Synthesis of lariat organochalcogenoethers based on azacalix[3]arenes for the potentiometric detection of [UO2] ions

The syntheses of organochalcogen-supported azacalix[3]arenes are described in a one-pot manner in satisfactory yields. A remarkably selective potentiometric response was accomplished for uranyl ions over a variety of other metal ions, including alkali (Na⁺, K⁺), alkaline-earth (Mg²⁺, Ca²⁺, Ba²⁺), transition and heavy metal ions (Co²⁺, Ni²⁺, Cu²⁺, Ag⁺, Fe³⁺, Zn²⁺, Cd²⁺ and Pb²⁺) using an ion-selective electrode based on compound 3 incorporated into a polymeric (PVC) membrane.     

A Study on Uptake and Localization of Merocyanine 540 (MC540) in Murine Myeloid Leukemia Cells by Confocal Laser Scanning Microscopy (CLSM)

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｍｅｒｏｃｙａｎｉｎｅ540(ＭＣ540),ａｎａｍｐｈｉｐａｔｈｉｃｄｙｅｔｈａｔｐｒｅｆｅｒｅｎｔｉａｌｌｙｂｉｎｄｓｔｏｌｅｕｋｅｍｉａｃｅｌｌ,ｅｎｖｅｌｏｐｅｄｖｉｒｕｓａｎｄｃｅｒｔａｉｎｖｉｒｕｓｉｎｆｅｃｔｅｄｃｅｌｌｓ[1～3].ＭＣ540ｍｅｄｉａｔｅｓｔｈｅｐｈｏｔｏｄｙｎａｍｉｃｋｉｌｌｉｎｇｏｆｌｅｕｋｅｍｉａｃｅｌｌｓ,ｗｈｅｒｅａｓｎｏｒｍａｌｂｏｎｅｍａｒｒｏｗａｎｄｂｌｏｏｄｃｅｌｌｓａｒｅｌａｒｇｅｌｙｓｐａｒｅｄ.Ｉｔｈａｓｂｅｅｎｕｓｅｄｐｒｅ…     

Distribution of merocyanine 540 in phospholipid membranes

The interaction of the fluorescent photosensitizer merocyanine 540 (MC-540) with model phospholipid membranes was studied. Two different-colored species (monomers and dimers) of MC-540 were registered in phospholipid liposomes. Variations in both phospholipid composition (DMPC, DPPC, POPC, egg PC) and temperature (15–60°C) resulted in changes in the MC-540 monomerdimer distribution. The values of the monomer-dimer equilibrium constant of MC-540 in egg PC (K=14.8 M), in POPC (K=26.7 M), and in DMPC (K=271.0 M) were determined at the temperature of 23±2°C. Suppression of MC-540 association with phospholipid bilayers was provoked by the addition of albumin to a liposome suspension. Albumin was observed to compete very successfully with lecithins containing saturated fatty acid chains (DPPC, DMPC), while only a weak competition of albumin with unsaturated lecithins (POPC, egg PC) for binding MC-540 molecules was registered.     

Bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) Complexes Containing 2-Arylimidazo-phenanthroline: Syntheses, Characterization and Third-order Nonlinear Optical Properties

ＩｎｔｒｏｄｕｃｔｉｏｎＯｒｇａｎｏｍｅｔａｌｌｉｃａｎｄｃｏｏｒｄｉｎａｔｉｏｎｃｏｍｐｌｅｘｅｓｈａｖｅｒｅ ｃｅｎｔｌｙｅｍｅｒｇｅｄａｓｐｏｔｅｎｔｉａｌｂｕｉｌｄｉｎｇｂｌｏｃｋｓｆｏｒｎｏｎｌｉｎｅａｒｏｐｔｉｃａｌ (ＮＬＯ )ｍａｔｅｒｉａｌｓ .1 6Ｃｏｍｐａｒｅｄｗｉｔｈｏｒｇａｎｉｃｍｏｌｅｃｕｌｅｓ ,ｍｅｔａｌｃｏｍｐｌｅｘｅｓｃａｎｈａｖｅａｌａｒｇｅｒｖａｒｉｅｔｙｏｆｓｔｒｕｃｔｕｒｅｓａｎｄａｍｕｃｈｇｒｅａｔｅｒｄｉｖｅｒｓｉｔｙｏｆｔｕｎａｂｌｅｅｌｅｃ ｔｒｏｎｉｃ…     

Investigation of thermal properties of ruthenium(III) Β-diketonate precursors for preparation of RuO2 films by CVD

By means of a tensimetric flow method and a static method with a silica-membrane zero gauge, the dependence of vapour pressure on temperature was obtained for tris(2,4-pentanedionato)ruthenium(III), Ru(aa)₃, and tris(1,1,1-trifluoropentane-2,4-dionato)ruthenium(III), Ru(tfa)₃. The thermodynamic characteristics of vaporization and sublimation of these complexes were determined. The processes of thermal decomposition of the vapour of the compounds in vacuum, hydrogen and oxygen were investigated by using mass spectrometry in the temperature range 170–550540nlu238061257/xxlarge8225.gif" alt="Dagger" align="MIDDLE" BORDER="0">C for Ru(aa)₃ and 150–620540nlu238061257/xxlarge8225.gif" alt="Dagger" align="MIDDLE" BORDER="0">C for Ru(tfa)₃. The threshold temperatures of the stability of the vapour of the complexes and the rate constants of the thermolysis processes were determined. The main gaseous products of the thermal decomposition and the dependences of their composition on the presence of hydrogen and oxygen were established.     

Ab initio study of electronic spectra of merocyanine 540 and its photoproducts

Molecular structures of three derivatives of merocyanine 540 (MC 540) were studied using the density functional method in conjunction with the 6‐31G*, 6‐31G**, and 6‐311G** basis sets. The excited states were calculated using the configuration interaction method involving singly excited configurations (CIS). The predicted transition energies and oscillator strength agree well with the experimental UV adsorption spectra of the studied systems. The existence of two stable conformers of merocyanine explain the experimentally observed dependence of the UV spectra upon the change of concentration of added salts. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002     

Photophysical studies of Merocyanine 540 dye in aqueous micellar dispersions of different surfactants and in different solvents

The fluorescence spectra of Merocyanine 540 (MC 540), an anionic dye have been studied in aqueous solution of different nonionic surfactants. The results show the enhancement and red shift of fluorescence bands, indicating electron transfer from the surfactants to the excited dye. This is also supported by the photovoltage generation by the dye-surfactant systems in a photoelectrochemical cell. Possible mechanisms of the excited state interaction and photovoltage generation have been suggested. From the thermodynamic, spectrophotometric and photogalvanic results, it can be concluded that the electron donating abilities of the nonionic surfactants towards MC 540 are in the order: Tween 80 approximately Tween 60>Tween 40>Tween 20>Triton X-100. The spectral studies (both absorption and fluorescence) of Merocyanine 540 have been carried out in solvents of varying polarities as well as in an aqueous micellar dispersions of nonionic surfactants. The Stokes shifts of the fluorescence from the absorption have been found to increase with increasing polarity of the solvents. An attempt has been made to ascertain the polarity of the microenvironment of Merocyanine 540 in the nonionic surfactant media from the photophysical characteristics of the dye in different solvents of known polarities.     

Fluorescence quenching of fluorescein by Merocyanine 540 in liposomes

The fluorescence quenching of fluorescein (FL) by merociyanine 540 (MC540) was examined in L-egg lecithin phosphatidycholine (PC) liposomes using spectroscopic methods. The type of quenching mechanism (dynamic or static) was evaluated using the Stern-Volmer plots. Findings were also supported by the temperature studies and florescence decay measurements. The Stern-Volmer equation was utilized to calculate bimolecular quenching constants (K_q). Furthermore, the bimolecular quenching constant of the quencher in the liposomes (K_SV), partition coefficient (K_p), binding constant (K), and corresponding thermodynamic parameters ΔH, ΔS, and ΔG were calculated. The quenching property was also used in determining quantitatively (K_p) the partition coefficient of Merociyanini 540 in PC liposome.The obtained data indicated that static quenching occurred in the system and the K_SV values decreased with increasing lipid concentration. In addition, thermodynamic analysis suggested that van der Waals interactions and hydrogen bonding were the main acting forces between fluorescein and merociyanine 540 molecules in the medium.     

Satisfiability of mixed Horn formulas

In this paper the class of mixed Horn formulas is introduced that contain a Horn part and a 2-CNF (conjunctive normal form) (also called quadratic) part. We show that SAT remains NP-complete for such instances and also that any CNF formula can be encoded in terms of a mixed Horn formula in polynomial time. Further, we provide an exact deterministic algorithm showing that SAT for mixed Horn formulas containing n variables is solvable in time O(2^0.5284n). A strong argument showing that it is hard to improve a time bound of O(2^n/2) for mixed Horn formulas is provided. We also obtain a fixed-parameter tractability classification for SAT restricted to mixed Horn formulas C of at most k variables in its positive 2-CNF part providing the bound O(∥C∥2^0.5284k). We further show that the NP-hard optimization problem minimum weight SAT for mixed Horn formulas can be solved in time O(2^0.5284n) if non-negative weights are assigned to the variables. Motivating examples for mixed Horn formulas are level graph formulas [B. Randerath, E. Speckenmeyer, E. Boros, P. Hammer, A. Kogan, K. Makino, B. Simeone, O. Cepek, A satisfiability formulation of problems on level graphs, ENDM 9 (2001)] and graph colorability formulas.     

采用氧合血红蛋白吸收带的漫反射光谱比率R（540）/R（575）检测浅表性膀胱癌

采用氧合血红蛋白在540和575 nm吸收带的漫反射光谱比率(R540/R575)对人浅表性膀胱癌进行了鉴别诊断,实验采用带积分球附件的分光光度计获取组织的漫反射光谱。结果表明:正常膀胱的粘膜/粘膜下层组织的漫反射光谱比率(R540/R575)在组织离体后2 h的平均值为111%,3 h的平均值为107%,4 h的平均值为104%,5 h的平均值为102%,而浅表性的膀胱癌的粘膜/粘膜下层组织的漫反射光谱比率(R540/R575)在组织离体后2 h的平均值为98.4%,3 h的平均值为95.5%,4 h的平均值为93.1%,5 h的平均值为91.6%,正常膀胱与浅表性膀胱癌的粘膜/粘膜下层组织在组织离体后2,3,4和5 h的漫反射光谱比率(R540/R575)均有显著性的差异(p<0.05),分别为12.6%,11.5%,10.9%和10.4%。这结论为快速、低成本、非入侵的浅表性膀胱癌的光活检提供了一种新的方法。