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Background and Objectives: The purpose of this study was to investigate the prevalence of incidental paranasal sinus (PNS) opacification in nasal septal deviation (NSD) using computed tomography (CT) and to identify contributing factors. Subjects and Method: We analyzed 216 patients who underwent septoplasty for the correction of NSD and who underwent preoperative PNS CT. We assessed the prevalence of incidental PNS opacification in these patients and determined the type of NSD according to Mladina classification. We also evaluated whether the direction of NSD affected the presence of PNS opacification on CT, and whether the presence of PNS opacification was associated with other rhinologic symptoms. Results: Of 216 patients with NSD, 86 showed opacified PNS on CT. According to Mladina classification, NSD patients were classified as type I (24.1%), type II (36.1%), type III (20.8%), type IV (5.6%), type V (9.7%), type VI (2.3%), or type VII (1.4%). Patients with type II NSD showed a significantly higher incidence of PNS opacification compared with other types of NSD (p=0.001). However, the direction of NSD did not significantly influence the presence of incidental PNS opacification. Furthermore, regardless of the presence of PNS opacification, there was no significant difference in rhinologic symptoms such as olfactory dysfunction, among others. Conclusion: We found that incidental PNS opacification on CT was common in NSD patients, especially in patients with type II NSD. Thus, we suggest that CT evaluation of patients with NSD may be helpful for assessing comorbid PNS pathologies as well as objectively identifying nasal septal deformities. [ABSTRACT FROM AUTHOR]

Otorhinolaryngologic symptoms such as cough, rhinorrhea, anosmia, ageusia, and fever can precede development of COVID-19. Otolaryngologists are vulnerable to potential COVID-19 infection because early cases of COVID-19 have been asymptomatic or show mild manifestations. Otolaryngologists should wear adequate personal protective equipment (PPE) according as location or situation. PPE includes medical masks, goggles, and fluid-resistant gown and gloves. Authors provide clinical recommendations based on PPE for otorhinolaryngologists during the COVID-19 pandemic. In addition, we reviewed the literature related to clinical guidelines of foreign otorhinolaryngology societies with regard to COVID-19. [ABSTRACT FROM AUTHOR]

Actinomycosis of paranasal sinus is a very rare disease that is caused by infection of Actinomyces species that were present in oral or nasal flora due to trauma or dental treatment. Actinomycosis shows a local calcified lesion associated with soft tissue density on computed tomography, which is similar to fungal sinusitis. Actinomycosis associated with fungal ball due to Aspergillus affecting sinus ventilation has been rarely reported. We experienced two cases of actinomycosis associated with fungal ball and successfully treated with endoscopic sinus surgery and oral antibiotics for 3 months without recurrence. [ABSTRACT FROM AUTHOR]

This paper investigates pulse modulator bias circuit design for the drain of solid-state power amplifier with low peak charging current of capacitor banks. By using an inductor between a voltage regulator and the capacitor banks in the pulse modulator bias circuit, the charging time is delayed and current peak is reduced. The current charging characteristics corresponding to the inductance and DC resistance of the inductor are analyzed based on the damping time constant and oscillation frequency. Bounds of damping time constant and oscillation frequency are set for the capacitor banks to be charged by specified time periods for a maximum pulse repetition frequency of 2,600 Hz. Simulation results show that the current peak is significantly reduced by the inductor, and the current charging characteristics are similar to the analysis. The ratio of current peak and mean excluding stand-by current of a prototype without inductor is 10.0 A/A, while that of a prototype with inductors is enhanced to 2.3 A/A with an appropriate charging delay. [ABSTRACT FROM AUTHOR]

The power circuit design of an on-board S-band transmitter for KSLV-II with derating(operation of a component at less than its maximum rated specification to enhance reliability) is investigated. The power circuit of the transmitter consists of linear voltage regulators, DC/DC converters for regulating the DC supply, and diodes for reverse voltage protection. After analyzing the load current of the components, derating requirements are explored. Furthermore, power dissipation and junction temperature rise are considered with respect to the load current. The analysis is compared to the results from an engineering model of the transmitter. The temperature of the components is derated by >40℃ in an environment where the ambient temperature is +60℃, which is the acceptance test specification of high temperature. [ABSTRACT FROM AUTHOR]

Suicide is the fifth-leading cause of death in Korea, accounting for 4.4% of all deaths. Therefore, suicide is a serious medical problem, as well as a social problem. In this paper, we provide a social psychiatric perspective on suicide and recommend suicide prevention strategies based on programs with roots in the Gwangju mental health pilot project and an analysis of suicide patterns in Seoul. First, early intervention and active case management are mandatory to prevent suicide among individuals with mental illnesses such as depression, schizophrenia, and alcohol use disorder. To this end, mental health and welfare centers, addiction management centers, suicide prevention centers, and care program after a suicide attempt in the emergency department of general hospitals should collaborate via a multidisciplinary approach. Second, crisis intervention should be provided in collaboration with the police, government officials, and mental health agencies to people who are at immediate risk of suicide. Additionally, case management services should be expanded for individuals who are treated at hospitals for psychiatric illness. Third, social welfare services should be offered to low-income individuals at risk of suicide. Fourth, the mass media should restrict reporting about suicide and follow the relevant reporting guidelines. Finally, access to methods of committing suicide, such as charcoal for burning and agrichemical poisoning, should be regulated by the government. Proactive psychosocial strategies implemented with government support will prevent suicide-related deaths and decrease the suicide rate in Korea. [ABSTRACT FROM AUTHOR]

Background and Objectives: The skin prick test is a widely used test that uses three methods (allergen/histamine ratio method, erythema size method, and wheal size method) to interpret the results. However, there has been no comparison of these methods. The aim of this study is to compare the three different interpretation methods and define the relationship among them. Subjects and Method: A total of 139 patients who visited our allergy clinic complaining of nasal symptoms were enrolled. Three interpretation methods were used for defining positivity in the skin prick test, and their results were compared. The validity of each interpretation method was evaluated by total nasal symptom score. Results: Positivity in the skin prick test was reported in 48.2% of patients according to the allergen/histamine ratio method and in 64.0% of patients according to the wheal size method and erythema size method. The proportion of subjects who showed a negative result with the allergen/histamine ratio method but positive results with the wheal size method or erythema size method was 15.8%. This group had a significantly higher total nasal symptom score, especially rhinorrhea and nasal obstruction, than subjects who showed negative results on all three methods. Conclusion: When diagnosing allergic rhinitis patients using the skin prick test, the wheal size method and erythema size method should be considered rather than the allergen/histamine ratio method. [ABSTRACT FROM AUTHOR]

Background and Objectives: Endoscopic sinus surgery (ESS) was introduced to Korea in the 1980s and has since developed rapidly. There have been many changes in ESS over this period. Thus, in this paper, we explore trends in the clinical characteristics of ESS. Subjects and Method: We retrospectively reviewed patients who underwent the ESS at 000 Hospital performed by a single surgeon at a 10-year interval. By comparing 106 patients who underwent ESS in 2003 and 108 patients who underwent ESS in 2013, we investigated changes in ESS in terms of the target group of surgical indications, CT scores, range of operation and complications. Results: With regard to surgical indications, the proportion of patients who underwent surgery due to nasal polyps in 2013 (32.4%) was lower than in 2003 (59.4%), while the proportion of patients undergoing fungal sinusitis surgery in 2013 (13.9%) was higher than in 2003 (0.0%). In terms of preoperative CT evaluation, Lund-Mackay scores for the maxillary sinus, ethmoid sinus, and ostiomeatal unit were lower in 2013 than in 2003. The proportion of ESS performed only in the maxillary sinus in 2013 (20.0%) was higher than in 2003 (10.0%). Conclusion: According to this study, the range and extent of sinusitis was favorable in 2013 compared to in 2003. The group of patients requiring treatment for only maxillary sinus disease accounted for a larger proportion of patients in 2013 than in 2003. [ABSTRACT FROM AUTHOR]

Gout is characterized by recurrent attacks of arthralgia, and deposition of monosodium urate crystals in and around the joints of the extremities and soft tissues. Monosodium urate crystals are observed most frequently at the 1st metatarsophalangeal joint and usually presented in the ankle and wrist joint. However, no case of an intratendinous tophus in the patellar tendon has been reported in Korean literature. In this report, we found monosodium urate crystals in the patellar tendon on magnetic resonance imaging images and intratendinous tophus were visible to the naked eye by excision. We reported on the case of a patient who experienced an unusual intratendinous tophus in the patellar tendon. [ABSTRACT FROM AUTHOR]

Background: Random positioning machine (RPM) is a very effective device that can be used for space experiments on Earth. RPM had been constructed and verified for its ability to simulate microgravity conditions. This study was done to construct the RPM and to evaluate the growth pattern of Brasica on RPM. Methods: 2d clinostat was constructed and Arabidopsises were grown on it for 2 weeks. The experiment group on 2d clinostat was compared with the control group on Earth. RPM has been designed, constructed and checked for its ability to simulate microgravity conditions in the Seoul National University College of Medicine. Brasicas were grown for 72 hours both on RPM and on Earth and their growth patterns were compared. Results: RPM had operated in normal conditions without any significant failures. To verify the microgravity conditions, the summation of gravity vectors on the sample stage were depicted on a graph and also calculated by time. Each point of gravity vectors became an entire globe shape and the cumulated summation of gravity vectors decreased below 10-3 g. Conclusion: RPM was successfully constructed in Korea and automorphogenesis of Brasica was observed during their growth on RPM like space. Diverse experiments with plants and animal cells will be possible in the future on RPM. [ABSTRACT FROM AUTHOR]

In this paper, we propose a compact antenna hat to perform RF compatibility testing efficiently between the launch vehicle and ground stations. The proposed structure implements a small size and low loss using the conductive shield instead of the conventional RF absorber. The S-band antenna hat, which is fabricated for an inverted-F onboard antenna with the size of 74 mm×13 mm×16 mm, has the small enclosure of 88 mm×35 mm×44 mm, the return loss of 25.6 dB, the insertion loss of 0.26 dB, and the leakage loss of 49.4 dB at the center frequency of 2.25 GHz. The simulated and measured results show a good agreement. [ABSTRACT FROM AUTHOR]