José Teixeira

Reforming scholarly publishing and knowledge communication: From the advent of the scholarly journal to the challenges of open access

Purpose – The purpose of this paper is to provide an overview of the continuous evolution of scholarly publishing and knowledge communication as a result of the internet revolution.Design/methodology/approach – Information was obtained from a literature review of the main contributions on “self‐archiving” – the broad term often applied to electronic publishing of author‐supplied documents on the web without commercial publisher mediation. The paper analyses the impact of the open access movement, which came to fruition after the OAI Metadata Harvesting Protocol was established, as it creates the potential for interoperability between e‐print repositories. It concludes by outlining the challenges for information managers in developing the full potential of open access.Findings – With regard to the future of self‐archiving, particularly in relation to peer‐reviewed journals, information managers have a very important role to perform within their organization.Originality/value – The paper highlights the bene...

Advanced interaction techniques in virtual environments

Abstract Fundamental to much of the Virtual Reality work is, in addition to high-level 3D graphical and multimedia scenes, research on advanced methods of interaction. The “visitor” of such virtual worlds must be able to act and behave intuitively, as he would in everyday situations, as well as receive expectable natural behaviour presented as feedback from the objects in the environment, in a way that he/she has the feeling of direct interaction with his/her application. In this paper we present several techniques to enrich the naturalness and enhance the user involvement in the virtual environment. We present how the user is enabled to grab objects without using any specific and elaborate hand gesture, which is more intuitive and close to the way humans are used to do. We also introduce a technique that makes it possible for the user to surround objects without any force-feedback interaction device. This technique allows the user to surround or “walk” with the virtual hand on the objects surface and look for the best position to grab it.

Form feature modelling in a hybrid CSG/BRep scheme

Abstract A new hybrid pseudo-CSG/BRep schema for product modelling is described. In this schema, there exists a clear distinction between morphology and the geometry of an object. At the highest level of abstraction, the object morphology or shape is hierarchically defined by means of a graph, called Feature Adjacency Graph (FAG), in which the nodes are either positive or negative volumetric cells (form features) and the arcs are adjacency/interaction relationships between those cells. The hierarchical morphological characterization of an object made by the FAG allows to one decrease or even suppress the semantic gap between the product model and the underlying solid model since each cell always embodies a form feature. In this manner it becomes possible to capture the designer intent, as well as to help the CAD/CAM integration. At the low level of abstraction, i.e., the BRep level, two associated data structures are maintained. The first, called Feature Topological Structure (FTS), holds the family of volumetric cells, each one of them represented explicitly by its surface boundary (BRep). The second constitutes the evaluated BRep model itself for the object solid. It should be noted that any constructive or destructive compositional action in the object definition occurs simultaneously in both data structures. In a way, the FTS retains at a low level, the construction history of the object model. Besides, the availability of the topological entities belonging to the BRep allows a graphical dialog with the model and also facilitates the generation of instructions for NC milling machines. In short, this hybrid pseudo-CSG/BRep intends to capture the virtues of both representation schemas and eliminate as much as possible as their underlying drawbacks.

A Cellular Approach for Feature-Based Modeling

The main goal of this paper is to present a new cellular scheme for feature-based modeling and to show its applicability. With this cellular scheme it becomes possible to distinguish, clearly, and completely, between the morphology and the geometry of a solid. An object is globally and morphologically defined by a collection of interacting form features. Moreover, a form feature is defined as a structured cluster of one or more volumetric cells. As it will be shown, this conceptual scheme facilitates reasoning strategies, at the cellular level, fired from constructive and destructive morphological actions taken at the feature level.

Reforming scholarly publishing and knowledge communication: From the advent of the scholarly journal to the challenges of Open Access

This paper provides an overview of the continuing evolution of scholarly publishing, leveraged in the last decades by the tremendous potential of Internet technology. It introduces “self-archiving”, the broad term often applied to the electronic publishing of author-supplied documents on the World Wide Web without commercial publisher mediation, and examines its impact on scholarly communication along with the Open Access Movement. The intensity of self-archiving and its pivotal role in scholarly communication is put into perspective through reference to some self-archiving initiatives set in motion in several countries. Finally, the paper concludes by outlining the challenges for information managers in developing the full potential of Open Access.

Development of hydroxybenzoic-based platforms as a solution to deliver dietary antioxidants to mitochondria

Oxidative stress and mitochondrial dysfunction have been associated with metabolic and age-related diseases. Thus, the prevention of mitochondrial oxidative damage is nowadays a recognized pharmacological strategy to delay disease progression. Epidemiological studies suggested an association between the consumption of polyphenol-rich diet and the prevention of different pathologies, including diseases with a mitochondrial etiology. The development of mitochondrial-targeted antioxidants based on dietary antioxidants may decrease mitochondrial oxidative damage. Herein, we report the design and synthesis of two new mitochondriotropic antioxidants based on hydroxybenzoic acids (AntiOxBENs). The results obtained showed that the novel antioxidants are accumulated inside rat liver mitochondria driven by the organelle transmembrane electric potential and prevented lipid peroxidation, exhibiting low toxicity. Some of the observed effects on mitochondrial bioenergetics resulted from an increase of proton leakage through the mitochondrial inner membrane. The new derivatives present a higher lipophilicity than the parent compounds (protocatechuic and gallic acids) and similar antioxidant and iron chelating properties. AntiOxBENs are valid mitochondriotropic antioxidant prototypes, which can be optimized and used in a next future as drug candidates to prevent or slow mitochondrial oxidative stress associated to several pathologies.

Intelligent form feature interaction management in a cellular modeling scheme

Form features present a rather attractive building block in computer-aided design environments for a variety of applications, providing the embodiment of engineering semantics in specific part shape. In this paper we address the issue of volume feature behaviour throughout interaction phenomena. First, the fundamental concept of form feature as expression of the morphology of a model, is presented. A description of the feature properties, attributes and general constraints that are relevant for our purpose is attempted. In order to develop sound validity conditions for the various classes of form features, feature definitional entities are also introduced. A comprehensive definition of interaction among features is given that encompasses both adjacent and intersecting features. We use a structured cellular modeling scheme to capture both the morphology of features and the interactions among them. Within this framework, a thorough analysis of feature interactions is performed that explores the accessibility of feature definitional entities in order to assist feature-based model editing and validation. Operations that create or modify features often interfere with pre-existing ones, producing unanticipated effects that can corrupt or, at least, modify desired feature semantics and/or morphology. On the other hand, valid features can be obtained that exhibit non-standard or disconnected topology as a result of interactions caused by such operations. Systematic management of feature interactions is explored in both cases, from an object-oriented point of view, encapsulating interaction detection methods in feature class definition. This approach is shown to be quite adequate to handle complex interactions among several features. Reasoning mechanisms may, thereafter, be required to handle each situation identified.

Precise Object Interactions using Solid Modeling Techniques

The great potential provided by the existing 3D hardware and software provide us the tools for modeling and displaying complete 3D physical objects in computer systems. Despite the advanced ability to create and display 3D objects, there is a lack of interaction techniques by which the user can intuitively manipulate these 3D objects and perceive information about them.

Storage Support for Multidimensional Discrete Data in Multimedia Databases

Multidimensional discrete data (MDD) is enormously important for multimedia applications since diverse types of such data are used simultaneously by any multimedia application. However, multidimensional discrete data is not adequately supported by most existing database systems.

Extracellular acidification induces ROS- and mPTP-mediated death in HEK293 cells

The extracellular pH (pHe) is a key determinant of the cellular (micro)environment and needs to be maintained within strict boundaries to allow normal cell function. Here we used HEK293 cells to study the effects of pHe acidification (24 h), induced by mitochondrial inhibitors (rotenone, antimycin A) and/or extracellular HCl addition. Lowering pHe from 7.2 to 5.8 reduced cell viability by 70% and was paralleled by a decrease in cytosolic pH (pHc), hyperpolarization of the mitochondrial membrane potential (Δψ), increased levels of hydroethidine-oxidizing ROS and stimulation of protein carbonylation. Co-treatment with the antioxidant α-tocopherol, the mitochondrial permeability transition pore (mPTP) desensitizer cyclosporin A and Necrostatin-1, a combined inhibitor of Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and Indoleamine 2,3-dioxygenase (IDO), prevented acidification-induced cell death. In contrast, the caspase inhibitor zVAD.fmk and the ferroptosis inhibitor Ferrostatin-1 were ineffective. We conclude that extracellular acidification induces necroptotic cell death in HEK293 cells and that the latter involves intracellular acidification, mitochondrial functional impairment, increased ROS levels, mPTP opening and protein carbonylation. These findings suggest that acidosis of the extracellular environment (as observed in mitochondrial disorders, ischemia, acute inflammation and cancer) can induce cell death via a ROS- and mPTP opening-mediated pathogenic mechanism.