On the crystal geometry influence on the growth of fast-growing surfaces

The external morphology of a given crystal is determined by the growth conditions, growth time and geometry of the crystal. Up to now, it has been believed that the growth conditions which influence the relative growth rates of surfaces play the key role in the formation of the final crystal morphology. In this paper, it is shown that the geometry of a given crystal, expressed by the trigonometric function of appropriate interfacial angles, may influence to a great degree the crystallisation process and the morphology of crystals. For example, it is shown that at particular geometry of a crystal, a given surface may exist in the habit and develop its size although it grows much faster than the neighbouring surfaces.     

13C and 1H NMR spectral studies of N-alkylmethylquinolinium salts

¹³C and ¹H chemical shifts of fourteen N-alkylmethylquinolinium salts in DMSO-d₆ are reported, and compared with those of the eleven corresponding methylquinoline bases. The influence of ring substitution by methyl groups in the salts and substitution at the nitrogen atom and the effect of the anion are discussed.     

Introductive Backgrounds to Modern Quantum Mathematics with Application to Nonlinear Dynamical Systems

Introductive backgrounds to a new mathematical physics discipline—Quantum Mathematics—are discussed and analyzed both from historical and from analytical points of view. The magic properties of the second quantization method, invented by V. Fock in 1932, are demonstrated, and an impressive application to the nonlinear dynamical systems theory is considered. The Authors devote their article to their Friend and Teacher academician Prof. Anatoliy M. Samoilenko on occasion of his 70 years-Birthday with great compliments and gratitude to his brilliant talent and impressive impact to modern theory of nonlinear dynamical systems of mathematical physics and nonlinear analysis     

Adsorption of 1,2-diaminoethane on ZnO thin films from p-xylene

The interaction of 1,2-diaminoethane (DAE) with ZnO thin films prepared by electrodeposition and magnetron sputtering was investigated by X-ray photoelectron spectroscopy (XPS). The samples were exposed to organic solution of 0.5 M DAE-p-xylene in an Ar atmosphere glove box (O₂ and H₂O <5 ppm), directly connected to the XPS analysis chamber by an anaerobic and anhydrous transfer system. A clear interaction of DAE with the ZnO surface is evidenced by the presence of a high intensity N1s peak at BE = 399.5 ± 0.2 eV and C1s at BE = 286.3 ± 0.2 eV which are attributed to C-N bonding. The atomic ratio C:N was very close to 1:1 consistent with the molecular, non-dissociative adsorption of DAE on the ZnO layer. No significant difference in adsorption of DAE was observed for three different ZnO surfaces despite slight differences in their acid/base properties as evidenced by the O/OH ratio. The results are interpreted in terms of adsorption on Brönsted acid sites. A uniform layer model was used to approximate the DAE film thickness, which was found to be around 10 Å on three studied samples. The N1s and C1s_B signals were observed to decrease on sample exposure to vacuum and/or X-ray irradiation and additional N1s_B peak appeared at lower binding energy at around 398.5 ± 0.2 eV. This is interpreted by the desorption and modification of DAE, indicating low stability of the adsorbed state on ZnO. The exposure to water of the sample with adsorbed DAE causes a significant decrease of the N1s_A and C1s_B peak intensities attributed to the adsorbed DAE molecule, demonstrating the instability of the DAE-ZnO interface in water.     

Flocculation of Bacillus amyloliquefaciens H Disintegrates with Cationized Starch and Aminated Hydroxyethylcellulose

The ability of cationized hydroxyethylated starch (CHES) and aminated hydroxyethylcellulose (DEAE-HEC) to flocculate cell disintegrate of Bacillus amyloliquefaciens H (BamHI) was investigated. The efficiency of flocculation was compared to that of synthetic polymer polyethyleneimine (PEI) and natural polysaccharide chitosan. The influence of salt concentration and biomass concentration on flocculation efficiency was investigated. It was found that the efficiency of flocculation with CHES and DEAE-HEC was similar to that of PEI but better compared to chitosan. Recovery of total soluble proteins at higher than 0.3% concentration of flocculant decreased by more than 18.8% and 42.3% compared to PEI and chitosan, respectively. The yield of BamHI restriction endonuclease activity with all flocculants was similar except for chitosan where 13.1% lower yield was obtained. Meanwhile, efficiency of flocculation with CHES and DEAE-HEC depends drastically on the salt concentration, that is, flocculation diminishes if NaCl concentrations higher than 0.2 M (for CHES) or 0.1 M (for DEAE-HEC) are used. The results have shown that CHES and DEAE-HEC are promising flocculants of cell disintegrates if higher yield of protein is of great concern.     

Thio Analogs of Pyrimidine Bases: Syntheses,EIMS and 13 C NMR Study of New Ortho -( Meta - and Para -) Substituted Derivatives of 2-benzylthio-5-bromo-6-methyluracils

Nine new ortho -( meta - and para -) substituted derivatives of 2-benzylthio-5-bromo-6-methyluracils have been prepared. EI induced mass spectral fragmentation of these compounds was investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transitions measurements. The correlation between the intensities of the M +. and the selected fragment ions of these compounds is discussed. 13 C NMR spectra of these compounds were assigned. The data derived from EIMS and 13 C NMR spectra can be used to differentiate the isomers.     

Mechanisms of reaction in cytochrome P450: Hydroxylation of camphor in P450cam

The fundamental nature of reactivity in cytochrome P450 enzymes is currently controversial. Modelling of bacterial P450cam has suggested an important role for the haem propionates in the catalysis, though this finding has been questioned. Understanding the mechanisms of this enzyme family is important both in terms of basic biochemistry and potentially in the prediction of drug metabolism. We have modelled the hydroxylation of camphor by P450cam, using combined quantum mechanics/molecular mechanics (QM/MM) methods. A set of reaction pathways in the enzyme was determined. We were able to pinpoint the source of the discrepancies in the previous results. We show that when a correct ionization state is assigned to Asp297, no spin density appears on the haem propionates and the protein structure in this region remains preserved. These results indicate that the haem propionates are not involved in catalysis.     

Study on the rate of plutonium vertical migration in various soil types of Lublin region (Eastern Poland)

Soil contamination level with ^239+240Pu of Lublin region was determined using the alpha spectrometric method. Results were compared with similar data from the study performed 15 year earlier. Decrease in total ^239+240Pu concentration and reducing quantity of Chernobyl fraction (up to almost negligible value of 1 %) has been observed in upper soil layer. Determination of ^239+240Pu concentration in soil profile layers allows calculating a vertical migration velocity of plutonium applying a compartment migration model. It was found that ^239+240Pu migration rate varies depending on soil type from 0.29 cm year^?1 in Podsols to 0.58 cm year^?1 in Fluvisols with mean value of 0.5 cm year^?1.     

Cation dependence of chloride ion complexation by open-chained receptor molecules in chloroform solution

Seventeen peptides, most having the sequence GGGPGGG, but differing in the C- and N-terminal ends, have been studied as anion-complexing agents. These relatively simple, open-chained peptide systems interact with both chloride and the associated cation. Changes in the N- and C-terminal side chains appear to make little difference in the efficacy of binding. NMR studies suggest that the primary interactions involve amide NH contacts with the chloride anion, and CD spectral analyses suggest a concomitant conformational change upon binding. Changes in binding constants, which are expected in different solvents, also suggest selective solvent interactions with the unbound host that helps to preorganize the open-chained peptide system. Significant differences are apparent in complexation strengths when the heptapeptide chain is shortened or lengthened or when the relative position of proline within the heptapeptide is varied.