Construction of an optical tweezer for nanometer scale rheology

The optical tweezer is a versatile set-up that can be employed in a wide variety of studies investigating the microscopic properties of materials. In particular, this set-up has in recent times been gainfully employed in probing rheological properties of materials that exhibit viscoelasticity. These measurements can provide data at the micro and nanometer scales, not normally accessible by rheometers that are used for measurements on bulk samples. In this work we describe a single laser beam optical tweezer set-up, which is built around an inverted open microscope. The trapped polystyrene particle bead’s deviation from the trap potential minimum is monitored by laser backscattering technique and the bead position measured by a quadrant photodiode detector. Additionally, a provision is made for video microscopic studies on dispersed beads using a CCD camera. A single particle microrheological experiment that can be performed using the set-up is described with relevant calculations.     

ZnO: An Ecofriendly,Green Nano‐catalyst for the Synthesis of Pyrazole Derivatives under Aqueous Media

An efficient nano ZnO catalyzed green protocol for the synthesis of pyrazol derivatives by condensation of different substituted phenyl hydrazines/semicarbazide/thiosemicarbazide with 1,3‐diketone/ketoester at ambient temperature has been achieved. ZnO nanocatalyst was prepared by low temperature solution combustion method. From the Scherrer method the crystallite size of ZnO was estimated and found to be in the range of 30–50 nm. The main advantage of this protocol is an excellent yield, short reaction time and easy work up procedure. The catalyst was found to be reusable up to five catalytic cycles without any appreciable loss in activity of the catalyst.     

Dynamic programming—neural network real-time traffic adaptive signal control algorithm

In this paper, an “intelligent” isolated intersection control system was developed. The developed “intelligent” system makes “real time” decisions as to whether to extend (and how much) current green time. The model developed is based on the combination of the dynamic programming and neural networks. Many tests show that the outcome (the extension of the green time) of the proposed neural network is nearly equal to the best solution. Practically negligible CPU times were achieved, and were thus absolutely acceptable for the “real time” application of the developed algorithm.     

Polyelectrolyte templated polymerization in langmuir films: nanoscopic control of polymer chain organization

Polyelectrolytes introduced in the aqueous subphase are shown to have a profound impact on the kinetics of polymerization of N-octadecylaniline at the air/water interface. This can be attributed to changes effected in molecular organization and reorientation behavior in the Langmuir film. The polyelectrolyte templates lead to considerable modification of the morphology of the monomer and polymer Langmuir films. Polyelectrolyte complexation is found to be an elegant and efficient methodology to achieve enhanced alignment of the polyaniline chains in the transferred Langmuir-Blodgett (Langmuir-Schafer) film.     

Transient ζ‐potential measurements in hydrophobic,TOPAS microfluidic substrates

We utilize time‐resolved electrokinetic measurements in order to study the electrokinetic properties of silica and TOPAS microfluidic channels as a function of the time history of the fluid–solid interface. In pressure‐driven flow through TOPAS microchannels, the ζ‐potential as inferred from streaming potential measurements decays exponentially by a factor of 1.5 with a characteristic decay time of 3 h after the initial formation of the fluid–solid interface. A similar exponential decay is observed immediately after water is exchanged for ethanol as the solvent in the system. In electroosmotically driven flow through TOPAS microchannels, the ζ‐potential as inferred through current monitoring experiments was constant in time. No electrokinetic transients were observed in silica microchannels under these flow conditions.     

Synthesis of Tri‐functional Core‐shell CuO@carbon Quantum Dots@carbon Hollow Nanospheres Heterostructure for Non‐enzymatic H2O2 Sensing and Overall Water Splitting Applications

A core‐shell structure with CuO core and carbon quantum dots (CQDs) and carbon hollow nanospheres (CHNS) shell was prepared through facile in‐situ hydrothermal process. The composite was used for non‐enzymatic hydrogen peroxide sensing and electrochemical overall water splitting. The core‐shell structure was established from the transmission electron microscopy image analysis. Raman and UV‐Vis spectroscopy analysis confirmed the interaction between CuO and CQDs. The electrochemical studies showed the limit of detection and sensitivity of the prepared composite as 2.4 nM and 56.72 μA μM^?1 cm^?2, respectively. The core‐shell structure facilitated better charge transportation which in turn exhibited elevated electro‐catalysis towards hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting. The overpotential of 159 mV was required to achieve 10 mA cm^?2 current density for HER and an overpotential of 322 mV was required to achieve 10 mA cm^?2 current density for OER in 1.0 M KOH. A two‐electrode system was constructed for overall water splitting reaction, which showed 10 and 50 mA cm^?2 current density at 1.83 and 1.96 V, respectively. The prepared CuO@CQDs@CHNS catalyst demonstrated excellent robustness in HER and OER catalyzing condition along with overall water splitting reaction. Therefore, the CuO@CQDs@CHNS could be considered as promising electro‐catalyst for H₂O₂ sensing, HER, OER and overall water splitting.     

Synthesis,Antitubercular Activity,and Molecular Docking Studies of Novel 2-(4-Chlorobenzylamino)-4-(cyclohexylmethylamino)-pyrimidine-5-carboxamides

Russian Journal of General Chemistry - A novel series of 2-(4-chlorobenzylamino)-4-(cyclohexylmethylamino)-pyrimidine-5-carboxamide derivatives are synthesized and their structures are confirmed by...     

Synthesis and Anticancer Activity of Thiophene-2-carboxamide Derivatives and In Silico Docking Studies

Russian Journal of General Chemistry - A novel series of thiophene-2-carboxamide derivatives are designed and synthesized, and their structures are confirmed by 1H and 13C NMR, and mass spectra....     

Composition-Space Behavior of Diffusion-Reaction Systems

Species concentrations in homogeneous well-stirred reacting (WSR) systems with multiple time scales mostly access only a small portion (slow manifold) of the permitted composition space. This offers a mathematically sound basis for reducing complex kinetics. Computational investigation of such slow manifolds in inhomogeneous reaction systems undergoing diffusion in addition to chemical reaction is the subject of this paper. We perform simulations of a one-dimensional diffusion–reaction system from random non-premixed initial conditions to study the accessed composition space for a variety of diffusion to reaction time scale ratios. A detailed hydrogen–oxygen chemical kinetic set (6 species, 14 reactions) is used. Our results show that, to first order, the effect of random advection and diffusion is merely to increase the accessed state-space dimensionality over that of the WSR by the number of relevant mixture fractions. Circumstances under which the above simplification is not accurate are also identified.