Molecule-solid interaction: Electronic states of anthracene-9-carboxylic acid adsorbed on the surface of TiO2

Electronic excited states of athracene-9-carboxylic acid chemisorbed on the surface of TiO₂ nanoparticles were investigated by means of the electroabsorption (Stark effect) spectroscopy at low temperature. In addition to a fraction of molecules adsorbed with no significant spectral changes, two forms absorbing at lowered energy (25,600 cm⁻¹ and 24,900 cm⁻¹) were observed, that exhibit a large increase in the excited-minus-ground state dipole moments, 2.7 D and 9.5 D, respectively, as well as changed molecular polarizabilities. The dipole moments are interpreted as indicators of partial charge-transfer character of the excited state, corresponding to the optical electron transfer from the adsorbate onto TiO₂ concomitantly with the photon absorption. Consequences of these observations are shortly discussed in the context of the electron transfer process in dye-sensitized solar cells.     

Guanine alkylation by ethylene oxide: calculation of chemical reactivity

In this paper we report on calculations of the activation free energy for a chemical reaction between ethylene oxide and guanine. Ethylene oxide is biologically relevant per se and is also a model compound for numerous ultimate carcinogens. Calculations were performed on the medium-high ab initio, DFT, and semiempirical MO levels. Effects of solvation were considered using the Langevine dipole method and solvent reaction field method of Tomasi and co-workers. The calculated activation free energies are in reasonable agreement with the experimental value.     

Arzelà's Theorem and strong uniform convergence on bornologies

In 1883 Arzelà (1983/1984) [2] gave a necessary and sufficient condition via quasi-uniform convergence for the pointwise limit of a sequence of real-valued continuous functions on a compact interval to be continuous. Arzelà's work paved the way for several outstanding papers. A milestone was the P.S. Alexandroff convergence introduced in 1948 to tackle the question for a sequence of continuous functions from a topological space (not necessarily compact) to a metric space. In 2009, in the realm of metric spaces, Beer and Levi (2009) [10] found another necessary and sufficient condition through the novel notion of strong uniform convergence on finite sets. We offer a direct proof of the equivalence of Arzelà, Alexandroff and Beer-Levi conditions. The proof reveals the internal gear of these important convergences and sheds more light on the problem. We also study the main properties of the topology of strong uniform convergence of functions on bornologies, initiated in Beer and Levi (2009) [10].     

Cyclic water pentamers in triclinic crystals of brucinium l‐glycerate

Brucinium l ‐glycerate 4.75‐hydrate, C₂₃H₂₇N₂O₄⁺·C₃H₅O₄⁻·4.75H₂O, was obtained by racemic resolution of dl ‐glyceric acid. This is the first report of triclinic crystals containing brucine. The water and l ‐glycerate anions form tapes built up of pentamers formed by water and carboxy O atoms, and this appears to be the reason for the low symmetry of the crystal.     

Effects of interaction of tannins with co-existing substances. VII. Inhibitory effects of tannins and related polyphenols on xanthine oxidase

The inhibitory effects of hydrolyzable tannins, condensed tannins and related polyphenols on the activity of xanthine oxidase (XOD), catalyzing uric acid formation from xanthine, were investigated. Marked differences in the strength of the inhibition were observed. Some of the differences among the monomeric hydrolyzable tannins were due to their molecular weights, reflecting the number of phenolic hydroxyl groups in the molecule. However, the inhibitory activity of several oligomeric hydrolyzable tannins seemed particularly low in spite of their large molecular size. It was also observed that differences in location of acyl groups on the carbohydrate cores caused differences in the inhibitory activity among monomeric and oligomeric hydrolyzable tannins. A caffeic acid derivative (caffeetannin), 3,5-di-O-caffeoylquinic acid (24), also inhibited this enzyme. Galloylation and the degree of polymerization in proanthocyanidins were also shown to affect remarkably the strength of the inhibition. Among the compounds tested in the present study, valoneic acid dilactone (29), isolated from Mallotus japonicus, inhibited the enzyme most effectively. A kinetic study showed that this dilactone inhibited XOD non-competitively. Comparison of the inhibitory effect on XOD, with the binding activity to hemoglobin, for each tannin, suggests that their inhibition of XOD is not based on non-specific binding to the protein. Similar comparison of the inhibitory effect on XOD with the inhibitory effect on the generation of superoxide anion radical (O2-.) from the hypoxanthine-XOD system revealed that the inhibition of O2-. generation by tannins is due to their radical-scavenging activity, and not due to their inhibitory activity upon the enzyme.     

The nil radical of power series rings

We describe the nil radical of power series rings in non-commuting indeterminates by showing that a series belongs to the radical if and only if the ideal generated by its coefficients is nilpotent. We also show thatt the principal ideals generated by elements of the nil radical of the power series ring in one indeterminate are nil of bounded index.     

Effect of Added Brewer’s Spent Grain on the Baking Value of Flour and the Quality of Wheat Bread

This study was undertaken to determine the effect of the partial replacement of wheat flour (WF) with barley brewer’s spent grain (BBSG) and barley-buckwheat brewer’s spent grain (BBSG + B) on dough quality and bread properties, including nutritional value. The contents of brewer’s spent grain (BSG) in the blend with wheat flour were 0, 10, and 20%. The quality of the flour blends was assessed with intermediate methods and based on laboratory baking. Analyses were also carried out to determine contents of basic nutrients and energy value. The replacement of part of wheat flour with BBSG and BBSG + B diminished gluten yield and deteriorated its quality (a decreased sedimentation value and stability, and increased dough softening). Changes were also observed in the starch-enzymatic system, resulting in a decreased falling number and maximum paste viscosity. Breads containing both BSG types featured higher yield and lower loaf volume. They had also higher contents of protein, dietary fibre, fat, and ash as well as a lower energy value compared to the wheat bread. Considering the organoleptic traits of breads, the 10% replacement of wheat flour with BSG is recommended in the blend. The BBSG + B was found to elicit more beneficial effects on bread properties than BBSG.     

Jacobson radical algebras with Gelfand-Kirillov dimension two over countable fields

It is shown that for every countable field K, there is a finitely generated graded Jacobson radical algebra over K of Gelfand-Kirillov dimension two. Examples of finitely generated Jacobson radical algebras of Gelfand-Kirillov dimension two over algebraic extensions of finite fields of characteristic 2 were earlier constructed by Bartholdi [L. Bartholdi, Branch Rings, thinned rings, tree enveloping rings, Israel J. Math. (in press)].     

The use of atmospheric pressure laser desorption mass spectrometry for the study of iron-gall ink

The study of ancient works of art is a very challenging task, mainly due to the impossibility of applying experimental approaches that could damage anyhow the object from which analytical information has to be obtained. Spatially resolved analytical methods have significantly enhanced our capacity to study ancient material since they cause minimal and at times no damage to the studied object. Unfortunately, only a few analytical techniques operating within the requested spatial resolution are applicable for the investigation of the organic components of artistic and archaeological objects. In this work, iron-gall ink was prepared according to ancient recipes and its composition was evaluated by AP/MALDI-MS. The latter is demonstrated to be a very valuable tool for the study of the organic components of ancient works of art as it combines the advantages of the vacuum MALDI-MS analytical approach to the possibility of analysing samples in air. In situ analyses were also carried out by analysing strokes of ink directly from paper and parchment. PACS 82.80.Ms; 61.66.Hq; 87.14.-g     

On the Fourier transform of SO(d)-finite measures on the unit sphere

The paper presents a simple new approach to the problem of computing Fourier transforms of SO(d)-finite measures on the unit sphere in the euclidean space. Representing such measures as restrictions of homogeneous polynomials we use the canonical decomposition of homogeneous polynomials together with the plane wave expansion to derive a formula expressing such transforms under two forms, one of which was established previously by F. J. Gonzalez Vieli. We showthat equivalence of these two forms is related to a certain multi-step recurrence relation for Bessel functions, which encompasses several classical identities satisfied by Bessel functions. We show it leads further to a certain periodicity relation for the Hankel transform, related to the Bochner- Coifman periodicity relation for the Fourier transform. The purported novelty of this approach rests on the systematic use of the detailed form of the canonical decomposition of homogeneous polynomials, which replaces the more traditional approach based on integral identities related to the Funk-Hecke theorem. In fact, in the companion paper the present authors were able to deduce this way a fairly general expansion theorem for zonal functions, which includes the plane wave expansion used here as a special case.Received: 7 May 2004; revised: 11 October 2004