• Clinical and Experimental Reproductive Medicine
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• v.9 no.1_2
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• pp.29-41
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• 1982

This retrospective clinical study was done based under the delivery records of 146 cases of twin pregnancies in Yonsei University, Severance Hospital and Wonju Christian Hospital from 1977 through 1980 with particular interest in the second twins. Clinical factors, Apgar scores related to neonatal prognosis, and perinatal mortality rate were statistically analyzed and the following results were obtained. The mean - birthweight for A (first) twins was 2,377 grams and for B (second) twins 2,296 grams. In comparison of the percentage of low-birth-weight (less than 2,500 grams) infants, there were more small B twins, but the difference was statistically not significant. Because there were no significant statistical differences in birth weight-grouping between A and B twins, they could be compared with the comprehensive Apgar scores, but this method was also shown to be statistically not significant. In comparison of the percentage of breech deliveries in A and B twins, the percentage was more than three times in B twin (A twin, 7.5 per cent; B twin, 24.0 per cent), and the difference was statistically very significant (p < 0.0005). There were no significant statistical differences between the Apgar scores of A and B twins in reference to the manner of delivery. According to the manner of delivery of B twins, spontaneous vertex delivery and total breech extraction revealed higher infant mortality rate than others. B twins presented by the vertex in 88 cases (61.0 per cent), by the breech in 55 cases (37.0 per cent), and by the shoulder in 3 cases (2.0 per cent). And this therefore disclosed no significant statistical differences in Apgar scores in relation to the presentation. The duration of labor appeared to have no clear correlation with the Apgar scores and the perinatal mortality of A and B twins. The delivery interval between A and B twins was 11.9 minutes on an. averge, varying from 3 to 65 minutes. The length of this interval was not found to have any significant effect on the Apgar scores and the perinatal mortality rate of B twin.

• Advances in pediatric surgery
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• v.15 no.2
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• pp.157-160
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• 2009

Although the incidence of esophageal atresia (EA) is higher in twins than in singletons by two to three times, EA usually affects only one member of twins. We report one pair of twins concordant for EA. A 31-year-old healthy woman bore monozygotic female twins at 36 weeks of gestation. They weighed 2,216 and 2,480 g, respectively. They had EA with distal tracheoesophageal fistula and underwent primary esophageal anastomosis on the birth day and the $2^{nd}$ day of life, respectively. Twin A also had suspicious antral obstruction and pyloroplasty was done simultaneously with esophageal repair. She needed antral web excision for continued gastric stasis one month after $1^{st}$ operation and three balloon dilatations of the esophagus. Twin B recovered uneventfully.

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.255-261
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• 1988

Conjoined twinning is a rare congenital malformation, accounting for 1% of monozygotic twins. Conjoined twins result if twining is initiated after the embryonic disc and rudimentary amnionic sac have been formed and if division of the embryonic disc is incomplete. Recently we experienced a case of conjoined twins, dicephalus dipus dibrachius, who had died at 3 hours of life, and performed autopsy. Autopsy revealed a total duplication of the heads, spines up to sacrum, small bowels, thymus and lungs. Two hearts existed within a common pericardium.

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.601-610
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• 2017

Purpose: Authors observe the digital twin enabled smart factory and/or digital manufacturing processes where Industry 4.0 technologies and quality management principles intersect. In this regard, this study reviews existing research regarding digital twins from the perspective of quality management. Methods: Initially, attention was given to how digital twins are manifested in the Industry 4.0 environment. Then, authors identify quality management elements amongst digital twin models, to align the concept of quality with the functional purpose of digital twins. After introducing specific examples of quality management tools applied to digital twins, the authors extend the domain of quality management into the analysis of multimedia format quality data obtained through machine vision. Results: Inspired by cases on the quality management application to digital twins, the authors suggest a framework for Industry 4.0 quality management. The envisioned suggested framework encompasses 4 dimensions, namely, 4M&1E, an application time window, new methodologies, and enabling technologies. Conclusion: Finally, the authors unfold the emerging trend of digital twin enabled smart factories, while emphasizing the necessity of quality management in conjunction with the introduction of digital twins.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.84-97
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• 2021

Digital twins are one of the promising digital technologies used to facilitate digital transformation. Therefore, it needs to continually be developed remain relevant in industry and academia. Consolidation of research is required to create a common understanding of the topic and to ensure that future research is built upon a solid foundation. Based on a bibliometric review and a thematic analysis of 217 publications on digital twins from the past two decades, this paper creates and analyzes a visual knowledge map and proposes areas for further research. To comprehensively analyze the development trends and research trends of digital twins, we performed statistical analysis of the relevant literature on digital twins within the core collection database of Web of Science. Through our research, we have shown that the current situation, trends, and hotspots of digital twin research were analyzed via CiteSpace. This study demonstrates that research on digital twins is rapidly growing in popularity, that the output of the research depends largely on the core group of authors conducting it, and that digital twins warrant cross-domain and cross-disciplinary research pathways.

• Childhood Kidney Diseases
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• v.25 no.1
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• pp.35-39
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• 2021

Bartter syndrome is an autosomal recessive hypokalemic salt-losing tubulopathy, and classic Bartter syndrome is associated with mutations in the CLCNKB gene. While chronic hypokalemia is known to induce renal cyst formation in different renal diseases, renal cyst formation in Bartter syndrome is rarely reported. Russian six-year-old identical male twins were referred to our hospital for the evaluation of renal cysts, which were incidentally detected on abdominal sonography due to diarrhea. Both twins had shown symptoms of polydipsia, polyuria, and nocturia since they were one year olds. Vital signs including blood pressure were normal in both twins. Renal sonography revealed nephromegaly, increased echogenicity of renal cortex, and various sized multiple cysts in both kidneys for both twins. Laboratory findings included hyponatremia, hypokalemia, hypochloremia, and metabolic alkalosis. Bartter syndrome with renal cysts were suspected. Genetic analysis for both twins confirmed a homozygous c.1614delC deletion on exon 15 of the CLCNKB gene, which was confirmed as a previously unreported variant to the best of our knowledge. They were managed with potassium chloride, nonsteroidal anti-inflammatory drugs, and angiotensin-converting-enzyme inhibitors. Metabolic alkalosis, hypokalemia, hypochloremia, and polyuria partially improved during the short course of treatment. This is the first report of a homozygous mutation in the CLCNKB gene in an identical twin, presenting with renal cysts.

• Neonatal Medicine
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• v.18 no.2
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• pp.197-203
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• 2011

Purpose: The purpose of this study is to compare perinatal outcomes between in vitro fertilization (IVF) twins and naturally conceived twins born to women aged 35 years or older and to provide basic information for taking care of IVF twins born to women aged 35 years or older. Methods: We reviewed the records of perinatal and neonatal outcomes in 288 IVF twins and 220 naturally conceived twins born to women aged 35 years or older between January 2001 and December 2010 at CHA Bundang Medical Center. Results: No difference was observed in the maternal ages of mothers giving birth to IVF twins and those giving birth to naturally conceived twins. Gestational ages and birth weights of IVF twins were not different from those of naturally conceived twins. Various perinatal outcomes, including gestational diabetes mellitus, pregnancy-induced hypertension, placenta previa, premature amniotic membrane rupture, and need for a Cesarean section did not differ between the 2 groups. However, the 1-min and 5-min Apgar scores (P=0.019 and P=0.045, respectively) were different between the 2 groups. The incidence of early-onset sepsis was lower in the IVF twins than in the naturally conceived twins (P=0.02). However, the 2 groups did not show any difference in the incidence of respiratory distress syndrome, bronchopulmonary dysplasia, patent ductus arteriosus, necrotizing enterocolitis, intraventricular hemorrhage, and other congenital anomalies. Conclusion: The perinatal outcomes in IVF twins born to women aged 35 years or older were not significantly different from those of naturally conceived twins.

• Economic and Environmental Geology
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• v.40 no.4
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• pp.461-471
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• 2007

A temperature of deformation and the state and direction of paleostress at that time when twins in calcite grains had been produced were observed, using analysis of calcite twins as indicators of paleostress history. The study was performed with the target of carbonate rocks distributed randomly small size in the southern area of south Korea. Considering the appearance of twins (thin or thick straight twins with one or two twin sets), average twin strain (1.235-7.453%), thickness ($0.77-1.94{\mu}m$) and intensity (25.26-41.99 twins/mm) from the results of calculated calcite twins, it is estimated that calcite twins were produced under temperatures lower than approximately $150-200^{\circ}C$. In the magnitudes and directions of principal strains, the maximum shortening strain axis ($e_3\leftrightarrow{\sigma}_1$) is approximately N-S direction in the GS-1 area in the southern Gyeongsang Basin as well as in the BS-1 area in the southern Yongnam Massif, whereas E-W direction in the NR-1 area in the southwestern Ogcheon Fold Belt. In case of the maximum extension strain axis ($e_1\leftrightarrow{\sigma}_3$), it is oriented in NW-SE and NE-SW directions in the GS-1 and BS-1 area, respectively, and in N-S direction in the NR-1 area. That is, it is suggested that the paleostress which produced the calcite twins may be applied at least more than two times in the study area.

• Korean Journal of Childcare and Education
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• v.9 no.6
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• pp.267-288
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• 2013

The purpose of this study was to examine the child-rearing difficulties of mothers with twins in an effort to discuss how to lend assistance to these mothers, as the birth of twins has been on the rise. The participants in this study were six mothers who resided in the city of P and raised infant twins. They were interviewed twice in depth from December, 2012, to July, 2013. The findings of the study were as follows: First, as for the difficulties of their children perceived by the mothers, their children had to share everything, no matter if it was good or bad, and they were confronted with environmental constraints. In addition, they were fragile from the moment they were born. Second, concerning the self-perceived child-rearing difficulties of the mothers, they had no time to take care of themselves at all and felt lonely all the time. And they were under pressure due to financial burden. In order to help these mothers and their children to tide over their difficulties, there should be a change in the way people in general look at twins, and the establishment of emotional and financial support systems is required. The findings of the study are expected to provide some information on how to offer full-fledged support for mothers with twins.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.6
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• pp.1058-1059
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• 1997