Effect of denaturation of DNA on the molecular organization of a fluorescent dye in ultra thin films

Acridine Orange (AO) forms H-dimer in solid state and in ultra thin films. However, H dimer of AO reduces its efficiency as a usefull material for fluorescence probe. In the present work detailed investigations has been done on the interaction of AO with different forms of DNA in order to check the effectiveness in controlling the dimeric sites of AO in the Layer by Layer (LbL) self assembled film. It was found that single stranded DNA (ssDNA) is most effective than the dsDNA and coil-shaped DNA in controlling the dimeric sites of AO in LbL film.     

Fibrillar Networks of Glycyrrhizic Acid for Hybrid Nanomaterials with Catalytic Features

Self‐assembly of the naturally occurring sweetening agent, glycyrrhizic acid (GA) in water is studied by small‐angle X‐ray scattering and microscopic techniques. Statistical analysis on atomic force microscopy images reveals the formation of ultralong GA fibrils with uniform thickness of 2.5 nm and right‐handed twist with a pitch of 9 nm, independently of GA concentration. Transparent nematic GA hydrogels are exploited to create functional hybrid materials. Two‐fold and three‐fold hybrids are developed by introducing graphene oxide (GO) and in situ‐synthesized gold nanoparticles (Au NPs) in the hydrogel matrix for catalysis applications. In the presence of GO, the catalytic efficiency of Au NPs in the reduction of p‐nitrophenol to p‐aminophenol is enhanced by 2.5 times. Gold microplate single crystals are further synthesized in the GA hydrogel, expanding the scope of these hybrids and demonstrating their versatility in materials design.     

Antioxidant Cardioprotection against Reperfusion Injury: Potential Therapeutic Roles of Resveratrol and Quercetin

Ischemia-reperfusion myocardial damage is a paradoxical tissue injury occurring during percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) patients. Although this damage could account for up to 50% of the final infarct size, there has been no available pharmacological treatment until now. Oxidative stress contributes to the underlying production mechanism, exerting the most marked injury during the early onset of reperfusion. So far, antioxidants have been shown to protect the AMI patients undergoing PCI to mitigate these detrimental effects; however, no clinical trials to date have shown any significant infarct size reduction. Therefore, it is worthwhile to consider multitarget antioxidant therapies targeting multifactorial AMI. Indeed, this clinical setting involves injurious effects derived from oxygen deprivation, intracellular pH changes and increased concentration of cytosolic Ca²⁺ and reactive oxygen species, among others. Thus, we will review a brief overview of the pathological cascades involved in ischemia-reperfusion injury and the potential therapeutic effects based on preclinical studies involving a combination of antioxidants, with particular reference to resveratrol and quercetin, which could contribute to cardioprotection against ischemia-reperfusion injury in myocardial tissue. We will also highlight the upcoming perspectives of these antioxidants for designing future studies.     

A shape-optimization technique for the capillary surface problem

Summary The problem of the construction of an equilibrium surface taking the surface tension into account leads to Laplace-Young equation which is a nonlinear elliptic free-boundary problem. In contrast to Orr et al. where an iterative technique is used for direct solution of the equation for problems with simple geometry, we propose here an alternative approach based on shape optimization techniques. The shape of the domain of the liquid is varied to attain the optimality condition. Using optimal control theory to derive expressions for the gradient, a numerical scheme is proposed and simple model problems are solved to validate the scheme.     

UV degradability of polysilanes for nanoresists examined by electron spectroscopies and photoluminescence

The aim of this study was to elucidate the degradation mechanisms in polysilanes, especially one-dimensional polysilylenes, with respect to the search for suitable resists for silicon industrial nanotechnologies. To this end we used the combined methods of photoelectron spectroscopies — PES (UPS and XPS) and photoluminescence — PL. Films of aryl-methyl-substituted polysilane chain, poly[methyl(phenyl)silylene] (PMPSi), prepared by casting from benzene solution, were analysed by X-ray and UV-induced photoelectron spectroscopy. Photoelectron spectra were recorded from the pristine PMPSi surface and after the UV photodegradation. Pronounced changes were found in the HeI induced photoelectron spectra indicating redistribution of filled Si 3s-like and Si 3p-like states. The photodegradation by UV radiation for two different degradation wavelengths λ = 266 and 355 nm was examined also by PL. We concentrated on the PL study in the region of the σ*-σ excitonic deexcitation after major degradations, studying the disorder and dangling bonds (DB) created by the degradation process. The results of both complementary methods are interpreted in accordance with our recent paper [1], with the degradation process explained by two competing phenomena, i.e. the energy dependent exciton transport by diffusion process and Si-Si bond scission. Presented at the X-th Symposium on Suface Physics, Prague, Czech Republic, July 11–15, 2005.     

Instrumented tensile-impact tests of bone

An instrumented pendulum-type impact tester was used to obtain tensile-impact properties for compact bone. Load-time histories throughout impact were recorded. Impact tests on 50 longitudinally oriented fresh-beef-bone samples yielded a proportional limit of 9.6±4.1 ksi (66.2±28.2 MPa), an ultimate stress of 17.6±5.3 ksi (121.3±36.5 MPa) and an energy-absorption capacity of 142±85 in. Ib/in.² (24900±14900 J/m²). A static tensile strength of 14.7±2.8 ksi (101±19 MPa) was obtained from static testing of 24 additional specimens. The tensile-impact strength was 20 percent higher than the static strength. Statistically significant correlations between elastic properties, impact strength and impact energy were found. Bone microstructure and fracture-surface topography were also examined.     

On construction and uses of balancedn-ary designs

Summary Methods of construction of balancedn-ary designs using difference sets have been studied in this paper. Some properties of balancedn-ary designs are studied. Use of balanced ternary designs has been made to construct some efficient weighing designs. Institute of Agricultural Research Statistics     

Two-body T-matrix continued off the energy shell

A generalized parametrization scheme, which treats both half-shell and off-shell scattering on equal footing, is derived for the two-particle transition operator. The appropriate theory in respect of this is developed by using a wave function approach to off-shell scattering and the computational procedure to be followed is demonstrated by means of a model calculation.     

On the nature of the phase transition in the KDP systems

Using the Landau theory of phase transitions it has been shown that for a second order phase transition Ω/k_BT_c ? 0.01. and its isomorphs 4Ω/J¹ ? 1 and for a first order transition Ω/k_BT_c ? 0.01.