• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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• pp.1716-1721
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• 2006

The present study was conducted to observe the effect of osmolality of glycerolated TEST-yolk glycerol extenders on post-thawing sperm kinematics of ram spermatozoa of the native Malpura breed maintained in a semi-arid tropical environment. Good quality semen obtained from adult rams was pooled, split and diluted to 1,000 million spermatozoa per ml in complete TEST-yolk-glycerol extenders of 900, 1,200, 1,500 and 1,800 mOsm/kg osmolality. Diluted semen samples were loaded in 0.25 ml straws and cooled down to $-125^{\circ}C$ freezing temperature at the rate of $-25^{\circ}C$ per minute under controlled conditions before plunging into liquid nitrogen for storage. The thawing of straws was performed at $50^{\circ}C$ in a water bath for 10 seconds and sperm kinematics of the frozen-thawed spermatozoa were assessed by a computer-assisted sperm analysis technique. Osmolality of diluent had no significant effect on post-thawing % motility, % rapid, % medium and % slow moving frozen-thawed spermatozoa but significantly (p< 0.05) affected the % linearity and % straightness. The post-thawing % motility and % rapid motile spermatozoa were highest in samples extended in diluent of 1,500 mOsm/kg osmolality and lowest in 900 mOsm/kg. The curvilinear velocity of spermatozoa was significantly (p<0.05) higher for samples extended in 1,800 mOsm/kg, compared to those in 900 and 1,200 mOsm/kg, but the effect was not significantly different to those extended in diluent of 1,500 mOsm/kg osmolality. The study indicated that ram spermatozoa could tolerate a wide osmolality range for dilution in the complete TEST-yolk-glycerol extender for their cryosurvival. The highest recovery of motile spermatozoa following thawing was achieved in samples extended in the TEST-yolk-glycerol diluent of 1,500 mOsm/kg osmolality.

• Fire Science and Engineering
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• v.31 no.6
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• pp.1-7
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• 2017

Currently, flammable liquids account for more than 87 wt% of the hazardous materials in circulation in Korea, and paint products are the most commonly used mixed hazardous materials. Therefore, one of the most urgent and important issues is that we have to secure the safety for manufacturing, storage and transport of paint products. In this study we investigated and analyzed the domestic hazardous materials safety management method, the international GHS test method and so forth. We tested risks for a variety of oil paints and found a relation between the results. Furthermore, the risk test method and criteria adapted for domestic situation was presented. Paints were classified as hazardous or non-hazardous according to the results of the flash point test, the amount of flammable liquid or the UN-combustion persistence test. It was revealed from the test results of 6 kind of oil-based paints using different resins that they were hazardous materials with very high risks and belonged to the Category 1 or the Category 2.

• Journal of Biosystems Engineering
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• v.40 no.3
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• pp.271-276
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• 2015

Purpose: Quick freezing is widely used in commercial food storage. Well-known freezing techniques such as individual quick freezing require a low-temperature coolant and small cuts for the heat-transfer efficiency. However, the freezing method for bulk food resembles techniques used in the 1970s. In this study, electromagnetic (EM) heating was applied to improve the quick freezing of bulk food. Methods: During freezing, the surface of food can be rapidly cooled by an outside coolant, but the inner parts of the food cool slowly owing to the latent heat from the phase change. EM waves can directly heat the inner parts of food to prevent it from freezing until the outer parts finish their phase change and are cooled rapidly. The center temperature of garlic cloves was probed with optical thermo sensors while liquid nitrogen (LN) was sprayed. Results: When EM heating was applied, the center cooling time of the garlic cloves from freezing until $-10^{\circ}C$ was 48 s, which was approximately half the value of 85 s obtained without EM heating. For the white radish cubes, the center cooling time was also improved, from 288 to 132 s. The samples frozen by LN spray with EM heating had a closer hardness to the unfrozen samples than the samples frozen by LN only. Conclusions: The EM heating during quick freezing functions to maintain the hardness of fresh food by reducing the freezing time from 0 to $-10^{\circ}C$.

• Journal of Pharmaceutical Investigation
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• v.28 no.2
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• pp.121-126
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• 1998

The solubility and physicochemical stability of caroverine hydrochloride (CRV), an antispasmodic, in buffered aqueous solutions were studied using a reverse phase high performance liquid chromatography. The solubilty of the drug at pH 2.76-5.40 was similar at the range 31.9-36.2 mg/ml $(34^{circ}C)$, but, at the pH higher than 6.0, markedly decreased. The use of polyethylene glycol 400 as a cosolvent did not increase the solubility at any compositions examined. Moreover. increasing molar concentration of aqueous phosphate buffer from 0 to 0.5 M remarkably decreased the solubility. The degradation of CRY followed the apparent first-order kinetics. The degradation was accelerated with decreasing pH and increasing storage temperature. The half-lives for the degradation of CRY (1.0 mg/ml) at pH 1.28. 4.01 and 5.93 $(45^{\circ}C)$ were 2.8, 31.4 and 124 hr. respectively. The pHs of incubated solutions were to some extent lowered perhaps due to the formation of acidic degradation products. The addition of disodium edetate (0.01%) to the CRY solution (pH 4.95) retarded 2.5 times the degradation rate at $45^{\circ}C$, but the use of sodium bisulfite (0.1%) accelerated 2.9 times the rate. The activation energy for the CRY solution (20 mg/ml. pH 5.4) containing 0.01% EDTA was calculated to be 5.98 kcal/mole. When the solution was stored under nitrogen displacement in ampoule, there was no significant degradation even after 3 months at $40^{\circ}C$, indicating that protection from oxidation by air (oxygen) is essential for the complete stabilization of CRY solution.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.73-77
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• 1992

The effect of a nisin-producing Lactococcus lactis spp. lactis (L. lactis) on the growth and attachment of Listeria monocytogenes Scott A and Brie 1 on stainless steel and their growth in Brain Heart Infusion broth was determined. Viable cells of Listeria decreased rapidly after 9~12 hr of incubation at $21^{\circ}C$ and after 6~9 hr of incubation at $32^{\circ}C$ in the presence of L. lactis. The number of L. monocytogenes Scott A attached to stainless steel in pure culture was $2.5{\times}10^3/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}2.3{\times}10^3/\textrm{cm}^2{\;}at{\;}32^{\circ}C$ after 48 hr of incubation, but was only $10/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}1.1{\times}10/\textrm{cm}^2{\;}at{\;}32^{\circ}C$ in the presence of L. lactis. Results from L. monocytogenes strain Brie 1 were similar to those from strain Scott A. The population of L. monocytogenes Scott A which attached to stainless steel with previously adherent L. lactis was $1.8{\times}10^2/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}8.2{\times}10^2/\textrm{cm}^2{\;}at{\;}32^{\circ}C$, whereas the population attached to sterile stainless steel was $1.2{\times}10^3/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}2.1{\times}10^2/\textrm{cm}^2{\;}at{\;}32^{\circ}C$. For L. monocytogenes Brie 1, the attached population of the control was $1.6{\times}10^4/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}3.2{\times}10^2/\textrm{cm}^2{\;}at{\;}32^{\circ}C$, and on stainless steel with adherent L. lactis, it was $1.1{\times}10/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}6.9{\times}10/\textrm{cm}^2{\;}at{\;}32^{\circ}C$. Surface adherent L. lactis was less inhibitory to attachment of L. monocytogenes on stainless steel than a liquid culture inoculum. Listeria attached to stainless steel survived dry storage for 20 days both in the presence and absence of adherent lactococci.

• Polymer(Korea)
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• v.24 no.5
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• pp.589-598
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• 2000

In this study, various unsaturated polyester (UPE) resins were prepared from the condensation polymerization of mixtures of saturated (isophthalic acid : IPA) and unsaturated (maleic anhydride : MA) dibasic acids with propylene glycol (PG), neopentyl glycol (NPG). The critical surface tension (Υ$_{c}$) for the surface characteristics of a solid were estimated by Zisman plot, and the structure-property relationship was investigated by measuring the rheology of resins. The values of Υ$_{c}$ for glass of solid were 30.5 mNㆍm$^{-1}$ for UPE resin liquids. As the content of NPG in a PG/NPG glycol mixture increased, both the contact angle and the surface tension of the UPE resin liquids were found to decrease. The dynamic viscoelasticities of UPE resins with different glycol molar ratios were also measured. Shear rate dependence of viscosity and angular frequency dependence of storage, and loss modulus tended to decrease with increasing NPG content.

• Nuclear Engineering and Technology
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• v.6 no.2
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• pp.97-111
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• 1974

The adsorption mechanism of Cs-137 in low level radioactive solution by vermiculite treated with Na ion is studied in order to investigate its effective utilization for the radioactive effluent treatment. The beneficial role of Na-vermiculite is that Na ion can induce the wider c-axis spacing in which Cs ion can be sorbed in vermiculite. Cation exchange capacity and distribution coefficient of cesium seems to be influenced by the variation of c-axis spacing of vermiculite. Comparative identification and detection with the characteristic analyses of X-ray diffraction and electron diffraction patterns, diffrential thermal analysis and electron microscopy of Na-, K- and Cs-vermiculite are studied for the phemomena of Cs adsorption by vermiculite. This importance of the utilization in terms of adsorption and fixation of cesium involving vermiculite is discussed. It is found that the Na-vermiculite is valuable outside charging material for high level radioactive liquid waste storage tank of underground to protect the pollution of the underground water.

• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.196-203
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• 2008

Hwangtae, dried Alaska pollack, is a major storage product in the fish processing industry. Hwangtae is prepared by removing the internal organs and drying outdoors during the cold witner months by allowing it to thaw during the daytime and re-freeze at night under sub-zero ($-10^{\circ}C$) conditions and gradually dry from December until the next April for around 5 months from Myungtae. In this study, ground Hwangtae was hydrolyzed using two proteolytic enzymes (pepsin and alcalase) which produced five soluble active peptides from Hwangtae (yellowish dried Pollack, Theragra chalcogramma) protein. Two different peptides with strong antioxidative activity were isolated from the hydrolysate using consecutive chromatographic methods of Sephadex G-25 gel, ion-exchange chromatography on a Sepharose-Sephadex C-25 gel, and high-performance liquid chromatography. The isolated peptides, APO1 and APO2, were composed of 16 and 13 amino acid residues, respectively. Both peptides contained a Gly residue at the C-terminus and the repeating motif Gly-Pro-Hyp. The peptide with a molecular weight less than 1,000 Daltons (APACE) obtained from enzymatic hydrolysates of Hwangtae exhibited the highest ACE inhibitory activity. The APACE peptides was composed of 4 amino acid residues (Gly-Leu-Leu-Pro). These results suggest that Hwangtae hydrolysates could be a good source of peptides with ACE inhibitory activity. Biochemical analysis indicated that two 70 kDa peptides (APG1 and APG2) isolated from the hydrolysate had gelatinoytic activity, which was shown to be a calcium dependent protease type as showed by gelatin SDS PAGE.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.3
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• pp.225-231
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• 2013

Oil in water nanoemulsion of astaxanthin was prepared by high pressure homogenization. The emulsifying conditions including emulsifier type, concentration and astaxanthin concentration were optimized. Stability of nanoemulsion was measured using zetasizer, freeze-fracture scanning electron microscope (FF-SEM), particle analyzer and colorimeter. The mean diameter of the dispersed particles containing astaxanthin ranged from 160 to 190 nm. Size distribution was unimodal and extended from 40 to 200 nm. The nanoemulsion prepared by glyceryl citrate/lactate/linoleate/oleate had smaller particle size and narrow size distribution. Stable incorporation of astaxanthin in nanoemulsion was performed and checked using high performance liquid chromatography (HPLC), freeze-fracture scanning electron microscope (FF-SEM). Physical stability of nanoemulsion was not significantly changed during storage at both light and thermal condition for a month with zeta potential value of -41 mV meaning stable colloid.

• Korean Journal of Plant Resources
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• v.28 no.6
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• pp.697-703
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• 2015

Twenty apple germplasm accessions from the Korean Genebank were successfully cryopreserved using two-step freezing to back up genetic resources maintained by field collections. This study examined the morphological and genetic stability of cryopreserved dormant apple buds that were stored in liquid nitrogen, and then rewarmed and regrown. Whole plants were regenerated directly from dormant buds through budding without an intermediary callus phase. The cryopreserved buds produced high levels of shoot formation (76.2-100%), similar to those of noncryopreserved buds (91.3-100%), with no observed differences between cryopreserved and noncryopreserved materials. Three of the twenty cryopreserved apple germplasm accessions were used to assess morphological and genetic stability. No differences in morphological characteristics including shoot length, leaf shape, leaf width/length ratio, and root length were observed between controls (fresh control and noncryopreserved) and cryopreserved plantlets. The genetic stability of regenerants (before and after cryopreservation) was investigated using inter simple sequence repeat (ISSR) markers. The ISSR markers produced 253 bands using four primers, ISSR 810, SSR 835, ISSR 864, and ISSR 899. These markers showed monomorphic banding patterns and revealed no polymorphism between the mother plant and regenerants before and after cryopreservation, suggesting that cryopreservation using two-step freezing does not affect the genetic stability of apple germplasm. These results show that two-step freezing cryopreservation is a practical method for long-term storage of apple germplasms.