Complete assignment of the vibrational modes of C60 by inelastic neutron scattering spectroscopy and periodic-DFT

In this paper we exploit the complementarity of inelastic neutron scattering (INS), infrared and Raman spectroscopies with ab initio calculations to generate an updated assignment of the vibrational modes of C(60). We have carried out periodic-DFT calculations of the high temperature face centred cubic phase modelled as the standard structure and also of the low temperature simple cubic phase, the latter for the first time. Our assignment differs from all previous work, however, it is the only one that is able to successfully reproduce the INS spectrum in terms of both transition energies and intensities. In addition to the INS spectrum we are also able to quantitatively simulate the major features of the infrared and Raman spectra in the high temperature phase and the infrared spectrum in the low temperature phase.     

The study of the lipophilicity of some aminoalkanol derivatives with anticonvulsant activity

A series of new (phenoxyethyl)aminoalkanol derivatives were synthesized and evaluated for their anticonvulsant activity. The most promising compound seemed to be (R,S)‐1N‐[(2,6‐dimethyl)phenoxyethyl]amino‐2‐butanol, which displayed anti‐MES activity (in mice, i.p.) with protective index (TD₅₀/ED₅₀) of 5.712, corresponding to that of phenytoin (6.6), carbamazepine (4.9) and valproate (1.7). The lipophilicity of compounds 1–17 exhibiting anticonvulsant activity was investigated. Their lipophilicities (R_M0) were determined using reversed‐phase thin‐layer chromatography (RP‐TLC) with a mixture of acetone and water as mobile phases. The partition coefficients of 1–17 (logP) were also calculated using two computer programs (Pallas and ALOGPS) and compared with R_M0. The relationship between anticonvulsant activity and lipophilicity of the tested substances was estimated. Copyright © 2010 John Wiley & Sons, Ltd.     

Calorimetric studies of interactions of some peptides with electrolytes,urea and ethanol in water at 298.15 K

The standard molar enthalpies of solution at infinite dilution \Updelta_\textsol H_\textm^￥ \Updelta_{\text{sol}} H_{\text{m}}^{\infty } of glycylglycine, dl-alanyl-dl-alanine and glycylglycylglycine in aqueous solutions of potassium chloride and ethanol as well as of glycylglycine and glycylglycylglycine in the solutions containing urea and water have been determined by calorimetry at the temperature 298.15 K. Changes of solution enthalpy, expressed in a form so-called heterotactic interaction coefficients, h_\textxy h_{\text{xy}} were used for analysis of interactions occurring between the investigated solutes in water. The group contributions illustrating the interactions of KCl, urea and ethanol with selected functional groups in the peptide molecules, namely CH₂, “pep,” and “ion” groups, were calculated and discussed.     

Characterization of the quality of novel rye-buckwheat ginger cakes by chemical markers and antioxidant capacity

The total phenolics and flavonoids, rutin, early, advanced and final Maillard reaction products, and antioxidative capacity determined against 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) radical cation and superoxide anion radicals were used for the characterization of the quality of novel rye-buckwheat ginger cakes enriched with rutin (quercetin rutinoside). The cakes were prepared substituting 30 % of rye flour by light buckwheat flour or flour from roasted buckwheat dehulled grains and employing a dough fermentation-like incubation step. Enrichment of ginger cakes with rutin showed protective effect on lysine blockage, improved antioxidant properties, inhibited the formation of furosine and free fluorescent compounds thus stimulating the Maillard reaction progress towards melanoidin formation. The loss of the nutritional quality of cakes enriched with rutin was related to the formation of fluorescent compounds linked to protein and carboxymethyllysine at an advanced stage of the Maillard reaction. It can be concluded that free fluorescence intermediatory compounds, carboxymethyllysine and browning are the best chemical markers for the characterization of the quality of this novel type of ginger cakes. This study also indicates that rye-buckwheat ginger cakes enriched with rutin can be recommended for wider consumption since daily consumption of 250 g of these cakes may have a prophylactic or therapeutic effect corresponding to typical pharmacological drugs with rutin as the active component.     

Is planarity of pyridin-2-yl- and pyrazin-2-yl-formamide thiosemicarbazones related to their tuberculostatic activity? X-ray structures of two pyrazine-2-carboxamide-N′-carbonothioyl-hydrazones

Crystal structures of two title compounds and several their relatives known earlier reveal conservative and characteristic features, which may be related to their tuberculostatic activity. The molecules are predominantly planar due to conjugation through five successive bonds in the zwitterionic fragment S⁻–C(sp²)–N–NH⁺–C(sp²)–NH₂ and intramolecular hydrogen bonds, which prevent rotation of the adjacent pyrazine (or pyridine) ring. It has been suggested that in spatial sense such planar molecules resemble acridines intercalating with nucleic acids and that similar process may be responsible for tuberculostatic activity of the title pyrazine-2-carboxamide-N′-carbonothioyl-hydrazones.     

Fine tuning the structure of the Cu2+ complex with the prion protein chicken repeat by proline isomerization

The interaction between the single hexarepeat unit of chicken prion protein [ChPrP(54-59)] and Cu(II) was investigated by NMR, finding different coordination modes for the trans/trans and cis/trans isomers.     

Microscopically structural studies of lithium niobate powders

On the basis of the crystallographic characteristics of lithium niobate (LN) crystals, Law of Bravais and Pauling's third rule (i.e. Polyhedral Sharing Rule) are employed with the aim to find the relationship between the crystal structure and morphological faces of LN powders. In order to validate our analytical results, we have successfully synthesized LN powders and measured the corresponding X-ray powder diffraction. Our results show that the structural analysis is consistent with the experimental data and is helpful and effective for us to control the single-crystal growth and to design superstructures at the specific plane, starting from the viewpoint of the microscopic behaviors of constituent chemical bonds and polyhedra in the crystallographic frame.     

Frequency-domain fluorescence spectroscopy, a new method for the resolution of complex fluorescence emission

The fluorescence emission from complex chemical and biological samples can be resolved by measuring the frequency-response of the emission, which is now possible from 1 to 2000 MHz. The frequency-response allows determination of the components in a mixture, construction of time-resolved emission spectra, and measurement of the dynamic and hydrodynamic properties of biological macromolecules. The instrumentation is relatively simple, and data acquisition times can be short. At present, this method may be superior to direct measurements of time-resolved fluorescence emission.