On the regular part of varieties of algebras

We show that the regular part of a variety of algebras may not consist entirely of subalgebras of Plonka sums; indeed, the latter may not be closed under homomorphic images. In addition we give an example of a finitely based variety whose regular part has no finite basis (but is finitely based in a different similarity type).Our examples contrast with known results for semigroups, and contradict a published claim for the general case.To the memory of András HuhnPresented by Boris Schein.     

The Synthesis of 1,4,7,10-Tetraazacyclododecanes with Acetylsalicylic Side Arm as Potential Cobalt(II) Fluorophores

New derivatives of 1,4,7,10-tetraazacyclododecanes have been synthesized. The coordination properties toward Co²⁺ of these ligands have been studied by means of spectroscopic methods. The stability constants of cobalt complexes with ligand L-1 and L-2were determined. Unusual complexes with a 2:1 (L:Co²⁺) stoichiometry have been found.     

Analysis of spectral data by complementary methods. Inspection of the molecular complex in N,N-dimethylformamide-methanol mixtures

FT-IR spectra of N,N-dimethylformamide (DMF)-methanol (MeOH) mixtures have been measured in the range of 4000-950 cm(-1). The data have been analyzed using the difference spectra method and factor analysis. The usefulness of the methods for recognizing the hydrogen bonds in the mixtures has been critically examined. It has been shown that 1:1 intermolecular complex existing in the whole range of the mixture composition is modified by interactions with environment. The structure of different forms of the complex depending on the solvent composition has been shown. Weak CH...O hydrogen bonds have been postulated for explanation of the spectra.     

Plastic Versus Glass Support for an Immunoassay on Metal-Coated Surfaces in Optically Dense Samples Utilizing Directional Surface Plasmon-Coupled Emission

We compared plastic (polycarbonate) and high-quality glass support materials for gold-coated slides, when performing a model immunoassay against rabbit IgG using fluorescently labeled (AlexaFluor-647) anti-rabbit IgG, and detecting surface plasmon-coupled emission (SPCE) signals. Both, glass and plastic slides were simultaneously coated with a 48-nm layer of gold and protected with a 10-nm layer of silica. The maximum SPCE signal of AlexaFluor-647 was only two- to three-fold smaller on plastic slides than on glass slides. A small difference in the SPCE angles on glass (θ _F = 55°) and plastic (θ _F = 52.5°) slides was observed and can be explained with a slightly smaller refractive index of the plastic. We have not found any difference in the angle distribution (sharpness of the fluorescence signal at optimal SPCE angle) for the plastic slide compared to the glass slide. The kinetics of binding was monitored on the plastic slide as well as on the glass slide. Optically dense samples, a 4% red blood cell suspension and a 15% hemoglobin solution, are causing a reduction in the immunoassay SPCE signal by approximately 15% and three times, respectively, and the percentage of the reduction is the same for plastic and for glass slides. We believe that plastic substrates can be readily used in any SPCE assay, with only marginally lower total signal compared to high-quality glass slides.     

Thiophen-sulfoxide

The synthesis of several 5-methylsulfinyl-2-thiophenaldehyde derivatives is described.

     

A deprotonated intermediate in the amide methanolysis reaction of an N4O-ligated mononuclear zinc complex

Treatment of [(ppbpa)Zn](ClO4)2 (1(ClO4)2, ppbpa = N-((6-(pivaloylamido)-2-pyridyl)methyl)-N,N-bis((2-pyridyl)methyl)amine) with 1 equiv of Me(4)NOH.5H(2)O in methanol-acetonitrile solution results within minutes in the stoichiometric formation of a complex having a deprotonated amide, [(ppbpa-)Zn]ClO4 (3). Complex 3 has been characterized by 1H and 13C NMR, FTIR, and elemental analysis. Notably, upfield shifts of specific 1H NMR resonances of the amide-appended pyridyl moiety in 3, versus those found for 1(ClO4)2, indicate delocalization of the anionic charge within the amide-appended pyridyl donor of this complex. Heating of analytically pure 3 in methanol-acetonitrile results in amide alcoholysis. Overall, this alcoholysis reaction is second-order, with a first-order dependence on both 3 and methanol. Analysis of the rate of decay of 3 as a function of temperature yielded activation parameters consistent with an intramolecular amide cleavage process (DeltaH++ = 15.0(3) kcal/mol, DeltaS++ = -33(1) eu). A possible reaction mechanism for amide alcoholysis is presented which involves reaction of the deprotonated amide intermediate 3 with methanol to produce a Lewis activated-type structure from which amide cleavage may be initiated. Additional support for this mechanistic pathway has been obtained through examination of the analogous ethanolysis reaction and via evaluation of the effect of varying steric hindrance near the amide carbonyl unit.     

Structure of 6,13-bis(<Emphasis Type="Italic">N</Emphasis>, <Emphasis Type="Italic">N</Emphasis>-dimethylcarbamoyl) thioquinanthrene

The crystal structure of 6,13-bis-(N,N-dimethylcarbamoyl)thioquinanthrene 3 has been determined as monoclinic, with space group P2(1)/c with lattice parameters a = 10.044(2) Å, b = 21.385(4) Å, c = 10.889(3) Å, = 102.92(3)°, Z = 4 and D_calc = 1.342 Mg/m³. The middle 1,4-dithiin ring in the title compound 3, C₂₄H₂₀N₄O₂S₂ is in a boat conformation with the dihedral angle between the planes of the aromatic rings 132.45(8)°.     

Three-step synthesis of chiral and sterically hindered amino alcohols based on cyclic enol phosphates

The new synthesis of chiral and sterically hindered 1,2-amino alcohols derivatives of 2-methyl-indane and 1,2,3,4-tethrahydrophenanthrene based on cyclic enol phosphates were investigated. The desired products were obtained using three step procedure: oxidation of accessible enol phosphates, transformation α-hydroxy ketones into corresponding oximes and finally reduction of the last one to 1,2-amino alcohols. The optimal conditions of all stages to obtain products with high enantioselectivity or diastereomeric ratio were found and elaborated. The structures and absolute configurations of (3R)-2,3-dihydro-3-hydroxy-1H-phenanthren-4-one and corresponding oxime were confirmed by X-ray analysis.     

Application of thermal imaging to assess the superficial skin temperature distribution after local cryotherapy and ultrasound

Thermal imaging is a safe, noninvasive, and quite low-cost technique that allows for the rapid and noninvasive recording of thermal radiation emitted by the human body. In recent years, it is increasingly used for physiotherapy monitoring. The main goal of the study was to compare the influence of two various treatments applied in two various orders, namely local cryotherapy (CRYO) and ultrasound therapy (US). The impact of combined therapies, applied in two various orders, was studied in terms of changes of the superficial temperature distribution on the front right thigh surface. The response to the therapy depending the treated persons’ gender, along with a consensual reaction, was examined. The research material consisted of 30 healthy volunteers, 19–23-year old students, aged 19.93 (± 1.42). All treatments were performed at weekly intervals in the following order: in the first week, CRYO immediately followed by US, and in the second week, ultrasound immediately followed by local cryotherapy. All treatments were performed on the right quadriceps. The combined sequence of local cryotherapy and ultrasound therapy caused temperature decrease in the treated area regardless of their performance order. The temperature decrease considerably depends on the sequence of the applied treatments, and it was more significant after the ultrasound–cryotherapy sequence. Moreover, these changes also lasted longer. Statistically significant influence of the subjects’ gender was observed in case of consensual reaction.