• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.139-148
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• 2012

Purpose : Since standard solution is the one that knows its exact concentration, the curve of the dissolution has been determined according to the amount of the solution, compared to the amount of the unknown sample. Therefore, the antigen that makes up standard materials should be made in a pure form. The configuration of the standard substance solution in the kit we use is a freeze-dried material, or made and comes as a liquid. Lyophilized reference material is used after dissolving in usually D.W. (Distilled Water), and if the antigen to use is too sensitive, reagents should be freeze-dried. Furthermore, when freeze-dried reference has to be frozen again after being dissolved, it should be kept under $-20^{\circ}C$ until the expiration date according to the reports. Since it is not expressed in the experiment if it is safe or stable to reuse the solution which was dissolved a few times, thus, this time it is tested and evaluated that the changes of the standard solution by freezing and melting several times, and its results and the effectiveness of it were compared to the solution which was kept in a fridge. Materials and Methods : Among Vitro diagnostic kits on the market made by radioimmunoassay, parathyroid hormone (PTH), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH) are made of freeze-dried standard solution and all composed of the same Lot.NO. These hormones melted in D.W. and were separated into three groups. In the first group, melting and freezing were repeated, and in the second group, The solution only for one time use was put into a test tube after melting and freeze it. The third group was kept in the refrigerator. This experiment has been conducted from January to February in 2012. January to 2012. PH test was employed because ph is prone to changing depending on the change of protein. Each group of the standard solution, cpm (counter per minute), and the patient relative concentration values were compared by date, and Through the correlation coefficient and Paired t-test, the significant level of each group was analyzed. Results : ACTH, PTH, LH pH values were too subtle denaturation rather than numerical changes in the protein. In addition, when the standard solution of ACTH, PTH, LH was refrigerated, after 3 days and 7 days, there was a significant difference observed between the solution being kept in a refrigerator and a freezer within a significance level. Conclusion : Standard solution should be kept in a freezer, and being kept in a fridge, it is recommended to use the solution as soon as possible.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1656-1663
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• 2009

The antioxidant activities of water extracts from wild vegetables such as Ligularia fischeri (GC), Capsicum annuum L. (GCY), Aster scaber (CNM), Petasites japonicus S. et Z. Max (MYD), Ipomoea batatas L. (Lam) (GGM) were evaluated and compared with water extracts from freeze dried block. The antioxidant properties of water extracts from wild vegetables and their freeze dried block were evaluated using different antioxidant tests; 2.2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, hydroxyl radical scavenging and nitrite scavenging activities. The water extracts from wild vegetables were found to have a higher total phenolic content than water extracts from freeze dried block. Total phenolic contents of water extracts from GC, GCY, CNM, MYD, and GGM were $471.66{\pm}3.52\;{\mu}g/mg,\;141.33{\pm}2.51\;{\mu}g/mg,\;177.33{\pm}2.88\;{\mu}g/mg,\;238.66{\pm}9.50\;{\mu}g/mg\;and\;122.67{\pm}3.51\;{\mu}g/mg$, respectively. At the concentrations of 1000 ppm, water extracts from GC, GCY, CNM, and GGM showed higher activities than water extracts from their freeze dried block on DPPH radical scavenger activity. The activity of water extracts from CNM, GC, GCY, MYD, and GGM were 90.9%, 89.9%, 76.6%, 71.1%, and 57.4%, respectively. When 10000 ppm of GC, GCY, CNM, MYD, and GGM water extracts tested for hydroxyl radical scavenging activity, activities were increased by 38.8%, 33.4%, 35.9%, 34.3%, and 33.8%, respectively and a similar effect was found with water extracts from GCY, CNM, and GGM freeze dried block at 10000 ppm concentration. However, the water extracts from GC and MYD was slightly more effective than freeze dried block extracts. The water extracts from wild vegetables and their freeze dried block had effective DPPH radical scavenger activity and hydroxyl radical scavenging activity at all tested concentrations. Nitrite scavenging activity of GC water extract significantly increased in a dose-dependent manner and the extract had higher nitrite scavenging activity than extracts freeze dried block extracts. We found that freeze dried block maintained antioxidant activities of the wild vegetables.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.667-674
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• 2013

This study was aimed to investigate the effect of microwave-assisted extraction on Schizandra fruit extract dried by two different treatments: freeze-drying and hot air-drying. Two extraction parameters were measured in particular: total polyphenol content and antioxidant activity. Both values were found to increase as the microwave power increased, for both drying processes. However, the extract from the freeze-dried sample exhibited higher antioxidant activity than that from the hot air-dried samples. Additionally, the total polyphenol content and antioxidant activity of the extract from the freeze-dried samples increased with the extraction time, whereas they decreased with the extraction time in the case of the hot air-dried sample. Solvent concentration was also found to have a significant effect on total polyphenol content and antioxidant activity; the highest values for both properties were achieved at 50 and 70% ethanol concentrations, respectively. In summary, a higher total polyphenol content and antioxidant activity were observed for Schizandra fruit extracted by freeze-drying than that by hot air-drying.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.397-406
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• 1998

Hen egg white lysozyme (HEWL) is very valuable as a natural preservative in food processing due to its selective bactericidal activity. HEWL which traditionally isolated by crystallization or freeze drying was simply separated from 13 different hen egg white (HEW) proteins by a single-step ultrafiltration. Freeze dried HEW (0.25%, w/v) dissolved in a citrate-phosphate buffer (pH 4.6) was ultrafiltered with a PM30 membrane under various operating conditions, by changing concentration, temperature, transmembrane pressure $({\triangle}P_T)$, and stirring speed. Optimum separation conditions were decided when maximal flux was obtained. Under the optimum separation conditions, the effect of membrane material and fouling on flux as time passed as well as lysozyme concentration, protein concentration, specific activity (SA) in the permeate were measured. Best separation conditions of HEWL with PM30 membrane were sample concentration 0.25%, temperature $35^{\circ}C$, ${\Delta}P_T\;30\;psi$, and stirring speed 300 rpm. During the first 12 min, the flux of YM30 was higher, but at the steady-state it was lower than that of PM30. The SA of the PM30 permeate was over 2 times higher in spite of the lysozyme and protein concentration being lower than that of YM30 permeate. The flux of 5 times used PM30 decreased 30% compared to a new PM30, but both had the same tendency in flux decrease when time passed. Both of them reached a steady-state after 35 min and remained at 70% of the initial flux. In the PM30 permeate, the lysozyme concentration and SA were 110 units/mL and 2,821 units/mg protein, respectively. Therefore, PM30 membrane separation was very effective for separation of antimicrobial lysozyme.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.111-115
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• 2009

Carrots were dried using 30, 50, and 80% polyethylene glycol (PEG) or maltodextrin as a dehydrating agent, and the dried carrots were compared with the freeze dried and hot-air dried in terms of rehydration ratio, color, carotene content, and sensory evaluation. The amount of moisture loss during drying of carrots using PEG or maltodextrin increased with increasing concentration of dehydrating agent. Rehydration ratio as well as carotene content of the PEG-treated carrots were greater than those of freeze-dried or hot-air dried carrots. Regarding color and sensory evaluation of the dried carrots, the PEG-treated and maltodextrin-treated carrots were better than freeze-dried or hot-air dried carrots. These results suggest that drying of carrots using PEG or maltodextrin is a very efficient method because of its good rehydration capacity and minimal destruction of nutrients and cell structure.

• Textile Coloration and Finishing
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• v.21 no.1
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• pp.10-20
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• 2009

The objective of this study is to investigate the efficacy of leaf powder colorants as substitutes for traditional fresh juice extract dyeing. Three kinds of leaf powder colorants were prepared by freeze drying method with or without deep freezing as pre-treatment: one powder colorant from fresh leaf juice with deep freezing; two kinds of powder colorant from fresh leaves with and without deep freezing. Their dyeing properties and storage stabilities were studied and compared with the traditional fresh juice extract dyeing. The presence of indigo in the powder colorants was confirmed by UV/Visible absorption spectra. They showed absorption peak at 602nm which was same with indigo absorption peak. Dyeing was done at low temperature around 6$^{\circ}C$. All three powder colorants produced B colors on silk fabrics, showing similar color to the one dyed traditionally with fresh juice extract. The powder colorants from leaves gave higher color strength than the powder from leaf juice. The powder colorant prepared from leaves with deep freezing was the most stable for long term storage as its color and color strength were not changed after 360 days. So, this was used for further dyeing to study the effects of concentration and repeat dyeing on color strength and colorfastness. Fastnesses to dry cleaning and rubbing were fairly good above 4 rating. Further study is needed to improve light fastness. It was concluded that the leaf powder colorant with deep freezing could be used as a substitute for traditional juice extract dyeing at all seasons.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.157-166
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• 2021

The probiotic market is constantly continuing to grow, concomitantly with a widening in the range and diversity of probiotic products. Probiotics are defined as live microorganisms that provide a benefit to the host when consumed at a proper dose; the viability of a probiotic is therefore of crucial importance for its efficacy. Many products undergo lyophilization for maintaining their shelf-life. Unfortunately, this procedure may damage the integrity of the cells due to stress conditions during both the freezing and (vacuum-) drying process, thereby impacting their functionality. We propose a lysine-based mixture for rehydration of freeze-dried probiotics for improving their viability during in vitro simulated gastric and duodenum stress conditions. Measurement of the zeta potential served as an indicator of cell integrity and efficacy of this mixture, while functionality was estimated by adhesion to a human enterocyte-like Caco-2 cell-line. The freeze-dried bacteria exhibited a significantly different zeta potential compared to fresh cultures; however, this condition could be restored by rehydration with the lysine mixture. Recovery of the surface charge was found to influence adhesion ability to the Caco-2 cell-line. The optimum lysine concentration of the formulation, designated "Zeta-bio", was found to be 0.03 M for improving the viability of Lactiplantibacillus plantarum Lp-115 by up to 13.86% and a 7-strain mixture (400B) to 41.99% compared to the control rehydrated with distilled water. In addition, the lysine Zeta-bio formulation notably increased the adherence ability of lyophilized Lp-115 to the Caco-2 cell-line after subjected to the in vitro stress conditions of the simulated gastrointestinal tract passage.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.107-113
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• 2010

In this study, the relative effects of low-chloride deicier(LCD) and two other deicing agents on the scaling of concrete were conducted in a series of tests at laboratory accordance with the ASTM C 672. The solutions concentration of deicers tested included 1, 4, 10%. Tap water was used as control. The amount of scaling was evaluated gravimetrically. As test result of deicer solution types, when applied to 4% solutions, surface scaling of concrete after 56 freeze-thaw cycles was produced significantly as about 9 times on LCD solution, as about 18 times on $CaCl_2$ solution, and as about 33 times on NaCl solution comparing with tap water. As test result of deicer solution concentrations, relatively low concentrations (of the 4% by weight) of deicer were produced more surface scaling than higher concentrations (of the 10% by weight) or lower concentrations (of the 1% by weight) of deicer. It show that the damaging concentration is of the order of 3~4% for previous research result. It appears that the mechanism of surface scaling is primarily physical rather than chemical. Also, the effect of chloride deicier types, freeze-thaw cycling, and air contents on the performance of concrete was experimentally investigated. The results show that the concrete specimens subjected to freeze-thaw cycling scaled more severely in exposure to deicing salt than those in non-exposure to deicing salt, weight losses of the specimens tested in exposure to deicing salt were twice as much as those tested in non-exposure to deicing salt. Relative dynamic modulus of elasticity of concrete specimens decreased more quickly in exposure to deicing salt than in non-exposure to deicing salt. Also, relative dynamic modulus of elasticity of concrete specimens in exposure to sodium chloride deicing salt was decreased more quickly comparing with exposure to LCD salt. It is also shown that the chloride contents according to concrete specimen depths was more largely in exposure to LCD salt. When concrete specimen is exposed to chloride deicing salts and freeze-thaw cycling, performance degradation in the entrained air concrete(AE concrete) retarded more considerably comparing with non-entrained air concrete(Non-AE concrete).

• BMB Reports
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• v.28 no.2
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• pp.129-137
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• 1995

The ryanodine-receptor $Ca^{2+}$ release channel protein in the sarcoplasmic reticulum membrane of rabbit skeletal muscle plays an important role in muscle exitation-contraction (E-C) coupling. Various types of detergents were tested, including Chaps, cholate, octylglucoside, Zwittergents, Mega-9, Lubrol PX, and Triton X-100 for solubilization of this protein. Among these, Chaps and Triton X-100 were found to optionally solubilize the channel complex. Optimum conditions for this solubilization were pH 7.4 with a salt concentration of 1 M. The addition of phospholipid in the solubilization step helped in stabilizing the protein. The purification of the receptor was performed using sucrose density gradient centrifugation. Various methods [dilution, freeze-thaw, adsorption (Biobeads), and dialysis] were investigated to incorporate the Chaps-solubilized and purified $Ca^{2+}$ release channel protein into liposomes made from different types of phospholipids. Of these, a combined method consisting of a dialysis, freeze-thaw and sonication steps yielded the best results. Reconstituted vesicles produced by this method with 95% phosphatidylcholine (from soybean extract) had good function.

• Journal of Powder Materials
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• v.18 no.4
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• pp.327-331
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• 2011

In order to fabricate the porous metal with controlled pore characteristics, unique processing by using metal oxide powder as the source and camphene as the sublimable material is introduced. CuO powder was selected as the source for the formation of Cu metal via hydrogen reduction. Camphene-based CuO slurry, prepared by milling at $47^{\circ}C$ with a small amount of dispersant, was frozen at $-25^{\circ}C$. Pores were generated subsequently by sublimation of the camphene. The green body was hydrogen-reduced at $200^{\circ}C$ for 30 min, and sintered at $500-700^{\circ}C$ for 1 h. Microstructural analysis revealed that the sintered Cu showed aligned large pore channels parallel to the camphene growth direction, and fine pores are formed around the large pore. Also, it showed that the pore size was controllable by the slurry concentration.