silica-bonded n-propyldiethylenetriamine sulfamic acid (sbpdsa) was found as an efficient solid acid for the synthesis of coumarins. coumarin derivatives were obtained via the pechmann condensation reaction of phenols and β-keto-esters at 80 oc under solvent-free conditions. also, biscoumarins were obtained via the condensation of aldehydes and 4-hydroxycoumarin in water at reflux conditions. t...

This article analyses the role of intermediaries in evolution UK TV production sector tracking processes which past two decades have underpinned consolidation sector. The research involved elite interviews with executives at ten Independent companies and financial as well trade bodies civil servants. epistemic work shape transactions a way that aligned buyers’ desire to grow their portfolio by ...

In Epistemic Cultures (1999), Karin Knorr Cetina argues that different scientific fields exhibit different epistemic cultures. She claims that in high energy physics (HEP) individual persons are displaced as epistemic subjects in favor of experiments themselves. In molecular biology (MB), by contrast, individual persons remain the primary epistemic subjects. Using Ed Hutchins’ (1995) account of...

Knorr, L. & RBosler, P. (1903). Ber. dtech. chem. G"e. 36, 1278. Luck, J. M. & Wilcox, A. (1953). J. biol. Chem. 205, 859. Ohno, K. (1953). J. Biochem., Tokyo, 40, 621. Rees, M. W. (1946). Biochem. J. 40, 632. Sanger, F. (1945). Biochem. J. 39, 507. Schlesinger, H. I. (1944). Quoted by J. R. Elliott, E. M. Boldebuck and G. F. Roedel (1952). J. Amer. Chem. Soc. 74, 5049, footnote 11. Snyder, H. ...

(diacetoxyiodo)benzene has been used as an efficient catalyst for an improved and rapid one-pot synthesis of biscoumarin derivatives in excellent yield under reflux condition using water as a environmentally benign reaction medium. this aqua mediated knoevenagel condensation of various aromatic and hetero-aromatic aldehydes with 4-hydroxycoumarin using catalytic amount of (diacetoxyiodo)benzene...

the knoevenagel condensation of aromatic aldehydes with barbituric acid, dimedone and malononitrile occurred in the presence of bf3/nano-γ-al2o3 at room temperature in ethanol. this catalyst is characterized by powder x-ray diffraction (xrd), fourier transform infrared spectroscopy (ft-ir), thermal gravimetric analysis (tga), field emission scanning electron microscopy (fesem) and energy-disper...

Chromosome condensation is essential for the faithful transmission of genetic information to daughter cells during cell division. The depletion of chromosome scaffold proteins does not prevent chromosome condensation despite structural defects. This suggests that other factors contribute to condensation. Here we investigated the contribution of divalent cations, particularly Ca2+, to chromosome...