Formation Of Degradation Products Research Articles

Accelerated Predictive Stability Testing: Accelerating Registration Phase and Application of Reduced Designs for Shelf-Life Determination of Parenteral Drug Product

Objectives: This article explores the applicability of the accelerated stability assessment program (ASAP) in stability studies for parenteral medications. Conventional stability testing requires extensive evaluation over the entire shelf life of a product, which can be very time-consuming. In contrast, ASAP provides an efficient approach to support drug product development and expedite regulatory procedures. Methods: The study involved subjecting the medication to different stress and long-term stability conditions and monitoring the formation of degradation products. A systematic methodology was employed to evaluate the stress stability data of the parenteral medication using various designs (full and reduced). ASAP models were then developed from these data and assessed using the statistical parameters R2 (coefficient of determination) and Q2 (predictive relevance). To validate the accuracy of the models, the predicted levels of degradation products from each of the 13 models were compared with the actual long-term stability results using the relative difference parameter. Results: The results confirmed the suitability of the evaluated full model and 11 reduced models for predicting degradation products, except for the two-temperature model, demonstrating the effectiveness of ASAP in stability studies and providing reliable predictions. However, the three-temperature model was identified as the most appropriate model for the parenteral medication under investigation. The statistical analyses showed high R2 and Q2 values, indicating robust model performance and predictive accuracy. Consequently, we applied the selected model on various formulations, demonstrating the suitability of the model and impurity levels below the ICH specification limit. Conclusions: This research enhances understanding of how ASAP designs can be applied to stability studies for parenteral medications and demonstrates the significance of the application of ASAP during drug product development to expedite the initiation of procedures and implement post-approval variations.

Oxidative Destruction of p‐Chloroaniline in a Dielectric Barrier Discharge at Atmospheric Pressure in Oxygen

ABSTRACTThe paper presents the results of studies of the kinetics of decomposition of an aqueous solution of p‐chloroaniline (PCA) under the action of a dielectric barrier discharge at atmospheric pressure in an oxygen flow. The range of PCA concentrations was 10–150 mg/L, and the power density was 1.3 W/cm3. It was found that the decomposition of PCA proceeds formally according to the 1st kinetic order equation with a rate constant of (3.1–1.1) s‐1. The energy yield of decomposition (number of decomposed molecules per 100 eV of input energy) was 0.071–0.38. Data on the kinetics of the formation of degradation products (NH4+, NO2−, NO3−, Cl−, CO, CO2, carboxylic acids, aldehydes), as well as the results of biotesting of treated solutions are presented.

Characterization of main degradation products from dendrobine under stress conditions by multistage cleavage of UPLC-ESI-IT-TOF.

Dendrobine is a sesquiterpene alkaloid primarily used in the treatment of inflammatory diseases, immune system disorders, and conditions related to oxidative stress. To understand the possible degradation pathways of dendrobine for its quality control, we conducted an in-depth investigation of its degradation products using forced degradation methods. The separation of dendrobine and its degradation products was achieved on a Shim-pack XR-ODS III (75 mm × 2 mm, 1.6 µm) column with a methanol-water mixture as the mobile phase under isocratic conditions, the isolated compounds were examined in positive ion mode with an ion trap-time of flight mass spectrometer (IT-TOF). In order to obtain in-depth structural information about the degradation products, mass spectrometry was performed using a five-stage fragmentation approach. This method allowed for thorough structural clarification via several rounds of selective fragmentation and high-resolution detection. System control and data acquisition were managed using LCMSsolution 3.81 software. The results showed that dendrobine undergoes significant degradation under oxidative, acidic, hydrolytic and thermal conditions, resulting in the formation of several degradation products with notable structural changes. Under oxidative conditions, dendrobine primarily generates two degradation products with mass increases of 16 Da and 32 Da, indicating mono-oxidation and di-oxidation reactions. Acidic degradation led to the identification of three degradation products, including a novel compound with an 18 Da mass increase, suggesting potential hydrolysis or dehydration reactions. Hydrolytic and thermal conditions resulted in the formation of two and three degradation products, respectively, with structural changes indicating possible molecular cleavage and reorganization mechanisms. In contrast, dendrobine exhibited strong stability under alkaline and photolytic conditions, with no significant degradation products detected. Detailed characterization of the degradation products via multi-stage mass spectrometry revealed key reaction pathways and mechanisms involved in dendrobine's degradation, providing critical insights for assessing its chemical stability and optimizing storage conditions.

Kinetics of human insulin degradation in the solid-state: an investigation of the effects of temperature and humidity.

With the increasing development of oral peptide dosage forms, a comprehensive understanding of factors affecting peptide drug stability in the solid-state is critical. This study used human insulin, as a model peptide, to examine the individual and interactive effects of temperature and humidity on its solid-state stability. Insulin was stored at temperature (25°C, 40°C, and 6 °C) and humidity (1%, 33% and 75%) over 6 months. Primary degradation pathways were deamidation and covalent aggregation. Degradation product formation rates were determined empirically and modelled using the humidity-corrected Arrhenius equation. Temperature had a major impact on deamidation and covalent aggregation rates, with the reaction rates increasing with temperature. The effect of humidity was temperature dependent. Moisture induced degradation was minimal at 25°C and 40°C, but an important factor at 60°C. Dynamic vapour sorption analysed determined a clear differences in insulin moisture sorption characteristics at 60°C relative to 25°C and 40°C. The findings suggest that the effect of moisture on insulin deamidation and covalent aggregation rates was not a function of water content but the nature of the insulin moisture interaction.

Deep Insight into Reactivity of Li3PS4 Electrolyte for Solid Li-Ion Batteries Towards Humidity Using Large Instruments

Wide commercialization of Li-ion batteries (LIBs) for electric transport stimulates a demand for safer batteries with higher energy density. Thiophosphate solid electrolytes (TSEs) for LIBs are one of the most promising candidates to replace a classical liquid electrolyte with volatile components owing to their high ionic conductivity values and appropriate mechanical properties for processing [1]. However, one of the main drawbacks of TSEs is their high sensitivity towards humidity even in trace amounts. The reactivity with water and moisture impacts the electrochemical properties of the electrolytes and leads to toxic H2S emissions. This aspect plays a crucial role for the choice of LIB manufacturing environment (dry room characteristics) and requires fine understanding of underlying mechanisms to optimize a performance / cost ratio for solid-state batteries (SSBs).In the present study, a unique combination of characterisation methods was applied to investigate the reaction between densified Li3PS4 pellet and different levels of humidity (dew point (DP) -40 °C and DP=12 °C for 15 min and 2 h) from chemical and morphological/microstructural points of view. H2S gas evolution was accurately quantified upon a TSE exposure to humid atmosphere using a home-made flow-through setup with differentiation between surface and bulk pellet reactivity [2]. Further, top-view propagation of Li3PS4 pellet degradation was investigated using SEM and EDX techniques showing fractures generated through gas released leading to some increase in the pellet porosity at DP= -40 °C; apparition of cracks and oxygen content raise in case of DP = 12 °C exposure. The bulk of the exposed pellets was probed using non-destructive X-ray nanotomography (ESRF, ID16b). Different scenarios were observed at low and high levels of humidity during 15 min and 2 h of the pellet exposure (see Fig.). Degradation front containing large pores and cracks propagated up to 50 µm to the depth of the pellet (~400 µm total thickness) after 2 h of exposure to DP= 12 °C. X-ray diffraction-computed tomography (XRD-CT, ESRF, ID15a) was employed to observe structural changes in 3D for Li3PS4 SE upon its reaction with humidity at different depths. Minor changes were find in crystalline structure of Li3PS4 after DP= -40 °C exposure while a reaction at DP=12 °C provoked formation of new phases propagating up to 90 µm depth of the pellet. Some of newly formed compounds were identified, i.e. P2S2O3, Li2HPO3, P2O5 and Li2S2O6.2H2O. Structural strains for Li3PS4 crystalline phase after its exposure to DP=12 °C were revealed thanks to advanced XRD-CT analysis. Finally, the impact of the pellet exposure to humidity at different conditions on its ionic conductivity was investigated.As a result of this study, a solid link was found between the morphological, microstructural, chemical degradation of the TSE and its ionic conductivity upon reaction with water. It was evidenced that the crack formation and propagation to the bulk of TSE pellet is a result of a complex cyclic mechanism, which includes chemical attack of H2O molecules on Li3PS4 pellet surface, creation of mechanical strain for the TSE lattice, formation of solid degradation products and gaseous H2S, crack propagation due to the strain release and the gas evolution, further penetration of water to the bulk of the pellet, etc. To the best of our knowledge, this is a first comprehensive study of reaction between SSE and humidity taking into account all the aspects above. This work contributes to understanding of key triggers for TSE deterioration in contact with different concentrations of water and to definition of proper environment for solid-state batteries production and handling.Beamtime at the ESRF was granted within the Battery Pilot Hub MA4929 “Multi-scale Multi-techniques investigations of Li-ion batteries: towards a European Battery Hub.

Operando Dilatometry and Gas Analysis of Na-Hard Carbon Half Cells with Carbonate Electrolytes

Sodium-ions that are dissolved in carbonate-based electrolytes do not intercalate well into graphite. Therefore, alternative anode materials are needed for sodium-ion batteries (SIB). Hard carbon anodes are a promising and widely used negative electrode for SIB, showing reversible gravimetric capacities in the range of 150-350 mAh g-1. [1] Volume changes and parasitic side reactions with the electrolyte are undesirable ageing effects which can happen during cycling and shorten the lifespan of a battery. Operando dilatometry and operando mass spectrometry are useful methods to characterize possible degradation mechanisms.In this work we analyzed the volume changes of hard carbon electrodes in carbonate electrolytes during cycling with operando dilatometry, paying special attention to irreversible volume changes e. g. due to sodium plating. In addition, we carried out operando mass spectrometry to investigate gaseous substances produced due to the parasitic side reactions at the electrodes. Gas chromatography mass spectrometry (GC-MS) reveals the relevant species. The electrolyte consisted of 1M NaPF6 dissolved in EC:DMC (1:1, by weight). All measurements were carried out in specially developed test setups.A relationship between the thickness change and voltage profile was established. The thickness changes can be correlated with the different storage mechanisms in the hard carbon electrodes. Additionally, the cyclic formation of the gaseous degradation products could be observed. A possible correlation between gas evolution and thickness change is discussed.In conclusion, the results of this study contribute to a more detailed understanding of possible degradation mechanisms that occur during cycling of hard carbon anodes in carbonate-based electrolytes. A better understanding of the degradation mechanisms could be used to develop strategies to mitigate the negative influence on battery cycle life.[1] Escher, I.; A. Ferrero, G.; Goktas, M.; Adelhelm, P.; In Situ (Operando) Electrochemical Dilatometry as a Method to Distinguish Charge Storage Mechanisms and Metal Plating Processes for Sodium and Lithium Ions in Hard Carbon Battery Electrodes. Adv Materials Inter 2021, 2100596. DOI: 10.1002/admi.202100596.

The Dual Role of Thiophosphate Solid Electrolytes as Catholytes and Active Material Precursors in Lithium/Sulfur Solid-State Batteries

Lithium/sulfur cell chemistry combines low material cost and high availability of sulfur with high specific energies. However, liquid electrolyte cells are plagued by the parasitic polysulfide shuttle effect between the electrodes, which reduces reversible capacity and efficiency and passivates the negative electrode. Inorganic solid electrolytes (SE) are single-ion conductors and can therefore block the parasitic electrode crosstalk by blocking polysulphide dissolution and transport. In particular, the combination of sulfur battery chemistry with thiophosphate-based SEs is considered obvious due to their high ionic conductivities and their electrochemical stability window corresponding to the usual voltage ranges used in lithium/sulfur battery chemistry.Lithium/sulfur solid-state batteries (SSLSBs) based on thiophosphate SE are generally reported to have higher capacities, based on the mass of active material, than their liquid counterparts. These can reach up to the theoretical capacity of sulphur (1672 mAh g-1) and even beyond, implying a capacity contribution from the SE and its degradation products. As the degradation products potentially block ionic conduction pathways, this is often considered undesirable. However, other work has reported stable cycling of carbon/SE composites without the addition of additional active material, postulating in situ formation of active material by degradation of the SE.In this work we show the capacity contribution of the SE by introducing a balance of charge and discharge capacity in SSLSBs. By comparing positive electrode composites with and without additional sulfur as an active material, we show the importance of the storage capacity contribution of the thiophosphate SE in state-of-the-art electrode composites. Using electrochemical and instrumental analysis (XPS, ToF-SIMS), we investigate the formation of degradation products during the first cycles and their reversible redox during cycling. Based on this, we postulate that a controlled amount of degradation may be useful in SSLSBs and that this additional role of SE as a contributor of charge storage capacity may be a design principle for the development of high capacity positive electrode composites.

Chemiluminescence-based evaluation of styrene block copolymers’ recyclability

The study presents the chemiluminescence based (CL) evaluation of the recyclability of linear styrene block copolymers. This analysis can provide insight into the material’s degradation state and predict its suitability for further recycling cycles, helping to avoid unnecessary energy consumption during processing.The thermal stability of four similar copolymer structures − styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS) copolymers with different styrene/butadiene ratios, and styrene-ethylene-butadiene-styrene (SEBS) − was studied using isothermal and non-isothermal chemiluminescence (CL). The activation energies for oxidative degradation were calculated based on oxidation induction times indicated by the CL intensities evolution. The results, which highlight the influence of molecular structure on stability under aging conditions, as presented by the calculated for the activation energy (kJ mol−1), show the following sequence: SBS (styrene 30%) (117 kJ mol−1) ≈ SIS 120 (kJ mol−1) < SBS (styrene 40%) (176 kJ mol−1) < SEBS (180 kJ mol−1). The CL data were correlated with infrared (IR) spectroscopy and differential scanning calorimetry (DSC) data, providing a comprehensive understanding of the thermal stability and degradation mechanisms during recycling proces. The sequence of the composing units determines the degradation process, with weaker points predominantly attacked in the linear moieties of isoprene, butadiene, and vinyl segments. The experimental data indicate that SIS and SBS (30% styrene) copolymers degrade the fastest likely due to the rapid accumulation of hydroperoxide radicals. The SEBS copolymer also experiences significant degradation, but this occurs at higher temperatures (above 220 ⁰C) and progresses more gradually once it begins. In contrast, the SBS copolymer with 40% styrene content degrades more slowly and exhibits minimal mass loss, primarily due to the formation of less reactive keto degradation products.

Photoprotection and its implications for drug safety

Appropriate photoprotection plays a key role in the safety of using medicinal preparations whose active substances may induce photosensitivity reactions. This aspect applies not only to drugs applied topically to the skin, but also systemically. Drug-induced photosensitivity reactions to light depend on the active substance contained in the medicinal product and its dose, which translates into the concentration in the skin, the type of ultraviolet radiation, its intensity and exposure time. The chemical structure of phototoxic drugs contains unsaturated chemical bonds and aromatic groups, which are responsible for the absorption of radiation, the formation of degradation products and/or free radicals and hypersensitivity reactions. Therefore, in order to prevent hypersensitivity reactions, it is necessary to use appropriate sun protection and/or avoid exposure to solar radiation during pharmacotherapy with selected groups of drugs. The paper presents the latest research results on the impact of drug-induced photohypersensitivity on the increased likelihood of skin cancer. Drugs with the potential to induce photohypersensitivity reactions are discussed, including information on the relationship between their long-term use and the incidence of skin cancer. Based on the data contained in the Product Characteristics, exemplary indications regarding the appropriate photoprotection method to ensure the safe use of the medicinal product are presented. Med Pr Work Health Saf. 2024;75(5):475-484.

Influence of UV-B and culinary treatment on vitamin D2 and agaritine in button mushrooms

This study investigated the effects of different culinary treatments on the levels of vitamin D2 and agaritine in irradiated white button mushrooms. In addition, the intake of this vitamin via mushroom dishes was evaluated. In fresh irradiated white button mushrooms, the vitamin D2 content was 21.5 ± 2.4 µg/100 g fresh weight, 42 % of which was in the cap skin. The highest losses of vitamin D2 (63 %) were found in samples boiled in acidic water. In contrast, the lowest losses were found in samples boiled in non-acidified water. In the baking and frying experiments, vitamin D2 retention depended more on the cooking time than on the temperature. This resulted in high-heat frying being the second-best treatment for retaining vitamin D2 content in the samples. In the case of agaritine, no effect of UV treatment on its content was observed, and cooking treatment reduced its consumption. At the same time, the formation of toxic degradation products was not observed. The Recommended Daily Intake (RDI) of vitamin D can be achieved by consuming about 75–190 g of cooked, irradiated white button mushrooms, which can thus be an important dietary source of this vitamin.

Simultaneous Overcoming Approach for Poor Wettability and Low Stability in Stomach by Simple Methods; Formulation Design and Development of Monoacylglycerol Acyltransferase 2 Inhibitor, S-309309.

N-[(4R)-5,7-Difluoro-2'-(5-methylpyridin-2-yl)-4'-oxo-2,2',3,4',5',7'-hexahydrospiro[1-benzopyran-4,6'-pyrazolo[4,3-c]pyridin]-3'-yl]-2-(methanesulfonyl)acetamide (S-309309) is an anti-obesity drug developed by Shionogi & Co., Ltd. that has a monoacylglycerol acyltransferase 2 inhibitory effect. S-309309 has poor wettability, and the amount of the degradation product (4R)-3'-amino-5,7-difluoro-2'-(5-methylpyridin-2-yl)-2,2',3,7'-tetrahydrospiro[[1]benzopyran-4,6'-pyrazolo[4,3-c]pyridin]-4'(5'H)-one (compound 8) increases over time under acidic conditions. In this study, we have tried to improve S-309309 wettability and suppress the amount of degradation product increased under acidic conditions. As a result of the study, we found that by mixing with a water-soluble polymer, the wettability of S-309309 and its dissolved concentration in fluid were increased suggesting that its dissolution behavior should be enhanced. In addition, by encapsulating S-309309, the increase of degradation product amount was suppressed under acidic conditions, suggesting that the suppression of degradation product formation would be expected in the stomach after oral dosing. Overall, these results suggest that the drug property issues of S-309309 can be overcome by mixing S-309309 with a water-soluble polymer and encapsulation.

Enhancing the formation of functional glucosinolate degradation products in fermented broccoli stalk by-product with lactic acid bacteria

Broccoli stalk by-product (BsBP) is rich in glucosinolates (GSLs). Its fermentation process is generally characterized by the degradation of GSLs and formation of bioactive isothiocyanates (ITCs), in which lactic acid bacteria (LAB) play an important role. The GSLs-degrading capacity of 61 LAB strains was investigated in vitro. Lacticaseibacillus paracasei YC5, Pediococcus pentosaceus RBHZ36, and Lactiplantibacillus plantarum ND1, with high potential to transform GSLs into ITCs, were screened. The functional GSL degradation products (total content of sulforaphane, indol-3-carbinol, and ascorbigen) increased 22.0–33.5 % compared to natural fermentation after 24 h when BsBP was fermented by the three screened strains in pure culture. LAB fermentation also helped to increase the quantity of indolic GSL degradation products in BsBP brine, suggesting that LAB fermentation promoted BsBP GSLs transformation into bioactive ITCs. The proposed use of the LAB strains characterized in this study provided a fermented BsBP and brine with high profile of functional GSL degradation products.

Improved Corona Resistance of Epoxy Resin for Gas‐Insulated Equipment in Nitrogen Gas by Direct Fluorination

Direct fluorination has demonstrated efficacy in modulating the surface electrical properties of epoxy insulators and preventing surface charge accumulation. Comparative corona treatments were conducted on both surface fluorinated (modified) epoxy samples and untreated (virgin/original) samples using a modified electrode setup in a nitrogen (N2) atmosphere. The purpose was to evaluate the resistance of the modified epoxy surface layer against corona discharge. The results of ATR‐IR analysis and SEM surface and cross‐sectional imaging indicate that corona treatment did not alter the chemical composition of the fluorinated sample or the thickness of the fluorinated layer. Based on assessments of potential decay and water contact angle measurements, the surface conductivity of the modified sample was decreased by corona treatment. The wettability of fluorinated sample remained unchanged after corona treatment, and no soluble degradation products were produced. Conversely, the surface conductivity of the virgin sample exhibited an increase following corona treatment, accompanied by the formation of soluble degradation products. These results confirm that direct fluorination improves the epoxy insulator's discharge resistance in N2 and provides technical support for enhancing the electrical performance of epoxy insulators in gas insulated equipment. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Degradation Mechanism and Enhanced Stability of Organolithium for Chemical Lithiation

AbstractOrganolithium solutions, especially Li‐arene solutions (LASs) with high reactivity and controllable redox potentials, have gained significant attention because of their wide applications in chemical lithiation, liquid anodes, and battery recycling. However, the sudden loss of reactivity when stored or applied at room temperature is still puzzling and inhibits the application of LASs. In this work, the degradation mechanism of LASs is fully investigated and revealed by combining various experimental characterization and computational simulations. A hierarchical reaction mechanism for lithium biphenyl/2‐methyl tetrahydrofuran (Li‐Bp‐2MT), a lithiation solution used for most anodes, explains degradation and side product formation. Specifically, the dimerization of the active component Li1Bp[2MT]1 forms an inactive dimer that is irreversibly reduced in the presence of locally accumulated highly reductive Li0. This reaction mechanism reveals the atomic origins of lithiation solution deactivation and accounts for all solid and gaseous byproducts. LiH is identified as the dominating solid byproduct, indicating irreversible destruction of the active components and facilitating side reactions producing H2 and CH4. Based on reaction mechanism insights, modifying molecular interactions and reaction kinetics are experimentally shown to inhibit Li0 aggregation kinetics, enhancing long‐term prelithiation performance. This research provides comprehensive guidelines for practical applications of LASs.

Degradation of the AMP/PZ-based solvent CESAR1 and effects of solvent management in two longtime pilot plant tests

Two 24/7 longtime testing campaigns at the CO2 capture pilot plant at Niederaussem with an accumulated testing time of more than 40,000 h with the CESAR1 solvent, an aqueous solution of 26.7 wt% 2-amino-2-methylpropan-1-ol (AMP) and 12.9 wt% piperazine (PZ), provide a unique data base for the development of solvent management technologies and the evaluation of hypotheses on amine degradation. In the first campaign with a testing time of 34,000 h without replacement of the solvent inventory, three solvent management strategies with different effect mechanisms were investigated: adsorptive removal of trace elements from the solvent by two kinds of active carbon, removal of ionic contaminants by ion exchange using cation and anion exchange resins, and removal of NO2 from the flue gas by treatment with a thiosulfate/sulfite solution. After replacement of the solvent inventory the second campaign was conducted, in which none of the solvent management technologies mentioned have been applied for 10,000 h. The results of the two campaigns allow a direct comparison of the solvent degradation behavior. It is shown that active carbon does not significantly affect the accumulation rate of degradation products in CESAR1, and that an inappropriate kind of active carbon can cause foaming. Anionic degradation products, metal complexes, trace components and cationic contaminants can be effectively removed from the aged solvent by ion exchange. However, after their removal, accelerated formation of oxidative degradation products by a factor of up to 3 higher than before the anion exchange was observed. Removal of NO2 from the flue gas did not affect the NH3 emissions from the CO2 absorber, but it led to the highest observed increase rate of the accumulation of acidic degradation products for aged CESAR1. The results show that exaggerated efforts for solvent management are contra-productive and that a reassessment of the effect mechanisms of solvent management technologies is necessary.

Consecutive pozzolanic layerings to depress internal-sulfate-attack corrosion of OPC by phosphogypsum-based cold bonded aggregates

Phosphogypsum-based cold bonded aggregates (PCBAs), as incorporates excessive soluble sulfate, potentially induce Internal Sulfate Attack (ISA) corrosion to OPC, which severely constrains its utilization and advancement. This work applies consecutive pelletization using pozzolanic layerings (fly ash (FA) and phosphorus slag (PS) basis) for surface modification. The basic, exterior hydration and microstructure properties of PCBAs, as well as the interfacial corrosions of PCBAs-OPC, are investigated via XRD, TG-DTG, X-CT, SEM-EDS, μ-XRD, and nanoindentation technologies. Results indicate the FA and PS layerings block sulfate leaching by 15–30%. When blended with OPC, these layerings capture releasable sulfate within PCBAs exterior via interfacial hydration that also depletes portlandite to generate tighter ITZ. Therefore, the reactive layerings effectively alleviate ISA corrosion via in-front blockage and back-end reaction, as supported by reduced sulfate ingress within 30–40 μm, less degradation products (ettringite and gypsum) formation, and improved hardness of vicinity OPC. The FA-based layering performs slightly poorer due to its lower density causing inefficient consolidation of PCBAs. Consequently in macroscopic, the ISA-inducing fissures of concrete surface are diminished, followed by improved 90-d compressive strength from 36.43 MPa to optimally 48.38 MPa. This study elucidates the rich-gypsum aggregates-type ISA corrosion mechanisms to OPC and proposes an instructive solution using pozzolanic layerings.

Towards Reducing Food Wastage: Analysis of Degradation Products Formed during Meat Spoilage under Different Conditions.

Foodstuffs, particularly perishable ones such as meat, are frequently discarded once the best-before date has been reached, despite the possibility of their continued suitability for human consumption. The implementation of intelligent packaging has the potential to contribute to a reduction in food wastage by enabling the monitoring of meat freshness during storage time independently of the best-before date. The process of meat spoilage is associated with the formation of specific degradation products, some of which can be potentially utilized as spoilage indicators in intelligent packaging. The aim of the review is to identify degradation products whose concentration correlates with meat shelf life and to evaluate their potential use as spoilage indicators in intelligent packaging. To this end, a comprehensive literature research was conducted to identify the factors influencing meat spoilage and the eight key degradation products (carboxylic acids, biogenic amines, total volatile basic nitrogen, aldehydes, alcohols, ketones, sulfur compounds, and esters) associated with this process. These degradation products were analyzed for their correlation with meat shelf life at different temperatures, atmospheres, and meat types and for their applicability in intelligent packaging. The review provides an overview of these degradation products, comparing their potential to indicate spoilage across different meat types and storage conditions. The findings suggest that while no single degradation product universally indicates spoilage across all meat types and conditions, compounds like carboxylic acids, biogenic amines, and volatile basic nitrogen warrant further investigation. The review elucidates the intricacies inherent in identifying a singular spoilage indicator but underscores the potential of combining specific degradation products to expand the scope of applications in intelligent packaging. Further research (e.g., storage tests in which the concentrations of these substances are specifically examined or research on which indicator substance responds to these degradation products) is recommended to explore these combinations with a view to broadening their applicability.

Vaterite-based in situ surface modification and process-dependent biocompatibility of laser sintered polypropylene

Polypropylene (PP) rapidly gains scientific attention as fatigue-resistant and lightweight tissue repair and implant material, while emerging laser-sintering based methods for PP processing further allow unlimited versatility of PP specimens and often reduced numbers of process steps, substituting traditional manufacturing approaches. Generally, PP is considered biocompatible for a variety of medical applications while showing superior long-term stability, however, thermoplastic processing of polypropylene may induce the formation of cytotoxic degradation products, necessitating its cytotoxicological assessment. In the present study, PP specimens have been fabricated using warm, quasi-isothermal and complementary cold, non-isothermal powder bed fusion (PBF), allowing processing PP at ambient powder bed temperature of 25 °C for minimizing thermal exposure and the formation of decomposition products. The surface of manufactured specimens has been modified with hybrid coatings consisting of mesoporous inorganic microcrystals of vaterite laden with model biomacromolecules, i.e., fluorescently labelled dextran, demonstrating the stable coating and attachment of dextran-loaded vaterite crystals independent of the applied PBF processing regime. Vaterite coating is degradable and enables the opportunity to endow the surface of PP with sustained release functionalities. Both coated and uncoated specimens demonstrated excellent biocompatibility independent of the applied processing regime, as evaluated in an ex ovo shell-less hen's egg model.

Aflatoxin B1 Control by Various Pseudomonas Isolates.

The climate-change-coupled fungal burden in crop management and the need to reduce chemical pesticide usage highlight the importance of finding sustainable ways to control Aspergillus flavus. This study examines the effectiveness of 50 Pseudomonas isolates obtained from corn rhizospheres against A. flavus in both solid and liquid co-cultures. The presence and quantity of aflatoxin B1 (AFB1) and AFB1-related compounds were determined using high-performance liquid chromatography-high resolution mass spectrometry analysis. Various enzymatic- or non-enzymatic mechanisms are proposed to interpret the decrease in AFB1 production, accompanied by the accumulation of biosynthetic intermediates (11-hydroxy-O-methylsterigmatocystin, aspertoxin, 11-hydroxyaspertoxin) or degradation products (the compounds C16H10O6, C16H14O5, C18H16O7, and C19H16O8). Our finding implies the upregulation or enhanced activity of fungal oxidoreductases and laccases in response to bacterial bioactive compound(s). Furthermore, non-enzymatic reactions resulted in the formation of additional degradation products due to acid accumulation in the fermented broth. Three isolates completely inhibited AFB1 or any AFB1-related compounds without significantly affecting fungal growth. These bacterial isolates supposedly block the entire pathway for AFB1 production in the fungus during interaction. Apart from identifying effective Pseudomonas isolates as potential biocontrol agents, this work lays the foundation for exploring new bacterial bioactive compounds.

Degradation pathways and product formation mechanisms of asphaltene in supercritical water

Asphaltene is the compound with the most complex structure and the most difficult degradation in oily sludge, which is the key to limit the efficiency of supercritical water oxidation treatment of oily sludge. In this paper, the supercritical water oxidation process of asphaltene was investigated in terms of free radical reaction, degradation pathway, and product generation mechanism using ReaxFF molecular dynamics simulation method. The results showed that increasing temperature, increasing O2, and increasing H2O have different effects on HO2·generation. Benzene rings undergo fusion and condensation through hydrogenation abstraction and oxygen addition reactions, subsequently breaking down into long-chain alkanes. Increasing O2 can effectively promote the ring-opening of nitrogen-containing heterocycles. -COOH is the most important intermediate fragment for CO and CO2 generation, and there is a reaction competition with -CHO3 and -CO3. When the number of oxygen molecules increases from 300 to 700, the reaction frequency of -CHO3 and -CO3 to generate CO and CO2 increases by 17.14 % and 12.77 %·H2O determines the production of H2 by controlling the number of H·radicals present. As the amount of H2O increases from 500 to 1500, the product ratio of H2 increases from 12.73 % to 21.31 %. Environmental implicationAsphaltene is the most structurally complex organic matter in oily sludge, and its presence makes it difficult for oily sludge to be completely degraded by conventional treatment methods such as pyrolysis and incineration. Polycyclic aromatic hydrocarbons (PAHs) represented by asphaltene increase the carcinogenicity and mutagenicity of oily sludge, and even irreversibly pollute soil and groundwater. Supercritical water oxidation, as an efficient organic waste treatment technology, can realize harmlessness in a green and efficient way. So the study on the mechanism of supercritical water oxidation of asphaltene is of great significance for environmental protection.