Response surface optimisation of germination conditions to improve the accumulation of bioactive compounds and the antioxidant activity in quinoa

Germination has been proposed as an economic approach to improve the content of bioactive compounds in pseudocereals. In this work, response surface methodology (RSM) was employed to investigate the impact of germination conditions on the phytochemical content and antioxidant activity of quinoa. The use of desirability methodology showed that the optimum conditions to maximise the content of total phenolic content (TPC) and antioxidant activity in sprouted quinoa were 20 °C for 42 h. Sprouts produced under these conditions exhibited increases of 80% and 30% in TPC and antioxidant activity, respectively, compared to un‐germinated seeds, and contained high γ‐aminobutyric acid (GABA) concentration. The nonsignificant lack‐of‐fit and high determination coefficients obtained confirmed the suitability of the predictive models developed for TPC and antioxidant activity, whilst the one obtained for GABA was not significant (R² < 0.75) within the conditions studied. Sprouting under optimum conditions enhanced the content of both flavonoid and nonflavonoid compounds, being the increase in flavonoids more pronounced. Kaempferol‐O‐dirhamnosyl‐galactopyranose and quercetin‐O‐glucuronide were the compounds that experienced the most noticeable increase in quinoa after germination. In conclusion, this study provides useful information on the optimum germination conditions to improve the levels of health‐promoting compounds in quinoa.     

Relaxations in semicrystalline polyethyleneterephthalate using thermally stimulated currents

Relaxation processes at temperatures above 20 °C in semicrystalline polyethylene-terephthalate have been studied using thermally stimulated depolarization currents (TSDC). The discharge curve shows three relaxation peaks (c, c and *) whose positions and intensities depend on the polarization conditions and the crystallinity. Relaxations c and c are heteropolar, while * may be homopolar or heteropolar according to the polarization temperature used. The effect of the crystallinity on these relaxations has been analysed by the thermal steps stimulation (TSS) method applied to an amorphous sample. Results show that c is fundamentally a dipolar relaxation associated with the amorphous interlamellar zone. The relaxation c is associated with the release of a free charge trapped in the amorphous regions, and * is a Maxwell–Wagner–Sillars relaxation associated with crystalline – amorphous interphases. For polarization temperatures above 150 °C, two relaxations are observed only as a consequence of overlapping C and * relaxations. © 1998 Chapman & Hall     

Analytical formulation to compute QFT bounds: The envelope method

This paper describes an analytical formulation to compute quantitative feedback theory (QFT) bounds in one‐degree‐of‐freedom feedback control problems. The new approach is based on envelope curves and shows that a QFT control specification can be expressed as a family of circumferences. Then, the controller bound is defined by the envelope curve of this family and can be obtained as an analytical function. This offers the possibility of studying the QFT bounds in an analytical way with several useful properties. Gridding methods are avoided, resulting in a lower computational effort procedure. The new formulation improves the accuracy of previous methods and allows the designer to calculate multivalued bounds. Copyright © 2009 John Wiley & Sons, Ltd.     

Dealumination–aging pattern of REUSY zeolites contained in fluid cracking catalysts

The evolution of the properties of a REUSY zeolite contained in a fluid cracking catalyst was investigated under laboratory steam deactivation procedures and in age fractions of the corresponding equilibrium catalyst (Ecat). The aging pattern, defined by the evolution of the zeolite surface area (ZSA) related to the decrease of the unit cell size (UCS), was similar between lab-steamed zeolites and Ecat fractions. A sharp drop in ZSA occurred at ca. 2.430 nm UCS. A study done by FT-IR spectroscopy suggested that zeolite dealumination initially took place more extensively on the sodalite cages and double six-member rings (D6R) of the structure and that the final collapse of the zeolite framework occurred through destruction of the 12-member rings (12M). This can be explained by a crystal fracture and break down process and disassembling of the sodalite cages in the faujasite structure. NH₃ microcalorimetry showed that strong acid sites in faujasites are destroyed by steam aging, but this effect does not lead to a reduction in the cracking activity of the Ecat form. The microactivity test (MAT) showed that the specific activity declined sharply at 2.430 nm UCS. Differences in product selectivity were related to the extent of damage of the zeolite, extra-framework alumina and mesoporosity. While further aging canceled the effect attributed to extra-framework alumina differences attributed to mesoporosity increased.     

Influences of the insertion method in glass ionomer cement porosity

The aim of this study was to evaluate the presence of porosities inside the glass ionomer cement (GIC) after different techniques of material insertion. MATERIAL AND METHOD: Specimens were prepared with high‐viscosity GIC Ketac Molar Easymix and divided into three groups according to the insertion method: spatula (PI), Centrix injector (CI), and low‐cost syringe (LCS). The specimens were fractured and observed with scanning electronic microscopy to quantitatively evaluate porosity inside the material using Image J Software. RESULTS: Statistical analysis, ANOVA application, and Tukey test to significance level of 5%, revealed that there was no statistical difference between the groups. CONCLUSION: Although the use of LCS has not decreased the porosity of the material, this insertion method is easy, accessible, and low cost, which makes it a viable alternative of use in the ART technique and in others bucal health programs. Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc.     

Differential Electrochemical Conductance Imaging at the Nanoscale

Electron transfer in proteins is essential in crucial biological processes. Although the fundamental aspects of biological electron transfer are well characterized, currently there are no experimental tools to determine the atomic‐scale electronic pathways in redox proteins, and thus to fully understand their outstanding efficiency and environmental adaptability. This knowledge is also required to design and optimize biomolecular electronic devices. In order to measure the local conductance of an electrode surface immersed in an electrolyte, this study builds upon the current–potential spectroscopic capacity of electrochemical scanning tunneling microscopy, by adding an alternating current modulation technique. With this setup, spatially resolved, differential electrochemical conductance images under bipotentiostatic control are recorded. Differential electrochemical conductance imaging allows visualizing the reversible oxidation of an iron electrode in borate buffer and individual azurin proteins immobilized on atomically flat gold surfaces. In particular, this method reveals submolecular regions with high conductance within the protein. The direct observation of nanoscale conduction pathways in redox proteins and complexes enables important advances in biochemistry and bionanotechnology.     

On the effect of Multiple Access Interference in a Space Time Spreading Time Hopping PPM UWB system

This study investigates the effect of multiple sources using STS across a Time-Hopping-PPM Modulation that is over an UWB Saleh-Valenzuela channel with each source using two transmit antennas. We model and analyze this system, showing that the presence of such MAI results in a significant degradation in BER performance. Simulation results show that for strong signal strength of interfering MAI signals degradation in BER performance is observed for the cases where we have five and 10 distinct MAI sources present when using Walsh-Hadamard thirty two chip spreading sequences. Using simulation, we investigate the use of other sets of orthogonal spreading sequences with improved cross correlation properties and find that for some sequences a significant improvement is seen compared to Walsh-Hadamard sequences when they are similarly misaligned. We show that MAI degrades the BER performance of such systems and that selection of improved cross correlation spreading code sequence sets improves BER.     

N‐Benzyl‐4‐((heteroaryl)methyl)benzamides: A New Class of Direct NADH‐Dependent 2‐trans Enoyl–Acyl Carrier Protein Reductase (InhA) Inhibitors with Antitubercular Activity

Isoniazid (INH) remains one of the cornerstones of antitubercular chemotherapy for drug‐sensitive strains of M. tuberculosis bacteria. However, the increasing prevalence of multidrug‐resistant (MDR) and extensively drug‐resistant (XDR) strains containing mutations in the KatG enzyme, which is responsible for the activation of INH into its antitubercular form, have rendered this drug of little or no use in many cases of drug‐resistant tuberculosis. Presented herein is a novel family of antitubercular direct NADH‐dependent 2‐trans enoyl–acyl carrier protein reductase (InhA) inhibitors based on an N‐benzyl‐4‐((heteroaryl)methyl)benzamide template; unlike INH, these do not require prior activation by KatG. Given their direct InhA target engagement, these compounds should be able to circumvent KatG‐related resistance in the clinic. The lead molecules were shown to be potent inhibitors of InhA and showed activity against M. tuberculosis bacteria. This new family of inhibitors was found to be chemically tractable, as exemplified by the facile synthesis of analogues and the establishment of structure–activity relationships. Furthermore, a co‐crystal structure of the initial hit with the enzyme is disclosed, providing valuable information toward the design of new InhA inhibitors for the treatment of MDR/XDR tuberculosis.     

Assessment of heavy metals remobilization by fractionation: comparison of leaching tests applied to roadside sediments

The pollution emitted by traffic activities and road maintenance is an area of great interest as contaminants can be transported to roadside sediments and pose a risk to environmental and human health. In the presentwork, deposited pollution in roadside sediments has been assessed by sampling along a highly traveled highway in Barcelona and the surrounding area. The available amounts of the heavy metals was determined by applying different leaching tests and calculating the concentration enrichment ratio (CER) and the environmental concentration guideline values (ECG). To gain information on the heavy metals (HMs) fractionation, the sequential extraction scheme (SES), established by the Standard Measurement and Testing (SM&T), was implemented, and the results were compared with those obtained by single leaching tests. An anthropogenic enhancement of certain metals was observed after considering both the CER and ECG values. However, if only ECG values were considered, an overestimation of the anthropogenically enhanced pollutants was obtained due to disregarding geochemical and particle size variability. CER values provide a more realistic assessment by determining different levels of anthropogenic impact. Thus, CER values suggest a minimum anthropogenic apportion for metals such as Cd, Cr, and Ni, whereas different situations from significant to extreme anthropogenic contribution were observed for Zn, Pb, and Cu. These results have been complemented by other leaching tests that minimize the time-consuming environmental evaluation. In this study, HCI extraction produces suitable results for a quick screening since they correlate well with the corresponding SES: Cu(r2 = 0.798), Pb(r2 = 0.958) and Zn(r2 = 0.901). Mild extractants have been observed to be limited to highly polluted samples due to their low leaching power. The information obtained following this procedure helps to identify hazardous areas that need a remedial strategy.     

Thermosensitive fibres of lyocell/poly(N‐isopropylacrylamide): multiparametric analysis for studying the graft copolymerization

The thermosensitive properties of the hydrogel poly(N‐isopropylacrylamide) (pNIPAAm) together with the good mechanical properties of lyocell fibres make a combination of the two to be thought of as a smart textile. In the present study the optimal values of various parameters that control the grafting process of pNIPAAm onto lyocell fibres were determined considering the influence of the interaction between them. The copolymerization of pNIPAAm hydrogel onto lyocell fibres was performed in aqueous acidic medium using cerium(IV) as initiator. An experimental design was planned in order to study the effect of the interactions between some variables that affect the kinetics of the graft copolymerization: the cerium(IV) initiator concentration, the N‐isopropylacrylamide (NIPAAm) monomer concentration and the liquor fibre‐to‐bath ratio. The results show that the interaction between the concentrations of NIPAAm and the initiator significantly affects the degree of grafting (DG), the optimum values being 1250 and 12.25 mmol L^?1, respectively. In contrast, the liquor ratio parameter shows no significant interaction with the other two variables studied, meaning that it acts independently but showing a proportional relationship with respect to the DG obtained. In addition, the presence of pNIPAAm in the copolymer obtained was confirmed by Fourier transform infrared spectral analysis. Moreover, the water sorption capacity, depending on the temperature, of the lyocell/pNIPAAm copolymer was studied, with an increase being observed when the DG is higher than 60% and also increasing with the temperature.© 2012 Society of Chemical Industry