ACS Omega最新文献

Glutathione reductase (GR) is a homodimeric flavoenzyme that regenerates reduced glutathione, essential for cellular redox balance, with an active site cleft at the upper dimer interface. However, the role of intramolecular interactions within each monomer in maintaining the dimer interface and influencing enzyme activity remains unclear. This study investigates how hydrophobic interactions within each monomer near the dimer interface, particularly involving L416 (α12 helix) and F443 (α14 helix), affect the stability and activity of GR from the psychrotrophic bacterium Pseudomonas mandelii JR-1 (PmGR). Mutations at L416 (L416A, L416E, L416Q) preserved the dimeric form during native polyacrylamide gel electrophoresis at 4 and 50 °C but reduced catalytic function, with activity progressively declining at 50 and 60 °C. In contrast, F443A remained dimeric only at 4 °C, while F443E and L416A/F443A disrupted hydrophobic interactions, causing dimer dissociation at 4 °C and severely impairing enzyme activity. F443L, however, retained dimerization under all tested conditions. Despite these disruptions, all mutants except F443A retained their secondary structure. These findings demonstrate that L416 in the longer α12 helix modulates enzyme kinetics without destabilizing the dimer interface, whereas hydrophobic interactions involving F443 in the shorter α14 helix are critical for dimer integrity and activity. This study highlights the essential role of hydrophobic interactions within each monomer, particularly those involving F443, alongside dimer interface interactions, in maintaining GR stability and activity, offering valuable insights for GR engineering in oxidative stress defense.

Recently, a novel class of emerging 2D materials identified as MXene have been revolutionizing the fabrication and development of flexible energy storage systems, i.e., batteries and supercapacitors. Herein, the focus is on the remarkable capacitive performance of V₂CT_x MXene-based flexible electrodes so far poorly explored. However, research was focused on Ti₃C₂T_x and its applications in the energy field, although more than 100 other members of this group have already been reported. Some of these MXenes are emerging as potential candidates for energy applications with promising results such as Ti₂C and Mo₂C in aqueous electrolytes, but many others remain to be explored. The paper detailed a comprehensive study of the electrophoretic deposition of V₂CT_x on carbon yarn wires and the evaluation of their electrochemical behavior (capacitive and diffusive) in three electrolytes at different pH values: acidic, basic, and neutral pH to investigate the correct potential window for this material in energy applications. The devices exhibited specific capacitances of 248, 177, and 89 F g^–1 for EPD10, EPD20, and EPD30, respectively. The synthesized and deposited MXene nanoparticles were analyzed by XRD, Raman, and SEM for phase identification, chemical structure identification, and morphological analysis, respectively. The synthesized material showed good electrochemical performance in terms of cyclic stability after 3000 cycles with >90% capacitance retention.

Hydrogenation saturation of phenanthrene (a typical component of coal tar) could not only improve the combustion performance of fuel oil, but also obtain the raw material for preparing high-energy-density fuel. Nickel-based catalysts have been considered promising catalysts for the hydrogenation saturation of phenanthrene due to their appealing capacity to activate phenanthrene molecules. However, the Ni derivation precursor greatly affects its hydrogenation activity. In this work, the NiAl₂O₄ catalyst was obtained by the sol–gel method. Under the experimental conditions of temperature 300 °C, pressure 5 MPa, and WHSV 0.52 h^–1, the phenanthrene conversion over NiAl₂O₄ catalysts can be up to 99.7 and 93.9% for perhydrophenanthrene yield, while those of the traditional Ni/Al₂O₃ catalysts are just up to 96.8 and 77.3%, respectively. Moreover, the TOF of phenanthrene hydrogenation of the NiAl₂O₄ catalyst (3.01 × 10^–3 s^–1) surpasses that of the traditional Ni/Al₂O₃ catalyst (2.46 × 10^–3 s^–1), which indicates that Ni derived from NiAl₂O₄ has stronger phenanthrene hydrogenation activity. According to relevant characterizations, the superior hydrogenation performance of the NiAl₂O₄ catalyst derives from the stronger H₂ adsorption and dissociation ability and the formation of an electron-deficient structure of active metal Ni, which contributes to the improved adsorption and activation of the polycyclic aromatic hydrocarbons.

Background: Carvedilol can be used in the treatment of rosacea. However, their oral administration often results in a series of adverse effects. Purpose: A novel thermosensitive hydrogel was developed to improve the administration of carvedilol in the treatment of rosacea and to evaluate its safety and efficacy. Methods: The thermosensitive hydrogel was formulated using varying ratios of poloxamer 407 (P407) and poloxamer 188 (P188), with carvedilol being encapsulated during the process. The gel temperature and time of the hydrogel were observed, its phase transition was assessed through the inverted tube test, its microstructure was examined using scanning electron microscopy (SEM), and its characteristic functional groups were identified with Fourier transform infrared spectrometry (FTIR). The hydrogel’s therapeutic efficacy on a rosacea-like phenotype in mice was evaluated through in vitro experiments. Results: It is observed that the microstructure of the hydrogel possesses a porous structure, with pores uniformly arranged in a square lattice measuring 8–12 μm in diameter. Thermosensitive hydrogel encapsulated carvedilol (Car-P407₂₄/P188₁) had favorable drug release rate and swelling properties. Live/dead cell assays indicated minimal toxicity of the hydrogel to HaCaT cells, and the carvedilol encapsulated with hydrogel possessed a better therapeutic effect on the rosacea-like phenotype in mice. Conclusion: Car-P407₂₄/P188₁ was not significantly cytotoxic and possessed good cellular biocompatibility. Furthermore, it exhibits a good therapeutic effect on rosacea-associated facial flushing and erythema. It possesses some anti-inflammatory properties and exhibits great potential for future use in rosacea treatment.

Inhalation of polycyclic aromatic hydrocarbons (PAHs) derived from emissions of solid waste combustion is of public health concern, as PAHs are associated with respiratory cancers and inflammatory diseases. Here, we chose seven individual PAHs associated with gene expression changes induced by exposure to plastic incineration emission mixtures in human nasal epithelial cells in vitro and further elucidated inflammatory cytokine release and expression of aryl hydrocarbon (AhR) pathway gene response by these PAHs and ranked their toxicities. Overall ranking analyses showed differential inflammatory and gene expression potentials among PAHs, with high-molecular-weight PAHs inducing responses greater than those of their low-molecular-weight counterparts. Observed findings causally link PAHs contained in combustion mixtures with biological responses and highlight the importance of understanding chemical profiles in combustion emissions to properly estimate the human respiratory hazard potentials.

Recent advancements in topological states have expanded from insulators to semimetals and metals, characterized by band crossings near the Fermi level. In this study, we use first-principles calculations and crystal symmetry analysis to uncover a complex nodal structure in cubic compound Na₃PdCl₆. This structure, formed by only two bands, features six intersecting butterfly-like nodal lines on the (110) surface, protected by mirror symmetry M₁₁₀. The associated surface states span the entire Brillouin zone, enhancing the experimental observability. Remarkably, this nodal line configuration remains robust under both Hubbard correction and spin–orbit coupling effects, highlighting Na₃PdCl₆ as a promising material for both research and applications. To further provide a practical reference, the stabilities of Na₃PdCl₆ have been verified from different perspectives and several important mechanical parameters have been derived. The well-defined band structure, simple topological configuration, and robust surface state render Na₃PdCl₆ a compelling candidate for both theoretical exploration and experimental validation, suggesting significant potential for further research and potential applications.

Recently, two-dimensional transition metal borides (2D MBenes) have demonstrated advanced physical, mechanical, and electrochemical performance; however, there are fewer studies in the literature. In particular, 2D molybdenum boride (2D MoB), created from molybdenum aluminum boride (MoAlB, MAB phase), is one of the important materials introduced due to its thermodynamically stable structure. Herein, we present the preparation of MoAlB and its chemical exfoliation by employing NaOH and LiF-HCl etching solutions to synthesize 2D MoB MBene nanostructures. It is found that the etching conditions significantly affect the selective extraction of the interlayer Al from the MAB phase in solution, forming 2D MoB MBene nanostructures. The resulting 2D MoB MBene illustrates sheet-like morphology, abundant redox active sites, and moderate textural features, which are critical for electrolyte accumulation and transfer. Powder X-ray Diffraction (PXRD) analysis confirmed the crystallinity and phase purity, while Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the sheet-like morphology and structural integrity. X-ray Photoelectron Spectroscopy (XPS) was employed to analyze the elemental composition and oxidation states, confirming the successful removal of Al and the formation of MoB MBene. Additionally, Brunauer–Emmett–Teller (BET) surface area analysis provided insights into the porous nature and surface area, which are crucial for electrolyte interactions. The all-solid-state flexible interdigitated supercapacitor (ISSC) device prepared using 10/MoAl_1–xB electrode exhibited a good areal capacitance of 20.3 mF/cm², outstanding cyclic capability with 92% capacitance retention after 1300 cycles, and remarkable flexibility. Last but not least, the Density Functional Theory (DFT) of the optimal MoB sample was constructed in terms of structural, conductivity, and thermodynamic stability perspectives, which is well-aligned with experimental results. Applying these 2D MoB MBene electrodes as all-solid-state flexible interdigitated electrodes opens a new avenue in supercapacitor technology.

Homology modeling can help bridge the gap between missing 3D structures and available primary sequences of protein. More environmentally friendlier insecticides against domestic nuisance can target the octopamine receptor proteins, only expressed in invertebrates. Herein, octopamine receptor homologues from Periplaneta americana and Culex quinquefasciatus, which do not have tertiary structures in the Protein Data Bank (PDB), were built using homology modeling and evaluated with various molecular modeling tools. AlphaFold models (AFM), which use artificial intelligence from DeepMind, showed structural validity when superimposed on Swiss-Model models (SMM) for both insect octopamine receptor species. The UCSF Chimera and Modeler models (CMM) did not match those by AlphaFold and Swiss-Model irrespective of the insect species receptor model compared. The greatest discrepancy between any two structures resulted between AFM and CMM with only 21.46% similarity and 14.92% similarity between backbone αCs of their superimposed 3D structures, respectively, for cockroach and mosquito, yet their primary sequences are highly identical. The highest sequence identity for superimposed 3D structures occurred between AFM and SMM of cockroach at 75%, and their corresponding mosquito sequence at 35.12% just surpassed the threshold of pairwise structural validity set above 30%. The local model quality obtained from ProSA web server ranks AFM above SMM and CMM in that order, even though all models had good z-scores. Ramachandran plot paints a different picture where the CMM have a higher percentage of residues in the accepted zone and AFM have a few residues in the wrong places. However, the data from VADAR statistics show that AFM models are more thermodynamically stable with lower fraction of buried amino acids or charges. Docking studies conducted on UCSF Chimera software showed similarity in active site residues for AFM and SMM involved in a number of electrostatic and hydrophobic interactions. These include residues GLU202, LEU102, ASP95, and ASP105 for cockroach models and residues VAL24 and LEU174 for mosquito models. The active site of all protein models contains some identical residues found in bound complexes including GLU, LEU, APS, and SER, which happen to be in different positions. ANOVA analysis revealed no significant difference in docking energies, an indication that even when active site residues are different, they still conserve the essential qualities needed for binding. Thus, despite the differences in structures, based on validation evaluation, such differences are unlikely to affect binding with octopamine. However, for studies where the quaternary structure of a protein is crucial, the AFM that preserves the full quaternary structure is recommendable.

This work reports the determination of mercury and the assessment of health risks in water, river sediments, and soil samples collected in the city of Jacobina, Brazil, located in a region impacted by gold mining. The mercury determinations were performed using the direct method analyzer (DMA) method, which was carefully validated according to the IUPAC recommendations. Total mercury contents ranged from 0.10 to 1.77 μg L^–1 in water samples, from 0.005 to 0.278 μg g^–1 in soil samples, and from 0.014 to 0.317 μg g^–1 in river sediment samples. The contamination factor (CF) and the ecological risk index were applied to the data obtained from soil and sediment analyses. Only one of the twenty-one soil samples had CF > 1 (1.11), denoting moderate contamination for this sampled site. All 20 other samples had CF < 1 (0.02 to 0.69), showing low mercury contamination in the soils collected throughout Jacobina. The results of the ecological risk index perfectly corroborated the results found by the CF, denoting that only one sample had a moderate potential ecological risk. Among the 13 sediment samples, two had CF > 1 and Er in the range of 40 to 80, denoting moderate contamination and moderate ecological risk in these two sampled locations. All 11 other samples had CF < 1 and Er less than 40, demonstrating that the sediments analyzed have low contamination and low potential for ecological risk due to mercury. All mercury levels found in water samples are below the maximum limit (2 μg L^–1) established by the CONAMA, the Brazilian Government, for class 3 freshwater. The assessment of daily mercury exposure was also performed using the routes of exposure through dermal contact (ADIder), inhalation (ADIinh), ingestion (ADIing) in the soil samples, and dermal contact and ingestion in the water samples employing the health risk indices established by the USEPA. The results obtained did not indicate noncarcinogenic risks for adults and children.