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The Republic of Korea is characterized by its north-to-south stretch and high mountain ranges along the eastern coast, resulting in terrain with higher elevation in the east and lower in the west. These geographical features typically lead to regional climate differences, either based on latitude or from east to west. In the present study, for effectiveness, the entire Korean peninsula was divided into four regions based on the geographical features: The Northeast Coast (NEC), Central Inland (MI), Southeast Coast (SEC), and South Coast (SC). Two test sites were chosen from each region, except for the SC. The linear relationship between the altitude of sites and the mean oxygen isotope ratio (δ18O) revealed a negative correlation; the highest (1,447 m a.s.l.) and the lowest altitude (86 m a.s.l.) sites had a mean δ18O of 27.03‰ and 29.67‰, respectively. The sites selected from the same region exhibited stronger correlation coefficients (0.75–0.79) and Glk (Gleichläufigkeit) (74–83%) between the tree-ring oxygen isotope chronologies (δ18OTR chronologies) than those from different regions (0.60–0.69/70–79%). However, subtle variations in pattern were observed in the comparison period during a few selected intervals (approximately 10 years). All the regional δ18OTR chronologies exhibited positive correlations with either June or July temperatures over Korea, whereas negative correlations with regional summer precipitation and SPEI-3. Moreover, the chronologies showed notable negative correlations with the water condition of western Japan. The findings of this study can be used as a scientific reference for the study of variations of rainfall in East Asia using δ18OTR chronology.

Purpose The ultimate goal of current open access (OA) initiatives is for library services to use OA resources. This study aimed to assess the infrastructure for OA scholarly information services by tabulating the number and proportion of OA articles in a literature database. Methods We measured the absolute numbers and proportions of OA articles at different time points across various disciplines based on the Web of Science (WoS) database. Results The number (proportion) of available OA articles between 2000 and 2021 in the WoS database was 12 million (32.4%). The number (proportion) of indexed OA articles in 1 year was 0.15 million (14.6%) in 2000 and 1.5 million (48.0%) in 2021. The proportion of OA by subject categories in the cumulative data was the highest in the multidisciplinary category (2000–2021, 79%; 2021, 89%), high in natural sciences (2000–2021, 21%–46%; 2021, 41%–62%) and health and medicine (2000–2021, 37%–40%; 2021, 52%–60%), and low in social sciences and others (2000–2021, 23%–32%; 2021, 36%–44%), engineering (2000–2021, 17%–33%; 2021, 31%–39%) and humanities and arts (2000–2021, 11%–22%; 2021, 28%–38%). Conclusion Our study confirmed that increasingly many OA research papers have been published in the last 20 years, and the recent data show considerable promise for better services in the future. The proportions of OA articles differed among scholarly disciplines, and designing library services necessitates several considerations with regard to the customers’ demands, available OA resources, and strategic approaches to encourage the use of scholarly OA articles.

An anatomical understanding of the atrial myocardium is crucial for surgeons and interventionists who treat atrial arrhythmias. We reviewed the anatomy of the inter-nodal and intra-atrial conduction systems. The anterior inter-nodal route (#1) arises from the sinus node and runs through the ventral wall of the atrial chambers. The major branch of route #1 approaches the atrioventricular node from the anterior aspect. Other branches of route #1 are Bachmann’s bundle and a vestibular branch around the tricuspid valve. The middle inter-nodal route (#2) begins with a broad span of fibers at the sinus venarum and extends to the superior limbus of the oval fossa. The major branch of route #2 joins with the branch of route #1 at the anterior part of the atrioventricular node. The posterior inter-nodal route (#3) is at the terminal crest and gives rise to many branches at the pectinate muscles of the right atrium and then approaches the posterior atrioventricular node after joining with the vestibular branch of route #1. The branches of the left part of Bachmann’s bundle and the branches of the second inter-nodal route form a thin myocardial network at the posterior wall of the left atrium. These anatomical structures could be categorized into major routes and side branches. There are 9 or more anatomical circles in the atrial chambers that could be structural sites for macro re-entry. The implications of normal and abnormal structures of the myocardium for the pathogenesis and treatment of atrial arrhythmias are discussed.

Abstract We tested the feasibility of pulmonary vein (PV) and left atrial (LA) posterior wall isolation using non-invasive stereotactic ablative body radiotherapy (SABR) and investigated pathological changes in irradiated lesions in a canine model. Seven male Mongrel dogs received single-fraction 33 Gy SABR. We designed the en-bloc circular target of total PVs and LA posterior wall to avoid the esophagus. The circular box lesion included the LA roof and ridge, low posterior wall, and posterior interatrial septum. At 6 weeks or 4 months post-SABR, electrical isolation of the SABR lesion was confirmed using LA posterior wall pacing, and histopathological review was performed. Electrical isolation of all PVs and the LA posterior wall was achieved in three of five dogs in the 4-month group. There was one target failure and one sudden death at 15 weeks. Although two dogs in the 6-week group failed to achieve electrical lesion isolation, the irradiated atrial myocardium showed diffuse hemorrhage with inflammatory cell infiltration. In successfully isolated 4-month model dogs, we observed transmural fibrotic scarring with extensive fibrosis on irradiated atrial tissue. The findings suggest that this novel circular box-design radiotherapy technique using SABR could be applied to humans after further studies are conducted to confirm safety.

Abstract Subalpine conifers are highly sensitive to climatic changes. In these trees, the intra-annual dynamics of cambial activity and phenological process in xylem development are closely associated with climatic conditions. However, these scientific findings have not been verified for subalpine conifers in the Republic of Korea. Therefore, we initiated such a study with four subalpine conifers, viz. Abies koreana, Pinus koraiensis, Taxus cuspidata, and Picea jezoensis, growing between 1573 and 1594 m a.s.l. at Deogyusan National Park. Microcores (Ø 2 mm) of these trees were obtained using a mini borer, called as Trephor, every week between April 7 and September 25 in 2017 to monitor their growing seasons, the intra-annual dynamics of the cambial activity, and the number of cells during phenological phases of cell enlargement and cell-wall thickening. For the study, five trees were selected for each conifer species. Results showed that the cambial activity of A. koreana, P. koraiensis, and P. jezoensis required at least 73.8 heat-sum values, whereas the T. cuspidata needed 109.6 heat-sum. The durations of cambial activity of A. koreana, P. koraiensis, T. cuspidata, and P. jezoensis were 134 (127–144), 113 (92–128), 113 (106–120), and 100 (76–128) days, respectively. The intra-annual variations of the number of cells in the cambium, during the cell enlargement phase and cell-wall thickening phase showed predominantly a bell-shaped curve, with a delay of approximately 2–4 weeks between each other. On the other hand, the number of cumulated mature cells showed an S-shaped curve. Through this study, the first fundamental data on phenological process in xylem development of subalpine conifers in the Republic of Korea have been successfully presented.

The Rhododendron spp. (R. yedoense and R. mucronulatum) at high elevations of Mt. Halla in Jeju Island are the dominant species in the shrubland. Despite the recent damage to their growth due to climate change and the spread of Sasa spp., these species have not yet been studied systematically in Korea. Therefore, the current study aimed to verify the effect of abiotic factors, e.g., temperature and precipitation, and the spread of Sasa spp. as a neighbor species on their growth based on ring-width measurement data. In addition, the death years were dated using the cross-dating method developed in dendrochronology by comparing the individual ring-width time series from dead Rhododendron spp. with the corresponding chronology established using living trees. For the study, disk samples were obtained from 11 and 10 living R. yedoense and R. mucronulatum, respectively, to establish tree-ring time series. To investigate the death years, six disk samples were also collected from each shrub species. The relatively high occurrence of missing or discontinuous rings is a characteristic of shrubs, which makes tree-ring analysis difficult. Through cross-dating, it was verified that the R. mucronulatum and R. yedoense have 4.3% and 5.3% missing and/or discontinuous rings (the total number of missing and/or discontinuous rings/the total number of tree rings), respectively. All dead shrubs were successfully dated based on synchronization of the individual time series with the corresponding chronologies established using the cross-dated time series; nine shrubs died in the 2010s and the other two shrubs in 1996 and 2001, respectively. Most deaths occurred when Sasa quelpaertensis dominantly occupied the study sites. From the analysis of the relationships between the residual chronologies and the bioclimate predictors (BioClim), only R. mucronulatum showed reliable correlations with the Bio5 (maximum temperature of the warmest month) as +0.28 (p < 0.05) and the Bio18 (precipitation of warmest quarter) as −0.33 (p < 0.05). This result means that summer temperature is a limiting factor for the growth of R. mucronulatum. Through this study, it was verified that Rhododendron spp. at high elevations in Korea can be used for research using tree rings.

Background The definitive pathologic diagnosis of cardiac sarcoidosis requires observation of a granuloma in the myocardial tissue. It is common, however, to receive a “negative” report for a clinically probable case. We would like to advise pathologists and clinicians on how to interpret “negative” biopsies. Methods Our study samples were 27 endomyocardial biopsies from 25 patients, three cardiac transplantation and an autopsied heart with suspected cardiac sarcoidosis. Pathologic, radiologic, and clinical features were compared. Results The presence of micro-granulomas or increased histiocytic infiltration was always (6/6 or 100%) associated with fatty infiltration and confluent fibrosis, and they showed radiological features of sarcoidosis. Three of five cases (60%) with fatty change and confluent fibrosis were probable for cardiac sarcoidosis on radiology. When either confluent fibrosis or fatty change was present, one-third (3/9) were radiologically probable for cardiac sarcoidosis. We interpreted cases with micro-granuloma as positive for cardiac sarcoidosis (five of 25, 20%). Cases with both confluent fibrosis and fatty change were interpreted as probable for cardiac sarcoidosis (seven of 25, 28%). Another 13 cases, including eight cases with either confluent fibrosis or fatty change, were interpreted as low probability based on endomyocardial biopsy. Conclusions The presence of micro-granuloma could be an evidence for positive diagnosis of cardiac sarcoidosis. Presence of both confluent fibrosis and fatty change is necessary for probable cardiac sarcoidosis in the absence of granuloma. Either of confluent fibrosis or fatty change may be an indirect pathological evidence but they are interpreted as nonspecific findings.

Abstract The current study was initiated to test the synchronizations of tree-ring δ18O (hereafter δ18OTR) time series within and between tree species and provinces, which are about 144 km apart from each other in Korea. For the test, a 50-year δ18OTR time series (1966–2015) was developed using four trees from each tree species which are Pinus densiflora and Quercus mongolica from Songnisan National Park and Taxus cuspidata, Pinus koraiensis, Abies koreana, and Quercus mongolica from Jirisan National Park. Their synchronizations were evaluated using t-value, Gleichläufigkeit (Glk), and Expressed Population Signal (EPS). The mean t-values and Glk scores within the tree species ranged 5.2–11.2 (p

Abstract Background Adults with unoperated congenitally corrected transposition of the great arteries are rare but form a distinct group among adults with congenital heart disease. Patients with congenitally corrected transposition of the great arteries often have one or more associated cardiac anomalies that dictate the need for, and timing of, surgical intervention in childhood. However, in a proportion of patients, the hemodynamics does not require surgical attention during childhood, and, in some patients, a correct diagnosis is not established until adulthood. Here we report an adult case of unoperated congenitally corrected transposition of the great arteries with a large ventricular septal defect and probable pulmonary arterial hypertension. Case presentation Our patient was a 46-year-old Korean man. Transthoracic echocardiography and cardiac catheterization demonstrated hemodynamically balanced ventricles with a non-regurgitant systemic atrioventricular valve, normal pulmonary arterial pressure, and a reasonable difference between the oxygen saturation values of the aorta and pulmonary trunk, even with the presence of a large ventricular septal defect. Further morphological assessments using cardiac computed tomography and three-dimensional modeling/printing of his heart revealed that the mitral valve was straddling over the posteriorly positioned ventricular septal defect, which could explain the functional and anatomical subvalvular pulmonary stenosis and a small amount of shunt flow through the large ventricular septal defect. We interpreted this combination of cardiac defects as able to sustain his stable cardiac function. Thus, we decided to maintain his unoperated status. Conclusion A detailed anatomical understanding based on transthoracic echocardiography, cardiac computed tomography, and three-dimensional printing can justify a decision to not operate in cases of congenitally corrected transposition of the great arteries with hemodynamically balanced pulmonary stenosis and a ventricular septal defect, as observed in the present case.

Primary cardiac tumors are rare, with a prevalence of 0.001-0.2%. Among such tumors, cardiac hemangioendotheliomas are some of the most uncommon. In Korea, there have been no reports of hemangioendothelioma occurring in the heart of infants. We herein report a case of an infant that was admitted to our medical center and presented with cough and a runny nose. The initial diagnosis was acute bronchiolitis. Cardiomegaly was observed on chest radiography. Echocardiography revealed a tumor measuring 3.5×4.0 cm in the right atrium. The infant was transferred to a tertiary medical center for tumor excision. The excised lesion was 3.8×3×3.2 cm in size, and biopsy confirmed a diagnosis of hemangioendothelioma. In this case report, we describe our experience with a rare case involving cardiac tumor in an infant with an upper respiratory tract infection.

Background Noninvasive cardiac radioablation is employed to treat ventricular arrhythmia. However, myocardial changes leading to early‐period antiarrhythmic effects induced by high‐dose irradiation are unknown. This study investigated dose‐responsive histologic, ultrastructural, and functional changes within 1 month after irradiation in rat heart. Methods and Results Whole hearts of wild‐type Lewis rats (N=95) were irradiated with single fraction 20, 25, 30, 40, or 50 Gy and explanted at 1 day or 1, 2, 3, or 4 weeks’ postirradiation. Microscopic pathologic changes of cardiac structures by light microscope with immunohistopathologic staining, ultrastructure by electron microscopy, and functional evaluation by ECG and echocardiography were studied. Despite high‐dose irradiation, no myocardial necrosis and apoptosis were observed. Intercalated discs were widened and disrupted, forming uneven and twisted junctions between adjacent myocytes. Diffuse vacuolization peaked at 3 weeks, suggesting irradiation dose‐responsiveness, which was correlated with interstitial and intracellular edema. CD68 immunostaining accompanying vacuolization suggested mononuclear cell infiltration. These changes were prominent in working myocardium but not cardiac conduction tissue. Intracardiac conduction represented by PR and QTc intervals on ECG was delayed compared with baseline measurements. ST segment was initially depressed and gradually elevated. Ventricular chamber dimensions and function remained intact without pericardial effusion. Conclusions Mononuclear cell–related intracellular and extracellular edema with diffuse vacuolization and intercalated disc widening were observed within 1 month after high‐dose irradiation. ECG indicated intracardiac conduction delay with prominent ST‐segment changes. These observations suggest that early antiarrhythmic effects after cardiac radioablation result from conduction disturbances and membrane potential alterations without necrosis.

Abstract Background Pathology reports are written in free-text form, which precludes efficient data gathering. We aimed to overcome this limitation and design an automated system for extracting biomarker profiles from accumulated pathology reports. Methods We designed a new data model for representing biomarker knowledge. The automated system parses immunohistochemistry reports based on a “slide paragraph” unit defined as a set of immunohistochemistry findings obtained for the same tissue slide. Pathology reports are parsed using context-free grammar for immunohistochemistry, and using a tree-like structure for surgical pathology. The performance of the approach was validated on manually annotated pathology reports of 100 randomly selected patients managed at Seoul National University Hospital. Results High F-scores were obtained for parsing biomarker name and corresponding test results (0.999 and 0.998, respectively) from the immunohistochemistry reports, compared to relatively poor performance for parsing surgical pathology findings. However, applying the proposed approach to our single-center dataset revealed information on 221 unique biomarkers, which represents a richer result than biomarker profiles obtained based on the published literature. Owing to the data representation model, the proposed approach can associate biomarker profiles extracted from an immunohistochemistry report with corresponding pathology findings listed in one or more surgical pathology reports. Term variations are resolved by normalization to corresponding preferred terms determined by expanded dictionary look-up and text similarity-based search. Conclusions Our proposed approach for biomarker data extraction addresses key limitations regarding data representation and can handle reports prepared in the clinical setting, which often contain incomplete sentences, typographical errors, and inconsistent formatting.

The purpose of this study was to investigate the role of strong winds and aging in the death and/or decline in the growth of Korean fir on Mt. Halla in Korea. Bangeoreum (BA-S), Jindalrebat (JD-E), and Youngsil (YS-W) on the southern, eastern, and western slopes of Mt. Halla (ca. 1600 and 1700 m a.s.l.) were selected for the study. The site chronologies were established using more than 10 living Korean firs at each site. Additionally, to date the years and seasons of death of standing/fallen dead Korean firs, 15/15, 14/15, and 10/10 trees were selected at BA-S, JD-E, and YS-W, respectively. After adjusting the age with the period of growth up to the sampling point, the oldest Korean fir found among the living trees was 114 years old at JD-E and the oldest fir among the dead trees was 131 years old at JD-E. Besides this, most of the trees at BA-S and JD-E were found to have died between 2008 and 2015, and at irregular intervals between 1976 and 2013 at YS-W. Also, the maximum number of trees, that is, 62.7% died between spring and summer, followed by 20.9% between summer and autumn, and 16.4% between autumn of the current year and spring of the following year. Abrupt growth reductions occurred at BA-S and JD-E, and have become more significant in recent years, whereas at YS-W, the abrupt growth reduction and recovery occur in a cyclic order. The intensity and frequency of the typhoons increased from 2012, and this trend was in-line with the increased number of abrupt growth reductions at BA-S and JD-E. Therefore, the typhoons of 2012 are considered as the most likely influencing factor in death and/or growth reduction in Korean firs. In contrast, the decline in the growth of the Korean firs located on the windward slope (YS-W) showed a relationship with winds stronger than 25–33 m/s.

Arsenic (As) exists as highly toxic chemical species. Chronic exposure to its inorganic form can cause multiple organ failure and skin cancer in humans, warranting the need to determine the toxicity of each chemical species. This study evaluated the proportions of exposure to four chemical species of As (cAs), namely arsenite (AsIII), arsenate (AsV), monomethylarsinic acid (MMA), and dimethylarsenic acid (DMA), and it confirmed the necessity of evaluating biological exposure to cAs. Urine samples were collected from 457 subjects residing near 103 abandoned metal mines. Hydride generation atomic absorption spectroscopy (HG-AAS) was performed to measure the combined concentration of four cAs (hAsAAS). High-performance liquid chromatography and inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) were performed to determine the concentrations of the individual cAs and the sum of the four cAs (hAsICP). The proportions of AsV and MMA were relatively higher in the low-hAsICP concentration section. These findings suggest that hAsAAS, which is mainly used for its cost-efficiency, is limited for evaluating exposure. Though hAsAAS was found to exist in a low concentration, highly toxic AsV and MMA could be observed in high concentrations. Therefore, HPLC-ICP-MS is recommended for assessing cAs in environmentally vulnerable areas such as abandoned metal mines.

The current statistic data on the open access (OA) journals and institutional repositories show some successes and increased awareness on OA in Asian countries. There are several concerns, however, in regards to the access and use of articles by researchers together with the continued increase of libraries’ expenditure for journals. In the present article we introduce five solutions in the global and local perspectives. OA2020 initiative is a global initiative to transform existing journals to OA. Although the practical process of OA2020 remains a challenge, the transformation will increase OA without significant increase of journals and budgets for publishing. The promotion of the local and Asian journals is the second big challenge. Because these local or Asian journals still have important roles in the local research community, they should keep current publishing model of OA at the low cost but with high quality and the better access. The restructuring of the current library budget is the third challenge. The budget for periodicals should be reduced and the saved budget can be used to pay articles processing charge for OA and for purchasing monographs. The fourth important issue is ‘the digital blind spot at the young unemployed and retired elderly’. These groups of poorly supported and potentially important researchers have to be considered as a priority issue to the policies on OA and scholarly knowledge. Lastly, we believe there should be different needs for other activities: optimization of the searchable database, governmental policy on open science and international cooperation on OA.

Tree growth at northern boreal treelines is generally limited by summer temperature, hence tree rings serve as natural archives of past climatic conditions. However, there is increasing evidence that a changing summer climate as well as certain micro-site conditions can lead to a weakening or loss of the summer temperature signal in trees growing in treeline environments. This phenomenon poses a challenge to all applications relying on stable temperature-growth relationships such as temperature reconstructions and dynamic vegetation models. We tested the effect of differing ecological and climatological conditions on the summer temperature signal of Scots pine at its northern distribution limits by analyzing twelve sites distributed along a 2200 km gradient from Finland to Western Siberia (Russia). Two frequently used proxies in dendroclimatology, ring width and maximum latewood density, were correlated with summer temperature for the period 1901–2013 separately for (i) dry vs. wet micro-sites and (ii) years with dry/warm vs. wet/cold climate regimes prevailing during the growing season. Differing climate regimes significantly affected the temperature signal of Scots pine at about half of our sites: While correlations were stronger in wet/cold than in dry/warm years at most sites located in Russia, differing climate regimes had only little effect at Finnish sites. Both tree-ring proxies were affected in a similar way. Interestingly, micro-site differences significantly affected absolute tree growth, but had only minor effects on the climatic signal at our sites. We conclude that, despite the treeline-proximal location, growth-limiting conditions seem to be exceeded in dry/warm years at most Russian sites, leading to a weakening or loss of the summer temperature signal in Scots pine here. With projected temperature increase, unstable summer temperature signals in Scots pine tree rings might become more frequent, possibly affecting dendroclimatological applications and related fields.

Atrial anatomy and thickness may affect the electrical wave-dynamics of atrial fibrillation (AF). We explored the relationship between left atrial (LA) wall thickness (LAWT) or LA geometry and AF wave-dynamics.We included 15 patients with persistent AF (age, 62.3 ± 11.9 years) who underwent AF catheter ablation. We measured the LAWT, LA endocardial curvature, and SD-curvature (surface bumpiness) from preprocedural computed tomography images. We compared those anatomical characteristics with electrophysiologic parameters such as dominant frequency (DF), Shannon entropy (ShEn), or complex fractionated atrial electrogram (CFAE)-cycle length (CL), calculated from intracardiac bipolar electrograms (300-500 points, 5 s), acquired during ablation procedures.1. LAWT (excluding fat) varied widely among patients, locations, and types of AF. LAWT was inversely correlated with LA volume (r = -0.565, p = 0.028) and positively correlated with SD-curvature (r = 0.272, p < 0.001). 2. LAWT was positively correlated with ShEn (r = 0.233, p < 0.001) and negatively correlated with CFAE-CL (r = -0.107, p = 0.038). 3. In the multivariate linear regression analyses for AF wave-dynamics parameters, DF (β = -0.29 [95% CI -0.44--0.14], p < 0.001), ShEn (β = 0.19 [95% CI 0.12-0.25], p < 0.001), and CFAE-CL (β = 7.49 [95% CI 0.65-14.34], p = 0.032) were independently associated with LAWT.Regional LAWT is associated with LA structural features, and has significant correlations with the wave-dynamics parameters associated with electrical wavebreaks or rotors in patients with persistent AF.

Articles from open access and local journals are important resources for research in Korea and the usage trends of these articles are important indicators for the assessment of the current research practice. We analyzed an institutional collection of published papers from 1998 to 2014 authored by researchers from Seoul National University, and their references from papers published between 1998 and 2011. The published papers were collected from Web of Science or Scopus and were analyzed according to the proportion of articles from open access journals. Their cited references from published papers in Web of Science were analyzed according to the proportion of local (South Korean) or open access journals. The proportion of open access papers was relatively stable until 2006 (2.5 ~ 5.2% in Web of Science and 2.7 ~ 4.2% in Scopus), but then increased to 15.9% (Web of Science) or 18.5% (Scopus) in 2014. We analyzed 2,750,485 cited references from 52,295 published papers. We found that the overall proportion of cited articles from local journals was 1.8% and that for open access journals was 3.0%. Citations of open access articles have increased since 2006 to 4.1% in 2011, although the increase in open access article citations was less than for open access publications. The proportion of citations from local journals was even lower. We think that the publishing / citing mismatch is a term to describe this difference, which is an issue at Seoul National University, where the number of published papers at open access or local journals is increasing but the number of citations is not. The cause of this discrepancy is multi-factorial but the governmental / institutional policies, social / cultural issues and authors' citing behaviors will explain the mismatch. However, additional measures are also necessary, such as the development of an institutional citation database and improved search capabilities with respect to local and open access documents.