegar with different acidy (7.53, 5.43, and 3.72). Acidity, specific gravity, and glucose concentration were all highest when 15% of the original vinegar was thawed. pH was the lowest when 15% of the original vinegar was melted. As a result of the measurement of cumulative acidity, when 20% of the original vinegar was melted, it was the highest at 9.32, which was 3.89 higher than that of the original vinegar. In this study, it was confirmed that vinegar can be effectively concentrated using the freeze concentration method and at the same time, the thawing ratio can be controlled to effectively obtain vinegar with the desired acidity. However, it is considered that studies such as organic acid and amino acid analysis are needed to determine whether the freeze-concentration method is introduced into the high-acidity concentrated vinegar manufacturing process.

• Journal of the Korean Applied Science and Technology
• /
• v.39 no.1
• /
• pp.52-62
• /
• 2022

The purpose of this study was to find a way to improve the stability and quality of urinalysis by checking the changes in the measurement values of representative clinical chemistry test items according to the repeated freezing and thawing before the urine test and the thawing process. All subjects were 10 healthy males, and the freeze and thaw stability test was performed using their urine samples. In the case of micro-albumin and amylase, there was no statistical significance at 37℃ with time, but at 42℃ and 60℃, there was a statistically significant change in the results with time. There were statistically significant changes in BUN, creatinine, uric acid, and glucose. As a result of long-term stability, after 7 days, glucose mutation increased and amylase decreased at 60℃. In the case of glucose and amylase, there was a statistically significant change in the results over time. To obtain accurate test results, accurate standardization of urinalysis including appropriate collection, storage, and storage methods of urine samples is required and systematic study of conditions for securing stability for each biomaterial is required.

• Journal of the Korean Geosynthetics Society
• /
• v.10 no.2
• /
• pp.73-79
• /
• 2011

Based on the results of Part 1 of our two-parts paper, the possibility on field applicability of CMDS(Coal Mine Drainage Sludge) mixed with bentonite and cement as a liner in landfill sites was investigated. The optimum moisture content that met the landfill liner condition was obtained when the ratio of CMDS: bentonite: cement was 1: 0.5: 0.3 in a lab-scale. The relative compaction was measured in 90.1%, which results for construction field have been generally acceptable. In this study, a large-scale Lysimeter($1.0m{\times}1.5m{\times}2.0m$) was used to simulate the effects of the layer on the freeze/thaw by -20 average temperature. The mixture after freezing/thawing showed compressive strength more than $5kg/cm^2$, which was satisfied with EPA standards. Initial permeability of CMDS was $7.10{\times}10^{-7}cm/s$ and permeability its mixture after freezing/thawing was increased to $9.80{\times}10^{-7}cm/s$. The change of temperature in the layers rises and falls with linear and temperature gradient keep maintain the present state. Moisture contents in the layers have not been radically changed. Through the leaching test determined by KSLT method, it was found that heavy metals excluding Zn and Ni were not leached out or leached out less than the standards during 7 cycles of freezing/thawing process. Since it shows the increased permeability about 1.5 times and slight change in moisture content, but it was satisfied with EPA standar through 7 cycles of freezing/thawing process, this mixture can be applied as a liner in landfill final cover system.

• The Korean Journal of Food And Nutrition
• /
• v.12 no.4
• /
• pp.370-374
• /
• 1999

This study was carried out to some properties and curring effect of drip obtained from frozen-thawed park loin ham belly and imported belly by thawing process at 4$^{\circ}C$. Moisture content and pH value of drips were 88.05~90.85% and 5,72~6.05 and do not show significant differences between each samples. Protein contents were 11.07, 8.85, 8,76 and8,13% in the drips from domestic pork loin, ham, belly and imported belly, respectively. Approximately 99% of the drip were constituted with moisture and protein in any part of domestic pork and imported belly. Glutamic acid proline glycine, alanine and lysine were the predominant amino acid in the drips. Curing process of the drip by nitrite increased the pH value and total amino acid content. The residual nitrite decreased during the period of curing and total plate counts in drip with nitrite did not reach 1$\times$105CFU/g until 7 days.

• Journal of Nutrition and Health
• /
• v.36 no.10
• /
• pp.1071-1082
• /
• 2003

The objective of this study was to evaluate and improve the microbiological quality of HACCP application in school foodservice operations. The microbiological quality of foods and utensils were evaluated two times at each critical control point (CCP) with 3M petrifilm in five Daegu elementary schools. Two processes were evaluated: Heating process and after-heating process. The CCPs of the heating process were receiving, cooking and serving temperatures. The CCPs of the after-heating process were personal hygiene, cross contamination avoidance and serving temperature. After the first experiment, 31 employees of five schools were classroom educated, trained on-site, and pre- and post-tested on HACCP-based sanitation with the goal of improving the microbiological quality of the foodservice. Scores representing knowledge of holding, thawing, washing, food temperature, sanitizing and food-borne illness increased after education. In the heating process, internal food temperatures in the first and second experiments were higher than 74$^{\circ}C$, the holding temperature in the first experiment was less than 6$0^{\circ}C$. In the second experiment, the serving temperature improved to a satisfactory level. The microbiological quality in the second experiment improved by decreasing the time from cooking to serving. In the after-heating process, the ingredients were boiled before being cut in the first experiment. In the second experiment, ingredients were cut before being boiled, improving microbiological quality. Also in the second experiment, cooking just before serving food improved its microbiological quality through time-temperature control. These results strongly suggest it is essential to measure microbiological quality regularly and to educate employees on HACCP continuously, especially time-temperature control and cross contamination avoidance in order to improve foodservice quality.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.10
• /
• pp.1276-1281
• /
• 2010

The present study was conducted to investigate the effects of butylated hydroxytoluene (BHT) supplementation on diluted, cooled and frozen-thawed ram spermatozoa. After primary evaluation of collected ejaculates, only semen samples with motility of more than 70% and sperm concentration higher than $3{\times}10^3$ sperm/ml were used for cryopreservation. The selected semen samples were then pooled and diluted 1:4 with Tris Citrate Fructose Yolk (TCFY) extender supplemented with different concentrations of BHT (0.5, 10, 2.0 and 3.0 mM). As the control, semen was diluted and frozen in the diluent without BHT. Motility, progressive motility, viability, membranes and acrosome integrity were evaluated after dilution (part 1), cooling (part 2) and freezing and thawing (part 3). The results of the first part of the experiment showed that there were no significant difference between treatments in the motility, progressive motility, viability, membranes and acrosome integrity of spermatozoa, but the results with 2.0 mM BHT were slightly better than obtained with other levels of BHT and control extender. Significantly better results (p<0.05) were observed in the second part of the experiment for cooled spermatozoa characteristics, when extender was supplemented with 2.0 and 3.0 mM BHT. Furthermore, the results obtained in the third part of the experiment indicated that, after freezing and thawing, all evaluated semen characteristics were improved significantly (p<0.05) by increasing BHT levels, with the best results obtained for extender containing 2 mM BHT. Comparison of these results with those of control diluent, the effects of supplementation were significantly (p<0.01) better. However, the higher concentration of BHT (3.0 mM) reduced the motility, acrosomal integrity, viability and hypo-osmotic swelling response of spermatozoa compared to extender containing 2.0 mM BHT. In conclusion, the results obtained in this study showed that the semen quality of rams was improved when BHT was added to extender used before the freezing process.

• Journal of Veterinary Clinics
• /
• v.34 no.2
• /
• pp.156-160
• /
• 2017

We investigated the effect of ethylene glycol and antioxidants such as taurine, hypotaurine and trehalose with extenders during cryopreservation of Korean Jeju Black Bull spermatozoa. The cryopreservation of freshly collected spermatozoa was conducted with four different conditions. As a control, spermatozoa were cryopreserved with Tris egg-yolk extenders added 5% ethylene glycol (EG). Taurine (20 mM), hypotaurine (20 mM) and trehalose (20 mM) were individually added into tris egg-yolk extenders with 5% EG. After thawing of frozen spermatozoa with four different conditions, sperm viability, motility, acrosomal integrity, and membrane integrity were investigated. The significant (p < 0.05) improvement of sperm viability showed in all antioxidant treated thawed spermatozoa (taurine; $68.1%{\pm}4.4$, hypotaurine; $69.2%{\pm}6.7$ and trehalose; $68.0%{\pm}4.4$) when compared to control ($63.4%{\pm}5.6$). Neither positive nor detrimental effects of three antioxidants were shown sperm motility after thawing. The results of hypo-osmotic swelling test showed that the membrane integrity of taurine, hypotaurine or trehalose treated thawed spermatozoa ($64.1%{\pm}5.4$, $61.5%{\pm}3.7$ and $59.0%{\pm}4.0$, respectively) had significantly (p < 0.05) higher rate of the swollen sperm compared to control ($53.7%{\pm}9.7$). Hypotaurine treated frozen-thawed spermatozoa had siginificantly higher (p < 0.05) F pattern ratio than taurine, trehalose and control treated frozen-thawed spermatozoa. Trehalose added frozen-thawed spermatozoa had significantly higher (p < 0.05) acrosome reaction pattern ratio than taurine and hypotaurine added frozen-thawd spermatozoa. In this study, we found that antioxidants such taurine, hypotaurine and trehalose treatments during cryopreservation process could reduce damage of spermatozoa of Korean Jeju Black Bull and improved sperm capability of fertilization.