• Journal of the Korean Ceramic Society
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• v.24 no.1
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• pp.77-85
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• 1987

Hardened cement paste is mainly affected by corrosion of sulphate and chlorine ions in sea water. In this investigation, many specimens were made with the cement clinker minerals such as C3S, C3A, C4AF and their mixture according to cement composition added various blending materials. After the specimens were immersed in 4% MgSO4 and MgCl2 solutions, the product of reaction, the microstructure of specimen and Ca+2 ion leached in the solution were studied. The formation of Ca(OH)2 in the specimen of C3S is reduced relatively by adding pozzolanic admixtures. The chlorine ion is easily diffuse into the C3S specimen and produced CaCl2 compound, and it makes the specimen porous by leaching out itself into the solution. The specimen of C3A, C4AF are broken down by expanding reaction of ettringite and gypsum compound produced in the MgSO4 solution. At a later period, the ettringite is transformed into gypsum and 5MgO.2Al2O3·15H2O. The C3A in the MgCl2 solution combines chlorine ion to form Friedel's salt and prevents the diffusion reaction of chlorine ion into the specimen. Granulated slag shows inferior effect on the resistance of the specimen in MgSO4 solution by forming ettringite and gypsum, but good result in MgCl2 solution. Pozzolanic materials, on the whole, offer noticable effect on the resistance of the specimen in both solutions.

• Microbiology and Biotechnology Letters
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• v.25 no.4
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• pp.346-353
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• 1997

During the screening of cellulase producing microorganisms, a fungal strain C-4 was selected from etiolated leaves. Based on taxonomic studies, the fungus could be classified as a strain of Trichoderma sp. When the strain C-4 was cultured in Mandels' media at 28$circ$C for 6 days, the enzyme activities detected in broth were as follows: 8.2 U/ml (28.1 U/mg) of CMCase activity, 0.75 U/ml (2.58 U/mg) of Avicelase activity, 1.67 U/ ml (5.68 U/mg) of $eta$-glucosidase activity. The optimum pH for enzyme induction was 6.2. The crude enzyme retained 100% of its original CMCase activity at 50$circ$C for 1 hr (pH 5.0), and at 4$circ$C for 24 hrs (pH 5.0). There was no effect on the CMCase activity in the presence of 1 mM of CsCl, LiCl, MgCl$_{2}$, and FeCl$_{2}$, respectively. When the crude enzyme was treated with trypsin and chymotrypsin (2% W/w) for 10 minutes, the remaining CMCase activity was 70%, but there was no further loss of activity for 60 minutes treatment at 30$circ$C. The crude enzyme showed the synergism with rumen fluid for the hydrolysis of Avicel and CMC by 118% and 130%, respectively.

• Journal of Ecology and Environment
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• v.31 no.4
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• pp.341-344
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• 2008

We investigated the responses of red squirrels to pine nuts (Pinus koraiensis) treated with Lithium Chloride (LiCl) and the potential of the chemical for inducing conditioned taste aversion (CTA) in red squirrels. In red squirrels, nut feeding declined dramatically during the first 4 days after feeding with LiCl-treated nuts. The ratio of LiCl-treated nuts eaten to total nuts eaten declined from the $1^{st}$ day in LC-1 and the $2^{nd}$ day in LC-2, along with a general reduction in quantity eaten. Thus, feeding with LiCl-treated nuts induced CTA from the 2nd day after feeding, and CTA remained constant until the $4^{th}$ day, but disappeared on the $5^{th}$ day. The squirrels ate an average of $757.0{\pm}106.1mg$ (n = 2, range $682.0\sim832.0$) of LiCl before dying on the $16^{th}$ day of the study. The lethal dose of LiCl was 2.32 mg LiCl/g body weight, and the average amount of LiCl needed to induce CTA was $23.0{\pm}4.24mg$ (20 mg in LC-1 and 26 mg in LC-2).

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.146-152
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• 2005

The objective of present study was to investigate the effect of onion extracts on mercuryinduced cytotoxicity, lipid peroxidation and antioxidant enzyme activities in primary monolayer cultures of rat hepatocytes. Primary cultures of rat hepatocytes were incubated for 6 hr in the presence of various concentrations (0, 1, 5, 10, 30 or 50 ppm) of $HgCl_2$. Cytotoxicity and cell viability were determined by measuring glutamic oxaloacetic transaminase (GOT) activity, lactate dehydrogenase (LDH) activity and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) value. Lipid peroxidation w as evaluated using thiobarbituric acid reactive substances (TBARS) assay. Effects of onion extract on antioxidant system were determined by measuring catalase, glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Rd) activities as well as DPPH free radical scavenging activity. $HgCl_2$ at the concentration of 10 ppm increased GOT activity and TBARS concentration but decreased %MTT reduction, whereas $HgCl_2$ at the concentration of 30 ppm increased LDH activity, representing that $HgCl_2$ caused cytotoxicity and lipid peroxidation in dose-dependent manner, $HgCl_2$ at the concentration of 30 ppm significantly decreased catalase, GSH-Px and GSH-Rd activities. When primary cultures of rat hepatocytes were incubated with various concentrations (0, 0.01, 0.05, 0.1 or 0.3 mg/ml) of onion extract for 6 hr in the presence of 30 ppm of $HgCl_2$, onion extracts at the concentration of 0.05 mg/ml decreased GOT activity, but increased %MTT reduction by 30 ppm of $HgCl_2$. $HgCl_2-induced$ LDH activity and TBARS concentration were decreased by onion extract at the concentration of 0.01 mg/ml. Taken together, onion extract prevented H$HgCl_2-induced$ hepatocyte injury and lipid peroxidation. Onion extracts at the concentration of 0.1 mg/ml almost or completely inhibited $HgCl_2-induced$ catalase and GSB-Px activities. GSH-Rd activity, however, was not affected by onion extract. Free radical scavengjing activity was increased as concentration of onion extract increased. Onion extract at the concentrion of 5 mg/ml possesed mote than 93% scavenging activity comparing to 100% radical scavenging activity by pyrogallol solution as a reference. These results demonstrate that onion extracts suppressed mercury-induced cytoctoxicity and lipid peroxidation by scavenging free radical and increasing catalase and GSH-Px activities.

• Korean Journal of Microbiology
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• v.24 no.4
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• pp.364-369
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• 1986

A procedure for the preparation, regeneration and fusion of protoplasts of Streptomyces tubercidicus was confirmed. Also, protoplast releasingprocesses from mycelia were observed by scanning electron microscope. Three types of protoplasts releasing processes-from the hyphal tip, hyphal end regions and lateral regions of the hyphae-were observed. More than 17% regeneration efficiency was obtained by regeneration medium that is composed of tryptone-yeast extract-sodium acetate-$MgCl_2-CaCl_2$-sucrose. Optimal concentrations of $Ca^{++},\;Mg^{++}$ and sucrose in the regeneration medium were 50mM, 0.4-0.5M respectively. Above 30% of fusion frequency of the protoplasts derived from two auxotrophic strains of S. tubercidicus was induced by polyethylene glycol 4000(60% w/v).

• Applied Microscopy
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• v.30 no.4
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• pp.389-401
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• 2000

The mouse for identifying the histological changes of kidney were also divided into the two groups; treated with only $HgCl_2$ (4 mg/kg), the group treated with $HgCl_2$ and squalene (200 mg/kg). The $HgCl_2$ treated only one time at first day. The squalene treated two times a day (12 hours interval) for every day. Each groups were divided into the five groups; 6, 12, 24, 48 and 72 hours after treated $HgCl_2$ and squalene. Historical changes of the kidneys were investigated by electron microscope. The group with only $HgCl_2$ showed that the nuclear membrane was shrinked, the inner membrane (cristae) of the mitochondria were destructed, and ribosomes on the rough endoplasmic reticulum were lost. The group treated with $HgCl_2$ and Squalene showed that the nuclear membrane was more rounded, the cristae of the mitochondria were almost normal shape, and more ribosomes on the rough endoplasmic reticulum were attached. Therefore , we concluded that squalene has significantly protective effects in kidney to harmful $HgCl_2$.

• Applied Microscopy
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• v.31 no.2
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• pp.175-184
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• 2001

This study aims demonstrate the effect of chitosan, one of the natural chelator, on the ultrastructural changes in the mouse liver caused by $HgCl_2$. The experimental group was divided in two groups; group A and group B. The group A administrated $HgCl_2$ (5.0 mg/kg) to the oral. The group B treated with $HgCl_2$ (5.0 mg/kg) and chitosan (3%) solution, 2 times/day). Each group was observed 24, 48, 72 and 96 hours after treated $HgCl_2$ and chitosan. Histological changes of the livers were investigated by electron microscope. 1. Croup A Nuclear membrane was shrinked. The inner and outer membrane of the mitochondria were dilated. Destruction of lamellae of rough endoplasmic reticulum showed. Smooth endoplasmic reticulum showed over cytoplasm. 2. Group B Nuclear membrane was more rounded, The cristae of the mitochondria were almost normal shape and electron-density showed compacted. Dilation of inner cavity of rough endoplasmic reticulum showed at the pre-time but formed typical lamellae at the 48Hrs. Smooth endoplasmic reticulum showed over cytoplasm. Therefore, we concluded that chitosan has significantly protective effects in liver to harmful $HgCl_2$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.231-238
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• 1983

An investigation on optimum condition for processing of salted-dried sardine and quality change of the product during the storage was carried out. The fillets of sardine were salted in 5, 10 and $15\%$ NaCl solution for 12, 24 and 36 hours at $9-10^{\circ}C$, respectively and air-blast dried at $24-25^{\circ}C$ with a velocity of 3 m/sec and then stored at room temperature for 30 days. The results were as follows : The optimum condition for the product was salting in $15\%$ NaCl solution for 36 hours as VBN and histamine contents were 27.5 mg/100g and 42.5 mg/100g, respectively, and also showed a good result in sensory evaluation. Histamine, VBN and TMA-N content of the dried fillets immediately after salting in $15\%$ NaCl solution for 36 hours increased to 47.8 mg, 29.5 mg and 5.4mg per 100g of the sample, respectively and increased slowly during the storage. The peroxide value and acid value of the lipid extracted from the product increased from 15.9 meq/kg to 114.0 meq/kg, and 12.6 to 30.5 during the storage. In the fatty acid composition, $C_{22:6}\;and\;C_{20:5}$ acids were decreased during the storage period.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.1
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• pp.11-23
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• 1998

The purpose of this study was to survey chemical distribution of inorganic elements and ions in the submicron particles, to characterize qualitatively emitting sources by factor analysis, and finally to reveal existing patterns in terms of chemical compounds by a stepwise multiple regression analysis. Total of 141 samples were collected by a cascade impactor from 1989 to1996. Fifteen chemical species (Al, Ba, Cd, K, Pb, Cu, Fe, Ni, $Cl^-, NO_3^-, SO_4^{2-}, K^+, Mg^{2+}, Ca^{2+}, and Na^+$) were characterized by AAS and IC. The study showed that average seasonal levels of submicron particulate matters $(d_p<0.43 \mum)$ were 18.7 $\mug/m^3$ in spring, 15.5 $\mug/m^3$ in summer, 15.7 $\mug/m^3$ in fall, and 24.5 $\mug/m^3$ in winter, respectively. All of the anion concentrations in the particle were highest in the winter season. By applying a factor analysis, 5 source patterns were qualitatively obtained, such as sulfate related source, nitrate related source, oil burning source, calcium related source, and coal combustion source. Finally, when applying a stepwise multiple regression analysis, the results clearly showed that $Na^+ and Ca^{2+}, K^+ and Ca^{2+}, NO_3^-$ and relative humidity, $Cl^-$ and ambient temperature, $Ca^{2+} and Cl^-, Mg^{2+} and SO_4^{2-}, Na^+ and NO_3^-, and Ca^{2+} and NO_3^-$, respectively, are negatively contributed to each other. As a result of those statistical analysis, we could suggest that some chemical compounds in the submicron particles such as$NaNO_3, MgSO_4, Ca(NO_3)_2, and CaCl_2$ may not exist on the filter as final composing products; however, other compounds may possibly exist in the form of $Mg(NO_3)_2, CaSO_4, Na_2SO_4, K_2SO_4, MgCl_2, NaCl, and KCl$. Thus, it must be necessary to identify differences between the results of above statistical analysis and of the real world by laboratory experiments.

• Journal of Plant Biology
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• v.33 no.4
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• pp.277-283
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• 1990

Inactivation and reactivation of photosynthetic oxygen evolving complex were studied with isolated spinach (Spinacia oleraceda. L.) photosystem II particles by the activity of oxygen evolution and chlorophyll fluorescence. When the particles were treated with Tris and urea, the oxygen evolution was inactivated and three polypeptides having molecular weights of 33 kDa, 24 kDa and 18 kDa were simultaneously released. But in NaCl-treated particles, two polypeptides of 24 kDa and 18 kDa were removed from PS II particles. The oxygen evolution activities of Tris and urea-treated particles were not restored by adding cation ions (Mg2+, Mn2+ and Ca2+), but the NaCl-treated particles were restored by exogenously added Ca2+. The removal of these extrinsic polypeptides, especially 33 kDa, markedly showed the decrease of the variable fluorescence (Fv). These results are likely to be due to dissipate thermal energy by antenna of photosystem II complexes.