• Physical Therapy Korea
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• v.8 no.1
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• pp.76-88
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• 2001

Back extension exercises have been used for rehabilitation of the injured low back, prevention of injury, and fitness training programs. However, excessive loading on low back can exacerbate existing structural weakness. The purpose of this study was to compare muscle activity of low back muscles during back extension exercises. Twenty healthy male subject s were evaluated. Electromyographic (EMG) activities of low back muscles at L1 and L5 level were recorded during seven different back extension exercises and two reference tasks by surface EMG and saved for data analysis. Reference tasks of lifting 20% and 40% of their body weight were included for comparison. The result were as follows: 1) Single-arm extension and single-leg extension exercises on quadruped position appeared to constitute a low-risk exercise for initial extensor strengthening. 2) When arm extension was combined with contralateral leg extension on quadruped position, EMG activities of low back muscles were increased. 3) EMG activity of low back muscles was highest during the trunk extension exercises on prone position. 4) EMG activities of low back muscles during arm and leg extension exercises on quadruped position were less than those of reference task of lifting 40% of their body weight. These result s have important implications for progressive back extensor muscle strengthening exercises in patients with back pain.

• Journal of Life Science
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• v.28 no.4
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• pp.421-428
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• 2018

Postprandial hyperglycemia plays an important role in the development of Type 2 Diabetes and diabetic complications. Controlling postprandial hyperglycemia is the most important factor for reducing the risks of diabetic complications in Type 2 diabetic patients. This study was designed to determine whether Portulaca oleracea L. extract suppresses the activation of carbohydrate-digesting enzymes, and lowers postprandial hyperglycemia in diabetic mice through streptozotocin. P. oleracea was extracted with either 80% ethanol (PEE) or water (PWE), and the extract solutions were concentrated. The ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibition assays were performed using the chromogenic method. Normal mice and STZ-induced diabetic mice were orally treated with PEE, PWE (300 mg/kg of body weight) or acarbose (100 mg/kg of body weight), with soluble starch (2 g/kg of body weight). The ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory effectiveness by PEE were markedly more effective than PWE, and both extracts indicated a higher effectiveness than the acarbose (positive control). The rise in postprandial blood glucose due to starch loading was markedly inhibited in the PEE group when compared to the control group in diabetic and normal mice. Furthermore, the area under the concentration-time curve values were markedly declined by the PEE injection in the diabetic group when compared to that exerted for the control group. These results demonstrate that P. oleracea extracts lower postprandial hyperglycemia by inhibiting carbohydrate-digesting enzymes, and that the ethanol extract is more efficacious than the water extract.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.723-736
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• 1992

Most degeneating diseases and back pains in the orthopaedic disease are originated from the unbalance of stress distribution in the low-lumbar spine. Therefore the stress analysis of lowerback is indispensible to the clinical diagnosis for the developing reason and the developing process of diseases. Therefore the same model materials as following are eveloped to analyze the stress distributions of lower-back by photoelastic experiment. The verterbral body and the process are molded from epoxy resin(the weight ratio of Araldite and hardner is 10 to 3), models are geometrically identical to them in vivo respectively and the ratio of their elastic modulus to that of model material is 1 to 10. It is assured that KE-1300 Silicon(E=0.8MPa), TSE-3562 Silicon(0.5MPa) and the composite silicon(3MPa) (the weight ratio of KE-1300 silicon and Jioreal : 10 to 4) are respectively effective as the model materials of ligament, musles and intervertevral disc which is essential to the movement of low-lumbar spine. All the elements associated with the movement of the low-lumbar spine are molded through the molding method developed in this research and assembled with the angles between the verterbra and the disc in the normal human lumbosacral spine. The stress distributions of the assembled model are analyzed by photoelastic experiment. It is certified by comparing the results of photoelastic experimebt with the clinical situations that the loading dveice and the loading conceptions used in this paper are effective.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.403-414
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• 2002

I. Purpose of Study Zea Mays L. has been known to be effective for improving periodontal health and Magnoliae cortex to have effective antibacterial and antimicrobial activity against periodontal pathogens. The purpose of this study was to examine the biologic effects of Zea Mays L. and Magnoliae cortex extract mixtures on healing of rat calvarial bone defects. II. Materials & Methods 8mm circular defects were prepared on rat calvaria during surgical procedures of 180 Sprague-Dawley rats. The ethanolic extracts of Magnoliae cortex and Zea Mays L. and these two natural extract 1:1 and 2:1 (Magnoliae: Zea Mays L.) ratio mixtures were oral administrated by oral zondes once a day at two different dose of 94.5mg/kg, 189mg/kg body weight. There are nine groups of rats in this study: control group (no sample loading), Magnoliae cortex extract loading groups (I,II)(94.5mg/kg,189mg/kg respectively), Zea Mays L. extract loading groups (I,II), M:Z(1:1) loading groups (I,II), M:Z(2:1) loading groups(I,II). Rats were sacrificed at 4 weeks and 6 weeks after surgery. New bone formations around calvarial defects were radiographically and histologically measured by computerassisted histomorphometry. Each data was statistically analyzed by One-way ANOVA test. III. Results There were statistical significances between negative control group and the other test groups on radiographical and histological quantitative assessments. Among test groups, mixture groups showed statistical significances, especially, M:Z (2:1) groups (I and II) were highly significant.(p<0.05) These results implicated that the mixture of Magnoliae and Zea Mays L. (2:1 mixing ratio) with 94.5mg/kg concentration might be highly effective on the wound healing of bony defected site and have potential possibilities as a useful drug to promote bone tissue regeneration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.451-455
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• 2020

This study evaluated acute toxicity of chlorine dioxide (ClO₂ ) to juveniles of black seabream Acanthopagrus schlegelii (19.4±2.3 g, 10.7±0.4 cm) and red seabream Pagrus major (74.9±8.2 g, 15.9±1.0 cm). Thirty juveniles for each species were exposed to target ClO₂ concentrations of 0, 0.05, 0.1, 0.125, 0.15, 0.2, 0.3, 0.4, and 0.5 mg/L in triplicate for eight days. Half lethal concentrations for 96 hours were found at 0.14 and 0.24 mg ClO₂/L for black seabream and red seabream, respectively. Red seabream larger than black seabream in body weight appears to be more resistance to chlorine dioxide. However, regardless of species or size, specific loading rates of chlorine dioxide to total fish weight (daily feeding amount of ClO₂/total fish weight) were similar, showing 1.3 and 1.1 g ClO₂/kg fish·day^-1 for black seabream and red seabream.

• Korean Journal of Applied Biomechanics
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• v.29 no.3
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• pp.173-183
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• 2019

Objective: The aim of this study was to investigate the correlation coefficients between anthropometric parameters of the foot and kinetic variables during running. Method: This study was conducted on 21 healthy young adults (age: $24.8{\pm}2.1yes$, height: $177.2{\pm}5.8cm$, body mass: $73.3{\pm}7.3kg$, foot length: $256.5{\pm}12.3mm$) with normal foot type and heel strike running. To measure the anthropometric parameters, radiographs were taken on the frontal and sagittal planes, and determined the length and width of each segment and the navicular height. Barefoot running was performed at a preferred velocity ($3.0{\pm}0.2m/s$) and a fixed velocity (4.0 m/s) on treadmill (Bertec, USA) in order to measure the kinetic variables. The vertical impact peak force, the vertical active peak force, the braking peak force, the propulsion peak force, the vertical force at mid-stance (vertical ground reaction when the foot is fully landed in mid-stance or at the point where the weight was uniformly distributed on the foot) and the impact loading rate were calculated. Pearson's correlation coefficient was used to investigate the relationship between anthropometric variables and kinetical variables. The significance level was set to ${\alpha}=.05$. Results: At the preferred velocity running, the runner with longer forefoot had lower active force (r=-.448, p=.041) than the runner with short forefoot. At the fixed velocity, as the navicular height increases, the vertical force at full landing moment increases (r= .671, p= .001) and as the rearfoot length increases, the impact loading rate decreases (r=- .469, p= .032). Conclusion: There was a statistically significant difference in the length of fore-foot and rearfoot, and navicular height. Therefore it was conclude that anthropometric properties need to be considered in the foot study. It was expected that the relationship between anthropometric parameters and kinetical variables of foot during running can be used as scientific criteria and data in various fields including performance, injury and equipment development.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.167-174
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• 2015

Purpose : The purpose of this study was to investigate the effects of loaded vertical jumps on the following vertical jumps and to find how long the transient effect of warm-ups would continue. Methods : Twelve healthy college male students, majoring in physical education, participated in this study voluntarily. They performed three sets of unloaded jumps (pre-jump, 5% post jump, and 10% post jump) and two sets of loaded jumps (5% and 10% loaded jumps) according to the counter-balanced order. At each set, three trials of maximal vertical jumps were performed by a 30 second interval between trials and a 3 minute break after warm-up jumps. Force platform and motion capturing system were used to record motions and ground reaction force. Results : Only 5% post-warm-up jumps ($48.29{\pm}2.06cm$) showed significant increase in the jump height compared with pre-warm-up jumps ($47.35{\pm}2.21cm$). The transient effects of loaded warm-ups disappeared 4 minutes after loaded jumps. Conclusion : Conclusively, a decent amount of loading (around 5% extra of body weight) during sport specific warm-ups would give a positive, transient effect on the performance of the vertical jump.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.1
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• pp.36-43
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• 2017

A drug infuser is a well-known device that is widely used in various areas of clinical practice. However, some materials used in the drug infuser have been developed for particular purposes and thus, their design characteristics have to be changed considerably. Especially, the implications of a new filler in the drug infuser have migrated to the areas of body corrections in plastic surgery. In this study, the design process of a drug infuser managing a large content volume has been studied from the perspective of structure safety. A new design of the drug infuser that uses a 10 cc filler with high viscosity is presented. Finite element analysis is used to confirm that the assembled drug infuser is safe enough to hold the required loading of 490 N. Furthermore, the final prototype of the drug infuser was successful in reducing the weight up to 400 g without compromising the safety.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.7
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• pp.73-80
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• 2005

Biped robot requires that an energy source and a control part should be installed on the body to realize active system. So, we choose the DC motor having high torque in compact size in this study. In the DC motor serve system, we choose power amplifier with analog configuration, developed the module combined the controller and the driver. We applied this module to robot actuator and studied the response characteristics in an action and a return. Main controller with serve system, loading PIC micro controller, can be load on the robot with light weight.

• Nutrition Research and Practice
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• v.4 no.3
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• pp.203-207
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• 2010

This study investigated the effects of Oligonol intake on cortisol, interleukin (IL)-$1{\beta}$, and IL-6 concentrations in the serum at rest and after physical exercise loading. Nineteen healthy sedentary male volunteers participated in this study. The physical characteristics of the subjects were: a mean height of $174.2{\pm}2.7$ cm, a mean weight of $74.8{\pm}3.6$ kg and a mean age of $22.8{\pm}1.3$ years. Each subject received 0.5 L water with Oligonol (100 mg/day) (n = 10) or a placebo (n = 9) daily for four weeks. The body composition, the white blood cell (WBC) and differential counts as well as the serum cortisol, IL-$1{\beta}$, and IL-6 concentrations were measured before and after Oligonol intake. The cortisol concentration and serum levels of IL-$1{\beta}$ and IL-6 after Oligonol intake were significantly decreased compared to before treatment (P < 0.01, respectively). In addition, the rate of increase of these factors after exercise was decreased compared to the placebo group. There was no change in the WBC and differential cell counts. These results suggest that oral Oligonol intake for four weeks had a significant effect on inhibition of inflammatory markers in healthy young men.