• Title/Summary/Keyword: Biological Engineering

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Effectiveness of Flashing Light for Increasing Photosynthetic Efficiency of Microalgal Cultures over a Critical Cell Density

  • Park, Kyong-Hee;Lee, Choul-Gyun
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.6 no.3
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    • pp.189-193
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    • 2001
  • Critical cell density (CCD), the maximum cell concentration without mutual shading in algal cultures, can be used as a new operating parameter for high-density algal cultures and for the application of the flashing light effect on illuminated algal cultures. CCD is a function of average cell volume and light illumination area. The CCD is thus proposed as an index of estimation of mutual shading in algal cultures. Where cell densities are below the CCD, all the cells in photobioreactors can undergo photosysnthesis at their maximum rate. At cell densities over CCD, mutual shading will occur and some cells in the illumination chamber cannot grow photoautotrophically. When the cell concentration is higher than the CCD, specific oxygen production rates under flashing light were higher than those under continuous light. The CCD was found to be a useful engineering parameter for the application of flashing light, particularly in high-density algal cultures.

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A Study on the Correlation between Visual and Auditory Emotion (시각과 청각 자극에 의한 감성정보의 연관성에 관한 연구)

  • Han, B.H.;Kim, J.H.;Kim, N.G.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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    • pp.27-30
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    • 1997
  • The purpose of this study is to estimate human sensibility quantitatively under color and music stimulation and to examine the correlation between visual and auditory emotion. We measured biological signals such as EEG, ECG, skin conductance and the number of respiration in order to compare color with music sensibilities. Our result showed that red, yellow and violet color provoked active and exciting senses dominatively as dance, rock and blues music. While blue, cyan and pink color were involved in tranquil and resting emotions deeply as classic and ballade music. Our quantitative estimations of human sensibilites are useful in the design of manufactured goods.

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Isolation and Identification of a Pentachloronitrobenzene(PCNB) Degrading Bacterium Alcaligenes xylosoxidans PCNB-2 from Agricultural Soil

  • Shin, Sung-Kyu;Kim, Jang-Eok;Kwon, Gi-Seok;Kwon, Jin-Wook;Oh, Eun-Taex;So, Jae-Seong;Koh, Sung-Cheol
    • Journal of Microbiology
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    • v.41 no.2
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    • pp.165-168
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    • 2003
  • We report a new PCNB-degrading strain (PCNB-2) that is able to utilize and grow on PCNB (100 ppm) as a sole carbon source. This strain was identified as Alcaligenes xylosoxidans based upon 16S rDNA sequence analysis, API 20 NE tests and cell membrane lipid analysis. The new PCNB degrader Alcaligenes xylosoxidans PCNB-2 could find use in bioremediation of PCNB, which is environmentally persistent.

DNA Repair of Eukaryotes Associated with Non-coding Small RNAs

  • Kang, Han-Chul;Yoon, Sang-Hong;Lee, Chang-Muk;Roh, Kyung Hee
    • Journal of Applied Biological Chemistry
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    • v.56 no.1
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    • pp.37-42
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    • 2013
  • In eukaryotes, most of the genome are transcribed, however only a small proportion of total transcripts encodes for protein, thus resulting in many of noncoding RNAs. In order to recover DNA damage including DNA double-strand breaks (DSBs) eukaryotes have evolved complex mechanisms and these are processed through coordinated mechanisms of protein sensors, transducers, and effectors including RNAs. During recent years, small RNAs have been increasingly studied and gradually considered as key regulators in various aspects of biology. Upon DNA damage, small RNAs including diRNAs (DSB induced RNA) are generated in both plant and human cell lines. Inhibition of their biogenesis has severe influence on DSB repair system.

Integrate-and-Fire Neuron Circuit and Synaptic Device with Floating Body MOSFETs

  • Kwon, Min-Woo;Kim, Hyungjin;Park, Jungjin;Park, Byung-Gook
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.6
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    • pp.755-759
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    • 2014
  • We propose an integrate-and-fire neuron circuit and synaptic devices with the floating body MOSFETs. The synaptic devices consist of a floating body MOSFET to imitate biological synaptic characteristics. The synaptic learning is performed by hole accumulation. The synaptic device has short-term and long-term memory in a single silicon device. I&F neuron circuit emulate the biological neuron characteristics such as integration, threshold triggering, output generation, and refractory period, using floating body MOSFET. The neuron circuit sends feedback signal to the synaptic transistor for long-term memory.

Micro Energy Harvesting System Based On Reverse Electro Wetting On Dielectric (REWOD) (역전기습윤현상을 이용한 소형 에너지 수확장치)

  • Cho, Jin Hyun;Kim, Gil Yeon;Choi, Sang Beak;Jeon, Tae-joon;Kim, Sun Min
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.6
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    • pp.27-30
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    • 2015
  • In this study, we attempted to harvest energy using water droplet based on Reverse Electro Wetting On Dielectric (REWOD) phenomenon between water droplet and dielectric surface without external bias. REWOD device can be fabricated via simple coating process, which is highly economic and easy. We believe that our system is well-suited for IoT(Internet of Things) embedded electronics that require low but consistent electricity. Moreover, our device can be integrated with window to generate electricity upon raindrops.

Organic thin-film transistors and transistor diodes with transfer-printed Au electrodes

  • Cho, Hyun-Duck;Lee, Min-Jung;Yoon, Hyun-Sik;Char, Kook-Heon;Kim, Yeon-Sang;Lee, Chang-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1122-1124
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    • 2009
  • Organic thin-film transistors (OTFTs) were fabricated by using the transfer patterning method. In order to remove Au pattern easily, UV-curable polymer mold was surface treated. Au source/drain (S/D) pattern was transferred to insulator-coated substrate surface. Fabricated OTFTs were compared to OTFTs using vacuum-deposited Au S/D. Additionally, transistor diodes were characterized.

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Hybrid Block Coding of Medical Images Using the Characteristics of Human Visual System

  • Park, Kwang-Suk;Chee, Young-Joon
    • Journal of Biomedical Engineering Research
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    • v.15 no.1
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    • pp.57-62
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    • 1994
  • The demand of image compression is increasing now for the integration of medical images into the hospital information system. Even though the quantitative distortion can be measured from the difference between original and reconstructed images, it doesn't include the nonlinear characteristics of human visual system. In this study, we have evaluated the nonlinear characteristics of human visual system and applied them to the compression of medical images. The distortion measures which reflect the characteristics of human visual system has been considered. This image compression procedure consists of coding scheme using JND (Just Noticeable Difference) curve, polynomial approximation and BTC (Block Truncation Coding). Results show that this method can be applied to CT images, scanned film images and other kinds of medical images with the compression ratio of 5-10:1 without any noticeable distortion.

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Microbead-based bio-assay using quantum dot fluorescence in a microfluidic chip (미소유체 칩 상에서 Quantum Dot 및 마이크로 비드를 이용한 생체물질 분석)

  • Yun, Kwang-Seok;Lee, Do-Hoon;Kim, Hak-Sung;Yoon, Eui-Sik
    • Journal of Sensor Science and Technology
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    • v.14 no.5
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    • pp.308-312
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    • 2005
  • We present a microfluidic chip designed for the detection of antibody by using quantum dots fluorescence and a microbead-based assay. A custom designed PDMS microfluidic chip with multi-layer channel is utilized for capturing microbeads; antibody injection into each micro-well; QD injection; and fluorescence detection. The experiment using the fabricated microfluidic chip has been performed on solutions with various concentrations of antibody and has shown correlated fluorescent intensities.

EEG signal display as a multirate sampling problem (멀티레이터 샘플링 문제로서의 뇌파신호 디스플레이)

  • Choi, H.G.;Oh, Y.S.;Lee, S.J.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.311-314
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    • 1996
  • The display of biological signals in monitors often involves a multirate sampling operation which consists of decimation and intenolation. All electroencephalographic (EEG) samples of 10 to 30 seconds must be displayed in the computer screen to keep the aspect ratio of the paper polygraph output. Since the current affordable display technology plots at most 2,000 pixels per row, some samples need to be discarded. This paper studies methods to perform this operation characterizing them from the signal processing viewpoint and compares the display quality among several decimations. Experimental results show that a nonlinear operation such as the peak detection could be preferable than the canonical linear filtering to reduce aliasing.

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