Determination of cardiovascular drugs in sewage sludge by matrix solid-phase dispersion and ultra-performance liquid chromatography tandem mass spectrometry

Analytical and Bioanalytical Chemistry - The current study presents a single step sample preparation procedure for the simultaneous determination of five antihypertensive (propranolol, losartan,...     

Copper(II) complexes of 2-(pyridine-2-yl)imidazolidine-4-thione derivatives for asymmetric Henry reactions

The preparation of a new series of 2-(pyridine-2-yl)imidazolidine-4-thione derivatives is described. Their corresponding copper(II) complexes were found to be highly enantioselective catalysts for asymmetric Henry reactions (up to 98% ee). Immobilization of these complexes by anchoring onto Merrifield? resin with respect to their use as recyclable catalysts was subsequently performed. The heterogeneous catalysts prepared in this way were tested in the asymmetric Henry reactions and showed high catalytic activity; they can be easily recycled, although their enantioselectivities were only moderate (～50% ee).     

Planning and scheduling of multistage multiproduct batch plants operating under production campaigns

When plants are operated under stable conditions during reasonable time periods, operation with campaigns is particularly appropriate. The regular operation of the facilities simplifies the production control, the inventory management, the plant operability, etc. A?campaign includes several batches of different products that are going to be manufactured and the same one is cyclically repeated over the time horizon. In this work, a mixed integer linear programming formulation is proposed for the planning and scheduling of given multiproduct batch plants operating with campaigns. The number and size of batches for each product, the campaign composition, the assignment of batches to units and their sequencing, and the number of times that the campaign is repeated over the time horizon must be determined. Taking into account this scenario, an appropriate performance measure is the minimization of the cycle time. An asynchronous slot-based continuous-time representation for modeling the assignment of batches to units and their sequencing is employed, and a novel rule for determining the maximum number of slots postulated for each unit is proposed.