• Journal of Ecology and Environment
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• v.36 no.4
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• pp.449-463
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• 2013

DNA barcoding is becoming a widely applied tool to accurately discriminate red algae. We tested the effectiveness of DNA barcoding for identification and discovery of Champia species in Korea and clarified the phylogenetic relationships using the plastid rbcL gene. As results, we described four species of Champia such as C. inkyua sp. nov., C. recta Noda, C. bifida Okamura, and C. expansa Yendo. A new species, C. inkyua, is characterized by entangled thallus, terete and irregular branches, hooked apices, and longitudinal filaments running throughout the frond periphery only. Longitudinal filaments were composed of a complete cell with two half cells between diaphragms in the cavity. C. recta and C. bifida were reinstated with previously used names of C. parvula and C. compressa, respectively. C. recta is the first recorded species from Korea and is characterized by an erect thallus, terete and irregular branches, and straight apices. C. bifida is characterized by compressed thallus, pinnate or alternate branches, and bifid apices. C. expansa is characterized by flabellate thallus and dichotomous branches. Molecular analyses of COI and rbcL genes revealed sufficient sequence divergence to warrant species recognition in the genus Champia.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1363-1366
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• 2006

Aneurysmal dilatation of the ductus arteriosis has been considered a rare but potentially fatal abnormality. The mechanism of ductal aneurysmal formation remains uncertain. Plain chest radiography has proven helpful in the diagnosis of ductus arteriosus aneurysm (DAA), before the application of transthoracic echocardiography. The transthoracic echocardiography is an important tool for the diagnosis and follow-up of DAA. We present a case of congenital ductus arteriosus aneurysm in a newborn, that was an incidental discovery. The diagnosis was made by echocardiography, three-dimensional surface rendering computed tomography (CT), and spontaneous regression after four weeks of follow-up.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.118-127
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• 2020

The paper introduces trends and methodological challenges of quantitative Korean text analysis by using the case studies of academic and news media articles on "migration" and "immigration" within the periods of 2017-2019. The quantitative text analysis based on natural language processing technology (NLP) and this became an essential tool for social science. It is a part of data science that converts documents into structured data and performs hypothesis discovery and verification as the data and visualize data. Furthermore, we examed the commonly applied social scientific statistical models of quantitative text analysis by using Natural Language Processing (NLP) with R programming and Quanteda.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.360-372
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• 2020

Objective: Specific genomic sites can be recognized and permanently modified by genome editing. The discovery of endonucleases has advanced genome editing in pigs, attenuating xenograft rejection and cross-species disease transmission. However, off-target mutagenesis caused by these nucleases is a major barrier to putative clinical applications. Furthermore, off-target mutagenesis by genome editing has not yet been addressed in pigs. Methods: Here, we generated genetically inheritable α-1,3-galactosyltransferase (GGTA1) knockout Yucatan miniature pigs by combining transcription activator-like effector nuclease (TALEN) and nuclear transfer. For precise estimation of genomic mutations induced by TALEN in GGTA1 knockout pigs, we obtained the whole-genome sequence of the donor cells for use as an internal control genome. Results: In-depth whole-genome sequencing analysis demonstrated that TALEN-mediated GGTA1 knockout pigs had a comparable mutation rate to homologous recombination-treated pigs and wild-type strain controls. RNA sequencing analysis associated with genomic mutations revealed that TALEN-induced off-target mutations had no discernable effect on RNA transcript abundance. Conclusion: Therefore, TALEN appears to be a precise and safe tool for generating genomeedited pigs, and the TALEN-mediated GGTA1 knockout Yucatan miniature pigs produced in this study can serve as a safe and effective organ and tissue resource for clinical applications.

• Journal of Genetic Medicine
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• v.12 no.2
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• pp.72-78
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• 2015

Recently, noninvasive prenatal test (NIPT) has been adopted as a primary screening tool for fetal chromosomal aneuploidy. The principle of NIPT lies in isolating the fetal fraction of cell-free DNA in maternal plasma and analyzing it with bioinformatic tools to measure the amount of gene from the target chromosome, such as chromosomes 21, 18, and 13. NIPT will contribute to decreasing the need for unnecessary invasive procedures, including amniocentesis and chorionic villi sampling, for confirming fetal aneuploidy because of its higher positive predictive value than that of the conventional prenatal screening method. However, its greater cost than that of the current antenatal screening protocol may be an obstacle to the adoption of this innovative technique in clinical practice. Digital polymerase chain reaction (dPCR) is a novel approach for detecting and quantifying nucleic acid. dPCR provides real-time diagnostic advantages with higher sensitivity, accuracy, and absolute quantification than conventional quantitative PCR. Since the groundbreaking discovery that fetal cell-free nucleic acid exists in maternal plasma was reported, dPCR has been used for the quantification of fetal DNA and for screening for fetal aneuploidy. It has been suggested that dPCR will decrease the cost by targeting specific sequences in the target chromosome, and dPCR-based noninvasive testing will facilitate progress toward the implementation of a noninvasive approach for screening for trisomy 21, 18, and 13. In this review, we highlight the principle of dPCR and discuss its future implications in clinical practice.

• Research in Mathematical Education
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• v.5 no.2
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• pp.107-118
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• 2001

Mathematics subject of the seventh national curriculum in Korea, which has been effective since 2000, strongly encourages the use of calculators and computers to help children gain a better understanding of basic mathematical concepts and develop creative thinking and problem-solving skills without spending too much time and effort on making mechanical computations. Despite the recommendation by the national curriculum, however, only a small segment of elementary school teachers have been using calculators because of the fear that children\\`s dependence on calculators might bring about negative consequences. As a result, little research has been conducted in this area as well. This study has been conducted on the assumption that calculators have the potential for being a useful instructional tool in certain areas of elementary school mathematics education. To investigate the usefulness of calculators, a review was made of the scanty literature in the area. The literature review indicated that calculators are effective when they are used for the following purposes: understanding concepts and properties in numbers and operations, deducing mathematical rules, and solving problems. In view of the available research finding, we will give some concrete learning and teaching models of such uses of calculators. The teaching-learning models are organized around three categories: concept formation, discovery of principles and rules, and problem solving. Such organization is intended to help teachers use the models with ease.

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.95-95
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• 2013

The NdFeB magnet can be classified into the sintered magnet and bonded magnet. The former has superior magnet characteristics but the degree of freedom in shape is highly restricted, whereas the latter has a high degree of freedom, but its magnet characteristics are inferior to the former. When a NdFeB magnet is used at the elevated temperature, part of Nd must be replaced with a high priced Dy to increase its coercive force. For these reasons, a Dy free and high performance NdFeB bonded magnet is desired strongly. The author successfully developed a Dy free NdFeB anisotropic bonded magnet based on discovery of new phenomena called as d-HDDR reaction and its mass production process such as a thermally balanced hydrogen reaction furnace, micro capsuled powder, compression molding / injection molding under magnetic field, magnetic die and so on. Applied to DC brush seat motor for automotive use, the motor has become 50% small in size and weight. The commercialization of a half sized motor for automotive use has been realized up to the market share of 30%. At present, its commercialization is extending to various types of motors such as power tool, ABS motor, wiper motor, window motor, electric bike power motor, and compressor motor. It is expected that the applications will be increasingly enlarged to EV motor, wind generator, EPS motor, washing machine, and glass cutting machine. This innovative technology has realized Dy free high performance magnet and mudt make big contribution to not only rare element strategies but also energy conservation.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1742-1750
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• 2003

In order to characterize the hydrophobic parameters of N-acetyl amino acid amides in 1-octanol/water, a theoretical calculation was carried out using a solvation free energy density model. The hydrophobicity parameters of the molecules are obtained with the consideration of the solvation free energy over the solvent volume surrounding the solute, using a grid model. Our method can account for the solvent accessible surface area of the molecules according to conformational variations. Through a comparison of the hydrophobicity of our calculation and that of other experimental/theoretical works, the solvation free energy density model is proven to be a useful tool for the evaluation of the hydrophobicity of amino acids and peptides. In order to evaluate the solvation free energy density model as a method of calculating the activity of drugs using the hydrophobicity of its building blocks, the contracture of Bradykinin potentiating pentapeptide was also predicted from the hydrophobicity of each residue. The solvation free energy density model can be used to employ descriptors for the prediction of peptide activities in drug discovery, as well as to calculate the hydrophobicity of amino acids.

• Molecules and Cells
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• v.27 no.2
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• pp.225-235
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• 2009

Antibody phage display provides a powerful and efficient tool for the discovery and development of monoclonal antibodies for therapeutic and other applications. Antibody clones from synthetic libraries with optimized design features have several distinct advantages that include high stability, high levels of expression, and ease of downstream optimization and engineering. In this study, a fully synthetic human scFv library with six diversified CDRs was constructed by polymerase chain reaction assembly of overlapping oligonucleotides. In order to maximize the functional diversity of the library, a ${\beta}$-lactamase selection strategy was employed in which the assembled scFv gene repertoire was fused to the 5'-end of the ${\beta}$-lactamase gene, and in-frame scFv clones were enriched by carbenicillin selection. A final library with an estimated total diversity of $7.6{\times}10^9$, greater than 70% functional diversity, and diversification of all six CDRs was obtained after insertion of fully randomized CDR-H3 sequences into this proofread repertoire. The performance of the library was validated using a number of target antigens, against which multiple unique scFv sequences with dissociation constants in the nanomolar range were isolated.

• Journal of Intelligence and Information Systems
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• v.6 no.1
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• pp.73-82
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• 2000

This study examined the characteristicso f the knowledge discovery and data mining algorithms to demonstrate how they can be used to predict health outcomes and provide policy information for hypertension management using the Korea Medical Insurance Corporation database. Specifically this study validated the predictive power of data mining algorithms by comparing the performance of logistic regression and two decision tree algorithms CHAID (Chi-squared Automatic Interaction Detection) and C5.0 (a variant of C4.5) since logistic regression has assumed a major position in the healthcare field as a method for predicting or classifying health outcomes based on the specific characteristics of each individual case. This comparison was performed using the test set of 4,588 beneficiaries and the training set of 13,689 beneficiaries that were used to develop the models. On the contrary to the previous study CHAID algorithm performed better than logistic regression in predicting hypertension but C5.0 had the lowest predictive power. In addition CHAID algorithm and association rule also provided the segment characteristics for the risk factors that may be used in developing hypertension management programs. This showed that data mining approach can be a useful analytic tool for predicting and classifying health outcomes data.