Search Results (204)

Nitrosamines (NAs) pose a risk due to their carcinogenic properties, especially in processed and cured meats where nitrites and nitrates are widely used. The objective of this study was to develop an integrated Ultra-High-Performance Liquid Chromatography–High-Resolution Mass Spectrometry (UHPLC–HRMS) workflow for detecting both volatile (VNAs) and non-volatile (NVNAs) nitrosamines in meat matrices. Comparison of two ionization techniques showed that heated electrospray ionization (HESI) and atmospheric pressure chemical ionization (APCI) provided complementary coverage and sensitivity. Extraction and cleanup were optimized for meat, although recovery rates remained variable, underscoring the analytical complexity. The method was applied to raw, cooked, cured, and grilled meats, as well as to in vitro gastric digestion and co-digestion with spinach. Results revealed that some NAs were present even in untreated raw meat (≈3.0 µg/kg, N-nitrosodi-n-butylamine), while the addition of nitrites and nitrates significantly increased their levels (more than 10 µg/kg, N-nitrosodiethylamine, N-nitrosodimethylamine, N-nitrosodi-n-butylamine). Gastric digestion was the most critical condition, further promoting nitrosamine formation, particularly for N-nitrosodiethylamine, N-nitrosodi-n-butylamine, and N-nitrosopiperidine. Ascorbate exhibited a dual role, acting as an inhibitor at low nitrite concentrations but becoming pro-oxidant at high levels (300 mg/kg). Cooking alone had limited impact, whereas cooking combined with digestion yielded the highest and most consistent nitrosamine concentrations. The inclusion of spinach during digestion modestly altered nitrosamine levels, reflecting both its nitrate content and polyphenolic profile. Nonparametric ANOVA (aligned rank transform) confirmed that preservative treatment, rather than processing or interaction effects, was the main driver of variability (total nitrosamines: H = 24.15, p = 2.33 × 10⁻⁵), with the combination of preservative ascorbate plus nitrite producing significantly higher levels than other treatments (q = 0.000656). N-nitrosodimethylamine consistently emerged as the most relevant marker for dietary exposure, in agreement with EFSA guidance. Overall, this study underscores both the analytical and biochemical complexity of nitrosamine detection and formation in meat products, while highlighting the importance of preservative formulation and the potential role of dietary antioxidants in mitigating exposure. Full article

For the first time, the kinetics of isothermal curing and thermal degradation of polyethylene glycol maleate (pEGM)–based systems and their composites with mineral fillers were investigated in the presence of a benzoyl peroxide/N,N-Dimethylaniline redox-initiating system. DSC analysis revealed that the curing process at 20 °C can be described by the modified Kamal autocatalytic model; the critical degree of conversion (α_c) decreases with increasing content of the unsaturated polyester pEGM and in the presence of fillers. In particular, for unfilled systems, α_c was 0.77 for pEGM45 and 0.60 for pEGM60. TGA results demonstrated that higher pEGM content and the incorporation of fillers lead to increased thermal stability and residual mass, along with a reduction in the maximum decomposition rate (dTGₘₐₓ). Calculations using the Kissinger–Akahira–Sunose and Friedman methods also confirmed an increase in the activation energy of thermal degradation (E_a): E_KAS was 419 kJ/mol for pEGM45 and 470 kJ/mol for pEGM60, with the highest values observed for pEGM60 systems with fillers (496 kJ/mol for SiO₂ and 514 kJ/mol for CaCO₃). Rheological studies employing three-interval thixotropy tests revealed the onset of thixotropic behavior upon filler addition and an increase in structure recovery after deformation of up to 56%. These findings underscore the potential of pEGM-based systems for low-temperature curing and for the design of composite materials with improved thermal resistance. Full article

The high density of the internal structure of new-generation cementitious composites, such as high-performance and ultra-high-performance concretes, necessitates the use of advanced methods for evaluating their transport properties, particularly those employing a gaseous medium. The developed gas permeability method for cement pastes, based on a modified RILEM-Cembureau approach, has proven to be highly accurate, reliable, and extremely sensitive to changes in the porosity characteristics of such composites. The article contains the results of a study of the mass transport capabilities of blended cement pastes, characterised by variable water–cement ratios. Two types of cements were used in the study: with the addition of fly ash and blast furnace slag. Ordinary Portland cement was used as the reference binder. The tests were conducted after long-term curing under natural conditions, i.e., after 90 days and 2 years. The assessment of open porosity was carried out through three techniques: helium pycnometry, mercury intrusion porosimetry, and water saturation. Permeability, on the other hand, was measured using a customized approach tailored for uniform paste materials. Microstructural changes were also analysed in the context of natural hydration carbonation progress. The results presented allowed a quantitative description of the effects of the w/c ratio, the presence of additives, and the progress of hydration and carbonation on the porosity of pastes and their permeability to gas flow. The two-year curing period of the pastes exposed to natural CO₂ resulted in a reduction of the permeability coefficient k ranging from 11% to 74%, depending on the type of cement and the water-to-cement (w/c) ratio. This decrease was caused by the continued progress of hydration and simultaneous carbonation. The results of the research presented are of interest from both an engineering and scientific point of view in the context of long-term microstructural changes and the mass transport abilities of cement pastes associated with these processes. The extensive range of materials compositions investigated makes it possible to analyse the durability and tightness of many cementitious composites over long periods of service. Full article

This study aims to evaluate the usability of agricultural wastes such as rice husk ash (RHA) and garlic husk ash (GHA) in improving silt soils by the alkali activation method. During the stabilization process, samples prepared with binder systems containing sodium hydroxide (SH) and sodium silicate (SS) at different SH/SS ratios (1, 3, and 9) and additive rates (0%, 4.5%, and 9%) were cured in two different curing environments (cured at ambient temperature—AC and cured in oven at 35 °C—OC) for 7, 28, 56, and 90 days. Mechanical behavior was evaluated by unconfined compressive strength (UCS) and unconsolidated-undrained triaxial compression (UU) tests; environmental strength was analyzed by 25 and 50 cycles of freeze–thaw (F–T) tests. Microstructure development was investigated by SEM and XRD analyses, while sustainability assessment was carried out with carbon footprint (kg·CO₂/kg) and carbon efficiency (CI) parameters. The findings showed that mixtures containing 9% RHA and a high SH/SS ratio provided high strength in both AC and OC environments. While using GHA alone provided limited mechanical performance, it increased the binding capacity by creating a synergistic effect when used with RHA. Oven-curing environment increased the speed of pozzolanic reactions and the development of the binder phase, resulting in denser microstructures. In addition, the RHA additive played a critical role in maintaining the resistance against freeze–thaw cycles. Carbon emission analyses revealed that SH and SS had high carbon loads, while RHA and GHA additives provided environmentally sustainable solutions with low carbon footprint and high strength. As a result, alkaline activation systems with RHA and GHA additives offer a strong alternative for sustainable soil improvement applications with high strength and environmental durability. Full article

The use of supplementary cementitious materials and the CO₂ uptake capacity of cementitious materials—including recycled concrete aggregates—not only promotes the circular economy but may also present an opportunity to increase their ecoefficiency, thus improving the shrinkage and durability properties of concretes. This study analyses the impact of carbonated recycled aggregates and CO₂ curing on improving the properties of commercial structural self-compacting concrete. Recycled aggregate concretes (RACs) were produced using 50% and 60% coarse recycled concrete aggregate (RCA), in carbonated and uncarbonated forms, and two types of cement—ordinary Portland cement (CEM I) and CEM II/B-M Portland composite cement containing 24% less clinker than CEM I—all with similar compressive strengths. After evaluating the CO₂ curing process, the physical, mechanical, shrinkage, and durability properties (including suction and carbonation resistance) of the concretes were assessed. The properties of the RACs were compared with those achieved by conventional concrete, to generate insights for developing a highly sustainable concrete manufacturing process. Taking all the assessed properties into account, the CO₂ curing process improved concrete’s properties. In addition, RAC-C50-I concrete (using CEM I with carbonated RCA) and RAC50-II (using CEM IIB and uncarbonated RCA) exhibited the greatest durability, resulting in reductions in sorptivity values of 40% and 45%, and decreases in the carbonation coefficient of 16% and 21%, respectively, compared to concrete without CO₂ curing. Full article

Magnesium slag (MS) is a solid by-product during magnesium production using the Pidgeon process. Around 5–6 million tons of magnesium slag was produced in China in 2023, which accounted for 83% of the total disposal of magnesium slag worldwide. To explore the innovative and high-end application of MS in building materials, this study investigated the preparation of calcium carbonate cementitious composites produced by high-volume (80%) MS and 20% of traditional ordinary Portland cement (OPC), low-carbon cement–calcium sulfoaluminate cement (CSA), or green cement–alkali-activated materials after CO₂ curing. The effects of OPC, CSA, and AAM on the performance evolution of MS blends before and after carbonation curing were analyzed. The results indicated that AAM contributed to a superior initial strength (7.38 MPa) of MS composites after standard curing compared to OPC (1.18 MPa) and CSA (2.72 MPa). However, the lack of large pores (around 1000 nm) in the AAM-MS binder caused the slowest CO₂ penetration during the carbonation curing period compared to the OPC- and CSA-blended samples. Less than 3 days were required for the full carbonation of the CSA- and OPC-blended MS mortar, while 7 days were required for the AAM blends. After carbonation, the OPC-blended MS exhibited the highest strength performance of 51.58 MPa, while 21.38 MPa and 9.3 MPa were reached by the AAM- and CSA-blended MS mortars, respectively. OPC-blended MS composites exhibited the highest CO₂ uptake of 13.82% compared to the CSA (10.85%) and AAM (9.41%) samples. The leaching of Hg was slightly higher than the limit (<50 µg/L) in all MS mortars, which should be noticed in practical application. Full article

This paper presents the research results on the synthesis of rhenium catalysts MTO, Re₂O₇/Al₂O₃, and M-Re₂O₇/Al₂O₃ (where M = Ni, Ag, Co, Cu) from rhenium compounds (ammonium perrhenate, perrhenic acid, nickel(II) perrhenate, cobalt(II) perrhenate, zinc perrhenate, silver perrhenate, and copper(II) perrhenate) derived from waste materials. Methyltrioxorhenium (MTO) was obtained from silver perrhenate with a yield of over 80%, whereas when using nickel(II), cobalt(II), and zinc perrhenates, the product was contaminated with tin compounds and the yield did not exceed 17%. The Re₂O₇/Al₂O₃ and M-Re₂O₇/Al₂O₃ catalysts were obtained from the above-mentioned rhenium compounds. Alumina obtained in a calcination process of aluminum nitrate nonahydrate was used as a support. The catalysts were characterized in terms of their chemical and phase composition and physicochemical properties. Catalytic activity in model reactions, such as cyclohexene epoxidation and hex-1-ene homometathesis, was also studied. MTO obtained from silver perrhenate showed >70% activity in the epoxidation reaction, thus surpassing commercial MTO (1.0 mol% MTO, room temperature, and reaction time—2 h). Ag-Re₂O₇/Al₂O₃, Cu-Re₂O₇/Al₂O₃, and H-Re₂O₇/Al₂O₃ catalysts were inactive, while Co-Re₂O₇/Al₂O₃ and Ni-Re₂O₇/Al₂O₃ showed low activity (<43%) in the hex-1-ene homometathesis reaction. Only Re₂O₇/Al₂O₃ catalysts achieved >70% activity in this reaction (2.5 wt% Re, room temperature, and reaction time—2 h). The results indicate the potential of using rhenium compounds derived from waste materials to synthesize active catalysts for chemical processes. Full article

Circulating fluidized bed fly ash (CFBFA) stockpiles release alkaline dust, high-pH leachate, and secondary CO₂/SO₂—an environmental burden that exceeds 240 Mt yr⁻¹ in China alone. Yet, barely 25% is recycled, because the high f-CaO/SO₃ contents destabilize conventional cementitious products. Here, we presents a pressurized flue gas heat curing (FHC) route to bridge this scientific deficit, converting up to 85 wt% CFBFA into structural lightweight gravel. The gypsum dosage was optimized, and a 1:16 (gypsum/CFBFA) ratio delivered the best compromise between early ettringite nucleation and CO₂-uptake capacity, yielding the highest overall quality. The optimal mix reaches 9.13 MPa 28-day crushing strength, 4.27% in situ CO₂ uptake, 1.75 g cm⁻³ bulk density, and 3.59% water absorption. Multi-technique analyses (SEM, XRD, FTIR, TG-DTG, and MIP) show that FHC rapidly consumes expansive phases, suppresses undesirable granular-ettringite formation, and produces a dense calcite/needle-AFt skeleton. The FHC-treated CFBFA composite gravel demonstrates 30.43% higher crushing strength than JTG/TF20-2015 standards, accompanied by a water absorption rate 28.2% lower than recent studies. Its superior strength and durability highlight its potential as a low-carbon lightweight aggregate for structural engineering. A life-cycle inventory gives a cradle-to-gate energy demand of 1128 MJ t⁻¹ and a process GWP of 226 kg CO₂-eq t⁻¹. Consequently, higher point-source emissions paired with immediate mineral sequestration translate into a low overall climate footprint and eliminate the need for CFBFA landfilling. Full article

The construction sector makes a major contribution to global greenhouse gas emissions, in which cement alone produces approximately 7–8% of global CO₂ emissions. To abate environmental impact and promote sustainable construction, alternative low-carbon cementitious materials are gaining attention. Biochar (BC), a carbon-rich material obtained from biomass sources through the process of pyrolysis, has surfaced as a capable supplementary cementitious material due to its carbon capture capabilities and positive impact on the characteristics of cement composites. This review investigates the role of BC in cement composites, including its effects on hydration kinetics, microstructural development, fresh-state properties, and its optimal utilisation. The study also highlights the internal curing capabilities of BC when used in cement composites, its role in promoting hydration product formation, and its dual function in enhancing mechanical performance while facilitating carbon capture. Despite the benefits, there are some challenges such as variable BC properties, optimal dosage, and scalability. The review highlights the need for standardisation and further research to fully harness BC’s potential as a sustainable component in low-carbon construction technologies. Full article

Background: Tuberculosis (TB) remains a major global public health challenge, and diagnosing it can be difficult due to issues such as distinguishing active TB from latent TB infection (LTBI), as well as the sample collection process, which is often time-consuming and lacks sensitivity and specificity. Ferroptosis is emerging as an important factor in TB pathogenesis; however, its underlying molecular mechanisms are not fully understood. Thus, there is a critical need to establish ferroptosis-related diagnostic biomarkers for tuberculosis (TB). Methods: This study aimed to identify and validate potential ferroptosis-related genes in TB infection while enhancing clinical diagnostic accuracy through bioinformatics-driven gene identification. The microarray expression profile dataset GSE28623 from the Gene Expression Omnibus (GEO) database was used to identify ferroptosis-related differentially expressed genes (FR-DEGs) associated with TB. Subsequently, these genes were used for immune cell infiltration, Gene Set Enrichment Analysis (GSEA), functional enrichment and correlation analyses. Hub genes were identified using Weighted Gene Co-expression Network Analysis (WGCNA) and validated in independent datasets GSE37250, GSE39940, GSE19437, and GSE31348. Results: A total of 21 FR-DEGs were identified. Among them, four hub genes (ACSL1, PARP9, TLR4, and ATG3) were identified as diagnostic biomarkers. These biomarkers were enriched in immune-response related pathways and were validated. Immune cell infiltration, GSEA, functional enrichment and correlation analyses revealed that multiple immune cell types could be activated by FR-DEGs. Throughout anti-TB therapy, the expression of the four hub gene signatures significantly decreased in patients cured of TB. Conclusions: In conclusion, ferroptosis plays a key role in TB pathogenesis. These four hub gene signatures are linked with TB treatment effectiveness and show promise as biomarkers for differentiating TB from LTBI. Full article

Ionizing radiations are responsible for bond scission, radical formation, and oxidative degradation of polymer matrices. This study focuses on the effects of gamma irradiation on solid propellant binders, targeting a comprehensive chemical and mechanical characterization of different formulations. Samples were produced either by conventional methods based on hydroxyl-terminated polybutadiene and standard polyaddition reaction using isocyanates, or innovative approaches involving UV-driven radical curing. The samples were irradiated for comparison and to study their evolution as a function of three absorbed doses (25, 45, 130 kGy) for preliminary characterization studies, using a 60-Co gamma source. Samples were irradiated in air at uncontrolled room temperature. The coupling of spectroscopy techniques (Fourier transform infrared—FTIR, Raman and electron paramagnetic resonance—EPR) and dynamic mechanical analysis (DMA) highlighted the key role of antioxidant agents in tailoring mechanical changes in the binder phase. The absence of antioxidants enhances radical formation, oxidation, and cross-linking. These processes lead to progressively increased rigidity and reduced flexibility as a function of the absorbed dose. Complex interactions between photocured components largely influence radical stabilization and material degradation. These findings provide valuable insights for designing novel radiation-resistant binders, enabling the development of solid propellants tailored for reliable, long-term permanence in space, and advancing the knowledge on the applicability of 3D-printed propellants. Full article

Soil stabilizers are environmentally friendly engineering materials that enable efficient utilization of local soil-water resources. The application of nano-modified stabilizers to reinforce loess can effectively enhance the microscopic interfacial structure and improve the macroscopic mechanical properties of soil. This study employed nano-SiO₂ and nano-CaCO₃ to modify cement-based soil stabilizers, investigating the enhancement mechanisms of nanomaterials on stabilizer performance through compressive and flexural strength tests combined with microscopic analyses, including SEM, XRD, and FT-IR. The key findings are as follows: (1) Comparative analysis of mortar specimen strength under identical conditions revealed that nano-SiO₂ generally demonstrated superior mechanical enhancement compared to nano-CaCO₃ across various curing ages (1–3% dosage). At 1% dosage, the compressive strength of both modified stabilizers increased with curing duration. Early-stage strength differences (3 days) remained below 3% but showed a significant divergence with prolonged curing: nano-SiO₂ groups exhibited 10.3%, 11.3%, and 7.2% higher compressive strengths than nano-CaCO₃ at 7, 14, and 28 days, respectively. (2) The strength enhancement effect of nano-SiO₂ on MBER soil stabilizer followed a parabolic trend within 1–3% dosage range, peaking at 2.5% with over 15% strength improvement. (3) The exceptional performance of nano-SiO₂ originates from its high reactivity and ultrafine particle characteristics, which induce nano-catalytic hydration effects and demonstrate strong pozzolanic activity. These properties accelerate hydration processes while promoting the formation of interlocking C-S-H gels and hexagonal prismatic AFt crystals, ultimately creating a robust three-dimensional network that optimizes interfacial structure and significantly enhances strength characteristics across curing periods. These findings provide scientific support for the performance optimization of soil stabilizers and their sustainable applications in eco-construction practices. Full article

Adaptor protein (AP) complexes are critical components of the cellular membrane transport machinery. They mediate cargo selection during endocytosis and intracellular vesicular trafficking. Five AP complexes have been characterized (AP1-5), and together their roles extend to diverse cellular processes including the homeostasis of membranous organelles, membrane protein turnover, and immune responses. Human Immunodeficiency Virus type 1 (HIV-1) and other lentiviruses co-opt these complexes to support immune evasion and the assembly of maximally infectious particles. HIV-1 Nef interacts with AP1 and AP2 to manipulate intracellular trafficking and downregulate immune-related proteins such as CD4 and MHC-I. Vpu also co-opts AP1 and AP2, modulating the innate defense protein BST2 (Tetherin) and facilitating the release of virions from infected cells. The envelope glycoprotein (Env) hijacks AP complexes to reduce its expression at the cell surface and potentially support incorporation into virus particles. Some data suggest that Gag co-opts AP3 to drive assembly at intracellular compartments. In principle, targeting the molecular interfaces between HIV-1 proteins and AP complexes is a promising therapeutic approach. Blocking these interactions should impair HIV-1’s ability to produce infectious particles and evade immune defenses, leading to novel antivirals and facilitating a cure. Full article

Calcium lignosulfonate was incorporated into rubber compounds based on styrene–butadiene rubber (SBR) and acrylonitrile–butadiene rubber (NBR) in amounts ranging from 10 to 60 phr. A sulfur-based curing system and a peroxide curing system consisting of dicumyl peroxide in combination with methacrylic acid zinc salt were used for cross-linking of the compounds. The aim of the work was to investigate the influence of lignosulfonate and curing system composition of the cross-linking process, morphology, physical–mechanical and dynamic–mechanical characteristics of the composites. The achieved results showed that peroxide cured composites demonstrated higher cross-link density, which was found not to be influenced by the content of lignosulfonate. The cross-link density of sulfur-cured composites was lower and showed a decreasing tendency with increasing amounts of the biopolymer. A lower cross-linking degree was reflected in a higher elongation at break and higher increase in the elongation at break of the corresponding composites. On the other hand, peroxide-cured composites exhibited a higher modulus M100 and higher hardness. The microscopic analysis revealed that co-agent in peroxide vulcanization contributed to the improvement of adhesion between the biopolymer and the rubber resulting in higher tensile strength of the equivalent composites. The higher cross-link density of peroxide-cured composites caused higher restriction of the chain segments’ mobility, due to which these composites exhibited a higher glass transition temperature. Full article

Living systems require energy to maintain their existence and perform tasks such as cell division. This energy is stored in several molecular forms in nature, specifically lipids, carbohydrates, and amino acids. At a cellular level, energy is extracted from these complex molecules and transferred to adenosine triphosphate (ATP) in the cytoplasm and mitochondria. Within the mitochondria, fatty acid β-oxidation (FAO) and oxidative phosphorylation (OXPHOS) are crucial metabolic processes involved in generating ATP, with defects in these pathways causing mitochondrial disease. Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) is a fatty acid β-oxidation disorder (FAOD) affecting 1 to 2 individuals per 100,000. Similar to other mitochondrial disorders, there is no cure for VLCADD, with symptomatic treatment comprising dietary management and supplementation with medium-chain fatty acids to bypass the enzyme deficiency. While this addresses the primary defect in VLCADD, there is growing evidence that other aspects of mitochondrial function are also affected in VLCADD, including secondary defects in OXPHOS function. Here, we review our current understanding of VLCADD with a focus on the associated biochemical and molecular defects that can disrupt multiple aspects of mitochondrial function. We describe the interactions between FAO proteins and the OXPHOS complexes and how these interactions are critical for maintaining the activity of both metabolic pathways. In particular, we describe what is now known about the protein–protein interactions between VLCAD and the OXPHOS supercomplex and how their disruption contributes to overall VLCADD pathogenesis. Full article