• Journal for History of Mathematics
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• v.22 no.1
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• pp.89-110
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• 2009

This paper observed the effect of CAS calculator usage while studying algebra on the achievement of low-achievement students. Participants were composed of 70 low-achievement tenth grade students from a high school located in a metropolitan city. That had never used a mathematics educational calculator before. Target participants were divided into two groups: an experiment group that studied activity papers with the aid of a CAS calculator, and a control group that studied the same activity papers using only paper-and-pencil. The content of the activity papers for the two groups was the same, but the structure differed. Content consisted of numbers and operations, equations and inequalities(character and expressions), and functions. Students in the experiment group exhibited matacognition learning using a CAS calculator. The two groups completed mathematics achievement tests both before and after the activity papers. Therefore, ANCOVA analysis results showed that compared to the pretest, results of the experiment group improved considerably more than the control group.

• Korean Journal of Head & Neck Oncology
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• v.1 no.1
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• pp.35-61
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• 1985

The surgical treatment of advanced carcinomas and some benign tumors having clinically malignant behaviors of the head and neck region often require extensive resection, necessitating large flaps for reconstruction. Since the original upper arm flap was described by Tagliacozzi in 1597, a variety of technique such as random pattern local flap, axial flap, distant flap, scalping flap, myocutaneous flap, free flap etc. have been proposed for reconstruction of head, face and neck defects. Reconstruction of the facial defects usually require the use of distant tissue. Traditionally, nasal reconstruction has been carried out with a variety of forehead flaps. In recent years, there has been more acceptance of immediate repairs following the removal of these tumors. As a result, patients are more willing to undergo these extensive resections to improve their chances of cure, with the reasonable expectation that an immediate reconstruction will provide an adequate cosmetic result. Authors experienced 13 cases of head and neck tumor during last three and half years that required wide excision and immediate reconstruction with various flaps, not with primary closure or simple skin graft. We present our experience with varied flaps for reconstruction after wide resection of head and neck tumors 3 cases of defect of dorsum of nose or medial canthus with island forehead flaps, lower eyelid defect with cheek flap, cheek defect with Limberg flap, orbital floor defect with Temporalis muscle flap, lateral neck defects with Pectoralis major myocutaneous flap or Latissimus dorsi myocutaneous free flap, subtotal nose defect with scalping flap, wide forehead defect with Dorsalis pedis free flap and 3 cases of mandibular defect or mandibular defect combined with lower lip defect were reconstructed with free vascularized iliac bone graft or free vascularized iliac bone graft concomitantly combined with free groin flap pedicled on deep circumflex iliac vessels We obtained satisfactory results coincided wi th goal of treatment of head and neck tumors, MAXIMAL CURE RATE with MINIMAL MORBIDITY, OPTIMAL FUNCTION, and an APPEARANCE as close to normal as possible.

• Journal of Educational Research in Mathematics
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• v.25 no.4
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• pp.473-498
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• 2015

The purpose of this study is to examine thinking process of the mathematically gifted students and how invariants affect the construction and discovery of curve when carry out activities that produce and reproduce the algebraic curves, mathematician explored from the ancient Greek era enduring the trouble of making handcrafted complex apparatus, not using apparatus but dynamic geometry software. Specially by trying research that collect empirical data on the role and meaning of invariants in a dynamic geometry environment and research that subdivide the process of utilizing invariants that appears during the mathematically gifted students creating a new curve, this study presents the educational application method of invariants and check the possibility of enlarging the scope of its appliance.

• Journal of Educational Research in Mathematics
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• v.26 no.4
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• pp.715-730
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• 2016

The purpose of this study is to analyze Descartes's point of view on the mathematical connection of algebra and geometry which help comprehend the traditional frame with a new perspective in order to access to unsolved problems and provide useful pedagogical implications in school mathematics. To achieve the goal, researchers have historically reviewed the fundamental principle and development method's feature of analytic geometry, which stands on the basis of mathematical connection between algebra and geometry. In addition we have considered the significance of geometric solving of equations in terms of analytic geometry by analyzing related preceding researches and modern trends of mathematics education curriculum. These efforts could allow us to have discussed on some opportunities to get insight about mathematical connection of algebra and geometry via geometric approaches for solving equations using the intersection of curves represented on coordinates plane. Furthermore, we could finally provide the method and its pedagogical implications for interpreting geometric approaches to cubic equations utilizing intersection of conic sections in the process of inquiring, solving and reflecting stages.

• The Journal of the Korean Society for Microbiology
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• v.7 no.1
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• pp.21-27
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• 1972

A simple and effective procedure is described for semi-purification of viable Myco. leprae from biopsied lepromatous nodules by trypsinization and high-speed centrifugation. An unique characteristic of this method is a complete omission of conventional grinding or homogenization of minced lepromatous tissues prior to purification. Inoculation of trypsin-purified preparation of Myco. leprae into foot pads and ear lobes of Korean chipmunk(Tamias sibiricus asiaticus, Gmelin) resulted in apparent increases in total number of acid-fast bacilli per inoculated tissue 8 and 12 months after inoculation.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.350-361
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• 2018

Hypercholesterolemia is one of the primary risk factors for cardiovascular diseases. The use of lactobacilli probiotics to reduce blood cholesterol levels have been extensively reported. However, more information is needed to evaluate the possible mechanisms involved and to identify possible targets for further therapeutic development. In this study, strains of lactobacilli were screened based on the ability to assimilate cholesterol, and prevention of cholesterol accumulation in hepatic (HepG2) and intestinal (HT-29) cells. Cell free supernatant (CFS) from Lactobacillus plantarum DR7 showed a higher ability to assimilate cholesterol, reduction in cholesterol accumulation in both HepG2 and HT-29 cells, accompanied by reduced mRNA expression of HMG-CoA reductase (HMGCR) in HepG2 (p<0.05), compared to other lactobacilli. The reduction of HMGCR expression was also diminished in the presence of an AMPK inhibitor (Compound C), suggesting that L. plantarum DR7 exerted its effect via the AMPK pathway, typically via the phosphorylation of AMPK instead of the AMPK mRNA expression in HepG2 (p<0.05). Altogether, our present study illustrated that lactobacilli could exert cholesterol lowering properties along the AMPK pathway, specifically via phosphorylation of AMPK that led to reduced expression of HMGCR.

• School Mathematics
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• v.6 no.4
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• pp.411-433
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• 2004

Many researchers have reported that 7th graders have severe difficulties in using letters and algebraic expressions. This study investigated the way Microsoft Excel contributes to student's understanding of letters and algebraic expressions. For six hours through two weeks, four 7th grade students experienced various activities with Excel after school and both before and after the experimentation, the interviews to check their understanding was conducted. The results were as follows; First, after the experimentation, students used various letters to express formulas and recognized that letters represent not only some objects but also changing objects. Also they accepted that same objects could be represented by different letters and different objects could be represented by the same letters. Second, Excel improved students' abilities to discriminate variables and invariables in the problem and to find mathematical relationships among variables. And with Excel students could divide the whole calculation procedure into several steps in order to handle it more easily. Also, Excel made immediate numerical feedback possible and it made students express the calculation in a more formalized way than a paper and pencil environment did.

• Archives of Plastic Surgery
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• v.35 no.3
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• pp.255-260
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• 2008

Purpose: Tongue cancer is the most common malignant tumor of the oral cavity and the ultimate goal in treatment of the cancer is not only complete excision and meticulous closure of the wound, but also, reconstruction of a demensional and functional tongue. Our study focuses on various factors, such as defect size, extent of tumor, age, application of mandibulectomy or radiotherapy, and their influences on postoperative speech and swallowing function. Methods: Our study was based on 59 patients who underwent tongue cancer operation and reconstruction of the tongue. Speech and swallowing were evaluated according to categories documented by Sultan and Teichgraeber. Patients were classified into 3 groups as partial glossectomy, hemiglossectomy and total glossectomy groups for evaluation. The average age of the patients were 51, and the mean follow-up period was 4 years 2 months. Results: The partial glossectomy group showed statistically relevant results for speech articulation and swallowing abilities compared to the total glossectomy group. In cases of defects involving the mouth floor, the group showed decreased results compared to the group without mouth floor involvement. Increased age showed decreased postoperative results with statistical significance, while mandibulectomy and radiotherapy revealed no statistically significant data. Analysis according to TNM staging resulted in decreased functional result with advanced staging without statistical significance. Conclusion: To summarize the factors influencing the functional outcome in tongue reconstruction, younger patients and early stage cancer with minimal surgical extent revealed more satisfying results while mandibulectomy and radiation did not have influence on our analysis. Addition of various influencing factors and studies with longer follow up periods on our patient groups may provide effective data for more satisfying functional outcomes in the future.

• Archives of Plastic Surgery
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• v.35 no.3
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• pp.283-288
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• 2008

Purpose: The purpose of this study is to evaluate the transverse cervical artery of those who received preoperative radiotherapy or radical neck dissection and those who are unable to utilize the branch of external carotid artery system, which are most commonly used as recipient artery in head and neck reconstruction. Methods: 10 patients were selected as head and neck cancer candidates for study. 8 patients received radical neck dissection or modified radical neck dissection and 3 patients underwent preoperative radiotheraphy. In call cases, reconstruction using free flap was performed with transverse cervical artery as recipient artery and posterolateral cervical vein or transverse cervical vein as recipient vein. Results: Partial necrosis of flap due to wound infection was noted in one case and successful microsurgery was achieved in all other cases. The average pedicle length was 9.3 cm and all arteries underwent end to-end anastomosis. In 7 patients, posterolateral cervical vein was used as recipient artery and transverse cervical vein was utilized in 3 patients. Conclusion: In cases where recipient artery from external carotid system cannot be utilized due to preoperative radiotherapy or radical neck dissection, the transverse cervical artery can be an alternative option of choice. Due to diverse variations of transverse cervical vein as a recipient vein, the posterolateral cervical vein may be considered in such cases.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.526-530
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• 2010

Purpose: With the recent recognition of the importance of soft-tissue fillers, fat grafting has been assumed an increasingly important role as both an adjunctive and a primary procedure in aesthetic and reconstructive surgery. The main problem in achieving long-term soft-tissue augmentation is partial absorption of the injected fat and hence the need for overcorrection and re-injection. The purpose of this study is to improve the viability of the injected fat by the use of Lipo-PGE1. Methods: Human adipose tissue, obtained by suctionassisted lipectomy, was re -injected into the subcutaneous layer in the scalp of ICR mice. Lipo-PGE1 ($0.5{\mu}g$/kg) was injected intravenously in experimental group for 7 days from the operation day and saline was injected in control group. There were 5 animals in each group. The animals were euthanized 4 weeks after the procedure. Graft weight and volume were measured and histologic evaluation was performed. Result: Histologic analysis demonstrated significantly less cyst formation and less inflammatory reaction in the group treated with Lipo-PGE1. No significant difference was found between the groups regarding graft volume or the other histologic parameters investigated. Significant differences were demonstrated in microvascular density count. Conclusion: Less cyst formation, less inflammation, more angiogenesis indicating improved quality of the injected fat can be obtained by the addition of Lipo-PGE1. Further studies of various dosages of Lipo-PGE1 and their long-term effect are required before these encouraging results could be applied clinically.