• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3251-3259
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• 2014

This paper presents experimental and analytical research results to predict nonlinear flexural behavior of corroded reinforced concrete beams. For this purpose, a series of test and an analytical simulation using the Maaddawy's model were carried. Test specimens of total 12 RC beams were placed in accelerated corrosion status using salt water spray test chamber for 5 months and 10 months, after they were preloaded up to 30% and 60% of the maximum load corresponding to nominal flexural strength. The test results showed that flexural strength and ductility decreased to 5.4% and 43% at the most respectively due to breakdown of bond at the steel-concrete interface. Comparative study between the analytical predictions and the experimental results showed that the Maaddawy's model can be applied to predict a real corroded RC flexural members.

• Current Photovoltaic Research
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• v.11 no.1
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• pp.8-12
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• 2023

In this work, we investigated the thickness of Ag precursor layer to improve the performance of flexible CIGSe solar cells grown on stainless steel (STS) substrates through three-stage co-evaporation with Ga grading followed by alkali treatments. The small amount of incorporated Ag in CIGSe films showed enhancement in the grain size and device efficiency. With an optimal 6 nm-thick Ag layer, the best cell on the STS substrate yielded more than 16%, which is comparable to the soda-lime glass (SLG) substrate. Thus, the addition of controlled Ag combined with alkali post-deposition treatment (PDT) led to increased open-circuit voltage (VOC), accompanied by the increased built-in potential as confirmed by capacitance-voltage (C-V) measurements. It is related to a reduction of charge recombination at the depletion region. The results suggest that Ag alloying and alkali PDT are essential for producing highly efficient flexible CIGSe solar cells.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.2
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• pp.94-102
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• 2024

The exact mechanism of sialolith formation has yet to be determined. Recurrence of sialolithiasis is rare, affecting only 1%-10% of patients. The current study presents a case of recurrent stones that occurred twice on the right submandibular gland 6 months postoperative and 7 months after reoperation in a 48-year-old female patient. The stones were analyzed using histology, scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy (TEM). The first stone showed a three-layered structure with a poorly mineralized peripheral multilayered zone, highly mineralized middle layer, and the central nidus. The stones were composed of Ca, C, O, Cu, F, N, P, Si, Zn, and Zr. In TEM, compact bi-layered bacterial cell membrane was found on the peripheral layer and the central nidus of the stone as well as exosomes in the central nidus. The results demonstrated the essential components of sialolith formation, including bacteria, inflammatory exosomes, and exfoliated salivary epithelial cells that cooperatively underwent the pathogenetic progresses of central nidus formation, induction of compact zone calcification of the middle layer, and repeated subsequent deposition in the peripheral multilayer zone. The rapid recurrence could have resulted from residual pieces of a sialolith acting as the nidus of bacterial infection.

• Korean Journal of Medicinal Crop Science
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• v.28 no.1
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• pp.1-8
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• 2020

Background: This study was conducted to investigate the effects of NaCl concentration on the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of Crepidiastrum sonchifolium. Methods and Results: As treatments, we subjected C. sonchifolium plants to four different concentrations of NaCl (0, 50, 100 and 200 mM). We found that the photosynthetic parameters maximum photosynthesis rate (P_{N max}), net apparent quantum yield (Φ), maximum carboxylation rate (V_cmax), and maximum electron transport rate (J_max) were significantly reduced at an NaCl concentration greater than 100 mM. In contrast, there was an increase in water-use efficiency with increasing NaCl concentration, although in terms of growth performances, leaf dry weight, root dry weight, stem length, and total dry weight all decreased with increasing NaCl concentration. Furthermore, leakage of electrolytes, as a consequence of cell membrane damage, clearly increased in response to an increase in NaCl concentration. Analysis of the polyphasic elevation of chlorophyll a fluorescence transients (OKJIP) revealed marked decrease in flux ratios (Φ_PO, Ψ_O and Φ_EO) and the PI_abs, performance index in response to treatment with 200 mM NaCl, thereby reflectings the relatively reduced state of photosystem II. This increase in fluorescence could be due to a reduction in electron transport beyond Q^-_A. We thus found that the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of C. sonchifolium significantly increased in response to treatment with 200 mM NaCl. Conclusions: Collectively, the findings of this study indicate that C. sonchifolium shows relatively low sensitivity to NaCl stress, although photosynthetic activity was markedly reduced in plants exposed to 200 mM NaCl.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.313-324
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• 2020

This study investigated the environmental location effects that Larix kaempferi and mixed forests had on the early growth of wild-simulated ginseng (Panax ginseng C. A. Meyer) seedlings. Experimental plots were created in Larix kaempferi and mixed forests, and confirmed the location environments and growth characteristics of wild-simulated ginseng seedling. Our results showed that the soil properties, such as soil organic matter, total nitrogen, and cation exchangeable capacity were significantly higher in the mixed forest soil compared to the Larix kaempferi forest soil. Likewise, the growth characteristics of wild-simulated ginseng seedlings were significantly higher in mixed forestsd compare to the Larix kaempferi forest. Correlation analysis between tree species ratio, soil properties, and growth characteristics in the experimental plots determined that the soil properties and growth characteristics had significant positive correlation with the broad-leaved forest percentage. Growth characteristics of the wild-simulated ginseng seedlings were shown to have a significant positive correlation with organic matter, total nitrogen, and cation exchange capacities. This study has clearly demonstrated that the tree species ratio, and soil properties in Larix kaempferi and mixed forests were significantly correlated with the early growth of wild simulated ginseng seedlings. These results could help to improve the selection of suitable cultivation sites for wild-simulated ginseng.

• Journal of The Korean Society of Clinical Toxicology
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• v.4 no.1
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• pp.7-16
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• 2006

Purpose: As basic information of antioxidant treatments for the patient with paraquat intoxication, in human peripheral lymphocytes, the cytotoxicity of paraquat was measured, and to evaluate the antioxidant effect of vitamin C and deferoxamine against this cytotoxicity, malondialdehyde (MDA), superoxide dismutase (SOD) activity and total antioxidant status (TAS) were measured. Methods: From 10 healthy adults, after obtaining a consent, 20ml peripheral blood was collected. Experimental groups were divided to (1) control group, the group treated with an identical amount of saline, (2) P group: the group treated with paraquat only, (3) PV group: the group treated with paraquat followed by vitamin C 30 minutes later, (4) PD group: the group treated with paraquat followed by deferoxamine 30 minutes later, (5) PVD group: the group treated with paraquat followed by vitamin C 30 minutes later and subsequently deferoxamine one hour later, and (6) PDV group: the group treated with paraquat followed by deferoxamine 30 minutes later and subsequently vitamin C 1 hour later, and thus to total 6 groups. In each group, 10 samples of peripheral blood was assigned and $100{\mu}M\;paraquat,\;100{\mu}M$ vitamin C, and $100{\mu}M$ deferoxamine were used as reagent. Lymphocytes were isolated, cultured, and cytotoxicity was measured by the Microculture Tetrazolium method (MTT assay), MDA and SOD activity, and TAS concentration were measured. Results: In regard to the cytotoxicity measured in each group, their cytotoxicity was decreased in the group treated with antioxidants, in comparison with the group treated with paraquat only. In the cases that the order of the treatment of these two antioxidants was altered, viability in the PDV group $(1.077{\pm}0.121)$ was increased more that the PVD group $(0.888{\pm}0.152)$ statistically significantly (p=0.018). Concerning the amount of MDA, in comparison with the P group $(6.78{\pm}0.93{\mu}mol/L)$, after the treatment of each antioxidant, the concentration of MDA was decreased statistically significantly (p<0.05). In the group treated with two antioxidants together, in comparison with the group treated only with one antioxidant, the amount of MDA was increased statistically significantly $(PV:\;3.96{\pm}0.98{\mu}mol/L,\;PD:\;4.92{\pm}1.50{\mu}mol/L,\;PVD:\;3.22{\pm}0.83{\mu}mol/L,\;and\;PDV:\;3.42{\pm}0.95{\mu}mol/L,\;p=0.007)$. The concentration of SOD measured in the blood in each group after the administration of paraquat, in comparison with the control group, a pattern of the elevation of SOD activity and subsequent decrease was detected, however, it was not statistically significant. In the comparison of the groups treated with antioxidants, in comparison with the P group $(1419.9{\pm}265.9{\mu}mol/L)$, SOD activity was decreased statistically significantly in only the PDV group $(1176.4{\pm}238.9{\mu}mol/L)$ (p=0.017). In regard to TAS measured in each group, in comparison with the P group $(0.87{\pm}0.05{\mu}mol/L)$, in all groups treated with the antioxidants, the PV group was $1.00{\pm}0.03{\mu}mol/L$ (p=0.005), the PD group was $9.01{\pm}0.24{\mu}mol/L$ was $4.64{\pm}3.98{\mu}mol/L$ (P=0.005), and the PDV group was $9.41{\pm}0.27{\mu}mol/La$ (p=0.005), and thus total antioxidant activity was increased statistically significantly In a multiple comparison test, the PDV group showed the highest total antioxidant activity (p<0.0001). Conclusion: The result of the assessment of the antioxidant effect of vitamin C and deferoxamine on paraquat-induced cytotoxicity showed that in regard to cytotoxicity, SOD activity and TAS measurement, the best result was observed in the PDV group. Therefore, it was found that vitamin C and deferoxamine were effective antioxidants for the paraquat-induced cytotoxicity, and it suggests that the administration of deferoxamine followed by vitamin C may improve their antioxidant effect more.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.2
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• pp.110-123
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• 2021

We investigated geochemical constituents of pore-water and sediment, rates of organic carbon (C_org) oxidation and sulfate reduction (SR), and benthic nutrient flux (BNF) to elucidate characteristic of C_org oxidation and its control in the coastal area near Lake Shihwa. The study sites were selected in the vicinity of Soraepogu (E0), Songdo tidalflat (E1) and Oido dock (E3) and in front of floodgate Shihwa tidal plant (E5). The C_org contents in the sediments and concentrations of ammonium and phosphate in pore water exhibited the highest value at EO, and gradually decreased toward the outer sea (E1, E3, E5). Rates of anaerobic C_org oxidation (260.6 mmol C m^-2 d^-1) and SR (91.4 mmol S m^-2 d^-1) at E0 were 4-9 and 6-54 times higher than at the site of outer sea (E1, E3, E5). Rates of SR at E3 and E5 accounted for 11-23% of anaerobic C_org oxidation, whereas it comprised 47-70% of anaerobic C_org oxidation at E0 and E1. Rates of C_org oxidation and SR showed a highly positive correlation with the concentration of dissolved organic carbon (r² = 0.795 and 0.777, respectively). The BNF at E0, E1, and E3 accounted for 120-510% and 26-178%, respectively, of the N and P required for primary production in the water column. Overall results suggest that the C_org oxidation in the sediment controlled by concentration of dissolved organic carbon in the pore water and the excessive C_org oxidation stimulates the benthic nutrient flux, which may cause a phytoplankton bloom in the water column.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.167-173
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• 2007

To study the transcriptional mechanisms by which expression of the murine glial cell-derived neurotrophic factor inducible transcription factor (mGIF) gene is regulated, a murine genomic clone was iso-lated using a mGIF cDNA as probe. A 13-kb genomic fragment, which comprises 4-kb upstream of the transcription initiation site was sequenced. The promoter region lacks a TATA box and CAAT box, is rich in G+C content, and has multiple putative binding sites for the transcription factor Spl. The mGIF gene also has consensus sequences for AP2 binding sites. The transcriptional activity of five deletion mutants of a 2.1-kb fragment was analyzed by modulating transcription of the heterologous luciferase gene in the promoterless plasmid pGL2-Basic. All mutants showed significant transcriptional activity in the murine neuroblastoma cell line NB41A3. Transient expression assays suggested the presence of a positive regulator between -213 and -129 while a negative regulator was found in the region between -806 and -214. Relatively strong transcriptional activity was observed in neuronal NB41A3, glial C6 cells and hepatic HepG2, but very weak activity in skeletal muscle C2C12 cells. These findings confirm the tissue-specific activity of the mGIF promoter and suggest that this gene shares structural and functional similarities with the dopamine receptor genes that it regulates.

• Childhood Kidney Diseases
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• v.9 no.2
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• pp.183-192
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• 2005

Purpose : The long term disease course and prognostic factors were evaluated in childhood Henoch-$Sch{\ddot{o}}nlein$ puruura nephritis(HSPN). Methods : A total of 75 children(44 boys and 31 girls) with HSPN were included in this study. The onset age was $8.0{\pm}3.1$ years(2.3-l5.3 years), and the follow-up period was $4.3{\pm}3.6$ years(1.0-17.1 years). Kidney biopsy was done in 24 children(32$\%$). Initial clinical and laboratory findings were evaluated. In addition, polymorphisms of the renin angiotensin system(RAS) genes(insertion/deletion in intron 16 of ACE gene, M235T in AGT gene, and A1166C in AGTR gene) were analysed. The initial and last clinical states were classified into 4 groups as follows A, normal; B, minor urinary abnormalities; C, active renal disease (nephrotic-range proteinuria and/or hypertension with serum creatinine $\leq$1.5 mg/dL); D, renal insufficiency. Results : At the onset, the clinical states of the patients were B in 26(35$\%$), C in 46(61$\%$), and D, in 3(4$\%$). The distribution of the RAS gene polymorphism of HSPN were not different from that of 100 healthy control subjects. At the last follow-up, the clinical states of the patients were A in 23(31$\%$), B in 38(50$\%$), C in 9(12$\%$), and D in 5(7$\%$). A multiple logistic regression identified age at the onset and initial urine protein excretion as significant prognostic factors. Analysis of genotypes of the 3 RAS genes as prognostic values revealed no statistical significance. Conclusion : Older age at onset and severe proteinuria were identified as poor prognostic factors of childhood HSPN. Implication of the RAS gene polymorphism In HSPN could not be validated in this small-scale retrospective study. (J Korean Soc Pediatr Nephrol 2005;9:183-192)

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.619-627
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• 2001

n order to increase the virus safety of a human intravenous immunoglobulin (IVIg) that was manufactured by a successive process of cold ethanol fractionation, polyethylene glycol precipitation, and pasteurization ($60^{\circ}C$ heat treatment for 10h), a low pH incubation process (pH 3.9 at $25{\circ}C$ for 14 days) was employed as the final step. The efficacy and mechanism of the fraction III cold ethanol fractionation, pasteurization, and low pH treatment steps in the removal and/or inactivation of blood-borne viruses were closely examined. A variety of experimental model viruses for human pathogenic viruses, including the Bovine herpes virus (BHV), Bovine viral diarrhoea virus (BVDV), Murine encephalomyocarditis virus (EMCV), and Porcine parvovirus (PPV), were selected for this study. The mechanism of reduction for the enveloped viruses (BHV and BVDV) during fraction III fractionation was both inactivation and partitioning, however, it was partitioning in the case of the nonenveloped viruses (EMCV and PPV). The log reduction factors achieved during fraction III fractionation were ${\geqq}$6.7 for BHV, ${\geqq}4.7$ for BVDV, 4.5 for EMCV, and 4.4 for PPV. Pasteurization was found to be a robust and effective step in inactivating all the viruses tested. The log reduction factors achieved during the pasteurization process were ${\geqq}7.5$ for BHV, ${\geqq}4.8$ for BVDV, 3.0 for EMCV, and 3.3 for PPV. A low pH incubation was very effective in inactivating the enveloped viruses as well as EMCV. The log reduction factors achieved during low pH incubation were ${\geqq}7.4$ for BHV, ${\geqq}3.9$ for BVDV, 5.2 for EMCV, and 2.0 for PPV. These results indicate that the low pH treatment successfully improved the viral safety of the final products.