Compactly Generated de Morgan Lattices, Basic Algebras and Effect Algebras

We prove that a de Morgan lattice is compactly generated if and only if its order topology is compatible with a uniformity on L generated by some separating function family on L. Moreover, if L is complete then L is (o)-topological. Further, if a basic algebra L (hence lattice with sectional antitone involutions) is compactly generated then L is atomic. Thus all non-atomic Boolean algebras as well as non-atomic lattice effect algebras (including non-atomic MV-algebras and orthomodular lattices) are not compactly generated.     

Sharp Elements in Effect Algebras

We show that if for an arbitrary pair of orthogonal sharp elements of an effect algebra E its join exists and is sharp, then the set E_S of all sharp elements of E is a subeffect algebra of E that is an orthomodular poset. Such effect algebras need not be sharply dominating but S-dominating. Further, we show that in every nonproper effect algebra E, E_S is a subeffect algebra that is an orthomodular poset. Moreover, a general theorem for E_S is proved.     

On the photochemical dimerization of some 5‐substituted 2‐styryl‐4‐pyrones. The effect of 5‐hydroxy‐/ 5‐methoxy‐substitution

Irradiation of styryl‐4‐pyrones 1a‐1d or 2a‐2e (6‐9 × 10^?3 M, methanol solution) with filtered (RAYONET photochemical reactor, 300 nm) or unfiltered uv‐light (high‐pressure mercury arc lamp) under aerobic conditions led mainly to dimeric products. Parent 5‐hydroxy‐substituted compounds 1a‐1d yielded exclusively “half‐cage” dimers 3a‐d characteristic for 4‐pyrone dimerization. 5‐Methoxy‐analogues 2a‐2e behave like typical stilbene structures and the mixture of tetrasubstituted cyclobutanes 4 and 5 accompanied with minor amount of phenanthrene‐like compound 6 were the only isolable products of the irradiation. The structure elucidation of products is based on spectral data obtained from MS, IR, ¹H NMR and ¹³C NMR spectra applying COSY, APT, HETCOR, HMBC and NOESY techniques.     

Preliminary study on the monitoring of glutathione S-tranferase activity toward styrene oxide by electromigration methods

A new method has been developed for the monitoring of glutathione S-tranferase (GST) detoxification activity toward styrene oxide (SO). The enzymatic reaction was carried out directly in a thermostatted autosampler vial and the formation of conjugates between glutathione (GSH) and SO was monitored by sequential MEKC runs. The determinations were performed in a 50-microm fused silica capillary using 50 mM SDS in 20 mM phosphate 20 mM tetraborate buffer (pH 8.3) as a background electrolyte; separation voltage 28 kV (positive polarity), temperature of capillary 25 degrees C, and detection at 200 nm. The method is rapid, amenable to automation, and requires only small amounts of samples, which is especially important in the case of GST isoenzyme analyses.     

Amination of naphthoquinones with azidotrimethylsilane

A new method for the synthesis of aminonaphthoquinones from 1,2- or 1,4-naphthoquinones and azidotrimethylsilane is described. In a similar manner 2,3-epoxy-2,3-dihydro-1,4-naphthoquinone was transformed into 2-amino-3-hydroxy-1,4-naphthoquinone. The mechanism of these transformations and the formation of by-products are discussed.

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Aminierung von Naphthochinonen mit Azidotrimethylsilan

Zusammenfassung Eine neue Methode zur Herstellung von Aminonaphthochinonen aus 1,2- oder 1,4-Naphthochinonen und Azidotrimethylsilan wird beschrieben. In analoger Weise wurde 2,3-Epoxy-2,3-dihydro-1,4-naphthochinon in 2-Amino-3-hydroxy-1,4-naphthochinon umgewandelt. Eine mechanistische Deutung dieser Umsetzung und die Bildung von Nebenprodukten wird diskutiert.

     

Assessment of elemental mobility in soil using a fluidised bed approach with on-line ICP-MS analysis

A new method has been developed to analyse the mobility of elements within soils employing counter-current flow soil contacting in a fluidised bed (FB) column. This method alleviates the problem of irreproducible peaks suffered by state-of-the-art micro-column techniques as a result of particle compaction. Reproducible extraction profiles are produced through the leaching of soil with a linear gradient of 0.05 mol L⁻¹ ammonium sulphate to 0.11 mol L⁻¹ acetic acid using a high pressure liquid chromatography (HPLC) quaternary pump, and the continuous monitoring of the elements in the leachate with inductively coupled plasma mass spectrometry (ICP-MS). Quantification of the procedure is achieved with an external flow injection (FI) calibration method.Flow rate and FB column length were investigated as critical parameters to the efficiency of the extraction methodology. It was found that an increase in the column length from 10 to 20 cm using a flow rate of 0.15 mL min⁻¹ produced the same increase in extracted elemental concentration as an increase in flow rate from 0.15 to 0.30 mL min⁻¹. In both examples, the increase in the concentration of elements leached from the soil may be ascribed to the increase in the concentration gradient between the solid and liquid.The exhaustive nature of the technique defines the maximum leachable concentration within the operationally defined leaching parameters of the exchangeable phase, providing a more accurate assessment of the risk associated with the elements in the soil for the phase providing the greatest risk to the environment.The multi-elemental high sensitivity nature of the on-line detector provides an accurate determination of the associations present between the elements in the soil, and the identification of multiple phases within the exchangeable phase through the presence of multiple peaks in the extraction profiles. It is possible through the deconvolution of these extraction profiles that the concentration corresponding to the peaks identified can be defined.     

Optimization of Affinity Chromatography of Pepsins on Iodinated l-Tyrosine–Sepharose

Iodinated l-tyrosine–Sepharose was used as an affinity sorbent for the separation of porcine and human pepsins. The optimized conditions for pepsin adsorption as well as enzyme desorption were investigated. The following basic characteristics of the prepared affinity sorbent were determined: the recovery of the loaded enzyme, capacity of the affinity sorbent, concentration range of the linear dependence of bound pepsin on the applied enzyme, and the reproducibility of the experiments. The method described here cannot only be used for pepsin separation but also for analytical purposes.

     

The meaning of computer search in the study of some classes of IM-quasigroups

The IM-quasigroup C(q) for or is a GS-quasigroup. Some interesting geometric concepts can be introduced in a general GS-quasigroup and their nice geometric representations can be given in the mentioned GS-quasigroup which justifies the research of this quasigroup. The concept of a parallelogram can be defined by means of several equivalent formulae. Some of them can be obtained by means of a computer. We shall choose a suitable formula for the definition of a parallelogram which allows the characterization of GS-quasigroups by means of commutative groups.      

Mean Field Theory of Self-Organizing Memristive Connectomes

Biological neuronal networks are characterized by nonlinear interactions and complex connectivity. Given the growing impetus to build neuromorphic computers, understanding physical devices that exhibit structures and functionalities similar to biological neural networks is an important step toward this goal. Self-organizing circuits of nanodevices are at the forefront of the research in neuromorphic computing, as their behavior mimics synaptic plasticity features of biological neuronal circuits. However, an effective theory to describe their behavior is lacking. This study provides for the first time an effective mean field theory for the emergent voltage-induced polymorphism of circuits of a nanowire connectome, showing that the behavior of these circuits can be explained by a low-dimensional dynamical equation. The equation can be derived from the microscopic dynamics of a single memristive junction in analytical form. The effective model is tested on experiments of nanowire networks and show that it fits both the potentiation and depression of these synapse-mimicking circuits. It is shown that this theory applies beyond the case of nanowire networks by formulating a general mean-field theory of conductance transitions in self-organizing memristive connectomes.     

Optimization of Affinity Chromatography of Pepsins on Iodinated <Emphasis Type="SmallCaps">l</Emphasis>-Tyrosine–Sepharose

Iodinated l-tyrosine–Sepharose was used as an affinity sorbent for the separation of porcine and human pepsins. The optimized conditions for pepsin adsorption as well as enzyme desorption were investigated. The following basic characteristics of the prepared affinity sorbent were determined: the recovery of the loaded enzyme, capacity of the affinity sorbent, concentration range of the linear dependence of bound pepsin on the applied enzyme, and the reproducibility of the experiments. The method described here cannot only be used for pepsin separation but also for analytical purposes.