Entanglement in a three spin system controlled by electric and magnetic fields

We study the effect of electric field and magnetic flux on spin entanglement in an artificial triangular molecule built of coherently coupled quantum dots. In a subspace of doublet states an explicit relation of concurrence with spin correlation functions and chirality is presented. The electric field modifies superexchange correlations and shifts many-electron levels (the Stark effect), as well as changing spin correlations. For some specific orientation of the electric field one can observe monogamy, for which one of the spins is separated from two others. Moreover, the Stark effect manifests itself in a different spin entanglement for small and strong electric fields. The role of magnetic flux is opposite: it leads to circulation of spin supercurrents and spin delocalization.     

Cantor extension of an abelian lattice ordered group equipped with a weak relatively uniform convergence

The notion of weak relatively uniform convergence (wru-convergence, for short) on an abelian lattice ordered group G has been investigated in a previous authors?? article. In the present paper we deal with Cantor extension of G and completion of G with respect to a wru-convergence on G.     

Torsion classes of generalized Boolean algebras

Torsion classes and radical classes of lattice ordered groups have been investigated in several papers. The notions of torsion class and of radical class of generalized Boolean algebras are defined analogously. We denote by T _g and R _g the collections of all torsion classes or of all radical classes of generalized Boolean algebras, respectively. Both T _g and R _g are partially ordered by the class-theoretical inclusion. We deal with the relation between these partially ordered collection; as a consequence, we obtain that T _g is a Brouwerian lattice. W. C. Holland proved that each variety of lattice ordered groups is a torsion class. We show that an analogous result is valid for generalized Boolean algebras.     

In vitro inhibitory activity of essential oil vapors against Ascosphaera apis

This work evaluates the in vitro inhibitory activity of 70 essential oils (EOs) in the vapor phase for the control of Chalkbrood disease caused by Ascosphaera apis Maassen ex Claussen (Olive et Spiltoir). Two wild strains isolated from infected honey bee colonies together with one standard collection strain were tested by the microatmosphere method. From 70 EOs, 39 exhibited an antifungal effect against A. apis standard and wild strains. The greatest antifungal action was observed for EO vapors from Armoracia rusticana, followed by Thymus vulgaris, Cymbopogon flexosus, Origanum vulgare and Allium sativum. An investigation of chemical composition by GC-MS revealed, that the most active EOs contained allyl isothiocyanate, citral, carvacrol and diallyl sulfides as the main constituents. The chemical composition plays a key role, as activities of different EOs from the same botanical species were different according to their composition.     

The role of a conserved threonine residue in the leader peptide of lasso peptide precursors

The conserved threonine (Thr) residue in the penultimate position of the leader peptide of lasso peptides microcin J25 and capistruin can be effectively replaced by several amino acids close in size and shape to Thr. These findings suggest a model for lasso peptide biosynthesis in which the Thr sidechain is a recognition element for the lasso peptide maturation machinery.     

Thermodynamics of translesion synthesis across a major DNA adduct of antitumor oxaliplatin: differential scanning calorimetric study

Differential scanning calorimetry (DSC) was used to measure the thermodynamic changes associated with translesion synthesis across major lesion induced in DNA by antitumor oxaliplatin [1,2-d(GG) intrastrand cross-link]. Insertion of matched nucleotides dC at the primer terminus (across unique 3'- or 5'-dG in the unplatinated template) and subsequent extensions resulted in an incremental increase in thermodynamic parameters. In contrast, incorporation of dC opposite either platinated dG in the intrastrand cross-link formed in the template strand and subsequent extensions by one nucleotide resulted only in little changes in thermodynamics. A similar thermodynamic delay was observed for a control template primer containing a dG:dT mismatch across 3'- or 5'-dG in the template and subsequent Watson-Crick primer extensions. The thermodynamic scarcity generated by either the lesion or mismatches was not localized but extended to the 5'-downstream sites, which may be connected with the phenomenon termed "short-term memory" of replication errors retained by some DNA polymerases responding to DNA damages or mismatches. Interestingly, formation of the 1,2-d(GG) intrastrand cross-link of oxaliplatin altered the overall DSC profiles of the dG:dT mismatch template/primers only in a very small extent. While addition of matched nucleotide dC across either dG in the template strand was thermodynamically favored over the presence of a mismatched dT (ΔΔG(0)(310) was 7.6 or 6.8 kJ mol(-1), ΔΔH was 14 or 49 kJ mol(-1)), no such thermodynamic advantage was observed with the 1,2-d(GG) intrastrand cross-link of oxaliplatin at these positions (ΔΔG(0)(310) was 2.8 or -0.3 kJ mol(-1), ΔΔH was 4 or 9 kJ mol(-1)). The equilibrium thermodynamic data also provide insight into the processes associated with misincorporation of incorrect nucleotides during replication bypass across major cross-links of antitumor oxaliplatin. On the other hand, besides thermodynamic effects also kinetic factors play an important role in the processing of the cross-links of antitumor platinum drugs. The impact of the two effects in overall processing DNA adducts by a particular DNA polymerase will depend on its nature.     

Random sequential adsorption on fractals

Irreversible adsorption of spheres on flat collectors having dimension d < 2 is studied. Molecules are adsorbed on Sierpinski's triangle and carpet-like fractals (1 < d < 2), and on general Cantor set (d < 1). Adsorption process is modeled numerically using random sequential adsorption (RSA) algorithm. The paper concentrates on measurement of fundamental properties of coverages, i.e., maximal random coverage ratio and density autocorrelation function, as well as RSA kinetics. Obtained results allow to improve phenomenological relation between maximal random coverage ratio and collector dimension. Moreover, simulations show that, in general, most of known dimensional properties of adsorbed monolayers are valid for non-integer dimensions.     

Synthesis and antimicrobial evaluation of new 1‐{[4‐(4‐Halogenophenyl)‐4H‐1,2,4‐ triazol‐3‐yl]sulfanyl}acetyl‐4‐substituted thiosemicarbazides and products of their cyclization

By the reaction of hydrazides of 4‐(4‐halogenophenyl)‐4H‐1,2,4‐triazol‐3‐yl‐sulfanyl acetic acid with isothiocyanate, 1‐acyl‐4‐substituted thiosemicarbazide derivatives ( 7–19 ) were obtained. The cyclization of compounds ( 7–19 ) in the presence of 2% NaOH led to the formation of compounds ( 20–26 ) containing two 1,2,4‐triazole rings connected by a methylenesulfanyl group. The new compounds were tested for their in vitro antimicrobial activity. Some of the tested compounds ( 9, 12, 18, 21, 22 ) showed activity against the reference strains of Gram‐positive bacteria with the MIC (minimal inhibitory concentration) = 125 to >1000 μg/mL. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:117–121, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20758     

Fe-N-C catalysts for oxygen electroreduction under external magnetic fields:Reduction of magnetic O2 to nonmagnetic H2O

An extensive analysis of iron-nitrogen-carbon(Fe-N-C)electrocatalysts synthesis and activity is presented concerning synthesis conditions such as initial Fe content,pyrolysis temperature and atmosphere(inert N₂,reducing NH₃,oxidizing Cl₂ and their sequential combinations)and the influence of an external magnetic field on their performance in oxygen reduction reaction(ORR).Thermosetting porous polymers doped with FeCl₃ were utilized as the Fe-N-C catalysts precursors.The pyrolysis temperature was varied within a 700-900℃range.The temperature and atmosphere of pyrolysis strongly affect the porosity and compositi on of the resultant Fe-N-C catalysts,while the in itial amount of Fe precursor shows much weaker impact.Pyrolysis under NH₃ yields materials similar to those pyrolyzed under an inert atmosphere(N₂).In contrast,pyrolysis under Cl₂ yields carbon of peculiar character with highly disordered structure and extensive microporosity.The application of a static external magnetic field strongly enhances the ORR process(herein studied in an alkaline environment)and the enhancement correlates with the Fe content in the Fe-N-C catalysts.The Fe-N-C materials containing ferromagnetic iron phase embedded in N-doped microporous carbon constitute attractive catalysts for magnetic field-aided anion exchange membrane fuel cell technology.     

Electrochemical Analysis of Glycoprotein Samples Prepared on a Pneumatically‐controlled Microfluidic Device

In this work, we designed and manufactured a microfluidic device for isolation and purification of glycoprotein samples. The conceived sample preparation device was fabricated in polycarbonate by micro‐milling. The flow control and the fluid dosage into the micro‐channels was solved by equipping the device with integrated pneumatic valves. The biochemical functionality was provided by beaded support modified by molecules with affinity to glycoproteins which was stacked inside the micro‐channel reminiscent of packed affinity columns used in glycoprotein lectin assays. Unlabeled glycoproteins, namely fetuin, asialofetuin, and prostate‐specific antigen, were voltammetrically analyzed using catalytic peak H at silver amalgam electrode.