• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1365-1374
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• 2014

Thirteen analogs of tridecapeptide ${\alpha}$-factor (WHWLQLKPGQPMY) of Saccharomyces cerevisiae with C- or N-terminal Trp extension and isosteric replacement by Aib at position 8 and 11, Trp at position 13, D-Ala at position 9, and Orn and Glu at position 6 were synthesized and assayed for their biological activity. Receptor binding assay was carried out using our newly developed spectrophotometric method with detector peptide 14. C- or N-terminal extended analogs, ${\alpha}$-factor-$[Trp]_n$ (n =1-5) 1-5 and $[N-Trp]_1$-${\alpha}$-factor 6, were all less active than native ${\alpha}$-factor and gradual decreases in both activity and receptor affinity were observed with greater Trp extension. Trp-substituted analog at position 13, $[Trp^{13}]{\alpha}$-factor 7, exhibited about 2-fold reductions in both activity and receptor affinity. Aib-substituted analogs, $[Aib^8]{\alpha}$-factor 8 and $[Aib^{11}]{\alpha}$-factor 9, showed 5- to 10-fold reduction in activity as well as 3-fold reduction in receptor affinity compared to native ${\alpha}$-factor. $[Orn^6]{\alpha}$-factor 10 demonstrated strong potency with a 7.0-fold increase in halo activity as well as 1.8-fold increase in receptor affinity compared to native ${\alpha}$-factor. For two double substituted analogs, [$Glu^6,{\small{D}}-Ala^9$]${\alpha}$-factor 12 showed the slightly decreased potency in halo activity compared to analog 10, whereas [$Orn^6,{\small{D}}-Ala^9$]${\alpha}$-factor 11 exhibited 15-fold higher halo activity as well as nearly 3-fold higher receptor affinity compared to native ${\alpha}$-factor.

• Journal of Korean Neurosurgical Society
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• v.30 no.3
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• pp.366-370
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• 2001

Objective : The authors present three cases of brain tumors in which epidural hematomas(EDHs) were developed postoperatively in the remote areas from craniotomy sites. The preventive tactics as well as possible mechanisms of development of remote EDH are discussed. Material and Methods : The magnetic resonance imagings of three patients revealed a left lateral ventricular mass located just aside of foramen Monro in a 27-year-old male, a large cystic mass in the temporal lobe in a 35-year-old male, and a partially calcified pineal mass in a 27-year-old male patient. The surgical removals of these tumors were performed without any noticeable events during surgery via left frontal transcortical transventricular approach for lateral ventricular tumor, left temporal craniotomy for cystic temporal tumor, and right occipital transtentorial approach for pineal tumor. Results : Postoperative EDHs remote from the sites of craniotomy were detected by the immediate postoperative computerized tomographic scans. We obtained good outcomes without any morbidity in all three patients with emergent evacuation of the hematoma. The pathologic diagnoses were lateral ventricular ependymoastrocytoma, temporal craniopharyngioma and mixed germinoma of the pineal region. Conclusion : It is postulated that a sudden reduction of intracranial pressure(ICP) at the time of tumor removal may strip the dura from the inner table of the skull to cause EDH from the remote site of craniotomy. Gradual reduction of ICP with slow drainage of cerebrospinal fluid before tumor removal as well as lowering the head position of patient during surgery might be helpful for preventing this unusual complication.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1398-1408
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• 2003

Tensile and LCF(low cycle fatigue) tests were carried out in air at wide temperature range 20$^{\circ}C$-750$^{\circ}C$ and strain rates of 1${\times}$10$\^$-4//s-1${\times}$10$\^$-2/ to ascertain the influence of strain rate on tensile and LCF properties of prior cold worked 316L stainless steel, especially focused on the DSA(dynamic strain aging) regime. Dynamic strain aging induced the change of tensile properties such as strength and ductility in the temperature region 250$^{\circ}C$-600$^{\circ}C$ and this temperature region well coincided with the negative strain rate sensitivity regime. Cyclic stress response at all test conditions was characterized by the initial hardening during a few cycles, followed by gradual softening until final failure. Temperature and strain rate dependence on cyclic softening behavior appears to result from the change of the cyclic plastic deformation mechanism and DSA effect. The DSA regimes between tensile and LCF loading conditions in terms of the negative strain rate sensitivity were well consistent with each other. The drastic reduction in fatigue resistance at elevated temperature was observed, and it was attributed to the effects of oxidation, creep and dynamic strain aging or interactions among them. Especially, in the DSA regime, dynamic strain aging accelerated the reduction of fatigue resistance by enhancing crack initiation and propagation.

• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.399-408
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• 2001

Tooth bleaching has been prevailing recently for its ability to recover the color and shape of natural teeth without reduction of tooth material. However, it has been reported that bleaching procedure adversely affects the adhesive bond strength of composite resin to tooth. At the same time the bond strength was reported to be regained by application of some chemical agents. The purpose of this in vitro study was to investigate the effect of the removal of residual peroxide on the composite- enamel adhesion and also evaluated fracture mode between resin and enamel after bleaching. Sixty extracted human anterior and premolars teeth were divided into 5 groups and bleached by combined technique using of office bleaching with 35 % hydrogen peroxide and matrix bleaching with 10% carbamide peroxide for 4 weeks. After bleaching, the labial surfaces of each tooth were treated with catalase, 70% ethyl alcohol, distilled water and filled with composite resin. Shear bond strength was tested and the fractured surfaces were also examined with SEM. Analysis revealed significantly higher bond strength values. (p＜0.05) for catalase-treated specimens, but water-treated specimens showed reduction of bond strength, alcohol- treated specimens had medium value between the two groups(p＜0.05). The fracture mode was shown that the catalase group and the alcohol group had cohesive failure but the water sprayed group had adhesive failure. It was concluded that the peroxide residues in tooth after bleaching seems to be removed by gradual diffusion and the free radical oxygen from peroxide prevents polymerization by combining catalyst in the resin monomer. Therefore it may be possible to eliminate the adverse effect on the adhesion of composite resin to enamel after bleaching by using water displacement solution or dentin bonding agent including it for effective removal of residual peroxide.

• Journal of the Korea Concrete Institute
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• v.23 no.6
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• pp.817-826
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• 2011

Concrete using eco-cement has a problem with long-term strength development. However, currently, a long-term strength development mechanism is not confirmed, resulting in a lack of application of eco-cement in construction fields. In this study, the curing humidity influence on development in long-term strength of concrete using eco-cement and the relationship between strength and pore structure were examined. The results showed that wet cured eco-cement with a high water/cement ratio showed serious long-term strength reduction due to non-reduction of pore volume (pore size over 10 nm) in mortar caste with eco-cement. Also, the study results on improvement of long-term strength of eco-cement by partial replacement with ordinary portland cement and finely-ground fly ash showed that both of these alternatives improved long-term strength of concrete caste with eco-cement due to gradual refinement of their micro-structure.

• Asia-Pacific Journal of Business
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• v.11 no.2
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• pp.133-143
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• 2020

Purpose - This study seeks to summarize the tax changes in stock trading and analyze K-OTC stock trading data in 2017 and 2018 to infer the effects of the application of capital gains taxes by individual investors. Design/methodology/approach - This study analyzes the case of the expansion of the 2018 capital gains tax exemption in the K-OTC market, which exempts capital gains tax on the proceeds from the sale of individual investors of certain stocks under the temporary special law. Findings - In the K-OTC market, the amount of transactions has expanded since the capital gains tax exemption in 2018, but the volume of transactions and transaction turnover have decreased. In particular, the result of lower transaction turnover after the expansion is contrary to expectations. To control the macroscopic effects of the stock market, further analyses the transactions of capital gains tax-exempt stocks and non-exempt stocks. The turnover rate of exemption stocks is higher than that of the non-exempt stocks. In the case of transaction turnover, the two results are not consistent. However, the latter result is more meaningful because the comparison of exempt and non-exempt reduces distortion by macro effects. Research implications or Originality - To mitigate the impact of capital gains taxes on stock market, government authorities need to consider the gradual expansion of the scope of taxation, the application of separate taxation in the introduction of capital gains, the reduction tax rate on transfer income of listed shares, and the reduction tax rate on long-term holdings.

• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.282-288
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• 2003

It is known that HIV (Human Immunodeficiency Virus) infection, which causes AIDS after some latent period, is a dynamic process that can be modeled mathematically. Effects of available anti-viral drugs, which prevent HIV from infecting healthy cells, can also be included in the model. In this paper we illustrate control theory can be applied to a model of HIV infection. In particular, the drug dose is regarded as control input and the goal is to excite an immune response so that the symptom of infected patient should not be developed into AIDS. Finite horizon optimal control is employed to obtain the optimal schedule of drug dose since the model is highly nonlinear and we want maximum performance for enhancing the immune response. From the simulation studies, we found that gradual reduction of drug dose is important for the optimality. We also demonstrate the obtained open-loop optimal control is vulnerable to parameter variation of the model and measurement noise. To overcome this difficulty, we finally present nonlinear receding horizon control to incorporate feedback in the drug treatment.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.144-151
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• 2016

With an aging population in rural areas, farm owners in South Korea are also aging. In particular, this phenomenon leads to the lack of human resources in rural areas and agriculture, worsening the deterioration of the rural economy. This study aimed, firstly, to analyze the criticality of the lack of human resources and high production cost issues for farmers, before using the farm as cooperative nursery of rice seedlings. Secondly, the study analyzed farmer satisfaction after using the farm cooperative. Analysis results are as follows. The motives of the research subjects for using the co-nursery were the aging of the farming population, the expected reduction of production costs, and farmers' failure in raising seedlings. Importance-performance analysis measured the importance for the farms for cooperative raising of rice seedling at 3.49 and the performance for the farms at 3.41, with a difference of 0.07 between them. The four importance-performance matrix areas, used were as follows: concentrated efforts required (Quadrant I: concentrate here), continuous maintenance (Quadrant II: keep up the good work), gradual improvement (Quadrant III: low priority), and avoiding excessive efforts (Quadrant IV: possible overkill). Based on the results, it was concluded that improvements and efforts would be necessary for each of these areas. And, there is a need to improve services through the initiation of farmer use of this rice co-nursery.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1951-1956
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• 2003

It is known that HIV (Human Immunodeficiency Virus) infection, which causes AIDS after some latent period, is a dynamic process that can be modeled mathematically. Effects of available anti-viral drugs, which prevent HIV from infecting healthy cells, can also be included in the model. In this paper we illustrate control theory can be applied to a model of HIV infection. In particular, the drug dose is regarded as control input and the goal is to excite an immune response so that the symptom of infected patient should not be developed into AIDS. Finite horizon optimal control is employed to obtain the optimal schedule of drug dose since the model is highly nonlinear and we want maximum performance for enhancing the immune response. From the simulation studies, we find that gradual reduction of drug dose is important for the optimality. We also demonstrate the obtained open-loop optimal control is vulnerable to parameter variation of the model and measurement noise. To overcome this difficulty, we finally present nonlinear receding horizon control to incorporate feedback in the drug treatment.

• Journal of Nutrition and Health
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• v.36 no.6
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• pp.589-602
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• 2003

This study was designed to investigate the effects of weight reduction and changes in serum lipid composition using a commercial uncooked powdered food (UPF) diet on 27 obese hyperlipidemic women over a period of 12 weeks. We replaced the standard breakfast and dinner of each of the subjects with UPF. Their dietary intake status was evaluated by 24-hour recall method. Their body compositions were measured using a body fat analyzer. Also, we conducted hematological, clinical and lipid profile analyses of their blood. Their intake of energy, lipid and protein significantly decreased as the subjects started to take UPF, but their intake of vitamins and minerals, other than iron, increased. Due to the energy intake decrease, the subjects' weight, body fat and waist circumference significantly decreased. Among the lost weight the percentage of the body fat was high. We judged that this process of losing weight was successful in obese hyperlipidemic women. Serum HDL-cholesterol gradually increased and serum total-cholesterol, LDL-cholesterol, triglyceride levels showed gradual decreases. When obese hyperlipidemic women replaced two of three meals with UPF for 3 months, we were able to see useful changes like decreased body fat and serum lipid. Complete judgment on the usefulness of UPF may be difficult but if people take a standard meal once a day and replenish their iron by taking UPF twice a day, we assume that replacing UPF with balanced regular meal not be a problem in nutritional status. Our results show that UPF is effective in the diet therapy of obese hyperlipidemic women.