• Polymer(Korea)
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• v.28 no.5
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• pp.433-443
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• 2004

The membranes of the blends of chitosan and polycaprolactarn (PA6) were prepared in formic acid. FT-IR data revealed that hydrogen bonding between amide and hydroxyl groups of chitosan and PA6, respectively, was formed. Thermogravimetric analysis demonstrated that the blend samples contain water. DMA results showed that the dissipation of water in the samples significantly reduced the storage modulus (E'). The mechanical loss tangent (tan $\delta$) data of the blend samples showed the $\beta$d loss peak around $0^{\circ}C$. The blend samples were completely dried in a vacuum and then exposed to high moisture to absorb water which would cause, so called, w-bridges between the molecules. The E' data of these regained samples increased abnormally and additional loss peak appeared on the shoulder of the peak around $50^{\circ}C$. Under dry condition, the samples with a blend ratio of 40/60 for chitosan/PA6 displayed a better miscibility between two components.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.19 no.1
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• pp.20-28
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• 2016

Purpose: Foreign body (FB) ingestion is common in children, and button battery (BB) ingestion has been increasing in recent years. This study was to identify factors related to outcomes of FB ingestion, particularly BBs in the stomach. We evaluated whether the current recommendations are appropriate and aimed to suggest indications for endoscopic removal of BB in the stomach in young children. Methods: We investigated patient age, shape, size, location of FBs, spontaneous passage time and resulting complications among 76 children. We observed types, size, location of BB and outcomes, and analyzed their associations with complications. Results: Coins and BB were the two most common FBs. Their shapes and sizes were not associated with the spontaneous passage time. Size, spontaneous passage time, and age were also not associated with any specific complications. For BB ingestion, all 5 cases with lithium batteries (${\geq}1.5cm$, 3 V) presented moderate to major complications in the esophagus and stomach without any symptoms, even when the batteries were in the stomach and beyond the duodenum, while no complications were noted in 7 cases with alkaline batteries (<1.5 cm, 1.5 V) (p=0.001). All endoscopies were conducted within 24 hours after ingestion. Conclusion: The type and voltage of the battery should be considered when determining whether endoscopy is required to remove a BB in the stomach. For lithium battery ingestion in young children, urgent endoscopic removal might be important in order to prevent complications, even if the child is asymptomatic and the battery is smaller than 2 cm.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.203-203
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• 2016

The linkage between climate change and water security, i.e., the response of water resource to the future climate change, have been of great concern to both scientific community and policy makers. In this study, the impact of future climate on water resources in Yellow River Basin in North of China has been investigated using the Coupled Land surface and Hydrology Model System (CLHMS) and IPCC AR5 projected future climate change in the basin. Firstly, the performances of 14 IPCC AR5 models in reproducing the observed precipitation and temperature in China, especially in North of China, have been evaluated, and it's suggested most climate models do show systematic bias compared with the observation, however, CNRM-CM5、HadCM5 and IPSL-CM5 model are generally the best models among those 14 models. Taking the daily projection results from the CNRM-CM5, along with the bias-correction technique, the response of water resources in Yellow river basin to the future climate change in different emission scenarios have been investigated. All the simulation results indicate a reduction in water resources. The current situation of water shortage since 1980s will keep continue, the water resources reduction varies between 28 and 23% for RCP 2.6 and 4.5 scenarios. RCP 8.5 scenario simulation shows a decrease of water resources in the early and mid 21th century, but after 2080, with the increase of rainfall, the extreme flood events tends to increase.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.23-28
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• 2021

This research emphasized that the importance of ERG elements such as existence needs, relatedness needs, and growth needs. Moreover, it focused on verifying the effects of these three elements on organizational attachment through person job fit. In addition, the mediating role of person job fit was clearly identified as a key variable that can lead to organizational attachment. To verify this, an empirical analysis was conducted on workers engaged in state-owned company, service, manufacturing, and distribution industries in Korea. Through empirical analysis, it was found that all three elements of ERG improve person job fit. Furthermore, person job fit was found to increase the level of organizational attachment. Thus, it was found that person job fit played a partial mediating role in the relationship between the three elements of ERG and organizational attachment. This research also identified which element has the strongest influence on person job fit. Through these results, practical implications were presented and future research directions were discussed.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.23-28
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• 2021

This research analyzed the effects of entrepreneurship education and consulting programs on entrepreneurial intentions of pre-founders and verified the mediating effects of entrepreneurship competence in these influence relationships. This study conducted an empirical analysis of pre-founders in Gwangju and Jeonnam areas for empirical analysis. As a result of the actual analysis, entrepreneurship education and entrepreneurship consulting showed a positive (+) effect on entrepreneurship competency, and entrepreneurship education and entrepreneurship consulting showed a statistical significance as a parameter in the relationship between entrepreneurship will. The results of this study are meaningful in that it provides basic data for effective start-up education and consulting programs, thereby improving the entrepreneurial will of pre-founders and forming a good start-up culture. Finally, this study also presented limitations and future research directions.

• Journal of Korean Neurosurgical Society
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• v.64 no.3
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• pp.418-426
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• 2021

Objective : A role of diffusion-weighted imaging (DWI) in the diagnosis of cerebral venous thrombosis (CVT) is not well-understood. This study evaluates the effectiveness of DWI in the diagnosis of CVT. Methods : Literature search was conducted in electronic databases for the identification of studies which reported the outcomes of patients subjected to DWI for CVT diagnosis. Random-effects meta-analyses were performed to achieve overall estimates of important diagnostic efficiency indices including hyperintense signal rate, the sensitivity and specificity of DWI in diagnosing CVT, and the apparent diffusion coefficient (ADC) of DWI signal areas and surrounding tissue. Results : Nineteen studies (443 patients with 856 CVTs; age 40 years [95% confidence interval (CI), 33 to 43]; 28% males [95% CI, 18 to 38]; symptom onset to DWI time 4.6 days [95% CI, 2.3 to 6.9]) were included. Hyperintense signals on DWI were detected in 40% (95% CI, 26 to 55) of the cases. The sensitivity of DWI for detecting CVT was 22% (95% CI, 11 to 34) but specificity was 98% (95% CI, 95 to 100). ADC values were quite heterogenous in DWI signal areas. However, generally the ADC values were lower in DWI signal areas than in surrounding normal areas (mean difference-0.33×10-3 ㎟/s [95% CI, -0.44 to -0.23]; p<0.00001). Conclusion : DWI has a low sensitivity in detecting CVT and thus has a high risk of missing many CVT cases. However, because of its high specificity, it may have supporting and exploratory roles in CVT diagnosis.

• Advances in nano research
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• v.12 no.2
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• pp.197-212
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• 2022

The purpose of this study is to develop an automatic software system for bone age evaluation and to evaluate its accuracy in testing and feasibility in clinical practice. 20394 left-hand radiographs of healthy children (2-18 years old) were collected from China Skeletal Development Survey data of 1998 and China Skeletal Development Survey data of 2005. Three experienced radiologists and China-05 standard maker jointly evaluate the stages of bone development and the reference bone age was determined by consensus. 1020 from 20394 radiographs were picked randomly as test set and the remaining 19374 radiographs as training set and validation set. Accuracy of the automatic software system for bone age assessment is evaluated in test set and two clinical test sets. Compared with the reference standard, the automatic software system based on RUS-CHN for bone age assessment has a 0.04 years old mean difference, ±0.40 years old in 95% confidence interval by single reading, a 85.6% percentage agreement of ratings, a 93.7% bone age accuracy rate, 0.17 years old of MAD, 0.29 years old of RMS; Compared with the reference standard, the automatic software system based on TW3-C RUS has a 0.04 years old mean difference, a ±0.38 years old in 95% confidence interval by single reading, a 90.9% percentage agreement of ratings, a 93.2% bone age accuracy rate, a 0.16 years of MAD, and a 0.28 years of RMS. Automatic software system, AI-China-05 showed reliably accuracy in bone age estimation and steady determination in different clinical test sets.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.19-25
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• 2022

Purpose: This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT). Materials and Methods: This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA). Results: No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females. Conclusion: Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.

• Journal of dental hygiene science
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• v.22 no.4
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• pp.206-214
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• 2022

Background: This study analyzed the practice of dental medical dispute prevention rules of dental hygienists to present an improvement plan for improving perceived importance and practice and provide data for the development of effective medical dispute prevention programs. Methods: A self-administered questionnaire survey was conducted targeting dental hygienists who were providing assistance at dental hospitals and dental clinics in Seoul and Gyeonggi-do regions from March 22 to April 28, 2022. The questionnaire collected from 273 dental hygienists consisted of eight questions on general characteristics, 30 questions on medical dispute experience, and 14 questions on medical dispute prevention. Results: Complaints showed a high experience rate in 'Consultation & reservation', medical disputes in 'Patient handling (unkind) related', and 'Prosthesis installation and cement removal'. In both the importance and practice of medical dispute prevention rules, 'Preservation of medical records and other medical-related data' was high, and 'Management of patients on standby for a long time' was low in terms of practice. 'Lack of time' and 'Lack of manpower' were cited as reasons for not resolving dental treatment disputes. The importance of dental dispute prevention rules was found to be significant according to age and position, and it was also found to affect the level of practice. Conclusion: Seventy-six-point six percent of the respondents said that education on the prevention of medical disputes was necessary, although they lacked recognition of prevention rules compared to their perceptions and experiences. This study suggested specifying prevention rules in dental hygiene subjects and expanding education, improvement of dental treatment system, revise the law on the range of work to improve the recognition and practice of prevention rules.

• Archives of Craniofacial Surgery
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• v.24 no.6
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• pp.266-272
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• 2023

Background: In recent years, there has been an increase in reports of perioral vascular complications resulting from filler injections, such as necrosis of the lip or alar rim, occlusion, and in severe cases, blindness. Conversely, the use of perioral arterial flaps is becoming more prevalent in the treatment of cleft lips, cancer, and trauma. A thorough understanding of perioral arteries is essential to minimize complications and maximize the success of these flaps. However, the course of the facial artery (FA) in the perioral region remains incompletely understood. The aim of this study was to describe the variations of the FA in the perioral region. Methods: We dissected 52 embalmed and formaldehyde-fixed Vietnamese cadavers. We then studied the size and distribution of perioral arteries in 102 specimens. Results: The superior labial artery (SLA) was the most common branch, occurring in 87.25% of cadavers, followed by the inferior labial artery (ILA) at 78.43%. The SLA primarily originated above the mouth corner (cheilion), accounting for 91.01% of cases, and predominantly exhibited a tortuous course within the submucosa (78.65%). The ILA's branching pattern varied, but it was primarily located below the cheilion (91.25%). The ILA also followed a twisted path, generally within the submucosa. The ILA exhibited two patterns: the typical pattern, distributed at the vermilion border of the lower lip (8.82%), and the horizontal labiomental artery pattern, which ran horizontally in the middle of the lower lip area (69.61%). At their origin, the SLA and ILA had average external diameters of 1.29 mm and 1.28 mm, respectively. Conclusion: Numerous anatomical variations in the FA in the perioral region were found. A detailed anatomic description, suggested landmarks, and angiography before the procedure will be useful to help doctors avoid complications.