• Title/Summary/Keyword: biological methods

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Computational Simulation on Power Prediction of Lithium Secondary Batteries by using Pulse-based Measurement Methods (펄스 측정법에 기반한 리튬이차전지 출력 측정에 관한 전산 모사)

  • Park, Joonam;Byun, Seoungwoo;Appiah, Williams Agyei;Han, Sekyung;Choi, Jin Hyeok;Ryou, Myung-Hyun;Lee, Yong Min
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.33-38
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    • 2015
  • Energy storage systems (ESSs) have been utilized widely in the world to optimize the power operation system and to improve the power quality. As lithium secondary batteries are the main power supplier for ESSs, it is very important to predict its cycle and power degradation behavior. In particular, the power, one of the hardest electrochemical properties to measure, needs lots of resources such as time and facilities. Due to these difficulties, computer modelling of lithium secondary batteries is applied to predict the DC-IR and power value during charging and discharging as a function of state of charge (SOC) by using pulse-based measurement methods. Moreover, based on the hybrid pulse power characteristics (HPPC) and J-Pulse (JEVS D 713, Japan Electric Vehicle Association Standards) methods, their electrochemical properties are also compared and discussed.

Antimicrobial Activity of Caffeic acid-functionalized ZnO Nanoparticles

  • Choi, Kyong-Hoon;Hong, Dae Eui;Kim, Ho-Joong;Park, Bong Joo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.380.2-380.2
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    • 2016
  • The emergence of new infectious diseases, the resurgence of several infections that appeared to have been controlled and the increase in bacterial resistance have created the necessity for studies directed towards the development of new antimicrobials. In the present study, we have synthesized a novel antioxidant ZnO nanoparticle that is newly designed and prepared by simple surface modification process. Antioxidative functionality is provided by the immobilization of antioxidant 3-(3,4-dihydroxyphenyl)-2-propenoic acid (caffeic acid, CA) onto the surface of ZnO nanoparticles. Microstructure and physical properties of the ZnO@CA nanoparticles were investigated by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR) and steady state spectroscopic methods. Antimicrobial Activities of ZnO@CA nanoparticles were measured against various bacterial strains using antibacterial testing methods.

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Invasive and non-invasive methods for estimating the optical properties of tissue at laser wavelengths (레이저 파장에서의 생체 침습적 및 비침습적 광학계수 측정 방법)

  • Yoon, Gil-Won
    • Proceedings of the KOSOMBE Conference
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    • v.1994 no.12
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    • pp.147-150
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    • 1994
  • To predict light propagation in biological tissues irradiated by laser, the optical properties such as absorption and scattering coefficients are required. There have been various techniques for measuring these coefficients. One method requires tissue samples, often a slab of thin tissue, is invasive. On the other hand, non-invasive method usually measures back-scattered light from a subject with no physical intervent ions. Advantages and disvantages of using different methods are investigated. A careful attention should be made in order to select the best method for a given experimental condition since, even either for invasive or non-invasive method, accuracy is subject to governing models and sample preparations.

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Progresses in membrane and advanced oxidation processes for water treatment

  • Khulbe, K.C.;Feng, C.Y.;Matsuura, T.;Ismail, A.F.
    • Membrane and Water Treatment
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    • v.3 no.3
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    • pp.181-200
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    • 2012
  • At present water crisis is not an issue of scarcity, but of access. There is a growing recognition of the need for increased access to clean water (drinkable, agricultural, industrial use). An encouraging number of innovative technologies, systems, components, processes are emerging for water-treatment, including new filtration and disinfectant technologies, and removal of organics from water. In the past decade many methods have been developed. The most important membrane-based water technologies include reverse osmosis (RO), ultrafiltration (UF), microfiltration (MF), and nanofiltration. Beside membrane based water-treatment processes, other techniques such as advanced oxidation process (AOP) have also been developed. Some unconventional water treatment technology such as magnetic treatment is also being developed.

Evaluation of Advanced Structure-Based Virtual Screening Methods for Computer-Aided Drug Discovery

  • Lee, Hui-Sun;Choi, Ji-Won;Yoon, Suk-Joon
    • Genomics & Informatics
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    • v.5 no.1
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    • pp.24-29
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    • 2007
  • Computational virtual screening has become an essential platform of drug discovery for the efficient identification of active candidates. Moleculardocking, a key technology of receptor-centric virtual screening, is commonly used to predict the binding affinities of chemical compounds on target receptors. Despite the advancement and extensive application of these methods, substantial improvement is still required to increase their accuracy and time-efficiency. Here, we evaluate several advanced structure-based virtual screening approaches for elucidating the rank-order activity of chemical libraries, and the quantitative structureactivity relationship (QSAR). Our results show that the ensemble-average free energy estimation, including implicit solvation energy terms, significantly improves the hit enrichment of the virtual screening. We also demonstrate that the assignment of quantum mechanical-polarized (QM-polarized) partial charges to docked ligands contributes to the reproduction of the crystal pose of ligands in the docking and scoring procedure.

Validation Process of HPLC Assay Methods of Drugs in Biological Samples (생체시료내 약물의 HPLC 분석법에 대한 유효성 검토방법)

  • Chi, Sang-Cheol;Jun, H.-Won
    • Journal of Pharmaceutical Investigation
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    • v.21 no.3
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    • pp.179-188
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    • 1991
  • An HPLC assay method of a drug to be applied to the pharmacokinetic studies of the drug should be completely validated. The validation process for an HPLC assay method in a biological sample was discussed using the data obtained from the development of HPLC method for the simultaneous quantitation of verapamil and norverapamil in human serum. The validation criteria included were specificity, linearity, accuracy, precision, sensitivity, recovery, drug stability, and ruggedness of an assay method.

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Epimers/Metabolites of Tetracycline Derivatives; Biological Activity and Regulation Aspects for MRL in Food (생물학적활성을 기초로 한 테트라싸이클린계 항생물질 잔류스크리닝법의 개선과 식품 중 잔류허용기준 설정 개선)

  • Kwon, Jin-Wook;Yun, Hyo-In;Lee, Kyu-Seung
    • Korean Journal of Environmental Agriculture
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    • v.30 no.1
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    • pp.82-88
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    • 2011
  • BACKGROUND: Tetracyclines (TCs) are mainly regulated as parent compounds by bioactivity-based screening methods in food. Especially with respect to antimicrobial residues, their metabolites/epimers are also highly concerning chemicals and traditionally applied microbial detection methods are needed to improve with validation for regulatory control. METHODS AND RESULTS: Detection capability and biological activity of tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC) and their epimers; anhydrotetracycline (ATC), epianhydrotetracycline (EATC), epitetracycline (ETC), 4-epi-chlortetracycline (ECTC), 4-epianydrochlotetra-cycline (EACTC), 4-epioxychlortetracycline (EOTC), were measured by microbial growth inhibition screening method of Korea Food Code. CONCLUSION(S): Limited detection capabilities were found, B. megarerium and B. subtilis showed for TC and CTC, and B. subtilis for OTC. Biological potency of each epimer was also presented against various microorganisms, at the level from 50% to 96%, comparing with parent TCs. It is recommended that more advanced microbial screening methods with validation are needed, and biologically active epimers are to be considered as marker residues for MRL setting of regulatory control purpose.

Evaluation of Total Residues of Imidacloprid in Livestock Products from Domestic Markets by using a Simultaneous Analytical Method Based on QuEChERS (QuEChERS 기반 동시분석법을 이용한 국내 유통 축산물 중 Imidacloprid 총잔류량 평가)

  • Seung Won Lee;Ji Hyun Yoon;Ji Yu Kim;Da Jung Lim;Hyung Wook Jo;Joon Kwan Moon;Hye-Min Gwak;Hee-Ra Chang;In Seon Kim
    • Korean Journal of Environmental Agriculture
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    • v.42 no.3
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    • pp.220-230
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    • 2023
  • Imidacloprid is a neonicotinoid insecticide widely used for insect control in a variety of crops. The evaluation of imidacloprid total residues in animal feeds derived from crop by-products is required to ensure the safety of livestock products. We performed simultaneous LC/MS/MS analyses of imidacloprid and its metabolites in five different livestock products including beef, pork, chicken, milk and egg from domestic markets. The methods for sample preparation and instrumental analysis were established by modifying QuEChERS method to meet the Codex guidelines. The methods generated 0.0035 mg/kg of the limit of determination (LOD), 0.01 mg/kg of the limit of quantitation (LOQ) and standard calibration linearity with >0.983 of the coefficients of determination (R2). The methods exhibited the recovery values of imidacloprid and its metabolites ranging from 65.66 to 119.27% without any interference between matrices. Imidacloprid total residues in the livestock products were found as values lower than the LOQ and maximum residue limits (MRLs). This study suggests that the methods are successfully applicable for the safety evaluation of imidacloprid total residues in livestock products from domestic markets.

An Exploration of the Teaching/Learning Methods of Bioethics Appropriate for Ethical Theories and Socio-scientific Issues in Biological Sciences (윤리학 이론과 생명과학 관련 사회과학적 논쟁거리에 적절한 생명윤리 교수-학습 방법의 탐색)

  • Shim, Mee-Young;Cho, Hee-Hyung
    • Journal of The Korean Association For Science Education
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    • v.29 no.5
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    • pp.513-530
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    • 2009
  • Many kinds of teaching methods have been used to instruct ethical issues that arise in the field of science and technology. However, few teaching methods of bioethics have been validated by ethical theories, or justified based on practical utility in bioethics teaching. The aim of this article is to suggest teaching methods of bioethics that are appropriate for ethical theories and socio-scientific issues related to biological sciences in secondary schools. In the article, the teaching methods are classified into three types of ethical theories and into three types of socio-scientific issues in biological sciences. The characteristics of nine teaching/learning methods are then described in terms of appropriate bioethical issues or contexts, and ethical theories or principles.