Palladium-catalyzed coupling of vinyl tosylates with arylsulfinate salts

The first palladium-catalyzed coupling of vinyl tosylates with arylsulfinate salts is described. A variety of cyclic and acyclic vinyl tosylates were coupled with aryl sulfinate salts using 2.5 mol % Pd₂(dba)₃/5.0 mol % XantPhos to give vinyl aryl sulfone products in good yields. The coupling was extended to the preparation of a cyclopropyl vinyl sulfone.     

Altholactone displays promising antimicrobial activity

The antimicrobial activity of altholactone, a naturally extracted styryllactone isolated from Goniothalamus malayanus, was determined against Gram positive (S. aureus ATTC 25923, S. aureus ATTC 25392, and E. faecalis ATTC 29212) and Gram negative (E. coli ATTC 35218, S. typhi ATTC 14023 and P. aeruginosa ATCC 27853) reference bacteria and against the fungus C. albicans ATTC 10231. Different concentrations of altholactone (0, 12, 25, and 50 μg/mL) were used. Results revealed that altholactone inhibited the growth of all tested microbes except P. aeruginosa ATCC 27853 in a dose-dependent manner, with the highest cytotoxic effects occurring at 50 μg/mL. The average of the inhibition zones of the different concentrations was between 0-30 mm. Furthermore, altholactone-induced antimicrobial activity against the more sensitive microbes was assessed by measuring the minimal inhibitory concentration (MIC). Results indicated that Gram positive (S. aureus ATTC 25923, S. aureus ATTC 25392, and E. faecalis ATTC 29212) cells were more sensitive to altholactone than Gram negative ones (E. coli ATTC 35218, S. typhi ATTC 14023). C. albicans showed moderate sensitivity. These results indicate that altholactone might be a potential antimicrobial agent, particularly in ciprofloxacin-refractory S. aureus and E. faecalis infections. Further investigations are required to illustrate the mechanism(s) by which altholactone produces its antimicrobial effects.     

Application of the palladium-catalyzed N-arylation of hydrazones to deactivated heteroaryl halides in the synthesis of pyrazoles

A versatile synthesis of heteroaryl pyrazoles from deactivated heteroaryl halides was demonstrated with different 1,3-bifunctional substrates under acidic conditions. Practical conditions for the transhydrazonation/cyclization step were developed.     

The Horizontal Heat Kernel on the Quaternionic Anti-De Sitter Spaces and Related Twistor Spaces

Potential Analysis - The geometry of the quaternionic anti-de Sitter fibration is studied in details. As a consequence, we obtain formulas for the horizontal Laplacian and subelliptic heat kernel...     

In situ observations of unusual drop deformation and wobbling in simple shear flow

Deformation and wobbling of a liquid drop immersed in a liquid matrix were studied under mild shear conditions for various viscosity ratios. In situ visualization experiments were conducted on a homemade transparent Couette cell incorporated to the Paar Physica MCR500 shear rheometer. The effect of drop or matrix elasticity was examined and was found to play a major role in both deformation and wobbling processes. Experimental results were compared to Jackson and Tucker (J Rheol 47:659–682, 2003), Maffettone and Minale (J Non-Newton Fluid Mech 78:227–241, 1998) and Yu and Bousmina (J Rheol 47:1011–1039, 2003) ellipsoidal models. It was found that the agreement between the Newtonian models and the experimental results required an increase in the drop viscosity. Such increment in viscosity was found to scale with the first normal stress difference.     

Uniaxial deformation and relaxation of polymer blends: relationship between flow and morphology development

Uniaxial elongational flow followed by stress relaxation of a dilute mixture of polystyrene/polymethylmethacrylate) PS/PMMA with PS (5 wt%) as a dispersed phase was investigated. The behavior of the blend was found to be dominated by the PMMA matrix during elongation and by the interface during the relaxation at long time. Such a behavior was related to drop deformation and shape recovery during the relaxation process as was confirmed by morphological analyses on samples quenched within the rheometer just after elongation and at various times during the relaxation process. The morphology and the rheological material functions variation were compared to the Yu model (Yu W, Bousmina M, Grmela M, Palierne JF, Zhou C (2002) Quantitative relationship between rheology and morphology in emulsions. J Rheol 46(6):1381–1399).     

A Mild Dihydrobenzooxaphosphole Oxazoline/Iridium Catalytic System for Asymmetric Hydrogenation of Unfunctionalized Dialins

Air‐stable P‐chiral dihydrobenzooxaphosphole oxazoline ligands were designed and synthesized. When they were used in the iridium‐catalyzed asymmetric hydrogenation of unfunctionalized 1‐aryl‐3,4‐dihydronaphthalenes under one atmosphere pressure of H₂, up to 99:1 e.r. was obtained. High enantioselectivities were also observed in the reduction of the exocyclic imine derivatives of 1‐tetralones.     

Chemical compounds from Phoenician juniper berries (Juniperus phoenicea)

Natural chemical compounds are a widely researched topic worldwide because of their potential activity against cerebrovascular diseases. Chemicals from Juniperus phoenicea berries are reported in this study. Lipids (11%) from seeds are mainly unsaturated (86%). Minerals are also quantified like Na (63.8?mg per 100?g?DW) or K (373.9?mg per 100?g?DW). Total reduced sugars are ca 192.6?mg?g(-1)?DW. Polyphenols and flavonoids from berries are highly present with an average of 1764?±?174.3?mg gallic acid per 100?g?DW and 890?±?47.6?mg rutin per 100?g?DW, respectively. Mean free radical scavenging activities, determined by DPPH and ABTS, are 1337?±?126.2?mM TEAC per 100?g?DW and 1105.7?±?95.9?mM TEAC per 100?g?DW, respectively. All findings improve the possible presence of biologically active fractions in phytocomplex that could be used as such and/or extracted for the formulation of supplements and/or ingredients for the pharmaceutical industry.     

E-Compactness in Pointfree Topology

We present a pointfree analogue of E-compactness as introduced by Engelking and Mrówka. In particular, we show that a frame L is a closed quotient of a copower of a regular frame E iff L is complete in its E-nearness. We further show that the version of E-compactness that is more compatible with the classical one corresponds to Cauchy completeness in its E-nearness.