We have studied the chemical interaction of heavy metal ions such as Hg(II), Hg(I), Pb(II), and Cd(II) of various concentrations with naked and protected silver nanoparticles (Ag@citrate and Ag@MSA, respectively, where MSA is mercaptosuccinic acid). The particles were of 30 and 8 nm diameter, respectively. We observed that the metal ions interact with both the core of the nanoparticles and the ...

Metallic copper alloys have recently attracted attention as a new antimicrobial weapon for areas where surface hygiene is paramount. Currently it is not understood on a molecular level how metallic copper kills microbes, but previous studies have demonstrated that a wide variety of bacteria, including Escherichia coli, Staphylococcus aureus, and Clostridium difficile, are inactivated within min...

Studies of metal nanocluster (M-NCs)-based sensors for specific analyte detection have achieved significant progress in recent decades. Ultra-small-size (<2 nm) M-NCs consist of several to a few hundred metal atoms and exhibit extraordinary physical and chemical properties. Similar to organic molecules, M-NCs display absorption and emission properties via electronic transitions between energy l...

The toxicity of metallic nanoparticles (MNPs) has been fully ascertained, but the mechanisms underlying their cytotoxicity remain still largely unclear. Here we demonstrate that the cytotoxicity of MNPs is strictly reliant on the pathway of cellular internalization. In particular, if otherwise toxic gold, silver, and iron oxide NPs are forced through the cell membrane bypassing any form of acti...

X-ray absorptioń spectroscopy, today widely used as a tool for structural investigations, is described. Theoretically it is shown that above an absorption edge the absorption coefficient is well approximated by a sum of terms, each one describing a particular path followed by the photoelectron outgoing from the atom. Such geometrical feature allows to use X-ray absorption spectroscopy for struc...

In this paper we report on our theoretical studies of various aspects of the correlated stopping power of two pointlike ions (a dicluster) moving in close but variable vicinity of each other in some metallic target materials, the latter being modeled by a degenerate electron gas with appropriate densities. Within the linear-response theory we have made a comprehensive investigation of correlate...

In the last few years, we have been developing a Monte Carlo simulation method to cope with systems of many electrons and ions in the Born-Oppenheimer approximation: the coupled electron-ion Monte Carlo method (CEIMC). Electronic properties in CEIMC are computed by quantum Monte Carlo rather than by density functional theory (DFT) based techniques. CEIMC can, in principle, overcome some of the ...

The quaternary thio-phosphate, Cs(0.49)NbPS(6), caesium hexa-thio-niobiophosphate(V), has been synthesized by the reactive halide flux method. The title compound is isotypic with Rb(0.46)TaPS(6) and is made up of a bicapped trigonal-biprismatic [Nb(2)S(12)] unit and a tetra-hedral [PS(4)] group. The [Nb(2)S(12)] units linked by the [PS(4)] tetra-hedra form infinite chains, yielding a three-dime...

A protein conformation transition from random coil and/or helical conformation to beta-sheet is known to be central to the process used by silk-spinning spiders and insects to convert concentrated protein solutions to tough insoluble threads. Several factors including pH, metallic ions, shear force, and/or elongational flow can initiate this transition in both spiders and silkworms. Here, we re...

The discovery was made that an orthophosphate-repressible alkaline phosphatase exists in Neurospora crassa. Variable phosphate levels in the culture medium caused the enzyme to vary in the order of loo-fold in its range of spechic activities. The properties of this ZO-fold purified enzyme clearly differentiated it from the alkaline phosphomonoesterase of N. crassa, a Pi-repressible alkaline pho...