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We report a delayed postoperative injury to the esophagus in a patient who underwent cervical corpectomy for spondylodiscitis. The patient was a 72-year-old man. He was diagnosed by magnetic resonance imaging with spondylodiscitis at C5/6/7, with an epidural abscess at C5/6/7, and ossification of the posterior longitudinal ligament from C2 to C7. For surgical treatment, corpectomy and interbody fusion with a mesh cage at C5/6, an anterior plate and posterior laminectomy at C3/4, posterior screw fixation at C5/6/7/T1, and anterior cervical discectomy and fusion at C3/4 were performed. After 2 weeks, blood was detected in the Levin tube drain and gastroscopy was performed. Gastroscopy confirmed that the mesh cage was exposed because of damage to the esophagus.

The water distribution system (WDS) abnormal condition detection is a technology that identifies WDS failure (e.g., pipe bursts) based on abnormal hydraulic behaviors. Its performance in detecting abnormal conditions is impacted by the quantity and quality of the collected hydraulic data. The hydraulic data for normal operation conditions could be provided using the measurements collected by smart meters and various other sensors. However, the abnormal condition hydraulic data cannot be obtained except by means of field tests and irregular system failures. Therefore, this study proposes three data generation approaches that utilize the following: (1) a hydraulic simulation model; (2) real-field WDS abnormal condition data (e.g., field tests, past failure data); and (3) both (1) and (2), simultaneously. Subsequently, the J-town network was applied in order to verify the proposed approaches. It was found that these approaches can generate synthetic failure data when considering the characteristics of actual events of failure and various other scenarios.

This study developed a vulnerability evaluation framework for earthquake and flood disasters targeting water treatment facilities. The vulnerability evaluation framework of a water treatment facility determines vulnerability evaluation factors such as exposure, sensitivity, and adaptive capacity in consideration of the characteristics of an environmental facility. At this time, vulnerability evaluation items are derived in consideration of topography, natural environment, hydraulic, structural, and non-structural characteristics by analyzing the facility. The vulnerability evaluation items consist of 24 for earthquake disasters, and for the flood disaster derived 20 indicators. Then the final vulnerability of disaster is determined by considering the impact of each item. To verify the vulnerability evaluation framework proposed in this study, the technology was applied to a real water treatment facility in Korea. The proposed technique would be able to make a plan to prevent natural disasters damage and minimize such damage to the environmental facility.

Leakage is one of the abnormal conditions in water distribution systems (WDSs). Real-time monitoring can be used to prevent or recover quickly from leakage. However, this is not enough: for improved leakage detection, a status diagnosis of the WDS must be performed together with this real-time monitoring, and numerous studies have been conducted on this. Furthermore, the existing proposed methodology only provides optimal sensor location and fast recognition. This paper proposes a technique that can quantitatively evaluate the volume of leakage along with leakage detection using deep learning technology. The hydraulic data (e.g., pressure, velocity, and flow) from the calibrated hydraulic model were used as training data and deep learning techniques were applied to conduct a simultaneous detection of leakage volume and location. We examined various scenarios regarding leakage volume and location for the data configuration of a simulated leakage accident. Furthermore, for optimal leakage detection performance, the detection performance according to the size of the network, the meter types of meters, the number of meters, and the locations of the meters were analyzed. This study is expected to be helpful in various aspects such as recovery and restoration decision making after leakage, because it simultaneously identifies the amount and location of the leakage.

Recently, due to extreme climate change, damage from flooding has been increasing; however, water shortages are being announced simultaneously. Moreover, the water distribution system’s ability to supply consumers is being overwhelmed because of urbanization, population concentration, and increases in water consumption. For this reason, to solve the water shortage problem, water reuse technologies are developing and improving that perform simple chemical treatment processes to reuse water for flushing toilets, washing, gardening, etc. but not as drinking water. However, most water reuse systems are designed and operated as independent systems, such as reusing water used in individual buildings or using rainwater. Therefore, this study develops an optimal design for the combined water systems, which is modeling and designing water distribution systems, urban drainage systems, and water reuse systems simultaneously to solve the water shortage and reduce flooding damage. To consider the combined water systems design, the existing water distribution system (WDS) demand is divided into drinking water and other uses, and the resource of other water is assumed by the rainwater storage tank for covering the amount of exceeding precipitation. To derive optimal design solutions for the combined three water systems, single- and multi-objective optimization techniques are applied considering various design criteria (i.e., construction cost, system resilience, and flooding volume on the exceeding design rainfall intensity). The developed combining water system design techniques could be used to create designs that solve the problems of medium and long-term water shortages and sustainable water systems development.

Water distribution systems (WDSs) are designed for supplying safe water under abnormal conditions. Therefore, the optimal design of WDSs should present a plan that satisfies the hydraulic constraint, pressure at the node, and flow rate of the pipe. The water quality constraint, that is, the residual chlorine standard, should be also satisfied. However, there is a problem of insufficient pressure or absence of water for the rapid increase in demand and abnormal situations caused by the destruction of pipes resulting from growing urbanization. This problem differs in node pressure and residence time, depending on the type of WDSs (i.e., loop, hybrid, and branch). Therefore, in this study, the optimal design of WDSs was determined by considering the form of the WDS and the residual chlorine concentration. To construct the layout of WDSs, the type was constructed and classified using the branch index, classification index, and hydraulic water-quality characteristics, which were analyzed accordingly. In addition, the objectives of the WDSs in terms of hydraulic (i.e., nodal pressure) and water-quality (i.e., reference values of residual chlorine concentrations) constraints were established to derive optimal designs that simultaneously stabilize and satisfy water. To stably supply water to the customer even in abnormal situations, an optimal multipurpose design was carried out by setting the sum of the surplus head and design cost as an objective function. These analyses can improve the water quality by simultaneously considering the residual chlorine concentration. They improved the hydraulic characteristics by considering only pressure in the existing design stage. In addition, by deriving an optimal design plan in terms of hydraulic quality according to topological features, we can derive an optimal design that assists the designer in decision making while improving the economic aspect and usability for the consumer.

Background: Acneiform eruption is the most common cutaneous adverse event associated with cetuximab. As it can affect quality of life and adversely affect chemotherapy schedule, additional medical care is required. Objectives: To investigate the adherence to and the duration of antibiotic administration to treat cetuximab-induced acneiform eruption. Methods: Medical data of patients who were referred to the Department of Dermatology were reviewed from January 2013 to June 2018. Dermatologists assessed the severity of acneiform eruption and prescribed tetracycline-class antibiotics according to the severity every 2 or 4 weeks. We investigated the duration and amount of oral antibiotic administration and analyzed the factors that may affect the control of acneiform eruption statistically. Results: A total of 207 of 267 patients referred to the Department of Dermatology showed acneiform eruption; 124 patients were treated with minocycline, 34 patients with doxycycline, 27 patients with both, and 22 patients with topical agents. The mean duration of oral antibiotic medication was 82.7 days. A statistical analysis of the factors that prolonged the use of antibiotics for more than 90 days showed that male and younger age were risk factors. Shorter time interval from starting cetuximab to starting antibiotics was associated with longer duration of antibiotic use, statistically. Conclusions: Cetuximab-induced acneiform eruption can be well controlled with tetracycline-class antibiotics in about 3 months. It can last longer in male and younger patients. The sooner and the more severe it appears, the longer it can last.

In recent years, Cyber-Physical Systems (CPSs) have been applied to Water Distribution Systems (WDSs) to facilitate efficient operation and maintenance. Since data are transmitted through the network in such systems, a cyberattack can disrupt the operation of WDSs, for example, by causing water supply reduction, water pollution, and economic losses. In the past few years, cyberattack detection algorithms and various cyberattack scenarios have been proposed. These studies considered either hydraulic factors, such as pipe velocity, nodal pressure, or tank level, or water quality factors. However, an algorithm which considers only one factor cannot prevent the various problems that may arise, such as water quality issues, and the hydraulic and quality factors have a correlation. Therefore, in this study, a framework was developed by considering both hydraulic and water quality factors. The proposed approach was applied to an artificial neural network model. Performance indicators were used to examine the detection performance according to the parameters of the artificial neural network. By comparing the detection performance when only hydraulic factors were considered and the performance when both hydraulic and water quality factors were considered, the effectiveness of the algorithm that consider both hydraulic and water quality factors was demonstrated. A cyberattack detection algorithm that considers both hydraulic and water quality criteria can be applicable in more realistic scenarios and contribute to the establishment of safe infrastructure for the entire process of designing and operating WDSs with CPSs.

The Kori-Unit 1 nuclear power plant, which is scheduled to be decommissioned after permanent shutdown, is expected to generate large amounts of various types of radioactive waste during the decommissioning process. Among these, nuclear reactors and internal structures have high levels of radioactivity and the dismantled structure must have the proper size and weight on the primary side. During decommissioning, it is important to prepare an appropriate and efficient disposal method through analysis of the disposal status and the legal restrictions on wastes generated from the reactors and internal structures. Nuclear reactors and internal structures generate radioactive wastes of various levels, such as medium, very low, and clearance. A radiation evaluation indicates that wastes in the clearance level are generated in the reactor head and upper head insulation. In this study, a clearance waste safety evaluation was conducted using the RESRAD-RECYCLE code, which is a safety evaluation code, based on the activation evaluation results for the clearance level wastes. The clearance scenario for the target radioactive waste was selected and the maximum individual and collective exposure doses at the time of clearance were calculated to determine whether the clearance criteria limit prescribed by the Nuclear Safety Act was satisfied. The evaluation results indicated that the doses were significantly low, and the clearance criteria were satisfied. Based on the safety assessment results, an appropriate metal recycle and disposal method were suggested for clearance, which are the subject of the deregulation of internal structures of nuclear power plant.

In recent years, significant attentions have been devoted to design of metaheuristic optimization algorithms in order to solve optimization problems. Metaheuristic optimizers are methods which are inspired by observing the phenomena occurring in nature. In this paper, a comprehensive and exhaustive review has been carried out on water cycle algorithm (WCA) and its applications in a wide variety of study fields. The WCA is one of the novel metaheuristic optimization algorithms which is inspired by water cycle process in nature and how streams and rivers flow into the sea. Good exploitation and exploration capabilities have made the WCA a good alternative for solving large-scale optimization problems. Due to its capabilities and strengths, the WCA has been utilized in many and various majors including mechanical engineering, electrical and electronic engineering, civil engineering, industrial engineering, water resources and hydropower engineering, computer engineering, mathematics, and so forth. A variety of articles based on WCA have been published in different international journals such as Elsevier, Springer, IEEE Transactions, Wiley, Taylor & Francis, and in the proceedings of international conferences as well, since 2012 to the present. Thus, it is highly believed that this paper can be appropriate, beneficial and practical for students, academic researchers, professionals, and engineers. Also, it can be an innovative and comprehensive reference for subsequent academic papers and books relevant to the WCA, optimization methods, and metaheuristic optimization algorithms.

자살사고는 자살 관련 행동의 주요한 예측변인으로 알려져 왔다. 한국어판 벡자살사고척도는 자살사고의 여부와 심각도를 평가하기 위해 개발된 도구이다. 본 연구는 한국 성인 집단을 대상으로 한국어판 벡자살사고척도의 심리측정적 속성을 검증하고자 하였다. 연구에 포함된 참가자들은 전국 16개 시도 소재의 지역사회에 거주하는 일반 성인 539명이었으며, 그 중에서 여성의 비율은 71.4%로 나타났다. 내적 일관성과 공존타당도를 검증하였으며, 구조타당도를 검증하기 위해 일련의 분석을 실시하였다. 요인수효의 범위를 탐색하기 위해 카이저 기준, 스크리 검사와 최소계수 요인분석에 기반한 평행분석을 실시하였다. 한국 성인 집단을 대상으로 한 척도의 내적 요인구조를 검증하기 위해 탐색적 구조방정식 모형 분석을 실시하였다. 내적 일관성은 우수한 수준으로 확인되었으며 자살사고에 대한 위험요인으로 알려진 우울, 불안, 절망을 측정하는 다른 설문과 유의미한 정적 상관을 나타냈다. 1요인과 2요인 모형에 대한 탐색적 구조방정식 모형 분석 결과, 한국 성인 집단 표본에서 벡자살사고척도는 2요인 구조가 가장 적합한 요인 구조로 나타났다. 각 요인에 부하된 문항들을 고려하여 2요인을 각각 (1) 자살에 대한 동기와 (2) 자살에 대한 준비로 명명하였다. 본 연구결과는 한국어판 벡자살사고척도가 한국 일반 성인들의 자살사고를 평가하고 이해하는데 있어 신뢰로운 도구임을 시사한다. 추후 연구에서는 임상 집단과 청소년 집단을 대상으로 이러한 결과가 일반화 될 수 있는지 추가적인 검토가 필요하겠다.

The goal of the present study was to evaluate the psychometric properties of the Suicide Screening Questionnaire-Self-Rating (SSQ-SR). A 25-item SSQ-SR is a newly developed suicide screening tool that measures suicide risk factors, including a history of suicidal thoughts and behaviors (STBs), life stress, and mental health problems. To investigate the reliability and validity of the SSQ-SR, we conducted a longitudinal case-control study with adults with and without STBs in the past six months. A total of 176 participants were recruited through 12 hospital-based Crisis Response Centers across South Korea. At the baseline, we administered the SSQ-SR, the Beck Scale for Suicide Ideation (BSSI), and the Patient Health Questionnaire-9 (PHQ-9). In a 6-months follow-up, we investigated whether the participants engaged in suicidal ideation, plan, or attempt since the baseline assessment. As a result, the SSQ-SR demonstrated a strong internal consistency (Cronbach's alpha coefficient = 0.96). In addition, the total score of SSQ-SR had concurrent validity compared to the total scores of the BSSI and the PHQ-9. In comparing the suicidal groups with the control group, the ROC analysis indicated the optimal cut point at 31 with a sensitivity rate of 0.97 and a specificity rate of 0.98. Through explanatory factor analysis, two factors were identified: Mental Health and Environmental Factors and Active Suicidal Thoughts and Behaviors. The SSQ-SR total and sub-factor scores were prospectively associated with subsequent suicidal ideation, plan, and attempt. These findings support that the SSQ-SR is a promising tool in prospectively screening those who are at risk of suicidal thoughts, plans, and nonfatal attempts.

Aim As the geriatric population increased, the need of treatment for laryngeal atrophy and dysfunction increased. This study was performed to evaluate the effects of injection of human adipose-derived stem cell (hASC) spheroid-loaded catechol-conjugated hyaluronic acid (HA-CA) hydrogel on therapeutic rejuvenation of the geriatric larynx. Methods Stem cell spheroids with hyaluronic acid-based hydrogel were injected into the laryngeal muscles of 18-month-old Sprague–Dawley rats. The effects of hASC spheroids were examined in the following four groups: SHAM, injected with PBS; GEL, injected with HA-CA hydrogel; MONO, injected with single hASCs in HA-CA hydrogel; and SP, injected with hASCs spheroids in HA-CA hydrogel. The rejuvenation efficacy in geriatric laryngeal muscle tissues at 12 weeks postinjection was evaluated and compared by histology, immunofluorescence staining, and functionality analysis. Results Total myofiber cross-sectional area and myofiber number/density, evaluated by detection of myosin heavy chain with antibodies against laminin and fast myosin heavy chain, were significantly higher in the SP group than in the other groups. The lamina propria of the larynx was evaluated by alcian blue staining, which showed that the HA was increased significantly in the SP group compared to the other groups. In functional analysis, the glottal gap area was significantly reduced in the SP group compared to the other groups. The phase difference in the vocal fold during vibration was also smaller in the SP group than in the other groups, but the difference did not reach statistical significance. Conclusion Injection of hASC spheroids with hyaluronic acid-based hydrogel improves the morphological and functional characteristics of geriatric larynx. Graphical abstract