Microwave-Assisted Extraction of Brewers' Spent Grain Arabinoxylans

Brewers´ spent grain (BSG) is a by-product from beer industry that can be exploited as a source of arabinoxylo-oligosaccharides (AXOS) with prebiotic activity. In this study, microwave-assisted extractions were performed during 2 min at 140-210°Cin order to evaluate the feasibility of this extraction technology for quantitative extraction of the arabinoxylans (AX) or AXOS from BSG. The AX yield increasedwith the increase of the temperature in the range used. The best condition of extraction of the AXwas 210 ºC during 2 min, allowing the extraction of 43% of total AX. These AX showed structural variability which allow to define specific types of compounds for different applications and uses depending on the extraction conditions used

Theory of one and two donors in Silicon

We provide here a roadmap for modeling silicon nano-devices with one or two group V donors (D). We discuss systems containing one or two electrons, that is, D^0, D^-, D_2^+ and D_2^0 centers. The impact of different levels of approximation is discussed. The most accurate instances -- for which we provide quantitative results -- are within multivalley effective mass including the central cell correction and a configuration interaction account of the electron-electron correlations. We also derive insightful, yet less accurate, analytical approximations and discuss their validity and limitations -- in particular, for a donor pair, we discuss the single orbital LCAO method, the Huckel approximation and the Hubbard model. Finally we discuss the connection between these results and recent experiments on few dopant devices.Comment: 13 pages, 6 figure

Impact of the valley degree of freedom on the control of donor electrons near a Si/SiO_2 interface

We analyze the valley composition of one electron bound to a shallow donor close to a Si/barrier interface as a function of an applied electric field. A full six-valley effective mass model Hamiltonian is adopted. For low fields, the electron ground state is essentially confined at the donor. At high fields the ground state is such that the electron is drawn to the interface, leaving the donor practically ionized. Valley splitting at the interface occurs due to the valley-orbit coupling, V_vo^I = |V_vo^I| e^{i theta}. At intermediate electric fields, close to a characteristic shuttling field, the electron states may constitute hybridized states with valley compositions different from the donor and the interface ground states. The full spectrum of energy levels shows crossings and anti-crossings as the field varies. The degree of level repulsion, thus the width of the anti-crossing gap, depends on the relative valley compositions, which vary with |V_vo^I|, theta and the interface-donor distance. We focus on the valley configurations of the states involved in the donor-interface tunneling process, given by the anti-crossing of the three lowest eigenstates. A sequence of two anti-crossings takes place and the complex phase theta affects the symmetries of the eigenstates and level anti-crossing gaps. We discuss the implications of our results on the practical manipulation of donor electrons in Si nanostructures.Comment: 8 pages, including 5 figures. v2: Minor clarifying changes in the text and figures. Change of title. As published in PR

Watermelon stomach seen by wireless‐capsule endoscopy

Endoscopy. 2003 Jan;35(1):100. Watermelon stomach seen by wireless-capsule endoscopy. Mascarenhas-Saraiva M, Lopes L, Mascarenhas-Saraiva A. SourceDigestive Endoscopy and Motility Unit, Trindade Hospital, Rua Trinidade 115, 4000-541 Porto, Portugal. [email protected] PMID:12510242[PubMed - indexed for MEDLINE

Research on quality management and sustainability

Purpose - This article aims to ascertain the necessity for specific research on quality management approaches, bringing to the discussion some concerns and challenges to the quality movement, especially in development of new methodologies for supporting design in the digital area. Design/methodology/approach - Firstly, papers were researched that had already studied the question of what research should carry out in response to the great scientific, technical, and social changes, specifically to support design activities for internet products and secondly we concluded what development is needed. Findings - The increasing complexity of management and technology creates many situations of anxiety and distress, which often translate into abandonment of proven techniques and methodologies, leading to intuitive approaches. But complexity requires more techniques and methodologies not less. The quality movement faces a serious challenge: how to design in an ethical perspective these types of products. Research limitations/implications - This research is limited to identify some needs, but future research should be done in characterizing existing answers and identifying what development is needed. Practical implications - The above findings and reflections can help other researchers to focus on design, to find out practical solutions for sustainability in the innovation process of products and services. Social implications - Finding out to design in an ethical perspective products and services for internet. Originality/value - This research identified relevant challenges the quality management is facing, and it gives guidelines for defining research lines.info:eu-repo/semantics/publishedVersio

Effect of Water Content on the Thermal Inactivation Kinetics of Horseradish Peroxidase Freeze-Dried from Alkaline pH

The thermal inactivation of horseradish peroxidase freeze-dried from solutions of different pH (8, 10 and 11.5, measured at 25 C) and equilibrated to different water contents was studied in the temperature range from 110 to 150 C. The water contents studied (0.0, 1.4, 16.2 and 25.6 g water per 100 g of dry enzyme) corresponded to water activities of 0.0, 0.11, 0.76 and 0.88 at 4 C. The kinetics were well described by a double exponential model. The enzyme was generally more stable the lower the pH of the original solution, and for all pH values, the maximum stability was obtained at 1.4 g water/100 g dry enzyme. Values of z were generally independent of water content and of the pH of the original solution, and in the range of 15–25 °C, usually found in neutral conditions, with the exception of the enzyme freeze dried from pH 11.5 and equilibrated with phosphorus pentoxide, where a z-value of the stable fraction close to 10 C was found

Implementation of quality management systems in HEI: The approach of the Polytechnic Institute of Setubal (Portugal)

Higher Education Institutions (HEI) have special features that matter to consider in the implementation of its Quality Management Systems (QMS). These should convey clear and broadly accepted messages, so they need to find the best balance between academic freedom and responsibility for accountability. Given these characteristics, as well as the weakness of diagnostic tools, the culture of independence of teachers and insufficient authority and stability of the management bodies, the QMS of the Polytechnic Institute of Setúbal (IPS) was designed to be based on two fundamental pillars: profound knowledge of the variables with impact on results and evidence-based management. In other words, it was not based on procedures (as usual), but in information. In this sense, and assuming known statement that “we cannot manage what we do not know”, the basic component of the QMS is a monitoring system. We applied the recommendation of Snyder et al. (2000, p.320) "Stimulating the imbalance with information", urging people to act on the basis of clear information. The work undertaken till now (last five years) is described and discussed critically. This work includes, among other activities and projects, the design of a Global Model Process, the design of the organizational structure of IPS’s Integrated Management System (SIGIPS), and the definition of the institutional Quality Policy. In addition, and assuming QMS as multidisciplinary fields, it has also been stepping up the contribution of Research and Development (R&D) activities of some teachers, combined with the needs of scientific and technical support related to the implementation of the system itself. It is in this context that SIGIPS’s central coordination unit (UNIQUA/IPS), whose constitution also includes a Studies and Planning Center, has been operating a set of complementary studies in priority areas, particularly with regard to the teaching and learning process. Examples of this are the (annual) reports of socio demographic characterization of students and the studies about the evaluation of the implementation of Bologna process in the context of the institution and about issues of academic success/failure and dropout. The main findings are presented, namely the reduction of the administrative and burocratic work, the increase of management support and the availability of updated and relevant information, reinforcing the management style based on facts. The initiatives have always had technical and scientific support, gathering support and credibility to QMS. The top structure of the QMS is innovative, balancing academic knowledge and the application of quality techniques and methods to HEI, contributing to a structure of practical research. The questionnaires for assessing student perceptions were discussed and it was concluded that traditionally they are "too reactive" (applied in end of semesters), which means that other diagnostic instruments (proactive and dynamic) are necessary. This situation has, therefore, reinforce the need to use instruments nearer to the "problem situation" in regard to the teaching learning process, which would contribute to more effective process improvement and could even involve the participation of students or be managed by them. Finally, an adequate Information System based on the Information and Communication Technologies is definitely an indispensable resource.info:eu-repo/semantics/publishedVersio

Measurement of a superficial texture by applying the alpha parameter on the profile P, for measuring a manual transmission gear

The objective of this work is to demonstrate the P Profile application in the measurement of superficial texture of the cone seat of the synchronization ring gear of a Mechanical Transmission. It is known that this superficial texture is an essential factor for the good performance and durability of a Mechanical Transmission, since the variation of this texture is directly linked to the synchronization failure, premature wear of the synchronization ring coupling guides, gear and sleeve