• Journal of Korea Foundry Society
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• v.41 no.5
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• pp.419-433
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• 2021

Al-Si-Cu alloys benefit from the addition of copper for better hardness and strength through precipitation hardening, which results in remarkably strong alloys. However, the addition of copper expands the solidification range of Al-Si-Cu alloys, and due to this, these alloys become more prone to hot tearing, which is one of the most common and serious fracture phenomena encountered during solidification. The conventional evaluation method of the hot tearing properties of an alloy is a relative and qualitative analysis approach that does not provide quantitative data about this phenomenon. In the present study, the mold itself part of a device developed in Instone et al. was partially modified to obtain more reliable quantitative data pertaining to the hot tearing properties of an Al-Si-Cu casting alloy. To assess the influence of Cu element, four levels of Cu contents were tested (0.5, 1.0, 3.0, and 5.0 wt.%) in the Al-Si-Cu system alloy and the hot tearing properties were evaluated in each case. As the Cu content was increased, the hot tearing strength decreased to 2.26, 1.53, 1.18, and 1.04 MPa, respectively. At the moment hot tearing occurred, the corresponding solid fraction and solidification rate decreased at the same temperature due to the increase in the solid-liquid coexistence range as the Cu content increased. The morphology of the fracture surfaces was changed from dendrites to dendrites covered with residual liquid, and CuAl₂ phases were observed in the vicinity of hot tearing.

• 한국노년학
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• v.30 no.1
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• pp.179-194
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• 2010

The purpose of this study examines the elderly hemodialysis patients' Health-related quality in life(HRQL) and investigates the relationship between HRQL and transition of health condition. The subject were 443 elderly hemodialysis patients(over 65 years old) in Seoul and Gyeonggi province. The Health-related quality of life scale was used in this research, in which were analysed a wide range of statistical descriptive analysis, Pearson's correlation, reliability analysis, multiple regression and the Scheffe test. The results were as follows. The HRQL were statiscally significant difference by Gender, Educational level, Live with spouse, Best supporter, and Number of Disease. Also the factor related to transition of health condition was Number of Disease. The transition of health condition accounted for 13.9% of variance in HRQL and Number of Disease accounted for an additional 7.4% of HRQL. The factors, which influenced finally on the HRQL in the elderly hemodialysis patients, were transition of health condition and number of disease. In conclusion adequate hemodialysis treatment and social services should be provided in accordance with the factors affecting HRQL in order to improve the HRQL for elderly hemodialysis patients.

• Safety and Health at Work
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• v.10 no.3
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• pp.377-383
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• 2019

Objectives: Exposure to fine particles in urban air has been associated with a number of negative health effects. High levels of fine particles have been detected at underground stations in big cities. We investigated the exposure conditions in four occupational groups in the Stockholm underground train system to identify high-exposed groups and study variations in exposure. Methods: $PM_1$ and $PM_{2.5}$ were measured during three full work shifts on 44 underground workers. Fluctuations in exposure were monitored by a real-time particle monitoring instrument, pDR, DataRAM. Qualitative analysis of particle content was performed using inductively coupled plasma mass spectrometry. Nitrogen dioxide was measured using passive monitors. Results: For all underground workers, the geometric mean (GM) of $PM_1$ was $18{\mu}g/m^3$ and of $PM_{2.5}$ was $37{\mu}g/m^3$. The particle exposure was highest for cleaners/platform workers, and the GM of $PM_1$ was $31.6{\mu}g/m^3$ [geometric standard deviation (GSD), 1.6] and of $PM_{2.5}$ was $76.5{\mu}g/m^3$ (GSD, 1.3); the particle exposure was lowest for ticket sellers, and the GM of $PM_1$ was $4.9{\mu}g/m^3$ (GSD, 2.1) and of $PM_{2.5}$ was $9.3{\mu}g/m^3$ (GSD, 1.5). The $PM_1$ and $PM_{2.5}$ levels were five times higher in the underground system than at the street level, and the particles in the underground had high iron content. The train driver's nitrogen dioxide exposure level was $64.1{\mu}g/m^3$ (GSD, 1.5). Conclusions: Cleaners and other platform workers were statistically significantly more exposed to particles than train drivers or ticket sellers. Particle concentrations ($PM_{2.5}$) in the Stockholm underground system were within the same range as in the New York underground system but were much lower than in several older underground systems around the world.

• Maritime Security
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• v.1 no.1
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• pp.311-343
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• 2020

Because of the global warming, the Arctic Ocean is expected to be ice-free by the year 2035. When the Arctic Ocean will be opened, a number of national interests will become more salient as experiencing a shortened sailing distance and decreasing navigation expense, possibility of natural resources transport by sea from Arctic Circle, and indirect-profit making by building a herb port in Asia. To secure the national interests and support the free activities of people in this region, R.O.K government is trying to make advanced policies. In order to carry out the naval tasks in the Arctic Ocean, using the operational characteristics(mobility, flexibility, sustainability, presence of capabilities, projection) is necessary. To this end, ROK Navy should analyze the operational environment (O.E.) by its capability(weakness and strength), opportunity, and threat. R.O.K. Navy should make an effort over the following issues to implement the tasks in the Arctic Ocean: first, Navy needs to map out her own plan (Roadmap) under the direction of government policies and makes crews participate in the education·training programs in home and abroad for future polar experts. Third, to develop the forces and materials for the tasks in cold, far operations area, Navy should use domestic well-experienced shipbuilding skills and techniques of the fourth industrial revolution. Next, improving the combined operations capabilities and military trust with other countries in the Arctic region to cover the large area with lack of forces' number and to resolve the ports of call issues. Lastly, preparation in advance to execute a variety of missions against military and non-traditional threats such as epidemics, HA/DR, SOLAS, in the future operation area is required.

• Archives of Craniofacial Surgery
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• v.25 no.1
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• pp.11-16
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• 2024

Background: The pathogenesis of orofacial cleft (OFC) is multifactorial, involving both genetic and non-genetic factors, the latter of which play a key role in the development of these anomalies. This paper addresses the incidence of OFC in Indonesia, with a focus on identifying and examining the distribution of contributory factors, including parental medical history, pregnancy history, and environmental influences. Methods: The study was conducted through the collection of primary data. An interdisciplinary research team from Indonesia administered a standardized questionnaire to parents who had children with OFC and who had provided informed consent. The case group comprised 133 children born with cleft lip and/or palate, and the control was 133 noncleft children born full-term. The risk factors associated with OFC anomalies were analyzed using the chi-square test and logistic regression. All statistical analyses were performed using SPSS version 25. A p-value of 0.05 or less was considered to indicate statistical significance. Results: The study comprised 138 children, of whom 82 were boys (59.4%) and 56 were girls (40.6%). Among them, 45 patients (32.6%) presented with both cleft lip and cleft palate, 25 individuals (18.1%) had a cleft palate only, and 28 patients (20.3%) had a cleft lip only. OFC was found to be significantly associated with a maternal family history of congenital birth defects (p<0.05), complications during the first trimester (p<0.05), consumption of local fish (p<0.05), caffeine intake (p<0.05), prolonged medication use (p<0.05), immunization history (p<0.05), passive smoking (p<0.05), and X-ray exposure during pregnancy (p<0.05). Conclusion: The findings indicate close relationships between the incidence of OFC and maternal medical history, prenatal factors, and environmental influences.

• International Journal of Stem Cells
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• v.16 no.4
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• pp.425-437
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• 2023

Obesity, which continues to increase worldwide, was shown to irreversibly impair the differentiation potential and angiogenic properties of adipose tissue mesenchymal stromal cells (ADSCs). Because these cells are intended for regenerative medicine, especially for the treatment of inflammatory conditions, and the effects of obesity on the immunomodulatory properties of ADSCs are not yet clear, here we investigated how ADSCs isolated from former obese subjects (Ex-Ob) would influence macrophage differentiation and polarization, since these cells are the main instructors of inflammatory responses. Analysis of the subcutaneous adipose tissue (SAT) of overweight (OW) and Ex-Ob subjects showed the maintenance of approximately twice as many macrophages in Ex-Ob SAT, contained within the CD68⁺/FXIII-A^- inflammatory pool. Despite it, in vitro, coculture experiments revealed that Ex-Ob ADSCs instructed monocyte differentiation into a M2-like profile, and under inflammatory conditions induced by LPS treatment, inhibited HLA-DR upregulation by resting M0 macrophages, originated a similar percentage of TNF-α⁺ cells, and inhibited IL-10 secretion, similar to OW-ADSCs and BMSCs, which were used for comparison, as these are the main alternative cell types available for therapeutic purposes. Our results showed that Ex-Ob ADSCs mirrored OW-ADSCs in macrophage education, favoring the M2 immunophenotype and a mixed (M1/M2) secretory response. These results have translational potential, since they provide evidence that ADSCs from both Ex-Ob and OW subjects can be used in regenerative medicine in eligible therapies. Further in vivo studies will be fundamental to validate these observations.

• Korean Journal of Poultry Science
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• v.39 no.4
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• pp.297-303
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• 2012

To investigate the effects of dietary substituent of corn distiller's dries grains with solubles (CDDGS) on the amino acid digestibility of broiler diet, twenty four Ross broilers (6-wk-old) were used in this study. Basal diet (CP 19%, ME 3,150 kcal/kg) was formulated on corn-soybean meal and two levels of CDDGS (6 and 12%) were supplemented to basal diet. CDDDS levels (0, 6 and 12%) and 4 different sites of chicken intestines (distal end of jejunum, the middle part of the ileum, the distal end of ileum and the distal end of the rectum) were evaluated factorial as $3{\times}4$ three arrangement. Statistical analysis did not show any significant interaction between dietary treatments and the sites of the intestines in amino acid digestibility (P>0.05). There was no significant difference among the sites of chicken intestines in the digestibility (P<0.05). The digestibility of lysine (essential amino acid) and glycine (non-essential amino acid) decreased at increasing supplementation of CDDGS (P<0.05). There was no significant difference on the digestibility of other amino acids studied. In conclusion, the result of this work showed that CDDGS can use as alternative resources in broiler diets.

• Archives of design research
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• v.17 no.4
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• pp.241-250
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• 2004

In this research, the copper alloy plates C2200, C5210, C7701, C8113 were selected to make datum and to identify further usage of metal craft experimentation. For its experimentation, the general welding and TIG welding methods were researched; for 2nd experimentation, the Reticulation and Electroforming skill's differences in color and temperature were researched. With these methods 3 different kinds of works are introduced for sample studies. For this research, Dr. Lee, Dong-Woo who works in Poongsan Metal Co, supported 4 kinds of copper alloy metals. Which are Commercial bronze (Cu-Zn), Deoxidiged Copper(Cu-Sn-P), Nickel Silver (Cu-Ni-Zn), and White Bronze (Cu-Ni); they were applied partly and wholly by the method of Laminatin, Reticulation, Fusing, and Electroforming skills. In case of C2200, the brass, the A. C. TIG welding method is better under 2mm slight plate; the D.C. TIG welding is better upper 2mm plate; and 250~300$^{\circ}C$ is recommended for remain heat treatment. In case of C5210, not having Hydrogen in high temperature return period, doesn't need Oxygen in high temperature and hardening in comparative high temperature neither, it is good for welding. It contains Sn 2-9% ad P 0.03-0.4% generally; and in accordance with the growth rate of Sn contain amount, the harden temperature boundary become broad. In case of cold moment after welding, they are recommended that higher speed TIG welding, smaller melting site and less than 200$^{\circ}C$ for pre-heating temperature. In case of C7701, the 10-20% Ni, 15-30% Zn are widely used.. If it is upper 30% Zn, it become (${\alpha}+{\beta}$) system and adhesive power rate become lower, and the productivity become lower in low temperature but the productivity become higher in high temperature. Nickel Silver's resistance of electricity is well; and the heatproof and incorrodibility is good, too. Lastly, in case of C8113, good at persistence in salty and grind; high in strength of high temperature. In case of white brass, contain 10-30% Nickel and hardened in high temperature and become single phrase. For these reason, the crystallization particles easily become large, if the resistance become higher small amount of Pb, P, S separation rate become higher.

• Tuberculosis and Respiratory Diseases
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• v.54 no.4
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• pp.367-377
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• 2003

Background : It is well known that only 10% of those infected with Mycobacterium tuberculosis actually develop clinical disease, indicating the existence of host genetic factors regulating disease expression. In this study, we investigated HLA-DRB1 and -DQB1 gene polymorphisms in Korean patients with pulmonary tuberculosis (PTB). Methods : HLA-DRB1 and -DQB1 gene polymorphisms were investigated in 67 PTB patients without previous treatment history, 38 drug-sensitive (DS) and 29 multidrug-resistant (MDR) cases, and 200 healthy controls. HLA-DRB1 typing was done using reverse SSO (sequence specific oligonucleotide) and PCR-SSCP (single strand conformational polymorphism) methods and DQB1 typing was done using PCR-RFLP (restriction fragment length polymorphism), PCR-SSCP and PCR-SSP (sequence specific primer) methods. Results : Among the PTB patients, MDR-TB cases showed frequencies of DRB1*0701 and *08032 increased by about two-fold compared to those of normal controls, and likewise for their associated DQB1 alleles, DQB1*0202 and *0601 (15.5% vs. 34.5%, p=0.01). The frequency of HLA-DQB1*0609 was significantly increased in PTB patients (4.0% vs. 14.9%, p=0.004), showing similar increases in both DS and MDR cases. There was also an association of HLA alleles with the clinical severity of the disease according to the extent of lung lesion. Significantly increased frequencies of DRB1*08032 (4.2% vs. 32.6%, p=0.007) and DQB1*0601 (12.5% vs. 34.9%, p=0.047) were observed in more advanced (moderately & far advanced/DS and far advanced/MDR), compared with less advanced (minimal/DS and moderately advanced/MDR) lung lesions. Although DRB1*0701, DQB1*0202 and DQB1*0609 showed significant increases in different subsets of the disease, these HLA alleles did not show consistent association with disease severity. Conclusion : HLA-DRB1*08032 and DQB1*0601 alleles were associated with genetic susceptibility to MDR-TB in Korean patients, and also with disease severity and progression of PTB.

• Tuberculosis and Respiratory Diseases
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• v.41 no.3
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• pp.215-221
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• 1994

Background: It is well known that oxygen free radicals(OFR) play a vital role in the various type of acute lung injury. Among various antioxidant defense mechanisms, the superoxide dismutases(SOD) are thought to be the first line of antioxidant defense by catalyzing the dismutation of two superoxide radicals to yield hydrogen peroxide and oxygen. Eukaryotic cells contain two types of intracellular SOD : cytosolic, dimeric copper/zinc- containing enzyme(CuZnSOD) and mitochondrial, tetrameric manganese-containing enzyme(MnSOD). The purpose of this study is to evaluate the time-dependent gene expression of MnSOD and CuZnSOD in the endotoxin-treated rats, and to compare with the manifestations of LPS-induced acute lung injury in rats. Methods: Total RNA from rat lung was isolated using single step phenol extraction 0, 1, 2, 4, 6, 12, 18, 24 hours after E. coli endotoxin injection(n=3, respectively). RNA was separated by formaldehyde-containing 1.2% agarose gels elctrophoresis, transblotted, baked, prehybridized, and hybridized with $^{32}P$-labeled cDNA probes for rat MnSOD and CuZnSOD, which were kindly donated by Dr. Ho(Duke University, Durham, NC, USA). The probes were labeled by nick translation. Blots were washed and autoradiography were quantitated using laser densitometry. Equivalent amounts of total RNA/gel were assessed by monitoring 28S and 18S rRNA. Results: Endotoxin caused a rise in steady-state MnSOD mRNA levels by 4h with peak mRNA accumulation by 6h. Continued MnSOD mRNA expression was observed at 12h. CuZnSOD mRNA expression was observed from 1h to 24h with peak levels by 18h. Conclusion: These results suggest that SOD palys an important defensive role in the endotoxin-induced acute lung injury in rats.