Highly sensitive non-enzymatic glucose sensor based on copper oxide nanorods

Journal of Nanoparticle Research - Highly sensitive low-cost non-enzymatic glucose sensor of copper oxide (CuO) nanorods (NRs) was successfully fabricated using a two-step anodization method with...     

Morphologically Divergent Development of SnS Photocatalysts from Under-Utilized Ionic Precursors of SILAR Process

Journal of Cluster Science - Successive ionic layer adsorption and reaction (SILAR) process has been diversely used for deposition of various metal chalcogenides. SnS is one of them. Owing to the...     

Synthesis of new 4-methyl-3-piperidones via an iron-catalyzed intramolecular tandem isomerization–aldolisation process

A new versatile synthesis of 3-piperidones is described, starting from amino acids. It uses, as a key step, an iron carbonyl-mediated intramolecular tandem isomerization–aldolisation reaction. These new heterocycles appear as useful scaffolds for the total synthesis of various types of bioactive molecules.     

Modeling of Breakthrough Curves for Adsorption of Propane, <Emphasis Type=Italic>n</Emphasis>-Butane,and Iso-Butane Mixture on 5A Molecular Sieve Zeolite

Breakthrough curves for the adsorption of propane, n-butane, and iso-butane mixture on 5A molecular sieve zeolite were obtained experimentally and theoretically at a constant temperature of 301 K. The equilibrium model and linear driving force model were used to predict the experimental breakthrough curves for this multicomponent mixture. The equilibrium model gave a satisfactory fit for experimental data. The model equations were solved by a numerical method based on backward finite difference with a fixed griding technique. The effects of feed flow rate (0.552–3.496 l/min), feed concentration (60.72–141.68 mmol/l), and adsorbates composition (58.75–75.32%) on these breakthrough curves were examined.     

Total synthesis of gabosines via an iron-catalyzed intramolecular tandem aldol process

Several gabosines, belonging to polyhydroxy-cyclohexenone and cyclohexanone class of natural products, are synthesized in various stereoforms using an intramolecular iron-catalyzed tandem aldol process. The reaction, which starts from vinylic pyranoses, is compatible with two different OH protecting groups (acetyl and benzyl). Further, like the Ferrier carbocyclisation, it is not sensitive to the stereochemistry of sugar molecules used as precursors: six different gabosine-type molecules have been prepared by this route starting from d-Glucose, d-Mannose, and d-Galactose derivatives.     

Preparation and characterization of a new sol–gel hybrid based tetraethoxysilane-polydimethylsiloxane as a stir bar extraction sorbent materials

A new tetraethoxysilane-polydimethylsiloxane (TEOS-PDMS) for use as sorbent of stir bar sorptive extraction (SBSE) towards two selected organophosphorus pesticides (OPPs) namely chlorpyrifos and malathion was successfully synthesized through sol–gel technology. Four different molar ratios of TEOS:PDMS (1:1, 2:1, 3:1 and 4:1) sol solutions were prepared and dipped coated onto the surface of a glass-encased stir bar. Extraction efficiency of the prepared coatings towards the two selected OPPs were compared. A number of factors have been found to greatly affect the characteristics and properties of a particular sol–gel coating. Hence, in this study, several sol–gel coating conditions have been optimized using the optimized molar ratio 3:1 TEOS:PDMS to obtain the best coating as the stationary phase for SBSE. The raw OH-TPDMS and TEOS were characterized using Fourier Transform Infrared Spectroscopy (FT-IR) and compared with spectra of the four different molar ratios of TEOS:PDMS. The FT-IR spectrum of TEOS:PDMS showed the co-polymerization between PDMS and hydrolyzed TEOS molecules demonstrating the formation of the hybrid network in the sol–gel hybrid material. Surface morphology of hybrid sol–gel TEOS-PDMS with optimized molar ratio of 3:1 TEOS:PDMS were examined using FE-SEM. The surface of the sol–gel coating seems to be rough and homogeneous. The more rough structure formed by the 3:1 molar ratio TEOS:PDMS provides enhanced surface area which in turn improved sample capacity or adsorption process.     

Bis[2,2′-ethylenedioxydibenzaldehyde bis(thiocarbohydrazide)] tris(pyridine) solvate

The title compound, a novel 30-membered 2:2 macrocyclic thio­carbohydrazone, C₃₄H₃₂N₈O₄S₂·3C₅H₅N, has been pre­pared and crystallographically characterized. The mol­ecule of the compound is twisted. One dioxa­butane group is boat-like in shape, whereas the other is highly disordered. The crystal structure is stabilized by inter- and intramolecular hydrogen bonds.     

Reverse-engineering of polynomial dynamical systems

Multivariate polynomial dynamical systems over finite fields have been studied in several contexts, including engineering and mathematical biology. An important problem is to construct models of such systems from a partial specification of dynamic properties, e.g., from a collection of state transition measurements. Here, we consider static models, which are directed graphs that represent the causal relationships between system variables, so-called wiring diagrams. This paper contains an algorithm which computes all possible minimal wiring diagrams for a given set of state transition measurements. The paper also contains several statistical measures for model selection. The algorithm uses primary decomposition of monomial ideals as the principal tool. An application to the reverse-engineering of a gene regulatory network is included. The algorithm and the statistical measures are implemented in Macaulay 2, and are available from the authors.     

Synthesis,structure determination and chemoselective catalytic studies of amino acids complexes of osmium(II)

The two new half sandwich amino acids complexes of osmium, i.e. [Os(η6‐p‐cymene)(κ1‐N‐(rac)‐phenylglycine methylester)Cl₂] ( A ) and [Os(η6‐p‐cymene)(κ1‐N,N′‐(S)‐phenylalanineamido)Cl] ( B ) have been synthesized and employed for chemoselective reduction of ketones (nine α,β‐unsaturated ketones and three saturated ketones). The complexes were characterized by spectroscopic as well as analytical methods; their solid structures were confirmed by single‐crystal X‐ray analysis. Both of the osmium complexes catalyze the reduction of α,β‐unsaturated ketones to saturated ketones via isomerization of the initially produced allylic alcohols. The reducible substrates were studied to obtain information on the steric and electronic factors which may affect the interaction of the substrate with the metal center and, thus, control the selectivity of the hydrogen‐transfer reductions. Copyright © 2008 John Wiley & Sons, Ltd.     

A coupled boundary element–finite difference model of surface wave motion over a wall turbulent flow

An effective numerical technique is presented to model turbulent motion of a standing surface wave in a tank. The equations of motion for turbulent boundary layers at the solid surfaces are coupled with the potential flow in the bulk of the fluid, and a mixed BEM–finite difference technique is used to model the wave motion and the corresponding boundary layer flow. A mixing‐length theory is used for turbulence modelling. The model results are in good agreement with previous physical and numerical experiments. Although the technique is presented for a standing surface wave, it can be easily applied to other free surface problems. Copyright © 2005 John Wiley & Sons, Ltd.