Search Results (213)

Developing sustainable and molecularly selective adsorbents for heavy-metal removal remains a critical challenge in water purification. Herein, we report a green molecular-engineering approach for fabricating aza-crown ether functionalized sodium alginate aerogels (ACSA) capable of highly selective Cu²⁺ capture. The aerogels were synthesized via saccharide-ring oxidation, Cu²⁺-templated self-assembly, and reductive amination, enabling the covalent integration of aza-crown ether motifs within a hierarchically porous biopolymer matrix. Structural analyses (FTIR, ¹³C NMR, XPS, SEM, TGA) confirmed the in situ formation of macrocyclic N/O coordination sites. Owing to their interconnected porosity and chemically stable framework, ACSA exhibited rapid sorption kinetics following a pseudo-second-order model (R² = 0.999) and a Langmuir maximum adsorption capacity of 150.82 mg·g⁻¹. The material displayed remarkable Cu²⁺ selectivity over Zn²⁺, Cd²⁺, and Ni²⁺, arising from the precise alignment between Cu²⁺ ionic radius (0.73 Å) and crown-cavity dimensions, synergistic N/O chelation, and Jahn-Teller stabilization. Over four regeneration cycles, ACSA retained more than 80% of its original adsorption capacity, confirming excellent durability and reusability. This saccharide-ring modification strategy eliminates crown-ether leaching and weak anchoring, offering a scalable and environmentally benign route to bio-based adsorbents that combine molecular recognition with structural stability for efficient Cu²⁺ remediation and beyond. Full article

Low-temperature plasma treatments were applied to barley seeds using a dielectric barrier-stabilized corona discharge operated in ambient air enriched with oxygen or nitrogen to quantify surface chemical modifications and seed wettability. X-ray photoelectron spectroscopy showed that oxygen-enriched plasma produced the strongest oxidation, increasing surface oxygen from 9 ± 5 at% (control) to 24 ± 5 at%, while reducing carbon from 88 ± 5 at% to 76 ± 5 at%. Nitrogen-enriched plasma induced more moderate changes (O: 13 ± 5 at%, C: 85 ± 5 at%) but resulted in clear nitrogen incorporation, with an enhanced N 1s amine/amide component at ~400.8 eV. The hydroxyl O 1s contribution increased from 70% (control) to 82% (oxygen) and 90% (nitrogen), indicating substantial surface hydroxylation. SEM-EDX showed only minor micrometer-scale composition changes and no detectable morphological damage. Raman and ATR-FTIR spectra confirmed that polysaccharide, protein, and lipid structures remained intact, with intensity variations reflecting increased hydrophilicity. Water imbibition kinetics fitted with the Peleg model demonstrated faster initial hydration after plasma exposure, with 1/k₁ increasing from 20.25 ± 1.90 h⁻¹ (control) to 36.70 ± 6.56 h⁻¹ (oxygen) and 38.87 ± 7.57 h⁻¹ (nitrogen), while 1/k₂ remained nearly unchanged. Full article

Carbon dioxide (CO₂) is the most significant anthropogenic greenhouse gas (GHG), accounting for approximately 81% of total emissions, with methane (CH₄), nitrous oxide (N₂O), and fluorinated gases contributing the remainder. Rising atmospheric CO₂ concentrations, driven primarily by fossil fuel combustion, industrial processes, and transportation, have surpassed the Earth’s natural sequestration capacity, intensifying climate change impacts. Carbon Capture, Utilization, and Storage (CCUS) offers a portfolio of solutions to mitigate these emissions, encompassing pre-combustion, post-combustion, oxy-fuel combustion, and direct air capture (DAC) technologies. This review synthesizes advancements in CO₂ capture materials including liquid absorbents (amines, amino acids, ionic liquids, hydroxides/carbonates), solid adsorbents (metal–organic frameworks, zeolites, carbon-based materials, metal oxides), hybrid sorbents, and emerging hydrogel-based systems and their integration with utilization and storage routes. Special emphasis is given to CO₂ mineralization using mine tailings, steel slag, fly ash, and bauxite residue, as well as biological mineralization employing carbonic anhydrase (CA) immobilized in hydrogels. The techno-economic performance of these pathways is compared, highlighting that while high-capacity sorbents offer scalability, hydrogels and biomineralization excel in low-temperature regeneration and integration with waste valorization. Challenges remain in cost reduction, material stability under industrial flue gas conditions, and integration with renewable energy systems. The review concludes that hybrid, cross-technology CCUS configurations combining complementary capture, utilization, and storage strategies will be essential to meeting 2030 and 2050 climate targets. Full article

Flow capacitive deionization (FCDI) technology holds significant promise for cost-effective and energy-efficient desalination; however, its practical application is hindered by limited electrode stability and desalination performance. In this study, we propose a novel composite strategy that combines chemical surface modification with surfactant-assisted dispersion to enhance electrode performance in FCDI systems. We observed that the dispersion stability and capacitance of the flow electrodes were significantly improved after oxidation (AC-O) or amination (AC-N) of activated carbon (AC). To further investigate the underlying ion adsorption mechanisms, we performed Density Functional Theory (DFT) simulations. The simulations revealed that oxidative modification (AC-O) enhances chloride ion adsorption through stronger electrostatic and van der Waals interactions, while amination (AC-N) is more effective for sodium ion adsorption. Subsequently, surfactants (sodium dodecyl sulfate, SDS; cetyltrimethylammonium bromide, CTAB) were used to prepare stable and high-performance flow electrodes. Electrochemical characterization and desalination tests in a 1000 mg·L⁻¹ saline solution demonstrated that the AC-O/SDS composite exhibited excellent dispersion stability (>7 d) and significantly enhanced conductivity and specific capacitance, increasing by factors of 2.48 and 2.50, respectively, compared to unmodified AC. This optimized electrode achieved a desalination efficiency of 74.37% and a desalination rate of 6.2542 mg·L⁻¹·min⁻¹, outperforming the unmodified electrode by a factor of 5.72. Our findings provide a robust, sustainable approach for fabricating advanced flow electrodes and offer valuable insights into electrode structure optimization, opening new possibilities for the application of FCDI technology in water treatment and material sciences. Full article

Background/Objectives: Linezolid is a first-in-class oxazolidinone antibiotic that exhibits activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. However, its clinical use is often restricted because of hematological toxicities, particularly thrombocytopenia, in patients with renal impairment. That side effect is thought to result from the systemic accumulation of pharmacologically inactive metabolites generated by oxidative degradation and ring-opening of the morpholine, but the details remain unclear. In this study, we established a novel synthetic route for four linezolid metabolites (PNU-142618, 142300, 142586 and 173558). Methods: The four major metabolites, which are secondary or tertiary amines, were synthesized using the aniline derivatives protected with a 2-nitrobenzensulfonyl (Ns) group. Results: Application of this Ns strategy enabled selective N-alkylation, enabling efficient synthesis of the target metabolites. The desired metabolites containing a carboxylic acid group were obtained as their sodium salts. This is the first report on the synthesis of PNU-142618 and 173558. Conclusions: The established synthetic pathway provides access to four linezolid metabolites. The results facilitated the provision of compounds necessary for comprehensive pharmacokinetic and toxicological studies. Full article

Meat products are popularized worldwide for their great flavor and high nutritional value. However, a high consumption of high-temperature processed meat has posed an adverse health implication, contributing to an imperative demand for healthier meat products. Polyphenols are a category of compounds with excellent antioxidant and antimicrobial properties. Accumulating evidence has demonstrated that polyphenols can reduce carcinogen formation, particularly heterocyclic aromatic amines (HAAs), polycyclic aromatic hydrocarbons (PAHs), and N-nitrosamines (NAs), during thermal processing of meat. Notably, polyphenols can mitigate lipid and protein oxidation during the gastrointestinal digestion of meat, underscoring the role of antioxidant polyphenols in enhancing meat consumption safety. To promote the application of polyphenols in mitigating hazardous compounds in meat products, this review elucidates polyphenols’ mitigation mechanisms against thermally generated carcinogens in meat products, analyzing their multilevel suppression pathways during processing and subsequent digestive transformation through gastrointestinal interfaces. Furthermore, this article proposes an encapsulation strategy for polyphenols to address their inherent low aqueous solubility and detrimental effects on sensory properties in meat products, aiming to enhance bioavailability while minimizing adverse organoleptic impacts. This review can provide new strategies for the application of polyphenols in developing healthier meat products and to indicate a feasible direction for future research. Full article

Nanotechnology offers powerful new tools to enhance food quality monitoring and safety assurance. In the food industry, nanoscale materials (e.g., metal, metal oxide, carbon, and polymeric nanomaterials) are being integrated into sensory systems to detect spoilage, contamination, and intentional food tampering with unprecedented sensitivity. Nanosensors can rapidly identify foodborne pathogens, toxins, and chemical changes that signal spoilage, overcoming the limitations of conventional assays that are often slow, costly, or require expert operation. These advances translate into improved food safety and extended shelf-life by allowing early intervention (for example, via antimicrobial nano-coatings) to prevent spoilage. This review provides a comprehensive overview of the types of nanomaterials used in food sensory applications and their mechanisms of action. We examine current applications in detecting food spoilage indicators and adulterants, as well as recent innovations in smart packaging and continuous freshness monitoring. The advantages of nanomaterials—including heightened analytical sensitivity, specificity, and the ability to combine sensing with active preservative functions—are highlighted alongside important toxicological and regulatory considerations. Overall, nanomaterials are driving the development of smarter food packaging and sensor systems that promise safer foods, reduced waste, and empowered consumers. However, realizing this potential will require addressing safety concerns and establishing clear regulations to ensure responsible deployment of nano-enabled food sensing technologies. Representative figures of merit include Au/AgNP melamine tests with LOD 0.04–0.07 mg L⁻¹ and minute-scale readout, a smartphone Au@carbon-QD assay with LOD 3.6 nM, Fe₃O₄/DPV detection of Sudan I at 0.001 µM (linear 0.01–20 µM), and a reusable Au–Fe₃O₄ piezo-electrochemical immunosensor for aflatoxin B1 with LOD 0.07 ng mL⁻¹ (≈15 × reuse), alongside freshness labels that track TVB-N/amine in near-real time and e-nose arrays distinguishing spoilage stages. Full article

The photoinitiation properties of two porphyrins were evaluated for the free-radical photopolymerization (FRP) of a bio-based acrylated monomer, i.e., soybean oil acrylate (SOA). Their combination with various co-initiators, such as a tertiary amine as electron donor (MDEA), an iodonium salt as electron acceptor (Iod), as well as two biosourced co-initiators used as H-donors (cysteamine and N-acetylcysteine), makes them highly efficient photoinitiating systems for FRP under visible light irradiation. Electron paramagnetic resonance spin trapping (EPR ST) demonstrated the formation of highly reactive radical species, and fluorescence and laser flash photolysis highlighted the chemical pathways followed by the porphyrin-based systems under light irradiation. High acrylate conversions up to 96% were obtained with these different systems at different irradiation wavelengths (LEDs@385 nm, 405 nm, 455 nm, and 530 nm), in laminate or under air. The final crosslinked and bio-based porphyrin-based materials were used for the full photo-oxidation in water of an azo-dye (acid red 14) and under UV irradiation. These materials have been involved in three successive depollution cycles without any reduction in their efficiency. Full article

Citrus peels, long used in traditional food preservation, are rich in bioactive compounds with potential antioxidant and antimicrobial properties. However, a systematic comparison of the efficacy of different citrus varieties and the underlying mechanisms in meat preservation remains limited. This study investigated the chemical composition of peels from four citrus varieties (Citrus reticulata, CR; C. sinensis, CS; C. bigarradia, CB; and C. macrocarpa, CM) and their efficacy in preserving beef quality during refrigerated storage. GC-MS analysis revealed limonene as the predominant volatile component (59.6~77.1%), with CR peel exhibiting the highest content (77.1%). CR extract also demonstrated superior antioxidant activity (DPPH: 60.8%; ABTS: 66.0%) and antimicrobial effects against five common meat microbial species. Beef samples treated with CR peel extract significantly (p < 0.05) reduced lipid oxidation (TBARS: 2.88 vs. 4.83 mg MDA/kg in control) and protein degradation (TVB-N: 270 vs. 371 mg/kg). Microstructural integrity was better maintained, as evidenced by lower surface hydrophobicity, higher sulfhydryl content, and reduced carbonyl formation. Furthermore, CR treatment suppressed microbial growth (TBC and TAC reduced by ~30%) and the accumulation of spoilage-related biogenic amines, particularly putrescine (12~18.8 vs. 27.4 mg/kg). Correlation analysis identified limonene content as strongly correlated with antioxidant and antimicrobial activities. This work validates the scientific basis of using citrus peel, particularly CR, as a natural preservative, effectively bridging traditional culinary practice with modern food science by elucidating its multi-target role in extending the shelf life and enhancing the safety of beef. Full article

This work evaluates the CO₂-adsorption relevance and cycling stability of graphene oxide–silica (GO-SiO₂) and reduced graphene oxide–silica (rGO-SiO₂) gels after amine functionalization, demonstrating high-capacity retention under repeated adsorption–desorption cycles: rGO-SiO₂-APTMS retains ≈96.3% of its initial uptake after 50 cycles, while GO-SiO₂-APTMS retains ≈90.0%. The use of surfactants to control the organization of inorganic and organic molecules has enabled the development of ordered mesostructures, such as mesoporous silica and organic/inorganic nanocomposites. Owing to the outstanding properties of graphene and its derivatives, synthesizing mesostructures intercalated between graphene sheets offers nanocomposites with novel morphologies and enhanced functionalities. In this study, GO-SiO₂ and rGO-SiO₂ gels were synthesized and characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), mass spectrometry (MS), N₂ adsorption–desorption isotherms, and transmission electron microscopy (TEM). The resulting materials exhibit a laminar architecture, with mesoporous silica domains grown between graphene-based layers; the silica contents are 83.6% and 87.6%, and the specific surface areas reach 446 and 710 m²·g⁻¹, respectively. The laminar architecture is retained regardless of the surfactant-removal route; however, in GO-SiO₂ obtained by solvent extraction, a fraction of the surfactant remains partially trapped. Together with their high surface area, hierarchical porosity, and amenability to surface functionalization, these features establish amine-grafted graphene–silica gels, particularly rGO-SiO₂-APTMS, as promising CO₂-capture adsorbents. Full article

Reductive amination of cyclohexanone with NH₃ and H₂ over Rh and Rh-Ni catalysts on SiO₂ has been studied. Research has focused on the catalytic efficiency of monometallic and bimetallic catalysts in the production of cyclohexylamine, a key intermediate in the synthesis of numerous fine chemicals. Through the wet impregnation method, Rh and Rh-Ni catalysts with varying nickel loadings (1, 2, 5, and 10 wt.%) were synthesized and characterized using techniques such as N₂ physisorption, TEM, HAADF-STEM, XRD, XPS, H₂-TPR, and NH₃-TPD. The catalytic reactions were conducted under controlled conditions using a glass-coated reactor, using ammonia as nitrogen source. Rh-Ni bimetallic catalysts exhibited the highest conversion rates on reductive amination, attributed to enhanced dispersion and advantageous surface properties. High metal dispersion and small particle sizes were confirmed by TEM, HAADF-STEM, and XRD. XPS analysis confirmed the reduced state of Rh and mainly oxidized state of Ni, while H₂-TPR and NH₃-TPD results indicated improved reducibility and acidity, respectively, which are critical for catalytic activity. Monometallic Rh/SiO₂ catalyst showed 83.4% of conversion after 300 min and selectivity of 99.1% toward the desired product cyclohexylamine. The addition of nickel, a cheap and easily available metal, increases the activity without compromising selectivity. At 300 min of the reaction, the 2 wt.% NiRh/SiO₂ catalyst exhibited the highest conversion, yield, and selectivity for the desired product cyclohexylamine, 99.8%, 96.4%, and 96.6% respectively. Additionally, this catalyst is recyclable after the fourth cycle, showing 99.5% selectivity and 74.0% yield for cyclohexylamine at 75.7% conversion. Recycling tests confirmed the stability of bimetallic catalysts, maintaining performance over multiple cycles without significant deactivation. Full article

Background/Objectives: Gut microbial metabolism of choline and related quaternary amines to trimethylamine (TMA) is the first step in the production of trimethylamine N-oxide (TMAO), a circulating metabolite that contributes to the development of atherosclerosis and other forms of cardiovascular disease (CVD). No data exist on regional differences in TMA production within the colon due to difficulties studying gut regions in vivo. A better understanding of TMA production by gut microbiota is needed to develop strategies to limit TMA production in the gut and TMAO levels in circulation with the goal of reducing CVD risk. Methods: We employed our novel three-compartment MiGut in vitro model, which establishes three distinct microbial ecologies mimicking the proximal, mid, and distal colon, to study conversion of choline to TMA by human gut microbiota using isotopically labelled substrate. Results: Choline-d₉ was almost completely converted to TMA-d₉ in vessels 2–3 (mimicking the mid and distal colon) within 6–8 h, but little conversion occurred in vessel 1 (mimicking the proximal colon). Abundance of cutC, part of the cutC/D gene cluster responsible for choline conversion to TMA, was highest in vessel 1 vs. 2–3, suggesting that its expression or activity may be suppressed in the proximal colon. Another possibility is that the viability/activity of bacteria expressing cutC could be suppressed in the same region. Conclusions: This novel finding suggests that while bacteria capable of converting choline to TMA exist throughout the colon, their activity may be different in distinct colon regions. The regional specificity of TMA production, if confirmed in vivo, has implications for both basic microbial ecology related to CVD and the development of strategies to control TMA and TMAO production, with the goal of lowering CVD risk. These findings warrant further study in vitro and in vivo. Full article

Trimethylamine N-oxide (TMAO) is known to increase in human cardiovascular, metabolic, and renal diseases. In human medicine, TMAO has recently been utilized as a diagnostic and prognostic biomarker for renal dysfunction, and research is ongoing regarding its potential as a therapeutic target. This study aimed to evaluate the diagnostic and prognostic potential of TMAO as a supportive biomarker in dogs with chronic kidney disease (CKD). To assess its diagnostic utility, TMAO concentrations were compared between a CKD group (n = 32) and a healthy control group (n = 32). In addition, patients with CKD were subdivided into stages 2 (n = 12), 3 (n = 11), and 4 (n = 9) and compared individually with the healthy controls. For prognostic evaluation, the CKD group was monitored over six months, and the TMAO levels were compared between survivors (n = 18) and non-survivors (n = 14). The TMAO concentrations showed a highly significant difference between patients with CKD and healthy controls (p < 0.0001). Patients with each different CKD stage exhibited statistically significant differences compared with the healthy controls (p < 0.05). Furthermore, the median TMAO levels tended to increase with advancing CKD stage; however, the differences among stages were not statistically significant. In addition, within the CKD group, TMAO concentrations were significantly higher in non-survivors than in survivors at the six-month follow-up (p = 0.0142). This pilot study highlights the potential of TMAO as a supportive renal biomarker for diagnostic and prognostic evaluation in canine CKD. Full article

Tertiary amine oxide (TAO)-containing zwitterionic polymers are a class of zwitterionic materials formed by the oxidation of tertiary amine groups. In recent years, polymers such as poly(2-(N-oxide-N,N-diethylamino)ethyl methacrylate) (OPDEA) have gained significant attention due to their unique antifouling properties, dynamic cell membrane affinity, and responsiveness to microenvironments. These characteristics have made them promising candidates in drug delivery, antibiofouling, and precision therapy. Compared to traditional polyethylene glycol (PEG), these polymers not only exhibit long-circulation properties but can also overcome biological barriers through active transport mechanisms, making them a research hotspot in the field of next-generation biomaterials. This review comprehensively summarizes the recent advancements in this field, covering aspects such as the synthesis, properties, applications, and mechanisms of TAO-containing zwitterionic polymers. Full article

The safety concerns associated with sensitivity issues regarding long nitrogen chain-based energetic compounds, especially for eight or more catenated nitrogen atoms in backbones, need to be resolved. Incorporating specific functional groups represents a key approach for enhancing stability in organic energetic materials. This study reports the synthesis of 1,1′-(diazene-1,2-diyl)bis(4-nitro-1H-1,2,3-triazole-5-carboxamide) (S8), an N8-chain compound featuring strategically placed amide groups. Employing THA(O-tosylhydroxylamine) and KMnO₄, 1,1′-(diazene-1,2-diyl)bis(4-nitro-1H-1,2,3-triazole-5-carboxamide) (S8) was synthesized and underwent N-amination and oxidative azo coupling. Comprehensive characterization, including X-ray diffraction, mechanical sensitivity testing, and theoretical analysis, alongside comparative studies with known N8 compounds, revealed that S8 exhibits unprecedented stability within its class. Among reported N8-catenated nitrogen chain compounds, attributed to the incorporation of the amide functionality, S8 demonstrates the highest impact sensitivity (IS = 10 J) and friction sensitivity (FS = 40 N) while maintaining excellent detonation performance (D = 8317 ms⁻¹, P = 28.27 GPa). This work highlights the amide group as a critical structural part for achieving high stability in sensitive long-nitrogen-chain energetic materials without compromising performance. Full article