Maria Cristina Ferreira de Oliveira

A statechart-based model for hypermedia applications

This paper presents a formal definition for HMBS (Hypermedia Model Based on Statecharts). HMBS uses the structure and execution semantics of statecharts to specify both the structural organization and the browsing semantics of hypermedia applications. Statecharts are an extension of finite-state machines and the model is thus a generalization of hypergraph-based hypertext models. Some of the most important features of HMBS are its ability to model hierarchy and synchronization of information; provision of mechanisms for specifying access structures, navigational contexts, access control, multiple tailored versions,and hierarchical views. Analysis of the underlying statechart machine allows verification of page reachability, valid paths, and other properties, thus providing mechanisms to support authors in the development of structured applications.

The Projection Explorer: A Flexible Tool for Projection-based Multidimensional Visualization

This paper presents a new approach to multiple objects tracking that combines particle filters and k-means. The approach has been tested under an important real world situation, related to pharmacological development, which has also proved to serve as an interesting ground-truth dataset provider for the evaluation of tracking algorithms. The obtained results are then compared to other models. The promising results of these experiments are presented.

A navigation-oriented hypertext model based on statecharts

In this paper we present a navigation-oriented model for hyperdocument specification based on statecharts. The HMBS (Hypertext Model Based on Statecharts) model uses the structure and execution semantics of statecharts to specify both the structural organization and the browsing semantics of a hyperdocument. The formal definition of the model is presented, as well as its associated browsing semantics. A short discussion on the model’s capabilities is also provided. A prototype hypertext system which implements HMBS as its underlying model for hyperdocument authoring and browsing is introduced, and some examples are presented that illustrate the application of the model.

Seeing beyond reading: a survey on visual text analytics

We review recent visualization techniques aimed at supporting tasks that require the analysis of text documents, from approaches targeted at visually summarizing the relevant content of a single document to those aimed at assisting exploratory investigation of whole collections of documents.Techniques are organized considering their target input material—either single texts or collections of texts—and their focus, which may be at displaying content, emphasizing relevant relationships, highlighting the temporal evolution of a document or collection, or helping users to handle results from a query posed to a search engine.We describe the approaches adopted by distinct techniques and briefly review the strategies they employ to obtain meaningful text models, discuss how they extract the information required to produce representative visualizations, the tasks they intend to support and the interaction issues involved, and strengths and limitations. Finally, we show a summary of techniques, highlighting their goals and distinguishing characteristics. We also briefly discuss some open problems and research directions in the fields of visual text mining and text analytics.

Use of Information Visualization Methods Eliminating Cross Talk in Multiple Sensing Units Investigated for a Light-Addressable Potentiometric Sensor

The integration of nanostructured films containing biomolecules and silicon-based technologies is a promising direction for reaching miniaturized biosensors that exhibit high sensitivity and selectivity. A challenge, however, is to avoid cross talk among sensing units in an array with multiple sensors located on a small area. In this letter, we describe an array of 16 sensing units of a light-addressable potentiometric sensor (LAPS), which was made with layer-by-layer (LbL) films of a poly(amidomine) dendrimer (PAMAM) and single-walled carbon nanotubes (SWNTs), coated with a layer of the enzyme penicillinase. A visual inspection of the data from constant-current measurements with liquid samples containing distinct concentrations of penicillin, glucose, or a buffer indicated a possible cross talk between units that contained penicillinase and those that did not. With the use of multidimensional data projection techniques, normally employed in information visualization methods, we managed to distinguish the results from the modified LAPS, even in cases where the units were adjacent to each other. Furthermore, the plots generated with the interactive document map (IDMAP) projection technique enabled the distinction of the different concentrations of penicillin, from 5 mmol L(-1) down to 0.5 mmol L(-1). Data visualization also confirmed the enhanced performance of the sensing units containing carbon nanotubes, consistent with the analysis of results for LAPS sensors. The use of visual analytics, as with projection methods, may be essential to handle a large amount of data generated in multiple sensor arrays to achieve high performance in miniaturized systems.

Autologous hematopoietic stem cell transplantation for type 1 diabetes.

In this review, we present (1) the scientific basis for the use of high‐dose immunosuppression followed by autologous peripheral blood hematopoietic stem cell transplantation for newly diagnosed type 1 diabetes (T1D); (2) an update of the clinical and laboratory outcome of 20 patients transplanted at the University Hospital of the Ribeirão Preto Medical School, University of São Paulo, Brazil, and followed up to January/2008, including 4 relapses among 19 patients without previous ketoacidosis; (3) a commentary on criticisms to our article that appeared in four articles from the scientific literature; and (4) a discussion of the prospectives for cellular therapy for T1D.

XHMBS: a formal model to support hypermedia specification

This paper introduces XHMBS (the extended Hyperdocument Model Based on Statecharts) to support the formal specification of general hypermedia applications. XHMBS uses a novel formalism called hypercharts as its underlying model for specifying the navigational structure, browsing semantics and synchronization requirements of a hyperdocument. Hypercharts are statecharts extended with additional mechanisms for describing the time sequencing and information synchronization requirements typical of multimedia. The extensions incorporated into hypercharts are based on the major characteristics of some Petri net based multimedia models, and make it an alternative to such models for multimedia and hypermedia specification. XHMBS provides facilities for defining the structure of a hypermedia application in terms of nodes and links and also for describing the temporal behavior of dynamic data streams contained in nodes. The model incorporates presentation and communication channels for describing spatial coordination and distribution of information, and anchor objects for ensuring separation between information structure and content.

Immunological Balance Is Associated with Clinical Outcome after Autologous Hematopoietic Stem Cell Transplantation in Type 1 Diabetes

Autologous hematopoietic stem cell transplantation (AHSCT) increases C-peptide levels and induces insulin independence in patients with type 1 diabetes. This study aimed to investigate how clinical outcomes may associate with the immunological status, especially concerning the balance between immunoregulation and autoreactivity. Twenty-one type 1 diabetes patients were monitored after AHSCT and assessed every 6 months for duration of insulin independence, C-peptide levels, frequencies of islet-specific autoreactive CD8+ T cells (CTL), regulatory lymphocyte subsets, thymic function, and T-cell repertoire diversity. In median follow-up of 78 (range 15–106) months, all patients became insulin-independent, resuming insulin after median of 43 (range 6–100) months. Patients were retrospectively divided into short- or prolonged-remission groups, according to duration of insulin independence. For the entire follow-up, CD3+CD4+ T-cell numbers remained lower than baseline in both groups, whereas CD3+CD8+ T-cell levels did not change, resulting in a CD4/CD8 ratio inversion. Memory CTL comprehended most of T cells detected on long-term follow-up of patients after AHSCT. B cells reconstituted to baseline levels at 2–3 months post-AHSCT in both patient groups. In the prolonged-remission-group, baseline islet-specific T-cell autoreactivity persisted after transplantation, but regulatory T cell counts increased. Patients with lower frequencies of autoreactive islet-specific T cells remained insulin-free longer and presented greater C-peptide levels than those with lower frequencies of these cells. Therefore, immune monitoring identified a subgroup of patients with superior clinical outcome of AHSCT. Our study shows that improved immunoregulation may balance autoreactivity endorsing better metabolic outcomes in patients with lower frequencies of islet-specific T cells. Development of new strategies of AHSCT is necessary to increase frequency and function of T and B regulatory cells and decrease efficiently autoreactive islet-specific T and B memory cells in type 1 diabetes patients undergoing transplantation.

Information Visualization to Enhance Sensitivity and Selectivity in Biosensing

An overview is provided of the various methods for analyzing biosensing data, with emphasis on information visualization approaches such as multidimensional projection techniques. Emphasis is placed on the importance of data analysis methods, with a description of traditional techniques, including the advantages and limitations of linear and non-linear methods to generate layouts that emphasize similarity/dissimilarity relationships among data instances. Particularly important are recent methods that allow processing high-dimensional data, thus taking full advantage of the capabilities of modern equipment. In this area, now referred to as e-science, the choice of appropriate data analysis methods is crucial to enhance the sensitivity and selectivity of sensors and biosensors. Two types of systems deserving attention in this context are electronic noses and electronic tongues, which are made of sensor arrays whose electrical or electrochemical responses are combined to provide “finger print” information for aromas and tastes. Examples will also be given of unprecedented detection of tropical diseases, made possible with the use of multidimensional projection techniques. Furthermore, ways of using these techniques along with other information visualization methods to optimize biosensors will be discussed.

Strategies to Optimize Biosensors Based on Impedance Spectroscopy to Detect Phytic Acid Using Layer-by-Layer Films

Impedance spectroscopy has been proven a powerful tool for reaching high sensitivity in sensor arrays made with nanostructured films in the so-called electronic tongue systems, whose distinguishing ability may be enhanced with sensing units capable of molecular recognition. In this study we show that for optimized sensors and biosensors the dielectric relaxation processes involved in impedance measurements should also be considered, in addition to an adequate choice of sensing materials. We used sensing units made from layer-by-layer (LbL) films with alternating layers of the polyeletrolytes, poly(allylamine) hydrochloride (PAH) and poly(vinyl sulfonate) (PVS), or LbL films of PAH alternated with layers of the enzyme phytase, all adsorbed on gold interdigitate electrodes. Surprisingly, the detection of phytic acid was as effective in the PVS/PAH sensing system as with the PAH/phytase system, in spite of the specific interactions of the latter. This was attributed to the dependence of the relaxation processes on nonspecific interactions such as electrostatic cross-linking and possibly on the distinct film architecture as the phytase layers were found to grow as columns on the LbL film, in contrast to the molecularly thin PAH/PVS films. Using projection techniques, we were able to detect phytic acid at the micromolar level with either of the sensing units in a data analysis procedure that allows for further optimization.