• The Pure and Applied Mathematics
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• v.19 no.4
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• pp.315-325
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• 2012

Let A and B denote a point, a line or a circle, respectively. For a positive constant $a$, we examine the locus $C_{AB}$($a$) of points P whose distances from A and B are, respectively, in a constant ratio $a$. As a result, we establish some equivalent conditions for conic sections. As a byproduct, we give an easy way to plot points of conic sections exactly by a compass and a straightedge.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.3
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• pp.267-274
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• 2023

Objective: Several particular morphological factors that contribute to the hemodynamics of the anterior communicating artery (ACoA) have been documented, but no study has investigated the role of the degree of anterior cerebral artery (ACA) rotation on the presence of ACoA aneurysms (ACoAAs). Methods: A retrospective study of an institutional aneurysm database was performed; patients with ruptured or nonruptured ACoAAs were selected. Two sex- and age-matched control groups were identified: control Group A (nonaneurysms) and control Group B (middle cerebral artery aneurysms). Measurements of ACA rotation degree were obtained by using a three-dimensional imaging tool. Results: From 2015 to 2020, 315 patients were identified: 105 in the ACoAA group, 105 in control Group A, and 105 in control Group B. The average age at the time of presentation was 64 years, and 52.4% were female. The ACA rotation degree of the ACoAA group was significantly higher than that of control Group A (p <0.01). The A1 ratio and the A1A2 ratio of the ACoAA group were greater than those of control Group A (p <0.01 and p <0.01, respectively). The ACA rotation degree correlated insignificantly with aneurysm size in ACoAA patients (p=0.78). The ACA rotation degree in the ACoAA group was also insignificantly different from that in control B (p=0.11). Conclusions: The degree of ACA rotation was greater in the ACoAA group than in the nonaneurysm group, and it may serve as an imaging marker for ACoAA.

• Journal of Chest Surgery
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• v.45 no.1
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• pp.45-48
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• 2012

We report a case of a postinfarction ventricular septal defect caused by an acute recurrent occlusion after the implantation of a covered stent, which was performed as a rescue procedure for the ruptured left anterior descending artery during a percutaneous coronary intervention. Although the emergent implantation of a covered stent for the ruptured coronary arteries such as the left main coronary artery or the origins of the left anterior descending artery can be performed during a percutaneous coronary intervention, and a coronary bypass surgery should be considered in order to decrease the risk of complete occlusion, thus providing a superior long term patency.

• Neonatal Medicine
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• v.17 no.1
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• pp.132-135
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• 2010

Although the majority of abnormal bleeding during the neonatal period results from acquired coagulation disorders, inherited coagulation disorders can also manifest at this time. Hemophilia is the most common of inherited coagulation disorder. Although 40-70% of cases with hemophilia are diagnosed in the neonatal period, few cases have been reported in premature infants. We report a case of a premature infant born at 31 weeks of gestation, diagnosed with hemophilia A by blood coagulation test, coagulation factor assay and study of the F8 gene. The baby was treated with recombinant factor VIII (Recombinate$^{(R)}$, USA) because of repeated seizures and intramuscular hematoma.

• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.137-144
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• 2019

The Leaders in organization play various core roles in workers' performance and organizational performance. A leader presents a vision and a direction to enable members to achieve higher performance. Especially, transformational leadership suggests members a strong vision and influences them to have identification with the organization. Based on previous researches, transformational leadership is a close connection to identification with job and organization satisfaction. This study explains the influence of the university professors' transformational leadership on students' university satisfaction and university identification. In this study, the subjects of statistical analysis are Chinese international students studying in Korea. As a result, first, professors' transformational leadership enhanced the level of students' university satisfaction. Second, university identification had a partial mediating influence on the relationship between professors' transformational leadership and students' university satisfaction. Professors' transformational leadership had an influence on the students' identification with their universities. Through this process, students become aware of identification and more satisfied with their universities. As a result of the transformational leadership of the professor, the identification and satisfaction of the international students will be improved and they will be better able to adapt to their study life and achieve high results. The purpose of this study is to emphasize the roles of transformational leadership as a necessary leadership for the successful study abroad life of Chinese students studying in Korea today.

• Journal of Yeungnam Medical Science
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• v.30 no.2
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• pp.101-104
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• 2013

Von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary disorder caused by a germline mutation of the VHL gene. It is a multi-systemic disorder that is predisposed to benign or malignant tumors of visceral organs such as hemangioblastoma of the central nervous system, renal cell carcinoma, retinal angioma and pheochromocytoma. We report herein a case of VHL disease that initially manifested with aortic valve insufficiency.

• Journal of Trauma and Injury
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• v.35 no.2
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• pp.131-138
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• 2022

Other than gunshot injuries, sacral penetrating injuries with a foreign body exiting to the other side are extremely rare. We encountered a case of sacral injury in which a long metallic pipe penetrated from the anus into the lower back of a patient. Since the pelvis contains various organs, management of a penetrating injury requires multidisciplinary treatment involving several medical specialties. Due to the infrequency of this type of injury, there are no definitive guidelines for effective management. We described our experience surgically treating a sacral penetrating injury and conducted a literature review. On this basis, we suggest a surgical strategy for treating this type of injury.

• Clinical and Experimental Reproductive Medicine
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• v.40 no.1
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• pp.42-46
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• 2013

Hypochondroplasia (HCH) is an autosomal dominant inherited skeletal dysplasia, usually caused by a heterozygous mutation in the fibroblast growth factor receptor 3 gene (FGFR3). A 27-year-old HCH woman with a history of two consecutive abortions of HCH-affected fetuses visited our clinic for preimplantation genetic diagnosis (PGD). We confirmed the mutation in the proband (FGFR3:c.1620C>A, p.N540K), and established a nested allele-specific PCR and sequence analysis for PGD using single lymphocyte cells. We performed this molecular genetic analysis to detect the presence of mutation among 20 blastomeres from 18 different embryos, and selected 9 embryos with the wild-type sequence (FGFR3:c.1620C). A successful pregnancy was achieved through a frozen-thawed cycle and resulted in the full-term birth of a normal neonate. To the best of our knowledge, this is the first report of a successful pregnancy and birth using single-cell allele-specific PCR and sequencing for PGD in an HCH patient.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2001.10a
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• pp.68-68
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• 2001

no Abstract, See Full Text

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.100.1-100.1
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• 2007

See Full Text