Microelectromechanical system‐based biosensor for label‐free detection of human cytomegalovirus

The human cytomegalovirus (HCMV) is an asymptomatic common virus that is typically harmless, but in some cases, it can be life threatening. Thus, there is an urgent need to develop novel diagnostic methods and strengthen the efforts to combat this virus. A microcantilever‐based biosensor functionalised with the UL83‐antibody of HCMV (UL83‐HCMV antibody) has been developed to detect the UL83‐antigen of HCMV (UL83‐HCMV antigen) at different concentrations ranging from 0.3 to 300 ng/ml. The response of the biosensor to the presence of UL83‐HCMV antigen was measured through the shift in resonance frequency before and after antigen–antibody binding. The system shows a low detection limit of 84 pg/ml, which is comparable to traditional sensors, and a detection time of less than 15 min was achieved. The selectivity of the sensor was demonstrated using three different proteins with and without the UL83‐HCMV antigen. The biosensor shows high selectivity for the UL83‐HCMV antigen. Mass loading by the UL83‐HCMV antigen was roughly estimated with a sensitivity of ∼30 fg/Hz. This technique is crucial for the fabrication of portable and low‐cost biosensors that can be used in real‐time monitoring and enables early medical diagnosis.     

Combined Effect of Oblique Ribs and a Nanofluid on the Thermal-Hydraulic Performance of a Corrugated Channel: Numerical Study

Journal of Engineering Physics and Thermophysics - The thermal-hydraulic performance of a ribbed corrugated channel in which a hybrid nanofluid flows was numerically investigated in the wide range...     

Preparation of magnetite and silver poly(2‐acrylamido‐2‐methyl propane sulfonic acid‐co‐acrylamide) nanocomposites for adsorption and catalytic degradation of methylene blue water pollutant

The aim of the present work was to prepare microgel nanocomposites based on silver and magnetite to apply as adsorbents and heterogeneous catalysts for removal of methylene blue (MB) cationic dye from aqueous solution. For this, 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and acrylamide (AAm) monomers were used to prepare AMPS/AAm microgel based on the emulsion technique. Ag and Fe₃O₄ nanoparticles were embedded into the AMPS/AAm microgel using the in situ technique. Their particle sizes, surface charges, crystalline lattice structure, morphology, magnetic properties and thermal stability were investigated. The AMPS/AAm hydrogel nanocomposites were used as an adsorbent to remove MB dye. The AMPS/AAm microgel nanocomposites were tested as catalysts to reduce MB and degrade its chemical structure with heterogeneous Fenton oxidation using Ag and Fe₃O₄ nanocomposites, respectively. This study presents promising data as the prepared materials used as adsorbents and catalysts show competitive features compared with the data presented in the literature. © 2019 Society of Chemical Industry     

Electronic excitation energies of Zn(i)S(i) nanoparticles

The excitation energies of small ZnS nanoclusters characterized in previous studies have been calculated using TDDFT. The relativistic pseudopotentials of Stevens et al have been used, including Zn 4s(2) electrons and S 3s(2) and 3p(4) electrons as valence electrons. Results obtained with these pseudopotentials are compared to those obtained considering also Zn 3s(2)3p(6)3d(10) electrons in the valence part, and demonstrated to be consistent. The results show that spheroid-like bubble structures have absorption energies in the range of 5-5.3?eV for small sizes, which decreases to 5?eV with increasing particle size.     

Rheological and mechanical properties of polypropylene/thermoplastic starch blend

Starch as an inexpensive and renewable source has been used as a filler for environmentally friendly plastics for about two decades. In order to improve the compatibility between hydrophilic starch granules and hydrophobic polypropylene (PP), glycerol used as a plasticizer for starch to enhance the dispersion and the interfacial affinity in thermoplastic starch (TPS)/PP blend. In this study, PP was melt blended with thermoplastic starch (TPS) using a single screw extrusion process and molded using injection molding process to investigate the rheological and mechanical properties of these blends. TPS viscosity measurements were performed on the single screw extruder. Rheological properties were studied using a capillary rheometer and the Bagley’s correction was performed. Mechanical analysis (stress–strain) was performed using Testometric M350-10KN. The rheological properties showed that the viscosity of TPS decreases with increasing glycerol content in TPS. Also, it was found that PP/TPS blends are pseudo plastic in nature and the flow activation energy of the blends is greater than that of PP. Mechanical results showed that strain at break of the blends is lower than that of PP, whereas the Young’s modulus of the blends is higher than that of PP.     

Microwave‐Assisted Synthesis of Magnetic Hydroxyapatite for Removal of Heavy Metals from Groundwater

A simple, fast, and economic methodology to fabricate a highly efficient superparamagnetic Fe₃O₄/hydroxyapatite nanocomposite (MHAP) was successfully developed. Hydroxyapatite was functionalized with magnetite nanoparticles through coprecipitation‐assisted microwave processes to improve the magnetic properties. The synthesized magnetic hybrid adsorbent matrix was investigated by different methods. Transmission electron microscopy demonstrated a good impregnation of Fe₃O₄ on the hydroxyapatite matrix with uniform morphology. Magnetic hysteresis measurement revealed that MHAP nanocomposites exhibit excellent strong, soft‐magnetic properties. The synergistic effect was an evidence for iron and manganese ion removal, enlightening their potentialities in treatment of polluted ground water.     

Electronic and magnetic properties of Fe3?x Cr x Si ordered alloys from first principles

Density functional theory calculations are performed to investigate the electronic and magnetic properties of Fe_3−x Cr _x Si alloys with Cr concentration in the range of 0.25 ≤ x ≤ 2.75. The L2₁ phase is found to be a more stable one in comparison with the A15 phase for x ≤ 1.50 beyond which the A15 phase becomes more stable. Alloys with the stable L2₁ phase are found to be metallic for x ≤ 0.75, however, a half metallic behavior is found at x = 1.00, 1.25, and 1.50 with band gaps of 0.60, 0.24, and 0.21 eV, respectively. In contrast, all A15 structures are found to be metallic. The total magnetic moments are found to decrease for L2₁ phase from 14.4 μ_B/cell at x = 0.25 to zero at x = 2.00 with non-integer values for the metallic structures and integer values for the half-metallic. However, a monotonic decrease is found for the case of A15 phase with values larger than those of L2₁ phase.