Estudo da sinterização de cavacos de aço ferritico

This research studies the sintering of ferritic steel chips from the machining process. Were sintered metal powder obtained from machining process chips for face milling of a ferritic steel. The chip was produced by machining and characterized by SEM and EDS, and underwent a process of high energy mill powder characterized also by SEM and EDS. Were constructed three types of matrixes for uniaxial compression (relation l / d greater than 2.5). The differences in the design of the matrixes were essentially in the direction of load application, which for cylindrical case axial direction, while for the rectangular arrays, the longer side. Two samples were compressed with different geometries, a cylindrical and rectangular with the same compaction pressure of 700 MPa. The samples were sintered in a vacuum resistive furnace, heating rate 20 °C / min., isotherm 1300 °C for 60 minutes, and cooling rate of 25 °C / min to room temperature. The starting material of the rectangular sample was further annealed up to temperature of 800 ° C for 30 min. Sintered samples were characterized by scanning electron microscopy, optical microscopy and EDS. The sample compressed in the cylindrical matrix did not show a regular density reflecting in the sintered microstructure revealed by the irregular geometry of the pores, characterizing that the sintering was not complete, reaching only the second phase. As for the specimen compacted in the rectangular array, the analysis performed by scanning electron microscopy, optical microscopy and EDS indicate a good densification, and homogeneous microstructure in their full extent. Additionally, the EDS analyzes indicate no significant changes in chemical composition in the process steps. Therefore, it is concluded that recycling of chips, from the processed ferritic steel is feasible by the powder metallurgy. It makes possible rationalize raw material and energy by manufacture of known properties components from chips generated by the machining process, being benefits to the environment

Microfluidics-based single-cell functional proteomics microchip for portraying protein signal transduction networks within the framework of physicochemical principles, with applications in fundamental and translational cancer research

Single-cell functional proteomics assays can connect genomic information to biological function through quantitative and multiplex protein measurements. Tools for single-cell proteomics have developed rapidly over the past 5 years and are providing unique opportunities. This thesis describes an emerging microfluidics-based toolkit for single cell functional proteomics, focusing on the development of the single cell barcode chips (SCBCs) with applications in fundamental and translational cancer research.

The microchip designed to simultaneously quantify a panel of secreted, cytoplasmic and membrane proteins from single cells will be discussed at the beginning, which is the prototype for subsequent proteomic microchips with more sophisticated design in preclinical cancer research or clinical applications. The SCBCs are a highly versatile and information rich tool for single-cell functional proteomics. They are based upon isolating individual cells, or defined number of cells, within microchambers, each of which is equipped with a large antibody microarray (the barcode), with between a few hundred to ten thousand microchambers included within a single microchip. Functional proteomics assays at single-cell resolution yield unique pieces of information that significantly shape the way of thinking on cancer research. An in-depth discussion about analysis and interpretation of the unique information such as functional protein fluctuations and protein-protein correlative interactions will follow.

The SCBC is a powerful tool to resolve the functional heterogeneity of cancer cells. It has the capacity to extract a comprehensive picture of the signal transduction network from single tumor cells and thus provides insight into the effect of targeted therapies on protein signaling networks. We will demonstrate this point through applying the SCBCs to investigate three isogenic cell lines of glioblastoma multiforme (GBM).

The cancer cell population is highly heterogeneous with high-amplitude fluctuation at the single cell level, which in turn grants the robustness of the entire population. The concept that a stable population existing in the presence of random fluctuations is reminiscent of many physical systems that are successfully understood using statistical physics. Thus, tools derived from that field can probably be applied to using fluctuations to determine the nature of signaling networks. In the second part of the thesis, we will focus on such a case to use thermodynamics-motivated principles to understand cancer cell hypoxia, where single cell proteomics assays coupled with a quantitative version of Le Chatelier's principle derived from statistical mechanics yield detailed and surprising predictions, which were found to be correct in both cell line and primary tumor model.

The third part of the thesis demonstrates the application of this technology in the preclinical cancer research to study the GBM cancer cell resistance to molecular targeted therapy. Physical approaches to anticipate therapy resistance and to identify effective therapy combinations will be discussed in detail. Our approach is based upon elucidating the signaling coordination within the phosphoprotein signaling pathways that are hyperactivated in human GBMs, and interrogating how that coordination responds to the perturbation of targeted inhibitor. Strongly coupled protein-protein interactions constitute most signaling cascades. A physical analogy of such a system is the strongly coupled atom-atom interactions in a crystal lattice. Similar to decomposing the atomic interactions into a series of independent normal vibrational modes, a simplified picture of signaling network coordination can also be achieved by diagonalizing protein-protein correlation or covariance matrices to decompose the pairwise correlative interactions into a set of distinct linear combinations of signaling proteins (i.e. independent signaling modes). By doing so, two independent signaling modes – one associated with mTOR signaling and a second associated with ERK/Src signaling have been resolved, which in turn allow us to anticipate resistance, and to design combination therapies that are effective, as well as identify those therapies and therapy combinations that will be ineffective. We validated our predictions in mouse tumor models and all predictions were borne out.

In the last part, some preliminary results about the clinical translation of single-cell proteomics chips will be presented. The successful demonstration of our work on human-derived xenografts provides the rationale to extend our current work into the clinic. It will enable us to interrogate GBM tumor samples in a way that could potentially yield a straightforward, rapid interpretation so that we can give therapeutic guidance to the attending physicians within a clinical relevant time scale. The technical challenges of the clinical translation will be presented and our solutions to address the challenges will be discussed as well. A clinical case study will then follow, where some preliminary data collected from a pediatric GBM patient bearing an EGFR amplified tumor will be presented to demonstrate the general protocol and the workflow of the proposed clinical studies.

On-demand generation and removal of alginate biocompatible microvalves for flow control in microfluidics

[EN] This paper describes, for the first time, the use of alginate hydrogels as miniaturised microvalves within microfluidic devices. These biocompatible and biodegradable microvalves are generated in situ and on demand, allowing for microfluidic flow control. The microfluidic devices were fabricated using an origami inspired technique of folding several layers of cyclic olefin polymer followed by thermocompression bonding. The hydrogels can be dehydrated at mild temperatures, 37◦C, to slightly open the microvalve and chemically erased using an ethylenediaminetetraacetic acid disodium salt (EDTA) solution, to completely open the channel, ensuring the reusability of the whole device and removal of damaged or defective valves for subsequent regeneration.

Portable “lab-on-chip” platform for bovine mastitis diagnosis in raw milk

Tese de Doutoramento em Ciências Veterinárias, Especialidade de Ciências Biológicas e Biomédicas

Análisis de la expresión de miRNAs en trofozoítos de entamoeba histolytica.

Entamoeba histolytica representa una de las principales causas a nivel mundial de muertes por parasitosis. Aunque se ha identificado como el agente causal de la amibiasis desde 1875, los mecanismos moleculares por los cuales este parásito causa la enfermedad aún no estan completamente comprendidos. Los microRNAs (miRNAs) son grupos de RNAs pequeños no codificantes que juegan un papel importante en la regulación de la expresión de genes y la traducción de proteínas en una gran variedad de organismos. Su identificación ha sido un paso importante para facilitar y entender la biología, organización y evolución del genoma, así como su regulación posttranscripcional, sin embargo en E. histolytica no se tiene registro de la presencia de estas moléculas reguladoras. En nuestro laboratorio a partir de un cultivo de trofozoitos de E. histolytica en condiciones axénicas se aislaron los RNA totales y se purificaron en una fracción de 15 a 50 nucleótidos los cuales se utilizaron para construir una biblioteca de RNAs pequeños que posteriormente fueron secuenciados y en donde se detectaron 199 miRNAs exclusivos para este parásito. Durante el desarrollo de esta tesis, se analizó la expresión de miRNAs en trofozoítos de E. histolytica HM1-IMSS, usando la técnica de microarreglo µParaflo Microfluidic Biochip Technology y posteriormente se realizó la verificación de la expresión de los miRNAs mediante RT-PCR Tiempo Real. Los resultados del microarreglo demostraron la expresión 41 candidatos a miRNAs de los cuales se confirmó la presencia de 9 microRNAs de E. histolytica (Ehi-miRNAs) mediante RT-PCR Tiempo Real. La estructura de los Ehi-miRNAs permitió predecir 32 probables genes blanco ya descritos y 34 genes hipotéticos probables. Los resultados obtenidos postulan una colección de miRNAs reguladores en E. histolytica que generan una plataforma para analizar molecularmente la estructura genómica, regulación génica y validación de los Ehi-miRNAs en este parásito

Avaliação do potencial energético de cana (Arundo donax L.) no Algarve

Dissertação de Mestrado, Energias Renováveis e Gestão de Energia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016

Tecnologia e funcionalidade das peças esquiroladas do Paleolítico Superior de Vale Boi, Vila do Bispo

Dissertação de Mestrado, Arqueologia, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2016

Desempenho de novilhos suplementados no periodo seco com mistura multipla a base de leucena no semi-arido brasileiro.

O estudo objetivou avaliar uma mistura multipla composta de feno de folhas de leucena (Leucaena leucocephala (Lam.) de Wit.), raspa de mandioca e uma mistura mineral, como suplemento para novilhos azebuados, no periodo seco. A mistura foi comparada com duas outras alternativas de suplementacao: a mistura sal-ureia e a silagem de leucena. Os animais dos tres grupos pastejaram, conjuntamente, em capim buffel (Cenchrus ciliaris, L.). Ao final dos 84 dias do periodo experimental, o incremento em peso vivo nos animais submetidos a mistura multipla (22,1 kg/cab) nao diferiu (P>0,05) do observado nos animais suplementados com silagem de leucena (17,7 kg/cab), mas correspondeu (P<0,05) a quase cinco vezes o observado nos animais submetidos a mistura sal-ureia (4,6 kg/cab).

The importance of taste on dietary choice, behaviour and intake in a group of young adults

The 'taste of food' plays an important role in food choice. Furthermore, foods high in fat, sugar and salt are highly palatable and associated with increased food consumption. Research exploring taste importance on dietary choice, behaviour and intake is limited, particularly in young adults. Therefore, in this study a total of 1306 Australian university students completed questionnaires assessing dietary behaviors (such as how important taste was on food choice) and frequency of food consumption over the prior month. Diet quality was also assessed using a dietary guideline index. Participants had a mean age of 20 ± 5 years, Body Mass Index (BMI) of 22 ± 3 kg/m(2), 79% were female and 84% Australian. Taste was rated as being a very or extremely important factor for food choice by 82% of participants. Participants who rated taste as highly important, had a poorer diet quality (p = 0.001) and were more likely to consume less fruit (p = 0.03) and vegetables (p = 0.05). Furthermore, they were significantly more likely to consume foods high in fat, sugar and salt, including chocolate and confectionary, cakes and puddings, sweet pastries, biscuits, meat pies, pizza, hot chips, potato chips, takeaway meals, soft drink, cordial and fruit juice (p = 0.001-0.02). They were also more likely to consider avoiding adding salt to cooking (p = 0.02) and adding sugar to tea or coffee (p = 0.01) as less important for health. These findings suggest that the importance individuals place on taste plays an important role in influencing food choice, dietary behaviors and intake.

Machining of coarse grained and ultra fine grained titanium

Machining of titanium is quite difficult and expensive. Heat generated in the process of cutting does not dissipate quickly, which affects tool life. In the last decade ultra fine grained (UFG) titanium has emerged as an option for substitution for more expensive titanium alloys. Extreme grain refinement can be readily performed by severe plastic deformation techniques. Grain refinement of a material achieved in this way was shown to change its mechanical and physical properties. In the present study, the microstructure evolution and the shear band formation in chips of coarse grained and UFG titanium machined to three different depths and three different feeding rates was investigated. A change in thermal characteristics of commercial purity Ti with grain refinement was studied by comparing heating/cooling measurements with an analytical solution of the heat transfer boundary problem. It was demonstrated that an improvement in the machinability can be expected for UFG titanium. © 2012 Springer Science+Business Media, LLC.

Comparison of different extrusion methods for compaction of powders

Densification of metallic powders by means of extrusion is regarded as a very attractive processing technique that allows obtaining a high level of relative density of the compact. However, the uniformity of the relative density depends on that of strain distribution and on the processing parameters. Several variants of extrusion can be used for compaction of metal particulates, including the conventional extrusion (CE) and equal channel angular pressing (ECAP), often referred to as equal-channel angular extrusion. Each of these processes has certain advantages and drawbacks with respect to compaction. A comparative study of these two extrusion processes influencing the relative density of compacts has been conducted by numerical simulation using commercial finite element software DEFORM2D. The results have been validated by experiments with titanium and magnesium powders and chips.

Fluorine-free superhydrophobic coatings with pH-induced wettability transition for controllable oil-water separation

We present a simple, environmentally friendly approach to fabricating superhydrophobic coatings with pH-induced wettability transition. The coatings are prepared from a mixture of silica nanoparticles and decanoic acid-modified TiO2. When the coating is applied on cotton fabric, the fabric turns superhydrophobic in air but superoleophilic in neutral aqueous environment. It is permeable to oil fluids but impermeable to water. However, when the coated fabric is placed in basic aqueous solution or ammonia vapor, it turns hydrophilic but underwater superoleophobic, thus allowing water to penetrate through but blocking oil. Therefore, such a unique, selective water/oil permeation feature makes the treated fabric have capability to separate either oil or water from a water-oil mixture. It may be useful for development of smart oil-water separators, microfluidic valves, and lab-on-a-chip devices.

Clustering of adherence to personalised dietary recommendations and changes in healthy eating index within the Food4Me study

OBJECTIVE: To characterise clusters of individuals based on adherence to dietary recommendations and to determine whether changes in Healthy Eating Index (HEI) scores in response to a personalised nutrition (PN) intervention varied between clusters.

DESIGN: Food4Me study participants were clustered according to whether their baseline dietary intakes met European dietary recommendations. Changes in HEI scores between baseline and month 6 were compared between clusters and stratified by whether individuals received generalised or PN advice.

SETTING: Pan-European, Internet-based, 6-month randomised controlled trial.

SUBJECTS: Adults aged 18-79 years (n 1480).

RESULTS: Individuals in cluster 1 (C1) met all recommended intakes except for red meat, those in cluster 2 (C2) met two recommendations, and those in cluster 3 (C3) and cluster 4 (C4) met one recommendation each. C1 had higher intakes of white fish, beans and lentils and low-fat dairy products and lower percentage energy intake from SFA (P<0·05). C2 consumed less chips and pizza and fried foods than C3 and C4 (P<0·05). C1 were lighter, had lower BMI and waist circumference than C3 and were more physically active than C4 (P<0·05). More individuals in C4 were smokers and wanted to lose weight than in C1 (P<0·05). Individuals who received PN advice in C4 reported greater improvements in HEI compared with C3 and C1 (P<0·05).

CONCLUSIONS: The cluster where the fewest recommendations were met (C4) reported greater improvements in HEI following a 6-month trial of PN whereas there was no difference between clusters for those randomised to the Control, non-personalised dietary intervention.

Industrial lab-on-a-chip: design, applications and scale-up for drug discovery and delivery

Microfluidics is an emerging and promising interdisciplinary technology which offers powerful platforms for precise production of novel functional materials (e.g., emulsion droplets, microcapsules, and nanoparticles as drug delivery vehicles- and drug molecules) as well as high-throughput analyses (e.g., bioassays, detection, and diagnostics). In particular, multiphase microfluidics is a rapidly growing technology and has beneficial applications in various fields including biomedicals, chemicals, and foods. In this review, we first describe the fundamentals and latest developments in multiphase microfluidics for producing biocompatible materials that are precisely controlled in size, shape, internal morphology and composition. We next describe some microfluidic applications that synthesize drug molecules, handle biological substances and biological units, and imitate biological organs. We also highlight and discuss design, applications and scale up of droplet- and flow-based microfluidic devices used for drug discovery and delivery.

Directional fluid transport in thin porous materials and its functional applications

Directional fluid motion driven by the surface property of solid substrate is highly desirable for manipulating microfluidic liquid and collecting water from humid air. Studies on such liquid motion have been confined to dense material surfaces such as flat panels and single filaments. Recently, directional fluid transport through the thickness of thin porous materials has been reported by several research groups. Their studies not only attract fundamental, experimental and theoretical interest but also open novel application opportunities. This review article summarizes research progress in directional fluid transport across thin porous materials. It focuses on the materials preparation, basic properties associated with directional fluid transport in thin porous media, and their application development. The porous substrates, type of transporting fluids, structure-property attributes, and possible directional fluid transport mechanism are discussed. A perspective for future development in this field is proposed.