• Title/Summary/Keyword: Biomedical Applications

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Research Trends in Powder Materials for Solution-based Transparent Conducting Electrode (용액기반 투명전극 분말 재료 연구 동향)

  • Koo, Bon-Ryul;Ahn, Hyo-Jin
    • Journal of Powder Materials
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    • v.24 no.2
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    • pp.153-163
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    • 2017
  • Transparent conducting electrodes (TCEs) are attracting considerable attention as an important component for emerging optoelectronic applications such as liquid crystal displays, touch panels, and solar cells owing to their attractive combination of low resistivity (<$10^{-3}{\Omega}cm$) and high transparency (>80%) in the visible region. The solution-based process has unique properties of an easy fabrication procedure, scalability, and low cost compared to the conventional vacuum-based process and may prove to be a useful process for fabricating TCEs for future optoelectronic applications demanding large scale and flexibility. In this paper, we focus on the introduction of a solution-based process for TCEs. In addition, we consider the powder materials used to fabricate solution-based TCEs and strategies to improve their transparent conducting properties.

Electrical Impedance Tomography and Biomedical Applications

  • Woo, Eung-Je
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.06a
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    • pp.1-6
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    • 2007
  • Two impedance imaging systems of multi-frequency electrical impedance tomography (MFEIT) and magnetic resonance electrical impedance tomography (MREIT) are described. MFEIT utilizes boundary measurements of current-voltage data at multiple frequencies to reconstruct cross-sectional images of a complex conductivity distribution (${\sigma}+i{\omega}{\varepsilon}$) inside the human body. The inverse problem in MFEIT is ill-posed due to the nonlinearity and low sensitivity between the boundary measurement and the complex conductivity. In MFEIT, we therefore focus on time- and frequency-difference imaging with a low spatial resolution and high temporal resolution. Multi-frequency time- and frequency-difference images in the frequency range of 10 Hz to 500 kHz are presented. In MREIT, we use an MRI scanner to measure an internal distribution of induced magnetic flux density subject to an injection current. This internal information enables us to reconstruct cross-sectional images of an internal conductivity distribution with a high spatial resolution. Conductivity image of a postmortem canine brain is presented and it shows a clear contrast between gray and white matters. Clinical applications for imaging the brain, breast, thorax, abdomen, and others are briefly discussed.

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A Design of 10-bit 100Ks/S Successive Approximation A/D Converter for Biomedical Applications (의료 기기용 10bit, 100Ks/S Successive Approximation A/D Converter 설계)

  • Kim, Jae-Woon;Burm, Jin-Wook;Lim, Shin-Il
    • Proceedings of the KIEE Conference
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    • 2007.10a
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    • pp.481-482
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    • 2007
  • This paper describes the design of a l0-bit 100 KSample/S CMOS A/D Converter for biomedical applications such as pulse oximetry, body weight scale, ECG etc. We adopted an asynchronous architecture in the 10-b DAC design and hence reduces the number of switches by 11 and resistors by 64 compared with the conventional l0-b DAC. We also reduced the power consumption compare with the conventional architecture by 0.4mW. Output offset cancellation technique is applied to the design of comparator. The total power consumption of designed circuit is 190uW at the supply voltage of 1.8V with the 0.18um general CMOS technology.

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Nanocellulose Applications for Drug Delivery: A Review

  • Lee, Seung-Hwan;Kim, Hyun-Ji;Kim, Jin-Chul
    • Journal of Forest and Environmental Science
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    • v.35 no.3
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    • pp.141-149
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    • 2019
  • Nanocellulose, which can exist as either cellulose nanocrystals or cellulose nanofibrils, has been used as a biomaterial for drug delivery owing to its non-immunogenicity, biocompatibility, high specific area, good mechanical properties, and variability for chemical modification. Various water-soluble drugs can be bound to and released from nanocelluloses through electrostatic interactions. The high specific surface area of nanocellulose allows for high specific drug loading. Additionally, a broad spectrum of drugs can bind to nanocellulose after facile chemical modifications of its surface. Controlled release can be achieved for various pharmaceuticals when the nanocellulose surface is chemically modified or physically formulated in an adequate manner. This review summarizes the potential applications of nanocelluloses in drug delivery according to published studies on drug delivery systems.

A guideline for the statistical analysis of compositional data in immunology

  • Yoo, Jinkyung;Sun, Zequn;Greenacre, Michael;Ma, Qin;Chung, Dongjun;Kim, Young Min
    • Communications for Statistical Applications and Methods
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    • v.29 no.4
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    • pp.453-469
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    • 2022
  • The study of immune cellular composition has been of great scientific interest in immunology because of the generation of multiple large-scale data. From the statistical point of view, such immune cellular data should be treated as compositional. In compositional data, each element is positive, and all the elements sum to a constant, which can be set to one in general. Standard statistical methods are not directly applicable for the analysis of compositional data because they do not appropriately handle correlations between the compositional elements. In this paper, we review statistical methods for compositional data analysis and illustrate them in the context of immunology. Specifically, we focus on regression analyses using log-ratio transformations and the alternative approach using Dirichlet regression analysis, discuss their theoretical foundations, and illustrate their applications with immune cellular fraction data generated from colorectal cancer patients.

SYNTHESIS OF BLOCK COPOLYMERS CONTAINING POLYPEPTIDE AND ITS BIOMEDICAL APPLICATION

  • Cho, Chong-Su
    • Proceedings of the Korean Society of Sericultural Science Conference
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    • 1997.06a
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    • pp.159-169
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    • 1997
  • ABA-type(or AB) block copolymers composed of poly(${\gamma}$-alkyl L-glutamate) (PALG)[or poly(L-leucine)] as the A component and polyether[or poly (N-isopropy1 acrylamide) as the B component were synthesized by polymerization of (${\gamma}$-alkyl L-glutamate N-carboxyanhydride initiated by primary amined located at both(or one) ends of the polymer chains. Structural studies of the block copolymers were performed in the solution and solid state. Also, artificial skin, drug delivery system of the block copolymers and cell attachment onto the copolymer were carried out for biomedical applications.