Structural first-order transformation in La2/3Ba1/3MnO3: ESR study

We have studied by the electron-spin resonance (ESR) and static magnetic field techniques, the La_2/3Ba_1/3MnO₃ perovskite, which was previously shown to exhibit a martensitic phase transformation in the vicinity of T_s∼200 K [Physical Review B 68, 054109 (2003)], leading to its structural phase-segregated state. Resonant absorptions reveal that in the temperature interval from 100 K to 340 K the compound represents a mixture of two ferromagnetic phases possessing different magnetizations, in varying proportions depending on the temperature, and a small amount of a paramagnetic phase. The results agree well with the previous neutron diffraction study. Applied in the ESR experiments, magnetic fields (2–6 kOe) strongly affect the magnetization curves: even magnetic field as high as 700 Oe modifies the anomaly in the phase transformation region and removes the difference between the zero-field cooled and field-cooled magnetization curves, which implies that the difference in the magnetic susceptibility of the coexisting phases is small and the magnetic domain configuration can be easily changed.     

ALE Ricci-flat K?hler metrics and deformations of quotient surface singularities

Let N₀=\mathbb C²/H{N_0={\mathbb C}^2/H} be an isolated quotient singularity with H ì U(2){H\subset U(2)} a finite subgroup. We show that for any \mathbb Q{\mathbb Q} -Gorenstein smoothings of N ₀ a nearby fiber admits ALE Ricci-flat K?hler metrics in any K?hler class. Moreover, we generalize Kronheimer’s results on hyperk?hler 4-manifolds (J Differ Geom 29(3):685–697, 1989), by giving an explicit classification of the ALE Ricci-flat K?hler surfaces. We construct ALF Ricci-flat K?hler metrics on the above non-simply connected manifolds. These provide new examples of ALF Ricci-flat K?hler 4-manifolds, with cubic volume growth and cyclic fundamental group at infinity.     

Convergence of invariant measures for singular stochastic diffusion equations

It is proved that the solutions to the singular stochastic p$p$-Laplace equation, p∈(1,2)$p\in (1,2)$ and the solutions to the stochastic fast diffusion equation with nonlinearity parameter r∈(0,1)$r\in (0,1)$ on a bounded open domain Λ⊂R^d$\Lambda \subset {\mathbb{R}}^d$ with Dirichlet boundary conditions are continuous in mean, uniformly in time, with respect to the parameters p$p$ and r$r$ respectively (in the Hilbert spaces L²(Λ)$L^2\left(\Lambda \right)$, H⁻¹(Λ)$H^{-1}\left(\Lambda \right)$ respectively). The highly singular limit case p=1$p=1$ is treated with the help of stochastic evolution variational inequalities, where P$\mathbb{P}$-a.s. convergence, uniformly in time, is established.     

Evaluation of the Antioxidant Activity of Nigella sativa L. and Allium ursinum Extracts in a Cellular Model of Doxorubicin-Induced Cardiotoxicity

Natural products black cumin—Nigella sativa (N. sativa) and wild garlic—Allium ursinum (AU) are known for their potential role in reducing cardiovascular risk factors, including antracycline chemotherapy. Therefore, this study investigates the effect of N. sativa and AU water and methanolic extracts in a cellular model of doxorubicin (doxo)-induced cardiotoxicity. The extracts were characterized using Ultraviolet-visible (UV-VIS) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, Liquid Chromatography coupled with Mass Spectrometry (LC-MS) and Gas Chromatography coupled with Mass Spectrometry (GC-MS) techniques. Antioxidant activity was evaluated on H9c2 cells. Cytosolic and mitochondrial reactive oxygen species (ROS) release was evaluated using 2′,7′-dichlorofluorescin-diacetate (DHCF-DA) and mitochondria-targeted superoxide indicator (MitoSOX red), respectively. Mitochondrial membrane depolarization was evaluated by flow cytometry. LC-MS analysis identified 12 and 10 phenolic compounds in NSS and AU extracts, respectively, with flavonols as predominant compounds. FT-IR analysis identified the presence of carbohydrates, amino acids and lipids in both plants. GC-MS identified the sulfur compounds in the AU water extract. N. sativa seeds (NSS) methanolic extract had the highest antioxidant activity reducing both intracellular and mitochondrial ROS release. All extracts (excepting AU methanolic extract) preserved H9c2 cells viability. None of the investigated plants affected the mitochondrial membrane depolarization. N. sativa and AU are important sources of bioactive compounds with increased antioxidant activities, requiring different extraction solvents to obtain the pharmacological effects.     

Tailored doxycycline delivery from MCM-41-type silica carriers

Doxycycline, an antibiotic from the tetracycline class with a broad spectrum of activity, was used to prepare drug delivery systems based on pristine and functionalized mesostructured silica supports. MCM-41-type materials with different textural, structural, and surface properties were used to assess their influence on the drug release kinetics. Small- and wide-angle XRD, FTIR spectroscopy and N₂ adsorption/desorption isotherms were used to characterize the carriers before and after doxycycline loading. The drug release experiments were performed in vitro in 0.2 M phosphate buffer solution at 37 °C, and the slowest drug release kinetics was obtained for magnesium-modified MCM-41 carrier. All drug-loaded materials exhibited good antibacterial activity against Klebsiella pneumoniae ATCC 10031 strain, similar to the drug alone.     

On the concept of code-isomorphy

LetF be a finite set of cardinality ¦F¦ =q 2,n 1 an integer and :F ⁿ×Fⁿ₀ theHamming metric. Acode isomorphism C D between two block codesC,D Fⁿ is defined as an isometry which can be extended to an isometry of the whole space Fⁿ. Any permutation S _n of the positions canonically induces a so-calledequivalence map Aut Fⁿ; any system (₁,₂,...,_n) ofn permutations of the character setF induces a so-calledconfiguration Aat Fⁿ. The group Aut Fⁿ of all isometries of Fⁿ turns out to be semidirect product of the configuration group with the symmetric group of degreen. The codeword estimating failure probability of a maximum likelihood codeword estimator for aq-nary symmetric channel does not depend on the transmitted codeword, if the automorphism group of the code acts transitively on the set of codewords. When using a systematic (n, k)-encoder, the symbol decoding failure probability does not depend on the transmitted symbol or on the time of transmission if the configuration group and the automorphism group act transitively on the set of codewords resp. on the set of thek information positions.In memoriam Giuseppe Tallini     

High-resolution MALDI imaging mass spectrometry allows localization of peptide distributions at cellular length scales in pituitary tissue sections

Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) has been used to determine peptide distributions directly from rat, mouse and human pituitary tissue sections. Since these organs are small (10²–10³ μm) the spatial resolution of IMS is a key issue in molecular imaging of pituitary tissue sections. Here we show that high-resolution IMS allows localization of neuropeptide distributions within different cell clusters of a single organ of a pituitary tissue section. The sample preparation protocol does not result in analyte redistribution and is therefore applicable to IMS experiments at cellular length scales. The stigmatic imaging mass spectrometer used in this study produces selected-ion-count images with pixel sizes of 500 nm and a resolving power of 4 μm, yielding superior spatial detail compared to images obtained in microprobe imaging experiments. Furthermore, we show that with imaging mass spectrometry a distinction can be made between different mammalian tissue sections based on differences in the amino acid sequence of neuropeptides with the same function. This example demonstrates the power of IMS for label-free molecular imaging at relevant biological length scales.