• Progress in Medical Physics
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• v.26 no.1
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• pp.28-35
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• 2015

In this study, we investigated the effects of an iterative reconstruction algorithm and an automatic exposure control (AEC) technique on image quality and radiation dose through phantom experiments with coronary computed tomography (CT) angiography protocols. We scanned the AAPM CT performance phantom using 320 multi-detector-row CT. At the tube voltages of 80, 100, and 120 kVp, the scanning was repeated with two settings of the AEC technique, i.e., with the target standard deviations (SD) values of 33 (the higher tube current) and 44 (the lower tube current). The scanned projection data were reconstructed also in two ways, with the filtered back projection (FBP) and with the iterative reconstruction technique (AIDR-3D). The image quality was evaluated quantitatively with the noise standard deviation, modulation transfer function, and the contrast to noise ratio (CNR). More specifically, we analyzed the influences of selection of a tube voltage and a reconstruction algorithm on tube current modulation and consequently on radiation dose. Reduction of image noise by the iterative reconstruction algorithm compared with the FBP was revealed eminently, especially with the lower tube current protocols, i.e., it was decreased by 46% and 38%, when the AEC was established with the lower dose (the target SD=44) and the higher dose (the target SD=33), respectively. As a side effect of iterative reconstruction, the spatial resolution was decreased by a degree that could not mar the remarkable gains in terms of noise reduction. Consequently, if coronary CT angiogprahy is scanned and reconstructed using both the automatic exposure control and iterative reconstruction techniques, it is anticipated that, in comparison with a conventional acquisition method, image noise can be reduced significantly with slight decrease in spatial resolution, implying clinical advantages of radiation dose reduction, still being faithful to the ALARA principle.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.237-246
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• 2015

Purpose: The present study was conducted to reveal the correlation of structural denaturation and decrease of enzyme activity when the antioxidative enzymes, superoxide dismutase (SOD) and catalase (CAT) were repeatedly exposed to UV-B, and further investigate whether the denaturation and inactivation of those enzymes can be effectively blocked by using UV-inhibitory RGP lens. Methods: Each enzyme solution was prepared from the standardized SOD and CAT, and repeatedly exposed to UV-B of 312 nm for 30 minutes, 1 hour and 2 hours a day over 1, 2, 3, 4 and 5 days. Structural denaturation of SOD and CAT induced by repeat UV-B irradiation was confirmed by the electrophoretic analysis, and their enzyme activity was determined by the colorimetric assay using the proper assay kit. At that time, the change in structure and activity of the antioxidant enzymes directly exposed to UV-B was compared to the case that UV-B was blocked by UV-inhibitory RGP lens. Results: SOD exposed repeatedly to UV-B showed the polymerization pattern in the electrophoretic analysis when it repeatedly exposed for 30 min a day, however, the change of its activity was less than 10%. On the other hand, CAT repeatedly exposed to UV-B reduced size and density of the electrophoretic band which indicated a structure denaturation, and its activity was significantly decreased. In the case that the repeat exposure time was longer, CAT activity was completely lost even though some enzyme band occurred in the electrphoretic analysis. In addition, the degeneration of CAT due to UV-B irradiation was inhibited to some extent by using RGP lens with a UV-B blocking of 63.7%, however, it was not completely inhibited. Conclusions: From these results, it was revealed that the structural denaturation of antioxidative enzymes was not perfectly correlated with the reduction in enzyme activity according to the type of enzyme. It is recommended to minimize the exposure time to UV when wearing contact lens, or wear the contact lenses having UV blocking rate of the FDA Class I blocker or the sunglasses having equivalent UV-blocking rate for reducing the damage of antioxidative enzymes induced by UV.

• Toxicological Research
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• v.18 no.1
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• pp.23-29
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• 2002

Disodium disulphite, the HPV chemical, was assigned to Korea in order to implement OECD SIDS program in 1999. It was produced about 3,200 ton/year in 1998. This report evaluates the toxic potency of disodium disulphite based on the environmental and mammalian effects as well as human exposure. Oral $LD_{50}$ in rats is 1,540 mg/kg b.w. and effects was observed to the stomach, liver and the GI track that was filled with blood. For repeated dose toxicity, the predominant effect was the induction of stomach lesion due to local irritation. The no observed adverse effect lever for local (stomach irritation) was about 217 mg/kg bw/day. There is no evidence that disodium disulphite is genotoxic in vivo. No reproductive or developmental toxicty of disodium disulphite was observed for the period up to 2 yr and over three generation. In humans, urticaria and asthma with itching, edema, rhinitis, and nasal congestion were reported. Disodium disulphite is unlikely to induce respiratory sensitization but may enhance symptom of asthma in sensitive individuals. This chemical would be mainly transported to water compartment when released to environmental compartments since it is highly water soluble (470 g/l at 20). Low K oc (2.447) indicates disodium disulphite is so mobile in soil that it may not stay in the terrestrial compartment. The chemical has been tested in a limited number of aquatic species. hem acute toxicity test to fish, 96 hr-$LC_{50}$ was > 100 mg/1. For algae, 72 hr-$XC_{50}$ was 48.1 mg/1. For daphnid, the acute toxicity value of 48 hr-$EC_{50}$ was 88.76 mg/1, and chronic value of 21day-NOEC was > 10 mg/1. Therefore, PNEC of 0.1 mg/l for the aquatic organism was obtained from the chronic value of daphnid using the assessment factor of 100. Based on these data the disodium disulphite was recommended as low priority for further post-SIDS work in OECD.

• Journal of Families and Better Life
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• v.30 no.6
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• pp.167-181
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• 2012

This study analyzed consumer's harsh complaining behaviors and firm's reactions toward consumers' harsh complaining behavior, and investigated the differences in the firms' reactions according to the characteristics of counselors and customer service centers. In addition, this study attempted to find a strategy and provide guidance regarding consumer's harsh complaining behaviors. The results of this study are discussed below. First, consumer's harsh complaining attitudes were expressed by crude language, violent language, threats, personal attacks, and claims of a high-ranking social position. Consumer's directive, complaining behaviors were repeated on the telephone, and threats of prosecution or disclosure to the public, exposure of habitual product returns, and requests for interviews with superiorsat the representative firm were made. Second, a firm typologies according to its reaction style toward a consumer's harsh complaining behaviors were as follows: Group 1, having a neutral attitude toward consumers and preparation thoroughly regarding their demands; Group 2, having a negative attitude toward consumers and some degree of preparation toward consumers' demands; and finally, Group 3, having a positive attitude toward consumers but offering insufficient reparation regarding consumers' demands. Third, female counselors, counselors having a certified counselor's license, and those much experience working in labor work were more likely to be in Group 3. Male counselors, part-time counselors, and those having experience of many years were more likely to be in Group 2. Group 1 were more likely to have large number of workers at customer service centers, male counselors, and to have large numbers of educational training programs related to the reactions of consumers in the form of dissatisfaction, complaints, how to offer compensation for injuries to consumers, and issues related to PL(product liability). In addition, Group 1 also had more firm level welfare policies related to hight stress levels of consumer counselors and extra types of support regarding harsh consumers. However, Group 2 members were more likely to provide excessive compensation and rewards to harsh consumers. Finally, to react to consumer's harsh complaint efficiently, it was suggested that firms should not treat consumers as harsh consumers, should react to consumers' complaints sincerely, and should take precautionary management efforts as regards consumer dissatisfaction based on better quality control of products. In addition, it was deemed necessary to formulate a management strategy to train competent consumer counselors with a high quality of counselor skill, having standardized and consistent reaction guidance toward consumer complaints and thorough knowledge of compensation rules for consumer injuries and subsequent guidance.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.914-921
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• 1997

Hereditary hemorrhagic telangiectasia(Osler-Rendu-Weber Syndrome) is characterized by telangiectasia of the skin and mucous membranes and intermittent bleeding from vascular abnormalities. About 20% of patients with this syndrome have pulmonary arteriovenous fistulas. Pulmonary arteriovenous fistula is uncommon malformation which has an abnormal connection between the pulmonary capillary bed, in which venous blood in the pulmonary artery is shunted through the fistula into the pulmonary vein without exposure to alveolar oxygen and result in unoxygenated, desaturated systemic arterial blood, polycythemia, cyanosis and clubbing. Death often results from cerebral abscess and rupture of the malformation with massive hemorrhage. Therapeutic intervention is recommended for all symptomatic patients because of the risk of those serious complications. Treatment options include surgery and transcatheter obliteration with steel coils or detachable balloons. Therapeutic embolization has the advantages that multiple bilateral pulmonary arteriovenous fistulas can be occluded and also that the procedure can be repeated if necessary. Recently we experienced a case of the multiple bilateral pulmonary arteriovenous fistulas associated with telangiectatic change of hepatic artery and multiple angiodysplasia on the gastric mucosa in 41 years old female patient who had mild dyspnea of exertion(NYHA class II). clubbing finger, severe iron deficiency anemia. She was treated with embolization technique using steel coils and iron replacement. After the therapeutic embolization. significant improvement of dyspnea of exertion with disappearance of multiple pulmonary nodule on follow-up simple chest x-ray was noted. During the subsequent six months follow-up period, she had the improvement of symptoms and iron deficiency anemia.

• Journal of Society of Preventive Korean Medicine
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• v.20 no.3
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• pp.55-65
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• 2016

Objectives : Mibyeong is a korea medicine have original concept of the disease. However, no previous report has effect of mibyeong herbal medicine in fatigue types of mibyeong. This study investigated the question of whether Dang Gui Bo Hyul-tang(DGBHT) of effect on fatigue types of Mibyeong. Methods : C57BL/6 mice were randomaly divided into three group (n=10). The mice were then group (1) Nocontrol, (2) Restraunt stress(veh), (3) Dang Gui Bo Hyul-tang 200mg/kg. The administered Dang Gui Bo Hyul-tang 200mg/kg or distilled water (orally) 1 hr prior to daily exposure to repeated restraint stress (2 h) for 15 days. The performed behavior test (Mechanical hyperalgesia test,, Open-field test, Forced swimming test, Sucrose preference test and immunostaining and biochemical measured in serum. Results : Stress fatigue induced mices significantly increased lethargic, hyperalgesia through behavior test (Mechanical hyperalgesia test (decrease 43%), Open-field test ($4,809{\pm} 226.13cm$ vs. $3121{\pm}226.64cm$), Forced swimming test ($11.45{\pm}3.96$ vs. $79.10{\pm}8.12sec$), Sucrose preference test (decrease 58%)). In addition, chronic fatigue model evidently increased corticosterone level ($122.54{\pm}18.88$ vs. $186.94{\pm}18.26ng/ml$), AST level ($46.22{\pm}3.23$ vs. $31.40{\pm}3.86U/L$), ALT level ($38.78{\pm}5.72$ vs. $17.60{\pm}1.30$), liver necrosis, lateral ventricle size. These alterations were significantly ameliorated by DGBHT. DGBHT significantly attend the elevated serum concentrations of corticosterone ($155.90{\pm}6.29ng/ml$), AST ($31.40{\pm}3.86U/L$), ALT ($17.60{\pm}1.30U/L$). Moreover, DGBHT improved lethargic, hyperalgesia when compared the stress fatigue (Mechanical hyperalgesia test (improve 28%), Open-field test ($4,038{\pm}615.81cm$), Forced swimming test ($7.56{\pm}1.88sec$), Sucrose preference test (increase 21%) Conclusions : Theses result suggest that DGBHT have improved lethargic, hyperalgesia and fatigue-associated hormone and liver protective on stress fatigue model. It will be necessary to research to present evidences on benefits and effects of Korean medical treatment for Mibyeong through clinical researches based on benefits and effects of those animal models.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.467-474
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• 2018

CBCT is useful for improving the accuracy of the treatment site, but Repeated use increases the exposure dose. In this study, we aimed to provide basic data for dose reduction in CBCT implementation by dataization the simulating and dose reduction effect using shielding substance. Material in this study, Analyzation the photon beam by simulate the CBCT Through MCNPX and then calculate the absorption dose of body organ at shooting moment of thoracic abdominal position as target UF-Revise simulated body. At this time. Dose reduction effects at this time were evaluated according to the texture of materials and presence of shielding materials( lead, antimony, barium, sulfate, tungsten, bismuth). When CBCT was taken without shielding, the dose was calculated to be high in the breast and spine, and the dose in the esophagus and lung was calculated to be low. The doses according to the shield material were calculated as barium sulfate, antimony, bismuth, lead, and tungsten. The shielding rate was the highest in the thymus (73.6%) and the breast (59.9%) compared with the dose reduction according to presence or absence of the shield. However, it showed the lowest shielding rate in lung (2.1%) and spine (12.6%).

• Toxicological Research
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• v.23 no.2
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• pp.151-158
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• 2007

tert-Butyl acetate is an organic solvent used for coatings, industrial cleaning, and surface treatment applications. This study investigated the potential adverse effects of tert-butyl acetate on pregnant dams and embryo-fetal development after maternal exposure on gestational days 6 through 19 in rats. The test chemical was administered to pregnant rats by gavage at dose levels of 0, 500, 1,000, 1,500, and 2,000 mg/kg/day. All dams were subjected to a caesarean section on day 20 of gestation and their fetuses were examined for any external, visceral, and skeletal abnormalities. At 2,000 mg/kg, treatment-related clinical signs, including piloerection, abnormal gait, decreased locomotor activity, loss of fur, reddish tear, anorexia, nasal discharge, vocalization and coma, were observed in a dose-dependent manner. All dams died between the 2nd day and 5th day of treatment due to a severe systemic toxicity. At 1,500 mg/kg, minimal maternal toxicity including an increase in the incidence of decreased locomotor activity and loss of fur, and an increase in the weights of adrenal glands and liver was observed. On the contrary, no significant adverse effect on the embryo-fetal development was detected. There were no adverse effects on either pregnant dams or embryo-fetal development at <1,000 mg/kg. These results show that a 14-day repeated oral dose of tert-butyl acetate in rats caused a minimal maternal toxicity including increases in the incidence of clinical signs and the weights of adrenal glands and liver, but no embryotoxicity and teratogenicity at 1,500 mg/kg/day. Under these experimental conditions, the no-observed-adverse-effect level (NOAEL) of tert-butyl acetate is estimated to be 1,000 mg/kg per day for dams and 1,500 mg/kg per day for embryo-fetal development.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5043-5047
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• 2014

Nowadays increasing effectiveness in cancer therapy and investigation of formation of new strategies that enhance antiproliferative activity against target organs has become a subject of interest. Although the molecular mechanisms of apoptosis can not be fully explained, it is known that cell suicide program existing in their memory genetically is activated by pathophysiological conditions and events such as oxidative stress. Low pressure (hypobaric) conditions that create hypoxia promote apoptosis by inhibiting cell cycling. In this study, determination of the effects of fractional hypobaric applications at different times on HeLa cells at cellular and molecular levels were targeted. Experiments were carried out under hypobaric conditions (35.2 kPa) in a specially designed hypobaric cabin including 2% $O_2$ and 98% N. Application of fractional hypobaric conditions was repeated two times for 3 hours with an interval of 24 hours. At the end of the implementation period cells were allowed to incubate for 24 hours for activation of repair mechanisms. Cell kinetic parameters such as growth rate (MTT) and apoptotic index were used in determination of the effect of hypobaric conditions on HeLa cells. Also in our study expression levels of the Bcl-2 gene family that have regulatory roles in apoptosis were determined by the RT-PCR technique to evaluate molecular mechanisms. The results showed that antiproliferative effect of hypobaric conditions on HeLa cells started three hours from the time of application and increased depending on the period of exposure. While there was a significant decrease in growth rate values, there was a significant increase in apoptotic index values (p<0.01). Also molecular studies showed that hypobaric conditions caused a significant increase in expression level of proapoptotic gene Bax and significant decrease in antiapoptotic Bfl-1. Consequently fractional application of hypobaric conditions on HeLa cell cultures increased both antiproliferative and apoptotic effects and these effects were triggered by the Bax gene.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.5
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• pp.529-535
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• 1997

The present study was aimed at investigating whether the vascular calcium regulation is altered in hypertension. Two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension were made in rats, and their thoracic aortae were taken 4 weeks later. The isometric contractile response and calcium uptake of the endothelium-denuded aortic preparations were determined. Caffeine ($0.1{\sim}35\;mmol/L$) induced a greater contraction in 2K1C and DOCA-salt hypertension than in normotensive control. When the vascular calcium store was functionally-depleted by a repeated exposure to caffeine, it took longer to reload the store and to resume the initial contraction force in response to caffeine in both 2K1C and DOCA-salt hypertension. The vascular $^{45}Ca$ uptake following the functional depletion of the cellular store was also greater in both models of hypertension than in control. Ryanodine, calcium channel activator of the sarcoplasmic reticulum, attenuated the restoration of caffeine-induced vascular contraction, which was not affected by either 2K1C or DOCA-salt hypertension. Nifedipine, an L-type $Ca^{2+}$ channel blocker, attenuated the restoration of caffeine-induced contraction, which was not affected by DOCA-salt hypertension, but was more pronounced in 2K1C hypertension. Nifedipine also diminished the vascular $^{45}Ca$ uptake, which was not affected by DOCA-salt hypertension, but was more pronounced in 2K1C hypertension. Ouabain, a $Na^+,\;K^+-ATPase$ inhibitor, increased the caffeine-induced contraction by a similar magnitude in control and 2K1C hypertension, which was, however, markedly attenuated in DOCA-salt hypertension. Ouabain enhanced the vascular $^{45}Ca$ uptake, the degree of which was not affected by 2K1C hypertension, but was markedly attenuated in DOCA-salt hypertension compared with that in control. Cyclopiazonic acid, a selective inhibitor of $Ca^{2+}-ATPase$ of the sarcoplasmic reticulum, attenuated the restoration of caffeine-induced contraction, which was not affected by 2K1C hypertension, but was more marked in DOCA-salt hypertension. These results suggest that the increased vascular calcium storage may be attributed to an enhanced calcium influx in 2K1C hypertension, and to an impaired $Na^+-K^+$ pump activity of the cell membrane and subsequently increased calcium pump activity of the cellular store in DOCA-salt hypertension.