Colossal electroresistance and colossal magnetoresistive step in paramagnetic insulating phase of single crystalline bilayered manganite(La0.4_{0.4}Pr0.6_{0.6})1.2_{1.2}Sr1.8_{1.8}Mn2_{2}O7_{7}

We report a significant decrease in the low-temperature resistance induced by the application of an electric current on the $ab$-plane in the paramagnetic insulating (PMI) state of (La$_{0.4}$Pr$_{0.6}$)$_{1.2}$Sr$_{1.8}$Mn$_{2}$O$_{7}$. A colossal electroresistance effect attaining -95% is observed at lower temperatures. A colossal magnetoresistive step appears near 5T at low temperatures below 10K, accompanied by an ultrasharp width of the insulator-metal transition. Injection of higher currents to the crystal causes a disappearance of the steplike transition. These findings have a close relationship with the presence of the short-range charge-ordered clusters pinned within the PMI matrix of the crystal studied.Comment: 4 pages 3 figure

Steplike Lattice Deformation of Single Crystalline (La0.4_{0.4}Pr0.6_{0.6})1.2_{1.2}Sr1.8_{1.8}Mn2_{2}O7_{7} Bilayered Manganite

We report a steplike lattice transformation of single crystalline (La$_{0.4}$Pr$_{0.6}$)$_{1.2}$Sr$_{1.8}$Mn$_{2}$O$_{7}$bilayered manganite accompanied by both magnetization and magnetoresistive jumps, and examine the ultrasharp nature of the field-induced first-order transition from a paramagnetic insulator to a ferromagnetic metal phase accompanied by a huge decrease in resistance. Our findings support that the abrupt magnetostriction is closely related to an orbital frustration existing in the inhomogeneous paramagnetic insulating phase rather than a martensitic scenario between competing two phases.Comment: 5 pages,4figures, v4: figures are changed, in press in Phys.Rev.Let

Regio-selective substitution at the 1,3- and 6,8-positions of pyrene for the construction of small dipolar molecules

© 2015 American Chemical Society. This article presents a novel asymmetrical functionalization strategy for the construction of dipolar molecules via efficient regioselective functionalization along the Z-axis of pyrene at both the 1,3- and 6,8-positions. Three asymmetrical ly substituted 1,3-diphenyl-6,8-R-disubsituted pyrenes were fully characterized by X-ray crystallography, photophysical properties, electrochemistry, and density functional theory calculations

Toward robust and predictive geodynamic modeling : the way forward in frictional plasticity

Strain localization is a fundamental characteristic of plate tectonics. The resulting deformation structures shape the margins of continents and the internal structure of tectonic plates. To model the occurrence of faulting, geodynamic models generally rely on frictional plasticity. Frictional plasticity is normally embedded in visco‐plastic (V‐P) or visco‐elasto‐plastic (V‐E‐P) rheologies. This poses some fundamental issues, such as the difficulty, or often inability, to obtain a converged equilibrium state and a severe grid sensitivity. Here, we study shear banding at crustal‐scale using a visco‐elasto‐viscoplastic (V‐E‐VP) model. We show that this rheology allows to accurately satisfy equilibrium, leads to shear band patterns that converge upon mesh refinement, and preserves characteristic shear band angles. Moreover, a comparison with analytic models and laboratory data reveals that V‐E‐VP rheology captures first‐order characteristics of frictional plasticity. V‐E‐VP models thus overcomes limitations of V‐P and V‐E‐P models and appears as an attractive alternative for geodynamic modeling

Synthesis and evaluation of a novel ionophore based on a thiacalix[4]arene derivative bearing imidazole units

O-Alkylation of the flexible thiacalix[4]arene 1 with 2-chloromethyl-1-methyl-1H-imidazole 2 in the presence of Na₂CO₃ or K₂CO₃ afforded mono-O-alkylation product 3 in 29–51% yield, along with recovery of the starting compound. In contrast, the same reaction in the presence of Cs₂CO₃ gave only one pure stereoisomer, namely 1,3-alternate-4; other possible isomers were not observed. Alkali metal salts such as Na₂CO₃ and Cs₂CO₃ can play an important role in the conformer distribution via a template effect. The conformations of the receptors, mono-O-alkylation product 3 and that of 1,3-alternate-4, have been confirmed by X-ray crystallography. Furthermore, the complexation properties of the receptor 1,3-alternate-4 toward selected alkali/transition metal cations are reported. The two-phase solvent extraction data indicated that 1,3-alternate-4 exhibited a stronger extraction efficiency for transition metals over alkali metals. The dichromate anion extraction ability of 1,3-alternate-4 showed that it could serve as an efficient extractor of HCr₂O₇⁻/Cr₂O₇²⁻ anions at low pH

Development and characterization of osteogenic cell sheets in an in vivo model

[Excerpt] Despite some successes in the tissue engineering field its evolution seems to be tampered by limitations such as cell sourcing and the lack of adequate scaffolds to support cell growth and differentiation. The use of stem cells combined with cell sheet engineering technology seems a promising way to overcome these limitations. In this work bone marrow cells were flushed from 3 weeks old Wistar rat femurs and cultured in basal DMEM medium until subconfluence. Cells were then transferred to thermo-responsive dishes (3 x10⁵ cells/dish) and cultured for 3 weeks in osteogenic medium. [...]info:eu-repo/semantics/publishedVersio

Intraspecific differences in seed dispersal caused by differences in social rank and mediated by food availability

We use individual-based information on the behavior of wild female Japanese macaques in two consecutive years with different food availability (nut-rich vs. nut-poor) to test effects of dominance rank and nut fruiting on seed dispersal parameters. We predicted that social rank would affect dispersal (1) quantity, (2) quality, (3) species richness, and (4) percentage of berries in the diet in the nut-poor year, while these differences would disappear in the nut-rich year. We found seeds of nine fleshy-fruited plant species in the feces of the monkeys. The frequency of seed occurrence for two plant species (Viburnum dilatatum and Rosa multiflora) showed an interaction between dominance ranks and years; in the nut-poor year V. dilatatum seeds were more abundant among dominant females and R. multiflora among subordinates, while such inter-rank differences disappeared in the nut-rich year. Similarly, the intact ratio of V. dilatatum seeds was lower for dominants in the nut-poor year, while inter-rank variations disappeared in the nut-rich year. Finally, percentage of berries in diet and seed richness showed no inter-annual nor inter-rank variations. Our study highlights that differences in individuals’ social rank lead to within-group variation in seed dispersal services and that these differences are dependent on nut availability

Surgical anatomy of the sural nerve for peripheral nerve reconstruction research in swine

The use of peripheral nerves as donor nerves for peripheral nerve regeneration studies, which can provide a long peripheral nerve with intact physiological functions, for autologous nerve grafts was unknown in swine. This study investigated the surgical anatomy of sural nerves (nervus suralis) of cadavers and anesthetized miniature pigs. A loose-S shape incision line was made from the border of the biceps femoris muscle (musculus biceps femoris) to 2 cm above the calx in the leg of anesthetized miniature pigs. The sural nerve was found to branch from the sciatic nerve (nervus ischiadicus) under the biceps femoris muscle and run along the small saphenous vein (vena saphena parva). After being isolated and stimulated using a nerve stimulator, the sural nerve innervated no muscles and tissues in the leg. The sural nerve (14.

Lithium calix[4]arenes: structural studies and use in the ring opening polymerization of cyclic esters

We have structurally characterized a number of lithiated calix[4]arenes, where the bridge in the calix[4]arene is thia (–S–, LS H4), sulfinyl (–SO–, LSOH4), sulfonyl (–SO2–, LSO2H4), dimethyleneoxa (–CH2OCH2–, LCOCH4) or methylene (–CH2–, LH4). In the case of L4SH4, interaction with LiOtBu led to the isolation of the complex [Li8(L4S)2(THF)4]5THF (15THF), whilst similar interaction of L4SOH4 led to the isolation of [Li6(L4SOH)2(THF)2]5(THF) (2$5THF). Interestingly, the mixed sulfinyl/sulfonyl complexes [Li8(calix[4] arene(SO)(SO2) SO1.68)2)2(THF)6]8(THF) (38THF) and Li5Na(LSO/3SO2H)2(THF)5]7.5(THF) (47.5(THF) have also been characterized. Interaction of LiOtBu with LSO2H4 and LCOCH4 afforded [Li5L4SO2(OH)(THF)4]2THF (5$2THF) and [Li6(LCOC)2(HOtBu)2]0.78THF1.22hexane (60.78THF1.22hexane), respectively. In the case of LH4, reaction with LiOtBu in THF afforded a monoclinic polymorph [LH2Li2(thf)(OH2)2]3THF (73THF) of a known triclinic form of the complex, whilst reaction of the de-butylated analogue of LH4, namely de-BuLH4, afforded a polymeric chain structure {[Li5(de-BuL)(OH)(NCMe)3]2MeCN}n (82MeCN). For comparative catalytic studies, the complex [Li6(LPr)2(H2O)2]hexane (9 hexane), where LPr2H2 ¼ 1,3-di-n-propyloxycalix[4]areneH2, was also prepared. The molecular crystal structures of 1–9 are reported, and their ability to act as catalysts for the ring opening (co-)/polymerization (ROP) of the cyclic esters 3-caprolactone, d-valerolactone, and rac-lactide has been investigated. In most of the cases, complex 6 outperformed the other systems, allowing for higher conversions and/or greated polymer Mn