Greens functions,Hamiltonians and modular automorphisms

We demonstrate, under circumstances that allow the construction of a G(A, B; t) = w(As_t (B))G(A, B; t) = \omega (A\sigma _t (B))     

Novel VO (IV) complexes derived from a macrochelates: Synthesis,characterization, molecular modeling and in vivo insulin-mimic activity studies

For the development of extensive investigations into a potential medicinal application of vanadium coordination compounds for the oral treatment of diabetes, new mono and bimetallic VO (IV) complexes with N,N′-(2,2′-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarbonyl) bis (hydrazine-1-carbonothioyl)) dibenzamide (H₆EBT) and 2,2′-((9S,10S,11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11, 12-dicarbonyl) bis (N-phenylhydrazine-1-carboxamide) (H₆EPH) have been isolated and characterized. The FTIR and NMR spectral data revealed that H₆EBT acts as neutral tridentate and dibasic hexadentate while H₆EPH as dibasic tridentate and tetrabasic hexadentate. The electronic and ESR spectra indicated that complexes has octahedral geometry. ESR spectrum of [(VO)(H₆EBT)(SO₄)].5H₂O gives a well resolved hyperfine eight-line pattern typical spectrum for mononuclear vanadyl complexes with g˃ g_⊥ = 1.9 suggesting that the ligand donor atoms ONS are coplanar with the two chelate rings forming octahedral geometry. Also, the high parallel hyperfine splitting value, A = 0.0108, than perpendicular one (A_⊥ = 0.0087) indicated that the single d- electron is in a σ-nonbonding orbital and aiming away from the equatorial ligands. On the other hand, the EPR spectra of the binuclear [(VO)₂(H₄EBT)(SO₄)]3H₂O and [(VO)₂(H₂EPH)(H₂O)₂].10H₂O complexes gave a single broad line centered at g = 2.05 and 2.07, respectively, without resolved hyperfine structure paramagnetic triplet (S = 1) is consistent with the anomalous value of the magnetic moment value (μ_eff = 1.100 and 0.99 B.M.) supporting a binuclear nature. The TG analyses confirmed the existence of solvent molecules inside and/or outside the coordination sphere. The DFT molecular modeling of ligands and its VO (IV) complexes supported the suggested geometries. Also, all compounds were screened for in vivo insulin-mimetic activity.     

Dihydroanthracenone metabolites from the endophytic fungus Diaporthe melonis isolated from Annona squamosa

Chemical investigation of the endophytic fungus Diaporthe melonis, isolated from Annona squamosa, yielded two new dihydroanthracenone atropodiastereomers, diaporthemins A (1) and B (2), together with the known flavomannin-6,6′-di-O-methyl ether (3). The structures of the new compounds were established on the basis of extensive 1D and 2D NMR spectroscopy, as well as by high resolution mass spectrometry and by CD spectroscopy. Compounds 1–3 were tested for their antimicrobial activity against a multi-resistant clinical isolate of Staphylococcus aureus 25697, a susceptible reference strain of S. aureus ATCC 29213 and against Streptococcus pneumoniae ATCC 49619. Compound 3 strongly inhibited S. pneumonia growth with a MIC value of 2 μg/mL, and showed moderate activity against the S. aureus multi-resistant clinical isolate and susceptible reference strain (MIC 32 μg/mL), whereas 1 and 2 were not active against the tested strains.     

Human cerebrovascular contractile receptors are upregulated via a B-Raf/MEK/ERK-sensitive signaling pathway

Background  

Cerebral ischemia results in a rapid increase in contractile cerebrovascular receptors, such as the 5-hydroxytryptamine type 1B (5-HT_1B), angiotensin II type 1 (AT₁), and endothelin type B (ET_B) receptors, in the vessel walls within the ischemic region, which further impairs local blood flow and aggravates tissue damage. This receptor upregulation occurs via activation of the mitogen-activated protein kinase pathway. We therefore hypothesized an important role for B-Raf, the first signaling molecule in the pathway. To test our hypothesis, human cerebral arteries were incubated at 37°C for 48 h in the absence or presence of a B-Raf inhibitor: SB-386023 or SB-590885. Contractile properties were evaluated in a myograph and protein expression of the individual receptors and activated phosphorylated B-Raf (p-B-Raf) was evaluated immunohistochemically.     

Abundance of Invariant and Almost Invariant Pure States of -Dynamical Systems

We show that invariant states of -dynamical systems can be approximated in the weak^*-topology by invariant pure states, or almost invariant pure states, under various circumstances. Received: Received: 25 July 1996 / Accepted: 9 December 1996     

A Dynamic Mixture Model for Unsupervised Tail Estimation without Threshold Selection

Exceedances over high thresholds are often modeled by fitting a generalized Pareto distribution (GPD) on R⁺. It is difficult to select the threshold, above which the GPD assumption is enough solid and enough data is available for inference. We suggest a new dynamically weighted mixture model, where one term of the mixture is the GPD, and the other is a light-tailed density distribution. The weight function varies on R⁺ in such a way that for large values the GPD component is predominant and thus takes the role of threshold selection. The full data set is used for inference on the parameters present in the two component distributions and in the weight function. Maximum likelihood provides estimates with approximate standard deviations. Our approach has been successfully applied to simulated data and to the (previously studied) Danish fire loss data set. We compare the new dynamic mixture method to Dupuis' robust thresholding approach in peaks-over-threshold inference. We discuss robustness with respect to the choice of the light-tailed component and the form of the weight function. We present encouraging simulation results that indicate that the new approach can be useful in unsupervised tail estimation, especially in heavy tailed situations and for small percentiles.     

Effects of thermal annealing on the viscoelastic properties and morphology of bimodal hard/soft latex blends

The effects of thermal annealing on the viscoelastic properties and morphology of films prepared from bimodal latex blends containing equal weight fractions of soft and hard latex particles with controlled sizes were investigated. The thermal and viscoelastic properties of as‐dried and annealed samples were investigated with differential scanning calorimetry and dynamic mechanical analysis (DMA). Throughout the thermal annealing, the latex blend morphologies were also followed with atomic force microscopy and transmission electron microscopy (TEM). A particulate morphology, consisting of hard particles evenly dispersed in a continuous soft phase, was observed in the TEM micrographs of the as‐dried latex blends and resulted in an enhancement of the mechanical film properties at temperatures between the α relaxations of the soft and hard phases in the DMA thermograms. As soon as the thermal annealing involved temperatures higher than the glass‐transition temperature of the hard phase, the hard particles progressively lost their initial spherical shape and formed a more or less continuous phase in the latex blends. This induced coalescence of the hard particles was confirmed by the association of the experimental viscoelastic data with theoretical predictions, based on self‐consistent mechanical models, which were performed by the consideration of either a particulate or cocontinuous morphology for the bimodal latex blends. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2289–2306, 2005