Search Results (351)

Natural rubber (NR) possesses excellent comprehensive properties and plays an irreplaceable role in both national defense and people’s livelihood. In recent years, lignin, as a new development trend, has emerged as a reinforcing filler in natural rubber, partially replacing traditional carbon black, or serving as an antioxidant in rubber. However, lignin, a polar biomass filler, exhibits poor compatibility with non-polar natural rubber. To address the compatibility issue between the two, this paper adopts an in situ method, utilizing formic acid and hydrogen peroxide to modify natural rubber into two types of epoxidized natural rubber (ENR) with different degrees of epoxidation (E-25% and E-45%). Subsequently, through wet mixing, it is combined with a lignin aqueous solution (20 parts), and ethanol is used as a flocculant to prepare lignin/ENR composite rubber materials. Comprehensive characterization of the composite rubber materials reveals that after epoxidation modification, the interfacial compatibility between lignin and natural rubber has been significantly improved. Wet mixing also effectively enhances the dispersibility of lignin in the rubber matrix. Compared to natural rubber, the composite material with an epoxidation degree of 25% exhibits significantly superior mechanical properties and thermal stability. The tensile properties of the composite rubber increase from 29.4 MPa to 36.2 MPa, indicating the significant reinforcing effect of lignin. This study aims to investigate the effects of the epoxidation degree (25% and 45%) of epoxidized natural rubber (ENR) and the mixing method on the compatibility and reinforcement performance of composite rubber, providing a new method for preparing high-performance lignin/ENR composites. Full article

A novel near-infrared (NIR) squaraine-based chemosensor, SQ-68, has been designed and synthesized for the sensitive and selective detection of Cu²⁺ and Ag⁺ ions, offering a compact solution for multi-analyte sensing. SQ-68 demonstrates high selectivity, with its performance influenced by the solvent environment: It selectively detects Cu²⁺ in acetonitrile and Ag⁺ in an ethanol–water mixture. Upon binding with either ion, SQ-68 undergoes significant absorption changes in the NIR region, accompanied by visible color changes, enabling naked-eye detection. Spectroscopic studies confirm a 1:1 binding stoichiometry with both Cu²⁺ and Ag⁺, accompanied by hypochromism. The detection limits are 0.09 μM for Cu²⁺ and 0.38 μM for Ag⁺, supporting highly sensitive quantification. The sensor’s practical applicability was validated in real water samples (sea, lake, and tap water), with recovery rates ranging from 73–95% for Cu²⁺ to 59–99% for Ag⁺. These results establish SQ-68 as a reliable and efficient chemosensor for environmental monitoring and water quality assessment. Its dual-analyte capability, solvent-tunable selectivity, and visual detection features make it a promising tool for rapid and accurate detection of heavy metal ions in diverse aqueous environments. Full article

In this work, biochars were produced by pyrolysis of exhausted olive pomace and evaluated as low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. The biochar obtained at 400 °C for 1 h, which exhibited the best adsorption performance, was characterized by FTIR, N₂ adsorption–desorption isotherms, SEM-EDX, and proximate analysis, revealing a mesoporous structure with a relatively low specific surface area but enriched in surface functional groups, likely due to the partial degradation of lignocellulosic components. Adsorption experiments were conducted to optimize operational parameters such as solid particle size (2–3 mm), agitation speed (75 rpm), and bioadsorbent dosage (1 g per 0.05 L of MB solution), which allowed for dye removal efficiencies close to 100%. Kinetic studies showed that MB adsorption followed a pseudo-second-order model, while equilibrium data at 30 °C were best described by the Langmuir isotherm (R² = 0.999; SE = 4.25%), suggesting monolayer coverage and strong adsorbate–adsorbent affinity. Desorption trials using water, ethanol, and their mixtures resulted in low MB recovery, whereas the addition of 10% acetic acid significantly improved desorption performance. Under optimal conditions, up to 52% of the retained dye was recovered. Full article

This study investigates the antioxidant, antimicrobial, and antitumor activities of Taraxacum officinale (Dandelion) and Artemisia annua (Sweet Wormwood) extracts, along with their role in the green synthesis of gold (AuNPs) and silver nanoparticles (AgNPs). Bioreduction was achieved using aqueous and ethanolic extracts (100 mg/mL), enabling solvent-dependent comparisons. Nanoparticles were characterized using ultraviolet–visible spectroscopy (UV–Vis), fluorescence spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Each technique revealed complementary aspects of nanoparticle morphology, size, and stability, with UV–Vis indicating aggregation states and DLS confirming solvent-related size variation even at 3–5% ethanol. Gold nanoparticles synthesized from Dandelion showed strong antibacterial activity against Staphylococcus aureus, while silver nanoparticles from both plants were effective against Escherichia coli. Cytotoxicity assays indicated that silver nanoparticles obtained from ethanolic Dandelion extract containing 3% ethanol in aqueous solution (AgNPsE_ETOH3%-D) significantly reduced LoVo (p = 4.58 × 10⁻³) and MDA-MB-231 (p = 7.20 × 10⁻⁵) cell viability, with high selectivity indices (SI), suggesting low toxicity toward normal cells. Gold nanoparticles synthesized from aqueous Dandelion extract (AuNPsEaq-D) also showed favorable SI values (2.16 for LoVo and 8.41 for MDA-MB-231). Although some formulations demonstrated lower selectivity (SI < 1.5), the findings support the therapeutic potential of these biogenic nanoparticles. Further in vivo studies and pharmacokinetic evaluations are required to validate their clinical applicability. Full article

Albumin-based nanoparticles are promising drug delivery systems due to their biocompatibility, biodegradability, and ability to improve targeted drug release. Among various preparation methods, radiation-induced cross-linking in the presence of ethanol has been proposed in the literature as an effective method for producing protein nanoparticles with preserved bioactivity and controlled size. However, the mechanisms by which ethanol radicals contribute to protein aggregation remain insufficiently understood. In this study, we investigate the role of ethanol in the aggregation of albumins to determine whether its presence is necessary or beneficial for nanoparticle formation. Using pulse radiolysis, spectroscopy methods, resonance light scattering (RLS), and near-infrared (NIR) spectroscopy, we examined aqueous ethanol solutions of albumins before and after irradiation. Our results show that ethanol concentrations above 40% (v/v) significantly promote both radiation-induced and spontaneous protein aggregation. Mechanistic analysis indicates that ethanol radicals react with albumin similarly to hydrated electrons, mainly targeting disulfide bridges. This reaction leads to the formation of sulfur-centered radicals and the formation of intermolecular disulfide bonds that stabilize protein nanostructures by excluding the formation of dityrosine bridges, as described in the literature. In contrast, ethanol concentration below 40% does not favor the radiation-induced aggregation compared to the solution containing t-BuOH. These results provide novel insights into the role of organic cosolvents in protein aggregation and contribute to a broader understanding of the mechanisms of formation of albumin-based nanoparticles using ionizing radiation. Full article

The cupric ion reducing antioxidant capacity (CUPRAC) assay, originally developed to measure the antioxidant capacity of nutritional products spectrophotometrically, utilized water as the solvent for Trolox. Due to the limited solubility of Trolox in aqueous solutions, the optimization of the solvent system was investigated to enhance analytical performance. Solvent combinations consisting of methanol, ethanol, and water were evaluated to identify the mixture that ensures complete dissolution and maximum absorbance signal, using a ternary plot diagram and mathematical modeling. A methanol/water ratio of 0.64:0.36 was identified as the optimal solvent composition. Under these conditions, the CUPRAC assay demonstrated a linear range of 0–50 μM, a limit of detection of 0.91 μM, and a limit of quantification of 2.75 μM. Precision, expressed as the coefficient of variation, was below 5%, and accuracy—defined as the deviation between nominal and back-calculated concentrations—remained within ±7.0%, in accordance with the variation range recommended by the International Committee on Harmonization. The estimated molar absorption coefficient at the optimized solvent ratio (ε_Trolox = 2.62 × 10⁴ L mol⁻¹ cm⁻¹) was applied to determine the antioxidant capacity of fish commercial feed ingredients containing a mixture of rosemary and olive extracts. Full article

Selecting factors that significantly affect the extraction process and optimizing them are essential to obtain high extraction efficiency. This study aimed at optimizing the ultrasonic-assisted extraction (UAE) of polyphenols from Romanian blackthorn fruits using aqueous solutions of ethanol as green extraction solvents. Six process factors, including solvent/plant material ratio (R_LS = 4.95–15.1 cm³/g), ethanol concentration in the extraction solvent (c_et = 16.4–83.6%), extraction temperature (t = 30–70 °C), pH of the solvent (pH = 2–7), amplitude of the ultrasonic probe (A = 30–70%), and extraction time (τ = 5–15 min), were screened and optimized based on a Plackett–Burman design (PBD) and a central composite design (CCD). Statistical analysis indicated that R_LS, c_et, and t significantly affected the process response variables in terms of total phenolic content (TPC), total anthocyanin content (TAC), and antioxidant capacity (AC). Under optimal conditions (R_LS,opt = 15.1 cm³/g, c_et,opt = 33.2%, t_opt = 66.8 °C, pH_opt = 7, A_opt = 50%, and τ_opt = 10 min), the following levels of response variables were experimentally determined: TPC_opt = 14.45 ± 0.718 mg GAE/g DM, TAC_opt = 0.405 ± 0.057 mg C3GE/g DM, and AC_opt = 16.75 ± 1.144 mg TE/g DM. Six phenolic compounds were identified in the extract obtained at optimal levels of process factors, i.e., rutin (7.12 ± 0.06 mg/100 g DM), protocatechuic acid (6.83 ± 0.01 mg/100 g DM), neochlorogenic acid (4.88 ± 0.01 mg/100 g DM), vanillic acid (3.70 ± 0.01 mg/100 g DM), chlorogenic acid (1.93 ± 0.02 mg/100 g DM), and caffeic acid (1.51 ± 0.01 mg/100 g DM). Full article

Cocoa is a rich source of health-promoting polyphenols such as flavanols. These compounds can be separated from other matrix constituents using various adsorbents or resins. Seven different macroporous resins (Amberlite^® XAD-2, XAD-4, XAD-7, XAD-7HP, XAD-16, Sepabeads^TM SP207, and Diaion^® HP2-MG) were evaluated for their adsorption and desorption properties for the enrichment of flavonoids from an aqueous cocoa (Theobroma cacao L.) extract. The influence of adsorption and desorption temperatures and the concentration of the desorption solvent (a hydroalcoholic solution) were investigated by static adsorption and desorption methods. The results of the resin comparison showed that the adsorbent XAD-7HP had the best adsorption characteristics, with an adsorption capacity of 39.8 mg ECE/g. XAD-7HP was found to be the most suitable adsorbent, and 70% ethanol was the best desorbing solvent, based on static experiments. In addition, the optimal conditions for the adsorption of flavonoids were obtained at a temperature of 30 °C, where equilibrium was reached after 80 min. The static adsorption process was well-described by a pseudo-second-order kinetics model, while the adsorption isotherm data were fitted well by the Freundlich isotherm model. Further dynamic adsorption and desorption characteristics were evaluated on a packed glass column, and it was shown that XAD-7HP could enrich the flavanol content by 5.03-fold, with a dry matter content of 456.05 mg/mL (as estimated by the degree of DP1–DP7 procyanidin polymers using ultra-pressure liquid chromatography). Full article

Mogroside V crude extract from Siraitia grosvenorii has many pharmacological effects, such as anti-diabetes, antioxidant, etc. It is being used as a kind of natural sweetener in more and more countries. The improvement of Mogroside V purity can greatly promote the utilization value of Siraitia grosvenorii and the quality of related products. For this paper, a boronic acid-functionalized silica gel adsorbent (SiO₂-GP-APBA) was synthesized and applied for the first time in the purification of mogroside V from the crude extract of Siraitia grosvenorii. It was demonstrated that it was 30–100 μm with 163.1 μmol/g of boronic acid groups on the surface of silica gel and stable at below 380.20 °C. Its maximum adsorption capacity to mogroside V was up to 206.74 mg/g at room temperature. After the saturated absorption from the crude extract of Siraitia grosvenorii in a pH 3 solution, 96.36% mogroside V could be released from SiO₂-GP-APBA using a pH 7 aqueous solution, which was better than ethanol. The purity of mogroside V was significantly increased from 35.67% to 76.34%. Semi-preparative HPLC could further improve the purity of mogroside V to 99.60%. Additionally, the direct inhibition effect of the mogroside V on α-glucosidase was determined for the first time. Its inhibitory constant was 46.11 μM, indicating mogroside V was beneficial for the treatment of diabetes. Full article

The main objective of this research was to correlate the equilibrium solubility of sodium sulfadiazine in several {ethanol (EtOH, 1) + water (2)} mixtures reported in mass/volume and mass/mass percentages at different temperatures. Aqueous solubility of sodium sulfadiazine decreases almost linearly with decreasing temperature, but it decreases non-linearly with the addition of EtOH to water. Logarithmic solubility was adequately correlated with a bivariate model involving temperature and mixture composition. These solubility results were also well correlated with the Jouyban–Acree-based models. Moreover, an adapted version of the Jouyban–Acree model was used to represent the density of the saturated solvent mixtures at different temperatures. Furthermore, the apparent specific volumes of this drug at saturation were also calculated from densities of saturated solutions and cosolvent mixtures free of drug as well as from the respective mixture compositions. These findings provide valuable insights into the solubility and volumetric behavior of sodium sulfadiazine, which could be useful for pharmaceutical formulation and process optimization. Full article

Accurately identifying local interactions such as hydrophilicity and hydrophobicity is of critical importance in regulating the functions of amphiphilic biomolecules, but in situ identification methods for such interactions are still lacking. This study proposes a probe based on carbonyl (C=O) stretching vibration to study the hydrophilic and hydrophobic interactions in amphiphilic alcohol–water systems. A combination of theoretical calculations and Raman spectroscopy experiments is employed to investigate the molecular interactions of ethyl acetate C=O in an ethanol aqueous solution, as well as the reasons behind the splitting of spectral peaks. The results indicate that the spectral peak splitting of the C=O stretching vibration is attributed to ethyl acetate existing in different hydrophilic and hydrophobic environments. Specifically, the two low-wavenumber components arise from the formation of double and single hydrogen bonds between C=O and water or ethanol, respectively, while the high-wavenumber component is attributed to the interaction between C=O and the hydrophobic alkyl group. These findings suggest that the C=O stretching vibration of esters is sensitive to the surrounding hydrophilic and hydrophobic environments, thereby indicating its potential as a useful probe for identifying hydrophilic and hydrophobic interactions. Full article

In this study, a full multilevel factorial design (2¹ × 3¹ × 2¹) × 2 was conducted to investigate the effects of molar mass of chitosan (CS), the type of acid used for dissolution, and the composition of the coagulation bath on the coagulation, mechanical properties, and swelling of the filaments. The results showed the statistical significance of the factors in the characteristics of these filaments. The coagulation followed Fick’s second law of diffusion, with an increase in the chitosan molar mass reducing the coagulation rate, as did the use of acetic acid instead of lactic acid. CS with higher molar mass produced filaments with larger diameters, but without a proportional increase in tensile strength. Swelling was influenced by the acid and composition of the coagulation bath. The interaction of CS with acid and the CS molar mass factor were the terms of greatest statistical significance. Crystallinity was higher for samples dissolved in aqueous solutions of acetic acid and coagulated with ethanol, while lactic acid induced greater structural disorder. Samples coagulated with ethanol presented more homogeneous surfaces, while methanol resulted in rougher filaments. These findings emphasize the critical role of processing conditions in tailoring the properties of CS filaments, providing valuable insights for their optimization for biomedical applications. Full article

Photodynamic therapy (PDT) has garnered significant attention as an effective and safe method for cancer therapy, with ongoing efforts to develop new photosensitizers to enhance its efficacy. This study aimed to develop novel photosensitizers with aggregation-induced emission enhancement (AIEE) properties. A series of 3-phenyl pyrano[4,3-b]quinolizine compounds (3–10) were synthesized by reacting pyrones (1a–e) with 2-pyridylacetate (2a) or 2-pyridylacetonitrile (2b) and then evaluated for their potential as photosensitizers. Spectroscopic analyses revealed that all compounds emitted blue to green fluorescence in ethanol, with emission wavelengths ranging from 446 nm to 515 nm. Compounds 5 and 6, lacking a substituent at position 5 of pyrano[4,3-b]quinolizine, exhibited AIEE behavior in aqueous solution. Furthermore, all compounds produced reactive oxygen species upon exposure to LED light. Notably, compounds 5 and 6 demonstrate high singlet oxygen (¹O₂) generation efficiency in water-rich solvents, where they tend to aggregate, contributing to their potential to destroy cancer cells. In vitro studies using human colon cancer cells (Colo205) demonstrated that 5 and 6 exhibited potent anti-tumor activity upon exposure to LED light. These findings suggest that compounds 5 and 6, based on 3-phenyl pyrano[4,3-b]quinolizine, possessing AIEE properties, are potential new photosensitizers for PDT. Full article

Measuring surface soil moisture is vital for understanding water availability, agricultural productivity, and climate change impacts, as well as for drought prediction and water resource management. However, obtaining accurate data is challenging due to the lack of reliable probes that work across diverse soil types and conditions. This study evaluated a prototype dielectric probe developed by Daiki Rika Kogyo Co., Ltd., Saitama, Japan, through controlled laboratory experiments. The probe measures the real and imaginary parts of dielectric permittivity over 10–150 MHz in a 5.6 cm diameter, with a 2 cm length volume, achieving a ±2% accuracy for the real part of oil–ethanol and ethanol–water mixtures (3.26–79). The imaginary part of the dielectric permittivity of aqueous solutions is convertible into electrical conductivity (EC) with reasonable accuracy. For variably saturated sand, the real part is convertible to a volumetric soil-moisture content (≥0.10 m³m⁻³) using a custom equation. The probe’s variable-frequency measurements reduce the limitations of fixed-frequency approaches, accounting for the EC, clay, porosity, and organic matter effects. With its VNA principle and simultaneous measurement of dielectric properties, it offers innovative capabilities for addressing water management, agriculture, and climate prediction challenges. Full article

Strong-aroma type Baijiu and its diluted samples were characterized through descriptive analysis. Significant changes were observed in four (ethanol, Jiao-aroma, fruity, and grain) of the nine aroma attributes, primarily attributed to variations in ethanol concentration rather than other compounds. The thresholds of 40 compounds in aqueous solutions with alcohol concentrations of 20%, 30%, 40%, 50%, and 60% were measured using three-alternative forced-choice tests. The thresholds of 30 compounds were significantly positively correlated with ethanol concentration. The thresholds of 40 compounds were affected by ethanol concentration to varying degrees, with changes ranging from 2 to 692 times. Due to the varying degrees of alcohol influence on the compound threshold, the aroma profile of diluted Baijiu sample is different from the original Baijiu sample. Full article