• Title/Summary/Keyword: Molecular techniques

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Application of Molecular Simulation Techniques to Estimation of Gas Permeability in Zeolite Membranes

  • Takaba, Hiromitsu;Yamamoto, Atsushi;Nakao, Shin-Ichi
    • Proceedings of the Membrane Society of Korea Conference
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    • 2004.05a
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    • pp.33-38
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    • 2004
  • Molecular modeling of gas permeation through zeolite membranes with/without intercrystalline region was carried out. Molecular dynamics (MD) and Monte Carlo (MC) simulations were performed to estimate the diffusion coefficient and adsorption parameters respectively, and our proposed combined method of molecular simulation techniques with a permeation theory (CMP) was used to estimate gas permeability. The calculated permeability of gases (Ar, He, Ne, $N_2$, $0_2$, $CH_4$) at 301 K for the single crystal membrane model was about one order of magnitude larger than the experiential values, although the dependence on the molecular weight of the permeating species agreed with experiments. On the other hand, the estimated permeability using the diffusivity and adsorption parameters of the intercrystalline region model was in good agreement with the experiments. The consistency between experiments and the estimated values means the importance of considering the intercrystalline region and the validity of CMP method to predict the performance of zeolite membranes.

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Clearing and Labeling Techniques for Large-Scale Biological Tissues

  • Seo, Jinyoung;Choe, Minjin;Kim, Sung-Yon
    • Molecules and Cells
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    • v.39 no.6
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    • pp.439-446
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    • 2016
  • Clearing and labeling techniques for large-scale biological tissues enable simultaneous extraction of molecular and structural information with minimal disassembly of the sample, facilitating the integration of molecular, cellular and systems biology across different scales. Recent years have witnessed an explosive increase in the number of such methods and their applications, reflecting heightened interest in organ-wide clearing and labeling across many fields of biology and medicine. In this review, we provide an overview and comparison of existing clearing and labeling techniques and discuss challenges and opportunities in the investigations of large-scale biological systems.

Trend of In Silico Prediction Research Using Adverse Outcome Pathway (독성발현경로(Adverse Outcome Pathway)를 활용한 In Silico 예측기술 연구동향 분석)

  • Sujin Lee;Jongseo Park;Sunmi Kim;Myungwon Seo
    • Journal of Environmental Health Sciences
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    • v.50 no.2
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    • pp.113-124
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    • 2024
  • Background: The increasing need to minimize animal testing has sparked interest in alternative methods with more humane, cost-effective, and time-saving attributes. In particular, in silico-based computational toxicology is gaining prominence. Adverse outcome pathway (AOP) is a biological map depicting toxicological mechanisms, composed of molecular initiating events (MIEs), key events (KEs), and adverse outcomes (AOs). To understand toxicological mechanisms, predictive models are essential for AOP components in computational toxicology, including molecular structures. Objectives: This study reviewed the literature and investigated previous research cases related to AOP and in silico methodologies. We describe the results obtained from the analysis, including predictive techniques and approaches that can be used for future in silico-based alternative methods to animal testing using AOP. Methods: We analyzed in silico methods and databases used in the literature to identify trends in research on in silico prediction models. Results: We reviewed 26 studies related to AOP and in silico methodologies. The ToxCast/Tox21 database was commonly used for toxicity studies, and MIE was the most frequently used predictive factor among the AOP components. Machine learning was most widely used among prediction techniques, and various in silico methods, such as deep learning, molecular docking, and molecular dynamics, were also utilized. Conclusions: We analyzed the current research trends regarding in silico-based alternative methods for animal testing using AOPs. Developing predictive techniques that reflect toxicological mechanisms will be essential to replace animal testing with in silico methods. In the future, since the applicability of various predictive techniques is increasing, it will be necessary to continue monitoring the trend of predictive techniques and in silico-based approaches.

Direct Analysis in Real Time Mass Spectrometry: a Powerful Tool for Fast Analysis

  • Li, Xianjiang;Wang, Xin;Li, Linnan;Bai, Yu;Liu, Huwei
    • Mass Spectrometry Letters
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    • v.6 no.1
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    • pp.1-6
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    • 2015
  • Direct analysis in real time mass spectrometry (DART-MS) is one of the variants of ambient mass spectrometry. The ionization process of DART-MS is in open environment and only takes few seconds, so it is suitable for fast analysis. Actually, since its introduction in 2005, more and more attentions have been drawn to its various applications due to its excellent properties, e.g., fast analysis, and no or less sample preparation, high salt tolerance and so on. This review summarized the promising features of DART-MS, including its ionization mechanism, equipment modification, wide applications, coupling techniques and extraction strategies before analysis.

Quantitation of In-Vivo Physiological Function using Nuclear Medicine Imaging and Tracer Kinetic Analysis Methods (핵의학 영상과 추적자 동력학 분석법을 이용한 생체기능 정량화)

  • Kim, Su-Jin;Kim, Kyeong-Min;Lee, Jae-Sung
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.2
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    • pp.145-152
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    • 2008
  • Nuclear medicine imaging has an unique advantage of absolute quantitation of radioactivity concentration in body. Tracer kinetic analysis has been known as an useful investigation methods in quantitative study of in-vivo physiological function. The use of nuclear medicine imaging and kinetic analysis together can provide more useful and powerful intuition in understanding biochemical and molecular phenomena in body. There have been many development and improvement in kinetic analysis methodologies, but the conventional basic concept of kinetic analysis is still essential and required for further advanced study using new radiopharmaceuticals and hybrid molecular imaging techniques. In this paper, the basic theory of kinetic analysis and imaging techniques for suppressing noise were summarized.

A Conformational Study of Linkage Positions in Oligosaccharides Investigated by 2-D NMR Spectroscopy and Molecular Modeling

  • Yoo Yoon, Eun-Sun
    • Bulletin of the Korean Chemical Society
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    • v.24 no.3
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    • pp.339-344
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    • 2003
  • The conformation of synthetic oligosaccharide can be elucidated by employing molecular modeling and highfield proton NMR (nuclear magnetic resonance) spectroscopy. Information with respect to the composition and configuration of saccharide residues and the sequence and linkage positions of the oligosaccharide can be obtained by employing a variety of one- and two-dimensional NMR techniques and molecular modeling. These techniques are also useful in establishing the solution conformation of the oligosaccharide moiety. This study is focused on the elucidation of linkage positions of synthetic trisaccharides, Gal(β1-4)Glc(β1-3)Glc, Gal(β1-4)Glc(β1-4)Glc and Gal(β1-4)Glc(β1-6)Glc.

MOLECULAR NUCLEAR IMAGING FOR TARGETING AND TRAFFICKING

  • Bom Hee-Seung;Min Jung-Jun;Jeong Hwan-Jeong
    • Nuclear Engineering and Technology
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    • v.38 no.5
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    • pp.399-404
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    • 2006
  • Noninvasive molecular targeting in living subjects is highly demanded for better understanding of such diverse topics as the efficient delivery of drugs, genes, or radionuclides for the diagnosis or treatment of diseases. Progress in molecular biology, genetic engineering and polymer chemistry provides various tools to target molecules and cells in vivo. We used chitosan as a polymer, and $^{99m}Tc$ as a radionuclide. We developed $^{99m}Tc-galactosylated$ chitosan to target asialoglycoprotein receptors for nuclear imaging. We also developed $^{99m}Tc-HYNIC-chitosan-transferrin$ to target inflammatory cells, which was more effective than $^{67}Ga-citrate$ for imaging inflammatory lesions. For an effective delivery of molecules, a longer circulation time is needed. We found that around 10% PEGylation was most effective to prolong the circulation time of liposomes for nuclear imaging of $^{99m}Tc-HMPAO-labeled$ liposomes in rats. Using various characteristics of molecules, we can deliver drugs into targets more effectively. We found that $^{99m}Tc-labeled$ biodegradable pullulan-derivatives are retained in tumor tissue in response to extracellular ion-strength. For the trafficking of various cells or bacteria in an intact animal, we used optical imaging techniques or radiolabeled cells. We monitored tumor-targeting bacteria by bioluminescent imaging techniques, dentritic cells by radiolabeling and neuronal stem cells by sodium-iodide symporter reporter gene imaging. In summary, we introduced recent achievements of molecular nuclear imaging technologies in targeting receptors for hepatocyte or inflammatory cells and in trafficking bacterial, immune and stem cells using molecular nuclear imaging techniques.

Molecular methods for diagnosis of microbial pathogens in muga silkworm, Antheraea assamensis Helfer (Lepidoptera: Saturniidae)

  • Gangavarapu Subrahmanyam;Kangayam M. Ponnuvel;Kallare P Arunkumar;Kamidi Rahul;S. Manthira Moorthy;Vankadara Sivaprasad
    • International Journal of Industrial Entomology and Biomaterials
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    • v.47 no.1
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    • pp.1-11
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    • 2023
  • The Indian golden muga silkworm, Antheraea assamensis Helfer is an economically important wild silkworm endemic to Northeastern part of India. In recent years, climate change has posed a threat to muga silk production due to the requirement that larvae be reared outdoors. Since the muga silkworm larvae are exposed to the vagaries of nature, the changing climate has increased the incidence of microbial diseases in the rearing fields. Accurate diagnosis of the disease causing pathogens and its associated epidemiology are prerequisites to manage the diseases in the rearing field. Although conventional microbial culturing methods are widely used to identify pathogenic bacteria, they would not provide meaningful information on a wide variety of silkworm pathogens. The information on use of molecular diagnostic tools in detection of microbial pathogens of wild silk moths is very limited. A wide range of molecular and immunodiagnostic techniques including denaturing gradient gel electrophoresis (DGGE), random amplified polymorphism (RAPD), 16S rRNA/ITSA gene sequencing, multiplex polymerase chain reaction (M-PCR), fluorescence in situ hybridization (FISH), immunofluorescence, and repetitive-element PCR (Rep-PCR), have been used for detecting and characterizing the pathogens of insects with economic significance. Nevertheless, the application of these molecular tools for detecting and typing entomopathogens in surveillance studies of muga silkworm rearing is very limited. Here, we discuss the possible application of these molecular techniques, their advantages and major limitations. These methods show promise in better management of diseases in muga ecosystem.

Genetics and Molecular Biology in Aquaculture - Review -

  • Lakra, W.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.14 no.6
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    • pp.894-898
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    • 2001
  • Genetics has played a pivotal role in increasing the world food production through revolutions in plant and animal sciences. Though the attention on fisheries has been inadequate but the growing importance of modern genetic manipulations and biotechnological innovations to aquaculture has been realized. Recent advances in fish genetics and molecular biology have provided a suite of useful techniques, which have several applications in aquaculture. This paper reviews the advancement in the applications of selection, hybridization, chromosome engineering, sex control, gene transfer and molecular technologies for enhanced aquaculture productivity.