International Journal of Nanoscience

Magnetite nanoparticles are extensively studied for their applications in magnetic nanoparticle hyperthermia. However, existing methods involve invasive methods for monitoring the thermal profile while the heat generated by the magnetite nanoparticles is utilized for cancer therapy. Tumor diagnosis utilizing thermography for monitoring the thermal profile is in the early stage of development since the temperature sensitivity is influenced by various experimental factors. Magnetite nanoparticles embedded in agar matrix which mimics the human tissues and their heating characteristics were investigated using infrared thermography. The magnetite nanoparticles with an average particle size of 10nm were subjected to heating in an applied frequency of 500kHz. The influence of concentration, area and depth on the heating characteristics of the tumor phantoms were deduced from the thermography images. The parameters that influence the therapeutical sensitivity while using infrared thermography for magnetic nanoparticle hyperthermia, have been studied for potential applications in theranostics.

Objectives: Over the last decades, antineoplastic drugs have resulted in concerns about health care and pharmacy because of the increased incidence of neoplasm due to occupational exposure. Therefore, there is a need for accurate and valid methods to detect and evaluate the trace amount of these drugs in occupational assessment programs. In this study, for occupational exposure assessment of 5-fluorouracil (5-FU), molecularly imprinted membranes (MIMs) were synthesized and optimized as appropriate absorbents for selective determination of trace amount of this antineoplastic drug.

Methods: To synthesize MIMs as Specific adsorbent for 5-FU, First, 5-FU molecularly imprinted polymers (MIPs) were prepared by the precipitation polymerization method, and then MIPs encapsulated into PET nanofibers, as the matrix polymer, by electrospinning. Finally, MIMs were fabricated from collection nanofibers. Optimization of electrospinning parameters (e.g., MIP amount, tip needle to the collector, electrospinning voltage and flow rate) was performed by the Central Composite Design (CCD) method using the experimental design software. The diameter of the fiber was analyzed using image analysis software. The applicability of the synthesized membranes for absorbing 5-FU drug was evaluated for assessing occupational exposure to the drug of interest. Results: In this study, MIP particles were successfully encapsulated into PET nanofibers. The optimization process showed that the molecularly imprinted nanofibers diameter of 276.38nm could be obtained in 57.4%w, 13.9cm, 25KV and 0.55ml/h. The extraction efficacy of 5-FU drugs by synthesized membranes was $97.2\pm 0.34$. Conclusion: The optimized MIMs presented in this study can be used as a specific absorbent for occupational and environmental monitoring of the 5-FU drug.

The NiTiO₃ ceramic was synthesized in nanostructured form by citrate gel method. The phase structure, microstructure and magnetic properties of synthesized compounds were investigated by X-ray diffraction (XRD), scanning electron microscope and vibrating sample magnetometer. Williamson–Hall plot was used to calculate the crystallite size and microstrain of sample. The XRD analysis showed the formation of rhombohedral crystal structure of synthesized powders. The crystallite size is about 35nm and microstrain is $5.9\times 10^{-4}$. The optical band gap was estimated from UV-Visible spectrum with value of 2.43eV. The NiTiO₃ samples showed coexistence of ferroelectric and antiferromagnetic properties at room temperature.

This work presents the results of pulsed plasma-chemical modification of silicon dioxide nanopowder with zinc oxide nanoparticles (ZnO@SiO₂). The obtained ZnO@SiO₂ powders were characterized by transmission electron microscopy (TEM) and X-ray phase analysis. The size of the synthesized particles was in the range of 20–100nm. The photocatalytic characteristics of ZnO@SiO₂ were studied. When exposed to ultraviolet radiation, the methylene blue (MB) decomposes efficiently. Two samples characterized by the content of silicon tetrachloride in the initial mixture were synthesized. The band gap estimated from the absorption spectra calculated from the diffuse reflectance spectra for these samples was 2.4eV and 2.95eV for indirect transitions and 3.03eV and 3.24eV for direct allowed transitions.

In this paper, we perform the increase of cut-off frequency for a HEMT based on the InP substrate by the use of a new concept which can be presented by the use of a Multi-Channel (M-Ch) based on InAs${}_{0.3}$P${}_{0.7}$/InP. This concept leads to formation of two confining interfaces and also an added barrier in the channel level which in turn leads to enhance the confining conditions of charge carriers. The obtained cut-off frequency for the proposed HEMT based on InAs${}_{0.3}$P${}_{0.7}$/InP has reached the Tera-hertz range which is the best of all existing power technologies. This morphology of structure is the first power structure that has reached this frequency range due to the use of InAs${}_{0.3}$P${}_{0.7}$ as the main channel, it has better transport proprieties compared to that of InP. The same task is for the drain current in which the proposed structure has shown a high value compared to the structure based on a single-channel (S-Ch) formed by InP due to increasing confining interface number where the booth interface InAlAs/InAsP and InAsP/InP are being used.

In the framework of the density functional theory and method of nonequilibrium Green functions (DFT $+$ NEGF), the electric transport properties of the model nanojunction “Graphene–Fullerene C${}_{60}$–Graphene” were studied. The transmission spectra, the density of states, the current–voltage characteristic (CVC) and the differential conductivity of the nanojunction are determined. The appearance of a feature of the DOS nanotransition is revealed. This is due to the fact that the Lowest Unoccupied Molecular Orbital (LUMO) of C${}_{60}$ becomes closer to the Fermi level of metal substrates than its Highest Occupied Molecular Orbital (HOMO). It is shown that Coulomb stairs associated with the Coulomb blockade effect appear on the CVC of the nanotransition. The same changes are observed on the differential conductivity spectrum in the form of eight distinct peak structures arising with period $\mathrm{\Delta }V\approx 0.683$V. The comparison of the electric transport characteristics of single-fullerene nanodevices with various electrode materials (graphene, gold, platinum) are presented. It was found that the voltage period of Coulomb features $\mathrm{\Delta }V$ in a nanodevice with graphene electrodes is less than in nanodevices with platinum and gold electrodes. It was revealed that the considered nanotransition has negative differential conductivity. The results obtained can be useful in calculating promising elements of single-electronics.

Nitration of aromatic compounds is an important industrial process, which creates significant environmental pollution because of the harsh mineral acid catalysts. In this work, we report the synthesis and application of magnetic iron oxide nanoparticles as green catalysts for aromatic nitration. Magnetic iron oxide nanoparticles were synthesized by co-precipitation method and tested for nitration reactions on selected aromatic substrates, phenol, benzaldehyde, methylbenzoate, $o$-cresol and $p$-cresol. For the nitration reactions, sodium nitrite was used as the nitro-source and hydrogen peroxide as the oxidant. Effect of reaction conditions like, solvent, temperature and microwave treatment were studied. The magnetic nanoparticles were found to be more stable after coating with a carbon shell by a one-pot carbonization method. The reactions were fast with good product yield under solvent-free microwave conditions. The nano-catalyst was recovered magnetically after the reaction and reused for three batches of nitration, without significant loss in catalytic activity. The nanoparticles were characterized using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometry (XRD) and FTIR spectroscopy.

This paper highlights on the coronavirus outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At the time of writing this paper, there has been over 6 million confirmed cases worldwide. It is a person–person transmittable infection but there have been cases of asymptomatic carriers. Hence, development of an effective biosensing diagnostic tool can curb its rapid transmission rate. The first part of the paper highlights on the SARS-CoV-2 structure and its resemblance to SARS-CoV. The second part of the paper analyzes on the potential application of gold and silver nanoparticles to generate a red shift that had enhanced the calorimetric property of the MERS-CoV analysis due to transition in its optical property. Other electrochemical techniques that utilized the application of gold nanoparticles are also reviewed. Gold and silver nanoparticles (AuNP and Ag NP) can accelerate the sensitivity upon electrodeposition on the diagnostic tool.

Stated work consisted synthesis of ZnO nanoparticles (NPs) by the irradiation of microwaves. Material is formed by a simple chemical precipitation method by using Zinc Acetate Dehydrate (Zn(CH₃COO)₂$\cdot$2H₂O) and Sodium hydroxide (NaOH) as base chemicals in aqueous media for two different pH (12 and 14) values. This synthesis was carried out at room temperature. Synthesized NPs are dried in Microwave oven for 3 min of duration each. X-ray Diffraction (XRD) study confirmed the trend of incremental crystallinity upon increasing pH. XRD reveals the existence of (100), (002), (101), (102) and (110) reflections at $32.7^{\circ }$, $35.3^{\circ }$, $37.2^{\circ }$, $48.4^{\circ }$ and $57.4^{\circ }$ two theta values, respectively. Crystallite size was determined by both Scherrer formula and W–H plot method. UV-Vis spectroscopy is utilized to probe the optical features of ZnO NPs. This confirms intrinsic excitonic transition properties of ZnO. UV absorbance shows decrement upon increasing pH value. Band gap depicts the decremental behavior upon increasing pH. Stated method is a novel and time saving method for ZnO NPs synthesis; a large scale production is also feasible by this method.

The impact of hydrogen on the conductivity and vibration for zinc oxide (ZnO) nanoparticles had implicated for nanoscale optoelectronic units. Infrared reflectance spectra for ZnO hydrogen-annealed nanoparticles were calculated at incidence. The theory of density functional theory is applied to the reflectance model and absorption spectra. There is an agreement between both the model suggesting that the nanoparticles have inhomogeneous carriers’ concentrations and the experimental results. A significant decrease in carrier concentration resulted from exposure to oxygen for several hours, according to the adsorption on the nanoparticle surface of negative oxygen molecules. Also, the density of states in deferent wurtzoid’s size has been studied. The experimental energy gap values of bulk ZnO, HOMO and LUMO levels as a function of the total Zn and O atoms number in ZnOH diamondoids were determined, as well as the bond length in deferent wurtzoid’s size where the experimental ZnO bond length at 1.9767 Å has been calculated. The tetrahedral angles in deferent wurtzoid’s size were studied, deferent wurtzoid’s size Reduced mass as a vibration frequency function and force constant as a function of vibrational frequency in deferent wurtzoid’s size were determined. A good result for infrared as a vibration frequency function in deferent wurtzoid’s size has been found, as well as Raman as a vibration frequency function in deferent wurtzoid’s size.