Abstract: A system and method of providing personalized item recommendations in a communication system comprising a server and a plurality of client devices. At the server, a plurality of user rating vectors are received from a plurality of client devices and aggregated into a rating matrix that is factorized into a user feature matrix and an item feature matrix, with the product of the user feature and item feature matrixes approximating the user rating matrix. The factorization comprises the steps of the ALS1 or the IALS1 algorithm including: initializing the user feature matrix and the item feature matrix with predefined initial values; alternately optimizing the user feature matrix and the item feature matrix until a termination condition is met. The item feature matrix is transmitted from the server to at least one client device, and a predictive rating vector is generated as the product of the associated user feature vector and the item feature matrix.

Abstract: The present invention relates to a chromatographic sheet and/or a system of chromatographic sheets for overpressured multilayer chromatography.One or more chromatographic sheets with sorbent layer are optionally sealed at their edges preferably by impregnation or coating with a polymer film and holed at the solvent inlet in adequate size and shape and they are optionally included in a system in single or multiple layers with or without a conventional chromatographic sheet sealed at its edges.

Abstract: A multifunction centrifuge consists of a rotor 1 to which a plurality of centrifuge bowls 2 are rigidly fixed. Each bowl 2 has two chambers 3a, 3b connected with each other for free flow communication from either chamber to the other. One chamber 3a lies above the other 3b and is of a sack shape with a radially outwardly projecting closed bottom so that on stoppage of rotor rotation liquid therein flows back into the more deeply-lying other chamber 3b. The bowl 2 is light-transparent for photometric measurements.