Fast NMR Methods for Measuring in the Direct and/or Competition Mode the Dissociation Constants of Chemical Fragments Interacting with a Receptor

Ligand-based NMR screening represents a powerful method in fragment-based drug discovery for the identification of chemical matter interacting with the receptor of interest. The large dynamic range of these methods allows the detection of weakly binding ligands. However, the methodology has not been extensively used for quantifying the strength of these interactions. This knowledge is important for ranking fragments according to their binding strength and for prioritizing structure-based and medicinal chemistry activities. Rapid NMR methods for measuring the dissociation constant in direct and competition modes are presented here. The theory underpinning these methods are presented, along with their application to the measurement of the binding affinities of several ligands of the heat shock protein 90.     

DYE RECOVERY BY LOW PRESSURE ULTRAFILTRATION†

Ultrafiltration or textile dyes using polyacrylonitrile hollow fibers is reported. Experiments were carried out in recirculating system with various flow intensities along the fiber. Dependence of rejection and membrane flux on concentration of bulk solution is presented. Due to aggregation of dye particles and good separation characteristics of membranes used high water recovery and concentration of dyes were obtained.     

Xyloneside A: A New Glycosylated Incisterol Derivative from Xylaria sp. FB

Xylaria species are prolific natural product producers. Here, we report the characterization of a new glycosylated incisterol derivative, called xyloneside A ( 1 ) and two known lignans ( 2 and 3 ) from the ascomycetous Xylaria sp. FB. The structure of xyloneside A ( 1 ) was determined by 1D and 2D NMR spectroscopy, high-resolution electrospray ionization mass spectrometry and electronic circular dichroism measurements. Xyloneside A is composed of a 1,2,3,4,5,10,19- heptanorergosterane skeleton and a β-D-mannopyranose moiety. This is the first report of an incisterol derivative from an Ascomycete. The biological effects of the isolated metabolites on cytotoxicity, autophagy, cell-migration, and angiogenesis were evaluated.     

Dielectric Characteristics of UV‐Curable CaCu3Ti4O12 Composite Thick Film Capacitors on Cu Foils

Dielectric composite thick films containing a high dielectric constant CaCu₃Ti₄O₁₂ (CCTO) filler in a UV‐cured polymer matrix were investigated as flexible planar capacitors on Cu foils. Dielectric performance depended on the volume fraction and size of CCTO particles dispersed in the cured polymer matrix. As a result, the thick films containing 33.3 vol.% CCTO with an average particle size of 0.47 μm exhibited a dielectric constant of ~80 and a dielectric loss of ~0.06 at 10 kHz. The effective medium theory model incorporating a morphology fitting parameter has been proven to be most close to the experimental values.