Acid Mixture Research Articles

Interfacial Enrichment of Lauric Acid Assisted by Long-Chain Fatty Acids, Acidity and Salinity at Sea Spray Aerosol Surfaces.

Surfactant monolayers at sea spray aerosol (SSA) surfaces regulate various atmospheric processes including gas transfer, cloud interactions, and radiative properties. Most experimental studies of SSA employ a simplified surfactant mixture of long-chain fatty acids (LCFAs) as a proxy for the sea surface microlayer or SSA surface. However, medium-chain fatty acids (MCFAs) make up nearly 30% of the FA fraction in nascent SSA. Given that LCFA monolayers are easily disrupted upon the introduction of chemical heterogeneity (such as mixed chain lengths), simple FA proxies are unlikely to represent realistic SSA interfaces. Integrating experimental and computational techniques, we characterize the impact that partially soluble MCFAs have on the properties of atmospherically relevant LCFA mixtures. We explore the extent to which the MCFA lauric acid (LA) is surface stabilized by varying acidity, salinity, and monolayer composition. We also discuss the impacts of pH on LCFA-assisted LA retention, where the presence of LCFAs may shift the surface-adsorption equilibria of laurate─the conjugate base─toward higher surface activities. Molecular dynamic simulations suggest a mechanism for the enhanced surface retention of laurate. We conclude that increased FA heterogeneity at SSA surfaces promotes surface activity of soluble FA species, altering monolayer phase behavior and impacting climate-relevant atmospheric processes.

An Integrated Module Performs Selective ‘On‐Line’ Epoxidation in the Biosynthesis of the Antibiotic Mupirocin.

The delineation of the complex biosynthesis of the potent antibiotic mupirocin, which consists of a mixture of pseudomonic acids (PAs) isolated from Pseudomonas fluorescens NCIMB 10586, presents significant challenges and the timing and mechanisms of several key transformations remain elusive. Particularly intriguing are the steps that process the linear backbone from the initial polyketide assembly phase to generate the first cyclic intermediate PA‐B. These include epoxidation as well as incorporation of the tetrahydropyran (THP) ring and fatty acid sidechain required for biological activity. Here, we show that the mini‐module MmpE performs a rare online (ACP‐substrate) epoxidation and is integrated (‘in‐cis’) into the polyketide synthase via a docking domain. A linear polyketide fragment with 6 asymmetric centres was synthesised using a convergent approach and used to demonstrate substrate flux via an atypical KS0 and a previously unannotated ACP (MmpE_ACP). MmpE_ACP‐bound synthetic substrates were critical in demonstrating successful epoxidation in vitro by the purified MmpE oxidoreductase domain. Alongside feeding studies, these results confirm the timing as well as chain length dependence of this selective epoxidation. These mechanistic studies pinpoint the location and nature of the polyketide substrate prior to the key formation of the THP ring and esterification that generate PA‐B.

Electrochemical Synthesis of Isoquinoline Sulfone Compounds and Study of their Inhibition of Acetolactate Synthase Enzyme Activity

AbstractBoth of sulfone compounds and isoqunoline derivatives are important compounds. In this paper, Isoquinoline C1 and C3 Sulfone compounds have been synthesized by electrochemical means using isoquinoline N‐Oxides and some sodium benzenesulfinate as reactants, inexpensive and easily available sodium iodide as electrolytes, and a mixture of acetonitrile, water and acetic acid as reaction solvents. By using the method, a series of isoquinoline sulfone compounds have been synthesized in high yields. The reaction does not need oxidants and catalysts, and the reaction conditions are mild, environmentally friendly, efficient and suitable. In addition, we also carried out ALS enzyme inhibition experiments on the synthesized isoquinoline sulfone compounds, six of the isoquinoline sulfone compounds synthesized herein were found to inhibit ALS enzyme at a high rate, four of them inhibited ALS enzyme at a rate comparable to that of the commercialized herbicides Halosulfuron and Broadstrike, and the other two compounds also inhibited ALS enzyme at a rate higher than that of Halosulfuron and Broadstrike. Therefore, it is possible to find lead compounds with good herbicidal activity potential from these 6 compounds.

Supraperiosteal technique protocol for forehead filling with a mixture of calcium hydroxyapatite and hyaluronic acid: Double-blind, randomized controlled clinical trial.

The current study aims to investigate the safety and efficacy of using calcium hydroxyapatite (CaHA) versus CaHA associated with hyaluronic acid (HA) for forehead volume replacement and contour restoration without forehead irregularities. This interventional study involved 132 participants in a two-arm, parallel, double-blind trial for forehead treatment using the supraperiosteal technique. Group A received CaHA, and Group B received a combination of CaHA and HA as filler materials. Follow-up assessments occurred at 30 and 180 days, incorporating the 5-point Global Aesthetic Improvement Scale (GAIS) and photographic analysis for forehead volume replacement, contour restoration, and without forehead irregularities. Safety assessments included monitoring adverse events, particularly nodules. The study included all 132 enrolled patients who completed the trial. Applying CaHA in combination with HA resulted in a statistically significant improvement in both GAIS scale scores and the reduction of forehead irregularities. The total incidence of nodules was 3.7%. Group A had four times more occurrences of nodules than Group B. Furthermore, Group B exhibited lower rates of forehead irregularities following the treatment compared to Group A. The supraperiosteal application of CaHA and HA for forehead treatment demonstrates superior efficacy in addressing signs of aging compared to the isolated use of CaHA.

The Antioxidant and HDAC-Inhibitor α-Lipoic Acid Is Synergistic with Exemestane in Estrogen Receptor-Positive Breast Cancer Cells.

Anti-estrogenic therapy is established in the management of estrogen receptor (ER)-positive breast cancer. However, to overcome resistance and improve therapeutic outcome, novel strategies are needed such as targeting widely recognized aberrant epigenetics. The study aims to investigate the combination of the aromatase inhibitor exemestane and the histone deacetylase (HDAC) inhibitor and antioxidant α-lipoic acid in ER-positive breast cancer cells. First, the enantiomers and the racemic mixture of α-lipoic acid, and rac-dihydro-lipoic acid were investigated for HDAC inhibition. We found HDAC inhibitory activity in the 1-3-digit micromolar range with a preference for HDAC6. Rac-dihydro-lipoic acid is slightly more potent than rac-α-lipoic acid. The antiproliferative IC50 value of α-lipoic acid is in the 3-digit micromolar range. Notably, the combination of exemestane and α-lipoic acid resulted in synergistic behavior under various incubation times (24 h to 10 d) and readouts (MTT, live-cell fluorescence microscopy, caspase activation) analyzed by the Chou-Talalay method. α-lipoic acid increases mitochondrial fusion and the expression of apoptosis-related proteins p21, APAF-1, BIM, FOXO1, and decreases expression of anti-apoptotic proteins survivin, BCL-2, and c-myc. In conclusion, combining exemestane with α-lipoic acid is a promising novel treatment option for ER-positive breast cancer.

Formic and lactic acids from the conversion of xylose with the use of modified clinoptilolite by sonication

AbstractBACKGROUNDA material of natural origin, clinoptilolite, was modified with selected metals in order to obtain a catalyst for the conversion of xylose – the main component of the hemicellulose fraction present in lignocellulosic biomass – to selected carboxylic acids.RESULTSThe starting material without modification (0‐parent), the hydrogen form (0‐hydrogen) of zeolite and zeolite after hierarchization with hydrochloric acid (0‐dealuminated) were used. Iron, copper and cobalt ions were introduced as active centers using the sonication technique. The catalytic process was carried out in a pressure autoclave for 2 h at a temperature of 220 °C. Compounds such as formic acid with a yield of 91% (0‐parent) and lactic acid with a yield of 66.1% (Fe‐hydrogen) were obtained.ConclusionThe catalytic processes carried out using xylose lead to the obtaining of a mixture of carboxylic acids: lactic acid, pyruvic acid and formic acid. An important role here is played by the presence of iron as an active site, which leads to the transformation of xylose into lactic acid by dehydration, and the presence of Lewis and Brønsted active sites. In the case of formic acid, which has never been reported in publications on a similar topic, the starting zeolite without modification contributed to its preparation. It is possible that the content of alkali metals contributed to its preparation along with the coupling of the oxidation reaction of the intermediate product, because of the presence of small amounts of iron, which are present in the natural material. © 2024 Society of Chemical Industry (SCI).

Influence of bulk-phase acidity, organic fraction, and dissolved oxygen on the photosensitized renoxification of nitrate in NaNO3/humic acid mixtures

Nitrate renoxification significantly influences atmospheric nitrogen cycling and global OH budgets. Although numerous nitrite acid (HONO) formation pathways from nitrate photolysis have been widely reported, the influence of various environmental factors and aerosol properties on reactive nitrogen production remains largely unclear. In this work, we employed NaNO3/humic acid (HA) as a model nitrate photosensitization system to investigate the crucial roles of aerosol acidity, organic fraction, and dissolved oxygen in the production of HONO, NO2, and NO2-. The presence of HA at 10 mg/L resulted in a remarkable increase in HONO production rates by approximately 2–3 times and NO2- concentration by 3–6 times across a pH range of 5.2 to 2.0. Meanwhile, the molar fraction of gaseous HONO in total N(III) production increased from 4 % to 69 % as bulk-phase pH decreased from 5.2 to 2.0. The higher organic fraction (i.e., 20 and 50 mg/L HA concentration) instead inhibited HONO and NO2 release. The presence of dissolved oxygen was found to be adverse for reactive nitrogen production. This suggests that the HA photosensitizer promoted the secondary conversion of NO2 to HONO mainly via reduced ketyl radical intermediates, while superoxide radical formation might exert a negative effect. Our findings provide comprehensive insights into reactive nitrogen production from photosensitized nitrate photolysis mediated by various external and internal factors, potentially accounting for discrepancies between field observations and model simulations.

Enhanced lithium host performance of multi-walled carbon nanotubes through acidic functionalization for lithium–sulfur batteries

Carbon nanotubes (CNTs) have been explored as a potential cathode material for lithium-sulfur (Li–S) batteries owing to their unique structure. However, traditional CNTs exhibit poor dispersion properties when preparing electrodes. The non-uniform distribution of the conductive agents hinders the formation of enough sites for sulfur loading, which results in the aggregation of sulfur/Li2S and severe polarization. In this study, we propose the acidic functionalization of CNTs in the cathode structure as a practical solution for mitigating the poor dispersion and polysulfide shuttling in lithium-sulfur batteries. Multiwalled CNTs were functionalized by oxidation through acidic treatment using sulfuric, nitric, and mixed acids. The cathode prepared with a mixture of sulfuric and nitric acids showed a coulombic efficiency of 99 % after 100 cycles, with a discharge capacity of 743 mAh g−1. These findings demonstrate the effectiveness of the acidic functionalization of CNTs as a promising approach for enhancing the electrochemical performance and commercial viability of lithium-sulfur batteries.

Impact of omega-3 fatty acids on hypertriglyceridemia, lipidomics, and gut microbiome in patients with type 2 diabetes.

Fish oil (FO), a mixture of omega-3 fatty acids mainly comprising docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been recommended for patients with type 2 diabetes (T2D) and hypertriglyceridemia. However, its effects on lipidomic profiles and gut microbiota and the factors influencing triglyceride (TG) reduction remain unclear. We conducted a 12-week, randomized, double-blind, placebo-controlled trial in 309 Chinese patients with T2D with hypertriglyceridemia (ClinicalTrials.gov: NCT03120299). Participants were randomly assigned (1:1) to receive either 4g FO or corn oil for 12weeks. The primary outcome was changes in serum TGs and the lipidomic profile, and the secondary outcome included changes in the gut microbiome and other metabolic variables. The FO group had significantly better TG reduction (mean [95% confidence interval (CI)]: -1.51 [-2.01, -1.01] mmol/L) compared to the corn oil group (-0.66 [-1.15, -0.16] mmol/L, p= 0.02). FO significantly altered the serum lipid profile by reducing low-unsaturated TG species and increasing those containing DHA or EPA. FO had minor effects on gut microbiota, while baseline microbial features predicted the TG response to FO better than phenotypic or lipidomic features, potentially mediated by specific lipid metabolites. A total of 9 lipid metabolites significantly mediated the link between 4 baseline microbial variables and the TG response to FO supplementation. Our findings demonstrate differential impacts of omega-3 fatty acids on lipidomic and microbial profiles in T2D and highlight the importance of baseline gut microbiota characteristics in predicting the TG-lowering efficacy of FO. This study was funded by the National Nature Science Foundation.

Bidentate pyridine-pyrazole ligand-induced synergistic and antagonistic effects for selective separation of nickel from sulfuric acid medium

Short-process hydrometallurgy is promising for non-traditional resource utilization due to low cost and less consumption, but it presents a great challenge to metal separation of complex leaching solutions. Herein, a bidentate pyridine-pyrazole ligand (BPP) was synthesized to realize the direct extraction of nickel from sulfuric acid leachate of laterite ore. The separation behaviors of nickel over other impurities (Co, Mn, Mg, Al, Ca, Fe, and Zn) were evaluated for the mixtures of BPP and dinonyl naphthalenesulfonic acid (DNNS). This binary system exhibits the synergistic effect on nickel and antagonistic effect on impurities, which improves the selective separation of nickel. The molar ratio of BPP/DNNS, solution pH, extractant concentration, and nickel concentration on metal extraction were investigated. The extraction efficiency of nickel reaches 95.9 % at pH = 2.5, and the separation coefficients of nickel over aluminum, manganese, and iron is 86.2, 95.4, and 69.4 at the optimal DNNS/BPP molar ratio of 1:1, respectively. Furthermore, the component interaction and coordination structure were disclosed through NMR, ATR-IR, XAS, and UV–vis spectroscopies. The mechanism analysis indicated that the exclusion of coordinated water molecules with BPP contributes to the synergistic extraction of nickel, and the intermolecular interaction between DNNS and BPP inhibits the extraction of impurities. Therefore, the pyridine-pyrazole ligand-induced synergistic and antagonistic effects will be helpful to the short process utilization of complex nickel-bearing resources.

Effect of graphite oxide on the mechanical, thermal, structural and hydrophilicity proprieties of Polypropylene / Poly(Propylene-Glycol) Acrylate / Glycidyl Methacrylate PP/PPGA/GMA composite

This research aims to investigate the synergistic effects of grafting flexible fractions and incorporating reinforcing fillers in polypropylene (PP) matrix. The primary objective is to establish an experimental methodology for preparing and characterizing Polypropylene / Poly(Propylene-Glycol) Acrylate / Glycidyl Methacrylate (PP/PPGA/GMA) composites loaded with graphite oxide (GtO).The process of oxidizing natural graphite powder using a mixture of sulfuric acid and nitric acid was validated through various analytical techniques including IRTF, AFM, DRX, XRF and ATG. The grafting reaction of PPGA and GMA on polypropylene and the incorporation of graphite oxide with varying levels were carried out in the melt state in a Brabender internal mixer; Dicumyl peroxide (DCP) was used as a radical initiator. A comprehensive assessment of the obtained materials was conducted through conventional analyses encompassing mechanical properties (tensile and impact), thermal behaviors (ATG and DSC), morphological characteristics (SEM) and the chemical state of film surfaces (Contact angle).The investigation revealed two key outcomes. Firstly, it showcased the grafting effect of PP on the polymer's morphology and properties. Secondly, it underscored the consequential impact of incorporating graphite oxide on the overall behavior of produced materials.

The effect of wood particles polyesterification with sorbitol and citric acid on the properties of particleboard produced with the use of PF/pMDI adhesive

AbstractThis study investigated the effect of pine particle polyesterification with the mixture of sorbitol and citric acid (SCA) on the properties of particleboard bonded with the PF/pMDI hybrid resin. The use of SCA with a concentration of 35% contributed to improvement in the internal bond of the particleboards, their water resistance and dimensional stability. However, lowering the concentration to 25% resulted in a deterioration of the properties of produced materials. The effect of different loadings of pMDI in the PF/pMDI resin (0%, 5%, 15%, 25%) was also investigated and the outcomes showed a positive effect of the share of 15% and 25%. Furthermore, boards made of treated particles were characterized by slightly better flammable properties (lower mass loss, flashing point temperature and delayed ignition), and the visibility of the effect increased with the increase in the concentration of the impregnate. The results also indicate that the introduction of pMDI may also influence the ignition of the board.

A Short Review: The Use and Application of Matrix Resins Formed with Some Plant-Based Oils in Bio-Composite Materials

Increasing environmental problems, waste recycling problems, and non-biodegradable resources have led researchers to different searches for composite materials in recent years. In these studies, interest in bio-composite materials known as green composites has increased significantly due to their potential to replace traditional materials in material production. The creation of biocomposite materials from natural fibers or natural resins instead of synthetic fibers and synthetic resins has made natural resources the focus of researchers. Among these natural resin formations, the use of vegetable-based oils in various applications has started to be seen frequently due to their low cost, biodegradability, and availability. In addition to being recyclable, vegetable-based oils are an important alternative in many sectors, especially in the chemical industry, both environmentally and economically, with a wide variety of chemical conversion possibilities. The desire to explore the versatility of vegetable oil components formed by the complex multi-component mixtures of fatty acids and glycerol ester accelerates the studies in this field even more. In this study, the chemical compositions of vegetable oils hybridized with different resins, the chemical structures of pure vegetable oils, the different varieties among these vegetable oils, and various types of biocomposites produced using vegetable oil-based resins were investigated. In addition, the latest trends in other applications of these bio-composites, especially in automotive, were examined.

Modification of crystalline graphitic carbon nitride for improve efficiency in photocatalytic destruction of volatile organic compounds (VOCs) under visible light irradiation

In this study, we show that the use of a mixture of melamine and oxalic acid during the synthesis of acid-treated crystalline graphitic carbon nitride samples significantly enhances its photocatalytic activity in VOCs destruction processes. The rate of photocatalytic ethanol destruction with the participation of modified crystalline graphitic carbon nitride obtained under optimal conditions is 67.1 μmol h−1, which is almost twice higher than sample synthesized in the absence of oxalic acid, and is two orders of magnitude higher than the activity of bulk g–C3N4. The synthesized materials were characterized using XRD, FT-IR, UV–Vis, PL, SEM, and EDXA methods. The high activity of the modified carbon nitride samples is attributed to increased light absorption in the visible region of the spectrum and better crystallinity, which can lead to more efficient separation and transport of photogenerated charges. To our knowledge, the effect of the simultaneous use of melamine and oxalic acid for obtaining acid-treated crystalline graphitic carbon nitride is, shown for the first time.

Structure and Properties of Thermally Stabilized and Ecologically Friendly Organic Cotton Fibers as a New Activated Carbon Fiber Precursor

Organic cotton precursor yarn was impregnated in an aqueous solution consisting of diammonium hydrogen phosphate (DAP), boric acid (BA), and urea (U) mixtures before the thermal stabilization stage and then subjected to heat treatments in an air environment at 245 °C. The effect of chemical pretreatment on organic cotton yarn was examined using methods such as X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and infrared (IR) spectroscopy. The XRD analysis revealed a gradual decrease in the crystalline structure, attributed to the disruption of intermolecular hydrogen bonds. DSC and TGA measurements showed an improved thermal stability due to the formation of pre-graphitic structures with aromatic entities at higher temperatures. For samples chemically impregnated and then stabilized, the char yield values increased from 25% to 68% at 500 °C and 23% to 53% at 1000 °C. Analysis of IR spectra indicated a gradual reduction in both intermolecular and intramolecular hydrogen bonds associated with dehydration and dehydrogenation reactions. The IR spectra also confirmed a decrease in crystallinity with increasing oxidation time, which is consistent with the findings from X-ray diffraction. In addition, the IR spectra showed the presence of C = C bonds, indicating the formation of a crosslinked ladder-like structure. The results showed that DAP-BA-U integration increased the thermal stability of organic cotton fibers and the obtained samples were ready for the next stage, carbonization.Graphical

Establishment of a Steatosis Model in LMH Cells, Chicken Embryo Hepatocytes, and Liver Tissues Based on a Mixture of Sodium Oleate and Palmitic Acid.

Research on hepatic steatosis in animal husbandry has been a prominent area of study. Developing an appropriate in vitro cellular steatosis model is crucial for comprehensively investigating the mechanisms involved in liver lipid deposition in poultry and for identifying potential interventions to address abnormalities in lipid metabolism. The research on the methods of in vitro liver steatosis in chickens, particularly the effects of different fat mixtures, is still lacking. In this study, LMH cells were utilized to investigate the effects of OA, SO, PA, SP, and their pairwise combinations on steatosis development, with the aim of identifying the optimal conditions for inducing steatosis. Analysis of triglyceride (TG) content in LMH cells revealed that OA and SP had limited efficacy in increasing TG content, while a combination of SO and PA in a 1:2 ratio exhibited the highest TG content. Moreover, Oil Red O staining results in LMH cells demonstrated that the combination treatment had a more pronounced induction effect compared to 0.375 mM SO. Additionally, RNA-seq analysis showed that 0.375 mM SO significantly influenced the expression of genes associated with fatty acid metabolism compared to the control group, whereas the combination of SO and PA led to an enrichment of key GO terms associated with programmed cell death. These findings suggest that varying conditions of cellular steatosis could lead to distinct disruptions in gene expression. The optimal conditions for inducing steatosis in LMH cells were also tested on chicken embryonic liver cells and embryos. TG detection and Oil Red O staining assays showed that the combination of SO and PA successfully induced steatosis. However, the gene expression pattern differed from that of LMH cells. This study lays the foundations for further investigations into avian hepatic steatosis.

Fabrication and Efficient Interfacial Assembly of Bright Red-Emitting Carbon Quantum Dots for Security-Warning Textiles.

Carbon quantum dots (CQDs) have attracted more attentions due to their multiple performances. However, the fabrication of long-wavelength emitting CQDs with aliphatic precursors still remains a challenge, mainly because it is difficult to generate large sp2 domains to reduce energy gap, which is not conducive to a redshift of the luminescence peak. Hereon, by regulating the pH of citric acid and thiourea mixture, a N, S co-doped CQD emitting bright red fluorescence at 635nm is successfully fabricated through the solvothermal reaction under acidic condition, achieving a high quantum yield of 32.66%. Solvatochromic effects of the CQDs are discussed through theoretical equations and models, which confirm that the hydrogen-bonding interaction dominates the fluorescence emission behavior of CQDs in polar solvents. Besides, a feasible strategy is proposed to prepare an anti-counterfeiting textile via the deposition of red-emitting CQDs onto cotton fibers, through rapidly evaporating the preferred organic solvent. As expected, the CQD-decorated textiles exhibit encouraging anti-counterfeiting and security-warning functions, along with underwater and long-distance detectability, washability, and sun resistance. It is worth noting that the present work is innovative in realizing the application of red-light-emitting CQDs in the fields of security-warning textiles.

Strategies for regulating crystallinity and surface quality based on solvent multistage volatilization

In this paper, Bi2212 superconducting thin films were prepared with metal acetate as salt source and a mixture of acetic acid and N,N-dimethylformamide (DMF) as solvent. The volatilization process of the solvent was regulated by changing the ratio of the mixed solvent, which in turn achieved the regulation of the surface morphology and crystallinity of the Bi2212 superconducting films. The mechanism of the mixed solvents on the crystallinity and surface quality of Bi2212 superconducting films was systematically investigated. The results showed that the Bi2212 superconducting films were all (00l) epitaxial growth. The grain size of Bi2212 increased continuously with the increase of the proportion of acetic acid in the solvents. The grain size of the largest grain size was 43.8 nm when the proportion of acetic acid was 80 %. However, the high proportion of acetic acid in the mixed solvents reduced the surface quality of Bi2212 thin films. The minimum surface roughness was 15.0 nm at 40 % acetic acid. All the samples exhibited good superconducting properties. This work provides a research basis for the systematic preparation of multicomponent oxide thin films.

Study of Plugging Compositions Based on Synthetic Resins for Repair and Insulation Work in Wells.

This research is aimed at analyzing existing plugging compositions and developing a new plugging composition based on phenol-formaldehyde resin. This paper presents the results of studies of a hardening composition based on phenol-formaldehyde resin for repair and insulation work in wells. The plugging composition consists of two parts: Component "A" (resin and additives) and Component "B" (hardener). A resol-type water-soluble phenol-formaldehyde resin was selected for testing. The resin was additionally modified with special additives to improve performance properties. A mixture of acids was chosen as a hardener. Concentrations of resin and hardener were selected to ensure optimal loss of fluidity of the composition for different temperatures. The main physicochemical properties of the plugging composition were determined. The elastic-strength characteristics of the developed composition after curing at various temperatures (Poisson's ratio, Young's modulus, and compressive strength) were assessed. It has been experimentally proven that samples based on phenol-formaldehyde resin do not collapse completely under load but undergo longitudinal and transverse deformations. As the amount of hardener in the system increases, the compressive strength decreases. The presence of the elastic-strength properties of cementing compositions based on synthetic resins distinguishes them favorably from hardening compositions based on cement and microcement.

Screening and safety assessment of migrating substances released from biodegradable packaging materials into milk

Biodegradable polymeric packaging materials are being studied for their potential to replace traditional petroleum-based ones for food contact applications. However, potential safety concerns associated with the utilization of these biodegradable polymers have not been studied in detail. In this study, we conducted non-targeted screening and migration studies on two types of biodegradable milk packaging materials, which were composed of a mixture of polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS), and cellulose. In particular, we monitored the transfer of migrating substances from the packaging materials into a food simulant (50% ethanol) and into a real food (fat free and whole milk). A screening study identified seven compounds in the biodegradable packaging bags, including degradation products of antioxidants, lubricants, and plasticizers such as triethylene glycol, diethyl succinate, glycerin, 2,4-di-tert-butylphenol, and 13-docosenamide were identified. The migration studies indicated that the types and amounts of migrating substances transferred into the real food were appreciably lower than those transferred into the food simulant. Most of the detected migrating substances were below the levels established in the European Union regulations. However, the triethylene glycol levels (68-144 mg/kg) in the food simulant exceeded the limits (60 mg/kg) for one of the packaging materials tested. A safety assessment suggested that there is a low level of safety risk associated with one of the biodegradable packaging materials. This study provides important insights into the safety of biodegradable packaging materials that might be used in the food industry.