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This study aimed to measure the levels of airborne radon (Rn) and bioaerosols—culturable airborne bacteria (CAB) and culturable airborne fungi (CAF)—in South Korea’s residential environments, considering living conditions such as the number of ventilations, number of windows, floors, temperature, and relative humidity. These levels were evaluated for 32 houses of residents from the socially vulnerable class. Rn gas and bioaerosols were sampled twice: in fall and summer. A self-report survey gathered residents’ information on their general characteristics (daily residence time, heating and cooking type, cleaning and washing cycle, etc.) and health condition scores (0–100 points) on the day of sampling. The range of Rn levels was 0.43–7.439 pCi/L with a median of 0.70 pCi/L. The CAB levels were 239–488 colony-forming unit (CFU)/m3 with a median of 309 CFU/m3, and CAF levels were 174–366 CFU/m3 with a median of 233 CFU/m3. Thus, this study found that semi-basement residential indoor environments negatively affected Rn and bioaerosol levels, and living in such residences resulted in high health condition scores.

To evaluate commercial deep learning-based software for fully automated coronary artery calcium (CAC) scoring on non-electrocardiogram (ECG)-gated low-dose CT (LDCT) with different slice thicknesses compared with manual ECG-gated calcium-scoring CT (CSCT).This retrospective study included 567 patients who underwent both LDCT and CSCT. All LDCT images were reconstructed with a 2.5-mm slice thickness (LDCTCSCTFully automated CAC-scoring software with both CSCT and LDCT yielded excellent reliability and agreement with CSCT• Total Agatston scores and all vessels of CSCT

To demonstrate the relationship between spectral computed tomography (CT) measured iodine concentration and strength of aortic valvular calcification (AVC) in patients with aortic valve stenosis (AVS).A retrospective study was performed on patients who underwent transcatheter aortic valve replacement (TAVR) for symptomatic AVS and underwent both pre and postprocedural electrocardiogram gated CT scans using a spectral CT system. Preprocedural CT was used to evaluate the volume and iodine concentration (IC) in the AVC. Postprocedural CT data were used to calculate the volume reduction percentage (VRP) of AVC. Multiple linear regression analysis was used to identify the independent variables related to the VRP in AVCs.A total of 94 AVCs were selected from 22 patients. The mean volume and IC of the AVCs before TAVR were 0.37 mL ± 0.15 mL and 7 mg/mL ± 10.5 mg/mL, respectively. After TAVR, a median VRP of all 94 AVCs was 18.5%. Multiple linear regression analysis showed that the IC was independently associated with the VRP (coefficient = 1.64, p0.001). When an optimal IC cutoff point was set at 4 mg/mL in the assessment of a fragile AVC which showed the VRP was18.5%, the sensitivity was 63%; specificity, 91%; positive predictive value, 88%; and negative predictive value, 71%.When using spectral CT to prepare the TAVR, measuring the IC of the AVC may be useful to assess the probability of AVC deformity after TAVR.• A dual-layer detector-based spectral CT enables quantifying iodine of contrast media in the aortic valve calcification (AVC) on contrast-enhanced CT images. • The AVC including iodine of contrast media on contrast-enhanced CT image may have loose compositions, associated with the deformity of AVC after TAVR. • Measuring the iodine concentration in AVC may have the potential to assess the probability of AVC deformity, which may be associated with the outcome and complications after TAVR.2.

The purpose of this study was to determine the most efficient airborne asbestos filter for use in an HEPA negative air machines through filter performance testing. The filter classes applied conformed with ISO and European standard (EN 1822) regarding fractional efficiency by dust loading amount for filters, fractional efficiency for negative air machines, and consumption of electrical power at filter size 0.3 μm. Class H13 had the highest fractional efficiency among the three experimental filter classes by particle size, at face velocity of (1, 2, and 3) m/s. Melt-blown (MB) filters exhibited higher fractional performance than did glass-fiber filters at all particle sizes tested (0.3, 0.5, and 1.0 µm). The power consumption of glass-fiber filters was higher (at 10 m3/min) than that of melt-blown filters. Therefore, melt blown filters would be more cost-effective than glass fiber filters for use in HEPA negative air machines, for protection against airborne asbestos.Implications: Air cleaner and related systems were developed to control a variety of airborne pollutants in general indoor environments, but there was no certified system for focusing on asbestos fractional efficiency using filter tests. Class H13 had the highest fractional efficiency among the three experimental filter classes by particle size, at face velocity of (1, 2, and 3) m/s. Melt-blown filters exhibited higher fractional performance than did glass-fiber filters at all particle sizes tested (0.3, 0.5, and 1.0 µm). The power consumption of glass-fiber filters was higher (at 10 m3/min) than that of melt-blown filters.

The purpose of this study was to provide basic data on cognitive therapy and to improve social support programs for the elderly with dementia by identifying the difficulties they experienced in emotional communication by identifying how they recognized emotions in verbal reactions to facial expressions using Ekman’s photographs of facial expressions and comparing their responses with the general elderly population. There were 141 participants in this study. Data collection was conducted from 3 April 2019 to 30 June 2019 in Seoul, in the Gyeonggi-do and Gangwon-do provinces of South Korea. This study performed descriptive research in which subjects made participative decisions with their guardian through recruitment. The tools used in this study included a general characteristic questionnaire and the Ekman 6 facial expressions photographs tool, which underwent intensive validity studies. The collected data were analyzed using the R version 3.5.1 statistic computing platform. The ability of the elderly with dementia to associate verbal expressions with facial expressions differed from that of the general elderly population. The rates of correct associations of verbal expressions to facial expressions were similar across dementia grades. There was a significant difference in the proportion of correct associations between positive and negative emotions in the elderly with dementia compared to the general elderly population. In the elderly with dementia, pictures showing fear, anger, and disgust had higher wrong rates of incorrect answers than correct answers. The average score of elderly with dementia in associating verbal expressions with six facial expressions was 2.69, which was even lower when they were asked to associate verbal expressions with pictures showing facial expressions of anger or disgust. This study shows that elderly persons with dementia have difficulties identifying two negative emotions (anger, disgust) and find it much easier to identify a positive emotion of happiness represented by a smiling face. Since the ability of the elderly with dementia to interpret verbal expressions to facial expressions was different from that of the general elderly population, careful attention and consideration are needed to support and communicate emotions to the elderly with dementia.

We aimed to evaluate the performance of convolutional neural networks (CNNs) in the classification of coronavirus disease 2019 (COVID‐19) disease using normal, pneumonia, and COVID‐19 chest radiographs (CXRs). First, we collected 9194 CXRs from open datasets and 58 from the Korea University Anam Hospital (KUAH). The number of normal, pneumonia, and COVID‐19 CXRs were 4580, 3884, and 730, respectively. The CXRs obtained from the open dataset were randomly assigned to the training, tuning, and test sets in a 70:10:20 ratio. For external validation, the KUAH (20 normal, 20 pneumonia, and 18 COVID‐19) dataset, verified by radiologists using computed tomography, was used. Subsequently, transfer learning was conducted using DenseNet169, InceptionResNetV2, and Xception to identify COVID‐19 using open datasets (internal) and the KUAH dataset (external) with histogram matching. Gradient‐weighted class activation mapping was used for the visualization of abnormal patterns in CXRs. The average AUC and accuracy of the multiscale and mixed‐COVID‐19Net using three CNNs over five folds were (0.99 ± 0.01 and 92.94% ± 0.45%), (0.99 ± 0.01 and 93.12% ± 0.23%), and (0.99 ± 0.01 and 93.57% ± 0.29%), respectively, using the open datasets (internal). Furthermore, these values were (0.75 and 74.14%), (0.72 and 68.97%), and (0.77 and 68.97%), respectively, for the best model among the fivefold cross‐validation with the KUAH dataset (external) using domain adaptation. The various state‐of‐the‐art models trained on open datasets show satisfactory performance for clinical interpretation. Furthermore, the domain adaptation for external datasets was found to be important for detecting COVID‐19 as well as other diseases.

Background Ongoing studies are currently investigating the extent of surgical resection required for subsolid cancers. This study aimed to investigate the predictive factors related to recurrence in patients with clinical stage IA subsolid cancer who underwent either lobectomy or sublobar resection. Methods This was a prospective multicenter observational study conducted in eight qualifying university teaching hospitals between April 2014 and December 2016. A total of 173 patients with subsolid nodules pathologically confirmed to have primary lung adenocarcinoma and stage IA disease were included in the final analysis. All patients underwent lobectomy, segmentectomy, or wedge resection performed by experienced thoracoscopic surgeons at each site. The surgical procedure was chosen based on the decision of the surgeons involved. The primary endpoint was time to recurrence (TTR). Results The study population was 43.9% (76 of 173) male with a mean age of 60.7 years. During the median follow‐up period of 5.01 years, nine patients (5%) experienced disease recurrence. In the multivariable analysis, tumor size (size ≥2 cm) (hazard ratio: 73.717, 95% confidence interval [CI]: 3.635–895.036; p, Highlights This study aimed to investigate risk factors related to recurrence in patients with clinical stage IA subsolid cancer who underwent either lobectomy or sublobar resection.The main results showed excellent surgical outcomes regardless of surgical procedure, subsolid nodule subtype and solid component size.Our results validate subjects eligible for sublobar resection recommended by the NCCN 2020 guideline and provide surgeons with a rationale for choosing a less extensive surgical alternative for clinical stage IA adenocarcinomas observed as subsolid nodules without compromising patient outcomes.

This paper describes a new algorithm that independently manages braking and driving forces to improve the lateral stability of a vehicle equipped with independent drive motors on all wheels. In a similar way to previous research, the proposed algorithm controls yaw rate to improve lateral stability. However, unlike in previous research that only used differential braking, our algorithm controls both driving and braking forces on all four wheels independently to achieve the target yaw rate. The core contribution of this paper is the distribution logic that determines the braking and driving forces to apply at each wheel. To develop this distribution logic, we introduce the concept of yaw moment contour line. Using this concept, the optimal distribution strategy can be derived by considering yaw moment control performance, lateral movement performance, and deceleration minimization performance in eight different driving situations. Based on this strategy, we design a lateral stability control algorithm that is made up of a target yaw rate, a yaw moment controller, and a distributor. Simulations were performed to investigate the performance of the proposed algorithm using MATLAB/Simulink and the CarSim vehicle dynamics software. The simulation results show that the proposed control algorithm improves vehicle motion in terms of yaw rate tracking, lateral movement, and minimization of deceleration.

Background This study investigated the association of 3 components of body composition (sarcopenia, intramuscular fat deposition and visceral adiposity) with the overall or recurrence-free survival of hepatocellular carcinoma (HCC) patients who underwent curative hepatic resection. Methods One hundred sixty newly diagnosed and surgically treated HCC patients were retrospectively enrolled from 2003 to 2011. Three items of body composition were measured using the 3rd lumbar level image of preoperative computed tomography (CT): psoas muscle index (PMI), psoas muscle attenuation (PMA), and visceral adipose tissue index (VATI). Sex-specific optimal cut-off for each item was determined from receiver-operating characteristic curves. Results The HCC patients showed a median age of 55 years, 75% of male, 78% of hepatitis B surface antigen positivity, and 96% of Child-Pugh A. The sarcopenic group (PMI less than the sex-specific cutoff of 3.33 cm2/m2 for men and 2.38 cm2/m2 for women) had 17.5% of the patients with a lower PMA (more fat deposition) but similar VATI compared to the non-sarcopenic group. PMI showed a positive correlation with PMA (ρ=0.493, P

Among the starting materials of thermoplastic polyurethanes (TPUs), it was confirmed that succinic acid-based polyester biopolyols having different molecular weights (Mn = 1000, 2000, and 4000) affect the physicochemical properties of the final polymer significantly. Bio-TPUs synthesized through a solvent-free one-shot polymerization process were synthesized with a polyester polyol, 1,4 butanediol (BDO), and 4,4′-methylene diphenyl diisocyanate (MDI) in a molar ratio of 1:1:2. As a control group, one typical petroleum-based TPU was synthesized and characterized along with other bio-based TPUs. Representative petroleum-based and bio-based TPUs synthesized were manufactured as monofilaments with a diameter of about 0.2 mm through an extrusion process with different draw ratios (4, 5, and 6 times). The molecular weight and structural properties of the TPUs were characterized by GPC and FT-IR analysis and thermal characterization by DSC and TGA analysis. Petroleum-based TPU and bio-based TPU having the same molecular weight soft segment (SS) tended to have similar molecular weight and hard segment (HS) content. TPUs with high HS content had excellent thermal stability, enabling stable extrusion of TPUs. In addition, it was confirmed that the bio-based TPU fibers produced in this way had a tensile strength corresponding to the physical properties of petroleum-based TPU fibers and an excellent elastic recovery rate of almost 100 %. These results indicate the application potential of bio-TPU.

This study aimed to investigate the feasibility of using artificial intelligence (AI) to identify normal chest radiography (CXR) from the worklist of radiologists in a health-screening environment.This retrospective simulation study was conducted using the CXRs of 5887 adults (mean age ± standard deviation, 55.4 ± 11.8 years; male, 4329) from three health screening centers in South Korea using a commercial AI (Lunit INSIGHT CXR3, version 3.5.8.8). Three board-certified thoracic radiologists reviewed CXR images for referable thoracic abnormalities and grouped the images into those with visible referable abnormalities (identified as abnormal by at least one reader) and those with clearly visible referable abnormalities (identified as abnormal by at least two readers). With AI-based simulated exclusion of normal CXR images, the percentages of normal images sorted and abnormal images erroneously removed were analyzed. Additionally, in a random subsample of 480 patients, the ability to identify visible referable abnormalities was compared among AI-unassisted reading (i.e., all images read by human readers without AI), AI-assisted reading (i.e., all images read by human readers with AI assistance as concurrent readers), and reading with AI triage (i.e., human reading of only those rendered abnormal by AI).Of 5887 CXR images, 405 (6.9%) and 227 (3.9%) contained visible and clearly visible abnormalities, respectively. With AI-based triage, 42.9% (2354/5482) of normal CXR images were removed at the cost of erroneous removal of 3.5% (14/405) and 1.8% (4/227) of CXR images with visible and clearly visible abnormalities, respectively. In the diagnostic performance study, AI triage removed 41.6% (188/452) of normal images from the worklist without missing visible abnormalities and increased the specificity for some readers without decreasing sensitivity.This study suggests the feasibility of sorting and removing normal CXRs using AI with a tailored cut-off to increase efficiency and reduce the workload of radiologists.

Background Replacement therapy is the most common treatment for reduction of bleeding and control of episodic bleeding in individuals with hemophilia. Despite the proven effectiveness of factor replacement therapy, repeated intravenous administration is a heavy burden to individuals with hemophilia. Objectives To reduce the burden, therapeutic agents that can be subcutaneously administered need to be developed, and an anti–tissue factor pathway inhibitor (TFPI) antibody may be a suitable candidate for this purpose. Methods MG1113 is an IgG4 monoclonal antibody that binds to Kunitz‐2 domain (KD2) of TFPI. To confirm the coagulation potential of MG1113, several tests were conducted using factor VIII (FVIII)‐ or IX (FIX)‐deficient plasma. For the ex vivo spiking test, platelet‐poor plasma samples from 14 individuals with hemophilia were spiked with MG1113. The in vivo efficacy was determined using blood loss tests, modified prothrombin time (mPT), and free TFPI quantification after intravenous or subcutaneous administration of MG1113 into hemophilia A (HA)‐induced rabbits. Results Radiographic crystallography demonstrated the specific binding site between MG1113 and KD2. In FVIII‐deficient plasma and the plasma of individuals with hemophilia, peak thrombin and endogenous thrombin levels were increased by MG1113 in a concentration‐dependent manner. Rotational thromboelastometry assay revealed that clotting time, clot formation time, and maximum clot firmness were normalized in MG1113‐treated blood of patients. Intravenous or subcutaneous injection of MG1113 into HA‐induced rabbits resulted in rebalancing of blood loss, mPT, and free TFPI levels. Conclusions These results indicate that subcutaneous administration of MG1113 neutralizes the function of TFPI and regulates bleeding in individuals with hemophilia.

Background/Aims: The role of serum myokine levels in sarcopenia and the outcome of hepatocellular carcinoma (HCC) patients are not clear. This study investigated the serum levels of myostatin, follistatin, and interleukin-6 (IL-6) in HCC patients and their association with sarcopenia and survival.Methods: Using prospectively collected pretreatment samples from 238 HCC patients in a hospital from 2012 to 2015, the serum levels of 3 myokines were determined and compared to 50 samples from age and sex-matched healthy controls. Sarcopenia was evaluated using the psoas muscle index (PMI) measured at the third lumbar level in the computed tomography, and clinical data were collected until 2017.Results: The median levels of the 3 myokines for the male and female HCC patients were as follow: myostatin (3,979.3 and 2,976.3 pg/mL), follistatin (2,118.5 and 2,174.6 pg/mL), and IL-6 (2.5 and 2.7 pg/mL), respectively. Those in the HCC patients were all significantly higher than in the healthy controls. In the HCC patient, the median PMI was 4.43 (males) and 2.17 cm2/m2 (females) with a sarcopenic prevalence of 56.4%. The serum levels of myostatin, IL-6 and follistatin in the HCC patients showed a positive, negative, and no correlation with PMI, respectively. The serum follistatin level was an independent factor for poor survival in HCC patients.Conclusions: The serum levels of myostatin, follistatin, and IL-6 and their correlation with sarcopenia and survival were presented in HCC patients for the first time. The role of the serum follistatin level as a poor prognostic biomarker warrants further study.

To compare the coronary vasodilation effects of spray with those induced by tablet administration in coronary CT angiography (CCTA). A total of 2024 patients who underwent CCTA were identified for this retrospective study, including 828 patients with spray (spray group) and 1169 with tablets (tablet group). Of these, 93 patients underwent CCTA at least twice using both spray and tablets. The number of measurable segments and diameters of all 18 segments was measured. The number of measurable segments was compared between groups. No statistically significant differences were evident between these two groups in terms of clinical characteristics. All coronary segments except the ramus intermedius (RI) and left posterior descending artery (L-PDA) were significantly larger in the spray group than in the tablet group (all p

A colorimetric hydrogen sensor has great potential for accurately detecting and monitoring the leakage of hydrogen gas on account of its fast color change in contact with hydrogen gas. However, for the practical application of the sensor, such as in gas detection systems in clothing, the flexibility and stability of the sensor need to be improved. Here, we present a novel method to fabricate a flexible colorimetric hydrogen sensor with the stable embedment of sensing material. To improve the flexibility and stability of the sensor, polyacrylonitrile nanofiber containing palladium oxide and zinc oxide hybrid nanoparticles was prepared by electrospinning. The flexible colorimetric hydrogen sensor can detect 1000 ppm hydrogen gas with excellent selectivity within 2 min. We also suggest film and yarn-type flexible colorimetric hydrogen sensors for industrial and wearable applications. A laminating process was used to prepare the film. In contrast, twisting and polydimethylsiloxane coating were used to prepare the yarn-type flexible colorimetric hydrogen sensor. Compared with a flexible colorimetric hydrogen-sensing nanofiber, the film and yarn show identical sensitivity for detecting a hydrogen leakage. These applications of hydrogen sensors could be a new insight into the design of a flexible sensor for detecting hydrogen leakage with the naked eye.

Background/Aims We performed a large-scale, retrospective, nationwide, cohort study to investigate the risk factors for lung cancer among never-smoking Korean females. Methods The study data were collected from a general health examination and questionnaire survey of eligible populations conducted between January 1, 2003 and December 31, 2004; the data were acquired from the tailored big data distribution service of the National Health Insurance Service. After a 1-year clearance period, 5,860,922 of 6,318,878 never-smoking female participants with no previous history of lung cancer were investigated. After a median follow-up of 11.4 years, 43,473 (0.74%) participants were defined as “newly diagnosed lung cancer”. Results After adjusting for all variables at baseline, the variables older age, lower body mass index (BMI), less exercise, frequent alcohol drinking, meat-based diet, rural residence, and previous history of cancer were associated with a higher incidence of lung cancer. Low BMI (< 18.5 kg/m2: hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.27 to 1.40) was a significant independent risk factor; as BMI decreased, HR increased. Negative associations between BMI and lung-cancer development were also observed after controlling for age (p for trend < 0.001). Drinking alcohol one to two times a week (HR, 1.25; 95% CI, 1.21 to 1.28) and eating a meat-based diet (HR, 1.08; 95% CI, 1.01 to 1.15) were associated with lung-cancer incidence. Conclusions Modifiable baseline characteristics, such as BMI, exercise, alcohol consumption, and diet, are risk factors for lung-cancer development among never- smoking females. Thus, lifestyle modifications may help prevent lung cancer.

As interest in autonomous driving increases, technology development for autonomous vehicles is rapidly progressing. However, the ability of a general driver in using real autonomous driving technology to cope with the development of autonomous driving technology is different from the development of real technology. Therefore, this paper presents a driver’s experience in autonomous driving by experimenting with a Human-In-The-Loop(HITL) simulator and an actual vehicle. At the same time, the UTAUT model, which is an existing Technology Acceptance Analysis Model, is customized with the characteristics of autonomous vehicles to analyze the acceptance level of drivers in general. As a result, this paper proposes the modified UTAUT model that is considered reliable and valid for autonomous vehicles. Second, the result of the analyzed correlation between independent and dependent variables is presented by the modified UTAUT model. Finally, the relation between technology acceptance for autonomous vehicles and participant characteristics is presented.

To propose fully automatic segmentation of left atrium using active learning with limited dataset in late gadolinium enhancement in cardiac magnetic resonance imaging (LGE-CMRI).An active learning framework was developed to segment the left atrium in cardiac LGE-CMRI. Patients (n = 98) with atrial fibrillation from the Korea University Anam Hospital were enrolled. First, 20 cases were delineated for ground truths by two experts and used for training a draft model. Second, the 20 cases from the first step and 50 new cases, corrected in a human-in-the-loop manner after predicting using the draft model, were used to train the next model; all 98 cases (70 cases from the second step and 28 new cases) were trained. An additional 20 LGE-CMRI were evaluated in each step.The Dice coefficients for the three steps were 0.85 ± 0.06, 0.89 ± 0.02, and 0.90 ± 0.02, respectively. The biases (95% confidence interval) in the Bland-Altman plots of each step were 6.36% (-14.90-27.61), 6.21% (-9.62-22.03), and 2.68% (-8.57-13.93). Deep active learning-based annotation times were 218 ± 31 seconds, 36.70 ± 18 seconds, and 36.56 ± 15 seconds, respectively.Deep active learning reduced annotation time and enabled efficient training on limited LGE-CMRI.

In this study, the morphological effects of ZnO on the antimicrobial and deodorant activities of synthetic fibers were investigated. Three different polyethylene terephthalate (PET)/ZnO filaments were prepared by incorporating various ZnO nanostructures (rods, plates, and spheres) into PET filaments via a melt-spinning process. The antimicrobial activity of the as-prepared fibers was evaluated by the shake-flask method using two types of bacteria (Staphylococcus aureus and Klebsiella pneumoniae). The deodorant activity of the as-prepared fibers was evaluated by the gas detection tube method. All the PET/ZnO filaments exhibited excellent antimicrobial activity with a bacterial reduction value of 99.9%. The PET/ZnO rod filament showed the best deodorant performance of 60.0%. Both the antimicrobial and deodorant activities of the PET/ZnO filaments were influenced by the morphology of ZnO. However, the morphology of ZnO had a different effect on each functionality of the PET/ZnO filaments. The antimicrobial activity of the PET/ZnO filaments was mainly affected by the physical properties of ZnO rather than its morphology. By contrast, the deodorant activity of the PET/ZnO filaments was highly influenced by the morphology of ZnO.

It is essential for autonomous vehicles at level 3 or higher to have the ability to predict the trajectories of surrounding vehicles to safely and effectively plan and drive along trajectories in complex traffic situations. However, predicting the future behavior of vehicles is a challenging issue because traffic vehicles each have different drivers with different driving tendencies and intentions and they interact with each other. This paper presents a Long Short-Term Memory (LSTM) encoder–decoder model that utilizes an attention mechanism that focuses on certain information to predict vehicles’ trajectories. The proposed model was trained using the Highway Drone (HighD) dataset, which is a high-precision, large-scale traffic dataset. We also compared this model to previous studies. Our model effectively predicted future trajectories by using an attention mechanism to manage the importance of the driving flow of the target and adjacent vehicles and the target vehicle’s dynamics in each driving situation. Furthermore, this study presents a method of linearizing the road geometry such that the trajectory prediction model can be used in a variety of road environments. We verified that the road geometry linearization mechanism can improve the trajectory prediction model’s performance on various road environments in a virtual test-driving simulator constructed based on actual road data.

In this study, side-by-side bicomponent fibers were prepared by melt spinning using bio-based thermoplastic polyurethane (TPU) and TPU/polylactic acid (PLA) blends. The morphology, thermal and mechanical properties of the fibers were investigated. To this end, the synthesis of TPU using biomass-based polyols and the preparation of TPU/PLA blends were preceded. Their morphological and structural characteristics were investigated. The synthesis of TPU was confirmed through Fourier transform infrared analysis, and as a result of gel permeation chromatograph analysis, a compound having a weight average molecular weight of 196,107 was synthesized. The TPU/PLA blends were blended in the ratio of 80/20, 60/40, 40/60, and 20/80 through a melt extruder. They formed a sea–island structure as a result of scanning electron microscope analysis, and an increase in the PLA content in the TPU matrix caused a decrease in the melt flow index. Finally, TPU/(TPU/PLA) side-by-side bicomponent fibers were prepared by utilizing the above two materials. These fibers exhibited tensile strengths of up to 3624 MPa, with improved biocarbon content of up to 71.5%. These results demonstrate the potential of TPU/(TPU/PLA) side-by-side bicomponent fibers for various applications.

The aim of this study was to evaluate the CT and PET-CT features of solitary pulmonary capillary hemangioma (SPCH) with clinicopathologic correlations. This retrospective study included 17 patients with histologically proven SPCH from four tertiary institutions. The clinical, pathological and imaging findings of SPCH were reviewed. The CT features assessed included lesion location, size, density, contour, margin, enhancement, presence of air bronchogram, perivascular lucency and pleural retraction, and 18F-fluorodeoxyglucose uptake on PET-CT. Changes in the size during the follow-up period were also evaluated. Imaging features were correlated with the clinicopathologic findings. The mean age of the patients was 47 years (range 30–60 years). All SPCHs were incidentally detected during screening CT examinations (n = 13, 76%) or during cancer work-up (n = 4, 24%). Most SPCHs appeared as part-solid nodules (n = 15, 88%), the remaining appeared as a pure ground-glass nodule or a pure solid nodule, respectively. Most had smooth contours (n = 16, 94%), while one had a lobulated contour. Nine SPCHs (53%) showed ill-defined margins. Air bronchogram was present in ten (59%) SPCHs, and perivascular lucency in two (12%). All SPCHs exhibited hypoattenuation on contrast-enhanced CT and hypometabolism on PET-CT. During the follow-up period (mean 14.8 ± 17.7 months), the lesions showed no change in size or density in ten SPCHs (59%), decreased or fluctuation in size and density in three (18%). SPCH is often incidentally detected in young and middle-aged adults, commonly as an ill-defined part-solid nodule that may accompany air bronchogram, perivascular lucency, and fluctuation in size or density on CT and hypometabolism on PET-CT.

This study aimed to evaluate the exposure levels and variation in airborne endotoxin and heavy metals such as aluminum, chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), zinc, and lead (Pb) in the three different South Korean subway environments (driver room, station office, and underground tunnel) and identify subway characteristics influencing endotoxin and heavy metals levels. Air samples were collected and analyzed using the kinetic Limulus Amebocyte Lysate assay and inductively coupled plasma mass spectrometers. The geometric mean was determined for endotoxin levels (0.693 EU/m3). It was also found that Fe (5.070 µg/m3) had the highest levels in subway environments while Pb (0.008 µg/m3) had the lowest levels. Endotoxin levels were higher in the underground tunnel and lower in the station office; the total heavy metal levels showed the same pattern with endotoxin levels. Endotoxins and total heavy metal levels were higher in the morning than at night. Positive correlations were found between endotoxin and Cr, Fe, Mn, and Ni levels. Given the correlation between airborne endotoxins and heavy metals, further studies with larger sample sizes are needed to identify the correlation between levels of airborne endotoxin and heavy metals.

To develop Korean coronavirus disease (COVID-19) chest imaging justification guidelines, eight key questions were selected and the following recommendations were made with the evidence-based clinical imaging guideline adaptation methodology. It is appropriate not to use chest imaging tests (chest radiograph or CT) for the diagnosis of COVID-19 in asymptomatic patients. If reverse transcription-polymerase chain reaction testing is not available or if results are delayed or are initially negative in the presence of symptoms suggestive of COVID-19, chest imaging tests may be considered. In addition to clinical evaluations and laboratory tests, chest imaging may be contemplated to determine hospital admission for asymptomatic or mildly symptomatic unhospitalized patients with confirmed COVID-19. In hospitalized patients with confirmed COVID-19, chest imaging may be advised to determine or modify treatment alternatives. CT angiography may be considered if hemoptysis or pulmonary embolism is clinically suspected in a patient with confirmed COVID-19. For COVID-19 patients with improved symptoms, chest imaging is not recommended to make decisions regarding hospital discharge. For patients with functional impairment after recovery from COVID-19, chest imaging may be considered to distinguish a potentially treatable disease.

In this study, highly porous carbon fiber was prepared for hydrogen storage. Porous carbon fiber (PCF) and activated porous carbon fiber (APCF) were derived by carbonization and chemical activation after selectively removing polyvinyl alcohol from a bi-component fiber composed of polyvinyl alcohol and polyacrylonitrile (PAN). The chemical activation created more pores on the surface of the PCF, and consequently, highly porous APCF was obtained with an improved BET surface area (3058 m2 g−1) and micropore volume (1.18 cm3 g−1) compare to those of the carbon fiber, which was prepared by calcination of monocomponent PAN. APCF was revealed to be very efficient for hydrogen storage, its hydrogen capacity of 5.14 wt% at 77 K and 10 MPa. Such hydrogen storage capacity is much higher than that of activated carbon fibers reported previously. To further enhance hydrogen storage capacity, catalytic Pd nanoparticles were deposited on the surface of the APCF. The Pd-deposited APCF exhibits a high hydrogen storage capacity of 5.45 wt% at 77 K and 10 MPa. The results demonstrate the potential of Pd-deposited APCF for efficient hydrogen storage.

This study evaluates indoor air concentrations of CO2, NO2, and O3 and their relationship to other indoor environmental factors in facilities with occupants susceptible to air contaminants, such as hospitals, senior specialized hospitals, elderly care facilities, and postnatal care centers. Indoor air samples were collected from 82 indoor facilities in South Korea and organized by region. Spearman’s correlation and Kruskal–Wallis analyses were employed to examine the relationship among and differences between contaminants in the indoor facilities and indoor/outdoor differences of NO2 and O3 concentrations. Significant correlations were found between CO2 and NO2 concentrations (r2 = 0.176, p

Background Electrophysiology studies have demonstrated that left atrial late gadolinium enhancement (LGE) is associated with the chronicity of atrial fibrillation (AF). To date, cardiac MRI has been used to assess the extent of atrial LGE but not the distribution pattern of LGE in the left atrium. Purpose To determine whether the MRI pattern of left atrial fibrosis is associated with the chronicity of AF. Materials and Methods This retrospective study included patients with AF who underwent LGE MRI between June 2017 and May 2018. The presence of left atrial LGE was assessed at nine left atrial segments; the extent was determined by the number of segments involved. According to the chronicity of AF, patients were separated into paroxysmal AF (PAF) and persistent AF (PeAF) groups. The location and extent of left atrial LGE were compared between PAF and PeAF by using the χ2 test and logistic regression analysis. Results Of the 195 patients (mean age, 55 years ± 10 [standard deviation], 161 men), 74 (38%) had PAF and 121 (62%) had PeAF. Of all patients, 114 (58.4%) had at least one left atrial LGE segment. The mean number of LGE segments was higher (1.4 ± 1.1 vs 0.6 ± 0.7, P = .002) in the PeAF group than in the PAF group. The incidence of LGE at the left inferior pulmonary vein (LIPV) antrum was higher in the PeAF group than in the PAF group (39.2% [29 of 74] vs 7.4% [nine of 121]; P < .001). In multivariable analysis, LGE at the LIPV antrum was independently associated with PeAF (odds ratio = 4.2; 95% confidence interval: 1.7, 10.5; P < .001). Conclusion The presence of fibrosis assessed with late gadolinium enhancement MRI of the left inferior pulmonary vein antrum was associated with persistent atrial fibrillation. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Almeida in this issue.

To evaluate the size of a postoperative lymphocele in the coronal and axial reconstruction planes using multidetector computed tomography (MDCT) in kidney transplantation recipients.We evaluated 92 recipients who underwent MDCT of the abdominopelvis at 1 month after kidney transplantation. The axial short axis, axial surface area, coronal short axis, and coronal surface area of the lymphocele were measured using the reconstructed MDCT coronal and axial images. Depending on the clinical manifestations and radiologic findings of the recipients, all lymphoceles were classified into symptomatic and asymptomatic. We compared the suitability of the size measurement on coronal and axial planes of MDCT reconstruction for symptomatic lymphocele in kidney transplant recipients using Spearman's correlation analysis and comparisons of receiver operating characteristic (ROC) curves.Areas under the ROC curves were 0.957 and 0.928 for the axial short axis and axial surface area and 0.968 and 0.966 for the coronal short axis and coronal surface area, respectively. In pairwise comparison of the ROC curve of the parameters of the symptomatic lymphoceles, the coronal measurement was significant in contrast to the axial measurement (short axis, P=0.357; surface area, P=0.047).For the prediction of symptomatic lymphoceles using MDCT, the coronal measurement of postoperative lymphoceles can significantly improve diagnostic performance over axial measurement in kidney transplant recipients.

This paper evaluates the NVH characteristics of an air compressor for fuel cell electric vehicles(FCEVs) by conducting experimental as well as on-road tests. For the experiment, five eddy-current-type displacement sensors measured the vibration amplitudes of the shaft at the impeller and thrust runner ends, one three-axis accelerometer measured the acceleration of the compressor housing, and one microphone placed 1 m away from the test air compressor measured the acoustic pressure during rotor speed-up and coastdown up to 100 k r/min. For the on-road test, the air compressor was installed under the stack frame of a proto-type FCEV. The stack frame supports a fuel cell stack and is fixed on the sub-frame of the FCEV. In addition to five eddy-current-type displacement sensors and one three-axis accelerometer installed in the air compressor housing, two three-axis accelerometers installed on the stack frame and the sub-frame measured their accelerations during FCEV speed-up and break-down up to 115 km/h. One microphone installed 30 cm behind the air compressor recorded the acoustic pressure. All measured displacements, accelerations, and acoustic pressures were analyzed in the frequency domain. The test results revealed that the air compressor has the highest rotor vibrational amplitude and housing acceleration at the maximum rotor speed of 100 k r/min. However, the vibrations of the air compressor are well dampened while transmitteed to the sub-frame of the FCEV.

To reduce the calculation time needed to determine the optimal path, the form of the road and the path of an autonomous vehicle were linearized; additionally, among multiple obstacles, only those that were potentially dangerous were chosen. By considering the movement of moving obstacles, the cost was calculated. The calculation time was shortened by reducing the number of design variables of the optimal path, when changing lanes to avoid obstacles, to two. Limiting conditions, such as the lateral and longitudinal acceleration, were excluded from the cost calculation by restricting the search region of the design variable. The final result was calculated using a relatively free search of the golden-section search regarding the initial value setting. For the golden-section search, the number of final design variables was reduced to one; this was done by optimizing the search direction. The search direction was determined based on the final position of the vehicles and the calculated optimal points. By including a collision avoidance algorithm and moving in a short period of time, the calculated optimal path prevented accidents due to path errors caused by simplification. The path could be found easily, even for complex road shapes and with multiple vehicles nearby.

Atrial fibrillation (AF) is the most common arrhythmia associated with the risk of morbidity and mortality in clinical patients. AF is considered as an arrhythmia type that develops and progresses through close connection with cardiac structural arrhythmogenic substrates. Since the introduction of catheter ablation-mediated electrical isolation of arrhythmogenic substrates, cardiac imaging indicates improved treatment outcome and prognosis with appropriate candidate selection, ablation catheter guidance, and post-ablation follow-up. Currently, cardiac computed tomography (CCT) and cardiovascular magnetic resonance (CMR) imaging are essential in the case management of AF at both pre-and post-procedural stages of catheter ablation. In this review, we discuss the roles and technical considerations of CCT and CMR imaging in the management of patients with AF undergoing catheter ablation.

We measured the concentrations of indoor pollutants (fine particulate matter (PM10)), culturable airborne bacteria (CAB), total volatile organic compounds (TVOCs), formaldehyde (HCHO), CO2, NO2, and O3 in subway stations and public parking lots at a national scale in South Korea in order to determine their possible relationships with other underground environmental factors and facility characteristics. Indoor pollutants were sampled at 59 underground facilities with a total of 187 samples in subway stations and parking lots. Kruskal–Wallis and Mann–Whitney analyses were used to examine the relationships between atmospheric pollutants at underground facilities and indoor/outdoor differences in PM10 and O3 concentrations. Underground PM10 concentrations were higher than outdoor concentrations at all underground facilities (p

We measured the levels of airborne endotoxins in South Korea and compared them to PM10, PM2.5, and O3 levels in ambient environments; environmental factors affecting these levels were also analyzed. A total of 81 air samples were collected and analyzed using the kinetic Limulus Amebocyte Lysate (LAL) assay. The geometric mean was determined for the levels of endotoxin (0.132 EU m–3), PM10 (51.9 µg m–3), PM2.5 (22.6 µg m–3), and O3 (0.018 ppm). The endotoxin levels were significantly higher in fall and winter than in summer. The levels of PM10 and PM2.5 were significantly higher, and the level of O3 was by far its highest, in spring. Negative correlations were found between the endotoxin and O3 levels (r = –0.491) and between the endotoxin levels and temperature (r = –0.302). The PM10 levels were also negatively associated with the O3 levels and temperature but positively associated with the PM2.5 levels. Given the negative relationship between airborne endotoxins and O3 determined here, further studies with larger sample sizes are needed to identify the responsible mechanisms.

The purpose of this chapter is to develop a virtual simulation environment useful for electric vehicle performance analysis. For user convenience, it is possible to change the electric vehicle's key components or modify their parameters using MATLAB/Simulink. In addition, the developed simulation model can be simulated in real-time, and it is mounted on the driving simulator so that the designer can observe the change in performance due to modification in components or specifications. Using a driving simulator, the actual driver drives in different traffic conditions, resulting in various simulation results. Therefore, designers can change the specifications of the components used or the components themselves to find the impact on the electric vehicle's performance. This process will shorten the development time of electric vehicles by selecting components suitable for electric vehicles' required performance.

This study aimed to evaluate the effect of implementing the consensus statement from the Asian Society of Cardiovascular Imaging-Practical Tutorial 2020 (ASCI-PT 2020) on the reliability of cardiac MR with late gadolinium enhancement (CMR-LGE) myocardial viability scoring between observers in the context of ischemic cardiomyopathy.A total of 17 cardiovascular imaging experts from five different countries evaluated CMR obtained in 26 patients (male:female, 23:3; median age [interquartile range], 55.5 years [50-61.8]) with ischemic cardiomyopathy. For LGE scoring, based on the 17 segments, the extent of LGE in each segment was graded using a five-point scoring system ranging from 0 to 4 before and after exposure according to the consensus statement. All scoring was performed via web-based review. Scores for slices, vascular territories, and total scores were obtained as the sum of the relevant segmental scores. Interobserver reliability for segment scores was assessed using Fleiss' kappa, while the intraclass correlation coefficient (ICC) was used for slice score, vascular territory score, and total score. Inter-observer agreement was assessed using the limits of agreement from the mean (LoA).Interobserver reliability (Fleiss' kappa) in each segment ranged 0.242-0.662 before the consensus and increased to 0.301-0.774 after the consensus. The interobserver reliability (ICC) for each slice, each vascular territory, and total score increased after the consensus (slice, 0.728-0.805 and 0.849-0.884; vascular territory, 0.756-0.902 and 0.852-0.941; total score, 0.847 and 0.913, before and after implementing the consensus statement, respectively. Interobserver agreement in scoring also improved with the implementation of the consensus for all slices, vascular territories, and total score. The LoA for the total score narrowed from ± 10.36 points to ± 7.12 points.The interobserver reliability and agreement for CMR-LGE scoring for ischemic cardiomyopathy improved when following guidance from the ASCI-PT 2020 consensus statement.

Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) characterized by an inhaled inciting antigen that leads to the inflammation of the lung parenchyma and small airway with immunologic reactions. Over the last decades, the most effective therapeutic option for HP has been limited to antigen avoidance. The differential diagnosis of HP from other ILDs is the beginning of treatment as well as diagnosis. However, the presence of several overlapping clinical and radiologic features makes differentiating HP from other ILDs particularly challenging. In 2020, a multidisciplinary committee of experts from the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax suggested a new clinical practice guideline classifying HP into nonfibrotic and fibrotic phenotypes on the basis of chest high-resolution CT (HRCT) findings. Therefore, we introduced a new diagnostic algorithm based on chest HRCT in the clinical practice guideline for the diagnosis of HP.

To explore the importance of quantitative characteristics of dual-energy CT (DECT) between pulmonary metastasis and benign lung nodules in thyroid cancer. In this retrospective study, we identified 63 patients from our institution’s database with pathologically proven thyroid cancer who underwent DECT to assess pulmonary metastasis. Among these patients, 22 had 55 pulmonary metastases, and 41 had 97 benign nodules. If nodules showed increased iodine uptake on I-131 single-photon emission computed tomography-computed tomography or increased size in follow-up CT, they were considered metastatic. We compared the clinical findings and DECT parameters of both groups and performed a receiver operating characteristic analysis to evaluate the optimal cutoff values of the DECT parameters. Patients with metastases were significantly older than patients with benign nodules (p = 0.048). The DECT parameters of the metastatic nodules were significantly higher than those of the benign nodules (iodine concentration [IC], 5.61 ± 2.02 mg/mL vs. 1.61 ± 0.98 mg/mL; normalized IC [NIC], 0.60 ± 0.20 vs. 0.16 ± 0.11; NIC using pulmonary artery [NICPA], 0.60 ± 0.44 vs. 0.15 ± 0.11; slope of the spectral attenuation curves [λHU], 5.18 ± 2.54 vs. 2.12 ± 1.39; and Z-effective value [Zeff], 10.0 ± 0.94 vs. 8.79 ± 0.75; all p < 0.001). In the subgroup analysis according to nodule size, all DECT parameters of the metastatic nodules in all subgroups were significantly higher than those of the benign nodules (all p < 0.05). The cutoff values for IC, NIC, λHU, NICPA, and Zeff for diagnosing metastases were 3.10, 0.29, 3.57, 0.28, and 9.34, respectively (all p < 0.001). DECT parameters can help to differentiate metastatic and benign lung nodules in thyroid cancer. • DECT parameters can help to differentiate metastatic and benign lung nodules in patients with thyroid cancer. • DECT parameters showed a significant difference between benign lung nodules and lung metastases, even for nodules with diameters ≥ 3 mm and