• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.7
• /
• pp.504-515
• /
• 2012

Groundwater is widely used as drinking water supplies around the world. However, microbial contamination of groundwater is a serious environmental problem that degrades drinking water quality and poses a great threat to human health. Among the pathogenic microorganisms such as viruses, bacteria, and protozoa, viruses are not readily removed during transport through soils, having high mobility in groundwater environment due to their smaller size compared to bacteria and protozoa. Studies regarding the fate and transport of viruses in soils and aquifers are necessary to determine the vulnerability of groundwater to microbial contamination and to secure safe drinking water sources. Also, these studies provide important information to establish the regulations and policies related to public health. This review paper presented the field and laboratory studies conducted for the fate and transport of viruses in subsurface environments. Also, the paper provided the factors affecting the fate and transport of viruses, the characteristics of bacteriophages used for virus studies, and virus transport model/colloid filtration theory. Based on this review work, future researches should be performed actively to set up the viral protection zone for the protection of groundwater from viral contamination sources. Especially, the researches should be focused on the development of mathematical models to calculate the setback distance and travel time for the viral protection zone along with the accumulation of information related to the model parameters.

• Journal of the Economic Geographical Society of Korea
• /
• v.17 no.1
• /
• pp.98-113
• /
• 2014

The purpose of this study is to investigate the changes in the accessibility of the Metropolitan Seoul Transit systems since 2000, in which many new subway lines have been constructed as well as other urban transit lines have been connected to the systems. We suggest an accessibility measure model for Un-fixed Transportation Networks. In order to measure the nodal accessibility based on the mobility, we apply path-distance, physical-distance, and time-distance as the distance impedance measurement. Specifically, we develop time-distance algorithms to measure the time-distance between each pairs of transit stations based on the T-card transaction databases. We apply the model to the Metropolitan Seoul Transit systems in two time points(2005 and 2011). We examine the results in terms of three distance accessibility measures. Time-distance accessibility explains better the urban land use patterns in the Metropolitan Seoul area than the other two. We visualize the spatial patterns of time-distance accessibility by applying GIS, and analyze the spatial structures of accessibility in the Metrropolitan Seoul area between two time points.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.31 no.4
• /
• pp.731-751
• /
• 2021

The Internet of Things is a huge group of devices communicating each other and the interconnection of objects in the network is a basic requirement. Choosing a reliable device is critical because malicious devices can compromise networks and services. However, it is difficult to create a trust management model due to the mobility and resource constraints of IoT devices. For the centralized approach, there are issues of single point of failure and resource expansion and for the distributed approach, it allows to expand network without additional equipment by interconnecting each other, but it has limitations in data exchange and storage with limited resources and is difficult to ensure consistency. Recently, trust management models using fog nodes and blockchain have been proposed. However, blockchain has problems of low throughput and delay. Therefore, in this paper, a trust management model for selecting reliable devices in a fog-based IoT environment is proposed by applying IOTA, a blockchain technology for the Internet of Things. In this model, Directed Acyclic Graph-based ledger structure manages trust data without falsification and improves the low throughput and scalability problems of blockchain.

• International Area Studies Review
• /
• v.14 no.3
• /
• pp.423-453
• /
• 2010

This study aims at quantifying potential economic effects on the Korean economy of a China-Korea FTA and a Japan-Korea FTA using a dynamic computable general equilibrium (CGE) model. Most of the previous studies on them used static CGE models. Key findings of this study are that a China-Korea FTA would lead to a higher increase in Korea's exports and economic growth than a Japan-Korea FTA and that both a China-Korea FTA and a Japan-Korea FTA would cause additional trade deficits to Korea, which would be minuscule compared to Korea' economic trade volume. Since potential economic impacts on Korea's industry output and exports by sector of a China-Korea FTA and a Japan-Korea FTA are forecast to be complementary, i.e., major sectors which would run trade deficits from a Japan-Korea FTA would run trade surpluses from a China-Korea FTA, a simultaneous pursuit of both a China-Korea FTA and a Japan-Korea FTA would be more desirable and beneficial to Korea. This study shows that a dynamic CGE model which can take explicit account of international capital mobility and ownership is required for more precise estimation of effects of the FTAs.

• Asian Spine Journal
• /
• v.12 no.6
• /
• pp.1060-1068
• /
• 2018

Study Design: Retrospective study. Purpose: Lumbar intervertebral disc degeneration is an important cause of low back pain. Overview of Literature: Spinal fusion is often reported to have a good course for adolescent idiopathic scoliosis (AIS). However, many studies have reported that adjacent segment degeneration is accelerated after lumbar spinal fusion. Radiography is a simple method used to evaluate the orientation of the vertebral column. magnetic resonance imaging (MRI) is the method most often used to specifically evaluate intervertebral disc degeneration. The Pfirrmann classification is a well-known method used to evaluate degenerative lumbar disease. After spinal fusion, an increase in stress, excess mobility, increased intra-disc pressure, and posterior displacement of the axis of motion have been observed in the adjacent segments. Methods: we retrospectively secured and analyzed the data of 15 patients (four boys and 11 girls) with AIS who underwent a spinal fusion surgery. We studied the full-length view of the spine (anterior-posterior and lateral) from the X-ray and MRI obtained from all patients before surgery. Postoperatively, another full-length spine X-ray and lumbosacral MRI were obtained from all participants. Then, pelvic tilt, sacral slope, curve correction, and fused and free segments before and after surgery were calculated based on X-ray studies. MRI images were used to estimate the degree to which intervertebral discs were degenerated using Pfirrmann grading system. Pfirrmann grade before and after surgery were compared with Wilcoxon signed rank test. While analyzing the contribution of potential risk factors for the post-spinal fusion Pfirrmann grade of disc degeneration, we used generalized linear models with robust standard error estimates to account for intraclass correlation that may have been present between discs of the same patient. Results: The mean age of the participant was 14 years, and the mean curvature before and after surgery were 67.8 and 23.8, respectively (p<0.05). During the median follow-up of 5 years, the mean degree of the disc degeneration significantly increased in all patients after surgery (p<0.05) with a Pfirrmann grade of 1 and 2.8 in the L2-L3 before and after surgery, respectively. The corresponding figures at L3-L4, L4-L5, and L5-S1 levels were 1.28 and 2.43, 1.07 and 2.35, and 1 and 2.33, respectively. The lower was the number of free discs below the fusion level, the higher was the Pfirrmann grade of degeneration (p<0.001). Conversely, the higher was the number of the discs fused together, the higher was the Pfirrmann grade. Conclusions: we observed that the disc degeneration aggravated after spinal fusion for scoliosis. While the degree of degeneration as measured by Pfirrmann grade was directly correlated by the number of fused segments, it was negatively correlated with the number of discs that remained free below the lowermost level of the fusion.

• Journal of Preventive Medicine and Public Health
• /
• v.56 no.5
• /
• pp.467-474
• /
• 2023

Objectives: Diabetes mellitus (DM) is a serious public health issue that places a heavy financial, social, and health-related burden on individuals, families, and healthcare systems. Self-reported health-related quality of life (HRQoL) is extensively used for monitoring the general population's health conditions and measuring the effectiveness of interventions. Therefore, this study investigated HRQoL and associated factors among patients with type 2 DM at a primary healthcare center in Indonesia. Methods: A cross-sectional study was conducted in Klaten District, Central Java, Indonesia, from May 2019 to July 2019. In total, 260 patients with DM registered with National Health Insurance were interviewed. HRQoL was measured with the EuroQol Group's validated Bahasa Indonesia version of the EuroQoL 5-Dimension 5-Level (EQ-5D-5L) with the Indonesian value set. Multivariate regression models were used to identify factors influencing HRQoL. Results: Data from 24 patients were excluded due to incomplete information. Most participants were men (60.6%), were aged above 50 years (91.5%), had less than a senior high school education (75.0%), and were unemployed (85.6%). The most frequent health problems were reported for the pain/discomfort dimension (64.0%) followed by anxiety (28.4%), mobility (17.8%), usual activities (10.6%), and self-care (6.8%). The average EuroQoL 5-Dimension (EQ-5D) index score was 0.86 (95% confidence interval [CI], 0.83 to 0.88). In the multivariate ordinal regression model, a higher education level (coefficient, 0.08; 95% CI, 0.02 to 0.14) was a significant predictor of the EQ-5D-5L utility score. Conclusions: Patients with diabetes had poorer EQ-5D-5L utility values than the general population. DM patients experienced pain/discomfort and anxiety. There was a substantial positive relationship between education level and HRQoL.

• Journal of agricultural medicine and community health
• /
• v.39 no.3
• /
• pp.176-186
• /
• 2014

Objectives: As a sequel to the former analysis of the quality of life (QoL) among young-old and old-old in Korea, this research was aimed to identify factors related to the quality of life and the gender difference after controlling for the related factors among Korean elderly. Methods: Selected elderly data of 1,339 subjects from the 5th Korea National Health and Nutrition Examination Survey conducted in 2010 was analyzed. In this survey, QoL was measured using Euro Quality of Life (EQ-5D) instrument. Data were analyzed using complex survey data analysis on IBM-SPSS 20.0. The related factors were identified using general linear models with backward elimination. The gender difference was tested also using general linear models. Results: The distributions of educational level, family income level, and presence of cohabitant were different between male and female elderly in both young-old and old-old age group. So were the health behaviors and perceived health, and experience of stress, depression, and suicidal thoughts. QoL and its subscales- mobility, self care, daily living, pain and discomfort, and anxiety and depression- were consistently better among male elderly regardless of age group. Among the variables considered, education, family income level, presence of cohabitant, perceived health, age group and BMI were found to be related to the QoL at p=.05, and presence of chronic diseases at p=.10. The difference in QoL between male and female elderly after controlling for the variables was statistically significant. Conclusion: Improving QoL is particularly important for the elderly. In order to improve QoL of the elderly, age- and gender- differences need to be considered when developing services and programs for the elderly.

• Korean Journal of Environmental Agriculture
• /
• v.35 no.1
• /
• pp.24-31
• /
• 2016

BACKGROUND: Heavy metal adsorption not only depends on rapid cooling slag(RCS) characteristics but also on the nature of the metals involved and on their competitive behavior for RCS adsorption sites. The goal of this study was to investigate the competitive absorption characteristics of Cu, Cd and Zn in single- and multi-metal forms by RCS.METHODS AND RESULTS: Both single- and multi-metal adsorption experiments were conducted to determine the adsorption characteristics of RCS for the heavy metals. Adsorption behaviors of the heavy metals by RCS were evaluated using both the Freundlich and Langmuir adsorption isotherm equations. The maximum adsorption capacities of metals by RCS were in the order of Cu(16.6 mg/g) > Cd(8.1 mg/g) > Zn(6.2 mg/g) in the single-metal adsorption isotherm and Cu(14.5 mg/g) >> Zn(1.3 mg/g) > Cd(0.6 mg/g) in the multi-metal adsorption isotherm. Based on data obtained from Freundlich and Langmuir adsorption models and three-dimensional simulation, multi-metal adsorption behaviors differed from single- metal adsorption due to competition. Cadmium and Zn were easily exchanged and substituted by Cu during multi-metal adsorption.CONCLUSION: Results from adsorption experiments indicate that competitive adsorption among metals increases the mobility of these metals.

• Journal of Life Science
• /
• v.33 no.3
• /
• pp.277-286
• /
• 2023

Sarcopenia is the age-related loss of muscle mass and function. It is a natural part of aging and can lead to decreased mobility and increased frailty. The ubiquitin-proteasome pathway, which is involved in muscle protein degradation, is closely linked to sarcopenia. Germinated Rhynchosia nulubilis hydrolysate (GRH) has been reported to have anti-inflammatory and antioxidant properties, but there have been no reports on its inhibitory effect on muscle reduction. However, no study has yet explored the relationship between GRH and muscle loss inhibition. In this study, we evaluated the effects of GRH on muscle atrophy inhibitory activity in dexamethasone (Dexa)-induced muscle atrophy C2C12 myotubes and mouse models. Moreover, we identified a molecular pathway underlying the effects of GRH on skeletal muscle. May Grunwald-Giemsa staining showed that the length and area of myotubes increased in the groups treated with GRH. In addition, the GRH-treated group significantly reduced the expression of muscle ring finger protein 1 and muscular atrophy F-box (MAFbx) in the Dexa-induced muscular atrophy C2C12 model. GRH also improved muscle strength in C57BL/6 mice with Dexa-induced muscle atrophy, resulting in prolonged running exhaustive time and increased grip strength. We found that muscle strengthening by GRH was correlated with a decreased expression of the MAFbx gene in mouse muscle tissue. In conclusion, GRH can attenuate Dexa-induced muscle atrophy by inhibiting the ubiquitin-proteasome pathway via downregulation of the MAFbx gene expression.