Synthesis and biological evaluation of mono and bis-naphthalimide derivatives against SH-SY5Y, human brain cancer cells

Dissertação de mestrado em Medicinal Chemistry

Contributos para a elucidação do modo de ação de própolis português: o caso do própolis do Pereiro

Dissertação de mestrado em Genética Molecular

Antibacterial Ag/a-C nanocomposite coatings: The influence of nano-galvanic a-C and Ag couples on Ag ionization rates

Biofilm formation has been pointed as a major concern in different industrial applications, namely on biomedical implants and surgical instruments, which has prompted the development of new strategies for production of efficient antimicrobial surfaces. In this work, nano âgalvanic couples were created to enhance the antibacterial properties of silver, by embedding it into amorphous carbon (a-C) matrix. The developed Ag/a-C nanocomposite coatings, deposited by magnetron sputtering, revealed an outstanding antibacterial activity against S.epidermidis, promoting a total reduction in biofilm formation with no bacteria counts in all dilution. The open circuit potential (OCP) tests in 0.9% NaCl confirmed that a-C shows a positive \OCP\ value, in contrast to Ag coating, thus enhancing the ionization of biocidal Ag+ due to the nano-galvanic couple activation. This result was confirmed by the inductively coupled plasma-optical emission spectroscopy (ICP-OES), which revealed a higher Ag ionization rate in the nanocomposite coating in comparison with the Ag coating. The surface of Ag/a-C and Ag coatings immersed in 0.9% NaCl were monitored by scanning electron microscopy (SEM) over a period of 24 hours, being found that the Ag ionization determined by ICP-OES was accompanied by an Ag nanoparticles coalescence and agglomeration in Ag/a-C coating.

Development of active bio-based multilayer systems: encapsulation of cinnamaldehyde and their physicochemical characterization

[Excerpt] In this work, different multilayer structures, using a polyhydroxybutyrate-co-valerate film with a valerate content of 8% (PHBV8) as support, were developed aiming the development of active bio-based multilayer systems. An interlayer based on zein nanofibers with and without cinnamaldehyde were electrospun in the PHBV8 film and three multilayer systems were developed: 1) without an outer layer; 2) using a PHBV8 film as outer layer; and 3) using an alginate-based film as outer layer. Their physico-chemical properties were evaluated through: water vapour and oxygen permeabilities and colour measurements, Fourier Transform Infrared Spectroscopy (FTIR) and thermal analyses. Results showed that the presence of different outer layers affected the water vapour permeability and transparency of the multilayer films. (...)

A design of experiments to assess phosphorous removal and crystal properties in struvite precipitation of source separated urine using different Mg sources

Supplementary data associated with this article can be found, in the online version, at: http://dx.doi.org/10.1016/j.cej.2016.03.148.

Psychometric properties of the Portuguese version of the Posttraumatic Growth Inventory Short Form among divorced adults

The aim of this study was to develop and validate a Portuguese version of the Short Form of the Posttraumatic Growth Inventory (PTGI-SF). Using an online convenience sample of Portuguese divorced adults (N = 482), we confirmed the oblique five-factor structure of the PTGI-SF by confirmatory factor analysis. The results demonstrated the measurement invariance across divorce initiator status groups. Total score and factors of PTGI-SF showed good internal consistency, with the exception of the New Possibilities factor, which revealed an acceptable reliability. The Portuguese PTGI-SF showed a satisfactory convergent validity. In terms of discriminant validity, posttraumatic growth assessed by the Portuguese PTGI-SF was a distinct factor from posttraumatic psychological adjustment. These preliminary findings suggest the cultural adaptation and also psychometric properties of the present Portuguese PTGI-SF to measure posttraumatic growth after personal crisis.

Hierarchical modelling of timber reference properties using probabilistic methods: Maximum Likelihood Method, Bayesian Methods and Probability Networks

In recent decades, an increased interest has been evidenced in the research on multi-scale hierarchical modelling in the field of mechanics, and also in the field of wood products and timber engineering. One of the main motivations for hierar-chical modelling is to understand how properties, composition and structure at lower scale levels may influence and be used to predict the material properties on a macroscopic and structural engineering scale. This chapter presents the applicability of statistic and probabilistic methods, such as the Maximum Likelihood method and Bayesian methods, in the representation of timber’s mechanical properties and its inference accounting to prior information obtained in different importance scales. These methods allow to analyse distinct timber’s reference properties, such as density, bending stiffness and strength, and hierarchically consider information obtained through different non, semi or destructive tests. The basis and fundaments of the methods are described and also recommendations and limitations are discussed. The methods may be used in several contexts, however require an expert’s knowledge to assess the correct statistic fitting and define the correlation arrangement between properties.

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

PhD in Sciences Specialty in Physics

The effects of sodium hypochlorite against selected drinking water-isolated bacteria in planktonic and sessile states

Chlorine is the most commonly used agent for general disinfection, particularly for microbial growth control in drinking water distribution systems. The goals of this study were to understand the effects of chlorine, as sodium hypochlorite (NaOCl), on bacterial membrane physicochemical properties (surface charge, surface tension and hydrophobicity) and on motility of two emerging pathogens isolated from drinking water, Acinetobacter calcoaceticus and Stenotrophomonas maltophilia. The effects of NaOCl on the control of single and dual-species monolayer adhered bacteria (2 h incubation) and biofilms (24 h incubation) was also assessed. NaOCl caused significant changes on the surface hydrophobicity and motility of A. calcoaceticus, but not of S. maltophilia. Planktonic and sessile S. maltophilia were significantly more resistant to NaOCl than A. calcoaceticus. Monolayer adhered co-cultures of A. calcoaceticus-S. maltophilia were more resilient than the single species. Oppositely, dual species biofilms were more susceptible to NaOCl than their single species counterparts. In general, biofilm removal and killing demonstrated to be distinct phenomena: total bacterial viability reduction was achieved even if NaOCl at the higher concentrations had a reduced removal efficacy, allowing biofilm reseed. In conclusion, understanding the antimicrobial susceptibility of microorganisms to NaOCl can contribute to the design of effective biofilm control strategies targeting key microorganisms, such as S. maltophilia, and guarantying safe and high-quality drinking water. Moreover, the results reinforce that biofilms should be regarded as chronic contaminants of drinking water distribution systems and accurate methods are needed to quantify their presence as well as strategies complementary/alternative to NaOCl are required to effectively control the microbiological quality of drinking water.

Experimental procedures for the identification of material properties of intervertebal disc - a contribution for the development of biomimetic substitutes for the nucleus pulposus

Tese de Doutoramento em Engenharia Mecânica.

The role of monocarboxylate transporters in 3-bromopyruvate effect in cancer cells

Tese de Doutoramento em Biologia Molecular e Ambiental (área de especialização em Biologia Molecular e Saúde).

Evaluation of antimicrobial strategies against biomaterial-associated infections: impact of the surrounding environmental conditions

Dissertação de mestrado em Bioengenharia

Flora vitiensis :a description of the plants of the Viti or Fiji islands, with an account of their history, uses, and properties /By Berthold Seemann; ... plates by Walter Fitch.

v. 1

Flora vitiensis :a description of the plants of the Viti or Fiji islands, with an account of their history, uses, and properties /By Berthold Seemann; ... plates by Walter Fitch.

v. 2

Producción de compuestos antimicrobianos por Pseudomonas nativas de la region de Córdoba. Production of antimicrobial compounds by native Pseudomonas from region of Cordoba.

La agricultura moderna se basa en el empleo de fertilizantes y pesticidas químicos para aumentar la productividad y para el control de enfermedades de los cultivos; sin embargo, existe una tendencia a disminuir su uso en la agricultura debido a los efectos negativos sobre la salud humana y el medio ambiente. Una estrategia alternativa al uso de agroquímicos es el empleo de microorganismos capaces de promover el crecimiento vegetal y/o actuar como agentes de biocontrol. A la hora de formular un inoculante se debe tener en cuenta que la cepa sea competitiva. A pesar de que se conoce poco sobre el rol de las bacteriocinas en el medio ambiente; se ha observado que bacterias productoras de bacteriocinas son más competitivas. Además estos metabolitos pueden ser utilizados también para el control biológico de bacterias patógenas. En el laboratorio se cuenta con cepas de Pseudomonas aislados de la rizósfera de cereales de la provincia de Córdoba. Pseudomonas sp. SF4c (cepa nativa de trigo), secreta una bacteriocina de alto peso molecular, aun no caracterizada. HIPOTESIS: El empleo de formulaciones en base a cepas nativas competitivas, altamente eficientes para la promoción del crecimiento vegetal y el control biológico permitirá disminuir el uso de agroquímicos incrementando la producción y/o calidad de los cultivos. Objetivos específicos: 1. Evaluar la capacidad de Pseudomonas nativas de inhibir el crecimiento de hongos fitopatógeno. 2. Analizar la producción de bacteriocinas en Pseudomonas spp. 3. Purificar parcialmente la bacteriocina secretada por Pseudomonas sp. SF4c. Para llevar a cabo este proyecto, - Se probará la capacidad de Pseudomonas de inhibir el crecimiento de hongos fitopatógenos en medio agar dextrosa papa. En las cepas biocontroladoras, se buscarán los genes implicados en la síntesis de metabolitos secundarios, mediante PCR usando primer específicos. - Se analizará la producción de bacteriocinas en Pseudomonas nativas. En las cepas bacteriocinogénicas se realizarán estudios adicionales para conocer la estabilidad de estos compuestos (sensibilidad a enzimas proteolíticas, calor, UV). -Se purificará la bacteriocina secretada por Pseudomonas sp. SF4C, mediante cromatografía de exclusión molecular, las fracciones recogidas serán analizados en geles de poliacrilamida. La identificación de la proteína será realizada por espectrometría de masa MALDI-TOF. Se espera encontrar dentro de la colección, cepas capaces de controlar el desarrollo de hongos fitopatógenos, dilucidar los mecanismos mediante el cual ejerce su efecto de biocontrol y avanzar en el conocimiento de nuevas bacteriocinas. A nivel industrial, existe en el futuro la posibilidad de que estas bacterias puedan ser utilizadas en la formulación de inoculantes para ser usados en la fertilización de cultivos de cereales que son de gran importancia económica para la región, y/o como agentes de control biológico.