Chemical characterization of soda-lime glass samples by in situ current normalised PIGE and conventional INAA methods for forensic applications

Nuclear analytical methods namely in situ current normalised Particle Induced Gamma Ray Emission (PIGE) and conventional Instrumental Neutron Activation Analysis (INAA) were utilized for determining major, minor and trace concentrations of eighteen elements in five soda-lime (automobile) glass samples. Concentration of four major elements (Si, Na, Mg and Al) by PIGE and fourteen elements including ten trace elements by INAA were determined. For forensic application, major elements were used for confirming the class of glass samples, whereas concentration results of trace elements like transition and rare earth elements were utilized for finding similarity or differences among the glass samples.

     

A convenient palladium catalyzed synthesis of symmetric biaryls, biheterocycles and biaryl chiral diamides

A series of symmetrical diamido biaryls has been synthesized in good yield by direct homocoupling of iodoarylbenzamides by palladium-catalysis. No cross product has been isolated from the reaction mixture of two different iodoarylbenzamides under similar conditions. However, only in the case of 2-iodo-N-phenylbenzamide, the intramolecularly coupled product phenanthridone has been isolated as a minor product along with the major intermolecularly coupled product. Biphenyl chiral diamides have been synthesized by this coupling method. This coupling reaction also works well with the reductive dimerization of functionalized heterocyclic compounds. Thus 6,6′-dipivaloylamino-3,3′-bipyridine and 6,6′-dimethyl-2,2′-bipyridine have been efficiently synthesized. In two cases, the X-ray crystal structures have been solved to establish the structures of symmetrical and chiral diamido biaryls and their supramolecular networks.     

Au nanoparticles and polyaniline coated resin beads for simultaneous catalytic oxidation of glucose and colorimetric detection of the product

In this letter, we report the synthesis of Au nanoparticles (NPs) and polyaniline (PANI) on the same cation-exchange resin beads and demonstrate their use in catalyzing the oxidation of glucose to gluconic acid by Au NPs and simultaneously in detecting the formation of the acid by the color change of PANI. The synthesis was carried out by exchanging the cations of the resins with HAuCl4 and anilinuium chloride and then reducing the metal ions by NaBH4 to produce Au NPs followed by polymerization of aniline using H2O2. The green emeraldine salt form of PANI thus obtained was treated with NaOH to be converted to blue emeraldine base before use. The deposition of Au NPs was confirmed by a change in color of the bead, visible spectroscopy, X-ray diffraction, and scanning electron microscopic measurements. On the other hand, the presence of PANI was confirmed by Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopy. The formation of gluconic acid from glucose was confirmed by FTIR spectroscopy. We could detect the presence of glucose of a minimum 1.0 mM concentration in water, using the present method. Our experimental observations demonstrate the possibility of the incorporation of multifunctional components on the surfaces of resins for carrying out a chemical reaction as well as detection of the product.     

Dynamic molecular recognition in the generation of a new crystal-engineering motif: a unique case study of a dicarboxylic acid with a ditopic receptor favouring a polymeric over a dimeric hydrogen-bonded supramolecular complex

A new crystal-engineering motif has been developed where a ditopic receptor 1 shows a novel syn-syn hydrogen-bonded polymeric supramolecular complex (Fig. 4b) (instead of a 1:1 dimeric syn-syn or polymeric syn-anti complex) giving rise to a hydrogen-bonded stair-like polymeric ribbon structure between the binding groups of the receptor pyridine amide and the carboxyl groups of the guest substrate.     

Platinum complexes of diazo ligands. Studies of regioselective aromatic ring amination, oxidative halogen addition and reductive halogen elimination reactions

2-(Arylazo)pyridine ligands, L1a-1c react with the salt K2[PtCl4] to give the mononuclear complexes [PtCl2(L1)](1), which readily react with ArNH2 to yield the monochloro complexes of type [PtCl(L2)](HL2= 2-[(2-(arylamino)phenyl)azo]pyridine)(2) via regioselective ortho-amine fusion at the pendent aryl ring of coordinated L1. Oxidative addition of the electrophiles Y2(Y = Cl, Br, I) to the square-planar platinum(II) complex, has led to syntheses of the corresponding octahedral platinum(IV) complexes, [PtY3(L2)](3) in high yields. Ascorbate ion reductions of the platinum(IV) complexes, , resulted in reductive halogen elimination to revert to the platinum(II) complexes almost quantitatively. Isolation of products and X-ray structure determination of the representative complexes followed all these chemical reactions. In crystal packing, the compound [PtCl2(L1c)](1c) forms dimeric units with a Pt...Pt distance of 3.699(1) A. In contrast, the crystal packing of 2b revealed that the molecules are arranged in an antiparallel fashion to form a noncovalent 1D chain to accommodate pi(aryl)-pi(pyridyl) and Pt-pi(aryl) interactions. Notably, the oxidation of [Pt(II)Cl(L2a)](2a) by I2 produced a mixed halide complex [Pt(IV)ClI2(L2a)](5), which, in turn, is reduced by ascorbate ion to produce [Pt(II)I(L2a)] with the elimination of ClI. All the platinum(II) complexes are brown, the platinum(IV) complexes, on the other hand, are green. Low-energy visible range transitions in the complexes of the extended ligand [L2]- are ascribed to ligand basedpi-pi* transitions. Cyclic voltammetric behaviour of the complexes is reported.     

Sensitive LC MS quantitative analysis of carbohydrates by Cs<Superscript>+</Superscript> attachment

The development of a sensitive assay for the quantitative analysis of carbohydrates from human plasma using LC/MS/MS is described in this paper. After sample preparation, carbohydrates were cationized by Cs(+) after their separation by normal phase liquid chromatography on an amino based column. Cesium is capable of forming a quasi-molecular ion [M + Cs](+) with neutral carbohydrate molecules in the positive ion mode of electrospray ionization mass spectrometry. The mass spectrometer was operated in multiple reaction monitoring mode, and transitions [M + 133] --> 133 were monitored (M, carbohydrate molecular weight). The new method is robust, highly sensitive, rapid, and does not require postcolumn addition or derivatization. It is useful in clinical research for measurement of carbohydrate molecules by isotope dilution assay.     

Flexible software reliability growth model with testing effort dependent learning process

A lot of importance has been attached to the testing phase of the Software Development Life Cycle (SDLC). It is during this phase it is checked whether the software product meets user requirements or not. Any discrepancies that are identified are removed. But testing needs to be monitored to increase its effectiveness. Software Reliability Growth Models (SRGMs) that specify mathematical relationships between the failure phenomenon and time have proved useful. SRGMs that include factors that affect failure process are more realistic and useful. Software fault detection and removal during the testing phase of SDLC depend on how testing resources (test cases, manpower and time) are used and also on previously identified faults. With this motivation a Non-Homogeneous Poisson Process (NHPP) based SRGM is proposed in this paper which is flexible enough to describe various software failure/reliability curves. Both testing efforts and time dependent fault detection rate (FDR) are considered for software reliability modeling. The time lag between fault identification and removal has also been depicted. The applicability of our model is shown by validating it on software failure data sets obtained from different real software development projects. The comparisons with established models in terms of goodness of fit, the Akaike Information Criterion (AIC), Mean of Squared Errors (MSE), etc. have been presented.     

Coded nanoscale self-assembly

We demonstrate coded self-assembly in nanostructures using the code seeded at the component level through computer simulations. Defects or cavities occur in all natural assembly processes including crystallization and our simulations capture this essential aspect under surface minimization constraints for self-assembly. Our bottom-up approach to nanostructures would provide a new dimension towards nanofabrication and better understanding of defects and crystallization process.      

Majorization for certain classes of analytic functions defined by fractional derivatives

Here we investigate a majorization problem involving starlike function of complex order belonging to a certain class defined by means of fractional derivatives. Relevant connections of the main results obtained in this paper with those given by earlier workers on the subject are also pointed out.     

Characterisation of different polymorphs of tris(8-hydroxyquinolinato)aluminium(III) using solid-state NMR and DFT calculations

Background  

Organic light emitting devices (OLED) are becoming important and characterisation of them, in terms of structure, charge distribution, and intermolecular interactions, is important. Tris(8-hydroxyquinolinato)-aluminium(III), known as Alq₃, an organomettalic complex has become a reference material of great importance in OLED. It is important to elucidate the structural details of Alq₃ in its various isomeric and solvated forms. Solid-state nuclear magnetic resonance (NMR) is a useful tool for this which can also complement the information obtained with X-ray diffraction studies.