• Mass Spectrometry Letters
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• v.12 no.1
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• pp.1-10
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• 2021

A simple, specific, and economical LC-MS/MS method was investigated for the screening of 43 prescribed antihypertensive and related drugs in human urine. The urine samples were simply prepared by diluting and mixing with internal standard before directly introduced to the LC-MS/MS system, which is fast, straightforward, and cost-effective. Fractional factorial, Box-Behnken, and I-optimal design were applied to screen and optimize the mass spectrometric and chromatographic factors. The analysis was carried out on a triple quadrupole mass spectrometer system utilizing multiple reaction monitoring with positive and negative electrospray ionization method. Chromatographic separation was performed on a Thermo Scientific Accucore RP-MS column (50 × 3.0 mm ID., 2.6 ㎛) using two separate gradient elution programs established with the same mobile phases. Chromatographic separation was performed within 12 min. The optimal method was validated based on FDA guideline. The results indicated that the assay was specific, reproducible, and sensitive with the limit of detection from 0.1 to 50.0 ㎍/L. The method was linear for all analytes with coefficient of determination ranging from 0.9870 to 0.9981. The intra-assay precision was from 1.44 to 19.87% and the inter-assay precision was between 2.69 and 18.54% with the recovery rate ranges from 84.54 to 119.78% for all drugs measured. All analytes in urine samples were stable for 24 h at 25℃, and for 2 weeks at -60℃. The developed method improves on currently existing methods by including larger number of cardiovascular medications and better sensitivity of 12 analytes.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.74-77
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• 2010

Antibiotic-resistant Staphylococcus aureus is beginning to pose a social issue. Thus, there is an urgent need for the development of effective anti-staphylococcal agents to eradicate antibiotic-resistant S. aureus in food systems and to treat the pathogen in clinical areas. To address this need, lactic acid bacteria (LAB) from kimchi were screened for the production of anti-staphylococcal bacteriocin. From this screening, a bacteriocin generated by the MK3 strain, which was identified by 16S rRNA gene sequence analysis as Enterococcus faecium, demonstrated antimicrobial activity against an S. aureus strain, and was designated enterocin MK3. Enterocin MK3 also demonstrated activity against other gram-positive bacteria, including several LAB and Listeria monocytogenes, but not gram-negative Escherichia coli. The molecular mass of enterocin MK3 was estimated as approximately 6.5 kDa on an SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) gel.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.1
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• pp.43-45
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• 2002

We have theoretically investigated steady-state carrier transport and current self-oscillation in negative-effective-mass (NEM) p$\^$+/pp$\^$+/diodes. The current self-oscillation here is a result of the formation and traveling of electric field domains in the p base having a NEM. The dependence of self-oscillating frequency on the applied dc voltage is obtained by detailed numerical simulations. In the calculations, we have considered the scatterings by carrier-impurity, carrier-acoustic phonon, carrier-polar-phonon, and carrier-nonpolar-phonon-hole interactions . This kind of NEM oscillator allows us to reach a current oscillation with terahertz frequency, thus it may be used as a broadband source of terahertz radiation.

• Analytical Science and Technology
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• v.23 no.4
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• pp.405-413
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• 2010

A new method for the simultaneous determination of six glucocorticoids (betamethasone, dexamethasone, prednisone, prednisolone, methylprednisolone, and flumethasone) in meats (bovine muscle, bovine liver) were established. Samples were effectively extracted using C18 cartridge with ethylacetate. Chromatographic separation was achieved using C18 column and negative electrospray ionization mass spectrometry was performed in the Multiple Reaction Monitoring mode for the effective quantitation and qualification of glucocorticoids. Acetonitrile and water (0.1% formic acid) were used as mobile phase and additive for effective electrospray ionization, and gave good chromatographic separation and mass spectrometric sensitivity. The limit of detection (LODs) and the limit of quantitation (LOQs) in spiked blank samples depending on types of matrix and pharmaceuticals were ranged from 0.2 to $1.0\;{\mu}g$/kg and 0.8 to $3.4\;{\mu}g$/kg, respectively. And the recoveries were between 89.5 to 119.6%. The established method showed good recoveries, accuracies, precisions and fast sample preparation and it will be applied to assay of glucocorticoids residues in meat.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.31-36
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• 1994

We studied 65 patients with hypercalcemia who had heed performed $^{201}Tl/^{99m}Tc$ subtraction scan, 21 of them were confirmed as parathyroid tumor (19 adenoma, 2 carcinoma). The diagnostic sensitivity of $^{201}Tl/^{99m}Tc$ subfraction scan for detecting parathyroid mass was 90.5%, specificity was 97.6%, ultrasonography was 80.6%, 58.8%, respectively. The causes of two false negative cases were relatively small size ($1.5{\times}1{\times}0.8cm$) compared to remainig cases and poor thallium uptake due to cystic necrosis of parathyroid adenoma. The one false positive case was non-functioning thyroid nodule. $^{201}Tl/^{99m}Tc$ subtraction scan was simple, effective diagnostic tool and superior to ultrasonography for evaluating the parathyroid mass with high sensitivity and specificity.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.345-349
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• 2015

Background: To determine the cut-off values of the preoperative risk of malignancy index (RMI) used in differentiating benign or malignant adnexal masses and to determine their significance in differential diagnosis by comparison of different systems. Materials and Methods: 191 operated women were assessed retrospectively. RMI of 1, 2, 3 and 4; cut-off values for an effective benign or malignant differentiation together with sensitivity, specificity, negative and positive predictive values were calculated. Results: Cut-off value for RMI 1 was found to be 250; there was significant (p<0.001) compatibility at this level with sensitivity of 60%, positive predictive value (PPV) of 75%, specificity of 93%, negative predictive value (NPV) of 88% and an overall compliance rate of 85%. When RMI 2 and 3 was obtained with a cut-off value of 200, there was significant (p<0.001) compatibility at this level for RMI 2 with sensitivity of 67%, PPV of 67%, specificity of 89%, NPV of 89%, histopathologic correlation of 84% while RMI 3 had significant (p<0.001) compatibility at the same level with sensitivity of 63%, PPV of 69%, specificity of 91%, NPV of 88% and a histopathologic correlation of 84%. Significant (p<0.001) compatibility for RMI 4 with a sensitivity of 67%, PPV of 73%, specificity of 92%, NPV of 89% and a histopathologic correlation of 86% was obtained at the cut-off level 400. Conclusions: RMI have a significant predictability in differentiating benign and malignant adnexal masses, thus can effectively be used in clinical practice.

• Journal of Nutrition and Health
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• v.34 no.3
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• pp.313-321
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• 2001

The purpose of this study is to verify the relation between vegetarian diet and the risk factors of cardiovascular disease. To do the present study the vegetarians were selected;245 Buddhist nuns(age: 23-79yrs). For control subjects, 235 healthy female adults(age: 23-79yrs) were selected. They were the teachers, the nurses and the housekeepers living in Chinju Gyeongsang Namdoo Province. Study period was from October 1996 to February 1997. The contents are consist of survey, anthropometric measurement, and clinical examination. The average ages of the subjects were 44.20yrs for vegetarians and 40.52yrs for non-vegetarians respectively. Average body mass indice(BMI) of vegetarians and non-vegetarians were 22.47 and 21.08, WHR was 0.85 and 0.84, percentage of body fat was 28.79 and 26.55 and the average duration of vegetarian diet of the vegetarians was 13.16 years. On the nutrient related lipid, fat, the energy ratio of fat, saturated fatty acid, total fatty acid, monounsaturated fatty acid and total-cholesterol were significantly lower(p<0.01) but the ratio of p/s was significantly higher(p<0.01) in vegetarians than non-vegetarians. The vegetarians were significantly higher than the non-vegetarians in intake of fiber, vitamin C. In vegetarians, variables that significant negative correlation with fiber were total-cholesterol, AI, blood sugar. In non-vegetarians, variables that significant negative correlation with fiber were TG, total-cholesterol, blood sugar, systolic blood pressure. In both subjects, the serum lipid concentration and the blood pressure were getting lower with fiber intakes. Consequently, vegetable diet can be considerably effective in making the level of the risk factors causing in cardiovascular disease lower. (Korean J Nutrition 34(3) : 313∼321, 2001)

• Journal of the Korean School Mathematics Society
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• v.23 no.1
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• pp.111-127
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• 2020

In many studies, mathematics anxiety (MA) is a major factor affecting students' mathematical achievement (MC) and is reported to have a greater negative effect on female students. In the study, we developed a complex treatment program consisting of 10 lesson units, to reduce mathematic anxiety and applied it to 26 male and female students with high MA. For this purpose, we analyzed the differences between the two gender groups collected by the Math Anxiety Scale for Students(MASS) and Mathematical Achievement Scale(MCS) before and after. As a result of the treatment program, MA was decreased in both groups, but only female students scored higher in MC. The program that had been effective for both boys and girls in MA satisfied the main purpose of which was to treat MA with integrated mathematical and psychological aspects, and implied that additional procedures and guidance should be followed for boys' MC.

• Korean Journal of Head & Neck Oncology
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• v.19 no.1
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• pp.67-70
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• 2003

Out of entire salivary tumor, 1.7% are malignant lymphoma developed in salivary gland and it is usually mucosa associated lymphoid tissue (MALT) lymphoma developed in salivary gland. In the case of Non-Hodgkin lymphoma, the most frequently involved extanodal sites of diffuse large B cell lymphoma are bone, skin, thyroid, gastrointestinal tract, and lung. Development in salivary gland is very rare. A 69 years old male patient who have found Lt. submandibular gland (SMG) mass a month ago is suspected of malignancy from his FNA result, so histologic exam by SMG resection was operated. According to histopathologic exam, large B cell lymphocyte infiltratration were generally shown as diffuse and lymphoepitheliallesion were not found. In immunostaining, CD79a showed positive and CD3, CAM5.2 showed negative which diagnosed as diffuse large B cell lymphoma. As Ann Arbor stage I, CEOP-B chemotherapy was used 3 times as treatment without any recurrence. In the case of malignant lymphoma in salivary gland, it develops as painless mass in ipsilateral side. If found in parotid gland, it is rare to have facial nerve falsy and pathologically diagnosed as lymphocytes of abnormal type of monoclonal immunostaining must be provided as evidence. Combined therapy is known as most effective treatment for intermediate grade.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.262-266
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• 2009

Solitary fibrous tumor (SFT) is a neoplasm that arises most commonly in pleura. Although SFT occasionally occurs in extrapleural locations, the incidence in the oral cavity is rare. SFT is benign in almost cases and surgical excision is the effective treatment. SFT occurred in the left cheek of a 60-year-old man presented with a painless submucosal mass. The tumor was surgically removed. Immunohistochemical study showed that tumoral cells were negative for SMA, S-100, but positive for Bcl-2, CD34. SFT is easily over-diagnosed if strict criteria are not carefully applied, and strict diagnostic criteria are necessary to avoid confusion of SFT with more aggressive lesions.