Design and fabrication of a length-extensional mode rectangular X-cut quartz resonator with zero temperature coefficient.

Rectangular X-cut quartz crystal resonators with cut angles theta > 5.0 degrees and aspect ratios Rzy (= width 2z0/length 2y0) from 0.3 to 0.5 are investigated. The resonators oscillate mode is a length-extensional mode. A semiempirical frequency equation was derived from the stress expressed in terms of the trigonometric and the hyperbolic transcendental functions with constants estimated by the regression curve fit to the stress simulated by the finite-element method (FEM). Contours on which a point satisfies a zero first order temperature coefficient condition are shown in a cut angle theta and Rzy diagram. We proved that a fabricated resonator with Rzy = 0.400 and theta = 16.0 degrees, whose design parameter is located in the area of the contour, had a zero temperature coefficient.     

Triple‐junction effect and its electric field relaxation in three dielectrics

This paper analyzes the electric field distribution near a wedge‐like edge in arrangements consisting of three dielectrics using analytical and numerical methods. The electric potential behaves exponentially as rⁿ (r is the distance from the edge) near the edge, leading to an infinitely high field with decreasing r for all cases. The value of the analytically derived exponent n agreed well with that obtained from the numerical field calculations. It has also been demonstrated that rounded contact of the spacer with a zero contact angle can make the electric field constant without showing an exponential rise near the edge. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 1– 8, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20670     

Pervaporation separation of water/ethanol mixtures through polysaccharide membranes. II. The permselectivity of chitosan membrane

The separation of water/alcohol mixtures through chitosan membrane was investigated. The degree of the deacetylation of chitosan did not affect the selectivity of the membrane in the separation of the water/ethanol mixture. The selectivity of the chitosan membrane was affected by the specific salts such as CoSO₄, ZnSO₄, and MnSO₄ and it increased when the salts were present in the feed mixture or the membrane was pretreated with the salt solution. This behavior would be explained by the contraction of the “holes” produced by the thermal motion of polymer chains and this contraction would be correlated with the conformation change of chitosan molecule due to the formation of complexes with metal ions.     

Preparation of fine polymer particles containing metallocene derivatives

This article deals with preparations of fine particles of metallocene copolymers by emulsifierfree emulsion polymerization of vinylferrocene (VFc), ferrocenylmethyl methacrylate (FMMA), 1-ferrocenylethyl methacrylate (1-FEMA), 2-ferrocenylethyl methacrylate (2-FEMA), and 1-ruthenocenylethyl methacrylate (1-REMA) with acrylonitrile (AN), styrene (St), and methyl methacrylate (MMA) in water/ethanol medium. As a result, spherical copolymer particles containing metallocene derivatives have been successfully synthesized in the particle size of ca. 120 to 600 nm. The contents of ferrocenyl or ruthenocenyl groups in copolymer particles increased with increasing concentration of charged metallocene derivatives, while the amounts of metallocene derivatives incorporated into particles are much lower than the charged ratio. © 1994 John Wiley & Sons, Inc.     

Enhanced antiviral activity of soybean β-conglycinin-derived peptides by acylation with saturated fatty acids

Abstract: Peptide mixtures prepared from soybean β‐conglycinin (7S‐peptides) were acylated with saturated fatty acids of different chain length (6C‐18C) in order to improve their antiviral activity against Feline calicivirus (FCV) strain F9 which is a typical norovirus surrogate. Among the fatty acids varieties, it was revealed that 7S‐peptides acylated with myristic and palmitic acids potently inhibited FCV replication. Myristorylation and palmitoylation of 7S‐peptides kept host cells viability at 91.51% and 98.90%, respectively. The infectivity of FCV on Crandell–Reese feline kidney cells was further determined after exposure of initial titer of 10^6.47 TCID₅₀/mL. Myristoylated and palmitoylated 7S‐peptides significantly (P < 0.006) reduced FCV infectivity as compared to native 7S‐peptides. Native 7S‐peptides showed 25% FCV inhibitory activity while myristoylated and palmitoylated 7S‐peptides exhibited 98.59% and 99.98% reduction in FCV infectivity, respectively. Myristoylated and palmitoylated 7S‐peptides demonstrated higher anti‐FCV activity in a wide range of concentration with complete reduction at 25 μg/mL. Surface hydrophobicity was significantly (P < 0.05) increased after attachment of long hydrocarbon fatty acids to 7S‐peptides as supported by changes in fluorescence intensity. Enzymatic hydrolysis together with acylation will give an insight into surface and physiological functional lipopeptides derived from soy β‐conglycinin.     

Bubble behavior in vertical tube banks installed in a fluidized bed

Fluidized bed combustion is one of the advantageous technologies for coal and/or incineration firing especially with respect to the environmental protection of emissions, such as NO_x/SO_x. Bed material movement in such a fluidized bed has a prime importance in the heat transfer process. Thus, quantitative measurement of the bed material movement and the void fraction are indispensable for better understanding of the fluidized bed. In this investigation, neutron radiography is applied to visualize the bed material movement in a simulated fluidized bed heat exchanger installed with vertical tubes. Bubble behavior and void fraction profile are obtained by the image processing technique. Bubble movement is highly restrained by these vertical tubes, so that the bubbles rise up along the tube. The bubble diameter is well correlated by the modified Mori and Wen's correlation taking into account the pitch of the tube arrangement. The bubble rise velocity and void fraction are well correlated by applying the drift‐flux model. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 727–739, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10127     

Origin of electron mobility enhancement in (1 1 1)-oriented InGaAs channel metal-insulator-semiconductor field-effect-transistors

Electrical and physical characteristics of the Al₂O₃/InGaAs interfaces with (1 1 1)A and (1 0 0) orientations were investigated in an attempt to understand the origin of electron mobility enhancement in the (1 1 1)A-channel metal-insulator-semiconductor field-effect-transistor. The (1 1 1)A interface has less As atoms of high oxidation states as probed by X-ray photoelectron spectroscopy. The electrical measurements showed that energy distribution of the interface traps for the (1 1 1)A interface is shifted toward the conduction band as compared to that for the (1 0 0) interface. Laterally-compressed cross-section transmission electron microscopy images showed that the characteristic lengths of the interface roughness are different between the (1 1 1)A and (1 0 0) interfaces. The contributions of the Coulomb and roughness scattering mechanisms are discussed based on the experimental results.     

State-of-the-Art Molecular Dynamics Simulation Studies of RNA-Dependent RNA Polymerase of SARS-CoV-2

Molecular dynamics (MD) simulations are powerful theoretical methods that can reveal biomolecular properties, such as structure, fluctuations, and ligand binding, at the level of atomic detail. In this review article, recent MD simulation studies on these biomolecular properties of the RNA-dependent RNA polymerase (RdRp), which is a multidomain protein, of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are presented. Although the tertiary structures of RdRps in SARS-CoV-2 and SARS-CoV are almost identical, the RNA synthesis activity of RdRp of SARS-CoV is higher than SARS-CoV-2. Recent MD simulations observed a difference in the dynamic properties of the two RdRps, which may cause activity differences. RdRp is also a drug target for Coronavirus disease 2019 (COVID-19). Nucleotide analogs, such as remdesivir and favipiravir, are considered to be taken up by RdRp and inhibit RNA replication. Recent MD simulations revealed the recognition mechanism of RdRp for these drug molecules and adenosine triphosphate (ATP). The ligand-recognition ability of RdRp decreases in the order of remdesivir, favipiravir, and ATP. As a typical recognition process, it was found that several lysine residues of RdRp transfer these ligand molecules to the binding site such as a “bucket brigade.” This finding will contribute to understanding the mechanism of the efficient ligand recognition by RdRp. In addition, various simulation studies on the complexes of SARS-CoV-2 RdRp with several nucleotide analogs are reviewed, and the molecular mechanisms by which these compounds inhibit the function of RdRp are discussed. The simulation studies presented in this review will provide useful insights into how nucleotide analogs are recognized by RdRp and inhibit the RNA replication.     

MC180295 Inhibited Epstein–Barr Virus-Associated Gastric Carcinoma Cell Growth by Suppressing DNA Repair and the Cell Cycle

DNA methylation of both viral and host DNA is one of the major mechanisms involved in the development of Epstein–Barr virus-associated gastric carcinoma (EBVaGC); thus, epigenetic treatment using demethylating agents would seem to be promising. We have verified the effect of {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295, which was discovered by screening for demethylating agents. {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295 inhibited cell growth of the EBVaGC cell lines YCCEL1 and SNU719 in a dose-dependent manner. In a cell cycle analysis, growth arrest and apoptosis were observed in both YCCEL1 and SNU719 cells treated with {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295. MKN28 cells infected with EBV were sensitive to {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295 and showed more significant inhibition of cell growth compared to controls without EBV infection. Serial analysis of gene expression analysis showed the expression of genes belonging to the role of BRCA1 in DNA damage response and cell cycle control chromosomal replication to be significantly reduced after {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295 treatment. We confirmed with quantitative PCR that the expression levels of BRCA2, FANCM, RAD51, TOP2A, and CDC45 were significantly decreased by {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295. LMP1 and BZLF1 are EBV genes with expression that is epigenetically regulated, and {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295 could up-regulate their expression. In conclusion, {"type":"entrez-nucleotide","attrs":{"text":"MC180295","term_id":"1885105835","term_text":"MC180295"}}MC180295 inhibited the growth of EBVaGC cells by suppressing DNA repair and the cell cycle.