• The Korean Journal of Pharmacology
• /
• v.11 no.2
• /
• pp.55-59
• /
• 1975

Safety study of the continuous releasing dichlorvos-resin insecticide $(Mopari^{\circledR})$ was conducted in human volunteers and domestic fowls. For the purpose, the potential hazards in using the insecticide were observed in terms of the inhibition of plasma cholinesterase activity and the changes in the liver function (GOT, GPT, Alkaline phosphatase, Bilirubin, Thymol turbidity), the blood picture (RBC, WBC with differential count, Hemoglobin, Hematocrit and ESR) and the urine picture (sugar, albumin, pH and microscopic findings) in 40 healthy adult volunteers and 60 leghorn domestic fowls. In case of the human study the observation was continued for 2 months during the application of the insectiside ($1{\sim}3$ solid formulations/$30m^3$) in the living rooms of ordinary Korean dwelling houses or in the office. In the animal test, however, 1 to 5 solid formulations of the insecticide were applied in the fowl cage of $9.2m^3$ for 5 weeks. Any significant inhibition of the plasma cholinesterase activity was not observed in both the human volunteer and the fowl throughout the experimental period. And the liver function as well as the blood and urine pictures were also not changed after exposure to the vaporizing insecticide. It is considered from the result that the amount of dichlorvos released into the air by the continuous vaporizing dichlorvos-resin insecticide presents no significant hazardous effect on humans or animals in the present experimental condition.

• Asian Journal of Atmospheric Environment
• /
• v.7 no.1
• /
• pp.1-7
• /
• 2013

To establish the method for investigating the behavior of aerosol particles deposited on the leaf surface against fog water under natural conditions, scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analysis and wash water analysis by ion chromatography after the washing treatment were performed using leaves of white birch collected from low part of the tree crown and the top of the tree in Sapporo City, Hokkaido, northern Japan. Each of collected leaves was divided into two parts according to the treatment performed: leaf surface (adaxial side) was 1) untreated, and 2) washed with deionized water with a pipette. In untreated samples, many particles of various shapes, including soil particles and organic debris, were deposited on the surface. Particles containing S were found on the surface of samples collected from only low part of the tree crown. After the washing treatment, SEM-EDX analysis revealed that soil particles and particles containing S had been washed off with water, although some particles such as soil particles and organic debris still remained on the leaf surface. The major anion such as $SO{_4}^{2-}$ was detected in wash water of all samples, although the peak of S in X-ray spectra was not detected from samples collected at top of the tree. The combination of SEM-EDX analysis with wash water analysis indicated that $SO{_4}^{2-}$ was deposited on the leaf surface in dissolved state and/or in state of submicron particles. These results suggested that fog water could remove soil particles and particles containing S and $SO{_4}^{2-}$ from the leaf surfaces, but not all particles. There was no difference in sampling position in the tree crown. Our study suggested that combination with SEM-EDX analysis and wash water analysis would be effective for investigation of the behavior of particles on the leaf surface against fog water.

• Environmental Engineering Research
• /
• v.11 no.3
• /
• pp.127-133
• /
• 2006

Aerobic floc-like sludge was formed in a batch reactor and the effect of cations on the formation of aerobic floc-like sludge was studied. In order to enhance the formation (rate) of aerobic floc-like sludge, cations such as $K^+$, $Na^+$, $Ca^{2+}$, and $Mg^{2+}$ were added to the seed sludge. It was found that $Ca^{2+}$ had positive effect on the formation of floc-like sludge, as measured by sludge volume index (SVI) for settle ability. The formation of floc-like sludge was confirmed by the microscopic observation after DAPI staining. The scattered forms of sludge samples at the initial stage became aggregated to form floes after $Ca^{2+}$ addition. To ensure the functions of sludge floes in a treatment plant, the gradient of ionic species around the surfaces of floc-like sludge was monitored by ion selective microelectrodes for ${NH_4}^+,\;{NO_3}^-$, and pH. The effective concentration of $Ca^{2+}$ ion to form floc-like sludge was determined to be 750 mg/L (0.15 mg $Ca^{2+}/mg$ MLSS). Under the effective $Ca^{2+}$ condition, the SVI value was the lowest and large distribution of nitrifying bacteria at the outer surface was observed in the aerobic floc-like sludge. From the results, it was found that the calcium ion functioned as an agent for the formation of aerobic floc-like sludge, resulting in the enhanced nitrification.

• Environmental Analysis Health and Toxicology
• /
• v.21 no.1 s.52
• /
• pp.71-79
• /
• 2006

Epidemiologic studies have showed a close correlation between arsenic exposure and heart disease such as, cardiovascular problem, ischemic heart disease, infarction, atherosclerosis and hypertension in human. It may increase the mortality of high risk group with heart disease. Regarding the mechanism studies of heart failure, blood vessel, vascular smooth muscle cells and endothelial cells have long been focused as the primary targets in arsenic exposure but there are only a few studies on the cardiomyocytes. In this study, the generation of oxidative stress by low dose of arsenic trioxide was investigated in rat cardiomyocytes. By direct measurement of reactive oxygen species and fluorescent microscopic observation using fluorescent dye 2',7'-dichlorofluorescin diacetate, reactive oxygen species were found to be generated without cell death, where cells are treated with 0.1 ppm arsenic for 24 hours. With the induction of reactive oxygen species, GSH level was decreased by the same treatment. However, DNA damage did not seem to be serious by DAPI staining, while high dose of arsenic (2 ppm for 24 hrs) caused fragmentation of DNA. To identify the molecular biomarkers of low-dose arsenic exposure, gene expression was also investigated with whole genome microarray. As results, 9,022 genes were up-regulated including heme oxygenase-l and glutathione S-transrerase, which are well-known biomarkers of oxidative stress. 9,404 genes were down-regulated including endothelial type gp 91-phox gene by the treatment of 0.1 ppm arsenic for 24 hours. This means that biological responses of cardiomyocytes may be altered by ROS induced by low level arsenic without cell death, and this alteration may be detected clearly by molecular biomarkers such as heme oxygenase-1.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.2
• /
• pp.139-143
• /
• 1999

The antimicrobial action of bacteriocin produced by lactobacillus sp. GM7311 against three Gram negative bacteria, Proteus mirabilis, Vibrio parahaemolyticus, and Escherichia coli, was investigated, When the bacteriocin was added to the culture at different stages, viable cells of all of the indicator strains tested were decreased, even though the most inhibited indicator cell growth stages were different. Transmission electron microscopic observation of indicator strains treated with bacteriocin revealed cell Iysis, indicating the cell membrane appears to be the primary site of action. The amino acids concentration of indicator strains treated with bacteriocin were diminished and fatty acids compositions were changed as compared with controls.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.4
• /
• pp.698-704
• /
• 1998

This study was carried out to investigate the effects of diet of Korean safflower(Carthamus tinctorious L.) seed powder on bone tissue during the recovery of rib-fracture in rats. Male Sprague-Dawley rats of 10 weeks old, weighing 370$\pm$5g, were divided into two groups including the control group(C group, AIN-76 semipurified diet) and safflower seed group(S group, AIN-76 semipurified diet+10% safflower seed powder) and were fed experimental diets for 12 days after adaptation period. After this period, the 9th right rib was fractured surgically and sham-operation was also performed. Rats were fed with experimental diets for up to 30 more days after rib-fracture. The degree of bone repair was evaluated during the recovery period at the 8th, 11th, 16th, 21st, 30th days after the surgical operation by microscopic observation of the fractured rib tissue. In callus formation, the portion of hyaline cartilage was noticably higher in S group than C group. The intracatilagenous ossification was observed at the 8th day in S group, but at 11th day in C group. The intramembranous ossification in callus was widely found over the 8th day to the 11th day in S group, but it was shown over the 11th day to the 16th day in C group. Bone resorption was also occured more rapidly in S group as indicated by large numbers of osteoclasts observed. At the 30th day, most of trabecular bones were disappeared in S group, whereas still shwon in C group over wide ranges of fractured ribs. These results imply that the supplementation of Korean safflower seed powder influences in the recovery of bone fracture by accelerating the process of bone repair.

• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.891-905
• /
• 2005

The present study was performed to evaluate the effect of tetracycline-HCL on the change of implant surface microstructure according to application time. Implant with pure titanium machined surface. HA-coated surface and TiUniteTM surface were utilized. Implant surface was rubbed with 50mg/ml tetracycline-HCL solution for $\frac{1}{2}min.$, 1min., $1\frac{1}{2}min.$, 2min., and $2\frac{1}{2}min.$ respectively in the test group. Then, specimens were processed for scanning electron microscopic observation. The results of this study were as follows. 1. Both test and control group showed a few shallow grooves and ridges in pure titanium machined surface implants. There were not significant differences between two groups. 2. In HA-coated surfaces, round particles were deposited irregularly. The roughness of surfaces conditioned with tetracycline-HCL was lessened and the cracks were increased relative to the application time. 3. The anodic oxidized surfaces showed the craterous structures. The surface conditioning with tetracycline-HCl didn't influence on its micro-morphology. In conclusion, the detoxification with 50mg/ml tetracycline-HCL must be applied respectively with different time according to various implant surfaces.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.13 no.3
• /
• pp.252-264
• /
• 1991

The purpose of this study was to compare the response of adjacent tissue and new bone formation after implantation by different methods of subperiosteal using using Proplast I and II in rabbit mandible. Microstructure of Proplast I and II was observed by scanning electron microscope. And the implantation procedure was carried out by dividing into tow groups, A and B. a group consisted of subperiosteal graft on the cortex, and the other B group was made up onlay graft following artificial decortication in the madibular body of rabbit. The experimental animals were sacrificed on the 1st, 2nd, 4th and 8th week after grafting for macroscopic and histopathologic examination. The samples extracted at the 6th postgrafting week were also used for biometric test. The result ere as follows : 1. By scanning electron microscopic observation, pore size was $50{\sim}180{\mu}m$ in the Proplast I and $100{\sim}220{\mu}m$ in Proplast II. 2. Macroscopically, infection of the graft site, deformation and displacement of the implanted materials were not observed in all experimental groups. 3. In the tissue response, infiltration of inflammatory cells and multinucleated giant cells were observed from the 2nd to the 8th week in Proplast I. Inflammatory cells decreased in number from the 2nd week in Proplast II suggesting that Proplast II is better than Proplast I. 4. Bone formation was not observed until the 8th week in the group A, but new bone formation from the surrounding graft bed and the periostium was appeared from the 4th week in the group B. 5. The maximum mean values of shear stress mere serially $65.5gf/mm^2$ in Proplast II of group B, $32.9gf/mm^2$ in Proplast I of group B, $17.0gf/mm^2$ in Proplast II of group A, and $15.7gf/mm^2$ in Proplast I. of group A.

• Korean journal of applied entomology
• /
• v.28 no.3
• /
• pp.105-112
• /
• 1989

The nuclear polyhedrosis viruses of Bombyx mori (BmNPV) and Hyphantria cunea (HcNPV) were characterized by electron microscopic observation, SDS-PAGE of polyhedral and virion proteins, and restriction endonuclease analysis of viral DNAs. Polyhedra of BmNPV were octadecahedral in shape with the diameter of $3 \mu\textrm{m}$, whereas those of HcNPV showed irregular appearances having the diameter of $1.5~2\mu\textrm{m}$. Under alkaline protease inactivated condition, polyhedral proteins of two NPVs were resolved into a major polypeptide, 30~31 KD, and several minor polypeptides by SDS-PAGE. Examination of virion proteins by silver staining after SDS-PAGE showed that BmNPV was composed of 47 polypeptides with M.W. range of 9.6~112 KD and HcNPV was composed of 48 polypeptides with M.W. range of 9.4~111 KD. The approximate genome size of two NPVs were determined by restriction endonuclease analysis: BmNPV and HcNPV were 114.6 Kb, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.5 no.1
• /
• pp.50-59
• /
• 1995

Abstract 6 H - SiC single crystal was grown by sublimation growth system which was self - designed and manufactured. In order that the SiC source might be decomposited and sublimed and deposited on the 6H - seed substrate grown by Acheson method, the temperature gradient, the growth parameters of growth temperature and pressure were operately adjusted. So we could get the optimum temperature gradient inside of the crucible. The graphite crucible with SiC powder and thermal shield componants were purified at the elevated temperature by means of Ar purging process and the source baking, then it distributed to reduce the amount of the impurities come from those parts. It was recognized that the optimum growth temperature of the crucible was$2300~2400^{\circ}C$ at the Ar atmospheric pressure of 200~400 torr, and at that moment the growth rate was 500~1000 $\mu\textrm{m}$. And then, the as- grown crystal was cut with the wafer form, the evaluation about the crystal was carried out by XRD, the optical microscopic observation and FT IR spectrum measurement.