• The Korean Journal of Physiology
• /
• 제4권2호
• /
• pp.19-24
• /
• 1970

Since the discovery of the muscle spindle by Hassall (1831), an intensive studies of its anatomical and physiological characteristics had been undertaken. Recent morphological studies of Boyd (1962) demonstrated that the muscle spindles have two different intrafusal muscle fibers, nuclear bag and nuclear chain fiber, and these intrafusal fibers are under independent motor innervation by ${\gamma}_1$ and ${\gamma}_2$ motor neurone. Neurophysiological studies of Hunt and Kuffler (1951) showed regulatory effect of ${\gamma}$ motor neurone upon the excitability of the spindle afferents. Harvey and Mathews (1961) observed the dynamic and static characteristics of the two different spindle afferents, the primary and secondary ending. Furthermore, Mathews (1962) postulated the functional existance of two kind of ${\gamma}$ motor neurones, namely, the dynamic and static fusimotor fiber. Recent report of Kim and Partridge(1969) pointed out that the descending vestibular signals had increased the slope of the length-tension relationship in stretch reflex; Kim (1967) demonstrated that the descending vestibular impulses act upon the stretch reflex loop through the ${\gamma}$ motor pathway. These experimental evidences from the morphological and neurophysiological studies on the muscle spindles support the concept that the stretch reflex action of the skeletal muscle operates as a negative feedback control system. The author had discussed the way by which the f system participates in the control of stretch relfex feed back system. that was taken for a prototype of posture and movement.

• 소성∙가공
• /
• 제9권4호
• /
• pp.339-347
• /
• 2000

For the successful forming of tailored blank, it is important to control the deformation of the stretch flange mode, which is strong1y dependent upon the location of weld line and blank shape. In order to investigate the effects of tailored blank design factors on the stretch flange forming, we made the model die which can simulate stretch flange mode. Taguchi method was employed to analyze the sensitivity of blank design factors for the forming of tailored blank. From the results of experiment S/N ratios were calculated and using Variance Analysis, significance of parameters and optimal condition of each factors were extracted. Based on these analyses, the weld line height and the strength ratio and the arc center height were selected as effective parameter. The analysed result was practically applied for Side outer panel stamping process.

• 한국의류산업학회지
• /
• 제2권2호
• /
• pp.150-158
• /
• 2000

This study investigated mechanical properties, drape coefficients and node indices of stretch fabrics. We applied mechanical properties to exhibited tailorability control in HESC and evaluated making-up. The mechanical properties such as tensile, bending, shearing, compression, surface characteristic values, thickness and weight were measured by the KES-F system and drape coefficient by drape tester. The summarized results of this study were as follows; First, stretch fabrics, almost, shown high stretch in weft inserted polyurethane yarn fabric and had a ${\pm}2{\sigma}$(sigma) range of shearing, compression, surface and thickness, except bending and weight, as compared with Japanese women's thin dress fabrics. Second, bending had a positive correlation in stiffness, anti-drape and flexibility & softness. Shearing had a negative correlation in crispness and scroop. Surface properties had a high contribution in fullness & softness. Third, The drape coefficient was found by measuring the mechanical properties according to the obtained regression equation. Forth, many problems are expected in overfeed and cutting operations in sewing process. In the decision of the good external appearance using TVA, only 26 of 55 samples are included in the range of the good external appearance. Fifth, in the regard of the result for sewing control, warp values are not necessary to control in the all kind of items. But weft value in the RT and EM are out of non-control zone. So we need a special management during sewing process.

• ETRI Journal
• /
• 제26권6호
• /
• pp.597-604
• /
• 2004

In stereoscopic television, there is a trade-off between visual comfort and 3-dimensional (3D) impact with respect to the baseline-stretch of a 3DTV camera. It is necessary to adjust the baseline-stretch at an appropriate the distance depending on the contents of a scene if we want to obtain a subjectively optimal quality of an image. However, it is very hard to obtain a small baseline-stretch using commercially available cameras of broadcasting quality where the sizes of the lens and CCD module are large. In order to overcome this limitation, we attempt to freely control the baseline-stretch of a stereoscopic camera by synthesizing the virtual views at the desired location of interval between two cameras. This proposed technique is based on the stereo matching and view synthesis techniques. We first obtain a dense disparity map using a hierarchical stereo matching with the edge-adaptive multiple shifted windows. Then, we synthesize the virtual views using the disparity map. Simulation results with various stereoscopic images demonstrate the effectiveness of the proposed technique.

• Structural Engineering and Mechanics
• /
• 제46권6호
• /
• pp.843-852
• /
• 2013

This paper presents results of the effect of different bolt tightening sequences and methods on the performance of gasketed bolted flange joint using nonlinear finite element analysis. Bolt preload scatter due to elastic interactions, flange stress variation and bolt bending due to flange rotation and gasket contact stress variation is difficult to eliminate in torque control method i.e. tightening one bolt at a time. Although stretch control method (tightening more than one bolt at time) eradicates the bolt preload scatter, flange stress variation is relatively high. Flange joint's performance is compared to establish relative merits and demerits of both the methods and different bolt tightening sequences.

• 대한치과교정학회지
• /
• 제42권2호
• /
• pp.64-72
• /
• 2012

Objective: The aims of this study were to examine whether a passive stretch stimulus by means of a functional appliance induces changes in the fiber composition of masticatory muscles and whether these changes are similar to the changes in stretched limb muscle fibers by using RT-PCR, western blot, and immunohistochemical assays. Methods: Five male New Zealand White rabbits were fitted with a prefabricated inclined plane on the maxillary central incisors to force the mandible forward (- 2 mm) and downward (- 4 mm). Further, 1 hind limb was extended and constrained with a cast so that the extensor digitorum longus (EDL) was stretched when the animal used the limb. The animals were sacrificed aft er 1 week and the masseter, lateral pterygoid, and EDL were processed and compared with those from control animals (n = 3). Results: The stretched EDL had a significantly higher percentage of slow fibers, whereas the stretched masticatory muscles did not show changes in the composition of the major contractile proteins aft er 7 days. Conclusions: The transition of fiber phenotypes in response to a stretch stimulus may take longer in the masticatory muscles than in the limb muscles.

• 대한의생명과학회지
• /
• 제11권1호
• /
• pp.23-29
• /
• 2005

Molecular imaging with targeted contrast agents enables tissues to be distinguished by detecting specific cell-surface receptors. In the present study, a ligand-targeted acoustic nanoparticle system is used to identify angioplasty-induced expression of tissue factor by smooth muscle cell within carotid arteries. Pig carotid arteries were overstretched with balloon catheters, treated with tissue factor-targeted or a control nanoparticle system, and imaged with intravascular ultrasound before and after treatment. Tissue factor-targeted emulsion bound and increased the echogenicity and gray-scale levels of overstretched smooth muscle cell within the tunica media, versus no change in contralateral control arteries. Expression of stretch-induced tissue factor in carotid artery media was confirmed by immunohistochemistry. The potential for abnormal thrombogenicity of balloon-injured arteries, as reflected by smooth muscle expression of tissue factor, was imaged using a novel, targeted, nanoparticulate ultrasonic contrast agent.

• Asian-Australasian Journal of Animal Sciences
• /
• 제9권2호
• /
• pp.171-174
• /
• 1996

Muscle protein synthesis in vitro was measured in chicks fed low-protein(10% CP) and control(20% CP) diets. Right leg muscles (M. gastrocnemius) were mounted on a support made of stainless steel to stretch in constant tension, whereas left leg muscles were unmounted. Both leg muscles were incubated in Dulbecco's modified Eagle's medium including L-[$4-^3H$] phenylalanine for 60 min to measure in vitro protein synthesis. There was no significant difference in fractional synthesis rate(FSR) of muscle protein between both dietary protein levels, whereas FSR with stretch in constant tension was significantly higher than that without constant tension due to an increase in the absolute synthesis rate(ASR) per unit RNA(the efficiency of RNA to synthesize protein). The ASR of muscle protein in chicks fed the control diet was significantly higher than that in the low-protein diet group.

• PNF and Movement
• /
• 제5권1호
• /
• pp.29-35
• /
• 2007

Purpose : The purpose of this study was investigated to find the approach in the PNF and TC for frail elder Method : This is a literature study with books, articles, seminal note and books for PNF and TC international course. Result : Neural mechanisms contribute significantly to the gains that occur in the range of motion about a joint with stretching exercises. The participation in a stretch-training program decreases tonic reflex activity and increases flexibility and decreases in force production and muscle activation. Also the stretching-induced decreases may be due to a central nervous system inhibitory mechanism. PNF stretch techniques can increase ROM in older adults. These results may differ from those of studies performed with younger populations because of age-related physiologic changes. TC exercise improves balance control and muscle strength and were associated with reorganized lower extremity neuromuscular patterns. Conclusions : The stretch training program of the PNF and TC contribute to increase the balance and coordination for frail elder. Therefore, The frail elder prevent falling. Further study, The PNF and TC be introduced as the new therapeutic intervention for frail elder.

• The Journal of Korean Physical Therapy
• /
• 제22권5호
• /
• pp.1-8
• /
• 2010

Purpose: This study aimed to provide a scientific basis for effects of the push-up plus exercise program on scapular position and on muscle activity in individuals with rounded shoulder posture (RSP). Methods: The supine method was applied to 46 potential subjects, of which 30 with RSP were selected. Subjects with RSP were divided into two groups: a gender push-up plus group as the experimental group a pectoralis minor self.stretch group as the control group. RSP data after 4 weeks of each intervention were obtained and analyzed to measure the activities of the 3 muscles. Results: The two groups differed significantly with regard to EMG changes in the serratus anterior (p<0.05). The EMG results indicated a significant reduction in the activity of the upper trapezius in the experimental group (p<0.05). EMG results indicated a significant increase in the activity of the serratus anterior after the intervention (p<0.05). EMG results of the subjects in the control group indicated that the activity of the upper trapezius significantly decreased (p<0.05). The RSP values of the subjects in both groups were significantly decreased (p<0.00). Conclusion: An improvement in the strength of the serratus anterior, and in the stretch effectiveness of the pectoralis minor, as well as changes in the scapular position were observed after 4 weeks of push-up plus exercise by the subjects.