Zn(II)-cyclam based chromogenic sensors for recognition of ATP in aqueous solution under physiological conditions and their application as viable staining agents for microorganism

Two chromogenic complexes, L.Zn (where L is (E)-4-((4-(1,4,8,11-tetraazacyclotetradecan-1-ylsulfonyl)phenyl)diazenyl)-N,N-dimethylaniline) and its [2]pseudorotaxane form (α-CD.L.Zn), were found to bind preferentially to adenosine triphosphate (ATP), among all other common anions and biologically important phosphate (AMP, ADP, pyrophosphate, and phosphate) ions in aqueous HEPES buffer medium of pH 7.2. Studies with live cell cultures of prokaryotic microbes revealed that binding of these two reagents to intercellular ATP, produced in situ, could be used in delineating the gram-positive and the gram-negative bacteria. More importantly, these dyes were found to be nontoxic to living microbes (eukaryotes and prokaryotes) and could be used for studying the cell growth dynamics. Binding to these two viable staining agents to intercellular ATP was also confirmed by spectroscopic studies on cell growth in the presence of different respiratory inhibitors that influence the intercellular ATP generation.     

Application of backscattering spectrometry for composition and thickness determination of zirconium oxide layers on autoclaved zircaloy

Summary The determination of atomic composition and thickness of zirconium oxide layers on zirconium based alloys is of practical interest in nuclear industry. This paper describes the application of backscattering spectrometry for the non-destructive determination of composition and thickness of zirconium oxide layers on autoclaved zircaloy coupons. The spectrometry used here is the Rutherford backscattering spectrometry (RBS) with 2.5 MeV α-particles, 3.05 MeV ¹⁶O(α,α)¹⁶O resonance scattering and ¹⁶O(p,p)¹⁶O elastic scattering with 2.5 MeV proton beam. Proton backscattering is found to be the most suitable technique for the overall compositional analysis of the layers whereas 3.05 MeV ¹⁶O(α,α)¹⁶O resonance scattering, for depth profiling of oxygen. The former technique is simple and provides rapid measurements. The lower stopping cross sections of protons and enhanced scattering cross section for oxygen over a wide range of proton energy enable the analysis of oxide layers of larger thicknesses. The thicknesses of these layers determined by backscattering are in good agreement with cross-sectional micrographs taken by scanning electron microscope (SEM).     

Depth profiling Cr in surface layers by 52Cr(p,γ)53Mn nuclear resonance reaction analysis

A method for depth profiling chromium in the surface and near surface regions of materials using the resonance at 1,005 keV in ⁵²Cr(p,γ)⁵³Mn nuclear reaction is presented. The detection sensitivity, depth resolution and probing depth of the resonance in Si are determined to be about 3 at.%, 25 nm and 2.5 µm respectively from the excitation function of the reaction constructed in 0.90–1.2 MeV proton energy region by measuring 378 keV prompt γ-rays from ⁵³Mn nuclei. The reaction is interference free. These features make the approach attractive for profiling chromium in mid as well as high Z matrices.     

Comparison of sodium zirconium phosphate and calcium zirconium phosphate structures for the retention of fluoride

Fluoride anion interaction has been explored for the first time to investigate how the structure of sodium zirconium phosphate (NZP) and calcium zirconium phosphate (CZP) can be altered in its presence. Different compositions were made by adding NaF and CaF₂ in CZP and NZP matrices respectively. Fluoride interaction differs with NZP and CZP structure as suggested by F-NMR data. The addition of fluoride to the NZP or CZP structure enables to stabilize the structure at a low temperature of 600–700 °C under microwave conditions.     

An Algorithm for the 0-1 Equality Knapsack Problem

The 0-1 knapsack problem is a linear integer-programming problem with a single constraint and binary variables. The knapsack problem with an inequality constraint has been widely studied, and several efficient algorithms have been published. We consider the equality-constraint knapsack problem, which has received relatively little attention. We describe a branch-and-bound algorithm for this problem, and present computational experience with up to 10,000 variables. An important feature of this algorithm is a least-lower-bound discipline for candidate problem selection.     

A New Generation of Anticancer Drugs: Mesoporous Materials Modified with Titanocene Complexes

The next generation : The grafting of titanocene complexes on the surfaces of MCM‐41 and SBA‐15 led to a new generation of anticancer drugs, which are very active against human cancer cells.

     

Protein‐Functionalized Synthetic Antiferromagnetic Nanoparticles for Biomolecule Detection and Magnetic Manipulation

Direct protein functionalization provides synthetic antiferromagnetic nanoparticles with high chemical specificity and multifunctionality. These nanoparticle–protein conjugates function as improved magnetic labels for biological detection experiments, and exhibit tunable responses to a small external magnetic field gradient, thus allowing the observation of distinctive single nanoparticle motion.

     

A study of the influence of chemical environment on the Li (i = 1–3) subshell X-ray intensity ratios and the L3 absorption-edge energy for some compounds of 66Dy using synchrotron radiation

In the present work, the X-ray intensity ratios, I_Lk/I_Lα (k = l, β, γ_1,5, γ₂,₃, γ₄), have been measured for different compounds of ₆₆Dy, namely, Dy₂O₃, Dy₂(CO₃)₃, Dy₂(SO₄)₃.8H₂O, DyI₂, and the ₆₆Dy metallic foil by tuning the incident photon energies across its L_i (i = 1–3) absorption-edge energies covering the region 7.8–10 keV in order to investigate the influence of chemical effects on these intensity ratios in the presence of the many-body effects, which become significant at photon energies in proximity to the L_i absorption-edge energies. The present measured intensity ratios I_Lk/I_Lα have been compared with two sets of values calculated using the nonrelativistic Hartree–Fock–Slater model-based L_i (i = 1–3) subshell photoionization cross sections, the Dirac–Fock model-based X-ray emission rates, and two sets of the fluorescence and Coster–Kronig yields. The L₃ absorption-edge energy of ₆₆Dy in its different compounds and metallic foil has been deduced from the XANES spectra recorded in the present work. The L₃ absorption-edge energy shifts obtained from these absorption-edge energies are found to increase linearly with the partial charge on the metal atom (₆₆Dy).     

Singularity of orbits in classical Lie algebras

We determine the maximum k such that the k-fold sum of some nontrivial, adjoint orbit in the Lie algebra of a classical, compact Lie group has measure zero. The orbits of minimal dimension are seen to be the extreme examples. We show that for this choice of k there is a central, continuous measure on the group such that ^k is singular to L ¹. For Lie groups other than type B _n or C ₃ this result is sharp.