• The Korea Journal of Herbology
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• v.27 no.6
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• pp.71-76
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• 2012

Objectives : The purpose of this study was to evaluate the neuroprotective effect of Pueraria lobata extract on focal cerebral ischemia in mice. Methods : Focal cerebral ischemia was induced by occlusion of the right middle cerebral artery using the intraluminal filament model. ICR male mice underwent 90 minutes of middle cerebral artery occlusion (MCAo) followed by 24 hours of reperfusion. Mice were administered Pueraria lobata extract orally at the dose of 300mg/kg just prior to reperfusion. Rotarod test and balance beam test were practiced to assess sensory-motor function 23 hours after MCAo. In rotarod test, the latency to fall on the accelerating rotarod was recorded for 5 min. In balance beam test, the score was graded according to number of slips and latency to cross. The infarct volume was measured 24 hours after MCAo using 2% 2,3,5-triphenyltetrazolium chloride (TTC) staining. Results : Pueraria lobata extract treated group showed significant reduction in infarct volume by 27.3% compared to control group (p<0.05). In rotatod test, it also showed significant extension of latency time compared to control group ($67.82{\pm}15.08$ vs. $5.62{\pm}1.06$, p<0.001). In contrast to performance in rotarod test, that in balance beam test did not improve with Pueraria lobata extract treatment. Conclusions : We conclude that Pueraria lobata extract has a significant neuroprotective effect and reduces damage of sensory-motor function in MCAo model. These findings suggest that Pueraria lobata could be a potent neuroprotective agent.

• Korean Journal of Child Studies
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• v.23 no.1
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• pp.71-85
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• 2002

This study examined the effects of different interaction styles, that is, interaction with an object and interaction with an adult, on young children's cognitive level. Subjects were 150 5-year-old children. The task required children to predict the working of a mathematical balance beam. Seven cognitive levels were identified based on the logic of prediction. Data were analyzed by t-test, F-test, Duncan Test and Wilcoxon Matched-Pairs Test. Results showed that both interaction styles caused improvement in children's cognitive level, but when interaction with an adult was divided into two categories, i.e., interaction with the higher group and interaction with the lower group, the latter experienced decline in cognitive level. Regardless of sex, interactions within the Zone of Proximal Development and with the object were found to be effective methods for children's cognitive improvement.

• Imaging Science in Dentistry
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• v.54 no.2
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• pp.159-169
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• 2024

Purpose: The aim of this study was to evaluate the influence of different cone-beam computed tomography (CBCT) acquisition protocols on reducing the effective radiation dose while maintaining image quality. Materials and Methods: The effective dose emitted by a CBCT device was calculated using thermoluminescent dosimeters placed in a Rando Alderson phantom. Image quality was assessed by 3 experienced evaluators. The relationship between image quality and confidence was evaluated using the Fisher exact test, and the agreement among raters was assessed using the kappa test. Multiple linear regression analysis was performed to investigate whether the technical parameters could predict the effective dose. P-values<0.05 were considered to indicate statistical significance. Results: The optimized protocol (3 mA, 99 kVp, and 450 projection images) demonstrated good image quality and a lower effective dose for radiation-sensitive organs. Image quality and confidence had consistent values for all structures (P<0.05). Multiple linear regression analysis resulted in a statistically significant model. The milliamperage (b=0.504; t=3.406; P=0.027), kilovoltage peak (b=0.589; t=3.979; P=0.016) and number of projection images (b=0.557; t=3.762; P=0.020) were predictors of the effective dose. Conclusion: Optimized CBCT acquisition protocols can significantly reduce the effective radiation dose while maintaining acceptable image quality by adjusting the milliamperage and projection images.

• Computers and Concrete
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• v.14 no.5
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• pp.527-546
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• 2014

Portland cement concrete, which has higher strength and stiffness than asphalt concrete, has been widely applied on pavements. However, the brittle fracture characteristic of cement concrete restricts its application in highway pavement construction. Since the polypropylene fiber can improve the fracture toughness of cement concrete, Polypropylene Fiber-Reinforced Concrete (PFRC) is attracting more and more attention in civil engineering. In order to study the effect of polypropylene fiber on the generation and evolution process of the local deformation band in concrete, a series of three-point bending tests were performed using the new technology of the digital speckle correlation method for FRC notched beams with different volumetric contents of polypropylene fiber. The modified Double-K model was utilized for the first time to calculate the stress intensity factors of instability and crack initiation of fiber-reinforced concrete beams. The results indicate that the polypropylene fiber can enhance the fracture toughness. Based on the modified Double-K fracture theory, the maximum fracture energy of concrete with 3.2% fiber (in volume) is 47 times higher than the plain concrete. No effort of fiber content on the strength of the concrete was found. Meanwhile to balance the strength and resistant fracture toughness, concrete with 1.6% fiber is recommended to be applied in pavement construction.

• Steel and Composite Structures
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• v.23 no.5
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• pp.493-499
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• 2017

The behaviour of steel frames is highly influenced by the beam-column connections. Traditionally, Steel frames were usually designed assuming that connections are ideally pinned or fully rigid. A semi-rigid connection, however, creates a balance between the two extreme approaches mentioned above. In this research, two full scales of Extended End Plate Connections (EEPCs) were tested. Mathematical and numerical models were used to analyse the connections, and close correlations were found between these models and the corresponding tested specimens, which confirmed the confidence in the experimental results. The experimental results obtained enrich the available test data about behaviour of EEPC. In addition, the purpose of studying EEPC experimentally is to compare the stiffness and moment-rotation curve of EEPCs with that of Cap Plate Connections (CPCs), which were tested in a previous work. CPCs have not been studied sufficiently in the literature. The results obtained show that the typical CPC reduces the connection stiffness and these results will make a valuable contribution to the available test data in the research area of CPC.

• International Journal of Concrete Structures and Materials
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• v.10 no.4
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• pp.499-511
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• 2016

Reinforced concrete (RC) beams strengthened by externally bonded reinforcement often fail by debonding. This paper presents an experimental and analytical study aimed at better understanding and modeling the fiber reinforced polymer (FRP) debonding failures in strengthened RC beams under monotonic and cyclic loads. In order to investigate the flexural behavior and failure modes of FRP-strengthened beams under monotonic and cyclic loadings, an experimental program was carried out. An analytical study based on the energy balance of the system was also performed. It considers the dominant mechanisms of energy dissipation during debonding and predicts the failure load of the strengthened beams. Validation of the model was carried out using test data obtained from the own experimental investigation.

• Physical Therapy Korea
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• v.12 no.3
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• pp.11-21
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• 2005

The present study was aimed at investigating the effect of swimming training on brain function after focal cerebral ischemia in rats. Therefore, this study was examined on neurogenesis in dentate gyrus of hippocampus using 5-bromo-2'-deoxyuridine (BrdU) to label proliferating cells and assessed the neurological response following focal cerebral ischemia in rats using neurological motor behavioral test. In an observer-blinded fashion, twenty male Sprague-Dawley (280~310 g, 7 weeks old) rats were divided into four groups: MCAO plus swimming group (ME, $n_1$=5), MCAO plus control group (MC, $n_2$=5), SHAM plus swimming group (SE, $n_3$=5), SHAM plus control group (SC, $n_4$=5). The results of this study were as follows: 1) The limb placing time before and after swimming in the ME group were significantly longer than the MC group (p<.05), the SE group were significantly longer than the SC group (p<.01). 2) The balance beam scores before and after swimming in the ME group was higher than the SE group, the MC group was higher than the SC group but was not significantly different (p>.001). 3) The foot fault index before and after swimming training in ME group was significantly lower (i.e., improved) than the MC group (p<.001) and the SE group (p<.001), the SE group was significantly lower (i.e., improved) than the SC group (p<.001). 4) The mean number of BrdU-positive cells in the dentate gyrus in the ME group was significantly higher than the MC group (p<.001) and the SE group (p<.01). The MC group and the SE group was significantly higher than the SC group (p<.001). 5) There was significantly correlation between limb placing time and number of BrdU-positive cells on swimming training, there was positive correlation (r=.807, p<.0001) and between foot fault index and BrdU-positive cells number, there was negative correlation (r=-.503, p<.05). However, between balance beam scores and BrdU-positive cells number, there was no correlation. In conclusion, the present study demonstrates that the role of swimming training improves behavioral motor function probably by enhancing cell proliferation in that hippocampus. This study provides a model for investigating the stroke rehabilitation that underlies neurogenesis and functional ability.

• Journal of Korean Neurosurgical Society
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• v.38 no.1
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• pp.41-46
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• 2005

Objective : A study of the histopathologic and neurobehavioral correlates of cortical impact injury produced by increasing impact velocity using the controlled cortical impact[CCI] injury model is studied. Methods : Twenty-four Sprague-Dawley rats [$200{\sim}250g$] were given CCI injury using a pneumatically driven piston. Effect of impact velocity on a 3mm deformation was assessed at 2.5m/sec [n=6], 3.0m/sec [n=6], 3.5m/sec [n=6], and no injury [n=6]. After postoperative 24hours the rats were evaluated using several neurobehavioral tests including the rotarod test, beam-balance performance, and postural reflex test. Contusion volume and histopathologic findings were evaluated for each of the impact velocities. Results : On the rota rod test, all the injured rats exhibited a significant difference compared to the sham-operated rats and increased velocity correlated with increased deficit [p<0.001]. Contusion volume increased with increasing impact velocity. For the 2.5, 3.0, and 3.5m/sec groups, injured volumes were $18.8{\pm}2.3mm^3$, $26.8{\pm}3.1mm^3$, and $32.5{\pm}3.5mm^3$, respectively. In addition, neuronal loss in the hippocampal sub-region increased with increasing impact velocity. In the TUNEL staining, all the injured groups exhibited definitely positive cells at pericontusional area. However, there were no significant differences in the number of positive cells among the injured groups. Conclusion : Cortical impact velocity is a critical parameter in producing cortical contusion. Severity of cortical injury is proportional to increasing impact velocity of cortical injury.

• The Korea Journal of Herbology
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• v.21 no.2
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• pp.151-158
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• 2006

Objectives : The purpose of the present study is to observe the neuroprotective effect of the $NeuBo153^{\circledR}$ on transient focal cerebral ischemia in rats. Methods : $NeuBo153^{\circledR}$ was made by mixing the herbs, mainly the root of Panax ginseng, the root of Rehmannia glutinosa and Poria cocos, the stem bark of Acanthopanax senticosus, the root of Scutellaria baicalensis and Mel, and heating for 96 hours. Transient Focal cerebral ischemia (2 h of ischemia, 22 h of reperfusion) was induced by intraluminal suture method with SD rats. Sensory motor function was tested by rotarod test, prehensile traction test, beam balance test and foot fault test at 24 h after ischemia. The brain slices were stained by 2% 2, 3, 5-triphenyltetrazolium chloride and the infarct volume was measured by graphic analyzer at 24 h after ischemia. Results : $NeuBo153^{\circledR}$ treated group did not show significant differences compared with vehicle treated group in body temperature. Oral administration of $NeuBo153^{\circledR}$ reduced brain infarct volume by 29.7% compared with vehicle treated group. $NeuBo153^{\circledR}$ also showed protective effects on sensory motor functional deficits. Conclusion : $NeuBo153^{\circledR}$ treatment reduced brain damage and improved functional deficits induced by MCAo. It showed neuroprotective effects even when treatment was relayed 2 h after injury. Further research is required to evaluating long term functional recovery am accurate therapeutic range and mechanisms.