• 대한금속재료학회지
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• 제49권7호
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• pp.570-576
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• 2011

The shape of a dendrite tip has long been approximated by a paraboloid of revolution, but many attempts have been made as well to more accurately match the dendrite tip profile using other mathematical functions: power function, 4th order polynomial, and hyperbolic function. In the present work, dendrite tip shapes were matched by parabolic function. The differences between the dendrite tip shapes of pivalic acid(PVA)-ethanol(Eth) and succinonitrile(SCN)-salol systems, characterized by anisotropic and isotropic solid-liquid interfacial properties, respectively, were quantitatively treated using shape parameters. The PVA-Eth system showed a slightly higher Z/R value than the SCN-salol system, their Z/R values lying in the range 2-4. (Z is the distance from the tip beyond which the parabolic fit starts to deviate from the profile, and R the tip radius.) ${\lambda}_P$ is the distance from the tip beyond which side branching starts to appear, and is larger in the PVA-Eth system than the SCNsalol system. ${\lambda}_P$ is different for both sides of the 2-dimensional dendrite profile. The difference of ${\lambda}_P$ between both sides of the dendrite is larger for PVA-Eth system than for SCN-salol, implying that the dendrite of PVA-Eth is less symmetric than that of SCN-salol.

• 대한통합의학회지
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• 제8권4호
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• pp.241-251
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• 2020

Purpose : This study examined the effect of locomotive syndrome on stress index and lifestyle patterns among elderly Koreans aged 65 years and older, and analyzed its correlation with stress index and lifestyle patterns. The purpose of this study was to provide basic data for the management and prevention of locomotive syndrome in the elderly. Methods : Using the "25-Question Geriatric Locomotive Function Scale (GLFS-25)", the study evaluated locomotive syndrome in 123 elderly Koreans aged 65 years and older. Of them, 85 patients were assigned to the locomotive syndrome group and 38 patients were assigned to the normal group. The questionnaire measured and investigated the participants' stress index and lifestyle patterns. Statistical analysis was performed using SPSS 22.0 ver. Results : Results showed the locomotive syndrome group displayed a higher stress index than the normal group, with a statistically significant difference between the two groups. The group also scored lower in the lifestyle pattern survey than the normal group did, with a statistically significant difference in high-intensity work performance ratio and average daily performance time between them. The GLFS-25 score showed a significant positive correlation with the stress index and sitting and lying down time, and a significant negative correlation with medium-intensity working time, walking, and cycling time. Conclusion : In conclusion, Locomotive syndrome in elderly Koreans is closely related to stress and lifestyle patterns, especially high-intensity work. We recommend active prevention and management of locomotive syndrome and further research into the effects of various lifestyle factors on the illness.

• Investigative Magnetic Resonance Imaging
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• 제25권1호
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• pp.1-9
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• 2021

The aim of this study was to provide a new assessment of rotator cuff muscle activity. Eight male subjects (24.7 ± 3.2 years old,171.2 ± 9.8 cm tall, and weighing 63.8 ± 11.9 kg) performed the study exercises. The subjects performed 10 sets of the exercise while fixing the elbow at 90 degrees flexure and lying supine on a bed. One exercise set consisted of the subject performing external shoulder rotation 50 times using training equipment. Two imaging protocols were employed: (a) true fast imaging with steady precession (TrueFISP) at an acquisition time of 12 seconds and (b) multi-shot spin-echo echo-planar imaging (MSSE-EPI) at an acquisition time of 30 seconds for one echo. The main method of assessing rotator cuff muscle activity was functional T2 mapping using ultrafast imaging (fast-acquired muscle functional MRI [fast-mfMRI]). Fast-mfMRI enabled real-time imaging for the identification and evaluation of the degree of muscle activity induced by the exercise. Regions of interest were set at several places in the musculus subscapularis (sub), musculus supraspinatus (sup), musculus teres minor (ter), and deltoid muscle (del). We used the MR signal of the images and transverse relaxation time (T2) for comparison. Most of the TrueFISP signal was not changed by exercise and there was no significant difference from the resting values. Only the T2 in the musculus teres minor was increased after one set and the change were seen on the T2 images. Additionally, except for those after one and two sets, the changes in T2 were significant compared to those at rest (P < 0.01). We also demonstrated identify and visualize the extent to which muscles involved in muscle activity by exercise. In addition, we showed that muscle activity in a region such as a shoulder, which is susceptible to B0 inhomogeneity, could be easily detected using this technique.

• Journal of Korean Neurosurgical Society
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• 제64권3호
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• pp.386-405
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• 2021

Recent advancements in basic research on the process of secondary neurulation and increased clinical experience with caudal spinal anomalies with associated abnormalities in the surrounding and distal structures shed light on further understanding of the pathoembryogenesis of the lesions and led to the new classification of these dysraphic entities. We summarized the changing concepts of lesions developed from the disordered secondary neurulation shown during the last decade. In addition, we suggested our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase of development may cause corresponding lesions, such as failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neuro-cutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and regression failure spectrum of the medullary cord (thickened filum and filar cyst, low-lying conus, retained medullary cord, terminal myelocele and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association with the activity of caudal mesenchymal tissue in secondary neurulation involves a wider range of surrounding structures than in primary neurulation. Although the majority of the data are from animals, not from humans and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.

• 한국융합학회논문지
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• 제13권4호
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• pp.79-88
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• 2022

본 연구의 목적은 한국에서 COVID-19 유행 기간 동안 건강 행동 변화와 우울한 기분의 연관성을 평가하는 것이다. 한국 성인의 비례표본을 이용하여 인터넷 기반 단면 설문조사를 실시하였고, 로지스틱 회귀모형을 이용하여 연관성을 평가하였다. 그 결과, COVID-19 유행 기간 동안 앉거나 눕는 시간, 걷는 시간, 흡연 및 음주의 부정적인 변화는 우울한 기분으로의 변화와 관련이 있었다 [교차비(OR): 2.23(95% CI=1.77-2.81), 2.04(95% CI=1.63-2.56), 2.84(95% CI=1.51-5.36) 및 1.82(95% CI=1.26-2.63)]. COVID-19 유행기간 동안 긍정적인 건강 변화(활동 증가, 흡연 및 알코올 감소)를 증진시키기 위한 전략은 정신적 스트레스 경감에 도움이 될 수 있다.

• 대한물리의학회지
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• 제16권4호
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• pp.117-124
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• 2021

PURPOSE: This study examined the effect of muscle thickness of the deep cervical flexor muscle, muscle tonicity, and muscle fatigue of the superficial cervical flexor muscle by applying a functional latex pillow to patients with chronic cervical pain. METHODS: An experimental group using a functional latex pillow and a control group using a general pillow were assigned randomly to 30 people. Each pillow was applied in a comfortable lying position in the experimental group and control group. The deep cervical flexor muscle thickness was measured in the longus colli and longus capitus using ultrasonography. The muscle tonicity and muscle fatigue of the superficial cervical flexor muscle were measured separately in the sternocleidomastoid muscle using a myotonometer and electromyography. RESULTS: In the experimental group(functional latex pillow), the muscle tonicity of the superficial cervical flexor muscle like the sternocleidomastoid muscle was significantly lower than that of the control group (general pillow)(p < .01). CONCLUSION: This study suggests that the functional latex pillow may effectively reduce the muscle tonicity of the sternocleidomastoid muscle, which is the superficial cervical muscle, in patients with chronic cervical pain. On the other hand, it was not effective on the muscle thickness of the deep cervical flexor muscle and muscle fatigue of the superficial cervical flexor muscles.

• 한국콘텐츠학회논문지
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• 제22권10호
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• pp.676-690
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• 2022

이 연구의 목적은 20대 대선 후보 TV토론에서 '타당해 보이지만 그렇지 않은 논증'인 '오류(fallacies)'가 어떻게 나타나는지 탐구하고 그 함의를 제시하는 것이다. 이를 위해 20개 형식적·비형식적 오류 개념을 분석 유목으로 사용해 첫 번째와 마지막 토론회(240분 분량)의 후보 발언들을 질적으로 분석한다. 그 결과, 세 후보가 허수아비, 훈제 청어, 선결문제, 복합질문, 성급한 일반화, 피장파장 등 15종, 23건의 비형식적 오류를 범한 점이 발견된다. 후보들은 주로 자신의 이미지와 의제를 방어하고 상대의 이미지와 의제에 타격을 주려는 맥락에서 유사논증인 오류를 활용했다. 특히, 답하기 곤란한 의제에 직면할 때 여러 유형의 오류를 집중적으로 동원함으로써, 팩트체크에 걸리지 않고 거짓말을 하지 않고 실정법을 어기지 않고도 상황을 타개하려 했다. 선행연구는 오류 체계를 관념적으로 다뤄온 편이지만, 이 연구는 이 체계가 대선후보 TV토론 같은 중요한 정치 콘텐츠의 분석 및 해석 틀로 유용하다는 점을 보여준다. 또, 민주주의를 구현하는 핵심 장치인 정치토론에서 오류가 과사용 될 가능성에 대한 주의를 환기한다.

• Animal Bioscience
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• 제35권11호
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• pp.1800-1807
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• 2022

Objective: This study aimed to determine the effect of different cooling sessions (CSs) as a water conservation strategy on physiological, and production responses and welfare in Holstein Friesian cows during subtropical summer in Pakistan. Methods: Twenty-one cows were subjected to three CS in a completely randomized design. The treatments were: i) eleven hours continuous cooling with sprinklers - control (CNT), ii) four CS, and iii) two CS. The CNT represented the practices of the commercial dairy farms in the area, while the other CSs were used as water reduction strategies. Each CS lasted for 1 h with a 12 min cycle (3 min water on and 9 min off) with a sprinkler flow rate of 1.25 L/min. Results: The average temperature humidity index of the shed and the outside open area were 81.9 and 82.5, respectively. The results showed that both physiological responses were highest in the 2CS group followed by the CNT and the 4CS (p = 0.001). The CNT and 4CS groups had similar milk yield (p = 0.040). The 4CS group had more lying and eating times than the CNT and 2CS groups (p = 0.000). The cortisol level in the 2CS group was 2.0 and 2.2 ㎍/dL more than the CNT and the 4CS groups, respectively (p = 0.000). Conclusion: In conclusion, the 4CS was more efficient in cooling the cows and had better welfare, as it yielded similar milk yield, and better physiological responses than the CNT despite using 90% less water.

• Steel and Composite Structures
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• 제41권6호
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• pp.873-886
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• 2021

In this paper, an analytical solution for thermodynamic response of functionally graded (FG) sandwich plates resting on variable elastic foundation is performed by using a quasi 3D shear deformation plate theory. The displacement field used in the present study contains undetermined integral terms and involves only four unknown functions with including stretching effect. The FG sandwich plate is considered to be subject to a time harmonic sinusoidal temperature field across its thickness with any combined boundary conditions. Equations of motion are derived from Hamilton's principle. The numerical results are compared with the existing results of quasi-3D shear deformation theories and an excellent agreement is observed. Several numerical examples for fundamental frequency, deflection, stress and variable elastic foundation parameter's analysis of FG sandwich plates are presented and discussed considering different material gradients, layer thickness ratios, thickness-to-length ratios and boundary conditions. The results of the present study reveal that the nature of the elastic foundation, the boundary conditions and the thermodynamic loading affect the response of the FG plate especially in the case of a thick plate.

• 대한한의학방제학회지
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• 제30권4호
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• pp.281-291
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• 2022

Objectives : In this study, acute oral toxicity test of pomace Schisandra chinensis extracts was conducted in order to up-cycling to a high value-added industry using by-products discarded in the production process of Schisandra chinensis products and active ingredients such as dibenzocyclooctadiene lignans in Schisandra chinensis. Methods : Pomace Schisandra chinensis extracts were orally administered to SD-rats(female, n=3) without a control group according to the 'OECD guidelines'. After, mortality and clinical signs were observed, and the deceased animals were subjected to an autopsy. In addition, acute oral toxicity test was sequentially performed in step I (300 mg/kg), step II(300 mg/kg), step III(2,000 mg/kg), and step IV(2,000 mg/kg) according to the mortality. Results : There were no abnormalities caused by pomace Schisandra chinensis extracts in step I and step II. However, one animal each died in step III and step IV. In addition, clinical signs(salivation, decrease in food intake, prone position, decrease of locomotor activity, loss of locomotor activity, convulsion, hypothermia, lacrimation, staining around mouth, soiled perineal region, reddish urine, chromaturia, decrease of fecal volume, lying on side, blackish stool, no stool, compound-colored stool, refusal to feed, excitement, hypersensitivity, rigidity, dorsal position, etc.) were observed. But, no clinical signs were observed from 5th day, and experiment animals recovered completely. Conclusions : As a result of this study, pomace Schisandra chinensis extracts may exhibit acute toxicity at concentrations of 2,000 to 5,000 mg/kg, and the GHS classification was designated as 'Category 5'.