Sturmian Ground States in Classical Lattice–Gas Models

Journal of Statistical Physics - We construct for the first time examples of non-frustrated, two-body, infinite-range, one-dimensional classical lattice–gas models without periodic...     

On estimating of the number of constituents of a finite mixture of continuous distributions

Summary Suppose thatH is a mixture of distributions for a given familyF A necessary and sufficient condition is obtained under whichH is, in fact, a finite mixture. An estimator of the number of distributions constituting the mixture is proposed assuming that the mixture is finite and its asymptotic properties are investigated.     

Fabrication of blazed gratings by area-coded effective medium structures

Area-coded effective medium structures (ACES) are a recently presented novel type of diffractive structure. Because of their higher stability compared to 2D binary blazed gratings, they have the potential of a broader use in micro-optics applications. The first fabrication with electron-beam lithography validate the theoretical model of blazed ACES. The measured diffraction efficiencies are in very good agreement with the values obtained from rigorous electromagnetic analysis.     

Comparison of infrared-excited up-converting phosphors and europium nanoparticles as labels in a two-site immunoassay

Research in the field of immunoassays and labels used in the detection has been recently focused on particulate reporters, which possess very high specific activity that excludes the label as a sensitivity limiting factor. However, the large size and shape of the particulate labels may produce additional problems to immunoassay performance. The aim of this work was to study with two identical non-competitive two-site immunoassays whether up-converting phosphor (UCP) particles are comparable in performance with europium(III) chelate-dyed nanoparticles as particulate labels. In addition we strived to verify the common assumption of the photostability of up-converting phosphor particles supporting their potential applicability in imaging. Detection limits in two-site immunoassay for free prostate-specific antigen (free-PSA) were 0.53 ng L⁻¹ and 1.3 ng L⁻¹ using two different up-converting phosphors and 0.16 ng L⁻¹ using europium(III) nanoparticle. Large size distribution and non-specific binding of up-converting phosphor particles caused assay variation in low analyte concentrations and limited the analytical detection limit. The non-specific binding was the major factor limiting the analytical sensitivity of the immunoassay. The results suggests the need for nanoscaled and uniformely sized UCP-particles to increace the sensitivity and applicability of up-converting phosphor particles. Anti-Stokes photoluminescence of up-converting phosphor particles did not photobleach when measured repeatedly, on the contrary, the time-resolved fluorescence of europium nanoparticles photobleached relatively rapidly.     

Synthesis,antimicrobial activity and high cell viability of copper derivatives of 2-thiouracil,purine-6-thione and 2,4,6-trimercaptotriazine

Reactions of copper(II) acetate with 2-thiouracil (tucH₂) and triphenyl phosphine (1:1:1 or 1:1:2 molar ratios) in methanol-acetonitrile/chloroform mixture yielded a light brown N,S-bridged dinuclear Cu^I complex, [Cu(PPh₃)₂(µ-N,S-tucH)Cu(PPh₃)₂Cl] 1, incorporating uninegative 2-thiouracilate. X-ray crystallography has shown that the crystals of complex 1 comprise a two component twin system and belong to the space group Ia. The major component 1a is about 77% and the minor component 1b is about 23%. One Cu is four-coordinate tetrahedral with center {CuP₂SCl} and the other Cu is three-coordinate distorted trigonal planar with {CuP₂N} center. Crystal data: 1, formula, C₇₆H₆₃ClCu₂N₂OP₄S; space group: Ia; monoclinic, a, 22.2638(9); b, 11.8050(4); c, 27.4455(10) Å; β, 113.358(5); R, 4.80%;173(2) K. The antimicrobial activities of dinuclear 1 as well as that of the previously reported 2-thiouracil, 2,4,6-trimercaptotriazine (tmtH₃) and purine-6-thione (purSH₂) complexes, [CuCl(κ¹-S-tucH₂)(PPh₃)₂] 2, [Cu₂Br₂(μ-S-tucH₂)₂(PPh₃)₂] 3, [Cu(tmtH₂)(PPh₃)₂] 4, [Cu₃Br₂(k¹-N,k¹-S,µ-S-tmtH₂)(PPh₃)₆] 5 and [Cu(k¹-N,k¹-S-purSH)(PPh₃)₂] 6, have been screened against gram negative, Escherichia coli (MTCC 119) and Shigella flexneri (MTCC 1457), gram positive, Enterococcus faecalis (MTCC 439) and Staphylococcus aureus (MTCC 740) microorganism. High percentage of cell viability (96–97%) is observed in some cases.     

Constructing bounded remainder sets and cut-and-project sets which are bounded distance to lattices

For any irrational cut-and-project setup, we demonstrate a natural infinite family of windows which gives rise to separated nets that are each bounded distance to a lattice. Our proof provides a new construction, using a sufficient condition of Rauzy, of an infinite family of non-trivial bounded remainder sets for any totally irrational toral rotation in any dimension.     

Feasibility of density functional methods to predict dielectric properties of polymers

Feasibility of density functional theory (DFT) to predict dielectric properties such as polarizability of saturated polymers is investigated. Small saturated molecules, methane and propane, which is a monomer of polypropylene chain, are used in testing the methods. Results for polarizabilities based on several density functionals together with different basis sets are compared and contrasted with each other, with results by Hartree-Fock and second-order Moller-Plesset perturbation theory, as well as experimental data. The generalized gradient approximation PW91 method together with the 6-311++G(**) basis set is found to be the most suitable method, in terms of sufficient accuracy and computational efficiency, to calculate polarizabilities for large oligomers of polypropylene. The dielectric constant is then determined using the calculated polarizabilities and the Clausius-Mossotti equation. The molecular DFT methods at the PW916-311++G(**) level together with the Clausius-Mossotti equation give dielectric constants for saturated polymers such as polypropylene in good accordance with the experimental values.     

Ring‐opening metathesis polymerization of a modified linseed oil with varying levels of crosslinking

A commercial norbornyl‐functionalized linseed oil, blended with a bicyclic norbornene‐based crosslinking agent (at loadings ranging from 0 to 50 wt %) undergoes ring‐opening metathesis polymerization with the 1st generation Grubbs' catalyst to form a biorenewable polymer network. Comonomers are characterized, the thermal and mechanical properties of the cured systems are investigated by dynamic mechanical analysis, and thermal decomposition is evaluated by thermogravimetric analysis. The resin is shown to consist of a modified linseed oil and small oligomers of cyclopentadiene. Broad tan δ peaks suggest inhomogeneous phase morphologies, which result in complex crosslinking behaviors. The thermal stability of the polymers increases with increasing crosslinker content. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6851–6860, 2008