• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.69-72
• /
• 2005

In this study, effects of IHPs with various resting times to cell adhesion were investigated through the measurements of cell adhesive force, number and area of focal contacts (stained vinculin spots), and projected cell area, perimeter and circularity. In addition correlation tests and curve estimations using the experimental results were performed fur the finding an essential factor for increment of cell adhesive force. Tn the results, immediately after mechanical stimuli (150 minutes after seeding) and one hour later (210 minutes after seeding), the average adhesive force of experimental group 5 (resting time: 15min) compared with that of control group at same culture time was increased significantly (p<0.05). Average projected area and perimeter of cells at Group 5 were increased significantly (p<0.05), while average circularity of cells at Group 5 incubated fur 210 minutes was decreased significantly (p<0.05). In the digital image analysis of focal contacts containing vinculins, area and numbers of focal contacts per cell at Group 5 were higher than those of the other groups. This study indicated that IHP with appropriate resting time could contribute in improving cell adhesive force, cell spreading, development of cytoskeleton and formation of focal contacts. And cell adhesive force was correlated to the morphological aspects of cell and development of focal contacts. Particularly, area of focal contacts was closely related to cell adhesive force.

• Korean Journal of Acupuncture
• /
• v.35 no.4
• /
• pp.187-202
• /
• 2018

Objectives : Non-invasive transcranial electrical stimulation is one of therapeutic interventions to change in neural excitability of the cortex. Transcranial electro-acupuncture (TEA) can modulate brain functions through changes in cortical excitability as a model of non-invasive transcranial electrical stimulation. Some composites of fermented Scutellaria baicalenis (FSB) can activate intercellular signaling pathways for activation of brain-derived neurotrophic factor that is critical for formation of neural plasticity in stroke patients. This study was aimed at evaluation of combinatory treatment of TEA and FSB on behavior recovery and cortical neural excitability in rodent focal stroke model. Methods : Focal ischemic stroke was induced by photothrombotic injury to the motor cortex of adult rats. Application of TEA with 20 Hz and $200{\mu}A$ in combination with daily oral treatment of FBS was given to stroke animals for 3 weeks. Motor recovery was evaluated by rotating bean test and ladder working test. Electrical activity of cortical pyramidal neurons of stroke model was evaluated by using multi-channel extracellular recording technique and thallium autometallography. Results : Compared with control stroke group who did not receive any treatment, Combination of TEA and FSB treatment resulted in more rapid recovery of forelimb movement following focal stroke. This combination treatment also elicited increase in spontaneous firing rate of putative pyramidal neurons. Furthermore expression of metabolic marker for neural excitability was upregulated in peri-infract area under thallium autometallography. Conclusions : These results suggest that combination treatment of TEA and FSB can be a possible remedy for motor recovery in focal stroke.

• Progress in Medical Physics
• /
• v.23 no.1
• /
• pp.26-32
• /
• 2012

The magnification technique has recently become popular in bone radiography, mammography and other diagnostic examination. However, because of the finite size of X-ray focal spot, the magnification influences various imaging properties with resolution, noise and contrast. The purpose of study is to investigate the influence of magnification and focal spot size on digital imaging system using eDQE (effective detective quantum efficiency). Effective DQE is a metric reflecting overall system response including focal spot blur, magnification, scatter and grid response. The adult chest phantom employed in the Food and Drug Administration (FDA) was used to derive eDQE from eMTF (effective modulation transfer function), eNPS (effective noise power spectrum), scatter fraction and transmission fraction. According to results, spatial frequencies that eMTF is 10% with the magnification factor of 1.2, 1.4, 1.6, 1.8 and 2.0 are 2.76, 2.21, 1.78, 1.49 and 1.26 lp/mm respectively using small focal spot. The spatial frequencies that eMTF is 10% with the magnification factor of 1.2, 1.4, 1.6, 1.8 and 2.0 are 2.21, 1.66, 1.25, 0.93 and 0.73 lp/mm respectively using large focal spot. The eMTFs and eDQEs decreases with increasing magnification factor. Although there are no significant differences with focal spot size on eDQE (0), the eDQEs drops more sharply with large focal spot than small focal spot. The magnification imaging can enlarge the small size lesion and improve the contrast due to decrease of effective noise and scatter with air-gap effect. The enlargement of the image size can be helpful for visual detection of small image. However, focal spot blurring caused by finite size of focal spot shows more significant impact on spatial resolution than the improvement of other metrics resulted by magnification effect. Based on these results, appropriate magnification factor and focal spot size should be established to perform magnification imaging with digital radiography system.

• Therapeutic Science for Rehabilitation
• /
• v.7 no.3
• /
• pp.23-33
• /
• 2018

Objective : This systematic review aimed to investigate the effect of focal muscle vibration in patients with post-stroke spastic hemiplegia. Methods : We searched literature published between April 2009 and October 2017 using PubMed and RISS databases. The main search terms were Vibration therapy, Focal vibration, Somatosensory, Upper limb, and Spasticity after stroke. Based on inclusion/exclusion criteria, 6 articles were selected. Results : Articles on focal muscle vibration intervention ranged from evaluation of application-only vibration to muscle vibration with task-oriented activity. Intervention effects on upper extremity spasticity and function and activities of daily living were assessed. There were significant effects on upper extremity spasticity, function, and cortical excitability. Conclusions : This study can provide information on focal muscle vibration for use by clinical therapists. However, further studies are needed to identify the optimal stimulation site and frequency/amplitude of application to maximize the effects of focal muscle vibration.

• Korean Journal of Optics and Photonics
• /
• v.20 no.6
• /
• pp.354-360
• /
• 2009

We have constructed and analyzed the performance of a simple fiber bundle multi-focal microscope. The microscope had a fiber bundle substituted for micro-lens array that is the core part of MMM(multi-focal multi-photon microscope). The MMM is a type of confocal microscope. To analyze the performance and characteristics of the fiber bundle multi-focal microscope, three types of samples were used: a standard grating, USAF 1951(7, 3), and 1951(7, 6). Using two polarizers and a polarizing beam splitter, we eliminated noise and got clear images. We obtained the FWHM of fiber spot images with the standard grating using two different magnifier lenses which were 63X and 20X, and found an image of the sample as a distribution of fiber spot images. For this case we used the low magnification lens, which gives denser distribution, so that we could get clearer images. In order to test the resolution of the fiber bundle multi-focal microscopic system, we used the USAF 1951 sample which has a smaller line interval than that of the standard grating. The FWHM of the line width of the image coincides well with the real line width of the USAF 1951 sample. We confirmed the performance of a fiber bundle multi-focal microscopic system which is relatively simple but has submicron resolution and is able to get 1600 images at the same time.

• Communications of the Korean Mathematical Society
• /
• v.11 no.4
• /
• pp.917-924
• /
• 1996

We shall study some transfer theorems of finite groups with respect to a certain commutator subgroup, called "F-commutator" relative to any field F and apply the transfer to the fusion of a group H or to the focal subgroup of H.roup of H.

• Honam Mathematical Journal
• /
• v.34 no.2
• /
• pp.273-278
• /
• 2012

Using a comparison of the Jacobi differential equations instead of volume comparison by Itokawa in [3], the focal radius is estimated under the suitable Ricci and mean curvature conditions.

• Proceedings of the Optical Society of Korea Conference
• /
• 2007.07a
• /
• pp.19-20
• /
• 2007

• Journal of the Korean Society for Nondestructive Testing
• /
• v.27 no.1
• /
• pp.31-37
• /
• 2007

A $^{192}Ir$ small-focal source has been developed by using the HANARO reactor and the radioisotope production facility at the Korea Atomic Energy Research Institute (KAERI). The small-focal source with the dimension of 0.5 mm in diameter and 0.5 mm in length was fabricated as an aluminum-encapsulated form by a specially designed pressing equipment. For the estimation of the radioactivity, neutron self-shielding and ${\gamma}-ray$ self-absorption effects on the measured activity was considered. From this estimation, it is realized that $^{192}Ir$ small-focal sources over 3 Ci activities can be produced from the HANARO. Field performance tests were performed by using a conventional source and the developed source to take images of a computer CPU and a piece of a carbon steel. The small-focal source showed better penetration sensitivity and geometrical sharpness than the conventional source does. It is concluded from the tests that the focal dimension of this source is small enough to maximize geometrical sharpness in the image taking for the close proximity shots, pipeline crawler applications and contact radiography.

• Korean Journal of Optics and Photonics
• /
• v.11 no.6
• /
• pp.385-389
• /
• 2000

A phase-retardation function which was derived from Wigner distribution function (WDF) is used to increase a focal depth of a radially symmetric optical system. The WDF for one-dimensional signal is represented as a two-dimensional function of phasespace ($\chi,\zeta$), and a normalized irradiance is described as a form of the Strehl ratio (SR). The increase in the focal depth is accomplished by delivering a shearing tilt a that represents a characteristic of free space propagation with simple manipulation in the WDF space. In this paper we propose a method for evaluating the focal depth quantitatively by representing the phaseretardation function in terms of the focal depth term. In order to verify the validity of the proposed method, we compared the numerically analyzed result with that of J. Sochki's study. study.