Differentiation of Vitis vinifera varieties by MALDI-MS analysis of the grape seed proteins

Until now the study of pathogenic related proteins in grape juice and wine, performed by ESI-MS, LC/ESI-MS, and MALDI/MS, has been proposed for differentiation of varieties. In fact, chitinases and thaumatin-like proteins persist through the vinification process and cause hazes and sediments in bottled wines. An additional instrument, potentially suitable for the grape varieties differentiation, has been developed by MALDI/MS for the grape seed protein analysis. The hydrosoluble protein profiles of seeds extract from three different Vitis vinifera grape (red and white) varieties were analyzed and compared. In order to evaluate the environmental conditions and harvest effects, the seed protein profiles of one grape variety from different locations and harvests were studied.     

Assessment of water-soluble pi-extended squaraines as one- and two-photon singlet oxygen photosensitizers: design, synthesis, and characterization

Singlet oxygen sensitization by organic molecules is a topic of major interest in the development of both efficient photodynamic therapy (PDT) and aerobic oxidations under complete green chemistry conditions. We report on the design, synthesis, biology, and complete spectroscopic characterization (vis-NIR linear and two-photon absorption spectroscopy, singlet oxygen generation efficiencies for both one- and two-photon excitation, electrochemistry, intrinsic dark toxicity, cellular uptake, and subcellular localization) of three classes of innovative singlet oxygen sensitizers pertaining to the family of symmetric squaraine derivatives originating from pi-excessive heterocycles. The main advantage of pi-extended squaraine photosensitizers over the large number of other known photosensitizers is their exceedingly strong two-photon absorption enabling, together with sizable singlet oxygen sensitization capabilities, for their use at the clinical application relevant wavelength of 806 nm. We finally show encouraging results about the dark toxicity and cellular uptake capabilities of water-soluble squaraine photosensitizers, opening the way for clinical small animal PDT trials.     

Heteroleptic copper(I) complexes coupled with methano[60]fullerene: synthesis, electrochemistry, and photophysics

Heteroleptic copper(I) complexes CuPOP-F and CuFc-F have been prepared from a fullerene-substituted phenanthroline ligand and bis[2-(diphenylphosphino)phenyl] ether (POP) and 1,1'-bis(diphenylphosphino)ferrocene (dppFc), respectively. Electrochemical studies indicate that some ground-state electronic interaction between the fullerene subunit and the metal-complexed moiety are present in both CuPOP-F and CuFc-F. Their photophysical properties have been investigated by steady state and time-resolved UV-vis-NIR luminescence spectroscopy and nanosecond laser flash photolysis in a CH2Cl2 solution and compared to those of the corresponding model copper(I) complexes CuPOP and CuFc and of the fullerene model compound F. Selective excitation of the methanofullerene moiety in CuPOP-F results in regular deactivation of the lowest singlet and triplet states, indicating no intercomponent interactions. Conversely, excitation of the copper(I)-complexed unit (405 nm, 40% selectivity) shows that the strongly luminescent triplet metal-to-ligand charge-transfer ((3)MLCT) excited state located at 2.40 eV is quenched by the carbon sphere with a rate constant of 1.6 x 10(8) s(-1). Details on the mechanism of photodynamic processes in CuPOP-F via transient absorption are hampered by the rather unfavorable partition of light excitation between the two chromophores. By determination of the yield of formation of the lowest fullerene triplet level through sensitized singlet oxygen luminescence in the NIR region, it is shown that the final sink of photoinduced processes is always the fullerene triplet. This can be populated via a two-step charge-separation charge-recombination process and a less favored (3)MLCT --> (3)C60 triplet-triplet energy-transfer pathway. In CuFc-F, both of the photoexcited copper(I)-complexed and fullerene moieties are quenched by the presence of the ferrocene unit, most likely via ultrafast energy transfer.     

Generating the patterns of variation with GeoGebra: the case of polynomial approximations

In this paper, we report a teaching experiment regarding the theory of polynomial approximations at the university mathematics teaching in Sweden. The experiment was designed by applying Variation theory and by using the free dynamic mathematics software GeoGebra. The aim of this study was to investigate if the technology-assisted teaching of Taylor polynomials compared with traditional way of work at the university level can support the teaching and learning of mathematical concepts and ideas. An engineering student group (n = 19) was taught Taylor polynomials with the assistance of GeoGebra while a control group (n = 18) was taught in a traditional way. The data were gathered by video recording of the lectures, by doing a post-test concerning Taylor polynomials in both groups and by giving one question regarding Taylor polynomials at the final exam for the course in Real Analysis in one variable. In the analysis of the lectures, we found Variation theory combined with GeoGebra to be a potentially powerful tool for revealing some critical aspects of Taylor Polynomials. Furthermore, the research results indicated that applying Variation theory, when planning the technology-assisted teaching, supported and enriched students’ learning opportunities in the study group compared with the control group.     

On the Maximum Weight of a Sparse Connected Graph of Given Order and Size

The weight of an edge of a graph is defined to be the sum of degrees of vertices incident to the edge. The weight of a graph G is the minimum of weights of edges of G. Jendrol’ and Schiermeyer (Combinatorica 21:351–359, 2001) determined the maximum weight of a graph having n vertices and m edges, thus solving a problem posed in 1990 by Erd?s. The present paper is concerned with a modification of the mentioned problem, in which involved graphs are connected and of size \(m\le \left( {\begin{array}{c}n\\ 2\end{array}}\right) -\left( {\begin{array}{c}\lceil n/2\rceil \\ 2\end{array}}\right) \).     

A practical synthesis of 2,4(5)-diarylimidazoles from simple building blocks

A simple and efficient approach to selectively obtain 2,4(5)-diarylimidazoles suppressing formation of 2-aroyl-4(5)-arylimidazoles is described. The yield of each of the two products strongly depends on the reaction conditions employed. This reaction provides a simple method to prepare small libraries of biologically active compounds by parallel synthesis.     

Strukturuntersuchungen an Usoviten: Ba2CaMIIV2F14 (MIII = Mn,Fe), Ba2CaMnFe2F14 und Ba2CaCuM2IIIF14 (MIII = Mn,Fe, Ga)

Structural Studies with Usovites: Ba₂CaM^IIV₂F₁₄ (M^III = Mn, Fe), Ba₂CaMnFe₂F₁₄ and Ba₂CaCuM₂^IIIF₁₄ (M^III = Mn, Fe, Ga). Single crystals of six compounds Ba₂CaM^IIM₂^IIIF₁₄ were prepared to refine their usovite type structure (space group C2/c, Z = 4) using X‐ray diffractometer data. The cell parameters of the phases studied with M^IIM₂^III= MnV₂, FeV₂, CuMn₂, MnFe₂, CuFe₂ und CuGa₂ are within the range 1374≤a/pm≤1384, 534≤b/pm≤542, 1474≤c/pm≤1510, 91, 3≤ß/°≤93, 2. The atoms Ca and M^II are incompletely ordered on the 8‐ and 6‐coordinated positions, 4e and 4b, respectively. In the case of Ba₂CaFeV₂F₁₄ and Ba₂CaCuGa₂F₁₄ there is reciprocal substitution (x≈0, 1): (Ca_1‐xM_x^II) (4e) and (M_1‐x^IICa_x) (4b). In the case of the other usovites Ca‐enriched phases Ba₂Ca(M_1‐y^IICa_y)M₂^IIIF₁₄ occured (up to y≈0, 35), exhibiting partial substitution at the octahedral position (4b) only, showing a corresponding increase in M^II‐F distances. The distortion of [M^IIF₆] and [M^IIIF₆] octahedra within the structure is considerably enhanced on replacement by Cu^II and Mn^III. The results of powder magnetic susceptibility measurements of Ba₂CaMnV₂F₁₄ and Ba₂CaFeV₂F₁₄ (T_N≈7K) are reported.