Search Results (25,095)

Background/Objective: Photocatalytic oxidation is often interpreted as evidence of microplastic degradation, yet whether surface chemical modification under dry conditions corresponds to meaningful bulk polymer breakdown remains unclear. To help fill that gap, this study investigates the concentration-dependent photocatalytic aging of polystyrene (PS) microplastics incorporated into Titanium dioxide-coated hollow glass microsphere (TiO₂–HGM) composites under solid-state UV irradiation, with emphasis on distinguishing surface oxidation from bulk degradation. Methods: Thin-film composites containing 1 wt%, 5 wt%, and 10 wt% TiO₂–HGMs were exposed to UV-A irradiation (365 nm) for 183.5 h under dry conditions. Chemical and structural changes were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy. The carbonyl index (CI) was calculated from baseline-corrected integrated absorbance areas relative to an invariant aromatic reference band. Results: CI values increased from 0.483 (1 wt%) to 0.702 (5 wt%) and slightly decreased to 0.645 (10 wt%), indicating non-linear oxidation behavior and partial saturation. XPS showed a corresponding rise in the O/C ratio from 0.42 to 0.51. In contrast, UV–visible spectra exhibited minimal changes in aromatic absorption. Conclusions: Increasing photocatalyst concentration enhances surface oxidation but does not induce proportional bulk polymer degradation under solid-state conditions. Full article

Background/Objectives: The formulation development of Isotretinoin (ISN) is limited by its solubility and stability issues. This study aimed to characterise the BCS class II drug ISN, particularly the possible different solid state and formulate amorphous solid dispersion aiming for a supersaturation state. Methods: ISN’s physical states are investigated in its raw form, quench-cooled form, physical mixture with the polymer and corresponding solid dispersion form. Quench-cooled ISN was prepared in situ using DSC. Carrier stabilisation of ISN was attempted using the solid dispersion technique. Hereby, the solid dispersion of drug-polymer PVPVA at a ratio of 1:3 was prepared using the solvent evaporation method. Solid dispersion, physical mixture and raw ISN were characterised for the saturated solubility. Physical characterisation of the samples was performed using DSC, ATR-FTIR and a light microscope. Results: Two polymorphs of ISN (forms I and II) were found in the raw ISN, with form II being thermodynamically more stable. ISN possesses strong crystallinity and resistance to amorphisation under the applied quench-cooling condition without the presence of a carrier system. The conjugated polyene structure in ISN contributes to the polymorphic transformation and isomerisation. The incorporation of PVPVA in the solid dispersion system successfully improved the water solubility (sixfold) of ISN despite a combination of crystalline and amorphous components being present in the system. Conclusions: ISN is a class II drug crystal molecule. Taking advantage of solubility and possibility in the polymorphic transformation of ISN in a binary system, we concluded that ISN could potentially be formulated into its corresponding crystalline solid dispersion form. Full article

The development of microcapsules for the controlled release of active substances offers an innovative strategy in restorative dentistry, expanding the possibilities beyond traditional methods. In this study, microcapsules loaded with triethylene glycol dimethacrylate (TEGDMA) and different concentrations of hydroxyapatite (HAP)—0%, 5%, 10%, 15%, and 20%, referred to as M0, M5, M10, M15, and M20—were synthesized through in situ polymerization within an oil-in-water emulsion. Their morphology, size, and nanostructure were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of characteristic chemical bonds, whereas high-performance liquid chromatography (HPLC) quantified residual TEGDMA monomer. Low-field nuclear magnetic resonance (NMR) further confirmed the presence and the distribution of the liquid healing agent inside the microcapsules. The analyses indicated that microcapsules incorporating 20% hydroxyapatite exhibited superior structural organization and improved shell integrity, highlighting their potential in the remineralization processes. Overall, these results support the potential of HAP–TEGDMA microcapsules for incorporation into dental composites to facilitate microcrack repair and promote dental tissue regeneration. Full article

Understanding the thermal decomposition behavior and kinetic characteristics of blended biomass is crucial for optimizing thermochemical conversion processes. This study systematically investigates the synergistic pyrolysis (thermal decomposition) behavior of Salix psammophila (SP) and corn stover (CS) under a nitrogen atmosphere, with particular emphasis on process behavior and reaction kinetics (and thermodynamic feasibility). Based on elemental and proximate analyses, SP provides high calorific value and lignin content, while CS contributes high volatile matter and cellulose, enabling complementary interaction during thermal conversion. Three blending ratios (CS:SP = 2:1, 3:1, and 5:2) were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and kinetic evaluation via the Coats–Redfern, Flynn–Wall–Ozawa (FWO), and Kissinger–Akahira–Sunose (KAS) methods, together with thermodynamic parameter estimation (ΔH, ΔS, and ΔG). The results indicate that the 3:1 blend forms an optimized “continuous phase–dispersed phase” structure with an interfacial transition layer of 11–15 μm and uniformly distributed fine pores, promoting effective heat and mass transfer and facilitating volatile-release pathways across the blend interface. At a heating rate of 15 °C·min⁻¹, this blend exhibits the lowest onset temperature of rapid mass loss (T_onset, 209 °C), the highest comprehensive pyrolysis performance index (S_N, 3.01), and stable DTG profiles. Kinetic analysis confirmed that the 3:1 blend exhibits the lowest activation energy during the devolatilization stage, indicating enhanced reaction feasibility under inert conditions. The results provide mechanistic insight into biomass blending effects and offer guidance for process optimization in inert-atmosphere thermochemical conversion systems. Full article

Background: Surgical tendon rupture repair suffers from scar formation, leading to tendons with inferior mechanics and consequently to re-ruptures, as well as from adhesion formation to the surrounding tissue, reducing the range of motion. In an approach of re-purposing the phytochemical Bakuchiol to be incorporated in the polymer DegraPol^® (DP), we fabricated a novel implant material by emulsion electrospinning. Methods: To characterize the emulsion electrospun novel materials, we used Scanning Electron Microscopy (SEM) to determine the fiber diameter and pore size. In addition, we used Fourier Transformed Infrared Spectroscopy (FTIR). Finally, we planted the materials onto the chorioallantoic membrane of the chicken embryo (CAM assay) to assess tissue integration and collagen expression. Results: While the pure DP meshes were very well integrated in the CAM assay and showed a significantly higher collagen deposition within the scaffold, the DP + Bakuchiol meshes exhibited poor tissue integration, showing rather the beginning of a fibrous encapsulation. Conclusions: The novel electrospun material DP + Bakuchiol could be used as an anti-adhesion barrier to prevent tendon adhesion. Full article

Waste lignin from the hydrolysis of lignocellulosic materials is an abundant but underused by-product of the pulp and biorefinery industries. Phenolic compounds derived from lignin, rich in aromatic structures, show strong antioxidant potential and can be applied in polymer stabilization, food, and medical fields. This study evaluated the radical-scavenging activity of phenolic fractions obtained from alkaline-treated waste lignin against DPPH● and ABTS•⁺, using Trolox as a reference. Both spectrophotometric and electrochemical techniques were employed, providing deeper insight into the underlying mechanisms. Depending on the assay, the phenolic extracts demonstrated substantial radical-scavenging capacity, in some cases matching or surpassing that of Trolox. This behavior was linked to electron/proton transfer pathways, radical reactivity, and solubility effects. The combined use of multiple antioxidant tests offered a comprehensive characterization of the bioactivity of lignin-derived phenolics and supports their potential as sustainable sources of antioxidant compounds within a circular economy framework. Furthermore, the study examined how toluene-extracted phenolics affect the thermo-oxidative stability of model polyurethane films. Incorporating small amounts (1%, 3%, 5%) into the polymer matrix showed that a 1% loading provides the most effective stabilization. At higher concentrations, however, additional oxidative processes seem to be activated, as indicated by FTIR measurements and thermogravimetric analysis. Full article

In this work, sustainable aluminum-modified orange peels functionalized with graphene oxide (OP-Al-GO) were synthesized and evaluated for the removal of Methylene Violet (MV) and Reactive Red 120 (RR120) from aqueous solutions. Adsorption performance was systematically investigated in single-dye systems, binary dye mixtures, and real textile wastewater samples, and compared with that of orange peels (OP), orange peel–aluminum composite (OP-Al), and graphene oxide (GO). pH_pzc analysis clarified the surface charge of the adsorbent, while SEM and FTIR showed that the incorporation of aluminum and GO increased roughness and functional groups appearance, enhancing dye adsorption and confirming successful interactions. The OP-Al-GO composites exhibited improved removal efficiency for both dyes (64.8% for RR120 and 96.2% for MV) at pH 3.0. The presence of aluminum improved structural stability and surface charge regulation, while graphene oxide contributed to multiple adsorption mechanisms, including electrostatic attraction and π–π interactions. The adsorption kinetics were found to follow a pseudo-second-order (PSO) kinetic model for RR120 and an intraparticle-diffusion model (IPD) for MV, while isotherm analysis revealed a Langmuir behavior for MV and a Freundlich behavior for RR120. Langmuir maximum adsorption capacities were 298.7 and 10.8 mg/g for MV and RR120, respectively. High removal efficiency was maintained in binary dye mixtures, with OP-Al-GO achieving 96.9% removal of MV and 85.7% of RR120. Furthermore, the proposed adsorbent was tested on real wastewater samples, and the results highlight that the proposed adsorbents are promising, low-cost, and environmentally sustainable for textile wastewater treatment. Full article

Tyre and road wear particles (TRWPs) represent one of the most significant yet under-recognised sources of global microplastic pollution, contributing up to 28% of total emissions. Generated from the complex interaction between vehicle tyres and road surfaces, TRWPs are chemically diverse, morphologically heterogeneous, and environmentally persistent, making their detection and management particularly challenging. This review provides a critical synthesis of current knowledge on TRWP generation mechanisms, influenced by tyre composition, road types, and vehicle operation, and their environmental dispersion through air, stormwater runoff, snow removal, and roadside deposition. The chemical and physical complexity of TRWPs—often composed of rubber, bitumen, road paint, and heavy metals—necessitates multifaceted analytical approaches. We synthesise current advancements in TRWP identification techniques, including microscopy, micro-spectroscopy, and thermal desorption methods, while benchmarking their applicability using ISO standards. Furthermore, we develop an integrated framework synthesising current classification schemes, detection strategies, and regional policy responses for TRWP assessment. By identifying analytical and regulatory gaps, this review highlights the need for harmonised methodologies, improved analytical comparability, and coordinated policy interventions to address the environmental and health implications of TRWPs. Full article

This study aimed to investigate the effect of time and different disinfecting agents on nanocomposite filler composed of natural clay nanoparticles (modified and non-modified) added to maxillofacial silicone elastomers and readymade pigment additives. A total of 360 disk-shaped samples were divided into nine pigment-based groups, each with four subgroups (n = 10) exposed to different disinfectants: distilled water, 1% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and effervescent tablets. Color changes (ΔE) were measured before and after disinfection using a colorimeter. The ΔE values were assessed against perceptibility (ΔE = 1.1) and acceptability (ΔE = 3) thresholds. Nanoclay additives were also characterized using FTIR, XRD and EDX. Statistical analysis, including ANOVA and post hoc HSD tests, revealed that while all samples exhibited some color change, most remained below the acceptability threshold. Colorless silicone showed minimal, non-significant change according to perceptibility threshold (ΔE = 1.1). Blue pigments displayed significant change only with effervescent tablets. Red and mixed pigments showed perceptible changes with NaOCl, CHX, and effervescent tablets. However, nanoclay-containing specimens showed no significant perceptible alterations. Overall, despite minor perceptible changes in some pigments, all disinfecting agents tested resulted in color differences below the acceptability threshold, indicating their safe use for disinfecting maxillofacial silicone materials without compromising esthetics. Nevertheless, nanoclays are more reliable agents for the pigmentation of maxillofacial silicone as they show non-significant chromatic alteration. Full article

Background: Pantoprazole is a widely used proton pump inhibitor that is highly unstable under acidic conditions. This limits the performance of conventional formulations and typically requires enteric-coated dosage forms or alternative modified-release approaches. This study reports the development of polymeric matrix mini-tablets designed to protect pantoprazole during gastric exposure and to enable pH-dependent release under intestinal conditions. The formulations combine Eudragit^® S 100, a pH-dependent polymer, with HPMC, a hydrophilic matrix former that modulates drug release through hydration and swelling. Methods: Matrix mini-tablets were prepared by blending pantoprazole with selected excipients at optimised proportions and compressing the blends by direct compression using an eccentric tablet press. Powder blends and mini-tablets were characterised according to pharmacopoeial specifications. Analytical techniques—including High-Performance Liquid Chromatography (HPLC), Differential Scanning Calorimetry (DSC), Fourier-Transform Infrared Absorption Spectroscopy (FT-IR), Powder X-Ray Diffraction (PXRD), and Scanning Electron Microscopy (SEM)—were employed to evaluate drug content uniformity, thermal behaviour, and potential drug–excipient interactions. In vitro dissolution studies were performed under sequential pH conditions, and the release kinetics were analysed using mathematical models. Results: Dissolution testing identified formulations F2 and F6 as providing the most suitable gastro-resistant performance in the acidic stage, together with sustained release up to 24 h. Kinetic modelling supported formulation-dependent release mechanisms, and multivariate analysis (PCA) highlighted relationships between physico-mechanical attributes and drug-release behaviour. Conclusions: The proposed matrix system shows potential as a robust, coating-free platform for the modified delivery of acid-labile drugs using direct compression, simplifying manufacturing. These findings support the rational design of oral modified-release formulations based on polymeric matrices. Full article

The valorization of agro-industrial residues represents a strategic approach to advancing sustainability and circular bioeconomy principles in the food sector. Although bacterial cellulose (BC) production from waste substrates has been widely explored, limited attention has been given to the role of nitrogen source modulation in complex fermentation systems. This study evaluated passion fruit peel hydrolysate (PFPH), a cellulose- and hemicellulose-rich by-product, as an alternative carbon source for BC production using a symbiotic culture of bacteria and yeast (SCOBY) under static conditions. Acid hydrolysis and detoxification were performed to obtain fermentable sugars while minimizing inhibitory compounds. Different nitrogen sources and purification strategies were comparatively assessed. The highest purified BC yield (81 g L⁻¹ of culture medium) was obtained using ammonium sulfate, whereas sodium nitrate promoted greater impurity removal (77.51% mass reduction). Structural and chemical analyses (FTIR, XPS, and XRD) confirmed effective delignification, enhanced surface purity, and increased crystallinity. SEM revealed a homogeneous nanofibrillar network, and thermogravimetric analysis indicated thermal stability up to approximately 300 °C. Soil burial assays showed 26% mass loss after 42 days, demonstrating controlled biodegradation consistent with food packaging requirements. Overall, PFPH proved to be an efficient and sustainable substrate for BC biosynthesis. The modulation of nitrogen source significantly influenced both production yield and structural properties, highlighting the potential of this system for developing environmentally responsible biopolymer materials for food packaging applications. Full article

Chemical and biological approaches are widely applied to assess petroleum hydrocarbon contamination in soils; however, their results are often difficult to compare due to the use of fundamentally different extraction media. Chemical analytical methods typically rely on non-polar organic solvents, whereas biological toxicity assessments are based on aqueous soil extracts, reflecting water-soluble fractions of contaminants. This methodological discrepancy complicates the integrated evaluation of soil contamination and the assessment of remediation effectiveness. This study proposes an FTIR-based approach for assessing petroleum hydrocarbon contamination in sandy podzolic soil based on extraction with aqueous dimethyl sulfoxide (DMSO). The proposed method aims to reduce the methodological gap between classical chemical monitoring and aqueous-based biological assessment frameworks. The extraction performance of distilled water and aqueous DMSO solutions with different concentrations was evaluated using model soil samples artificially contaminated with crude oil. Crude oil was used as a multicomponent contaminant, whereas “petroleum hydrocarbons” refers to the operationally defined hydrocarbon fraction extracted from the soil–oil system and detected by FTIR in the C–H stretching region. Hydrocarbon extraction efficiency was assessed based on characteristic C–H stretching absorption bands in the 2800–3100 cm⁻¹ infrared region. Distilled water exhibited limited extraction capacity and rapidly reached saturation, resulting in weak and concentration-independent absorption responses. In contrast, aqueous DMSO increased the apparent solubility of hydrocarbons and yielded reproducible, concentration-dependent spectral responses. A 75% (v/v) aqueous DMSO solution was selected as a practical compromise extraction medium, increasing analytical sensitivity while remaining more compatible with aqueous conditions than conventional non-polar organic solvents. The proposed method provides a lower-hazard and methodologically coherent extraction approach for FTIR-based chemical monitoring of petroleum-contaminated soils and may facilitate improved comparability between chemical measurements and aqueous-based biological assessment approaches in integrated soil contamination and remediation studies. Full article

The objective of this study was to develop a predictive methodology for assessing the leakage phenomenon of gelatin-based soft capsules under various storage conditions. The equilibrium moisture content of the soft capsules was influenced by the temperature and humidity. The leakage phenomenon was attributable to the swelling of gelatin, as revealed by Fourier Transform Infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) imaging techniques. Additionally, the moisture diffusion mechanism of soft capsule shells was systematically investigated based on the principles of hygroscopic kinetics, enabling quantitative evaluation of their hygroscopic performance under different environmental conditions. Based on macromechanical analysis, the mechanical failure curves of soft capsule shells under different environmental conditions were investigated, enabling successful determination of the shelf life of the soft capsules. Importantly, the Arrhenius equation and the generalized Eyring model were introduced to successfully predict the occurrence of leakage during storage. The developed prediction method performs successful and accurate stability assessment under various conditions, which is crucial for the development of soft capsules. Full article

Background/Objectives: Cancer remains one of the most significant challenges in modern medicine, requiring the continuous development of novel molecular scaffolds with anticancer potential that act through multiple pathways. Heterocyclic compounds incorporating indole, triazole, oxadiazole, and thiadiazine motifs have attracted considerable attention due to their diverse pharmacological activities. This study aimed to design, synthesize, and evaluate new hybrid heterocyclic systems, including 1,2,4-triazole, 1,3,4-oxadiazole, and thiadiazine motifs, targeting liver and breast cancer. Methods: A series of indolyl-based heterocyclic compounds was synthesized using efficient and environmentally friendly protocols. Indolyl-triazol-thiadiazin-6-ol 5 was prepared via solvent-free fusion of esters 2 and 3 or the corresponding acid 4. Oxadiazole derivatives were produced by reacting hydrazide intermediates with carbon disulfide. Triazole derivatives were synthesized via cylization of thiosemicarbazide 9 in aqueous KOH (4.0 N). Structural characterization was performed using Fourier Transform InfraRed (FTIR), ¹H and ¹³C NMR spectroscopy, and electron impact mass spectrometry (EIMS). Cytotoxic activity was evaluated against liver and breast cancer cell lines, and VEGFR-2 kinase inhibition was assessed for selected derivatives. Results: The synthesized compounds demonstrated notable cytotoxicity activity, with compounds 4, 5, and 9 exhibiting IC₅₀ values in the low micromolar range. Enzymatic assays revealed that compounds 4 and 9 showed strong VEGFR-2 inhibition (97.9% and 96.4%, respectively), indicating apoptosis-inducing effects. Conclusions: The synthesized indolyl-based hybrid heterocycles represent a promising chemotype with in vitro cytotoxic activity and VEGFR-2 inhibitory effects, supporting further investigation, optimization, and mechanistic studies to evaluate their potential lead for anticancer drug development. Full article

The use of chemical fertilizers has led to significant environmental pollution. An alternative to these fertilizers is the use of natural compounds, such as phytohormones, which promote germination and crop development. However, environmental factors can affect natural compounds, reducing their effectiveness. Therefore, increasing their stability without decreasing their activity to improve crop quality is essential. This study produced and characterized chitosan and sodium tripolyphosphate (TPP) nano-microparticles (NMP) loaded with Bacillus subtilis extract and evaluated their impact on tomato seed germination. We employed two experimental designs (Box–Behnken and Box–Hunter–Hunter) to determine the optimal production conditions and characterized the NMP using DLS, SEM, and FTIR. The optimal treatment consisted of 8 min of homogenization, followed by 8 min of ultrasound at a 70% amplitude, resulting in a particle size of 330.7 nm, a polydispersity index of 0.25, a zeta potential of 34.3 mV, and an encapsulation efficiency of 68.8%. The NMP loaded with bacterial extract was applied to tomato seeds as a 50% dilution pretreatment. NMP achieved the best results, with a 72% germination rate (1.6 seeds per day) and an average germination time of 3.8 days. It is concluded that the experimental designs helped improve particle properties and that the chitosan and TPP coating enhances the stability and activity of the bacterial extract, potentially benefiting agronomic applications. Full article