• Imaging Science in Dentistry
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• v.53 no.2
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• pp.91-99
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• 2023

Purpose: This systematic review aimed to investigate the correlation between chronological age and dental pulp volume in cone-beam computed tomography (CBCT). Materials and Methods: The literature was searched in 4 databases(PubMed, Scopus, Web of Science, and Google Scholar). Within each study, the outcome of interest was the correlation (r) between chronological age and pulp volume. A random-effect meta-analysis was conducted. Subgroup analysis was carried out according to sex and tooth type. Results: Of 5,693 identified studies, 27 fulfilled the inclusion criteria and were selected for meta-analysis. These articles focused on single-rooted teeth (n=21), multi-rooted teeth (n=6), maxillary teeth (n=14), mandibular teeth (n=6), and maxillary and mandibular teeth (n=12). The relationship between chronological age and dental pulp volume was examined in the entire population (r= -0.67), men (r= -0.75), and women (r= -0.77) in single- and multi-rooted teeth. The results of the total population analysis showed a relatively strong negative relationship between age and pulp volume. Conclusion: This study suggested that CBCT is a reliable and repeatable tool for dental age estimation. A strong inverse relationship was observed between pulp chamber volume and age. Further studies on the correlation between chronological age and pulp volume of multi-rooted teeth may be beneficial.

• Journal of Forest and Environmental Science
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• v.39 no.4
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• pp.213-224
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• 2023

As abnormal weather events due to climate change continue to rise, landslide damage is also increasing. Given the substantial time and financial resources required for post-landslide recovery, it becomes imperative to formulate a proactive response plan. In this regard, landslide susceptibility analysis has emerged as a valuable tool for establishing preemptive measures against landslides. Accordingly, this study conducted an annual landslide susceptibility analysis using the history of landslides that occurred over many years in the Jeolla region, and analyzed areas with a high potential for landslides in the Jeolla region. The analysis employed an ensemble model that amalgamated 10 data-based models, aiming to mitigate uncertainties associated with a single-model approach. Furthermore, based on the cumulative data regarding landslide susceptible areas, this research identified regions vulnerable to recurring landslide damage in Jeolla region and proposed specific strategies for utilizing this information at various levels, including local government initiatives, adaptation plan development, and development approval processes. In particular, this study outlined approaches for local government utilization, the determination of adaptation plan types, and considerations for development permits. It is anticipated that this research will serve as a valuable opportunity to underscore the significance of information concerning regions vulnerable to recurring landslide damage.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.2
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• pp.159-165
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• 2024

The Global Navigation Satellite System (GNSS) has been used as a tool to accurately extract the Total Electron Content (TEC) in the ionosphere. The multi-GNSS (GPS, GLONASS, BeiDou, Galileo, and QZSS) constellations bring new opportunities for ionospheric research. In this study, we develop a regional ionospheric TEC model using GPS, Galileo, and QZSS measurements. To develop an ionospheric model covering the Asia-Oceania region, we select 13 International GNSS Service (IGS) stations. The ionospheric model applies the spherical harmonic expansion method and has a spatial resolution of 2.5°×2.5° and a temporal resolution of one hour. GPS TEC, Galileo TEC, and QZSS TEC are investigated from January 1 to January 31, 2024. Different TEC values are in good agreement with each other. In addition, we compare the QZSS(J07) TEC and the Center for Orbit Determination in Europe (CODE) Global Ionosphere Map (GIM) TEC. The results show that the QZSS TEC estimated in the study coincides closely with the CODE GIM TEC.

• Korean Journal of Social Welfare
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• v.60 no.2
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• pp.5-28
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• 2008

This study tried to develop an test tool of social workers' ethical sensitivity(SWEST) on base of realization about the importance of ethical sensitivity of social worker who are required more ethicalities than the other professionals. Nevertheless, there has been no tool that can measure ethical sensitivity of social workers in our country up to now. Through analysis of existing ethical sensitivity tests in other professions, a paper and pencil method about unstructured question with cases including ethical issues and structured scoring system was chosen as an appropriate method for the SWEST. This study progressed in order : 1st collecting cases, 2nd composing cases, 3rd consulting cases, 4th pilot study, 5th making scoring standards, 6th determining case examples and scoring standards. With the result, the tool consists of 3 case examples with ethical issues : 1) self-determination and confidentiality, 2) equality and double relationship, 3) informed consent and conflict interest. And ethical sensitivities of social work major students and social workers were measured with the SWEST, to see practical utility of this test. The agreement degrees between two independent raters were above 90%. And respondent's ethical sensitivity displayed the most definite difference according to taking or not taking a course 'Social work values and ethics'. Through these results, it can be drawn that the SWEST is reliable and valid to test relevant differences in Korean social workers' ethical sensitivity. The SWEST is expected to activate studying, educating, and practicing ethics in social work.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.130-145
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• 2016

Soil erosion processes are affected by weather factors, such as rainfall, temperature, wind, and humidity. Among these factors, rainfall directly influences soil erosion by breaking away soil particles. The kinetic energy of rainfall and water flow caused by rain entrains and transports soil particles downstream. Therefore, in order to estimate soil erosion, it is important to accurately determine the rainfall erosivity factor(R) in RUSLE(Revised Universal Soil Loss Equation). The objective of this study is to evaluate the average annual R using 14 years(2002~2015) of 1 minute rainfall data from 55 KMA(Korea Meteorological Administration) weather stations. The R results from 1 min rainfall were compared with previous R studies using 1 h rainfall data. The determination coefficients($R^2$) between R calculated using 1 min rainfall data and annual rainfall were 0.70-0.98. The estimation of 30 min rainfall intensity from 1 min rainfall data showed better $R^2$ results than results from 1 h rainfall data. For estimation of physical spatial rain erosivity(R), distribution of annual rainfall was estimated by IDW(Inverse Distance Weights) interpolation, taking elevation into consideration. Because of the computation burden, the R calculation process was programmed using the python GUI(Graphical User Interface) tool.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.547-554
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• 2010

Purpose: The purpose of this study is to delineate the optimal time of venous revascularization for preventing the flap necrosis due to venous occlusion, and to clarify the usefulness of tissue oxygen pressure ($TcpO_2$) in the determination of the point of time for venous revascularization. Methods: Thirty-six, $3{\times}3\;cm$ sized epigastric island flap was elevated in left abdomen of male Sprague-Dawley rat weighing 250 gram. Flaps were randomly assigned to six groups of six flaps according to the duration of venous occlusion with microvascular clamp; 10 minutes in the group I as the control, 60 minutes in the group II, 2 hours in the group III, 3 hours in the group IV, 4 hours in the group V, and 6 hours in the group VI, respectively. Just before removal of clamp after flap was reposed in situ, the ratio of $TcpO_2$ (tissue oxygen pressure) of the island flap to that of right abdomen was calculated in each group, and tissue specimen was harvested from the distal area of the flap for histological evaluation of vascular change. Five days later, survival area of the flap was estimated, and evaluated the correlation between the tissue oxygen pressure and the rate of flap survival. Results: The $TcpO_2$ and the survival rate of flap were decreased proportionally with the duration of venous occlusion. The ratio of the $TcpO_2$ of the flap is decreased abruptly to below sixty percentile compared to the $TcpO_2$ of normal tissue, and the survived area of the flap is decreased to nine-tenth of the designed size after three hours of total venous occlusion. Histologically, the number of congested vessels was increased according to venous occluded time, and proportionally increased after 3-hours of occlusion significantly. Conclusion: There is a close correlation between the $TcpO_2$ and the survival rate of flaps according to the duration of venous occlusion. Therefore, the $TcpO_2$ represents the hemodynamic changes within the flap, and thought to be an alternative effective tool in the flap monitoring for venous revascularization.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.175-184
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• 2013

Organic carbon and total nitrogen stable isotope ratios of suspended materials were determined at 3 stations (from Mongtan Bridge to Youngsan river estuary barrage) (n=6, each) from November 2008 to August 2009, in order to understand the origin of particulate organic matter at the Estuary of Youngsan River. Allochthonous organic matter, ammonia-N and silicate were increased after heavy rain (in August). Carbon isotope ratios were significantly different between stations in November and August, and it was possible to determine the origin of organic matter. The heavier nitrogen isotope ratios, as well as higher phosphate concentrations, were found in November than other sampling times. Livestock wastewater and farmland input was likely the main causes of these high values. In addition, YS3 station, the nearest site to estuary barrage, appears to be affected by a substantial amount of livestock wastewater and farmland input, considering that nitrogen isotope ratios were heavier than those at the upper sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the determination of organic matter origin in aquatic environments.

• Korean Journal of Veterinary Research
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• v.40 no.4
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• pp.741-746
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• 2000

We have developed a rapid, simple and precise high-performance liquid chromatographic (HPLC) method using an UV detection system for the determination of new anti-HIV candidates, nineteen KR-V compounds, in rat plasma. We used a analytical columnn of $C_{18}$ ($5{\mu}m$, $250{\times}2.0mm$ I.D.) and a mobile phase of water and ACN mixture (40/60, v/v). Under these conditions, all the KR-V compounds were readily separated from plasma with retention times of 4-12 min. The limits of quantitation for the 19 KR-V compounds were 15-30 ng/ml. The recoveries from the plasma were higher than 85% (C.V.<10%) with exception of KR-V 2, 7 and 15. The compounds KR-V 2, 7 and 15, containing ester moieties, were found to be unstable in plasma. This result suggests that esters, like KR -V 2, 7 and 15, should be excluded from future structure design studies of anti-HIV KR-V agents. In conclusion, the current HPLC method is a valuable analytical tool for investigating the pharmacokinetics of the KR-V series in rats.

• Analytical Science and Technology
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• v.14 no.3
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• pp.244-252
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• 2001

A comprehensive analytical method of endocrine distruptors[i.e., nonylphenol(NP), octylphenol(OP), bis(2-ethylhexyl)phthalate(BEHP)] is fish samples was developed using two internal standards. This method employed closed culture tube extraction with dichloromethane and solvent exchange to iso-hexane and SPE(2g) aminopropyl column, followed by determination on gas chromatograph linked to mass spectrometer(GC/MS) operated in the single ion monitoring(SIM) mode. The recoveries of nonylphenol and octyphenol in the range of $0.2{\sim}20{\mu}g/g$ using 1-phenyl decanol as one internal standard were over 75%, and recovery of bis(2-ethylhexyl)phthalate in the range of $0.4{\sim}40{\mu}g/g$ using bis(2-ethylbutyl)phthalate(BEBP) as the other internal standards was showed over 102%. The present method was applied to fish samples from Korea and UK. The range of concentrations for nonylphnol(NP) and bis(2-ethylhexyl)phthalate in Korean fish were $0.02{\sim}0.06{\mu}g/g$ in 2 samples and $0.18{\sim}2.03{\mu}g/g$ in 9 samples respectively, but bis(2-ethylhexyl)phthalate(BEHP) in UK samples was found $2.99{\mu}g/g$ in just 1 sample. But octylphenol(OP) was not dected in any samples by this method. This two internal standard method provides a more precise analytical tool to investigate endocrine disruptors in a biological matrices of limited quantity.

• Analytical Science and Technology
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• v.28 no.1
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• pp.33-39
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• 2015

CdS-QD particles are a nano-sized semiconducting crystal that emits light. Their optical properties show great potential in many areas of applications such as disease-diagnostic reagents, optical technologies, media industries and solar cells. The wavelength of emitting light depends on the particle size and thus the quality control of CdS-QD particle requires accurate determination of the size distribution. In this study, CdS-QD particles were synthesized by a simple ${\gamma}$-ray irradiation method. As a particle stabilizer polyvinyl pyrrolidone (PVP) were added. In order to determine the size and size distribution of the CdS-QD particles, sedimentation field-flow fractionation (SdFFF) was employed. Effects of carious parameters including the the flow rate, external field strength, and field programming conditions were investigated to optimize SdFFF for analysis of CdS-QD particles. The Transmission electron microscopy (TEM) analysis show the primary single particle size was ~4 nm, TEM images indicate that the primarty particles were aggregated to form secondary particles having the mean size of about 159 nm. As the concentration of the stabilizer increases, the particle size tends to decrease. Mean size determined by SdFFF, TEM, and dynamic light scattering (DLS) were 126, 159, and 152 nm, respectively. Results showed SdFFF may become a useful tool for determination of the size and its distribution of various types of inorganic particles.