• Journal of Periodontal and Implant Science
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• v.50 no.5
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• pp.327-339
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• 2020

Purpose: The purpose of this study was to examine the local tissue reactions associated with 3 different poly(lactic-co-glycolic acid) (PLGA) prototype membranes and to compare them to the reactions associated with commercially available resorbable membranes in rats. Methods: Seven different membranes-3 synthetic PLGA prototypes (T1, T2, and T3) and 4 commercially available membranes (a PLGA membrane, a poly[lactic acid] membrane, a native collagen membrane, and a cross-linked collagen membrane)-were randomly inserted into 6 unconnected subcutaneous pouches in the backs of 42 rats. The animals were sacrificed at 4, 13, and 26 weeks. Descriptive histologic and histomorphometric assessments were performed to evaluate membrane degradation, visibility, tissue integration, tissue ingrowth, neovascularization, encapsulation, and inflammation. Means and standard deviations were calculated. Results: The histological analysis revealed complete integration and tissue ingrowth of PLGA prototype T1 at 26 weeks. In contrast, the T2 and T3 prototypes displayed slight to moderate integration and tissue ingrowth regardless of time point. The degradation patterns of the 3 synthetic prototypes were similar at 4 and 13 weeks, but differed at 26 weeks. T1 showed marked degradation at 26 weeks, whereas T2 and T3 displayed moderate degradation. Inflammatory cells were present in all 3 prototype membranes at all time points, and these membranes did not meaningfully differ from commercially available membranes with regard to the extent of inflammatory cell infiltration. Conclusions: The 3 PLGA prototypes, particularly T1, induced favorable tissue integration, exhibited a similar degradation rate to native collagen membranes, and elicited a similar inflammatory response to commercially available non-cross-linked resorbable membranes. The intensity of inflammation associated with degradable dental membranes appears to relate to their degradation kinetics, irrespective of their material composition.

• The Journal of Korean Physical Therapy
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• v.21 no.3
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• pp.1-8
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• 2009

Purpose: The purpose of this study was to examine the functional category, the item structure and the model-data fit of the neck disability index (NDI) of neck pain subjects by performing a Rasch rating scale analysis. Methods: The data was obtained from the assessments of 71 college students (males: 27, females: 44) with neck pain. The data of the NDI was applied to the Rasch's rating scale model to estimate the difficulty of items, the goodness-of-fit of each item, the separation reliability and index, and the rating scale. Results: The 'sleep' item showed misfit and nine items were founds to be fits for self-reporting of disability due to neck pain. The most difficult item of the remaining 9 items was 'work' and the easiest item was 'headache'. The transformation formula score=(logit score+7.10)/(7.10+0.11)$\times$100. The 6 response levels of the NDI were validated according to the structure of the rating scale. The item and subject reliability of the separation reliability was 0.97 and 0.85, respectively. Conclusion: We proved that the NDI for self-reporting of disability of daily activities due to mild neck pain was valid and reliable. This study suggests that individuals with mild neck pain may be assessed by using the modified NDI that does not include the 'sleep' item in the 10 items of NDI.

• International Journal of Concrete Structures and Materials
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• v.9 no.1
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• pp.89-118
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• 2015

The geometric nonlinearity of off-diagonal bracing system (ODBS) could be a complementary system to covering and extending the nonlinearity of reinforced concrete material. Finite element modeling is performed for flexural frame, x-braced frame and the ODBS braced frame system at the initial phase. Then the different models are investigated along various analyses. According to the experimental results of flexural and x-braced frame, the verification is done. Analytical assessments are performed in according to three dimensional finite element modeling. Nonlinear static analysis is considered to obtain performance level and seismic behaviour, and then the response modification factors calculated from each model's pushover curve. In the next phase, the evaluation of cracks observed in the finite element models, especially for RC members of all three systems is performed. The finite element assessment is performed on engendered cracks in ODBS braced frame for various time steps. The nonlinear dynamic time history analysis accomplished in different stories models for three records of Elcentro, Naghan and Tabas earthquake accelerograms. Dynamic analysis is performed after scaling accelerogram on each type of flexural frame, x-braced frame and ODBS braced frame one by one. The base-point on RC frame is considered to investigate proportional displacement under each record. Hysteresis curves are assessed along continuing this study. The equivalent viscous damping for ODBS system is estimated in according to references. Results in each section show the ODBS system has an acceptable seismic behaviour and their conclusions have been converged when the ODBS system is utilized in reinforced concrete frame.

• Journal of the Korean Institute of Gas
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• v.18 no.2
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• pp.55-61
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• 2014

In this study, we evaluated the measurement of working environment, the amount of exposure, the hazards and risks of biphenyl, that was registered as 2A in IARC. Based on the exposure scenario, it was calculated that the exposure amounts are $1.0{\times}10^{-2}$, $4.2{\times}10^{-4}$, $7.0{\times}10^{-6}mg/m^3$, respectively, and the $RfC_{work}$ is 0.21, 2.13, 0.53 $0.31mg/m^3$ as carcinogenicity, target toxicity (oral), target toxicity (inhalation), developmental toxicity, respectively. According to these hazards evaluation and risk assessments, it was estimated that 0.57, 0.39 as carcinogenicity and non-carcinogenicity (developmental toxicity), respectively. It was also estimated relatively lower risks below 1. But since biphenyl is hazardous used much amounts, and could be exposed to workers directly, it was determined to require exposure monitoring to protect workers' health.

• Journal of Korea Water Resources Association
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• v.41 no.9
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• pp.907-917
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• 2008

This study investigates differences in hydrological responses to the climatic scenarios resulting from the use of different three hydrological models, PRMS, SLURP, and SWAT. First, the capability of the three models in simulating the present climate water balance components is evaluated at Andong-dam watershed. And then, the results of the models in simulating the impact using hypothetical climate change scenarios are analyzed and compared. The results show that three models have similar capabilities in simulating observed data. However, greater differences in the model results occur when the models are used to simulate the hydrological impact under hypothetical climate change. According as temperature change grows, the differences between model results is increasing because of differences of the evapotranspiration estimation methods. The results suggest that technique that consider the uncertainty by using different hydrological models will be needed when climate change impact assessment on water resources.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.2
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• pp.74-82
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• 2010

As the basic knowledge during designing most moving mechanical structures, vibration engineering is a subject teaching the theory on vibration control and isolation, which also cultivating the ability of analyze variety of vibration problems. However, vibration engineering is more difficult to understand than other dynamics courses in mechanical field, so the development of educational equipments in order to help understanding physical theory of vibration is really necessary. So in this paper we could see the effect after doing simple experiment process using the educational vibration equipment with multiple function, students could easily understand physical theory of vibration. The educational vibration equipment with multiple function and its application range are introduced, which could performance four kinds of typical vibration phenomenon: vibration of multidegree of freedom system, vibration of beam, vibration of beam, and vibration of plate. Finally, assessments of response and improvement plan are proposed through a survey.

• Archives of Plastic Surgery
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• v.36 no.1
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• pp.38-45
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• 2009

Purpose: The congenital muscular torticollis is a neck deformity involving shortening of the sternocleidomastoid muscle, which is detected at birth or shortly after birth. This childhood disease is the third most common congenital musculoskeletal anomaly. The indication for surgery is a persistent head tilt with dificit of passive rotation and lateral bending of the neck and a tight band or tumor in the sternocleidomastoid muscle even after physical therapy. The purpose of this article is to report surgical outcomes with patients who had no or little response to physical therapy. Methods: Surgery was performed on 29 patients and their average age was 4.1 years (from 6 months to 20.1 years). The unipolar open release and partial myectomy were done in 28 cases and the muscle lengthening was done in 1 case. Physical therapy was started from postoperative seventh day. Follow - up period was ranged from 2 months to 5.4 years(mean follow - up, 20.4 months). Result: There were neither rotation nor lateral bending deficit after surgical treatment. Mild head tilt was noticed in 3 cases and residual bend was observed in 4 cases. The subjective assessments of surgical results by parents were excellent. Conclusion: Our surgical outcome encourages the surgical treatment of congenital muscular torticollis for patients who failed to respond to physical therapy.

• Earthquakes and Structures
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• v.18 no.2
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• pp.147-162
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• 2020

This paper presents a novel precast energy dissipation shear wall (PEDSW) structure system that using mild steel dampers as dry connectors at the vertical joints to connect adjacent wall panels. Analytical studies are systematically conducted to investigate the seismic performance of the proposed PEDSW under sequence-type ground motions. During earthquake events, earthquake sequences have the potential to cause severe damage to structures and threaten life safety. To date, the damage probability of engineering structures under earthquake sequence has not been included in structural design codes. In this study, numerical simulations on single-story PEDSW are carried out to validate the feasibility and reliability of using mild steel dampers to connect the precast shear walls. The seismic responses of the PEDSW and cast-in-place shear wall (CIPSW) are comparatively studied based on nonlinear time-history analyses, and the effectiveness of the proposed high-rise PEDSW is demonstrated. Next, the foreshock-mainshock-aftershock type earthquake sequences are constructed, and the seismic response and fragility curves of the PEDSW under single mainshock and earthquake sequences are analyzed and compared. Finally, the fragility analysis of PEDSW structure under earthquake sequences is performed. The influences of scaling factor of the aftershocks (foreshocks) to the mainshocks on the fragility of the PEDSW structure under different damage states are investigated. The numerical results reveal that neglecting the effect of earthquake sequence can lead to underestimated seismic responses and fragilities, which may result in unsafe design schemes of PEDSW structures.

• Environmental and Resource Economics Review
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• v.16 no.3
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• pp.653-682
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• 2007

In this study, multi-sectoral partial equilibrium and computable general equilibrium models of Taiwan are used to investigate the direct and indirect effects of energy price increases on overall economies and agro-food sector in Taiwan. The results suggest that agricultural prices, production cost would increase between 0.27% to 1.88%, and a reduction in GDP around 0.39% to 0.54 %. The negative impact on livestock sector is slightly higher than that on the crop sector. Negative impacts are also observed in the employment and wages. The rising oil price has the potential to discourage production of energy-intensive activity because of the possibility of substitution and adaptations. The growth rate of real GDP will shrink by 0.64% to 1.06% and CPI will increase by 1.17% to 1,95%. Both the agriculture and non-agricultural sector also respond by raising output prices by 0.80% to 1.33%. The rising international oil price has urged the government to take policy actions like using alternative fuels such as biodiesel, bioethanol, and adopting measures to cut down on energy consumptions mainly in transportation sectors in response to public concern over economic shocks.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.31-37
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• 2009

Most damages of civil infrastructures under natural disasters are frequently occurred at surrounding areas of the river or the road. Every year, Recovery for these disaster damages are performed by the government. Recently, the government decide to change current recovery plan system because current recovery plan which doesn't consider future disaster impacts at a site has been proved to be ineffective. Accordingly, new permanency recovery plan system is needed and its corresponding ideas are presented in this research considering more detailed disaster damage classifications and cause assessments. The proposed permanency recovery plan would also provide more systematic and diverse recovery response strategies including both two concepts, for example Preparedness considered by risk assessment and management, and Mitigation investigated by hazard impact analyses.