• Fibers and Polymers
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• v.1 no.1
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• pp.32-36
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• 2000

An alternative strategy to .educe the percolation threshold of carbon black (CB) in polymer blends was investigated using random copolymer ternary blends of polystyrene (PS), poly(methyl methacrylate)(PMMA), and a styrene-methyl methacrylate random copolymer (SMMA). The target morphology was to selectively locate CB particles in the encapsulating layer of SMMA during melt mixing. The CB used in this study is BP-2000 from Cabot and has a strong selective affinity to PS. Even when the CB was premixed with SMMA, it moves to the PS phase during the melt mixing. However, we also observed the CB particles located at the interface between SMMA and PS phases. Through this study it is found that the interaction between polymers and CB particles is critical for selectively localizing CB particles in multi-component polymer blends. Although appropriate processing condition may retard the movement of CB particles to the polymer phase with affinity, it cannot prevent it completely and locate them to the SMMA phase, which is not thermodynamically favored. To locate CB particles in an encapsulating layer of ternary polymer blends, first of all, polymers forming it should have selective affinity to CB.

• Journal of the Korean housing association
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• v.23 no.5
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• pp.75-86
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• 2012

The primary purpose of this study is to prove the relationship between housing environment and mental health with depression and self-esteem in the republic of Korea. The raw data of 10,608 respondents, was gathered from the 4th wave of Korea Welfare Panel Study (KoWePS) in 2009. Some variables related to housing environment and mental health were selected in KoWePS' data. Data was analyzed by SPSS 19.0 and AMOS 17.0. The major results are as follow: 1) Householder economic variables significantly relate to housing environment and resident mental health. 2) Housing environment variables are significantly related to resident mental health, and these variables explain 4.3% of depression and 6.7% of self-esteem. 3) Throughout path analysis of economic, housing environment, and mental health variables, housing environment variable is a parameter. In conclusion, these results show that better quality of housing environment would contribute to the residents' better mental health.

• Molecules and Cells
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• v.41 no.7
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• pp.631-638
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• 2018

Spermatogonial stem cells (SSCs) derived from mouse testis are unipotent in regard of spermatogenesis. Our previous study demonstrated that SSCs can be fully reprogrammed into pluripotent stem cells, so called germline-derived pluripotent stem cells (gPS cells), on feeder cells (mouse embryonic fibroblasts), which supports SSC proliferation and induction of pluripotency. Because of an uncontrollable microenvironment caused by interactions with feeder cells, feeder-based SSC reprogramming is not suitable for elucidation of the self-reprogramming mechanism by which SSCs are converted into pluripotent stem cells. Recently, we have established a Matrigel-based SSC expansion culture system that allows longterm SSC proliferation without mouse embryonic fibroblast support. In this study, we developed a new feeder-free SSC self-reprogramming protocol based on the Matrigel-based culture system. The gPS cells generated using a feeder-free reprogramming system showed pluripotency at the molecular and cellular levels. The differentiation potential of gPS cells was confirmed in vitro and in vivo. Our study shows for the first time that the induction of SSC pluripotency can be achieved without feeder cells. The newly developed feeder-free self-reprogramming system could be a useful tool to reveal the mechanism by which unipotent cells are self-reprogrammed into pluripotent stem cells.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1413-1420
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• 2014

Phytate is an antinutritional factor that impacts the bioavailability of essential minerals such as $Ca^{2+}$, $Mg^{2+}$, $Mn^{2+}$, $Zn^{2+}$, and $Fe^{2+}$ by forming insoluble mineral-phytate salts. These insoluble mineral-phytate salts are hydrolyzed rarely by monogastric animals, because they lack the hydrolyzing phytases and thus excrete the majority of them. The ${\beta}$-propeller phytases (BPPs) hydrolyze these insoluble mineral-phytate salts efficiently. In this study, we cloned a novel BPP gene from a marine Pseudomonas sp. This Pseudomonas BPP gene (PsBPP) had low sequence identity with other known phytases and contained an extra internal repeat domain (residues 24-279) and a typical BPP domain (residues 280-634) at the C-terminus. Structure-based sequence alignment suggested that the N-terminal repeat domain did not possess the active-site residues, whereas the C-terminal BPP domain contained multiple calcium-binding sites, which provide a favorable electrostatic environment for substrate binding and catalytic activity. Thus, we overexpressed the BPP domain from Pseudomonas sp. to potentially hydrolyze insoluble mineral-phytate salts. Purified recombinant PsBPP required $Ca^{2+}$ or $Fe^{2+}$ for phytase activity, indicating that PsBPP hydrolyzes insoluble $Fe^{2+}$-phytate or $Ca^{2+}$-phytate salts. The optimal temperature and pH for the hydrolysis of $Ca^{2+}$-phytate by PsBPP were $50^{\circ}C$ and 6.0, respectively. Biochemical and kinetic studies clearly showed that PsBPP efficiently hydrolyzed $Ca^{2+}$-phytate salts and yielded myo-inositol 2,4,6-trisphosphate and three phosphate groups as final products. Finally, we showed that PsBPP was highly effective for hydrolyzing rice bran with high phytate content. Taken together, our results suggest that PsBPP has great potential in the animal feed industry for reducing phytates.

• Journal of Korean Neurosurgical Society
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• v.61 no.4
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• pp.494-502
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• 2018

Objective : The loosening of pedicle screws (PS) is one of the frequent problems of spinal surgery in the patients with osteoporosis. Previous studies had revealed that intermittent injection of teriparatide could reduce PS loosening by improving bone mass and quality when their patients took parathyroid hormone for a considerable duration before surgery. However, although the teriparatide is usually used after spine surgery in most clinical situations, there was no report on the efficacy of teriparatide treatment started after spine surgery. The purpose of this retrospective study was to examine the efficacy of teriparatide treatment started immediately after lumbar spinal surgery to prevent pedicle screw loosening in patients with osteoporosis. Methods : We included 84 patients with osteoporosis and degenerative lumbar disease who underwent transforaminal interbody fusion and PS fixation and received parathyroid hormone or bisphosphonate (BP) postoperatively. They were divided into teriparatide group (daily injection of $20{\mu}g$ of teriparatide for 6 months, 33 patients, 172 screws) and BP group (weekly oral administration of 35 mg of risedronate, 51 patients, 262 screws). Both groups received calcium (500 mg/day) and cholecalciferol (1000 IU/day) together. The screw loosening was evaluated with simple radiographic exams at 6 and 12 months after the surgery. We counted the number of patients with PS loosening and the number of loosened PS, and compared them between the two groups. Clinical outcomes were evaluated using visual analog scale (VAS) and Oswestry disability index (ODI) preoperatively, and at 12 months after surgery. Results : There was no significant difference in the age, sex, diabetes, smoking, bone mineral density, body mass index, and the number of fusion levels between the two groups. The number of PS loosening within 6 months after surgery did not show a significant difference between the teriparatide group (6.9%, 12/172) and the BP group (6.8%, 18/272). However, during 6-12 months after surgery, it was significantly lower in the teriparatide group (2.3%, 4/172) than the BP group (9.2%, 24/272) (p<0.05). There was no significant difference in the number of patients showing PS loosening between the teriparatide and BP groups. The teriparatide group showed a significantly higher degree of improvement of the bone mineral density (T-score) than that of BP group (p<0.05). There was no significant difference in the pre- and post-operative VAS and ODI between the groups. Conclusion : Our data suggest that the teriparatide treatment starting immediately after lumbar spinal fusion surgery could reduce PS loosening compared to BP.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.3
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• pp.170-176
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• 2017

In this paper, we proposed the miniaturized structure of the Log-Periodic Dipole Array(LPDA) antenna for PS-LTE(Pubic Safety-Long Term Evolution) service. The length of array dipole was shortened by adding a fractal tree element with iteration to the array dipole to miniaturize the LPDA antenna. As the result, the proposed LPDA antenna was reduced up to 25 %, compared a typical LPDA antenna. To validation of the proposed LPDA antenna specification, the proposed LPDA antenna is fabricated using aluminum with 1.5 mm thickness and performances are measured. Comparison between simulation result and experiment shows good agreement.

• The Korean Journal of Pain
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• v.24 no.2
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• pp.93-99
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• 2011

Background: Rocker bottom shoes (RBS) are popular among patients with different foot, leg, or back problems in Korea. Patients with knee osteoarthritis concurrent weakness in the quadriceps femoris muscle, who wear these shoes, are often assumed to develop piriformis syndrome (PS). This study was performed to improve the understanding about the effect of wearing such shoes on duration of the syndrome in knee osteoarthritis. Methods: We randomly assigned 150 patients with PS, who had used RBS daily for at least 6 months, to 2 groups, the S (stopped wearing) and K (kept wearing) groups. Both the groups were subdivided into the O and N groups, comprising patients with and without knee osteoarthritis, respectively. The effects of the treatment, including piriformis muscle injections and a home exercise program, were compared between the 2 groups by using a flexion-adduction-internal rotation (FAIR) test, a numeric rating scale (NRS), and the revised Oswestry disability index (ODI) during the 12-week follow-up. Results: The positive FAIR test ratios, mean NRS scores, and revised ODIs were higher in the KO group than the SN group from 4-12 weeks after treatment. Conclusions: RBS may extend duration of the PS in osteoarthritis patients.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.344-360
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• 2018

The purpose of this study was to investigate the influence of triggering variables, such as personal psychological variables, personal and social environmental variables, related the suicidal ideation, suicidal plan, and suicidal attempt. The subjects were participated in the $6^{th}$(2011) KoWePS. and are analyzed with the statistical program AMOS 21.0 as a calling logistic regression. The major findings were as follows: $1^{st}$, depression, self-esteem, subjective healthful status, marital violence, role of sex were related to suicidal ideation. $2^{nd}$, subjective healthful status and problem-drinking were related to suicidal plan. $3^{rd}$, problem-drinking and marital violence was negative related to suicidal attempt. Finally, on the base of this results, the social welfare implications of this study were discussed to reduce and protect suicidal ideation, suicidal plan, and suicidal attempt. and the limitations of this study and the suggestions for future studies were also presented.

• 한국노년학
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• v.38 no.4
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• pp.923-943
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• 2018

This study was conducted to verify whether gender role attitudes are related to depression in Korean older males and examine the mediating effect of family conflict coping strategies on the relationship between the two variables. In this study, The target of the study was 1,955 men aged 65 and over in the 9th wave of the Korea Welfare Panel Study (KoWePS). Frequency analysis, descriptive statistics, correlation analysis, and multiple regression analysis were performed. In addition, Bootstrapping was conducted to verify the significance of the mediating effects of family conflict coping strategies. The results of this study show that patriarchal gender role attitudes of Korean older males were found to be associated with increased risk of depression. Family conflict coping strategies play a role as a mediator for the relationship between gender role attitudes and depression. Throughout the results of this study, the restructuring of gender role attitudes and the improvement of the way of coping with family conflict were suggested as measures to alleviate the depression of the older males, and academic and practical implications were discussed.

• Korean Journal of Social Welfare Studies
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• v.48 no.4
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• pp.5-31
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• 2017

This study investigates paths among factors influencing family relationship satisfaction of person with disability using path analysis and the 11th panel data of KoWePS(Korean Welfare Panel Study). While key independent variables include employment status, assets and depression are mediators. The result of this study are as follows: First, employment status, assets, and depression are found to have direct effect on family relationship satisfaction. Second, assets are found to have direct effect on depression. Third, we found full mediating effect of assets between employment status and depression. Fourth, we found not full but partial mediating effect of depression between assets and family relationship satisfaction. Finally, we found multiple partial mediating effects of employment status and family relationship satisfaction. The findings proposed that economic education as well as asset management targeting the disabled are required and very helpful to support their family relationship satisfaction. Based on the results of this study, we need to think about the disabled-oriented asset-building programs.This study investigates paths among factors influencing family relationship satisfaction of person with disability using path analysis and the 11th panel data of KoWePS(Korean Welfare Panel Study). While key independent variables include employment status, assets and depression are mediators. The result of this study are as follows: First, employment status, assets, and depression are found to have direct effect on family relationship satisfaction. Second, assets are found to have direct effect on depression. Third, we found full mediating effect of assets between employment status and depression. Fourth, we found not full but partial mediating effect of depression between assets and family relationship satisfaction. Finally, we found multiple partial mediating effects of employment status and family relationship satisfaction. The findings proposed that economic education as well as asset management targeting the disabled are required and very helpful to support their family relationship satisfaction. Based on the results of this study, we need to think about the disabled-oriented asset-building programs.