DNA binding and oxidative cleavage activity of ternary (l-proline)copper(II) complexes of heterocyclic bases

Ternary copper(II) complexes Cu(l-pro)(B)(H 2O)(NO 3) (1, 2) where l-pro = l-proline, B is a N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), are synthesized, characterized, and their DNA binding and cleavage activity studied. The bpy complex (1) is structurally characterized by single-crystal X-ray crystallography. The complexes show the presence of a distorted square-pyramidal (4 + 1) CuN 3O 2 coordination geometry. Complex Cu(l-pro)(bpy)(H 2O)(NO 3) (1) crystallizes in the triclinic space group P1 with unit cell parameters: a = 7.082(3) à , b = 10.483(5) à , c = 11.581(5) à , α = 89.700(7)°, β = 83.488(8)°, γ = 84.109(8)° and V = 849.7(7) à 3. The one-electron paramagnetic complexes display a d-d band near 600 nm in water and show a cyclic voltammetric response due to Cu(II)/Cu(I) couple near 0.1 V (versus SCE) in Tris-HCl buffer-0.1 M KCl. Binding interactions of the complexes with calf thymus (CT) DNA have been investigated by emission, absorption, viscosity and DNA thermal denaturation studies. The phen complex displays significant binding propensity to the CT DNA giving an order: 2 (phen) â 1 (bpy). The bpy complex does not show any apparent binding to the DNA and hence poor cleavage efficiency. Complex 2 shows efficient oxidative cleavage of SC-DNA in the presence of 3-mercaptopropionic acid (MPA) involving hydroxyl radical species as evidenced from the control data showing inhibition of DNA cleavage in the presence of DMSO and catalase. © 2007 Elsevier Ltd. All rights reserved

FPGA based Identification of Frequency and Phase Modulated Signals by Time Domain Digital Techniques for ELINT Systems

In this paper, a decision tree algorithm based on time-domain digital technique is developed for the identification and classification of diverse radar intra-pulse modulated signals for the electronic intelligence system in real-time. This includes linear frequency modulation, non-linear frequency modulation, stepped frequency modulation and bi-phase modulation. The received signal is digitised and the instantaneous phase and high accuracy instantaneous frequency are estimated. The instantaneous amplitude is also estimated to get the start and stop of the pulse. Instantaneous parameters are estimated using a moving autocorrelation technique. The proposed algorithm is employed on the instantaneous frequency and the modulation is identified. The modulation type and modulation parameter are important for unique radar identification when similar radars are operating in a dense environment. Simulations are carried out at various SNR conditions and results are presented. The model for algorithm is developed using a system generator and implemented in FPGA. These results are compared when the proposed algorithm is used with the existing digital in-phase and quadrature-phase (DIQ) technique of instantaneous frequency and amplitude estimation

High Accuracy Parameter Estimation for Advanced Radar Identification of Electronic Intelligence System

Radar identification is one of the vital operations in an electronic intelligence system. The conventional methods based on basic parameters comparison of unique identification of a radar in a cluster of similar radars, is prone to ambiguities. To meet the current tactical requirements of unique identification of a radar, the methodology needs to be based on better feature extraction, even in low SNR conditions. The paper explores a novel technique based on moving autocorrelation for the extraction of intra-pulse and inter-pulse radar parameters. Extensive simulation and empirical studies have been carried out to establish the approach to extend accurate radar parameters in noisy and low SNR conditions. The technique is found to be promising even in field data conditions. The paper describes the methodology, simulation results, FPGA implementation using system generator and resource utilisation summary

Microstructural Characterization and Hardness Evaluation of Friction Stir Welded Composite AA6061-4.5Cu-5SiC (Wt.%)

Recent developments in advanced materials research have led to the emergence of new materials having features like low density, high strength to weight ratio, excellent mechanical properties, heat and corrosion resistance. In friction stir welding (FSW), a non-consumable rotating welding tool is used to generate the frictional heat and plastic deformation of the material in the welding zone, which is in the solid state. The advantages of FSW as compared to the fusion welding are high joint strength, less defect weld, uniform distribution of grain structure in the weld zone and low power consumption. AA6061with 4.5 % weight of copper and 5 % weight of SiC composite material has been prepared to conduct experiment and carry out characterization, evaluation of the mechanical properties. Micro-structural characterization of the weld zone is carried out by scanning electron microscope (SEM). Evaluation of hardness was also carried out across the weld zone. A successful method for FSW of AA6061-4.5(wt.%) Cu-5(wt.%) SiC has been developed.Defence Science Journal, 2013, 63(4), pp.429-434, DOI:http://dx.doi.org/10.14429/dsj.63.486

New ternary copper(II) complexes of l-alanine and heterocyclic bases: DNA binding and oxidative DNA cleavage activity

Four new ternary copper(II) complexes of α-amino acid having polypyridyl bases of general formulation [Cu(l-ala)(B)(H2O)](X) (1–4), where l-ala is l-alanine, B is an N,N-donor heterocyclic base, viz. 2,2′-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2) and 5,6-phenanthroline dione (dione, 3), dipyrido[3,2:2′,3′-f]quinoxaline (dpq, 4), and X = View the MathML source/View the MathML source are synthesized, characterized by various spectroscopic and X-ray crystallographic methods. The complexes show a distorted square-pyramidal (4 + 1) CuN3O2 coordination geometry. The one-electron paramagnetic complexes (1–4) display a low energy d–d band near 600 nm in aqueous medium and show a quasi-reversible cyclic voltammetric response due to one-electron Cu(II)/Cu(I) reduction near −100 mV (versus SCE) in DMF–0.1 M TBAP. Binding interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by UV–Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and DNA melting studies. All the complexes barring the complexes 1 and 3 are avid binder to the CT-DNA in the DNA minor groove giving an order: 4 > 2 ⋙ 1, 3. The complexes 2 and 4 show appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA) as a reducing agent. Hydroxyl radical was investigated to be the DNA cleavage active species. Control experiments in the presence of distamycin-A show primarily minor groove-binding propensity for the complexes 2 and 4 to the DNA

Microstructural Characterization and Hardness Evaluation of Friction Stir Welded Composite AA6061-4.5Cu-5SiC (Wt.%)

Recent developments in advanced materials research have led to the emergence of new materials having features like low density, high strength to weight ratio, excellent mechanical properties, heat and corrosion resistance. In friction stir welding (FSW), a non-consumable rotating welding tool is used to generate the frictional heat and plastic deformation of the material in the welding zone, which is in the solid state. The advantages of FSW as compared to the fusion welding are high joint strength, less defect weld, uniform distribution of grain structure in the weld zone and low power consumption. AA6061with 4.5 % weight of copper and 5 % weight of SiC composite material has been prepared to conduct experiment and carry out characterization, evaluation of the mechanical properties. Micro-structural characterization of the weld zone is carried out by scanning electron microscope (SEM). Evaluation of hardness was also carried out across the weld zone. A successful method for FSW of AA6061-4.5(wt.%) Cu-5(wt.%) SiC has been developed.Defence Science Journal, 2013, 63(4), pp.429-434, DOI:http://dx.doi.org/10.14429/dsj.63.486

Thermal relaxation in charge ordered Pr0.63_{0.63} Ca0.37_{0.37} MnO3_3 in presence of a magnetic field

We report observation of substantial thermal relaxation in single crystal of charge ordered system Pr$_{0.63}$Ca$_{0.37}$MnO$_3$ in an applied magnetic field of H = 8T. The relaxation is observed when the temperature is scanned in presence of a magnetic field in the temperature interval $T_{MH}<T<T_{CO}$ where $T_{CO}$ is the charge ordering temperature and $T_{MH}$ is charge melting temperature in a field. In this temperature range the system has coexisting charged ordered insulator (COI) and ferromagnetic metallic (FMM) phases. No such relaxation is observed in the COI state in H = 0T or in the FMM phase at $T < T_{MH}$ in presence of a magnetic field. We conclude that the thermal relaxation is due to two coexisting phases with nearly same free energies but separated by a potential barrier. This barrier makes the transformation from one phase to the other time-dependent in the scale of the specific heat experiment and gives rise to the thermal relaxation.Comment: 4 pages LaTEX, 3 eps figure

X-ray and ion emission studies from subnanosecond laser-irradiated SiO2 aerogel foam targets

In this experiment, a comparative study of ion and X-ray emission from both a SiO2 aerogel foam and a quartz target is performed. The experiment is performed using Nd:glass laser system operated at laser energy up to 15 J with a pulse duration of 500 ps with focusable intensity of 1013–1014 W/cm2 on target. X-ray fluxes in different spectral ranges (soft and hard) are measured by using X-ray diodes covered with Al filters of thickness 5 µm (0.9–1.56 keV) and 20 µm (3.4–16 keV). A 2.5 times enhancement in soft X-ray flux (0.9–1.56 keV) and a decrease of 1.8 times in hard X rays (3.4–16 keV) for 50 mg/cc SiO2 aerogel foam is observed compared with the solid quartz. A decrease in the flux of the K-shell line emission spectrum of soft X rays is noticed in the case of the foam targets. The high-resolution K-shell spectra (He-like) of Si ions in both the cases are analyzed for the determination of plasma parameters by comparing with FLYCHK simulations. The estimated plasma temperature and density are T c = 180 eV, n e = 7 × 1020 cm−3 and T c = 190 eV, n e = 4 × 1020 cm−3 for quartz and SiO2 aerogel foam, respectively. To measure the evolution of the plasma moving away from the targets, four identical ion collectors are placed at different angles (22.5, 30, 45, and 67.5°) from target normal. The angular distribution of the thermal ions are scaled as cosnθ with respect to target normal, where n = 3.8 and 4.8 for the foam and quartz, respectively. The experimental plasma volume measured from the ion collectors and shadowgraphy images are verified by a two-dimensional Eulerian radiative–hydrodynamic simulation (POLLUX code

Survey on the idle capacity of fish processing (freezing) plants in India - 2. East coast

The extent of idle capacity in the fish processing (freezing) plants in the east coast of India estimated by stratified random sampling and the factors responsible for the same are reported. The estimates of idle capacity of fish processing plants in the east coast for the years 1978 and 1979 were respectively 75.9% and 72.5% on the basis of 250 working days per annum and double shift per day. The percentage errors of estimates worked out to 6.9 for 1978 and 4.7 for 1979. The corresponding figures were worked out on the basis of 200 working days also. Substantial under-utilisation of plants in all the maritime states in the east coast accounted mainly to non-availability of raw material, high cost of production, shortage of power, scarcity of ice and potable water during peak season and frequent labour troubles