• Toxicological Research
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• v.4 no.1
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• pp.55-84
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• 1988

This study was carried out to investigate the teratological potential of azinphos-methyl in the rat fetuses and to establish the nature of the effects on organogenesis and intrauterine development. The Sprague-Dawley female rats (180-210g) without previous litter were used in this study. Azinphos-methyl dosages of 0.094mg/kg, 0.4mg/kg, 1.5mg/kg were selected based on the acute intragastric $LD_{50}$ of 15mg/kg in the rat. Azinphos-methyl in water (Treatment Group), non-treatment control (Negative Control), water control (Sham Control), were administered by oral route and aqueous solution of acetyl salicylic acid (Positive Control) was administered by gavage at rate of 10 ml/kg of body weight from day 6 through 15. The results obtained were summarized as follows. 1. Decreased body weight of dams was observed in animals treated with aspirin and azinphos-methyl 1.5 mg/kg from day 7 through 14. (P<0.01) 2. There was an apparent decrement in the absolute liver weight in the azinphos-methyl 1.5 mg/kg treated group (P<0.05). However, the absolute and relative kidney weight in aspirin group (P<0.05, P<0.01) and the absolute and relative ovary weight in aspirin, azinphos-methyl treatment groups (P<0.01, P<0.05) were increased. 3. Decreased protein contents of dam's liver was observed in the aspirin and high dose azinphos-methyl treated group of animals (P<0.01). 4. The number of male-female ratio per dam increased in azinphos-methyl 1.5 mg/kg group but there was an apparent decrement in the body weight of fetuses in aspirin and high dose azinphos-methyl group (P<0.01, P<0.05). Total immature and resorbed fetuses were increased in aspirin group and the number of dead fetuses were also increased in azinphos-methyl 1.5mg/kg treated group of animals. (P<0.01, P<0.05). 5. In soft tissue defects, diaphragmatic hernia in diaphragm, anophthalmia, enlarged olfactory bulb, hydrocephalus, absence of third and lateral ventricle in skull, hydronephrosis in kidney, atrophy of left ventricle wall, enlarged apex in heart were observed. Especially, defects of diaphragm, heart and eye ball showed peak incidences in the high dose azinphosmethyl and aspirin group. (P<0.01). 6. Variations in the ossification patterns of skull, sternebrae, tail, forelimbs and hindlimbs showed peak incidences in the aspirin and high dose azinphos-methyl group. (P<0.01). 7. In the developmental indices of offspring, the mortality of aspirin and azinphos-methyl 1.5mg/kg treated group was higher than that of negative control. And, there was an apparent decrement in the body weight of fetuses (P<0.01) and considerable differences were obtained in pivoting, development of fur, auditory function, vision, quadrupled muscle development and testes descent in aspirin and azinphos-methyl 1.5mg/kg group. (P<0.01).

• Microbiology and Biotechnology Letters
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• v.15 no.6
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• pp.388-395
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• 1987

In order to obtain a regulatory mutant strain with high cellulase activity, a newly isolated Penicillium verrculosum, strain F-3 was used as parental strain since it was proved to be an efficient cellulase producer. A number of experiments were conducted to determine the optimum conditions to in-duce mutagenesis and isolate the desirable mutant strains. Out of several restriction compounds tested, 1.5% oxgall was found to be most effective to restrict the colony size by suppressing overgrowth. Derepression of catabolites was employed as a criterion in selecting mutant strains with high cellulase productivity. Production of cellulase by Penicillium venculosum F-3 was suppressed when cultured on the media with more than 1% of glucose or glycerol. It was found that either irradiation with UV light for 19 mins or treatment with nitrosoguanidine at 200$\mu\textrm{g}$/m1 for 60 mins, induced mutagenesis at desired level, when the survival rate of the spore was 0.2% and 48%, respectively. Three mutant strains of F-3, UV-9, UV-10, and NTG-3 that had the highest cellulase productivity were finally selected, based on filter paper degradation rate, size of clearing zone on the screening plate and cellulase activity in the medium containing cellulose powder. When the mutant strains were compared with parental strain F-3, on the KC-M-W medium containing cellulose powder, the filter paper activities of UV-9, UV-10, and NTG-3 were increased by 34%, 55%, and 41%, respectively. However, the assimilation of cellobiose octaacetate by UV-9 or NTG-3 was markedly reduced. When the mutant UV-10 was grown on cellobiose octaacetate medium (CCA-4) in shaking flasks, the cellulase activities of the mutant increased by 20 to 50% compared to the parental strain. Excreation of soluble protein from the mutant also elevated up to 30%. The mutant also constitutively produced both CMCase and $\beta$-glucosidase, though at relatively low level, in the presence of glucose or cellobiose as carbon sources.

• Economic and Environmental Geology
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• v.53 no.4
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• pp.347-362
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• 2020

Iron (hydro)oxides in aqueous environments are primarily formed due to mining activities, and they are known to be typical colloidal particles disturbing surrounding environments. Among them, hematites are widespread in surface environments, and their behavior is controlled by diverse factors in aqueous environments. This study was conducted to elucidate the effect of environmental factors, such as ionic composition and strength, pH, and natural organic matter (NOM) on the behavior of colloidal hematite particles. In particular, two analytical methods, such as dynamic light scattering (DLS) and single-particle ICP-MS (spICP-MS), were compared to quantify and characterize the behavior of colloidal hematites. According to the variation of ionic composition and strength, the aggregation/dispersion characteristics of the hematite particles were affected as a result of the change in the thickness of the diffuse double layer as well as the total force of electrostatic repulsion and van der Walls attraction. Besides, the more dispersed the particles were, the farther away the aqueous pH was from their point of zero charge (PZC). The results indicate that the electrostatic and steric (structural) stabilization of the particles was enhanced by the functional groups of the natural organic matter, such as carboxyl and phenolic, as the NOM coated the surface of colloidal hematite particles in aqueous environments. Furthermore, such coating effects seemed to increase with decreasing molar mass of NOM. On the contrary, these stabilization (dispersion) effects of NOM were much more diminished by divalent cations such as Ca²⁺ than monovalent ones (Na⁺), and it could be attributed to the fact that the former acted as bridges much more strongly between the NOM-coated hematite particles than the latter because of the relatively larger ionic potential of the former. Consequently, it was quantitatively confirmed that the behavior of colloidal hematites in aqueous environments was significantly affected by diverse factors, such as ionic composition and strength, pH, and NOM. Among them, the NOM seemed to be the primary and dominant one controlling the behavior of hematite colloids. Meanwhile, the results of the comparative study on DLS and spICPMS suggest that the analyses combining both methods are likely to improve the effectiveness on the quantitative characterization of colloidal behavior in aqueous environments because they showed different strengths: the main advantage of the DLS method is the speed and ease of the operation, while the outstanding merit of the spICP-MS are to consider the shape of particles and the type of aggregation.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.113-118
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• 2017

BACKGROUND: The carbon (C) isotope ratio (${\delta}^{13}C$) of dissolved organic C (DOC) is an indicator of water pollution source. In this study, the potential use of two pre-treatments for the ${\delta}^{13}C$ analysis, alkaline persulfate oxidation coupled with carbonate precipitation (precipitation) and freeze drying (drying), were compared to suggest a more feasible pre-treatment method. METHODS AND RESULTS: Two reference materials with different ${\delta}^{13}C$ values were used for the experiments; chemical grade glucose ($-12.0{\pm}0.02$‰) and pig manure compost extract ($-23.3{\pm}0.04$‰). In the precipitation method, the measured ${\delta}^{13}C$ values were consistently lower than the theoretically calculated values as dissolved $CO_2$ could not be removed due to the alkaline property of the reagents and the dissolution of air $CO_2$ into the alkaline solution. The drying method also resulted in more negative ${\delta}^{13}C$ than the calculated ${\delta}^{13}C$; however, the difference was systematic ($3.9{\pm}0.3$‰) and there was a strong correlation (${\delta}^{13}C_{calculated}=0.87{\times}{\delta}^{13}C_{measured}-0.624$, $r^2=0.98$) between the calculated and measured ${\delta}^{13}C$. Calibration of ${\delta}^{13}C$ using the relationship between the calculated and the measured ${\delta}^{13}C$ values produced reliable and accurate ${\delta}^{13}C$ values. CONCLUSION: Our results suggest that the drying method is more accurate pre-treatment method to minimize the influence of air $CO_2$ compared to the precipitation method for the determination of ${\delta}^{13}C$ of DOC.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.3
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• pp.78-86
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• 2018

Purpose: We aimed to delineate clinical spectrum and short-term effects after enzyme replacement therapy (ERT) for 5 mucopolysaccharidosis type II (MPS II). Methods: Five patients were diagnosed with MPS II by clinical findings, enzyme activity, and genetic testing. Idursulfase was administered by intravenous infusion at a dose of 0.5 mg/kg every week. Observational chart analysis of patients, who underwent systematic investigations more than 12 months after initiation of ERT was done retrospectively. Results: Three patients were classified as having the attenuated type, and 2 patients were classified as having the severe type. The median age at the diagnosis was 9.6 years (range 3.4-26 years). Four different mutations in 5 Korean patients (4 families) with MPS II were identified, among which two were novel mutations (1 small insertion mutation: p.Thr409Hisfs*22, and 1 missense mutation: p.Gly134Glu). Two severe type sibling patients with the same mutation had different clinical manifestation. Urinary glycosaminoglycan excretion decreased within the twelve months of ERT (P=0.043). Liver and spleen volumes showed reductions that were maintained in all patients (P=0.043 and P=0.043, respectively). Improvements were also noted in left ventricular mass index (P=0.042), shoulder flexion (P=0.043), shoulder abduction (P=0.039), knee flexion (P=0.043), elbow flexion (P=0.042), and respiratory distress index (P=0.041). Conclusion: This study demonstrates that Korean patients with MPS II are clinically heterogeneous and indicates that idursulfase is relatively effective in several clinical parameters including heart size and respiratory distress index without infusion-related reactions in patients with MPS II.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.306-318
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• 2018

In order to evaluate the seismic capacity of massive vertical type breakwaters which have intensively been deployed along the coast of South Korea over the last two decades, we carry out the preliminary numerical simulation against the PoHang, GyeongJu, Hachinohe 1, Hachinohe 2, Ofunato, and artificial seismic waves based on the measured time series of ground acceleration. Numerical result shows that significant sliding can be resulted in once non-negligible portion of seismic energy is shifted toward the longer period during its propagation process toward the ground surface in a form of shear wave. It is well known that during these propagation process, shear waves due to the seismic activity would be amplified, and non-negligible portion of seismic energy be shifted toward the longer period. Among these, the shift of seismic energy toward the longer period is induced by the viscosity and internal friction intrinsic in the soil. On the other hand, the amplification of shear waves can be attributed to the fact that the shear modulus is getting smaller toward the ground surface following the descending effective stress toward the ground surface. And the weakened intensity of soil as the number of attacking shear waves are accumulated can also contribute these phenomenon (Das, 1993). In this rationale, we constitute the numerical model using the model by Hardin and Drnevich (1972) for the weakened shear modulus as shear waves go on, and shear wave equation, in the numerical integration of which $Newmark-{\beta}$ method and Modified Newton-Raphson method are evoked to take nonlinear stress-strain relationship into account. It is shown that the numerical model proposed in this study could duplicate the well known features of seismic shear waves such as that a great deal of probability mass is shifted toward the larger amplitude and longer period when shear waves propagate toward the ground surface.