Mode spectra of natural disturbances in a circular jet and the effect of acoustic forcing

A modal spectrum technique was used to study coherent instability modes (both axisymmetric and azimuthal) triggered by naturally occurring disturbances in a circular jet. This technique was applied to a high Reynolds number (400,000) jet for both untripped (transitional) and tripped (turbulent) nozzle exit boundary layers, with both cases having a core turbulence level of 0.15%. The region up to the end of the potential core was dominated by the axisymmetric mode, with the azimuthal modes dominating further downstream. The growth of the azimuthal modes was observed closer to the nozzle exit for the jet with a transitional boundary layer. Whether for locally parallel flow or slowly diverging flow, even at low levels of acoustic forcing, the inviscid linear theory is seen to be inadequate for predicting the amplitude of the forced mode. In contrast, the energy integral approach reasonably predicts the evolution of the forced mode.     

Synthesis,DNA binding,and antimicrobial studies of novel metal complexes containing a pyrazolone derivative Schiff base

A novel series of Co(II), Ni(II), Cu(II), Zn(II), and VO(IV) complexes has been synthesized from the Schiff base derived from 4-[(3,4-dimethoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one and 1,2-diaminobenzene. Structural features were determined by analytical and spectral techniques. Binding of synthesized complexes with calf thymus DNA (CT DNA) was studied by spectroscopic methods and viscosity measurements. Experimental results indicate that the complexes are able to form adducts with DNA and to distort the double helix by changing the base stacking. Lower DNA affinity of the VO(IV) complex is caused by the change of coordination geometry by the vanadyl ion resulting in a somewhat unfavorable configuration for the DNA binding. Oxidative DNA cleavage activities of the complexes were studied with supercoiled (SC) pUC19 DNA using gel electrophoresis; the mechanism studies revealed that the hydroxyl radical is likely to be the reactive species responsible for the cleavage of pUC19 DNA by the synthesized complexes. The in vitro antimicrobial screening effects of the investigated compounds were monitored by the disc diffusion method. The synthesized Schiff base complexes exhibit higher antimicrobial activity than the respective free Schiff base.     

Preparation of electrodeless discharge lamps for emission studies of uranium isotopes at trace level

A simplified method for preparation of electrodeless discharge lamp for uranium isotopes with specific concerns for ²³²U is described. Micro-gram quantities of solid uranium oxides and aqueous solution of uranium nitrate have been used as a starting material for in situ synthesis of uranium tetraiodide. High temperature iodination reaction is carried out in the presence of inert gas neon. By careful design, the preparation time and surface area of quartz reaction tubes have been reduced considerably. The latter decreases the level of contamination which has a direct bearing on the operational lifetime of the lamps. Incorporation of steps to purify the product from an unwanted material improved the stability of the lamps. The procedure provides a safe and convenient way of handling ²³²U in particular but can be extended in general to any actinides having radioactivity similar to that of freshly separated ²³²U. Characteristic emission of uranium isotopes have been recorded by Fourier Transform Spectrometer to show the satisfactory operation of the lamps as well as their usage for studying emission spectra of the specific isotope.     

Anti-ulcer activity of Smithia conferta in various animal

Smithia conferta Sm. (Leguminasae), is a commonly used plant in Indian traditional medicine. In the current study anti-ulcer activity of its petroleum ether, alcohol and aqueous extracts of leaves were investigated using different animal models. All extracts were also subjected to phytochemical analysis and their toxic potential. Petroleum ether extract was found to contain steroids; alcohol extract revealed the presence of isoflavonoids, alkaloids and carbohydrates; while aqueous extract was found to contain amino acids, carbohydrates and flavonoids. S. conferta aqueous and alcoholic extracts were found to be non-toxic up to 5000 mg/kg dose level while petroleum ether extract was safe only up to a dose of 2000 mg/kg after single dose administration of the extracts.During confirmation of the claimed anti-ulcer activity, treatment with aqueous and alcoholic extracts showed significant reduction in ulcer index, free acidity as well as total acidity in pylorus ligated rats. However, petroleum ether extract showed relatively less profound reduction in all these indices. The anti-ulcer activity observed in aqueous extract treatment group was nearly equivalent to the standard group.     

Preparation and characterization of hydroxypropyl-β-cyclodextrin inclusion complex of eugenol: differential pulse voltammetry and (1)H-NMR

The objective of present investigation was to improve the solubility of Eugenol by preparing the inclusion complex of Eugenol with hydroxypropyl-β-cyclodextrin (Hp-β-CD) and characterize the prepared complex by using NMR and differential pulse voltammetry (DPV). Phase solubility curve was plotted using Hp-β-CD in ranging from 0-40 mM of Hp-β-CD and found to be linear. Therefore, inclusion complex was prepared in equimolar ratio of Eugenol and Hp-β-CD by lyophilization method. Fourier transform infrared spectroscopy (FT-IR), (1)H-NMR and DPV were performed for Eugenol, Hp-β-CD and prepared inclusion complex of Eugenol. 2D (two dimensional) NMR was also performed for prepared inclusion complex. The proton of phenol moiety of Eugenol experienced a pronounced chemical shift variation in (1)H-NMR. The positive sign of the variation for proton in (1)H-NMR indicated that the proton was located near to an oxygen atom in the Hp-β-CD cavity and its magnitude showed a strong interaction between -OH proton of Eugenol and Hp-β-CD. 2D NMR confirms the interaction between phenolic group and hydrogen atoms of Hp-β-CD. A well defined anodic peak current corresponding to oxidation of Eugenol in non-encapsulated and Hp-β-CD-Eugenol inclusion complex in phosphate buffer (pH 6.8) was obtained at about 0.35 V and 0.40 V, respectively. The positive shift in oxidation potential indicated the formation of complex via hydrophobic interactions. The oxidant power of Eugenol was retained in complex form as indicated by DPV results. Thus, its oxidation dependent pharmacological property such as antimicrobial activity is not affected after complexation with Hp-β-CD. Thus, (1)H-NMR, 2D-NMR and DPV techniques can be used as valuable tools to determine the mechanism of complexation and state of electrochemical active drug in inclusion complex.     

On the directed Full Degree Spanning Tree problem

We study the parameterized complexity of a directed analog of the Full Degree Spanning Tree problem where, given a digraph $D$ and a nonnegative integer $k$, the goal is to construct a spanning out-tree $T$ of $D$ such that at least $k$ vertices in $T$ have the same out-degree as in $D$. We show that this problem is W[1]-hard even on the class of directed acyclic graphs. In the dual version, called Reduced Degree Spanning Tree, one is required to construct a spanning out-tree $T$ such that at most $k$ vertices in $T$ have out-degrees that are different from that in $D$. We show that this problem is fixed-parameter tractable and that it admits a problem kernel with at most $8k$ vertices on strongly connected digraphs and $O\left(k^2\right)$ vertices on general digraphs. We also give an algorithm for this problem on general digraphs with running time $O(5.942^k?n^{O\left(1\right)})$, where $n$ is the number of vertices in the input digraph.     

Parametrizing the lepton mixing matrix in terms of charged lepton corrections

We consider a parametrization of the lepton mixing matrix in which the deviations from maximal atmospheric mixing and vanishing reactor mixing are obtained in terms of small corrections from the charged lepton sector. Relatively large deviations for the reactor mixing angle from zero as indicated by T2K experiment can be obtained in this parametrization. We are able to further reduce the number of complex phases, thus, simplifying the analysis. In addition, we have obtained the sides of unitarity triangles and the vacuum oscillation probabilities in this parametrization. The Jarlskog rephasing invariant measure of CP violation at the leading order has a single phase difference which can be identified as Dirac-type CP violating phase in this parametrization.     

In situ, on-resin synthesis of 8-Br/NH2 adeninyl peptide nucleic acid (PNA) oligomers and complementation studies with DNA

A new, novel and efficient in situ synthesis of 8-aminoadeninyl PNA oligomers from corresponding 8-bromoadeninyl PNA oligomers is reported. The study of hybridisation properties of (8-Br/8-NH₂) PNA oligomers with cDNA reveals substitution-site dependent stabilization of derived triplexes and duplexes.