• Structural Engineering and Mechanics
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• 제8권6호
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• pp.531-546
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• 1999

The paper presents an experimental and theoretical study on the influence of steel fibers and longitudinal tension and compression reinforcements on immediate and long-term deflections of high-strength concrete beams of 85 MPa (12,300 psi) compressive, strength. Test results of eighteen beams subjected to sustained load for 180 days show that the deflection behavior depends on the longitudinal tension and compression reinforcement ratios and fiber content; excessive amount of compression reinforcement and fibers may have an unfavorable effect on the long-term deflections. The beams having the ACI Code's minimum longitudinal tension reinforcement showed much higher time-dependent deflection to immediate deflection ratio, when compared with that of the beams having about 50 percent of the balanced tension reinforcement. The results of theoretical analysis of tested beams and those of a parametric study show that the influence of steel fibers in increasing the moment of inertia of cracked transformed sections is most pronounced in beams having small amount of longitudinal tension reinforcement.

• 대한한의학회지
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• 제18권1호
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• pp.218-237
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• 1997

In order to investigate the antihypertentive effects and its mechanism of the Siegesbeckia pubescens aqua-acupuncture treatment, experiments were performed on immediate and continuous antihypertensive effects, vasodilatation-autonomic nerve block, diuretic activity, and angiotensin converting enzyme inhibitory activity. The results were as follows; 1. Acupuncture treatment group showed significantly immediate antihypertensive effects in 4 hours after treatment. Normal saline aqua-acupuncture treatment group showed significantly immediate antihypertensive effects in 2, 4 and 6 hours after treatment. Siegesbeckia pubescens aqua-acupuncture treatment group showed significantly immediate antihypertensive effects in 30 minutes, 1, 2, 4 and 6 hours after treatment. 2. Siegesbeckia pubescens aqua-acupuncture treatment group showed significantly continuous antihypertensive effects in 6, 8, 9 and 10 days after treatment. 3. Siegesbeckia pubescens aqua-acupuncture extract solution showed significantly vasodilatatory and sympathetic nerve block effects with concentration of $10^{-6},\;10^{-5},\;10^{-4},\;10^{-3}g/m{\ell}$. 4. Oral administration group of the Siegesbeckia pubescens aqua-acupuncture extract solution didn't show no significantly diuretic effects. 5. Siegesbeckia pubescens aqua-acupuncture extract solution showed 28.8% angiotensin converting enzyme inhibitory activity.

• Journal of Periodontal and Implant Science
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• 제38권2호
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• pp.253-262
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• 2008

Background: Incomplete flap coverage or early exposure over implants and/or barrier membranes have a negative effect on bone regeneration. In cases of using regenerative techniques, complete soft tissue coverage of the implant area is necessary to promote adequate conditions for guided bone regeneration. Primary socket closure may be difficult, when periosteal releasing incision is only used, due to the opening left by extracted tooth. Therefore, Soft tissue grafting techniques are used to achieve primary soft tissue closure. Materials and Methods: Soft tissue grafting techniques, with or without barrier membranes, were performed for primary closure in four cases of immediate placements. Three different methods were used (CTG, VIP-CT, Palatal advanced flap). Clinical results of the grafting were evaluated. Result: One case showed early exposure of cover-screw and, no other complications were noted. In the others, Primary closure was achieved by soft tissue grafting techniques. One of the cases, Graft showed partial necrosis, but there were no exposure over implants and/or barrier membranes. Conclusion: The use of grafting techniques, in immediate implant placement, can predictably obtain primary closure of extraction sockets, thereby providing predictable bone formation and improved implant results.

• 한국간호교육학회지
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• 제21권3호
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• pp.350-360
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• 2015

Purpose: The purpose of this study was to evaluate the effectiveness and retention period of immediate remediation for infant cardiopulmonary resuscitation (CPR) in child care teachers. Methods: This study used a nonequivalent comparison pre- and post-test design to measure knowledge about and confidence in infant CPR and an interrupted time-series design to determine skill performance. The experimental group (n=25) received both immediate remediation and video learning for infant CPR, and the comparison group (n=28) received video learning only. Knowledge and confidence were measured before and after 4 weeks. Their skill performance was tested immediately, and 4 weeks, 8 weeks, 12 weeks, and 24 weeks after intervention. Data analysis consisted of ${\chi}^2$ tests, t-tests, paired t-tests, and a generalized linear mixed model. Results: There were significant increases in knowledge and confidence within the experimental group. Skill performance showed a significant difference according to the group factor (F=10.81, p=.002) and measurement time (F=146.80, p<.001). The experimental group maintained significantly higher skill performance than did the comparison group. Conclusion: These findings support the necessity of immediate remediation education for infant CPR to maintain skill performance. In addition, appropriate renewal time and the improvement of training programs for child care teachers are necessary.

• 아태비즈니스연구
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• 제14권1호
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• pp.215-229
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• 2023

Purpose - Based on the funding-horizon theory, this study aims to test the effects of cash needs and the persistence of external funding needs on firms' external financing. Design/methodology/approach - Financial data of Korean listed companies were collected from DataGuide. Immediate and near-term cash shortfalls are defined using the methodology of Haung and Ritter (2021). We estimate multinomial logit regressions for the financing choice. Findings - First, all three cash depletion variables used in our study increase the likelihood of external financing. Second, firms prefer to issue debt to meet immediate spending and equity to meet long-lived cash needs. Third, this effect is more pronounced for high R&D firms. Fourth, chaebol firms with internal capital markets defer raising external capital for immediate and near-term cash needs. Research implications or Originality - This paper provide empirical evidence that immediate and near-term cash needs induce external financing, and the persistence of cash needs affects the choice between debt and equity, the finding which is consistent with the funding-horizon theory of financing decisions. Being the first paper to test the funding-horizon theory using Korean data, this paper contributes to the literature on the capital structure of Korean firms.

• Restorative Dentistry and Endodontics
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• 제42권3호
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• pp.188-199
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• 2017

Objectives: This in vitro study evaluated the effect of dentin biomodifiers on the immediate and long-term bond strengths of a simplified etch and rinse adhesive to dentin. Materials and Methods: Flat coronal dentin surfaces were prepared in 120 extracted human molars. Teeth were randomly divided into 5 groups (n = 24) according to 5 different surface pre-treatments: No pre-treatment (control); 1M carbodiimide (EDC); 0.1% epigallocatechin-3-gallate (EGCG); 2% minocycline (MI); 10% sodium ascorbate (SA). After surface pre-treatment, adhesive (Adper Single Bond 2 [SB], 3M ESPE) was applied. Composite was applied into transparent plastic tubes (2.5 mm in diameter), which was placed over the bonded dentin surface. From each group, 10 samples were subjected to shear bond strength (SBS) evaluation at 24 hours (immediate) and remaining 10 samples were tested after 6 months (delayed). Additionally, 4 samples per group were subjected to scanning electron microscopic analysis for observation of resin-dentin interface. The data were statistically analysed with Shaperio-Wilk W test, 2-way analysis of variance (ANOVA), and post hoc Tukey's test. Results: At 24 hours, SBS of all surface pre-treatment groups were comparable with the control group, with significant differences found between EDC and SA groups only (p = 0.009). After 6 months storage, EDC, EGCG, and MI pre-treatments preserved the resindentin bond strength with no significant fall. Conclusions: Dentin pre-treatment with all the dentin biomodifiers except SA resulted in significant preservation of resin-dentin bond over 6 months storage period, without negatively affecting the immediate bond strength of the etch and rinse adhesive tested.

• 한국정보시스템학회지:정보시스템연구
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• 제28권4호
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• pp.251-270
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• 2019

Purpose Unlike advertising through the traditional media targeting unspecified number of people, the base of mobile environment using smartphone has expanded so that many companies can classify prospective customers according to their purpose, thereby enabling efficient targeted marketing with low cost. Design/methodology/approach This study has investigated how can marketing strategy be influenced by the price promotion type (immediate discount/delayed discount) and message framing (positive/negative) according to time pressure (low/high). Hypotheses are set through the consideration of prospect theory, endowment effect, framing effect, regulatory-focus theory, and time-pressure theory. Findings The results and interpretation of this study are as follows. First, it was found that the influence of the delayed discount on the purchase intention was larger than the immediate discount. Second, negative/loss frame messages have more influence on purchase intention than positive/profit frame messages. Third, when the price promotion type is delayed discount, the effect of the promotion message on the purchase intention when it presented by negative/loss frame is greater than the other cases. The implication of this study is that it can be used as a basic data for establishing a strategy to maximize the effectiveness of promotions effectively considering potential buyers of mobile commerce environment.

• 대한치과교정학회지
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• 제38권3호
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• pp.149-158
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• 2008

본 연구는 미니 임플란트 식립 후 교정력 부하시기와 관련하여 임플란트 주위골의 치유과정을 조사하였다. 성견 8마리의 하악 협측골에 교정용 미니 임플란트(ORLUS, Ortholution CO, Korea) 48개를 식립한 후 교정력을 주지 않은 대조군과 식립 후 즉시 교정력을 준 즉시 부하군, 그리고 식립 후 3주간의 치유기간을 두고 교정력을 준 지연 부하군으로 나누어 각각의 군에 대해 3주, 6주, 12주가 경과된 시점에 임플란트 주위골의 변화를 조직 계측학적으로 관찰하였다. 골 접촉률은 즉시 부하군에서 시기에 따른 유의한 변화가 없었으며 지연 부하군은 3주에 비해 12주에서 유의하게 증가하였다(p<0.05). 각 시점에서 군간의 골 접촉률을 비교했을 때 12주째 지연 부하군이 즉시 부하군 보다 유의하게 높았다(p<0.05). 골 면적비율은 즉시 부하군의 경우, 시기에 따른 유의한 변화가 없었으며, 지연 부하군과 대조군은 6주에 비해 12주째 유의한 증가를 보였으며 (p<0.05), 12주째 실험군 간에 유의한 차이는 관찰되지 않았다(p>0.05). 동요도는 12주째 즉시 부하군과 지연 부하군 간에 유의한 차이는 없었다(p>0.05). 위의 결과에서 즉시 부하가 self drilling형 미니 임플란트 주위골의 안정성에 부정적인 영향을 주지 않았으므로 식립 즉시 교정력을 부여하여 사용하는 데 임상적으로 문제가 없을 것으로 판단된다.

• 구강회복응용과학지
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• 제25권3호
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• pp.255-265
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• 2009

즉시 하중에 대한 관심과 시도가 증가되고 있지만, 명확한 술식이 정립되어 있지는 않다. 본 연구에서는 상악 전치부 임플란트에서 즉시 하중시에 골과 임플란트에 나타나는 응력분포 양상을 3차원 유한요소법을 이용하여 알아보고자 하였다. 골질이 D3인 상악 전치부의 골모형을 구성하고, 서로 다른 길이(8.5 mm, 10.0 mm, 11.5 mm, 13.0 mm, 15.0 mm)의 직경 4.0 mm 나사형 임플란트를 식립한 모형을 제작하였다. 해석 절차의 간소화를 위하여 모든 물성은 등방성, 선형탄성, 균질성으로 가정하였다. 골-임플란트 계면은 접촉 요소법으로 처리하여 골유착이 일어나기 전 상태로 구성하였다. 지대주 장축에 120도의 각도로 지대주의 구개 절단각 중앙부에 176 N의 정하중을 가하고 응력분포를 관찰하였다. von Mises stress를 이용하여 응력을 분석한 결과 모든 모형에서 순측 피질골에 응력이 집중되었으며 피질골과 망상골의 경계부에서 최대 응력값을 나타내었다. 길이에 따른 비교시 8.5 mm 모형에서 가장 큰 최대 응력값을 나타냈으며, 임플란트 길이가 증가될수록 좀 더 양호한 응력 분포를 나타내었다. 상악 전치부 즉시 하중시에 피질골의 존재 유무는 매우 중요하며, 길이가 긴 임플란트를 식립하는 것이 유리하며, 가능하면 13.0 mm 이상의 임플란트를 식립하는 것이 즉시하중을 시행할 때 응력 분산에 유리한 것으로 판단된다.

• The Journal of Advanced Prosthodontics
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• 제2권2호
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• pp.39-45
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• 2010

PURPOSE. The aim of this study was to determine differences in shear bond strength to human dentin using immediate dentin sealing (IDS) technique compared to delayed dentin sealing (DDS). MATERIALS AND METHODS. Forty extracted human molars were divided into 4 groups with 10 teeth each. The control group was light-cured after application of dentin bonding agent ($Excite^{(R)}$ DSC) and cemented with $Variolink^{(R)}$. II resin cement. IDS/SE (immediate dentin sealing, $Clearfil^{TM}$ SE Bond) and IDS/SB (immediate dentin sealing, $Adapter^{TM}$ Single Bond 2) were light-cured after application of dentin bonding agent ($Clearfil^{TM}$ SE Bond and $Adapter^{TM}$ Sing Bond 2, respectively), whereas DDS specimens were not treated with any dentin bonding agent. Specimens were cemented with $Variolink^{(R)}$. II resin cement. Dentin bonding agent ($Excite^{(R)}$. DSC) was left unpolymerized until the application of porcelain restoration. Shear strength was measured using a universal testing machine at a speed of 5 mm/min and evaluated of fracture using an optical microscope. RESULTS. The mean shear bond strengths of control group and IDS/SE group were not statistically different from another at 14.86 and 11.18 MPa. Bond strength of IDS/SE group had a significantly higher mean than DDS group (3.14 MPa) (P < .05). There were no significance in the mean shear bond strength between IDS/SB (4.11 MPa) and DDS group. Evaluation of failure patterns indicates that most failures in the control group and IDS/SE groups were mixed, whereas failures in the DDS were interfacial. CONCLUSION. When preparing teeth for indirect ceramic restoration, IDS with $Clearfil^{TM}$ SE Bond results in improved shear bond strength compared with DDS.