Acid Esters Research Articles

Progress in the Study of Occurrence, Distribution, Material Flows, and Environmental Release of Substances of Very High Concern （SVHCs） in Plastics

Plastic additives provide plastics with excellent functions such as plasticizing, flame retardant, and antioxidant properties and are widely used in various plastics. Of these, 189 plastic additives have been included in the European Union's Candidate List of substances of very high concern （SVHCs） due to their potential environmental and health risks. These SVHCs are mainly used in PVC, PUR, and PE plastics and in the packaging, automotive, construction, electronic and electrical equipment, and textile sectors. Plasticizers and flame retardants are the most widely used and therefore the focus of SVHC risk assessment and risk management. Existing studies have carried out material flow analysis （MFA） for SVHCs in plastics, revealing the environmental and health risks of typical flame retardants and plasticizers throughout the product life cycle, such as polybrominated diphenyl ethers （PBDEs）, hexabromocyclododecane （HBCD）, and phthalic acid esters （PAEs）. A large amount of SVHCs enter waste streams at the end of the product life cycle, highlighting the importance of strengthening waste management for SVHCs risk management. In addition to the release of SVHCs from plastic products into the environment, plastic leakage is another important source of environmental release of SVHCs. Plastic debris that have been in the environment for a long time continue to release SVHCs and pose a long-term threat to the ecosystem and human health. In the future potentially hazardous chemicals must be crucially identified in different types of plastics and to assess their environmental release during their life cycle, in particular by establishing a database on hazardous chemicals in plastics and measuring emission factors, optimizing dynamic material flow analysis （d-MFA）, as well as studying the release mechanisms of hazardous chemicals from plastic leakage.

Sulphotransferase-mediated toxification of chemicals in mouse models: effect of knockout or humanisation of SULT genes.

Cytosolic sulphotransferase (SULT) enzymes catalyse reactions involved in xenobiotic elimination and hormone regulation. However, SULTs can also generate electrophilic reactive intermediates from certain substrates, including the activation of carcinogens. Here, we review toxicological studies of mouse strains with SULT status altered by genetic modification. Knockout mouse strains have been constructed for the enzymes Sult1a1, 1d1, 1e1, 2b1 and 4a1. In addition, transgenic strains are available for human SULT1A1/2. Among SULT knockout mouse strains, reduced fertility (Sult1e1) and early postnatal death (Sult4a1) were observed. In contrast, Sult1a1 or Sult1d1 knockouts and SULT1A1/2 transgenics were healthy and showed no obvious deficiencies. These strains were used in toxicological studies with 13 chemicals. Manipulation of the SULT system altered dramatically the adverse effects of many compounds; thus, very large differences in levels of DNA adducts formed in the liver or other tissues were seen with some chemicals - up to 99.2% decreases in knockouts and 83-fold increases in SULT1A1/2 transgenics. In many cases, these changes were restricted to the tissues in which the corresponding enzymes are expressed, arguing for local activation. However, with some compounds, the kidney was an important target tissue, due to the active transfer to that organ, via the circulation, of reactive sulphuric acid esters.

Pollution Status, Ecological Effects, and Bioremediation Strategies of Phthalic Acid Esters in Agricultural Ecosystems: A Review.

Phthalic acid esters (PAEs) are common organic contaminants in farmland soil throughout agricultural systems, posing significant threats to human health and thus closely associated with food safety concerns. Here, we consolidate the latest findings regarding the distribution, ecological effects, bioremediation methods, and microbial degradation pathways of PAEs in agricultural ecosystems. Generally, di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and di-isobutyl phthalate (DiBP) exhibit the highest detection frequencies and concentrations in soil, air and agricultural products. The presence of these PAEs in agricultural ecosystems can significantly affect soil and plant-associated microbial communities, leading to decreased yield and quality of agricultural products. Bioremediation techniques, such as microbial degradation and phytoremediation, are frequently explored to address these issues. Overall, this review provides a comprehensive overview of current research on PAEs in China's agricultural systems and offers insights into potential problems and future research directions.

Development of ZrO2-Coated SPME Fibers for Detecting Benzotriazole Ultraviolet Filters in Water Samples

In this study, the zirconium dioxide nanoparticles (ZrO2NPs) were coated on the surface of stainless steel (SS) by cyclic voltammetry (CV) as solid phase microextraction fiber coating for detection of the benzotriazole ultraviolet filters (BUvFs) in different real water samples. The composition and images of the new SS@ZrO2NPs fiber were characterized by scanning electron microscopy (SEM). The extraction capability of SS@ZrO2NPs fiber was investigated for the enrichment and detection of benzotriazole ultraviolet filters (BUvFs) phthalate acid esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) coupled with HPLC. The fabricated SS@ZrO2NPs fiber showed excellent extraction selectivity and good extraction capability for BUvFs. Under the optimized conditions, the SS@ZrO2NPs-SPME method presented linear ranging from 0.15 to 200 µg/L with correlation coefficients of higher than 0.9982. Moreover the limits of detection (LODs) varied from 0.020 µg/L to 0.138 µg/L. Relative standard deviations (RSDs) with single fiber were below 7.78% and 8.91% for intra-day and inter-day measurements, respectively. The developed method was used to the detection of trace BUvFs in different real water samples.

Sulfonic-acid-functionalized lignin-derived LC900@SO3H: A promising catalyst for the efficient production of biodiesel via the esterification of oleic acid

The renewable and clean biodiesel production makes higher demands for cheap, green and efficient catalysts. A sulfonic-acid-functionalized LC900@SO3H catalyst was prepared using alkali lignin as the carbon source, which was applied in the esterification of oleic acid to produce biodiesel. The yield of biodiesel reached 96.3% under mild conditions (Temperature = 95 ◦C, Catalyst dosage = 3.5wt%, MeOH/Oleic acid = 11.2:1, Time = 1.5h). The catalysts were reused at least 3 times with a high biodiesel yield of over 80%. The morphological and spectral analyses of the catalysts were conducted using BET, TGA, Raman, SEM, FTIR, and XPS, and the products were analyzed by GC and GC-MS. Characterizations indicated that the huge specific surface area (1618.68 m2/g) and large pore volume (0.8573 cm3/g) endow the LC900@SO3H with abundant sulfonic-acid-functionalized active sites for excellent catalytic activity. In addition, the response surface method (RSM) revealed the interaction of different reaction conditions for biodiesel production. The cost of 1kg catalyst was estimated as $3.59, showing good economic viabilities.

High-performance bio-based foam from agricultural waste luffa seed oil polyols

The present study aimed to develop eco-friendly polyurethane viscoelastic foam (PVF) with enhanced tear strength while preserving softness, comfort, and safety by utilizing bio-based polyols derived from luffa seed oil (LSO). Two types of bio-based polyols (PLSO-D and PLSO-M) were synthesized through the epoxidation process using diethylene glycol (DEG) and methanol (MeOH), respectively, for the production of LSO-based polyurethane viscoelastic foams (LSO-PVFs). The analyses revealed that these polyols exhibited high dispersion, appropriate hydroxyl values, and contained by-products such as oligomeric esters of fatty acids that facilitated physical and chemical crosslinking. LSO-PVFs demonstrated a uniform and fine cell structure with abundant open-cells, thick cell walls (55.5–76.6µm), and high apparent density (48.7–50.7kg/m3). Moreover, they exhibited enhanced tensile and tear strength (increasing up to 200% compared to petroleum-based PVFs), lower water absorption, excellent mildew resistance at 10% PLSO substitution. Additionally, these factors endowed LSO-PVFs with low indentation hardness and good bottom support performance, characterized by a compressive deflection coefficient of 2.30–3.54. This approach presents a sustainable alternative for foam production that offers comfort, durability while promoting the value-added utilization of agricultural waste.

Colorimetric and fluorimtric microenvironment responsivity of oxazolidine in solvatochromic latex nanoparticles: Versatile intelligent polymeric materials with advanced applications

Oxazolidine, a new category of stimuli-chromic dyes, has displayed a wide range of responsivities, such as halochromism, solvatochromism, ionochromism, and hydrochromism. The optical properties of oxazolidine molecules can be influenced notably by the polarity of solvent, media, and polymer nanoparticles. In this study, multi-functionalized acrylic latex nanoparticles containing different polar functional groups such as amide, amine, acid, hydroxyl, epoxide, and long-chain ester were synthesized by one-pot emulsion copolymerization. Prepared latex nanoparticles have a mean particle size in the range of 45–170 nm and spherical or non-spherical (anisotropic) morphologies depending on the polarity of functional groups. To prepare multi-color photoluminescent latex nanoparticles and investigation of solvatochromism in both colloidal solution and solid phase, as prepared multi-functionalized latex nanoparticles were modified physically with an oxazolidine derivative (5 wt%). Investigation of the solvatochromism of the oxazolidine in colloidal solution and solid phase indicated that the media is the main effective parameter for solvatochromism in colloidal solution. In the case of solid-state solvatochromism, the optical properties of oxazolidine were influenced significantly by the polarity of functional groups, because the interactions of oxazolidine molecules with functional groups of latex nanoparticles is the main parameter that influenced the solvatochromism. The solvatochromic properties of oxazolidine in solid polymer powders are useful for developing multi-color photoluminescent materials with advanced applications in the dual-mode visualization of latent fingerprints (LFPs), anticounterfeiting solid inks, and organic light-emitting diodes (OLEDs). Results displayed potential applications of multi-color polymer powders for the detection of LFPs under visible light and UV-light irradiation, for printing of optical security tags, and construction of OLEDs. The presented study introduces a new category of multi-color solid photoluminescent nanomaterials with multiple applications using solvatochromic properties.

Supersaturated drug delivery system of albendazole salt-polymer complex for improving oral bioavailability and efficacy anti-secondary E. multilocularis

Based on the supersaturation theory, this study devised two albendazole (ABZ) salt-polymer complexes that enhance the oral bioavailability and efficacy of secondary hepatic alveolar echinococcosis (HAE) in rats. Solid characteristics, microstructure, and stability of ABZ benzenesulfonate (ABZ-BSA) and ABZ methanesulfonate (ABZ-MSA) were evaluated. The equilibrium solubility and intrinsic dissolution rate of salt were measured across different pH environments to determine its potential for generating supersaturation. Polymer crystallization inhibitors were subsequently introduced to assess their impact on sustaining supersaturation. The pharmacokinetics and anti-echinococcosis effects of ABZ were evaluated in healthy SD and HAE rats. The characteristic peaks corresponding to amino acid esters and benzimidazole in the ABZ salt structure either shifted or disappeared, corroborated by PXRD, signifying successful ABZ salt preparation. Furthermore, reductions in the melting point and enthalpy of the salts were observed, along with discernible differences in microstructure compared to ABZ. The drug salts exhibited a significant increase in apparent solubility and intrinsic dissolution rate of ABZ, thus laying the groundwork for supersaturation. Stability assessments indicated that salts were susceptible to moisture absorption, necessitating stringent humidity control measures. Notably, HPMC-AS demonstrated promising capabilities in sustaining supersaturation. Finally, pharmacokinetic analyses revealed a substantial increase in the AUC of ABZ-BSA-H and ABZ-MSA-H by 7.6 and 20.3 times, respectively, compared to ABZ in vivo. After a 30-day once-daily oral administration of the Salts and ABZ to SD rats with hepatic alveolar echinococcosis, the ABZ-BSA-H and ABZ-MSA-H formulation demonstrated a cysts inhibition effect 9.2-fold and 15.3-fold greater than that of ABZ. The salt-HPMC-AS complex could potentially be developed into an improved anti-AE drug therapy. Therefore, the salt-HPMC-AS complex could be developed into an enhanced anti-AE drug therapy.

Evaluation of phthalate acid esters (PAEs) in kefir samples by using magnetic chitosan coated with polyaniline (Fe3O4@CHI@PANI)/GC–MS method: A health risk assessment study

In this study, by magnetic chitosan coated with polyaniline (Fe3O4@CHI@PANI) −gas chromatography/mass spectrometry (GC/MS) method was applied to analyze six PAE compounds in kefir samples. The results obtained from kefir samples showed that the lowest and highest mean of PAEs were associated to dimethyl phthalate (DMP was not detected or nd) and di-n-octyl phthalate (DNOP, 2.12 µg/kg), respectively. Also according to results the average of DEHP (Bis(2-ethylhexyl)phthalate) and total PAEs in all samples were 1.31 ± 0.72 and 4.58 ± 1.87 µg/kg, respectively. Furthermore, maximum and minimum mean of total PAEs were detected in the packages with a volume of 1000 mL (5.47 ± 2.03 μg/kg) and packages with a volume of 1500 mL (3.69 ± 1.23 μg/kg), respectively, and the maximum and minimum mean total PAE (μg/kg) were related to samples with a date less than the expiration date (5.42 ± 1.46) and samples with a date greater than the production date (3.73 ± 1.91), respectively. The level of these contaminants was lower than the existing standard levels. The assessment of human health risks, comprising risks of non-carcinogenic and carcinogenic were calculated with Monte Carlo simulation (MCS) and sensitivity analysis under certain removal efficiencies from 5 to 95 %. The result of the carcinogenic risk for DEHP showed that adults are not threatened by the consumption of kefir (1.06E-05), while children are exposed to negligible risk the consumption of kefir (1/48E-04). In all samples, the total non-carcinogenic risk of PAE compounds was less than 1 (TTHQ was 2.03E-04 and 4.33E-05 for children and adults, respectively), this values presenting there would be unlikely risks of non-carcinogenic of PAEs in kefir for consumers. In conclusion, it can be stated it doesn’t pose any threat to Iranian consumers (adults and children).

Occurrence, bioaccumulation, and partitioning of phthalate acid esters in the third largest freshwater lake (Lake Taihu) in China

Phthalate acid esters (PAEs) are a category of plasticizers that are ubiquitous in freshwater environments attributable to extensive utilization. We collected water, suspended particulate matter (SPM), surface sediments, phytoplankton, and zooplankton from 23 sampling sites to investigate and complement the occurrence, bioaccumulation, and partitioning of five PAEs including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), and di (2-ethylhexyl) phthalate (DEHP) in the third largest freshwater lake (Lake Taihu) of China. PAEs were extracted using Soxhlet extraction and solid phase extraction, and determined by gas chromatography-mass spectrometry. The average concentrations of the five PAEs in the water column, SPM, sediments, phytoplankton, and zooplankton of Lake Taihu were 1.93±1.57μgL-1, 765±766μgg-1, 1.68±1.47μgg-1, 1358±1877μgg-1, and 72.7±134μgg-1, respectively. DBP and DEHP were the dominant PAE congeners in the five environment compartments. The logarithmic concentrations of DBP, BBP, and DEHP in the SPM were negatively correlated with the logarithmic content of the SPM. Biodilution significantly impacted the occurrence of PAEs in the plankton. Bioaccumulation of PAEs was found in the plankton with log BCF (bioconcentration factor) in the phytoplankton ranging from 1.78±0.86 to 4.13±1.23 and log BAF (bioaccumulation factor) in the zooplankton varying from -0.10±0.26 to 3.04±0.64. Biomagnification of the PAEs from phytoplankton to zooplankton was not observed. DMP, DEP, and BBP migrated from sediments to water. DBP was in dynamic equilibrium in the sediment-water system. DEHP transferred from water to sediments. Our results provide crucial complementary knowledge on bioaccumulation and transfer of PAEs in planktonic food web, and their partitioning in different compartments of waters.

Anti-ulcerogenic activity of Citrus medica var. sarcodactylis fruit extract nano-emulsion in gastric ulcer rat model through modulating HMBG1/TLR4/NF-κB and Nrf2/HSP70/PGE2 signaling pathways

One of the most prevalent gastrointestinal multi-etiological diseases is gastric ulcer, with several consequences and serious side influences. Nowadays, nanotechnology is one of the advanced tools to enhance drug delivery and bioavailability. Hence, the prime goal of this study was to create safe gastro-protective therapy using methanol fruit extract of Citrus medica var. sarcodactylis (CMF) and its prepared nano formula (Nano-CMF). CMF or its nano form was given to rats at dose 600 mg/kg/day for a week along with a single oral administration of ethanol (5 ml/kg) at the 7th day. The particle size distribution of formulated CMF reflected the successful preparation of nano form, with average size 65 nm. Pretreatment with CMF or its nano formula to ethanol challenged rats significantly controlled the inflammatory response through down-regulated gastric HMBG1/TLR4/NF-κB signaling pathway and its downstream mediators at p<0.001. Moreover, CMF or nano-CMF lessened oxidative stress incidence via modulating Nrf2 signaling pathway, sustaining prostaglandin content, and reducing gastric juice acidity with a significant p value less than 0.001, as compared to the EtOH-intoxicated rats. In addition, nano form effectively preserved the gastric mucosal integrity and alleviated apoptosis in gastric cells as validated by ulcer index (p<0.001), and the histological and immunohistochemical findings, when matched to the EtOH-treated group. The metabolomics analysis revealed the characterization of 36 compounds. GC/MS of CH2Cl2 fraction led to the identification of 34 compounds, the major category was fatty acid esters amounting 43.92%. The TLC technique for methanol extract led to isolation of 8 compounds: (4,5-O-Dicaffeoylquinic acid, ferulic acid, hesperidin, limettin, 5-demethylsinensetin, brassicasterol, campesterol and β-sitosterol). Brassicasterol is newly reported from species while 5-demethylsinensetin was newly reported from the Citrus genus. Furthermore, the docking experiments revealed strong binding affinity interactions of these compounds with TLR-4, Nrf2-Keap1 complex, and pNF-κBp65. In conclusion, mechanism of action of CMF or its nano formula exerting anti-ulcer effect was postulated based on the synergistic action of its reported compounds which possesses anti-inflammatory, antioxidant, and anti-apoptotic activities. To be noted, nano CMF showed a superior potent anti-ulcer activity than CMF and conventional therapy, omeprazole.

Catalytic properties of selenium and phosphorus ionic liquids heterogenized on algae-based biochar

Catalytic performance of pyridinium hydrogen selenate (PHSe) and pyridinium dihydrogen phosphate (PH2P) ionic liquids immobilized on algae-based biochar (AC) was studied for the first time. For that purpose, acetic acid esterification with butanol was used as a test reaction. To investigate the surface effects, textural properties and thermal behavior for PHSe/AC and PH2P/AC, physicochemical methods such as X-ray powder diffraction (XRD), nitrogen adsorption–desorption isotherms (SBET) scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were applied. In addition, influence of the catalyst content (5–12 wt%) and reaction temperature (60–80 °C) on the butyl acetate yield and rate constant of esterification were evaluated. SBET and SEM measurements revealed that all of the samples (AC, PHSe/AC and PH2P/AC) obtained are mixed microporous-mesoporous materials. XRD and XPS data showed more highly dispersed PH2P particles than PHSe on the carrier surface due to stronger surface ionic liquid-support interaction for PH2P/AC in comparison with PHSe/AC. The latter was responsible for higher thermal stability of PH2P/AC with respect to PHSe/AC. In addition, more obvious PH2P sites (than PHSe) on the biochar surface favored the ester production in the presence of PH2P/AC (77.4 % and 53.26 × 10−4 l/mol × min) more evidently than PHSe/AC (58.1 % and 28.82 × 10−4 l/mol × min).

Rapid HCFC-141b hydrate formation and high-density cold storage in the presence of acid ester surfactants

To improve HCFC-141b hydrate production, eco-friendly nonionic surfactants were used as promoters to enhance hydrate formation. Stearic acid polyoxyethylene ester (SG) effectively improve HCFC-141b hydrate formation, and the promotion effect is influenced by the hydrophilicity and mass fraction of surfactant. Ethylene oxide (EO) numbers of SG series surfactants affect on hydrate nucleation induction time and cold storage density. Surfactants with appropriate HLB values have better promotion effects. Hydrate has shorter induction times and higher cold storage density with SG-20. When the concentration of SG-20 is 1 %, the induction time reduces to 36 min, and the cold storage density is up to 245.1 kJ/kg, which is the optimal addition amount for HCFC-141b hydrate production. Comparing the three systems, the HCFC-141b hydrate system with 1 wt% SG-20 has the best cycling stability.

The Effect of Dicarboxylic Acid Structure on the Plasticizing Ability of Its Ester

Polyvinyl chloride (PVC) belongs to the most widely used group of thermoplastics. Most of the market for PVC products belongs to plasticized compositions. Plasticizers are the most demanded additives in the polymer industry. Environmental problems and the identified toxicity of the plasticizer di(2-ethylhexyl) phthalate (DEHP) stimulate the restriction of its use and contribute to the development of alternative plasticizers. As a possible replacement for phthalates, esters of dicarboxylic acids are known to provide reduced toxicity and high frost resistance to the resulting compositions. In this regard, esters of dicarboxylic acids and ethoxylated alcohols were obtained and their compatibility with polyvinyl chloride was investigated. The plasticizing effect of the esters obtained was evaluated. The thermomechanical characteristics of PVC compositions containing the developed plasticizers were studied, the glass transition temperature was determined, and the areas of the glassy and highly elastic state of the plastics were identified. It was shown that the chemical structure of dicarboxylate used as a plasticizer determines the important technological and operational characteristics of the PVC plastics obtained. Dibutoxyethyl sebacate (DBES) has the best plasticizing effect among the synthesized esters. The expansion of the highly elastic state area for PVC samples containing this ester exceeded the industrial plasticizers DEHP and di(2-ethylhexyl) adipate (DOA). The indicators of the critical temperature of dissolution of PVC in the esters under study suggest ensuring their low migration from PVC plastics.

Hierarchical micro-meso-macroporous xAIL@HP UIO-66-NH2 catalysts used for efficient biodiesel production from low-grade acidic oils

The utilization of hierarchical porous supports to fabricate an efficient solid catalyst is a feasible strategy due to their remarkable merit in ameliorating the diffusion of reactants on the catalyst surface and increasing the exposure of active species in particular for the bulky molecule-involving reactions. In this research, to abatement the mass transfer resistance of large triglycerides, the hierarchical porous solid catalyst (xAIL@HP UIO-66-NH2) was prepared by grafting acidic ionic liquid (AIL) with double acidic sites of -SO3H and HSO4- onto micro-meso-macroporous metal-organic gels (HP UIO-66-NH2) through acid-base interactions between -NH2 moiety of HP UIO-66-NH2 and acidic moiety of AILs. The catalyst characterization results showed that the xAIL@HP UIO-66-NH2 catalyst owned the hierarchical porous structure and double Brønsted-Lewis acid centers with large BET surface area and pore volume. This catalyst was adopted for efficient biodiesel production from low-grade acidic oils, exhibiting high catalytic activities for triglyceride transesterification and free fatty acid (FFA) esterification reactions. By using acidic oils as feedstocks, the oil transesterification conversion could reach 91.3 % and the FFAs were completely converted to biodiesel under the conditions of 130 °C for 8 h at methanol-to-oil molar ratio of 35: 1 and catalyst dosage of 8 wt%. Based on the kinetic study, the activation energy Ea of this catalyst was 56.6 kJ/ mol, and the reaction complied with pseudo-first-order kinetics. This solid catalyst demonstrated satisfactory acid and water resistance, with good reusable performance, posing great potential in the efficient biodiesel preparation by the one-pot method using the low-grade acidic oils.

Producing and Testing the Properties of Biodiesel Sourced from Hemp Oil

Organic matter is converted into a variety of fuels, including potential replacements for transport fuels. New sources of raw materials are being sought for their acquisition. One such raw material that is currently attracting a growing degree of attention is hemp. The objective of this study was to produce biodiesel from hemp oil to ascertain its selected properties and to compare them with the properties of biodiesel obtained from rapeseed oil and the properties of diesel fuel. A reactor designed for the non-industrial, local conversion of available raw materials into fatty acid esters was used for the manufacture of biodiesel. The properties of hemp oil biodiesel were evaluated in comparison with those of rapeseed oil biodiesel, with properties of diesel fuel, and with the requirements set forth in the EN 14214 standard, pertaining to the specification of fatty acid methyl esters for utilization in compression-ignition internal combustion engines. The kinematic viscosity value of the hemp oil biodiesel yielded just below the upper limit defined in the standard. Furthermore, research has demonstrated that such biodiesel contains a considerable proportion of esters of linoleic and linolenic acids, which are susceptible to oxidation. The content of linolenic acid ester in esters produced from hemp oil is clearly higher than the content of this ester in esters obtained from rapeseed oil. This higher content contributes to the high value of the iodine number, significantly exceeding the standard requirements. The remaining designated properties of hemp oil biodiesel are in accordance with the requirements laid down in the standard and exhibit similarities to those of rapeseed oil biodiesel. Further research is recommended to enhance the characteristics of hemp oil biodiesel and its utilization in compression-ignition engines.

Rosmarinic Acid Ameliorates Dermatophagoides farinae Extract-Induced Atopic Dermatitis-like Skin Inflammation by Activating the Nrf2/HO-1 Signaling Pathway

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases. AD pathogenesis is associated with increased oxidative stress, impairment of the skin barrier, and activation of the immune response. Rosmarinic acid (RA), a caffeic acid ester, is known for its anti-inflammatory and antioxidant properties. However, the effects of RA on Dermatophagoides farinae extract (DfE)-induced AD-like skin inflammation, as well as its ability to regulate oxidative stress through the Nrf2/HO-1 pathway in TNF-α/IFN-γ-treated keratinocytes, remain unclear. We investigated RA activity in a DfE-induced AD-like skin inflammation mouse model and IFN-γ/TNF-α-stimulated keratinocytes. We found that RA attenuates DfE-induced inflammation by decreasing dermatitis scores and serum inflammatory marker levels and mast cell infiltration. Additionally, RA significantly suppressed IFN-γ/TNF-α-induced chemokine production in keratinocytes and reduced Th cytokine levels in concanavalin A-stimulated splenocytes. Importantly, RA also increased Nrf2/HO-1 expression in TNF-α/IFN-γ-treated keratinocytes. In conclusion, this study demonstrated that RA effectively alleviates DfE-induced AD-like skin lesions by reducing the levels of inflammatory cytokines and chemokines. Furthermore, RA promotes Nrf2/HO-1 signaling in keratinocytes, which may help mitigate DfE-induced oxidative stress, thereby alleviating AD-like skin inflammation. These findings highlight the potential of RA as a therapeutic agent for treating AD and other skin inflammation.

The Effect of the Structure of the Alcohol Component on the Plasticizing Ability of the Ester of Aliphatic Dicarboxylic Acid

Esters of aliphatic dicarboxylic acids are promising plasticizers of polyvinyl chloride due to their low toxicity and high biodegradability. Plasticized PVC materials containing them are characterized by high frost resistance and heat resistance. In this regard, esters of adipic acid and alkoxylated alcohols with various structures have been obtained. The influence of alcohol structure on the plasticizing ability of ether has been determined. A theoretical assessment of the plasticizing effect of diesters in relation to PVC was performed based on the calculation of Hansen solubility parameters. For this purpose, the thermodynamic compatibility of adipates with PVC was investigated. The processability of esters in the composition of PVC compositions was studied according to the values of the critical temperature of dissolution of PVC. The intervals of transition of plastics from a glassy to a highly elastic state, as well as the depression of the glass transition temperature of compounds containing adipates, were determined. Rheological characteristics of PVC compositions based on the obtained adipates were investigated. It is shown that the chemical structure of the alcohol group determines the important technological and operational characteristics of esters in the composition of polymer materials.

Enhanced Biodiesel Production with Eversa Transform 2.0 Lipase on Magnetic Nanoparticles.

This research investigated the usefulness of magnetic iron oxide nanoparticles (Fe3O4) as a support to immobilize the lipase Eversa Transform 2.0 (ET 2.0) to obtain an active and stable biocatalyst, easily recoverable from the reaction medium for applications in the production of biodiesel. Biodiesel was an alternative fuel composed mainly of fatty acid esters with strong transesterification and esterification capabilities. The study focused on the esterification of oleic acid with ethanol to synthesize ethyl oleate. Magnetic nanoparticles were prepared by coprecipitation, then activated with glutaraldehyde and functionalized with γ-aminopropyltriethoxysilane (APTES). The optimal conditions for immobilizing ET 2.0 were pH 10, 25 mM sodium carbonate buffer, an enzymatic load of 200 U/g, and 1 h of contact time, obtaining 78% yield and enzymatic activity of 205.9 U/g. Postimmobilization evaluation showed that the immobilized enzyme performed better than its free form. Kinetic studies were conducted under these optimized conditions (2-96 h at 150 rpm and 37 °C). The biocatalyst was tested for the synthesis of ethyl oleate using oleic acid as the substrate and ethanol, achieving a conversion of 88.1%. Subsequent recirculation tests maintained approximately 80% conversion until the fourth cycle, confirming the sustainability of ester production. Molecular docking studies revealed that the binding affinity for the enzyme-docked oil composition was estimated at -5.8 kcal/mol, suggesting that the combination of the substrate and lipase was stable and suitable for esterification.

Stimuli-Responsive Photoluminescent Molecular Tweezers for Highly Enantioselective Discrimination of Chiral Primary Amines.

To address the challenge of chiral recognition in terms of efficiency and generality, we propose a novel fluorescence sensing approach by rationally designing metal-ion-responsive chiral molecular tweezers. The flexible and adaptable molecular tweezers enable facile recognition of 31 structurally varied chiral primary amine compounds, including amino acids, amino acid esters, and chiral amines. Notably, upon stimulation by zinc ions, the chiral molecular tweezers demonstrate a higher enantioselective fluorescence response. Combined density functional theory calculations reveal that the chiral sensing mechanism relies on differential reaction rates and potential hydrogen-bonding interactions between the two enantiomers and the chiral receptor, which results in one of the enantiomers forming a more abundant, stable, and structurally rigid complex with the receptor, resulting in a significant increase in the fluorescence intensity and enantioselectivity. The stimuli-responsive molecular tweezers approach provides a novel strategy for precise stereocontrol and universality of chiral recognition, offering a promising tool for applications in various fields.