Search

This paper presents a large-scale base station antenna assembly structure that is low-cost, reliable, and easy to manufacture. The antenna element is composed of a low-loss liquid crystal polymer based on a plastic molded module and a modified wideband stacked patch antenna. The base station antenna consists of a 4 × 8 antenna module, with each module comprising 3 × 1 subarrays along with dual-polarized antenna elements. The antenna element achieved an efficiency of 91% and an impedance bandwidth of 1.14 GHz within a height of 10 mm at 3.7 GHz. Furthermore, the fabricated array antenna structure was tested and verified to have an effective isotropic radiated power of 75.6 dBm at boresight and a steering range of less than ±60°. Therefore, the proposed structure meets the required antenna and beam-forming performance for commercial 5G active antenna systems.

Abstract Objectives We primarily aimed to evaluate whether parotid incidental lesion (PIL) in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for staging evaluation of patients with hepatocellular carcinoma (HCC) would represent a possibility of extrahepatic metastasis or second primary malignancy (SPM). Additionally, we explored the incidence of PIL in HCC patients and examined any associated risk factors. Methods We retrospectively analyzed patients with HCC who underwent 18F-FDG PET/CT at our institution from 2010 to 2022. The pathological findings of PILs in HCC patients were investigated for confirmatory identification of the risk of HCC metastasis or SPM in parotid gland. Healthy controls received 18F-FDG PET/CT for health screening were also enrolled to compare the incidence of PILs with HCC patients. Various parameters associated with patient demographics and characteristics of HCC were analyzed to find the related factors of PILs. Results A total of 17,674 patients with HCC and 2,090 healthy individuals who had undergone 18F-FDG PET/CT scans were enrolled in the analyses. Among the 54 HCC patients who underwent pathological confirmation for PILs, benign primary parotid tumor was most commonly observed (n = 43 [79.6%]); however, no malignant lesions were detected, including HCC metastasis. The incidence of PILs was higher in patients diagnosed with HCC compared with the control group (485 [2.7%] vs. 23 [1.1%], p = 0.002). Analysis for the risk factors for PILs revealed that patient age, sex, and positive viral markers were significantly associated with the incidence of PILs in patients with HCC (all p

As drone intrusions into important facilities have increased, research on drone countermeasures has been conducted to counter drones. In this study, we developed a reinforcement learning (RL)-based counter fixed-wing drone system that can respond to fixed-wing drones in autonomous flight with soft kills. The system redirects fixed-wing drones to a designated target position using the global navigation satellite system (GNSS) deception based on the drone’s position and speed measured by RADAR. In this study, to construct an environment for training an RL agent, simplified drone modeling was performed for two types of fixed wing drones, and the RADAR error measured through flight tests was modeled. Subsequently, the Markov decision process (MDP) was defined to enable redirection without prior information regarding fixed-wing drones. After applying the RL agent trained in the defined MDP and environment to the counter fixed-wing drone system, the simulation and flight test results confirmed that redirection was possible for both types of fixed-wing drones.

Background The most common type of carcinoma ex pleomorphic adenoma (CPA) is histologically equivalent to salivary duct carcinoma, which has an apocrine phenotype. Invasive CPA is often accompanied by non-invasive or in situ carcinoma, an observation that suggests the presence of precursor lesions. The aim of this study was to identify candidate precursor lesions of CPA within pleomorphic adenoma (PA). Methods Eleven resected cases of CPA with residual PA and 17 cases of PA with atypical changes were subjected to immunohistochemistry (IHC) for p53, human epidermal growth factor receptor 2 (HER2), androgen receptor (AR), pleomorphic adenoma gene 1, gross cystic disease fluid protein-15 (GCDFP-15), and anti-mitochondrial antibody. Results Invasive or in situ carcinoma cells in all CPAs were positive for AR, GCDFP-15, and HER2. Atypical foci in PAs corresponded to either apocrine or oncocytic changes on the basis of their reactivity to AR, GCDFP-15, and anti-mitochondrial antibody. Atypical cells in PAs surrounding CPAs had an apocrine phenotype without HER2 expression. Conclusions Our study identified frequent apocrine changes in residual PAs in CPA cases, suggesting a possible precursor role of apocrine changes. We recommend the use of HER2 IHC in atypical PAs, and that clinicians take HER2 positivity into serious consideration.

Abstract Regular safety inspections of existing reinforced concrete (RC) structures are required according to the regulations and criteria set by each country. In South Korea, the safety inspection regulations provided by the Korea Infrastructure Safety and Technology Corporation (KISTEC) are followed. These regulations were developed based on fuzzy theory to avoid subjective decisions, and provide standardized deterioration grades for member types, floors, and the entire structure. However, the safety inspection regulation by the KISTEC often provides unconservative evaluation results. In particular, as the importance factors of beam and slab members are set lower than those of other members, there are cases in which deteriorations occurring in beams and slabs are not properly reflected in the floor level evaluation. In this study, to overcome such limitations, case studies were carried out and modified importance factors for structural member types were proposed considering the failure probabilities of each member type based on the reliability theory. The importance modification factor was calculated based on the strength ratio of structural members so that the more dangerous the members are, the more impact they give on the evaluation. Overall, compared to the KISTEC method, the proposed method provided conservative but practical assessment results, and it was found that the proposed importance factors can be very useful to properly reflect the effects of damaged members on the deterioration status evaluation of the floors and the entire structure.

Abstract Vocal cord paralysis caused by recurrent laryngeal nerve (RLN) injury during thyroidectomy results in hoarseness, aspiration, and dyspnea. We evaluated the usefulness of nerve guidance conduits (NGCs) constructed from an asymmetric polycaprolactone (PCL)/Pluronic F127 porous membrane and filled with platelet-rich plasma (PRP) for functional RLN regeneration. We evaluated the proliferation and migration of Schwann cells (SCs) after PRP treatment in vitro. For the in vivo study, rabbits were divided into a non-loaded NGC group and a PRP-loaded NGC group. The left RLNs were resected and interposed with the NGCs. Functional and histological examinations of the vocal cords were performed. SC proliferation and migration increased in a PRP dose-dependent manner, with the PRP increasing the levels of neurotrophic factors, myelin-associated glycoprotein, and ERK. In vivo, the PRP group showed significantly better vocal cord mobility and less vocalis muscle atrophy than the non-loaded NGC group. Histologically, the ingrowth of nerve endings occurred more rapidly in the PRP group, and acetylcholinesterase, neurofilament, and S-100 expression in neural endings were significantly higher in the PRP group. Furthermore, transmission electron microscopy showed that myelinated axons were more tightly packed in the PRP group. This study shows that PRP-loaded NGCs provide a favorable environment for neural regeneration and suggests that this technique has therapeutic potential for promoting RLN recovery.

Abstract Bond–slip is an important characteristic that determines the stiffness, displacement, and load-bearing capacity of a reinforced concrete (RC) beam. It is essential for performing a precise numerical analysis of the beam. In most cases, bond–slip models can define the bond–slip curve only when there are experimental data. However, many bond test data have been obtained from pull-out tests, and the dominant view is that the bond–slip behavior observed in the pull-out test is quite different from that in an actual RC beam. Therefore, a mapping function that makes it possible to estimate the bond–slip behaviors of beam specimens using those of pull-out specimens was developed in this study. A total of 255 pull-out specimen data and 75 beam specimen data were collected from previous studies, and the importance and influence of each feature of the two groups were analyzed using random forest and K-means clustering. The mapping function was derived using genetic programming, and its accuracy was verified through a comparison with existing models. The proposed model exhibits a high degree of accuracy in estimating bond–slip and bond strength in beam specimens and can provide useful information for understanding the difference in bond–slip behaviors between the two groups.

Silk fiber, recognized as a versatile bioresource, holds wide-ranging significance in agriculture and the textile industry. During the breeding of silkworms to yield new varieties, optical sensing techniques have been employed to distinguish the colors of silk cocoons, aiming to assess their improved suitability across diverse industries. Despite visual comparison retaining its primary role in differentiating colors among a range of silk fibers, the presence of uneven surface texture leads to color distortion and inconsistent color perception at varying viewing angles. As a result, these distorted and inconsistent visual assessments contribute to unnecessary fiber wastage within the textile industry. To solve these issues, we have devised an optical system employing an integrating sphere to deliver consistent and uniform illumination from all orientations. Utilizing a ColorChecker, we calibrated the RGB values of silk cocoon images taken within the integrating sphere setup. This process accurately extracts the authentic RGB values of the silk cocoons. Our study not only helps in unraveling the intricate color of silk cocoons but also presents a unique approach applicable to various specimens with uneven surface textures.

ObjectiveHypopharyngeal cancer is managed by either surgical resection or radiation therapy-based treatment. In choosing the treatment modality, the patient’s swallowing function should be considered to achieve optimal treatment outcomes. This study aimed to stratify the risk factors predictive of postoperative dysphagia in hypopharyngeal cancer.Study DesignRetrospective study.SettingTertiary referral center.MethodsWe enrolled 100 patients who were diagnosed with hypopharyngeal cancer and underwent curative surgery between January 2010 and December 2019, and retrospectively reviewed their medical records.ResultsPostoperative dysphagia occurred in 29 patients (29%) who required a tracheostomy tube or percutaneous gastrostomy tube for feeding or preventing aspiration; additionally, the overall survival rate was lower in those patients than in those without dysphagia. The univariate analysis revealed that postoperative dysphagia was associated with clinical T stage (p = 0.016), N stage (p = 0.002), and surgical resection extent of the larynx and pharynx (p

ObjectivePostoperative delirium is known to have various adverse effects on head and neck surgery patients. This study was designed to identify possible risk factors of delirium following long periods of head and neck cancer surgery and to help prevent postoperative delirium.MethodsWe enrolled 197 patients who underwent long-time (>6 h) head and neck surgery at the Asan Medical Center from January 2017 to December 2018 in this study. Clinical covariates that may be associated with delirium were analyzed retrospectively using univariate and multivariate analyses.ResultsDelirium occurred in 18 patients (9.1%). Within the first 7 days, 16 patients (88.9%) experienced delirium. Upon univariate analysis, delirium was associated with old age (≥75, p = 0.001), past neurological history (p = 0.019), time to ambulation (p = 0.014), and postoperative hospital day (p = 0.048). In multivariate analysis, old age (≥75, odds ratios (OR) 6.16, CI 2.00–19.00, p = 0.002), time to ambulation (OR 1.04, CI 1.01–1.07, p = 0.017), and past neurological history (OR 5.26, CI 1.09–25.37, p = 0.039) were significant risk factors associated with postoperative delirium.ConclusionsOlder patients or patients with neurologic history must be attended with care, especially early after surgery. Encouraging early ambulation might lower the incidence of postoperative delirium and, subsequently, reduce adverse effects. This result could benefit patients by helping them avoid undesirable outcomes.

Gobioidei is one of the largest vertebrate taxa with over 2000 species observed around the globe. The largest group in Gobioidei is gobies that had been classified as one family, Gobiidae, based on morphological features. Molecular phylogenetic studies revealed that gobies consisted of two monophyletic families, Gobiidae and Oxudercidae, in which 19 lineages have been proposed, despite some claims arisen about the relationship among these lineages or species. We analyzed 58 Gobioidei species, including 45 East Asian oxudercids, based on 12S rRNA sequences to reconstruct the spatiotemporal diversification history of gobies. Our analysis yielded the results compatible with the previous reports in a large framework. The common ancestor of Gobiidae and Oxudercidae were estimated to appear at 38.66 Mya. Genus-level splits occurred in Gobiidae and Oxudercidae predominantly at Miocene and late Miocene to early Pleistocene, respectively. Gobies have likely originated in many parts of the northern and western Pacific Ocean, of which a large proportion of Oxudercidae have adapted to various environments in the North Pacific.

Background Primary squamous cell carcinoma (SCC) of the salivary gland is a rare disease, and distinguishing primary SCC from metastatic SCC is difficult. This study investigated the histological and immunohistochemical differences between primary and metastatic salivary gland SCC to improve the accuracy of diagnosis and to explore the pathogenesis of this disease. Methods Data of 16 patients who underwent surgery for SCC of salivary glands between 2000 and 2018 at Asan Medical Center were retrieved. Eight patients had a history of SCC at other sites, and eight patients had only salivary gland SCC. Immunostaining for p16, p53, androgen receptor (AR), gross cystic disease fluid protein 15 (GCDFP-15), and c-erbB2, as well as mucicarmine staining, were compared between the two groups. Results Most tumors were located in the center of the salivary glands with extraparenchymal extension. The histology of primary SCC of the salivary gland was consistent with moderately differentiated SCC with extensive desmoplastic reaction and peritumoral inflammation. Involvement of the salivary gland ducts and transition into the ductal epithelium were observed in two cases. Metastatic SCC resembled the primary tumor histologically and was associated with central necrosis. Both groups exhibited negative mucin staining. Two, one, and one primary SCC case exhibited AR, GCDFP-15, and c-erbB2 positivity, respectively. Conclusions A subset of primary SCCs originated in salivary ducts or was related to salivary duct carcinoma. Distinguishing primary from metastatic SCC of the salivary gland is difficult using histologic features and immunoprofiles. A comprehensive review of the medical history is essential.

Acid spills cause large-scale environmental damage and casualties. To respond to such incidents, a sensor capable of detecting acid leaks is required. Cellulose is a useful substrate material for the fast detection of acid leaks because it has high hydrophilicity and porosity. On the other hand, methods of manufacturing cellulose-based sensors are still complicated or time-consuming. Thus, in this study, a simple and rapid synthesis method for a cellulose-based pH sensor was proposed. The functionalization of α-cellulose was achieved via chloroacetyl chloride, and Congo red was covalently immobilized to the functionalized cellulose for detecting strong acids. The manufacturing process was composed of two steps as above and finished within 8 h. The developed sensor exhibited absorbance changes in the pH range of 0.2 to 3.0, and response time was shorter than 1 s. A prototype system using this sensor was manufactured and tested, and it detected acid leaks easily and quickly.

Abstract The current design codes discuss the effective compressive strengths of columns, which reflect a decrease in load transfer performance that can occur when columns and slabs have different concrete compressive strengths. The effective compressive strength of a column increases as it is confined by the slab, and the design codes mandate three different effective compressive strengths for interior columns (confinement on four sides), exterior columns (confinement on three sides), and corner columns (confinement on two sides). For both corner and exterior columns, the confinement effect of the slab is significantly smaller than that for the interior column, and there is a more marked decrease in load transfer performance. However, there is still a lack of theoretical studies investigating the effective compressive strengths of the corner and exterior columns. Therefore, based on the analysis model established in previous research, this study has proposed an equation for calculating the effective compressive strengths of the corner, exterior and isolated columns without any confinement effects of the slab. In addition, axial loading tests of isolated columns were conducted and the proposed equation was verified.

Background The worldwide incidence of squamous cell carcinoma of the tongue (SCCOT) in young patients has been increasing. We investigated clinicopathologic features of this unique population and compared them with those of SCCOT in the elderly to delineate its pathogenesis. Methods We compared clinicopathological parameters between patients under and over 45 years old. Immunohistochemical assays of estrogen receptor, progesterone receptor, androgen receptor, p53, p16, mdm2, cyclin D1, and glutathione S-transferase P1 were also compared between them. Results Among 189 cases, 51 patients (27.0%) were under 45 years of age. A higher proportion of women was seen in the young group, but was not statistically significant. Smoking and drinking behaviors between age groups were similar. Histopathological and immunohistochemical analysis showed no significant difference by age and sex other than higher histologic grades observed in young patients. Conclusions SCCOT in young adults has similar clinicopathological features to that in the elderly, suggesting that both progress via similar pathogenetic pathways.

This study aimed to evaluate the egress safety in nursing hospitals based on the capacity of the smoke exhaust system. To this end, the available safe egress time was calculated by analyzing changes in visibility, carbon monoxide, carbon dioxide, oxygen contents, and temperature depending on the fire duration. In addition, an egress simulation was performed using the number of workers (egress guides) and egress delay time as variables, and the required safe egress time was estimated. Based on the results, the egress safety of a prototype nursing hospital was evaluated. In this study, egress safety criteria to evaluate egress safety in a typical nursing hospital were presented, which are expressed in terms of normalized egress guides, the capacity ratio of the smoke exhaust system, and egress delay time. The proposed criteria can be used to evaluate the egress safety of typical nursing hospitals and to prepare complementary measures.

BackgroundCurrently, high-speed digital imaging (HSDI), especially endoscopic HSDI, is routinely used for the diagnosis of vocal cord disorders. However, endoscopic HSDI devices are usually large and costly, which limits access to patients in underdeveloped countries and in regions with inadequate medical infrastructure. Modern smartphones have sufficient functionality to process the complex calculations that are required for processing high-resolution images and videos with a high frame rate. Recently, several attempts have been made to integrate medical endoscopes with smartphones to make them more accessible to people in underdeveloped countries. ObjectiveThis study aims to develop a smartphone adaptor for endoscopes, which enables smartphone-based vocal cord imaging, to demonstrate the feasibility of performing high-speed vocal cord imaging via the high-speed imaging functions of a high-performance smartphone camera, and to determine the acceptability of the smartphone-based high-speed vocal cord imaging system for clinical applications in developing countries. MethodsA customized smartphone adaptor optical relay was designed for clinical endoscopy using selective laser melting–based 3D printing. A standard laryngoscope was attached to the smartphone adaptor to acquire high-speed vocal cord endoscopic images. Only existing basic functions of the smartphone camera were used for HSDI of the vocal cords. Extracted still frames were observed for qualitative glottal volume and shape. For image processing, segmented glottal and vocal cord areas were calculated from whole HSDI frames to characterize the amplitude of the vibrations on each side of the glottis, including the frequency, edge length, glottal areas, base cord, and lateral phase differences over the acquisition time. The device was incorporated into a preclinical videokymography diagnosis routine to compare functionality. ResultsSmartphone-based HSDI with the smartphone-endoscope adaptor could achieve 940 frames per second and a resolution of 1280 by 720 frames, which corresponds to the detection of 3 to 8 frames per vocal cycle at double the spatial resolution of existing devices. The device was used to image the vocal cords of 4 volunteers: 1 healthy individual and 3 patients with vocal cord paralysis, chronic laryngitis, or vocal cord polyps. The resultant image stacks were sufficient for most diagnostic purposes. The cost of the device including the smartphone was lower than that of existing HSDI devices. The image processing and analytics demonstrated the successful calculation of relevant diagnostic variables from the acquired images. Patients with vocal pathologies were easily differentiable in the quantitative data. ConclusionsA smartphone-based HSDI endoscope system can function as a point-of-care clinical diagnostic device. The resulting analysis is of higher quality than that accessible by videostroboscopy and promises comparable quality and greater accessibility than HSDI. In particular, this system is suitable for use as an accessible diagnostic tool in underdeveloped areas with inadequate medical service infrastructure.

Background: We investigated the combined effect of chronic kidney disease (CKD) and nonalcoholic fatty liver disease (NAFLD) on the risk of cardiovascular disease (CVD) in patients with type 2 diabetes. Methods: Data were obtained from the Korean National Health Insurance Service. Patients with diabetes who participated in health screenings from 2009 to 2011 were included. The fatty liver index (FLI) was used as a surrogate marker for NAFLD. Results: During a mean follow-up of 6.9 years, 40,863 incidents of myocardial infarction (MI), 58,427 strokes, and 116,977 deaths were reported in 1,607,232 patients with type 2 diabetes. After adjusting for conventional risk factors, patients with CKD and NAFLD showed the highest risk of MI and stroke (hazard ratio (HR) = 1.49; 95% confidence interval (CI): 1.42–1.57 and stroke, HR = 1.48; 95% CI: 1.41–1.54, respectively) compared with those without either CKD or NAFLD. Both overall and cardiovascular mortality were highest in the CKD/NAFLD group compared with other groups (HR = 2.00; 95% CI: 1.94–2.06, and HR = 2.20; 95% CI: 2.07–2.35, respectively). Advanced liver fibrosis was significantly associated with an increased risk of CVD in patients with NAFLD. Proteinuria was significantly associated with incidence of CVD events in patients with CKD. Conclusions: The combination of CKD and NAFLD was associated with an increased risk of CVD and mortality in patients with type 2 diabetes. Close monitoring and appropriate management of CKD and NAFLD may be warranted to prevent CVD in these patients.

Objectives The current study aims to determine the correlation between nutritional status upon presentation and disease severity, as well as treatment and survival outcomes. Methods Patients who were diagnosed with deep neck infection, underwent at least one surgical drainage/debridement, and had more than 1 week of hospitalization at a tertiary medical center from 2007 to 2015 were retrospectively included. Thereafter, initial serum albumin, C-reactive protein (CRP), and body mass index (BMI) were reviewed. Results A total of 135 patients were included in the final analysis. Accordingly, the proportion of patients with simultaneous mediastinitis (21.0%), necrotizing fasciitis (12.9%), disease extent >1 cervical level (72.6%), mean CRP (22.4 mg/dL), mean length of hospitalization (25.0 days), and mean 1-week follow-up CRP (7.2 mg/dL) was significantly higher in the hypoalbuminemia group (initial serum albumin 1 cervical level (2.12), initial serum CRP over 20 mg/dL (3.79), hospitalization of more than 14 days (4.10), 1-week follow-up CRP over 5 mg/dL (3.78), and increased duration for an over 50% decrease in initial CRP (2.70) (all P

Nursing hospitals have a high probability of casualties during a fire disaster because they have many patients with impaired mobility. In this study, fire and egress simulations were conducted to evaluate the egress safety of a typical nursing hospital. The available safe egress time (ASET) of the prototype nursing hospital was calculated using Fire Dynamics Simulator, and the required safe egress time (RSET) was estimated by Pathfinder, reflecting characteristics of the occupants. The egress safety of the nursing hospital was then evaluated by comparing the ASET and RSET, considering the number of egress guides and delay time. According to the simulation results, the RSET increased as the egress delay time increased and the number of egress guides decreased. In addition, it is estimated that at least 20 workers (egress guides) should be on duty in the prototype nursing hospital, even during shiftwork and night duty. Based on the simulation results, egress safety criteria have been proposed in terms of normalized numbers of egress guides and egress delay time. The proposed criteria can be very easily applied to evaluate the egress safety of a typical nursing hospital in operation.

(1) Background: Facial nerve resection with reconstruction helps achieve optimal outcomes in the treatment of facial nerve invasion (FNI) of parotid cancer. Preoperative imaging is crucial to predict facial nerve reconstruction. The radiological findings of CT or MRI may predict FNI in the parotid cancer even without facial paralysis. Methods: We retrospectively reviewed the records of 151 patients without facial nerve paralysis before surgery who had undergone tumor resection. Previously untreated parotid cancers were included. (2) Results: The median follow-up duration was 62 months (range: 24–120 months). The FNI (+) group (n = 30) showed a significantly worse 5-year overall survival compared with the FNI (−) group (75.5 vs. 93.9%; hazard ratio = 4.19; 95% confidence interval: 1.74–10.08; p = 0.001). The tumor margin, tumor size, presence in the anterolateral parotid region (area 3), retromandibular vein involvement, distance from the stylomastoid foramen to the upper tumor margin, and a high tumor grade were significant factors related to FNI in the univariate analysis. A spiculated tumor margin, the tumor size (2.2 cm), and presence in area 3 were factors predicting FNI in the logistic regression model (p = 0.020, 0.005, and 0.050, respectively; odds ratio: 4.02, 6.40, and 8.16, respectively). (3) Conclusions: The tumor size (≥2.2 cm), spiculated margin, and presence in area 3 as presented in CT and MRI may help clinicians preoperatively predict FNI in patients with parotid cancer and establish an appropriate surgical plan.

Herein, state-of-the-art research advances in South Korea regarding the development of chemical sensing materials and fully integrated Internet of Things (IoT) sensing platforms were comprehensively reviewed for verifying the applicability of such sensing systems in point-of-care testing (POCT). Various organic/inorganic nanomaterials were synthesized and characterized to understand their fundamental chemical sensing mechanisms upon exposure to target analytes. Moreover, the applicability of nanomaterials integrated with IoT-based signal transducers for the real-time and on-site analysis of chemical species was verified. In this review, we focused on the development of noble nanostructures and signal transduction techniques for use in IoT sensing platforms, and based on their applications, such systems were classified into gas sensors, ion sensors, and biosensors. A future perspective for the development of chemical sensors was discussed for application to next-generation POCT systems that facilitate rapid and multiplexed screening of various analytes.

Abstract In this study, prestressed hybrid wide flange (PHWF) composite girders were proposed, and full-scale flexural tests were conducted to evaluate their structural performances. This new proposed girder system was developed and designed to effectively resist external loads considering the actual construction sequences. Two specimens with and without shear connectors were fabricated and tested to examine the effect of the shear connectors for achieving the fully-composite behaviors between a cast-in-place (CIP) concrete and the prefabricated prestressed steel–concrete composite girder. The test results showed that sufficient flexural strengths and deformation capacities can be obtained in both types of PHWF composite girders with and without shear connectors. To reflect the actual construction stages of the proposed PHWF composite girder, nonlinear flexural analyses were proposed considering the prestress effect and segmental effect before and after composite with the CIP concrete, respectively. The observed and analysis results of strain behaviors of the PHWF girder specimens were also compared and discussed in detail.

In this study, full-scale fire tests and finite element (FE) analyses are conducted to investigate the fire resistance performance of hollow-core slabs (HCSs) manufactured using the extrusion method. The deflection of the HCS specimens and the temperature distribution in the section according to the fire exposure time are measured and analyzed comprehensively, and the test results are compared with the FE analysis results. In addition, parametric analyses are conducted on 21 cases with the HCS depth, span length, hollow ratio in a section, cover thickness of concrete, and load ratio (i.e., the ratio of the external load to the ultimate load) as variables, based on which the fire resistance performance of the HCS according to each variable is investigated. The analysis results show that the load ratio is a key factor governing the fire resistance behavior of HCSs, whereas the effects of the cover thickness of concrete and the hollow ratio in a section are relatively slight within the range of variables examined in this study.

Background Basaloid squamous cell carcinoma (BSCC) is a rare variant of squamous cell carcinoma with distinct pathologic characteristics. The histogenesis of BSCC is not fully understood, and the cancer has been suggested to originate from a totipotent primitive cell in the basal cell layer of the surface epithelium or in the proximal duct of secretory glands. Methods Twenty-six cases of head and neck BSCC from Asan Medical Center, Seoul, Korea, reported during a 14-year-period were subclassified into basal, ductal, and mixed subtypes according to the expression of basal (cytokeratin [CK] 5/6, p63) or ductal markers (CK7, CK8/18). The cases were also subject to immunohistochemical study for CK19, p53, cyclin D1, epidermal growth factor receptor (EGFR), and p16 and to in situ hybridization for human papillomavirus (HPV), and the results were clinico-pathologically compared. Results Mixed subtype (12 cases) was the most common, and these cases showed hypopharyngeal predilection, older age, and higher expression of CK19, p53, and EGFR than other subtypes. The basal subtype (nine cases) showed frequent comedo-necrosis and high expression of cyclin D1. The ductal subtype (five cases) showed the lowest expression of p53, cyclin D1, and EGFR. A small number of p16- and/or HPV-positive cases were not restricted to one subtype. BSCC was the cause of death in 19 patients, and the average follow-up period for all patients was 79.5 months. Overall survival among the three subtypes was not significantly different. Conclusions The results of this study suggest a heterogeneous pathogenesis of head and neck BSCC. Each subtype showed variable histology and immunoprofiles, although the clinical implication of heterogeneity was not determined in this study.

In this study, experimental tests were performed to evaluate the shear performance of encased steel truss (EST) composite girders that can resist loads at construction and composite stages. Four full-scale EST composite girders were fabricated, where the truss type (Pratt truss and Warren truss) and presence of stirrups were set as main test variables. The test results showed that in specimens applied with the Pratt truss, horizontal shear cracking occurring along the interface between concrete and steel was the dominant failure mode. Based on the crack pattern and failure plane observed from the test, the horizontal shear strengths of the Pratt truss specimens were calculated, which provided conservative results. On the other hand, in the specimens with the Warren truss inside, the strengths of the specimens were governed by the shear failure occurring in the screw rod connecting the truss elements prior to the yielding of the diagonal member. The shear strengths of the Warren truss specimens calculated based on the shear failure of the screw rod were similar to that obtained from the test.

This study describes a unique case of single mucin-rich brain metastasis in a patient with breast cancer, mimicking the T2-fluid attenuation inversion recovery (FLAIR) mismatch sign and masquerading as an isocitrate dehydrogenase-mutant astrocytoma. This case highlights the importance of considering mucin-rich lesions in the differential diagnosis of intracranial tumors exhibiting T2-FLAIR mismatch. Clinicians must recognize the potential convergence in imaging characteristics between these metastases and gliomas to guarantee prompt and accurate patient care.

BackgroundIn endoscopic sinus surgery, visualization of the surgical field is a major concern, as surgical bleeding is the cause of many complications. The purpose of this study was to compare the effects of dexmedetomidine and remifentanil on the visualization of the surgical field in endoscopic sinus surgery.MethodsForty-three patients were prospectively enrolled and randomly allocated to the dexmedetomidine or remifentanil group and general anesthesia was induced and maintained using a propofol target-controlled infusion. In the dexmedetomidine group, dexmedetomidine was loaded for 5 min and a continuous infusion was administered. In the remifentanil group, a remifentanil target-controlled infusion was used. After completion of the operation, the satisfaction with the visualization of the surgical field was assessed on a numeric rating scale, from 0 (= worst) to 10 (= best). The mean blood pressure, heart rate, recovery profiles, and postoperative pain score were recorded.ResultsSatisfaction score for visualization by numeric rating scale was not significantly different between the two groups (P = 0.95). There were no differences in the mean blood pressure and heart rate. The extubation time was significantly shorter in the dexmedetomidine group (8.4 ± 1.8 min) than in the remifentanil group (11.9 ± 5.4 min) (P = 0.04). Except for the extubation time, the recovery profiles of the two groups were comparable.ConclusionsContinuous infusions of dexmedetomidine provide a similar visualization of the surgical field and hemodynamic stability as remifentanil target-controlled infusions in patients undergoing endoscopic sinus surgery.

In the current design codes, the effective compressive strength can be used to reflect decrease in load-transfer performance when upper/lower columns and slabs have different concrete compressive strengths. In this regard, this study proposed a method that can accurately estimate the effective compressive strengths by using an adaptive neuro-fuzzy inference system (ANFIS). The ANFIS is an algorithm that introduces a learning system that corrects errors into a fuzzy theory and has widely been used to solve problems with complex mechanisms. In order to constitute the ANFIS algorithm, 50 data randomly extracted from 75 existing test datasets were used in training, and 25 were used for verification. It was found that analysis using the ANFIS model provides a more accurate evaluation of the effective compressive strengths of corner and edge columns than do the equations specified in the current design codes. In addition, parametric studies were performed using the ANFIS model, and a simplified equation for calculating the effective compressive strength was proposed, so that it can be easily used in practice.

In recent years, a variety of strengthening methods have been developed to improve the seismic performance of reinforced concrete (RC) frame structures with non-seismic details. In this regard, this study proposes a new type of seismic strengthening method that compresses prefabricated precast concrete (PC) walls from the outside of a building. In order to verify the proposed method, a RC frame structure strengthened with precast walls was fabricated, and cyclic loading tests were performed. The results showed that specimens strengthened using the proposed method exhibited further improvements in strength, stiffness and energy dissipation capacity, compared to RC frame structures with non-seismic details. In addition, a nonlinear analysis method, capable of considering the flexural compression and shear behaviors of the walls, was suggested to analytically evaluate the structural behavior of the frame structures strengthened by the proposed method. Using this, an analysis model for frame structures strengthened with precast walls was proposed. Through the proposed model, the analysis and test results were compared in relation to stiffness, strength, and energy dissipation capacity. Then, the failure mode of the column was evaluated based on the pushover analysis. In addition, this study proposed a simplified analysis model that considered the placement of longitudinal reinforcements in shear walls.

Half precast concrete slabs with inverted multi-ribs (Joint Advanced Slab, JAS), which enhance composite performance between slabs by introducing shear keys at connections between the slabs and improve structural performance by placing prestressing tendons and truss-type shear reinforcements, have recently been developed and applied in many construction fields. In this study, flexural and shear tests were performed to verify the structural performance of JAS members. Towards this end, two flexural specimens and four shear specimens were fabricated, and the presence of cast-in-place concrete and the location of the critical section were set as the main test variables. In addition, the flexural and shear performance of the JAS was quantitatively evaluated using a non-linear flexural analysis model and current structural design codes. Evaluation results confirmed that the flexural behavior of the JAS was almost similar to the behavior simulated through the non-linear flexural analysis model, and the shear performance of the JAS can also be estimated appropriately by using the shear strength equations presented in the current design codes. For the JAS with cast-in-place concrete, however, the shear strength estimation results differed significantly depending on the way that the shear contributions of the precast concrete unit and cast-in-place concrete were calculated. Based on the analysis results, this study proposed a design method that can reasonably estimate the shear strength of the composite JAS.

Background: Core needle biopsy is a relatively new technique used to diagnose salivary gland lesions, and its role in comparison with fine needle aspiration cytology needs to be refined. Methods: We compared the results of 228 ultrasound-guided core needle biopsy and 371 fine needle aspiration procedures performed on major salivary gland tumors with their postoperative histological diagnoses. Results: Core needle biopsy resulted in significantly higher sensitivity and more accurate tumor subtyping, especially for malignant tumors, than fine needle aspiration. No patient developed major complications after core needle biopsy. Conclusions: We recommend ultrasoundguided core needle biopsy as the primary diagnostic tool for the preoperative evaluation of patients with salivary gland lesions, especially when malignancy is suspected.

ObjectivesThe purpose of this study was to evaluate the usefulness of retroauricular hair line incision (RAHI) in partial superficial parotidectomy by comparison with modified Blair incision or facelift incision.MethodsMedical records of 73 patients with benign parotid tumor who underwent partial superficial parotidectomy were retrospectively reviewed. Size and location of tumors, operative time, occurrence of facial nerve paralysis and Frey's syndrome, and cosmetic outcomes were compared among RAHI, facelift incision (FLI), modified Blair incision (MBI) groups.ResultsRAHI group showed better cosmetic results than FLI group or MBI group compared with other type of incisions (P0.999), occurrence of temporary or permanent facial nerve paralysis (P=0.745) and Frey's syndrome (P=0.940).ConclusionPartial superficial parotidectomy can be done safely by RAHI in most cases of benign parotid tumor. Compared with MBI or FLI, RAHI has better cosmetic outcome with no increase of operative time or postoperative complications.

ObjectivesThis study evaluated the risk factors for anastomotic leakage (AL) and survival outcomes in patients with head and neck squamous cell carcinoma (HNSCC).MethodsPatients with HNSCC who underwent surgery carrying potential AL from 2003 through 2009 were included in this study. Univariate and multivariate analyses were performed and patient survival was calculated by the Kaplan-Meier method.ResultsOf 232 eligible patients, 25 (10.8%) developed AL. Univariate analyses revealed that primary tumor site, salvage surgery, perineural invasion, radiotherapy, chemotherapy, and blood transfusion were significantly associated with the occurrence of AL (P0.1).ConclusionPatients who received salvage surgery and blood transfusion may require careful surveillance for development of AL, which has a tendency toward decreased survival.

Two species of small gobiid fishes genus Luciogobius, i.e., L. elongatus, L. platycephalus were described as the first records from Korea based on specimens collected from gravel beaches of Gijang-gun, Busan-si, Korea. Luciogobius elongatus is distinguished from congeners by very elongated and naked body, 42-44 vertebrae, 6-7 dorsal soft rays, and no free rays on pectoral fin, and L. platycephalus is characterized by having very depressed head, naked body, 40-41 vertebrae, 10-11 dorsal soft rays, and pectoral fin with only upper 2-4 free rays. We propose the new Korean name “Ga-neun-mi-kkeun-mang-dug”, “Nab-jak-mi-kkeunmang- dug” for L. elongatus and L. platycephalus, respectively.

The complete mitochondrial genomes of Luciogobius grandis and Luciogobius elongatus (Perciformes, Gobionellinae) living on rocky coasts in South Korea are reported here for the first time. The mitogenomes of L. grandis and L. elongatus have total lengths of 16,477 bp and 16,486 bp, respectively, and include 13 PCGs, small and large rRNAs, a control region, and 22 tRNAs. Most of the genes are encoded on the heavy strand except for nine genes. Compared with other Gobionellinae species, the PCGs of the two Luciogobius species have a conserved gene order. These data provide useful molecular information for phylogenetic studies concerning Luciogobius species and related species.

Precise evaluation of the tympanic membrane (TM) is required for accurate diagnosis of middle ear diseases. However, making an accurate assessment is sometimes difficult. Artificial intelligence is often employed for image processing, especially for performing high level analysis such as image classification, segmentation and matching. In particular, convolutional neural networks (CNNs) are increasingly used in medical image recognition. This study demonstrates the usefulness and reliability of CNNs in recognizing the side and perforation of TMs in medical images. CNN was constructed with typically six layers. After random assignment of the available images to the training, validation and test sets, training was performed. The accuracy of the CNN model was consequently evaluated using a new dataset. A class activation map (CAM) was used to evaluate feature extraction. The CNN model accuracy of detecting the TM side in the test dataset was 97.9%, whereas that of detecting the presence of perforation was 91.0%. The side of the TM and the presence of a perforation affect the activation sites. The results show that CNNs can be a useful tool for classifying TM lesions and identifying TM sides. Further research is required to consider real-time analysis and to improve classification accuracy.

In this study, shear tests were conducted to investigate the effects of longitudinal reinforcement corrosion on the shear capacity of reinforced concrete (RC) members with transverse reinforcement. To this end, a total of eight test specimens were fabricated, and the corrosion rates and anchorage details of rebars were set as test variables. In addition, an accelerated corrosion technique was used to introduce corrosion into the longitudinal reinforcement without corroding shear reinforcement. The test results indicated that the capacities of the specimens in which tension reinforcement was not properly anchored at the ends of the members decreased rapidly at high corrosion rates, whereas the capacities of the specimens in which tension reinforcement was properly anchored by hooks were similar to or higher than those of the non-corroded specimens, despite bond loss caused by corrosion.

Fresh concrete used in 3D printing should ensure adequate yield stress, otherwise the printed concrete layer may suffer intolerable deformation or collapse during the printing process. In response to this issue, an analytical study was carried out to derive the initial yield stress and hardening coefficient of fresh concrete suitable for 3D printing. The maximum shear stress distribution of fresh concrete was calculated using a stress transformation equation derived from the equilibrium condition of forces. In addition, the elapsed time experienced by fresh concrete during the printing processes was estimated and was then substituted into the elapsed time-yield stress function to calculate the yield stress distribution. Based on these results, an algorithm capable of deriving both the initial yield stress and the hardening coefficient required for printing fresh concrete up to the target height was proposed and computational fluid dynamics (CFD) analyses were performed to verify the accuracy of the proposed model.

Gobiids are hyperdiverse compared with other teleost groups, with about 2,000 species occurring in marine, freshwater, and blackish habitats, and they show a remarkable variety of morphologies and ecology. Testing the effectiveness of DNA barcodes on species that have emerged as a result of radiation remains a major challenge in evolutionary biology. Here, we used the cytochrome c oxidase subunit 1 (COI) sequences from 144 species of gobies and related species to evaluate the performance of distance-based DNA barcoding and to conduct a phylogenetic analysis. The average intra-genus genetic distance was considerably higher than that obtained in previous studies. Additionally, the interspecific divergence at higher taxonomic levels was not significantly different from that at the intragenus level, suggesting that congeneric gobies possess substantial interspecific sequence divergence in their COI gene. However, levels of intragenus divergence varied greatly among genera, and we do not provide sufficient evidence for using COI for cryptic species delimitation. Significantly more nucleotide changes were observed at the third codon position than that at the first and the second codons, revealing that extensive variation in COI reflects synonymous changes and little protein level variation. Despite clear signatures in several genera, the COI sequences did resolve genealogical relationships in the phylogenetic analysis well. Our results support the validity of COI barcoding for gobiid species identification, but the utilization of more gene regions will assist to offer a more robust gobiid species phylogeny.

A three specimen of Icelus toyamensis, belonging to Cottidae, Scorpaeniformes, was firstly collected from the East Sea, Korea during 2007-2009. We herein described the species as the first record from Korea on the basis of these specimens. Icelus toyamensis is characterized by the following morphological combinations: spinous scales absent on the base of dorsal fin; small ctenoid scales scattered on body sides; gill rakers are short, tubular, and relatively broad; the uppermost preopercular spine is sharp and simple; dorsal fin rays VIII-IX, 20-21; anal fin soft rays 18-19; pectoral fin rays 18, and vertebrae 40-41. New Korean name of I. toyamensis is proposed as “Min-jul-ga-si-hoet-dae.”

ObjectivesThe aims of this study were to evaluate the prevalence of otolaryngologic diseases in Korea.MethodsWe obtained data from the 2008 Korea National Health and Nutrition Examination Surveys (KNHANES), which were cross-sectional surveys of the civilian, non-institutionalized population of South Korea (n=4,930). A field survey team that included an otolaryngologist, nurses, and interviewers moved with a mobile examination unit and performed otolaryngologic interviews and physical examinations.ResultsThe prevalence of subjective hearing loss, tinnitus, preauricular fistua, tympanic membrane perforation, and cholesteatoma were 11.97%, 20.27%, 2.08%, 1.60%, and 1.18%, respectively. Dizziness and vestibular dysfunction were common among Korean adults, since 23.33% of the participants reported symptoms of dizziness or imbalance, and the prevalence of vestibular dysfunction was 3.86%. The prevalence of nasal diseases was relatively high, as the prevalence of allergic rhinitis, chronic rhinosinusitis, and a deviated nasal septum were 28.01%, 7.12%, and 42.94%, respectively. Subjective dysphonia was found in 6.60% of the participants, and the prevalence of subjective dysphonia increased with age.ConclusionThis is the first nation-wide epidemiologic study to assess the prevalence of otolaryngologic diseases by both the Korean Otolaryngologic Society and the Ministry of Health and Welfare. Considering the high prevalence of otolaryngologic diseases in Korea, the results call for additional studies to better prevent and manage otolaryngologic diseases.

ObjectivesThe clinical utility of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been demonstrated in major head and neck cancers (HNCs) but is unclear in rare HNCs. We therefore evaluated FDG PET in the management of patients with rare HNCs.MethodsFDG PET and CT/MRI scanning were performed at the initial staging and/or the follow-up in 24 patients with rare HNCs, 10 with melanoma, 9 with sarcoma, 3 with olfactory neuroblastomas, and 2 with basal cell carcinoma. The diagnostic accuracy of CT and FDG PET for detecting primary tumors and metastases were compared with a histopathologic reference. The association between the PET results and the clinicopathologic parameters predicting tumor invasion, histologic grade and disease-free survival (DFS), was assessed.ResultsThe overall accuracies of FDG PET and CT/MRI were 92% and 79%, respectively, for detecting primary tumors and 91% and 74%, respectively, for nodal metastases, but the differences were not significant due to the small number of patients. The sensitivity and specificity of FDG PET for detecting distant metastases and second primary tumors were 100% and 87%, respectively. Follow-up FDG PET correctly diagnosed locoregional recurrence in all 12 patients, as shown by biopsy, and distant metastases in 6 patients. However, thickness of melanoma, histologic grade of sarcoma, and DFS were not associated with tumor FDG uptake.ConclusionFDG PET may be useful for staging, posttreatment monitoring, and detection of distant metastases and second primary tumors in patients with rare HNCs.

Primary synovial sarcoma of the thyroid is an extremely rare condition which has only been reported twice in the literature. We herein report a case of highly aggressive and rapidly lethal primary synovial sarcoma of the thyroid. A 72-year-old woman presented with extensive local invasion, rapid progression, and early distant metastasis secondary to primary thyroid synovial sarcoma. The tumor exhibited an atypical histologic and immunohistochemical staining pattern. Detection of SYT/SSX fusion transcript confirmed the diagnosis of synovial sarcoma. Due to the aggressive nature of primary synovial sarcoma of the thyroid gland, early diagnosis and comprehensive treatment including wide resection and postoperative chemoradiation is required.

Waste from non-degradable packaging materials poses a serious environmental risk and has led to interest in developing sustainable bio-based packaging materials. Sustainable packaging materials have been made from diverse naturally derived materials such as bamboo, sugarcane, and corn starch. In this study, we made a sustainable packaging film using chitosan extracted from the biomass of yellow mealworm (Tenebrio molitor) shell waste. The extracted chitosan was used to create films, cross-linked with citric acid (CA) and with the addition of glycerol to impart flexibility, using the solvent casting method. The successful cross-linking was evaluated using Fourier-Transform Infrared (FTIR) analysis. The CA cross-linked mealworm chitosan (CAMC) films exhibited improved water resistance with moisture content reduced from 19.9 to 14.5%. Improved barrier properties were also noted, with a 28.7% and 10.2% decrease in vapor permeability and vapor transmission rate, respectively. Bananas were selected for food preservation, and significant changes were observed over a duration of 10 days. Compared to the control sample, bananas packaged in CAMC pouches exhibited a lesser loss in weight because of excellent barrier properties against water vapor. Moreover, the quality and texture of bananas packaged in CAMC pouch remained intact over the duration of the experiment. This indicates that adding citric acid and glycerol to the chitosan structure holds promise for effective food wrapping and contributes to the enhancement of banana shelf life. Through this study, we concluded that chitosan film derived from mealworm biomass has potential as a valuable resource for sustainable packaging solutions, promoting the adoption of environmentally friendly practices in the food industry.

Background/Aims: The pathophysiology of lean nonalcoholic fatty liver disease (NAFLD) is unclear but has been shown to be associated with more diverse pathogenic mechanisms than that of obese NAFLD. We investigated the characteristics of genetic or metabolic lean NAFLD in a health checkup cohort. Methods: This retrospective cross-sectional study analyzed single nucleotide polymorphism data for 6,939 health examinees. Lean individuals were categorized according to a body mass index cutoff of 23 kg/m² . Single nucleotide polymorphisms were analyzed using genotyping arrays. Results: The prevalence of lean NAFLD was 21.6% among all participants with NAFLD, and the proportion of lean NAFLD was 18.5% among lean participants. The prevalence of metabolic syndrome and diabetes among lean patients with NAFLD was 12.4% and 10.4%, respectively. Lean NAFLD appeared to be metabolic-associated in approximately 20.1% of patients. The homozygous minor allele (GG) of PNPLA3 (rs738409) and heterozygous minor alleles (CT, TT) of TM6SF2 (rs58542926) were associated with lean NAFLD. However, the prevalence of fatty liver was not associated with the genetic variants MBOAT7 (rs641738), HSD17B13 (rs72613567), MARC1 (rs2642438), or AGXT2 (rs2291702) in lean individuals. Lean NAFLD appeared to be associated with PNPLA3 or TM6SF2 genetic variation in approximately 32.1% of cases. Multivariate risk factor analysis showed that metabolic risk factors, genetic risk variants, and waist circumference were independent risk factors for lean NAFLD. Conclusions: In a considerable number of patients, lean NAFLD did not appear to be associated with known genetic or metabolic risk factors. Further studies are required to investigate additional risk factors and gain a more comprehensive understanding of lean NAFLD. [ABSTRACT FROM AUTHOR]