ACS Omega最新文献

Currently, reported estimates indicate that there are 1.03 million annual cases of leptospirosis, with 58,900 deaths worldwide. The Pan American Health Organization (PAHO) in 2022 indicates that the febrile symptoms of leptospirosis are similar to other diseases such as influenza and dengue, among other diseases. Therefore, an early and accurate diagnosis of leptospirosis is essential for adequate and rapid treatment. In this study, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy combined with multivariate analysis techniques was employed to classify between healthy controls and leptospirosis positive samples. Spectra from 113 dried blood plasma samples from patients (n = 43 leptospirosis, and n = 80 controls) were analyzed by linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), and support vector machine (SVM), combined with genetic algorithm (GA), successive projections algorithm (SPA), and principal component analysis (PCA) for feature selection/extraction. The GA-LDA model showed good sensitivity at 85.71% and specificity at 100% to discriminate both classes. Cross-validation was also performed, with the Venetian blinds method, showing the GA-LDA-CV model with better results in percentage sensitivity (76%), specificity (91%), precision (83%) and acurracy (86%), F-score (0.828), and AUC (0.835), when compared with the results of the preliminary GA-LDA model, and it is possible to rule out the possibility of overfitting of the preliminary GA-LDA model. Suggesting that combined ATR-FTIR spectroscopy with multivariate analysis has great potential to detect biochemical variations produced by the Leptospira pathogen in the blood of infected patients. These findings emerge as a new potential tool for improving leptospirosis diagnosis in the future using a rapid, low-cost, and minimally invasive methodology.

The long-term accumulation of magnesium (Mg(II)) ions in human patients resulting from the biodegradation of clinical Mg (alloy) implants is investigated using a physiologically based pharmakinetic (PBPK) mathematical model. In severe cases, an excess of Mg in blood (hypermagnesemia) causes a range of health concerns and potentially death. Studies investigating clinical Mg devices generally indicate that there is little risk in healthy patients; however, there is concern that excessive Mg accumulation may occur in patients who are elderly, have osteoporosis, and/or have renal disease. The PBPK model describes the time evolution of Mg concentrations in blood, tissue, and bone compartments in response to Mg sourced from diet and implant(s) devices, over the implant’s lifetime. It predicts that Mg absorption in the tissue and bone compartments is the key factor in modulating long-term serum levels due to their large volume and Mg load. Furthermore, the time scale of observable accumulation can take several months to years, suggesting that for vulnerable patients, the Mg levels should be monitored throughout the lifespan of an Mg implant. Most of the model parameters can be estimated from simple patient measurements; thus, the model is the first step toward a practical patient-specific framework for Mg and for other biodegradable implant devices to inform medical treatments in response to the potential long-term accumulation of biodegraded products.

This report serves two main purposes: (1) to correct the literature in the area of multicomponent synthesis involving aryl aldehydes and trapped enols 4-hydroxycoumarin 1 or 4-hydroxy-6-methyl-2-pyrone 2 and (2) to fully characterize the dimerization products bis-coumarins 3 and bis-pyrones 4. There have been many reports of cyclizations occurring with these species and various catalysts; however, many products have been mis-characterized and are, in fact, dimers. We successfully synthesized these dimers using a green, one-pot reaction in water that avoids hazardous organic solvents, uses a catalytic amount of acid, does not require chromatography for purification, and has strong green chemistry metrics. Our simplified procedure resulted in high yields of dimers ranging from 24 to 96% including the first report of a meta-substituted bis-pyrone 4i. Herein, we report a green method for their synthesis, along with their photophysical properties, full characterization, and potential as AChE inhibitors for anti-Alzheimer’s therapy.

In this work, molecular descriptors of halogen/cyano-substituted alkanes (HCSAs), RX (X = F, Cl, Br, I and CN), were extracted using a hierarchical molecular structure method. They are divided into three hierarchies: number of vertices, vertex skeleton, and functional group, including the vertex number (m), sum of vertex number effect (S_VNE), odd–even index (OEI), intramolecular polarization effect index (IMPI), polarization effect index (PEI) of group, and group influencing factor (G_n). The properties (such as boiling point and refractive index) of each series of HCSAs can be quantitatively correlated well using these six molecular descriptors. The results show that the average absolute percentage error (APPE) between the experimental and calculated values for each series of HCSAs is less than 1%. However, some properties (such as critical temperature and critical volume) of HCSAs lack sufficient experimental data to develop class-specific estimation equations. Instead, they can be incorporated into a general estimation equation by adding the functional group characteristic parameter (ΔP_X) and the electronegativity (χ_X) of the group for all five series of HCSAs. These general quantitative correlation equations exhibit good estimation accuracy with APPE values all below 4%. Using the obtained estimation equations, the properties of HCSAs without experimental values were predicted, which include more than 1000 values of boiling point, density, refractive index, critical temperature, critical pressure, standard enthalpy of formation, and critical volume. This study provides a novel approach for establishing general equations to estimate the properties of monosubstituted alkanes with different functional groups.

Infections associated with titanium-based medical and dental implants present a major clinical challenge, as they can compromise osseointegration and long-term implant stability. Silver-based nanoparticles (NPs) are widely recognized for their strong antimicrobial properties, and when combined with titanium, they hold significant promise for developing infection-resistant and biocompatible implant surfaces. In this study, Ag/AgO/Ag₂O NPs were deposited onto highly porous TiO₂ layers formed on the Ti6Al4V alloy by microarc oxidation (MAO), with the aim of simultaneously enhancing antibacterial performance and supporting osteoblast activity. The NPs exhibited a predominant size of 8.7 ± 0.1 nm, with smaller particles oxidized to AgO and Ag₂O, and larger particles (∼10 nm) composed of metallic Ag. SEM evaluation revealed that the NPs were homogeneously dispersed across the oxide surfaces without altering the rough and porous morphology of TiO₂. The MAO-treated surfaces initially showed hydrophobic behavior (contact angle of 94.1 ± 0.3°), which shifted to hydrophilic after Ag/AgO/Ag₂O NP deposition due to increased hydroxyl group formation. Antibacterial assays against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) revealed a significant enhancement in antibacterial activity, particularly for surfaces with the highest Ag/AgO/Ag₂O NP density. Meanwhile, osteoblast cell viability assays demonstrated no reduction in metabolic activity after 72 h, and SEM images confirmed cell adhesion and proliferation. Overall, these findings highlight the potential of Ag/AgO/Ag₂O NP-modified TiO₂ surfaces as multifunctional coatings that combine infection resistance with osteoblast compatibility, offering promising applications in dental and orthopedic implants.

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.