• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.480-490
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• 2018

Objective: This study aimed to report the level of extremely low frequency-magnetic field (ELF-MF) emitted by portable hand-held fans (HHF) and to discuss the methodologies for determining the health risk of ELF-MF for HHF products. Method: ELF-MF was monitored at eight locations by distances in the vicinity of HHFs. A total of 13 HHF brands on the market were randomly selected. A portable ELF-MF monitor MDEX II was used to measure the ELF-MF level in the range of 40-800 Hz with a resolution of $0.01{\mu}T$. This study also examined the frequency results of a total of 45 HHF products investigated by the Korean Ministry of Science and ICT (KMSICT). Results: ELF-MF higher than $0.3{\mu}T$ was found to be emitted at a distance of less than 20 cm from 12 HHF. ELF-MF emitted from four products was found to exceed the reference level ($83.3{\mu}T$ based on 60 Hz) recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). KMSIT reported that the principle frequency emitted from the HHFs ranged from 54 Hz to 284 kHz, without the level of LEF-MF. Unscientifically, the KMSICT used the reference level by ICNIRP as the chronic level and concluded that all HHFs are safe with a basis of 1.2-36.0% less than the reference level. Conclusion: The HHF emitted much higher levels of ELF-MF than $0.3-0.4{\mu}T$, which is regarded as the reference level for childhood leukemia. The risk of HHF should be examined in terms of whether they can be used by the general public, including children and pregnant woman.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.1-7
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• 2011

The objective of the present study is to identify the applicability of a low pressure fogging system for cooling commercial tomato greenhouse. In particular, the cooling system in this experiment utilizes low pressure spray nozzles which were developed in Korea recently. The experimental result that the temperature in fog-cooled greenhouse was lower than the non-cooled greenhouse showed the cooling effect by the low pressure fogging system. But because the relative humidity in fog-cooled greenhouse was comparatively low, the satisfactory cooling effect could be acquired by narrowing the space of fog nozzles and extending fogging time to supply more fog spray quantity. The variation of temperature distribution in fog-cooled greenhouse along timelag was insignificant during short time, but that was great during long period of day. This result showed the variation of temperature along timelag was slight by fog cooling but great by other factors like radiation, ventilation, air flow, etc. The advanced operation technology of fog system was required to reduce the variation of temperature along time lag. We plan to suggest the advanced installation and operation technology of low pressure fogging system for cooling commercial tomato greenhouse by further experiments in near future.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.6
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• pp.771-781
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• 2013

This study was performed to investigate the anti-photoaging effects of Persimmon leaf tea(PLT) in hairless mice(SKH-1) exposed to UVB irradiation. The animals were divided into non-treated group (normal, N) and UV-radiated groups. UV-radiated groups were divided into only UV-radiated group(control, C) and UV-radiated and PLT treated experimental groups[first extraction treated group(PLT-I), second extraction treated group(PLT-II), and third extraction treated group(PLT-III)]. Three PLT treated experimental groups of mice were treated with both oral administration(300 mg/Kg B.W./day) and topical application (100 ul of 2% conc./mouse/day) for 4 weeks. Anti-photoaging effects of Persimmon leaf were evaluated by anti oxidative reaction, stereomicroscopic and microscopic observations. The expression of photoaging skin related factors including mast cell tryptase, proliferating cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF) was examined by immunohistochemical staining. Treatment of PLT-I, -II, -III prevented the wrinkle formation as well as epidermal hyperplasia, inflammatory cells, disruption of collagen in photoaged skin induced by UVB radiation. It also reduced the PCNA and VEGF expression in the UVB irradiated dorsal skin. Furthermore, it significantly decreased the number of mast cells in the UVB irradiated dermis(p<0.05 and p<0.01). On the effects of oxidative stress and antioxidant function on the treatment with water extract from Persimmon leaf tea(PLT), the activity of superoxide dismutase(SOD) was significantly increased in PLT-III group(p<0.05), and catalase(CAT) was significantly increased in PLT-I and PLT-III groups(p<0.05), and PLT-II group(p<0.001). These extracts showed relatively antioxidant activity and protective effect on UVB-induced oxidative stress in hairless mice(SKH-1). Our results suggest that Persimmon leaf tea may serve as an useful radical scavenging antioxidant and anti-photoaging skin agents in the UVB irradiated skin.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.640-647
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• 2014

Infrared signature of aircraft exhaust plume is the critical factor for aircraft survivability. To improve the military aircraft survivability, the accurate prediction of infrared signature for the propulsion system is needed. The numerical analysis of thermal fluid field for nozzle inflow, free stream flow, and plume region is conducted by using the in-house code. Weighted Sum of Gray Gases Model based on Narrow Band with regrouping is adopted to calculate the spectral infrared signature emitted from aircraft exhaust plume. The accuracy and reliability of the developed code are validated in the one-dimensional band model. It is found that the infrared radiant intensity is relatively more strong in the plume through the analysis, the results show the different characteristic of the spectral infrared signature along the temperature, the partial pressure, and the species distribution. The continuous spectral radiant intensity is shown near the nozzle exit due to the emission from the nozzle wall.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.1005-1014
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• 2019

The purpose of this study is to evaluate the usefulness of coronary computed tomography angiography of coronary artery disease for the purpose fo health screening according to gender and age. In addition the association between hematological factors (Glucose, total cholesterol, visceral fat, body mass index, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL)) and coronary artery disease is investigated. A retrospective analysis of coronary computed tomography angiography with 299 subjects showed that the detection rate of coronary artery disease was higher in men over 50 years of age and it was statistically significant. In particular, the prevalence rate of men (37.9%) was about 2 times higher than that of women (17.0%). Glucose and HDL as hematological factors associated with coronary artery disease were statistically significant. The prevention and management of coronary artery disease seems to require the control of glucose and high density lipoprotein (HDL). Although it is not statistically significant with other hematological factors, the need for management of coronary artery disease was identified. the coronary computed tomography angiography of coronary artery has higher radiation doses than other CT scans. Therefore, for the purpose of screening, coronary computed tomography angiography should be considered in consideration of the sex and age of the examinee, and detection of coronary artery disease through other non-invasive tests should be prioritized over coronary computed tomography angiography.

• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.43-48
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• 2017

Chemotherapy, radiation therapy, and surgery are major methods to treat cancer. However, current cancer treatments report severe side effects and high recurrences. Recent studies about engineering nanoparticles as a drug carrier suggest possibilities in terms of specific targeting and spatiotemporal release of drugs. While many nanoparticles demonstrate lower toxicity and better targeting results than free drugs, they still need to improve their performance dramatically in terms of targeting accuracy, immune responses, and non-specific accumulation at organs. One possible way to overcome the challenges is to make precisely controlled nanoparticles with respect to size, shape, surface properties, and mechanical stiffness. Here, we demonstrate $500{\times}200nm$ discoidal polymeric nanoconstructs (DPNs) as a drug delivery carrier. DPNs were prepared by using a top-down fabrication method that we previously reported to control shape as well as size. Moreover, DPNs have multiple payloads, poly lactic-co-glycolic acid (PLGA), polyethylene glycol (PEG), lipid-Rhodamine B dye (RhB) and Salinomycin. In this study, we demonstrated a potential of DPNs as a drug carrier to treat cancer.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1316-1321
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• 2000

Objectives : The authors analyzed the surgical series of Cushing's disease to evaluate the proper treatment policy and to verify the possible prognostic factors. Material and Methods : Of 50 patients diagnosed as Cushing's disease and operated at Department of Neurosurgery of our institute between 1988 and 1999, 48 patients with available medical records were analyzed retrospectively. Mean follow-up period was 48 months(3 to 109 months). Preoperative diagnosis was made after evaluating the patients with multiple-stage endocrinological studies and 31 selective patients were evaluated with inferior petrosal sinus sampling(IPSS). Magnetic resonance imaging(MRI) and/or high resolution computerized tomography(CT) was done in all patients. A total of 51 transsphenoidal adenomectomy(TSA) were performed including 3 revision for initial surgical failure cases. Remission was decided on the basis of both endocrinological criteria and clinical status. Radiation and/or ketoconazole therapy were applied to failed cases. For the verification of prognostic factors, the authors evaluated the statistical significance of multiple variables over remission rate by chi-square test. Result : Sensitivity of IPSS for central localization was 93.5% which was better than that of MRI(87.5%). But for lateralization, it was 72.4% for IPSS versus MRI 90.5%. Success rate of TSA was 82%(42/51) and recurrence rate was 9%(4/48). When including adjuvant treatments for surgically failed cases, overall success rate was 89.6% and all of 3 reoperated cases(TSA) due to recurrence were successful. Significant complication occurred in 7.8%(4/51) after TSA including hypopituitarism, diabetes insipidus, and visual loss. Non-existence of tumor in MRI and prolonged symptom duration(>3 years) were significant prognostic factors. Conclusion : TSA can be considered as initial treatment for Cushing's disease. In surgically failed cases, multiple treatment modality may improve the overall outcome and repeated TSA for recurrent cases seem to provide similar success.

• Food Science and Preservation
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• v.19 no.1
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• pp.47-53
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• 2012

UV light irradiation is known to give beneficial effects on fresh produce preservation. A container system equipped with UV-LED was fabricated for storing cherry tomatoes under computer-controlled conditions of intermittent on-off cycles (1 hour on/1 hour off). Wavelength (365 and 405 nm) and physical location of the LED (2 and 5 cm above fruit) were studied as variables affecting the respiration, ethylene production and quality preservation of the fruits at 10 and $20^{\circ}C$. 365 nm wavelength gave much higher radiation intensity than 405 nm, and intensity on surface decreased in inverse proportion to square of distance from LED. When compared to non-irradiated control, UV-LED irradiation decreased the respiration by 5-10% at $10^{\circ}C$ while there was no obvious effect at $20^{\circ}C$. Ethylene production was reduced when the fruits were placed at 5 cm distance, while there was no significant difference from control at 2 cm location. The reduction of ethylene production at 5 cm was more pronounced at $20^{\circ}C$. UV-LED irradiation was shown to have delayed increase or lower concentration in carotenoids compared to control treatment. Any negative effect of UV-LED irradiation on ascorbic acid content and firmness was not observed.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.171-182
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• 1990

The purpose of this study was to investigate the effects of irradiation on the striated duct cells of the rat submandibular gland ductal tissues which control the characteristics of saliva. For this study, the experimental group was composed of 36 irradiated Sprague Dawley strain rats divided into 8 subgroups 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours after irradiation. 4 non-irradiated rats were used as the control group. The experimental animals were singly irradiated with a dose of 18Gy gamma ray to their head and neck region by the Co-6- teletherapy unit and sacrificed after each experimental duration. The specimens were examined with a light microscope with an H-E stain and with a trans- mission electron microscope. The results of this study were as follows. In the light micrograph, a severe atrophic change occurred in the striated duct cells at 2hours after irradiation and gradual recovery occurred from 6 hours after irradiation. 2. The nuclear chromosomes of the striated duct cells were changed granular at 2 hours after irradiation. Recovery was observed at 6 hours after irradiation. Nuclear bodies were also observed from 3 hours after irradiation. 3. The mitochondria of the striated duct cells had indistinct cristae at 2 hours after irradiation, and were degenerated or swollen at 3 hours after irradiation. They recovered, however, from 6 hours, with an increasing number at 48 hours and a regular arrangement was observed at 72 hours after irradiation. 4. The microvilli showed atrophic changes at 2 hours after irradiation and were almost lost at 3 hours after irradiation. They were observed again from 48 hours after irradiation. 5. The rough endoplasmic reticulum and golgi body were not apparent at 1 hour after irradiation and were dilated with degeneration 2 hours after, but intact rough endoplasmic reticulum were observed from 3 hours after irradiation and developed well at 24 hours after irradiation. By the result of this study, showing a mild change in the functional morphology of the salivary striated duct cells immediately following irradiation, it is considered that the many complications which occur after radiation therapy, will disappear in time with the histological and the functional recovery of the glandular tissues.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.489-494
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• 2013

Background: Lung cancer is one of the commonest and most lethal cancers throughout the world. The epidemiological and pathological profile varies among different ethnicities and geographical regions. At present adenocarcinoma is the commonest histological subtype of non-small cell lung cancer (NSCLC) in most of the Western and Asian countries. However, in India squamous cell carcinoma has been reported as the commonest histological type in most of the series. The aim of the study was to analyze the current clinico-pathological profile and survival of lung cancer at our centre. Materials and Methods: We analyzed 434 pathologically confirmed lung cancer cases registered at our centre over a period of three years. They were evaluated for their clinical and pathological profiles, treatment received and outcome. The available histology slides were reviewed by an independent reviewer. Results: Median age was 55 years with a male:female ratio of 4.6:1. Some 68% of patients were smokers. There were 85.3% NSCLC and 14.7% SCLC cases. Among NSCLCs, adenocarcinoma was the commonest histological subtype after the pathology review. Among NSCLC, 56.8% cases were of stage IV while among SCLC 71.8% cases had extensive stage disease. Some 29% of patients did not receive any anticancer treatment. The median overall and progression free survivals of the patients who received treatment were 12.8 and 7.8 months for NSCLC and 9.1 and 6.8 months for SCLC. Conclusions: This analysis suggests that adenocarcinoma may now be the commonest histological subtype also in India, provided a careful pathological review is done. Most of the patients present at advanced stage and outcome remains poor.