The purpose of this study was to evaluate the bioflavonoids naringin on dental caries and periondontal disease in the albinorat. Twenty-five-day-old-male rats were fed the experimental diets for 42 days in this work at the end of the 42-day experimental period. The tooth surfaces were examined under a dissecting microscope. The sulcular caries lesions were recorded : the first molars were more affected than the second and third molars. Alveolar bone loss was measured on the buccal and lingual aspects of each molar: three site measurements (mesialpoint midpoint and distalpoint) were taken on the first molars. The results showed that the bioflavonoids, naringin had beneficial effects in the prevention of periodontal disease.

This study analyzed future projections on daily mean values and extremes for temperature and daily precipitation over Seoul metropolitan city using bias-corrected high-resolution multi-regional climate models. The factors of uncertainty for the future projection of climate variables were defined. In the time series analysis of future projections for regional climate models, the average daily temperature and the number of days of the hot day-hot night were predicted to have a stable trend in the RCP2.6 scenario, and showed a tendency to increase continuously in the RCP8.5 scenario. The daily mean precipitation and RX1day (annual daily maximum precipitation) had large annual variabilities in the models. In the estimation of the fraction of total variance, the daily mean temperature was dominated by the internal variability in the early 21st century and the most contributing to the scenario uncertainty in the late 21st century. The daily mean precipitation showed a remarkable contribution from the internal variability over the entire period. The number of days of the hot day-hot night showed a similar contribution pattern to that of the daily mean temperature. For the RX1day, the internal variability dominated over the entire period, and the scenario uncertainty had little contribution. This study will help establish more scientific climate change adaptation policies by providing the uncertainty information for future climate change projection.

The long-term variability of summer heavy rainfall in the Seoul metropolitan area was investigated in this study for the period of 1970-2018. The study period was divided into two phases; first phase from 1970 to 1994 and the second phase was 1995 to 2018. Long-term variability of summer heavy rainfall was examined using the change-point analysis method. Annual mean heavy rainfall amounts showed increasing trends in Seoul and Incheon during summer monsoon season (June to August). Results revealed that the changes in frequency and amount of heavy rainfall were observed larger in the months of July and August as compare to June during the second phase. The upper-level trough was prominently developed at the west of the Seoul metropolitan area and the core region of the upper-level jet was shifted to the east of the area during second phase. The western North Pacific subtropical high was expanded westward and moisture flux flowed along the southwesterly wind, resultant increasing moisture supply. The temperature and humidity tended to increase recently at the lower and mid-levels.

In this study, uncertainty ranges for bias-corrected temperature and precipitation in seven metro-cities were estimated using nine GCM-RCM Matrix, and climate changes were predicted based on the corrected temperature and precipitation. During the present climate (1981-2005), both uncertainties for annual temperature and precipitation and differences in regional uncertainties were reduced by bias correction methods. Model’s systematic errors such as cold bias of surface air temperature and underestimated precipitation during the second-Changma period were improved by a bias correction method. Uncertainties of annual variations for bias corrected temperature and precipitation were also decrease. Furthermore, not only mean values but also extreme values were improved by bias correction methods. During the future climate (2021-2050), differences in temperature and precipitation between two RCP scenarios (RCP4.5/8.5) were not quite large. Temperature had an obvious increasing tendency, while future precipitation did not change significantly compared to present one in terms of mean values. Uncertainties for future biascorrected temperature and precipitation were also reduced. In mid-21st centuries, models prospected that mean temperature increased thus lower extremes associated with cold wave decreased and upper extremes associated with heat wave increased. Models also predicted that variations of future precipitation increased thus the frequency and intensity of extreme precipitation increased.

This paper presents a methodology for assessing the old-age level of facilities. In order to evaluate the retirement level, a method of selecting the indicators related to the old age was presented and a method of assessing the old age level through the measures of the selected indicators is suggested to improve the reliability of evaluation results and to develop evaluation algorithm. In the future, it is expected that it will be possible to efficiently manage the old facilities through the convergence of the old- level evaluation method and IoT sensor, big data, and artificial intelligence.

In case of cable supported bridges, the cable system is a very important element that transfers the load of the girder to the pylon or substructure is the most important feature. The safety management of these cable systems is very important because they are directly linked to the safety of the entire bridge. This paper presents the applicability of the acoustic emission (AE) method is one of the non-destructive evaluation methods, is evaluated for the detection and monitoring of bridge cable damage. In order to verify the performance of the cable inspection method using the AE sensor, experiments were conducted. As a result, it is considered that the acoustic emission technique will be able to detect corrosion breakage and signs of rupture of cables if sufficient database of AE signal with various environmental conditions is secured.

본 연구에서는 음향 방출 기법을 사용하여 강연선(7-wire strand)의 손상을 감지하기 위한 기초 실험을 수행하였다. 강연선은 주로 교량에 추가적인 인장력을 제공하기 위해 널리 사용되는 건설 자재이다. 프리스트레스 교량 또는 사장교가 대표적인 경우이다. 그러나 교량 노화가 급격히 진행되면서 강연선 부식 문제가 대두되고 있다. 이러한 이유로 케이블 점검을 위한 다양한 비파괴 방법이 연구되고 있고 현장 적용 이 시도되고 있다. 비파괴 방법 ??중 하나인 음향 방출 기법은 케이블 손상 및 파단을 감지하는 효과적인 기술로 알려져 있다. 본 연구에서는 음향 방출 기법의 교량에 대한 적용 가능성을 평가하기 위해 강연선의 손상에 따른 음향 방출 신호 특성을 인장 실험을 분석 하고, 현장 적용을 위한 최적 센서 주파수 타입을 선정하였다. 결과적으로, 음향 방출 기법을 활용하여 향후 교량 케이블의 부식 파단 및 파단 징후를 감지 할 수 있다 고 여겨진다.

In this study, the durability rating was evaluated to evaluate the safety of bridges considering the factors affecting the corrosion of cables in cable-stayed bridges and suspension bridges. Corrosion factors were considered for salinity, sulfur dioxide concentration and relative humidity. In addition, the durability level was calculated by applying the corrosion rates given in KS D ISO 9223 ~ 9226.

The corrosion is one of the main causes of cable damages. The use of dehumidification system can be an alternative for this issue. Therefore, the authors have been evaluated for efficiency of the cable dehumidification system for the main cables of a suspension bridge. This study was initiated to develop an efficient and economical management strategy to operate the cable dehumidification system for suspension bridges built in the coastal region of South Korea.

This study presents the investigation for relationship between local damage and structural performance of the 7-wire strand. This strand is often used additional reinforcement of bridges such as PSC (Prestressed Concrete) bridge and cable-stayed bridge. Stay cables are continuously damaged after completion and corrosion is the main cause of damage. Due to its structural characteristics, it is difficult to quantitatively evaluate the degradation cable damage. Therefore the relationship between local damages on strand and structural performance is experimentally and analytically evaluated in this study. The results can be used for the safety management of the cable supported bridges in the future.

This paper presents the assessment of 7-wire strand monitoring using acoustic emission technique for bridges. 7-wire strand is widely used construction materials to provide additional tensile force to bridges. PSC (PreStressed Concrete) bridge and cable-stayed bridge are representatives for such cases. However, as the bridge aging progresses recently, corrosion problems of strand are emerging. For this reason, various NDT (Non-Destructive Test) methods for cable inspection are being studied and applied to the field. One of the NDT methods, acoustic emission technique, is known as an effective technique to detect cable damage and breakage. In this study, to evaluate the applicability of acoustic emission technique to bridges, acoustic emission signals according to presence or absence of the strand were acquired and analyzed by tensile test. As a result, it is considered that the acoustic emission technique will be able to detect corrosion breakage and signs of rupture.

This paper aims to evaluate the safety of the cable supported bridges under the occurrence of damages on cable system. There are more than 50 cable supported bridges currently built in the Korean peninsula and efficient and systematic maintenance and management are in great demand. However, safety of the bridges cannot be under estimated and should be properly evaluated. In this paper, two bridges (one cable-stayed bridge and one suspension bridge) in South Korea were investigated their safety based on the damage scenario of cable system. FEM analysis for safety evaluation of the two bridges was conducted and the results were explained. The result could be used by operators and owners of bridges for the future maintenance and management.

For suspension bridges, the super-structure is supported by main cables and hangers which carry the dead and live loads to the pylons and anchorages. Due to the fact that the difficultly of repair and strengthening for damaged cables, it is very important to find an efficient way of maintenance methods for cables. The corrosion is one of main causes for cable damages. The use of dehumidification system can be an alternative for this issue. Therefore, the authors have been evaluated for efficiency of the cable dehumidification system for main cables of suspension bridge. This study was initiated to develop an efficient and economical management strategy to operate the cable dehumidification system for suspension bridges built in South Korea.

This study aims to establish design and construction procedure in the fields of the repair and rehabilitation for existing concrete structures. The codes used in this study are ISO 16311 and ACI 562-16. The ISO 16311 and ACI 562-16 focused on maintenance and repair, respectively. After, we will make to design and construction guidelines to meet the domestic situation through analysis the repair and rehabilitation parts of the codes in detail.

Regional climate simulations for the CORDEX East Asia domain were conducted between 1981 and 2100 using five models to project future climate change based on RCP2.6, 4.5, 6.0, and 8.5 scenarios. By using the ensemble mean of five model results, future changes in climate zones and four extreme temperature events of South Korea were investigated according to Köppen-Trewartha’s classification criteria. The four temporal periods of historical (1981-2005), early future (2021-2040), middle future (2041-2070), and late future (2071-2100) were defined to examine future changes. The analysis domain was divided into 230 administrative districts of South Korea. In historical (1981-2005) period, the subtropical zones are only dominant in the southern coastal regions and Jeju island, while those tend to expand in the future periods. Depending on the RCP scenarios, the more radiative forcing results in the larger subtropical zone over South Korea in the future. The expansion of the subtropical zone in metropolitan areas is more evident than that in rural areas. In addition, the enlargement of the subtropical zone in coastal regions is more prominent than that of in inland regions. Particularly, the subtropical climate zone for the late future period of RCP8.5 scenario is significantly dominant in most South Korea. All scenarios show that cold related extreme temperature events are expected to decrease and hot related extreme temperature events to increase in late future. This study can be utilized by administrative districts for the strategic plan of responses to future climate change.

In this study, it was modelled high-rise building applying outrigger damper system and analyzed by applying eccentric load. By controlling the variation of damping and stiffness of the damper, the seismic response control performance of outrigger damper system was analysed. An outrigger damper system is effective in controlling the top floor displacement response and torsional angle. Therefore, the damper should be selected the proper stiffness value because the variation of stiffness have an influence on the torsional angle.

Acinetobacter baumannii is one of the most problematic causative agents of nosocomial infections, especially in the immune compromised or patients in intensive care units. In recent years, as multiple antibiotic resistant A. baumannii has increasingly emerged, it has become difficult to treat infections effectively. The authors report a case of extreme drug resistant A. baumannii bacteremia caused by catheter-related infection, as confirmed by blood and catheter tip culture, in a 63-year-old man. The patient responded well to 24 days of doripenem and colistin treatment.

In this study, global climate change scenario by Hadley Centre Global Environmental Model version 2-Atmosphere and Ocean (HadGEM2-AO) is dynamically downscaled using four regional climate models (RCMs). All RCMs with 12.5-km and 50-km resolution are integrated for continuous 27 years (1979-2005). In general, RCMs with higher horizontal resolution more reasonably capture the spatial distribution of precipitation over South Korea compared to those with lower resolution. In particular, heavy precipitation regions related to complex mountain ranges are well simulated due to detailed topography in RCMs with higher resolution. Difference between RCMs with dissimilar resolutions is relatively robust in summer compared to other seasons. This could be associated with that higher resolution and detailed topography lead to more realistic simulation of heavy summer precipitation related to mesoscale phenomena.

This study investigated the future change in surface wind over the Korean Peninsula using a high-resolution climate change scenario projected by a regional climate model (RCM). In the evaluation of historical runs (1981-2010), the RCM reasonably reproduced a 30-year annual mean surface wind and it also represented climatological seasonal wind pattern properly. To examine the future change in surface wind, the results from RCP8.5 run for 30 years (2071-2100) were compared with those from historical run. Despite of slight differences among seasons, southerly differences were overall dominant. This indicated that southerly prevailing wind for summer was intensified in the future climate, while northerly prevailing wind for other seasons was reduced. The changes in the seasonal mean surface wind were significantly associated with those in the surface pressure distribution surrounding the Korean Peninsula. In the future climate, the monthly mean wind speed was reduced compared in the present climate. However, the magnitude and annual variability of the annual maximum wind speed tended to increase in the future climate.

Prognosis of the patients with lung cancer with lung-to-lung metastasis are known to be poor and frequently old aged persons with multiple nodules on imaging study abandon more invasive procedure including bronchoscopy and VATS (Videoassisted thoracoscopic surgery) to get tissue confirmation. Sjogren’s syndrome (SS) associated lung lesion mimicking lung cancer has a chance to have more favorable diseases including lymphoma. A 78-year-old woman with SS was admitted due to slowly progressive exertional dyspnea and multiple nodules on imaging study. She and her family gave up invasive diagnostic procedures at first due to old age but short term rapid change of dyspnea and nodules on chest CT brought out invasive procedures and diffuse large B-cell lymphoma was diagnosed. Dyspnea and nodules on imaging were improved after R-CHOP chemotherapy.