Diagnostics of an inductively coupled plasma in oxygen

Spatial time-integrated and space-time resolved profiles of excited atoms of oxygen were measured by optical emission spectroscopy for inductively coupled plasma (ICP) in oxygen. The discharge was sustained by a single turn coil supplied by 13.56 MHz RF generator delivering 100 and 200 W of power. The spatial emission profiles give the anatomy of the discharge required in order to understand the basic kinetics of ICP. Two types of nonuniformities are observed, azimuthal anisotropy and radial nonuniformity, both caused by spatially dependent energy supply to the electrons. Our experimental results show that oxygen is much more affected by azimuthal anisotropy and radial nonuniformity than argon. It is due to a different role of metastable atoms in kinetics of excitation, whereby stepwise excitation in oxygen is less probable than in argon. Optical emission data are supplemented by Langmuir probe measurements of electron densities and plasma potentials. Electrons gain energy from the time varying fields close to the coil, and the energy is not redistributed along the radius before it is dissipated in excitation, thus the observations are not consistent with the nonlocal theory predictions for the range of pressures, geometry, and power covered in this paper     

TOF-SIMS surface analysis of L-Tryptophan self assembled monolayer

This paper dealt with the preparation and characterization of self — assembled monolayersSAM-s of 1-hexadecanethiole and mercapto acetic acid on the silver nanostructure and subsequently the immobilization with amino acid L-Tryptophane. In order to achieve it, we used the electrodeposition of silver onto nanostructured surface of paraffin impregnated graphite electrode (PIGE). Subsequently, we assembled SAM by choosing the 1-hexadecanethiole and mercaptoacetic acid. These two kinds of SAM underwent the functionalization by L-Tryptophan. The observations of silver on PIGE surfaces were performed by scanning electron microscope (SEM). For surface analysis of the SAM functionalized by L-tryphophan, the TOF-SIMS technique was chosen. Finally, the fragmented ions of the immobilized-L-Tryptophan SAM were determined on the basis of suggested residues and three-dimensional structure. The residues show that the ability of L-Tryptophan to build homogeneous structure is better by mercaptoacetic acid SAM structure than by 1-hexadecanethiol. It was observed that L-Tryptophan built compact surface, which, due its chemical properties, can represent very interesting side regarding biocompatibility, homochirality and robustness in the area of life science.      

Phase diagram of K(x)Fe(2-y)Se(2-z)S(z) and the suppression of its superconducting state by an Fe2-Se/S tetrahedron distortion

We report structurally tuned superconductivity in a K(x)Fe(2-y)Se(2-z)S(z) (0 ≤ z ≤ 2) phase diagram. Superconducting T(c) is suppressed as S is incorporated into the lattice, eventually vanishing at 80% of S. The magnetic and conductivity properties can be related to stoichiometry on a poorly occupied Fe1 site and the local environment of a nearly fully occupied Fe2 site. The decreasing T(c) coincides with the increasing Fe1 occupancy and the overall increase in Fe stoichiometry from z = 0 to z = 2. Our results indicate that the irregularity of the Fe2-Se/S tetrahedron is an important controlling parameter that can be used to tune the ground state in the new superconductor family.     

Combined scenarios of chemical and ecological quality under water scarcity in Mediterranean rivers

Water resources are directly and indirectly affected by anthropogenic activities (e.g., changes in land use) and natural factors (e.g., climate change), that is, global change. The Mediterranean basin is one of the most vulnerable regions of the world to global change, and one of the “hot spots” for forthcoming problems of water availability. The present review provides an overview about the relationship between chemical quality (especially concerning organic microcontaminants) and water scarcity, particularly in the Mediterranean area. We include an overview of environmental contaminants and analytical methodologies and consider the fate and the behavior of organic contaminants, and the effects of pollutants on ecosystems.     

Synthesis of Oligonucleotides containing the cis-Interstrand Crosslink Produced by Mitomycins in their Reaction with DNA

Mitomycin C (MC) an antitumor drug and decarbamoylmitomycin C (DMC), a derivative of MC lacking the carbamoyl moiety, are DNA alkylating agents which can form DNA interstrand crosslinks (ICLs) between deoxyguanosine residues located on opposing DNA strands. MC forms primarily deoxyguanosine adducts with a 1“-R stereochemistry at the guanine-mitosene bond (1”-α, trans) whereas DMC forms mainly adducts with a 1“-S stereochemistry (1”-β, cis). The crosslinking reaction is diastereospecific: trans-crosslinks are formed exclusively at CpG sequences, while cis-crosslinks are formed only at GpC sequences. Until now, oligonucleotides containing 1“-β-deoxyguanosine adducts or ICL at a specific site could not be synthesized, thus limiting the investigation of the role played by the stereochemical configuration at C1′′ in the toxicity of these compounds. Here, a novel biomimetic synthesis to access these substrates is presented. Structural proof of the adducted oligonucleotides and ICL were provided by enzymatic digestion to nucleosides, high resolution mass spectral analysis, CD spectroscopy and UV melting temperature studies. Finally, a virtual model of the 25-mer 1”-β ICL synthesized was created to explore the conformational space and structural features of the crosslinked duplex.     

A new dispatching rule based genetic algorithm for the multi-objective job shop problem

Hyper-heuristics or “methodologies to choose heuristics” are becoming increasingly popular given their suitability to solve hard real world combinatorial optimisation problems. Their distinguishing feature is that they operate in the space of heuristics or heuristic components rather than in the solution space. In Dispatching Rule Based Genetic Algorithms (DRGA) solutions are represented as sequences of dispatching rules which are called one at a time and used to sequence a number of operations onto machines. The number of operations that each dispatching rule in the sequence handles is a parameter to which DRGA is notoriously sensitive. This paper proposes a new hybrid DRGA which searches simultaneously for the best sequence of dispatching rules and the number of operations to be handled by each dispatching rule. The investigated DRGA uses the selection mechanism of NSGA-II when handling multi-objective problems.