Sunflower oil-based hyperbranched alkyd/spherical ZnO nanocomposite modeling for mechanical and anticorrosive applications

Approaches for designing advanced nanomaterials with hyperbranched architectures and lack of volatile organic content (VOC) have attracted considerable attention. In this study, eco-friendly hyperbranched alkyd resins for mechanical and anticorrosive coatings with high solid content were successfully synthesized based on sunflower oil (SFO) via a polyesterification approach. These resins are characterized by energy-efficient polymer synthesis, lack of gelation properties, high functionality, and low viscosity. A chemical precipitation process was used to fabricate zinc oxide (ZnO) spherical nanostructures with controlled diameters and morphologies. A series of conformal, novel, low-cost SFO-based hyperbranched alkyd/spherical ZnO nanocomposites were fabricated through an ex situ method. Various nanofiller concentrations were distributed to establish synergetic effects on the micro-nano binary scale performance of the materials. The features of the nanocomposites, including the molecular weight, acid and hydroxyl values of the prepared alkyd resins, were concomitantly assessed through various standard tests. The nanocomposites were also subjected to various tests to determine their surface adhesion and mechanical properties, such as impact, T-bending, crosscut, and abrasion resistance tests. Furthermore, the physico-mechanical properties, anticorrosive behavior, thermal stabilities and cellular cytotoxicities of the fabricated materials were assessed. The anticorrosive features of the nanocomposites were investigated through salt spray tests in 5 wt% NaCl. The results indicate that well-dispersed ZnO nanospheres (0.5%) in the interior of the hyperbranched alkyd matrix improve the durability and anticorrosive attributes of the composites; thus, they exhibit potential applications in eco-friendly surface coatings

Nitrogen-doped carbon hollow trunk-like structure as a portable electrochemical sensor for noradrenaline detection in neuronal cells

To date, the production and development of portable analytical devices for environmental and healthcare applications are rapidly growing. Herein, a portable electrochemical sensor for monitoring of noradrenaline (NA) secreted from living cells using mesoporous carbon-based materials was fabricated. The modification of the interdigitated electrode array (IDA) by nitrogen-doped mesoporous carbon spheres (N-doped MCS) and nitrogen-doped carbon hollow trunk-like structure (N-doped CHT) was used to fabricate the NA sensor. The N-doped CHT surface shows multiple holes distributed with micrometer-sized open holes (1–2 μm) and nanometer-sized thin walls (∼98 nm). The N-doped CHT surface heterogeneity of wrinkled and twisted hollow trunk structures improve the diffusion pathway and the NA molecules loading. The N-doped CHT/IDA showed a highly selective assay for monitoring of NA with high sensitivity (1770 μA/μM × cm2), a low detection limit (0.005 μM), and a wide linear range (0.01–0.3 μM). The N-doped CHT/IDA monitored the NA secreted from PC12 cells under various concentrations of simulation agents (KCl). The designed N-doped CHT/IDA provides a portable NA-sensor assay with facile signaling, good stability, high biocompatibility, in-vitro assay compatibility, and good reproducibility. Therefore, the designed sensor can be used as a portable sensor for NA detection in live cells and can be matched with portable smartphones after further developments

Mesoscopic Fabric Sheet Racks and Blocks as Catalysts with Efficiently Exposed Surfaces for Methanol and Ethanol Electrooxidation

Electrode designs based on sheet racks and blocks with multidiffuse groove spaces and enriched active sites and scales would promote the commercial applications of electroactive materials. A facile one‐pot hydrothermal approach is reported to synthesize mesoscopic porous Co3O4 or hybrid graphene (GO)/Co3O4 sheet‐on‐sheet racks and blocks. Three basic types of sheet scalability racks can be built in vertical and nonstacked edge orientations, such as neat micro/nanogroove rooms, butterfly wing scales, and wall groves, leading to highly exposed surface converges and sites. In particular, the stacked GO/Co3O4 sheet‐on‐sheet blocks (GO/Co3O4 blocks) can be oriented in vertical tower buildings. The atomic structures of the developed Co3O4 catalysts are dominant along the highly dense {112/111} interfaces and single crystal {111} and {112} facets. The electrochemical performance of the mesoscopic porous Co3O4 catalyst toward methanol and ethanol electrooxidation is evaluated in alkaline conditions. The mesoscopic hybrid GO/Co3O4 racks reveal superior catalytic activity in terms of oxidation currents and onset potentials, indicating the effect of the synergetic role of active Co3+ sites along the densely exposed {112} facets, graphene counterparts, and hierarchically nonstacked sheet racks on the electroactive functionality. Results indicate that the mesoscopic GO/Co3O4 sheet catalyst is suitable for highly efficient electrochemical reactions

Three-Dimensional Circular Surface Curvature of a Spherule-Based Electrode for Selective Signaling and Dynamic Mobility of Norepinephrine in Living Cells

A highly sensitive protocol for signaling norepinephrine (NEP) in human fluids and neuronal cell line models should be established for clinical investigation of some neuronal diseases. A metal-free electrode catalyst was designed based on a sulfur-doped carbon spheroidal surface (S-CSN) and employed as a transducing element for selective signaling of NEP in biological samples. The designed electrode of S-CSN features a spherical construct and curvature surface to form a spheroidal nanolayer with an average layer size of <2 nm. S-CSN shows surface topography of a circular surface curvature with a rugged surface texture, ridge ends, and free open spaces between interlayers. The rich-space diversity surfaces offer highly active surface with facile molecular/electron diffusion, multi-diffusive centers, and high target loading along with in-/out-of-plane circular spheres of the S-CSN surface. The active doping of S atoms onto the carbon-based electrode creates an active transducing element with many active sites, strong binding to targeted molecules, facile diffusion of charges/molecules, long-term durability, and dense reactive exposure sites for signaling NEP at ultratrace levels. S-CSN could be a sensitive and selective nanosensor for signaling NEP and establishing a sensing protocol with high stability and reproducibility. The sensory protocol based on S-CSN exhibits high sensitivity and selectivity with a low detection limit of 0.001 μM and a wide linear range of 0.01–0.8 μM. The in vitro sensory protocol for NEP secreted from living cells (neuronal cell line model) under stimulated agents possesses high sensitivity, low cytotoxicity, and high biocompatibility. These results confirm the successful establishment of NEP sensor in human blood samples and neuronal cells for clinical investigation

Ultrasensitive in-vitro monitoring of monoamine neurotransmitters from dopaminergic cells

The design of biosensing assay of monoamine neurotransmitters (MANTs) such as epinephrine (Ep), norepinephrine (NE), and dopamine (DA), as well as the monitoring of these MANTs released from dopaminergic cells, are of particular interest. Electrochemical sensors based on the novel construction of nickel oxides (NiO) were fabricated and employed for electrochemical screening of MANTs. A novel NiO-lacy flower-like (NLF) geometrical structure with semi-spherical head surfaces connected with a trunk as an arm was achieved. The designed semi-spherical head associated with abundant and the well-dispersed tubular branches with needle-like open ends might lead to the creation of vascular vessels for facile diffusion and suitable accommodation of the released MANTs throughout active and wide-surface-area coverage, multi-diffusive pores, and caves with connective open macro-/meso-windows along the entire top-view nanoneedles of lacy flower head and trunk. These electrode surfaces possess high-index catalytic site facets associated with the formation of ridges/defects on {110}-top-cover surface dominants for strong binding, fast response, and signaling of MANTs. The NLF- modified electrode enabled high sensitivity for MANTs and a low limit of detection of 6 nM. Ultrasensitive in-vitro monitoring of DA released from dopaminergic cells (such as PC12) was realized. The NLF electrode was used to detect MANTs from its sources (PC12), and it could be used for clinical diagnosis

Vibrational analysis of an irregular single-walled carbon nanotube incorporating initial stress effects

In this work, an attempt is done to apply the eigenvalue approach as well as Donnell thin-shell theory to find out the vibrational analyses of an irregular single-walled carbon (ISWCNT) incorporating initial stress effects. The effects of surface irregularity and initial stresses on natural frequency of vibration of nano materials, especially for single-walled carbon nanotubes (SWCNTs), have not been investigated before, and most of the previous research have been carried for a regular and initial stress-free CNTs. Therefore, it must be emphasized that the vibrations of prestressed irregular SWCNT are novel and applicable for the design of nano oscillators and nanodevices, in which SWCNTs act as the most prevalent nanocomposite structural element. The surface irregularity is assumed in the parabolic form at the surface of SWCNT. A novel equation of motion and frequency equation is derived. The obtained numerical results provide a better representation of the vibration behavior of prestressed ISWCNTs. It has been observed that the presence of either surface irregularity or initial stress has notable effects on the natural frequency of vibration, particularly in the short-length SWCNTs. Numerical results show that the natural frequency of SWCNT decreases with increase in surface irregularity and initial stress parameters. To the authors’ best knowledge, the effect of surface irregularity and initial stresses on the vibration behavior of SWCNTs has not yet been studied, and the present work is an attempt to find out this effectiveness. In addition, the results of the present analysis may serve as useful references for the application and the design of nano oscillators and nanodevices, in which SWCNTs act as the most prevalent nanocomposite structural element

Review of the impact of the external magnetic field on the characteristics of magnetic nanofluids

The emergence of nanofluids as high-efficiency thermal transfer media has piqued the curiosity of heat transfer researchers. Nanomaterial has since been used in a variety of industries, including manufacturing, electronics and electrical systems, automobiles, and applications in biology. On the other hand, magnetic nanoparticle-suspended nanofluids have sparked tremendous attention due to their numerous technical and industrial applications. Several investigations have looked into how the external magnetic field affects the characteristics of magnetic nanofluids. The magnetization of the nanoparticles, which may increase the nanofluid's effective thermal conductivity, is one of the external magnetic field's most important effects. The viscosity of the nanofluid may additionally be impacted by the magnetization of the nanoparticles, resulting in magnetorheological behavior. The effects of an external magnetic field on nanofluids were studied in this research. The research evaluates the thermal conductivity and viscosity research on magnet nanofluids that rely on magnetism