Structural Characterization Research Articles

Preparation, Structural Characterization, and In Vitro Modulation of the Gut Microbiota Activity of a Novel α-Glucan in Hericium erinaceus.

Hericium erinaceus (H. erinaceus) is a kind of medicinal and edible fungus that contains polysaccharide as the most studied effective component at present. In this paper, a novel α-glucan was successfully isolated from H. erinaceus fruiting bodies by hot water extraction combined with the fractional ethanol precipitation method. To analyze the monosaccharide composition, methylation and nuclear magnetic resonance spectroscopy were performed, and the polysaccharide was identified having α-(1→4)-glycosidic bonds with a single unit α-D-Glcp branch attached at the O-6 position (Mw, 1.43 × 107 g/mol, branching ratio of 9:1). Furthermore, the aqueous solution analysis demonstrated that this α-glucan adopts a rigid spherical conformation. The polysaccharide exhibited resistance to simulated gastrointestinal digestion but was effectively degraded by gut microbiota (GM), leading to significant changes in total polysaccharide content, reducing sugar, and pH value. Notably, the α-glucan was beneficial to increase the contents of acetic and propionic acids in metabolites, stimulated the growth of beneficial bacteria (Lactobacillus and Bifidobacterium), and inhibited the proliferation of harmful bacteria (Fusobacterium). Overall, the study deepened the regulatory effects of α-glucan with different ratios of main and branch chains from H. erinaceus fruiting bodies on GM, which provides theoretical support for developing of GM-targeted foods.

Emissive Traps Lead to Asymmetric Photoluminescence Line Shape in Spheroidal CsPbBr3 Quantum Dots.

The morphology of quantum dots plays an important role in governing their photophysics. Here, we explore the photoluminescence of spheroidal CsPbBr3 quantum dots synthesized via the room-temperature trioctylphosphine oxide/PbBr2 method. Despite photoluminescence quantum yields nearing 100%, these spheroidal quantum dots exhibit an elongated red photoluminescence tail not observed in typical cubic quantum dots synthesized via hot injection. We explore the origins of this elongated red tail through structural and optical characterization including small-angle X-ray scattering, transmission electron microscopy and time-resolved, steady-state, and single quantum dot photoluminescence. From these measurements we conclude that the red tail originates from emissive traps. We show that treating spheroidal quantum dots with phenethylammonium bromide decreases the line shape asymmetry and increases passivation-consistent with emissive traps due to polar facets.

Asymmetric Co-Ru Heterostructure Catalyst for Surface-Plasmon-Enhanced Photothermocatalytic CO Hydrogenation to Fuels.

Photothermal Fischer-Tropsch synthesis (FTS) aims to convert carbon monoxide (CO) into value-added long-chain hydrocarbons (C5+) under milder conditions, but the efficient C-C coupling of C1 intermediates remains challenging. Herein, a carbon-supported plasmonic CoRu5@C catalyst has been successfully constructed for promoting C-C coupling. Experimental results demonstrate that under ambient pressure and photothermal conditions at 250 °C, CoRu5@C exhibits a C5+ selectivity of 98.9% and FTS activity of 321.4 mmol gcat-1 h-1. Structural characterizations and finite element method simulations indicate that Ru-induced lattice strain in the Co-Ru heterogeneous catalyst boosts energetic charge carrier migration, promoting CO adsorption and activation. A series of in situ experiments reveal that electron-rich Co sites in the Co-Ru heterogeneous catalyst diminish C1 intermediate repulsion, boosting C-C coupling efficiency in the FTS process. This research not only provides an innovative approach to overcoming the challenges in CO hydrogenation selectivity and the synthesis of high-value fuels but also offers significant contributions to the development of sustainable energy technologies.

Mechanism Study of Cu(II)/Cd(II)/Ni(II) Ions Adsorption by Montmorillonite-Based Geopolymers: Molecular Dynamics Simulation and Structural Characterization

Mechanism Study of Cu(II)/Cd(II)/Ni(II) Ions Adsorption by Montmorillonite-Based Geopolymers: Molecular Dynamics Simulation and Structural Characterization

Self-Organization of Carbohydrate-Derived Amphiphilic Compounds: Insights into Their Supramolecular Assembly.

We describe the synthesis and self-assembly properties of two sugar-derived surfactants constructed by click reaction from readily accessible building blocks. After structural characterization, their self-assembly processes were studied in two biocompatible solvents, isopropyl myristate (IPM) and methyl laurate (ML), as well as in toluene. Detailed experiments by Dynamic Light Scattering (DLS) and Small-Angle X-ray Scattering (SAXS) confirmed the formation of reverse micelles (RMs). Our findings reveal the formation of spherical aggregates with low polydispersity indices, indicating a high degree of size uniformity. SAXS analysis further demonstrated that these aggregates possess a smooth and well-defined RMs-nonpolar solvent interface. Notably, the system in toluene as the non-polar phase exhibited a unique behavior, suggesting distinct structural characteristics that differ from those observed in the biocompatible solvents. A low-resolution structural model revealed that the aggregates contain an internal gap compatible with a reverse vesicle consisting of a bilayer of amphiphile with the hydrophilic heads pointing towards the interior and the exterior of the bilayer with toluene on both sides of the bilayer. In summary, this study explores the self-assembly characteristics of sugar-based surfactants in non-polar environments that mimic biological membranes. Our findings highlight the significant potential of these surfactants in supramolecular chemistry and glycobiology.

Synthesis, Characterization and Cytotoxicity of Photochromic Molybdenum Oxide-Doped Tungsten Oxide Polymeric Nanohybrid Films for Biomedical Applications.

Despite the known nontoxicity, stability and efficiency of WO3and MoO3 against microbes as a result of their catalytic activities, these oxides are not effective photocatalysts because the O2 absorbed cannot be reduced by the photogenerated electrons in their conduction band, which leads to the rebinding of electrons and holes on the surface. The doping of these two n-type semiconductor metal oxides and incorporation of a biocompatible, biodegradable and bioavailable polymer (such as chitosan) to form a film will, to a large extent, affect the surface area interaction and multipurpose applicability of the film as a therapeutic, controlled delivery and dual sensitive material. The WO3-NP, WO3MoO3 nanocomposites were synthesized via a deep eutectic solvent-assisted hydrothermal-based method, which afforded fine-sized nanoparticles and nanocomposites, which were further incorporated into a chitosan matrix to form nanohybrid films via the solvent casting method. The structural, optical and morphological characterization of the materials was carried out via XRD, FT-IR, UV, XPS, SEM, TEM, EDX and DLS. XRD and FT-IR analyses revealed that WO3MoO3 nanocomposites were successfully formed and incorporated into the chitosan matrix. The nanohybrid film showed antimicrobial activity with a minimum inhibitory concentration of 100 µg/mL. Furthermore, the nanohybrid film showed no significant toxicity.

Structural characterization of a polysaccharide from Qi-Gui herb pair and its anti-tumor activity in colon cancer cells

Astragalus membranaceus (Fisch.) Bunge and Angelica sinensis (Oliv.) Diels forms a classic herb pair (Qi-Gui her pair) in Chinese medicine, which was commonly used for treating menstrual anemia and microvascular ischemic diseases. While polysaccharides are known to be key bioactive components of the Qi-Gui herb pair, their structural characteristics and pharmacological activities remain underexplored. In this research, a homogeneous polysaccharide with a molecular weight of 18.1 kDa was isolated, and its structure was analyzed via high pressure size exclusion chromatography, high performance liquid chromatography, gas chromatography mass spectrometry, and nuclear magnetic resonance spectroscopy. The structural analysis revealed that AAPS-1a was composed of α-T-Glcp (5.9%), β-1,3-Galp (3.9%), α-1,4-Manp (3.6%), α-1,4-Galp (2.1%), α-1,4-Glcp (2.8%), and α-1,6-Glcp (81.7%). Furthermore, NMR analysis revealed that AAPS-1a consists of a repeat unit: α-T-Glcp-(1→4)-α-Galp-(1→4)-α-Manp-(1→4)-α-Glcp-(1→[6)-α-Glcp-(1]n→3)-β-Galp-(1→. In vitro studies showed that AAPS-1a could significantly inhibit the proliferation of HCT116 cells, and induces G1 arrest and G2/M arrest, as well as apoptosis of HCT116 cells. This study presents the inaugural report establishing a connection between the structural characteristics of Qi-Gui herbal polysaccharides and their anti-colon cancer activity, demonstrating that AAPS-1a holds promise as a therapeutic agent for the treatment of colon cancer.

Selective Carbon Enrichment from Micro/Nano Silicon–Carbon Ores via Sodium Hexametaphosphate: Mechanistic Insights and Structural Characterization

Selective Carbon Enrichment from Micro/Nano Silicon–Carbon Ores via Sodium Hexametaphosphate: Mechanistic Insights and Structural Characterization

Hydrothermal synthesis of SnO2/cellulose nanocomposites: optical, Structural, and morphological characterization

This study details the hydrothermal synthesis and characterization of SnO2/nanocellulose (NC) nanocomposites, highlighting their potential for advanced applications. X-ray diffraction (XRD) analysis confirmed the amorphous nature of the composites, with a broad peak at 25.6° and a rightward shift indicating strong SnO2-NC interactions. A sharp peak at 32.26° in the SnO2-20 sample signified a rutile structure with single-plane crystallinity. UV-Vis absorption spectra showed a significant blue shift, with bandgap values reaching 5.86 eV for SnO2-5, compared to 3.6 eV for pure SnO2, demonstrating enhanced optical properties. Photoluminescence (PL) spectra revealed prominent emissions at 384 nm and 486 nm, attributed to oxygen vacancies and defect states, which enhance luminescence and support optoelectronic applications. FTIR spectroscopy identified a peak at 3430 cm−1, confirming abundant hydroxyl groups on cellulose surfaces and high sample purity. Scanning electron microscopy (SEM) images showed uniformly distributed SnO2 nanoparticles on an amorphous NC matrix, with rod-like features contributing to irregular morphologies that impact defect density and optical behavior. These structural and optical improvements enhance charge transport and reduce carrier recombination, establishing SnO2-NC nanocomposites as promising materials for optoelectronic devices, gas sensors, and photocatalysis. The integration of eco-friendly nanocellulose offers a sustainable pathway for developing next-generation technologies with superior performance.

Comprehensive biochemical, molecular and structural characterization of subtilisin with fibrinolytic potential in bioprocessing

Enzyme deployment is proliferating extensively in industries owing to their environmentally friendly and easily degradable attributes. This article undertakes an exhaustive examination of wild subtilisin enzyme, covering purification, biochemical delineation, analytical techniques, and practical implementations. The purification methodology involved partial refinement, anionic exchange, and gel filtration chromatography, culminating in a purification factor of 3.406, corroborated by SDS-PAGE showcasing a molecular weight of ~ 42 kDa. Biochemical scrutiny unveiled the enzyme's response, with an optimal pH at 9 and temperature peak at 60 ℃. Various surfactants, metal ions, organic solvents and inhibitors exhibited notable efficacy. Substrate specificity and kinetics showcased the utmost specificity with N-Suc-F-A-A-F-pNA, registering Km and Vmax values of 0.731 ± 0.5 mM and 0.87 ± 9 × 103 U/mg, respectively. Different bioanalytical techniquesproffered insights into structural and biophysical facets. Practical applications encompassed goat skin depilation, feather disintegration, blood clot dissolution, exemplifying the enzyme's multifaceted utility. To embark upon the elucidation of structure–function relationships, a three-dimensional model was devised through homology modelling, leveraging existing subtilisin structures (PDB: 3WHI). Molecular docking score of − 8.8 kcal/mol and dynamic simulations augmented the comprehension of molecular interactions with N-Suc-F-A-A-F-pNA. This research significantly contributes to unravelling the biochemical intricacies of wild subtilisin and underscores potential industrial and biomedical prowess. Subtilisin can be explored for its thrombolytic potential in several cardiovascular diseases. It may aid in the management of thrombosis by dissolving blood clots in conditions like deep pulmonary embolism, myocardial infarction, ischemic strokes, and in atherosclerosis by breaking down fibrin in arterial plaques, thus preventing heart attacks and strokes.Graphical

Dual-Functional Silicon-Based Nanofluorescent Platform for Iron Detection and Capecitabine Delivery in Colorectal Cancer Treatment.

Colorectal cancer (CRC) poses significant challenges due to its high incidence and mortality. Addressing limitations like poor bioavailability and off-target effects of traditional chemotherapy, we engineered PDMS-CP1@1@Capecitabine nanoparticles. This novel formulation incorporates a gadolinium-based coordination polymer synthesized via a hydrothermal reaction with a thiourea Schiff-base ligand and embedded in a polydimethylsiloxane (PDMS) matrix, enhanced by the bioactive compound 1 from actinomycetes. Structural characterization demonstrated a crystalline nature with distinct XRD peaks at 21.4° and 25.6°, alongside remarkable fluorescence with peak emission at 444nm and superior Fe3+ selectivity, showing 90% quenching efficiency against Fe3+ compared to other ions. These nanoparticles reduced CRC cell viability by up to 55% at 20µg/mL, modulating USP22 and HSP90 expression, validated by molecular docking confirming hydrogen bonding interactions. PDMS-CP1@1@Capecitabine emerges as a potent targeted therapy for CRC, enhancing drug delivery and offering a novel approach for iron monitoring, pivotal for personalized treatment strategies.

Exploring the potential of Fucoidan from Laminaria japonica: A comprehensive review of its biological activities and benefits for human.

Exploring the potential of Fucoidan from Laminaria japonica: A comprehensive review of its biological activities and benefits for human.

Journey of the 2D Intrinsic Antiferromagnetic Topological Insulators in the (MnBi2Te4)(Bi2Te3)n Homologous Series.

In recent years, the study of two-dimensional (2D) intrinsic antiferromagnetic (AFM) topological insulators (TIs) has attracted considerable attention due to their unique electronic and magnetic properties, which are promising for the advancement of quantum computing and spintronic applications. MnBi2Te4, recognized as the first intrinsic AFM TI, provides a unique platform for examining theoretical predictions in the field of quantum materials. This discovery has sparked extensive research and led to numerous new insights that have improved the understanding of the interplay between magnetism and topology in two-dimensional systems. The homologous series (MnBi2Te4)(Bi2Te3)n, with its alternating layers of MnBi2Te4 and Bi2Te3, exhibits tunable magnetic and topological properties, making it a subject of intense investigation. This review comprehensively examines advances in the (MnBi2Te4)(Bi2Te3)n homologous series, including their synthesis, structural characterization, and study of magnetic and electronic properties. Key experimental observations are highlighted, which have been instrumental in elucidating the fundamental physics of these materials. Additionally, several unresolved questions and potential future research directions are discussed, providing valuable insights for researchers seeking to advance this integrated field. This review serves as a reference for understanding the potential and future advancements of 2D AFM TIs, fostering further exploration of their complex and promising properties.

Structural characterization and combined immunomodulatory activity of fermented Chinese yam polysaccharides with probiotics.

Structural characterization and combined immunomodulatory activity of fermented Chinese yam polysaccharides with probiotics.

Sustainable Valorization of Jackfruit Peel Waste: Bio‐Functional and Structural Characterization

Sustainable Valorization of Jackfruit Peel Waste: Bio‐Functional and Structural Characterization

X-ray Spectroscopy Characterization of Electronic Structure and Metal-Metal Bonding in Dicobalt Complexes.

Developing multimetallic complexes with tunable metal-metal interactions has long been a target of synthetic inorganic chemistry efforts due to the unique properties that such compounds can exhibit. However, understanding relationships between metal-metal bonding and chemical properties is challenging due to system-dependent factors that influence metal-metal and metal-ligand interactions, including ligand identity, coordination geometry, and metal-metal distance. In this work, we apply X-ray absorption and emission spectroscopy and quantum chemical calculations to describe electronic structure and bonding in a series of dicobalt complexes. The compounds with silane ligands and pseudo-octahedral coordination geometry exhibit Co-Co σ and multicentered bonding character, which we characterize from both the occupied and vacant perspectives via their contributions to the Co X-ray emission and absorption spectra, respectively. In contrast, the dicobalt complexes with a pseudotetrahedral coordination environment do not exhibit Co-Co bonding due to symmetry constraints on orbital overlap. We extend these insights to the theoretical evaluation of related dicobalt complexes to explain how ligand coordination and symmetry dictate the presence or absence of a Co-Co bond. This work highlights how fundamental insights into electronic structure and bonding through X-ray spectroscopy uncover important factors governing metal-metal interactions and guide the rational design of multimetallic complexes with tunable metal-metal bonds.

Synthesis and characterization of the crystal structure of innovative Zr2SnC (C= GNS) graphene nanosheet MAX phase

ABSTRACT A unique Zr2SnC (C= GNS) ceramic MAX phase-supported graphene nanosheet was prepared by utilising a cost-effective pressureless sintering process at a low temperature. This MAX phase was investigated at temperatures of 1000°C, 1150°C, and 1300°C. The pressureless sintering process successfully synthesised the Zr2SnC (C= GNS) MAX phase under 1300°C with a low impurity percentage (secondary phases) of Zr5Sn3C, Zr5Sn4, Zr5Sn3, and ZrC components. The highest percentage of the synthesised Zr2SnC (C= GNS) MAX phase was 61.2 Wt% at a temperature of 1300°C. Furthermore, the SBET of the prepared Zr2SnC (C= GNS) MAX phase was raised to 18.24 % when utilising the graphene nanosheet; while the porosity was highly decreased to 14.21% from its original value. Also, the I-V curves for Zr2SnC and Zr2SnC (C= GNS) are tested. The Zr2SnC (C= GNS) MAX phase has an excellent and uniform relation of the I-V curve obtaining a linear relationship between voltage and current compared with the Zr2SnC MAX phase. The findings presented here could promote the fabrication of the MAX phase Zr2SnC (C= GNS) for electronic applications utilising the pressureless sintering process to obtain a one-layer graphene nanosheet.

Full Brillouin zone, multi-band reconstruction of the electronic structure from high-harmonic spectra

While the all-optical characterization of electronic band structure has been touted as an exciting application of the solid-state high harmonic generation, the practical realization of the idea proves difficult, and neither the full potential nor the limitation of the approach are properly understood. This work demonstrates that a few suitably chosen high-harmonic spectra excited by a single quasi-monochromatic mid-infrared pulse provide sufficient information for a three-dimensional reconstruction of multiple electronic bands extending over the entire Brillouin zone. As a by-product of the surrogate-Hamiltonian approach introduced in this work, individual band-structure components such as transition dipole moments and Berry curvatures can also be obtained.

Pt(OH)x Coordination Engineering of Bifunctional Pt/NiFe LDH-O Catalyst for Robust Water Splitting.

Modulating the coordination environment of metal active sites and adjacent atoms significantly enhances the catalytic activity of heterogeneous catalysts owing to the local synergistic effect between metal sites and supports. While layered double hydroxide (LDH)-supported Pt catalysts exhibit complementary advantages and exceptional performance in overall water splitting (OWS), the absence of a robust coordination structure between Pt and LDH constrains their activity and stability. Herein, we report a coordination engineering strategy to alter the coordination structure of Pt on the surface of NiFe LDH using atomic layer deposition (ALD) for OWS. The synthesized Pt/NiFe LDH-O catalyst, featuring the 2-coordinate Pt-OH and 6-coordinate Pt-Pt, exhibits a η10 = 14 mV for hydrogen evolution reaction (HER), a η100 = 287 mV for oxygen evolution reaction (OER), and an effective OWS activity (η10 = 1.496 V) for over 200 h. Combining structural and electrochemical characterizations, we confirmed that the coordination engineering affected the nucleation and growth of Pt on NiFe LDH, leading to a decrease of Pt-OH coordination and an increase of Pt-Pt coordination, thereby enhancing the hydrolysis capability of Pt and shifting the rate-determining step (RDS) from the Volmer step to the Heyrovsky step, which contributed to the excellent OWS performance. The density functional theory (DFT) results demonstrated that the electronic structure of NiFe LDH is considerably regulated by an increase in Pt-Pt coordination, facilitating charge redistribution. Our investigation provides deep insights into the coordination regulating the electrocatalytic activity of LDH-supported metal catalysts.

Wafer-scale AA-stacked hexagonal boron nitride grown on a GaN substrate.

The stacking sequence of two-dimensional hexagonal boron nitride (hBN) is a critical factor that determines its polytypes and its distinct physical properties. Although most hBN layers adopt the thermodynamically stable AA' stacking sequence, achieving alternative stacking configurations has remained a long-standing challenge. Here we demonstrate the scalable synthesis of hBN featuring unprecedented AA stacking, where atomic monolayers align along the c axis without any translation or rotation. This previously considered thermodynamically unfavourable hBN polytype is achieved through epitaxial growth on a two-inch single-crystalline gallium nitride wafer, using a metal-organic chemical vapour deposition technique. Comprehensive structural and optical characterizations, complemented by theoretical modelling, evidence the formation of AA-stacked multilayer hBN and reveal that hBN nucleation on the vicinal gallium nitride surface drives the unidirectional alignment of layers. Here electron doping plays a central role in stabilizing the AA stacking configuration. Our findings provide further insights into the scalable synthesis of engineered hBN polytypes, characterized by unique properties such as large optical nonlinearity.