• Ocean and Polar Research
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• v.38 no.4
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• pp.339-345
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• 2016

Stable water vapor isotopes have been utilized as a tracer for studying atmospheric global circulations, climate change and paleoclimate with ice cores. Recently, since laser spectroscopy has been available, water vapor isotopes can be measured more precisely and continuously. Studies of water vapor isotopes have been conducted over the world, but it is the early stage in south Korea. For vapor isotopes study, a cryogenic sampling device for water vapor isotopes has been developed. The cryogenic sampling device consists of the dewar bottle, filled with extremely low temperature material and impinger connected with a vacuum pump. Impinger stays put in the dewar bottle to change the water vapor which passes through the inside of impinger into the solid phase as ice. The fact that water vapor has not sampled completely leads to isotopic fractionation in the impinger. To minimize the isotopic fractionation during sampling water vapor, we have tested the method using a serial connection with two sets of impinger device in the laboratory. We trapped 98.02% of water vapor in the first trap and the isotopic difference of the trapped water vapor between two impinger were about 20‰ and 6‰ for hydrogen and oxygen, respectively. Considering the amount of water vapor trapped in each impinger, the isotopic differences for hydrogen and oxygen were 0.33‰ and 0.06‰, respectively, which is significantly smaller than the precision of isotopic measurements. This work can conclude that there is no significant fractionation during water vapor trapping.

• Journal of the Korean institute of surface engineering
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• v.56 no.3
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• pp.208-218
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• 2023

Photocatalysts are advanced materials which accelerate the photoreaction by providing ordinary reactions with other pathways. The catalysts have various advantages, such as low-cost, low operating temperature and pressure, and long-term use. They are applied to environmental and energy field, including the air and water purification, water splitting for hydrogen production, sterilization and self-cleaning surfaces. However, commercial photocatalysts only absorb ultraviolet light between 100 and 400 nm of wavelength which comprises only 5% in sunlight due to the wide band gap. In addition, rapid recombination of electron-hole pairs reduces the photocatalytic performance. Recently, studies on blackening photocatalysts by laser, thermal, and plasma treatments have been conducted to enhance the absorption of visible light and photocatalytic activity. The disordered structures could yield mid-gap states and vacancies could cause charge carrier trapping. Herein, liquid phase plasma (LPP) is adopted to synthesize Ag-doped black ZnO for the utilization of visible-light. The physical and chemical characteristics of the synthesized photocatalysts are analyzed by SEM/EDS, XRD, XPS and the optical properties of them are investigated using UV/Vis DRS and PL analyses. Lastly, the photocatalytic activity was evaluated using methylene blue as a pollutant.

• Tuberculosis and Respiratory Diseases
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• v.64 no.5
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• pp.356-361
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• 2008

Background: We wanted to examine the clinical characteristics of adult patients with tracheobronchial foreign bodies (FBs) according to the risk of aspiration and the outcomes of intervention with using a fiberoptic bronchoscope. Methods: From December 1994 through December 2004 at Kyung Hee Medical Center, we retrospectively analyzed the medical records of 29 adult patients with FBs that were identified by using a fiberoptic bronchoscope. Results: 14 patients were not at risk of aspiration, whereas 15 had cerebrovascular diseases and they were at a high risk of aspiration. No history suggestive of FB aspiration was noted in 7 (24.1%) patients. Respiratory symptom(s) were noted in 22 patients, and these symptoms were cough (62.0%), dyspnea (44.8%), fever (20.7%), wheezing (13.8%), chest pain (10.3%) and hemoptysis (0.4%). Only 60% of those patients at a high risk of aspiration had symptom(s) (92.8% of those patients without a risk of aspiration had symptoms, p=0.005). Those patients at risk for aspiration had a longer duration of symptoms (median: 4 days vs. 2 days for those patients not at risk for aspiration, p=0.007) before diagnosis. Acute respiratory symptom(s) within 3 days after aspiration were more frequent in the patients without a risk of aspiration (9 vs. 4, respectively p=0.048). Chest x-ray revealed radiological abnormalities in 23 patients, and these were opacities suspicious of FB (n=11), pneumonia (n=8), air trapping (n=5) and atelectasis (n=3). There were no differences in radiological findings according to the risk of aspiration. FB aspiration developed most commonly during medical procedures (57.1% for the patients at risk) and during eating (35.7% for the patients without risk). The most common FB materials were teeth (n = 11). Alligator jaw biopsy forceps (n = 23) was the most commonly used equipment. All of the FBs were removed without significant complications. Conclusion: This study underlines that a tracheobronchial FB in the patients who are at a high risk of aspiration are more likely to overlooked because of the more gradual onset of symptoms and the symptoms develop iatrogenically in many cases.

• The Korean Journal of Physiology
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• v.9 no.2
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• pp.7-15
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• 1975

The maximum breathing capacity (MBC) and the maximum mid-expiratory flow rate (MMF) are widely used in evaluation of the ventilatory function, among various parameters of pulmonary function. The MBC volume is the amount of gas which can be exchanged per unit time during maximal voluntary hyperventilation. Performance of this test, unlike that of single breath maneuvers, is affected by the integrity of the respiratory bellows as a whole including such factors are respiratory muscle blood supply, fatigue, and progressive trapping of air. Because of this, the MBC and its relation to ventilatory requirement correlates more closely with subjective dyspnea than does any other test. The MMF is the average flow rate during expiration of the middle 50% of the vital capacity. The MMF is a measurement of a fast vital capacity related to the time required for the maneuver and the MMF relates much better to other dynamic tests of ventilatory function and to dyspnea than total vital capacity, because the MMF reflects the effective volume, or gas per unit of time. Therefore, it is important to have a prediction formula with one can compute the normal value for the subject and the compare with the measured value. However, the formulas for prediction of both MBC and MMF of the Korean children and adolescents are not yet available in the present. Hence, present investigation was attempt to derive the formulas for prediction of both MBC and MMF of the Korean children and adolescents. MBC and MMF were measured in 1,037 healthy Korean children and adolescents (1,035 male and 1,002 female) whose ages ranged from 8 to 18 years. A spirometer (9L, Collins) was used for the measurement of MBC and MMF. Both MBC and MMF were measured 3times in a standing position and the highest values were used. For measurement, the $CO_2$ absorber and sadd valve were removed from the spirometer in order to reduce the resistance in the breathing circuit and the subject was asked to breathe as fast and deeply as possible for 12 seconds in MBC and to exhale completely as fast as possible after maximum inspiration for MMF. During the measurement, investigator stood by the subject to give a constant encouragement. All the measured values were subsequently converted to values at BTPS. The formulas for MBC and MMF were derived by a manner similar to those for Baldwin et al (1949) and Im (1965) as function of age and BSA or age and height. The prediction formulas for MBC (L/min, BTPS) and MMF (L/min, BTPS) of the Korean children and adolescents as derived in this investigation are as follows: For male, MBC=[41.70+{$2.69{\times}Age(years)$}]${\times}BSA$ $(m^{2})$ MBC=[0.083+{$0.045{\times}Age(years)$}]${\times}Ht$ (cm) For female, MBC=[45.53+{$1.55{\times}Age(years)$}]${\times}BSA$ $(m^2)$ MBC=[0.189+{$0.029{\times}Age(years)$}]${\times}Ht$ (cm) For male, MMF= [0.544+{$0.066{\times}Age(years)$}]${\times}Ht$ (cm) For female, MMF=[0.416+{$0.064{\times}Age(years)$}]${\times}Ht$ (cm)

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1148-1152
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• 2008

Molten carbonate oxidation (MCO) is one of the promising alternative technologies for the treatment of the chlorinated organic compounds because it is capable of trapping chlorine during a destruction of them. In this study, destructions of chlorinated organic compounds ($C_6H_5Cl$, $C_2HCl_3$ and $CCl_4$) and an insulated oil containing PCBs were performed by using the two stage molten carbonate oxidation system. MCO reactor temperature largely affected the destruction of the chlorinated organic compounds. Destruction of the chlorinated organics very efficient in the primary MCO reactor however a significant amount of CO was emitted from the MCO system. This CO emission was gradually decreased by an increase in the primary reactor temperature and oxidizing air feed rate. The HCl emission from the MCO system was below 7 ppm regardless of tested conditions. The chlorine collection efficiencies were in the range of 99.95-99.99%. The destruction of PCBs in the insulated oil was efficient at a temperature above $900^{\circ}C$ and overall destruction efficiency of them was determined as over 99.9999%.

• Tuberculosis and Respiratory Diseases
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• v.58 no.6
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• pp.600-606
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• 2005

Background : The development of bronchoscopic equipment along with the precision of radiographic techniques had reduced the mortality rate of patients with tracheobronchial foreign bodies but has been no change in the incidence of tracheobronchial foreign bodies since their introduction. The aim of this study was to assess the clinical characteristics of a tracheobronchial foreign body aspiration and to evaluate the efficacy of the treatment modality in children and adults. Methods : This is a retrospective review of 64 patients who underwent bronchoscopic procedures for the treatment of aspirated foreign bodies from December 1994 through March 2004 at the Chonnam national university hospital. Results : There were 47 males and 17 females, aged from 1 month to 78 years. Most of the patients had no underlying illness except for one patient with a cerebrovascular accident that contributed to the foreign body aspiration. The most common symptom was cough, which was noted in 54 patients (84.3%). The other presenting symptoms were dyspnea (48.8%), fever (20.3%), sputum (14%), vomiting (7.8%), and chest pain (4.6%). Those whose tracheobronchial foreign bodies were diagnosed more than 2 days after the aspiration (21 patients) were more likely to have pneumonia than those whose foreign bodies were diagnosed within 2 days (p = 0.009). Foreign bodies were visualized in the plain chest radiographs in 12 cases (18.8%), while others showed air trapping (21, 32.8%), pneumonia (15, 23.4%), atelectasis (7, 10.9%), and normal findings (9, 14.1%). The foreign bodies were more frequently found in the right bronchial tree (36) compared with the left bronchial tree (22, p = 0.04). In order to remove the foreign bodies, twenty (31.2%) cases were removed using flexible bronchoscopy, while 42 (65.6%) and 2 (3.2%) cases required rigid bronchoscopy and surgery, respectively. Conclusions : Tracheobronchial Foreign body aspiration had a bimodal age distribution in the infancy and old age around 60 years. They were found more frequently in the right bronchial tree. In addition, patients whose foreign bodies were diagnosed more than 2 days after the aspiration were more likely have a infection. Rigid bronchoscopy is the procedure of choice for uncooperative children and for those with foreign bodies lodged deeply in the small bronchial tree.

• Journal of Wetlands Research
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• v.20 no.1
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• pp.63-71
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• 2018

The particle filtration mechanisms in an infiltration trench should be varying due to the different hydraulic conditions during stormwater runoff. The understanding of these variations associated with different filtration mechanisms and their effect on the particle removal efficiency is of vital importance. Therefore, a LID (Low Impact Development) system comprising of an infiltration trench packed with gravel and woodchip was investigated during the monitoring of several independent rainfall events. A typical rainfall event was divided into separate regimes and their corresponding flow conditions as well as filtration mechanisms in the trench were analyzed. According to hydraulic conditions, it was found out that filtration changes between vertical and horizontal flows as well as between unsaturated, saturated, and partially-saturated flows. Particle separation efficiency was high (55-76%) and was mainly governed by physical straining during the unsaturated period. It was then enhanced by diffusion during the saturated period (75-95%). When the trench became partially saturated at the end of the rainfall event, the efficiency decreased which was believed to be due to the existence of a negatively charged air-water interface which limited the removal to positively charged particles.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.15 no.1
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• pp.60-64
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• 2019

Swyer-James syndrome (SJS), also known as Swyer-James-MacLeod syndrome and unilateral hyperlucent lung syndrome, is rare acquired pulmonary disorder develops secondary to infectious etiologies in early childhood. Viral respiratory infection such as adenoviruses or Mycoplasma pneumoniae in infancy or early childhood rarely cause Swyer-James syndrome. It is generally characterized on radiographs by a unilateral small lung with hyperlucency and air trapping on expiration. In many cases unaffected lung tissue functions normally, compensating for affected lung portion. Preoperative assessment is needed to determinate individual's pulmonary function. A 4-year-old boy with Swyer-James syndrome visited Seoul National University Dental Hospital Department of pediatric dentistry for caries treatment. Clinical and radiographic examinations revealed multiple carious lesions on deciduous teeth. Considering patient's underling disease, age, and level of cooperation, dental treatment under general anesthesia was scheduled. Dental treatment was done with composite resin and stainless-steel crown. Since ventilation of Swyer-James syndrome patients was diminished because of airway obstruction, close monitoring of ventilation is necessary during dental treatment. Considering pulmonary pathology, general anesthesia rather than sedation is recommended when special behavior management is required for dental treatment. Swyer-James syndrome patients can tolerate general anesthesia and surgery well, according to several reports.

• Korean Journal of Radiology
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• v.20 no.4
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• pp.683-692
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• 2019

Objective: We aimed to evaluate correlations between computed tomography (CT) parameters and pulmonary function test (PFT) parameters according to disease severity in patients with chronic obstructive pulmonary disease (COPD), and to determine whether CT parameters can be used to predict PFT indices. Materials and Methods: A total of 370 patients with COPD were grouped based on disease severity according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) I-IV criteria. Emphysema index (EI), air-trapping index, and airway parameters such as the square root of wall area of a hypothetical airway with an internal perimeter of 10 mm (Pi10) were measured using automatic segmentation software. Clinical characteristics including PFT results and quantitative CT parameters according to GOLD criteria were compared using ANOVA. The correlations between CT parameters and PFT indices, including the ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) and FEV₁, were assessed. To evaluate whether CT parameters can be used to predict PFT indices, multiple linear regression analyses were performed for all patients, Group 1 (GOLD I and II), and Group 2 (GOLD III and IV). Results: Pulmonary function deteriorated with increase in disease severity according to the GOLD criteria (p < 0.001). Parenchymal attenuation parameters were significantly worse in patients with higher GOLD stages (P < 0.001), and Pi10 was highest for patients with GOLD III (4.41 ± 0.94 mm). Airway parameters were nonlinearly correlated with PFT results, and Pi10 demonstrated mild correlation with FEV1/FVC in patients with GOLD II and III (r = 0.16, p = 0.06 and r = 0.21, p = 0.04, respectively). Parenchymal attenuation parameters, airway parameters, EI, and Pi10 were identified as predictors of FEV₁/FVC for the entire study sample and for Group 1 (R² = 0.38 and 0.22, respectively; p < 0.001). However, only parenchymal attenuation parameter, EI, was identified as a predictor of FEV₁/FVC for Group 2 (R² = 0.37, p < 0.001). Similar results were obtained for FEV₁. Conclusion: Airway and parenchymal attenuation parameters are independent predictors of pulmonary function in patients with mild COPD, whereas parenchymal attenuation parameters are dominant independent predictors of pulmonary function in patients with severe COPD.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.343-349
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• 2012

Exposure and risk assessments were conducted to evaluate the relative safety of mixing/loading work of indoxacarb between wettable powder (WP) and water dispersible granule (WG). Hand exposure was monitored using cotton gloves while inhalation exposure was measured using personal air monitor. Method validation for the exposure monitoring was established successfully through several experiments. Limit of determination and limit of quantitation were 0.25 and 1 ng, respectively. $R^2$ of calibration curve linearity was more than 0.9999 and reproducibility was 0.7-6. Recovery of indoxacarb from gloves, solid sorbent and glass fiber filter at three different levels was 81.5-108.8%. Trapping efficiency and breakthrough tests gave 981.5-108.8% of recovery. During mixing/loading procedure, hand exposure amount (75 percentile of 30 repetitions) for indoxacarb WP was 6 folds (459.8 mg/kg a.i) than that of WG (81.4 mg/kg a.i). This result indicates that WG has less drift than WP thanks to its granular type of formulation. Inhalation amount was $10^{-8}-10^{-7}%$ of spray mixture prepared and $10^{-4}-10^{-3}%$ of hand exposure. In inhalation case, no significant differences were observed between two formulations. Margin of safety was calculated for risk assessment using male Korean average body weight and acceptable operator exposure level as the important exposure factors. Mixing/loading procedures for both of the formulations were considered to be of least risk because calculated MOS values were more than 1.