Effect of interferents present in the internal solution or in the conducting polymer transducer on the responses of ion-selective electrodes

The effect of interferents present on the opposite side of the Pb²⁺-selective membrane has been studied for both internal solution and all-solid-state sensors with a conducting polymer (CP) transducer. For interferents with moderate selectivity coefficients (sodium cations) present in the internal solution or in the CP transducer phase, super-Nernstian responses were obtained. For sensors containing strongly discriminated interferents (lithium ions), however, responses typical of conventional electrodes are observed, despite the low activity of primary ions on the opposite side of the membrane. This effect is attributed to hindered incorporation of interfering ions into the membrane, which also impairs the long term stability of the potential. Because of the relatively small absolute amounts of interferents in the transducer of all-solid-state sensors, their exchange for primary ions occurs quickly. Thus, transformation of the sensor to one with a micromolar detection limit and high potential stability is observed.      

Jacobson radical non-nil algebras of Gel’fand-Kirillov dimension 2

For an arbitrary countable field, we construct an associative algebra that is graded, generated by finitely many degree-1 elements, is Jacobson radical, is not nil, is prime, is not PI, and has Gel’fand-Kirillov dimension two. This refutes a conjecture incorrectly attributed to Goodearl.     

Extended Centres of Finitely Generated Prime Algebras

Let K be a field and let A be a finitely generated prime K-algebra. We generalize a result of Smith and Zhang, showing that if A is not PI and does not have a locally nilpotent ideal, then the extended centre of A has transcendence degree at most GKdim(A) ?2 over K. As a consequence, we are able to show that if A is a prime K-algebra of quadratic growth, then either the extended centre is algebraic over K or A is PI. Finally, we give an example of a finitely generated non-PI prime K-algebra of GK dimension 2 with a locally nilpotent ideal such that the extended centre has infinite transcendence degree over K.     

Histochemical and Phytochemical Analysis of Lamium album subsp. album L. Corolla: Essential Oil,Triterpenes, and Iridoids

The aim of this study was to conduct a histochemical analysis to localize lipids, terpenes, essential oil, and iridoids in the trichomes of the L. album subsp. album corolla. Morphometric examinations of individual trichome types were performed. Light and scanning electron microscopy techniques were used to show the micromorphology and localization of lipophilic compounds and iridoids in secretory trichomes with the use of histochemical tests. Additionally, the content of essential oil and its components were determined using gas chromatography-mass spectrometry (GC-MS). Qualitative analyses of triterpenes carried out using high-performance thin-layer chromatography (HPTLC) coupled with densitometric detection, and the iridoid content expressed as aucubin was examined with spectrophotometric techniques. We showed the presence of iridoids and different lipophilic compounds in papillae and glandular and non-glandular trichomes. On average, the flowers of L. album subsp. album yielded 0.04 mL/kg of essential oil, which was dominated by aldehydes, sesquiterpenes, and alkanes. The extract of the L. album subsp. album corolla contained 1.5 × 10⁻³ ± 4.3 × 10⁻⁴ mg/mL of iridoid aucubin and three triterpenes: oleanolic acid, β-amyrin, and β-amyrin acetate. Aucubin and β-amyrin acetate were detected for the first time. We suggest the use of L. album subsp. album flowers as supplements in human nutrition.     

Effect of Inoculated Lactic Acid Fermentation on the Fermentable Saccharides and Polyols,Polyphenols and Antioxidant Activity Changes in Wheat Sourdough

Inoculation of sourdough allows the fermentation medium to be dominated by desired microorganisms, which enables determining the kinetics of the conversion of chemical compounds by individual microorganisms. This knowledge may allow the design of functional food products with health features dedicated to consumers with special needs. The aim of the study was to assess the dynamics of transformations of fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) compounds from wheat flour as well as their antioxidant activity during inoculated and spontaneous sourdough fermentation. The FODMAP content in grain products was determined by the fructan content with negligible amounts of sugars and polyols. To produce a low-FODMAP cereal product, the fermentation time is essential. The 72 h fermentation time of L. plantarum-inoculated sourdough reduced the FODMAP content by 91%. The sourdough fermentation time of at least 72 h also positively influenced the content of polyphenols and antioxidant activity, regardless of the type of fermentation. The inoculation of both L. plantarum and L. casei contributed to a similar degree to the reduction in FODMAP in sourdough compared to spontaneous fermentation.     

Intermolecular Interactions in Crystalline Hydroxychloroquine Sulfate in Comparison with Those in Selected Antimalarial Drugs

Abstract The crystal structure of hydroxychloroquine sulfate (OHClQ) was determined in order to compare its conformation and intermolecular interactions to those in the crystalline chloroquine phosphate (ClQP) and quinine salicylate (QSal) monohydrate. The crystals of OHClQ are monoclinic with the space group P2₁/c and unit-cell dimensions: a = 10.4966(1) ?, b = 8.8056(1) ?, c = 21.8603(3) ?, β = 101.074(1)°. The quinoline antimalarial drugs may interact with their putative receptors by formation of characteristic hydrogen-bonded rings. The protonated nitrogen atoms and/or hydroxyl groups of the drug cation are proton donors, while the oxygen atoms of anions are proton acceptors. Water molecules may intermediate in these interactions. Graphical Abstract Hydroxychloroquine sulfate is a drug used in the treatment of malaria and rheumatic diseases. The X-ray structure analysis shows an important role of intermolecular hydrogen bonds in the crystal architecture. Comparison with chloroquine phosphate and quinine salicylate indicates that the organization of the drug cations is determined by the anions.      

Cyclopropanation of Terminal Alkenes through Sequential Atom‐Transfer Radical Addition/1,3‐Elimination

An operationally simple method to affect an atom‐transfer radical addition of commercially available ICH₂Bpin to terminal alkenes has been developed. The intermediate iodide can be transformed in a one‐pot process into the corresponding cyclopropane upon treatment with a fluoride source. This method is highly selective for the cyclopropanation of unactivated terminal alkenes over non‐terminal alkenes and electron‐deficient alkenes. Due to the mildness of the procedure, a wide range of functional groups such as esters, amides, alcohols, ketones, and vinylic cyclopropanes are well tolerated.     

Synthesis and theoretical characterization of some new 4‐substituted‐1,3‐diphenyl‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazoles with potential pharmacological activity

Synthesis of some new triazoles fused to triazoles 5a–c or thiadiazoles 6a–c and the thiol‐thione tautomeric equilibrium study of the title compounds are reported. The “rule of five” and complementary criteria of pharmacokinetic properties were determined to predict whether these compounds are orally bioavailable. Semiempirical parameterizations have been critically benchmarked for the thiol‐thione tautomeric equilibrium against the DFT calculations. It was shown that unlike the AM1 and PM3 Hamiltonians, which erroneously predict higher stability of the thiol tautomer, the newly developed RM1 Hamiltonian, on the other hand, predicts energetics of this equilibrium in excellent agreement with the DFT results. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:713–718, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20499     

A quantitative thermal analysis of cyclists’ thermo-active base layers

It is well known that clothes used in sporting activity are a barrier for heat exchange between the environment and athlete, which should help in thermoregulation improvement. However, it is difficult to evaluate which top is best for each athlete according to the characteristics of the sport. Researchers have tried to measure the athlete’s temperature distribution during exercise at the base layers of tops with different approaches. The aim of this case study was to investigate the use of thermography for thermo-active base layer evaluation. Six new base layers were measured on one cyclist volunteer during a progressive training on a cycloergometer. As a control condition, the skin temperature of the same volunteer was registered without any layer with the same training. A training protocol was selected approximate to cycling race, which started from the warm-up stage, next the progressive effort until the race finished and at the end “cool-down” stage was over. In order to show which layer provided the strongest and weakest barrier for heat exchange in comparison with environment, the temperature parameters were taken into consideration. The most important parameter in the studies was the temperature difference between the body and the layers, which was changing during the test time. The studies showed a correlation between the ergometer power parameter and the body temperature changes, which has a strong and significant value. Moreover, the mass of every layer was checked before and after the training to evaluate the mass of the sweat exuded during the test. From this data, the layer mass difference parameter was calculated and taken into consideration as a parameter, which may correspond with the mean heart rate value from each training. A high and positive correlation coefficient was obtained between the average heart rate and the mass difference for the base layers. Thermal analysis seems to have a new potential application in the objective assessment of sports clothing and may help in choosing the proper clothes, which could support heat transfer during exercising and protect the body from overheating.

     

Subdirectly irreducible medial quandles

We describe all subdirectly irreducible medial quandles. We show that they fall within one of four disjoint classes. In particular, in the finite case they are either connected (and therefore Alexander quandles) or reductive. Moreover, we provide a representation of all non-connected subdirectly irreducible medial quandles.