Structure-dependent transformation of cephalosporin antibiotics at MnO2 surface mediated by iodide and formation of highly toxic iodinated products.

Epigallocatechin-3- O -gallate (EGCG), the principal bioactive component of green tea, exhibits diverse biological activities, particularly antioxidant effects that contribute to its therapeutic potential. However, EGCG undergoes autoxidation under physiological conditions, leading to the formation of reactive oxygen species (ROS) and decomposition. This process results in poor chemical stability, limited bioavailability and potential cytotoxicity, thereby limiting its biomedical utility. To overcome these drawbacks, herein, EGCG was covalently conjugated to poly(ethylene glycol) (PEG), a hydrophilic and biocompatible polymer. The resulting conjugate (PEG–EGCG) effectively suppressed autoxidation and ROS formation, while enhancing cytocompatibility compared to native EGCG. Moreover, the conjugates spontaneously self-assembled into nanomicelles in aqueous environments, which may contribute to improved physicochemical stability. Importantly, PEG–EGCG maintained effective radical-scavenging activity in both acellular and cellular systems, supporting preservation of its antioxidant functionality. These findings highlight PEG conjugation as a promising strategy to stabilize EGCG and improve its biological performance for antioxidant-related biomedical applications. • EGCG was conjugated to PEG, preserving phenolic hydroxyl groups for bioactivities. • PEG conjugation enabled spontaneous self-assembly into nanomicelles. • PEG–EGCG suppressed autoxidation-associated ROS generation and cytotoxicity. • PEG–EGCG preserved antioxidant properties in both acellular and cellular systems.

Photochemical dissolution of bismuth vanadate and formation of volatile bismuth species: Effects of low-molecular-weight organic acids and chloride ions

A review of perovskite catalysts for automotive exhaust soot conversion: Structure, activity and design strategies

Effective PFAS degradation in aquatic systems: Performance evaluation and mechanistic drivers of peroxydisulfate activation by thermal energy

Novel insights into skyrin action in cancer cells.

• Synthesized Pt/CeO₂ scavenger to neutralize radicals and increase fuel cell durability. • The "intermixed" method is most effective for adding scavenger to the catalyst layer. • Optimal scavenger loading in the cathodic catalyst layer was identified as 1.0 wt.%. • Achieved max power density of ∼950 mW/cm² at 80°C and 50% relative humidity. • ADT shows a 19% performance loss of MEA containing scavenger versus 35% for the reference system after 48 hours. Polymer Electrolyte Fuel Cells (PEFCs) are a promising technology for clean energy conversion, but their long-term performance is often limited by fuel crossover, electrode degradation, and reactive species formation. In this study, the incorporation of radical scavengers into the cathodic catalyst layer (CL) was investigated as a strategy to enhance PEFC durability and performance. Different incorporation methods were tested, and the optimal scavenger loading was determined (0.5–1.5 wt.%). Membrane Electrode Assemblies (MEAs) in Catalyst Coated Membrane (CCM) configuration were electrochemically characterized in single-cell setups. Results show that the “intermixed” method—adding the scavenger directly to the catalyst ink—provides the most effective performance enhancement. The optimal loading of 1 wt.% resulted in a maximum power density of approximately 950 mW/cm² at 80 °C and 50% RH. Accelerated stress tests under open-circuit voltage conditions demonstrated significantly improved stability: at 0.5 A/cm², the scavenger-based MEA lost only 19% of its initial performance, compared to 35% for the reference MEA. These findings demonstrate that incorporating an optimized amount of radical scavenger into the cathodic CL effectively enhances both the performance and long-term durability of PEFCs.

Phylogenomics of the woodland salamanders (Plethodon): Reticulate evolution and indistinct species boundaries.

Structural dynamics of chloroplast genome in Paphiopedilum (Orchidaceae): in response to natural hybridization.

The formation of RIP-homotypic interaction motif (RHIM)-based heteromeric amyloid assemblies between effector proteins such as receptor-interacting protein kinases 1, Z-DNA Binding Protein 1, or TRIF and the kinase RIPK3 serves as regulating signals for the necroptosis process, a key element of innate immune defense. Murine cytomegalovirus expresses the M45-encoded viral inhibitor of RIP activation which inhibits necroptosis in a RHIM-dependent manner. A pivotal question is how viral M45 forms heteroamyloids with RIPK3 to effectively create an inhibitory assembly. We report a high-resolution structure of the M45:RIPK3 complex where M45 and RIPK3 alternately stack in an amyloid-state structure. Mutagenesis of the residues flanking the IQIG tetrad in M45 results in specific impacts on coassembly with RIPK3, indicating an extended interface in the heteromeric fibrils. Other key interactions support the formation of stable viral:host fibrils. The M45:RIPK3 heteroamyloid is likely to act as an antinecroptotic signal by competing with formation of other pronecroptotic species and introducing a barrier to RIPK3 autophosphorylation.

Biological differences between sexes—particularly due to fluctuating levels of 17β-estradiol and menstrual cycle dynamics—may influence exercise-induced reactive oxygen species (ROS) formation, inflammation and exercise performance. Despite these considerations, there is a lack of research exploring how estradiol and menstrual cycle phases may impact exercise performance, exercise-induced ROS formation and inflammation. This study aimed to examine whether estradiol concentration or menstrual cycle phase may be significantly associated with resistance circuit high-intensity interval training (HIIT) performance, as well as exercise-induced formation of ROS and Interleukin-6 (IL-6). A total of 30 young healthy female participants completed a single bout of resistance-based HIIT in a fasted state. Blood samples were collected at four time points: at baseline after overnight fasting, two hours after consumption of 0.5 L of water (pre-HIIT), immediately post exercise (post-HIIT) and after 15 min of recovery (15-post-HIIT). Additionally, participants attended six fasting baseline assessments scheduled across various menstrual cycle days. These sessions enabled the assessment of estradiol, ROS and IL-6 concentrations throughout the menstrual cycle without being confounded by nutritional factors. Neither baseline levels of ROS nor IL-6 differed significantly between menstrual cycle phases (luteal vs. follicular ROS: 0.013 µmol/min, p = 0.716; IL-6: 0.052, p = 0.679) menstruation status (yes vs. no ROS: −0.056 µmol/min, p = 0.259; IL-6: −0.302 pg/mL, p = 0.088) or 17β-estradiol concentrations (low (11–≤72.5 pg/mL) vs. high (>72.5–394 pg/mL) ROS: −0.038 µmol/min, p = 0.266; IL-6: +0.015 pg/mL, p = 0.906). On the resistance-circuit-HIIT intervention day, no significant differences in ROS or IL-6 were observed between estradiol concentrations (ROS: p = 0.477; IL-6: p = 0.249), menstrual cycle phase (ROS; p = 0.752; IL-6: p = 0.557) or menstruation status (ROS: p = 0.383; IL-6: p = 0.808) from baseline to pre-HIIT, post-HIIT or 15-post-HIIT. These findings should be interpreted with caution, as the menstrual cycle phases were assigned using a calendar-based approach without biochemical ovulation confirmation and the subgroup sizes were relatively small. These findings suggest that natural 17-beta-Estradiol fluctuations within the menstrual cycle, as well as differences in the menstrual cycle itself, may not substantially modulate ROS or IL-6 responses to acute resistance-based HIIT in young healthy female adults.

How do new species arise? Usually, scientists explain this by showing how different habitats encourage different behaviors, including who mates with whom, eventually leading to separate species. Here, we suggest a complementary “from the inside” view. According to receiver-first evolution, inherited differences in the senses cause individuals to experience the very same environment in different ways. A small change in how the senses sense the world can create a new way of experiencing it, may modify food searching and mate choice, may lead to the formation of new species, and even change the environment through behavior. Such changes can speed up evolutionary processes and shape biodiversity. For example, the evolution of red color vision in our primate ancestors probably began with genetic changes in light receptors in the eyes. These changes may have led to a preference for red fruits, spreading more seeds, possibly slowly changing forests, and eventually affecting human evolution.

Copper model complexes that mimic metalloenzyme active sites provide important insight into copper‐mediated oxygen activation. Among the ligand frameworks explored, tripodal tetradentate nitrogen–donor ligands based on the tris(2‐aminoethyl)amine (tren) scaffold proved particularly effective at stabilizing reactive copper–oxygen intermediates. Here, we report the synthesis and characterization of new arylated tren derivatives and their coordination to Cu(I) and Cu(II) centers. The reactivity of the resulting complexes toward dioxygen (O 2 ), hydrogen peroxide (H 2 O 2 ), and cumene hydroperoxide was investigated, and transient copper–oxygen species were examined using low‐temperature stopped‐flow techniques. Superoxido intermediates were detected when electron‐donating and sterically hindered ligands were employed. Hydroperoxido species were generated through reactions of the copper complexes with both O 2 and H 2 O 2 , while treatment with cumene hydroperoxide led to the formation of alkylperoxido species. The reactivity of the peroxide species was evaluated toward external substrates. All the complexes exhibited reactivity toward benzoyl chloride, whereas efficient aldehyde deformylation was observed exclusively for the cumylperoxido species.

Silver diamine fluoride (SDF) is widely used in pediatric dentistry for caries arrest; however, concerns exist regarding its cytotoxicity. Green-synthesized nano-silver fluoride (NSF) is a potential alternative to SDF, offering antimicrobial efficacy with improved biocompatibility. This study aimed to evaluate the in vitro safety profile of green-synthesized NSF with 5% (w/v) fluoride using Camellia sinensis extract and to compare it with 38% SDF + potassium iodide (KI) formulation in human gingival fibroblasts (HGFs). Eluates of NSF and SDF+KI were tested at serial concentrations of 5%, 1%, 0.1%, 0.01% and 0.005%. Cell viability was assessed after 24, 48, and 72 h using the MTT assay. Additionally, the formation of reactive oxygen species (ROS) in HGFs was detected through fluorescence microscopy. Exposure to 5% SDF+KI resulted in almost complete loss of cell viability at all time points, whereas NSF demonstrated significantly higher viability under the same conditions. Lower concentrations of both materials maintained acceptable biocompatibility. ROS analysis revealed increased oxidative stress in response to 5% SDF+KI, while NSF induced significantly lower ROS levels. NSF exhibited superior biocompatibility compared to SDF+KI, supporting its potential as a safer silver-based material for caries management. Further in vitro and in vivo studies are needed to confirm its clinical safety profile.

Zr-/Ce-/Sm-containing intermetallic compounds, specifically ZrZnNi4, CeNi5, CeAlNi4, CeNi4Si, Ce(NiSi)2, SmNi3, SmNi4Si, and Sm(NiSi)2, were synthesized by reducing the metal oxides using a CaH2 reducing agent within molten LiCl. The resultant nanopowders exhibited high specific surface areas: ZrZnNi4 (42.0 m2 g-1), CeAlNi4 (66.9 m2 g-1), and Sm(NiSi)2 (25.0 m2 g-1). They were subsequently tested for their effectiveness in the NaBH4-assisted hydrogenation of 4-nitrophenol. When compared to the prepared catalysts, including a conventional CeO2-supported Ni catalyst, ZrZnNi4 demonstrated the highest catalytic activity. Based on experimental results and density functional theory calculations, it was proposed that enhanced performance could be attributed to the formation of electron-rich Ni species in ZrZnNi4.

Functionalized N-heterocycles are found among a majority of pharmaceutical drugs, including targeted protein degraders like cereblon E3-ligase modulating drugs (CELMoDs) that often employ the glutarimide motif. Typical strategies for synthesizing these scaffolds require individualized and multistep routes from a glutamate/glutamine derivative. In contrast, alkylation with a simple α-haloglutarimide is low-yielding and limited by substrate availability. We report a generalizable pathway to forming these alkylated N-heterocycles from abundant primary amines derived from amino acids via a unique Electron Donor-Acceptor (EDA) complex. Irradiation with blue light induces the formation of a diradical species, which recombines to form traditionally unstable and often inaccessible alkyl iodides in situ, which are displaced by the introduction of an exogenous nucleophile. Overall, this transformation introduces an umpolung approach to heteroarylation by converting primary amines into electrophilic coupling partners. When employing glutamate and glutamine derivatives, this strategy can enable efficient late-stage introduction of glutarimides.

Isocitrate lyase (ICL) from Mycobacterium tuberculosis is a key enzyme of the glyoxylate shunt required for survival during latent infection and is absent in humans. Maleate has long been characterized as a reversible competitive inhibitor that mimics the succinate product of catalysis. Here, we show that maleate instead functions as a slow, time-dependent covalent inactivator of ICL. Kinetic analysis supports a two-step mechanism involving reversible binding followed by irreversible modification of the catalytic cysteine residue, Cys191. Mass spectrometric analysis confirms covalent modification and, in the presence of glyoxylate, reveals an additional adduct incorporating both maleate and glyoxylate. Formation of this higher-mass species is consistent with enolate-like reactivity within the active site. Comparison with structurally related maleate analogues demonstrates that minimal substitution at the alkene abolishes covalent reactivity and alters the binding mode, highlighting the stringent geometric and electronic constraints imposed by the succinate-binding pocket. Together, these findings redefine the interaction of succinate analogues with ICL and provide mechanistic insight into active-site organization.

UHPLC-Orbitrap-HRMS-based metabolite identification and profiling of methylophiopogonone A, A bioactive constituent from Ophiopogon japonicus.

Hydrophobic Mn/ZSM-5 modification for highly efficient O3 decomposition under humidity conditions.

Bioelectrochemical methanation (BEM) can contribute to the energy transition by converting renewable electrical energy to synthetic methane, which can be transported and stored for prolonged periods of time in the natural gas grid. The BEM technology combines hydrogen production through water electrolysis and biomethanation in the same space. A major hurdle to commercializing the technology is its low productivity, which is largely caused by the low conductivity of the electrolytes. Increasing the conductivity of the catholyte by increasing the salt concentration is challenging because the biocatalyst, which facilitates the methanation, performs best within a certain salinity range. This work demonstrates that it is possible to utilize a highly productive biocatalyst outside of its optimum, at a higher salinity, and thus increase the performance of the bioelectrochemical system. The electrolyte design is further enhanced by switching the anion in the catholyte from chloride to sulfate. With the improved electrolyte design, a bioelectrochemical methanation system runs stably for multiple hundred hours and with a threefold increase in current density, showing a huge increase in performance. Furthermore, the formation of oxidative chlorine species is prevented, and thus, the fast degradation of materials is avoided. This brings the technology one step closer to commercialization.