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Funding Acknowledgements Type of funding sources: None. Purpose We compared the efficacy, safety, and heart rate variability (HRV) after cryo-balloon (Cryo-PVI), high-power short-duration (HPSD-PVI) or conventional radiofrequency pulmonary vein isolation (conventional-PVI) in patients with atrial fibrillation (AF). Methods In this retrospective analysis of single-center cohort, we included 2,975 patients who underwent AF catheter ablation (74.1% male, median 60 years old, 74.1% paroxysmal AF). We compared the procedural factors, rhythm outcomes, complication rates, and post-procedural heart rate variability (HRV) between the Cryo-PVI (n=493), HPSD-PVI (n=638), and conventional-PVI (n=1,844). Results In spite of significantly shorter procedural time in the Cryo-PVI group (73 min for Cryo-PVI vs 110 min for HPSD-PVI vs 153 min for conventional-PVI, p Conclusion Cryo-PVI showed better rhythm outcome in patients with paroxysmal AF, but worse outcome in those with non-paroxysmal AF with higher long-term post-procedural sympathetic nervous activity as compared with conventional-PVI.

Funding Acknowledgements Type of funding sources: None. Background There is a genetic background in pulmonary vein (PV) development and atrial fibrillation (AF). However, the genetic trait of PV variations and their rhythm outcome after AF catheter ablation (AFCA) is unclear. Objective We explored the genetic and clinical characteristics and long-term rhythm outcomes of AF patients with PV variation or left common trunkus (LCT)-PV. Methods We included 2,897 AF patients (74.0% male, age 59.0 ± 10.7 years, 66.3% paroxysmal AF) with available genome-wide association study results, cardiac computed tomogram data, and protocol-based regular rhythm follow-up from the Yonsei AF ablation cohort database. We defined LCT-PV when the upper and lower PV separate at >10 mm distal to the left PV antrum margin. PV variations included both LCT-PV and accessory PVs. We analyzed the polygenic risk score (PRS) of 12 AF-associated genes (DSP, GJA1, HCN4, KCNQ1, NPPA, PITX2, RYR2, SCN5a, SHOX2, ATP2A2, TBX3, and TBX5) and long-term rhythm outcomes after AFCA. Results We found PV variation in 296 (10.2%) and LCT-PV in 102 (3.5%). PRS of 1,227 single nucleotid polymorphisms (SNPs) was significantly higher in PV variation patients (p=4.93e-08) and LCT-PV patients (p=1.95e-20). The patients with LCT-PV had higher CHA2DS2VASc scores (p=0.024) and lower atrial epicardial adipose tissue volume (p=0.034). During 39.7 ± 34.8 months follow-up period, LCT-PV patients had a significantly higher recurrence rate than their counter part in the paroxysmal AF sub-group (Log-rank p=0.036), but not in overall PV variations. LCT-PV with the highest 10% PRS was independently associated with AF recurrence after AFCA (HR 2.10, 95% CI 1.21-3.63, p=0.008). Conclusions Among the patients who underwent AFCA, PV variation, including LCT-PV, has a significant genetic background. The post-AFCA recurrence rate was significantly higher in patients with LCT-PV and high PRS, especially in paroxysmal AF.

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health and Welfare the Basic Science Research Program run by the National Research Foundation of Korea (NRF). Background Atrial fibrillation (AF) is a chronic progressive disease that recurs continuously even after successful AF catheter ablation (AFCA). Objective We explored the mechanism of this long-term recurrence by comparing the patient characteristics and redo-ablation findings. Methods Among 4,248 patients who underwent a de novo AFCA and protocol-based rhythm follow-up at single centers, we enrolled 1,417 patients (71.7% male, age 60.0 [52.0–67.0] years, 57.9% paroxysmal AF) who experienced clinical recurrences (CRs) of the disease, and divided them according to the period of recurrence: within one year (n=645), 1–2 years (n=339), 2–5 years (n=308), and after 5-years (CR>5yr, n=125). We also compared the redo-mapping and ablation outcomes in 198 patients. Results In patients with a CR>5yr, the proportion of paroxysmal AF was higher (p=0.031); however, the left atrial (LA) volume (computed tomography, p=0.003), LA voltage (p=0.003), frequency of early recurrence (p5yr was independently associated with the low LA volume (odds ratio [OR] 0.99 [0.99–1.00], p=0.019), low LA voltage (OR 0.62 [0.41–0.95], p=0.030), and lower early recurrence (OR 0.39 [0.23–0.64], p5yr, despite no difference in the de novo protocol. The rhythm outcome of repeat ablation procedures did not differ with the timing of the CR (log-rank p=0.330). Conclusions Patients with a later CR showed a smaller LA volume, lower LA voltage, and higher extra-PV triggers during the repeat procedure, suggesting progression of AF.

Funding Acknowledgements Type of funding sources: None. Introduction Atrial fibrillation catheter ablation (AFCA) improves sinus node function and may defer a permanent pacemaker (PPM) implantation. We explored the clinical and genetic characteristics of the patients with AF and sinus node dysfunction (SND) who eventually needed PPM implantation after AFCA. Methods Among 2,732 AF patients with genome-wide association study (GWAS, PMRA, Thermofisher scientific, MA, USA) data who underwent the first AFCA, 244 patients (65.0, IQR [59.0, 72.0] years, male 58.2%, paroxysmal AF 79.5%) had underlying SND before AFCA (class I indication for PPM). We retrospectively investigated clinical factors, single-nucleotide polymorphisms (SNPs), and their polygenic risk score (PRS) associated with PPM-AFCA. We defined the cut-off of PRS using the Youden index. Results During median 37.9 (IQR 20.3-77.9) months follow-up, 36 out of 244 patients (16.1%) with underlying SND eventually underwent PPM implantation after AFCA (PPM-AFCA). PPM-AFCA group a had a higher body mass index (p=0.013) and large left atrial (LA) dimension (p=0.006) than their counterpart. Among 44 SNPs related to AF and SND, the rs3922844 (p=0.003) near SCN5A and rs9320841 (p=0.011) and rs1015451 (p=0.046) near CJA1 were significantly associated with PPM-AFCA. The rate of PPM-AFCA implantation was significantly higher in the high PRS group (≥1.175, 25.6%) compared to the low PRS group ( Conclusions In AF patients with SND, 16% with the genetic background of SCN5A and CJA1 or large atrium eventually needed PPM implantation after AFCA.

Funding Acknowledgements Type of funding sources: None. Introduction Electrocardiography (ECG) can be easily obtained at a low cost and includes voltage and time interval representing heart conditions. We hypothesized that artificial intelligence (AI) detects a subtle abnormality in 12-lead ECG and may predict individual mortality. Methods Among 502,411 population in UK Biobank, 42,096 individuals had 12-lead ECG from 2013 to 2022. Among population with available ECG, 4,512 individuals were enrolled in this study adjusting the following inclusion criteria; age under 60 years, sinus rhythm, PR interval 120~200ms, QTc interval 350~460ms, and QRS duration 70~100ms. We developed and tested convolutional neural network (CNN) model to predict all cause death, cardiovascular (CV) death, or sudden cardiac arrest (SCA). The study population were divided into train (80%), validation (10%), and test (20%) set. Results Among 4,512 patients with median 3.7 years [IQR; 2.7-5.1] of follow-up, the rate of all-cause mortality was 11.6% (524). In overall study population, median age was 55.5 years and proportion of male sex was 42.2%. The patients with all-cause death were older (p Conclusions AI detects and predicts future all-cause death, CV death, and SCA in median of 2.6 years by analyzing standard 12-lead ECG in generally looking normal sinus rhythm.

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(2022R1I1A1A01071083). This work was also supported by the Korea Medical Device Development Fund grant funded by the Korea government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, the Ministry of Food and Drug Safety) (Project Number: RS-2022-00141473). Background In the planning of atrial fibrillation (AF)-related procedures, predicting left atrial (LA) anatomy and pulmonary vein (PV) diameter is important for the effectiveness and safety of the procedures but requires a labor-intensive measurement process. Here, we propose an artificial intelligence (AI) based PV diameter measurement algorithm for the computed tomogram (CT)-based automated PV evaluation. Methods We implemented a mesh-based convolutional neural network for the surface segmentation of four PVs and the LA appendage (LAA) in a 3D LA surface mesh. Our algorithm includes two originative methods of surface depth feature and cohesion loss function to improve the performance. We trained the model with the LA mesh of 210 AF patients’ CT scan and validated the accuracy of surface segmentation and PV diameter with independent 158 samples. Results Using an AI-based automated LA measurement model, we achieved an average Intersection over Union (IoU) of 83.4% and a regional IoU from 78.4 to 87.2 % in 158 LA meshes. When we added the surface depth feature, the IoU was improved by 31.7% compared to the conventional 3D feature. The cohesion loss function reduced the fragmentation rate of the surface label by 3.2%. Post-processed PV diameters did not differ from manually measured left (P=0.56) and right upper PV diameters (P=0.08) but differed in both lower PVs (p Conclusion We proposed an AI-guided automated algorithm for surface segmentation and PV diameter measurement and validated it at both upper PVs and the eccentricity of the PV ostia. Our algorithm can be applied to the automated sizing of LA appendage and improve labor-intensive manual segmentation.

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): a grant [2022R1I1A1A0106342211] from the Basic Science Research Program run by the National Research Foundation of Korea (NRF) which is funded by the Ministry of Science, ICT & Future Planning (MSIP) Background It has been suggested that the high dominant frequency (DF) site plays an atrial fibrillation (AF) driver, but its relationship with the atrial substrate voltage map (Vm) in the entire chamber AF map has yet to be studied. We explored the relationship between the DF site during AF and Vm in the entire chamber maps by applying the human left atrial (LA) electroanatomical map (EAM) to the digital twin AF map. Methods We acquired LA substrate Vm (at sinus rhythm, >800 points bipolar electrograms) of 110 patients with persistent AF (male 72.7%, 58.7±9.8 years old) who underwent AF catheter ablation. We applied EAM to digital twins (0.4 million nodes), reflecting anatomy, histology, and electrophysiology. We evaluated the highest 10% DF areas for 6 sec after inducing virtual AF. The correlation between the highest 10% DF and the low Vm areas ( Results The mean voltage of the entire LA area was 1.96±0.85 mV (2.19±0.82 mV extra-PV area, 1.33±0.93 mV PV area) in 110 patients. The correlation between low Vm and high DF areas was not significant in the entire LA (r=0.106, p Conclusion High DF site, a parameter representing a localized focal source, had statistically significant but very poor correlations with LA extra-PV voltage substrate in patients with persistent AF.

Background Although active rhythm control by atrial fibrillation (AF) catheter ablation (AFCA) reduces left atrial (LA) dimension, blunted atrial reverse remodeling can be observed in patients with significant atrial myopathy. We explored the characteristics and long-term outcomes of AF patients who showed blunted atrial reverse remodeling despite no AF recurrence within a year after AFCA. Methods Among a total of 2,756 patients with AFCA, we included 1,685 patients (74.8% male, 60.2±10.1 years old, 54.5% paroxysmal AF) who underwent both baseline and 1-year follow-up echocardiogram, baseline LA>40mm, and did not recur within a year. We divided them into tertile groups (T1–T3) based on one-year percent change of LA dimension after propensity matching for age, sex, AF type, and baseline LA dimension. We also investigated the patients' genetic characteristics with blunted LA reverse remodeling (T1) using a genome-wide association study (GWAS). Results Patients with blunted LA reverse remodeling (T1, n=424) were independently associated with body mass index (OR 1.082 [1.010–1.160], p=0.025), LA peak pressure (OR 1.010 [1.002–1.019], p=0.019), LA wall thickness (OR 0.448 [0.252–0.789], p=0.006), LA voltage (OR 0.651 [0.463–0.907], p=0.012), and pericardial fat volume (OR 1.004 [1.001–1.008], p=0.014). Throughout 65.9±37.4 months of follow-up, the incidence of AF recurrence a year after the procedure was significantly higher in the T1 group than in T2 or T3 groups (Log-rank p Conclusions Patients with blunted LA reverse remodeling after AFCA were independently associated with low LA voltage, thin wall thickness, high LA pressure, and fat volume, and have a genetic background. Long-term clinical recurrence a year after AFCA was higher in this patient group with suspicious atrial myopathy. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health and WelfareNational Research Foundation of Korea

The present work studies the adsorption of ethylene on Ni-H-Beta particles to unravel the roles of nickel and Brønsted sites in the catalytic oligomerization of ethylene. Three models (i.e., two based on the Cossee–Arlman mechanism and one based on the metallacycle mechanism) are examined in terms of the nature of the active sites and the adsorption mechanism involved in the ethylene coordination step. The results are consistent with the participation of two active sites in the formation of [Ni(II)-H]+ Cossee–Arlman centers and also suggest that ethylene dissociates upon adsorption on [Ni(II)-H]+ sites. Further characterization of Ni-H-Beta catalysts prepared at different nickel loadings and silica-to-alumina ratios reveals that highly dispersed Ni2+ exists on the catalyst surface and interacts with the catalyst’s lattice oxygen and free NiO crystals. At the same time, the kinetic results indicate that Brønsted sites may form isolated nickel-hydride ([Ni(II)-H]+) centers on the catalyst surface. In addition, the presence of residual, noncoordinated Ni2+ and Brønsted sites (not involved in the formation of [Ni(II)-H]+ sites) shows a reduced probability of the formation of nickel-hydride sites, hindering the conversion rate of ethylene. A mechanism for forming [Ni(II)-H]+ centers is proposed, involving ethylene adsorption over Ni2+ and a Brønsted site. This research has important implications for improving ethylene oligomerization processes over nickel-based heterogeneous catalysts.

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health and Welfare, National Research Foundation of Korea (NRF) Abstract Background The ZFHX3 gene (16q22) is the second most highly associated gene with atrial fibrillation (AF) and is related to inflammation and fibrosis. Purpose We hypothesized that ZFHX3 is associated with extra-pulmonary vein (PV) triggers, left atrial (LA) structural remodeling, and poor rhythm outcomes of AF catheter ablation (AFCA). Methods We included 1782 patients who underwent a de novo AFCA (73.5% male, 59.4±10.8 years old, 65.9% paroxysmal AF) and genome-wide association study and divided them into discovery (n=891) and replication cohorts (n=891). All included patients underwent isoproterenol provocation tests and LA voltage mapping. We analyzed the ZFHX3, extra-PV trigger-related factors, and rhythm outcomes. Results Among 14 single-nucleotide polymorphisms (SNPs) of ZFHX3, rs13336412, rs61208973, rs2106259, rs12927436, and rs1858801 were associated with extra-PV triggers. In the overall patient group, extra-PV triggers were independently associated with the ZFHX3 polygenic risk score (PRS) (OR 1.65 [1.22-2.22], p=0.001, model 1) and a low LA voltage (OR 0.74 [0.56-0.97], p=0.029, model 2). During 49.9±40.3 months of follow-up, clinical recurrence of AF was significantly higher in patients with extra-PV triggers (Log-rank p Conclusions The extra-PV triggers had significant associations with both ZFHX3 genetic polymorphisms and acquired LA remodeling. Although extra-PV triggers were an independent predictor of AF recurrence after AFCA, the studied AF risk SNPs intronic in ZFHX3 were not associated with AF recurrence.

To identify the agreement on Lung CT Screening Reporting and Data System 4X categorization between radiologists and an expert-adjudicated reference standard and to investigate whether training led to improvement of the agreement measures and diagnostic potential for lung cancer. Category 4 nodules in the Korean Lung Cancer Screening Project were identified retrospectively, and each 4X nodule was matched with one 4A or 4B nodule. An expert panel re-evaluated the categories and determined the reference standard. Nineteen radiologists were asked to determine the presence of CT features of malignancy and 4X categorization for each nodule. A review was performed in two sessions, and training material was given after session 1. Agreement on 4X categorization between radiologists and the expert-adjudicated reference standard and agreement between radiologist-assessed 4X categorization and lung cancer diagnosis were evaluated. The 48 expert-adjudicated 4X nodules and 64 non-4X nodules were evenly distributed in each session. The proportion of category 4X decreased after training (56.4% ± 16.9% vs. 33.4% ± 8.0%; p 0.05). All agreement measures between radiologist-assessed 4X categorization and lung cancer diagnosis increased in session 2 (p < 0.05). Radiologist training can improve reader agreement on 4X categorization, leading to enhanced diagnostic performance for lung cancer. • Agreement on 4X categorization between radiologists and an expert-adjudicated reference standard was initially poor, but improved significantly after training. • The mean proportion of 4X categorization by 19 radiologists decreased from 56.4% ± 16.9% in session 1 to 33.4% ± 8.0% in session 2. • All agreement measures between the 4X categorization and lung cancer diagnosis increased significantly in session 2, implying that appropriate training and guidance increased the diagnostic potential of category 4X.

Effective flame anchoring maximizes the low-emissions operating window of gas-turbine systems featuring closely spaced, multiple lean flames on single injector units. The complex flame-flow interactions inherent to such designs are not well understood, in particular, at part-load gas turbine conditions. In the present work, large eddy simulation (LES) was used to investigate flames in an optically accessible, confined, linear array of five industrial swirl injector elements. Well-anchored, partially attached and fully lifted flames were observed and three cases corresponding to these were selected for modeling. The dynamically thickened flame (DTF) model was used with a newly developed reduced chemical kinetics scheme that contains low temperature reaction pathways. Chemical explosive mode analysis (CEMA) shows that the flames exhibit thin ignition zones near their base, while a more distributed region of strongly positive modes occur downstream when a transition to partial blow-off takes place. Extinctions are frequent in this region and create broken reaction zones which seem to exhibit both autoignition as well as flamelet characteristics. Further decrease in reactivity leads to a fully lifted flame. It is clear that part-load conditions are best investigated by models that are combustion regime independent.

For pediatric inguinal hernia repairs (IHRs), open IHR (high ligation) has long been a gold standard. Recently laparoscopic IHR (LIHR) was introduced as a new treatment modality and has been performed more frequently in Korea. Unlike adults, LIHR in children is still controversial. In the present study, we investigate the short-term outcomes of pediatric LIHR in Korea using nationwide inpatient data. We analyzed clinical practice for IHRs from 2011 to 2015 using Korean Health Insurance Review and Assessment Service-National Inpatient Sample. A total of 5281 patients 15 years old or younger underwent 5356 IHRs: 4507 OIHRs and 849 LIHRs. M:F ratio was 2.4:1. The proportion of LIHRs was only 1.8% at the beginning but had been continuously increased up to 29.8% at the end of the study period. LIHRs were closely related to synchronous bilateral inguinal hernia repairs (SBIHRs). Overall, SBIHRs were performed in 10.9% of open and 49.2% of LIHRs. Metachronous contralateral IHRs (MCIHRs) after initial unilateral IHRs were significantly more frequent after OIHRs (1.7%, 69/3, 951) than after LIHRs (0.2%, 1/427). Recurrence rate per side during study period was 0.1% (6/4, 993) after OIHRs and 0.2% (2/1, 259) after LIHRs, respectively (statistically insignificant). Nationwide inpatient data showed that LIHRs in pediatric patients had recently been increasingly performed in Korea. LIHRs facilitated SBIHRs, which, in turn, decreased the needs of MCIHRs. However limited numbers of patients might actually have benefited from them. Early recurrence after primary IHRs in children is quite low regardless of way of approach.

In the present study, using eddy current technique (ECT), we explored two kinds of defects commonly found in railroad monitoring. The first one is cracks initiated on the surface of rail head which slowly progresses into vertical rail plane, the second one is squat type of defects grown on the running head surface. A reliable ECT system equipped with plus point ECT probe was developed and experiments were conducted on a 10 mm thick medium carbon steel plate with two kinds of machined defects varying on their dimensions. An optimized plus point probe was fabricated for the experimental purpose and a Lab VIEW based program was developed to interactively collect and analyze the obtained data. Predefined defects (slit, squat) with changing defect depth and length for both the cases machined on S45C medium carbon steel plate were examined. Prior to the experiments, simulation studies were conducted to fully understand the defect dimensions and optimized the experimental parameters. Response signal parameters, amplitude and phase were analyzed to characterize the defect features. The designed system shows better performance to detect the deepest defect up to 5 mm approximately, and it can be extended further with moderate signal to noise ratio. Two kinds of defects can be categorized according to the obtained signals.

BackgroundTumor necrosis factor inhibitors (TNFi) have become a mainstay of management for axial spondyloarthritis (axSpA). However, it remains unclear whether patients with axSpA should continue the standard-dose TNFi after achieving stable disease activity. Although complete discontinuation of TNFi is followed by early relapse in most cases, several studies documented that reduced doses of TNFi in patients with prolonged low disease activity showed similar effects on disease control and drug survival compared to standard dose of TNFi. One of the main problem in the dose-tapering strategies for TNFi is a selection of the appropriate patient. However, there has been a lack of robust evidence regarding clinical factors predicting the flare after tapering of TNFi in patients with axSpA.ObjectivesThis study aims to develop and validate the prediction model to select the patients in whom tapering of TNFi does not lead to flare.MethodsWe used the data from Korean College of Rheumatology Biologics registry, which included a total of 1,730 patients receiving biologic DMARD from 2017 to 2019 in South Korea. In this study, a total of 526 patients who were initially treated with the standard-dose TNFi and tapered the dose after at least 1 year of the treatment were analyzed. Dose quotient (DQ, 0-1) was applied to quantified TNFi used during interval. The main outcome was an occurrence of flare defined as ASDAS-CRP score of ≥2.1 after 1 year of tapering TNFi. To develop the prediction model, clinical factors having relevant association (p < 0.1) with the outcome were first selected as candidate predictors. Logistic regression using a stepwise approach through backward elimination was used for the final model.ResultsPatients’ mean (SD) age was 37.5 (11.9) years, 418 (79.5%) were men, and 474 (90.1%) were HLA-B27 positive. Mean disease duration was 5.0 (6.1) years and 433 (82.3%) were TNF naïve. The mean BASFI and ASDAS-CRP at baseline were 3.4 (2.6) and 3.7 (1.0), respectively. Approximately two-thirds of the patients (65.8%) were initiated TNFi tapering at the first 1 or 2 years from baseline. At the time of TNFi tapering, the mean DQ was 0.67 (0.15) and 381 (72.4%) were prescribed concurrently with NSAIDs, and the mean BASFI and ASDAS-CRP were 1.3 (1.8) and 1.6 (0.9), respectively. During 12 months of follow up starting from the TNFi tapering, 127 (24.1%) experienced the flare. The multivariable analysis revealed that HLA-B27 positivity (OR 0.337; 95% CI 0.161-0.705; p=0.004), inflammatory back pain (OR 2.920; 95% CI 1.283-6.648; p=0.011), ASDAS-CRP at tapering (OR 2.798; 95% CI 2.030-3.856; pFigure 1.Apparent performance of developed model for prediction of flare after 12 months of tumor necrosis factor inhibitors tapering.ConclusionWe developed the prediction model for the flare after 12 months of TNFi tapering in patients with axSpA. It might be applicable in real world setting, although external validation will be required in the future investigation.References[1]Zavada J, et al. Ann Rheum Dis. 2016;75(1):96-102.AcknowledgementsWe greatly thank to the the Clinical Research Committee of the Korean College of Rheumatology and all participating hospitals.Disclosure of InterestsNone declared

Korea Christian churches and missionaries have a prominent presence around the world. In cities such as Yanji and Los Angeles, Korean churches are an essential part of century-old Korean ethnic communities that trace their origins to Japanese colonization that began in the late-1800s. More recently, the economic success of South Korean corporations has resulted in Korean churches and missionaries in global metropoles such as Beijing, London, and Singapore that serve thriving Korean communities anchored by corporate transnationals, entrepreneurs, and international students. This same economic growth has financed Korean missionaries from Africa to Central Asia to undertake projects ranging from health care to education. While all Korean churches and missionaries have comfortably imbued the global religion of Christianity with their national and ethnic identity, the differences in national and local contexts shape their individual beliefs and practices. Given the dramatic changes in both Korean and its diasporic histories, each Korean church selects from rich and complex vocabularies of religion, nation, ethnicity, and community to negotiate and articulate its mission and identity. Within this context, this article focuses on two Korean churches-one from Beijing and another from Tokyo-as emblematic case studies of global religion and local faith.

Background:Interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are major causes of death in systemic sclerosis (SSc). Six-minute-walk test (6MWT) is a standard outcome measure for exercise capacity in cardiopulmonary diseases. However, the results of 6MWT may not reflect real cardiopulmonary function of SSc patients in whom musculoskeletal system is frequently inflicted.Objectives:This study aimed to evaluate the clinical utility of breath-holding test (BHT) in evaluating cardiopulmonary function in SSc patients, as compared with 6MWT.Methods:Seventy-two patients with SSc were prospectively enrolled and underwent BHT and 6MWT with measurement of Borg score and Scleroderma Health Assessment Questionnaire (SHAQ). Data on diffusing capacity for carbon monoxide (DLCO, %), forced vital capacity (FVC, % and liters), and ejection fraction and pulmonary arterial systolic pressure (PASP) measured by transthoracic echocardiography (TTE), were also collected. For BHT, participants were required to make a maximum expiration followed by a maximum inspiration and to hold the breath as long as possible at maximum inspiratory level. This procedure was repeated three times, with 5-minute intervals. 6MWT was performed according to the American Thoracic Society guidelines. Pearson’s correlation test was applied to demonstrate the relationship between BHT results and each clinical parameter.Results:Among 72 (66 female) patients, mean (SD) age was 57.1 (11.1) years, modified Rodnan skin score 10.6 (10.5), SHAQ 0.64 (0.61) and 6MWT distance 473.5 (95.5) m. Mean BHT time was 35.05 (14.90) sec at the first time, 38.92 (16.14) sec at the second time, and 41.11 (17.71) sec at the third time. The BHT time showed a statistically significant negative correlation with Borg scale (pre-test, r = -0.336, p = 0.002; post-test, r = -0.252, p = 0.034; Figure 1 and Table 1), while 6MWT showed a negative correlation with only post-test Borg scale (pre-test, r = -0.113 p = 0.343; post-test, r = -0.351 p = 0.002; Table 1). The BHT time was positively correlated with DLCO (%, r = 0.409, p < 0.001) and FVC (liters, r = 0.402, p < 0.001) (Table 1). We also found a statistically significant correlation between BHT time and SHAQ score (r = -0.451, p < 0.001; Table 1). However, EF and PASP by TTE showed no significant relationship with BHT time (EF, r = -0.108, p = 0.374; PASP, r = -0.246, p = 0.054; Table 1).Table 1.Pearson’s correlation coefficients (r) for the relation between BHT and clinical parameters in comparison to 6MWT.Pre-test Borg scalePost-test Borg scaleDLCO(%)FVC(L)FVC(%)FVC/DLCOEF(%)PSAP(mm Hg)SHAQ (score)BHT (sec)-0.366**-0.252*0.409***0.402**0.191-0.244***-0.108-0.246-0.451***6MWT (m)-0.113-0.351**0.297*0.321**0.063-0.250*0.137-0.354**-0.531***BHT, breath-holding test; 6MWT, 6-minute-walk test; DLCO, diffusing capacity for carbon monoxide; FVC, forced vital capacity; EF, ejection fraction estimated by transthoracic echocardiography; SHAQ, Scleroderma Health Assessment Questionnaire.* p < 0.05, ** p < 0.01, *** p < 0.001Figure 1.Association of Borg dyspnea scale with breath-holding time.Conclusion:The BHT is a simple, safe, and less time-consuming test, reflective of pulmonary parameters and SHAQ, as compared with 6MWT. Our results suggest that the BHT might be a useful surrogate marker of cardiopulmonary capacity in SSc patients.References:[1]Villalba WO, Sampaio-Barros PD, Pereira MC, Cerqueira EM, Leme CA, Jr., Marques-Neto JF, et al. Six-minute walk test for the evaluation of pulmonary disease severity in scleroderma patients. Chest. 2007;131(1):217-22.[2]Garin MC, Highland KB, Silver RM, Strange C. Limitations to the 6-minute walk test in interstitial lung disease and pulmonary hypertension in scleroderma. J Rheumatol. 2009;36(2):330-6.[3]Barnai M, Laki I, Gyurkovits K, Angyan L, Horvath G. Relationship between breath-hold time and physical performance in patients with cystic fibrosis. Eur J Appl Physiol. 2005;95(2-3):172-8.Acknowledgements:This study would not have been possible without help from research assistant, Sung-Soon Cho.Disclosure of Interests:Jina Yeo: None declared, Mi Hyeon Kim: None declared, Jun Won Park: None declared, Jin Kyun Park: None declared, Eun Bong Lee Consultant of: Pfizer, Grant/research support from: GC Pharma and Handok Inc.

For pediatric inguinal hernia repairs (IHRs), open IHR (high ligation) has long been a gold standard. Recently laparoscopic IHR (LIHR) was introduced as a new treatment modality and has been performed more frequently in Korea. Unlike adults, LIHR in children is still controversial. In the present study, we investigate the short-term outcomes of pediatric LIHR in Korea using nationwide inpatient data.We analyzed clinical practice for IHRs from 2011 to 2015 using Korean Health Insurance Review and Assessment Service-National Inpatient Sample.A total of 5281 patients 15 years old or younger underwent 5356 IHRs: 4507 OIHRs and 849 LIHRs. M:F ratio was 2.4:1. The proportion of LIHRs was only 1.8% at the beginning but had been continuously increased up to 29.8% at the end of the study period. LIHRs were closely related to synchronous bilateral inguinal hernia repairs (SBIHRs). Overall, SBIHRs were performed in 10.9% of open and 49.2% of LIHRs. Metachronous contralateral IHRs (MCIHRs) after initial unilateral IHRs were significantly more frequent after OIHRs (1.7%, 69/3, 951) than after LIHRs (0.2%, 1/427). Recurrence rate per side during study period was 0.1% (6/4, 993) after OIHRs and 0.2% (2/1, 259) after LIHRs, respectively (statistically insignificant).Nationwide inpatient data showed that LIHRs in pediatric patients had recently been increasingly performed in Korea. LIHRs facilitated SBIHRs, which, in turn, decreased the needs of MCIHRs. However limited numbers of patients might actually have benefited from them. Early recurrence after primary IHRs in children is quite low regardless of way of approach.

Computational approaches have been suggested as an informative tool for risk assessment of nanomaterials. Nano (quantitative) structure-activity relationship, nano-(Q)SAR, models have been developed to predict toxicity of metal oxide (MOx) nanoparticles (NPs); however, the packing structure and cluster of nanoparticle have been included for the descriptor calculation in only two studies. This study proposed spherical cluster and hydroxyl metal coordination complex to calculate descriptors for development of nanoparticle cytotoxicity classification model. The model cluster was generated from metal (M) or MOx crystal structure to calculate physicochemical properties of M/MOx NPs and the hydroxyl metal coordination complex was used to calculate the properties of the metal cation in an aqueous environment. Data were collected for 2 M and 19 MOx NPs in human bronchial epithelial cell lines and murine myeloid cell lines at 100 μg/ml after 24 hours exposure. The model was developed with scaled HOMO energy of the model cluster and polarizability of the hydroxyl metal coordination complex, as reactivity of the particles and the cations explained cause of cytotoxic action by M/MOx NPs. As the developed model achieved 90.31% accuracy, the classification model in this work can be used for virtual screening of toxic action of M/MOx NPs.

Summary The microstructure of rock was numerically reproduced by a polygonal grain-based model, and its mechanical behavior was examined by performing the uniaxial compression test and Brazilian tests via the Universal Distinct Element Code. The numerical results of the model demonstrated good agreement with the experimental results obtained with rock specimens in terms of the stress–strain behavior, strength characteristics, and brittle fracture phenomenon. An encouraging result is that the grain-based model-Universal Distinct Element Code model can reproduce a low ratio of tensile to compressive strength of 1/20 to 1/10 without the need for an additional process. This finding is ascribed to the fact that the geometrical features of polygons can effectively capture the effects of angularity, finite rotation, and interlocking of grains that exist in reality. A numerical methodology to monitor the evolution of micro-cracks was developed, which enabled us to examine the progressive process of the failure and distinguish the contribution of tensile cracking to the process from that of shear cracking. From the observations of the micro-cracking process in reference to the stress–strain relation, crack initiation stress, and crack damage stress, it can be concluded that the failure process of the model closely resembles the microscopic observations of rock. We also carried out a parametric study to examine the relationships between the microscopic properties and the macroscopic behavior of the model. Depending on the micro-properties, the model exhibited a variety of responses to the external load in terms of the strength and deformation characteristics, the evolution of micro-cracks, and the post-peak behavior. Copyright © 2016 John Wiley & Sons, Ltd.