Stabilized and Immobilized Bacillus subtilis Arginase for the Biobased Production of Nitrogen‐Containing Chemicals

L ‐Ornithine could serve as an intermediate in the biobased production of 1,4‐diaminobutane from L ‐arginine. Using the concept of biorefinery, L ‐arginine could become widely available from biomass waste streams via the nitrogen storage polypeptide cyanophycin. Selective hydrolysis of L ‐arginine to L ‐ornithine is difficult to perform chemically, therefore the stabilization and immobilization of Bacillus subtilis arginase (EC 3.5.3.1) was studied in a continuously stirred membrane reactor system. Initial pH of the substrate solution, addition of L ‐aspartic acid and reducing agents all appeared to have an effect on the operational stability of B. subtilis arginase. A remarkably good operational stability (total turnover number, TTN=1.13⋅10⁸) at the pH of arginine free base (pH 11.0) was observed, which was further improved with the addition of sodium dithionite to the substrate solution (TTN>1⋅10⁹). B. subtilis arginase was successfully immobilized on three commercially available epoxy‐activated supports. Immobilization on Sepabeads EC‐EP was most promising, resulting in a recovered activity of 75% and enhanced thermostability. In conclusion, the stabilization and immobilization of B. subtilis arginase has opened up possibilities for its application in the biobased production of nitrogen‐containing chemicals as an alternative to the petrochemical production.     

Development of a dielectric spectroscopy technique for the determination of apple (Granny Smith) maturity

Dielectric measurements of apple were done during its maturity in order to find relations with apple physiological compounds (sugar content, malic acid). An Agilent 85070E open-ended coaxial probe connected to an Agilent E8362B vector network analyzer were used in these experiments. All determinations were made at 30 °C from 500 MHz to 20 GHz. These assays were performed in order to consider the potential use of dielectric spectroscopy for determining the state of fruit maturity. Good correlations among apples Thiault Index with a new defined Dielectric Maturity Index were found. The Dielectric Maturity Index was related to loss factor at two punctual frequencies (0.5 GHz and dipolar relaxation frequency). This work is presenting a non-destructive control method for the prediction of climacteric fruits maturity.Industrial relevanceThe results of this research article are demonstrated to be useful for determining apple maturity. Thus, the industrial relevance is clear because the determination of fruit maturity is important to decide the best uses and storage time of the fruit. In the paper, a Maturity Index based on dielectric properties was developed. The results are obtained for the concrete application of apple fruit but they can be extended to other climacteric fruits although more studies are necessary. Dielectric spectroscopy, which can be considered an emerging technology, has the advantage of being an objective and a non destructive technique. For all these reasons we are sending to this journal “Innovative Food Science and Emerging Technologies” our results.     

Solid-state laser pumping by light guides

What we believe to be novel pumping schemes for lamp-pumped solid-state lasers are proposed. Based on the refractive and total internal reflection principles, curved fused-silica light guides of rectangular cross sections are used to couple the pump radiation from an arc lamp into a laser crystal. The performances of light-guide pumping schemes are analyzed through a nonsequential ray-trace program and are compared to that of a single elliptical cavity. Improved pump radiation distribution around the laser crystal was registered. The light-guide cavities also permit tailoring the pump flux distribution within the active medium. A lamp-pumped Nd:YAG laser by a light-guide cavity was built and tested. An overall laser efficiency of 1.1% was measured.     

Semicontinuous copolymerization of 80/20 wt % [2‐(acryloyloxy)ethyl]trimethyl ammonium chloride/acrylamide in an inverse microemulsion at high comonomer concentrations

The semicontinuous inverse microemulsion copolymerization of 80/20 wt % [2‐(acryloyloxy)ethyl]trimethylammonium chloride/acrylamide in an isoparaffin solvent at high comonomer concentrations (30–42 wt %) was studied with a mixture of nonionic surfactants (Crill 43 and Softanol 90) as the emulsifier and sodium metabisulfite as the initiator. The influence of the total comonomer concentration (TCC), emulsifier concentration (EC), hydrophilic–lipophilic balance (HLB), isopropyl alcohol (chain‐transfer agent) concentration (IPC), and crosslinking agent concentration (CAC) on the weight‐average molar mass (M_w), absolute viscosity (BV), and viscometric structuring index (VSI) of the obtained copolymers was analyzed. M_w and BV increased with TCC and HLB and decreased with EC. At the higher TCC, M_w decreased with IPC; meanwhile, at the lower TCC, M_w increased with IPC above 0.5 wt %. VSI increased with TCC, HLB, and IPC and decreased with EC. VSI increased dramatically with CAC, whereas BV showed a peak at the CAC of 10 ppm. In the absence of both chain‐transfer and crosslinking agents, M_w increased linearly with VSI, and this suggests that linear copolymers of very high M_w values cannot be obtained by inverse microemulsion copolymerization, at least for high TCCs. The results are explained in terms of both the collapsed state of the copolymer chains inside the latex particles and changes in the interface structure and composition. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

TiO2 nanotubes manufactured by anodization of Ti thin films for on-chip Li-ion 2D microbatteries

The use of self-organized TiO₂ nanotube arrays electrochemically grown onto Si is investigated for the fabrication of an alternative electrode dedicated to on-chip Li-ion 2D microbatteries. Discharge/charge curves and cycling performance are studied in lithium-anode electrochemical test cells for both amorphous and crystalline titania nanotubes. At 5 μA cm⁻² amorphous TiO₂ nanotube layers onto Si deliver a maximum areal capacity of 89 μAh cm⁻² in the first reversible discharge and 56 μAh cm⁻² over 50 cycles. We demonstrate that these nanostructured thin film electrodes showing such electrochemical performances are compatible with IC technology.     

Characterization of hyperbranched polyol polyesters based on 2,2‐bis (methylol propionic acid) and pentaerythritol

Hyperbranched polyesters (HBPs) of fourth and fifth generation were synthesized by procedures involving one step (HBP4, HBP5), step by step (HBP4P, HBP5P), and combination of both of them (HBP1‐4, HBP1‐5) using 2,2‐bis(methylol)propionic acid (DMPA), pentaerythritol (PE), and acid catalysis. The characterization of the polyesters was done by nuclear magnetic resonance (NMR), rheology on solution, Fourier transform infrared spectroscopy (FTIR), and acid and hydroxyl values. The degree of branching of polyesters (DB) and the average molecular mass and polymerization degree _NMR were calculated by Frey and Fréchet methods and (DP)_NMR, respectively, being higher for HBP4P sample. The molecular structure of polyesters depends mainly on of the synthesis method. The hydroxyl values were larger than 430 mg/g KOH for all HBPs, and the conversion was controlled between 90 and 93% to avoid excessive cyclization reactions. The steady shear viscosities at different temperatures and at 41.77 s^?1 shear rate were measured for all HBPs solutions in dimethyl formamide (DMF) showing a shear thickening behavior. The flow activation energies (E_a) were calculated by Arrhenius equation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Video transcoding from H.264/AVC to MPEG-2 with reduced computational complexity

This paper addresses video transcoding from H.264/AVC into MPEG-2 with reduced complexity and high rate-distortion efficiency. While the overall concept is based on a cascaded decoder–encoder, the novel adaptation methods developed in this work have the advantage of providing very good performance in H.264/AVC to MPEG-2 transcoding. The proposed approach exploits the similarities between the coding tools used in both standards, with the objective of obtaining a computationally efficient transcoder without penalising the signal quality. Fast and efficient methods are devised for conversion of macroblock coding modes and translation of motion information in order to compute the MPEG-2 coding format with a reduced number of operations, by reusing the corresponding data embedded in the incoming H.264/AVC coded stream. In comparison with a cascaded decoder–encoder, the fast transcoder achieves computational complexity savings up to 60% with slightly better peak signal-to-noise ratio (PSNR) at the same bitrate.     

Evaluating Internet technologies business effectiveness

This paper focuses on analyzing the relationship between Internet technologies and firm performance. This relationship is examined not only from the simple presence of Internet technologies, but also according to different e-business orientations: e-business orientation to customers and e-business orientation to internal processes. In addition, the relationship between Internet technologies and the proposed e-business orientations is examined. To achieve these objectives, a theoretical model is developed and tested by using structural equation modelling on a dataset of 1010 firms. The results show a positive relationship between e-business orientations and firm performance. In contrast, the results confirm that the merely presence of Internet technologies is not positively associated with firm performance.     

Monte Carlo simulation of the movement and detection efficiency of a whole-body counting system using a BOMAB phantom

This study reports on the computational analysis and experimental calibration of the whole-body counting detection equipment at the Nuclear and Technological Institute (ITN) in Portugal. Two state-of-the-art Monte Carlo simulation programmes were used for this purpose: PENELOPE and MCNPX. This computational work was undertaken as part of a new set of experimental calibrations, which improved the quality standards of this study's WBC system. In these calibrations, a BOMAB phantom, one of the industry standards phantoms for WBC calibrations in internal dosimetry applications, was used. Both the BOMAB phantom and the detection system were accurately implemented in the Monte Carlo codes. The whole-body counter at ITN possesses a moving detector system, which poses a challenge for Monte Carlo simulations, as most codes only accept static configurations. The continuous detector movement was approximately described in the simulations by averaging several discrete positions of the detector throughout the movement. The computational efficiency values obtained with the two Monte Carlos codes have deviations of less than 3.2 %, and the obtained deviations between experimental and computational efficiencies are less than 5 %. This work contributes to demonstrate the great effectiveness of using computational tools for understanding the calibration of radiation detection systems used for in vivo monitoring.     

Ultrahigh-sensitivity temperature fiber sensor based on multimode interference

The proposed sensing device relies on the self-imaging effect that occurs in a pure silica multimode fiber (coreless MMF) section of a single-mode-multimode-single-mode (SMS)-based fiber structure. The influence of the coreless-MMF diameter on the external refractive index (RI) variation permitted the sensing head with the lowest MMF diameter (i.e., 55 μm) to exhibit the maximum sensitivity (2800 nm/RIU). This approach also implied an ultrahigh sensitivity of this fiber device to temperature variations in the liquid RI of 1.43: a maximum sensitivity of -1880 pm/°C was indeed attained. Therefore, the results produced were over 100-fold those of the typical value of approximately 13 pm/°C achieved in air using a similar device. Numerical analysis of an evanescent wave absorption sensor was performed, in order to extend the range of liquids with a detectable RI to above 1.43. The suggested model is an SMS fiber device where a polymer coating, with an RI as low as 1.3, is deposited over the coreless MMF; numerical results are presented pertaining to several polymer thicknesses in terms of external RI variation.