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.     

Synergistic Roll‐to‐Roll Transfer and Doping of CVD‐Graphene Using Parylene for Ambient‐Stable and Ultra‐Lightweight Photovoltaics

A roll‐to‐roll (R2R) transfer technique is employed to improve the electrical properties of transferred graphene on flexible substrates using parylene as an interfacial layer. A layer of parylene is deposited on graphene/copper (Cu) foils grown by chemical vapor deposition and are laminated onto ethylene vinyl acetate (EVA)/poly(ethylene terephthalate). Then, the samples are delaminated from the Cu using an electrochemical transfer process, resulting in flexible and conductive substrates with sheet resistances of below 300 Ω sq^?1, which is significantly better (fourfold) than the sample transferred by R2R without parylene (1200 Ω sq^?1). The characterization results indicate that parylene C and D dope graphene due to the presence of chlorine atoms in their structure, resulting in higher carrier density and thus lower sheet resistance. Density functional theory calculations reveal that the binding energy between parylene and graphene is stronger than that of EVA and graphene, which may lead to less tear in graphene during the R2R transfer. Finally, organic solar cells are fabricated on the ultrathin and flexible parylene/graphene substrates and an ultra‐lightweight device is achieved with a power conversion efficiency of 5.86%. Additionally, the device shows a high power per weight of 6.46 W g^?1 with superior air stability.     

Prediction of sensory quality by near infrared reflectance analysis of frozen and freeze dried green peas (Pisum sativum)

Frozen, green peas (Pisum sativum L ) of different varieties and different levels of maturity were evaluated by sensory analysis using a panel of ten trained judges. Two texture variables (hardness and mealiness) and four flavour variables (pea flavour, sweetness, fruity flavour, off flavour) were considered. Near infiared reflectance ( N I R ) analysis was performed with the same material, on both the fiozen and fieeze dried peas. The N I R instrument was calibrated to predict the sensory variables using the multivariate analytical method of principal component regression. Tenderometer readings of the same peas were also calibrated to predict the sensory variables. N I R analysis on the fieeze dried peas showed relative ability of prediction (RAP) values for the sensory variables which were higher than those for the tenderometer readings. The sensory attributes pea flavour and hardness were predicted with higher RAP values by tenderometer readings than by N I R analysis on fiozen peas. For the rest of the attributes, N I R analysis on fiozen peas gave higher RAP values than tenderometer readings. N I R generally gave high RAP values, and this tentative study suggests that N I R analysis could be a useful tool in instrumentally assessing the quality of frozen peas.     

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.     

Life cycle assessment of fuels for district heating: A comparison of waste incineration,biomass- and natural gas combustion

The aim of this consequential life cycle assessment (LCA) is to compare district heating based on waste incineration with combustion of biomass or natural gas. The study comprises two options for energy recovery (combined heat and power (CHP) or heat only), two alternatives for external, marginal electricity generation (fossil lean or intense), and two alternatives for the alternative waste management (landfill disposal or material recovery). A secondary objective was to test a combination of dynamic energy system modelling and LCA by combining the concept of complex marginal electricity production in a static, environmental systems analysis. Furthermore, we wanted to increase the methodological knowledge about how waste can be environmentally compared to other fuels in district-heat production. The results indicate that combustion of biofuel in a CHP is environmentally favourable and robust with respect to the avoided type of electricity and waste management. Waste incineration is often (but not always) the preferable choice when incineration substitutes landfill disposal of waste. It is however, never the best choice (and often the worst) when incineration substitutes recycling. A natural gas fired CHP is an alternative of interest if marginal electricity has a high fossil content. However, if the marginal electricity is mainly based on non-fossil sources, natural gas is in general worse than biofuels.     

Refractive index sensor based on the diamond like carbon diffraction grating

In this work we present an optical refractive index (RI) sensor based on the spectral analysis of anomalies in the optical response from the diffraction grating employing polarized polychromatic light. The sensor consists of holographic diffraction grating (period 423.5 nm) coated with a thin (110 nm) SiO_x doped diamond like carbon film (DLC) that defines sensitivity of the sensor as well as the range of the spectral analysis. The deposition of the DLC film (synthesized by the direct ion beam deposition from the hydrocarbon source) has influence on the shape but not on the position of the anomalies observed in the specular reflection spectrum. From the reflection spectra the RI dispersion curve of liquid analyte-water was obtained.