ACS Omega最新文献

This study presents the development of an antiviral nonwoven nanofiber fabric composed of polyethylene terephthalate (PET) and alkali lignin, fabricated via solution electrospinning for potential use in face mask filtration media. Alkali lignin, a biobased antimicrobial agent, was incorporated into the PET matrix to enhance both antimicrobial and antiviral efficacy. Various PET concentrations and electrospinning parameters were optimized to achieve uniform, bead-free fibers with nanoscale diameters. Among the tested formulations, 20 wt % alkali lignin loading yielded nanofibers with an average diameter of 290 nm, demonstrating improved hydrophilicity and enhanced fiber morphology. SEM analysis confirmed the uniformity of the fiber structure, while FTIR spectroscopy suggested hydrogen bonding interactions between PET and lignin. Antimicrobial assays showed that the PET–lignin 20 wt % composite completely inhibited the growth of both Staphylococcus aureus and Escherichia coli within 1 h. Moreover, antiviral testing indicated more than a 2-log reduction in human coronavirus titers after 2 h of exposure. The fabricated PET–lignin nanofibers offer a sustainable alternative to conventional polypropylene-based mask materials, featuring enhanced biocompatibility and potential recyclability. These findings highlight the prospective utilization of lignin-integrated PET nanofibers in advanced healthcare and biomedical applications, including antiviral filtration, medical textiles, and tissue engineering scaffolds, while contributing to environmental sustainability through the reutilization of biowaste-derived compounds.

Titanium is a versatile material that can be used both as a semiconductor in heterogeneous photocatalysis and in the medical field, mainly to produce implants aimed at restoring, replacing, and correcting biological structures with poor osseointegration performance. This versatility is directly related to its unique properties, such as low toxicity, chemical stability, ability to absorb UV light, durability, stability at different pHs, and photosensitivity. Therefore, this study aims to compare titanium anodizing in Psidium guajava using an anodizing bench with the industrial process. For this purpose, samples anodized in Psidium guajava and anodized by the industrial process (H₃PO4 or H₃PO₄ + HF) were compared regarding morphology, roughness, color, electrochemical corrosion tests, and Raman spectroscopy. Additionally, heterogeneous photocatalysis tests were also performed to assess the photocatalytic activity of TiO₂ in the degradation of methylene blue dye. It was found that the samples anodized with the Psidium guajava electrolyte showed high photoactivity (99%) in the degradation of methylene blue, in addition to a performance similar to that of H₃PO₄ + HF and better than that of H₃PO₄. This can be attributed to the presence of phenolic compounds such as quercetin and indicates that Psidium guajava anodizing is an efficient and sustainable alternative to the industrial process.

Investigating the propagation behavior of hydraulic fractures in shale reservoirs under high-stress conditions in deep formations is critically important. This study utilized full-diameter shale cores and conducted hydraulic fracturing experiments through a self-developed triaxial hydraulic fracturing experimental system for high-stress rocks. The research focused on the propagation laws of hydraulic fractures in shale under high axial stress conditions and the variation patterns of the acoustic emission (AE) b-value during fracture propagation. The results indicate that the hydraulic fracturing pressure curves under different confining pressures exhibit two patterns during the shale failure stage: single breakdown and secondary breakdown. Under low confining pressure, the fracturing fluid is prone to leak-off in the hydraulic fracture channel formed during a single breakdown event. In contrast, under high confining pressure, the fracturing fluid is less likely to leak-off in the hydraulic fracture channel formed during the first breakdown of the secondary failure process. The energy accumulated by the fracturing fluid in the fracture channel leads to refracturing of the shale. Thus, under high confining pressure, shale specimens are prone to forming complex fracture networks. As the confining pressure increases, the morphology of hydraulic fractures transitions from simple to complex, and the fracture propagation direction becomes less constrained by the maximum principal stress. Under a high confining pressure of 59 MPa and a stress difference coefficient of 0, shale specimens are more likely to form complex fracture networks during hydraulic fracturing, while the peak AE b-value is correspondingly lower. This study provides a qualitative understanding and scientific explanation of the propagation behavior of hydraulic fractures in shale under high confining pressure conditions.

In the first part of this study, we have examined the shrinkage of hydrophilic gels during epitachophoresis, an isotachophoresis-like discontinuous electrophoretic technique, applied to concentrate DNA samples. In the present work, we evaluated selected solid porous media (sponges, nanofibers, foamed polymers, membranes, and structured inserts) as alternative anticonvective media. All materials were assessed based on zone shape, ease of creating the boundary between the leading and trailing electrolytes, and the DNA recovery. While nanofibers and most sponges resulted in poor separation or high analyte adsorption, mechanically supported agarose gels and filtration membranes provided sharp dye zones and high DNA recovery. Foamed polymers, especially plasma-treated ultrahigh molecular weight polyethylene, showed the best overall performance. Some rigid open structures (e.g., silica columns or nylon nets) demonstrated potential for large analytes but require further optimization. These results highlight key design considerations for robust, scalable epitachophoresis devices for preparative DNA concentration using solid-state stabilization media.

The escalating crisis of bacterial resistance necessitates the development of novel antimicrobial agents. Herein, we report the synthesis and comprehensive characterization of a new zinc(II) coordination compound, [Zn(phen)(maleate)(H₂O)]·H₂O (phen = 1,10-phenanthroline). Single-crystal X-ray diffraction revealed a distorted square pyramidal geometry around the Zn(II) center, forming a supramolecular framework (triclinic, $P\overline{1}$) stabilized by hydrogen bonding (H···O/O···H: 30.6%) and π–π stacking interactions (C···C: 9.0%), as quantified by Hirshfeld surface analysis. Periodic density functional theory (DFT) calculations confirmed a direct energy gap of 3.45 eV and thermodynamic stability under ambient conditions. Vibrational spectroscopy (infrared and Raman) combined with DFT calculations provided suitable mode assignments. The compound exhibited selective antibacterial activity against Gram-positive Streptococcus mutans (MIC = 1000 μg/mL) with no activity against Gram-negative Escherichia coli. Systematic control experiments confirmed that antibacterial activity originates from the intact coordination complex rather than individual components. In silico pharmacokinetics predictions indicated favorable gastrointestinal absorption, full compliance with drug-likeness rules (Lipinski, Ghose, Veber, Egan, Muegge), and no cytochrome P450 inhibition. Molecular docking studies revealed specific binding to a S. mutans enzyme (ΔG = −7.4 kJ/mol), suggesting enzyme inhibition as the primary mechanism. This work establishes a multidisciplinary framework for rational Zn-coordination compounds design while highlighting critical needs for toxicological validation and structural optimization to enhance potency and broaden antimicrobial spectrum.

Herein, two Cu(II) complexes of the type [Cu(N–N)(mftpy)](PF₆)₂ (N–N = 4-chloro-N-(pyridin-2-methylene) aniline (Clmp) or 4-methyl-N-(pyridin-2-methylene) aniline (memp)and mftpy = 4′-(4-methylphenyl)-2,2′:6′,2″-terpyridine) were successfully synthesized and characterized by microanalysis (% CHN), high-resolution mass spectrometry, Fourier-transform infrared spectroscopy, and ultraviolet–visible (solution and solid state) and electron paramagnetic resonance spectroscopies (solution and solid state). Next, the in vitro antibacterial activity of the [Cu(Clmp)(mftpy)](PF₆)₂ CL1 and [Cu(memp)(mftpy)](PF₆)₂ CL2 complexes was investigated in the planktonic and sessile form of Campylobacter jejuni and Campylobacter coli strains selected from a bank of strains characterized by resistance to first-line antibiotics. The quantification of planktonic cells showed a reduction that varied from 1.3 to 6.9 log CFU (colony forming units)/mL at a minimum inhibitory concentration of 25–400 μg/mL according to the tested strain. The biofilms suffered modification in their ultrastructure and showed evidence of the action of both complexes that surpassed the results with peracetic acid, with a reduction ≥2.6 log CFU/mL of sessile Campylobacter, with control of 1.2 orders of magnitude in the biomass formation by CL2, and the highest penetration (4.92 μg) of CL1 into the C. jejuni biofilm. The results identified show that both complexes are biologically active, activating processes that allow the control of the pathogen in both lifestyles.

Three-dimensional (3D) metal–organic frameworks (MOFs), are known by various names, such as organic zeolite analogues, 3D porous coordination polymers, hybrid organic–inorganic materials, coordination polymers, and metal–organic polymers, are advanced three-dimensional materials distinguished by their high surface area, tunable surface properties, and well-defined crystalline structures. Due to these exceptional characteristics, MOFs have been extensively explored for applications in diverse fields, including gas storage, chemical separation, ion exchange, and catalysis. 3D cyclodextrin-based metal–organic frameworks (CD-MOFs) have emerged as a biocompatible alternative to conventional MOFs, as they are synthesized using safer, nontoxic, or lower-toxicity components, thereby eliminating the need for potentially hazardous metals and organic linkers commonly employed in traditional MOF synthesis. In CD-MOFs, cyclodextrin molecules serve as organic linkers, while metal sources, such as KOH, NaOH, and KCl, provide the necessary metal ions for framework formation. CD-MOFs form body-centered cubic structures by binding to one of the alkali metal cations through coordination of the secondary face hydroxyl groups on the alternate d-glucopyranosyl residues. Beyond the intrinsic advantages of traditional MOFs, CD-MOFs offer additional benefits, particularly in drug delivery applications, where biocompatibility is a crucial factor. These CD-MOFs can be synthesized through various techniques, and multiple strategies can be employed for drug loading. This review comprehensively examines the synthesis of 3D CD-MOFs, their drug loading methodologies, comparative analysis of these methods in terms of advantages and limitations, and the potential of 3D CD-MOFs as drug delivery systems.

The development of solid-state electrolytes (SSEs), which are essential for enabling safe and effective sodium-ion batteries, is being accelerated by machine learning (ML). This study evaluated the potential of a NASICON-type Na₄Hf₂(SiO₄)₃compound as a promising SSE by using ML techniques in conjunction with density functional theory (DFT). A predictive machine learning model was developed based on ionic conductivity data from the literature reported experimentally. The model was trained on log-transformed conductivity and temperature, and features were selected using statistical correlation techniques. SHAP analysis was used to identify key characteristics influencing ionic transport. Because materials databases lack specific filters for NASICON-type compounds, hypothetical structures were developed for model validation. Na₄Hf₂(SiO₄)₃was chosen due to its high expected conductivity and structural stability. DFT validation included assessments of electronic band gap and dynamical, thermal, and mechanical stability in addition to ionic conductivity, which was computed using molecular dynamics simulations. This study demonstrates the usefulness of a hybrid ML-DFT strategy in accelerating the search for solid-state electrolytes.

Cleaner alternatives to internal combustion engines are essential for reducing pollution emissions while maintaining performance. In this study, a ternary blend of diesel, biodiesel, and propanol (80:10:10 by volume) was prepared and enriched with multiwalled carbon nanotubes (MWCNTs) at concentrations of 40, 60, and 80 ppm to evaluate its combustion, performance, and emission in a monocylinder diesel engine. Compared to diesel fuel, the ternary blends with MWCNTs demonstrated an increase of up to 6.73% in the net heat release rate and an average decrease of up to 14.74% in cylinder pressure. Engine performance improved with a rise in the brake thermal efficiency up to 11.79% on average, while the brake-specific fuel consumption decreased by up to an average of 6.04%. Emission analysis indicated substantial reductions in carbon dioxide (up to 18.72%) and nitrogen oxides (up to 42.39%), whereas unburned hydrocarbons increased by an average of 26.66%. These results indicate that the synergistic interaction among biodiesel oxygen content, propanol volatility, and the catalytic/thermal conductivity properties of MWCNTs enables improved combustion efficiency while mitigating carbon dioxide and nitrogen oxides. This study provides new insight into the role of carbon-based nanomaterials in enhancing oxygenated ternary diesel blends and highlights their potential to support cleaner and more efficient compression ignition engine operation.

The search for low-cost and sustainable adsorbents for dye removal has driven the valorization of agro-industrial residues. In this study, pecan nutshells (PNSs) were evaluated as a biosorbent for methylene blue (MB) removal. The material was prepared by drying, grinding, and alkaline treatment with NaOH, which led to an increase in the apparent surface area (0.974 m²·g^–1) and pore volume (0.0014 cm³·g^–1). Surface characterization revealed the involvement of hydroxyl, carboxyl, and aromatic functional groups in the interaction with the dye molecules. The adsorption of MB by PNSs exhibited high efficiency, even at low dosages, and optimal performance was observed at 1.5 g·L^–1. The process remained essentially pH-independent across the 4–10 range. Equilibrium data were analyzed using the Langmuir, Freundlich, Dubinin–Radushkevich, and Sips isotherm models. Among them, the Sips model provided the best fit to the experimental data, yielding a maximum adsorption capacity of 317.5 mg·g^–1 at 25 °C, which is consistent with a heterogeneous surface presenting finite saturation. The thermodynamic parameters (ΔH° = +12.32 kJ·mol^–1; ΔG° = −13.43 kJ·mol^–1 at 25 °C; ΔS° = +86.27 J·mol^–1·K^–1) indicate that the adsorption process is spontaneous and endothermic, with an enthalpy change characteristic of weak to moderate interactions. Kinetic data were best described by the pseudo-second-order model, with equilibrium reached within approximately 180 min. Intraparticle diffusion analysis revealed a multistep adsorption involving an initial boundary-layer diffusion followed by a slower pore diffusion. Overall, the adsorption mechanism is interpreted as multifactorial, governed by hydrogen bonding, π–π stacking, and van der Waals forces, consistent with a physisorption-dominated process strengthened by structural heterogeneity. These results demonstrate that PNS combines high capacity with operational simplicity, representing a scalable and sustainable alternative for the treatment of dye-contaminated wastewater.