Stability and index of the meet game on a lattice

We study the stability and the stability index of the meet game form defined on a meet semilattice. Given any active coalition structure, we show that the stability index relative to the equilibrium, to the beta core and to the exact core is a function of the Nakamura number, the depth of the semilattice and its gap function.     

A new conjugated addition of trialkyl phosphites and alkylidenephosphoranes to 3‐ω‐azideoacetyl coumarin synthesis of some 1,2,3,4‐triazaphospholes,triazoles, and azido‐coumarin derivatives

A new and efficient conjugate addition of trimethyl and triethyl phosphites to 3‐ω‐azidoacetylcoumarin ( 1 ) has been studied. The reaction proceeded smoothly at r.t. furnishing 1,2,3,4‐triazaphosphole coumarin derivatives 4a , 4b in ～75% yields. Linear substituted triazoles 10b , 11a were also obtained from the reactions of 1 with α‐keto ylides, acetyl‐ and benzoylmethylene triphenylphosphoranes. Contrary to these results, Wittig reaction was occurred when 1 was allowed to react with α‐alkoxycarbonylmethylene‐ and cyanomethylenetriphenylphosphoranes 7c , 7d , 7e as well as with methylidene‐ and benzylidenetriphenylphosphoranes 8b , 10a resulting in the formation of the corresponding olefins either as an intermediate 14b or as final products 11b , 11c , 12a . J. Heterocyclic Chem., (2011).     

Improved seed methods for symmetric positive definite linear equations with multiple right‐hand sides

We consider symmetric positive definite systems of linear equations with multiple right‐hand sides. The seed conjugate gradient (CG) method solves one right‐hand side with the CG method and simultaneously projects over the Krylov subspace thus developed for the other right‐hand sides. Then the next system is solved and used to seed the remaining ones. Rounding error in the CG method limits how much the seeding can improve convergence. We propose three changes to the seed CG method: only the first right‐hand side is used for seeding, this system is solved past convergence, and the roundoff error is controlled with some reorthogonalization. We will show that results are actually better with only one seeding, even in the case of related right‐hand sides. Controlling rounding error gives the potential for rapid convergence for the second and subsequent right‐hand sides. Polynomial preconditioning can help reduce storage needed for reorthogonalization. The new seed methods are applied to examples including matrices from quantum chromodynamics. Copyright © 2013 John Wiley & Sons, Ltd.     

Reactions with Hydrazonoyl Halides 611: Synthesis of 2,3-Dihydro-1,3,4-Thiadiazoles

2-[1,2-Diaza-3-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))prop-2-enylidene]-3-phenyl-5-substituted 1,3,4-thiadiazolines and 2-{[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]cyanomethylene}-3-phenyl-5-substitu- ted 1,3,4-thiadiazolines were synthesized from hydrazonoyl halides and 4-{-2-aza-2-[(methylthiothioxomethyl)amino]vinyl}-2,3-dimethyl-1-phenyl-3-pyrazoin-5-one and 2-[4-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl)-1,3-thiazol-2-yl]ethane-nitrile, respectively. All synthesize compounds were elucidated by elemental analysis, spectra, and alternative synthesis routes, whenever possible.     

Synthesis and Bioactivity of Benzothiazaphosphepines and Relevant Phosphonates as Antioxidant/Antidiabetic Agents

An efficient approach to a new series of benzothiazaphosphepines and their derived phosphonates in good yields (64–75%) was reported. The strategy relied on the reactions of the easily available 2-arylmethylene-aminobenzenethiols with different types of Wadsworth–Horner–Emmons (WHE) reagents in dimethylformamide (DMF)/lithium hydride (LiH) solution. All new compounds were bioscreened and showed, in vitro, moderate to good antioxidant and antidiabetic activities.     

Adhesive emulsion bilayers under an electric field: from unzipping to fusion

Water-in-oil emulsion drops are formed and stabilized with phospholipids which can adhere and form a bilayer. Using microfluidics, adhesive drop pairs are then trapped and submitted to an ac electric field. We observe three distinct states as a function of the adhesion energy and the electric field intensity. The pair can be either stable, though slightly deformed, or unzip and separate, or coalesce. The frontiers between the different states directly reflect vesicle detachment forces and electroporation theories. The experimental approach that we propose for probing liquid interface wetting between monolayers allows us to finely tuned the tension in the bilayer and gives access to bilayer unzipping.     

Terezine E,bioactive prenylated tryptophan analogue from an endophyte of Centaurea stoebe

Abstract

Fungal endophytes are considered promising sources of new bioactive natural products. In this study, a Mucor sp. has been isolated as an endophyte from the medicinal plant Centaurea stoebe. Through bioactivity-guided fractionation, the isolation of the new bioactive terezine E in addition to the previously reported 14-hydroxyterezine D was carried out. The isolated compounds were fully characterised by HRESIMS and 1D and 2D NMR analyses. Both compounds exhibited potent antiproliferative activity against K-562 and HUVEC cell lines and antifungal efficacy against the tested fungal strains.     

A numerical method for solving the Fredholm integral equation of the second kind

The numerical method is used to solve the Fredholm integral equation of the second kind with weak singular kernels using the Toeplitz matrices. The solution has a computing time requirement ofO(N ²), where 2N + 1 is the number of discretization points used. Also, the error estimate is computed. Some numerical examples are computed using the MathCad package.     

Temperature hysteretic effect and its influence on colossal magnetoresistance of La0.33Nd0.33Ca0.33MnO3

Electrical resistance (R) measurements of a bulk La_0.33Nd_0.33Ca_0.33MnO₃ perovskite in magnetic fields up to 40 kOe have revealed anomalous temperature hysteretic effects both in 0 Oe and 20 kOe magnetic fields. The sharp peak observed in the R vs. T plot indicates the occurrence of metal-to-insulator (M-I) transition at a temperature of T _MI=110 K and 140 K, for cooling and warming paths, respectively. An applied magnetic field of 20 kOe reduces the resistance and shifts T _MI to 160 K and 185 K for cooling and warming, respectively. We have observed a much higher resistance in the cooling path than in the warming path leading to the hysteretic resistance ratio (R _cool/R _warm) of 200 at 110 K and 1.8 at 160 K for 0 Oe and 20 kOe, respectively. Record values of colossal magnetoresistance (CMR) have been achieved. The CMR value reaches nearly 99% in the temperature ranges of 90 K to 140 K and 90 K to 170 K for 20 kOe and 40 kOe magnetic fields in the cooling mode, respectively. The observed unusual behavior is attributed to the co-existence of La-rich and Nd-rich domains assumed to be distributed randomly in the compound.