Isonitrile ligand properties as studied by He I/He II photoelectron spectroscopy

A new series of isonitrile-substituted cobalt tricarbonyl nitrosyl (Co(CO)₂(NO)CNR, R = Me, Et, ⁿPr, ⁱPr, ⁿBu, ⁿPe, CH₂Si(CH₃)₃) has been synthesized, and their He I ultraviolet photoelectron spectra are reported. The assignment of the bands in the low energy part of the spectra was performed with the aid of DFT calculations. The first vertical ionization energies of the complexes were found to be 7.73 (CNMe), 7.58 (CNEt), 7.59 (CNⁿPr), 7.70 (CNⁿBu), 7.67 (CNⁿPe), 7.77 (CNⁱPr), and 7.54 ± 0.03 eV (CNCH₂Si(CH₃)₃). In the case of ⁿPr- and CH₂Si(CH₃)₃- substitutions, He II photoelectron spectra were also recorded. The relative importance of electronic and steric effects of the isonitrile ligands, as a function of the size of group –R, is discussed.     

The incidence class and the hierarchy of orbits

R. Rimányi defined the incidence class of two singularities η and ζ as [η]|ζ, the restriction of the Thom polynomial of η to ζ. He conjectured that (under mild conditions) [η]|ζ ≠ 0 ⇔ ζ ⊂ . Generalizing this notion we define the incidence class of two orbits η and ζ of a representation. We give a sufficient condition (positivity) for ζ to have the property that [η]|ζ ≠ 0 ⇔ ζ ⊂ for any other orbit η. We show that for many interesting cases, e.g. the quiver representations of Dynkin type positivity holds for all orbits. In other words in these cases the incidence classes completely determine the hierarchy of the orbits. We also study the case of singularities where positivity doesn’t hold for all orbits.      

Validation of a tentative microsatellite marker for the dopamine D4 receptor gene by capillary gel electrophoresis

Two to four-basepair-short tandem repeats (i.e. microsatellites) are broadly utilized as genetic markers for mapping disease loci in whole genome search analyses. Based on their close vicinity on chromosome 11, the D11S1984 microsatellite was anticipated as a tentative marker for the dopamine D4 receptor gene. A capillary gel electrophoresis based genotype analysis method and an in-house made computational tool was developed for the analysis of the D11S1984 microsatellite marker to examine a healthy Hungarian population of n=106. The data obtained did not suggest significant linkage between the D11S1984 marker and the DRD4 gene.     

The singularity of positive linear functionals

Our purpose is to show that the various concepts of singularity of representable positive functionals on ^?-algebras coincide, moreover to present a new characterization of singularity by means of Choquet theory of the state space. In the context of singularity, the paper includes an equivalent condition for a representable positive functional to be pure.     

Viehwegʼs hyperbolicity conjecture is true over compact bases

We prove Viehweg?s hyperbolicity conjecture over compact bases and over bases with non-uniruled compactification. The most general case of the conjecture states that the base space of a maximal variation family of smooth projective manifolds with semi-ample canonical sheaf is of log-general type.     

Highly selective palladium-catalyzed aminocarbonylation and cross-coupling reactions on a cavitand scaffold

Palladium-catalyzed aminocarbonylation and cross-coupling reactions (Suzuki-, Sonogashira-, Stille-coupling) served as highly efficient synthetic tools for the synthesis of novel, functionalized deepened cavitands. Unexpectedly high chemoselectivities towards tetrafunctionalized cavitands have been observed for all of these reactions even using coupling partners much below the stoichiometric amount. No significant formation of either the mono-, di- or trifunctionalized products was observed.     

Self-association-driven transition of the β-peptidic H12 helix to the H18 helix

Various patterns of foldameric oligomers formed by trans-ABHC ((1S,2S,3S,5S)-2-amino-6,6-dimethylbicyclo[3.3.1]heptane-3-carboxylic acid) and β(3)-hSer residues were studied. NMR, ECD and molecular modelling demonstrated that octameric and nonameric sequences with multiple i-i+3 ABHC pair repulsions attain the β-H18 helix in CD(3)OH. As a close relative of the α-helix, this helix type is stabilized by i-i+4 backbone H-bond interactions. The formation of the β-H18 helix was found to be solvent- and concentration-dependent. Upon dilution, the β-H18 → β-H12 helix transition was revealed by concentration-dependent ECD, DOSY-NMR and TEM measurements.     

Enzymic Methylation of Ascorbigen and Demethylation of Its N-Methyl Derivative by Pseudomonas savastanoi pv. phaseolicola Bacteria

Biotransformation of ascorbigen and N-methylascorbigen as a model compound pair was studied in the presence of Pseudomonas savastanoi pv. phaseolicola bacterium cells. These compounds were separated from a methanolic mixture by using an overpressured layer chromatographic method. After saturation of the developed chromatoplates with the bacterial cell suspension, the composition of the chromatographic spots was analyzed by means of high performance liquid chromatography. Pattern recognition by independent multicategory analysis was used to compare of the retention behavior of the standard and putative ascorbigen and methylascorbigen, and to manage the analytical data. Results showed that ascorbigen was partially methylated and N-methylascorbigen was partially demethylated by the bacteria. Our new results confirm the former assumption that formaldehyde is formed by demethylation of the N-methyl group of methylascorbigen.

     

Aminosilane-based functionalization of two-photon polymerized 3D SU-8 microstructures

There is an increasing interest in functionalized complex 3D microstructures with sub-micrometer features for micro- and nanotechnology applications in biology. Depending primarily on the material of the structures various methods exist to create functional layers of simple chemical groups, biological macromolecules or metal nanoparticles. Here an effective coating method is demonstrated and evaluated on SU-8 based 3D microstructures made by two-photon polymerization. Protein streptavidin and gold nanoparticles (NP) were bound to the microstructures utilizing acid treatment-mediated silane chemistry. The protein surface density, quantified with single molecule fluorescence microscopy revealed that the protein forms a third of a monolayer on the two-photon polymerized structures. The surface coverage of the gold NPs on the microstructures was simply controlled with a single parameter. The possible degrading effect of the acid treatment on the sub-micrometer features of the TPP microstructures was analyzed. Our results show that the silane chemistry-based method, used earlier for the functionalization of large-area surfaces can effectively be adapted to coat two-photon polymerized SU-8 microstructures with sub-micrometer features.