Electrooxidation of Glucose at Nanoporous Gold Surfaces: Structure Dependent Electrocatalysis and Its Application to Amperometric Detection

Electrooxidation of glucose is investigated at nanoporous gold (NPG) with controlled surface structures by applying different deposition charges during the formation of Ag? Au layers. As the deposition charge increases, the NPG surfaces exhibit smaller ligament/pore structures and the electrocatalytic oxidation of glucose becomes more effective. Voltammetric responses of NPG suggest that the electrocatalytic oxidation arises from the enrichment of (110) or (100) surface orientation of gold with higher deposition charges. The electrooxidation of glucose is retained at NPG surfaces with higher deposition charges in the presence of Cl^?, which suggests possible applications to the amperometric glucose detection in biological samples.     

Synthesis,characterization, and application of novel biodegradable self-assembled 2-(N-phthalimido) ethyl-palmitate nanoparticles for cancer therapy

We report the synthesis of novel biodegradable nanoparticles (NPs) which can kill the cancer cells without any additional drug loading. The NP was a self-assembled form of a phthalimide based conjugate, in which the phthalimide moiety was responsible for the anticancer activity. We describe the synthesis of a novel 2-(N-phthalimido) ethyl palmitate (PHEP-Pal) conjugate and subsequent preparation of NPs by a simple self assembly process. The successful synthesis of conjugate was confirmed by various characterization studies including nuclear magnetic resonance spectroscope, Fourier transform infrared spectroscope, TOF-liquid chromatography mass spectroscope, differential scanning calorimetry, and X-ray diffraction unit. The synthesis, shape, size, and size distribution of PHEP-Pal NPs were determined by transmission electron microscope, atomic force microscope, and dynamic light scattering technique. Finally, cell culture studies using A549 and HeLa cells were done to evaluate the anticancer effect of PHEP-Pal NPs, which demonstrated the potency of these NPs for use in cancer chemotherapy.     

Low-frequency fluctuations in a pure toroidal magnetized plasma

A magnetized, low-β plasma in pure toroidal configuration is formed and extensively studied with ion mass as control parameter. Xenon, krypton and argon plasmas are formed at a fixed toroidal magnetic field of 0.024 T, with a peak density of ∼10¹¹ cm⁻³, ∼4 × 10¹⁰ cm ⁻³ and ∼2 × 10¹⁰ cm ⁻³ respectively. The experimental investigation of time-averaged plasma parameter reveals that their profiles remain insensitive to ion mass and suggests that saturated slab equilibrium is obtained. Low-frequency (LF) coherent fluctuations (ω < ω _ci) are observed and identified as flute modes. Here ω _ci represents ion cyclotron frequency. Our results indicate that these modes get reduced with ion mass. The frequency of the fluctuating mode decreases with increase in the ion mass. Further, an attempt has been made to discuss the theory of flute modes to understand the relevance of some of our experimental observations.     

Diagnostic of capacitively coupled radio frequency plasma by homogeneous discharge model

In this Letter, a plasma diagnostic technique is reported to evaluate the plasma parameters of capacitively coupled radio frequency argon plasma on the basis of homogeneous discharge model. The technique is implemented for wide range of operating pressure ranging from few mTorrs to atmospheric pressure. Considerable dependence of plasma parameters on the plasma series resonance effect and the drift velocity of the electron for low pressure plasma and on the ion density for atmospheric pressure plasma jet were observed.     

A mild and efficient protocol for oxidation of thiols to disulfides in water

A novel vanadium polyoxometalate [(C₇H₇)(CH₃)₃N]₃[H₃V₁₀O₂₈].3H₂O works as a useful oxidant for the oxidation of thiols to disulfldes in water under mild reaction conditions in an excellent yield. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:231–234, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20760     

Free-flowing, transparent γ-alumina nanoparticles synthesized by a supersonic thermal plasma expansion process

Nanoparticles of crystalline, phase-pure γ-alumina is synthesized in a supersonically expanded thermal plasma jet assisted experimental chemical reactor, with good control over the average particle sizes independently with respect to plasma current, oxygen flow rate and the ambient pressure in the sample collection chamber. Most of the synthesized particle samples were seen to be transparent, which gets more transparent with decrease in the particle sizes. The lowest achievable pressure in the chamber had produced particles with average 10 nm sizes, which was best also in terms of narrow size distribution. Another important observation was the absence of serious inter-particle agglomeration, producing free-flowing particles. Optical emission spectroscopic technique was used to study the plasma chemistry of the reaction zone as well as the plasma jet.     

Evolution of structural properties of iron oxide nano particles during temperature treatment from 250 °C-900 °C: X-ray diffraction and Fe K-shell pre-edge X-ray absorption study

Iron oxide nano particles with nominal Fe₂O₃ stoichiometry were synthesized by a wet, soft chemical method with heat treatment temperatures from 250 °C to 900 °C in air. The variation in the structural properties of the nano particles with the heat treatment temperature was studied by X-ray diffraction and Fe K-shell X -ray absorption spectroscopy. X-ray diffractograms show that at lower annealing temperatures the nano particle comprise both maghemite and hematite phases. With increasing temperature, the remainder of the maghemite phase transforms completely to hematite. Profile analysis of the leading Bragg reflections reveals that the average crystallite size increases from 50 nm to 150 nm with increasing temperature. The mean primary particle size decreases from 105 nm to 90 nm with increasing heat treatment temperature. The X-ray diffraction results are paralleled by systematic changes in the pre-edge structure of the Fe K-edge X-ray absorption spectra, in particular by a gradual decrease of the t_2g/e_g peak height ratio of the two leading pre-edge resonances, confirming oxidation of the Fe from Fe²⁺ towards Fe³⁺. Transmission electron microscopy (TEM) on the samples treated at temperatures as high as 900 °C showed particles with prismatic morphology along with the formation of stacking fault like defects. High resolution TEM with selected area electron diffraction (SAED) of samples heat treated above 350 °C showed that the nano particles have well developed lattice fringes corresponding to that of (110) plane of hematite.     

Effect of ambient air pressure on synthesis of copper and copper oxide nanoparticles by wire explosion process

Nanoparticles of copper and copper oxide were synthesized by wire explosion technique in the environment of different ambient air pressure. Copper wire with a diameter of 125 μm and 6.1 cm in length has been exploded in air at 1 bar, 500 mbar, 100 mbar and 50 mbar. Current density in the order of 10⁶ A cm⁻² has been applied to disintegrate the wire by discharging a 1.85 μF capacitor at 10 kV. It is found that the particle size distribution for nano-sized particles follows the log-normal distribution and the median diameter is found to decrease from 31.3 nm to 23.6 nm as the pressure is decreased from 1 bar to 50 mbar.     

Biological Components and Bioelectronic Interfaces of Water Splitting Photoelectrodes for Solar Hydrogen Production

Artificial photosynthesis (AP) is inspired by photosynthesis in nature. In AP, solar hydrogen can be produced by water splitting in photoelectrochemical cells (PEC). The necessary photoelectrodes are inorganic semiconductors. Light‐harvesting proteins and biocatalysts can be coupled with these photoelectrodes and thus form bioelectronic interfaces. We expand this concept toward PEC devices with vital bio‐organic components and interfaces, and their integration into the built environment.