Effect of 13-cis violaxanthin on organization of light harvesting complex II in monomolecular layers11Paper dedicated to Professor Danuta Fra̧ckowiak on the occasion of her 75 birthday.

AbstractLutein, neoxanthin and violaxanthin are the main xanthophyll pigment constituents of the largest light-harvesting pigment–protein complex of photosystem II (LHCII). High performance liquid chromatography analysis revealed photoisomerization of LHCII-bound violaxanthin from the conformation all-trans to the conformation 13-cis and 9-cis. Maximally, the conversion of 15% of all-trans violaxanthin to a cis form could be achieved owing to the light-driven reactions. The reactions were dark-reversible. The all-trans to cis isomerization was found to be driven by blue light, absorbed by chlorophylls and carotenoids, as well as by red light, absorbed exclusively by chlorophyll pigments. This suggests that the photoisomerization is a carotenoid triplet-sensitized reaction. The monomolecular layer technique was applied to study the effect of the 13-cis conformer of violaxanthin and its de-epoxidized form, zeaxanthin, on the organization of LHCII as compared to the all-trans stereoisomers. The specific molecular areas of LHCII in the two-component system composed of protein and exogenous 13-cis violaxanthin or 13-cis zeaxanthin show overadditivity, which is an indication of the xanthophyll-induced disassembly of the aggregated forms of the protein. Such an effect was not observed in the monomolecular layers of LHCII containing all-trans conformers of violaxanthin and zeaxanthin. 77 K chlorophyll a fluorescence emission spectra recorded from the Langmuir–Blodgett (L–B) films deposited to quartz from monomolecular layers formed with LHCII and LHCII in the two-component systems with all-trans and 13-cis isomers of violaxanthin and zeaxanthin revealed opposite effects of both conformers on the aggregation of the protein. The cis isomers of both xanthophylls were found to decrease the aggregation level of LHCII and the all-trans isomers increased the aggregation level. The calculated efficiency of excitation energy transfer to chlorophyll a from violaxanthin assumed to remain in two steric conformations was analyzed on the basis of the chlorophyll a fluorescence excitation spectra and the mean orientation of violaxanthin molecules in LHCII (71° with respect to the normal to the membrane), determined recently in the linear dichroism experiments [Gruszecki et al., Biochim. Biophys. Acta 1412 (1999) 173–183]. The calculated efficiency of excitation energy transfer from the violaxanthin pool assumed to remain in conformation all-trans was found to be almost independent on the orientation angle within a variability range. In contrast the calculated efficiency of energy transfer from the form cis was found to be strongly dependent on the orientation and varied between 1.0 (at 67.48°) and 0 (at 70.89°). This is consistent with two essentially different, possible functions of the cis forms of violaxanthin: as a highly efficient excitation donor (and possibly energy transmitter between other chromophores) or purely as a LHCII structure modifier

Preceding rule induction with instance reduction methods

A new prepruning technique for rule induction is presented which applies instance reduction before rule induction. An empirical evaluation records the predictive accuracy and size of rule-sets generated from 24 datasets from the UCI Machine Learning Repository. Three instance reduction algorithms (Edited Nearest Neighbour, AllKnn and DROP5) are compared. Each one is used to reduce the size of the training set, prior to inducing a set of rules using Clark and Boswell's modification of CN2. A hybrid instance reduction algorithm (comprised of AllKnn and DROP5) is also tested. For most of the datasets, pruning the training set using ENN, AllKnn or the hybrid significantly reduces the number of rules generated by CN2, without adversely affecting the predictive performance. The hybrid achieves the highest average predictive accuracy

Preliminary studies on the possibility of prediction of quality parameters of waste produced in the process of coals enrichment

Urobek wydobywany w wyniku eksploatacji prowadzonej w kopalniach węgla kamiennego jest zbiorem różnej wielkości ziarn węgla, ziarn skały płonnej, łupków przywęglowych, pirytu, przerostów węglowo-kamiennych. W takiej postaci nie nadaje się do bezpośredniego wykorzystania przez użytkowników. Aby można go było sprzedać jako produkt handlowy musi być poddany procesom przeróbczym. Gdy parametry jakościowe urobku węglowego (dotyczy to tylko węgla energetycznego) odpowiadają potencjalnym odbiorcom wystarczy go rozsiać i w postaci sortymentów handlowych oferować użytkownikom. Najczęściej jednak, jakość urobku węglowego nie odpowiada wymaganiom jakościowym jego dalszego wykorzystania. W takich przypadkach urobek musi być poddany procesom wzbogacania polegającym na rozdziale materiału na koncentrat i odpady. Produkty odpadowe składają się z ziarn kamienia, łupków, przerostów, piasku podsadzkowego i pirytów. Mogą być one produktem handlowym, jeżeli ich parametry jakościowe spełniają wymagania konkretnych odbiorców. Wymagania te mogą być różne w zależności od kierunków zagospodarowania odpadów. Nazwa odpady jest wówczas myląca, ale taka nazwa przyjęła się w górnictwie węgla kamiennego. Bardziej odpowiednim określeniem byłby tutaj produkt pośredni lub produkt od-padowy. Aby określić przydatność takiego produktu należy przeprowadzić jego analizę mineralogiczną. Skład mineralogiczny odpadów można regulować zmieniając głębokość wzbogacania (różne gęstości rozdziału urobku na poszczególne produkty). W tym celu należy przeprowadzić analizę gęstościową podawanego do wzbogacania materiału i na jej podstawie określić korzystne dla użytkowników parametry jakościowe. Niestety procesy wzbogacania przemysłowego są niedokładne i efekty uzyskiwane w warunkach przemysłowych mogą różnić się od jakości określonej w warunkach laboratoryjnych. Przewidywanie skutków niedokładności procesów wzbogacania, na jakość produktów odpadowych, jest celem niniejszego artykułu.Material debris excavated during operations carried out in coal mines must be subjected to enrichment processes. The accuracy of the enrichment (separation of feed into individual products) depends on many factors. Factors affecting the accuracy of the separation of feed into different products make the grain of a specific density goes to products other than established on the basis of laboratory tests. This phenomenon is called dispersion of grains. The greater degree of dispersion of the particles the lower the accuracy of enrichment. In the present study probable dispersion coefficient was used to determine the accuracy of the enrichment. Prediction of the outcome of enrichment is a complex calculation issue. Assuming that the dispersion of particles has a normal distribution character it is possible to develop an appropriate mathematical model and computational computer program. In this study it was assumed that the dispersion of particles has a normal distribution character (Gaussian). It was also assumed that the waste products are isolated alternatively at densities of separation 2.0 g/cm3, 1.8 g/cm3, 1.6 g/cm3. The calculations carried out show that the accuracy of the enrichment process has an important influence on the content of individual ingredients in the waste product. The accuracy of enrichment has also an influence on yield of waste products. The higher the density of separation outcomes of waste products decrease, at low densities of separation outcomes increase

Diagnostics and monitoring of radiating sources regarding hazards for people and equipment

Pola elektromagnetyczne wykorzystywane są dzisiaj we wszystkich dziedzinach życia ludzkiego. Począwszy od kuchenek mikrofalowych w gospodarstwie domowym, poprzez przemysł, medycynę, telekomunikację, radionawigację i przemysł obronny pola elekromagnetyczne znajdują wszędzie praktyczne zastosowanie. Znane są przypadki "samoistnego" otwierania się bram, garaży, uruchamiania sygnalizacji zabezpieczającej w energetyce lub kopalniach, zakłócenia pracy systemów pokładowych samolotów, czy też wyzwalania zapalników bomb, min, itp. Wymaga to określenia zagrożeń stwarzanych przez te źródła dla ludzi, jak też aparatury dla ich ochrony.Today electromagnetic fields are used in practically all areas of human activity: in household microwave ovens, industry, medicine, telecommunications, radio navigation, the defense industry and so on. Cases of gates and garage doors opening of themselves, interference with the functioning of planes' onboard systems, setting off bombs, etc., are reported. For this reason hazards posed to both people and equipment by EMF sources should be determined in order to protect them

Analiza statystyczna sygnałów defektoskopii szyn torów kolejowych

The statistical approach to the rail testing tasks is preserved. The rail testing signals are ob-tained using the magneto-dynamical selecting method on the Lviv railway track section (Ukraine). The stationary frequency ranges for signals from typical non-faulted and faulted rails are investigated. The frequency range corresponding to defects image display is established. The basis of periodically correlated random processes (PCRP) and the scope of tasks which appear in rail testing using the PCRP methods analysis are stated. The complex of defect rail signals non-stationary correlation analysis is carried out. The possibilities of using the PCRP methods for separating the defect useful signal and localizing the defects on the early stage of their growth are shown.W pracy podano podejście statystyczne do problemu defektoskopii szyn torów kolejowych. Sygnały testowe otrzymane za pomocą metody magnetodynamicznej selekcji na odcinkach kolei Lwowskiej. Zbadano zakres częstotliwości sygnałów szyn z defektami i bez defektów w przybli-żeniu stacjonarnym. Omówiono zasady stosowania teorii okresowo skorelowanych procesów lo-sowych (OSPL) przy defektoskopii szyn kolejowych. Przeanalizowano wyniki niestacjonarnej analizy korelacyjnej sygnałów torów bez defektów. Wskazano możliwości stosowania metod statystyki OSPL dla wyodrębnienia sygnału użytecznego przy lokalizacji defektów torów we wczesnym stadium ich powstania

Surface and Structural Studies of Age-Related Changes in Dental Enamel: An Animal Model

In the animal kingdom, continuously erupting incisors provided an attractive model for studying the enamel matrix and mineral composition of teeth during development. Enamel, the hardest mineral tissue in the vertebrates, is a tissue sensitive to external conditions, reflecting various disturbances in its structure. The developing dental enamel was monitored in a series of incisor samples extending the first four weeks of postnatal life in the spiny mouse. The age-dependent changes in enamel surface morphology in the micrometre and nanometre-scale and a qualitative assessment of its mechanical features were examined by applying scanning electron microscopy (SEM) and atomic force microscopy (AFM). At the same time, structural studies using XRD and vibrational spectroscopy made it possible to assess crystallinity and carbonate content in enamel mineral composition. Finally, a model for predicting the maturation based on chemical composition and structural factors was constructed using artificial neural networks (ANNs). The research presented here can extend the existing knowledge by proposing a pattern of enamel development that could be used as a comparative material in environmental, nutritional, and pharmaceutical research