Surface-deposited acid/base on glass microfibers in formation of (3-aminopropyl)triethoxysilane-[2-(3,4-epoxycyclohexyl)ethyl]heptaisobutyloctasilsesquioxane bioverlay

Silanization of macroporous glass microfiber filters with (3-aminopropyl)triethoxysilane (APTES) and subsequent binding of [2-(3,4-epoxycyclohexyl)ethyl]heptaisobutyloctasilsesquioxane (E-POSS) to the amine-terminated surface of microfibers was studied. Prior to the silanization, minute quantities of concentrated aqueous solutions of hydrochloric acid or ammonia were adsorbed in the filters while attachment of E-POSS molecules to APTES overlay was not specially catalyzed. Analysis of DRIFT, XPS, and 13C CP/MAS NMR spectra has shown that the formation of APTES overlay is affected differently by the surface-deposited acid or base. It was proved by XPS that microfibers with the adsorbed acid take up higher amounts of covalently attached APTES by 42% and, subsequently, of E-POSS by 65% than microfibers with the adsorbed ammonia. The molecular mechanics model calculations, which were made using silica as a template, have shown that approximately two-layered APTES coating can be built on the model surface if complete hydrolysis of ethoxy groups and vertical condensation of APTES species are assumed.     

Order-topological separable complete modular ortholattices admit order continuous faithful valuations

We prove that on every separable complete atomic modular ortholattice (i.e.order topological) there exists an order continuous faithful valuation. We also give a construction of the existing order continuous faithful valuation. For separable atomic modular ortholattices we give a necessary and sufficient condition to admit an order continuous faithful valuation and we show that it is equivalent with the condition to have a modular MacNeille completion. We improve one statement on complete metric lattices from Birkhoff's Lattice Theory.

     

The influence of enhanced UV-B radiation on Batrachium trichophyllum and Potamogeton alpinus -- aquatic macrophytes with amphibious character

The responses of two amphibious species, Batrachium trichophyllum and Potamogeton alpinus to different UV-B environments were studied. Plant material from natural environments, as well as from outdoor treatments was examined. In long-term outdoor experiments plants were grown under three different levels of UV-B radiation: reduced and ambient UV-B levels, and a UV-B level simulating 17% ozone depletion. The following parameters were monitored: contents of total methanol soluble UV-absorbing compounds and chlorophyll a, terminal electron transport system (ETS) activity and optimal and effective quantum yield of photosystem II. No effect of the different UV-B levels on the measured parameters was observed. The amount of UV-B absorbing compounds seems to be saturated, since no differences were observed between treatments and no increase was found in peak season, when natural UV-B levels were the highest. Physiological measurements revealed no harmful effects; neither on potential and actual photochemical efficiency, nor on terminal ETS activity. The contents of UV-B absorbing compounds were examined also in plant material sampled in low and high altitude environments during the growth season. Both species exhibited no seasonal dynamics of production of UV-absorbing compounds. The contents were variable and showed no significant differences between high and low altitude populations.     

Pastings of MV-Effect Algebras

We give a method of constructing a lattice effect algebra E with given family of blocks. The given MV-effect algebras are pasted along some common sub-MV-effect algebras in a such manner that there exists an ((o)-continuous) state on the pasting E.     

A systematic study on the extractability of arsenic species from algal certified reference material IAEA-140/TM (Fucus sp., Sea Plant Homogenate) using methanol/water extractant mixtures

Using methanol/water mixtures (from pure water to pure methanol), with different desorption and solubility parameters, and varying extractant volume to algal mass (V/m) ratios, the extractability of arsenic species from CRM IAEA-140/TM was investigated. A linear sorption isotherm-based model was developed to process the data obtained with variable volume extraction, allowing the unambiguous deduction of the maximal extractable species concentrations under the specific extraction conditions, even for more stable species.The maximal extractable arsenic fraction ranged from 41 to 68% of the total arsenic concentration in CRM IAEA-140/TM, depending on the extractant composition, with pure methanol giving the lowest extraction yield and pure water giving erratic extractability (probably due to bad wettability). The main arsenic species quantified in the methanol/water extracts were arsenosugars, with arsenosugars 1 (glycerol arsenosugar), 3 (sulfonate arsenosugar) and 4 (sulfate arsenosugar) making up ca. 90% of the maximal extractable arsenic. The rest accounts for DMA (dimethylarsinate), arsenosugar 2 (phosphate arsenosugar) and As(V). There is no clear extraction pattern emerging from the data although it may be seen that extraction of more polar species (e.g. arsenosugar 1) is favoured in pure methanol and less polar more ionic species (e.g. arsenosugar 2 and As(V)) in methanol extractants with a higher water percentage.The precise and highly accurate data may be used for quality control purposes under strictly followed extraction conditions since the extraction is operationally defined. Additionally, the variable volume extraction methodology presented may be applied to other elemental species in other matrices using other extractants. Although this approach does not maximise the absolute extractability but only that which is extractant-specific, experimentators are forewarned that in most cases only a fingerprint of the extractant-specific species is produced unless a quantitative extraction of all species is obtained.     

Poly(ethylene glycol) (PEG) enhances dynamic surface activity of a bovine lipid extract surfactant (BLES)

Shortage or malfunction of pulmonary surfactant in alveolar space leads to a critical condition termed respiratory distress syndrome (RDS). Surfactant replacement therapy, the major method to treat RDS, is an expensive treatment. In this paper, the effect of poly(ethylene glycol) (PEG) to improve dynamic surface activity of a bovine lipid extract surfactant (BLES) was studied by axisymmetric drop shape analysis (ADSA) and a captive bubble method. The activity of BLES+PEG mixtures was compared to that of a natural surfactant containing surfactant proteins A and D. When PEG was added into BLES mixtures, the surface tension hysteresis of BLES films was minimized when the films were compressed by more than 50%. PEG also helps to quickly restore surfactant films after film collapse. Thus, as far as surface tension effects go, the findings suggest that PEG might be used as a substitute for surfactant-associated protein SP-A in therapeutic surfactant products, and might also be used to reduce the amount of BLES required in clinical applications.     

5βH,6αH,7αH,10αCH3-eudesman-6,12-olides: A novel stereochemical group of natural sesquiterpene lactones. Stereostructure of isosilerolide

A new stereochemical group of eudesmanolides - 5βH,6αH,7αH,10αCH₃-eudesman-6,12-olides - was identified mainly on the basis of proton NMR spectroscopy and checked by X-ray analysis