The dielectric properties of the galactose-binding lectins Bauhinia monandra (BmoLL) and Concanavalin A (Con A) were assessed by surface potential measurements of their spread monolayers on an aqueous subphase containing a monovalent electrolyte. For both lectins the curves of surface potential versus mean molecular area (DeltaV-A) and the independently recorded isotherms of surface pressure versus mean molecular area (Pi-A) were shown to be pH-dependent. As the subphase pH changed from 2 to 9, a noticeable trend to higher surface pressures accompanied the compression of the monolayers. Conversely, the surface potentials values of both monolayers decreased with increasing pH. For Con A, with the single exception of the pH 9 case, lowering the pH yielded DeltaV values higher than those for BmoLL. The contribution of the electric double layer (Psi0) to the overall DeltaV values at a given Pi (15 mN/m) was calculated using a modified Davies equation and assuming that at this surface pressure the monolayers of both studied lectins were stable. While at all studied pHs the Psi0 values for Con A exceeded those calculated for BmoLL, for both lectins they were insensitive to pH changes. This provided evidence that the reorientation of lectin molecules, during compression predominantly contributed to the alteration of the overall DeltaV values. The calculated Psi0 values made possible the evaluation of the dipole moments for BmoLL and Con A, and it has been estimated that the decrease in the pH of the subphase from 9 to 2 produced a 1.6-fold (twofold) increase in the value of for BmoLL (Con A). The differences in dielectric properties between the two film-forming lectins have been attributed to the differences in their structures. Indeed, the circular dichroism (CD) spectrum of Con A showed the predominance of beta-plated sheet structures while that of BmoLL was typically rich in alpha-helix structures.
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http://dx.doi.org/10.1016/j.jcis.2005.01.076 | DOI Listing |
R Soc Open Sci
January 2025
Institute of Southeast Vietnamese Studies, Thu Dau Mot University, Thu Dau Mot, Binh Duong, Vietnam.
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Department of Physics, University of Kerala, Karyavattom 695581, Thiruvananthapuram, Kerala, India.
The effects of Na doping on the structure magnetic, electric, and magnetoelectric properties of GaFeOwere studied. Rietveld refinement of the XRD data reveals the formation of a single-phase trigonal structure with no impurity on Na doping up to 50% and a significant increase in lattice strain with doping. FTIR and Raman analysis further supported the phase purity of the samples.
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January 2025
Laboratory of Advanced Materials, Institute of Optoelectronics, Fudan University, Shanghai, 200438, P. R. China.
Metal single atoms (SA)-support interactions inherently exhibit significant electrochemical activity, demonstrating potential in energy catalysis. However, leveraging these interactions to modulate electronic properties and extend application fields is a formidable challenge, demanding in-depth understanding and quantitative control of atomic-scale interactions. Herein, in situ, off-axis electron holography technique is utilized to directly visualize the interactions between SAs and the graphene surface.
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Department of Electrical and Software Engineering, University of Calgary, Calgary, Alberta, Canada.
Readily available animal tissue, such as ground beef, is a convenient material to represent the dielectric properties of biological tissue when validating microwave imaging and sensing hardware and techniques. The reliable use of these materials depends on the accurate characterization of their properties. In this work, the effect of physiologically relevant levels of dehydration on ex vivo tissue samples is quantified while controlling for variation within and between samples.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Physics, Bangladesh University of Engineering and Technology (BUET), Dhaka, Bangladesh.
High dielectric constants with less dielectric loss composites is highly demandable for technological advancements across various fields, including energy storage, sensing, and telecommunications. Their significance lies in their ability to enhance the performance and efficiency of a wide range of devices and systems. In this work, the dielectric performance of graphene oxide (GO) reinforced plasticized starch (PS) nanocomposites (PS/GO) for different concentrations of GO nanofiller was studied.
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