Quasi-asymptotic contractions,set-valued dynamic systems,uniqueness of endpoints and generalized pseudodistances in uniform spaces

For set-valued dynamic systems in uniform spaces we introduce the concept of quasi-asymptotic contractions with respect to some generalized pseudodistances, describe a method which we use to establish general conditions guaranteeing the existence and uniqueness of endpoints (stationary points) of these contractions and exhibit conditions such that for each starting point each generalized sequence of iterations (in particular, each dynamic process) converges and the limit is an endpoint. The definition, result, ideas and techniques are new for set-valued dynamic systems in uniform, locally convex and metric spaces and even for single-valued maps.     

Application of very small force measurements in monitoring the response of sunflower to weak blue light

A diaheliotropic response of sunflower, Helianthus annuus, following a short pulse of low intensity blue light to a small area of leaf surface was examined with the application of the very low-force-measurements technique (the order of magnitude of 10(-5) N). One leaf from a pair was illuminated with a low intensity blue-light-pulse and the force was recorded, generated by the stem of the plant tending to bend. A very low phototropic effect in response to blue light alone was observed which could be considerably enhanced by the application of background illumination with red light. Microelectrode measurements of the membrane potential of the mesophyll cells of the sunflower leaf showed hyperpolarization in response to a blue light pulse, observed very clearly under application of the red light background illumination. The hyperpolarization of the membrane potential was accompanied by acidification of extracellular compartments as monitored with a miniature pH-sensitive electrode, placed in the epidermis of the stem. The relatively short lag period between the hyperpolarization of the membrane potential and the decrease in pH suggests that the hyperpolarization is a direct effect of the blue light-induced proton extrusion. The acidification correlates with the light response, which suggests that acidification-induced stem wall loosening is responsible for the blue light-induced bending. The examined mechanisms are discussed in terms of sun tracking by a sunflower.     

Pressurized liquid extraction of coumarins from fruits of Heracleum leskowii with application of solvents with different polarity under increasing temperature

Coumarins are nowadays an important group of organic compounds from natural sources that are useful in a number of fields. Because they possess different pharmacological properties, finding the proper extraction conditions for their separation from plant matrices is a very important step. In this report Pressurized Liquid Extraction (PLE) under different temperature conditions and with different types of extraction solvents were tested. As a matrix, fruits of Heracleum leskowii have been used. A simple reverse phase high-performance liquid chromatographic method (RP-HPLC) coupled with a photodiode array detector (DAD) has been developed for separation and quantitative analysis of the main coumarins. Umbelliferone, xanthotoxin, angelicin, isopimpinellin, bergapten, imperatorin and isoimperatorin were investigated. Bergapten and imperatorin were dominant in almost all extracts in the range of 9.92 ± 0.02-20.93 ± 0.06 and 12.19 ± 0.98-19.07 ± 0.03 mg/100 g, respectively. Dichloromethane and methanol were chosen as the most proper suitable solvents for extraction of coumarins. By increasing the temperature the amount of extracted coumarins increases in petroleum ether and dichloromethane extracts.     

Application of Internal Standard for Micro Extraction– Spectrophotometric Determination of Bismuth in Pharmaceutical Formulations

 A micro extraction – spectrophotometric procedure is developed for the determination of bismuth in pharmaceutical formulations. The procedure is based on the extraction of tetraiodobismuthate(III) ion paired with benzyltributylammonium cation into chloroform. The application of Nile Blue as internal standard (IS) enabled good analytical performance for micro-scale analysis. The ratio between the absorbances measured at 491 nm (bismuth complex) and at 632 nm (IS) was taken as the analytical signal. The procedure was carried out in Eppendorf tubes, lowering significantly the use of reagents and the volume of organic solvent. In the calibration range up to 60 mgċl⁻¹, the linear regression coefficient was 0.9999, the CV for 15 mgċl⁻¹ and for 50 mgċl⁻¹ Bi were 1.6% and 0.7% respectively. The results obtained in the analysis of pharmaceutical formulations were in good agreement with the results of EDTA titration method. Received November 25, 1999. Revision February 14, 2000.     

Analytical Assessment of Bioelements in Various Types of Black Teas from Different Geographical Origins in View of Chemometric Approach

A comprehensive approach to the mineral composition of black teas of different origins was studied using the Flame Atomic Absorption Spectrometry (FAAS) method, supported by chemometric tools including Principal Component Analysis PCA) and Classification and Regression Trees (CART). Significant differences between the teas from seven countries (Japan, Nepal, Kenya, Iran, Sri Lanka, India, and China) were shown. K was the main element determined in all teas, with an average concentration of 11,649 mg/kg, followed by Ca, Mg and Mn. In general, regarding all investigated black teas, the element content was ranked in the following order: K > Ca > Mg > Mn > Fe > Na > Zn > Cu. The applied chemometric methods allowed us to recognize black tea clusters based on their mineral composition and place of cultivation, and allowed us to find correlations between particular elements in black teas. The performed analyses revealed interesting correlations between the concentration of various elements in black teas: K was negatively correlated with Na, Fe, Mn and Cu; K was positively correlated with the content of Ca and Mg. Significant positive correlations between Mn and Fe and Mn and Zn in the studied black tea samples were also revealed. It was shown that mineral composition may be a significant factor regarding the origin of the black tea, not only considering the country, but also the region or province.     

Three‐Dimensional Information on the Phase Domain Structure of Thin Films of Polymer Blends Revealed by Secondary Ion Mass Spectrometry

We describe the technique of dynamic secondary ion mass spectrometry developed to determine three‐dimensional phase domain structures of films of polymer blends. The polymers are composed of light elements or are labeled with deuterium or heavy elements. The applicability of this method to various polymer blends forming thin and ultrathin films with flat and undulated air/film interface is discussed.     

Use of Two-Dimensional TLC to Identify Phenolic Acids in the Foliage and Fruit of Peucedanum tauricum Bieb.

JPC – Journal of Planar Chromatography – Modern TLC - Two-dimensional planar chromatography (2D TLC) on cellulose layers, solid phase extraction (SPE), and reversed-phase...     

Random iterations, fixed points and invariant CRF-horospheres in complex Banach spaces

For holomorphic noncontractive maps on (not necessarily bounded) domains in complex Banach spaces, we establish the conditions guaranteeing locally uniform convergence of random iterations and study the existence of fixed points and boundary behaviour of iterations. In particular, we show that the problem, concerning the existence of the horospheres determined by Carathéodory-Reiffen-Finsler pseudometrics defined on unbounded domains, has the solution and we prove new results of type of Julia's lemma and Wolff's theorem.     

On the spherical and zonal spherical functions on a compact quantum group

Invariance properties of the functions satisfying an integral spherical equation on a compact quantum group are discussed. It is shown that spherical and zonal spherical functions are conncected with the spherical representation of a compact quantum group.Supported by Polish Scientific Grant RPI10.