Biosynthesis of Highly Dispersed Palladium Nanoparticles Using Astraglmanna Aqueous Extract

Biosynthesis of nanoparticles has received increased attention due to a growing need to develop environmentally benign technologies in material synthesis and employment of secondary metabolites from plant extract that has emerged as a novel technology for this purpose. In this study, a rapid and biogenic process for fabrication of palladium nanoparticles (PdNPs) is reported. Highly dispersed palladium nanoparticles were successfully prepared by using aqueous extract of Astraglmanna, a non‐toxic and eco‐friendly material, without extra surfactant, capping agent, and template. The PdNPs were characterized by using UV—Visible spectroscopy, scanning electron microscope ‐ energy dispersive spectra (SEM‐EDX), Fourier transform infra red spectroscopy (FTIR), dynamic light scattering (DLS) and X‐ray diffraction (XRD) analysis. Transmission electron microscopic (TEM) images of the PdNPs were recorded and mean size of the biosynthesized nanoparticles was found to be approximately 15 nm.     

A Turn Off Fluorescence Probe Based on Carbon Dots for Highly Sensitive Detection of BRCA1 Gene in Real Samples and Cellular Imaging

Journal of Fluorescence - In this research, DNA-modified carbon dots (CDs) were exploited to construct a fluorescence assay for breast cancer genes (BRCA1, a potential marker for cancer diagnosis)...     

Unsteady flows of inhomogeneous incompressible fluids

In this paper, we study the unsteady motion of inhomogeneous incompressible viscous fluids. We present the results corresponding to Stokes' second problem and for the flow between two parallel plates where one is oscillating.     

Silver nanoparticles‐tragacanth gel as a green membrane for effective extraction and determination of capecitabine

A novel eco‐friendly and effective electromembrane extraction method combining high‐performance liquid chromatography with UV detection was developed for the enrichment and determination of capecitabine. Tragacanth‐silver nanoparticles conjugated gel was prepared by dissolving the tragacanth powder in synthesized silver nanoparticles solution and was used as a green membrane in electromembrane extraction. The porosity and presence of silver nanoparticles in the gel were characterized by field emission scanning electron microscopy. This new electromembrane extraction approach uses neither organic solvent nor carrier agents to extract the target analyte. The best electromembrane extraction efficiency was obtained by using 4.0 mm membrane gel thickness containing 2.5% w/v of tragacanth gum, donor phase pH = 5.0, acceptor phase pH = 3.0, applied voltage 50 V, extraction time 20 min, and agitation rate 500 rpm. During method validation under the optimized conditions, good linearity dynamic range between 1 and 500 ng/mL with the coefficient of determination (R²) = 0.998 was obtained. Limit of detection and Limit of quantitation were estimated to be 0.84 and 1.0 ng/mL, respectively. Finally, the applicability of this method in real samples was confirmed by an acceptable performance in extraction and determination of capecitabine in human plasma samples.     

Theoretical studies on the rotamers and dynamic behaviors of ethyl-5-acetyl-4-(3′,4′-dimethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3-carboxylate

The potential energy surfaces of ethyl-5-acetyl-4-(3′,4′-dimethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3-carboxylate have been explored by density functional theory B3LYP with 6-31G* basis set method. All minima and maxima points have a flat boat conformation and the aryl ring lies above the 1,4-dihydropyridine ring. Therefore, the rotation of aryl, acetyl, and carboethoxy groups do not cause a major conformational change in this compound. However, the orientations of carbonyl groups and the distortion from planarity of dihydropyridine ring have been changed. Intramolecular H-contacts involving CH-groups as proton donors have also been investigated. Comparative analysis of the results indicates that the barrier to rotation for aryl group is smaller than that of the carbonyl groups. In addition, the barriers to rotation for the carbonyl and aryl groups of the corresponding pyridine, i.e., ethyl-5-acetyl-4-(3′,4′-dimethoxyphenyl)-2,6-dimethyl-pyridine-3-carboxylate, have also been computed by a similar basis set to investigate the effect of aromaticity of the dihydropyridine ring on the these parameters.     

New rac‐XP(O)(OC6H5)(NHC6H4‐p‐CH3) [X = N(CH3)(cyclo‐C6H11) and NH(C3H5)] and rac‐(C6H5CH2NH)P(O)(OC6H5)(NH‐cyclo‐C6H11) mixed‐amide phosphinates

The mixed‐amide phosphinates, rac‐phenyl (N‐methylcyclohexylamido)(p‐tolylamido)phosphinate, C₂₀H₂₇N₂O₂P, (I), and rac‐phenyl (allylamido)(p‐tolylamido)phosphinate, C₁₆H₁₉N₂O₂P, (II), were synthesized from the racemic phosphorus–chlorine compound (R,S)‐(Cl)P(O)(OC₆H₅)(NHC₆H₄‐p‐CH₃). Furthermore, the phosphorus–chlorine compound ClP(O)(OC₆H₅)(NH‐cyclo‐C₆H₁₁) was synthesized for the first time and used for the synthesis of rac‐phenyl (benzylamido)(cyclohexylamido)phosphinate, C₁₉H₂₅N₂O₂P, (III). The strategies for the synthesis of racemic mixed‐amide phosphinates are discussed. The P atom in each compound is in a distorted tetrahedral (N¹)P(=O)(O)(N²) environment. In (I) and (II), the p‐tolylamido substituent makes a longer P—N bond than those involving the N‐methylcyclohexylamido and allylamido substituents. In (III), the differences between the P—N bond lengths involving the cyclohexylamido and benzylamido substituents are not significant. In all three structures, the phosphoryl O atom takes part with the N—H unit in hydrogen‐bonding interactions, viz. an N—H...O=P hydrogen bond for (I) and (N—H)(N—H)...O=P hydrogen bonds for (II) and (III), building linear arrangements along [001] for (I) and along [010] for (III), and a ladder arrangement along [100] for (II).     

Zitterbewegung in External Magnetic Field: Classic versus Quantum Approach

We investigate variations of the Zitterbewegung frequency of electron due to an external static and uniform magnetic field employing the expectation value quantum approach, and compare our results with the classical model of spinning particles. We demonstrate that these two so far compatible approaches are not in agreement in the presence of an external uniform static magnetic field, in which the classical approach breaks the usual symmetry of free particles and antiparticles states, i.e. it leads to CP violation. Hence, regarding the Zitterbewegung frequency of electron, the classical approach in the presence of an external magnetic field is unlikely to correctly describe the spin of electron, while the quantum approach does, as expected. We also show that the results obtained via the expectation value are in close agreement with the quantum approach of the Heisenberg picture derived in the literature. However, the method we use is capable of being compared with the classical approach regarding the spin aspects. The classical interpretation of spin produced by the altered Zitterbewegung frequency, in the presence of an external magnetic field, are discussed.     

Synthesis of narrow size distribution sub-micron TiO2 spheres

Ultra-fine spheres of TiO₂ are synthesized through sol-gel colloidal processing. Compared to previous studies, the present work shows a considerable achievement in controlling the shape of the produced particles as well as a relatively narrow size distribution.     

The influence of different factors on the stability and ultrafiltration of emulsified oil in water

The effects of different operating conditions on ultrafiltration (regenerated cellulose with a cut-off of 100 kg/mol) of cutting oil were studied for two different cases. The factors, examined at three levels, included: pH, oil concentration, feed flow velocity, and temperature. The salt (NaCl and CaCl₂) concentration was examined at three levels as well. A lower concentration range was used initially and was increased in the second case.