FLUORESCENCE PROPERTIES OF AN ELECTRON ACCEPTOR SUBSTITUTED BIS-PYRAZOLO-PYRIDINE DERIVATIVE: NO2-DMPP*

The fluorescence properties of 3,5-dimethyl-1,7-diphenyl-4-(4'-nitrophenyl)-bis-pyrazolo- [3,4-b;4', 3'-e]-pyridine (NO 2 -DMPP) and its parent compound 3"5-dimethyl-1,7-diphenyl-bis-pyrazolo-[3"4-b;4', 3"-e]-pyridine (BPP, without the nitrophenyl substituent) were investigated. BPP is a highly fluorescent blue emitter and the fluorescence properties, the emission wavelength, and the fluorescence quantum yield, depend only slightly on solvent. On the contrary, acceptor substituted NO2-DMPP shows dual fluorescence: A long-wavelength component experiences a red-shift with increasing solvent polarity but is efficiently quenched when the polarity exceeds that of solvents like 1,2-dichloroethane or 1-bromopropane. A weak short-wavelength component changes only slightly its position and intensity upon variation of the solvent but its yield increases strongly at low temperatures. The experimental results are discussed in the context of the results of semiempirical calculations which show that fluorescence originates from two closely lying fluorescent states which change their sequence and properties when the polarity of the solvent is varied. A twisted intramolecular charge transfer (TICT) state does most likely not contribute to the emission properties, because of its high energy. PACS numbers: 33.50.Dq, 34.70.+e *The results of this paper were initially presented a

Topics on n-ary algebras

We describe the basic properties of two n-ary algebras, the Generalized Lie Algebras (GLAs) and, particularly, the Filippov (or n-Lie) algebras (FAs), and comment on their n-ary Poisson counterparts, the Generalized Poisson (GP) and Nambu-Poisson (N-P) structures. We describe the Filippov algebra cohomology relevant for the central extensions and infinitesimal deformations of FAs. It is seen that semisimple FAs do not admit central extensions and, moreover, that they are rigid. This extends the familiar Whitehead's lemma to all $n\geq 2$ FAs, n=2 being the standard Lie algebra case. When the n-bracket of the FAs is no longer required to be fully skewsymmetric one is led to the n-Leibniz (or Loday's) algebra structure. Using that FAs are a particular case of n-Leibniz algebras, those with an anticommutative n-bracket, we study the class of n-Leibniz deformations of simple FAs that retain the skewsymmetry for the first n-1 entires of the n-Leibniz bracket.Comment: 11 page

Cohomology of Filippov algebras and an analogue of Whitehead's lemma

We show that two cohomological properties of semisimple Lie algebras also hold for Filippov (n-Lie) algebras, namely, that semisimple n-Lie algebras do not admit non-trivial central extensions and that they are rigid i.e., cannot be deformed in Gerstenhaber sense. This result is the analogue of Whitehead's Lemma for Filippov algebras. A few comments about the n-Leibniz algebras case are made at the end.Comment: plain latex, no figures, 29 page

PIP2-Binding Site in Kir Channels: Definition by Multiscale Biomolecular Simulations†

Phosphatidylinositol bisphosphate (PIP(2)) is an activator of mammalian inwardly rectifying potassium (Kir) channels. Multiscale simulations, via a sequential combination of coarse-grained and atomistic molecular dynamics, enabled exploration of the interactions of PIP(2) molecules within the inner leaflet of a lipid bilayer membrane with possible binding sites on Kir channels. Three Kir channel structures were investigated: X-ray structures of KirBac1.1 and of a Kir3.1-KirBac1.3 chimera and a homology model of Kir6.2. Coarse-grained simulations of the Kir channels in PIP(2)-containing lipid bilayers identified the PIP(2)-binding site on each channel. These models of the PIP(2)-channel complexes were refined by conversion to an atomistic representation followed by molecular dynamics simulation in a lipid bilayer. All three channels were revealed to contain a conserved binding site at the N-terminal end of the slide (M0) helix, at the interface between adjacent subunits of the channel. This binding site agrees with mutagenesis data and is in the proximity of the site occupied by a detergent molecule in the Kir chimera channel crystal. Polar contacts in the coarse-grained simulations corresponded to long-lived electrostatic and H-bonding interactions between the channel and PIP(2) in the atomistic simulations, enabling identification of key side chains

Quality of fat from oilseeds used to produce selected kinds of bread

W pracy określono stopień hydrolizy i utlenienia tłuszczów zawartych w nasionach oleistych, nasionach wyodrębnionych z pieczywa (stanowiących dodatek do tego pieczywa) oraz tłuszczów miękiszu pieczywa. Dodatkowo w tłuszczu miękiszu pieczywa określono skład kwasów tłuszczowych. Materiałem badawczym, pochodzącym z tej samej piekarni, było: 5 próbek nasion oleistych (słonecznik, soja, dynia, len, sezam) oraz 7 rodzajów pieczywa (jeden bez dodatku nasion oleistych i sześć z dodatkiem nasion oleistych). W tłuszczu, wyekstrahowanym z nasion wyjściowych i wyodrębnionych z pieczywa oraz z miękiszu pieczywa, oznaczono liczbę kwasową, nadtlenkową i anizydynową, zawartość dienów i trienów oraz skład kwasów tłuszczowych. Stwierdzono, że tłuszcz nasion oleistych (surowca) zawierał mało WKT i nadtlenków, ale dużo wtórnych produktów utlenienia. Proces wypieku pieczywa spowodował zwiększenie stopnia hydrolizy i utlenienia tłuszczu nasion, przy czym w znacznie większym stopniu tych, które zastosowano do posypania powierzchni pieczywa. Nasiona lnu ze skórki pieczywa zawierały ponad 2-krotnie więcej nadtlenków i ponad 3-krotnie więcej wtórnych produktów utlenienia niż nasiona z miękiszu. Tłuszcz miękiszu pieczywa z nasionami, w porównaniu z tłuszczem pieczywa bez dodatków, cechowała mniejsza liczba kwasowa, anizydynowa, zawartość dienów i trienów oraz w większości przypadków mniejsza liczba nadtlenkowa. Dodatek nasion oleistych korzystnie zmniejszył udział kwasów nasyconych, a zwiększył nienasyconych, w tym NNKT. Wyniki badań wskazują, że nasiona oleiste należy dodawać do ciasta, a nie posypywać nimi powierzchni pieczywa.Under this research study, determined were the degrees of hydrolysis and oxidation of the fats contained in oilseeds, in seeds isolated from the bread studied (those seeds constituted a bread additive), as well as of the fats contained in the bread crumb. In addition, determined was the composition of fatty acids in the fat from the bread crumb. The research material, originating from the same bakery, comprised: 5 samples of oilseeds (sunflower, soybean, pumpkin, linseed, and sesame) and 7 kinds of bread (one without oilseeds added and six with oilseeds added). In the fat extracted from the initial oilseeds and isolated from the bread and bread crumb, the following was determined: values of acid, peroxide, and anisidine, contents of dienes and trienes, and fatty acid composition. It was found that the fat from oilseeds (raw material) contained low amounts of free fatty acids (FFA) and peroxides, but high amounts of secondary oxidation products. The baking process caused the degrees of lipid hydrolysis and oxidation in the oilseeds to increase; and the extent of this increase was essentially higher in the case of seeds scattered over the bread’s surface. Compared to the seeds from the bread crumb, the linseeds from the bread crust contained more than a double amount of peroxides, and the content of secondary oxidation products therein was over three times higher. Compared to the fat in the bread with no additives, the fat in the bread crumb with oilseeds was characterized by a lower acid values, a lower anisidine value, lower contents of dienes and trienes, and, in the majority of cases, a lower peroxide value. The addition of oilseeds was found to beneficially decrease the content of saturated fatty acids and to increase that of unsaturated fatty acids. The research results suggest that oilseeds should be added to bread dough instead of scattering them over the bread’s surface