• The Korean Journal of Zoology
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• v.36 no.1
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• pp.84-96
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• 1993

한국산 도롱뇽(Hynobius leechii) 유생의 다리 발생 과정을 관찰하고 잠재적 돌연변이 유발물질인 제-methyl-N'-nitro-N-nitrosoguanidine(MNNG)과 잠재적 기형 유발물질인 retinol palmitate가 다리 발생에 미치는 영향을 알아보았다. 정상적인 개체에서 됫다리의 발생 단계는 외부와 내부의 형태적 특징을 기준으로 하여 7단계로 나누어 볼 수 있었으며 전연골세포의 밀집에 따른 골격형성은 다리 발생아의 근위부에서 시작하여 원위부로 진행됨을 확인할 수 있었다. 도롱뇽 유생을 MNNG(10 rpm)나 retinol palmitate(37.5 lpm)로 처리한 경우, 공통적으로 다리 원위부의 골격 형성이 억제되었으며, 특히 이러한 골격 형성 억제 현상은 처리시기가 이를수록 보다 심하게 나타났다. 이러한 결과는 발생을 저해하는 물질에 대한 미분화 상태의 세포들의 반응성이 발생과정 중 특정 단계에 국한됨을 시사하는 것으로 해석된다.

• Journal of Korean Neurosurgical Society
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• v.61 no.1
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• pp.28-34
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• 2018

Objective : Duplication of the vertebral artery (VA) is a rare vascular variant. This paper describes the anatomy and embryological development of duplicated VAs and reviews the clinical significance. Methods : Computed tomography (CT) angiography was performed in 3386 patients (1880 females, 1506 males) between March 2014 and November 2015. We defined duplication of the VA as a condition in which the VA has two origins that fused at different levels of the neck. Results : Ten of the 3386 patients (0.295%) who received CT angiography had a dual origin of the VA; three on the left side, and seven on the right side. In all seven with right dual origin of the VA, both limbs of the VA origin originated from the right subclavian artery. In all three patients with left dual origin of the VA, both limbs of the VA originated from the left subclavian artery and aortic arch. In all 10 patients, the medial limb of the duplicated VA was located posteriorly and medially to the common carotid artery (CCA) and anteriorly and laterally to the vertebral transverse foramen. In two patients, the medial limb of the duplicated VA was located in close proximity to the CCA. In another two patients, the medial limb of the duplicated VA was located in close proximity to the CCA, carotid bifurcation, and proximal internal carotid artery. Conclusion : Although duplication of the VA is asymptomatic in most patients, clinicians should consider this anomaly during diagnosis and treatment.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.3
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• pp.364-371
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• 2014

The purpose of this paper is to review recent developments in lower limb exoskeletons. The exoskeleton system is a human-robot cooperation system that enhances the performance of the wearer in various environments while the human operator is in charge of the position control, contextual perception, and motion signal generation through the robot's artificial intelligence. This system is in the form of a mechanical structure that is combined to the exterior of a human body to improve the muscular power of the wearer. This paper is followed by an overview of the development history of exoskeleton systems and their three main applications in military/industrial field, medical/rehabilitation field and social welfare field. Besides the key technologies in exoskeleton systems, the research is presented from several viewpoints of the exoskeleton mechanism, human-robot interface and human-robot cooperation control.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.3
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• pp.155-159
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• 1990

The growth of lean from nine wholesale cuts in relation to the total lean weight in carcass side were evaluated with three allometric equations for 18 Najdi male camels slaughtered at 8, 16 and 26 months of age. The allometric growth coefficients indicated that as the camels grew, weights of lean form brisket and flank cuts increased relatively more rapidly than the total lean in carcass side (${\beta}$ >1.1) and that weights of lean from wholesale shoulder and rump cuts increased relatively less rapidly (${\beta}$ <.9) than the total lean weight from carcass side. The growth coefficients for the lean in the thoracic limb and pelvic limb showed a dorsoventral rise in the growth impetus, with coefficients for the thoracic limb correspondingly higher than those of pelvic limb. The growth coefficients for the lean from shoulder, rib, flank and leg cuts increased (p<.01) with increased weight of total lean in carcass side, whereas it decreased with increased total lean weight in carcass side for the lean in neck, brisket, plate, loin and rump cuts. At a constant weight of total lean in carcass side, older camels had larger coefficients for lean in neck, brisket, rump, flank and leg cuts, but had smaller coefficients for lean in shoulder, rib, plate and loin cuts.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.9-13
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• 1997

The present study was designed to develop the functional electrical stimulation system in order to restore motor function of paralytic patients. We attempt to establish adequate stimulus parameters for the recovery of work unction in lower limb paralysis patients and to develop the electrical stimulation system, which is effective to protect foot drop in these patients. In our animal and human experiment, adequate stimulus condition for surface electrode on the lower limb were 0.2-0.3ms at the duration and 50 Hz, which contain 600Hz train pulse. This parameter has efficiently prevented the foot drop from lower limb paralysis, decreased muscle fatigue and induced powerful contraction of lower limb muscle.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.93-104
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• 2011

The purpose of this study was to investigate lower-limb joint torque of the two groups as it changed by somatosensory stimulation during the descent down three stairs of different heights and to describe the difference between the two groups, which are young people group and elderly people group. Subjects of each groups climbed down a stair at four stimulation conditions, which are non-stimulation, tibialis anterior tendon stimulation, achilles tendon stimulation, tibialis anterior - achilles tendon stimulation. Motion capture data were collected using 3D optoelectric motion tracking system that utilizes active infrared LEDs, near infrared sensor and force plate. The obtained motion capture data was used to build 3D computer simulation model. The results show that lower-limb joint torque of the two groups changed with somatosensory stimulation as they descended the stairs and the joint torque of the two groups differed from each other.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.359-366
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• 2023

In order to fully utilize the functions of the hand which is the end effector of the upper limb, other parts of the upper limb have to perform their own roles. Among them, the pronation and supination of the forearm, which allows the hand to rotate along the longitudinal direction of the forearm, play an important role in activities of daily living. In this paper, a soft wearable robot that assists the pronation and supination of the forearm for individuals with weakened or lost upper limb function is proposed. The wearable robot consists of an anchoring part with polymer (wrist strap, elbow strap), a tendon with a belt and wire, and an actuation module. It was developed based on the requirements with respect to friction of anchoring part, forearm compression, and friction of the tendon. It was confirmed that these requirements were satisfied through literature review and experiments. Since all components exist within the forearm when worn, it is expected to be easy to combine with the already developed soft wearable robots for the hand, wrist, elbow, and shoulder.

• Journal of the Ergonomics Society of Korea
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• v.28 no.1
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• pp.9-19
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• 2009

Repetitive movement, inadequate working posture, overuse of force, physical contact with sharp edge, vibration and temperature were well known risk factors of WMSDs (Work-related Musculoskeletal Disorders). Many researchers have investigated the relationship between inadequate working postures and incidences of WMSDs of the upper extremities, whereas relatively few researchers have tried to evaluate workload associated with the lower-body postures. The effects of lower-limb postures including various knee flexion angles on the subjective discomfort, heart rate and EMG of lower-limb muscles were investigated in this study. Thirty graduate students were asked to maintain thirteen different body postures, and heart rate and EMG data of five muscle groups (electro spine, biceps femoris, vastus medialis, gastrocnemius and tibialis anterior) from each posture were collected during fifteen minutes sustaining tasks. All participants were also asked to report their discomfort ratings of body parts. Results showed that high subjective discomfort ratings and heart rates were reported at the postures of knee angles of $60^{\circ}$ and $90^{\circ}$, whereas low discomfort ratings were founded at the postures of chair heights with 20cm, 40cm, and sitting with crossed legged. The change of median frequency for each muscle group during fifteen minutes tasks was investigated for each body posture to evaluate the relationship between muscle fatigue and body posture. It was found that the trends of changes of median frequency were different based on muscle group as well as lower-limb body posture from this study.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.217-226
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• 2010

The lower limb orthosis with a pneumatic rubber actuator, which is intended for the assistance and the enhancement of muscular activities of lower limbs was developed in this study. Compared to other knee extension assistive devices being developed by other researchers, our device is designed especially for the elderly people and intended only for slight assistance so that the subjects can keep their muscular strength. For the effectiveness of system, muscular activities of major muscles in lower limbs during sit-to-stand (STS) and squat motion were measured and analyzed. Subjects were performed the STS and squat motion with and without lower limb orthosis. We made comparison muscular activities between with and without lower limb orthosis. Lower limb orthosis was controlled using muscular stiffness force feedback that is controlled by muscular activities of the measured muscle from force sensor. For analysis of muscular activities, electromyography of the subjects was measured during STS and squat motion, and these were measured using MP 150(BIOPAC Systems, Inc.). Muscles of interest were rectus femoris(RF), vastus lateralis(VL), vastus medialis(VM) and vastus intermedius(VI) muscles in lower limbs of the right side. A biodex dynamometer was used to measure the maximal concentric isokinetic strength of the knee extensors of wearing and not wearing orthosis on right side. The test were performed using the concentric isokinetic mode of test with the velocity set at 60°/s for muscles around the knee joints. The experimental result showed that muscular activities in lower limbs wearing orthosis using muscular stiffness force of a vastus medialis muscle was reduced and knee extension torque of an knee joint wearing lower limb orthosis was increased. With this, we confirmed the effectiveness of the developed lower limb orthosis.

• Korean Journal of Health Education and Promotion
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• v.15 no.1
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• pp.179-194
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• 1998

This study focused on the body composition of Korean Basketball Players in Dual X -ray Absorptiometry. The principal subjects of this study were 10 Basketball Players who participated in the process of Dual Energy X -ray Absorptiometry at K.H. University Hospital for 8 months from Sept. 1. 1996 to April, 30. 1997. On the basis of the these measurements, the authors calculated physical indices and total fat percent. On the results of bone densitometry, the author analyzed body fat weight, body composition according to body position, bone mineral density and discerned the difference between the fatness which was calculated indirectly and which gained from the bone densitometry. 1. General Characteristics The mean age of the subjects was 20.4$\times$1.35 year. 2. Physical. Measurement The mean physical growth and development of the subjects were superior to standard value of the average Koreans 3. Body Fat by Physical Measurement Body surface area was 2.019$\times$0.111$m^2$, body volume was 74.4$\times$7.2$\ell$, body density was 1.041$\times$0.007$\ell$/kg, and body fat percent was 24.9$\times$2.9%. 4. Body Fat by Bone Densitometry Total body fat percent was 15.17$\times$2.19% and according to body position that of upper limb was 1.62%, that of lower limb was 5.55%, that of trunk was 7.06% and that of head was 1.05%. There was significant difference between the amounts of body fat from the methods used in this study; that from physical measurements and from bone densitometry method could be said most desirable. 5. Body composition According to Body Position Trunk was highest at 46.7%, lower limb was 36.0%, upper limb was 10.6%, and head was 6.7% in order. 6. Bone Mineral Content and Bone Density In bone mineral amount by body position, that of upper limb was 466.9$\times$46.4g, that of lower limb was 1,424.1$\times$154.0g, that of trunk was 1,343.0$\times$150.3g, and total bone mineral content was 3,786.8$\times$348.4g(4.78$\times$0.13%). Bone mineral density by body position, that of upper limb was 0.758$\times$0.072g/$\textrm{cm}^2$, that of lower limb was 1,342$\times$0.095g/$\textrm{cm}^2$, that of trunk was 1,169$\textrm{cm}^2$0.082g/$\textrm{cm}^2$, that of head was 1,742$\times$0.154g/$\textrm{cm}^2$ and total bone mineral density was 1,204$\times$0.077g/$\textrm{cm}^2$.