Mining frequent generators and closures in data streams with FGC-Stream

Knowledge and Information Systems - Mining frequent itemsets (FIs) from data streams is a challenging task due to the limited resources available w.r.t. the typically large size of the result and...     

A microfluidic electrocapture device in sample preparation for protein analysis by MALDI mass spectrometry

The design and operation of a microfluidic device for sample preparation in MALDI mass spectrometry of peptides and proteins is described. It is particularly useful for proteomics applications and for mass determination of proteins in salt- and detergent-containing solutions. The system consists of a flow channel with two conductive areas or electrical junctions where proteins and peptides are retained by means of an electric field. The microfluidic device is made of PEEK tubing, and the junctions are covered with a conductive polymeric membrane. A syringe pump connected to the device produces a flow stream, and injection of sample is carried out manually via hydrodynamic pressure. Proteolytic peptides and intact proteins in salt- and detergent-containing acidic media were captured at the cathode junction followed by exchange of the original solution to a solvent suitable for subsequent mass spectrometry. Using this principle, a significant desalting effect was obtained for tryptic peptides in mass-mapping experiments. Protein sequence coverages were high (up to 40%) at subpicomole levels with results better than those obtained using reversed-phase solid-phase extraction. In contrast to the latter technique, the microfluidic device has the capacity to efficiently remove detergents such as CHAPS before peptide mapping and protein analysis.     

Etude cristallographique du systeme FeSSc2S3 preparations et structures de FeSc2S4 et Fe0.85Sc2.10S4

The crystal structures of FeSc₂S₄ and Fe_0.85Sc_2.10S₄ have been determined by three dimensional X-ray diffraction. The cubic cells, space group Fd3m, have lattice constants $\text{a}\text{= 10,501}\text{A}\text{?}$ for FeSc₂S₄ and $\text{a}\text{= 10,444}\text{A}\text{?}$ for Fe_0.85Sc_2.10S₄. Iron is divalent and scandium trivalent. FeSc₂S₄ is a direct spinel structure, Fe_0.85Sc_2.10S₄ is near a spinel structure. Only 0,5 iron atom is on every 8a position; 0,175 Fe and 1,05 Sc lie on octahedral 16d and 16c site.     

Comprehensive analysis of major and minor chlorogenic acids and lactones in economically relevant Brazilian coffee cultivars

Coffee is the most consumed beverage in the world and a significant source of phenolic compounds, particularly chlorogenic acids (CGA). During coffee roasting, some CGA are partially transformed into chlorogenic acid lactones (CGL). Both CGA and CGL are important compounds for flavor and potentially beneficial to human health. In the present study, using LC–MS and synthetic standards, we investigated major and minor CGA and CGL isomers in green and roasted samples of economically relevant Brazilian Coffea arabica and Coffea canephora coffee cultivars. For the first time, in addition to nineteen previously identified CGA and CGL, 1-feruloylquinic acid, 1-feruloylquinic lactone and 3,4-diferuloylquinic acid were quantified in C. arabica and C. canephora, the contents of 3- and 4-p-coumaroylquinic lactones were reported in C. canephora and 3,4-di-p-coumaroylquinic acid was identified in C. arabica. Despite their low concentrations, the implications of these findings for flavor, cup quality and the biological properties of coffee merit further investigation.     

THE INFLUENCE OF PRESSURE AND TEMPERATURE ON THE KINETICS OF VACUUM DRYING OF KETOPROFEN

This paper explores the influence of temperature and pressure on drying kinetics of 2-(3-benzoylphenil propionic acid) ketoprofen, in a vacuum dryer on laboratory scale, Experimentally determined relations between moisture content and drying rate vs time, were approximated with an exponential model. Model parameters were correlated with drying conditions (temperature, pressure) and defined by functions of their potentions.

From an energy balance of the process, a mathematical model for simulating dependence of sample temperature vs drying time, and moisture content of material, has been developed.

Simulation of the drying kinetics and sample temperature, by use of those functional dependencies shows good agreement with experimental results.