Biofunctionalization of titanium surfaces for dental implants: osteogenic, anti-microbial and tribocorrosion resistant surfaces

PhD thesis in Biomedical Engineering

General and mental health of poor and multiproblematic families

The main feature of the so called multiproblem families is the persistence along time of a set of problems in various areas of the individual’s functioning in several family members.This research study aims: a) To identify and characterise the major health problems faced by the members of these families; b) To explore the perceived relevance of these problems; c) To explore the perceived effectiveness of health care interventions received by respondents; d) To explore the level of control perceived over these problems.

Inkjet printing technology for flexible pressure sensors

Tese de Doutoramento Ciência e Engenharia de Polímeros e Compósitos.

Cylindrically symmetric models of gravitational collapse to black holes: a short review

We survey results about exact cylindrically symmetric models of gravitational collapse in General Relativity. We focus on models which result from the matching of two spacetimes having collapsing interiors which develop trapped surfaces and vacuum exteriors containing gravitational waves. We collect some theorems from the literature which help to decide a priori about eventual spacetime matchings. We revise, in more detail, some toy models which include some of the main mathematical and physical issues that arise in this context, and compute the gravitational energy flux through the matching boundary of a particular collapsing region. Along the way, we point out several interesting open problems.

Light responsive multilayer surfaces with controlled spatial extinction capability

Multilayer systems obtained using the Layer-by-Layer (LbL) technology have been proposed for a variety of biomedical applications in tissue engineering and regenerative medicine. LbL assembly is a simple and highly versatile method to modify surfaces and fabricate robust and highly-ordered nanostructured coatings over almost any type of substrates and with a wide range of substances. The incorporation of polyoxometalate (POM) inorganic salts as constituents of the layers presents a possibility of promoting light-stimuli responses in LbL substrates. We propose the design of a biocompatible photo-responsive multilayer system based on a Preyssler-type POM ([NaP5W30O110]14â ) and a natural origin polymer, chitosan, using the LbL methodology. The photo-reduction properties of the POM allow the spatially controlled disruption of the assembled layers due to the weakening of the electrostatic interactions between the layers. This system has found applicability in detaching devices, such as the cell sheet technology, which may solve the drawbacks actually found in other cell treatment proposals.

PEGylated ofloxacin nanoparticles render strong antibacterial activity against many clinically important human pathogens.

The rise of bacterial resistance against important drugs threatens their clinical utility. Fluoroquinones, one of the most important classes of contemporary antibiotics has also reported to suffer bacterial resistance. Since the general mechanism of bacterial resistance against fluoroquinone antibiotics (e.g. ofloxacin) consists of target mutations resulting in reduced membrane permeability and increased efflux by the bacteria, strategies that could increase bacterial uptake and reduce efflux of the drug would provide effective treatment. In the present study, we have compared the efficiencies of ofloxacin delivered in the form of free drug (OFX) and as nanoparticles on bacterial uptake and antibacterial activity. Although both poly(lactic-co-glycolic acid) (OFX-PLGA) and methoxy poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) (OFX-mPEG-PLGA) nanoformulations presented improved bacterial uptake and antibacterial activity against all the tested human bacterial pathogens, namely, Escherichia coli, Proteus vulgaris, Salmonella typhimurium, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus, OFX-mPEG-PLGA showed significantly higher bacterial uptake and antibacterial activity compared to OFX-PLGA. We have also found that mPEG-PLGA nanoencapsulation could significantly inhibit Bacillus subtilis resistance development against OFX.

Biomimetic superhydrophobic surfaces patterned with wettable spots as implantable chips for in vivo high-content 3D biomaterials response assessment

"Tissue engineering: part A", vol. 21, suppl. 1 (2015)

Can the dopaminergic-related effects of general anesthetics be linked to mechanisms involved in drug abuse and addiction?

BACKGROUND: General anesthetics (GA) are well known for the ability to induce a state of reversible loss of consciousness and unresponsiveness to painful stimuli. However, evidence from animal models and clinical studies show that GA exposure may induce behavioral changes beyond acute effects. Most research and concerns are focused on changes in cognition and memory. METHODS: We will look at effects of GA on behavior that is mediated by the dopaminergic system. RESULTS: Pharmacological resemblance of GA with drugs of abuse, and the complexity and importance of dopaminergic systems in both reward seeking and addictive illnesses make us believe that it deserves an overview about what is already known and what matters to us as healthcare workers and specifically as anesthesiologists. CONCLUSION: A review of available evidence strongly suggests that there may be a link between the effects of GA on the brain and substance abuse, partly explained by their influence on the dopaminergic system.

Micro/nano-structured superhydrophobic surfaces in the biomedical field: part I: basic concepts and biomimetic approaches.

Inspired by natural structures, great attention has been devoted to the study and development of surfaces with extreme wettable properties. The meticulous study of natural systems revealed that the micro/nano-topography of the surface is critical to obtaining unique wettability features, including superhydrophobicity. However, the surface chemistry also has an important role in such surface characteristics. As the interaction of biomaterials with the biological milieu occurs at the surface of the materials, it is expected that synthetic substrates with extreme and controllable wettability ranging from superhydrophilic to superhydrophobic regimes could bring about the possibility of new investigations of cellâ material interactions on nonconventional surfaces and the development of alternative devices with biomedical utility. This first part of the review will describe in detail how proteins and cells interact with micro/nano-structured surfaces exhibiting extreme wettabilities.

Superhydrophobic surfaces as a tool for the fabrication of hierarchical spherical polymeric carriers

Hierarchical polymeric carriers with high encapsulation efficiencies are fabricated via a biocompatible strategy developed using superhydrophobic (SH) surfaces. The carries are obtained by the incorporation of cell/BSA-loaded dextran-methacrylate (DEXT-MA) microparticles into alginate (ALG) macroscopic beads. Engineered devices like these are expected to boost the development of innovative and customizable systems for biomedical and biotechnological purposes.

Antibacterial properties of multifunctional coatings Ag-ZrCN for biomedical devices: a novel approach

PhD in Sciences Specialty in Physics

Surface phenomena and hydrodynamic effects on the deposition of Pseudomonas fluorescens

Biofilm adhesion to metals (copper, aluminium and brass) was studied at two different velocities and pH values of 7 and 9. Both bacteria and metals showed negative surface charges at those values of pH, which tends to slow down adhesion. Film densities increased with the fluid velocity and were also affected by the pH and by the growth rate of the bacteria. Long duration tests based on heat transfer measurements were run at five different fluid velocities and at pH = 7, showing in general an asymptotic behaviour and a control of deposition by adhesion and growth phenomena.

Impact of cerebral cardiopulmonary resuscitation maneuvers in a general hospital: prognostic factors and outcomes

OBJECTIVE: To assess survival of patients undergoing cerebral cardiopulmonary resuscitation maneuvers and to identify prognostic factors for short-term survival. METHODS: Prospective study with patients undergoing cardiopulmonary resuscitation maneuvers. RESULTS: The study included 150 patients. Spontaneous circulation was re-established in 88 (58%) patients, and 42 (28%) were discharged from the hospital. The necessary number of patients treated to save 1 life in 12 months was 3.4. The presence of ventricular fibrillation or tachycardia (VF/VT) as the initial rhythm, shorter times of cardiopulmonary resuscitation maneuvers and cardiopulmonary arrest, and greater values of mean blood pressure (BP) prior to cardiopulmonary arrest were independent variables for re-establishment of spontaneous circulation and hospital discharge. The odds ratios for hospital discharge were as follows: 6.1 (95% confidence interval [CI] = 2.7-13.6), when the initial rhythm was VF/VT; 9.4 (95% CI = 4.1-21.3), when the time of cerebral cardiopulmonary resuscitation was < 15 min; 9.2 (95% CI = 3.9-21.3), when the time of cardiopulmonary arrest was < 20 min; and 5.7 (95% CI = 2.4-13.7), when BP was > 70 mmHg. CONCLUSION: The presence of VF/VT as the initial rhythm, shorter times of cerebral cardiopulmonary resuscitation and of cardiopulmonary arrest, and a greater value of BP prior to cardiopulmonary arrest were independent variables of better prognosis.

A general history of the dichlamydeous plants :comprising complete descriptions of the different orders...the whole arranged according to the natural system /by George Don.

1831 v.1