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Background: The use of beta-tricalcium phosphate (beta-TCP) in dental surgery is limited owing to its rapid absorption compared to mixed formulations of hydroxyapatite. However, newly developed pure beta-TCP crystals have demonstrated slow absorption; hence, they last longer within the defect and act as a scaffold until new bone formation. The oral environment is unique and can prove unfavorable for bone grafts due to the high infection rate in the oral cavity and the fragile condition of the oral mucosa. The aim of this study was to evaluate the feasibility of using pure beta-TCP bone grafts in various dental treatments. Methods: Panoramic X-ray images of 25 patients who underwent bone grafting during dental surgery were analyzed. A specially treated pure beta-TCP crystal, Neo Bone® (Neo Bone®, SN Biologics Co., Ltd, Seoul, Korea), was used in this study. The bone density at the graft site was compared with that of the surrounding bone using the ImageJ software (Wayne Rasband, NIH USA). Results: Six months after surgery, the bone graft density was similar to that of the surrounding bone in 20 patients and increased in 5 patients. No adverse effects, such as infection, dehiscence, or graft failure, were observed. Conclusion: The newly developed pure beta-TCP crystal was slowly absorbed and served as support until new bone formation at the defect site, thus demonstrating its potential for use in various oral conditions requiring bone grafting. [ABSTRACT FROM AUTHOR]

Purpose: Whether prior radiotherapy (RT) affects the response of EGFR-mutated non-small cell lung cancer (NSCLC) to EGFR tyrosine kinase inhibitor (TKI) remains elusive. Methods: Patients with EGFR-mutated NSCLC treated with EGFR TKIs who recurred after curative treatment at Asan Medical Center, Seoul, Korea were included. The progression-free survival (PFS) and overall survival (OS) from the initiation of EGFR TKI in patients who recurred after definitive RT were analyzed and compared to the outcomes of RT-naïve patients with advanced NSCLC treated with EGFR TKIs from previously reported prospective clinical trial results. Results: A total of 60 patients who recurred after definitive RT were included. The median age was 70 years (range, 38–88), with 24 patients (40.0%) being males. Among the 60 patients, 52 patients (86.7%) had exon 19 deletion or L858R mutation, with 49 patients (81.7%) receiving gefitinib as the first-line EGFR TKI. The median PFS and OS from the initiation of EGFR TKI were 10.4 months (95% confidence interval [CI], 7.4–13.2) and 21.3 months (95% CI, 13.4–28.8), respectively. Conclusion: The EGFR TKI efficacy in EGFR-mutated patients with NSCLC who recurred after RT was comparable with that in historic controls of RT-naïve patients with advanced NSCLC treated with EGFR TKIs, indicating that RT may not affect EGFR TKI efficacy. [ABSTRACT FROM AUTHOR]

Background: Osteomyelitis (OM) in the jaw is an inflammatory disease of osseous tissue that begins in the medullary space and progressively expands to the cortical portion of the bone, the Haversian system, the periosteum and the overlying soft tissue. Despite advances in dental and medical care, OM persists and is of important concern in modern medicine. Active negative pressure is known to prevent post-operative hematoma; decrease the number of bacterial pathogens, accumulation of toxins, and necrotic tissue; and promote osteogenesis and angiogenesis with the use of a draining tube such as the Jackson-Pratt (JP) or Hemovac. The purpose of this study was to assess the effectiveness of decompression for the treatment of OM in the jaw.Methods: This retrospective study included a total of 130 patients, 55 patients with sclerosing OM and 75 patients with suppurative OM were included. The radiographic bone densities expressed as a grayscale values (GSVs), were measured using an easy digitalized panoramic analysis (EDPA) method, processed on the conditional inference tree, generated by the R program® 3.2.3 with a probability of 96.8%. Rectangle annotation analysis of INFINITT PACS® (INFINITT Healthcare, Seoul, Korea) of 50 mm2 was determined as the region of interest (ROI). Student's t-test and ANOVA were used to determine significance (p < 0.05).Results: Significant changes was observed between radiographic bone density in the sclerosing type with drain and without drain at the six-month and one-year follow-up (p < 0.05). Significant difference was demonstrated between the suppurative OM with drain and without drain groups at the one-year follow-up (p < 0.05).Conclusion: The OM groups with drain exhibited more enhanced bone density compared to the groups without drain at the six-month and one-year follow-ups. The drain insertion for decompression is effective for the management of sclerosing and suppurative OM. It is recommended to implement it for the management of OM. [ABSTRACT FROM AUTHOR]

Background: An emerging body of literature has indicated that moderate alcohol intake may be protective against Alzheimer disease (AD) dementia. However, little information is available regarding whether moderate alcohol intake is related to reductions in amyloid-beta (Aβ) deposition, or is protective via amyloid-independent mechanisms in the living human brain. Here we examined the associations of moderate alcohol intake with in vivo AD pathologies, including cerebral Aβ deposition, neurodegeneration of AD-signature regions, and cerebral white matter hyperintensities (WMHs) in the living human brain.Methods and Findings: The present study was part of the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer's Disease (KBASE), an ongoing prospective cohort study that started in 2014. As of November 2016, 414 community-dwelling individuals with neither dementia nor alcohol-related disorders (280 cognitively normal [CN] individuals and 134 individuals with mild cognitive impairment [MCI]) between 56 and 90 years of age (mean age 70.9 years ± standard deviation 7.8; male, n [%] = 180 [43.5]) were recruited from 4 sites (i.e., 2 university hospitals and 2 public centers for dementia prevention and management) around Seoul, South Korea. All the participants underwent comprehensive clinical assessments comprising lifetime and current histories of alcohol intake and multimodal brain imaging, including [11C] Pittsburgh compound B positron emission tomography (PET), [18F] fluorodeoxyglucose (FDG) PET, and magnetic resonance imaging (MRI) scans. Lifetime and current alcohol intake were categorized as follows: no drinking, <1 standard drink (SD)/week, 1-13 SDs/week, and 14+ SDs/week. A moderate lifetime alcohol intake (1-13 SDs/week) was significantly associated with a lower Aβ positivity rate compared to the no drinking group, even after controlling for potential confounders (odds ratio 0.341, 95% confidence interval 0.163-0.714, p = 0.004). In contrast, current alcohol intake was not associated with amyloid deposition. Additionally, alcohol intake was not related to neurodegeneration of AD-signature regions or cerebral WMH volume. The present study had some limitations in that it had a cross-sectional design and depended on retrospective recall for alcohol drinking history.Conclusions: In this study, we observed in middle- and old-aged individuals with neither dementia nor alcohol-related disorders that moderate lifetime alcohol intake was associated with lower cerebral Aβ deposition compared to a lifetime history of not drinking. Moderate lifetime alcohol intake may have a beneficial influence on AD by reducing pathological amyloid deposition rather than amyloid-independent neurodegeneration or cerebrovascular injury. [ABSTRACT FROM AUTHOR]

A right liver graft with middle hepatic vein (MHV) reconstruction is the standard graft for adult-to-adult living donor liver transplantation (LDLT). The patency of reconstructed MHV affects the recovery and regeneration of graft. The aim of the study is to evaluate the patency rate of reconstructed MHV according to the reconstruction material in LDLT using the right liver. The data was collected retrospectively on 521 patients who underwent LDLT with right liver graft form August 2003 to December 2012 at the Seoul St. Mary's Hospital in Seoul. Two serial comparisons were performed. At first, patients were divided into 2 groups: biologic graft group (n = 252) and synthetic graft group (n = 177). Second, patients were divided into 6 groups: No MHV reconstruction (n = 92); MHV was reconstructed by greater saphenous vein (GSV) (n = 20); recipient's portal vein (PV) (n = 219); cryopreserved iliac artery (CIA) (n = 2); cryopreserved iliac vein (CIV) (n = 11); polytetrafluoroethylene (PTFE) graft (n = 105); and polyethylene terephthalate (PETE) graft (n = 72). We compared the patency of reconstructed MHV among these groups by computed tomography angiography at 7 days, 20 days, 90 days, and 1 year. At the first comparison, the patency rate of the biologic graft group on the seventh postoperative day was 61.9%, and the synthetic graft group was 72.4% (P =.029). At postoperative 1 year, the patency rate of the biologic graft group was 42.9%, and the synthetic graft group was 24.1% (P =.001). At the second comparison, the MHV patency of GSV, PV, CIA, CIV, PTFE, and PETE was 65.0%, 62.5%, 50%, 63.6%, 75%, 72% on the seventh postoperative days (P =.318); 60%, 57.1%, 50%, 54.5%, 69%, 55.6% on the 20th postoperative days (P =.444); 40%, 48.8%, 50%, 27.3%, 47%, 34.1% on the 90th postoperative days (P =.294); and 30%, 45.2%, 50%, 27.3%, 27%, 26.4% at 1 postoperative year (P =.008). Although there was no statistical difference in comparison of each material, there were significant differences in MHV patency rates between the biologic and the synthetic group. Therefore, the synthetic graft could be considered in living donor liver transplantation with MHV reconstruction. [ABSTRACT FROM AUTHOR]

This study was designed to evaluate the dimensions of the bony cochlear nerve canal (BCNC) in congenital unilateral sensorineural hearing loss (USNHL) patients with normal inner ears, and to analyze the correlation between BCNC and hearing status. Medical records and temporal bone computed tomography (TBCT) findings of 380 patients who visited Seoul National University Hospital between January 1999 and December 2007 were reviewed retrospectively. The length and width of the BCNC at the fundus of the internal auditory canal were measured in millimeters based on the axial view of TBCT for three ear groups: normal inner ears of control group subjects (group A, 179 ears), normal inner ears on the contralateral side of USNHL patients (group B, 201 ears), and the affected inner ears in USNHL (group C, 201 ears). The mean values of length and width in group C (0.79 ± 0.36 and 1.58 ± 0.83 mm, respectively) were significantly smaller than those in group A (1.07 ± 0.10 and 2.38 ± 0.28 mm, respectively; p < 0.001) and group B (1.04 ± 0.23 and 2.33 ± 0.39 mm, respectively; p < 0.001). The receiver operating characteristic curves for BCNC were conducted to estimate the cutoff values from which the proportions of profound hearing loss increased, compared to those of mild to severe hearing loss. The areas under the curve were 0.487 ± 0.044 (p = 0.781) and 0.622 ± 0.041 (p = 0.011) for length and width, respectively. The cutoff value of width with a sensitivity of 90% for profound USNHL was 1.16 mm in otherwise normal inner ears. Clinicians would be recommended to take a close look at BCNC as one of the possible causes of hearing loss in otherwise normal inner ears of USNHL on TBCT. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

STSAT3, a ∼150-kg micro-satellite, is the third experimental micro-satellite of the STSAT (Science Technology Satellite) series designated for the Long-Term Plan for Korea's Space Development by the Ministry of Education, Science and Technology of Korea. A Compact Imaging Spectrometer (COMIS) for use in the STSAT3 micro-satellite is currently under construction. It is scheduled to be launched into a low sun-synchronous Earth orbit (∼700 km) by the end of 2012. COMIS was inspired by the success of Compact High Resolution Imaging Spectrometer (CHRIS), a small hyperspectral imager developed for the European Space Agency (ESA) micro-satellite Project for On Board Autonomy (PROBA). COMIS, as its name implies, is very compact in terms of volume, mass and power. The total mass including the optics, housing and electronics is approximately 4.3 kg, and the average operational power is less than 13 W. Its main operational goal will be the imaging of the Earth's surface and atmosphere with ground sampling distances of 27 m at the 18-62 spectral bands (0.4-1.05 μm). COMIS takes hyperspectral images in two different modes: strip imaging and stereo viewing observation. This imaging will be used for environmental monitoring, such as the inland water quality monitoring of Paldang Lake, which is located close to Seoul, South Korea. [ABSTRACT FROM AUTHOR]

Foodborne disease (FBD) is a common food safety problem in Seoul, Republic of Korea. To identity target areas for improvement of the food safety programs, FBD outbreaks from 2002 to 2006 were analyzed with regard to facility, monthly occurrences, and causative agents. A total of 147 FBD outbreaks were reported, with an average of 29.4 FBD outbreaks per year and 49 cases per outbreak. Restaurants and school lunches were two main facilities associated with 76.2% of the outbreaks. A majority of FBD cases (73.1%) were from school lunches. The highest number of outbreaks and cases occurred in June, followed by March. Among the seven identified causative agents, norovirus was the most significant in the number of outbreaks and cases. Among the outbreaks and cases with causative agents identified, norovirus and Staphylococcus aureus were responsible for 61.7% of outbreaks and 81.5% of cases. The analysis indicates that the efficiency of current food safety programs could be enhanced if critical control points in school lunch programs are identified and incorporated in the training and inspection. Identifying risk factors for contamination of norovirus and Staphylococcus aureus would also be beneficial. [ABSTRACT FROM AUTHOR]

This paper deals with an accessibility analysis of Korean high-speed rail. The high-speed intercity service, which became operational in April 2004, has being creating positive impacts on forming a modal share structure conformable to the notion of the competitive advantage between travel modes. Patronage, however, is approximately half of that forecast. Accessibility improvement is generally accepted as one of the most urgent methods for increasing ridership. A systemized accessibility analysis with a case study of the Seoul metropolitan area is made. A reduced form of a Hansen-type accessibility measure is proposed. An analysis of variance (ANOVA) test and a Geographic Information Systems (GIS)-based mapping audit are used as tools for the assessment. Finally, zones of opportunity that could yield the greatest demand increase of high-speed rail are identified and some metropolitan railway expansions for improving accessibility of the region are recommended. [ABSTRACT FROM AUTHOR]

A defining characteristic of the urbanization is the transformation of existing pervious areas into impervious areas during development. This leads to numerous hydrologic and environmental problems such as an increase in surface runoff due to excess rainfall, flooding, the deterioration of water quality, and an increase in nonpoint source pollution. Several studies propose supplementary measures on environmental change problems in development areas using the low impact development technique. This study investigated the reduction of nonpoint source pollutant loads and flooding in catchments through urban catchment rainfall–runoff management. For the quantitative assessment of flood disasters and water pollution problems, we propose a reliability evaluation technique. This technique refers to a series of analysis methods that determine the disaster prevention performance of the existing systems. As the two factors involve physical quantities of different dimensions, a reliability evaluation technique was developed using the distance measure method. Using the storm water management model, multiple scenarios based on synthetic rainfall in the catchment of the Daerim 2 rainwater pumping station in Seoul, South Korea, were examined. Our results indicate the need for efficient management of natural disaster risks that may occur in urban catchments. Moreover, this study can be used as a primary reference for setting a significant reduction target and facilitating accurate decision making concerning urban drainage system management. [ABSTRACT FROM AUTHOR]

[Display omitted] The Sudokwon landfill (SL) in the Seoul metropolitan area, South Korea, is among the world's largest landfills, striving to curtail landfill gas (LFG) emissions and achieve carbon neutrality by 2050. Since 2005, the SL Management Corporation (SLC) has measured LFG emissions (i.e., methane (CH 4) and carbon dioxide (CO 2)) using a dynamic flux chamber proposed by the US EPA. However, uncertainty prevails in validating the reduction of LFG emissions due to the limited spatiotemporal data coverage. In 2020, an eddy covariance (EC) system was installed to enhance measurements, revealing highly fluctuating LFG emissions driven by waste layer LFG production, LFG collection, and atmospheric pressure changes. During the study period, the annual CH 4 emission increased slightly from 465.0 ± 4.2 to 485.5 ± 6.4 g C m−2, while that of CO 2 decreased by 2/3 (from 408.7 ± 16.5 to 270.6 ± 18.8 g C m−2), primarily due to the doubled CO 2 uptake by the vegetated topsoil. Our first long-term (March 2020 to February 2022) quasi-continuous monitoring using EC (with a gap-filling and partitioning technique based on Random Forest) emphasizes the difficulty of temporal upscaling of discontinuously observed surface emissions to quantify the LFG inventory and the need for continuous observations or suitable proxies (e.g., atmospheric CH 4 concentration). [ABSTRACT FROM AUTHOR]

Kidney transplants from living donors have increased, but few studies have examined the long-term risks of live donor nephrectomy. This is the first study to report the blood pressure (BP) changes associated with cardiovascular disease and linked to chronic kidney disease (CKD) 1 year after live donor nephrectomy. This study examined a prospective cohort of patients who underwent donor nephrectomy between March 1, 2006, and December 31, 2016, at the Severance Hospital, Seoul, South Korea. CKD was defined as a glomerular filtration rate (GFR) of < 60 mL/min/1.73m2. Patients with a history of hypertension or CKD or an estimated GFR < 60 mL/min/1.73m2 were excluded; those examined after 1 year post-nephrectomy were included in the study population. Among 420 patients who underwent donor nephrectomy, 137 (32.6%) developed a first-time onset of a GFR < 60 mL/min/1.73m2 by the first year after surgery. After propensity score–matching the age, systolic BP (P <.001) and pulse pressure (P =.006) were significantly associated with the groups with newly developed CKD. Systolic BP and pulse pressure decreased significantly at 1 year after donor nephrectomy. These differences decreased after donor nephrectomy, possibly lowering the risk of cardiovascular disease. • This study investigated the blood pressure changes—specifically systolic (SBP), diastolic (DBP), and pulse pressure (PP)—in living donors at 1 year postsurgery to identify the risk of developing cardiovascular or chronic kidney disease (CKD). • SBP and PP, which are associated with the risk of developing CKD, decreased 1 year post-surgery. • The improvement of SBP and PP stemmed from a program at our institution that maintained close contact with the living donors and taught them how to maintain a healthy lifestyle using nonpharmacologic methods. [ABSTRACT FROM AUTHOR]

• During 2017–2020, 15 RVA outbreaks occurred at neonatal facilities in Seoul, Korea. • Only two genotypes, G4P[6] and G8P[6], were detected in those neonatal outbreaks. • The novel G8P[6] RVA predominated since its emergence in 2018. • Continued surveillance for circulating RVA is needed to monitor genotype changes. Rotavirus group A (RVA) is a causative agent of acute gastroenteritis among young children worldwide, despite the global expansion of rotavirus vaccination. In Korea, although the prevalence of RVA has been reduced among young children owing to vaccination, nosocomial infections still occur among neonates. The aim of this study was to investigate the molecular epidemiology of RVA strains associated with several neonatal outbreaks in Seoul from 2017 to 2020. Clinical and environmental samples were collected and screened for the presence of RVA using ELISA and PCR targeting VP6, respectively. RVA-positive strains were genotyped via RT-PCR and subsequent sequencing of VP4 and VP7 and were phylogenetically compared with RVA strains from other countries. During 2017–2020, a total of 15 RVA outbreaks occurred at neonatal facilities (six in hospital neonatal wards and nine in postpartum care centers) in Seoul, and only two RVA genotypes were detected: G4P[6] and G8P[6]. G8P[6] emerged in Seoul November 2018 and immediately became the predominant genotype among neonates, at least up to 2020. Phylogenetic analysis revealed that the G8P[6] genotype in this study was closely related to G8P[6] strains first identified in Korea in 2017, but differed from G8P[6] strains detected in Africa. A novel G8P[6] genotype of RVA strains has emerged and caused outbreaks among neonates in Seoul. Continued surveillance for circulating RVA genotypes is imperative to monitor genotype changes and their potential risks to public health. [ABSTRACT FROM AUTHOR]

The rapid increase in carbapenemase-producing Enterobacterales is a global health concern. During 2017-2020, a total of 44 Escherichia coli isolates co-harbouring bla NDM-5 and bla OXA-181 were collected from patients at 17 hospitals in Seoul and characterized based on antimicrobial susceptibility, resistance genes and plasmid replicons detected using polymerase chain reaction (PCR). Clonal relatedness was estimated using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). All isolates had an identical multidrug resistance profile, including resistance to carbapenems, cephalosporins, ciprofloxacin, tetracycline, and trimethoprim/sulfamethoxazole, and susceptibility to amikacin, colistin, and tigecycline. Resistance genes (bla CTX-M-15 , bla CMY-2 , bla TEM-1B , bla OXA-1 , aac(6')-Ib-cr , and qnrS) and plasmid replicons (IncFIA, IncFIB, and IncX3) was observed in almost all isolates. All isolates belonged to ST410 and were genetically similar (>88% similarity), with some PFGE types shared among isolates from different hospitals. Analysis of the whole genome revealed that the isolates clustered together with other strains of the international high-risk clone ST410 B4/H24RxC from other countries. These findings underline the ongoing spread of the high-risk clone of NDM-5- and OXA-181-producing E. coli ST410 B4/H24RxC among hospitals in Seoul. Continuous monitoring and implementation of infection control measures are crucial to track and prevent further spread of these resistant strains. [ABSTRACT FROM AUTHOR]

• Carbapenem-resistant Enterobacterales (CRE) strains (n =3675) were collected in Seoul, Republic of Korea. • mcr genes (mcr-1, -4, -9 and -10) were detected in 2.2% (80/3675) of CRE strains. • Enterobacter cloacae complex strains (20.5%) were positive for mcr-9 or mcr-10. • mcr genes have been silently disseminating among CRE strains in Seoul. Colistin is often used as a drug of last resort against infections caused by multi-drug-resistant Gram-negative bacteria, including carbapenem-resistant Enterobacterales (CRE). Recently, the acquisition of mobile colistin resistance (mcr) genes by CRE has become a cause for concern. This study investigated the prevalence of mcr genes in CRE isolates in Seoul, Republic of Korea. In total, 3675 CRE strains were collected from patients between 2018 and 2019, and initially screened for mcr genes using multiplex polymerase chain reaction assays. Upon the identification of mcr -harbouring strains, colistin susceptibility tests, identification of carbapenemase and β-lactamase genes, and plasmid replicon typing were performed. Clonal analysis was conducted using pulsed-field gel electrophoresis. mcr genes were detected in 2.2% (80/3675) of CRE strains. There were three mcr-1 carriers, one mcr-4.3 carrier, one mcr-4.3 / mcr-9 carrier, 58 mcr-9 carriers, one mcr-9 / mcr-10 carrier and 16 mcr-10 carriers among various Enterobacterales species, of which 60 were Enterobacter cloacae complex (ECC) strains. The prevalence of mcr genes in ECC strains was 20.5%. Molecular detection confirmed that 21.3% and 13.8% of mcr -harbouring strains shared bla NDM-1 or bla KPC-2 , respectively. In addition, an IncHI2 replicon was identified in 71.7% of mcr-9 strains. Comparative analysis revealed not only a notable diversity of mcr carriers, but also clonal spreading or nosocomial outbreaks of some ECC strains. These findings revealed a silent distribution of mcr genes in CRE strains with high genetic heterogeneity in Seoul, underscoring the urgent need for timely intervention to control and prevent mcr dissemination. [ABSTRACT FROM AUTHOR]