• Journal of Life Science
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• v.17 no.6 s.86
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• pp.783-790
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• 2007

G protein coupled receptors (GPCRs) transmit various extracellular signals into the cells. Upon binding of the ligands, conformational changes in the extracellular and/or transmembrane (TM) domains of CPCRs were propagated into the cytoplasmic (CP) domain of the molecule leading to the activation of their cognate heterotrimeric C proteins and kinases. Constitutively active GPCR mutants causing the activation of C Protein signaling even in the absence of ligand binding are of interest for the study of activation mechanism of GPCRs. Two classes of constitutively active mutations, categorized by their effects on the salt bridge between Ell3 and K296, were found in the TM domain of rhodopsin. Opsin mutants containing combinations of the mutations were constructed to study the conformational changes required for the activation of rhodopsin. Rhodopsin chromophore regenerated with 11-cis-retinal showed a thermal stability inversely correlated with its constitutive activity. In contrast, rhodopsin mutants exhibited a binding affinity to an agonist, all-trans-retinal, in a constitutive activity-dependent manner. In order to test whether the conformational changes responsible for the activation of trans-ducin (Gt) are the same as the conformation required for the recognition of rhodopsin kinase, analysis of the mutants were carried out with phosphorylation by rhodopsin kinase. Rhodopsin mutants containing combinations of different classes of the mutations showed a strong synergistic effect on the phosphorylation of the mutants in the dark as similar to that of Gt activation. The results suggest that at least two or three kinds of segmental and independent conformational changes are required for the activation of rhodopsin and the conformational changes responsible for activating rhodopsin kinase and Gt are similar to each other.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.1
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• pp.43-53
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• 1992

The purpose of this study was to investigate the effects of irradiation on the microvascular structure of the submandibular gland in rats. For this study, 110 male rats were singly irradiated with the dose of 10Gy or 20Gy to their neck region by 6MV X-irradiation and sacrificed on the 1st, 3rd, 7th, 14th and 28th day after irradiation. The author observed distribution and structural changes of the microvasculature in rat submandibular glands using a scanning electron microscope by forming vascular resin casting. The author observed ultrastructural changes of the endothelial cells using a transmission electron microscope, and also histologic changes using a light microscope at Hematoxylin and Eosin staining and PAS staining process. The results of the irradiation effects on the microvasculature in rat submandibular gland were as follows: By light microscopic examination, the dilation of small vessels were observed until the 7th day after irradiation. After then, the vascular constriction and decrease in number of small vessels were noticed. Changes were greater on 20Gy irradiated group than on lOGy irradiated group. The reaction to PAS staining at acinar cells was decreased just after irradiation, but gradually recovered with days. There was no specific difference between two irradiated groups. By scanning electron microscopic examination, general findings on the two irradiated groups were similar. The dilation of conduits and meandering were observed on the 3rd day after irradiation. Decrease of capillary density and blunt ended small vessels were appeared on the 7th day after irradiation. After that, findings of the tortuous and twisted vascular running and coarseness of capillary lumen were increased. Changes were greater on 20Gy irradiated group than on l0Gy irradiated group. By transmission electron microscopic examination, increase of the formation of cytoplasmic process was observed on the 3rd day after irradiation. After that, swelling of endothelial cell and bridge formation of cytoplasmic processes were also observed, but destruction of endothelial cell and loss of basement membrane were observed only on 20Gy irradiated group on the 28th day after irradiation.

• Journal of Periodontal and Implant Science
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• v.41 no.6
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• pp.293-301
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• 2011

Purpose: We have previously reported that tetra-cell adhesion molecule (T-CAM) markedly enhanced the differentiation of osteoblast-like cells grown on anorganic bone mineral (ABM). T-CAM comprises recombinant peptides containing the Arg- Gly-Asp (RGD) sequence in the tenth type III domain, Pro-His-Ser-Arg-Asn (PHSRN) sequence in the ninth type III domain of fibronectin (FN), and the Glu-Pro-Asp-Ilu-Met (EPDIM) and Tyr-His (YH) sequence in the fourth fas-1 domain of ${\beta}$ig-h3. Therefore, the purpose of this study was to evaluate the cellular activity of osteoblast-like cells and the new bone formation on ABM coated with T-CAM, while comparing the results with those of synthetic cell binding peptide (PepGen P-15). Methods: To analyze the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, andto analyze gene expression, northernblot was performed. Mineral nodule formations were evaluated using alizarin red stain. The new bone formations of each group were evaluated using histologic observation and histomorphometrc analysis. Results: Expression of alkaline phosphatase mRNA was similar in all groups on days 10 and 20. The highest expression of osteopontin mRNA was observed in the group cultured with ABM/P-15, followed by those with ABM/T-CAM and ABM on days 20 and 30. Little difference was seen in the level of expression of collagen type I mRNA on the ABM, ABM/T-CAM, and ABM/P-15 cultured on day 20. There were similar growth and proliferation patterns for the ABM/T-CAM and ABM/P-15. The halo of red stain consistent with $Ca^{2+}$ deposition was wider and denser around ABM/T-CAM and ABM/P-15 particles than around the ABM particles. The ABM/T-CAM group seemed to have bone forming bioactivity similar to that of ABM/P-15. A complete bony bridge was seen in two thirds of the defects in the ABM/T-CAM and ABM/P-15 groups. Conclusions: ABM/T-CAM, which seemed to have bone forming bioactivity similar to ABM/P-15, was considered to serve as effective tissue-engineered bone graft material.

• The Journal of the Korea Contents Association
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• v.14 no.10
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• pp.741-753
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• 2014

The objective of the study is to explore how to influence SNS's characteristics on attitude formation toward jewelry product and online shopping mall. SNS's characteristics are contextuality, responsiveness, social presence, and interaction as independent variables. Consumer satisfaction, worth of mouth and purchase intention are considered as dependent variables. Data were collected from a survey of 317 consumers who have experience to purchase jewelry product to examine their attitude toward SNSs, jewelry product, and online shopping mall from November 1 to November 15 2013. In order to test hypotheses, CFA analysis with covariance structure analysis was conducted using EQS6b. SNS's users have a tendency to perceive SNSs as bridge to connect other people and to get new information as well as they are willing to feel familiarity on SNSs. Users, who have a higher contextuality, responsiveness, social presence, and interaction of SNS's characteristics, are willing to have word of mouth intention of jewelry product as well as have high satisfaction. The study found that interaction is not effect on consumer satisfaction because interaction factor is to evaluate SNSs as one of the media.

• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.543-549
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• 2004

Chitosan has been widely researched as bone substitution materials and membranes in orthopedic/periodontal applications. Chitosan nanofiber membrane was fabricated by chitosan nanofiber using electrospinning technique. The structure of the membrane is nonwoven, three-dimensional, porous, and nanoscale fiber-based matrix. The aim of this study was to evaluate the biocompatibility of chitosan nanofiber membrane and to evaluate its capacity of bone regeneration in rabbit calvarial defect. Ten mm diameter round cranial defects were made and covered by 2 kinds of membranes (Gore-Tex membrane, chitosan nanofiber membrane) in rabbits. Animals were sacrificed at 4 weeks after surgery. Decalcified specimens were prepared and observed by microscope. Chitosan nanofiber membrane maintained its shape and space at 4 weeks. No inflammatory cells were seen on the surface of the membrane. In calvarial defects, new bone bridges were formed at all defect areas and fused to original old bone. No distortion and resorption was observed in the grafted chitosan nanofiber membrane. However bone bridge formation and new bone formation at the center of the defect could not be seen in Gore-Tex membranes. It is concluded that the novel membrane made of chitosan nanofiber by electrospinning technique may be used as a possible tool for guided bone regeneration.

• Journal of Photoscience
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• v.9 no.2
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• pp.534-536
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• 2002

A halophilic archaeon, Halobacterium salinarum, exhibits phototactic behaviors, by which the organism is guided to red-orange light and evades shorter wavelengths of light. The phototaxis is mediated by two retinal proteins, sensory rhodopsin I and II (SRI and SRII), whose structures are analogous to the cognate protein bacteriorhodopsin, a light-driven proton pump. SRI mediates both attractant and repellent swimming behaviors to orange light and near- UV light, respectively. The two different signaling through the single photoreceptor have been ascribed to the presence of two active structures of SRI (S$\_$373/ and P$\_$520), which are produced upon orange light illumination of SRI and upon subsequent near-UV illumination of S$\_$373/, respectively. In the present study, we have measured the difference FTIR spectra of S$\_$373/ and P$\_$520/ states. In P$\_$520/, the isomeric structure of the chromophore is assignable to all-trans, and the Schiff base of the chromophore is protonated with concomitant deprotonation of Asp76, a combination which allows for the formation of a salt bridge between them. It was suggested that the way of interaction between the Schiff base and the counterion, which is different among SRI$\_$587/, S$\_$373/ and P$\_$520/ and which has been shown to drive the conformational changes in the cognate protein, bacteriorhodopsin, is the key to controlling conformational changes for the attractant and the repellent signaling by SRI.

• Geomechanics and Engineering
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• v.7 no.5
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• pp.495-524
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• 2014

To investigate the soil-pile interactive performance under lateral loads, a set of laboratory model tests was conducted on remoulded test bed of soft clay and medium dense sand. Then, a simplified boundary element analysis had been carried out assuming floating pile. In case of soft clay, it has been observed that lateral loads on piles can initiate the formation of a gap, soil heave and the tension crack in the vicinity of the soil surface and the interface, whereas in medium dense sand, a semi-elliptical depression zone can develop. Comparison of test and boundary element results indicates the accuracy of the solution developed. However, in the boundary element analysis, the possible shear stresses likely to be developed at the interface are ignored in order to simplify the existing complex equations. Moreover, it is unable to capture the influence of base restraint in case of a socketed pile. To bridge up this gap and to study the influence of the initial stress state and interface parameters, a field based case-study of laterally-loaded pile in layered soil with socketed tip is explored and modelled using the finite element method. The results of the model have been verified against known field measurements from a case-study. Parametric studies have been conducted to investigate the influence of the coefficient of lateral earth pressure and the interface strength reduction factor on the results of the model.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.2
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• pp.125-132
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• 2004

Statements of problem: All ceramic fixed partial denture cores can be made by the slip casting method and the advanced alumina tape method. The fracture resistance of these core connector areas is relatively low. Purpose: The purpose of this study is to standardize the appropriate volumetric figure and location of the connectors in the alumina core fabricated in alumina tape to be used in fixed partial dentures by way of topology optimization. Material and method: A maxillary anterior three-unit bridge alumina core with teeth form and surrounding periodontal apparatus model was used to ultimately design the most structurally rigid form of the connector. Loadings from a $0^{\circ}$, $45^{\circ}$ and $60^{\circ}$ to the axis of each tooth were applied and analyzed with the 3-D finite element analysis method. Using the results from these experiments, the topology optimization was applied and the optimal reinforcement layout of connector was obtained and the detail shape in the fixed partial denture core was designed. Results: The modified prosthesis with the form of a bulk in the lower lingual surface of the connector in the event, reduced the stress concentration up to 20% in the 3-D FEA. Conclusion: The formation of a bulk in the lower lingual connector area of an alumina core for a fixed partial denture decreases the stress to a clinically favorable measure but does not harm the esthetic point of view. This result illustrates the possibility of clinical application of the modified form designed by the topology optimization method.

• BMB Reports
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• v.35 no.5
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• pp.524-531
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• 2002

Thrombotic thrombocytopenic purpura (TTP) is characterized by widespread platelet thrombi in arterioles and capillaries. Unusually large or multimeric von Willebrand factor, as well as one or ore platelet-agglutinating factors, have been implicated in the pathogenesis of TTP. But, the actual mechanisms of platelet agglutination have not been satisfactorily explained. Recent studies suggested the 37-kDa platelet-agglutinating protein (PAP) p37 to be partially responsible for the formation of platelet thrombi in patients with TTP. We studied mobility in SDS-PAGE, the sequence of N-terminal amino acid residues, DNA and antigenic characteristics of PAP p37, which might be related to the pathogenesis of TTP. PAP p37 was purified from the plasma of a 31-year-old male Korean patient with acute TTP. The findings are as follows: (1) We compared PAP p37 with thrombin through the use of SDS-PAGE, either with or without $\beta$-mercaptoethanol. PAP p37 did not appear to be cleaved between the A- and B-chains of prethrombin 2. However, thrombin did cleave between those of prethrombin 2, but linked with disulfide bridge. (2) N-terminal 21 amino acid sequence of PAP p37 was T-F-G-S-G-E-A-D-X-G-L-R-P-L-F-E-K-K-S-L-E. It appeared to be identical to that of 285-305 amino acid residues of human prothrombin (prethrombin 2). (3) No prothrombin gene DNA mutation was revealed. (4). The antigenicity of PAP p37 was similar to thrombin, which was a result of the competitive binding against the anti-thrombin antibody. With these results, we conclude that PAP p37 has similar characteristics to prethrombin2.

• Korean Institute of Interior Design Journal
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• no.11
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• pp.11-19
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• 1997

This stduy aimed to suggest a possible way for a new setting of interior design education through analyzing educational situations of domestic interior design societies. The study showed that interior design education should not follow expressive methods made from practical work which had been popular in the past and it should establish fundamental formation to make interior design education useful in industrial fields through active educationalindustrial complex. Interior design education is not possible without interrelationship with other professional fields and cooperative attitudes among them. The rapid development in the modern industrial world and the ever-growing information processing world regardless of ideology and regiional boundaries indicate that the future of interior design education will be no longer effective with traditional education systems. The idea suggested in this study may be understood as a bridge between the educational reality and its ideal in interior design teaching. The main points of the study are follows. First, the projects of advanced interior design should be focused on increasing the ability for problem solving rather than accumulating basic knowledge. Second, motivation is important for the maximization of the efficiency of educatiov. Therefore a few suggestions in establishing design conditions, as strategies of inducing 'attention', 'self-confidence', 'satisfaction', and 'relevance' are closely examined to propose practical application methods. Third, educational methods should be developed towards creativity in order to increase abilities of thinking and expressiov. Finally, it is necessary to explore various device which help internship participants to get experiences with a sense of practical situations in industrial fields. This could be possibly done by enforcing academic grades for the work done as an internship participation; by employing workmen in industrial fields as faculty members; and by bringing faculty members into actual industrial situations and providing workmen with lectures. A new approach for a better design education seems to be desirable for the future.