Structural Properties Research Articles

Arabic gum-grafted-polyaniline@MnFe2O4/UIO66-NH2 bionanocomposite as adsorbent for quercetin antioxidant: Efficiency, kinetics, thermodynamics and isotherm modelling

Quercetin is one of the most powerful antioxidants in nature and a major dietary flavonoid, so its efficient recovery by nanoadsorbents can be valuable for human health. In this study, the nanocomposite Arabic gum-grafted-polyaniline@MnFe2O4/UIO66-NH2 (AG-g-PANI@MnFe2O4/UIO66-NH2) was synthesized by in situ copolymerization. The physicochemical and structural properties of the AG-g-PANI@MnFe2O4/UIO66-NH2 nanocomposite were examined using various methods, including XRD, FE-SEM, FT-IR, EDX, VSM, TGA, and BET. The adsorption capacity of natural nanoadsorbent was evaluated for the adsorption of quercetin antioxidant from an ethanol-water solution (50 % v/v) in a batch system. The influence of controlling factors such as solution pH, adsorbent dose, contact time, initial quercetin concentration and temperature on the adsorption process was investigated. The highest adsorption capacity (9.1157 mg.g−1) was achieved at a pH of 8, with 0.025 g of adsorbent, a quercetin solution concentration of 20 mg.L−1, a 300 min contact time and at the temperature 298.15 K. In addition, the data from adsorption experiments were analyzed using different isotherm and kinetic models. The findings demonstrated that the Temkin isotherm and the pseudo-second-order kinetic model are the most suitable for representing the adsorption behavior. In addition, from analysis of the temperature effect was found that the adsorption of quercetin on AG-g-PANI@MnFe2O4/UIO66-NH2 is a spontaneous (∆G° < 0) and exothermic (ΔH° < 0) process. Finally, the reusability of nanoadsorbent and desorption kinetics of quercetin were investigated and it was specified that AG-g-PANI@MnFe2O4/UIO66-NH2 can be effectively renewed and recycled, maintaining its adsorption efficacy without significant reduction after five repeated cycles.

“Investigating impact of Ni-Cd substitution on structural magnetic and optical properties of nanosize Al ferrites”

Ferrites are among the most extensively studied materials, specifically due to their amazing and diverse characteristics. Therefore, we synthesized NixCd1-xAlyFe2-yO4 (NCAF) ferrites using a microwave auto-combustion process, with x varying from 0.0 to 1.0 and y set at 0.1. We conducted a meticulous characterization of their structural, surface morphological, magnetic, molecular vibrational and optical properties. X-ray diffraction confirms the lattice parameter and a single-phase spinel structure. Rietveld refined XRD patterns identified the Fd-3m space group cubic spinel phase. HR-TEM examination shows pseudo-spherical particles with an average size of 40–45 nm. Surface topography exhibits tiny, spherical microstructures. The lognormal histogram showed an average particle size of 56.6 nm–124.8 nm, decreasing with nickel concentration. At a nickel concentration (x) of 0.6, saturation magnetization (Ms) increases and then decreases at 1.0. FTIR confirms no organic phase and spinel development. Absorption measurements determined the band gap energy, which Tauc plot revealed to be 2.5870–2.1657 eV. We used the Kubelka-Munk function to find the band gap energy in the UV–Vis diffuse reflectance spectra (DRS), which was between 2.0027 and 1.6817 eV.

Vanadium incorporation in 2D-layered MoSe2.

Recent advances in experimental techniques have made it possible to manipulate the structural and electronic properties of two-dimensional layered materials (2DM) through interaction with foreign atoms. Using quantum mechanics calculations based on the Density Functional Theory (DFT), we explored the dependency of the structural, energetic, electronic, and magnetic properties of the interaction between Vanidium (V) atoms and monolayer (ML) and bilayer (BL) \ce{MoSe2}. The spin-polarized metallic behavior was observed for high V concentration, and a semiconductor/metal interface emerged due to V adsorption on top of BL \ce{MoSe2}.&#xD;Our research demonstrated that the functionalization of 2D materials makes an important contribution to the design of spintronic devices based on a 2D-layered materials platform.

The preparation and construction of biomimetic mineralization compatible interface of wood fiber/foamed magnesium oxychloride lightweight composites

The purpose of this study is to improve the application performance of foamed magnesium oxychloride cement (FMOC) and solve the problem of poor interfacial compatibility between the organic-inorganic interface of traditional inorganic composite materials. Inspired by the adhesion mechanism of barnacles to inorganic substrates through amyloid nanofibers and phosphoprotein, a simple green method was proposed to improve the strength and water resistance of the system. The FMOC composites (30×30×30 mm) were prepared by adding wood flour (WF) and phytic acid (PA) to the mixture of magnesium oxide and magnesium chloride. The influences of WF and PA on the compressive strength, composition, microstructure, pore structure, water resistance and flame retardant properties of FMOC were investigated. WF was used as a skeleton structure to induce cement particle aggregation, the PA molecule was used as a connecting bridge to activate the fiber skeleton to increase the active sites, and promote crystal nucleation and aggregation through hydrogen and ionic bond interactions to construct the biomimetic mineralized structure. The results show that the introduction of PA improves the compressive strength and water resistance of the FMOC/WF/PA composite system. When the PA addition amount is 0.8 %, the compressive strength of FMOC/WF/PA-0.8 % composites reached 6.64 MPa, which was 3 times compared to the FMOC composites. The softening coefficient and water absorption of the obtained FMOC/WF/PA-0.8 % composites were 0.81 and 13.84 %, respectively, which were superior to FMOC composites and presented better behavior in water resistance. Meanwhile, the modified composites have more stable pore structure and flame retardant properties, thus these green FMOC/WF/PA composites displayed potential application value in building energy conservation, aerospace and other fields.

Target Controllability: a Feed-Forward Greedy Algorithm in Complex Networks, Meeting Kalman's Rank Condition.

The concept of controllability within complex networks is pivotal in determining the minimal set of driver vertices required for the exertion of external signals, thereby enabling control over the entire network's vertices. Target controllability further refines this concept by focusing on a subset of vertices within the network as the specific targets for control, both of which are known to be NP-hard problems. Crucially, the effectiveness of the driver set in achieving control of the network is contingent upon satisfying a specific rank condition, as introduced by Kalman. On the other hand, structural controllability provides a complementary approach to understanding network control, emphasizing the identification of driver vertices based on the network's structural properties. However, in structural controllability approaches, the Kalman condition may not always be satisfied. In this study, we address the challenge of target controllability by proposing a feed-forward greedy algorithm designed to efficiently handle large networks while meeting the Kalman controllability rank condition. We further enhance our method's efficacy by integrating it with Barabasi et al.'s structural controllability approach. This integration allows for a more comprehensive control strategy, leveraging both the dynamical requirements specified by Kalman's rank condition and the structural properties of the network. Empirical evaluation across various network topologies demonstrates the superior performance of our algorithms compared to existing methods, consistently requiring fewer driver vertices for effective control. Additionally, our method's application to protein-protein interaction networks associated with breast cancer reveals potential drug repurposing candidates, underscoring its biomedical relevance. This study highlights the importance of addressing both structural and dynamical aspects of network controllability for advancing control strategies in complex systems. The source code is available for free at: Https://github.com/fatemeKhezry/targetControllability. Supplementary data are available at Bioinformatics online.

Theoretical aspects of structure, electronic, optical and elastic properties of Ca(1-x)CxSe mixed alloys in binary and ternary phases

The structural, optoelectronic, and elastic properties of Carbon doped Calcium Selenide binary and ternary semiconductor alloys with the general form of Ca(1-x)CxSe, 0 ≤ x ≤ 1 in B1 and B3 phases have been scrutinized adopting augmented plane wave plus local orbital methods within density functional theory applying different approximations like the Local density approximation (LDA), Wu-Cohen-Generalized Gradients Approximation (WC-GGA) and modified Becke-Johnson (mBJ). Structural properties summarize the crystal structure, relevant atomic positions, lattice constant, Bulk modulus B0, minimum energy E0, and minimum volume V0. Elastic constants confirm the structure stability of the B1 and B3 phases. The band gap was modified from a wider for appropriate optoelectronic devices application to narrow that enhanced the range of applicability of these binary and ternary semiconductor compounds for optoelectronic device applications. Whereas optical properties which include the study of zero frequency limit of static dielectric constant ε0(ω) with its real and imaginary parts, static refractive index n(0), optical reflectivity R(ω), optical absorption coefficient α(ω), optical conductivity σ(ω), and loss function L(ω) studied comprehensively to get real electrical and optical properties of these materials and give semiconductor market best alternative candidate which shows its effectiveness in the visible, ultraviolet and infrared region of the electromagnetic spectrum. Obtained results compared together and with the available experimental along with theoretical work on these binary and ternary Carbon-doped Alkaline earth Selenide.

Effects of the Amyotrophic Lateral Sclerosis-related Q108P Mutation on the Structural Ensemble Characteristics of CHCHD10.

The Q108P pathological variant of the mitochondrial Coiled-Coil-Helix-- Coiled-Coil-Helix Domain-Containing Protein 10 (CHCHD10) has been implicated in amyotrophic lateral sclerosis (ALS). Both the wild-type and CHCHD10Q108P proteins exhibit intrinsically disordered regions, posing challenges for structural studies with conventional experimental tools. This study presents the foundational characterization of the structural features of CHCHD10Q108P and compares them with those of the wild-type counterpart. We conducted multiple run molecular dynamics simulations and bioinformatics analyses. Our findings reveal distinct differences in structural properties, free energy surfaces, and the outputs of principal component analysis between these two proteins. These results contribute significantly to the comprehension of CHCHD10 and its Q108P variant in terms of pathology, biochemistry, and structural biology. The reported structural properties hold promise for informing the development of more effective treatments for ALS.

New design of operational MEMS bridges for measurements of properties of FEBID-based nanostructures.

Focused electron beam-induced deposition (FEBID) is a novel technique for the development of multimaterial nanostructures. More importantly, it is applicable to the fabrication of free-standing nanostructures. Experimenting at the nanoscale requires instruments with sufficient resolution and sensitivity to measure various properties of nanostructures. Such measurements (regardless of the nature of the quantities being measured) are particularly problematic in the case of free-standing nanostructures, whose properties must be separated from the measurement system to avoid possible interference. In this paper, we propose novel devices, namely operational micro-electromechanical system (opMEMS) bridges. These are 3D substrates with nanometer-scale actuation capability and equipped with electrical contacts characterised by leakage resistances above 100 GΩ, which provide a platform for comprehensive measurements of properties (i.e., resistance) of free-standing FEBID structures. We also present a use case scenario in which an opMEMS bridge is used to measure the resistance of a free-standing FEBID nanostructure.

First principles investigation of structural, elastic, thermoelectric, electronic and optical properties XH3 (X=Ac, La) for hydrogen storage

Efficient hydrogen storage is essential for its use as an energy source. Considering the various methods, hydrogen storage in solid materials shows great promise but requires further research. This study employs density functional theory using the Wien2k, with the LSDA method to determine the stability of this storage mode, and LSDA + mBJ to calculate the electronic, optical, and thermoelectric properties of AcH3 and LaH3. The electronic properties reveal that XH3 (X = Ac, La) exhibits a semiconducting nature with indirect energy gaps in both cases. The analysis of hydrogen storage properties determined the gravimetric hydrogen storage capacities for AcH3 and LaH3 to be 1.297 and 2.086 wt%, respectively. Calculations of the elastic constants validated the mechanical stability of these compounds. Thermoelectric characteristics, including electrical and thermal conductivity, Seebeck coefficient, electronic specific heat capacity, and Pauli magnetic susceptibility, have been evaluated, highlighting their p-type characteristics. The figure of merit indicates their potential for thermoelectric devices. Gravimetric ratios suggest significant hydrogen storage capacity, which could contribute to various transportation and energy applications.

Cu-TiO2/Zeolite/PMMA Tablets for Efficient Dye Removal: A Study of Photocatalytic Water Purification

In this study, Cu-doped TiO2 combined with natural zeolite (ZT) was synthesized and applied as a fixed powder layer on poly(methyl methacrylate) (PMMA) tablets. The material’s morphology, structural, and chemical properties were characterized using high-resolution scanning electron microscopy, Raman spectroscopy, and Brunauer–Emmett–Teller analysis. The antioxidant capacity was evaluated by assessing the neutralization of hydroxyl radicals and iron (III) ions. For the first time, tablets with Cu-TiO2 and ZT deposited on PMMA as the carrier were investigated for removing two dyes, methyl orange (MO) and methylene blue (MB), from water under simulated solar (SS) and UVC irradiation. Under SS irradiation, the Cu-TiO2/PMMA and Cu-TiO2/ZT/PMMA tablets achieved about 21% degradation of MB after 240 min. This result is particularly noteworthy because SS radiation provides lower energy compared with UVC, making the process more economically efficient. Furthermore, the photocatalysts are immobilized on a stable carrier, which enhances the method’s cost-effectiveness by reducing material loss and simplifying recovery. In the presence of ZT/PMMA tablets, 69% of MB was removed by adsorption after 240 min. Additionally, we explored the mechanism of degradation, revealing that the enhanced generation of hydroxyl radicals plays a pivotal role in the effective degradation of MB. At the same time, photogenerated holes contribute to the removal of MO. The overall results suggest that the tablets obtained are a promising solution for water purification due to their effectiveness, simplicity, and low processing cost.

Sustainable pseudocapacitance potential of a hybrid triad involving activated carbon derived from polyester wastes

This study introduces an innovative approach to fabricate high-efficiency supercapacitor electrodes by utilizing waste polyester (PES), a common fabric waste, as a precursor for producing activated carbon. This approach not only addresses waste disposal issues but also provides a valuable resource for various environmental and industrial applications. Through a series of chemical and thermal treatments, PES waste is transformed into a porous carbon structure, which is then functionalized with PPy and V2O5 to enhance its electrical conductivity and electrochemical performance. The synthesized composite is characterized by several analytical and spectral techniques to elucidate the morphological, structural and surface properties. The specific surface area of the hybrid composite material is 50.4 m2g−1. Cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy are employed to evaluate the performance of the composites as supercapacitor electrodes. From the CV curves, the electrochemically active surface area was calculated to be 0.085 m2g-1. The composite exhibits a remarkable specific capacitance of 535 Fg-1 and energy as well as power density values of 171 W h Kg−1 and 2877 W Kg−1 respectively at a current density of 2 Ag−1. The material was fabricated into device and was observed to show excellent cycling satbility for up to 10,000 cycles.

Enhanced photocatalytic degradation of organic pollutants by randomly oriented 2D SnS2 nanostructures

Abstract In this study, we present a bottom-up solvothermal technique using tin tetrachloride pentahydrate (SnCl4.5H2O) and thioacetamide as precursors to synthesize SnS2 nanostructures. Different solvents including isopropyl alcohol, ethanol, and ethylene glycol were used in the reaction to enhance the photodegradation efficiency of organic pollutants, Methylene Blue (MB), and Tetracycline (TC) in an aqueous medium under simulated solar light irradiation. The SnS2 nanostructures synthesized with these solvents were characterized using various structural, morphological, and optical techniques, including XRD, RAMAN, FESEM, XPS, UV–Vis, and Brunauer–Emmett–Teller analysis. The choice of solvent was found to significantly affect the structural, morphological, and optical properties of the SnS2 nanostructures. Notably, the sample synthesized with ethanol as the solvent displayed a unique morphology, enhanced light-harvesting ability, efficient charge carrier separation, and a larger specific surface area, all of which contributed to its superior photocatalytic activity. This sample achieved 99.9% degradation of MB and 95% degradation of TC within 20 and 40 minutes, respectively. The kinetic analysis revealed maximum rate constant (k) values of 0.15242 min-1 for MB and 0.06095 min-1 for TC, as determined by the pseudo-first-order kinetic model. We also discuss the plausible mechanism involving visible light-induced electron-hole pairs that generate reactive species, leading to the mineralization of dyes into H2O, CO2, and other gaseous products. The synthesized SnS2 nanostructures demonstrate significant potential for enhanced photocatalytic activity in organic pollutant degradation, underscoring their promise in addressing water pollution challenges.

Insight into Structural, Electronic, Elastic and Optical Properties of Thallium Based Perovskite TlXBr3 (X = Ti, Zr) via DFT Study for Reflective Coating

Insight into Structural, Electronic, Elastic and Optical Properties of Thallium Based Perovskite TlXBr3 (X = Ti, Zr) via DFT Study for Reflective Coating

Effect of β‐nucleating agents on structure and mechanical properties of dynamic crosslinked ethylene‐octene random copolymer/polypropylene and ethylene‐octene block copolymer/polypropylene blends

Effect of β‐nucleating agents on structure and mechanical properties of dynamic crosslinked ethylene‐octene random copolymer/polypropylene and ethylene‐octene block copolymer/polypropylene blends

Characterization and Performance Evaluation of Ni-Doped SnO2 Thin Films for Optoelectronic Applications: Structural, Optical, and Electrical Insights

Abstract Undoped and Ni-doped tin oxide thin films were synthesized using the spray pyrolysis technique on ordinary glass substrates. The study aimed to investigate the physico-chemical properties of these thin films using various characterization techniques. X-ray diffraction analysis revealed a polycrystalline behavior with a tetragonal structure and a preferential orientation along the direction for both undoped and Ni-doped SnO2 films. Raman spectroscopy confirm the tetragonal rutile structure and shows a slight enhancement of crystallinity for 4% Ni doped SnO2 thin films. Optical measurements showed a decrease in transmittance with increasing dopant ratio, indicating reduced transparency, and a decrease in band gap with Ni insertion. Electrical measurements, conducted through I-V curve analysis, confirmed Ohm's law compliance and indicated a decrease in resistivity with Ni doping, suggesting improved electrical conductivity. Additionally, the study explored the performance of thin-film solar cells utilizing SnO2 as a transparent conducting layer through numerical simulations using SCAPS-1D software. The effects of Ni doping on the solar cell performance were examined, suggesting potential enhancements or modifications in efficiency and functionality. Overall, the findings provide valuable insights into the structural, optical, and electrical properties of undoped and Ni-doped SnO2 thin films, offering promising avenues for their application in optoelectronic devices.

First−Principle Study on Electronic Structure and Magnetism in Doped Boron Phosphide Nanosheet

Based on the first‐principles calculation of density‐functional theory, the electronic structure and magnetic properties of hexagonal boron phosphide (h‐BP) with doping and applying strain to the transition‐metal (TM = Cr, Mn, Fe, Co, and Ni) elements are investigated. After the TM elements are introduced, the magnetism is induced. The magnetic moments are 3.00, 3.87, 1.00, 1.99, and 1.00 μB, respectively, which mainly contributed by the 3d orbitals of TM elements. In the case of magnetic coupling, Cr–Cr are mainly coupled antiferromagnetically at different distances. In addition, Fe–Fe performs a ferromagnetic state, and Co–Co represents an antiferromagnetic state with the distance of 3.213 Å. After applied strain, Co doped of the system shows the characteristics of semimetals under the application of 4% strain. It can be added that for h‐BP systems, doping Co and Mn increases its conductivity, which is beneficial to the study of spintronic materials.

Conformational Flexibility and Net Charge are Key Determinants for the Antimicrobial Activity of Peptide Uy234 Against Multidrug-resistant Bacteria

BackgroundThe antimicrobial activity of two peptides, Uy234 derived from the venom of the scorpion Urodacus yaschenkoi and a consensus peptide QnCs-Buap, was evaluated. We tested different pathogenic bacteria: Acinetobacter baumannii, Klebsiella pneumoniae, Salmonella enterica, Bacillus subtilis, Enterococcus spp. and Staphylococcus aureus, including one methicillin resistant (MRSA) and two multidrug resistant (MDR) clinical isolates. In contrast to the QnCs-Buap peptide, Uy234 showed relevant growth inhibitory activity on A. baumannii and B. subtilis, and mostly on S. aureus strains.ObjectiveThe present research focused on elucidating the mechanism for this antibacterial activity.MethodologyWe carried out an in-depth analysis of the composition, structure, flexibility, and physicochemical properties of both peptides.ResultsWe found a crucial role of the C-terminal amide and composition in favoring the formation of a dense H-bond network in the Uy234 peptide. This H-bonding network slightly stiffens the peptide and keeps it in a preordered conformation in the aqueous phase.ConclusionsWe hypothesize that, given that Uy234 is a very short peptide (18 aa), it could have a destabilizing effect and favor micellization phenomena instead forming pores. In contrast, the QnCs-Buap peptide (13 aa), having only the positive charge at the N-terminal end and being significantly more hydrophobic and rigid, is not capable of overcoming the energy barrier to disturb the membrane. We propose that Uy234 peptide can be a scaffold to develop new derivatives with high potential against infections caused by diverse multidrug-resistant bacteria.Graphical

Structural Fluctuation in Homodimeric Aminoacyl-tRNA Synthetases Induces Half-of-the-Sites Activity.

Enzymatic activity is regulated by various mechanisms to ensure biologically proper functions. Notable instances of such regulation in homodimeric enzymes include "all-of-the-sites activity" and "half-of-the-sites activity". The difference in these activities lies in whether one or both of the subunits are simultaneously active. Owing to its uniqueness, the mechanism of half-of-the-sites activity has been widely investigated. Consequently, structural asymmetry derived from cooperative motion is considered to induce half-of-the-sites activity. In contrast, recent investigations have suggested that subunit-intrinsic properties or structural fluctuation also induces structural asymmetry. Hence, the mechanism underlying half-of-the-sites activity has not been completely elucidated. Additionally, most previous studies have focused only on half-of-the-sites activity. Therefore, by comparing the structural and dynamical properties of two representative homodimers exhibiting all-of-the-sites and half-of-the-sites activities, respectively, we attempted to elucidate the mechanism of half-of-the-sites activity. Specifically, all-atom molecular dynamics simulations were applied to lysyl-tRNA synthetase and tyrosyl-tRNA synthetase. Our analysis revealed that structural fluctuation is sufficient to induce structural asymmetry in addition to the well-established factor of cooperative motion. Considering that structural fluctuation is a common characteristic of any enzyme, it could be a general factor in half-of-the-sites activity.

Novel hydrogen-bonded organic frameworks-based coating for fat oil and grease deposition control in the sewer system

Hydrogen-bonded organic frameworks (HOFs) represent an emerging class of porous materials characterized by crystalline frame structures, self-assembled from organic molecules through hydrogen bonding. This study demonstrates that HOFs fragment into small particles while preserving their original structure when dispersed in a polymeric epoxy solution. The intermolecular hydrogen bond structural and electronic properties of the LH4-HOF complex as well as the mechanism of HOF incorporated epoxy were extensively studied using density functional theory. LH4-HOF has a high Langmuir surface area of 2758.3 m2/g and nonlocal density functional theory pore size distributions of 3 A°. This unique solution processability enables the fabrication of coatings with high stability in aqueous systems. Results from a 30-day leaching test under controlled conditions (pH 7, temperature 20 ± 2 °C) indicate that LH4-HOF incorporated epoxy-coated concrete samples exhibited an over 85 % reduction in calcium release compared to uncoated samples, with epoxy-coated samples alone showing a 60 % reduction in calcium leaching. Additionally, the LH4-HOF-incorporated epoxy coating reduced the formation of fats, oils and grease deposits by more than 73 % on the concrete samples. Thus, this novel coating approach offers a sustainable solution with significant potential applications in sewer management.

Graph Curvature Flow-Based Masked Attention.

Graph neural networks (GNNs) have revolutionized drug discovery in chemistry and biology, enhancing efficiency and reducing resource demands. However, classical GNNs often struggle to capture long-range dependencies due to challenges like oversmoothing and oversquashing. Graph Transformers address these issues by employing global self-attention mechanisms that allow direct information exchange between any pair of nodes, enabling the modeling of long-range interactions. Despite this, Graph Transformers often face difficulties in capturing the nuanced structural information on graphs. To overcome these challenges, we introduce the CurvFlow-Transformer, a novel graph Transformer model incorporating a curvature flow-based masked attention mechanism. By leveraging a topologically enhanced mask matrix, the attention layer can effectively detect subtle structural differences within graphs, balancing the focus between global mutual information and local structural details of molecules. The CurvFlow-Transformer demonstrates superior performance on the MoleculeNet data set, surpassing several state-of-the-art models across various tasks. Moreover, the model provides unique insights into the relationship between molecular structure and chemical properties by analyzing the attention heat coefficients of individual atoms.