Optical multi-sensor for simultaneous measurement of absorbance,turbidity, and fluorescence of a liquid

We have built a novel optical multi-sensor apparatus (MSA) for the measurement of light absorption, scattering and fluorescence either separately or simultaneous from a liquid. From the measured data it is possible to calculate different optical properties of liquid samples, such as absorbance and turbidity. The MSA is a portable device which is an advantage considering different field applications. The MSA was tested in laboratory conditions using well-known reference liquids. Data obtained with the MSA were compared with data obtained with a commercial spectrophotometer, fluorometer and a nephelometer, respectively. Relatively good correlations between the data of MSA and the three commercial devices were found. It is proposed that MSA is a potential device for monitoring changes of process liquids and liquid products in industry.     

Clunie theorems for difference and q-difference polynomials

The main purpose of this paper is to prove difference and q-differencecounterparts of the Clunie and Mohon’ko lemmas from theNevanlinna theory of differential polynomials. We also giveapplications to the value distribution theory of meromorphicsolutions of some complex difference equations.     

Interplay of matrix element, self-energy and geometric effects in various spectroscopies of the cuprates

We discuss a comprehensive scheme for modeling various highly resolved spectroscopies of the cuprates where effects of matrix element, crystal structure, strong electron correlations, and superconductivity are included realistically in material-specific detail. A number of illustrative examples drawn from our recent work are presented. Specific issues in the cuprate physics considered are: (i) Origin of high-energy kink or the waterfall effect; (ii) Dichroic effects in angle-resolved photoemission spectrum; (iii) Asymmetry of the scanning tunneling spectrum between the processes of electron extraction and injection; (iv) Persistence of ‘Mott’ like high-energy features with doping in optical spectra; (v) Magnetic excitations in electron and hole doped cuprates.     

Synthesis,spectroscopy, magnetism and X-ray structure of μ-(bipyrimidine)-bis[aqua(bipyrimidine)(saccharinato)copper(II)] bis(saccharinate) tetrahydrate

The compound [Cu₂(bipym)₃(sac)₂(H₂O)₂](sac)₂(H₂O)₄ (bipym = 2,2-bipyrimidine and sac = saccharin) crystallizes in the space group P-1, with a = 10.710(3), b = 10.725(3), c = 13.637(5) Å, a = 70.07(3), = 80.31(2), g = 82.87(3)° and Z = 2. The geometry in the centrosymmetric dinuclear complex around each Cu^II ion is a distorted octahedron, in which the equatorial plane is formed by a nitrogen atom of a bis-didentate bridging bipym ligand, two nitrogen atoms of a didentate bipym ligand, and the nitrogen atom of a coordinating sac ligand. The axial positions in the octahedron are occupied by a second nitrogen of the bis-didentate bridging bipym ligand and a water molecule. The lattice contains two saccharinate anions and four water molecules held together in a hydrogen-bonded network. The i.r vibrations of the bipym ligand are found as a quasi-symmetric doublet at 1558 and 1580 cm^–1, while the most important i.r vibrations of the sac ligand are observed at 1629 and 1644 cm^–1 (carbonyl vibrations) and at 1285 and 1159 cm^–1 (sulfonyl vibrations). The magnetic exchange interactions between the Cu ions is very weak and is ferromagnetic (J < 0.1 cm^–1).     

Crystal structure and spectroscopy of bis-[bis(2-benzimidazolyl)propane]copper(II) bis(triflate)monohydrate, a copper complex with a geometry intermediate between tetrahedral and square planar

The structure of a mononuclear copper(II) compound with the ligand bis(2-benzimidazolyl)propane (abbreviated as tbz) is reported. The compound [Cu(tbz)₂](CF₃SO₃)₂(H₂O) crystallizes in the triclinic space group P , with a = 12.363(6), b = 13.218(9), c = 15.365(8) Å, = 82.74(5), = 68.04(4), = 65.30(5), and Z = 2. The Cu(II) atom has a geometry intermediate between tetrahedral and square planar, consisting of four nitrogen atoms of two tbz ligands. The Cu—N—Cu angles are about 135°, while the dihedral angle between them amounts to 62° (0° for square planar and 90° for a tetrahedron). Ligand field bands are observed at 10.2 × 10³, 13.8 × 10³, and 20.3 × 10³ cm^–1, while the most characteristic infrared vibrations of the triflate anion are observed at 1273, 1260, 1238, 1221, 1171, and 1157 cm^–1.     

Growth of solutions of second order linear differential equations

We consider the differential equation , where and are entire functions. Provided and as outside a set of finite logarithmic measure, we prove that all nonconstant solutions of this equation are of infinite order.

     

Structure and DNA cleavage properties of two copper(II) complexes of the pyridine-pyrazole-containing ligands mbpzbpy and Hmpzbpya

The DNA-cleavage properties of the two copper(II) complexes, [Cu(mbpzbpy)Br(2)](H(2)O)(2.5) (1) and [Cu(mpzbpya)Cl](CH(3)OH) (2), obtained from the ligands 6,6'-bis(3,5-dimethyl-N-pyrazolmethyl)-2,2'-bipyridine) (mbpzbpy) and 6'-(3,5-dimethyl-N-pyrazolmethyl)-2,2'-bipyridine-6-carboxylic acid) (Hmpzbpya), respectively, are reported. Upon coordination to Cu(II) chloride in methanol, one arm of the ligand mbpzbpy is hydrolyzed to form mpzbpya. Under the same experimental conditions, the reaction of mbpzbpy with CuBr(2) does not lead to ligand hydrolysis. The ligand mpzbpya is coordinated to a copper(ii) ion generating a CuN(3)OCl chromophore, resulting in a distorted square-pyramidal environment, whereas with the N(4) mbpzbpy ligand, the Cu(II) ion is four-coordinated in a distorted square planar geometry. Both complexes promote the oxidative DNA cleavage of phiX174 phage DNA in the absence of reductant. The oxidative nature of the DNA cleavage reaction has been confirmed by religation and cell-transformation experiments. Studies using standard radical scavengers suggest the involvement of hydroxyl radicals in the oxidative cleavage of DNA. Although both compounds do convert form I (supercoiled) DNA to form II (nicked, relaxed form), only complex 1 is able to produce small amounts of form III (linearized DNA). This observation may be explained either by the attack of the copper(ii) complexes to only one single strand of DNA, or by a single cleavage event. Statistical analysis of relative DNA quantities present after the treatment with both copper(ii) complexes supports a random mode of DNA cleavage.