ACS Omega最新文献

The development of biocompatible biopolymer foams loaded with antibiotics is crucial to advancing drug delivery systems in biomedical engineering. These materials offer controlled drug release and specialized functionalities for improved therapeutic outcomes. This study presents the development and characterization of antimicrobial polymeric biofoam materials loaded with the drug amoxicillin (AMX). The sustainable synthesis of these biopolymer foams involves a cost-effective, eco-friendly method that incorporates natural starch within poly(vinyl alcohol) (PVA) through an aldehyde cross-linking/stabilizing process. The highly porous structure of the biofoams enabled effective impregnation of the AMX drug using an innovative process involving ultrasonication and vacuum pressure to maximize efficiency and minimize biomaterial loss. The findings demonstrate the potential of these PVA/starch-based biofoams as versatile drug delivery systems with desirable physicochemical and biological characteristics. Detailed investigations were conducted to evaluate morphological features, chemical properties, swelling behavior, in vitro biodegradability, drug release profiles, cell culture, and antimicrobial activity tests of the prepared biofoam samples. Investigating the effect of controlled loading of AMX under laboratory conditions on its release profile and studying its biodegradation in various environments over time represent a critical aspect of this research. The optimal release profile under physiological conditions and the potent inhibition of bacterial growth against Escherichia coli and Staphylococcus aureus microorganisms by AMX-loaded biofoam materials highlight their potential for biomedical applications. These materials show promise for the in vivo administration and local treatment of bacterial infections.

Density functional theory (DFT) calculations have been used to develop a new approach to interpreting geminal (two-bond) ²J_CCH NMR spin-coupling constants in saccharides containing aldofuranosyl (five-membered) rings. In the biologically important β-d-ribofuranosyl and 2-deoxy-β-d-ribofuranosyl (2-deoxy-β-d-erythro-pentofuranosyl) rings that were used as models, many of the ²J_CCH values associated with coupling pathways involving an endocyclic C–C bond depend linearly on P/π, a measure of ring conformation. In most cases, the endocyclic C–C bond is present in the coupling pathway. In other cases, the ²J_CCH value depends linearly on either an adjacent C–C bond torsion angle or shows no systematic relationship with any endocyclic C–C bond torsion angle. In the latter case, secondary (remote) structural effects, defined as those that primarily affect C–C or C–H bond lengths in the C–C–H coupling pathway, cause the ²J_CCH value to behave with less predictability. These effects apparently cancel and lead to linearity involving an adjacent C–C bond in some cases. These findings provide a new conceptual framework to understand and exploit the dependencies of geminal ¹³C–¹H NMR spin-couplings on furanose ring conformation. They also reveal the effect of exocyclic C–O bond torsion angles on the magnitudes and signs of ²J_CCH values in saccharides, a complication that remains to be addressed before ²J_CCH values can be used quantitatively in single- and multi-state MA’AT modeling of redundant NMR J-values in furanosyl rings.

Solid fluidization is a green mining developed method for seabed nondiagenetic gas hydrate reservoirs, which can safely and controllably transport hydrate to land through seabed mining, closed fluidization, and gas–liquid–solid multiphase lift. However, there are many technical problems, such as hydrate and sediment fluidization and improvement of pipeline transportation capacity in the process of multiphase lift. Based on forced spiral flow in a vertical pipe, the numerical simulation of hydrate and sediment slurry in a vertical pipe with a twisted tape is carried out to explore the solid-carrying capacity of spiral flow and expand the safe boundary of multiphase flow. The effects of hydrate volume fraction, Reynolds number, hydrate particle size, and sediment particle size on turbulent kinetic energy, turbulent dissipation, solid volume fraction, and pressure of hydrate–sediment slurry have been studied. The results show that turbulent kinetic energy and turbulent dissipation decrease with the increase of hydrate volume fraction. The turbulent kinetic energy and turbulent dissipation increase with the increase of the Reynolds number. The concentration gradient of hydrate and sediment at the outlet section is larger than that of the horizontal spiral pipe. The hydrate particle volume fraction at the hydrate axis increases with the increase of hydrate volume fraction, Reynolds number, and hydrate particle size. Sediment particles are mainly distributed near the pipe wall, and hydrate particles are mainly distributed on the inner side of the sediment and form a high-concentration ring. The pressure change in the vertical pipe is similar to that in the horizontal pipe. When Re = 30,000, the critical volume fraction of hydrate blockage in the vertical pipe is 47%, while the critical volume fraction is 22% in the vertical smooth pipe. The transport capacity of hydrate particles is increased by 1.14 times. Under the same conditions, the pressure drop of the whole pipe exceeds that of the ordinary smooth pipe by about 15%.

Postconsumer polyolefins (r-POs) are leading plastic waste contributors today. This study reports, for the first time, the compatibilization of r-POs at a 50 kilogram (kg) scale with a styrene block copolymer compatibilizer in the presence of paraffin waxes as rheology modifiers (RMs). The addition of the rheological modifier (RM) and compatibilizer enhances the melt flow indices (MFIs) and mechanical properties, respectively. One aspect of this study is to compare the effectiveness of low-cost paraffin wax to that of specialized and expensive RMs in r-POs. The mechanical and rheological properties such as the melt flow index (MFI) of r-POs were compared in the presence of two types of RMs. Next, the study explores the challenges encountered when scaling the compatibilization of r-POs in the presence of paraffin wax from a 10-g to a 50-kg scale. The mechanical properties were determined and compared for samples at different scales. The study further investigated the effect of the method used for blending paraffin wax with r-PO and its impact on the value of their MFI and mechanical properties. This at-scale validation could pave the way for the commercialization of r-POs.

Examining how hypoglycemic medications affect brain function is one of the best approaches to addressing cognitive impairment. In this study, trelagliptin, a dipeptidyl peptidase-4 (DPP4) inhibitor, was utilized to assess memory loss in diabetic rats through fear conditioning tests. Trelagliptin restored fear memory in diabetic rats that had been disrupted over a relatively long period (24 h) or extended period (5 days). Moreover, trelagliptin treatment reduced the higher incidence of neuronal cell death in the cerebral cortex, as observed via Nissl or hematoxylin and eosin staining. Subsequent analyses revealed that diabetic rats exhibited elevated levels of inflammatory cytokines (p-IKKα and p-NFκB) and a trend toward oxidative damage, indicated by malondialdehyde (MDA), superoxide dismutase 2 (SOD2), and glutathione peroxidase 4 (GPX4) detection. However, administration of trelagliptin reversed these markers to baseline levels. Additionally, trelagliptin activated p-AMPK, p-AKT, and p-GSK-3β. Notably, trelagliptin upregulated the expression of postsynaptic density protein 95 (PSD95) and synaptotagmin 1 (SYT1) while downregulating amyloid precursor protein (APP) and beta-site amyloid precursor protein cleaving enzyme 1 (BACE1). These findings suggest that trelagliptin alleviates cognitive impairment in diabetic rats, likely through AMPK-AKT-GSK-3β-mediated mitigation of oxidative stress, enhancement of synaptic plasticity, and reduction of Aβ accumulation.

Aging, trauma, infection, illness, and accidents can lead to the disruption of various human tissues, including skin, bone, and cartilage. Tissue engineering aims to promote the growth of cells and tissues within the human body, with scaffolds serving as vehicles to deliver a combination of mechanical and molecular signals to create new tissues for body reconstruction. Composite materials have gained significant attention as an attractive alternative for scaffolding due to their ability to enhance multiple material properties. For instance, cellulose nanofibers are known for their high specific surface area, flexibility, and elasticity. However, their limited bioactivity and slow degradation rates restrict their suitability for tissue engineering applications. In contrast, niobium-based materials, which are biocompatible and nontoxic, have been underexplored in this field. In this study, silver niobate is investigated for the first time as a component of a composite material designed to provide biological activity to an aerogel, thereby creating a multifunctional scaffold for tissue regeneration. Silver niobate nanoparticles were successfully synthesized and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). The composite aerogels demonstrated improved thermal stability, hydrophilicity, bioactivity, and antimicrobial activity against Staphylococcus aureus. Additionally, the developed aerogels showed no cytotoxic effects on primary dermal fibroblast (HDFn) cells. These findings suggest that the silver niobate-based aerogel composite holds significant potential for applications in tissue regeneration, offering a promising avenue for the development of advanced biomaterials in regenerative medicine.

The current study aimed to create a modified injectable bone substitute (IBS) with improved osteogenic characteristics. To enhance the cement injectability and release properties of curcumin in vitro, we incorporated curcumin into β-tricalcium phosphate (β-TCP) to create the composite supplemented with sintered porous β-TCP microspheres, which maintained good injectability with an initial setting time of 5.0 ± 1.3 min and a mechanical strength of 20.67 ± 1.3 MPa for bone cements. The differentiation potential of preosteoblast (MC3T3-E1) to osteoblasts was significantly boosted by incorporating curcumin, which triggered Col I, upregulated OPN expression, and boosted alkaline phosphatase activity. Bone regeneration was hastened after the in vivo implantation of curcumin-modified brushite (BR4P2C) cement into the implanted femoral defects, and the rate of cement disintegration was accelerated. As a result, the translational application of modified BR4P2C in preliminary research has the potential to serve as an IBS with curcumin, which has an exceptional ability to repair bone lesions.

Lignin nanomicelle (LNM) synthesis via deep eutectic solvent (DES) has been optimized from a conventional duration of 2–3 days to a streamlined 12 h procedure utilizing autoclave reactor heating. This approach facilitates the efficient extraction of lignin from straw and its subsequent formation into LNMs via a simultaneous self-assembly mechanism. Integration of these amphiphilic LNMs into a cellulose nanocrystal (CNC) framework, combined with PEDOT: PSS in a poly(vinyl alcohol) (PVA) matrix, yields a self-powered strain sensor characterized by enhanced tensile properties and heightened strain sensitivity. Incorporating carboxyl functional groups from LNMs on the PVA matrix significantly augments the sensor’s mechanical strength and elasticity. This is evidenced by achieving Young’s modulus of 65.9 MPa and an elongation capacity of 320%, ensuring its efficacy in human motion detection. The synergistic inclusion of CNCs and LNMs amplifies the sensor’s gauge factor, thereby augmenting its strain responsiveness. The elevated aspect ratio of CNCs establishes an efficacious electrical network that, in concert with the interaction between CNCs and PEDOT: PSS, diminishes the electrical percolation threshold, culminating in an improved gauge factor of 19, indicative of enhanced strain detection capabilities. Furthermore, the sensor can generate a thermoelectric voltage in response to thermal gradients, with the dynamic structures of LNM improving the conductivity and PEDOT: PSS dispersion within the PVA matrix, thereby optimizing the Seebeck coefficient. After enduring 5000 cycles of 100% strain deformation tests, the sensor demonstrates consistent performance, underscoring its reliability and durability. The fabricated PVA/Gly–LNM/CNCs/PEDOT: PSS composite material has been successfully applied to detect nuanced human gestures, including finger and wrist movements, affirming its potential utility in wearable technology applications.

Titanium dioxide (TiO₂) is the most widely used white coating additive, and the solid content of the aqueous dispersion system is an important factor affecting productivity during its processing sanding. Achieving high solid content dispersion with low viscosity and high stability is crucial for enhancing its productivity; however, this objective currently presents a significant challenge. In this work, we propose a simple strategy for the use of low-molecular-weight poly(acrylic acid) sodium salt (PAAS) as an efficient dispersant for TiO₂ dispersion. We quantitatively characterized the stability of TiO₂ dispersions when different molecular weights of PAAS were used as a dispersant using a Turbiscan analyzer based on the multiple light scattering technique, and also investigated the viscosity and ζ potential. It was found that through the steric hindrance and electrostatic repulsion provided by PAAS, the PAAS with a molecular weight of 6000 g·mol^–1 could afford TiO₂ dispersion with solid content as high as 50%, exceptional dispersive stability, and low viscosity as 43 mPa·s at the shear rate of 100 s^–1. Owing to the high TiO₂ content, high stability, and low viscosity, this PAAS-dispersed aqueous dispersion shows great potential in TiO₂ production industry.

Black phosphorus (BP) has a low electrical conductivity and a high thermal conductivity, despite its narrow band gap and high Seebeck coefficient. Here, it is experimentally demonstrated that the Sn atoms are substitutionally doped into BP polycrystals and that multiscale microstructural defects, such as point defects, dislocations, and amorphous phases, as phonon scattering sites, are independently incorporated into them. The Sn doping into the BP polycrystal increases the carrier concentration up to 3.7 × 10¹⁸ cm^–3 at 300 K without a significant degradation of the Seebeck coefficient and effectively decreases the thermal conductivity due to the phonon-impurity scattering. The multiscale defects (point defects, dislocations, grain boundaries, amorphization) synergistically suppress the lattice thermal conductivity (from 13 to 6.3 W/m K) with a decoupling of the electronic transport. As a result, the thermoelectric figure-of-merit, ZT, is significantly enhanced more than 1 order of magnitude, by controlling the carrier concentration and the multiscale microstructural defects, independently.