• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2459-2465
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• 2012

Background: Numbers of epidemiological studies assessing residential radon exposure and risk of lung cancer have yielded inconsistent results. Methods: We therefore performed a meta-analysis of relevant published case-control studies searched in the PubMed database through July 2011 to examine the association. The combined odds ratio (OR) were calculated using fixed- or random-effects models. Subgroup and dose-response analyses were also performed. Results: We identified 22 case-control studies of residential radon and lung cancer risk involving 13,380 cases and 21,102 controls. The combined OR of lung cancer for the highest with the lowest exposure was 1.29 (95% CI 1.10-1.51). Dose-response analysis showed that every 100 Bq/$m^3$ increment in residential radon exposure was associated with a significant 7% increase in lung cancer risk. Subgroup analysis displayed a more pronounced association in the studies conducted in Europe. Studies restricted to female or non-smokers demonstrated weakened associations between exposure and lung cancer. Conclusions: This meta-analysis provides new evidence supporting the conclusion that residential exposure to radon can significantly increase the risk of lung cancer in a dose-response manner.

• Journal of The Korean Society of Clinical Toxicology
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• v.18 no.1
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• pp.34-41
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• 2020

Purpose: This study evaluated aggressive hyperbaric oxygen therapy (HBOT) by understanding various exposure routes of acute carbon monoxide (CO) poisoning, the risk factors causing acute cardiovascular, and neurological toxicity caused by poisoning. Methods: A retrospective study was conducted based on the medical records of 417 acute CO poisoning patients who visited the emergency care unit from March 2017 to August 2019. The exposure routes, HBOT performance, age, sex, medical history (hypertension, diabetes mellitus, ischemic heart disease, heart failure), intentionality, loss of consciousness (LOC), intake with alcohol or sedatives, and initial test results (carboxyhemoglobin (COHb), troponin-I, electrocardiography, echocardiography, brain MRI) were examined. Comparative analysis of the clinical information was conducted between the groups that showed acute cardiovascular toxicity and neurological toxicity, and groups that did not. Results: Among 417 patients diagnosed with acute CO poisoning, 201 cases (48.2%) were intentional, and charcoal briquette was the most common route (169 patients (40.5%)). Two hundred sixteen cases (51.8%) were accidental, and fire was the most common route (135 patients (32.4%)). The exposure route was more diverse with accidental poisoning. Three hundred ninety-nine patients were studied for acute cardiovascular toxicity, and 62 patients (15.5%) were confirmed to be positive. The result was statistically significant in intentionality, LOC, combined sedatives, initial COHb, HTN, and IHD. One hundred two patients were studied for acute neurological toxicity, which was observed in 26 patients (25.5%). The result was statistically significant in age and LOC. Conclusion: Active HBOT should be performed to minimize damage to the major organs by identifying the various exposure routes of CO poisoning, risk factors for acute cardiovascular toxicity (intentionality, LOC, combined sedatives, initial COHb, HTN, IHD), and the risk factors for acute neurological toxicity (age, LOC).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.261-266
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• 1989

This study was undertaken to compare those 4 most commonly used incisions for exposure of fractures of the infraorbital rim and the orbital floor. The patient's age ranged from 19 to 67 years, the majority being in the 2nd decade. There were 17males and 1 female. Three orbital rim, 5 lower eyelid, 7 subciliary and 3 combined conjunctival-lateral canthotomy incisions were reviewed. Following points were the summury of author's experience. 1. The average scar following any of four incisions is barely noticeable. 2. Adequate fracture exposure was achieved with lower eyelid, orbital rim, subciliary and combined conjunctival-lateral canthotomy incisions. 3. One transient ectropion following subciliary incision occurred in 29-years old man with prolonged postoperative eyelid edema.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1416-1425
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• 2002

In this study, the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated by the use of an accelerated aging test. Environmental factors such as temperature, moisture. and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile. bending, and shear specimens those are transverse to the fiber direction, and bending specimens those are parallel to the tiber direction - were used to investigate the effects of environmental factors on mechanical properties of the composites. Also, glass transition temperature, storage shear modulus, loss shear modulus, and tan ${\delta}$ were measured as a function of exposure times through a dynamic mechanical analyzer. In addition. a suitable testing method for determining the effect of environmental factors on mechanical properties is suggested by comparing the results from using two different types of strain measuring sensors. Finally, composite surfaces exposed to environmental factors were examined using a scanning electron microscope.

• 월간산업보건
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• s.350
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• pp.47-59
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• 2017

• Proceedings of the Korean Society of Life Science Conference
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• 2004.10a
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• pp.33-34
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• 2004

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.11-18
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• 2016

In this paper, we propose a gas classification method using combined features for an electronic nose system that performs well even when some loss occurs in measuring data samples. We first divide the entire measurement for a data sample into three local sections, which are the stabilization, exposure, and purge; local features are then extracted from each section. Based on the discrimination analysis, measurements of the discriminative information amounts are taken. Subsequently, the local features that have a large amount of discriminative information are chosen to compose the combined features together with the global features that extracted from the entire measurement section of the data sample. The experimental results show that the combined features by the proposed method gives better classification performance for a variety of volatile organic compound data than the other feature types, especially when there is data loss.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.364-366
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• 2004

WDR(Wide Dynamic Range) camera has been recently introduced to provide good detailed information for the extremely dark or white area. The double shuttering camera acquires two pictures with different exposure time for the same scenes so that each image has its unique information as for the bright/dark area. Those images are combined internally to produce an image with enough details. This paper proposes a NN based method to control the exposure time of the WDR camera. Our goal is to develop a method to automatically control the exposure time like human decision. A neural model is trained to determine to increase/decrease shutter time for the given situation. The ability to adapt to unknown situation is shown for the sample cases.

• Journal of the Korean institute of surface engineering
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• v.35 no.5
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• pp.312-318
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• 2002

A study on the change of mechanical properties and oxidation behavior of Zircaloy-4 fuel cladding after exposing at 90$0^{\circ}C$ and $1000^{\circ}C$ for various periods of exposure time under the steam atmosphere was carried out. The growth of the $ZrO_2$ layer combined with an oxygen-rich-phase layer into the Zircaloy tube material can be described by an expression, E = 1.1√Dt + $2 $\times$ 10^{-4}$ . The tensile strength of Zircaloy tubes increased for a short period of exposure time and decreased rapidly with further exposure while the hoop strength was not decreased greatly. In the meantime, the axial and circumferential elongations of oxidized Zircaloy tubes were decreased drastically with increasing exposure time as a result of embrittlement phenomena.

• Journal of Radiation Protection and Research
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• v.42 no.3
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• pp.146-153
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• 2017

Background: Acute radiation syndrome (ARS) primarily refers to damage to the hematopoietic system, myeloid system, and gastrointestinal (GI) system caused by radiation exposure. Such damage progresses to become life-threatening. In particular, as the syndrome develops very rapidly-within several hours from radiation exposure-prompt and accurate diagnosis and treatment are needed, as is further research into appropriate diagnostic and treatment modalities. Materials and Methods: Minipigs, which display human-like properties, underwent whole-body irradiation at 2 or 4 Gy (doses causing hematopoietic ARS) or at higher doses of 7 or 12 Gy. Changes in the blood cells and clinical symptoms were analyzed and we performed a necropsy when the animals succumbed to ARS. Results and Discussion: The minipig irradiated with 2 Gy showed a decrease in white blood cells, including neutrophils, lymphocytes, and platelets in the early stages. However, the blood cell counts gradually increased and returned to normal values. The minipig irradiated with 4 Gy succumbed due to hematopoietic ARS. In contrast, the minipigs irradiated with 7 or 12 Gy exhibited clinical symptoms of combined GI damage and hematopoietic syndrome. Moreover, a characteristic pattern of platelet changes was observed in the 7 and 12 Gy irradiated minipigs. Conclusion: The changes in the platelet count caused by radiation exposure observed in minipigs, which are hematologically and pathohistologically similar to humans, suggest that they can be used as a novel diagnostic criterion.