Search

Abstract This study aims to propose a generative deep learning model (GDLM) based on a variational autoencoder that predicts macular optical coherence tomography (OCT) images following full-thickness macular hole (FTMH) surgery and evaluate its clinical accuracy. Preoperative and 6-month postoperative swept-source OCT data were collected from 150 patients with successfully closed FTMH using 6 × 6 mm2 macular volume scan datasets. Randomly selected and augmented 120,000 training and 5000 validation pairs of OCT images were used to train the GDLM. We assessed the accuracy and F1 score of concordance for neurosensory retinal areas, performed Bland–Altman analysis of foveolar height (FH) and mean foveal thickness (MFT), and predicted postoperative external limiting membrane (ELM) and ellipsoid zone (EZ) restoration accuracy between artificial intelligence (AI)-OCT and ground truth (GT)-OCT images. Accuracy and F1 scores were 94.7% and 0.891, respectively. Average FH (228.2 vs. 233.4 μm, P = 0.587) and MFT (271.4 vs. 273.3 μm, P = 0.819) were similar between AI- and GT-OCT images, within 30.0% differences of 95% limits of agreement. ELM and EZ recovery prediction accuracy was 88.0% and 92.0%, respectively. The proposed GDLM accurately predicted macular OCT images following FTMH surgery, aiding patient and surgeon understanding of postoperative macular features.

Abstract We estimate the number of physical qubits and execution time by decomposing an implementation of Shor’s algorithm for elliptic curve discrete logarithms into universal gate units at the logical level when surface codes are used. We herein also present modified quantum circuits for elliptic curve discrete logarithms and compare our results with those of the original quantum circuit implementations at the physical level. Through the analysis, we show that the use of more logical qubits in quantum algorithms does not always lead to the use of more physical qubits. We assumed using rotated surface code and logical qubits with all-to-all connectivity. The number of physical qubits and execution time are expressed in terms of bit length, physical gate error rate, and probability of algorithm failure. In addition, we compare our results with the number of physical qubits and execution time of Shor’s factoring algorithm to assess the risk of attack by quantum computers in RSA and elliptic curve cryptography.

In this paper, a method for power distribution control in communication-free multiple-input and multiple-output (MIMO) wireless power transfer (WPT) through load impedance and mutual inductance estimation is proposed. The proposed method intentionally adjusts the resonant frequency of the secondary side to introduce a reactance, utilizing this information to estimate the load impedance and mutual inductance for power distribution control without the need for communication. The principle of the power transmission algorithm proposed in this paper is designed to be effective regardless of whether the power or frequency is high or low. Therefore, the experimental setup is not designed by specifying the coil size, system frequency, or separation distance between the transmitting (Tx) and receiving (Rx) coils to match specific real applications. To verify the proposed method, four Tx coils and two Rx coils of arbitrary sizes are fabricated, and a MIMO-WPT environment is implemented using LC matching. In the experiment, since the circuit designed for the Tx is not capable of withstanding high currents, power is intentionally transmitted at a low range of less than 1 W to validate the feasibility of the method. Because the transmission power range is set low, the distance between the Tx and Rx coils is set close to approximately 2 cm. Consequently, it is verified that the algorithm for parameter estimation and power transmission to multiple Rx coils is effective as long as the environment allows for the current flowing through the Tx coil to change due to the presence of the Rx coils. All experiments for uniform and non-uniform power distribution to two Rx coils showed good agreement between the desired power and the actual received power.

AbstractA yeast strain, designated as JAF-11T, was isolated from flower of Prunus mume Sieb. et Zucc. in Gwangyang, Republic of Korea. Phylogenetic analysis showed that strain JAF-11T was closely related to Neodothiora populina CPC 39399T with 2.07 % sequence divergence (12 nucleotide substitutions and three gaps in 581 nucleotides) in the D1/D2 domain of the large subunit (LSU) rRNA gene, and Rhizosphaera macrospora CBS 208.79T with 4.66 % sequence divergence (25 nucleotide substitutions and five gaps in 535 nucleotides) in the internal transcribed spacer (ITS) region. Further analysis based on the concatenated sequences of the D1/D2 domain of the LSU rRNA gene and the ITS region confirmed that strain JAF-11T was well-separated from Neodothiora populina CPC 39399T. In addition to the phylogenetic differences, strain JAF-11T was distinguished from its closest species, Neodothiora populina CPC 39399T and Rhizosphaera macrospora CBS 208.79T belonging to the family Dothioraceae by its phenotypic characteristics, such as assimilation of carbon sources. Hence, the name Neodothiora pruni sp. nov. is proposed with type strain JAF-11T (KACC 48808T; MB 850034).

BackgroundRecently, anti-programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immunotherapy offers promising results for advanced biliary tract cancer (BTC). However, patients show highly heterogeneous responses to treatment, and predictive biomarkers are lacking. We performed a systematic review and meta-analysis to assess the potential of PD-L1 expression as a biomarker for treatment response and survival in patients with BTC undergoing anti-PD-1/PD-L1 therapy.MethodsWe conducted a comprehensive systematic literature search through June 2023, utilizing the PubMed, EMBASE, and Cochrane Library databases. The outcomes of interest included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) according to PD-L1 expression. Subgroup analyses and meta-regression were performed to identify possible sources of heterogeneity.ResultsA total of 30 studies was included in the final analysis. Pooled analysis showed no significant differences in ORR (odds ratio [OR], 1.56; 95% confidence intervals [CIs], 0.94-2.56) and DCR (OR, 1.84; 95% CIs, 0.88-3.82) between PD-L1 (+) and PD-L1 (-) patients. In contrast, survival analysis showed improved PFS (hazard ratio [HR], 0.54, 95% CIs, 0.41-0.71) and OS (HR, 0.58; 95% CI, 0.47-0.72) among PD-L1 (+) patients compared to PD-L1 (-) patients. Sensitivity analysis excluding retrospective studies showed no significant differences with the primary results. Furthermore, meta-regression demonstrated that drug target (PD-1 vs. PD-L1), presence of additional intervention (monotherapy vs. combination therapy), and PD-L1 cut-off level (1% vs. ≥5%) significantly affected the predictive value of PD-L1 expression.ConclusionPD-L1 expression might be a helpful biomarker for predicting PFS and OS in patients with BTC undergoing anti-PD-1/PD-L1 therapy. The predictive value of PD-L1 expression can be significantly influenced by diagnostic or treatment variables.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO, identifier CRD42023434114.

This paper proposes a novel method to predict the radar detection errors in a complex environment by considering slant range and angular error. This method involves analysis of the electromagnetic wave propagation path loss in troposphere using discrete mixed Fourier transform based split–step parabolic equation. For analysis, modeling of the terrain profile using a digital elevation model and estimating the refractive index by interpolating upper–air observations is conducted. The direction of refracted antenna’s main beam is predicted using the path loss, and by comparing it with the antenna boresight, the radar errors are computed according to the received timing of the radar echo. To apply the proposed method to real scenarios, the atmospheric environment within the analysis area is modeled using meteorological data collected on a specific day. By applying the proposed method to an arbitrary date and location, the radar errors in a long–range propagation environment where refraction occurs are analyzed.

Abstract Biliary strictures can have several benign or malignant causes. We attempted to determine the usefulness of establishing a diagnosis using self-expandable metal stents (SEMS) in a prospective series of patients with suspected malignant biliary obstruction. Data of patients who underwent SEMS removal from August 2016 to December 2019 were collected. During this period, 55 patients underwent endobiliary biopsy and SEMS insertion and removal. Fifty-five consecutive patients (mean age, 69 years; range 53–90 years) were enrolled, and of these, 37 were male and 18 were female. A final diagnosis was established using biopsy specimens in 37 cases (67.3%) and surgical specimens in 6 cases (10.9%), with 12 cases (21.8%) diagnosed on radiological follow-up. The final diagnoses included malignancy in 34 cases (61.8%) and benign stricture in 21 cases (38.2%). Endobiliary biopsy had a sensitivity and specificity of 44.1% and 95.2%, whereas SEMS cytology had a sensitivity and specificity of 52.9% and 100%, respectively. Combining endobiliary biopsy and/or SEMS cytology yielded a sensitivity and specificity of 73.5% and 95.2%, respectively. (1) The use of biopsy results alone as a diagnostic tool yielded an area under the receiver operating characteristic curve (AUC) of 0.70 (0.60–0.79). (2) The addition of SEMS to the biopsy results yielded an AUC of 0.86 (0.78–0.94). (3) The addition of CA 19–9 levels to the biopsy results yielded an AUC of 0.81 (0.71–0.94). (4) Combining the endobiliary biopsy results, SEMS tissues, and CA 19–9 levels yielded the best diagnostic accuracy, with an AUC of 0.90 (0.83–0.98). Detection of biliary obstruction using the combination strategy was better than the diagnostic results based on biopsy alone according to recent 3-year data. Our study suggested that SEMS removal could help establish a diagnosis of suspected malignant biliary obstruction.

Background/Aims Gastrointestinal bleeding (GIB) risk for non-vitamin K antagonist oral anticoagulants (NOACs) compared with warfarin is largely unknown. We aimed to determine the risk of overall and post-polypectomy GIB for NOACs and warfarin. Methods Using the Korean National Health Insurance database, we created a cohort of patients who were newly prescribed NOACs or warfarin between July 2015 and December 2017 using propensity score matching (PSM). Kaplan-Meier analysis with log-rank test was performed to compare the risk of overall and post-polypectomy GIB between NOACs (apixaban, dabigatran, and rivaroxaban) and warfarin. Post-polypectomy GIB was defined as bleeding within 1 month after gastrointestinal endoscopic polypectomy. Results Out of 234,206 patients taking anticoagulants (187,687 NOACs and 46,519 warfarin), we selected 39,764 pairs of NOACs and warfarin users after PSM. NOACs patients showed significantly lower risk of overall GIB than warfarin patients (log-rank P

Percutaneous endoscopic gastrostomy (PEG) is a common method for providing long-term enteral nutrition to patients. PEG tube placement and removal are relatively safe; generally, a PEG tube can be removed using gentle traction, and excessive bleeding is rare. The over-the-scope clip system is a new device that can be used for gastrointestinal hemostasis and for closing gastrointestinal fistulae. In the present case, a 68-year-old male patient had to remove the PEG tube because of persistent leakage around the PEG tube. Although it was gently removed using traction, incessant bleeding continued, with a Rockall score of 5 points, even after hemocoagulation was attempted. An over-the-scope clip device was used to achieve hemostasis and fistula closure.

A novel lipase (triacylglycerol acylhydrolase, EC 3.1.1.3) was discovered from Korean chestnut (Castanea crenata). The lipase was isolated and purified by ammonium sulfate precipitation and a fast protein liquid chromatography system equipped with HiTrap DEAE-Sepharose Fast Flow, HiTrap Q-Sepharose Fast Flow, and HiPrep Sephacryl S-100 Hi-Resolution columns. The purified C. crenata lipase showed a 15.8% yield, purification fold number of 465.8, and specific activity against triolein of 88.5 mU/mg. The enzyme exhibited hydrolytic activity toward tributyrin, trilaurin, and triolein, and was maximally active at pH 8.0 and 35 °C, with triolein used as the substrate. The activation energy (Ea) and deactivation energy (Ed) of triolein hydrolysis were 38.41 and 83.35 kJ/mol, respectively. In the enzyme kinetic study, Vmax, Km, and kcat were 110.58 mU/mg, 0.11 mM, and 0.221 min−1, respectively. The relatively low Km value indicated that the lipase has high affinity for its substrate. Moreover, Mg2+ and Ca2+ increased the lipase activity to 115.4% and 108.3%, respectively. The results of peptide fingerprinting revealed that the C. crenata lipase with a molecular weight of 33.3 kDa was structurally similar to the mannose-binding lectin of the jacalin-related lectin domain superfamily, implying that it has potential as a therapeutic agent for use in the biomedical industry.

Tracking the flow of charge in reacting molecules may provide key insight into reaction mechanisms, but is particularly challenging in liquid solutions. Here the authors, by analyzing the isotropic and anisotropic scattering signal in femtosecond time resolved X-ray liquidography, determine the charge localization and structural changes during photodissociation of the triiodide anion I3 -

Background/Aims Recent reports suggest that the biliary self-expandable metallic stent (SEMS) is highly effective for maintaining hemostasis when endoscopic hemostasis fails in endoscopic retrograde cholangiopancreatography (ERCP)-related bleeding. We compared whether temporary SEMS offers better efficacy than angioembolization for refractory immediate ERCP-related bleeding. Methods Patients who underwent SEMS placement or underwent angioembolization for bleeding control in refractory immediate ERCP-related bleeding were included in the retrospective analysis. We evaluated the hemostasis success rate, severity of bleeding, change in hemoglobin levels, amount of transfusion, and delay to the start of hemostasis. Results A total of 27 patients with SEMS and 13 patients who underwent angioembolization were enrolled. More transfusions were needed in the angioembolization group (1.0±1.4 units vs. 2.5±2.0 units; p=0.034). SEMS failure was successfully rescued by angioembolization. The partially covered SEMS (n=23, 85.1%) was generally used, and the median stent-indwelling time was 4 days. The mean delay to the start of angioembolization was 95.2±142.9 (range, 9–491) min. Conclusions Temporary SEMS had similar results to those of angioembolization (96.3% vs. 92.3%; p=0.588). Immediate SEMS insertion is considered a bridge treatment modality for immediate refractory ERCP-related bleeding. Angioembolization still has a role as rescue therapy when SEMS does not work effectively.

This paper presents a quantum search algorithm (QSA) for weighted solutions. In a QSA, the final quantum state has an equal probability of solutions. However, solutions should have different probabilities in specific problems, such as dynamic spectrum management (DSM). We propose a method to make differences with probability in accordance with rewards for each solution, and present an application to DSM. The proposed algorithm has some error terms for the final quantum state, and we provide the error terms in accordance with the number of iterations. In addition, we present the simulation results of the proposed algorithm compared with a classical exact algorithm and QSA. The proposed algorithm has a lower complexity and relative difference than the classical exact algorithm. Furthermore, the proposed algorithm has a higher performance than the QSA in specific cases.

A linear system can be solved more efficiently by quantum computing. However, previously known quantum algorithms provide only a quantum state as the solution; consequently, we cannot obtain the value of each component of the solution. We propose a method to extract the component values of the solution, and we present an application to linear multiple-input multiple-output (MIMO) detections. In the proposed algorithm, we demonstrate a concrete method that applies a quantum linear system algorithm (QLSA) when the components of a solution have binary variables, quaternary variables, or roots of a complex number. Whereas the conventional method requires an additional process to read out the values of the components, the proposed algorithm does not need any post-procedure. Instead, our method uses a QLSA iteratively, and the number of uses is logarithmic in the size of the linear system. Thus, our method maintains the runtime with the quantum advantage, but the conventional approach increases the runtime significantly. Furthermore, the application of the proposed method shows that quantum computing can collaborate with communication systems for large-scale MIMO systems.

The recurrence rate of choledocholithiasis in the general population has been reported to exceed 10%. The incidence of cholelithiasis was reported to be higher in patients following gastrectomy than that in the general population. However, there is no study for recurrent choledocholithiasis incidence in patients following gastrectomy. This study aimed to evaluate the recurrence rate of choledocholithiasis and identify risk factors for recurrent choledocholithiasis in patients following gastrectomy. A retrospective analysis was performed on patients with gastrectomy history who underwent choledocholithiasis removal in Kyungpook National University Hospital between January 2011 and December 2019. Choledocholithiases were treated by endoscopic retrograde cholangiopancreatography (ERCP) (n = 41) or percutaneous transhepatic biliary drainage (PTBD) (n = 90). The gastrectomy type was classified as subtotal gastrectomy with Billroth I (18.3%), Billroth II (45.0%), and total gastrectomy with Roux-en-Y (36.6%). During a median follow-up period of 31.5 (range, 6–105) months, choledocholithiasis recurrence was noted in 19 of 131 patients (14.5%). In subgroup analysis, the ERCP group (24.4%) had higher choledocholithiasis recurrence than the PTBD group (10.0%). Stone removal modality (ERCP), no use of balloon sphincteroplasty, and the presence of periampullary diverticulum were significant risk factors for recurrent choledocholithiasis. In multivariate analysis, ERCP (hazard ratio (HR), 3.597; 95% confidence interval (CI): 1.264–10.204) CBD stricture (HR, 3.823; 95% CI: 1.118–13.080) and no use of balloon sphincteroplasty (HR, 4.830; 95% CI: 1.669–13.889) were risk factors for recurrent choledocholithiasis following stone removal. The incidence of CBD stones in patients who underwent gastrectomy is similar to that of the general population. ERCP, CBD stricture, and no use of balloon sphincteroplasty are potential risk factors for recurrent CBD stones following gastrectomy. When we consider PTBD disadvantages, the ERCP procedure with active use of balloon sphincteroplasty is recommended to decrease recurrent CBD stones.

Abstract In this research, we study soft-output decoding of polar codes. Two representative soft-output decoding algorithms are belief propagation (BP) and soft cancellation (SCAN). The BP algorithm has low latency but suffers from high computational complexity. On the other hand, the SCAN algorithm, which is proposed for reduced complexity of soft-output decoding, achieves good decoding performance but suffers from long latency. These two algorithms are suitable only for two extreme cases that need very low latency (but with high complexity) or very low complexity (but with high latency). However, many practical systems may need to work for the moderate cases (i.e., not too high latency and not too high complexity) rather than two extremes. To adapt to the various needs of the systems, we propose a very flexible soft-output decoding framework of polar codes. Depending on which system requirement is most crucial, the proposed scheme can adapt to the systems by controlling the level of parallelism. Numerical results demonstrate that the proposed scheme can effectively adapt to various system requirements by changing the level of parallelism.

Background/Aims: Recently, the European Society of Gastrointestinal Endoscopy (ESGE) proposed criteria for “difficult biliary cannulation” during endoscopic retrograde cholangiopancreatography (ERCP). This study aimed to investigate the clinical relevance of the ESGE criteria from the perspective of post-ERCP pancreatitis (PEP). Methods: An ERCP database was prospectively maintained between November 2014 and December 2015 across six teaching hospitals in South Korea. The ESGE criteria (biliary cannulation time, the number of cannulation attempts, and inadvertent pancreatic duct [PD] manipulation) were recorded in this database as well as other technical factors. Logistic regression analysis was used to identify risk factors for PEP. Then, the PEP prediction model was investigated using decision tree analysis. Results: We analyzed 1,067 consecutive patients with naïve papilla. The overall rate of PEP was 6.6%. Multivariate analysis revealed that female sex (odds ratio [OR], 1.860; 95% confidence interval [CI], 1.124 to 3.078), a selective biliary cannulation duration >5 minutes (OR, 3.282; 95% CI, 1.641 to 6.566), and inadvertent PD manipulation (OR, 2.614; 95% CI, 1.480 to 4.617) were significant factors affecting PEP. Decision tree analysis revealed that biliary cannulation time (χ2=49.857, p5 minutes, and >5 minutes with inadvertent PD manipulation, respectively. Conclusions: Biliary cannulation time and inadvertent PD manipulation could be relevant indicators of PEP, and 5 minutes might be used as a cutoff value for the implementation of the rescue cannulation technique.

Gastrointestinal arteriovenous malformation (AVM) is reported as one of the possible causes of intestinal bleeding, and its occurrence in the rectum is rare. We report the case of a rectal AVM patient who experienced uncommon symptoms of anal pain and tenesmus and was treated successfully with percutaneous transarterial ethanol sclerotherapy. The patient underwent routine colonoscopy with biopsy at the time of visit; however, an accurate diagnosis was difficult. Subsequent contrast-enhanced computed tomography (CT) and angiography revealed a rectal AVM emerging from the distal inferior mesenteric artery with engorged superior rectal veins. The feeding artery was catheterized, and concurrent transarterial sclerotherapy with 80% ethanol was performed. There was no major complication related to the procedure. Disappearance of AVM nidus and improvement of associated venous congestion were shown by follow-up CT. There was no recurrence of symptoms after 10 months of clinical observation. Transarterial ethanol sclerotherapy is safe and effective in treating rectal AVM and can be considered as one of the nonsurgical treatment options.

Abstract Background The association between breakfast skipping and abnormal metabolic outcomes remains controversial. A comprehensive study with various stratified data is required. Objective The aim of this study was to investigate the relationship between abnormal metabolic outcomes and breakfast skipping by sex, age, and work status stratification. Methods We used data from the Korea National Health and Nutrition Examination Surveys from 2013 to 2018. A total of 21,193 (9022 men and 12,171 women) participants were included in the final analysis. The risk of metabolic outcomes linked to breakfast skipping was estimated using the negative binomial regression analysis by sex, work status, and age stratification. Results A total of 11,952 (56.4%) participants consumed breakfast regularly. The prevalence of abnormal metabolic outcomes was higher among those with irregular breakfast consumption habits. Among young male workers, negative binomial regression analysis showed that irregular breakfast eaters had a higher risk of abnormal metabolic outcomes, after adjusting for covariates (odds ratio, 1.15; 95% confidence interval, 1.03–1.27). Conclusions The risk of abnormal metabolic outcomes was significant in young men in the working population. Further studies are required to understand the association of specific working conditions (working hours or shift work) with breakfast intake status and the risk of metabolic diseases.

Various indigenous yeasts were isolated and obtained from flowers in the Republic of Korea, and their distribution and species diversity were studied. Seventy-seven flowers were collected from 25 areas in Korea, and 502 yeast strains were isolated from these flowers. A total of 50 species were identified by comparing large subunit rDNA gene sequence homology with the type strains of yeasts. The analysis of yeast distribution showed that the dominant yeast species were Aureobasidium pullulans, A. leucospermi, and Filobasidium magnum in each region and flower samples. Except for the above three yeast species, no species of yeasts showed any meaningful distribution among the habitat regions and sources. In conclusion, 50 species of indigenous yeasts were obtained from flowers that can be used as industrial resources, and the data could be used for further research on yeast diversity and interactions between yeast and its host.

ERCP is the standard treatment for common bile duct stones. On the other hand, 10-15% of cases involve intractable common bile duct stones, which cannot be treated by conventional biliary sphincterotomy with a stone retrieval method. Large bile duct stones are typically managed by mechanical lithotripsy and endoscopic papillary large balloon dilatation. Peroral cholangioscopy techniques can be applied if this technique fails. In the present case, a 67-year-old woman had a large common bile duct stone that could not be retracted using the conventional ERCP stone extraction method. The common bile duct stone was eventually removed by direct peroral upper gastrointestinal endoscopy and a polypectomy snare.

Although infected pancreatic necrosis can develop as a result of rare conditions involving trauma, surgery, and systemic infection with an uncommon pathogen, it usually occurs as a complication of pancreatitis. Early phase of acute pancreatitis can be either edematous interstitial pancreatitis or necrotizing pancreatitis. The late complications of pancreatitis can be divided into pancreatic pseudocyst due to edematous interstitial pancreatitis or walled-off necrosis due to necrotizing pancreatitis. During any time course of pancreatitis, bacteremia can provoke infection inside or outside the pancreas. The patients with infected pancreatic necrosis may have fever, chills, and abdominal pain as inflammatory symptoms. These specific clinical presentations can differentiate infected pancreatic necrosis from other pancreatic diseases. Herein, I report an atypical case of infected pancreatic necrosis in which abdominal pain, elevation of white blood cell, and fever were not found at the time of admission. Rather, a 10-kg weight loss (from 81 to 71 kg) over 2 months nearly led to a misdiagnosis of pancreatic cancer. The patient was finally diagnosed based on endoscopic ultrasound-guided fine-needle aspiration. This case highlights that awareness of the natural course of pancreatitis and infected pancreatic necrosis is important. In addition, endoscopic ultrasound-guided fine-needle aspiration should be recommended for the diagnosis and treatment of indeterminate pancreatic lesions in selected patients.

Abstract This paper introduces two effective techniques to reduce the decoding complexity of turbo product codes (TPC) that use extended Hamming codes as component codes. We first propose an advanced hard-input soft-output (HISO) decoding algorithm, which is applicable if an estimated syndrome stands for double-error. In conventional soft-input soft-output (SISO) decoding algorithms, 2 p (p: the number of least reliable bits) number of hard decision decoding (HDD) operations are performed to correct errors. However, only a single HDD is required in the proposed algorithm. Therefore, it is able to lower the decoding complexity. In addition, we propose an early termination technique for undecodable blocks. The proposed early termination is based on the difference in the ratios of double-error syndrome detection between two consecutive half-iterations. Through this early termination, the average iteration number is effectively lowered, which also leads to reducing the overall decoding complexity. Simulation results show that the computational complexity of TPC decoding is significantly reduced via the proposed techniques, and the error correction performance remains nearly the same in comparison with that of conventional methods.

Background/Aims: Few studies have addressed the relationship between the occurrence of adverse events (AEs) in endoscopic retrograde cholangiopancreatography (ERCP) and hospital case volume or endoscopist’s experience with inconsistent results. The aim of our study was to investigate the impact of hospital case volume and endoscopist’s experience on the AEs associated with ERCP and to analyze patient- and procedure-related risk factors for post-ERCP AEs. Methods: From January 2015 to December 2015, we prospectively enrolled patients with naïve papilla who underwent ERCP at six centers. Patient- and procedure-related variables were recorded on data collection sheets at the time of and after ERCP. Results: A total of 1,191 patients (median age, 71 years) were consecutively enrolled. The overall success rate of biliary cannulation was 96.6%. Overall, 244 patients (20.5%) experienced post-ERCP AEs, including pancreatitis (9.0%), bleeding (11.8%), perforation (0.4%), cholangitis (1.2%), and others (0.9%). While post-ERCP pancreatitis (PEP) was more common when the procedure was performed by less experienced endoscopists, bleeding was more common in high-volume centers and by less experienced endoscopists. Multivariate analysis showed that a less experience in ERCP was significantly associated with PEP (odds ratio [OR], 1.630; 95% confidence interval [CI], 1.050 to 2.531; p=0.030) and post-ERCP bleeding (OR, 1.439; 95% CI, 1.003 to 2.062; p=0.048). Conclusions: Our study demonstrated that overall AEs following ERCP were associated with the experience of the endoscopist. To minimize post-ERCP AEs, rigorous training with a sufficient case volume is required, and treatment strategies should be modified according to the endoscopist’s expertise.

We propose a novel method to calculate the propagation from a geostationary orbit (GEO) satellite to a ground station considering dispersive and inhomogeneous atmospheric environments with an actual satellite parabolic reflector antenna. The proposed simulation method is based on the hybrid numerical techniques including physical optics (PO), the 3-dimensional (3-D) ray tracing technique, and geometrical optics (GO). The electromagnetic propagation from an actual GEO satellite parabolic reflector antenna to a ground station at Seoul, Korea is calculated using PO. Reflections and refractions at the boundaries of the stratified refractive index model for the atmosphere are then calculated by the ray tracing approach and GO to take into account inhomogeneous atmospheric environments. Our method is verified by comparing with the results with the prediction method of rain attenuation given in ITU-R P.618-13 and the unified model. The comparison generally shows a good agreement. Atmospheric attenuation and boresight errors from a GEO satellite to a ground station are calculated and discussed. As a result of the calculations, when the rainfall rate is 26.19 mm/h, the atmospheric attenuation from a GEO satellite (COMS-1) to a ground station at Seoul, Korea is 12.1621 dB and the boresight error is 0.0336 degrees.

Endobiliary radiofrequency ablation (RFA) is a procedure performed widely to induce locoregional tumor control by the transfer of thermal energy to the lesion and subsequent tumor necrosis. A 72-year-old male with a prior history of acute calculous cholangitis and perforated cholecystitis was admitted to the Kyungpook National University Hospital complaining of fever and nausea. He had an indwelling percutaneous transhepatic gallbladder drainage (PTGBD) catheter from the previous episode of perforated cholecystitis. An abdominal CT scan showed marked dilation of both the intrahepatic and extrahepatic bile ducts. Common bile duct cancer was confirmed histologically after an endobiliary biopsy. A surgical resection was considered to be the initial treatment option. During open surgery, multiple metastatic nodules were present in the small bowel mesentery and anterior abdominal wall. Resection of the tumor was not feasible, so endobiliary RFA was performed prior to biliary stenting. Cholecystectomy was required for the removal of the PTGBD catheter, but the surgical procedure could not be performed due to a cystic ductal invasion of the tumor. Instead, chemical ablation of the gallbladder (GB) with pure ethanol was performed to breakdown the GB mucosa. Palliative treatment for a biliary obstruction was achieved successfully using these procedures. In addition, a PTGBD catheter was removed successfully without significant side effects. As a result, an improvement in the patient’s quality of life was accomplished.

It is important to determine the position of the receiver (Rx) coils in wireless power transfer (WPT) system, and to control the power transmitted to the Rx coil based on this result. In particular, in a situation where there is no feedback between the primary side and the secondary side, it is difficult to control the received power because the information is limited. In this paper, a method for determining the position of the Rx coils and controlling the received power using limited parameters in a feedback-free WPT system is proposed. The proposed method is verified by constructing a 4×2 WPT system, and it is validated that the simulation result and the experimental result are consistent well. Furthermore, arbitrary power can be transmitted to the Rx coil based on the result of the position of the Rx coil. The experiment is conducted by transmitting about 1W to Rx 1 and Rx 2, and the efficiency for Rx 1 is about 32.93%, Rx 2 is 25.03%, and the overall efficiency is confirmed to be 57.96%.

Bone is a dynamic tissue that maintains homeostasis with a balance of osteoclasts for bone resorption and osteoblasts for bone formation. Women are deficient in estrogen after menopause, which promotes bone resorption due to excessive activity of osteoclasts, leading to osteoporosis. TH (also known as dandelion) is native to warm regions and has traditionally been used to treat gynecological diseases and inflammation. Menopause is a major cause of osteoporosis as it causes abnormal activity of osteoclasts, and various studies have shown that anti-inflammatory drugs have the potential to treat osteoporosis. We analyzed the effect of TH on osteoclast differentiation and the relevant mechanisms using RANKL. After administration of TH in a menopause-like rat model in which ovariectomy of the was rats carried out, changes in bone microstructure were analyzed via micro-CT, and the antiosteoporosis effect of TH was verified by a histological analysis. In addition, the pharmacological effects of TH in an animal model of osteoporosis were compared and analyzed with osteoporosis medications (17β-estradiol (E2) and alendronate (ALN)). TH significantly inhibited the initial osteoclast differentiation via the NFATc1/c-Fos mechanism. In addition, bone density in the femur of osteoporotic rats was increased, and the expression of osteoclast-related factors in the serum and tissues was controlled. The results of this study provide objective evidence of the inhibitory effect of TH on osteoclastogenesis and OVX-induced bone loss.

Background and Objectives: Acute peripancreatic fluid collection (APFC) is an acute local complication of acute pancreatitis (AP) according to the revised Atlanta classification. Sometimes APFC resolves completely, sometimes it changes into a pseudocyst or walled-off necrosis (WON), so called late complications. The aim of this study is to investigate the natural course of APFC detected on early computed tomography (CT) in moderately severe (MSAP) or severe AP (SAP). Materials and Methods: From October 2014 to September 2015, patients with MSAP or SAP were enrolled if there was APFC within 48 h of onset on imaging studies at six medical centers. The status of fluid collection was followed 4–8 weeks after onset. Initial laboratory findings, CT findings and clinical scoring systems were analyzed. Results: A total of 68 patients were enrolled and APFC was completely resolved in 32 (66.7%) patients in the MSAP group and 9 (34.6%) in the SAP group. Patients with a high bedside index for severity in acute pancreatitis (BISAP) score (≥3 points) were common in the SAP group. C-reactive protein (CRP) after 48 h from admission and BUN level were also high in the SAP group. In multivariate analysis, BISAP score (≥3 points), elevation of CRP after 48 h (≥150 mg/L) and nasojejunal feeding after 48 h were risk factors for the development of late complications. Conclusions: Spontaneous resolution of APFC was more common in MSAP group and APFC can be changed to pseudocyst or WON in patients with elevated BISAP score, CRP level after 48 h, and non-improved abdominal pain.

Zoonotic avian influenza viruses pose severe health threats to humans. Of several viral subtypes reported, the low pathogenic avian influenza H7N9 virus has since February 2013 caused more than 1,500 cases of human infection with an almost 40% case-fatality rate. Vaccination of poultry appears to reduce human infections. However, the emergence of highly pathogenic strains has increased concerns about H7N9 pandemics. To develop an efficacious H7N9 human vaccine, we designed vaccine viruses by changing the patterns of N-linked glycosylation (NLG) on the viral hemagglutinin (HA) protein based on evolutionary patterns of H7 HA NLG changes. Notably, a virus in which 2 NLG modifications were added to HA showed higher growth rates in cell culture and elicited more cross-reactive antibodies than did other vaccine viruses with no change in the viral antigenicity. Developed into an inactivated vaccine formulation, the vaccine virus with 2 HA NLG additions exhibited much better protective efficacy against lethal viral challenge in mice than did a vaccine candidate with wild-type (WT) HA by reducing viral replication in the lungs. In a ferret model, the 2 NLG-added vaccine viruses also induced hemagglutination-inhibiting antibodies and significantly suppressed viral replication in the upper and lower respiratory tracts compared with the WT HA vaccines. In a mode of action study, the HA NLG modification appeared to increase HA protein contents incorporated into viral particles, which would be successfully translated to improve vaccine efficacy. These results suggest the strong potential of HA NLG modifications in designing avian influenza vaccines.

Purpose: To compare filter tilt and filter jumping during Option inferior vena cava (IVC) filter deployment with 3 different wires techniques using a 3-dimensional (3D) printing vena cava phantom. Materials and methods: An IVC 3D printed vena cava phantom was made from a healthy young male’s computed tomographic data. Option IVC filters were deployed with 3 different wires: i) original push wire, ii) hydrophilic stiff wire, and iii) bent stiff wire. Right internal jugular and right femoral access were used 5 times with each wire. Filter tilt angle, tilt ratio, jumping, and tip abutment to the IVC wall were analyzed. Results: The transfemoral approach with original push wire had significantly higher tilt angle than did the transjugular approach (6.1˚ ± 1.9 vs. 3.5˚ ± 1.3, p = 0.04). Mean tilt ratio was significantly lower with the bent wire with transfemoral access (0.49 ± 0.13 vs. 0.78 ± 0.18 [original push-wire] and 0.67 ± 0.08 [stiff wire], p = 0.019). The ratio was lower also with original push wire with transjugular access (0.34 ± 0.19 vs. 0.57 ±0.11 [stiff wire] and 0.58 ±0.17 [bent wire], p = 0.045). Filter jumping occurred more often with the transjugular approach with original push wire than with stiff or bent-wire delivery. Filter tip abutment to the IVC wall occurred only with the transfemoral approach. Conclusions: Bent wire with transfemoral access and original push wire with transjugular access had lower filter tilt ratio at Option IVC filter deployment. However, filter jumping was common using the original push wire with transjugular access.

Purpose: To review a single-center experience of percutaneous biliary recanalization for liver transplantation-related benign biliary stricture, particularly focusing on the technical aspect Method: Twenty-three recipients of liver transplantation (LT) with 27 benign biliary strictures underwent percutaneous recanalization using a step-by-step technique from June 2017 to March 2020. The step-by-step technique includes a hairy wire or an usual 0.035-inch wire passage, a coaxial system, supporting catheters of various shapes and wires, and an extraluminal passage. The success rate of percutaneous biliary recanalization, degree of stricture, interval between LT and biliary recanalization, procedure time, number of sessions, and recanalization techniques were analyzed. Results: Among the 27 lesions, 26 (96 %) were successfully recanalized using a percutaneous approach without major complications. Of the 27 lesions, 8 were complete obstructions and 19 were partial obstructions. Consequently, the average interval between LT and biliary recanalization was 28.8 ± 42.7 months (range, 2–192 months). The average procedure time was 50 ± 65 min (range, 8–345 min). The average number of sessions was 1.4 ± 1 (range, 1–6). The case distribution for the used recanalization techniques was as follows: twelve cases utilized step 1, 10 utilized step 2, 4 utilized step 3, and only 1 case utilized step 4. The complete obstruction group required a more advanced technique and spent more recanalization time than the partial obstruction group. Conclusions: The step-by-step percutaneous biliary recanalization technique had a high success rate without major complications. According to the patient’s biliary anatomy appropriate selection of an angled 5-Fr support catheter and wire is essential in increasing the recanalization success rate.

The current experimental study examined whether different degrees of immersive and interactive experience made a difference in users’ perceptions and intention to adopt a novel VR-based MR training system. In this paper, virtual reality was used as an educational technology that allowed users to virtually rotate 3-D objects and helped to enhance their spatial ability, which would be particularly useful in future careers in STEM. A 2 (display) $\times \,\, 2$ (controller) $\times \,\, 2$ (gender) experimental design was conducted. Researchers used a 2-D monoscopic display and a stereoscopic display to manipulate two different conditions of immersion, while a computer mouse and a hand-held controller were applied to measure the effects from two different levels of interactivity. Gender was examined due to prior research suggesting that males were better at MR tasks than females. The dependent variables were various perceptions and behavioral intentions developed from relevant theories in technology acceptance. The results showed that users’ positive perceptions and intention to use the novel MR system were amplified whenever better immersive and interactive experiences were provided simultaneously, or when the inferior immersive and interactive experiences were offered at the same time. Females under a better immersive environment perceived better feelings of enjoyment, confirmation, satisfaction, and behavioral intention, compared with their male counterparts. Theoretical contributions in perceptions and use intention of educational technology, with a specific focus on VR, were discussed. Practical implications for developers of educational technology and K-12/college educators were provided.

This paper presents a technique for reducing the decoding complexity of block turbo code with an extended Hamming code as a component code. In conventional decoding algorithms, when an input vector has a zero syndrome, complexity can be reduced by using the hard-input soft-output (HISO) algorithm. Although sufficient error correction can be achieved using hard decision decoding (HDD) of a component code, conventional methods have used the soft-input soft-output (SISO) algorithm for input vectors with a single error. However, when HDD is applied to all input vectors in which the syndrome is detected as a single error, performance loss occurs owing to the occasional presence of input vectors with triple errors. To solve this problem, we used two criteria for distinguishing between instances of single and triple errors. We maximized the applied rates of the HDD-based HISO algorithm depending on whether the criteria were satisfied. The SISO algorithm was applied when the two criteria were not met. In this case, the number of HDD usages can be reduced to half by removing duplicates or unnecessary candidate codewords. Simulation results show that the proposed algorithm can considerably reduce decoding complexity without performance loss compared with conventional algorithms.

Road surface detection is important for safely driving autonomous vehicles. This is because the knowledge of road surface conditions, in particular, dry, wet, and snowy surfaces, should be considered for driving control of autonomous vehicles. With the rise of deep learning technology, road surface detection methods using deep neural networks (DNN) have been widely used for developing road surface detection algorithms. To apply DNN in road surface detection, the dataset should be large and well-balanced for accurate and robust performance. However, most of the images of road surfaces obtained through usual data collection processes are not well-balanced. Most of the collected surface images tend to be of dry surfaces because road surface conditions are highly correlated with weather conditions. This could be a challenge in developing road surface detection algorithms. This paper proposes a method to balance the imbalanced dataset using CycleGAN to improve the performance of a road surface detection algorithm. CycleGAN was used to artificially generate images of wet and snow-covered roads. The road surface detection algorithm trained using the CycleGAN-augmented dataset had a better IoU than the method using imbalanced basic datasets. This result shows that CycleGAN-generated images can be used as datasets for road surface detection to improve the performance of DNN, and this method can help make the data acquisition process easy.

This paper proposes the algorithm to control the current ratio of the transmitting (Tx) coils for proper power distribution to the two receiving (Rx) coils in wireless power transfer (WPT) system. The proposed algorithm assumes that each Rx coil appears at different times to consider the situation where multiple users request power transmission as practically as possible. That is, suppose the second Rx coil enters the charging space later than the first Rx coil. When each coil enters the charging space, only the Tx coil is used to obtain the value required for calculation. Using the obtained result, the optimized Tx coil current is calculated by the proposed algorithm and proper power distribution to both Rx coils is achieved. Three Tx coils and two Rx coils are constructed using the ANSYS MAXWELL simulation tool. As a result of applying the proposed algorithm, it was confirmed that a similar level of power was transmitted between 40∼60%, respectively. The sum of the power transmitted to the two Rx coils also appeared as more than 75%.

Abstract A modified message propagation algorithm is proposed for a low-complexity decoder of low-density parity-check (LDPC) codes, which controls the information propagated from variable and check nodes.The proposed threshold-based node deactivation for variable nodes and zero-forcing scheme for check nodes remarkably reduce decoding complexity required for similar error performance. In the proposed scheme, different thresholds, which are determined from the base matrix of the LDPC codes, are applied for each type of variable node. In addition, thresholds for deactivating variable nodes are increased while the decoding process is operated for a reduction in decoding complexity without early error floor, which is a drawback of the conventional threshold-based deactivation scheme. Simulation results show that the proposed scheme enables normalized min-sum decoders to decode successfully with less complexity than the conventional threshold-based deactivating scheme.

In this study, we fabricated a nanoporous oxide layer by anodization to improve corrosion resistance of type 304 stainless steel (SS) gas tungsten arc weld (GTAW). Subsequent heat treatment was performed to eliminate any existing fluorine in the nanoporous oxide layer. Uniform structures and compositions were analyzed with field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD) measurements. The corrosion resistance of the treated SS was evaluated by applying a potentiodynamic polarization (PDP) technique and electrochemical impedance spectroscopy (EIS). Surface morphologies of welded SS with and without treatment were examined to compare their corrosion behaviors. All results indicate that corrosion resistance was enhanced, making the treatment process highly promising.

In quantum communication systems, quantum error-correcting codes (QECCs) are known to exhibit improved performance with the use of error-free entanglement bits (ebits). In practical situations, ebits inevitably suffer from errors, and as a result, the error-correcting capability of the code is diminished. Previous studies have proposed two different schemes as a solution. One study uses only one QECC to correct errors on the receiver side (i.e., Bob) and sender side (i.e., Alice). The other uses different QECCs on each side. In this paper, we present a method to correct errors on both sides by using single nonadditive entanglement-assisted codeword stabilized quantum error-correcting code (EACWS QECC). We use the property that the number of effective error patterns decreases as much as the number of ebits. This property results in a greater number of logical codewords using the same number of physical qubits.

The effect of scintillator particle size on high-resolution X-ray imaging was studied using zinc tungstate (ZnWO4) particles. The ZnWO4 particles were fabricated through a solid-state reaction between zinc oxide and tungsten oxide at various temperatures, producing particles with average sizes of 176.4 nm, 626.7 nm, and 2.127 μm; the zinc oxide and tungsten oxide were created using anodization. The spatial resolutions of high-resolution X-ray images, obtained from utilizing the fabricated particles, were determined: particles with the average size of 176.4 nm produced the highest spatial resolution. The results demonstrate that high spatial resolution can be obtained from ZnWO4 nanoparticle scintillators that minimize optical diffusion by having a particle size that is smaller than the emission wavelength.

Background/AimsBacillus Licheniformis, a probiotic used in the treatment of diarrhea, has been shown to suppress the growth of pathologic bacteria. This study was performed to assess the therapeutic efficacy and safety of Zhengchangsheng® (Bacillus Licheniformis) in comparison with another probiotic, Bioflor® (Saccharomyces Boulardii) for the treatment of diarrhea.MethodsPatients with diarrhea (n=158) were randomized to receive Zhengchangsheng® or Bioflor® for 5 days. The existence or non-existence of formed feces, changes in daily stool frequency, improvement of subjective symptoms, and changes in the severity of diarrhea were compared.ResultsOf the 158 full analysis set (FAS) patient population, 151 patients comprised the per protocol (PP) analysis. The rates of recovered to formed feces in the Bacillus and Saccharomyces groups were 91.0% vs. 95.0% in the FAS (P=0.326) and 90.5% vs. 96.1% in the PP analysis (P=0.169), respectively. The mean duration of diarrhea changing to formed feces was 3.15±1.10 days in the Bacillus group and 3.22±1.01 in the Saccharomyces group (P=0.695, FAS). The frequency of defecation, subjective symptoms, and degree of severe diarrhea were improved in both groups, however, there were no statistically significant differences between the 2 groups. Analysis of the 95% confidence intervals for the differences in the rate of recovery to formed feces between the 2 groups met the criteria for non-inferiority of Bacillus compared to Saccharomyces. No significant adverse events were observed during the study period.ConclusionsZhengchangsheng® is not inferior to Bioflor® in therapeutic efficacy and is a safe and useful therapeutic agent for the treatment of diarrhea.

Influenza A virus (IAV) can infect avian and mammalian species, including humans. The genome nature of IAVs may contribute to viral adaptation in different animal hosts, resulting in gene reassortment and the reproduction of variants with optimal fitness. As seen again in the 2009 swine-origin influenza A H1N1 pandemic, pigs are known to be susceptible to swine, avian, and human IAVs and can serve as a 'mixing vessel' for the generation of novel IAV variants. To this end, the emergence of swine influenza viruses must be kept under close surveillance. Herein, we report the isolation and phylogenetic study of a swine IAV, A/swine/Korea/PL01/2012 (swPL01, H3N2 subtype). After screening nasopharyngeal samples from pigs in the Gyeongsangnam-do region of Korea from December 2011 to May 2012, we isolated the swPL01 virus and sequenced its all of 8 genome segments (polymerase basic 2, PB2; polymerase basic 1, PB1; polymerase acidic, PA; hemagglutinin, HA; nucleocapsid protein, NP; neuraminidase, NA; matrix protein, M; and nonstructural protein, NS). The phylogenetic study, analyzed with reference strains registered in the National Center for Biotechnology Information (NCBI) database, indicated that the swPL01 virus was similar to the North American triple-reassortant swine strains and that the HA gene of the swPL01 virus was categorized into swine H3 cluster IV. The swPL01 virus had the M gene of the triple-reassortant swine H3N2 viruses, whereas that of other contemporary strains in Korea was transferred from the 2009 pandemic H1N1 virus. These data suggest the possibility that various swine H3N2 viruses may co-circulate in Korea, which underlines the importance of a sustained surveillance system against swine IAVs.

Antiviral drugs are being used for therapeutic purposes against influenza illness in humans. However, antiviral-resistant variants often nullify the effectiveness of antivirals. Combined medications, as seen in the treatment of cancers and other infectious diseases, have been suggested as an option for the control of antiviral-resistant influenza viruses. Here, we evaluated the therapeutic value of combination therapy against oseltamivir-resistant 2009 pandemic influenza H1N1 virus infection in DBA/2 mice. Mice were treated for five days with favipiravir and peramivir starting 4 hours after lethal challenge. Compared with either monotherapy, combination therapy saved more mice from viral lethality and resulted in increased antiviral efficacy in the lungs of infected mice. Furthermore, the synergism between the two antivirals, which was consistent with the survival outcomes of combination therapy, indicated that favipiravir could serve as a critical agent of combination therapy for the control of oseltamivir-resistant strains. Our results provide new insight into the feasibility of favipiravir in combination therapy against oseltamivir-resistant influenza virus infection.