ACS Omega最新文献

Pentosan polysulfate (PPS) is an approved drug for the treatment of interstitial cystitis in humans and osteoarthritis in animals. This semisynthetic highly sulfated polysaccharide shares structural similarities with heparin and also interacts with platelet factor 4 (PF4), the key protein implicated in thrombocytopenia, a serious side effect of heparin administration. Thrombocytopenia arises from an immune response to structural features of multimeric complexes of heparin and PF4, although the prediction of disease progression in patients is complicated by the variable polyclonal and polyspecific response. The potential risk of provoking a similar response to PPS or materials derivatized with PPS, which could include subcutaneous or intravenous applications for other therapeutic goals, therefore needs to be assessed. In the absence of a clear proxy measurement for the risk of PPS to induce HIT, the ability of PPS and its fractions to interact with PF4 was examined from a broad structural perspective, employing orthogonal techniques, which were compared with unfractionated heparins (UFHs) and low-molecular-weight heparins (LMWHs). Zeta potential analysis, isothermal titration microcalorimetry, and circular dichroism showed that PPS interacts with PF4 in a manner dependent on its molecular weight, exhibiting behavior intermediate between that of LMHW and UFH. The interaction of PPS size-separated fractions with PF4 also exhibited a dependence on M_w; higher M_w corresponding to stronger interactions, and the same trend was confirmed by atomic force microscopy. Interestingly, despite PPS forming complexes with PF4, and the complexes formed with PPS fractions being smaller than those formed with UFH and LMWH, enzyme immunoassay studies nevertheless demonstrated the formation of antigenic complexes. Since PPS provokes comparable interactions with PPS, the results suggest that close monitoring of potential thrombocytopenia effects will be necessary when considering PPS dosing, especially for intravenous applications.

Fly ash is an abundant industrial byproduct with potential as a particulate reinforcement in aluminum matrices, yet conventional stir casting often yields poor dispersion and weak interfaces. AA6061/fly ash composites containing 4–12 wt.% reinforcement were fabricated by compocasting (semisolid) and followed by material characterizations: XRD, SEM, fractography, hardness testing, and tensile testing. Reproducibility was assessed by analysis of variance (ANOVA), and performance was benchmarked against stir-cast counterparts. XRD detected no interfacial reaction products. SEM revealed a uniform dispersion of 20–50 μm particles, pore-free interfaces, and grain refinement, attributed to Zener pinning and heterogeneous nucleation. The microhardness doubled from 55 HV (unreinforced AA6061) to 110 HV (fly ash 12 wt.%), while the ultimate tensile strength increased from 140 to 249 MPa (+78%). Ductility decreased from 14% to 5%, consistent with the trade-offs associated with ceramic-particle toughening. Fractography revealed mixed-mode fracture surfaces with both intact and fractured particles, indicating robust interfacial bonding. ANOVA supported measurement reproducibility (p < 0.001). Relative to stir casting, compocasting yielded more uniform dispersion, lower porosity, and cleaner interfaces. Compocasting enables AA6061/fly ash composites with refined microstructures and substantially enhanced strength and hardness at the expense of reduced ductility. The process offers a practical route to valorize fly ash as reinforcement for weight-critical applications (automotive/aerospace) without deleterious interfacial reactions.

Increasing the recovery factor in oil fields is a critical task for improving reservoir performance and energy sustainability. This study investigates the novel application of graphene oxide (GO) nanoparticles as an enhanced oil recovery (EOR) agent in heavy oilfields, with an integrated multiscale approach combining laboratory experiments and numerical reservoir simulation. The nanofluids were optimized by evaluating the influence of salinity (300–900 ppm), pH (4–8), and GO concentrations (0.03–0.09 wt %) on interfacial tension (IFT) and wettability. Under optimal conditions (900 ppm brine, pH 8, and 0.09 wt % GO), the IFT decreased from 32.5 to 15.8 mN/m, and the contact angle shifted from 140° (oil-wet) to 90° (intermediate). Coreflooding tests confirmed the EOR potential of GO nanofluids, achieving 63.60% oil recovery compared to 56.72% with conventional waterflooding, an incremental gain of 7%. Relative permeability curves and advanced wettability indices (Lak and modified Lak) validated wettability alteration effects. To evaluate the scalability of this technology, the experimental data were incorporated into a numerical simulation using CMG-STARS. First, a history-matched core-scale model was developed to reproduce laboratory results. Then, a conceptual reservoir model was constructed using representative petrophysical properties from Colombian fields. The reservoir-scale simulation showed that nano-GO injection could yield an additional 402,431 barrels of oil over a 20-year period compared to conventional waterflooding, while maintaining a more favorable water cut. These findings highlight the potential of GO nanofluids as a viable and scalable EOR strategy for heavy-oil reservoirs. Future studies will focus on field-scale validation, economic feasibility, and environmental impact.

Pancreatic cancer has one of the highest mortality rates, and early detection remains a challenge, significantly limiting therapeutic strategies. In this study, we present the clinical validation of a novel multilayered capacitance-based biosensor for early pancreatic cancer detection. Poly(diallyldimethylammonium chloride) and (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate) (PDDA/PEDOT:SS) were physically adsorbed onto gold interdigitated electrodes via self-assembly, followed by surface functionalization with CA19-9 antibodies. Upon selective binding of the CA19-9 biomarker, the adsorption kinetics indicated that the system reached equilibrium within 7 min. Polarization modulation infrared reflection absorption spectroscopy, atomic force microscopy analysis, and electrical measurements confirmed the successful functionalization of the biosensor surface. The interaction between CA19-9 and the functionalized surface was evaluated using electrical impedance spectroscopy. The calibration curve was best fitted to the Langmuir–Freundlich model, and all data sets were processed by visual analysis (IDMAP). Key characteristics of the devices ─ sensitivity and selectivity ─ demonstrate a limit of detection of 0.01 U/mL, limit of quantification of 0.03 U/mL, and specificity toward CA19-9. Analyses were conducted on 24 blood samples collected from patients at different stages of the disease. The good performance at low and moderate CA19-9 concentrations was supported by IDMAP and Bland–Altman statistical analysis. The results confirmed the biosensor’s potential as an innovative, sensitive, and selective tool for early detection of pancreatic cancer, with the possibility of future technology transfer to the Brazilian Health System.

Local anodic oxidation has become a convenient technique for fabricating graphene oxide nanostructures in fundamental research (e.g., nanoelectronics). The process is typically controlled by tip–sample voltage, scanning speed, relative humidity, and tip characteristics (e.g., tip radius). The role of other parameters, such as the number of layers, load force, and graphene-substrate adhesion, is discussed in this paper. It is shown by atomic force microscopy, Kelvin probe force microscopy, and Raman spectroscopy that the oxidation of graphene is achievable only under specific conditions: low pulling force and sufficiently strong adhesion of graphene to its substrate. Such conditions ensure the stability of graphene on the surface and the proper formation of the water meniscus, which serves as a source of oxidizing ions, resulting in a reproducible oxidation process. Failure to comply with these conditions may lead to the formation of structures other than oxides (e.g., removal of graphene or the formation of air/water cavities under graphene), which is also demonstrated.

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.