Characteristic Absorption Bands Research Articles

Development of essential oils inclusion complexes: a nanotechnology approach with enhanced thermal and light stability

Essential oils (EOs) are volatile compounds that may have antimicrobial and antioxidant properties. Despite their potential application, low water solubility and chemical instability are limiting factors. Nanoencapsulation processes can overcome this problem, protecting against external factors and promoting a moderate release. Therefore, the objective of the present study was to encapsulate Cymbopogon citratus (CC) and Origanum vulgare (OV) essential oils in β-cyclodextrin (βCD) complexes. Different ratios (w/w) between βCD and EOs (96:4, 92:8, 90:10, 88:12) were tested, seeking greater entrapment efficiency. The particles were characterized by yield, entrapment efficiency, size distribution, morphology, crystallinity, infrared spectroscopy, and thermal behavior. Furthermore, the thermal (70 °C) and photochemical (UV) stability of the free and encapsulated EO was evaluated for 48 h. The results showed that the βCD-CC 90:10 and βCD-OV 90:10 formulations presented greater entrapment efficiency. Crystalline structures of varying sizes (200 to 800 nm), trapezoidal shape, and tendency to aggregation were obtained. Changes in the βCD crystalline organization and the suppression of characteristic free oil absorption bands suggest the EO entrapment. Regarding stability results, βCD-CC remained constant when CC showed losses of 20% (photodegradation) and 60% (thermal degradation) after 48 h of stress exposure. Free OV showed slight variations in absorbance over time, while βCD-OV remained constant over 24 h (thermal degradation) and maintained 60% of oil over 48 h of photo exposure. Furthermore, OV and CC demonstrate color change over time, while βCD-OV and βCD-CC remained constant. The results demonstrate that nanoencapsulation can be an interesting tool for protecting EOs.

Chiral Pd2L4 Capsules from Readily Accessible Tröger's Base Ligands Inducing Circular Dichroism on Fullerenes C60 and C70.

The induction of chirality on pristine fullerenes through non-covalent embedding in an asymmetric nano-confinement has only been rarely reported. Bringing molecules with such a unique electronic structure and broad application range into a chiral environment is particularly appealing for the development of chiroptical materials, enantioselective photoredox catalysts and systems showing chirality-induced spin selectivity (CISS). In this study, we report the formation of a chiral, configurationally stable Pd2L4capsule assembled from aC2-symmetric, 'ribbon-shaped' ligand with a Tröger's base naphthalimide (TbNaps) backbone, easily synthesized in three steps from commercially available compounds. Embedding chirality directly into the ligand backbone ensures a relatively lightweight receptor design whose aromatic panels create a strongly shielded inner cavity of about 700 Å3volume. Fullerenes C60and C70, as well as a pair of corannulenes, can be bound in acetonitrile (where unsubstituted fullerenes are insoluble) and X-ray structures of host-guest complexes were obtained. Tight interactions between the chiral host and the fullerene guests leads to the induction of a circular dichroism (CD) on the characteristic absorption bands of the forbidden π-π* transitions of the fullerenes, backed up by sTDA TD-DFT calculations and detailed investigation of the electronic excited states.

Interfacing inorganic halide perovskites with metal-organic frameworks: Color tunable emission, energy transfer, and advanced anti-counterfeiting application

This work presents an inorganic halide perovskite (CsPbBr3) is interfaced with a europium metal-organic framework (Eu-MOF). The presence of characteristic absorption edge and band edge emission of CsPbBr3 reveal a successful formation of CsPbBr3@Eu-MOF hybrid. The bi-flower morphology of Eu-MOF has tetragonal structure with space group P4322. The conical part of the bi-flower consists of many squared rods of edge length 200 nm. The CsPbBr3@Eu-MOF shows color-tunable emission under different excitation wavelengths whose CIE color coordinate covers the entire green to red region. The maximum luminous efficacy of the optical radiation achieved is 359 lm/W, and the maximum color purity is 94.4 %, which is significant for optical applications. Further for anti-counterfeiting application, a pattern “LMDD” is encrypted on four different substrates and the color change is captured under different excitation wavelengths. The results show that CsPbBr3@Eu-MOF is highly suitable for encryption and decryption of security codes particularly on plastic surface.

Propeller‐Shaped Blatter‐Based Triradicals: Distortion‐Free Triangular Spin System and Spin‐State‐Dependent Photophysical Properties

Herein, we report the synthesis and properties of triptycene‐based C3v‐ and Cs‐symmetric stable radical trimers. SQUID magnetometry showed the propeller‐shaped trimers were both an antiferromagnetic equilateral triangle spin system with small spin‐spin interaction J/kB ~ −120 K and –106 K, leading to ca. 4/6 coexistence of the doublet/quartet states in thermal equilibrium at room temperature. The trimers exhibited characteristic NIR absorption bands reaching 1000 nm, which was solely ascribed to the triradical in the doublet state by variable‐temperature spectroscopic studies and quantum chemical calculations. Taking advantage of the spin‐specific absorption feature, we found that the triradicals in the low‐spin state undergo symmetry‐breaking charge transfer, while those in the high‐spin state fall into a monomer‐like excited state.

Propeller-Shaped Blatter-Based Triradicals: Distortion-Free Triangular Spin System and Spin-State-Dependent Photophysical Properties.

Herein, we report the synthesis and properties of triptycene-based C3v- and Cs-symmetric stable radical trimers. SQUID magnetometry showed the propeller-shaped trimers were both an antiferromagnetic equilateral triangle spin system with small spin-spin interaction J/kB ~ -120 K and -106 K, leading to ca. 4/6 coexistence of the doublet/quartet states in thermal equilibrium at room temperature. The trimers exhibited characteristic NIR absorption bands reaching 1000 nm, which was solely ascribed to the triradical in the doublet state by variable-temperature spectroscopic studies and quantum chemical calculations. Taking advantage of the spin-specific absorption feature, we found that the triradicals in the low-spin state undergo symmetry-breaking charge transfer, while those in the high-spin state fall into a monomer-like excited state.

Comparison of a Quantum Cascade Laser and an Interband Cascade Laser for the Detection of Stable Carbon Dioxide Isotopes Using Tunable Laser Absorption Spectroscopy.

Quantum cascade lasers (QCLs) and interband cascade lasers (ICLs) are widely used as light sources in tunable laser absorption spectroscopy because they emit in the mid-infrared region where many strong and characteristic absorption bands are present. In this paper, we compare the performance of these lasers emitting at about 2310.1 cm-1 to determine an optimal light source for detecting isotopic ratios of carbon dioxide (CO2). Our results show that the QCL has a higher relative intensity noise of up to 15 dBc/Hz compared to the ICL over the entire measured frequency range. In addition, it has a higher frequency fluctuation. However, the maximum tuning range of the QCL is up to 5.2 cm-1 compared to up to 3.8 cm-1 for the ICL. Both lasers lose more than half of their tuning range when the tuning rate is increased to 10 kHz. When measuring the isotope ratio of CO2, an uncertainty in the value of ‰ was achieved with the ICL and of ‰ with the QCL, both at an integration time of 0.2 s. In summary, the QCL is more appropriate for applications that require a larger spectral tuning range, such as the measurement of a complex gas mixture, while the ICL has an excellent signal-to-noise ratio and is therefore better suited for applications that require higher precision.

Nanotube formation and coating of hydroxyapatite-polyvinyl alcohol-collagen composite on Ti-6Al-4V metal alloy

Abstract Ti-6Al-4V metal is widely used as an implantable material due to its biocompatibility and corrosion resistance; however, it has low bioactive properties. The formation of nanotubes and a hydroxyapatite-polyvinyl alcohol-collagen composite coating on Ti-6Al-4V metal aims to enhance its biocompatibility and bioactivity. The nanotube oxide layer Ti-6Al-4V was formed by the anodization method. The composite’s infrared spectrum showed characteristic absorption bands from Hydroxyapatite (HAp), polyvinyl alcohol, and collagen. The composite-coated Ti-6Al-4V metal, both non-nanotube, and nanotube, showed a typical diffraction pattern of HAp and titanium element. The electron microscope image showed the uniform granular form of HAp. The corrosion test results showed that composite-coated nanotube Ti-6Al-4V metal could not improve corrosion resistance. It is also relevant to the in vitro test in a lactate ringer solution that showed the higher Ca2+ ion of nanotube Ti-6Al-4V metal than that of non-nanotube Ti-6Al-4V metal.

Sustainable enhancement of wool fibers using Hymenocrater platystegius flower and natural dyes for improved Insect-Repellent and color properties

This study investigates the application of Hymenocrater platystegius flower as a natural mothproofing agent for wool fibers and examines the effects of aluminum mordanting on the dyeing properties of wool treated with various natural dyes. Wool fibers were treated with Hymenocrater platystegius flower powder and aluminum salts, followed by dyeing with Madder, Reseda lutea, Indigo, or Walnut shell dyes using different mordanting methods. FTIR analysis revealed the characteristic absorption bands and confirmed the interactions between the wool fibers and the treatment agents. The insect-repellent properties were assessed by weight loss measurements after exposure to Anthrenus verbasci larvae, showing significant improvements in treated samples, particularly with the combination of Hymenocrater platystegius and aluminum mordanting. GC–MS analysis of the essential oil identified as α-Pinene, Trans-Verbenol, Linalool, and β-Bourbonene as the main constituents, contributing to the insect-repellent effect. The L*a*b* color space analysis demonstrated that aluminum mordanting significantly enhances the color strength and stability of dyed wool, with pre-mordanting generally providing better results. The study further evaluated the washing and light fastness, as well as the mothproofing properties of the dyed wool samples. These results indicate that the weight loss percentages of treated wool fiber after washing are slightly higher than before washing, but the difference is not significant. Overall, the use of aluminum mordant in conjunction with Hymenocrater platystegius flower powder not only improves the color characteristics of wool dyed with natural dyes but also provides effective mothproofing properties, making it a viable and eco-friendly option for textile applications.

Effect of TiO2 nanoparticles on the assembly of a copolymer-clay dispersion

Nanocomposites based on copolymer and clay minerals are attracting increasing attention as they are appropriate for extensive applications. In this work, we present results from an experimental study on the effects of TiO2 nanoparticles on a pluronic-F127/laponite water solution in the sol state. Differential Scanning Calorimetry (DSC), Dynamic Light Scattering (DLS) and Fourier Transform Infrared Attenuated Total Reflection Spectroscopy (FTIR-ATR) were used to characterize the systems. By DSC and DLS measurements the occurrence of micellization was first investigated. The temperature induced self-assembly was then studied by DLS identifying three relaxations associated to differently sized diffusing structures. The correlation between dynamics and bonding structure was thoroughly investigated by analyzing some specific infrared vibrational bands. In particular, the study of the characteristic absorption band of the ether groups in the dry state allowed to evaluate the amorphous/crystalline component evidencing the presence of more extended conformations in presence of the higher TiO2. Finally, the analysis of the bending mode for the residual water provided valuable insight about structural OH groups enabling a distinction between different types of water molecules associated to the copolymer/nanoparticle systems.

Temperature Effects on the Optical Properties of Bismuth Nanoparticles Prepared by PLAL for Antibacterial Activity

Bismuth nanoparticles (Bi NPs) constitute a promising technology for combating infectious illnesses and bacterial resistance to antibacterial treatments. Bi NPs were synthesized by Pulsed Laser Ablation in Liquid (PLAL) using a 532 nm second-harmonic generation Nd:YAG laser. Bi NPs samples were prepared in 10, 35, 50, 75, and 90 ˚C water for various laser energies and number of laser pulses. Ultraviolet-visible (UV-Vis) spectra measurements revealed a characteristic plasmonic absorption band indicative of metallic bismuth nanosized particles. Field emission scanning electron microscopy (FESEM) analysis showed that the water temperature during the ablation process affected the size and morphology of Bi NPs. The average Bi NP size at 60 ˚C was 28 nm, considerably smaller than the 55 nm average observed at 10 ˚C. The antimicrobial properties of Bi NPs against two opportunistic pathogens, E. coli and S. aureus, were assessed. For S. aureus, the inhibition zone of Bi NPs prepared at 60 ˚C was greater than that of samples prepared at 10 ˚C. Further, Bi NPs exhibited lower potency against E. coli than S. aureus in both samples.

Bioactive stem cell-laden 3D nanofibrous scaffolds for tissue engineering

This study presents biomimetic nanoscaffolds composed of electrospun polycaprolactone-collagen (PCL-Coll) nanofibers, loaded with bioactive Arnebia euchroma (AE) extract and stem cells, to develop cell-based tissue engineering constructs. The incorporation of AE extract, known for its antioxidant and anti-inflammatory properties, into the PCL-Coll nanofibers resulted in nanoscaffolds denoted as PCL-Coll/AE0, PCL-Coll/AE5, PCL-Coll/AE10, and PCL-Coll/AE15, corresponding to AE extract concentrations of 0.0, 5.0, 10.0, and 15.0 wt%, respectively. The PCL-Coll/AE nanoscaffolds exhibited high porosity values of 62.81 ± 4.78 %, 59.9 ± 2.10 %, 52.44 ± 2.66 %, and 46.32 ± 1.35 %, respectively, thereby providing an optimal 3D environment for cell attachment and proliferation. Analysis of the AE extract revealed the presence of abundant shikonin, a key bioactive compound, as indicated by its characteristic absorption bands at 490, 520, and 560 nm. FE-SEM data confirmed the homogeneous immobilization of AE compounds within the 3D nanofiber scaffolds, with fibers averaging 316 ± 137 nm in diameter, falling within the range of natural collagen fibers. To evaluate the structural integrity of the fully stem cell-laden scaffolds, we assessed cell growth, cell attachment within the PCL-Coll/AE nanoscaffolds, the cytoprotective effects of AE extract, and the expression levels of stemness-related genes, including Nanog, Rex1, Sox2, Oct4, Klf4, and C-Myc. Real-time PCR assays indicated that key indicators of stemness were upregulated, with average increases from 120 ± 15 % in PCL-Coll/AE0 to 250 ± 30 % in PCL-Coll/AE15 over a two-week period. These upregulations promote cell proliferation and facilitate cell cycle progression. Data indicate that increasing the concentration of bioactive AE extract within the scaffolds enhanced cell adhesion on the scaffold surface and improved cell viability after 7 days of culture, with viability rising from 109 ± 6.15 % in PCL-Coll/AE0 to 145.5 ± 10.11 % in PCL-Coll/AE15. Cytoprotective assays against oxidative stress induced by H₂O₂ revealed relative cell viability for PCL-Coll/AE0, PCL-Coll/AE5, PCL-Coll/AE10, and PCL-Coll/AE15 as 42.78 ± 5.85 %, 49.29 ± 6.79 %, 64.98 ± 3.32 %, and 78.68 ± 3.09 %, respectively. These results correlate with the antioxidant potency of AE extract compounds, particularly shikonin and its derivatives. Therefore, the cell-laden biomimetic PCL-Coll/AE15 scaffolds, which demonstrate sustained stemness features and a continuous local release of bioactive AE compounds, represent a promising candidate for tissue engineering applications.

Spray pyrolysis grown Cu and Ni co-doped ZnO thin films: a study of their structural, optical, wettability, and photocatalytic performance

This study explores the impact of Cu and Ni doping on the structural, wettability, optical, and photocatalytic properties of ZnO thin films. The co-doped thin films, with varying Ni concentrations, were deposited using a spray pyrolysis method onto pre-heated soda lime glass substrates. X-ray diffraction analysis confirmed the hexagonal wurtzite structure with preferred orientation primarily along the (002) plane, while crystallinity decreased with higher Ni concentrations. Scanning electron microscopy reveals a compact, adherent structure in all films, with Ni incorporation altering the surface morphology. Fourier transform infrared spectroscopy identified characteristic absorption bands for metal-oxygen bonds. Optical analysis indicated that all thin films exhibited over 88% average transmittance in the visible region, accompanied by a red shift in the optical bandgap. Photoluminescence spectra exhibited a broad emission band in the visible region, indicating intrinsic and extrinsic defects induced by doping. Co-doping transforms the wettability character of ZnO thin films from hydrophilic to hydrophobic. Finally, the photodegradation efficiency of the thin films against methylene blue under sunlight significantly increases from 72% to 92% with an increase in Ni concentration.

A method for the quantitative analysis of Lycium barbarum polysaccharides (LBPs) using Fourier-transform infrared spectroscopy (FTIR): From theoretical computation to experimental application

Lycium barbarum polysaccharides (LBPs) is one of the most important active substances in Lycium barbarum (LB). It is a challenge to quantitatively determine the content due to their complex structures and lack of suitable reference standard in practice. In this study, a quantitative analysis method of LBPs in LB was established based on Fourier-transform infrared spectroscopy (FTIR). The stretching vibration of CO on the pyranose ring of saccharide at 921 cm−1 was selected as the characteristic absorption band by theoretical calculation, which can’t be impacted by the preparation methods and interfered by the component monosaccharides. The molecular weight CRM of dextran (Mw 63.3 kDa) served as the reference standard. The introducing internal standard (KSCN) can obtain a good precision (RSD = 1.10 %) and effectively compensate for the analysis errors caused by the environment, quality loss and uneven distribution during the tablet pressing processes. The methodological verification suggested that the method had good accuracy according to the recovery rate (96.61 %–105.45 %) and the blank recovery (92.39 %–99.37 %), respectively. The LOD and LOQ of CRMD were 0.10 mg and 0.32 mg, respectively. The polysaccharide content of LB from 24 different regions (0.50–2.54 %) and 10 batches of LB extracts (7.09–10.56 %) determined by the developed method less than the ones using phenol–sulfuric acid assay (1.95 %–4.83 % for LB and 9.83–15.53 % for extracts, respectively). The established method based on FTIR could be served as a supplement to phenol–sulfuric acid assay and a rapid quantitative assay for polysaccharides products. In additional, this study provided a new idea for the quantitative analysis of plant polysaccharides.

Accurate determination of alcohol-based diesels using optimal chemical factors

Sustainable environmental policies and energy crises have led to a trend of blending different alcohols into diesel to partly replace the decreasing fossil fuels. To improve the rapidity and accuracy of determining alcohols exist in methanol and ethanol diesel, optimal chemical factors (OCF) feature selection schemes were presented based on different near infrared (NIR) characteristic absorption bands generated by different chemical structure information utilizing support vector machine (SVM). Through comparative analysis with SVM based on entire spectra, Monte Carlo uninformative variable elimination (MC-UVE) spectra and competitive adaptive reweighted sampling (CARS) spectra, the proposed OCF-SVM not only achieved 100 % accuracy, precision, recall and F1-score in classification, but also exhibited the best performance in prediction analysis with the smallest sum of squares due to error (SSE), root mean squared error (RMSE), mean absolute percentage error (MAPE) and the highest R-square. The overall outcomes indicate that the OCF method based on molecular chemical structures can select more pertinent and interpretable spectral features, thereby making the classification and prediction of alcohol-based diesels more exact and credible. Further, the developed OCF strategy together with SVM could supplement existing methods for analysis of alcohol-based diesels and is expected to be recommended for detecting the chemical composition of other fuels.

Electrodeposited zinc oxide nanoparticles: Synthesis, characterization, and anti-cervical cancer effects

In the present study, zinc oxide nanoparticles (ZnO NPs) were synthesized via the electrodeposition method and characterized. Then, the anticancer effects of ZnO NPs against cervical cancer HeLa cells were assessed by cell viability, oxidative stress, caspase activity, qRT-PCR, MMP, and ELISA assays. XRD analysis revealed the hexagonal wurtzite phase of ZnO. SEM image of ZnO NPs showed the homogeneous spherical/hexagonal-like structures of ZnO NPs, while TEM imaging revealed the successful synthesis of ZnO NPs with an average diameter of about 8 nm. The UV–vis absorption spectrum of ZnO NPs showed a characteristic absorption band around the wavelength of 368 nm with a band gap energy (Eg) of 3.36 eV. DLS study displayed that the obtained particle size of ZnO NPs has an average size of 29.24 nm and an average zeta potential value of −19 mV. Additionally, cellular findings indicated that the proliferation of cervical cancer HeLa cells was markedly mitigated after incubation with ZnO NPs at different concentrations of 10, 50 and 100 µg/ml, however, these concentrations were not able to trigger an apparent cytotoxic effect on HUVEC non-malignant cells. Also, it was detected that ZnO NPs led to overexpression of Bax/ Bcl-2, caspase-9/-3 genes, increased level of caspase-9/-3 activity, overproduction of MDA level, inhibition of SOD and CAT activity and reduction of GSH content, MMP collapse, and upregulation of cytoplasmic cytochrome c release. In general, these findings suggested that electrodeposited synthesized ZnO NPs can induce anticancer effects in cervical cancer HeLa cells through the mitochondrial-mediated apoptosis signaling pathway.

Synthesis and characterization of a zinc-triazole coordination complex with potent antimicrobial and anticancer properties

The synthesis, characterization, and biological appraisement of a novel coordination compound [Zn(C4N4H5O)2(H2O)2]Cl have been comprehensively studied. The compound was synthesized using N-(1H-1,2,4-triazol-3-yl) acetamide and ZnCl2·6H2O, yielding a product characterized by FT-IR, elemental analysis, thermogravimetric analysis (TGA), and single crystal X-ray diffraction. FT-IR spectra confirmed the successful coordination of the ligand to the zinc ion, with significant shifts in characteristic absorption bands such as CO (1685 cm⁻¹), CN (1624 cm⁻¹), and NH (3394 cm⁻¹). Single crystal X-ray diffraction analyses revealed that the complex crystallized in the monoclinic system with space group P21/c and forms six-membered chelate rings. The unit cell parameters were a = 6.0595(3) Å, b = 14.2956(7) Å, c = 9.4762(4) Å, and β = 93.275(4)°. Thermal analysis showed that the complex undergoes stepwise decomposition with significant mass losses at various temperature intervals, including an overall mass loss of 71.09 % between 200 °C and 885 °C. Molecular docking studies indicated strong interactions between the [Zn(C4N4H5O)2(H2O)2]Cl complex and the 6QF6 cancer-related protein antigen A4, with low binding energy values (-9.32 to -8.44 kcal/mol) suggesting high binding affinity and potential biological activity. In vitro antimicrobial screening against several pathogenic microorganisms, viz. both gram-positive and gram-negative bacteria, demonstrated that the [Zn(C4N4H5O)2(H2O)2]Cl complex exhibited superior antibacterial activity, with inhibition zone diameters of 15.3 ± 0.47 mm for Bacillus subtilis and 24.17±0.56 mm for Agrobacterium tumefaciens, compared to N-(1H-1,2,4-triazol-3-yl) acetamide alone and some standard antibiotics. These findings highlight the [Zn(C4N4H5O)2(H2O)2]Cl complex as a promising candidate for developing new antimicrobial and anticancer agents, providing a foundation for further research and potential therapeutic applications.

Viscometric studies of heavy oil in the presence of compositions consisting of amphiphilic compounds and organic solvents

The chemical composition of high-viscosity heavy oil has been studied by IR spectroscopy and X-ray fluorescence spectrometry. It is found that characteristic absorption bands are available and characterize aliphatic structures and aromatic cycles, sulfur- and organophosphorus compounds, and the presence of compounds containing heteroatoms P, V, Ca, Pd, Ni, Ru, Mo, Fe, Cu and Zn in its composition is found. The method of rotational viscometry has established the Newtonian nature of the oil flow in the studied range of the velocity up to 300 s–1. At the same time, according to the densitometry results (ρ = 0.954 g/cm3 ), studied heavy oil belongs to the bituminous type characterized by a complex rheological behavior under long- and high-term deformation conditions. In order to regulate the studied oil viscosity properties, composite additives based on amphiphilic reagents of cationic and amphoteric type and organic solvents have been developed, their influence on dynamic and kinematic viscosity has been examined. It has been established that compositions with surfactants simultaneously containing a large amount of amino and phosphate groups dissolved in a non-polar aromatic solvent (toluene) or an organic mixture (catalytic reforming gasoline) have a maximum modifying effect of the colloidal structure of bituminous oil. The interaction of functional groups of amphiphilic reagents with oil heteroatoms leads to the dispersion of resinous-asphaltene substances, a decrease in the structural and mechanical strength of the system, an increase in the molecular mobility of aggregates, which results in improving the investigated oil quality and viscosity characteristics by 7.0 and 12.6 % according to the composition efficiency index.

Resin bound gold nanocomposites assisted SE/ATR-FTIR spectroscopy for detection of pymetrozine insecticide in vegetable samples

The goal of this work was to assess the competence of organic hydrophobic resin bound gold nanocomposites (OH/R-AuNCs) for detection of pymetrozine insecticide from vegetable samples employing surface-enhanced/attenuated total reflectance-Fourier transform infrared (SE/ATR-FTIR) spectroscopy. The adsorption isotherm models, including the Langmuir, Freundlich and Temkin, are tested to reveal the interactive behaviour between the OH/R-AuNCs and pesticide. The adsorption occurs principally by London–Van der Waals dispersion interactions and hydrogen bonding interactions between the surface of OH/R-AuNCs materials and the hydrophobic part of pesticide molecule. The characteristic absorption band obtained at 3019.94 cm−1 was utilized for the quantitative analysis of pymetrozine insecticide in vegetable samples. The method was found to be accurate and precise, with mean recovery values in the range of 94.5–110 %, correlation coefficient of 0.992 %, and detection limit of 2.65 μg mL−1. The adsorption efficiency of the designed OH/R-AuNCs significantly influences the SE/ATR-FTIR response of the pymetrozine around 90 %. The optimized and validated method was applied to determine the residual concentrations of the pymetrozine that had been applied to vegetable samples.

Tailoring structural and magnetic properties: Cd²⁺ and Cu²⁺ co-doped Ni-Zn ferrite nanoparticles via sol-gel auto-combustion

In this research work, we have incorporated paramagnetic Cu2+ and diamagnetic Cd2+ cations in spinel ferrites. By adjusting the concentrations of Cu2+ and Cd2+, it is possible to achieve a balance between enhanced electrical conductivity, desired magnetic properties, and suitable structural characteristics for applications in high-frequency devices, magnetic sensors, and electromagnetic interference (EMI) suppression through a synergistic effect. The sol-gel auto-combustion method was employed to synthesize Cd²⁺ and Cu²⁺ co-doped Ni0.5Zn0.5-x-yCuxCdyFe2O4 (x = y = 0.0, 0.05, 0.1, 0.15, 0.2) ferrite nanoparticles. Structural, morphological-compositional, functional, and magnetic properties of the nanoparticles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM-EDS), Fourier-transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The XRD results confirmed the single-phase spinel structures with lattice constants increasing with higher dopant concentrations. The average crystallite sizes were found in the range of 38.14 - 42.68 nm and lattice constants in the range of 8.389 - 8.423 Å. Morphological analysis revealed agglomeration, consistent with the stoichiometric proportions during synthesis. There is a decreasing trend in nanograin sizes in the range of 40 to 73 nm with the concentration. FT-IR spectra verified the spinel structures through characteristic absorption bands around 600 cm⁻¹ and 400 cm⁻¹. Magnetic measurements indicated a decrease in saturation magnetization with increasing dopant levels indicating their potential use in electromagnetic wave absorption and magnetic memory devices.

Novel Acryloylated and Methacryloylated Nanocellulose Derivatives with Improved Mucoadhesive Properties.

In this work, three nanocellulose derivatives are synthesized with the aim of preparing new mucoadhesive materials. Nanocellulose is reacted with glycidyl methacrylate in dimethylsulphoxide, and with acryloyl and methacryloyl chloride in dimethylacetamide in the presence of 4-(N,N-dimethylamino)pyridine as a catalyst. These reactions are carried out under heterogeneous conditions, and the reaction products are characterized using various spectroscopic techniques, X-ray diffraction, atomic force microscopy, and thermogravimetric analysis. The Fourier-transform infrared spectra showed all the characteristic absorption bands typical for cellulose and also new peaks at 1720cm-1 for the carbonyl group (C═O) and 1639, 812cm-1 for the double bond (C═C). It is established that the crystal structure of the nanocellulose is slightly changed with derivatisation and the thermal stability of these derivatives increased. Mucoadhesive properties of nanocellulose and its derivatives is evaluated using the tensile test, rotating basket method, and fluorescence flow-through method. The retention of these polymers is evaluated on sheep oral mucosal tissue ex vivo using artificial saliva. Test results demonstrated that the new derivatives of nanocellulose have improved mucoadhesive properties compared to the parent nanocellulose.