• Journal of Ecology and Environment
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• v.35 no.2
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• pp.123-129
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• 2012

Salt marsh is an important transitional zone among terrestrial, riverine, and marine ecosystems and is a productive habitat that interacts extensively with adjacent landscape elements of estuarine and coastal ecosystems. Nowadays, in addition to various human activities, a variety of natural processes induce changes in salt marshes. This study aims to provide background information to restore disturbed salt marshes and to propose their ecological restoration using seed banks. The study area is a prepared area for the Gwangyang Container Port located in the southern Korea. This area was formed by accumulating mud soils dredged from the bottom of the forward sea. This land was created in a serial process of preparing the Gwangyang container port and the salt marsh was passively restored by seeds buried in mud soil dredged from seabed. As a result of stand ordination based on vegetation data collected from the land, stands were arranged according to tolerance to salinity in the order of $Suaeda$ $maritima$, $Salicornia$ $europaea$, and $Phragmites$ $communis$ communities on the Axis 1. Landscape structure of the projected area was analyzed as well. Edges of the projected area were divided from the marginal waterway by the dike. Four types of vegetation appeared on the dike: $Alnus$ $firma$ plantation, $Robinia$ $pseudoacacia$ plantation, $Lespedeza$ $cyrtobotrya$ plantation, and grassland. In the more internal areas, two types of vegetation sequences appeared: $Aster$ $tripolium$ community-$Suaeda$ $glauca$ community-$Salicornia$ $europaea$ community sequence and $Aster$ $tripolium$ community-$Suaeda$ $maritima$ community-$S.$ $europaea$ community sequence. Mixed community showed the highest species diversity (H' = 0.86) and $S.$ $europaea$ community showed the lowest (H' = 0.0). Evenness is the highest in Mixed community (J' = 2.26) and the lowest in $S.$ $maritime-S.$ $europaea$ community (J' = 0.0). Several plant communities were successfully established on the land created by mud soil dredged from the bottom of Gwangyang Bay. Moreover, community diversity in this area approached a similar level with those from other studies involving natural salt marshes. Therefore, restoration effect based on community diversity obtained in our study can be evaluated as a successful achievement. In this respect, although most salt marshes in Korea and other places worldwide have been destroyed or disturbed by excessive land use, feasibility of seed bank as a restoration tool is greatly expected.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.4
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• pp.232-238
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• 2003

This study was performed to evaluate the effect of topical and intravenous heparin on thrombosis and patency in the microvascular anastomosis of the traumatized veins. Nine white rabbits weighing about 2 kg were used. After exposure of both femoral veins, the veins were crushed by the jaws of smooth needle holder in order to create a thrombosis model. Transectional incision was made in the vein. The animals were then divided into 3 groups based on the administration method of heparin: 1) Experimental Group I, topical irrigation of lumen with heparin saline solution (n=6); 2) Experimental Group 2, topical irrigation of lumen with heparin saline solution and intravenous injection of heparin (0.75 mg/kg) via the marginal ear vein for 3 days; 3) Control Group, topical irrigation of lumen with saline solution (n=6). The patency was evaluated with empty-and-refill test and thrombus formation was judged by surgical microscope. The results were as follows: 1. Thirty minutes after microvascular anastomosis, the patency of all Experimental Groups was better than Control group. However, there was no significant difference among groups. 2. Three days after anastomosis, the patency of all Experimental Groups was much more improved than that of Control Group (P<0.05). There was no significant difference between Experimental Group 1 and 2. 3. Three days after anastomosis, the amount of thrombus in all Experimental Groups was much less than that of Control Group (P<0.05). 4. In histologic findings a lot of luminal thrombus were observed around sutured area in Control Groups. Few luminal thrombus was observed in all Experimental Groups. Mild necrosis in the vessel wall was observed around sutured area in all specimens. These results indicate that topical irrigation of heparin may improve the patency and inhibit the formation thrombus in the microvascular anastomosis of the traumatized veins.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.654-664
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• 2006

Statement of problem: There has been a eat interest in the use of titanium for fixed and removable prostheses in recent because of its excellent biocompatibility. However, the melting temperature and chemical reactivity of titanium necessities casting system different from those used in conventional casting. The current titanium casting systems are based on an electric-arc design for melting the metal in an argon atmosphere and its exclusive investment. Despite the new development in Ti casting system, inadequate mold filling and internal porosity are frequently observed casting defects. Purpose : The purposes of this study were to compare the castibility and reaction layer of the casting titanium under the two casting machines and their investment condition. Material and method: coping and machine-milled titanium coping according to the casting methods and the marginal configurations. The total 28 specimens were used, and these are divided into 4 groups according to 2 casting machines and 2 investments. The castings were analyzed using x-ray microanalysis and microhardness testing. The reaction layer between margin of titanium casting and the investments was observed and analyzed with scanning electron microscope. Result: 1. Castabiliy of casting titanium specimen was best in the group of centrifugal casting machine and Selevest $CB^{\circledR}$ and good that of Selevest CB and pressure differential casting machine, Rematitan plus and centrifugal casting machine, Rematitan plus and pressure differential casting machine in order. 2. There was no significanct correlation in titanium castability in respect of casting machine. However ANOVA indicated that Selevest $CB^{\circledR}$ groups had significantly better castability than Rematitan $plus^{\circledR}$ groups.(p<0.05) 3. There was a significant microhardness difference between centrifugal casting machine groups and pressure differential groups.(p<0.05) Titanium castings in centifugal groups had significantly harder than those in pressure differential groups. 4. The addition of zirconia decreased interfacial reactivity. Conclusion: above result revealed that of the castability of titanium casting specimens had little correlation in casting machines and was better in magnesia-based investment contained ZrO2 groups. However in order to practice casting titanium in clininic, its castability should be improved, also there should be more research on factor of castability so that long-span prothesis and removable partial denture metla frame may be casted completly.

• Journal of Periodontal and Implant Science
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• v.44 no.5
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• pp.235-241
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• 2014

Purpose: Regulatory T cells (Tregs), expressing CD4 and CD25 as well as Foxp3, are known to play a pivotal role in immunoregulatory function in autoimmune diseases, cancers, and graft rejection. Dendritic cells (DCs) are considered the major antigen-presenting cells (APCs) for initiating these T-cell immune responses, of which $CD103^+$ DCs are derived from precursor human peripheral blood mononuclear cells (PBMCs). The aim of the present study was to evaluate the capacity of these PBMC-derived $CD103^+$ DCs to promote the differentiation of antigen-specific Tregs. Methods: Monocyte-derived DCs were induced from $CD14^+$ monocytes from the PBMCs of 10 healthy subjects. Once the $CD103^+$ DCs were purified, the cell population was enriched by adding retinoic acid (RA). Peptide numbers 14 and 19 of Porphyromonas gingivalis heat shock protein 60 (HSP60) were synthesized to pulse $CD103^+$ DCs as a tool for presenting the peptide antigens to stimulate $CD3^+$ T cells that were isolated from human PBMC. Exogenous interleukin 2 was added as a coculture supplement. The antigen-specific T-cell lines established were phenotypically identified for their expression of CD4, CD25, or Foxp3. Results: When PBMCs were used as APCs, they demonstrated only a marginal capacity to stimulate peptide-specific Tregs, whereas $CD103^+$ DCs showed a potent antigen presenting capability to promote the peptide-specific Tregs, especially for peptide 14. RA enhanced the conversion of $CD103^+$ DCs, which paralleled the antigen-specific Treg-stimulating effect, though the differences failed to reach statistical significance. Conclusions: We demonstrated that $CD103^+$ DCs can promote antigen-specific Tregs from naive T cells, when used as APCs for an epitope peptide from P. gingivalis HSP60. RA was an effective reagent that induces mature DCs with the typical phenotypic expression of CD103 that demonstrated the functional capability to promote antigen-specific Tregs.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.372-378
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• 2007

This study was carried out to investigate the effect of potassium concentrations in fertigation solution on growth and development of nutrient deficiency symptoms of leaf perilla (Perilla frutesens). The nutrient concentrations in above ground plant tissue, petiole sap and soil solution of root media were also determined. Potassium deficiency symptoms developed in older leaves with marginal necrosis. The brown areas on the lower leaves enlarged rapidly and the margins became scorched. Elevation of K concentrations in the fertigation solution up to 8 mM increased the crop growth in leaf length, stem thickness, and fresh and dry matter production of above ground plant tissue. However, that decreased the chlorophyll contents. The 8.0 mM K treatment which showed the greatest growth had 5.01 g in dry weight and 2.76% in K content of above ground plant tissue, suggesting that maintaining K content higher than 1.7% is necessary for good growth of Perilla frutesens. The K concentrations in petiole sap and soil solution of 8.0 mM treatment were $12,289mg{\cdot}kg^{-1}\;and\;11.65mg{\cdot}L^{-1}$, respectively. These indicated that K fertilization to maintain higher than $8,700mg{\cdot}kg^{-1}$ in petiole sap and $4.5mg{\cdot}L^{-1}$ in soil solution are necessary to ensure good crop growth.

• Journal of Gastric Cancer
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• v.18 no.1
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• pp.69-81
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• 2018

Purpose: It has been reported that the survival of patients with locally advanced gastric cancer (LAGC) is better in East Asia countries than in developed western countries; however, the prognosis of LAGC remains poor. This study aimed to evaluate the effects of perioperative chemotherapy on the long-term survival of East Asia patients with LAGC. Materials and Methods: From October 2006 through August 2008, 43 patients with LAGC received perioperative S-1 combined with weekly docetaxel in a phase II study (neoadjuvant group). These patients were matched using propensity scores to patients who underwent surgery without neoadjuvant chemotherapy during the same period (surgery group). The surgical outcomes and long-term survivals were compared between the 2 groups. Results: After matching, 43 and 86 patients were included in the neoadjuvant and surgery groups, respectively, and there was no significant difference in their baseline characteristics. Although the operating time was longer in the neoadjuvant group, there was no significant difference in postoperative complications between the 2 groups. The neoadjuvant group had a significantly higher 5-year overall survival (OS) rate (73.3% vs. 51.1%, P=0.005) and a trend towards higher 5-year progression-free survival (PFS) (62.8% vs. 49.9%, P=0.145). In the multivariate analysis, perioperative chemotherapy was an independent factor for OS, with a hazard ratio of 0.4 (P=0.005) and a marginal effect on the PFS (P=0.054). Conclusions: Perioperative chemotherapy was associated with better long-term survival without increasing postoperative complications in the setting of D2 surgery for patients with LAGC, suggesting that perioperative chemotherapy can be a therapeutic option in East Asia countries.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.6
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• pp.861-867
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• 2008

The objective of this study was to evaluate the effect of exogenous ghrelin on the behaviors, weight gain, and feed intakes of weanling piglets. A total of 25 pairs of Duroc$\times$Landrace$\times$Large White piglets weaned at 21 days of age were used in this experiment which finished on day 36. Each pair of healthy piglets from the same litter with similar body weight and of the same gender were selected and randomly arranged to ghrelin or control groups. Thus, there were 50 piglets (ghrelin 25; control 25) kept in 10 pens (ghrelin 5; control 5) and 5 piglets per pen. Initial body weight of the pigs did not differ between the control and ghrelin treatment ($7.43{\pm}0.17kg$; p = 0.81). Experimental pigs were infused with ghrelin ($1{\mu}g/d$ pig) via the marginal ear vein between 0750 and 0800 h at 22, 23, 24 days of age. Control pigs were infused with 0.9% saline. Feed consumption was measured on days 23, 24, 25, 29 and 36. Body weight was measured on days 22, 23, 24, 25, 29 and 36. Behavior data of individual piglets were collected by real-time observation from 0800-1500 h through remote supervisory equipment at 22, 23 and 24 days of age. The results indicated that ghrelin infusion could increase drinking (p<0.05) and lying behaviors (p<0.01) and decrease mounting behaviors (p<0.05). No significant influence of ghrelin was found on average daily weight gain (ADG) and average daily feed intake (ADFI) in this experiment (p>0.05). In conclusion, exogenous ghrelin by the method above and at the dosage of $1{\mu}g/d$ pig could cause a variety of behavioral effects, but not improve performance of weanling piglets.

• Polymer(Korea)
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• v.30 no.1
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• pp.85-89
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• 2006

The effect of vapor grown carbon fiber (VGCF) contents on electrical and rheological properties of VGCF filled polyphenylene sulfide (PPS) composites prepared through melt mixing using a twin screw exruder was studied. This method was proved to be quite effective to produce good dispersion of VGCF in the matrix even for highly filled PPS. From the dependence of the electrical conductivity on VGCF content, the percolation phenomena began to occur above $10\;wt\%$. While there is only a marginal increase of viscosity for 1 and $5\;wt\%$ VGCF filled PPS, the composites containing $10\;wt\%$. While VGCF showed abrupt increase in viscosity as well as flattening of frequency vs modulus curve, indicating a transition from a liquid-like to a solid-like behavior due to the creation of VGCF network. This result agrees well to the fact that the network formation in the composite can be composite by rheological property dependence on filler content as well as by electrical conductivity measurement.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.502-514
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• 2002

The aim of this study was to evaluate the marginal adaptation of direct class II sandwich restoration with packable composites(P-60), resin modified glass ionomer cement(Fuji-II LC), flowable compomer(Dyract Flow), flowable composites(Filtek Flow) in comparison with total bond restorations. In addition, for sandwich restorations, influence of different sandwich techniques was also evaluated. Large butt-joint box typed class II cavites with cervical margins 1mm below the cemento-enamel junction were cut into 70 extracted human molars. The cavities(7 groups, n=10) were filled using a closed/open sandwich restoration or total bond restoration technique with materials according to the manufacturer's recommandation using the single-component bonding agent for each system. Teeth were thermocycled 500 times between 5$^{\circ}C$ and 55$^{\circ}C$ with 30-second dwell time. The teeth were then coated with nail polish 1mm short of the restoration, placed in a 2% methylene blue for 24 hours, and sectioned with diamond wheel. Sections were examined with a stereoscope to determine the extent of microleakage. Dentine /Cementum margins were analyzed for microleakage on scale of 0(no leakage) to 4(entire axial wall) and interface between materials, on scale of 0(no leakage) to 3(axial wall). Results were evaluated with Kruskal Wallis Test, corrected for ties, to determine whether there were statistically significant differences among the seven groups. Pairs of groups were analyzed using the Student-Newman-Keuls Method and Dunn s Method. The results were as follows : 1. All groups showed some micoleakage in cervical portion. But there were no microleakage in interface between materials. 2. Closed sandwich restorations with Fuji-II LC and Filtek Flow had significantly lower leakage rating than total restorations with only P-60. However, open sandwich restorations with Dyract Flow showed significantly higher (P<0.05) 3. Closed sandwich restorations had significantly lower leakage rating than total restorations. However open sandwich restoration s showed significantly higher (P<0.05). 4. Sandwich restorations with Fuji-II LC were iou$.$or leakage than only P-60. Filtek Flow, Dyract Flow. But there were no statistically differences among the materials. From the results above, it could be concluded, closed sandwich restorations was effective in reducing microleakage of class II restorations. The best results showing the least microleakage were for the closed sandwich technique with Fuji-II LC and Filtek Flow.

• Asia pacific journal of information systems
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• v.18 no.1
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• pp.117-144
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• 2008

Lots of virtual communities and online businesses presently derive their primary sources of revenues through advertising, but nevertheless are plagued with marginal profitability though they might possess a significant user base. In the light of the need for an efficacious business model, there have been recent insights of an online community in particular reaping profits through an innovative and lucrative revenue generation method that earns by selling digital items. There have been some obvious evidences (e.g., Cyworld, SecondLife, Habo Hotel, etc.) that online communities can be profitable through their unique business model of selling digital items. However, there is lack of understanding about the motivation of purchasing digital items. This study tries to identify the main motivators of digital item purchases based on social/individual identity theory and self-presentation theory. "Digital items", otherwise known as "virtual assets", may include online avatars, accessories for the avatars, decorative ornaments like furniture, digital wallpapers, skins, background music and virtual weapons used for Internet games. These digital items are employed by users for representation and articulation in the online space, especially to create and enhance their online profiles in web pages and games. Prices for digital items typically range from a few cents to a few dollars each. Based on the theoretical framework like social identity theory and self-presentation theory, we developed the research model and proposed seven hypotheses. An analysis of 225 members of Cyworld found that digital item purchase intention in virtual world is affected by both members' need for self-presentation and need for affiliation. We also found that the need for self-presentation is significantly increased by innovativeness of members, community group norm, and community involvement. We concluded that the need for self-presentation could be a key variable for profitable business model in online community service industry. However, neither individual self-efficacy nor the need for affiliation significantly influenced the need for self-presentation which triggers purchase intention of digital items. In term of the theoretical and practical contribution, this study can be a pioneering empirical research that investigates the purchase intention of digital items based on social identity theory and self-presentation theory in the online context. Also, the findings of our study are valuable and practical for practitioners in the market who wish to adopt or improve the business model of selling digital items in an online community. From the findings, it can be seen that innovativeness of users, community group norm, and community involvement are three significant factors that influence need for self-presentation of users which ultimately leads to their intentions to buy digital items. These findings put forth that virtual community providers and online businesses selling digital items should prioritize their efforts and focus on these three factors if they want to increase the sales of these digital items and generate greater revenues. This study provides important implications for academic researchers and practitioners to understand why the community members pay money for their digital items in virtual world and how the practitioners can increase the sales of digital items in an online community. A couple of limitations of the study and future research directions are also discussed.