Investigation Of Structure Research Articles

Review of actinide core-level photoemission

Photoelectron spectroscopy allows for the investigation of the electronic structure and chemical bonding of actinide elements and their compounds, providing insights into oxidation states, chemical environments, and electronic configurations. This knowledge can aid in comprehending reactivity, stability, and other properties of actinide materials, which is essential for ensuring safe handling, storage, and disposal in nuclear applications. We have reviewed a number of results in actinide core-level photoemission studies, with a particular focus on x-ray photoemission spectroscopy (XPS) techniques. Actinides, due to their inherent radioactivity, have not been as well studied with XPS as have other segments of the periodic table. Given the inherent safety concerns, equipment requirements, and short isotopic lifetimes associated with actinide research, we outline the strategies and precautions necessary for conducting successful and safe XPS experiments on these elements. Core-level photoemission can be a powerful proven tool for investigating the electronic structure, chemical bonding behaviors, and physical properties of actinides, providing valuable insights into an incredibly complex behavior of these systems. We highlight key findings from recent studies that demonstrate the potential of core-level photoemission in uncovering the unique properties of actinides and their compounds. Finally, we identify current knowledge gaps and future research directions that could enhance our understanding of actinide chemistry and physics.

Experimental investigation of Catalan vault structures based on earthen materials

The Catalan vaulting have succeeded in reducing reliance on support centers, resulting in lowered costs and expedited construction processes. This research advances the study of Catalan vaulting by exploring innovative, environmentally friendly earth-based materials. The study conducts a comprehensive comparative analysis of load-bearing behaviors across distinct vault elements: those fabricated from terracotta, raw-earth tiles, and shot-earth. Constructed and tested at a 4-meter span, full-scale vault specimens are subjected to varying distributed load configuration, followed by rupture testing employing a linear load at a quarter of the span. Experimental evidence, corroborated by FE results, indicates that both terracotta and raw earth tile vaults offer commendable performance, yet their failure loads are surpassed by vaults constructed using shot-earth. Therefore, shot-earth emerges as a sustainable alternative for constructing vault elements. Furthermore, the study demonstrates that incorporating reinforcement within shot-earth vaults increases their strength and ductility.

Theoretical investigation of the electronic structure of the Rhodium Halides molecules RhF and RhCl with dipole moment calculation

The current study involves an ab initio exploration of the ground and low-lying excited electronic states of the rhodium halide molecules RhF and RhCl using the complete active space self-consistent field (CASSCF) with multireference configuration interaction (MRCI+Q) method including single and double excitations and with Davidson corrections. We investigated the potential energy curves, the transition and permanent electric dipole moments, the electronic energy relative to the ground state Te, the harmonic frequency ωe, the internuclear distance Re, and the rotational constant Be corresponding to each of the bounded states. Our findings demonstrate good agreement with the available experimental data. Notably, this work represents the inaugural theoretical investigation of the excited states of RhF and RhCl molecules, identifying the ground state of both to be X3Π, as observed in the sole two experimental investigations.

Rationalizing the stability and noncovalent interactions of N-(benzo[d][1,3]dioxol-5-ylmethyl)-2-(methylthio)thiazole-4-carboxamide: Insights from X‐ray structure and QTAIM analysis

A novel thiazole derivative, N-(benzo[d][1,3]dioxol-5-ylmethyl)-2-(methylthio)thiazole-4-carboxamide was synthesized and the structural interpretations were accomplished unambiguously by single crystal X-ray diffraction study. Structure investigation revealed that the crystal packing is stabilized by CH…N, and NH…O intermolecular interactions. Hirshfeld surface analysis used to explore the quantitative details of noncovalent interactions which are responsible for the crystal packing. The 3D energy framework, interaction energies and lattice energy of the compound were computed. Density functional theory (DFT) calculation was also employed to study various physicochemical properties of the compound. Quantum theory of atoms in molecules (QTAIM) analysis have been performed to study the intra and intermolecular interactions present in the thiazole derivative and also validate with the experimental results.

Polarized Raman, infrared and dielectric spectra of lead-free K0.5Na0.5NbO3 piezoelectric system: insights from ab-initio theoretical and experimental studies

The K0.5Na0.5NbO3 (KNN) system has emerged as one of the most promising lead-free piezoelectric over the years. In this work, we perform a comprehensive investigation of electronic structure, lattice dynamics and dielectric properties of room temperature phase of KNN by combining ab-initio DFT based theoretical analysis and experimental characterization. We assign the symmetry labels to KNN vibrational modes and obtain ab-initio polarized Raman spectra, Infrared reflectivity, Born-effective charge tensors, oscillator strengths etc. The KNN ceramic samples are prepared using conventional solid-state method and Raman and UV–Vis diffuse reflectance spectra are obtained. The computed Raman spectrum is found to agree well with the experimental spectrum. In particular, the results suggest that the mode in range ∼840–870 cm−1 reported in the experimental studies is longitudinal optical with A1 symmetry. The Raman mode intensities are calculated for different light polarization set-ups that suggests the observation of different symmetry modes in different polarization set-ups. The electronic structure of KNN is investigated and optical absorption spectrum is obtained. Further, the performances of DFT semi-local, meta-GGA and hybrid exchange-correlations functionals, in the estimation of KNN band gaps are investigated. The KNN bandgap computed using GGA-1/2 and HSE06 hybrid functional schemes are found to be in excellent agreement with the experimental value. The COHP, electron localization function and Bader charge analysis is also performed to deduce the nature of chemical bonding in the KNN. Overall, our study provides several bench-mark important results on KNN that have not been reported so far.

Evaluation and investigation of micellar structure of pluronic copolymer nanoaggregates of Docetaxel

The study was undertaken to develop and characterize docetaxel-loaded lyophilized block co-polymeric micelles for cancer therapy treatment. The study demonstrates that micellar size, shape, zeta potential, and other characteristics of lyophilized polymeric micelles are appropriate; furthermore, because of the polymer's encapsulation and capacity to maintain the drug release, significantly reduces toxicity and adverse effects. Block co-polymeric micelles offer improved solubility and a high capacity for drug loading, perhaps enhancing the bioavailability. As per this research, the idea of employing block co-polymeric micelles to enhance the solubility of hydrophobic medications holds excellent promise as an intravenous drug delivery system. While the outcomes are encouraging, the docetaxel-loaded block co-polymeric micelles must be further evaluated for In-Vivo studies to check the targeted drug delivery.Bottom of Form

Lipid composition affects the thermal stability of cytochrome P450 3A4 in nanodiscs

Nanodiscs (NDs), self-assembled lipid bilayers encircled by membrane scaffold proteins (MSPs), offer a versatile platform for the reconstitution of membrane proteins for structural and biochemical investigations. Saturated, isoprenoid lipids are commonly found in thermophiles and have been associated with thermotolerance. To test whether these lipids confer additional stability on ND-incorporated membrane proteins, this study focuses on the thermal stability of human cytochrome P450 3A4 (CYP3A4) inside NDs composed of different phosphocholine lipids: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC). NDs were characterized using size-exclusion chromatography coupled with multi-angle light scattering (SEC-MALS) and densitometric SDS-PAGE. CYP3A4-DPhPC-NDs were found to comprise three MSP copies instead of the canonical dimer, as reported before for the empty NDs. Rapid, thermally induced unfolding of CYP3A4 inside NDs measured using circular dichroism and differential scanning fluorimetry (nanoDSF) revealed that the CYP3A4 melting temperature was dependent on ND composition. In POPC and DMPC-CYP3A4-NDs the melting temperature was comparable to CYP3A4 without NDs (59 °C). CYP3A4 in DPhPC-NDs showed an increase in melting temperature of 4 °C. Decline in CYP3A4 integrity as well as ND aggregation and disintegration occur at similar rates for all membrane types when subjected to exposure at 37 °C for several hours. The POPC and DMPC- CYP3A4-NDs show significant lipid loss over time, which is not observed for DPhPC-NDs. The results demonstrate that thermally induced denaturation of protein-NDs is a complex, multifaceted process, which is not represented well by rapid thermal unfolding experiments.

Physical, optical, thermal, structural and mechanical properties of alkaline earth borate glasses

Binary alkaline earth borate glasses were synthesized via the melt quenching technique. The density and molar volume of the resultant glasses were determined experimentally. The glass optical basicity has been found to increase with the glass polarizability. The optical properties of the glasses were comprehensively analyzed, revealing a shift in the cutoff wavelength towards longer wavelengths with increasing glass optical basicity. Additionally, the optical band gap (Eg) was estimated. Structural investigations unveiled an increase in the abundance of BO4 units as the glass optical basicity increased. Furthermore, the glass transition temperature was observed to decrease with decreasing cation field strength. Glass packing density and B2O3 packing factor were calculated to assess structural variations. The longitudinal and shear velocities were determined using the pulse echo technique, providing insights into the elastic moduli of the glasses. The Makishima and Mackenzie approach was employed to predict the elastic moduli, yielding results in good agreement with experimental data. This comprehensive analysis sheds light on the relationship between composition, structure, and mechanical properties of binary alkaline earth borate glasses, offering valuable insights for potential applications.

Investigation of the molecular structure of CHBP, biological activities and SARS-CoV-2 protein binding interaction by molecular and biomolecular spectroscopy approaches

The objective of this investigation is to learn more about the structural, electrical, spectroscopic, and physiochemical characteristics of biologically active cyano-4′-hydroxybiphenyl (CHBP). The title molecule’s optimized conformational analysis was computed using the DFT/B3LYP/6–311++G (d, p) level of theory. The observed wavenumbers were compared with theoretical FT-IR and FT-Raman spectra. 1H and 13C NMR experimental spectra in CDCl3 solution (solvent phase) were recorded and the chemical shift was calculated. NBO analysis was used to examine the transfer of charge as well as the intermolecular and intramolecular bonding of orbitals. The TD-DFT (time-dependent DFT) approach was used to estimate theoretical values for both the gas and solvent (ethanol) in the corresponding transitional research, which was conducted using UV–Vis’s spectra. Energy gap (Eg = 0.26764 eV) implies that the strong potential for charge transfer, and the stability of the CHBP compound. CHBP compound’s has bioactive nature, its drug-likeness and biological properties were evaluated. The predicted topological polar surface area of 44.02 \\AA2 for the molecule falls within the permissible range of < 140 \\AA2. Based on the docking results, the most stable docking score value is −6.84 kcal/mol. In that interaction, MET 165 affects both phenyl rings in a pi-sulphur fashion and a single bond hydrogen with protein moieties GLN 192. This suggests that the pi-alkyl in PRO 168 is a hydroxyl substitutional ring. Our findings demonstrate the CHBP compound is a good inhibitor against the SAR COVID-19 viral protein.

Synthesis of 2-aminothiazole sulfonamides as potent biological agents: Synthesis, structural investigations and docking studies

A simplified synthetic approach involving sulfonylation followed by amino group alkylation produced new 2-aminothiazole derivatives. UV/Vis, infrared, and NMR spectroscopies confirmed their structures. Compounds 36, 22, 34, and 35 showed strong inhibition against Jack bean and Bacillus Pasteurii urease, with IC50 values from 14.06 to 20.21 μM/mL. Compounds 20, 26, 21, 29, 30, 31, and 32 exhibited potent inhibitory effects against α-glucosidase and α-amylase, with IC50 values between 20.34 and 37.20 μM/mL. Compounds 33, 26, and 27 demonstrated potent DPPH scavenging, with IC50 values around 34.4–39.2 μM/mL. FMO analysis showed compounds 21, 22, 24, and 25 having parallel aromatic ring systems due to π cloud interactions, while compounds 32 and 38 had distinct electronic density distributions. Compound 22 had HOMO and LUMO energy gaps of 5.805 eV, with bromo and fluoro substitutions in compounds 21 and 24 slightly increasing the gaps to 6.089 eV and 6.078 eV, respectively. Nitro groups in compounds 25 and 32 reduced the gaps to 0.384 eV and 1.187 eV. All compounds demonstrated high gastrointestinal absorption, non-permeability to the blood-brain barrier, and optimal skin permeation (Log Kp between −5.83 and −6.54 cm/s). Compounds 22, 24, and 38 had promising QED scores of 0.719, 0.707, and 0.860, respectively, with synthetic accessibility scores from 2.057 to 2.517. ADMET predictions indicated minimal toxicity, cardiovascular safety, and significant inhibitory potential for CYP enzymes. Strong in silico binding affinities (binding energies −5.75 to −7.63 kcal/mol) and metabolic stability suggest these derivatives are promising candidates for further drug development.

Unraveling the Geometry-Driven C═C Epoxidation and C-H Hydroxylation Reactivity of Tetra-Coordinated Nonheme Iron(IV)-Oxo Complexes.

The electronic structure and reactivity of tetra-coordinated nonheme iron(IV)-oxo complexes have remained unexplored for years. The recent synthesis of a closed-shell iron(IV)-oxo complex [(quinisox)FeIV(O)]+ (1) has set up a platform to understand how such complexes compare with the celebrated open-shell iron-oxo chemistry. Herein, using density functional theory and ab initio calculations, we present an in-depth electronic structure investigation of the C═C epoxidation [oxygen atom transfer (OAT)] and C-H hydroxylation [hydrogen atom transfer (HAT)] reactivity of 1. Using a solvent-coordinated geometry of 1 (1') and other potential tetra-coordinated iron(IV)-oxo complexes bearing rigid ligands (2 and 3), we established the geometric origin of spin-state energetics and reactivity of 1. Complex 1 featuring a strong Fe-O bond exhibits OAT and HAT reactivity in its quintet state. The lowest quintet OAT pathway has a lower barrier by ∼4 kcal/mol than the quintet HAT pathway, corroborating the experimentally observed gas-phase OAT reactivity preference. A conventional HAT reactivity preference for 2 and a comparable OAT and HAT reactivity for 3 are observed. This further supports the geometry-driven reactivity preference for 1. Noncovalent interaction analyses reveal a pronounced π-π interaction between the substrate and ligand in the OAT transition state, rationalizing the origin of the observed reactivity preference for 1.

Bioinformatics comparison of hemolysin in different bacteria and experimental evaluation of anti-cancer properties of extracts of some hemolysin-producing bacteria

Cancer is one of the main causes of death in the world. Resistance to anticancer treatments in patients with advanced solid tumors leads to new treatments. Therefore, more alternative anticancer methods have been found over time with greater specificity against tumor cells and with less or no adverse effects on normal cells. Bacterial spores of obligate anaerobes exclusively germinate in the hypoxic/necrotic areas and not in the well oxygenated areas of the body. This unique phenomenon has been exploited in using bacterial spores as a remedy for cancer. Bacterial toxins also play a significant role in either directly killing tumor cells or altering the cellular processes of the tumor cells which ultimately leads to the inhibition and regression of the solid tumor. In the microbial environment, pathogens such as Staphylococcus aureus, Bacillus cereus, or Streptococcus pyogenes produce hemolysin. This protein is used as an anti-cancer protein. To identify the production of hemolysin by bacteria, which can destroy cancer cells more effectively, different bacterial strains were first cultured in blood agar culture medium. The Strains that completely lysed red blood cells, creating transparent zones, were selected for further investigation. Then, to find out which strains have more ability to lyse red blood cells, the qualitative method of halo diameter measurement was used. Also, using quantitative methods, hemolysin strength in microtubes was determined compared to control samples. The results of the hemolysis in the microtube and the qualitative test results showed similar results. In the next step, the cell viability test was performed with the partially purified proteins. Then, bioinformatics studies such as secondary structure investigation, physicochemical properties, pseudo amino acid composition, and molecular docking were performed. The results of molecular docking showed that the hemolysin protein has the highest affinity for the cholesterol of the cytoplasmic membrane, respectively, of Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus bacteria which play a significant role in either directly killing tumor cells or altering the cellular processes of the tumor cells which ultimately leads to the inhibition and regression of the solid tumor.

Magnetic properties, structural investigation and optical studies of Er3+doping Cd-Mg spinel ferrite

Magnetic properties, structural investigation and optical studies of Er3+doping Cd-Mg spinel ferrite

Investigation of phase structure and electrical properties of PMN-PSN-PNN–PZT ceramics with different PNN content

Investigation of phase structure and electrical properties of PMN-PSN-PNN–PZT ceramics with different PNN content

Investigation of solution structures in a nonlinear electric transmission network incorporating dissipative elements through physical phenomena analysis

This paper presents an innovative approach to solving the voltage equation in a multi-coupled nonlinear transmission network with dissipative elements. By employing the G′G2 -expansion method and fractional derivatives, we explore the behavior of current and voltage, considering memory effects. Our investigation delves into the impact of fractional calculus on signal transmission, revealing insights into period, amplitude, and propagation direction. Additionally, we analyze the influence of obliqueness angles and various fractional-order derivatives on voltage waveforms Stability analysis demonstrates the significant role of dissipative elements and modulation parameters on signal stability and network resistance to interference. Furthermore, we examine the effects of free parameters on signal transmission characteristics. Our findings highlight the intricate interplay between fractional order, wave obliqueness, and physical parameters on voltage propagation, addressing gaps in previous research.

An improved artificial spin ice structure for restoring ice degeneracy

It is known that rare-earth-based pyrochlore oxide may accommodate the well-defined two-in-two-out spin ice state with its tetrahedral unit. Low-energy excitation is argued to favor the highly concerned monopole state which attracts essential attention. However, such an excitation cannot be directly tracked and imaged using advanced characterizations, raising challenges to our understanding of the physics of monopoles. In this work, we propose an improved two-dimensional artificial spin ice structure on the Shastry–Sutherland lattice to restore the degeneracy of realistic pyrochlore systems. Such a structure avoids the deficiency of inequivalent nearest and next-nearest exchanges in the planar quadrate unit, which, however, is equivalent to the tetrahedral unit of realistic pyrochlore oxides. Therefore, this spin ice model restores state degeneracy that is lost in conventional planar artificial spin ice structures, representing an improved simulator of real spin ice systems. Our careful investigations of such improved structures reveal the rich physics of spin ice excitations, including the phase diagram, which allows different ordered phases and interesting critical phase transitions between spin ice phase I and phase II. Energy spectrum analysis suggests that restoration of state degeneracy substantially reduces monopole excitation energy, resulting in a striking monopole emergency at the critical point. Furthermore, the emergent spin dimer phase in this improved model allows high-density monopole excitations and exhibits high-correlated monopole fluid states.

Investigating environmental prioritization: role of financial resources and female entrepreneurship in the Mediterranean region

PurposeIn this study, we aim to define a new ecological financial pecking order. We examine how SMEs' adherence to the environment in the Mediterranean region is impacted by their financial resources and how women Entrepreneurship could play a moderating role in this relationship.Design/methodology/approachOur data are pooled cross-sectional firm level data across 14 Mediterranean countries, with a total of 5,949 observations over the period from 2018 to 2020. We look into the moderating influence of SMEs’ female ownership on the financial sources-environmental engagement link using GLS estimations. To reach our aim we focus on seven funding sources and develop a green engagement construct using JCA. Besides, we distinguish between the least and most environmentally engaged companies in the EU and its neighborhood and compare the different interactions and possible moderations.FindingsResults show that government subsidies foster environmental engagement, followed by supplier credits with a less significant positive impact. The bank credits have the least significant beneficial influence, while non-bank financial institutions have a non-significant effect. We underline that environmental engagements are hindered by the other funds, issued bonds and internal funds.Research limitations/implicationsSMEs in the Mediterranean region, particularly the less environmentally conscious, require strong legal frameworks to enforce environmental responsibility and raise awareness. Integrating less environmentally committed EU SMEs into state subsidy strategies is a chance to improve environmental responsibility in the region.Originality/valueTo our knowledge, there are no prior studies that present a detailed financial structure and environmental management investigation for SMEs within the Mediterranean region while considering the moderating effect of women's entrepreneurship.

Structural and Electrochemical Investigation of Anode‐Supported Proton‐Conducting Solid Oxide Fuel Cell Fabricated by the Freeze Casting Process

ABSTRACTHierarchically oriented macroporous NiO–BaZr0.1Ce0.7Y0.2O3−δ (BZCY7) anode‐supporting layer (ASL) was developed using the freeze casting technique. The resulting freeze‐cast structure was analyzed through scanning electron microscopy and X‐ray computed tomography. A thin layer of BZCY7 was utilized as a proton‐conducting electrolyte, whereas La1.9Sr0.1Ni0.7Cu0.3O3−δ –gadolinium‐doped ceria 10% Gd (LSNC–GDC10) was employed and evaluated as cathode layer. The performance of the cell was assessed by means of electrochemical impedance spectroscopy and I–V–P curves at various temperatures. Furthermore, as a point of comparison, a cell with an ASL was prepared using the dry pressing method, incorporating 20 wt.% graphite as a pore‐forming agent. The freeze‐cast anode‐supported cell demonstrated a polarization resistance of 1.45 Ω cm2 at 550°C and 0.29 Ω cm2 at 750°C. Maximum achieved power densities were 0.189 and 0.429 W cm−2 at 550 and 750°C, respectively. For the cell fabricated by the dry pressing method, the maximum power densities were 0.158 and 0.397 W cm−2 at 550 and 750°C, respectively. Additionally, the tortuosity factor of the anode layer and the gas diffusion streamline in the direction of solidification were determined by using 3D X‐ray tomography imaging and subsequent image processing.

Development of Lead‐Free Defect Brownmillerite Perovskite Ceramic LiBiFeMnO5 Solid Solution for Electronic Devices

This article reports the fabrication (synthesis) and characterizations (structural, microstructural topographic surface, dielectric, transport, impedance, current–voltage, and resistive properties) of a complex lead‐free defect perovskite material of composition LiBiFeMnO5. A preliminary structural investigation of the X‐ray diffraction pattern using N‐TREOR09 methods shows monoclinic symmetry. The scanning electron microscopic spectrum examines the sample's microstructural topographic surface, fractal study, and roughness (using the standard ISO25178). The analysis of Maxwell–Wagner dielectric dispersion, relaxation, and transport mechanisms is investigated utilizing dielectric, impedance, and conductivity spectrum accumulated within the experimental frequency of (1 kHz–1 MHz) at different temperatures (30–500 °C). A nonoverlapping small polaron tunneling conduction mechanism and correlated barrier hopping mechanism in the material have helped to understand its conduction phenomena. The Ohmic and space–charge limited conduction mechanisms are investigated by the slope of the logarithmic electric field (E) and current density (J). The thermistor constant (β) is determined to be 1982.87. The temperature coefficient of resistance is found to be −0.00419, which may be suitable for negative temperature coefficient thermistors, sensors, and other related devices.

Changes of wood surfaces treated with natural-based products – Structural and properties investigation

Changes of wood surfaces treated with natural-based products – Structural and properties investigation