• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1700-1703
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• 2008

The purpose of this study was to examine the effects of various mechanical stimuli for MC3T3-E1 cells. Among the several mechanical stimulations, we focused on compressive stain and ultrasound. In this study, we developed a bioreactor capable of applying controlled stimuli to scaffolds. PLLA/PCL scaffold was fabricated by using salt-leaching method. We performed dynamic cell culture using preosteoblasts MC3T3-E1 cells with 1MHz, 30mW/cm2 ultrasound and 10% of compressive strain. Result of CCK-8 analysis at 1, 4, 7, 10 days showed that mechanical stimuli had no significant effect for cell proliferation. However, those stimuli influenced ALP(Alkaline phopatase) activity, which is one of differentiation marker.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.255-262
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• 2002

In this paper, an improved multi-objective optimmum design method is proposed. And it is applied to steel frames under seismic loads. The multi-objective optimization problem is formulated with three optimality criteria, namely, minimum structural weight and maximum strain energy and stability. The Pareto curve can be obtained by performing the multi-objective optimization for multistory shear buildings. In order to efficiently solve the multi-objective optimization problem the decomposition method that separates both system-level and element-level is used. In addition, various techniques such as effective reanalysis technique with respect to intermediate variables and sensitivity analysis using an automatic differentiation (AD) we incorporated. Moreover, the relationship function among section properties induced from the profile is used in order to link system-level and element level. From the results of numerical investigation, it may be stated that the proposed method will lead to the more rational design compared with the conventional one.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.55-55
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• 2002

An alternative sigma factor as encoded by the $\sigma$$\^$B/ gene in Streptomyces coelicolor A3(2) was known to be involved in the differentiation and osmotic stress response. Protein expression profiles of wild-type and a $\sigma$$\^$B/ mutant strain of S coelicolor A3(2), which is impaired in defense against osmotic stress, were compared in the absence and presence of osmotic stress, using 2-dimentional gel electrophoresis.(omitted)

• Interaction and multiscale mechanics
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• v.1 no.3
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• pp.339-355
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• 2008

A Galerkin meshfree method is presented for analyzing shear deformable cylindrical panels. Based upon the analogy between the cylindrical panel and the curved beam a pure bending mode for cylindrical panel is rationally constructed. The meshfree approximation employed herein is characterized by an enhanced moving least square or reproducing kernel basis function that can exactly represent the pure bending mode and thus meets the requirement of Kirchhoff mode reproducing condition. The variational form is discretized using the efficient stabilized conforming nodal integration with a smoothed nodal gradient based curvature. The resulting meshfree formulation satisfies the integration constraint for bending exactness. Moreover, it is shown here that the smoothed gradient preserves several desired properties which are valid for the standard gradient obtained by direct differentiation, such as partition of nullity and reproduction of a constant strain field. The efficacy of the proposed approach is demonstrated by two benchmark cylindrical panel examples.

• Journal of Korean Academy of Nursing Administration
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• v.19 no.5
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• pp.565-577
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• 2013

Purpose: This study was done to propose an improvement in the Nursing Fee Differentiation Policy to alleviate polarization of nursing staffing level among hospitals and to rectify the confusion of legally mandated standards between the Korean Medical Law and National Health Insurance Act. Methods: The policy regulation was reconstructed related to nurse staffing standards and nurse-to-patients ratios. Data on nurse staffing grades were obtained from database of the Health Insurance Review & Assessment Service (HIRA) for the third quarter of 2010 for 44 tertiary hospitals, 274 general hospitals, and 1,262 hospitals. A break-even analysis was used to estimate financial burden of the revised policy improvement proposal. An industrial engineering method was used to calculate Nurse-to-Patients ratios per shift. Results: Twelve tertiary hospitals were downgraded. 74 general hospitals and 102 hospitals were upgraded after application of the regulation. Finances for total hospitalization expenditures changed from -3.55% to +3.14%. Conclusion: The results indicate that the proposed policy would decrease polarization between tertiary hospitals and small hospitals, and would not put a major strain on the finances of the Korean National Health Insurance. Therefore, it is suggested that government stake-holders and many interest groups consider this policy proposal and build a consensus.

• Composites Research
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• v.25 no.5
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• pp.136-140
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• 2012

This paper describes the bone healing process of fractured long bones such as a tibia applied by composite IM rods using finite element analysis. To simulated tissue differentiation process mechano-regulation theory with a deviatoric strain was implemented and a user's subroutine programmed by a Python code for an iterative calculation was used. To broadly find the appropriate rod modulus for healing bone fractures, composite IM rods were analyzed considering the stacking sequence. To compare mechanical stimulation at fracture gap, two kinds of initial loading conditions were applied. As a result, it was found that the initial loading condition was the most sensitive factor for the healing performance. In case a composite IM rod made of a plain weave carbon fiber/epoxy (WSN3k) had a stacking sequence of $[{\pm}45]_{nT}$, the healing efficiency was the most effective under a initial load of 10%BW.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.151-159
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• 2024

Bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) is one of the most severe diseases in radish cultivation. To control this plant disease, the most effective method has been known to cultivate resistant cultivars. Previously, we developed an efficient bioassay method for investigating resistance levels with 21 resistant and moderately resistant cultivars of radish against a strain Pcc KACC 10421. In this study, our research expanded to investigate the resistance of radish cultivars against six Pcc strains, KACC 10225, KACC 10421, ATCC 12312, ATCC 15713, LY34, and ECC 301365. To this end, the virulence of the six Pcc strains was determined based on the development of bacterial soft rot in seedlings of four susceptible radish cultivars. The results showed that the Pcc strains exhibited different virulence in the susceptible cultivars. To explore the race differentiation of Pcc strains corresponding to the resistance in radish cultivars, we investigated the occurrence of bacterial soft rot caused by the six Pcc strains on the 21 resistant and moderate resistant cultivars. Our results showed that the average values of the area under the disease progress curve were positively correlated with the virulence of the strains and the number of resistant cultivars decreased as the virulence of Pcc strains increased. Taken together, our results suggest that the resistance to Pcc of the radish cultivars commercialized in Korea is more likely affected by the virulence of Pcc strains rather than by race differentiation of Pcc.

• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.262-274
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• 2005

Tooth movement is a result of mutual physiologic responses between the periodontal ligament and alveolar bone stimulated by mechanical strain. The PDL cell and osteoblast are known to have an influence on bone formation by controlling collagen synthesis and alkaline phosphatase activation. Moreover. recent studies have shown that the PDL cell and osteoblast release osteoprotegerin (OPG) and the receptor activator of nuclear factor ぉ ligand (RANKL) to control the level of osteoclast differentiation and activation which in turn influences bone resorption. In this study. progressively increased, continuous tensional force was applied to PDL cells. The objective was to find out which kind of biochemical reactions occur after tensional force application and to illuminate the alveolar bone resorption and apposition mechanism. Continuous and progressively increased tensile force was applied to PDL cells cultured on a petriperm dish with a flexible membrane The amount of $PGE_2$ and ALP synthesis were measured after 1, 3, 0 and 12 hours of force application. Secondly RT-PCR analysis was carried out for OPG and RANKL which control osteoclast differentiation and MMP-1 -8, -9, -13 aud TIMP-1 which regulate the resolution of collagen and resorption of the osteoid layer According to the results. we concluded that progressively increased, concluded force application to human PDL cells reduces $PGE_2$ synthesis, and increases OPG mRNA expression.

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.15-20
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• 1996

Cysts of Entamoebn histoIMtica are still found from humans in Korea, but notall of the cysts are known as pathogenic. The non-pathogenic strain is regarded as a differenL species, E. nispnr. In this study, Korean isolates of conventional E. histolvticn were subjected for the differentiation by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Human stools were screened by routine microscopic examination, and cyst or trophozoite positive stools were inoculated into Robinson media. The cultivated trophozoites were prepared for DNA extraction, and the DNAs were used for PCR with common primers of Pl gene. The PCR products were divested with 3 restriction enzymes and RFLP was observed. Also anti-sense primers containing the cleavage site of each restriction eWe were designed for differentiation only by PCR. The PCR products of Korean isolates 59,512, YS-6, and YS-27 were spliced by Taq I and Xmnl but not byAccl, and the isolates S1, S3, S11, S15, S16, S17, S20, YS- l7, and YS-44 were spliced by Acc I but not by Taq I and Xmn I. These RFLP pattern correlated well with PCR products by the species specific primers. The findings confirm that the Korean isolates 59,512, YS-6, and YS-27 are E. histolwtico and others are E. dispar. In Korea, most of the asymptomatic cyst carriers are infected by E. dispar, not by E. histolytica. Key words: Entcmoebc histolytica, Entcmoebn dispar Korean isolates, polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP)

• Archives of Pharmacal Research
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• v.18 no.2
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• pp.90-99
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• 1995

The effect of protein kinase C inhibitors, sturosporine and 1-(5-isoquinolinyl sulfonyl)-2-methyl piperazine(H7) on in vitro differentiation of erythroid progenitor cells which were isolated from spleens of mice infected with the anemia-inducing strain of Friend virus were examined. Erythropoietin-mediated differentitation of erythroid progenitor cells, as determined by the incorporation of $^{59}Fe$ into protoporphyrin, was inhibited by staurosporine and H7 in a concentration -dependent manner. Scatchard analysis of the $^3H-phorbol-12$, 13-dibutyrate binding to erythroid progenitor cells revealed that at the high affinity sites the dissociation constant was 22nM and the maximum number of $^3H-phorbol-12$, 13-dibutyrate binding to erythroid progenitor cells revealed that at the high affinity sites the dissociation constant was 22nM and the maximum number of $^3H-phorbol-12$, 13-dibutyrate binding sites per cell was approximately $3.7\times10^5$. Cytosonic protein kinase C was isolated from erthroid progenitor cells and then purified by sequential column chromatogrphy. Two isoforms of protein kinase C were found. Photoaffinity labeling of the purified protein kinase C samples with $^3H-phorbol-12$12-myristate 13-acetate followed by analysis of SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and autofluorography showed radiolabeled 82-KDa pepticles. Rediolabeling of the 82-KDa peptides with $^3H-phorbol-12$myristate 13-acete was almost completely blocked by excess unlabeled phorbol 12-myristate 13-acetate was almost 12-muristate 13-acetate-promoted phosphorylation with the puyrified protein kinase C samples showed that the phosphorylation of 82-KDa peptides was increased as the concentration of phorbol 12-myristate 13-acetate was increased from $10^{-8}M{\;}to{\;}10^{-4}$M. In light of the findings that erythroid progenitor cells possessed an abundance of protein kinase C and that stauroporine and H7 inhibited erythroid differentiation, it seemed likely that protein kinase C would play a role in the erythroid progenitor cell development.