Synthesis, structure, DNA binding and oxidative cleavage activity of ternary (l-leucine/isoleucine) copper(II) complexes of heterocyclic bases

Six ternary α-amino acid copper(II) complexes of the general formula Cu(AA)(B)(H 2O)(X) (1-6), where AA is l-leu = l-leucine (1-3) or l-ile = l-isoleucine (4-6), B is a N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1, 4), 1,10-phenanthroline (phen, 2, 5) and dipyrido3,2:2â²,3â²-fquinoxaline (dpq, 3, 6) and X = ClO 4 - / NO 3 - have been synthesized, characterized, and their DNA binding and cleavage activity studied. The bpy and dpq complexes of l-ile (4, 6) have been structurally characterized by X-ray crystallography. The complexes show a distorted square-pyramidal (4 + 1) CuN 3O 2 coordination geometry. The one-electron paramagnetic complexes display a d-d band near 600 nm in water and show a cyclic voltammetric response due to a Cu(II)/Cu(I) couple near -0.1 V (vs. SCE) in DMF-0.1 M TBAP. All complexes are 1:1 electrolytes. Binding interactions of the complexes with calf thymus DNA (CT-DNA) have been investigated by absorption, emission, viscosity and DNA melting studies. The phen and dpq complexes are avid binders to the calf thymus DNA, giving an order: (3, 6) (dpq) > (2, 5) (phen) â« (1, 4) (bpy). The bpy complexes do not show any apparent binding to the DNA and hence show poor DNA cleavage activity. The phen and dpq complexes (2, 3, 5, 6) show efficient oxidative cleavage of pUC19 supercoiled DNA (SC-DNA) in the presence of the reducing agent 3-mercaptopropionic acid (MPA) involving hydroxyl radical ( {radical dot}OH) species, as evidenced from the control data showing inhibition of DNA cleavage in the presence of {radical dot}OH radical quenchers, viz. DMSO, mannitol, KI and catalase. © 2008 Elsevier Ltd. All rights reserved

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

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

Investigation on Semi-active Suspension System for Multi-axle Armoured Vehicle using Co-simulation

The objective of the study is to evaluate the performance of various semi-active suspension control strategies for 8x8 multi-axle armoured vehicles in terms of comparative analysis of ride quality and mobility parameters during negotiation of typical military obstacles. Since the cost, complexity and time precludes realisation of actual system, co-simulation technique has been effectively implemented for this investigation. Co-simulation combines advanced virtual prototyping and control technology which offers a novel approach to investigate the dynamics of such complex system. The simulations for the integrated control system along with multi body model of the vehicle are carried out for the control strategies, viz. continuous sky hook control, cascade loop control and cascade loop with ride control and compared with passive suspension system. The vehicle with 8x8 configuration is run on the real world obstacle profiles, viz. step, trench, trapezoidal bump and corrugated road and the effect of control strategies on ride comfort, wheel displacement and ground reaction is presented. It is observed that cascade loop with ride control in semi-active mode offers better vehicle ride comfort while crossing the said obstacles. The improved performance parameters are achieved through stabilisation of heave, pitch and roll motions of the vehicle through outer loop and isolation of vehicle level uneven disturbances through the fuzzy logic controller employed in inner loop

Oxamido binuclear copper (II) complexes: Synthesis, crystal structure, DNA interaction and antibacterial studies

Four binuclear copper (II) complexes Cu(oxpn)Cu(B)2+ (2-5) bridged by N, Nâ²-bis3-(methylamino) propyl oxamide (oxpn), where, B is N, N-donor heterocyclic bases (viz. 2,2â²-bipyridine (bpy, 2), 1,10-phenathroline (phen, 3), dipyrido3,2-d:2â²,3â²-fquinoxaline (dpq, 4) and dipyrido3,2-a:2â²,3â²-cphenazine (dppz, 5) are synthesized, characterized by different spectroscopic and single crystal X-ray data technique. The phen (3) and dpq (4) complexes were structurally characterized by X-ray data analysis. Their DNA binding, oxidative cleavage and antibactirial activities were studied. The dpq (4) and dppz (5) complexes are avid binders to the Calf thymus DNA (CT-DNA). The phen (3), dpq (4) and dppz (5) complexes show efficient oxidative cleavage of supercoiled DNA (SC DNA) through hydroxyl radical (OH) pathway in the presence of Mercaptopropionic acid (MPA). © 2013 Elsevier Ltd. All rights reserved

Synthesis, Crystal Structure, Antioxidant, Antimicrobial, and Mutagenic Activities and DNA Interaction Studies of Ni(II) Schiff Base 4-Methoxy-3-Benzyloxybenzaldehyde Thiosemicarbazide Complexes

Three new Ni(II) square planar complexes of 4-methoxy-3-benzyloxybenzaldehyde thiosemicarbazide(4m3BTSC) having polypyridyl bases of general formulation [ML2] (1) and [MLB] (2, 3), where L = 4m3BTSC and B is N,N-donor heterocyclic bases, namely, 1,10-phenanthroline (phen, 2), 2,2′-bipyridine (bpy, 3), are synthesized and characterized. The free radical scavenging assay results showed that complex 1 possesses significant activity when compared to complexes 2 and 3. The biological studies showed that the ligand and its complexes exhibited significant and different biological activities and also the prepared compounds are nonmutagenic. They may be potential commercial antioxidants because of their nonmutagenic and nontoxic nature. The DNA interaction of the new complexes is evaluated by absorption, emission, and melting temperature methods, and the results suggested that the binding affinity of the complexes increases with the presence of planar ligand in the molecule. The nickel (II) complexes with planar phenanthroline bases show moderate DNA binding and cleavage ability

Oxidative DNA cleavage, cytotoxicity and antimicrobial studies of l-ornithine copper (II) complexes

New ternary copper (II) complexes, Cu(l-orn)(B)(Cl)(Cl·2H 2O) (1-2) where l-orn is l-ornithine, B is an N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1) and 1,10-phenanthroline (phen, 2), were synthesized and characterized by various spectroscopic techniques. Complex 2 is characterized by the X-ray single crystallographic method. The complex shows a distorted square-pyramidal (4 + 1) CuN 3OCl coordination sphere. 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. Complex 2 shows appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA). The complexes were subjected to in vitro cytotoxicity studies against carcinomic human alveolar basal epithelial cells (A-549) and human epithelial (HEp-2) cells. The IC 50 values of 1 and 2 are less than that of cisplatin against HEp-2 cell lines. MIC values for 1 against the bacterial strains Streptococcus mutans and Pseudomonas aeruginosa are 0.5 mM. © 2012 Elsevier Ltd. All rights reserved

Assessment of P-Delta Effect on High Rise Buildings

P-delta effect is secondary effect on structure .it is also known as ‘Geometric nonlinearity effect’. As number of stories increases, P-delta effect becomes more important. If the change in bending moments and displacements is more than 10%, P-delta effect should be considered in design. In this study the P-delta effect on high rise building is studied. Linear static analysis (without P-delta effect) on high rise building having different number of stories is carried out. For the analysis G+14, G+19, G+24, (i.e 15, 20, and 25storey) R.C.C. framed building are modeled. Earthquake load is applied on model of structure as per IS-18939(2002) for zone III in E-Tab software. Load combination for analysis is set as per IS-456(2000).All analysis is carried out in software ETAB. Bending moment, story displacement with and without p-delta effect is calculated and compared for all the models. Then by trial and error method suitable cross-section are provided for unsafe building to bring within acceptable limit by increasing stiffness of a building. The result shows that it is essential to consider the P-delta effect for 25storey building. So buildings having height more than or equal to 75m, should be designed considering P-delta effect. Also we can say that up to 25storey building, it is not necessary to consider P-delta effect in design and primary or first order analysis is sufficient for design. By increasing stiffness of building by providing suitable cross section or by increasing stiffness building can bring within acceptable limit.[7] DOI: 10.17762/ijritcc2321-8169.150515

Itinerant electron metamagnetism in LaCo9_9Si4_4

The strongly exchange enhanced Pauli paramagnet LaCo$_9$Si$_4$ is found to exhibit an itinerant metamagnetic phase transition with indications for metamagnetic quantum criticality. Our investigation comprises magnetic, specific heat, and NMR measurements as well as ab-initio electronic structure calculations. The critical field is about 3.5 T for $H||c$ and 6 T for $H\bot c$, which is the lowest value ever found for rare earth intermetallic compounds. In the ferromagnetic state there appears a moment of about 0.2 $\mu_B$/Co at the $16k$ Co-sites, but sigificantly smaller moments at the 4d and $16l$ Co-sites.Comment: 11 pages, 5 figures, PRB Rapid Communication, in prin