The minimal flavour violation benchmark in view of the latest LHCb data

We derive the consequences of the MFV hypothesis for ΔF=1$\mathrm{\Delta }F=1$ flavour observables based on the latest LHCb data. Any future measurement beyond the MFV bounds and relations unambiguously indicates the existence of new flavour structures next to the Yukawa couplings of the Standard Model.     

Subluminal to superluminal pulse propagation through one-dimensional photonic crystals with a three-level atomic defect layer

Propagation of an electromagnetic pulse through one-dimensional photonic crystals with a three- level atomic defect layer is discussed. It is shown that the group velocity of the transmitted pulse can be controlled by the frequency detuning and the width of the defect layer. Moreover, the effects of controlling parameter such as Rabi-frequency on light propagation through one-dimensional photonic crystals are then introduced.     

Copper coordinated-poly(α-amino acid) decorated on magnetite graphene oxide as an efficient heterogeneous magnetically recoverable catalyst for the selective synthesis of 5- and 1-substituted tetrazoles from various sources: A comparative study

In this work, poly(α-amino acid)-Cu(II) complex immobilized on magnetite graphene oxide (GO/Fe₃O₄@PAA-Cu-complex) was prepared via a multistep synthesis and employed as an efficient, heterogeneous, magnetically recyclable nanocatalyst for one-pot, three component synthesis of 5- and 1-substituted tetrazoles using different substrates including benzaldehydes, benzonitriles, and anilines in mild conditions. The different approaches were mechanically investigated and compared. The catalyst was fully characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), energy dispersive X-ray spectroscopy (EDX), inductively coupled plasma (ICP), FE-SEM and TEM analyses. The magnetic nanocatalyst could be readily separated from the reaction mixture by an external magnet and reused for several times without significant loss of catalytic activity. Also, the spectroscopic analysis revealed the stability and durability of the catalyst. Finally, the chemoselectivity of the method was investigated by the various combinations of aldehyde, nitrile, and oxime.     

Design of Lead(II) Metal–Organic Frameworks Based on Covalent and Tetrel Bonding

Three solid materials, [Pb( HL )(SCN)₂] ? CH₃OH ( 1 ), [Pb( HL )(SCN)₂] ( 2 ), and [Pb( L )(SCN)]_n ( 3 ), were obtained from Pb(SCN)₂ and an unsymmetrical bis‐pyridyl hydrazone ligand that can act both as a bridging and as a chelating ligand. In all three the lead center is hemidirectionally coordinated and is thus sterically optimal for participation in tetrel bonding. In the crystal structures of all three compounds, the lead atoms participate in short contacts with thiocyanate sulfur or nitrogen atoms. These contacts are shorter than the sums of the van der Waals radii (3.04–3.47 Å for Pb ??? S and 3.54 Å for Pb ??? N) and interconnect the covalently bonded units (monomers, dimers, and 2D polymers) into supramolecular assemblies (chains and 3D structures). DFT calculations showed these contacts to be tetrel bonds of considerable energy (6.5–10.5 kcal mol^?1 for Pb ??? S and 16.5 kcal mol^?1 for Pb ??? N). A survey of structures in the CSD showed that similar contacts often appear in crystals of Pb^II complexes with regular geometries, which leads to the conclusion that tetrel bonding plays a significant role in the supramolecular chemistry of Pb^II.     

Crystal‐to‐Crystal Transformation: An HgII Metal–Organic Polymer Constructed with a Triazole Ligand

A new one‐dimensional double‐chain Hg^II coordination polymer containing the ligand 3,5‐bis(4‐pyridyl)‐4‐amino‐1,2,4‐triazole (bpatrz) and thiocyanate anions, namely, {[Hg₂(μ‐bpatrz)(μ‐SCN)₂(SCN)₂] · MeOH}_n ( 1 ), has been synthesized and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 displays bright blue luminescence with emission maxima around 370 and 440 nm in solution and the solid state, respectively. Uptake and release of MeOH by 1 were investigated by powder X‐ray diffraction, thermogravimetric analysis, elemental analysis, and IR and NMR spectroscopy.     

Chemoselective synthesis of xanthenes and tetraketones in a choline chloride-based deep eutectic solvent

A chemoselective synthesis of tetraketone and xanthene derivatives, by means of tandem Knoevenagel condensation and Michael addition in choline chloride-based deep eutectic solvents (DESs), is presented. The reaction of readily available aldehydes and active methylene compounds in malonic acid- and ZnCl₂-based DES gives various xanthenes derivatives with good to excellent yields under mild reaction conditions. On the other hand, tetraketones were synthesized in almost quantitative yields by simple condensation of an aldehyde and active methylene compounds in milder deep eutectic solvents of urea and SnCl₂. In addition, the reaction of other types of choline chloride-based DES leads to a mixture of tetraketone and xanthene.     

Efficient synthesis of novel quinazoline-4(1H)-one derivatives by N-halosulfonamides

Research on Chemical Intermediates - In this research, a facile, effective and one-pot synthesis of new quinazoline-4(1H)-one derivatives is reported. Isatoic anhydride, acid hydrazides or ammonium...     

On covers of cyclic acts over monoids

In (Bull. Lond. Math. Soc. 33:385–390, 2001) Bican, Bashir and Enochs finally solved a long standing conjecture in module theory that all modules over a unitary ring have a flat cover. The only substantial work on covers of acts over monoids seems to be that of Isbell (Semigroup Forum 2:95–118, 1971), Fountain (Proc. Edinb. Math. Soc. (2) 20:87–93, 1976) and Kilp (Semigroup Forum 53:225–229, 1996) who only consider projective covers. To our knowledge the situation for flat covers of acts has not been addressed and this paper is an attempt to initiate such a study. We consider almost exclusively covers of cyclic acts and restrict our attention to strongly flat and condition (P) covers. We give a necessary and sufficient condition for the existence of such covers and for a monoid to have the property that all its cyclic right acts have a strongly flat cover (resp. (P)-cover). We give numerous classes of monoids that satisfy these conditions and we also show that there are monoids that do not satisfy this condition in the strongly flat case. We give a new necessary and sufficient condition for a cyclic act to have a projective cover and provide a new proof of one of Isbell’s classic results concerning projective covers. We show also that condition (P) covers are not unique, unlike the situation for projective covers.     

A novel numerical method and its convergence for nonlinear delay Volterra integro-differential equations

In this paper, we suggest a convergent numerical method for solving nonlinear delay Volterra integro-differential equations. First, we convert the problem into a continuous-time optimization problem and then use a shifted pseudospectral method to discrete the problem. Having solved the last problem, we can achieve the pointwise and continuous approximate solutions for the main delay Volterra integro-differential equations. Here, we analyze the convergence of the method and solve some numerical examples to show the efficiency of the method.