Konrad Zdanowski

The Doping Effect of Fluorinated Aromatic Solvents on the Rate of Ruthenium‐Catalysed Olefin Metathesis

A study concerning the effect of using a fluorinated aromatic solvent as the medium for olefin metathesis reactions catalysed by ruthenium complexes bearing N-heterocyclic carbene ligands is presented. The use of fluorinated aromatic hydrocarbons (FAH) as solvents for olefin metathesis reactions catalysed by standard commercially available ruthenium pre-catalysts allows substantially higher yields of the desired products to be obtained, especially in the case of demanding polyfunctional molecules, including natural and biologically active compounds. Interactions between the FAH and the second-generation ruthenium catalysts, which apparently improve the efficiency of the olefin metathesis transformation, have been studied by X-ray structure analysis and computations, as well as by carrying out a number of metathesis experiments. The optimisation of reaction conditions by using an FAH can be regarded as a complementary approach for the design of new improved ruthenium catalysts. Fluorinated aromatic solvents are an attractive alternative medium for promoting challenging olefin metathesis reactions.

Fluorescence and NMR studies of intramolecular stacking of mRNA cap-analogues.

Intramolecular stacking of a series of new synthesized dinucleotide mRNA cap analogues has been investigated in aqueous buffers by means of fluorescence and 1H-NMR at various pH and temperatures, and compared with that for 7-methylguanosine(5)ppp(5)guanosine (m7GpppG), as well as its hypermethylated derivative m(3)2,2,7GpppG. Thermodynamic parameters for intramolecular self-association stabilized by stacking were established by temperature-dependent fluorescence quenching, taking into account collisional deactivation of the excited states. Relative orientations of the stacked bases in the cap analogues were determined with the aid of a program GEOSHIFT (Stolarski et al., Biochim. Biophys. Acta (1996) 1293, 97), based on ring-current anisotropy. 1D-soft-TOCSY experiments were applied to extract the exact values of vicinal coupling constants, and hence to resolve solution conformation of the cap molecules. Stacking interaction has been discussed in detail in terms of the cap structural features, e.g., types of bases and length of the 5,5-phosphate bridges, and regarding the interactions stabilizing intramolecular stacking.

FM-Representability and beyond

This work concerns representability of arithmetical notions in finite models. It follows the paper by Marcin Mostowski [1], where the notion of FM–representability has been defined. We discuss how far this notion captures the methodological idea of representing infinite sets in finite but potentially infinite domains. n nWe consider mainly some weakenings of the notion of FM–representability. We prove that relations weakly FM–representable are exactly those being

Eukaryotic translation initiation is controlled by cooperativity effects within ternary complexes of 4E-BP1, eIF4E, and the mRNA 5′ cap

Sigma_{rm 2}^{rm 0}

An avian influenza H5N1 virus vaccine candidate based on the extracellular domain produced in yeast system as subviral particles protects chickens from lethal challenge

–definable. Another weakening of the notion, namely statistical representability, turns out to be equivalent to the original one. Additionally, we consider the complexity of sets of formulae naturally defined in finite models. We state that the set of sentences true in almost all finite arithmetical models is

Coprimality in finite models

Sigma_{rm 2}^{rm 0}

The strength of ramsey’s theorem for coloring relatively large sets

–complete and that the set of formulae FM–representing some relations is

Modeling of Dolichol Mass Spectra Isotopic Envelopes as a Tool to Monitor Isoprenoid Biosynthesis

Pi^{0}_{3}

A note on ramsey theorems and turing jumps

–complete.

Theories of initial segments of standard models of arithmetics and their complete extensions

Initiation is the rate‐limiting step during mRNA 5′ cap‐dependent translation, and thus a target of a strict control in the eukaryotic cell. It is shown here by analytical ultracentrifugation and fluorescence spectroscopy that the affinity of the human translation inhibitor, eIF4E‐binding protein (4E‐BP1), to the translation initiation factor 4E is significantly higher when eIF4E is bound to the cap. The 4E‐BP1 binding stabilizes the active eIF4E conformation and, on the other hand, can facilitate dissociation of eIF4E from the cap. These findings reveal the particular allosteric effects forming a thermodynamic cycle for the cooperative regulation of the translation initiation inhibition.