Spectral Characterization Research Articles

The identification of psychedelic compounds within Australian Acacia species

ABSTRACT N,N-dimethyltryptamine (DMT) is a psychedelic substance produced within various Acacia species; however, the range of species that contain it and the quantity of the compound found within each species is relatively unknown. This work focused on the identification of DMT in 104 plant samples, representing 79 Acacia species, utilizing a reverse phase liquid chromatographic separation prior to mass spectral characterization with a robust Q-TOF-MS method. The findings of this work determined 51 DMT-containing species, 41 of which were previously unknown to contain the psychedelic.

Integrated multispectral remote sensing approach for high-resolution spectral characterization and automated mapping of carbonate lithofacies

Field-based high-resolution carbonate facies mapping is often challenging due to the limited accessible exposure, high-degree of heterogeneity, and lack of distinct natural characteristics between different lithofacies. To mitigate this issue, we proposed a novel approach by integrating multispectral remote sensing, advanced image processing techniques, and supervised classification to perform high-resolution carbonate lithofacies mapping and utilized the extensive Mesozoic carbonate in Saudi Arabia as an example. For this study, the Tuwaiq Mountain Formation (TMF) was selected not only because of its wide aerial distribution but also its importance as conventional and unconventional hydrocarbon reservoirs in the subsurface. Our proposed method was able to map and delineate different members (T1, T2, T3) and key lithofacies in the TMF. In addition, based on the spectral characteristics, the middle member of TMF (T2) can be further subdivided into two subunits (T2-a of higher reflectance & T2-b of lower reflectance). These findings are further corroborated by detailed microfacies analysis, which validates the presence of two sub-members of T2 (T2-a: Spiculitic foraminiferal wackestone and T2-b: Coralline floatstone facies). This resulted in a revised and accurate lithofacies map that made significant modifications over older maps. The overall accuracy of TMF lithofacies is 93.4 % with a kappa coefficient of 0.88. This study demonstrates that multispectral remote sensing approach are effective at distinguishing different carbonate units and providing high-resolution carbonate facies maps. The proposed approach should be applicable to other carbonate outcrops globally and could help in improving carbonate lithofacies mapping where the outcrops are not accessible.

Mechanochemical Solid-State Immobilization of Photofunctional Dyes on Amorphous Silica Particles and Investigation of Their Interactive Mechanisms.

Amorphous silica particles (ASPs) have been reported to exhibit bioactive properties and are becoming the focus of attention as bioceramics. However, their interactions with proteins in living organisms remain to be understood and need to be investigated in order to achieve wider applications. Our research group found that chlorine (Cl)-containing ASPs are useful for protein immobilization. Photofunctional dyes (fluorescein (FS-), methylene blue (MB+)) that have the carboxy and amino groups as the main functional groups were immobilized on the Cl-containing ASPs via the mechanochemical method as the model molecule and their spectral properties were used to investigate and discuss the organic/inorganic interfacial bonding states. In FS-, the oxygen atoms of the carboxy groups in the molecule were immobilized by the hydrogen bonds with the silanol groups on the ASPs surfaces, indicating that there is an optimum Cl content for the immobilization as the monomer state. In the case of MB+, as the Cl concentration in the ASPs increases, the immobilization via the electrostatic interactions between the Cl in the ASPs and the terminal dimethylamino group, and the hydrogen bonding between the N atoms of the MB+ hetero ring and the particle silanol group were enhanced. These results mainly suggest that the protein adsorption system occurs through the hydrogen bonding between the carboxy groups of the protein and the silanol groups on the particles and via electrostatic interactions between the amino groups of the protein and the dissociated silanol groups and the contained Cl at the particles. Thus, the spectral characterization using dyes as probes is expected to predict the protein interactions with the amorphous silica particles.

Spectral characterization of elemental emissions, experimental insights and theoretical evaluation

This experimental study delves into the spectral analysis of five discrete spectral lamps, namely helium, sodium, mercury, cadmium and zinc, utilizing a suite of scientific instrumentation including an optical spectrometer with converging lenses and a diffraction grating. The primary objective is to determine the wavelengths corresponding to visible spectral lines emitted by these lamps. Calibration of the spectrometer with the helium lamp facilitated the derivation of the diffraction grating constant. Subsequent measurements of diffraction angles allowed for the computation of experimental wavelengths, which were then compared with theoretical values. Analysis revealed slight discrepancies between experimental and theoretical values, likely attributed to systematic errors such as extraneous light sources and parallax errors in angle measurements. Furthermore, examination of spectral line splitting demonstrated the removal of degeneracy within specified energy levels, resulting in the observation of distinct spectral components. Overall, this study underscores the significance of meticulous experimental techniques in the elucidation of fundamental physical phenomena and highlights the interplay between theory and observation in spectral analysis.

Nickel(II) and Palladium(II) complexes with imine-based tridentate ligand: Synthesis, spectral characterization, Antimicrobial, cytotoxicity and DFT studies

The organic compound (Z)-2-bromo-2-(5-bromo-2-hydroxy-3-methoxybenzylidene)-N-metylhydrazine-1-carbothioamide (L1H2) and its nickel(II) complex [Ni(L1)(PPh3)](1) and palladium(II) complex [Pd(L1)(PPh3)](2) were synthesized and characterized using various spectroscopic methods, including NMR,FT-IR, HRMS, and UV–Vis spectroscopy. Single-crystal X-ray diffraction analysis was used to determine the crystal structures of [Ni(L1)(PPh3)](1) and [Pd(L1) (PPh3)](2). The Hirshfeld surface analysis was used to study various interactions in the crystal structure of complexes. In addition, an energy framework computational analysis was also done to gain a further understanding of the structural details of the complexes. DFT-based calculations were done for the ligand and its associated metal complexes to establish the correlations between their structural characteristics and integral properties. Ligand and its complexes were evaluated for their antimicrobial effects. The antimicrobial effects of ligands and their complexes were assessed. It was found that both Ni(II) and Pd(II) complexes showed better antimicrobial activity.The minimum inhibitory concentration for the [Ni(L1)(PPh3)] complex ranges from 1.95–250 µM; for the [Pd(L1)(PPh3)] complex, it ranges from 3.5–250 µM; and for the ligand, it ranges from 62.5–250 µM against both bacterial and fungal strains. The synthesized compounds were tested for anti-proliferative assays against the HELA carcinoma cell line. The IC50 values obtained were 98.83 µM for the ligand, 83.09 µM for the Ni(II) complex, and 86.74 µM for the Pd(II) complex, suggesting Ni(II) complex a stronger anti-cancerous agent compared to the Pd(II) complex.Noteworthy, both complexes and standard drugs (ciprofloxacin and nystatin) showed non-cytotoxic behavior towards the normal HEK-293 cell line. The increased efficacy and selective cytotoxicity of the complexes highlight their potential as a candidate for further investigation and development into a potent therapeutic agent as an antimicrobial and anticancer agent.

Crystal structure, spectral characterization, in vitro, molecular docking and DFT studies of pyranopyrazole derivatives

Two Pyranopyrazole derivatives, namely, methyl-11-(2-chlorophenyl)-16-methyl-8-[(4-methylbenzene)sulfonyl], -14-phenyl-12-oxa-8,14,15-triazatetracyclo[8.7.0.02,7.013,17] heptadeca-2(7), 3, 5, 13(17), 15-pentaene-10-carboxylate, C38H37N3S1O5 and butyl‑16-methyl-8-[(4-methylbenzene)sulfonyl]-11,14-diphenyl-12-oxa-8,14,15-triazatetracyclo[8.7.0.02,7.013,17] heptadeca-2(7),3,5, 13(17), 15-pentaene-10-carboxylate, C35 H30 Cl N3 O5 S with phenyl and chlorophenyl substitutions were synthesized successfully, and crystallized by the slow evaporation technique. The pyranopyrazole derivatives were characterized by spectroscopic techniques including UV–visible, FTIR, and mass spectroscopy, and their 3D-structural arrangements were also confirmed by single crystal XRD studies. Both compounds crystallize in the triclinic crystal system with the centrosymmetric space group P-1, which is identified by the X-ray single-crystal structure. These compounds were examined for in vitro and molecular docking studies with the enzymes 1hny, 1pgg, and 4 cox and thus correspond to diabetes and inflammation. The observed results showed better binding energy and inhibition constants for inflammation involving enzymes. The chemical reactivity and electronic arrangement of the compounds have been revealed by DFT studies.

Spectral characterization of a blue light-emitting micro-LED platform on skin-associated microbial chromophores

The therapeutic application of blue light (380 – 500nm) has garnered considerable attention in recent years as it offers a non-invasive approach for the management of prevalent skin conditions including acne vulgaris and atopic dermatitis. These conditions are often characterised by an imbalance in the microbial communities that colonise our skin, termed the skin microbiome. In conditions including acne vulgaris, blue light is thought to address this imbalance through the selective photoexcitation of microbial species expressing wavelength-specific chromophores, differentially affecting skin commensals and thus altering the relative species composition. However, the abundance and diversity of these chromophores across the skin microbiota remains poorly understood. Similarly, devices utilised for studies are often bulky and poorly characterised which if translated to therapy could result in reduced patient compliance. Here, we present a clinically viable micro-LED illumination platform with peak emission 450 nm (17 nm FWHM) and adjustable irradiance output to a maximum 0.55 ± 0.01 W/cm2, dependent upon the concentration of titanium dioxide nanoparticles applied to an accompanying flexible light extraction substrate. Utilising spectrometry approaches, we characterised the abundance of prospective blue light chromophores across skin commensal bacteria isolated from healthy volunteers. Of the strains surveyed 62.5% exhibited absorption peaks within the blue light spectrum, evidencing expression of carotenoid pigments (18.8%, 420–483 nm; Micrococcus luteus, Kocuria spp.), porphyrins (12.5%, 402–413 nm; Cutibacterium spp.) and potential flavins (31.2%, 420–425 nm; Staphylococcus and Dermacoccus spp.). We also present evidence of the capacity of these species to diminish irradiance output when combined with the micro-LED platform and in turn how exposure to low-dose blue light causes shifts in observed absorbance spectra peaks. Collectively these findings highlight a crucial deficit in understanding how microbial chromophores might shape response to blue light and in turn evidence of a micro-LED illumination platform with potential for clinical applications.

Bio‐evaluation of pyrazolone‐furan derived Schiff base Cr(III), Co(II), Ni(II), Cu(II), and Zn(II) nano‐sized complexes: Design, spectral characterization, antimicrobial efficacy, antioxidant activity, apoptotic activity, and cell cycle analysis

A tridentate pyrazolone‐furan Schiff's base ligand, [(E)‐4‐(((5‐[2‐fluorophenyl]furan‐2‐yl)methylene)amino)‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐3H‐pyrazol‐3‐one] (PFSB), was produced by condensation between compounds 5‐(2‐fluorophenyl)furan‐2‐carbaldehyde and 4‐amino‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐3H‐pyrazol‐3‐one. Spectroscopic characterization evidence suggested the tridentate nature (ONO) of pyrazolone‐furan Schiff's base ligand (PFSB) and coordinated to the metal (II/III) moieties through nitrogen and oxygen donor sites giving tetra‐ and/or hexa‐coordinated geometry to complexes. The complexes have been supported by elemental analyses, molar conductance, magnetic moments, spectral analyses, EPR, ligand field parameters, XRD, and thermogravimetric measurements. Theoretical optimization employing the density functional theory (DFT) was accomplished on the molecular structures of the compounds in question, and subsequently, the quantum chemical descriptors were computed. Cr(III), Co(II), Ni(II), and Zn(II) complexes were allocated octahedral coordination, while the Cu(II) complex was allocated square‐planar coordination. The SEM, TEM, XRD, AFM, and EDX of the studied complexes unveiled distinct and strong diffraction peaks, signifying their crystalline nature, and providing evidence of their particle sizes being within the nano‐size. The crystal sizes calculated for all complexes were determined to be ranging from 27.73 to 76.39 nm. However, the Cr(III) complex exhibited a particle size exceeding 100 nm. The interactions between metal complexes and calf thymus DNA, and their potential for mimicking insulin activity, were investigated in a controlled lab setting by measuring their ability to inhibit alpha‐amylase. The anti‐microbial potential of the ligand (PFSB) and complexes (C1‐C5) were tested. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT‐DNA) interaction with the nano‐sized metal (II/III) chelates. Our flow cytometry data indicate significant levels of apoptosis and cell cycle arresting in both liver and breast cancer cell lines.

New 2H‐Chromene‐Based Hydrazone Derivatives as Promising Anti‐Breast Cancer Agents: Efficient Synthesis, Spectral Characterization, Molecular Docking, and ADMET Studies

AbstractA new series of 2H‐chromene‐based hydrazones (10 a–w, 12 a–d, and 14 a–d) were efficiently synthesized by the reaction of substituted 2H‐chromene aldehydes (8 a–w) with various hydrazines (9, 11, and 13) in absolute ethanol under microwave irradiation as well as by lemon juice mediated conventional heating. The structures of synthesized target molecules were identified by spectroscopic analysis methods (1H NMR, 13C NMR, FT‐IR, and HRMS). The in vitro anticancer activity of the new 2H‐chromene‐based hydrazones were evaluated on the three breast cancer cell lines (MCF‐7, MDA MB‐231, and MDA MB‐468) by MTT assay. Among these synthesized compounds, 10 r and 12 b exhibited the most potent antiproliferative activities with IC50 values at 9.12±0.45 μM and 10.71±0.67 μM respectively, against MCF‐7 cell. Flowcytometric analysis revealed that these two potent compounds, 10 r and 12 b arrested the cell cycle at the G2/M phase and induced apoptosis of proteins in a dose‐dependent manner. It was further confirmed by Hoechst staining and Annexin V‐FITC assay. Additionally, compounds 10 r and 12 b were examined by in silico molecular docking, which revealed that compound 10 r displayed excellent binding affinity energy of around −10 kcal/mol with human HER2 receptor. Also, the ADME studies validated the hybrid compounds showing promising physicochemical, pharmacokinetic, and drug‐like attributes. Broadly, these results underscored the potential of 2H‐chromene‐based hydrazone derivatives as promising anticancer agents.

Synthesis, Spectral Characterization, and Structural Modelling of Di- and Trinuclear Iron(III) Monensinates with Different Bridging Patterns

In the present study, we report the solid-state isolation and structural characterization of novel iron(III) complexes of the veterinary antibiotic monensin. Monensic acid (MonH × H2O) forms a dinuclear complex of composition with FeCl3 [FeCl(Mon)2]2 (1), while its interaction with FeSO4 leads to the isolation of a triangular oxo-ferric coordination species [Fe3O(Mon × H2O)6(H2O)2(OH)] (2). During the procedure resulting in 2, oxidation of the Fe(II) ions by atmospheric oxygen was observed. In the presence of organic bases, both complexation reactions proceeded to successfully deprotonate the carboxylic function of the ligand. Iron(III) complexes 1 and 2 were characterized by IR, EPR, NMR, and Mössbauer spectroscopies as well as with thermal (TG-DTA/MS) and elemental analyses. In addition, the structures of the two coordination compounds were modelled and selected calculated parameters were compared with the experimental results. The biological assay revealed the enhanced antibacterial potential of the newly obtained complexes against the Gram-positive aerobic microorganisms Bacillus cereus and Bacillus subtilis.

Integrating p-type phenazine into covalent triazine framework to achieve co-storage of cations and anions for quasi-solid-state dual-ion batteries

Covalent triazine frameworks (CTFs) with bipolar features have garnered significant attentions in energy storage systems. Further, the integration of p-type active sites into CTFs is highly desirable. Herein, we integrated p-type phenazine into CTFs (PZ-CTF) to generate dual active centers with ion co-storage mechanism. Interestingly, the application of PZ-CTF as the cathode material in various battery systems was demonstrated. In lithium-based dual-ion batteries (LDIBs) with liquid electrolyte, PZ-CTF can show high discharge specific capacity (190.8 mAh g−1 at 200 mA g−1) and excellent rate capability (92.8 mAh g−1 at 3000 mA g−1). In quasi-solid-state LDIBs, PZ-CTF can possess high discharge specific capacity (187.5 mAh g−1 at 200 mA g−1) and long-cycle stability (at 500 mA g−1 over 1000 cycles). In addition, in graphite-based DIBs (GDIBs), PZ-CTF also shows considerable electrochemical properties. Moreover, the continuous co-storage mechanism of PF6− and Li+ in PZ-CTF was confirmed by the theoretical calculations and spectral characterizations. This work opens a new avenue for integrating multi-polar organic electrode materials with multiple reaction mechanisms for the application of various battery systems.

Spectral Characterization of Silver Nanoparticles Biosynthesized from Lysinibacillus fusiformis and its Antibacterial Efficacy Against Multidrug-Resistant Bacteria Isolated from Chronic Wounds

Spectral Characterization of Silver Nanoparticles Biosynthesized from Lysinibacillus fusiformis and its Antibacterial Efficacy Against Multidrug-Resistant Bacteria Isolated from Chronic Wounds

Massively Reconstructing Hydrogen Bonding Network and Coordination Structure Enabled by a Natural Multifunctional Co-Solvent for Practical Aqueous Zn-Ion Batteries.

The practical application of aqueous Zn-ion batteries (AZIBs) is hindered by the crazy Zn dendrites growth and the H2O-induced side reactions, which rapidly consume the Zn anode and H2O molecules, especially under the lean electrolyte and Zn anode. Herein, a natural disaccharide, d-trehalose (DT), is exploited as a novel multifunctional co-solvent to address the above issues. Molecular dynamics simulations and spectral characterizations demonstrate that DT with abundant polar -OH groups can form strong interactions with Zn2+ ions and H2O molecules, and thus massively reconstruct the coordination structure of Zn2+ ions and the hydrogen bonding network of the electrolyte. Especially, the strong H-bonds between DT and H2O molecules can not only effectively suppress the H2O activity but also prevent the rearrangement of H2O molecules at low temperature. Consequently, the AZIBs using DT30 electrolyte can show high cycling stability even under lean electrolyte (E/C ratio = 2.95 µL mAh-1), low N/P ratio (3.4), and low temperature (-12°C). As a proof-of-concept, a Zn||LiFePO4 pack with LiFePO4 loading as high as 506.49 mg can be achieved. Therefore, DT as an eco-friendly multifunctional co-solvent provides a sustainable and effective strategy for the practical application of AZIBs.

Spectral characterization of the impact of modifiers and different prepare temperatures on snow lotus medicinal residue-biochar and dissolved organic matter

This study involved the production of 20 biochar samples derived from secondary medicinal residues of Snow Lotus Oral Liquid, processed within the temperature range of 200–600 °C. Additionally, four medicinal residues, including dissolved organic matter (DOM), from 24 samples obtained using the shaking method, served as the primary source material. The investigation focused on two key factors: the modifier and preparation temperature. These factors were examined to elucidate the spectral characteristics and chemical properties of the pharmaceutical residues, biochar, and DOM. To analyze the alterations in the spectral attributes of biochar and medicinal residues, we employed near-infrared spectroscopy (NIR) in conjunction with Fourier-infrared one-dimensional and two-dimensional correlation spectroscopy. These findings revealed that modifiers enhanced the aromaticity of biochar, and the influence of preparation temperature on biochar was diminished. This observation indicates the stability of the aromatic functional group structure. Comparative analysis indicated that Na2CO3 had a more pronounced structural effect on biochar, which is consistent with its adsorption properties. Furthermore, we utilized the fluorescence indices from UV–visible spectroscopy and excitation-emission-matrix spectra with the PARAFAC model to elucidate the characteristics of the fluorescence components in the DOM released from the samples. The results demonstrated that the DOM released from biochar primarily originated externally. Aromaticity reduction and increased decay will enhance the ability of the biochar to bind pollutants. Those results confirmed the link between the substantial increase in the adsorption performance of the high-temperature modified charcoal in the previous study and the structural changes in the biochar. We investigated the structural changes of biochar and derivative DOM in the presence of two perturbing factors, modifier and preparation temperature. Suitable modifiers were selected. Preparation for the study of adsorption properties of snow lotus medicinal residues.

Moisture‐Resistant Orange Emitters with Near‐Unity Quantum Yield from Mn2+ Alloyed Vacancy‐Ordered Quadruple Perovskites

AbstractMn2+‐doped metal halide perovskites present remarkable optical properties in optoelectronic applications, although the realization of high efficiency and stability is still a challenge. In this work, a series of highly efficient and stable orange‐emitting Mn2+ alloyed Cs4Cd1‐xMnxBi2Cl12 single crystals are successfully synthesized via a hydrothermal reaction. Combined with the crystal structure and spectral characterization at 7 K, the site occupation of Mn2+ and defect emission are systematically discussed. Benefiting from the effective [BiCl6]3−→[MnCl6]4− energy transfer and lattice distortion, these single crystals exhibit a maximum internal and external quantum yield of ≈97% and ≈65% at 35% heavy doping level. Interestingly, these Mn2+‐alloyed single crystals exhibit remarkably waterproof stability, no decrease in emission intensity is observed after immersion in deionized water for 4 h. After soaking in deionized water for 100 days, the internal quantum yield can still maintain 44%, implying good chemical stability and moisture resistance due to the formation of protective BiOCl layer. This work provides new insights into the optimization mechanism for Mn2+ luminescence and overcoming the downside of their waterproofing in humid conditions.

Haemers’ Conjecture: An Algorithmic Perspective

Characterizing graphs by their spectra is a fundamental and challenging problem in spectral graph theory, which has received considerable attention in recent years. A major unsolved conjecture in this area is Haemers’ conjecture which states that almost all graphs are determined by their spectra. Despite many efforts, little is known about this conjecture so far. In this paper, we shall consider Haemers’ conjecture from an algorithmic perspective. Based on some recent developments in the generalized spectral characterizations of graphs, we propose an algorithm to find all possible generalized cospectral mates for a given n-vertex graph G, assuming that G is controllable or almost controllable. The experimental results indicate that the proposed algorithm runs surprisingly fast for most graphs with several dozen vertices. Moreover, we observe in the experiment that most graphs are determined by their generalized spectra, e.g., at least 9945 graphs are determined by their generalized spectra among all randomly generated 10,000 graphs on 50 vertices in one experiment. These experimental results give strong evidence for Haemers’ conjecture.

Production and characterization of polyvinyl alcohol films containing essential oil

Packaging plays an important role in protecting foodstuffs against physicochemical damage and microbial activity, as well as extending shelf life. In recent years, petrochemical compounds that cause environmental pollution and contamination due to their non-biodegradability have been replaced by biocompatible polymer-based films in the food packaging industry. Due to aromatic essential oils (EO), various biological activities, and their potential to replace chemical preservatives in the field of food preservation, Star Anise essential oil, which has properties, such as free radical scavenger, antibacterial, antifungal and antiviral, was used as an additive in this study. Biodegradable and biocompatible polyvinyl alcohol (PVA) polymer was used as the matrix and polymer-based films were produced in 3 different concentrations. Spectral analysis, structural, chemical, and thermal characterizations, and surface morphologies of the produced films by the direct incorporation method were examined. In addition, the antibacterial activities of the films on Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 25922, and Acinetobacter baumannii ATCC BAA 747 bacteria were investigated. As a result of the examinations, it was determined that an interfacial interaction occurred between the matrix and the filler, and the produced films were thermally resistant and showed antibacterial activity against Gram (+)/Gram (−) bacteria. Consequently, it can be concluded that PVA films containing Star Anise essential oil present a prospective substitute in a variety of industrial packaging systems, including those for food, medicine, and cosmetics.

Bioconversion of Eel Skin Waste into Valuable Collagen: Isolation, Spectral Characterization, and Biocompatibility Assessment

Bioconversion of Eel Skin Waste into Valuable Collagen: Isolation, Spectral Characterization, and Biocompatibility Assessment

Mechanical and Thermal Properties of Aged Helmet Outer Shells Made of Acrylonitrile-Butadiene-Styrene

Acrylonitrile-butadiene-styrene (ABS) material is widely used as a protective rigid shell and impact absorber in bike helmets, providing vital protection against head injuries under specific working conditions. However, ABS aging in helmets could affect the safety factor of helmets and shorten the service life. Exploring the transformation during aging process for real assembled helmets made of ABS out shells is crucial for the investigation and fabrication of high performance helmets. Herein, the effect of long-term aging on the physical properties of practical helmets made of ABS outer shells has been discussed systematically. Four different types of helmets were subjected to different aging conditions, i.e., outdoor environment, ultraviolet exposure, hot air, and humid-heat conditions. The impact property and stiffness tests were carried out as a function of aging time and aging conditions. The measured helmets were capable of meeting engineering tolerances when aged under outdoor, ultraviolet, and hot air conditions, and could deliver competitive mechanical performance to their pristine helmets. Yet, after aging under humid-heat for 800 h, the helmets showed an obvious decrease in impact strength, gloss, and stiffness. The influence of different aging conditions was further investigated by thermal and spectral characterizations. The study might provide some valuable advice for helmet performance evaluation.

Design of quetiapine fumarate loaded polyethylene glycol decorated graphene oxide nanosheets: Invitro-exvivo characterization

Quetiapine Fumarate (QF) is an atypical antipsychotic with poor oral bioavailability (9%) due to its low permeability and pH-dependent solubility. Therefore, this study aims to design QF-loaded polyethylene glycol (PEG) functionalized graphene oxide nanosheets (GON) for nasal delivery of QF. In brief, GO was synthesized using a modified Hummers process, followed by ultra-sonication to produce GON. Subsequently, PEG-functionalized GON was prepared using carbodiimide chemistry (PEG-GON). QF was then decorated onto the cage of PEG-GON using the π-π stacking phenomenon (QF@PEG-GON). The QF@PEG-GON nanocomposite underwent several spectral characterizations, in vitro drug release, mucoadhesion study, ex vivo diffusion study, etc. The surface morphology of QF@PEG-GON nanocomposite validates the cracked nature of the nanocomposite, whereas the diffractograms and thermogram of nanocomposite confirm the conversion of QF into an amorphous form with uniform distribution in PEG-GON. Moreover, an ex vivo study of PEG-GON demonstrates superior mucoadhesion capacity due to its surface functional groups and hydrophilicity. The percent drug loading content and percent entrapment efficiency of the nanocomposite were found to be 9.2±0.62% and 92.3±1.02%, respectively. The developed nanocomposite exhibited 43.82±1.65% drug release within 24h, with the Korsemeyer-Peppas model providing the best-fit release kinetics (R2: 0.8614). Here, the interlayer spacing of PEG-GON prevented prompt diffusion of the buffer, leading to a delayed release pattern. In conclusion, the anticipated QF@PEG-GON nanocomposite shows promise as a nanocarrier platform for nasal delivery of QF.