• Progress in Medical Physics
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• v.15 no.4
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• pp.228-236
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• 2004

Retinal ganglion cells transmit visual scene as an action potential to visual cortex through optic nerve. Conventional recording method using single intra- or extra-cellular electrode enables us to understand the response of specific neuron on specific time. Therefore, it is not possible to determine how the nerve impulses in the population of retinal ganglion cells collectively encode the visual stimulus with conventional recording. This requires recording the simultaneous electrical signals of many neurons. Recent advances in multi-electrode recording have brought us closer to understanding how visual information is encoded by population of retinal ganglion cells. We examined how ganglion cells act together to encode a visual scene with multi-electrode array (MEA). With light stimulation (on duration: 2 sec, off duration: 5 sec) generated on a color monitor driven by custom-made software, we isolated three functional types of ganglion cell activities; ON (35.0$\pm$4.4%), OFF (31.4$\pm$1.9%), and ON/OFF cells (34.6$\pm$5.3%) (Total number of retinal pieces = 8). We observed that nearby neurons often fire action potential near synchrony (< 1 ms). And this narrow correlation is seen among cells within a cluster which is made of 6～8 cells. As there are many more synchronized firing patterns than ganglion cells, such a distributed code might allow the retina to compress a large number of distinct visual messages into a small number of ganglion cells.

• Progress in Medical Physics
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• v.17 no.4
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• pp.260-267
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• 2006

A retinal ganglion cell's receptive field is defined as that region on the retinal surface In which a light stimulus will produce a response. A retinal ganglion cell peers out at a small patch of the visual scene through its receptive field and encodes local features with action potentials that pass through the optic nerve to higher centers. Therefore, defining the receptive field of a retinal ganglion cell is essential to understand the electrical characteristics of a ganglion cell. Distribution of receptive fields over retinal surface provides us an Insight how the retinal ganglion cell processes the visual scene. In this paper, we provide the details how to reconstruct the receptive field of a retinal ganglion cell. We recorded the ganglion cell's action potential with multielectrode array when the random checkerboard stimulus was applied. After classifying the retinal waveform Into ON-cell, OFF-cell, ON/OFF-cell, we reconstructed the receptive field of retinal ganglion cell with Matlab. Here, we show the receptive fields of ON-cell and OFF-cell.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.533-540
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• 2013

Purpose: To investigate the synaptic pattern of NMDA glutamate receptor subtype NMDA R1 on the dendritic arbors of ON-OFF direction-selective retinal ganglion cells (DS-RGSs) in developing [(5,10) days postnatal (PN)] mouse retina. Methods: ON-OFF DS-RGCs were injected with Lucifer yellow and the cells were identified by their characteristic morphology. To identify glutamatergic excitatory input from bipolar cell, we used a marker for the membrane traffic motor protein kinesin. Results: We identified DS-RGCs in P5, and P10 mouse retina. The immunofluorescence labeling of NMDA R1 was most prominent in the IPL. Our results showed that their presence upon the entire dendritic arbor of ON-OFF DS-RGCs is without any evidence of asymmetry, which would predict direction selectivity. Conclusions: The glutamatergic input from bipolar cell reveals symmetry pattern in all periods of P5, and P10. The results may suggest that direction selectivity not lies in the specific pattern of NMDA R1 receptors.

• Journal of the Korea Computer Industry Society
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• v.8 no.1
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• pp.49-56
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• 2007

Various kind of laser had been used on addition to endoscope for obstetrics and gynecology, gas laser such as CO2 laser had been used mainly much in laparoscope surgical operation mainly Thermal effect of beam displays other result different component parts of cellular tissue and different close of a marketplace of laser beam and priority solidification of temperature increase consists in cellular tissue, and cutting or carbonization process happens and evaporation by breakdown of cellular tissue happens more than $300^{\circ}$. <중략> Ostabilization of pulse transformer by high tension output module of CO2analog laser for obstetrics and gynecology that accomplish marks of honor kind switching and accuracy is required, and stabilize with laser output applying Turn-off in existent hard switching forward converter, on city happened switching damage, damage increase of output diode station recovery special quality, parasitism shock, design and result that manufacture, brought result that improve than existing product. Will be bought to get into superior result if supplement as systematic late.

• Molecules and Cells
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• v.38 no.6
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• pp.475-481
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• 2015

Programmable nucleases, which include zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and RNA-guided engineered nucleases (RGENs) repurposed from the type II clustered, regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) system are now widely used for genome editing in higher eukaryotic cells and whole organisms, revolutionising almost every discipline in biological research, medicine, and biotechnology. All of these nucleases, however, induce off-target mutations at sites homologous in sequence with on-target sites, limiting their utility in many applications including gene or cell therapy. In this review, we compare methods for detecting nuclease off-target mutations. We also review methods for profiling genome-wide off-target effects and discuss how to reduce or avoid off-target mutations.

• The Korean Journal of Pharmacology
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• v.16 no.1 s.26
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• pp.25-34
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• 1980

The in vitro guinea pig ureter responded to 5 sec trains of electrical stimuli with two contractions; the first an 'on response' (ON) occurred with $0.1{\sim}0.3$ sec after the onset o the stimulus train, the second an 'off response'(OFF) occurred $0.2{\sim}1.0$ sec after the termination of the stimulus train. Relaxation occurred between the two responses during a time when the stimulus was still being delivered. Longer duration and/or higher frequencies of stimuli within the train were required to elicit the OFF than the ON. Decreasing temperature from $37^{\circ}$ to $22^{\circ}$ decreased ON amplitude and increased OFF amplitude. $Ca^{++}$-free solution, 2 mM EDTA, 1 mM $Mn^{++}$ or $1{\mu}M$ verapamil rapidly abolished ON. OFF persisted when ON had disappeared by repeated stimulation at 0.12 train per sec. Conversely, caffeine, $50{\mu}M$ and theophylline, $10{\mu}M$ abolished OFF with only slight reduction of ON, and sodium nitroprusside decreased preferentially ON amplitude rather than OFF. Relaxation between ON and OFF was incomplete in low $Na^+$ solution. ON and OFF were not affected by the neural blockers tetrodotoxin, atropine or phentolamine, also pyrilamine and methysergide, and relaxation between ON and OFF was $Na^+$ dependent. Furthermore, ON depends on free $Ca^{++}$ and OFF is more dependent on bound or stored $Ca^{++}$.

• Applied Microscopy
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• v.38 no.3
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• pp.251-257
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• 2008

Human hair experience tensile forces during combing, bleaching and permanent dyeing processes. We have used rheometer to characterize bleached hair tensile response. Also, we investigated to morphological changes after tensile test of virgin hair and bleached hair using scanning electron microscopy. In tensile test, the tensile strength of virgin hair was $14.66g/cm^2$. They were measured as $12.95g/cm^2$, $12.61g/cm^2$ and $11.43g/cm^2$ for after the first, the second and the third trials of bleaching were done, respectively. Virgin hair had a higher tensile force than bleached hair. Tensile strength got lowered as more bleaching trials were done. In the observation of scanning electron microscopy, the fracture and lift-off of the cuticle outer layer were shown in virgin hair and bleached hair. The bleached hair were more lifted off at the outer cuticle layer than virgin hair. Consequently, chemical damage of bleaching agent caused weakening of the outer cuticle in the hair.

• Applied Microscopy
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• v.36 no.1
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• pp.25-33
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• 2006

This study applied a bleaching agent. which is commonly used in the beauty salons, to the hair of normal adult women, collected the hair immediately and 10 days and 20 days from the bleaching, were investigated the degree of degradation of the hair by using scanning and transmission electron microscopes. The surface of hair just after bleaching was observed to be similar to that of normal hair, showing no split or damage of scale. In the hair of 10 days after bleaching, however, the scale came off. From this time, scale on the cuticular layer of hair began to be separated. In 10 days from bleaching, the scale on the cuticular layer was separated from hair and some cytoplasm of cuticular cells was broken into pieces or fell off. The cell remains made the surface coarse and uneven. At this period, damaged scales had a sharp end. In the hair of 20 days after bleaching, scale fell off from the whole surface of the hair and the surface looked rough. On the bleached hair, many vacuoles were formed in the endocuticle of cuticular cells. As a result, deformation caused by the formation of vacuoles in cuticles broke up the cuticular cells.

• Progress in Medical Physics
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• v.9 no.2
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• pp.95-104
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• 1998

The dynamic properties of the 3rd-order neuron of the retina was investigated by using conventional intracellular recording techniques. Experiments were performed in the superfused retina-eyecup preparation of the channel catfish, Ictalurus punctatus. The cornea, iris, lens, and vitreous were removed by absorption with Kimwipe tissue under the dissection microscope thereby exposing the retina in a hemi -eyecup. The electrical signal was amplified by electrometer, viewed on oscilloscope. Regular signals from the cells were recorded on a penwriter and stored by data recorder and computer. Full-field, spot or annular light stimuli were generated on a computer monitor and focused onto the retina. Baclofen hyperpolarized the dark membrane potential, suppressed sustained component and enhanced transient component of the ON-sustained cell with a large transient component, but did not affect the surround antagonism of the cell. Baclofen selectively suppressed responses evoked by moving bar light stimuli on the ON-OFF transient cell. The results suggest that transient cells have directional selectivity in the inner retina. These dynamic properties of amacrine and ganglion cells were modulated by baclofen. Therefore, it is presumed that there is baclofen-induced directional selectivity in ON-OFF transient cells in the catfish retina.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.71-78
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• 1989

The structural changes in the pericarp of Panax ginseng fruit cells are studied during maturation periods. The pericarp can be divided into exocarp, mesocarp and endocarp. The exocarp consists of one layer of epidermal cells which is covered by a thin cuticle and hypodermal cells. A central vacuole and peripheral cytoplasm are observed in the exocarp and mesocarp. Also, irregular wall arrangement are observed during the differentiation. The endocarp is clearly marked off from the others by secondaw wall thickening and lignification. Secretory materials produced by the Golgi complex and rough endoplasmic reticulum vesicles appear to accumulated in the cell wall. These secretory materials are considered major components of the seed coat during the differentiation.