Current Nanoscience - Volume 19, Issue 1, 2023

Background: This article numerically examines the effect of buoyancy and Marangoni convection in a porous enclosure formed by two concentric cylinders filled with Ag-MgO water hybrid nanofluid. The inner wall of the cavity is maintained at a hot temperature, and the outer vertical wall is considered to be cold. The adiabatic condition is assumed for the other two boundaries. The effect of the magnetic field is considered in radial and axial directions. The Brinkman-extended Darcy model has been adopted in the governing equations. Methods: The finite difference scheme is employed to work out the governing Navier-Stokes equations. The numerically simulated outputs are deliberated in terms of isotherms, streamlines, velocityand average Nusselt number profiles for numerous governing parameters. Results: Except for a greater magnitude of axial magnetic field, our results suggest that the rate of thermal transport accelerates as the nanoparticle volume fraction grows. Also, it is observed that there is an escalation in the profile of average Nusselt numberwith an enhancement in Marangoni number. Conclusion: Furthermore, the suppression of heat and fluid flow in the tall annulus is mainly due to the radial magnetic field whereas in the shallow annulus, the axial magnetic field profoundly affects the flow field and thermal transfer.

Background: The radiative magnetohydrodynamic (MHD) flow of an incompressible viscous electrically conducting hybrid nanofluid over an exponentially accelerated vertical surface under the influence of slip velocity in a rotating frame taking Hall and ion slip impacts is discussed. Methods: Water and ethylene glycol mixture have been considered as a base fluid. A steady homogeneous magnetic field is applied under the assumption of a low magnetic Reynolds number. The ramped temperature and time-varying concentration at the surface are taken into consideration. The first-order consistent chemical reaction and heat absorption are also regarded. Silver (Ag) and titania (TiO2) nanoparticles are disseminated in base fluid water and ethylene glycol mixture to be formed a hybrid nanofluid. The Laplace transformation technique is employed on the non-dimensional governing equations for the closed form solutions. Results: The phrases for non-dimensional shear stresses, rates of heat, and mass transfer are also evaluated. The graphical representations are presented to scrutinize the effects of physical parameters on the significantflow characteristics. The computational values of the shear stresses, rates of heat and mass transports near the surface are tabulated by a range of implanted parameters. Conclusion: The resultant velocity grows by an increase in thermal and concentration buoyancy forces, Hall and ion-slip parameters, whereas rotation and slip parameters have overturn outcome on them. The temperature of hybrid Ag-TiO2/WEG nanofluid is relatively superior to that of Ag-WEG nanofluid. Species concentration of hybrid Ag-TiO2/WEG nanofluid decreases due to an increase in Schmidt number and chemical reaction parameter.

Background: Superparamagnetic Iron Oxide Nanoparticles (SPIONs) were synthesized by the thermal decomposition method. Methods: In this work, the properties of the nanoparticles synthesized at different reaction times were investigated. Fourier Transformed Infrared Spectroscopy (FTIR) and thermal analysis were carried out to characterize oleate adsorbed on the surface of nanoparticles. Results: The oleate-coated surfaces were obtained for all samples, and the amount of oleate on the surfaces of the particles changed with the change in reaction time. The size, size distribution, and shape of SPIONs were determined by X-ray Diffraction (XRD), transmission electron microscopy (SEM), and Dynamic Light Scattering (DLS). It was seen that changing the reaction time affected the shape of the nanoparticles, but almost the same sized nanoparticles were obtained with the increase of reaction time. The sample's crystallite size of 12.5-14.2 nm achieved with XRD is in good agreement with the mean size of 15-16.4 that was obtained by TEM results. Maximum magnetic saturation of the sample was achieved at 3 h reaction time. Conclusion: The magnetic properties of iron oxide nanoparticles were characterized by Electron- Spin Resonance (ESR) and Physical Properties Measurement System (PPMS). All samples showed superparamagnetic behaviors at room temperature.

Objective: A numerical and theoretical study is developed to analyze the combined effect of activation energy and chemical reaction in the flow of nanofluids due to the thin moving needle using the mathematical nanofluid model offered by Buongiorno. A passively controlled nanoparticle volume fraction boundary is assumed rather than actively controlled. Methods: A similarity transformation is utilized to convert the governing partial differential equations to a set of ordinary differential equations which are then solved numerically by Runge-Kutta Shooting Method (RKSM). The physical characteristics of flow, heat and mass transfer are illustrated via graphs and tables for some set of values of governing parameters. Results: In addition, the basic non-linear governing equations are solved analytically using semianalytical technique called Differential transform method (DTM) and the comparison has been made with the numerical and the published results. Conclusion: The present study reveals that the ratio between the needle velocity and the composite velocity brings out to increases the velocity distribution with λ<0. Moreover, the activation energy influences the chemical species to react from the thickness of the concentration layer η=0.6 and the fraction of nanoparticles to the fluid is significantly more away from the needle surface.

Aims: This article is intended to investigate and determine the combined impact of Slip and Hall current on Peristaltic transmission of Magneto-hydrodynamic (MHD) Eyring- Powell fluid. Background: The hall term arises, taking strong force-field under consideration. Velocity, thermal, and concentration slip conditions are applied. The energy equation is modeled by considering the Joule-thermal effect. To observe the non-Newtonian behavior of the fluid, the constitutive equations of Eyring-Powell fluid are encountered. Objective: Flow is studied in a wave frame of reference traveling with the wave's velocity. The mathematical modeling is done by utilizing adequate assumptions of long wavelength and low Reynolds number. Methods: The closed-form solution for momentum, temperature, and concentration distribution is computed analytically using the regular perturbation technique for the small fluid ter(A). Results: Graphical results are presented and discussed in detail to analyze the behavior of sundry parameters on flow quantities (i.e., velocity, temperature, and concentration profile). It is noticed that Powell-Eyring fluid parameters (A,B) have a significant role in the outcomes. Conclusion: The fluid parameter A magnifies the velocity profile, whereas the other fluid parameter B shows the opposite behavior.

Background: Optical luminescence in a composite system with nematic LC 4- octyloxy-4’-cyanobuphenyl (8OCB) and semiconductor quantum dots CdSe/CdS and CdSe/CdS/ZnS has been synthesized by a water-organic method. Methods: Composites have been investigated by means of polarizing microscopy, dynamic light scattering, and measurements of dielectric properties in the frequency range from 20 Hz to 5 MHz. The non-radiative excitation energy transfer from the liquid crystal molecules to the quantum dot in the LC-QD composite is detected by using the luminescence spectroscopy method. Results: This effect as well as the shift of the luminescence band is owing to components’ intermolecular interaction. Conclusion: The optimal concentration of QD in a composite that enhanced luminescence intensity was detected.

Background: The effect of bionanointeractions on graphene-biomolecule nanohybrids is of great interest, since external influences on their structural and surface properties can significantly affect their biological activity. Introduction: The effects of the fatty acid binding with shungite carbon (ShC) nanoparticles on the stability of aqueous dispersions of ShC and the oxidation state of ShC (oxygen-containing groups) were studied using linoleic acid (LA) as an example. Methods: The size and surface charge (ζ -potential) of the ShC-LA associates formed at various LA concentrations in the dispersion were estimated using the dynamic light scattering method and the ultraviolet (UV) absorption spectra of dispersions were taken. Results: The negative ShC charge becomes less negative upon LA binding, depending on LA concentration. The size of ShC upon functionalization by LA molecules does not depend on LA concentration, suggesting the predominance of surface rearrangement of NPs, rather than a change in their global structure. ShC - LA interaction is accompanied by an increase in absorption in the UV spectrum region of conjugated С=С bonds, the reduction of С=Ц#158; groups, sp2 hybridization and bonds in the plane of graphene fragments, the basic structural units of ShC. Conclusion: The results are interpreted in terms of the surface structural effects of LA on ShC that affect variations of the colloid and redox characteristics of ShC in aqueous dispersion.

Background: Thin films of a 5,10,15,20-tetraphenylporphyrin (H2TPP) and its metal complexes (MeTPP, where Me = Co, Cu, Zn, Fe-Cl) were obtained by vacuum thermal evaporation under quasi-equilibrium conditions (hot wall method) and by coating from a toluene solution on various substrates. It was shown that H2TPP, CuTPP and CoTPP have an ability to selforganization into linear structures during crystallization (nanowhiskers, nanowires, or nanorods), regardless of our obtaining method. Methods: FeClTPP and ZnTPP crystallize into planar films with the same preparation technique. Co-deposition with fullerene C60 allows obtaining fullerene crystallites on the surface of tetraphenylporphyrin, subsequently creating the so-called bulk heterojunctions. Results: The possibility of controlling the shape of obtained crystallites by changing technological parameters and substrates has been shown for metal free tetraphenylporphyrin. High degree crystalline ZnTPP and H2TPP films are characterized by a red shift of photoluminescence and absorption spectra under crystallization. Conclusion: A change in the relative intensity of the photoluminescence spectrum maxima of various nature is observed during transition from amorphous to crystalline structure of H2TPP.

Background: Nanocarbon materials are known as highly sensitive gas sensors when compared to common solid-state sensors. This manuscript discusses graphene-based carbon films as materials for a gas sensor operating at near room temperature. Methods: The structural characteristics of graphene-based carbon films on In2O3- and ITO- coated substrates were studied by confocal laser microscopy, SEM, and Raman spectroscopy. Microwave conductivity was measured by using a λ/4 coaxial resonator based on a symmetric two-wire line in the frequency range 0.65 - 1.2 GHz and the temperature range 290-360 K. Results: The results obtained showed that films on In2O3 - and ITO-coated substrates desorb oxygen from the various structural levels of graphene-based carbon, such as crystalline contacts between globular nanoparticles and distorted graphene fragments. A correlation between the size of nanoparticles in films and the desorption temperature was also revealed. Conclusion: Our studies have shown that thin films of natural graphene-based carbon are promising as gas sensors. The possibility of varying characteristic oxygen desorption temperatures on different substrates is discussed.

Food allergy is one of the world's most serious health problems, which needs new and safer approaches to resolve it. The rapid progress of nanotechnology to tackle the problem of food allergen has generated a new hope. Nanoparticles can be used as a unique system to detect allergens. Furthermore, nanotechnology offers allergen-delivery systems based on nanoparticles as potential adjuvants for allergen-specific immunotherapy. In addition, the use of novel adjuvants using nanoparticles provides a harmless and potentially more effective way of treatment for allergic diseases. For therapeutic applications, nanotechnology-based delivery systems provide increased bioavailability and targeted delivery of food allergens. In addition, nano-based allergen-delivery approaches are mainly aimed at devising a novel and promising approach for allergy vaccines. This review discusses the potential role of nanotechnological strategies for detection, drug delivery, and the treatment of allergies.

Objectives: Platelet-, erythrocyte- and plasma-related products are vital for some patients. The main problems with these products are storage lesions, shelf life limitations, and function and quality maintenance. Dendrimers, a well-known group of polymeric nanoparticles, may help overcome these challenges due to their special properties. Methods: This review article, for the first time, comprehensively discusses studies from 2010 to 2022 on the compatibility of positive, negative, neutral, and modified charge dendrimers with each blood product. Moreover, it provides information regarding dendrimers' applications for improving the quality and function of blood products. Results: A total of one hundred and twenty-six studies showed that dendrimers affect blood components depending on their load, size, molecular weight, functional group, concentration, and exposure time. Generally, cationic dendrimers with higher concentrations and molecular weight and larger size showed little hemocompatibility, while anionic or neutral dendrimers with lower concentrations and molecular weight, and small size were more hemocompatible. Further, some modifications of cationic dendrimers were found to improve their compatibility. For erythrocytes, they included PEGylation and thiolation of dendrimers or functionalizing them with cyclic RGD, nmaleyl chitosan, zwitterionic chitosan, prednisolone, or carbohydrates. Additionally, dendrimers functionalized with arginine-birch, lysine-Cbz, polyethylene glycol, polyethylene glycol-cyclic RGD, thiol, TiO2, maltotriose, or streptokinase decreased the platelet toxicity of dendrimers. The dendrimers modified with polyethylene glycol, glucose, and gold nanoparticles showed increased compatibility in the case of albumin products. Moreover, the PAMAM-dendrimer-antibody conjugates had no adverse effect on antibodies. Dendrimers have a wide range of applications, including virus detection kits, synthetic O2 carriers, bacterial nanofilters, drug carriers, anticoagulants, and enhanced blood product storage. Conclusion: It can be concluded that due to the outstanding properties of different types of dendrimers, particularly their manipulability, nanomaterials can be promising to enhance the quality of blood products. Thus, further research in this area is required.

Background: At the end of December 2019, a case of pneumonia of unknown cause was reported in Wuhan, China. A new coronavirus was then identified as the leading cause of this controversial pneumonia, changing how people worldwide live. Although science has achieved significant advances in COVID-19 during the last two years, the world must do much more to prepare for the emergence and development of viruses that may spread rapidly. Methods: This COVID-19 research project proposes a diagnosis component, an adaptive fuzzy neural network technique, serving as a virus-based bio-nano communication network system that can understand the behavior of the biological and nonbiological processes of COVID-19 virusbased disease diagnosis and detect the pandemic at the early stage. The proposed method also integrates multiple new communication technologies, allowing doctors to monitor and test patients remotely. Results: As an outcome of this technique, the receiver biological nanomachines can adjust the 1/0-bit detection threshold according to the viruses previously encountered. This adjustment contributes to the resolution of the intersymbol interference issue caused by residual particles that arrive at the receiver owing to previous bit transmission and reception noise. Diffusionbased coronavirus nanonetwork systems are evaluated using MATLAB simulations that consider each detection strategy’s most crucial characteristics of the communication system environment. The proposed technique’s performance is evaluated in the presence of different noisy channel sources, which demonstrate a significant increase in uncoded bit error rate performance when compared to the previous threshold detection systems. Conclusion: Thus, diffusion-based coronavirus nanonetwork systems can be the future tool to investigate the existence of a specific type of virus that spreads through lung cells in the respiratory system.

Background: The biosynthesis of zinc oxide nanoparticles (ZnO NPs) has received increasing attention in the field of nanotechnology due to their biomedical applications. With this aim, the present study was performed to synthesize biocompatible ZnO NPs using stems, leaves, and inflorescences extracts of the Tephrosia purpurea (T. purpurea) and Heliotropium indicum (H. indicum) medicinal plants. Objective: The objective of this study was to synthesize ZnO NPs from T. purpurea and H. indicum and determine their ability as an alternative for toxic synthetic antioxidants. Methods: The preliminary phytochemical screening of T. purpurea and H. indicum and quantitative determination of phenols and flavonoids were carried out by using spectrophotometric methods. The antioxidant potential of ZnO NPs was assessed through 2,2–diphenyl-1-picrylhydrazyl (DPPH) and phosphomolybdenum assays against butylated hydroxytoluene standard. Results: Qualitative phytochemical analysis of plant extracts confirmed the presence of terpenoids, alkaloids, carbohydrates, tannins, phenols, flavonoids, and proteins. The highest percentage of phenolics (88.3 ± 1.7 mg GAE/g) and flavonoids (727.1 ± 103.5 mg QE/g) was recorded for H. indicum inflorescences and T. purpurea stems. The T. purpurea stems mediated ZnO NPs showed the most potent DPPH radical scavenging capacity of 81.53 ± 0.14% with an IC50 value of 152.38 ± 0.70 μg/mL, while ZnO NPs synthesized using H. indicum inflorescences and T. purpurea stems indicated the highest total antioxidant capacity of 94.71 ± 2.50 and 91.34 ± 1.07%, respectively. Conclusion: The obtained results revealed the significance of T. purpurea and H. indicum as effective stabilizing agents to develop surface protective ZnO NPs, which can be used as promising antioxidants in the biological systems.