Search Results (434)

Drying is ubiquitous. However, its influence on surface speciation has been seldom studied. Through an in situ Attenuated Total Reflection–Infrared (ATR-IR) spectroscopy analysis of the drying of molybdate solutions on a lepidocrocite particle film, the change in surface speciation is followed. No formation polymolybdates nor precipitate are observed upon drying at pH 8. An in situ washing of the dried solid/solution interface unveils the existence of surface outer-sphere and inner-sphere complexes. Decreasing the molybdate concentration highlights a saturation effect of the surface upon drying. Moreover, the careful analysis of substrate IR bands showed non-uniform drying which is an important insight to understand dehydration chemistry. The remaining molybdate ions at the surface as inner-sphere complexes are present as binuclear monodentate complexes stabilized by sodium. Full article

Background/Objectives: Fenbendazole is a potential cancer treatment and a proven antiparasitic in veterinary applications. However, its poor water solubility limits its application. In this study, potential fenbendazole solubility enhancement was investigated through size reduction methods. The effect of the presence of Soluplus^® on solubility was investigated as well. Methods: Solubility enhancement was explored using microfluidization and ultrasonication techniques. These techniques were applied to fenbendazole alone and in combination with Soluplus^®. UV–Vis spectroscopy was used to determine solubility. Possible chemical reactions were checked using Fourier transform infrared spectroscopy (FT-IR). Differential scanning calorimetry (DSC) was conducted to analyze the physical structure and crystallinity of the samples. Scanning electron microscopy (SEM) was also utilized for characterization of the effect of the treated formulations and the size reduction method on morphology. The elements present in samples were identified with energy-dispersive X-ray spectroscopy (EDX) combined with SEM. A comparison of crystalline structure between the products was performed via X-ray powder diffraction (XRPD). Dynamic light scattering (DLS) was also used to measure the samples’ average particle size at different stages. Results: Both ultrasonication and microfluidization led to marginal increases in the solubility of neat fenbendazole. In contrast, formulations processed in the presence of Soluplus^® demonstrated a greater enhancement in solubility. However, solubility improvement was not retained in the dried samples. The post-drying samples, irrespective of the presence of Soluplus^®, showed nearly the same solubility as neat fenbendazole. Conclusions: Size-reduction methods, particularly when combined with Soluplus^®, improved the solubility of fenbendazole. However, drying appeared to reverse these gains, regardless of the method used. Full article

To identify the optimal drying methods for turnip slices, vacuum freeze-drying (VFD), air impingement drying (AID), infrared-assisted hot air drying (IR-HAD), and conventional hot air drying (HAD) were evaluated. The physicochemical properties of dried samples were comprehensively assessed under varied drying conditions. The results demonstrated that AID achieved the shortest drying time (240 min). At identical temperatures, AID samples exhibited significantly lower total color difference (ΔE) compared with IR-HAD and HAD, alongside superior retention of total phenols and enhanced antioxidant activity. VFD yielded the highest quality attributes, including optimal rehydration capacity, maximal phenol retention, and the strongest antioxidant activity (DPPH: 16.56 ± 0.26 μmol Trolox/g; FRAP: 13.99 ± 0.04 μmol Trolox/g). SEM analysis revealed that VFD produced a loose, porous microstructure, explaining its enhanced rehydration. Overall, both AID (efficiency) and VFD (quality) show promise for industrial turnip processing. Full article

Collagen-based biomaterials are increasingly explored in dentistry for their ability to deliver drugs locally and support healing. In this study, we developed chlortetracycline-loaded collagen sponges aimed at preventing postoperative infections. Five formulations were prepared by lyophilization, each with the same collagen-to-drug ratio but different glutaraldehyde (GA) concentrations: 0%, 0.25%, 0.5%, 0.75%, and 1% (w/w) relative to dry collagen. The sponges were characterized using FT-IR and UV–VIS–NIR spectroscopy, and their swelling capacity, enzymatic stability, and drug release kinetics were evaluated. Antibacterial activity was tested against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. Statistical differences between formulations were assessed using one-way ANOVA followed by Tukey’s post hoc test (p < 0.05). All sponges released the antibiotic rapidly within the first 60 min, followed by a sustained release for up to 10 h. The non-crosslinked sponge showed the highest antimicrobial effect, while the 0.25% GA formulation offered a good balance between stability and bioactivity. While higher cross-linking enhanced structural stability, it progressively reduced antimicrobial efficacy, highlighting a crucial design trade-off. These findings underline the need to fine-tune cross-linking conditions to achieve both durability and strong antimicrobial action in collagen-based drug delivery systems for dental applications. Full article

This study aims to assess the by-products generated through the thermal and catalytic pyrolysis of the organic matter and paper fractions of municipal solid waste (MSW) in different socioeconomic regions, through the yields of reaction products (bio-oil, biochar, H₂O, and gas), acid value and chemical composition of bio-oils, and characterization of biochar, on a laboratory scale. The organic matter and paper segregated from the gravimetric composition of the total waste sample were subjected to drying, crushing, and sieving pre-treatment. The experiments were carried out at 450 °C and 1.0 atmosphere, and at 400 °C and 475 °C and 1.0 atmosphere, using a basic catalyst, Ca(OH)₂, at 10.0% by mass, in discontinuous mode. The bio-oil was characterized by acidity value and the chemical functions present in the bio-oil identified by FT-IR, NMR, and composition by GC-MS. The biochar was characterized by SEM/EDS and XRD. The bio-oil yield increased with the addition of the catalyst and the pyrolysis temperature. For catalytic pyrolysis, bio-char and gas yields increased slightly with the Ca(OH)₂ content, while bio-oil and H₂O phases remained constant. The GC-MS of the liquid reaction products identified the presence of hydrocarbons and oxygenates, as well as nitrogen-containing compounds, including amides and amines. The acidity of the bio-oil decreased with the addition of the basic catalyst in the process. The concentration of hydrocarbons in the bio-oil appeared with the addition of the catalyst in the catalytic pyrolysis process as the catalytic deoxygenation of fatty acid molecules occurred, through decarboxylation/decarbonylation, producing aliphatic and aromatic hydrocarbons, introducing the basic catalyst into the thermal process. Full article

Background: With the increasing shift in drug design away from classical drug targets towards the modulation of protein-protein interactions, synthetic peptides are gaining increasing relevance. The synthesis and purification of peptides via solid-phase peptide synthesis (SPPS) strongly rely on trifluoroacetic acid (TFA) as a cleavage agent and ion-pairing reagent, respectively, resulting in peptides being obtained as TFA salts. Although TFA has excellent properties for peptide production, numerous studies highlight the negative impact of using peptides from TFA⁻ salts in biological assays. Methods: Investigated peptides were synthesized via SPPS and the TFA⁻ counterion was exchanged for Cl⁻ via freeze-drying in different concentrations of HCl. Detection and quantification of residual TFA⁻ were carried out via FT-IR, ¹⁹F-NMR, and HPLC using an evaporative light-scattering detector (ELSD). A liposomal fluorescence assay was used to test for the influence of the counterion on the peptides’ passive membrane permeability. Results: All TFA⁻ detection methods were successfully validated according to ICH guidelines. TFA⁻ removal with 10 mM HCl was determined to be the optimal condition. No impact on peptide purity was observed at all HCl concentrations. Influences on permeability coefficients depending on peptide sequence and salt form were found. Conclusions: This study presents a systematic investigation of the removal of TFA⁻ counterions from synthetic peptides and their replacement with Cl⁻ counterions. Detected counterion contents were used to understand the impact of sequence differences, especially positive charges, on the amount and potential localization of counterions. Our findings emphasize the importance of counterion quantification and specification in assays with synthetic peptides. Full article

Aimed at developing an economical and efficient biosorbent for the adsorption and separation of rare earth ions, this study employed Spirulina dry powder biomass as a biosorbent to investigate its removal performance for Pr³⁺ in aqueous solutions. Experimental results demonstrated that under optimized conditions (pH = 5, adsorbent dosage = 2.0 g/L, initial Pr³⁺ concentration = 100 mg/L, and adsorption time = 60 min), the removal efficiency of Pr³⁺ reached 79.0%. FT-IR and XPS characterization confirmed the participation of various functional groups on the Spirulina surface in the adsorption process. When 0.1 mol/L HNO₃ was used as the desorption agent, the desorption rate of Pr³⁺ from Spirulina reached 91.7%, demonstrating excellent regeneration performance. At different temperatures (298–318 K), the adsorption data were fitted using Langmuir, Freundlich, Dubinin–Radushkevich, and Redlich–Peterson models. Among them, the Langmuir model (R² ranged from 0.993 to 0.999) provided the best fit, and the adsorption capacity of Spirulina for Pr³⁺ was in the range of 51.10 to 55.31 mg/g. Kinetic studies revealed that the pseudo-second-order model (R² = 0.999) best described the adsorption process, with a rate constant of 0.054 g/(mg·min) (R² was 0.999) at an initial Pr³⁺ concentration of 300 mg/L, indicating chemisorption-controlled behavior. Thermodynamic parameter analysis showed that within the experimental temperature range, ΔG⁰ < 0 and ΔS⁰ > 0, confirming that the adsorption process was spontaneous and endothermic. This study provides a novel technical approach for the green recovery of rare earth elements and highlights the potential of Spirulina biomass in rare earth resource recycling. Full article

More than half of the world’s rivers are intermittent, and climate change is increasing their intermittency, affecting water resources and ecosystems. In Taiwan, steep topography and uneven rainfall have led to increased intermittency in some areas, reflecting changes in hydrological conditions. Using streamflow data, this study applied intermittency ratio (IR), modified 6-month dry period seasonality (SD6), and trend analysis, as well as watershed properties and climate indices. Results showed that 92% of stations had low flows for less than 20% of the time. The dry season was mainly from November to April, and intermittency was spatially affected mainly by upstream soil moisture, moderately by potential evapotranspiration and infiltration, and less by actual evapotranspiration and catchment area. Intermittency increased in the east and decreased in the west. It was negatively correlated with upstream soil moisture and strongly associated with rainfall frequency, especially the proportion of days with precipitation less than 1 mm. These patterns highlight regional differences in river responses to climate. Full article

In this study, we designed an injectable skin-rejuvenating formulation based on polyethylene glycol–polycaprolactone–polyethylene glycol (PEG-PCL-PEG) copolymers to provide a synergistic combination of biocompatibility, antioxidative capacity, and regenerative potential. Through the systematic optimization of the precursor molar ratio and molecular weight, well-defined PEG-PCL-PEG copolymers were synthesized and structurally characterized using gel permeation chromatography (GPC), proton nuclear magnetic resonance (¹H-NMR), and Fourier transform infrared (FT-IR) spectroscopy. An optimized precipitation and drying protocol effectively reduced residual solvents, as confirmed by gas chromatography (GC). Idebenone was incorporated as an antioxidant to prevent skin aging, while hyaluronic acid (HA), L-arginine, and glycerin were included to promote collagen regeneration. In vitro assays demonstrated that idebenone-loaded samples exhibited prolonged intracellular antioxidant activity with low cytotoxicity. The collagen-promoting formulation, containing HA, glycerin, and L-arginine, enhanced the expression of transforming growth factor-β (TGF-β) and type III collagen (COL3) while suppressing inflammatory genes, suggesting a favorable environment for extracellular matrix remodeling. In vivo evaluation corroborated these outcomes, showing angiogenesis, collagen reorganization, and progressive dermal thickness. Histological analysis further confirmed sustained matrix regeneration and tissue integration. These results highlight the potential of PEG-PCL-PEG-based injectables as a multifunctional platform for collagen regeneration, offering a promising strategy for both cosmetic and clinical applications. Full article

The construction industry is the main consumer of mineral resources. At the same time, the Portland cement (PC) industry occupies a leading position, using expensive, high-quality raw materials. This is due to the high rate of construction in different areas (industrial, civil, road construction, etc.). The widespread application of PC is due primarily to the strength and durability of composite materials based on it. Taking into account their specific purpose, PC-based composites are usually optimized to achieve specified characteristics and rational use of raw materials. To reduce PC consumption and justify the possibility of its use in complex binders, this manuscript analyzes the composition of a functional polymer–mineral additive; the nature and mechanisms of its interaction with PC depend on the method of introducing the additive (dry mixing/joint grinding of the clinker–gypsum mixture with the additive at the stage of binder preparation). Based on the data of XRD, IR, and SEM analysis, as well as taking into account patent information, the composition of the additive was clarified. The combined application of the above methods allowed us to establish the uniformity of the additive distribution in the binder depending on the introduction method and to evaluate the effect of each additive component and its mutual impact on the processes occurring during cement hydration. As a result, it was established that the most effective introduction method is combined grinding. A phenomenological model of the structure formation of additives containing cement paste is proposed. The binder production by the combined grinding method promotes the intensification of the processes occurring during hydration, as evidenced by the data of qualitative and quantitative XRD, IR, and DTA analysis, differential scanning calorimetry (DSC), and TGA analysis. Full article

The world’s energy demand increases daily, fostering the search for renewable fuels to reconcile production needs with environmental sustainability. To prevent the severe atmospheric impact of fossil fuels, reducing greenhouse gas emissions is both essential and urgent, reinforcing the necessity of developing and adopting renewable fuel alternatives. Therefore, this work aimed to produce bio-oil through sugarcane bagasse fast pyrolysis. The methodology is based on fast pyrolysis operation in a fluidized bed reactor (pilot plant) as a thermochemical method for bio-oil production. This research required the conditioning of the raw material for system feeding, along with optimizing key variables, operating temperature, airflow, and sugarcane bagasse feed rate, to achieve improved yields compared to previous studies conducted in this pilot plant. The sugarcane bagasse was conditioned through drying and milling, followed by characterization using various analytical methods, including calorific value, thermogravimetric analysis (TGA), particle size analysis by laser diffraction (Mastersizer—MS), and ultimate analysis (determining carbon, hydrogen, nitrogen, sulfur, and oxygen by difference). The bio-oil produced showed promising yield results, with a maximum estimated value of 61.64%. Fourier Transform Infrared Spectroscopy (FT-IR) analysis confirmed the presence of aromatic compounds, as well as ester, ether, carboxylic acid, ketone, and alcohol functional groups. Full article

Polymer brushes (PBs) are transformative surface-modifying nanostructures, yet their synthesis via controlled methods like copper-mediated surface-initiated atom-transfer radical polymerization (Cu⁰-SI-ATRP) faces reproducibility challenges due to a lack of understanding of parameter interdependencies. This study systematically evaluates the Cu⁰-SI-ATRP process for polyacrylamide brushes (PAM-PBs), aiming to clarify key parameters that influence the synthesis process. This evaluation followed a step-by-step characterization that tracked molecular changes through infrared spectroscopy (IR) and surface development by contact angle (CA) through two different mixing methods: ultrasonic mixing and process simplification (Method A) and following literature-based parameters (Method B). Both methods, consisting of surface activation, 3-aminopropyltriethoxysilane (APTES) deposition, bromoisobutyryl bromide (BiBB) anchoring, and polymerization, were analyzed by varying parameters like concentration, temperature, and time. Results showed ultrasonication during surface activation enhanced siloxane (1139→1115 cm⁻¹) and amine (1531 cm⁻¹) group availability while reducing APTES concentration to 1 Vol% without drying sufficed for BiBB anchoring. BiBB exhibited insensitivity to concentration but benefited from premixing, evidenced by sharp C–Br (~1170 cm⁻¹) and methyl (3000–2800 cm⁻¹) bands. Additionally, it was observed that PAM-PBs improved with Method A, which had reduced variance in polymer fingerprint regions compared to Method B. Adding to the above, CA measurements gave complementary step-by-step information along the modifications of the surface, revealing distinct wettability behaviors between bulk PAM and synthesized PAM-PBs (from 51° to 37°). As such, this work identifies key parameter influence (e.g., mixing, BiBB concentration), simplifies steps (drying omission, lower APTES concentration), and demonstrates a step-by-step, systematic parameter decoupling that reduces variability. In essence, this detailed parameter analysis addresses the PAM-PBs synthesis process with better reproducibility than the previously reported synthesis method and achieves the identification of characteristic behaviors across the step-by-step process without the imperative need for higher-cost characterizations. Full article

Pectin–tomato paste edible films with potential antioxidant activity were studied. Initially, the films were formed by drying at 40 °C in the presence and absence of glycerol. The effect of drying temperature on several physicochemical, mechanical, and optical properties of glycerol films formed after drying at 40, 50, and 60 °C was investigated. Finally, films formed at different drying conditions (namely F40, F50, and F60) sharing the same antioxidant activity (44.28–45.53%) were studied in terms of their surface pH; solubility; folding endurance; antimicrobial, dynamic mechanical, and barrier properties; contact angle; and FT-IR. Their thickness, weight, opacity, strength, stiffness, and antioxidant activity (AA) [a*] increased with increasing tomato paste content, whereas [L*] decreased. The moisture content was statistically affected by both the presence of glycerol and the drying temperature. AA decreased as drying temperature increased. Overall, the thickness varied from 45 to 182.31 μm, weight from 0.27 to 1.24 g, moisture content from 20.74 to 56.66%, stress from 189 to 959 kPa, Young’s modulus from 86 to 382 kPa, and AA from 16.9 to 53%. In the last step, F60 was less hydrophilic, had a greater density, and better barrier properties, whereas F50 was stiffer and the least strong. Our findings provide information regarding the selection of an optimum drying temperature for pectin-based films with antioxidant properties. Full article

Background/Objectives: Chronic lung diseases are among the leading causes of death worldwide. In the treatment of these diseases, non-steroidal anti-inflammatory drugs can be effective. We have previously developed an excipient formulation alongside a modern manufacturing protocol, which we aim to further investigate. We have chosen two new model drugs, meloxicam (MX) and its water-soluble salt, meloxicam-potassium (MXP). The particles in dry powder inhaler (DPI) formulation were expected to have a spherical shape, fast drug release, and good aerodynamic properties. Methods: The excipients were poloxamer-188, mannitol, and leucine. The samples were prepared by spray drying, preceded by solution preparation and wet grinding. Particle size was determined by laser diffraction, shape by scanning electron microscopy (SEM), crystallinity by powder X-ray diffraction (PXRD), interactions by Fourier-transform infrared spectroscopy (FT-IR), in vitro drug dissolution by paddle apparatus, and in vitro aerodynamic properties by Andersen cascade impactor and Spraytec^® device. Results: We achieved the proper particle size (<5 μm) and spherical shape according to laser diffraction and SEM. The XRPD showed partial amorphization. FT-IR revealed no interaction between the materials. During the in vitro dissolution tests, more than 90% of MX and MXP were released within the first 5 min. The best products exhibited an aerodynamic diameter of around 4 µm, a fine particle fraction around 50%, and an emitted fraction over 95%. The analysis by Spraytec^® supported the suitability for lung targeting. Conclusions: The developed preparation process and excipient system can be applied in the development of different drugs containing DPIs. Full article

This study presents a novel approach for enhancing the survivability of Lactiplantibacillus plantarum BXM2 using bamboo shoot-derived nanocellulose hydrogels. Nanocellulose hydrogels, composed of cellulose nanofibers (CNFs), cellulose nanocrystals (CNCs), and polyvinyl alcohol (PVA), were developed as protective matrices for probiotics. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed the successful formation of hydrogen-bonded networks between PVA and nanocelluloses, while scanning electron microscopy (SEM) revealed that the ternary PVA-CNF-CNC hydrogel exhibited a dense, hierarchical porous structure, effectively encapsulating probiotics with an encapsulation efficiency of 92.56 ± 0.53%. Under simulated gastrointestinal digestion, the encapsulated probiotics maintained 8.04 log CFU/g viability, significantly higher than that of free bacteria (3.54 log CFU/mL). The hydrogel also enhanced heat tolerance (6.58 log CFU/mL at 70 °C) and freeze-drying survival (86.92% viability), outperforming binary systems. During 60-day storage at 4 °C and 25 °C, encapsulated probiotics retained viability above the critical threshold (≥6 log CFU/unit), whereas free cells declined rapidly. These findings highlight the potential of PVA-CNF-CNC hydrogel as an efficient delivery system to improve probiotic stability in food applications. Full article