• Title/Summary/Keyword: Molecular Flow

Search Result 890, Processing Time 0.023 seconds

Molecular Dynamics Study for Improving the Adhesion of Paint (도료의 부착성 개선을 위한 분자동역학적 연구)

  • Yang, Young-Joon;Lee, Chi-Woo
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.31 no.8
    • /
    • pp.932-938
    • /
    • 2007
  • The interaction between adherent molecules and gas molecules was modeled in molecular scale and simulated by the molecular dynamics method in order to understand the evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantify and gas molecular collisions because the industrial oil has too complex structures of fatty acid. The effects of adherent quantify, gas temperature and surface temperature for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on surface temperature shown in the experimental results.

MOLECULAR SCALE MECHANISM ON EVAPORATION AND REMOVAL PROCESS OF ADHERENT MOLECULES ON SURFACE BY BURNT GAS

  • Yang, Y.J.;Lee, C.W.;Kadosaka, O.;Shibahara, M.;Katsuki, M.;Kim, S.P.
    • International Journal of Automotive Technology
    • /
    • v.7 no.2
    • /
    • pp.121-128
    • /
    • 2006
  • The interaction between adherent molecules and gas molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantity and gas molecular collisions because the industrial oil has too complex structures of fatty acid. Effects of adherent quantity, gas temperature, surface temperature and adhesion strength for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on the surface temperature shown in the experimental results.

Multiparameter Flow Cytometry: Advances in High Resolution Analysis

  • O'Donnell, Erika A.;Ernst, David N.;Hingorani, Ravi
    • IMMUNE NETWORK
    • /
    • v.13 no.2
    • /
    • pp.43-54
    • /
    • 2013
  • Over the past 40 years, flow cytometry has emerged as a leading, application-rich technology that supports high-resolution characterization of individual cells which function in complex cellular networks such as the immune system. This brief overview highlights advances in multiparameter flow cytometric technologies and reagent applications for characterization and functional analysis of cells modulating the immune network. These advances significantly support highthroughput and high-content analyses and enable an integrated understanding of the cellular and molecular interactions that underlie complex biological systems.

Associations Between Age, Cytogenetics, FLT3-ITD, and Marrow Leukemia Cells Identified by Flow Cytometry

  • Su, Long;Gao, Su-Jun;Tan, Ye-Hui;Han, Wei;Li, Wei
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.9
    • /
    • pp.5341-5344
    • /
    • 2013
  • Objectives: To explore the relationships between age, cytogenetic subgroups, molecular markers, and cells with leukemic aberrant immunophenotype in patients with acute myeloid leukemia (AML). Methods: In this study, we evaluated the correlations between age, cytogenetic subgroups (normal, balanced and unbalance karyotype), molecular mutations (NPM1, FLT3-ITD, and CEBPA mutations) and marrow leukemia cells (LC) identified by flow cytometry in 256 patients with de novo AML. Results: From age group 10-19 years to age group ${\geq}60$ years, the percentage of LC decreased from $67.0{\pm}18.4%$ to $49.0{\pm}25.1%$ (F=2.353, P=0.041). LC percentage was higher in patients with balanced karyotypes ($65.7{\pm}22.4%$), than those with unbalanced karyotypes ($46.0{\pm}26.6%$) (u=3.444, P=0.001) or a normal karyotype ($49.9{\pm}22.1%$) (u=5.093, P<0.001). Patients with FLT3-ITD ($64.3{\pm}19.5%$) had higher LC percentages compared with those without ($54.2{\pm}24.3%$) (u=2.794, P=0.007). Conclusions: Associations between age, cytogenetics, molecular markers, and marrow leukemia cells may offer beneficial information to understand the biology and pathogenesis of AML.

Bacterial Surface Display of $GFP_{UV}$ on Bacillus subtilis Spores

  • Kim, Jung-Hyung;Roh, Chang-Hyun;Lee, Chang-Won;Kyung, Do-Hyun;Choi, Soo-Keun;Jung, Heung-Chae;Pan, Jae-Gu;Kim, Byung-Gee
    • Journal of Microbiology and Biotechnology
    • /
    • v.17 no.4
    • /
    • pp.677-680
    • /
    • 2007
  • To analyze a cotG-based Bacillus subtilis spore display system directly, $GFP_{UV}$ was expressed on the surface of Bacillus subtilis spores. When $GFP_{UV}$ was fused to the C-terminal of the cotG structural gene and expressed, the existence of a $CotG-GFP_{UV}$ fusion protein on the B. subtilis spore was confirmed by flow cytometry confocal microscopic analysis. When the cotG anchoring motif was deleted, no fluorescence emission was observed under flow cytometry and confocal microscopic analysis from the purified spore, confirming the essential role of CotG as an anchoring motif. This $GFP_{UV}$ displaying spore might be used for another signaling application triggered by intracellular or extracellular stimuli.

A Study of the numerical method on the molecular transition flow for the rotating blades (회전날개주위 분자천이유동의 수치해석방법에 관한 연구)

  • 허중식;황영규;박종윤
    • Journal of the Korean Vacuum Society
    • /
    • v.8 no.2
    • /
    • pp.83-92
    • /
    • 1999
  • Pumping performance of a disk-type molecular drag pump for a hybrid molecular pump is numerically analyzed by the direct simulation onte-Carlo method. The flows in pumping channels are three-dimensional (3D) in a molecular transition regime. The main difficulty in modeling a 3D case comes from the rotating frame of reference. Thus, trajectories of particles ar no longer straight lines. In the present study, trajectories of particles are calculated by integrating a system of differential equations including the Coriolis and centrifugal forces. The null-collisions. The present numerical results molecular model is used for calculation of molecular collisions. The present numerical results significantly disagree with the previously known ones. This indicates that an actual pumping passage is very limited to a narrow region due to the significant backstreaming of molecules from the outlet.

  • PDF

Dynamic Viscoelastic Properties of Aqueous Poly(Ethylene Oxide) Solutions (폴리에틸렌옥사이드 수용액의 동적 점탄성)

  • Song, Ki-Won;Bae, Jun-Woong;Chang, Gap-Shik;Noh, Dong-Hyun;Park, Yung-Hoon;Lee, Chi-Ho
    • Journal of Pharmaceutical Investigation
    • /
    • v.29 no.4
    • /
    • pp.295-307
    • /
    • 1999
  • Using a Rheometries Fluids Spectrometer (RFS II), the dynamic viscoelastic properties of aqueous poly(ethylene oxide) (PEO) solutions in small amplitude oscillatory shear flow fields have been measured over a wide range of angular frequencies. The angular frequency dependence of the storage and loss moduli at various molecular weights and concentrations was reported in detail, and the result was interpreted using the concept of a Deborah number De. In addition, the experimentally determined critical angular frequency at which the storage and loss moduli become equivalent was compared with the calculated characteristic time (or its inverse value), and their physical significance in analyzing the dynamic viscoelastic behavior was discussed. Finally, the relationship between steady shear flow and dynamic viscoelstic properties was examined by evaluating the applicability of some proposed models that describe the correlations between steady flow viscosity and dynamic viscosity, dynamic fluidity, and complex viscosity. Main results obtained from this study can be summarized as follows: (1) At lower angular frequencies where De<1, the loss modulus is larger than the storage modulus. However, such a relation between the two moduli is reversed at higher angular frequencies where De>l, indicating that the elastic behavior becomes dominant to the viscous behavior at frequency range higher than a critical angular frequency. (2) A critical angular frequency is decreased as an increase in concentration and/or molecular weight. Both the viscous and elastic properties show a stronger dependence on the molecular weight than on the concentration. (3) A characteristic time is increased with increasing concentration and/or molecular weight. The power-law relationship holds between the inverse value of a characteristic time and a critical angular frequency. (4) Among the previously proposed models, the Cox-Merz rule implying the equivalence between the steady flow viscosity and the magnitude of the complex viscosity has the best validity. The Osaki relation can be regarded to some extent as a suitable model. However, the DeWitt, Pao and HusebyBlyler models are not applicable to describe the correlations between steady shear flow and dynamic viscoelastic properties.

  • PDF

Effect of propofol on salivary secretion from the submandibular, sublingual, and labial glands during intravenous sedation

  • Keisuke Masuda;Akira Furuyama;Kenji Ohsuga;Shota Abe;Hiroyoshi Kawaai
    • Journal of Dental Anesthesia and Pain Medicine
    • /
    • v.23 no.3
    • /
    • pp.153-162
    • /
    • 2023
  • Background: Recent animal studies have suggested the role of GABA type A (GABA-A) receptors in salivation, showing that GABA-A receptor agonists inhibit salivary secretion. This study aimed to evaluate the effects of propofol (a GABA-A agonist) on salivary secretions from the submandibular, sublingual, and labial glands during intravenous sedation in healthy volunteers. Methods: Twenty healthy male volunteers participated in the study. They received a loading dose of propofol 6 mg/kg/h for 10 min, followed by 3 mg/kg/h for 15 min. Salivary flow rates in the submandibular, sublingual, and labial glands were measured before, during, and after propofol infusion, and amylase activity was measured in the saliva from the submandibular and sublingual glands. Results: We found that the salivary flow rates in the submandibular, sublingual, and labial glands significantly decreased during intravenous sedation with propofol (P < 0.01). Similarly, amylase activity in the saliva from the submandibular and sublingual glands was significantly decreased (P < 0.01). Conclusion: It can be concluded that intravenous sedation with propofol decreases salivary secretion in the submandibular, sublingual, and labial glands via the GABA-A receptor. These results may be useful for dental treatment when desalivation is necessary.

Shear Stress and Atherosclerosis

  • Heo, Kyung-Sun;Fujiwara, Keigi;Abe, Jun-Ichi
    • Molecules and Cells
    • /
    • v.37 no.6
    • /
    • pp.435-440
    • /
    • 2014
  • Hemodynamic shear stress, the frictional force acting on vascular endothelial cells, is crucial for endothelial homeostasis under normal physiological conditions. When discussing blood flow effects on various forms of endothelial (dys)function, one considers two flow patterns: steady laminar flow and disturbed flow because endothelial cells respond differently to these flow types both in vivo and in vitro. Laminar flow which exerts steady laminar shear stress is atheroprotective while disturbed flow creates an atheroprone environment. Emerging evidence has provided new insights into the cellular mechanisms of flowdependent regulation of vascular function that leads to cardiovascular events such as atherosclerosis, atherothrombosis, and myocardial infarction. In order to study effects of shear stress and different types of flow, various models have been used. In this review, we will summarize our current views on how disturbed flow-mediated signaling pathways are involved in the development of atherosclerosis.