• Clinical and Experimental Reproductive Medicine
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• v.32 no.2
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• pp.165-170
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• 2005

Objective: The aim of present study was to evaluate the effectiveness of low-dose intravenous immunoglobulin (IVIg) therapy in women with recurrent spontaneous abortions (RSA) and elevated pre-conceptional peripheral blood CD56+Natural Killer (NK) cell percentage. Study Design: Retrospective case control study. Materials and Methods: Thirty three women with RSA and elevated pre-conceptional peripheral blood CD56+NK cell percentage who had received low-dose IVIg therapy (400 mg/kg per day, every 4 week, until 20 gestational weeks) were included in this study. Controls were nine women with RSA and elevated pre-conceptional peripheral blood CD56+ Natural Killer (NK) cell percentage who had not received IVIg therapy were included in this study. Medical records of study and control groups were retrospectively analyzed and we compared the successful pregnancy outcomes between two groups. Successful pregnancy outcome was defined as pregnancy ongoing beyond 25 gestational weeks. Results: Age, number of previous abortions, pre-conceptional CD56+NK cell percentage and type of RSA were not statistically different between two groups. Otherwise, twenty-five women who received IVIg therapy (25/33, 75.8%) but, only three women who had not received (3/9, 33.3%) had a successful pregnancy outcome and the rate difference between two groups was statistically significant. Conclusion: Based on our study, low-dose IVIg therapy have a effective role in treatment of RSA patients with elevated pre-conceptional peripheral blood CD56+ Natural Killer (NK) cell percentage, but more larger scaled prospective study is needed for available of conclusive evidence.

• Structural Engineering and Mechanics
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• v.50 no.5
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• pp.589-603
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• 2014

Expressions for determining the value of the impact force as reported in the literature and incorporated into code provisions are essentially quasi-static forces for emulating deflection. Quasi-static forces are not to be confused with contact force which is generated in the vicinity of the point of contact between the impactor and target, and contact force is responsible for damage featuring perforation and denting. The distinction between the two types of forces in the context of impact actions is not widely understood and few guidelines have been developed for their estimation. The value of the contact force can be many times higher than that of the quasi-static force and lasts for a matter of a few milli-seconds whereas the deflection of the target can evolve over a much longer time span. The stiffer the impactor the shorter the period of time to deliver the impulsive action onto the target and consequently the higher the peak value of the contact force. This phenomenon is not taken into account by any contemporary codified method of modelling impact actions which are mostly based on the considerations of momentum and energy principles. Computer software such as LS-DYNA has the capability of predicting contact force but the dynamic stiffness parameters of the impactor material which is required for input into the program has not been documented for debris materials. The alternative, direct, approach for an accurate evaluation of the damage potential of an impact scenario is by physical experimentation. However, it can be difficult to extrapolate observations from laboratory testings to behaviour in real scenarios when the underlying principles have not been established. Contact force is also difficult to measure. Thus, the amount of useful information that can be retrieved from isolated impact experiments to guide design and to quantify risk is very limited. In this paper, practical methods for estimating the amount of contact force that can be generated by the impact of a fallen debris object are introduced along with the governing principles. An experimental-calibration procedure forming part of the assessment procedure has also been verified.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.986-993
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• 2021

This study was aimed to investigate the improvement effects of kelp extract on the damaged hair by manufacturing hair quality improving formulation adding kelp extract and applying that in the damaged hair. With respect to the study materials, the formulation was manufactured with different strengths of kelp extract including 0, 2, 4, and 6 grams, adding perm base material. The manufactured formulation was applied to the decolored sample hair of Level 8 and its effects were measured and compared before and after its application. Tensile strength, absorbance using methylene blue, and gloss were measured as the tools to show the improvement effects of hair quality. To check the reliability of the results, statistical analysis was performed. Tensile strength showed to be increased in the Level 8 samples applied by the formulations containing 4- and 6-gram strength. Absorbance using methylene blue showed to be decreased in all the samples after the application, based on the absorbance results before and after the application. No difference was found in all the samples on the gloss. In conclusion, this study revealed that kelp extract could improve the damaged hair. Further studies are required to check the improvement effects on the damaged hair with multiple types of extracts and study methods.

• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.189-201
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• 2021

The art of dynamic images has experienced three development stages, including experimental films, recording art, and new media image. By introducing all kinds of new materials, new media to the art, and the art of dynamic images has created more freedom for art creation. With the development of digital information technology, dynamic image works have put forward an increasingly high requirement of visual art. The combination of dynamic images and visual illusion can give rise to different forms and expression methods, thus endowing artworks with more vigor. This paper provides an overview by sorting out the lineage and development of dynamic images in the background, as well as understanding the application and performance of contrasted visual illusion. Based on the understanding of the characteristics of visual illusion, we discuss the new characteristics of applying the theory of visual illusion to new media dynamic images in relation to the technical approach of dynamic images. Through the analysis of specific works of Telematic Vision, we search for its reasonable combination and find the appropriate technical means of implementation. We discuss how to use digital multimedia technology and spatial optical illusion to make the design more novel and impactful, and consider how the combination of digital dynamic image technology and visual illusion should be interpreted and applied.

• Composites Research
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• v.34 no.5
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• pp.296-304
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• 2021

This study presented the evaluation of the stamp forming process for L-shape CF/PEKK thermoplastic composite using the finite element model. The formability of three different trimming allowances has been examined for representative product geometry. The results showed that those manufactured by high trimming allowance showed more excellent formability in those areas. Moreover, the effects of the trimming allowances on the stress, thickness, wrinkle distributions of thermoplastic composites fabricated with the stamp forming process were evaluated. The comparison of the simulation and experimental results for the thickness and wrinkle distributions proved the accuracy of the stamp forming model. The crystallinity of the composite was performed by differential scanning calorimetry (DSC). The void content of the composite was evaluated by matrix digestion. Then, the fabricated structure was characterized and achieved high quality in crystallinity and void content. Consequently, the presented FEM modeling shows excellent potential for application in the aircraft product design process. This pragmatic approach could efficiently offer a valuable solution for the thermoplastic composite manufacturing field.

• Land and Housing Review
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• v.12 no.3
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• pp.67-78
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• 2021

After World War II, modular housing was developed as a means of quickly and efficiently meeting the housing supply demand. For the past 30 plus years, efforts have been made to improve modular housing in South Korea and to increase their competitiveness in the housing market. This study investigated modular houses based on a steel framed rahem structure which provides a flexible floor plan where walls are easily reconfigured to create rooms of various sizes and functions. Similar to the factory production methods used in the automotive industry, the modular housing industry can also benefit by standardizing such aspects as building components, manufacturing and construction methods, materials, process management, and floor plans. This study examined the feasibility of using a 3m × 3m module for developing various floor plans which are easy to produce and transport. Each 3m × 3m module can be configured to meet different living needs resulting in a complete home when multiple modules are connected. The module configurations can be varied to meet ground transportation and crane limitations. This study found that a 3m × 3m steel framed modular unit is a promising step towards providing residents with plans that meet their living preferences while improving and increasing the supply of modular houses.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.5
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• pp.147-157
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• 2019

In this study, mathematics education program was developed for the foreign students who entered the science and engineering college of Korea in order to improve their basic competency and to prevent dropouts. It is applied to 5 Chinese students, 4 male students and 1 female student. Three students are majoring in engineering college and two students are majoring in natural science college. Before applying the mathematics education program to foreign students, most students did not draw a graph of the 'irrational function' and the 'exponential function' and did not understand the concept of the 'limit' at all. However, after applying the mathematics program, all foreign students were able to draw graphs of the various function and the limit values were calculated accurately. Through the results of this study, the researcher proposes some of the following. When developing mathematics education programs for foreign students, it is very important to develop teaching materials suitable for their level. Textbook developers need to select and organize contents that are essential for learning in university mathematics and to present mathematical concepts and examples considering the Korean language level of foreign students. Moreover, it will be necessary to try to present mathematical terms commonly used in Korea in their native language or English.

• Journal of Korean Society of Spine Surgery
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• v.25 no.4
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• pp.180-184
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• 2018

Study Design: Case report Objectives: To document fistula formation between the disc and dura by an unrecognized dural tear after percutaneous endoscopic lumbar discectomy (PELD). Summary of Literature Review: The risk of durotomy is relatively low with PELD, but cases of unrecognized durotomies have been reported. An effective diagnostic tool for such situations has not yet been identified. Materials and Methods: A patient twice underwent transforaminal PELD under the diagnosis of a herniated lumbar disc at L4-5. She still complained of intractable pain and motor weakness around the left lower extremity at 6 months postoperatively. Magnetic resonance imaging showed no specific findings suggestive of violation of the nerve root. However, L5 and S1 nerve root injury was noted on electromyography. An exploratory operation was planned to characterize damage to the neural structures. Results: In the exploration, a dural tear was found at the previous operative site, along with a fistula between the disc and dura was also found at the dural tear site. The durotomy site was located on the ventrolateral side of the dura and measured approximately 5 mm. The durotomy site was repaired with Nylon 5-0 and adhesive sealants. The patient's preoperative symptoms diminished considerably. Conclusions: Fistula formation between the disc and dura can be caused by an unrecognized dural tear after PELD. Discography is a reliable diagnostic tool for fistulas formed by an unrecognized durotomy.

• Journal of Korean Society of Spine Surgery
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• v.25 no.4
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• pp.185-195
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• 2018

Study Design: Literature review. Objective: Ultrasound-guided injections are a common clinical treatment for lower lumbosacral pain that are usually performed before surgical treatment if conservative treatment fails. The aim of this article was to review ultrasound-guided injections in the lumbar and sacral spine. Summary of Literature Review: Ultrasound-guided injections, unlike conventional interventions using computed tomography or C-arm fluoroscopy, can be performed under simultaneous observation of muscles, ligaments, vessels, and nerves. Additionally, they have no radiation exposure and do not require a large space for the installation of equipment, so they are increasingly selected as an alternative method. Materials and Methods: We searched for and reviewed studies related to the use of ultrasound-guided injections in the lumbar and sacral spine. Results: In order to perform accurate ultrasound-guided injections, it is necessary to understand the patient's posture during the intervention, the relevant anatomy, and normal and abnormal ultrasonographic findings. Facet joint intra-articular injections, medial branch block, epidural block, selective nerve root block, and sacroiliac joint injections can be effectively performed under ultrasound guidance. Conclusions: Ultrasound-guided injections in the lumbar and sacral spine are an efficient method for treating lumbosacral pain.

• Journal of Korean Society of Spine Surgery
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• v.25 no.4
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• pp.169-174
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• 2018

Study Design: Case report. Objectives: We report a case of pure epidural cavernous hemangioma located at the thoracolumbar spine in a 53-year-old woman that mimicked a neurogenic tumor on magnetic resonance imaging (MRI). Summary of Literature Review: A pure spinal epidural cavernous hemangioma without bony involvement is a very rare lesion about which limited information is available in the literature. Materials and Methods: A 53-year-old woman visited our clinic for hypoesthesia with a tingling sensation in the left anterolateral thigh that had begun a month ago. No other neurologic symptoms or signs were present upon a neurologic examination. MRI from an outside hospital showed a $2.0{\times}0.5cm$ elongated mass at the T11-12 left neural foramen. The tumor was completely removed in piecemeal fashion. Results: The histopathologic examination revealed a cavernous hemangioma, which was the final diagnosis. The outcome was favorable in that only operation-related mild back pain remained, without any neurologic deficits, after a postoperative follow-up of 2 years and 3 months. No recurrence was observed on MRI at 2 years postoperatively. Conclusion: Pure epidural spinal cavernous hemangioma is very rare, and it is very difficult to differentiate from other epidural lesions. However, we believe that it should be included in the differential diagnosis of spinal epidural tumors due to its favorable prognosis.