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Aims: To evaluate the effects of initiating sodium‐glucose cotransporter‐2 (SGLT2) inhibitors on cardiorenal outcomes and mortality compared to dipeptidyl peptidase‐4 (DPP‐4) inhibitors as active comparators in patients diagnosed with type 2 diabetes with a history of percutaneous coronary intervention (PCI). Materials and Methods: We used an active‐comparator, new‐user design and nationwide data from the National Health Insurance Service in South Korea from 2014 to 2019. Of the 56 392 patients who underwent PCI, 4610 new SGLT2 inhibitor users were paired 1:1 with DPP‐4 inhibitor users for analysis using propensity‐score matching. Results: During 13 708.59 person‐years of follow‐up, the initiation of SGLT2 inhibitors, compared with the initiation of DPP‐4 inhibitors, was associated with a significantly lower risk of composite repeat revascularization, myocardial infarction, stroke, heart failure (HF), all‐cause death and end‐stage renal disease (ESRD). The beneficial effects of SGLT2 inhibitor use were consistent with the components of stroke, HF, all‐cause death and ESRD. In the cohort that included health examination data, including anthropometric and metabolic factors, new use of SGLT2 inhibitors was associated with a significantly lower risk of HF (hazard ratio [HR] 0.574, 95% confidence interval [CI] 0.36–0.915), all‐cause death (HR 0.731, 95% CI 0.567–0.942), and ESRD (HR 0.076, 95% CI 0.018–0.319). The effects of SGLT2 inhibitor use were consistent regardless of the timing of the previous PCI. Conclusions: The initiation of SGLT2 inhibitors in patients with type 2 diabetes and a history of PCI was significantly associated with a reduced risk of cardiorenal consequences and mortality, irrespective of time since the last PCI. [ABSTRACT FROM AUTHOR]

Objective: Hyperuricemia might have neuroprotective or neurodegenerative effects on dementia via oxidative stress or inflammatory response regulation. Few studies have explored the association of hyperuricemia or gout with dementia. This retrospective cohort study aimed to investigate the association between gout and dementia in Korea. Methods: Altogether, 5,052 gout patients and 25,260 age‐ and sex‐matched controls were selected from the National Health Insurance Service (NHIS)–National Sample Cohort database. The incidence and risk of dementia were evaluated by reviewing the NHIS record. We also performed a subgroup analysis according to age group (age <65 or ≥65 years) using the standard age of 65 years for elderly and nonelderly groups and sex. Results: During follow‐up, 81 and 558 participants in the gout and control cohorts developed dementia, respectively. The mean follow‐up duration was 4.38 years in gout patients and 4.94 years in controls. Gout patients had a hazard ratio (HR) of 0.79 for overall dementia (95% confidence interval [95% CI] 0.62–1.00) and significantly lower Alzheimer's disease risk (HR 0.73 [95% CI 0.54–0.98]) after adjusting for age, sex, household income, and comorbidities. In subgroup analysis stratified by age and sex, the inverse association between gout and the risk of overall dementia (HR 0.71 [95% CI 0.52–0.97]) and Alzheimer's disease (HR 0.67 [95% CI 0.46–0.97]) were observed in the elderly male group. On the other hand, age‐ and sex‐adjusted analysis showed that the HR for vascular dementia of gout patients was 2.31 (95% CI 1.02–5.25) in the nonelderly male group. Conclusion: Gout decreased the risk of incident Alzheimer's disease–type dementia, especially in elderly patients. The association between gout and dementia risk may differ according to age and disease duration. [ABSTRACT FROM AUTHOR]

Simple Summary: With the development of new chemotherapeutic agents and advances in surgical techniques, the overall survival of gastric cancer patients continues to rise. Long-term follow-up of gastric cancer patients has resulted in an increase in the number of reports of secondary primary cancer (SPC) in these patients. This review analyzes the SPCs of gastric cancer survivors using the nationwide claims data of Republic of Korea, and summarizes previous studies of the incidence of SPC in national and institutional databases. Advances in cancer screening and early detection, as well as improvements in surgical techniques and therapeutics, have contributed to decreasing gastric cancer mortality. The number of gastric cancer survivors continues to rise; however, long-term follow-up has revealed an increase in the risk of post-gastrectomy symptoms or other health problems, such as extra-gastric secondary primary cancer (SPC), in these survivors. Therefore, evidence-based screening for new primary cancer is needed in these populations; however, the incidence of SPC varies by country or continent and its characteristics have not been clearly reported. The characteristics of SPC are of increasing interest to both treatment providers and gastric cancer survivors; thus, this literature review explores not only the epidemiology and biology of SPC but also clinical and biological factors that influence its prognosis. [ABSTRACT FROM AUTHOR]

Background: Three industrial waste incinerators (IWIs) were built in 1999, 2001, and 2010, within a 3 km radius of a town with a population of around 5000 in Korea. This study evaluated whether residents near these three IWIs had increased cancer incidence than those from other areas in Korea using regional health data. Methods: Standardized incidence ratios (SIR) were calculated using the frequency of cancer cases in the National Cancer Registry of the exposed area (Buki-myeon), Chungcheongbuk-do (Chungbuk, state including Buki-myeon), and whole Korea from 1999 to 2017. A retrospective cohort was created using National Health Insurance System data from 2002 to 2018. The exposed group was defined as those having a residential history in the exposed area. The control group was defined as those having a residential history in nearby towns or counties in Chungbuk, excluding counties having living and cultural areas in other provinces and cities. Hazard ratio (HR) and 95% confidence intervals (CI) were estimated using the Cox proportional hazard model adjusted for age, level of health insurance fee, and smoking history. Results: In the ecological study using National Cancer Registry data, the risk of all cancers, all cancers excluding thyroid, esophageal, stomach, and lung cancers in the exposed area were 1.13 (95% CI 1.03–1.24), 1.15 (95% CI 1.04–1.26), 1.91 (95% CI 1.13–2.89), 1.39 (95% CI 1.14–1.66), and 1.29 (95% CI 1.03–1.57) times higher than in whole Korea among exposed males, respectively. In the retrospective cohort, 4300 males (26,821 person-years) and 3796 females (24,746 person-years) in exposed group, 150,964 males (1,212,010 person-years) and 134,535 females (1,104,025 person-years) in control group were analyzed. After adjusting for several confounding factors, the risks for gallbladder cancer among males and kidney cancer among females were 2.65 (95% CI 1.38–5.06) and 2.82 (95% CI 1.13–7.03) times higher in the exposed group versus the control group, respectively. Conclusions: Cancer risk was higher in Koreans having residential history living near IWIs compared to the other areas. Further study warrants nationwide effects and longer follow-up of WIs for cancers in Korea. [ABSTRACT FROM AUTHOR]

Particulate matter (PM), an extremely serious type of air pollution, leads to numerous human diseases. Mitigating PM in the urban city, where resident density has been increasing, has been a major challenge. The increase in residents leads to increasing traffic, the primary source of PM in urban areas. Plants play an important role in reducing PM and maintaining an ecological balance. For some Asian countries, such as Korea, with differing seasons and environmental conditions, PM accumulation and plant survival are greatly impacted by environmental conditions. In this study, we analyzed the amount of PM accumulation on the leaf surfaces and wax layers of 24 plant species during four seasons (spring, summer, autumn, and winter) to determine the PM accumulation in plants under different environmental conditions. The leaf traits of plant chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll (TChl), relative water content (RWC), leaf extract pH (pH), and leaf specific area (SLA) were analyzed to determine the influence of PM on plants and the relationship between PM and leaf traits. In this study, we found that the amount of PM accumulation differed among plants and seasons. Among the 24 plant species, plants Pinus strobus, P. parviflora, P. densiflora, Euonymus japonicus, and Acer palmatum were most adept at PM accumulation. Leaf structure, environmental conditions, such as PM concentration, and rainfall may be the main factors that impact the ability of plant leaves to accumulate PM. The plant leaf traits differed among the four seasons. PM accumulation on the leaf was negatively correlated with SLA (in all four seasons) and pH (in spring, summer, and autumn). PM was negatively correlated with Chl a, Chl b, and TChl in summer. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) is the most dangerous form of air pollution and is known to cause severe health problems to humans. Plants as biological filters can reduce PM in urban areas by accumulating PM on the surface and epicuticular wax of leaves. The present study determined the amount of PM (large PM (10–100 µm) and coarse PM (2.5–10 µm)) collected on 10 plant species from two sites (urban forest and roadside) of Cheongju City, South Korea. Selected leaf traits (chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll (TChl), carotenoid, relative leaf water content (RWC), specific leaf area (SLA), and pH of these plant species at the two sites were concurrently determined to find about the correlation between the leaf straits and PM accumulation on leaf. Study results showed that the amount of accumulated large PM (10–100 µm) and coarse PM (2.5–10 µm) were different depending on the plant species and the collection site. Plants from the roadside tended to have higher amounts of PM accumulation as compared to the same plant species from the urban forest. In addition, the amount of PM accumulated on the leaf surface was higher than that of the epicuticular wax. PM accumulation on the leaf surface was positively correlated with the amount of PM accumulated on the epicuticular wax. Among the 10 plant species selected, P. strobus, P. densiflora, M. denudata, and S. vulgaris were the most effective plant for PM accumulation, while M. glyptostroboides was the least effective plant ones. Chl a, Chl b, TChl, and carotenoid contents were higher in plants collected along the roadside than in those collected from the urban forest, whereas RWC was higher in plants from the urban forest. No distinct tendency was noted regarding the pH. Coarse PM (2.5–10 µm) was negatively correlated with leaf traits of plants along the roadside. The tolerance of plants to pollution might be due to an increase in chlorophyll content. Features of the leaf were also essential in increasing PM accumulation on the leaf surface. [ABSTRACT FROM AUTHOR]

Purpose: The authors examine cryptocurrency market behavior using a hidden Markov model (HMM). Under the assumption that the cryptocurrency market has unobserved heterogeneity, an HMM allows us to study (1) the extent to which cryptocurrency markets shift due to interactions with social sentiment during a bull or bear market and (2) the heterogeneous pattern of cryptocurrency market behavior under these two market conditions. Design/methodology/approach: The authors advance the HMM model based on two six-month datasets (from November 2017 to April 2018 for a bull market and from December 2018 to May 2019 for a bear market) collected from Google, Twitter, the stock market and cryptocurrency trading platforms in South Korea. Social sentiment data were collected by crawling Bitcoin-related posts on Twitter. Findings: The authors highlight the reaction of the cryptocurrency market to social sentiment under a bull and a bear market and in two hidden states (an upward and a downward trend). They find: (1) social sentiment is relatively relevant during a bull compared to a bear market. (2) The cryptocurrency market in a downward state, that is, with a local decreasing trend, tends to be more responsive to positive social sentiment. (3) The market in an upward state, that is, with a local increasing trend, tends to better interact with negative social sentiment. Originality/value: The proposed HMM model contributes to a theoretically grounded understanding of how cryptocurrency markets respond to social sentiment in bull and bear markets through varied sequences adjusted for cryptocurrency market heterogeneity. [ABSTRACT FROM AUTHOR]

Background: To evaluate the effects of teneligliptin on glycosylated hemoglobin (HbA1c) levels, continuous glucose monitoring (CGM)-derived time in range, and glycemic variability in elderly type 2 diabetes mellitus patients. Methods: This randomized, double-blinded, placebo-controlled study was conducted in eight centers in Korea (clinical trial registration number: NCT03508323). Sixty-five participants aged ≥65 years, who were treatment-naïve or had been treated with stable doses of metformin, were randomized at a 1:1 ratio to receive 20 mg of teneligliptin (n=35) or placebo (n=30) for 12 weeks. The main endpoints were the changes in HbA1c levels from baseline to week 12, CGM metrics-derived time in range, and glycemic variability. Results: After 12 weeks, a significant reduction (by 0.84%) in HbA1c levels was observed in the teneligliptin group compared to that in the placebo group (by 0.08%), with a between-group least squares mean difference of -0.76% (95% confidence interval [CI], -1.08 to -0.44). The coefficient of variation, standard deviation, and mean amplitude of glycemic excursion significantly decreased in participants treated with teneligliptin as compared to those in the placebo group. Teneligliptin treatment significantly decreased the time spent above 180 or 250 mg/dL, respectively, without increasing the time spent below 70 mg/dL. The mean percentage of time for which glucose levels remained in the 70 to 180 mg/dL time in range (TIR70-180) at week 12 was 82.0%±16.0% in the teneligliptin group, and placebo-adjusted change in TIR70-180 from baseline was 13.3% (95% CI, 6.0 to 20.6). Conclusion: Teneligliptin effectively reduced HbA1c levels, time spent above the target range, and glycemic variability, without increasing hypoglycemia in our study population. [ABSTRACT FROM AUTHOR]

Background: Euphorbia jolkinii Boiss. is a perennial species native to Jeju Island and the southern coastal area of Korea. Particularly on Jeju Island, the yellow flowers of E. jolkinii Boiss. have a high ornamental value because of their contrast with basalt. This study was conducted to investigate the effects of different temperatures (5, 15, 20, and 25 °C) and gibberellic acid (GA3) concentrations (0, 10, 100, or 1000 mg/L) on seed dormancy and germination of E. jolkinii. In addition, we classified the seed dormancy type and compared types with those of other species in the same genus. Results: The number of seeds with viable embryos and endosperms was approximately 66%. The final germination percentages at 5, 15, 20, and 25 °C were 51.7%, 83.5%, 2.6%, and 0.0%, respectively. In GA3 concentration experiments, the final germination percentages of 0, 10, 100, and 1000 mg/L were 83.5%, 91.7%, 79.1%, and 83.4%, respectively, at 15 °C conditions, and 0.0%, 6.9%, 13.2%, and 27.3%, respectively, at 25 °C. Conclusions: Germination improved at temperatures of 15 °C or lower. Furthermore, GA3 treatment effectively reduced germination times. Thus, the seeds of E. jolkinni were classified as having non-deep physiological dormancy. [ABSTRACT FROM AUTHOR]

Groundwater decrease and quality deterioration are common phenomena at coastal areas with subway tunnels in the world. This study investigated the problems in Busan Metropolitan City of Korea, using the integrated techniques of hydrogeological, hydro-geochemical, geostatistical, multivariate statistical and isotopic analyses. Groundwater around the subway was heavily discharged, and the groundwater level around the subway was fallen to −25.3 m on basis of mean sea level. The deep drawdown of groundwater level spurred the induction of seawater and salinized river water toward the inland area, and the groundwater was contaminated around the subway. This study identified that groundwater-level largely descended due to the excessive utilization of groundwater and the severe groundwater discharge from the subway tunnels, and that seawater and salinized river water intruded the inland groundwater and contaminated the groundwater around the subway. It is considered that this study will contribute to the investigation for the causes of groundwater decrease and contamination around subway tunnels in the worldwide metropolitan cities as well as the Busan City of Korea. [ABSTRACT FROM AUTHOR]

Background: Only few studies have shown the efficacy and safety of glucose-control strategies using the quadruple drug combination. Therefore, the aim of the present study was to investigate the usefulness of the quadruple combination therapy with oral hypoglycemic agents (OHAs) in patients with uncontrolled type 2 diabetes mellitus (T2DM). Methods: From March 2014 to December 2018, data of patients with T2DM, who were treated with quadruple hypoglycemic medications for over 12 months in 11 hospitals in South Korea, were reviewed retrospectively. We compared glycosylated hemoglobin (HbA1c) levels before and 12 months after quadruple treatment with OHAs. The safety, maintenance rate, and therapeutic patterns after failure of the quadruple therapy were also evaluated. Results: In total, 357 patients were enrolled for quadruple OHA therapy, and the baseline HbA1c level was 9.0%±1.3% (74.9± 14.1 mmol/mol). After 12 months, 270 patients (75.6%) adhered to the quadruple therapy and HbA1c was significantly reduced from 8.9%±1.2% to 7.8%±1.3% (mean change, -1.1%±1.2%; P<0.001). The number of patients with HbA1c <7% increased significantly from 5 to 68 (P<0.005). In addition, lipid profiles and liver enzyme levels were also improved whereas no changes in body weight. There was no significant safety issue in patients treated with quadruple OHA therapy. Conclusion: This study shows the therapeutic efficacy of the quadruple OHA regimen T2DM and demonstrates that it can be an option for the management of T2DM patients who cannot use insulin or reject injectable therapy. [ABSTRACT FROM AUTHOR]

This study investigates the factors weakening the relationship between a customer's cross-buying and firm sales in a multi-vendor loyalty program (MVLP) in Korea. The findings indicate that cross-buying has a positive impact on purchase frequency, transaction size, and further cross-buying in the subsequent periods. However, this impact is attenuated when customers are inclined to deal proneness or spending limit. The findings give academics and managers the opportunity to reconsider the conventional assumptions about cross-buying. Instead of emphasizing cross-selling for random customers, firms must identify customers whose cross-buying behavior affects firm performance positively. This study has managerial implications for MVLP operators for the effective acquisition and retention of participating vendors. [ABSTRACT FROM AUTHOR]

The Committee of Clinical Practice Guidelines of the Korean Diabetes Association (KDA) updated the previous clinical practice guidelines for Korean adults with diabetes and prediabetes and published the seventh edition in May 2021. We performed a comprehensive systematic review of recent clinical trials and evidence that could be applicable in real-world practice and suitable for the Korean population. The guideline is provided for all healthcare providers including physicians, diabetes experts, and certified diabetes educators across the country who manage patients with diabetes or the individuals at the risk of developing diabetes mellitus. The recommendations for screening diabetes and glucose-lowering agents have been revised and updated. New sections for continuous glucose monitoring, insulin pump use, and non-alcoholic fatty liver disease in patients with diabetes mellitus have been added. The KDA recommends active vaccination for coronavirus disease 2019 in patients with diabetes during the pandemic. An abridgement that contains practical information for patient education and systematic management in the clinic was published separately. [ABSTRACT FROM AUTHOR]

People living near abandoned mines are at increased risk of exposure to toxic metals. We surveyed 4500 inhabitants with the mean age of 68.5 years old (male: 1768, female: 2732) living near 104 abandoned metal mines from 2013 to 2017 (the 2nd phase health survey in Korea). We conducted personal interviews, blood and urine sampling, and analyzed the concentrations of lead (Pb) and cadmium (Cd) in whole blood and Cd in urine using a graphite furnace atomic absorption spectrometer. The geometric means of blood Pb, blood Cd, and urine Cd were 2.27 μg/dL, 1.42 μg/L, and 1.66 μg/g creatinine, respectively. The level of metal exposure was lower than that reported from the first phase health survey in Korea (2008‒2011) but was higher than in the general population of Korea. Blood Pb was higher in males while blood Cd and urine Cd were significantly higher in females. Blood Pb was highest in the 40‒59 age group, while blood and urine Cd levels continuously increased until age 80 or older. The Cd levels in blood and urine were affected by consumption of locally produced rice and duration of residence near abandoned mines. Furthermore, negative correlations were observed between blood Pb and blood and urine Cd levels. Additionally, 252 of the 4500 subjects exceeded the thresholds of blood Cd or urine Cd levels. Together, these findings suggest that Cd has more sustainable and adverse health effects on the abandoned mine inhabitants, who are mostly aged. Therefore, continuous biomonitoring and risk assessment to environmental health risks are necessary for environmental pollution control and health promotion. [ABSTRACT FROM AUTHOR]

This study examined how information communication technologies (ICT) investment affected sales and employment at 76 small and medium-sized Korean companies during 2009–2013. Especially, this study investigated the effects of ICT investment on sales in general and by subsets of investment in hardware, software, and ICT staff. Studies normally assumed a standard Cobb-Douglas production function, and measured variables in logarithms. In line with previous studies, we assumed that firms produced output, performance, or productivity via a Cobb–Douglas production function model with inputs capital and labor. We then suggested a new model that could be incorporated into the production function above to estimate the effect of the interaction between ICT investment and labor on sales. This study found that hardware investment complemented labor in increasing performance, whereas investments in software and ICT staff substituted labor. These results show that ICT investment might affect firm-level employment, and what business managers must consider insofar as each subset of ICT investment exerts differing effects on firm-level employment. This study also found that the effect of ICT investment on firm-level employment might be more pronounced among smaller firms and firms outside the IT industry. This study also demonstrated that ICT investment complemented labor and that the effects differed for specific types of ICT. This study can help managers respond to the challenges of ICT investment or employment, and provides a framework for analyzing the strategic significance of ICT investment and employment. [ABSTRACT FROM AUTHOR]

This study is to assess the hydrogeochemical characteristics of groundwater at the deltaic region of the Nakdong River Basin in the Busan Metropolitan City of Korea. The study area is covered by the Quaternary sedimentary deposits and the Cretaceous granites associated with unconformity. The thick sedimentary deposits consists of two aquifers, i.e., unconfined and confined aquifers on the basis of clay deposit. Groundwater samples were collected from seven boreholes: two from unconfined aquifer and five from confined aquifer systems during the wet season of 2017 year. ORP and DO indicates that the groundwater of the unconfined aquifer exists in the oxidization condition and that of the confined aquifer pertains in the reduction condition. Piper's trilinear diagram shows CaSO4 type for groundwater of the unconfined aquifer, and NaCl type for that of the confined aquifer. Ionic concentrations of groundwater increase in the confined aquifer because of direct and reverse ion exchange processes. Carbonate weathering and evaporation are other mechanisms in the water-rock interaction. Saturation indices of dolomite and calcite are observed as oversaturated, while halite reveals undersaturation. Hierarchical cluster analysis (HCA) exhibits that cluster 1 and cluster 2 represents the properties of groundwater in unconfined and confined aquifers, respectively. Factor analysis shows that groundwater of the confined aquifer is much influenced by seawater, and includes heavy metals of iron and aluminum. Groundwater samples in unconfined and confined aquifers are located at the rock weathering and evaporation zones in the Gibbs diagram. Inverse geochemical modeling of PHREEQC code suggests that carbonate dissolution and ion exchange of major ions are the prevailing geochemical processes. This comprehensive research provides the distinguished hydrogeochemical characteristics of groundwater in confined and unconfined aquifer systems of the Nakdong River Basin in Busan City, Korea. [ABSTRACT FROM AUTHOR]

Background: Lead (Pb) is a ubiquitous toxic metal present in the environment that poses adverse health effects to humans. Inter-individual variation in blood Pb levels is affected by various factors, including genetic makeup. However, limited data are available on the association between genetic variation and blood Pb levels. The purpose of this study was to identify the genetic markers associated with blood Pb levels in the Korean population.Methods: The study subjects consisted of 1,483 healthy adults with no history of occupational exposure to Pb. We measured blood Pb levels and calculated probable daily intake of Pb according to dietary data collected using 24-hour recall. We conducted exome-wide association screening using Illumina Human Exome-12v1.2 platform (n = 500) and a replication analysis using VeraCode Goldengate assay (n = 1,483).Results: Among the 244,770 single nucleotide polymorphisms (SNPs) tested, 12 SNPs associated with blood Pb level were identified, with suggestive significance level (P < 1 × 10-4). In the Goldengate assay for replication, three SNPs (C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671) were associated with statistically suggestively significant differences in blood Pb levels. When stratified by drinking status, a potential association of C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 with blood Pb level was observed only in drinkers. A marginally significant gene-environment interaction between ALDH2 rs671 and alcohol consumption was observed in relation to blood Pb levels. The effects of the three suggestively significant SNPs on blood Pb levels was dependent on daily calcium intake amounts.Conclusions: This exome-wide association study indicated that C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 polymorphisms are linked to blood Pb levels in the Korean population. Our results suggest that these three SNPs are involved in the determination of Pb levels in Koreans via the regulation of alcohol drinking behavior, and that their negative effects may be compensated by appropriate calcium intake. [ABSTRACT FROM AUTHOR]

The Committee of Clinical Practice Guidelines of the Korean Diabetes Association revised and updated the 6th Clinical Practice Guidelines in 2019. Targets of glycemic, blood pressure, and lipid control in type 2 diabetes mellitus (T2DM) were updated. The obese and overweight population is increasing steadily in Korea, and half of the Koreans with diabetes are obese. Evidence-based recommendations for weight-loss therapy for obesity management as treatment for hyperglycemia in T2DM were provided. In addition, evidence from large clinical studies assessing cardiovascular outcomes following the use of sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide 1 receptor agonists in patients with T2DM were incorporated into the recommendations. [ABSTRACT FROM AUTHOR]

Purpose: The efficacy of exclusive enteral nutrition (EEN) with a polymeric diet has not been confirmed in Korean pediatric patients with Crohn's disease (CD). This study aimed to compare the effectiveness of EEN with a specific polymeric diet (Encover®) and corticosteroids (CSs) for the induction of remission in Korean pediatric CD patients. Methods: We retrospectively compared data from 51 pediatric CD patients who underwent induction therapy with EEN (n=19) or CSs (n=32) at Severance Children's Hospital or Incheon St. Mary's Hospital in Korea. The primary endpoint of this study was the rate of clinical remission, defined as a Pediatric Crohn's Disease Activity Index (PCDAI) score <10, after 8 weeks of induction treatment. Clinical, laboratory, and growth data at post-induction as well as their changes from baseline were also compared between groups. Results: After 8 weeks of induction therapy, clinical remission rates were 78.9% (15/19) and 65.6% (21/32) in the EEN and CS groups, respectively (p=0.313). No significant differences in PCDAI scores, laboratory variables, and growth parameters were noted between the two groups at post-induction. However, significant changes in albumin levels at post-induction were observed in the EEN group compared to the CS group (p=0.038). Conclusion: Our results suggest that the effectiveness of EEN with a polymeric diet and CSs for induction therapy did not differ in Korean pediatric CD patients. EEN with a polymeric diet is a good first-line treatment option for the induction of remission in these patients. [ABSTRACT FROM AUTHOR]

The prevalence of gastroesophageal reflux disease (GERD) is increasing in Korea, and physicians, including surgeons, have been focusing on its treatment. Indeed, in Korea, medical treatment using a proton pump inhibitor is the mainstream treatment for GERD, while awareness of surgical treatment is limited. Accordingly, to promote the understanding of surgical treatment for GERD, the Korean Anti-Reflux Surgery Study Group published the Evidence-Based Practice Guideline for the Surgical Treatment of GERD. The guideline consists of 2 sections: fundamental information such as the definition, symptoms, and diagnostic tools of GERD and a recommendation statement about its surgical treatment. The recommendations presented 5 debates regarding fundoplication: 1) comparison of the effectiveness of medical and surgical treatments, 2) effectiveness of surgical treatment in cases of refractory GERD, 3) effectiveness of surgical treatment of extraesophageal symptoms, 4) comparison of effectiveness between total and partial fundoplication, and 5) effectiveness of fundoplication in cases of hiatal hernia. The present guideline is the first to demonstrate the efficacy of the surgical treatment GERD in Korea. [ABSTRACT FROM AUTHOR]

There have been few studies on the association between vitamin D levels and gastric cancer in Asian populations, but no studies have been performed on the interactions between vitamin D intake and polymorphisms in the vitamin D pathway. The effects of vitamin D intake, vitamin D related genetic polymorphisms, and their association with the incidence of gastric cancer were investigated in a hospital case-control study, including 715 pairs of newly diagnosed gastric cancer patients and controls matched for age and sex. Correlations between vitamin D intake and plasma vitamin D concentrations were also assessed in a subset of subjects. No statistically significant difference was observed in the dietary intake of vitamin D between the patients and controls, nor were there any evident associations between vitamin D intake and risk of gastric cancer in multivariate analyses. Vitamin D intake significantly correlated with the circulating 25-hydroxyvitamin D levels, but not with the active form of the vitamin, 1,25-dihydroxyvitamin D. There were no statistically significant interactions between vitamin D intake, and VDR or TXNIP polymorphisms. This study suggests that dietary vitamin D intake is not associated with gastric cancer risk, and the genetic polymorphisms of vitamin D-related genes do not modulate the effect of vitamin D with respect to gastric carcinogenesis. [ABSTRACT FROM AUTHOR]

The article offers the author's insight on his career in Korean Science, Technology and Society (STS) community that include teachin, engaging and exploring the potentials of STS in East Asia, which is based on his keynote speech given at the 12th East Asian STS Network Conference in Beijing, China in November 2016. He discussed topics including his involvement with History and Philosophy of Science (HPS) to STS, his educational and career history, and the history of STS in South Korea.

Purpose: Portland cement contains carcinogens such as chromium and free silica, and hence, inhalation of cement dust can cause respiratory tract cancers. The purpose of this study was to determine whether living near a cement plant increases the risk of respiratory tract cancers. Methods: The study population consisted of 341,793 people, all of whom lived in administrative districts within 3-km radius of ten cement plants in Korea. The respiratory tract cancer incidence data (International Classification of Diseases, ten revision code C00-C14 and C30-C34) for 2008-2012 were obtained from regional cancer registries. Standardized incidence ratios (SIRs) for each cancer site in the respiratory tract were calculated using an indirect standardization method. Results: Compared with the general Korean population, the incidence of lung and bronchus cancer (C33-C34) was significantly higher in all subjects [SIR 1.15, 95% confidence interval (CI) 1.02-1.29] and especially in the men subjects (SIR 1.47, 95% CI 1.29-1.68) in our study population. In addition, the incidence of larynx cancer in men (SIR 1.64, 95% CI 0.97-2.59) and salivary gland cancer in women (SIR 3.03, 95% CI 0.98-7.07) living near cement plants was marginally increased. Conclusions: These results suggest that environmental exposure to Portland cement dust is a risk factor for respiratory tract cancers. [ABSTRACT FROM AUTHOR]

The accurate mapping and assessment of groundwater vulnerability index are crucial for the preservation of groundwater resources from the possible contamination. In this research, novel intelligent predictive Machine Learning (ML) regression models of k-Neighborhood (KNN), ensemble Extremely Randomized Trees (ERT), and ensemble Bagging regression (BA) at two levels of modeling were utilized to improve DRASTIC-LU model in the Miryang aquifer located in South Korea. The predicted outputs from level 1 (KNN and ERT models) were used as inputs for ensemble bagging (BA) in level 2. The predictive groundwater pollution vulnerability index (GPVI), derived from DRASTIC-LU model was adjusted by NO 3 –N data and was utilized as the target data of the ML models. Hyperparameters for all models were tuned using a Grid Searching approach to determine the best effective model structures. Various statistical metrics and graphical representations were used to evaluate the superior predictive performance among ML models. Ensemble BA model in level 2 was more precise than standalone KNN and ensemble ERT models in level 1 for predicting GPVI values. Furthermore, the ensemble BA model offered suitable outcomes for the unseen data that could subsequently prevent the overfitting issue in the testing phase. Therefore, ML modeling at two levels could be an excellent approach for the proactive management of groundwater resources against contamination. [Display omitted] • Prediction of accurate GPVI using novel ML models at two levels of modeling. • Selection of hyperparameter values of ML modeling using automated Grid Search cross-validation. • Increase of DRASTIC-LU model performance using KNN, ERT, and BA models. • BA (level 2) is the best ML model by statistical metrics, graphical data, and GPVI spatial maps. [ABSTRACT FROM AUTHOR]

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Background: The present study summarizes the 11-year laparoscopic gastric cancer surgery experience of a single institution in South Korea and evaluates the current trends of laparoscopic gastric cancer surgery through our experience.Methods: A total of 3000 minimally invasive gastric cancer surgeries were performed at Seoul National University Bundang Hospital between May 2003 and January 2014. The types of laparoscopic gastrectomy used, surgical techniques, postoperative morbidities, and long-term oncologic outcomes were analyzed.Results: The proportion of challenging procedures such as laparoscopic total gastrectomy and laparoscopic gastrectomy for patients with advanced gastric cancer increased during the study period. The frequency of laparoscopic function-preserving gastrectomy for patients with early-stage cancer also increased. The overall rate of complications was 16.7 %; surgical and systemic complication rates were 11.8 and 6.2 %, respectively. There was one case of postoperative mortality due to delayed bleeding after discharge. Male gender, high BMI, long operating times, combined resection of other organs, and total and proximal gastrectomies were independent predictors of surgical morbidities; however, pathologic T-stage was not a predictable factor. Accumulated experience in laparoscopic surgery decreased the surgical complication rates of total and proximal gastrectomies more than it did in distal gastrectomy over time. The 5-year overall survival rates of patients in advanced stages and those who underwent laparoscopic total gastrectomy were comparable to those reported previously.Conclusions: Our results indicate the trends toward the expansion of laparoscopic approaches to technically demanding procedures and an increased use of laparoscopic function-preserving surgeries for patients with EGC with acceptable outcomes. [ABSTRACT FROM AUTHOR]

The deployment of renewable energy is considered as one of the important alternative solutions for reducing greenhouse gas emissions caused by electricity generation. As one of the key measures for promoting the deployment of renewable energy, the Renewable Portfolio Standard (RPS), which obligates power operators with a power equipment capacity of 500 MW or larger (excluding renewable energy equipment) to supply over a specific portion of their total electricity generation output in the form of renewable energy, was enacted in South Korea in 2012. However, there are still many disputes concerning the appropriate renewable energy deployment goal and the optimum portfolio for each renewable energy source which enable to minimize the economic burden while achieving the deployment target. Therefore, this paper intends to deduce the optimum portfolio up to 2050 based on explicit representation of renewable energy technologies and analyze the cost effect using the bottom–up energy system analysis model of electricity generation sector in South Korea. The result indicates that the potential for a reduction of the cost of PV was the highest and that, in the long term, it would account for the highest portion of the renewable energy portfolio as it was the most cost competitive technology. The additional cost for increasing the renewable deployment target 20% compared with the 3rd Energy Basic Plan was predicted to be between 107 and 115 USD/MW h. Therefore the renewable energy will be able to play a greater role in reducing GHG emission if the R&D to reduce investment and operation cost of PV and wind power is conducted successfully. [ABSTRACT FROM AUTHOR]

Information technology (IT) outsourcing is often used as a cost-saving strategy for firms. In IT outsourcing, the choice of vendor is a key factor determining success. This study examines the impact that the choice of IT vendor has on firms' IT outsourcing in Korea. The authors empirically analyzed the impact of certain characteristics of IT vendors on the market value of client firms in Korea using the event study methodology. First, the authors found that IT outsourcing announcements significantly increased the market value of firms. The authors also found that the market response to high asset-specific services of the IT vendor was significantly greater than the response to low asset-specific services. The authors' results also showed that the effect of Korean vendors was greater than that of foreign vendors. However, the difference between IT outsourcing to large vendors and small vendors in Korea was not significant, in contrast to the US. The information provided in this study can be used by client firms to select better IT vendors and by IT vendors to develop strategies to survive the rapidly changing IT outsourcing market in Korea. [ABSTRACT FROM AUTHOR]

ABSTRACT Background and aim: The objective of this paper is to evaluate the workload of staff in anatomic pathology (AP) laboratories in Korea. Methods: A survey was conducted at 197 AP laboratories in South Korea, these were categorized as 37 free standing laboratories, 14 laboratories in non-training hospitals (without residents), 79 in training hospitals (with residents), and 67 in university hospitals. The workloads of the staff were analyzed using the mean and standard deviation of the number of cases. Results: In total, there were 512 pathologists, 806 technicians and 205 cytopathology screeners. In a year, they processed a total of 3,150,261 histopathology cases and 4,115,420 cytopathology cases. The numbers of histopathology cases per pathologist or technician in one laboratory were 6,950 ± 6,748 and 4,074 ± 3,630, respectively. There were 109 laboratories that employed 205 cytoscreeners in addition to the 308 pathologists, where a cytoscreener read 14,780 ± 13,110 cases of cytopathology. However, in 88 laboratories, there were 132 pathologists who were not assisted by cytoscreeners, where a pathologist was reading 4,277 ± 3,033 cases of cytopathology. Conclusion: We propose a mean plus a standard deviation as a recommended guideline for staff workload at each laboratory setting to be used for a quality assurance program. [ABSTRACT FROM AUTHOR]

Urban forests have various environmental benefits that contribute to the quality of urban life. These values, however, have been underestimated or have never been reflected in urban development planning in Korea. As a result, a number of forests in urban areas were either partly or wholly destroyed without their public's value being assessed explicitly. The objective of this paper is to estimate the value attached by the public to Kwanggyo Mountain in the Seoul Metropolitan Area of Korea using a contingent valuation survey, aimed at providing policy-makers with useful information to make an informed public decision in urban development planning. The survey was carefully designed and implemented to meet a number of recommendation rules suggested in the literature. The overall results show that the respondents received the hypothetical scenario well and would be willing to pay a significant amount for the proposed programme of conserving the mountain. The total value stated by the public amounted to approximately 3.77 billion Korean won (US$2.9 million) per year. This quantitative information can be used in policy-making process for urban development plans. [ABSTRACT FROM AUTHOR]

High concentration of particulate matter (PM) threatens public health and the environment. Increasing traffic in the city is one of the main factors for increased PM in the air. Urban green spaces play an important role in reducing PM. In this study, the leaf surface and in-wax PM (sPM and wPM) accumulation were compared for 11 plant species widely used for landscaping in South Korea. In addition, biochemical characteristics of leaves (ascorbic acid chlorophyll content, leaf pH, and relative water content) were analyzed to determine air pollution tolerance. Plant species suitable for air quality improvement were selected based on their air pollution tolerance index (APTI) and anticipated performance index (API). Results showed a significant difference according to the accumulation of sPM and wPM and the plant species. PM accumulation and APTI showed a positive correlation. Pinus strobus showed the highest PM accumulation and APTI values, while Cercis chinensis showed the lowest. In 11 plants, API was divided into five groups. Pinus densiflora was classified as the best group, while Cornus officinalis and Ligustrum obtusifolium were classified as not recommended. [ABSTRACT FROM AUTHOR]

The enhanced assessment of groundwater contamination vulnerability is necessary for the management and conservation of groundwater resources because groundwater contamination has been much increased continuously in the world by anthropogenic origin. The purpose of this study is to determine the best model among three ANFIS-MOA models (the adaptive neuro-fuzzy inference system (ANFIS) combined with metaheuristic optimization algorithms (MOAs) such as genetic algorithm (GA), differential evolution algorithm (DE) and particle swarm optimization (PSO)) in assessing groundwater contamination vulnerability at a nitrate contaminated area. The Miryang City of South Korea was selected as the study area because the nitrate contamination was widespread in the city with two functions of urban and rural activities. Eight parameters (depth to water, net recharge, topographic slope, aquifer type, impact to vadose zone, hydraulic conductivity and landuse) were classified into the numerical ratings on basis of modified DRASTIC method (MDM) for the input variables of ANFIS-MOA models. The Original ANFIS, and 3 combined models of ANFIS-PSO, ANFIS-DE and, ANFIS-GA used 95 adjusted vulnerability indices (AVI) as the target data of training (70% data) and testing (30% data) processing. The performance of 4 models was evaluated by mean absolute errors (MAE), root mean square errors (RMSE), correlation coefficients (R), ROC/AUC curves and predicted AVI (PAVI) maps. The statistical results, spatial vulnerability maps and correlation coefficients between PAVIs and nitrate concentrations revealed that the order of model excellence was ANFIS-PSO, ANFIS-DE, ANFIS-GA, and Original ANFIS, and that ANFIS-PSO showed the highest performance in training and testing processing. The performance rates of ANFIS-MOA models were also compared with 10 recent popular worldwide models using the correlation coefficients between PVI and nitrate concentrations, and they were superior to other recent popular models. ANFIS-MOA models were also useful for resolving the subjectivity of physical and hydrogeological parameters in original DRASTIC method (ODM) and MDM. It is expected that ANFIS-PSO models will produce the excellent results in assessing groundwater contamination vulnerability and that they can greatly contribute to the groundwater security in other areas of the world as well as Miryang City of South Korea. [Display omitted] • Determine the best model in assessing groundwater contamination vulnerability. • Study area was Miryang City of South Korea due to heavy nitrate contamination. • Use ANFIS models with metaheuristic optimization algorithms of GA, DE and PSO. • Evaluate the model performance using MAE, RMSE, R, ROC/AUC and AVI maps. • ANFIS-PSO model was the best in the assessment of groundwater contamination vulnerability. [ABSTRACT FROM AUTHOR]

The author looks at the status of glycemic control in South Korea. He provides an overview of the prevalence of diabetes in the country. He mentions studies that demonstrate the role of an adequate glycemic control in preventing diabetic complication. The author also offers suggestions for improving glycemic control and reducing diabetic complications such as completing medical evaluation in all diabetic patients.

The scope of hydrogen energy is being extended in the Republic of Korea as a national innovative growth engine to overcome environmental problems, particularly climate change. The effects of this expansion on the energy system and national greenhouse gas (GHG) emissions are expected to vary greatly depending on the hydrogen energy supply chain scenario. Accordingly, in this study, the energy and environmental effects of hydrogen energy supply chain scenarios on the national energy system were analyzed quantitatively using the TIMES model, a representative bottom-up energy system analysis model. The scenarios were defined in terms of three perspectives: the development level of key technologies, contribution of future renewable energy to the power generation sector, and relative importance of each hydrogen production method portfolio. All scenarios were based on the policies being considered by the Korean government. The results of the scenario analyses show, among others, that green hydrogen, i.e., water electrolysis-oriented hydrogen production, consumes a fairly large amount of electricity. Therefore, from the perspective of the entire national energy system, the transition of the power sector to renewable energy, mainly solar and wind energies, and the advancement of water electrolysis are required to reduce the national GHG emissions. • Hydrogen energy supply chain can affect the national energy mix and emissions. • A bottom-up energy system model provides quantitative analysis. • Green hydrogen can substantially increase electricity consumption. [ABSTRACT FROM AUTHOR]

The recent advance of computational and interpretational algorithms is useful for developing an accurate prediction of the spatial distribution of groundwater-contamination vulnerability. Classical DRASTIC model of Aller et al. (1987) has been the most widely used for aquifer vulnerability mapping with seven hydrogeological parameters. Despite of its popularity, this technique disregards the effect of regional characteristics and the objective selection of the model parameters. It doesn't have a specific calibration function to secure its accuracy. The main goal of this research is to implement a calibration technique using optimization artificial neural network algorithm to obtain the more reliable and accurate assessment. The nonlinear optimization problem was solved by using Levenberg-Marquardt method to reduce the error between the vulnerability index and actual NO3-N concentration, and to maximize the correlation between them. The method was instigated to ANN model for an accurate prediction of the spatial distribution of groundwater-contamination vulnerability in the Miryang City, South Korea. This result showed that hydraulic conductivity, impact of vadose zone and land use are the most important predictors affecting the distribution of NO3-N concentration in the study area. The calibration model showed the better performance result (r=0.64) in compare with an un-calibrating modified DARSTIC model (r=0.28) The calibrated vulnerability map showed the high vulnerability near the Nakdong river including the extensive agricultural activity. We concluded that ANN model attained the better performance and reliability in assessing the groundwater-contamination vulnerability using the nonlinear function to reduce the linearity of the modified DARSTIC model in the study area. [ABSTRACT FROM AUTHOR]

This study measured the R&D outcomes of Korea's firms by analyzing the changes and patterns of technology knowledge flows and tried to see whether the outcomes of ICT R&D were better than those of non-ICT R&D. Using the registered patent data from 2008 and 2009, the authors computed the technology cycle time (TCT) and various centrality indexes with social network analysis (SNA), a popular method in patent citation analyses (PCA). In particular, the authors developed a technology spillover network and industry absorption network for the SNA. Having done these analyses, this study additionally conducted a confirmatory statistical test to compare ICT R&D with non-ICT R&D in terms of their performances. The authors found that Korea's ICT R&D has achieved higher levels of technology development speed, technology spillover and industry absorption when compared to non-ICT segments. The authors were also able to determine which particular ICT R&D is in an important position in terms of technology knowledge flows. [ABSTRACT FROM AUTHOR]

The article offers information on the 7th Aseanian Membrane Society Conference (AMS), which was held on July 4-7, 2012 in Busan, South Korea. The conference was hosted by the Membrane Society of Korea and more than 550 researchers participated in the event, presenting 400 scientific papers in the field of membrane science and technology.

The importance of achieving carbon neutrality by 2050 to combat climate change is widely recognized, leading to the proposal of various net-zero scenarios using energy system models. In these scenarios, hydrogen energy is often considered as a primary mitigation option alongside renewables. However, uncertainties surrounding hydrogen technologies prevent a comprehensive analysis of its role in achieving carbon neutrality. This study focuses on examining the impact of hydrogen energy demand, supply methods, and technology levels on carbon neutrality in the Republic of Korea using an energy system model. Findings suggest that hydrogen energy could constitute a significant portion of energy supply and demand by 2050. Sensitivity analyses reveal that reducing hydrogen imports could increase domestic power demand, while improving electrolysis efficiency could lead to more efficient carbon neutrality. Additionally, employing carbon capture technologies in hydrogen production rather than power generation is deemed effective. In conclusion, while hydrogen is a main reduction option for carbon neutrality, the effective utilization of hydrogen requires an increased reliance on imported hydrogen, further technology development including improved electrolysis efficiency and increased dissemination of reforming technologies with carbon capture, and the establishment of appropriate utilization strategies. • This study analyzes the role of hydrogen in carbon neutrality. • Hydrogen enables carbon-free power supply and counteracts volatility of renewables. • Hydrogen-to-power and power-to-hydrogen structure risks loss of efficiency. • Key measures: hydrogen trading, high efficiency electrolysis, reforming with carbon capture. [ABSTRACT FROM AUTHOR]

In December 2007, the Hebei Spirit oil spill occurred on the west coast of South Korea. Association between crude oil exposure and the levels of urinary oxidative stress biomarkers was reported among the local residents, 1.5 years after the accident. The aim of this study was to follow-up possible longer-term effects of the oil spill among the residents near the oil spill. Six years after the accident, urinary oxidative stress biomarkers of the residents were associated with surrogates of oil exposure. The target subjects were divided into two groups based on the distance of their residence to the spill site, i.e., those near the spill site (‘Near’ group, n = 476), and those far from the spill (‘Far’ group, n = 152). A questionnaire was administered by trained interviewers or self-reporting, and demographic information and other parameters of the participants, such as socioeconomic status, smoking and drinking behaviors, disease history, and duration of clean-up activities after the spill, were collected. The participants' levels of 8–hydroxy–2–deoxyguanosine (8–OHdG) and malondialdehyde (MDA) in 12 h urine samples were measured as indicators of oxidative DNA damage and lipid peroxidation, respectively. A general linear model was used for statistical analysis. Urinary MDA and 8-OHdG levels measured from ‘Near’ group, i.e., geometric mean of 2.19 μmol/g creatinine, and 5.41 μg/g creatinine, respectively, were higher than those of ‘Far’ group. Especially, urinary 8-OHdG levels in the ‘Near’ group were significantly higher than those of ‘Far’ after adjusting relevant covariates. In addition, the duration of clean–up activities showed a significant association with both urinary 8–OHdG and MDA levels. Even 6 years after the oil spill, positive associations between oxidative stress biomarkers and surrogates of oil exposure were evident. While the present study design lacks biomarkers of exposure, the results of this study suggest that the consequences of oil pollution may last for years. [ABSTRACT FROM AUTHOR]