• Title/Summary/Keyword: rod cell

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Turbulent plane Couette-Poiseuille flow over a 2-D rod-roughened wall (2차원 표면조도가 있는 난류 평면 Couette-Poiseuille 유동에 대한 직접수치모사)

  • Kim, Jeong Hyun;Lee, Young Mo;Lee, Jae Hwa
    • Journal of the Korean Society of Visualization
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    • v.17 no.3
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    • pp.12-18
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    • 2019
  • Direct numerical simulation of a fully developed turbulent plane Couette-Poiseuille flow with a two-dimensional (2-D) rod-roughened wall is performed to investigate the impacts of the surface roughness. It is shown that the logarithmic region in the mean velocity profile over the rough wall Couette-Poiseuille flow is significantly shortened by the surface roughness compared to that over a turbulent Couette-Poiseuille flow with smooth wall. The Reynolds shear stress over the rough wall Couette-Poiseuille flow is decreased compared to that for a smooth case in the outer layer. These results are attributed to weakened turbulence activity or roll-cell mode over the rough wall Couette-Poiseuille flow near the channel centerline due to suppressed development of u'-structure on the top wall, as documented through spanwise energy spectra of the streamwise velocity fluctuations. Inspection of congregation motion near the bottom wall and time evolution of u'-structure reveal weakened co-supporting cycle for the rough wall case.

Retinal Development and Opsin Gene Expression during the Juvenile Development in Red Spotted Grouper (Epinephelus akaara)

  • Kim, Eun-Su;Lee, Chi-Hoon;Lee, Young-Don
    • Development and Reproduction
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    • v.23 no.2
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    • pp.171-181
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    • 2019
  • To produce healthy and stable seed production, we need to obtain information and understand vision that affects behavior of red spotted grouper. We examined their expression and retinal development during the juvenile development. Short-wavelength sensitive opsin (SWS2), a cone photoreceptor, began to be expressed from lens and ear vesicle formation stage and its expression increased until 10 days after hatching (dah). In case of middle-wavelength sensitive opsin (MWS), its expression was detected at 3 dah and reached the highest level at 21 dah. The expression of long-wavelength sensitive opsin (LWS) was first observed from 3 dah and their expression decreased thereafter. Rhodopsin, a rod photoreceptor, was found to be expressed from 2 dah and its expression reached the highest level at 50 dah. The outer nuclear layer (ONL), inner nuclear layer (INL) and ganglion cell layer began to differentiate at 2 dah, while choroid first appeared at 4 dah so that the eyes became black. These results indicate that the development of retina mostly completes around 4 dah. It seems that the development of the retina and the expression of the opsin genes are closely related to the behavior such as hunting prey, considering that the timing of the completion of the development of the retina, the timing of gene expression, and the timing of completion of yolk absorption are similar.

ASSESSMENT OF THE TiO2/WATER NANOFLUID EFFECTS ON HEAT TRANSFER CHARACTERISTICS IN VVER-1000 NUCLEAR REACTOR USING CFD MODELING

  • MOUSAVIZADEH, SEYED MOHAMMAD;ANSARIFAR, GHOLAM REZA;TALEBI, MANSOUR
    • Nuclear Engineering and Technology
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    • v.47 no.7
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    • pp.814-826
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    • 2015
  • The most important advantage of nanoparticles is the increased thermal conductivity coefficient and convection heat transfer coefficient so that, as a result of using a 1.5% volume concentration of nanoparticles, the thermal conductivity coefficient would increase by about twice. In this paper, the effects of a nanofluid ($TiO_2$/water) on heat transfer characteristics such as the thermal conductivity coefficient, heat transfer coefficient, fuel clad, and fuel center temperatures in a VVER-1000 nuclear reactor are investigated. To this end, the cell equivalent of a fuel rod and its surrounding coolant fluid were obtained in the hexagonal fuel assembly of a VVER-1000 reactor. Then, a fuel rod was simulated in the hot channel using Computational Fluid Dynamics (CFD) simulation codes and thermohydraulic calculations (maximum fuel temperature, fluid outlet, Minimum Departure from Nucleate Boiling Ratio (MDNBR), etc.) were performed and compared with a VVER-1000 reactor without nanoparticles. One of the most important results of the analysis was that heat transfer and the thermal conductivity coefficient increased, and usage of the nanofluid reduced MDNBR.

Effects of Treadmill Exercise on Cerebellar Astrocyte Activation and Purkinje Cell, and Motor Function in Aged Rats (트레드밀 운동이 노화 흰쥐 소뇌의 성상세포 활성과 퍼킨제 세포 및 운동기능 변화에 미치는 영향)

  • Lee, Hyo-Cheol;Kim, Hyung-Jun
    • 한국체육학회지인문사회과학편
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    • v.58 no.4
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    • pp.481-492
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    • 2019
  • The purpose of this study was to investigate the effects of treadmill exercise on cerebellar astrocyte activation and purkinje cells, neurotrophic factors expression, and motor function in aged rats. Sprague-Dawley (SD) rats were used and divided into three groups; (1) Young Control Group (YCG; 3months aged, n=10); (2) Old Control Group; (OCG; 24months aged, n=10); (3) Old Exercise Group (OEG; 24months aged, n=10). Rats were then subjected to treadmill exercise for 5 days per week for 12 weeks during which time the speed of the treadmill was gradually increased. The results revealed that in the rota-rod test, motor function was significantly increased in the OEG compared to the OCG (p<.05), and similarly YCG. Number of calbindin-positive purkinje cell expression significantly increased in the cerebellar vermis of OEG compared to the OCG (p<.05), and similarly YCG. GFAP-, NMDAR-positive cell expression significantly increased in the OEG (respectively p<.001), GFAP and GLAST protein levels were significantly increased in the cerebellum of OEG compared to the OCG (p<.05, p<.001) and similarly YCG. BDNF and NGF protein levels were highest in the YCG, increased in the OEG compared to OCG (p<.001, p<.05). These result show that regular exercise not only improved astrocyte activation, but also increased purkinje cell expression in the cerebellum and motor function by increasing the neurotrophic factors in aged rats.

Synthetic Strategy and Optical Property Characterization of Complex Nanorods: Plasmon Wave Guide and Solar Cell

  • Park, Sung-Ho
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.111-111
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    • 2012
  • In this talk, we represent a novel approach to investigating intra-nanorod surface plasmon coupling with control over block compositions. The multi-component rod-like nanostructures, which consist of optically active components (Au and Ag) and optically less active component (for example, Ni) in UV-vis-NIR spectral window, showed interesting optical response depending on each block length and the total length of the structure. By controlling the composition and relative lengths of the blocks that comprise these structures, we can tailor the overall optical properties. Depending on the relative fraction of Au and Ag blocks, the intensity of the transverse modes varied without noticeable peak shifts. However, the strong intraparticle surface plasmon coupling resulted in the collective appearance of longitudinal LSP modes, including higher-order modes. The experimental observations were confirmed by theoretical calculation, using a discrete dipole approximation method. In addition, we will briefly discuss how single nanorod solar cells can be synthesized by using by using electrochemical deposition and AAO hard templates.

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The $GABA_c$ Receptor Is Present in Isolated Cone-Horizontal Cell Axon Terminals From Catfish Retina

  • Jung, Chang-Sub;Lee, Sung-Jong;Paik, Sun-Sook;Bai, Sun-Ho
    • Proceedings of the Korean Biophysical Society Conference
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    • 1998.06a
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    • pp.35-35
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    • 1998
  • Catfish retina contains cone- and rod-horizontal cells. Only the cone-horizontal cell (cone-HC) has an axon and axon terminal. We compared the distribution of excitatory and inhibitory receptors in axon terminals and somata to begin to learn about the distinct functions of these two structures.(omitted)

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Antimicrobial Susceptibility of Microorganisms Isolated from Quarter Milk Samples of Holstein Cows (Holstein 유우의 유즙에서 분리한 유방염 원인균의 항균제 감수성)

  • 이정치;이채용;김상기;이정길;서국현
    • Journal of Veterinary Clinics
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    • v.20 no.2
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    • pp.166-171
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    • 2003
  • Milk samples were collected from a total of 418 quarters of 214 Holstein cows. Of these, samples which were positive on California Mastitis Test (CMT) and above 200,000 cells/ml by somatic cell counts were subjected to bacteriological examination and antimicrobial susceptibility test. Major pathogens responsible for mastitis included coagulase-negative staphylococci (34.3%), coagulase-positive staphylococci (21.5%), gran-negative rod (coliforms and noncoliforms: 12.6%) and Streptococcus spp. (8.4%). These strains were tested with 13 antimicrobial agents by the Kirby and Bauer standardized disc diffusion method. The isolated pathogens were mostly susceptible to amoxicillin and cephalothin, but were resistant to erythromycin.

Detergent Sensitivity of mrdA and mrdB Shape-Forming Mutants of Escherichia coli (대장균의 형태형성 변이주의 계면활성제 감수성)

  • Jun, Byoung-Kwon;Park, Sung-Dae;Lim, Si-Kyu;Park, Wan
    • Microbiology and Biotechnology Letters
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    • v.21 no.5
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    • pp.414-420
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    • 1993
  • Escherichia coli mrdAts and mrdBts mutants forming spherical cells at 42C, were employed to investigate the possible role of both inner and outer membrance structures in the determination of cell shape of gram-negative cells. Spherical cells, but not rod-shaped wild types, were specifically killed by anionic detergents, such as sarkosyl, sodium dodecylsulfate and sodium deoxycholate. From the spherical intact cells grown overnight at 42C, much more proteins were released by sakosyl.

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Visual Cells of the Introduced Bluegill Lepomis macrochirus (Pisces; Centropomidae) of Korea

  • Kim, Jae Goo;Park, Jong Young
    • Applied Microscopy
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    • v.46 no.2
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    • pp.89-92
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    • 2016
  • The bluegill Lepomis macrochirus is an invasive species, not native to Korea, introduced for aquaculture. This species is ranked as a new top predator due to its massive aquatic carnivorous and herbivorous nature by acute vision and the absence of a natural enemy. The visual cells of the retina of L. macrochirus are composed of short single cones and equal double cones and long and bulky rods by light and electron microscopes. In particular, the cones show a regular square mosaic arrangement. This pattern is widely considered as a strong predator. With regard to the visual system, this mosaic pattern may closely be related to a dynamic visual acuity to track and hunt prey.

Electrolytic Treatment Of Dilute Zinc And Cadmium Containing Aqueous Solutions (희석아연과 카드미늄을 함유한 수용액에서의 전해처리)

  • Kammel, Roland;Avci, Esref;Lieber, Hans Wilhelm
    • Journal of the Korean institute of surface engineering
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    • v.16 no.3
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    • pp.87-97
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    • 1983
  • 석출전위가 낮은 금속들을 저농도용액에서 전기분해하여 회수하는 방법에 대해 아연과 카드뮴을 모델로 삼아 채취방법을 연구하였다. Hull cell과 hyperbolic twin cell에서 시험해서 전류밀도와 효율이 낮기 때문에 기존방법으로는 회수속도가 매우 느린 것을 알 수 있었다. 전해 채취조건을 좋게 하기 위해서는 음극의 표면적을 크게 하고 흔들어 주며, 또 전해액을 강제 순환시켜 물질이동이 잘 되도록 해야만 한다. Rotating tubular bed reactor 나 impact rod reactor 같은 전해조를 사용하여 여러 종류의 용액 중의 아연과 카드뮴 전해 채취 실험을 하였다. 특히 카드뮴의 잔류농도를 낮추기 위해서는 전해법과 이온교환법을 같이 사용하는 것이 유용하다. 새로운 방법의 처리비용과 기존방법의 처리비용을 비교하여 보았다.

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