• Journal of Environmental Health Sciences
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• v.37 no.6
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• pp.440-449
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• 2011

Objectives: This study was designed to determine the levels of polybrominated diphenyl ethers (PBDEs) in breast milk and to evaluate the relations with factors affecting these levels. Methods: The congener levels of PBDE in 22 samples of breast milk were analyzed using a high resolution gas chromatograph with a high resolution mass detector. In accordance with our standard operating procedures, the recoveries of internal standards had to range between 68% and 118%. Since the distribution of PBDE concentrations is close to log-normal, the data were logarithmically transformed before analysis. Test subjects were healthy primipara and multipara mothers with a mean age of 32 (SD = 2.7) in 2006. Results: Seven PBDE congeners (BDE-28, 47, 99, 100, 153, 154, and 183) were detected and identified in all of the pooled breast milk samples, indicating widespread contamination from PBDEs in the environment in Korea. Residue levels of total PBDEs (sum PBDEs from tri- to hepta-BDE) ranged from 0.84-13.1 ng/g lipid with median and geometric mean levels of 2.6 ng/g lipid and 2.74 ng/g lipid, respectively. PBDE congeners 47, 99 and 153 markedly predominated and accounted for about 75% of the amount of the PBDE congeners analyzed. BDE-47 was the dominant congener in most samples, whereas BDE-153 was predominant in a few (n = 7/22). BDE-47 was highly correlated with total PBDEs (r = 0.987, p < 0.01). In analyses of the differences of the means of log transformed breast milk PBDE levels for groups of potential covariates, only breast milk BDE-47 and BDE-99 levels were significantly associated with fish (p < 0.05) and meat consumption (p < 0.01). However, we did not find significant correlations between PBDE levels and maternal age, body mass index (BMI), parity, job presence and smoking status. Conclusions: Our findings are mainly limited due to the small sampling size and low doses of PBDEs exposure. Background and human exposure data of PBDEs is lacking, and longitudinal investigations into the environment and biota are encouraged to determine the health impact on future populations in Korea.

• Journal of radiological science and technology
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• v.32 no.1
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• pp.45-52
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• 2009

Digital Mammography is an efficient imaging technique for the detection and diagnosis of breast pathological disorders. Six mammographic criteria such as number of cluster, number, size, extent and morphologic shape of microcalcification, and presence of mass, were reviewed and correlation with pathologic diagnosis were evaluated. It is very important to find breast cancer early when treatment can reduce deaths from breast cancer and breast incision. In screening breast cancer, mammography is typically used to view the internal organization. Clusterig microcalcifications on mammography represent an important feature of breast mass, especially that of intraductal carcinoma. Because microcalcification has high correlation with breast cancer, a cluster of a microcalcification can be very helpful for the clinical doctor to predict breast cancer. For this study, three steps of quantitative evaluation are proposed : DoG filter, adaptive thresholding, Expectation maximization. Through the proposed algorithm, each cluster in the distribution of microcalcification was able to measure the number calcification and length of cluster also can be used to automatically diagnose breast cancer as indicators of the primary diagnosis.

• Tunnel and Underground Space
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• v.21 no.3
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• pp.151-163
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• 2011

The LCM test is one of the most powerful and reliable methods for designing the disc cutter and for predicting the TBM (Tunnel Boring Machine) performance. It has an advantage to predict the actual load on disc cutter from the laboratory test on the real-size large rock samples, however, it also has a disadvantage to transport and/or prepare the large rock samples and to need an extra cost for experiment. Moreover it is not easy to execute the test for jointed rock mass, and sometimes the design model estimated from the test can not be applied to the real design of disc cutter. In order to break this critical point, lots of numerical studies have been performed. PFC2D can simulate crack propagation and rock fragmentation effectively, because it is useful in particle flow analysis. Consequently, in this study, the PFC2D has been adopted for numerical analysis on cutting power of disc cutter according to the different angle of joint, the different direction of joint, and the different space of joint with jointed rock mass models. From the numerical analyses, it was concluded that the bigger cutting power of disc cutter was needed for reverse cutting direction to joint rather than for forward direction, and the cutting power of disc cutter was increased with decreasing the dip angle of joint and decreasing the space of joints in reverse cutting direction. The more precise numerical model for disc cutter can be developed from comparison between the numerical results and LCM test results, and the resonable guideline is expected for prediction of TBM performance and disc cutter.

• Journal of the Korean Applied Science and Technology
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• v.38 no.5
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• pp.1325-1334
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• 2021

This study reports the development of a manufacturing method of synthesizing colloidal gold using catalysts available for cosmetics and an anti-aging ampoule with skin improvement effects using it. Nano-colloidal gold was synthesized by using ascorbic acid and sodium borohydride as a reducing catalyst in hydrogen tetrachloroaurate tetrahydrate. It was confirmed that the particles became smaller as the mass of the content of ascorbic acid, which is a catalyst, increased. On the other hand, as the mass of sodium borohydride increased, the particle size tended to increase. In order to control the colloidal gold reaction rate, particles having 100 to 500 nm of a particle diameter distribution could be obtained using xanthan gum and hydroxyethylcellulose. The optimal synthesis conditions could be obtained by reacting for 1 to 4 hours at 18℃, a reduced pressure state of 20 to 75 mmHg, a stirring speed of 10~50 rpm. The synthesized colloidal gold had a unique smell of dark pink, pH = 5.5, specific gravity of 1.0032, and viscosity of 80 to 310 cps. As an application of skin care cosmetics, anti-aging ampoule has been developed, and it is expected to be used for various prescriptions and formulations using it.

• Journal of the Korean earth science society
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• v.31 no.6
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• pp.600-607
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• 2010

In 2008, multiple episodes of large-scale transport of natural airborne particles and anthropogenically affected particles from different sources in the East Asian continent were identified in the National Oceanic and Atmospheric Administration (NOAA) satellite RGB-composite images and the mass concentrations of ground level particulate matters. To analyze the aerosol size distribution during the large-scale transport of atmospheric aerosols, both aerosol optical depth (AOD; proportional to the aerosol total loading in the vertical column) and fine aerosol weighting (FW; fractional contribution of fine aerosol to the total AOD) of Moderate resolution Imaging Spectroradiometer (MODIS) aerosol products were used over the East Asian region. The six episodes of massive natural airborne particles were observed at Cheongwon, originating from sandstorms in northern China, Mongolia and the loess plateau of China. The $PM_{10}$ and $PM_{2.5}$ stood at 70% and 16% of the total mass concentration of TSP, respectively. However, the mass concentration of $PM_{2.5}$ among TSP increased as high as 23% in the episode in which they were flowing in by way f the industrial area in east China. In the other five episodes of anthropogenically affected particles that flowed into the Korean Peninsula from east China, the mass concentrations of $PM_{10}$ and $PM_{2.5}$ among TSP reached 82% and 65%, respectively. The average AOD for the large-scale transport of anthropogenically affected particle episodes in the East Asian region was measured at $0.42{\pm}0.17$ compared with AOD ($0.36{\pm}0.13$) for the natural airborne particle episodes. Particularly, the regions covering east China, the Yellow Sea, the Korean Peninsula, and the east Korean sea were characterized by high levels of AOD. The average FW values observed during the event of anthropogenically affected aerosols ($0.63{\pm}0.16$) were moderately higher than those of natural airborne particles ($0.52{\pm}0.13$). This observation suggests that anthropogenically affected particles contribute greatly to the atmospheric aerosols in East Asia.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.9.1-10
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• 1981

The clinical study of 183 cases of laryngeal mass was observed and 88 cases of vocal nodule and polyp which is confirmed histopathologically, were clinically classified into 30 cases of vocal nodule, 48 cases of localized vocal polyp, 10 cases of diffuse vocal polyp, and the following results of microscopic examination were obtained. I. The clinical study of laryngeal mass 1. Among total cases of 183, vocal nodule is 82(45%) vocal polyp 53(29%) postintubation granuloma 3(1%) laryngeal papilloma 18(10%) tuberculosis 2(1%) cancer 25(14%). 2. The sex ratio of male to female is 3:4 in vocal nodule, 1:1 in vocal polyp, 1:2 in postintubation granuloma, 3:2 in laryngeal papilloma, 11:1 in cancer. 3. The age distribution is third-fourth decade in vocal nodule, fourth-fifth decade in vocal polyp, third decade in postintubation granuloma, second and fifth decade in laryngeal tuberculosis, sixth decade in laryngeal cancer. 4. The distribution of symptoms is 5 month. -1 year in vocal nodule and polyp, less than 1 year in laryngeal papilloma and postintubation granuloma, 1 year-3 year in laryngeal tuberculosis and cancer. 5. The location of the lesion is between the anterior 1/3 and middle 1/3 in vocal nodule and polyp and papilloma, middle 1/3 and posterior 1/3 in postintubation granuloma, and is diffusely spread on the entire vocal cord in laryngeal tuberculosis and cancer. 6. The side of the lesion is bilateral in vocal nodule and papilloma and the ratio of right to left is 5:3 in vocal polyp, 2:1 in postintubation granuloma. 7. The size is 1~2mm(67%) in vocal nodule, 3~5mm(42%) in vocal polyp, 6~10mm (67%) in postintubation granuloma, 1~2mm (39%) in papilloma, more than 10mm in tuberculosis and cancer. 8. Among the symptoms, the hoarseness is in more than 90% of disease entity, the sore-throat in tuberculosis and cancer, the dyspnea in postintubation granuloma and papilloma and tuberculosis and cancer. 9. In the past history, certain relationship with smoking is noted in cancer (40%) and tuberculosis(50%) and the history of frequent attack of URI is in papilloma(33%). 10. In occupation, certain statistical significance was not noted. II. The histopathological study of vocal nodule and polyp. 1. Most polyps and nodules were covered with stratified squamous epithelium, but focal hyperkeratosis, parakeratosis, acanthosis and atrophy were rather frequently observed. Hyperkeratosis and acanthosis was most frequently seen.

• Journal of Intelligence and Information Systems
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• v.22 no.1
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• pp.119-138
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• 2016

Since the Industrial Revolution, which made the mass production and mass distribution of standardized goods possible, machine-made (manufactured) products have accounted for the majority of the market. However, in recent years, the phenomenon of purchasing even more expensive handmade products has become a noticeable trend as consumers have started to acknowledge the value of handmade products, such as the craftsman's commitment, belief in their quality and scarcity, and the sense of self-esteem from having them,. Consumer interest in these handmade products has shown explosive growth and has been coupled with the recent development of three-dimensional (3D) printing technologies. Etsy.com is the world's largest online handmade platform. It is no different from any other online platform; it provides an online market where buyers and sellers virtually meet to share information and transact business. However, Etsy.com is different in that shops within this platform only deal with handmade products in a variety of categories, ranging from jewelry to toys. Since its establishment in 2005, despite being limited to handmade products, Etsy.com has enjoyed rapid growth in membership, transaction volume, and revenue. Most recently in April 2015, it raised funds through an initial public offering (IPO) of more than 1.8 billion USD, which demonstrates the huge potential of online handmade platforms. After the success of Etsy.com, various types of online handmade platforms such as Handmade at Amazon, ArtFire, DaWanda, and Craft is ART have emerged and are now competing with each other, at the same time, which has increased the size of the market. According to Deloitte's 2015 holiday survey on which types of gifts the respondents plan to buy during the holiday season, about 16% of U.S. consumers chose "homemade or craft items (e.g., Etsy purchase)," which was the same rate as those for the computer game and shoes categories. This indicates that consumer interests in online handmade platforms will continue to rise in the future. However, this high interest in the market for handmade products and their platforms has not yet led to academic research. Most extant studies have only focused on machine-made products and intelligent services for them. This indicates a lack of studies on handmade products and their intelligent services on virtual platforms. Therefore, this study used signaling theory and prior research on the effects of sellers' characteristics on their performance (e.g., total sales and price premiums) in the buyer-seller relationship to identify the key influencing e-Image factors (e.g., reputation, size, information sharing, and length of relationship). Then, their impacts on the performance of shops within the online handmade platform were empirically examined; the dataset was collected from Etsy.com through the application of web harvesting technology. The results from the structural equation modeling revealed that the reputation, size, and information sharing have significant effects on the total sales, while the reputation and length of relationship influence price premiums. This study extended the online platform research into online handmade platform research by identifying key influencing e-Image factors on within-platform shop's total sales and price premiums based on signaling theory and then performed a statistical investigation. These findings are expected to be a stepping stone for future studies on intelligent online handmade services as well as handmade products themselves. Furthermore, the findings of the study provide online handmade platform operators with practical guidelines on how to implement intelligent online handmade services. They should also help shop managers build their marketing strategies in a more specific and effective manner by suggesting key influencing e-Image factors. The results of this study should contribute to the vitalization of intelligent online handmade services by providing clues on how to maximize within-platform shops' total sales and price premiums.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1881-1891
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• 2000

Cenosphere particles of different fly ash formed at the pulverized coal power plant were hollow sphere or filled with small particles inside solid particles. And size was relatively larger than other fly ash particles as well as specific gravity was small to suspend in the water. In this paper, it was demonstrated to contain a variety of morphological particle type, and the physical and chemical properties related to the cenosphere and fly ash particles. Furthermore it was estimated the possibility to reuse the cenosphere particles on the base of cenosphere properties. Cenosphere formation resulted from melting of mineral inclusion in coal, and then gas generation inside the molten droplet. As the aluminosilicate particle was progressively heated, a molten surface layer developed around the solid core. Further heating leaded to cause the formation of fine particles at the core. The mass median diameter(MMD) of cenosphere particles was $123.11{\mu}m$ and the range of size distribution was $100{\sim}200{\mu}m$ with single modal. It was represented that specific density was $0.67g/cm^3$ fineness was $1135g/cm^3$. The chemical components of cenosphere were similar to other fly ash including $SiO_2$, $Al_2O_3$, but the amount of the chemical component was different respectively. In the case of fly ash, $SiO_2$ concentration was 54.75%, and $Al_2O_3$ concentration was 21.96%, so this two components was found in 76.71% of the total concentration. But in the case of cenosphere, it was represented that $SiO_2$ concentration was 59.17% and $Al_2O_3$ concentration was 30.16%, so this two components was found in 89.33% of the total concentration. Glassy component formed by the aluminosilicate was high in the cenosphere, so that it was suitable to use insulating heat material.

• Korean Journal of Head & Neck Oncology
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• v.14 no.2
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• pp.228-235
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• 1998

Objectives: Papillary microcarcinoma of the thyroid was evaluated as to the effectiveness of diagnostic modalities, lymphatic spread pattern, and therapeutic decision according to tumor size. Material and Methods: We retrospectively analyzed a clinicopathologic findings of 72 papillary microcarcinoma patients who were treated at the over 11 years between 1985 and 1995. The authors divided papillary microcarcinoma of the thyroid into two subgroups according to tumor size: $0{\leqq}5mm$ and $5<0{\leqq}10mm$. An analysis including age and gender distribution, diagnostic tools(thyroid sonogram, thyroid scan, thyroid function test, fine needle aspiration cytology, frozen section), pathological examination of lymphnode, and surgical procedures was carried out in each subgroups. Results: The carcinoma of smaller than 5mm were found in 32 patients, and of 6 -10mm were in 40 patients. The average age of patients was 45years and all of them were female. Cold nodules on thyroid scan were noticed in 53 patientss and normal findings were in 15 patients. Suspicious malignant lesions(fine calcification, solid mass, irregular margin) on thyroid sonography were detected in 23 patients and the sonography was more useful in detecting $0{\leqq}5mm$ small sized lesions than other diagnostic methods. FNAC were performed in 17 patients, and 7 patients were diagnosed as having thyroid papillary cancer. But diagnotic rate in $0{\leqq}5mm$ small sized lesions was very low(one of eights).Frozen section were performed in all patients, among these 15 patients were diagnosed as being benign diseases and false negative rates were higher in $0{\leqq}5mm$ small sized lesions than in $5<0{\leqq}10mm$ sized lesions(p-value<0.006). Only thyroidectomies were performed in 24 patients and thyroidectomy with node dissections in 48 patients. The lymphnode metastatic rates were much higher in multifocal lesions(61.5%) than in single lesion. The incidence of cervical lymphnode metastasis was 19.4% in $0{\leqq}5mm$ sized lesions and 47.9% in $5<0{\leqq}10mm$ sized lesions. Postoperative management were performed with TSH suppression therapy(T4, synthroid) in all patients and RI therapy in 29 patients. Conclusion: On the basis of our study, improved preoperative diagnostic tools for papillary microcarcinoma of the thyroid was helpful in the choice of surgical treatment. As a result of techninological progress(ultrasonography, FNAC), the pencentage of the discovery of papillary microcarcinoma has been increased. The thyroid ultrasonography was useful in detecting small sized lesions($0{\leqq}5mm$), but FNAC may not be beneficial in detecting small sized lesions($0{\leqq}5mm$). In the surgical procedure, thyroid lobectomy alone should be avoided because of the high rate of bilaterality and multifocality.

• Journal of Gastric Cancer
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• v.4 no.2
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• pp.126-130
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• 2004

Purpose: A Krukenberg tumor is an ovarian tumor of a signet-ring cell type. This tumor arises more commonly in young women, and the prognosis is poor. The primary focus of this tumor is often found at gastrointestinal malignancy, especially gastric cancer. We tried to identify the clinical characteristics of this tumor, and in that regard, this report might be helpful. Materials and Methods: We reviewed the 61 patients with Krukenberg tumors, who had been diagnosed at our hospital from 1994 to 2002, and retrospectively analyzed the clinical features. Results: The age distribution ranged from 15 to 59 years, and the mean age was 41 years. The most common symptom was a lower abdominal mass ($46\%$). Fourty-two cases ($77\%$) showed bilateral ovarian involvement, and the size of this tumor was variable, but in 24 cases ($4\%$) the size was $5\∼10$ cm for the largest diameter. Among 54 cases, 40 cases had ascites, and the volume of ascites was variable. The median survival of the 61 patients was 10 months, and Krukenberg tumor developed 19.7 months after the primary operation. The median survival durations of recurrence patterns were 20 months for the Krukenberg tumor alone, and 7 months for the Krukenberg tumor with peritoneal seeding. Conclusion: In young women treated with a gastrectomy, especially one for an advanced tumor, closed observation with abdominal ultrasonography or computed tomography to detect a Krukenberg tumor is recommended. The patient with a Krukenberg tumor alone has a better prognosis than one with a Krukenberg tumor combined peritoneal seeding. We will have to consider more progressive treatment for the patient with a Krukenberg tumor alone.