Spectroscopy Analysis Research Articles

Enhancing enset fiber‐reinforced polylactic acid composites through different surface treatments for emerging applications

AbstractEnvironmental concerns and the over‐exploitation of natural resources have driven the search for eco‐friendly materials. Agro/industrial waste, often discarded, can be repurposed as fillers in biocomposites. However, bio‐fibers present challenges such as poor compatibility, high moisture absorption, and variable mechanical properties. This study examines various fiber surface modification techniques, including NaOH, silane, alkali‐silane, and pectinase enzyme treatments on enset fiber (EF) to produce sustainable reinforced poly(lactic acid) (PLA) composites. Untreated EF/PLA composites were fabricated for comparison. Results showed that the applied EF surface treatments, especially using pectinase enzyme, significantly enhanced mechanical, thermal, and thermomechanical properties. Pectinase‐treated EF/PLA composites displayed increased tensile strength by 55.99%, elongation at the break by 39.49%, tensile modulus by 32.59%, impact strength by 51.50%, flexural strength by 51.85%, flexural modulus by 60.90%, and improved thermal stability as compared to untreated composite. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses verified better fiber‐matrix interaction with clarity due to reduced non‐cellulosic components. Pectinase enzyme treatment emerged as the most effective, eco‐friendly method, enhancing the enset fiber's potential in polymer biocomposites, suitable for automotive interiors and packaging industries, reducing synthetic plastic pollution, and utilizing agricultural waste.Highlights Enset fibers were modified by NaOH, silane, NaOH/silane, and pectinase enzyme The modified enset/PLA composites were prepared by compression molding Surface treatments enhanced the enset‐PLA matrix interaction Pectinase‐modified enset/PLA composite showed superior properties Improved properties of enset composites make it ideal for various applications

Visualizing supramolecular assembly behavior, stimulus response, and solid state emission of higher-order Pt2+ aggregates.

Here, we present the first instance of a highly efficient red tetramer aggregate with tunable emission based on a cationic platinum(II) complex in conjunction with a silver cluster anion counterpart. This system exhibits multicolor emission response behaviors, which can be conveniently and directly detected through spectroscopic analysis, showcasing intriguing luminescence changes. The self-assembly of Pt⋯, π-π, and hydrogen bonding interactions not only enables an intriguing color adjustment from green to yellow emission, and eventually to red emission, but also demonstrates the co-existence of the monomer, excimer, and aggregation. These phenomena are further accompanied by well-defined nanostructures. The self-assembly process of these structures exhibits an isodesmic growth mechanism, which is dependent on temperature. In this regard, it exhibits potential applicability in multi-mode logic gates that rely on external stimuli such as concentration, solvent, and temperature. The sensitivity of the aggregates towards chemical stimuli combined with their exceptionally bright emission characteristics renders them suitable for diverse applications including solid-state lighting sensing mechanisms and anticounterfeiting measures. The multi-stimuli responsive phosphorescence and self-assembly behaviors of the cationic platinum(II) complex were substantiated by X-ray crystal structure determination, 1H NMR analysis spectroscopic investigations, computational calculations and scanning electron microscopy (SEM) studies.

High-temperature carbon dioxide capture in a porous material with terminal zinc hydride sites.

Carbon capture can mitigate point-source carbon dioxide (CO2) emissions, but hurdles remain that impede the widespread adoption of amine-based technologies. Capturing CO2 at temperatures closer to those of many industrial exhaust streams (>200°C) is of interest, although metal oxide absorbents that operate at these temperatures typically exhibit sluggish CO2 absorption kinetics and instability to cycling. Here, we report a porous metal-organic framework featuring terminal zinc hydride sites that reversibly bind CO2 at temperatures above 200°C-conditions that are unprecedented for intrinsically porous materials. Gas adsorption, structural, spectroscopic, and computational analyses elucidate the rapid, reversible nature of this transformation. Extended cycling and breakthrough analyses reveal that the material is capable of deep carbon capture at low CO2 concentrations and high temperatures relevant to postcombustion capture.

Design, Synthesis, ssDNA Binding Affinities, and Evaluation of Novel Metal‐Centered Ferrocene as an Effective Antimicrobial and DNA Cleavage Agent

ABSTRACTMetal (Co3+, Ni2+, and Pt2+)–centered and noncentered ferrocene–Schiff bases were prepared. They have been structurally characterized by spectroscopic methods, elemental analysis, conductivity, and magnetic moment. Electron spin resonance was used for the characterization of the Co3+‐centered complex. All synthesized compounds showed antibacterial activity against all tested Gram‐positive and Gram‐negative strains, as well as potent antifungal effect against Candida species. Remarkably, these compounds demonstrated greater efficacy against Gram‐positive bacteria than Gram‐negative. Without an additional oxidant or reductant, the compounds exhibited DNA cleavage capability in the dark. The development of synthesized novel chemical compounds having DNA cleavage and antimicrobial activity plays a profound role in the advancement of medical therapeutics.

Mycosynthesis of silver nanoparticles from endophytic Aspergillus parasiticus and their antibacterial activity against methicillin-resistant Staphylococcus aureus in vitro and in vivo

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is a drug-resistant and biofilm-forming pathogenic bacteria with severe morbidity and mortality. MRSA showed resistance against currently available antibiotics. Thus, there is an urgent need to develop novel effective treatments with minimal side effects to eliminate MRSA.AimIn this study, we aimed to mycosynthesize silver nanoparticles (AgNPs) using the endophytic fungus Aspergillus parasiticus isolated from leaves of Reseda Arabica and to examine their antibacterial activity against MRSA.ResultsScreening of fungal secondary metabolites using gas chromatography–mass spectroscopy (GC–MS) analysis revealed the presence of high content of bioactive compounds with antibacterial activities. AP-AgNPs were mycosynthesized for the first time using ethyl acetate extract of A. parasiticus and characterized by imaging (transmission electron microscopy (TEM), UV–Vis spectroscopy, zeta potential, X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), and Fourier transform infrared spectroscopy (FTIR)). The agar well diffusion method revealed the antibacterial activity of AP-AgNPs against MRSA with 25 μg/mL of minimum inhibitory concentration (MIC). AP-AgNPs were shown to exert antibacterial action via a bactericidal mechanism based on flow cytometry, scanning electron microscopy, and transmission electron microscopy assessment. Our data demonstrated the effective interaction of AP-AgNPs with the bacterial cell membrane, which resulted in cell membrane damage and disruption of cell surface structure. Furthermore, AP-AgNPs successfully prevented the development of MRSA biofilms by disturbing cell adhesion and destructing mature biofilm reaching over 80% clearance rate. Interestingly, topical application of AP-AgNPs to superficial skin infection induced by MRSA in mice effectively promoted wound healing and suppressed bacterial burden.ConclusionOur results provide a novel green nanoparticle drug design with effective therapeutic potential against MRSA-induced skin infection.

From Bulk to Surface: A Raman Spectroscopic Analysis of Solvation Structures in Concentrated Acetonitrile Electrolytes for Li–O2 Batteries

From Bulk to Surface: A Raman Spectroscopic Analysis of Solvation Structures in Concentrated Acetonitrile Electrolytes for Li–O₂ Batteries

Heterocycles and a Sorbicillinoid from the Coral-Derived Fungus Penicillium chrysogenum

A detailed chemical study of the culture of a coral-derived fungus Penicillium chrysogenum resulted in the isolation and identification of four new aromatic heterocycles chrysoquinazolinones A–B (1–2) and chrysobenzothiazoles A–B (3–4), along with a new sorbicillinoid 4-carboxylsorbicillin (5). Chrysoquinazolinones A–B (1–2) combine a quinazolinone fragment with a bicyclo[2.2.2]octane or a pyrrolidone moiety, respectively, demonstrating the unexpected structures of marine natural products. Chrysobenzothiazoles A–B (3–4) possess a benzothiazole system and are the second isolation of this class of skeleton compounds from marine organisms. The existence of the pair of enantiomers (±3) was deduced by chiral HPLC analysis. Their structures and absolute configurations were elucidated by detailed spectroscopic analysis, comparison with the literature data, single-crystal X-ray crystallographic analysis and TDDFT-ECD calculations. Compound 5 exhibited moderate cytotoxicity against K562 and NCI-H446 cell lines, with IC50 values of 15.00 μM and 16.87 μM, respectively.

Comparative assessment of enamel surface remineralisation with three different dentifrices: An energy dispersion x-ray spectroscopy analysis

Comparative assessment of remineralisation of enamel surface when treated with three different dentifrices. Sixty-six extracted upper right first premolars were demineralized to form artificial white spot lesions. The samples were divided into 3 groups: Group 1-Biomin F, Group 2- Clinpro ToothCreme, Group 3- Amflor. They were treated with three different dentifrices (22/ group) for 14 days in simulated oral conditions. Energy dispersion X-Ray Spectroscopy was done pre and post remineralistaion. The primary evaluation parameter for this study was the Ca/P ratio. As per the results, the maximum increase in Ca/P ratio was seen in Group1, followed by Group 3 and 2 respectively. The results were found to be statistically significant. (p=0.045 i.e. p<0.05) The secondary evaluation parameter for this study was the change in Fluoride content. As per the results, the maximum increase in Fluoride content was seen in Group 2 which was followed by Group 3 which is equivalent to Group 1. However, the results were found to be statistically non-significant. (p=0.219 i.e. p>0.05) Biomin F has the highest remineralisation efficiency when compared to the other 2 dentifrices. Biomin F contains an optimum combination of fluoride (600 ppm), phosphate and calcium ions, incorporated within the structure of the glass itself. The glass gradually dissolves over up to 12 hours neutralizing acids in the mouth and deposit fluorapatite. Thus, it can be used in patients undergoing orthodontic treatment to prevent or reduce the formation of white spot lesions.

Fine-Tuning Porous Structure of Zirconium-Based Metal-Organic Frameworks for Efficient Separation and Purification of Astaxanthin by Defect Engineering.

Efficient separation of bioactive compounds from nature source, particularly that of astaxanthin (AXT), remains challenging due to their low content in complicated matrix and readily degradable structure. Herein, a modulator-induced defect engineering is presented on the stable zirconium-based metal-organic frameworks (Zr-MOFs) to optimize pore size and pore chemistry for the efficient separation and purification of AXT for the first time. High adsorption capacity of 26.21mgg-1 is achieved on the best-performing defect Zr-MOF (d-UiO-67-4), superior over the other reported adsorbent for AXT. Meanwhile, d-UiO-67-4 exhibits the selective adsorption of AXT over other carotenoids analogues with similar structure and properties. This is attributed to the preferential non-covalent interactions between defect framework and AXT revealed by the spectroscopy analysis and density functional theory (DFT) calculations. High purity of AXT with 89.0%±2.3% extraction efficiency can be realized after the purification of AXT by d-UiO-67-4. The practical separation performance of d-UiO-67-4 for AXT extracted from Haematococcus pluvialis is demonstrated by fixed-bed column-based dynamic adsorption and desorption experiments. This work broadens the preparation methods for thermosensitive active substances and provided new research ideas for the controlled adsorption of functional food factors.

Optimizing Carbon Structures in Laser-Induced Graphene Electrodes Using Design of Experiments for Enhanced Electrochemical Sensing Characteristics.

In this study, we explored the morphological and electrochemical properties of carbon-based electrodes derived from laser-induced graphene (LIG) and compared them to commercially available graphene-sheet screen-printed electrodes (GS-SPEs). By optimizing the laser parameters (average laser power, speed, and focus) using a design of experiments response surface (DoE-RS) approach, binder-free LIG electrodes were achieved in a single-step process. Traditional trial-and-error methods can be time-consuming and may not capture the interactions between all variables effectively. To address this, we focused on linear resistance and substrate delamination to streamline the DoE-RS optimization process. Two LIGs, designated LIG A and LIG B, were fabricated using distinct and optimized laser settings, which resulted in a sheet resistance of 25 ± 2 Ω/sq and 21 ± 1 Ω/sq, respectively. These LIGs, characterized by scanning electron microscopy, Raman spectroscopy, and contact angle analysis, exhibited a highly porous morphology with 13% pore coverage and a contact angle <50°, which significantly increased their hydrophilicity when compared to the GS-SPE. For the electrochemical studies, the oxidation of NO2- ion by the graphene-based working electrodes was investigated, as it allowed for the direct comparison of the LIGs to the GS-SPE. These included cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulsed voltammetry studies, which revealed that LIG electrodes displayed a remarkable 500% increase in peak current during NO2- oxidation compared to the GS-SPE. The LIGs also demonstrated improved stability and sensitivity (420 ± 30 and 570 ± 10 nAμM-1 cm-2) compared to the GS-SPE (73 ± 4 nAμM-1 cm-2) in the oxidation of NO2- ions; however, LIG B was more susceptible to ionic interference than LIG A. These findings highlight the value of applying statistical approaches such as DoE-RS to systematically improve the LIG fabrication process, enabling the rapid production of optimized LIGs that outperform conventional carbon-based electrodes.

Bufadienolides from Helleborus foetidus and their cytotoxic properties on MCF-7 breast cancer cells.

Twelve bufadienolides and six 19-norbufadienolides were isolated from the aerial parts of Helleborus foetidus. They consist of aglycons and glucosides and include nine previously undescribed compounds and a compound reported for the first time as a genuine natural product. Their structures were established by extensive spectroscopic analysis and the structure and absolute configuration of two previously unreported 3,4-epoxy derivatives were confirmed by single crystal X-ray diffraction analysis. The compounds were tested for their cytotoxicity on MCF-7 human breast cancer cells. They show differential cytotoxic activity with IC50 values in the range of 2.4 nM - >10 μM. The potency of the activity strongly correlates with the presence of a C-19 aldehyde group. The data complement the scientific basis underpinning the use of H. foetidus in anthroposophic medicine for the integrative treatment of cancer.

Discovery of undescribed anthracycline-derived polyketides with cytotoxicity from endophytic Streptomyces chartreusis M7.

Endophytic actinomycetes exhibit considerable potential for the production of biologically active metabolites due to their coevolution with plant hosts. In this study, an endophytic Streptomyces chartreusis M7 was isolated from Houttuynia cordata Thunb. Bioactivity-guided investigation of the metabolites produced by this strain led to the identification of thirteen anthracycline-derived polyketides, including five unreported anthraquinones designated streptoquinones A-E (1-5) and two undescribed angular polyketides named chartins A and B (6-7) along with six knowns. Their structures were elucidated through comprehensive spectroscopic analysis and ECD calculations. Notably, chartins A (6) and B (7) feature angular tetracyclic and pentacyclic skeletons, respectively, which have undergone several oxidative rearrangements. Moreover, streptoquinone A (1) exhibited moderate cytotoxicity against A549 cells, with an IC50 value of 4.8 μM.

Radiation-induced nanogel engineering based on pectin for pH-responsive rutin delivery for cancer treatment.

This research investigates the formulation of a nanogel complex using pectin and poly(acrylic acid) (PAAc) to encapsulate rutin. The nanogel's pH-responsive behavior and its potential as a targeted drug delivery platform are investigated. The gamma irradiation-induced crosslinking mechanism is elucidated, highlighting its role in creating a stable three-dimensional network structure within the polymer matrix. Fourier transform infrared spectroscopy analysis sheds light on the molecular interactions within rutin and the nanogel-rutin complex. The pH-responsive behavior of the nanogel is explored, showcasing its ability to release rutin selectively in response to pH variations and displaying high physical and chemical stability. Transmission electron microscopy imaging provides visual insights into nanogel morphology and interactions. The cumulative drug content from the nanogel was 86.14 ± 2.61%. The pH-dependent release profile of the nanogel was examined, demonstrating selective rutin release in response to varying pH levels. Cytotoxicity studies were conducted against four human cancer cell lines-HepG2, A549, MCF-7, and HCT-116 showing significant reductions in IC50 values, indicating enhanced therapeutic efficacy. Additionally, molecular docking studies revealed strong binding interactions of rutin with VEGFR-2 and EGFRT790M. Our nanogel compound 5 significantly reduced the IC50 values for HepG2, A549, MCF-7, and HCT-116 cells by 58.19%, 81.29%, 71.81%, and 67.16%, respectively. Furthermore, it lowered the IC50 values for VEGFR-2 and EGFRT790M by 29.66% and 68.18%, respectively.

Mechanisms of Increasing Weld Depth during Temporal Power Modulation in High‐Power Laser Beam Welding

Understanding the fundamental mechanisms of action for increasing weld depth during temporal power modulation in laser beam welding could allow dissimilar rotational welding without the introduction of concomitant turbulence, but with enhanced intermixing. The investigations are conducted on 30 mm‐diameter round bars of stainless steel alloy 1.4301 and nickel base alloy 2.4856 utilizing a 16 kW disk laser beam source. Modulation frequencies are 0/50/100/200 Hz at low, medium, and high amplitudes of laser beam power. The influence on the process and weld characteristics is investigated through high‐speed imaging with grayscale analysis, keyhole depth measurements, metallographic sections, and energy‐dispersive X‐ray spectroscopy analysis. The objectives are successfully achieved, and the underlying mechanism is maintaining the keyhole depth at a higher level for modulation frequencies of 200 Hz and a high amplitude of laser beam power, which is related to the keyhole inertia. Based on this, a novel welding mode with a constant keyhole depth is proposed. Furthermore, up to 20% increase in weld depth is achieved, a saturation limit for the modulation frequency is identified, intermixing within the weld is enhanced, and a model for predicting the weld depth based solely on measurements of the surface width is developed.

Gentidelasides A-G: loganin derivatives from Gentiana delavayi with reducing Aβ secretion via suppressing BACE1 expression.

Gentidelasides A-G (1-7) seven unreported loganin derivatives and fourteen known compounds (8-21) were isolated from the flowers of Gentiana delavayi Franch. Their structures including absolute configurations were unambiguously elucidated by analysis of extensive NMR spectroscopy, ECD, and HRESIMS, as well as enzymatic hydrolysis. In vitro bioassay, compound 7 showed obvious inhibitory effects on the production of Aβ40 and Aβ42, with IC50 values of 0.052 ± 0.0023 nM and 1.52 ± 0.95 nM, respectively, which probably exert their prevention of Alzheimer's disease by inhibiting the expression of β-site amyloid precursor protein cleaving enzyme 1. The molecular docking simulation revealed that compound 7 inhibited BACE1 through hydrophilic and hydrophobic interactions in the active site cavities.

Linear Inverse Sandwich Complexes of Tetraanionic Benzene Stabilized by Covalent δ-Bonding with Late Lanthanides.

A series of dilanthanide benzene inverse sandwich complexes of the type (CpiPr5Ln)2(μ-η6:η6-C6H6) (1-Ln) (Ln = Y, Gd, Tb, Dy, Tm) are reported. These compounds are synthesized by reduction of the respective trivalent dimers CpiPr52Ln2I4 (Ln = Y, Gd, Tb, Dy, Tm) in diethyl ether with potassium graphite in the presence of benzene, and they feature an unusual linear coordination geometry with a highly planar benzene bridge as verified by single-crystal X-ray diffraction. The Ln-Bzcentroid distances of 1-Ln are the shortest distances observed to date, ranging from 1.943(1) Å for 1-Tm to 2.039(6) Å for 1-Gd. Structural, spectroscopic, and magnetic analyses together with density functional theory calculations support the presence of a rare, unsubstituted tetraanionic benzene in each compound, which is stabilized by strong covalent δ bonding interactions involving the filled π* orbitals of (C6H6)4- and vacant dxy and dx2-y2 orbitals of the Ln3+ ions. Notably, 1-Ln are the first examples of compounds of the later lanthanides to feature an unsubstituted tetraanionic benzene.

Advanced sensing and analytical techniques for quality control of tobacco flavoring

Abstract Assuring stability and uniformity in tobacco cut filler flavoring is crucial for cigarette product quality. This review focuses on advanced sensing and analytical techniques like gas chromatography-mass spectrometry and electronic nose technology. These methods analyze the chemical composition of flavoring liquids and detect volatile components in tobacco cut filler samples, thereby evaluating flavoring stability and uniformity. The review also acknowledges additional technologies like near-infrared spectroscopy and continuous flow analysis. Strengths and weaknesses of these detection techniques are discussed, providing insights into quality control of tobacco cut filler flavoring.&amp;#xD;

Modification of Poly(3-Hydroxybutyrate) with a Linear Polyurethane Modifier and Organic Nanofiller—Preparation and Structure–Property Relationship

The growing demand for products made of polymeric materials, including the commonly used polypropylene (PP), is accompanied by the problem of storing and disposing of non-biodegradable waste, increasing greenhouse gas emissions, climate change and the creation of toxic products that constitute a health hazard of all living organisms. Moreover, most of the synthetic polymers used are made from petrochemical feedstocks from non-renewable resources. The use of petrochemical raw materials also causes degradation of the natural environment. A potential solution to these problems is the use of biopolymers. Biopolymers include biodegradable or biosynthesizable polymers, i.e., obtained from renewable sources or produced synthetically but from raw materials of natural origin. One of them is the poly(3-hydroxybutyrate) (P3HB) biopolymer, whose properties are comparable to PP. Unfortunately, it is necessary to modify its properties to improve its processing and operational properties. In the work, hybrid polymer nanobiocomposites based on P3HB, with the addition of chain, uncross-linked polyurethane (PU) and layered aluminosilicate modified with organic salts (Cloisite®30B) were produced by extrusion process. The introduction of PU and Cloisite®30B to the polymer matrix (P3HB) influenced the processing parameters beneficially and resulted in a decrease in the extrusion temperature of more than 10 °C. The influence of the simultaneous addition of a constant amount of PU (10 m/m%) and the different amounts of nanoadditives (1, 2 and 3 m/m%) on the compatibility, morphology and static mechanical properties of the resulted nanobiocomposites were examined. The component interactions by Fourier transformation infrared spectroscopy (FTIR) analysis, nano- and microscale structure studies using small-angle X-ray scattering (SAXS) and morphology by scanning electron microscopy (SEM) were carried out, and the hardness and tensile strength of the obtained polymer nanobiocomposites were determined. FTIR analysis identified the compatibility of the polyester matrix, PU, and organomodified montmorillonite, the greatest being 3 m/m% Cloisite30B content. The addition of PU to the polyester elasticizes the material and decreases the material’s strength and ductility. The presence of nanoclay enhanced the mechanical properties of nanobiocomposites. The resulting nanobiocomposites can be used in the production of short-life materials applied in gardening or agriculture.

Synthesis and Structure of Ethyl 4-Aryl-2-oxo-2,3,4,10-tetrahydrobenzo[4,5]imidazo[1,2-&lt;i&gt;a&lt;/i&gt;]pyrimidine-3-carboxylates

Ethyl 4-aryl-2-oxo-2,3,4,10-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carboxylates were prepared by three-component one-pot condensation of diethylmalonate, aromatic aldehyde, 2-aminobenzimidazole in ethanol in the presence of piperidine. The structure of the obtained compounds was determined by 1H, 13С NMR spectroscopy and single crystal X-ray diffraction analysis.

Toward Commercial-Scale Perovskite Solar Cells: The Role of ALD-SnO2 Buffer Layers in Performance and Stability.

Hybrid organic-inorganic perovskite solar cells (PSCs) have shown significant potential in photovoltaic applications due to their superior optoelectronic properties. However, the conventional electron transport layer (ETL) of C60 in PSCs poses challenges such as incomplete coverage and metal diffusion, leading to reduced performance and stability. This work explores the efficacy of atomic layer deposition (ALD) of SnO2 as an interlayer between C60 and electrode to enhance the performance and stability of devices. Devices with varying SnO2 thicknesses were fabricated, revealing that a 15 nm ALD-SnO2 layer optimally improved the power conversion efficiency (PCE) to 23.85%, compared to the 22.86% achieved with a BCP layer. Moreover, the SnO2-based devices exhibited superior open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF). Modules (30 × 30 cm) with ALD-SnO2 demonstrated notable enhancements in efficiency and uniformity, suggesting the potential for scalable commercial applications. Photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analyses confirmed the improved charge extraction and reduced recombination with the SnO2 buffer layer. This research indicates that ALD-SnO2 is a promising interlayer candidate for PSCs, providing a pathway toward higher efficiency and stability in perovskite solar technology.