Unusual structures derived from N‐acridin‐9‐yl methyl N′‐acridin‐9‐yl thiourea based on the propensity of N‐10 to retain H

N‐Acridin‐9‐yl methyl N′‐acridin‐9‐yl thiourea spontaneously spiro cyclises via nucleophilic attack of the methylene carbon onto the C‐9 of the other acridine moiety. The thiourea, upon reaction with bromoacetonitrile, provided a spiro fused‐bicyclic product displaying unusual dynamic behavior.     

Immobilization in biotechnology and biorecognition: from macro- to nanoscale systems

Biological molecules such as enzymes, cells, antibodies, lectins, peptide aptamers, and cellular components in an immobilized form are extensively used in biotechnology, in biorecognition and in many medicinal applications. This review provides a comprehensive summary of the developments in new immobilization materials, techniques, and their practical applications previously developed by the authors. A detailed overview of several immobilization materials and technologies is given here, including bead cellulose, encapsulation in ionotropic gels and polyelectrolyte complexes, and various immobilization protocols applied onto surfaces. In addition, the review summarises the screening and design of an immobilization protocol, practical applications of immobilized biocatalysts in the industrial production of metabolites, monitoring, and control of fermentation processes, preparation of electrochemical/optical biosensors and biofuel cells.     

Influence of the ionic form of a cation-exchange adsorbent on chromatographic separation of galactooligosaccharides

Separation performance of sodium, lithium, potassium and hydrogen ionic forms of a commercial cation exchanger, Diaion UBK 530, based on a styrene-divinylbenzene copolymer resin support was studied. The adsorbents were applied to the separation of galactooligosaccharides from their mixture with lactose, glucose and galactose. Separation performance of the hydrogen ionic form of the adsorbent was superior to that of other adsorbent forms. A much higher yield of galactooligosaccharides of the requested purity was achieved for this adsorbent form owing to its better kinetic properties. Adsorption properties of individual adsorbents were discussed in relation to possible adsorption mechanisms.     

Heredity and Coreflective Subcategories of the Category of Topological Spaces

Every hereditary coreflective subcategory of Top containing the category of finitely-generated spaces is shown to be generated by a class of spaces having a unique accumulation point. It is also shown that the coreflective hull of a union of two hereditary coreflective subcategories of Top need not be hereditary so that a coreflective subcategory of Top need not have a hereditary coreflective kernel.     

Modeling of saccharide utilization in primary beer fermentation with yeasts immobilized in calcium alginate

Immobilized beer fermentation was studied using an industrial bottom-fermenting yeast strain Saccharomyces cerevisiae. The yeast cells were immobilized in 2.5% calcium alginate gel and used for brewing in a five-vessel cascade reactor. The fermentation was performed at 15°C at various flow rates. A nonstructured mathematical model was developed to simulate the performance of continuous primary fermentation of lager beer. The model was based on the following variables: maltose, maltotriose, glucose, fructose, ethanol, and cell concentration. Experimental values of these variables were determined in samples taken at regular intervals. For experimental data fitting a nonlinear regression was used. Substrate consumption was characterized by specific substrate consumption rate and saturation constant. The values of these two parameters were optimized for all four substrates. Inhibition effects of substrates and product were analyzed using various inhibition patterns. Only the inhibition effect of maltose on maltose consumption was clearly identified. A good-fitting relationship for maltose inhibition was found, and inhibition constants were calculated.     

Monomers for Adhesive Polymers, 6

Summary: 1,3‐Bis(methacrylamido)propane‐2‐yl dihydrogen phosphate ( 1 ) was synthesised by phosphorylation of 1,3‐bis(methacrylamido)‐2‐hydroxypropane ( 2 ) with phosphorus oxychloride in tetrahydrofuran (THF) in the presence of triethylamine (TEA). The structure of the new monomer 1 was characterised by IR, ¹H NMR, ¹³C NMR and ³¹P NMR spectroscopies, elemental analysis and mass spectrometry. The monomer dissolves well in water, ethanol or aqueous THF and shows an improved hydrolytic stability compared to the corresponding methacrylate‐based dihydrogen phosphates. 1 was homopolymerised in ethanol with 2,2′‐azoisobutyronitrile (AIBN) as the initiator at 55–75 °C under the formation of an insoluble, cross‐linked product. Aqueous solutions of 1 are strongly acidic and enable to etch enamel and dentin. Nevertheless, 1 did not show any cytotoxic effect. Furthermore, the adhesive properties of 1 were measured.

1,3‐Bis(methacrylamido)propane‐2‐yl dihydrogen phosphate.     

2-Ketogluconic acid production by acetobacter pasteurianus

Production of 2-ketogluconic acid in batch fermentation was investigated.Acetobacter pasteurianus ATCC 6438, which produces selectively 2-ketogluconic acid only, was used. The optimal pH for glucose dehydrogenation to gluconate by resting cells was 5.0 and for gluconate dehydrogenation to 2-ketogluconate 4.25. When glucose medium was used, the 89% yield was achieved after 90 h. For the optimal productivity, medium containing glucose and gluconate with the molar glucose:gluconate ratio 7.4 was proposed, and the yield of 92% after 56 h was achieved. This composition of medium led to the elevation of dissolved oxygen concentration during fermentation. It consequently resulted in elevated gluconate dehydrogenase activity being discussed as the rate-limiting activity of the batch production.     

Hexakis[tris­(ethyl­ene­diamine‐κ2N,N′)nickel(II)] tricyano­cuprate(I) bis­{μ‐cyano‐bis­[tricyano­cuprate(I)]} nona­hydrate

The title compound, [Ni(C₂H₈N₂)₃]₆[Cu(CN)₃][Cu₂(CN)₇]₂·9H₂O, was formed upon dissolution of a freshly prepared precipitate of CuNi(CN)₄ in ethyl­ene­diamine (en) as a result of complex redox and complexation equilibriums in the presence of air. The compound exhibits an ionic structure and contains three crystallographically independent chiral [Ni(en)₃]²⁺ cations, planar [Cu(CN)₃]²⁻ and chiral [(NC)₃Cu–(μ‐CN)–Cu(CN)₃]⁵⁻ anions, and water mol­ecules of crystallization. All metal atoms are situated on special positions. One of the Ni atoms lies on a twofold axis, whereas all other metal atoms are located on threefold axes.     

Harnack inequality and exponential separation for oblique derivative problems on Lipschitz domains

We consider the oblique derivative problem for linear nonautonomous second order parabolic equations with bounded measurable coefficients on bounded Lipschitz cylinders. We derive an optimal elliptic-type Harnack inequality for positive solutions of this problem and use it to show that each positive solution exponentially dominates any solution which changes sign for all times. We show several nontrivial applications of both the exponential estimate and the derived Harnack inequality.     

Closed structures on categories of topological spaces

The category of all topological spaces and continuous maps and its full subcategory of all T_o-spaces admit (up to isomorphism) precisely one structure of symmetric monoidal closed category (see [2]). In this paper we shall prove the same result for any epireflective subcategory of the category of topological spaces (particularly e.g. for the categories of Hausdorff spaces, regular spaces, Tychonoff spaces).