The Gabriel-Colman rearrangement in biological systems: design, synthesis and biological evaluation of phthalimide and saccharin derivatives as potential mechanism-based inhibitors of human leukocyte elastase, cathepsin G and proteinase 3

Metal ion-promoted binding of Saccharomyces cerevisiae alcohol dehydrogenase to Cibacron Blue 3GA was used for its isolation by affinity precipitation with Eudragit-bound dye. The yeast cells were broken and the cell debris was separated by flocculation with poly(ethylene imine). The supernatant containing the enzyme activity was mixed with Eudragit--Cibacron Blue in the presence of zinc ions. The precipitation of the affinity complex was induced by the addition of 50 mM CaCl2 and a subsequent increase in temperature to 40 degrees C. The enzyme was desorbed by treating the precipitate with iminodiacetic acid solution. The procedure resulted in about 66% recovery of enzyme activity with more than 20-fold purification. Recycling of Eudragit--dye for enzyme purification was also shown to be possible.     

Adsorption of polyacrylamide on zirconium dioxide

The adsorption of an anionic-type polyelectrolyte (polyacrylamide) onto zirconium dioxide from aqueous dispersion has been studied as a function of pH. Polymer adsorption takes place in the acid region, obeying a Langmuir-type isotherm. Adsorption decreases with increasing pH. The zero-point of charge (zpc) at the ZrO₂–H₂O interface and the nature of the ionic charge on the polymer molecules were investigated. The behavior of polymer attachment is discussed on the grounds of a nonionic bonding mechanism including H bonding and of electrostatic interaction. It has been found that the zpc of ZrO₂ is at pH ～3.5 and that the ionic properties of the polymer molecules depend, to a noticeable extent, upon the pH of the medium.     

Performance analysis of the aluminum casting furnace

The casting furnace plays a central role in the production of aluminum. Its design and operation are complex and involve some 450 parameters. There is a need for a model to predict and analyze its performance. We propose a simplified model in which each main component of the furnace is treated as a 1-D heat conduction medium. Based on the equations of conservation of mass, energy, and chemical species, complemented by the equations of conduction and the Hottel’s formulation of radiative heat transfer, this dynamic model can simulate any sequence of operations such as loading, heating, stirring, skimming … that constitutes a batch, and can take into account other operational details such as the opening of doors. It is validated on a real furnace, then used to predict furnace performance in other modes of operation, and also to determine an optimal fuel flow that minimizes a chosen cost function.     

Hydrogenation of nitriles with iridium-triphenylphosphine complexes

Reactions of cationic iridium(I)-COD (COD = 1,5-cyclooctadiene) complexes, [Ir(COD)(PhCN)(PPh₃)]ClO₄ (1), [Ir(COD)(PPh₃)₂]ClO₄ (2) and [Ir(COD)(PhCN)₂]ClO₄ (3) with nitriles under H₂ catalytically produce primary, secondary and tertiary amines. Hydrogenation of nitriles (RCN) gives HCl salts of amines (RCH₂NH₂HCl, (RCH₂)₂NH HCl) in CH₂Cl₂. Secondary and tertiary amines seem to be produced by the reactions of RCN with primary and secondary amines, respectively under H₂ in the presence of catalysts. The hydrogenation in the presence of1 and2 is homogeneously catalyzed by soluble iridium-PPh₃ complexes formed in the reactions of1 and2 with H₂ and RCN whereas the hydrogenation in the presence of3 is heterogeneous by metallic iridium powders produced in the reduction of3 by H₂.     

Glycoprotein IIb/IIIa receptor antagonists in the management of cardiovascular diseases

Recent studies of the effects of glycoprotein (GP) IIb/IIIa receptor antagonists on the clinical outcomes of patients with cardiovascular diseases are reviewed. The GP IIb/IIIa receptor antagonists studied include abciximab (a murine monoclonal antibody); eptifibatide (a synthetic peptide); and tirofiban, lamifiban, xemilofiban, sibrafiban, and lefradafiban (synthetic nonpeptides). A majority of clinical trials of GP IIb/IIIa receptor antagonists have been performed in patients with unstable angina or acute myocardial infarction and in patients undergoing percutaneous coronary interventions in whom an intracoronary thrombus may lead to ischemic complications. There is abundant evidence that GP IIb/IIIa receptor antagonists reduce the risk of death, acute myocardial infarction, and urgent revascularization procedures in high- and low-risk patients undergoing percutaneous coronary interventions. Abciximab remains the most studied of these agents in interventional settings. Data are accumulating on synthetic peptide and nonpeptide GP IIb/IIIa receptor antagonists that also demonstrate lower rates of death and ischemic complications in the treatment of acute coronary syndromes. In patients who have had a successful response to intravenous GP IIb/IIIa receptor antagonists, oral agents may represent an option for secondary prevention. Additional studies are required in order to determine further uses for these agents. A growing body of evidence supports the role of GP IIb/IIIa receptor antagonists in invasive and pharmacologic treatment approaches to acute coronary syndromes.     

Spirometry in life-long non-smoking, healthy Chinese women in Taiwan

To establish the spirometric values for normal, healthy Chinese women in Taiwan, the spirometry of 506 life-long non-smoking, healthy Chinese women was examined, including 140 subjects over the age of 60 years. Significant correlations among age, height and forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC%, peak expiratory flow (PEF), Vmax75, Vmax50, Vmax25 were found. However, there were no significant correlations between age and FEV1/FVC%, nor age and Vmax25 in the elderly group. FEV1 (FEV1*) and FVC (FVC*) were standardized to the overall mean height for elderly women using Cole's formula. The decline in FEV1* and FVC* with age were observed. The predicted value for the average 70-year-old woman with a height of 1.5 m derived from the present study is compared with those from other surveys of the elderly. The values from the present study are somewhat higher than the values from the Hong Kong study. The authors believe the fact that all of the present subjects were life-long non-smokers might explain the differences.