Mechanical and electrical properties of nanostructured ‘plastic metals’

Deformable, supraspherical (SS) aggregates of metal nanoparticles (NPs) connected by long-chain dithiol ligands self-assemble into nanostructured materials of macroscopic dimensions. These materials are both malleable/moldable at room temperature as well as electrically conductive. Upon gentle heating, they harden into polycrystalline metals. The paper discusses qualitative models that rationalize the mechanical and electrical properties of these unusual ‘plastic metals’.     

Electro-optic polymer frequency shifter activated by input optical pulses

We demonstrate electro-optic frequency shifting of 1.55-microm optical pulses by as much as 86 GHz in a polymer traveling-wave phase modulator. The optical pulses were modulated with the linear region of quasi-sinusoidal microwave pulses. In the implemented configuration the electro-optic frequency shifter does not require synchronization with the source of the optical pulses, making it transparent to the optical-pulse repetition rate and increasing its utility. Electro-optic frequency conversion has a number of advantages compared with other methods of all-optical frequency conversion, including no need for a second optical source, high conversion efficiency, and simple control of the output frequency.     

Hypochlorous acid-induced oxidative damage of human red blood cells: effects of tert-butyl hydroperoxide and nitrite on the HOCl reaction with erythrocytes

Hypochlorous acid, one of the most powerful biological oxidants, is believed to be important in the pathogenesis of some diseases. The purpose of this study was to further characterise the membrane and intracellular events which resulted in HOCl-induced oxidative impairments and haemolysis of human erythrocytes and interaction of different oxidative agents, which accumulated during respiratory burst, in the process of RBS oxidation. The sequence of cellular events after red blood cell exposure to HOCl: cell morphological transformations, oxidation of cellular constituents, enzyme modifications, and haemolysis have been evaluated. It was shown that HOCl-treated cells underwent colloid-osmotic haemolysis, preceded by rapid morphological transformations and membrane structural transitions. The activation energy of the process of haemolysis (after removal of the excess of oxidative agent) was estimated to be 146+/-22 kJ/mol at temperatures above the break point of Arrhenius plot (31-32 degrees C). This value corresponds to the activation energy of the process of protein denaturation. Modification of erythrocytes by HOCl inhibited membrane acetylcholinesterase (uncompetitive type of inhibition), depleted intracellular glutathione, activated intracellular glutathione peroxidase, but did not induce membrane lipid peroxidation. The presence of other oxidants, nitrite or tert-butyl hydroperoxide (t-BHP), promoted the oxidative damage induced by HOCl and led to new oxidative reactions.     

Matrix representations of truncated Toeplitz operators

In this paper we describe matrix representations of truncated Toeplitz operators on the model space _KB$K_B$, where B is an infinite Blaschke product satisfying some additional conditions. Our results are extensions of that obtained by Cima, Ross and Wogen in 2008.