Negative thermal expansion in the Prussian Blue analog Zn3[Fe(CN)6]2: X-ray diffraction and neutron vibrational studies

The cubic Prussian Blue (PB) analog, Zn3 [Fe(CN)6]2, has been studied by X-ray powder diffraction and inelastic neutron scattering (INS). X-ray data collected at 300 and 84 K revealed negative thermal expansion (NTE) behaviour for this material. The NTE coefficient was found to be -31.1 x 10-6 K-1. The neutron vibrational spectrum for Zn3[Fe(CN)6]2.xH2O, was studied in detail. The INS spectrum showed well-defined, well-separated bands corresponding to the stretching of and deformation modes of the Fe and Zn octahedra, all below 800 cm-1.Comment: 4 pages, 3 figure

KLEIN: A New Family of Lightweight Block Ciphers

Resource-efficient cryptographic primitives become fundamental for realizing both security and efficiency in embedded systems like RFID tags and sensor nodes. Among those primitives, lightweight block cipher plays a major role as a building block for security protocols. In this paper, we describe a new family of lightweight block ciphers named KLEIN, which is designed for resource-constrained devices such as wireless sensors and RFID tags. Compared to the related proposals, KLEIN has advantage in the software performance on legacy sensor platforms, while in the same time its hardware implementation can also be compact

Tumor necrosis factor-alpha regulates the expression of inducible costimulator receptor ligand on CD34+ progenitor cells during differentiation into antigen presenting cells

The inducible costimulator receptor (ICOS) is a third member of the CD28 receptor family that regulates T cell activation and function. ICOS binds to a newly identified ligand on antigen presenting cells different from the CD152 ligands CD80 and CD86. We used soluble ICOSIg and a newly developed murine anti-human ICOS ligand (ICOSL) monoclonal antibody to further characterize the ICOSL during ontogeny of antigen presenting cells. In a previous study, we found that ICOSL is expressed on monocytes, dendritic cells, and B cells. To define when ICOSL is first expressed on myeloid antigen presenting cells, we examined ICOSL expression on CD34 cells in bone marrow. We found that CD34bright cells regardless of their myeloid commitment were ICOSL , whereas ICOSL was first expressed when CD34 expression diminished and the myeloid marker CD33 appeared

Neutron Scattering to Characterize Cu/Mg(Li) Destabilized Hydrogen Storage Materials

Cu-Li-Mg-(H,D) was studied as an example of destabilizer of the Ti-(H,D) system. A Cu-Li-Mg alloy was prepared resulting in the formation of a system with 60.5 at% of CuLi0.08Mg1.92, 23.9 at% of CuMg 2 and 15.6 at% of Cu2Mg. Titanium was added to a fraction of this mixture so that 68.2 at% (47.3 wt%) of the final mixture was Ti. The mixture was ground and kept at 200 °C/473 K for 7h under H2 or 9h under D2 at P = 34 bar. Under those conditions, neutron powder diffraction shows the formation of TiD2, as well as of the deuteride of CuLi0.08Mg1.92. Similarly inelastic neutron scattering shows that at 10 K TiH2 is present in the sample, together with the hydride of CuLi0.08Mg1.92. Interestingly, at 10 K TiH 2 is very clearly detected and at 300 K TiH2 is still clearly present as indicated by the neutron vibrational spectrum, but CuLi 0.08Mg1.92-H is not detected anymore. These results indicate that Ti(H,D)2 is possibly formed by diffusion of hydrogen from the Cu-Li-Mg-(H,D) alloys. This is an intriguing result since TiH 2 is normally synthesized from the metal at T > 400°C/673 K (and most commonly at T ∼ 700 °C/973 K). In the presence of CuLi 0.08Mg1.92, TiH2 forms at a temperature that is 300 - 400 K lower than that needed to synthesize it just from the elements

Tilted and crossing vortex chains in layered superconductors

In the presence of the Josephson vortex lattice in layered superconductors, a small c-axis magnetic field penetrates in the form of vortex chains. In general, the structure of a single chain is determined by the ratio of the London [$\lambda$] and Josephson [$\lambda_{J}$] lengths, $\alpha= \lambda/\lambda_{J}$. The chain is composed of tilted vortices at large $\alpha$'s (tilted chain) and at small $\alpha$'s it consists of a crossing array of Josephson vortices and pancake-vortex stacks (crossing chain). We study chain structures at intermediate $\alpha$'s and found two types of phase transitions. For $\alpha\lesssim 0.6$ the ground state is given by the crossing chain in a wide range of pancake separations $a\gtrsim [2-3]\lambda_J$. However, due to attractive coupling between deformed pancake stacks, the equilibrium separation can not exceed some maximum value depending on the in-plane field and $\alpha$. The first phase transition takes place with decreasing pancake-stack separation $a$ at $a=[1-2]\lambda_{J}$, and rather wide range of the ratio $\alpha$, $0.4 \lesssim \alpha\lesssim 0.65$. With decreasing $a$, the crossing chain goes through intermediate strongly-deformed configurations and smoothly transforms into a tilted chain via a second-order phase transition. Another phase transition occurs at very small densities of pancake vortices, $a\sim [20-30]\lambda_J$, and only when $\alpha$ exceeds a certain critical value $\sim 0.5$. In this case a small c-axis field penetrates in the form of kinks. However, at very small concentration of kinks, the kinked chains are replaced with strongly deformed crossing chains via a first-order phase transition. This transition is accompanied by a very large jump in the pancake density.Comment: Proceeding of the NATO ARW "Vortex dynamics in superconductors and other complex systems", Yalta, Crimea, Ukraine, 13-17 September 2004, To be published in the Journ. of Low Temp. Phys., 16 pages, 6 figure

Label-free CARS microscopy reveals similar triacylglycerol acyl chain length and saturation in myocellular lipid droplets of athletes and individuals with type 2 diabetes

Aims/hypothesis: Intramyocellular lipid (IMCL) content associates with development of insulin resistance, albeit not in insulinsensitive endurance-trained athletes (trained). Qualitative and spatial differences in muscle lipid composition may underlie this so-called athlete’s paradox. Here we studied triacylglycerol (TAG) composition of individual myocellular lipid droplets (LDs) in trained individuals and individuals with type 2 diabetes mellitus.Methods: Trained (˙V O2max 71.0 \ub1 1.6 ml O2 [kg lean body mass (LBM)]−1 min−1), normoglycaemic (fasting glucose 5.1 \ub1 0.1 mmol/l) individuals and untrained (V O2max 36.8 \ub1 1.5 ml O2 [kg LBM]−1 min−1) individuals with type 2 diabetes (fasting glucose 7.4 \ub1 0.5 mmol/l), with similar IMCL content (3.5 \ub1 0.7% vs 2.5 \ub1 0.3%, p = 0.241), but at opposite ends of the insulin sensitivity spectrum(glucose infusion rate 93.8 \ub1 6.6 vs 25.7 \ub1 5.3 μmol [kg LBM]−1 min−1 for trained individuals and those with type 2 diabetes, respectively) were included from our database in the present study. We applied in situ label-free broadbandcoherent anti-Stokes Raman scattering (CARS) microscopy to sections from skeletal muscle biopsies to measure TAG acyl chain length and saturation of myocellular LDs. This approach uniquely permits examination of individual LDs in their native environment, in a fibre-type-specific manner, taking into account LD size and subcellular location.Results: Despite a significant difference in insulin sensitivity, we observed remarkably similar acyl chain length and saturation in trained and type 2 diabetic individuals (chain length: 18.12 \ub1 0.61 vs 18.36 \ub1 0.43 number of carbons; saturation: 0.37 \ub1 0.05 vs 0.38 \ub1 0.06 number of C=C bonds). Longer acyl chains or higher saturation (lower C=C number) could be detected in subpopulations of LDs, i.e. large LDs (chain length: 18.11 \ub1 0.48 vs 18.63 \ub1 0.57 carbon number) and subsarcolemmal LDs (saturation: 0.34 \ub1 0.02 vs 0.36 \ub1 0.04 C=C number), which are more abundant in individuals with type 2 diabetes.Conclusions/interpretation: In contrast to reports of profound differences in the lipid composition of lipids extracted from skeletal muscle from trained and type 2 diabetic individuals, our in situ, LD-specific approach detected only modest differences in TAGcomposition in LD subpopulations, which were dependent on LD size and subcellular location. If, and to what extent, these modest differences can impact insulin sensitivity remains to be elucidated

Способы повышения прочности алюмосиликатной керамики на основе сухарного глинистого сырья

Disrupting the CD40-CD40L co-stimulatory pathway reduces atherosclerosis and induces a stable atherosclerotic plaque phenotype that is low in inflammation and high in fibrosis. Therefore, inhibition of the CD40-CD40L pathway is an attractive therapeutic target to reduce clinical complications of atherosclerosis. The CD40-CD40L dyad is known to interact with other co-stimulatory molecules, to activate antigen-presenting cells (APC) and to contribute to T-cell priming and B-cell isotype switching. Besides their presence on T-cells and APCs, CD40 and CD40L are also present on macrophages, endothelial cells and vascular smooth muscle cells in the plaque, where they can exert pro-atherogenic functions. Moreover, recent progress indicates the involvement of neutrophil CD40, platelet CD40L and dendritic cell CD40 in atherogenesis. Since systemic CD40-CD40L modulation compromises host defense, more targeted interventions are needed to develop superior treatment strategies for atherosclerosis. We believe that by unravelling the cell-cell CD40-CD40L interactions, inhibition of cell-type specific (signalling components of) CD40(L) that do not compromise the patient's immune system, will become possible. In this review, we highlight the cell-type specific multi-functionality of CD40-CD40L signalling in atherosclerosi