Phase-changing sacrificial layer fabrication of multilayer polymer microfluidic devices

We present a new approach for fabricating multilayer microfluidic devices in poly(methyl methacrylate). Paraffin wax was used as a phase-changing sacrificial layer to protect microstructures during solvent bonding. Microchannels in the top and bottom pieces were aligned with through-holes in the middle layer, resulting in microchannels that cross one another. No discernible delamination of the layers or leakage between channels was observed at pressures as high as 300 psi. The current versus voltage linearity in the crossover channel indicates that no Joule heating occurs at voltages of at least 2.0 kV. Moreover, a potential in the crossover channel did not affect the current in the separation channel. Rapid and efficient separation of fluorescently labeled amino acids was performed in these devices. Pressurized buffer flow or voltage applied in the crossover channel caused no leakage into or electrical interference with the separation channel. Our results demonstrate that sacrificial layers with solvent bonding can be implemented readily in the fabrication of robust and fluidically complex multilayer polymer microchips. These capabilities should facilitate the development of a new generation of sophisticated microfluidic systems.     

Organic-based molecular switches for molecular electronics

In a general sense, molecular electronics (ME) is the branch of nanotechnology which studies the application of molecular building blocks for the fabrication of electronic components. Among the different types of molecules, organic compounds have been revealed as promising candidates for ME, due to the easy access, great structural diversity and suitable electronic and mechanical properties. Thanks to these useful capabilities, organic molecules have been used to emulate electronic devices at the nanoscopic scale. In this feature article, we present the diverse strategies used to develop organic switches towards ME with special attention to non-volatile systems.     

Energy Consumption in Industrial Drying of Radiata Pine

This article reports the results of an exploratory study designed to reduce heat and electricity consumption in industrial drying of radiata pine. The experiments were performed with slight modifications of the standard drying schedules used by the sawmill to dry radiata pine in 100-m³ industrial kilns. The heat and electricity consumption were determined with data collected during the drying runs and calculations based on mathematical models. The results showed that depending on the case, heat and power consumption were respectively reduced by up to 14 and 35%.     

Equilibrium composition of ethanol steam reforming reaction to produce H2 applied to Ni,Co and Pt/hydrotalcite–WOx catalysts

The purpose of this work was to investigate the difference between the experimental molar fractions of products obtained during the evaluation of Pt, Co and Ni/Hydrotalcites–WOx catalysts and the calculated composition in equilibrium for the ethanol steam reforming reaction. Mole fractions of H₂, CO₂, CH₃CHO, CH₂CH₂, CH₄ and H₂O were calculated using the stoichiometric and the minimization of the Gibbs free energy methods. The difference between calculated and experimental mole fractions was used to determine the intermediate and final compounds in the reaction mechanism and also how close to equilibrium are the reactants and final products. In addition, by comparing H₂ and the conversion, it was possible to distinguish which series of catalysts were more active. From our experimental results, the conversion order of these catalysts was as follows: Pt > Ni > Co and the reaction rate per g-atm of metal was: Pt ? Ni ≈ Co.     

Catalysts for H2 production using the ethanol steam reforming (a review)

This review aims to provide an overview of the main catalytic studies of H₂ production by ethanol steam reforming (ESR). The reaction is endothermic and produces H₂, CO₂, CH₄, CO and coke. The conversion and H₂ selectivity of these products depended greatly of the physicochemical properties of the catalysts, active metal, promoters, temperature, long-term reaction, water/ethanol ratio, space velocity, contact time, and presence of O₂. Initial total conversion has been reported in all catalysts evaluated between 300 and 850 °C. The noble catalysts with high selectivity to H₂ (more than 80%) were: Rh, Ru, Pd and Ir and non-noble metal catalysts were: Ni, Co and Cu. The support materials include CeO₂, ZnO, MgO, Al₂O₃, zeolites-Y, TiO₂, SiO₂, La₂O₂CO₃, CeO₂–ZrO₂ and hydrotalcites. The impregnation method produced the best noble metal catalysts in terms of selectivity and conversion. The decrease of coke was related with the presence of basic sites on the support.     

Word-based grouping affects the prime-task effect on semantic priming.

Semantic priming between words is reduced or eliminated if a low-level task such as letter search is performed on the prime word (the prime task effect), a finding used to question the automaticity of semantic processing of words. This idea is critically examined in 3 experiments with a new design that allows the search target to occur both inside and outside the prime word. The new design produces the prime task effect (Experiment 1) but shows semantic negative priming when the target letter occurs outside the prime word (Experiments 2 and 3). It is proposed that semantic activation and priming are dissociable and that inhibition and word-based grouping are responsible for reduction of semantic priming in the prime task effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydrogenation of cyclohexanone on nickel-tungsten sulfide catalysts

Unsupported Ni-W sulfide catalysts were tested for cyclohexanone hydrogenation under atmospheric pressure conditions and showed a high selectivity towards cyclohexene. They were prepared employing ammonium thiotungstate complexes and nickel nitrate as metal-sulfide precursors. The data of catalytic activity show a synergetic effect as a function of stoichiometric composition, R=Ni/(Ni+W). A maximum synergetic effect occurred at R=0.7. The texture and surface composition characterization of the catalysts were carried out by BET surface area measurements, AES and XPS. The surface of catalysts was found to be nickel deficient, compared to the nominal values, as determined by AES and XPS. The electronic state of Ni changed as the catalyst stoichiometry varied, but the electronic state of W did not change.     

Single-Cell Proteomics: The Critical Role of Nanotechnology

In single-cell analysis, biological variability can be attributed to individual cells, their specific state, and the ability to respond to external stimuli, which are determined by protein abundance and their relative alterations. Mass spectrometry (MS)-based proteomics (e.g., SCoPE-MS and SCoPE2) can be used as a non-targeted method to detect molecules across hundreds of individual cells. To achieve high-throughput investigation, novel approaches in Single-Cell Proteomics (SCP) are needed to identify and quantify proteins as accurately as possible. Controlling sample preparation prior to LC-MS analysis is critical, as it influences sensitivity, robustness, and reproducibility. Several nanotechnological approaches have been developed for the removal of cellular debris, salts, and detergents, and to facilitate systematic sample processing at the nano- and microfluidic scale. In addition, nanotechnology has enabled high-throughput proteomics analysis, which have required the improvement of software tools, such as DART-ID or DO-MS, which are also fundamental for addressing key biological questions. Single-cell proteomics has many applications in nanomedicine and biomedical research, including advanced cancer immunotherapies or biomarker characterization, among others; and novel methods allow the quantification of more than a thousand proteins while analyzing hundreds of single cells.     

Comments on ‘Admissibility and static output‐feedback stabilization of singular Markovian jump systems with defective statistics of modes transitions’

This document shows that the proof of Theorem 3.3 in the work of Liu et al (Int J Robust Nonlinear Control. 2015. 10.1002/rnc.3108) is incorrect and, thus, the theorem is not proved. Since the results of the paper are strongly based on this theorem, the problem has to be addressed. If a natural correction is introduced, the problem still holds. Therefore, a new linear matrix inequality is proposed here to show its equivalence with the stochastic stability of a Markov jump linear singular system under a similar assumption as that in the work of Liu et al.