A.C. Baptista

Thin and flexible bio-batteries made of electrospun cellulose-based membranes

The present work proposes the development of a bio-battery composed by an ultrathin monolithic structure of an electrospun cellulose acetate membrane, over which was deposited metallic thin film electrodes by thermal evaporation on both surfaces. The electrochemical characterization of the bio-batteries was performed under simulated body fluids like sweat and blood plasma [salt solution--0.9% (w/w) NaCl]. Reversible electrochemical reactions were detected through the cellulose acetate structure. Thus, a stable electrochemical behavior was achieved for a bio-battery with silver and aluminum thin films as electrodes. This device exhibits the ability to supply a power density higher than 3 μW cm(-2). Finally, a bio-battery prototype was tested on a sweated skin, demonstrating the potential of applicability of this bio-device as a micropower source.

Cellulose-Based Bioelectronic Devices

The integration of biomolecules with electronic elements to form multifunctional devices has been recently the subject of intense scientific research. The need of new sensors exhibiting a high selectivity and a total reliability in connection with smart systems and actuators for real time diagnostic and monitoring of diseases has driven wonderful developments in sensors and particularly in biosensors. Biosensors can be regarded as complementary tools to classical analytical methods due to their inherent simplicity, relative low cost, rapid response and proneness to miniaturization, thereby allowing continuous monitoring. They can integrate portable and implantable devices and be used in biological and biomedical systems. However, the development of biocompatible, nontoxic and lightweight power sources devices is still challenging. It would enable the production of various functional devices mechanically flexible and auto-sustained, allowing their integration into a wide range of innovative products such as in implantable medical devices.

A complex case of hepatitis in a patient with systemic lupus erythematosus.

Abstract: Liver involvement in patients with systemic lupus erythematosus (SLE) is considered rare. Previous treatment with potentially hepatotoxic drugs or viral hepatitis have usually been implicated as the main causes of liver disease in SLE patients. On the other hand, even after careful exclusion of these aetiologies, the problem remains whether to classify the patient as having a primary liver disease with associated autoimmune clinical and laboratory features resembling SLE, such as autoimmune hepatitis, or as having liver disease as a manifestation of SLE.  We report the case of an elderly woman who presented with acute hepatitis, who had been diagnosed with SLE 14 years ago and who also had Sjo¨gren’s syndrome and anti-phospholipid’s syndrome for several years. The histology depicted chronic active hepatitis and, after drug-induced hepatitis and viral hepatitis were excluded, the serological and clinical features were shown to be typical of liver damage caused by SLE. The patient was treated with azathioprine 100mg/d and prednisone 30 mg/d. The clinical symptoms resolved in 10 days and the laboratory values were normal at the end of the first month of therapy. Prednisone was progressively reduced, during a period of 4 months, to 10 mg/d but azathioprine was kept to the same dose. One year after the diagnoses the patient is still in remission.  Although uncommon, hepatic involvement is well recognised in SLE. The interest of this case lies in the differential diagnosis and recognition of this condition, which deserves an agressive treatment.

Electrospun Fibers in Composite Materials for Medical Applications

Sem PDF conforme Despacho. The authors acknowledge Portuguese Science and Technology Foundation (FCT-MCTES) for the financial support through the Strategic Project PEstC/CTM/LA0025/2013-14. Ana C. Baptista also acknowledges FCT-MCTES for the doctoral grant SFRH/BD/69306/2010.

Cellulose-based electrospun fibers functionalized with polypyrrole and polyaniline for fully organic batteries

A novel cellulose-based bio-battery made of electrospun fibers activated by biological fluids has been developed. This work reports a new concept for a fully organic bio-battery that takes advantage of the high surface to volume ratio achieved by an electrospun matrix composed of sub-micrometric fibers that acts simultaneously as the separator and the support of the electrodes. Polymer composites of polypyrrole (PPy) and polyaniline (PANI) with cellulose acetate (CA) electrospun matrix were produced by in situ chemical oxidation of pyrrole and aniline on the CA fibers. The structure (CA/PPy|CA|CA/PANI) generated a power density of 1.7 mW g−1 in the presence of simulated biological fluids, which is a new and significant contribution to the domain of medical batteries and fully organic devices for biomedical applications.

Web accessibility challenges and perspectives: A systematic literature review

With this paper we intend to present a systematic literature review on Web accessibility. During this research project, 782 papers were identified and by following a set of inclusion criteria, 38 stood out and were extensively analyzed. On this context we approach a set of Web accessibility critical issues, such as: guidelines, standards and regulations; mobile accessibility; organizations and user perspectives on the topic. During the full scope of this document we adopt a positive position, always focused on presenting solutions to ensure websites accessibility.

Natural Nanofibres for Composite Applications

Cellulose and chitin are the two most abundant natural polysaccharides. Both have a semicrystalline microfibrillar structure from which nanofibres can be extracted. These nanofibres are rod-like microcrystals that can be used as nanoscale reinforcements in composites due to their outstanding mechanical properties. This chapter starts by reviewing the sources, extraction methods and properties of cellulose and chitin nanofibres. Then, their use in the fabrication of structural and functional nanocomposites and the applications that have been investigated are reviewed. Nanocomposites are materials with internal nano-sized structures. They benefit from the properties of the nanofillers: low density, nonabrasive, nontoxic, low cost, susceptibility to chemical modifications and biodegradability. Diverse manufacturing technologies have been used to produce films, fibres, foams, sponges, aerogels, etc. Given their natural origin and high stiffness, these polymers have attracted a lot of attention not only in the biomedical and tissue engineering fields but also in areas such as pharmaceutics, cosmetics, agriculture, biosensors and water treatment.

Hybrid polysaccharide-based systems for biomedical applications

Abstract Hybrid materials have been widely studied for structural applications. Polysaccharide-based fibers, especially cellulosic fibers, have been explored in the last two decades as substitutes of the traditional reinforcements made of glass or carbon fibers due to their mechanical properties. However, their biocompatibility, biodegradability, and chemistry have attracted the researchers and new developments in the field of smart and functional materials arise in diverse applications. This chapter will focus on the biomedical applications of polysaccharide-based smart and functional materials, namely those concerning biosensors and actuators, theranostic systems, and tissue-engineering applications. Special attention will be given to cellulose- and chitin/chitosan-based hybrid materials because these are the two most abundant polysaccharides and probably the most promising for the development of hybrid materials for biomedical applications. Biomimetic strategies for the development of smart and functional hybrid materials will also be highlighted.

Computer Supported Cooperative Work—Exploratory Study on CSCW and Groupware Technologies and its Applicability in the Health Area

Since the dawn of human civilization that cooperation among individuals is observed. In the most primitive stage this phenomenon was manifested through hunting groups, progressing to the construction of objects and buildings and in a later phase in the construction of modern society itself. Nowadays with the advent of technology and rise of ICT, collaborative processes across workgroups in organizations have been increasingly supported by this concept. The use of technology for supporting collaborative processes of working groups led to the creation of areas of study as CSCW and Groupware. In the health area, collaborative platforms have been used for supporting medical distance learning, social networks for collaboration, patient monitoring, discussion forums and sharing of medical media content. This paper has the goal of analyzing technological advances and the application of collaborative platforms in the health area, through an exploratory work of literature and application analysis and discussion.