6,659 research outputs found
A Computational Study of Blood Flow and Vascular Nitric Oxide Transport
Atherosclerosis occurs in a spatially heterogeneous fashion within the arterial system.
The patchy nature of the disease is thought to reflect spatial variation in
haemodynamic factors such as wall shear stress (WSS) and in the concentration of
vascular species. This thesis numerically investigates blood flow and vascular transport
of the atheroprotective agent nitric oxide (NO) using a spectral/hp element
method.
Firstly, NO distribution is analysed within a parallel-plate flow chamber coated
with endothelial cells. Contrary to the accepted hypothesis that NO concentration
increases with WSS (as does NO production), it is observed that NO concentration
depends on WSS in a non-monotonic fashion. Furthermore, these results emphasise
the effect of convection on in vitro NO transport, which has been overlooked or
misinterpreted in most previous computational studies.
Secondly, blood flow and NO transport are investigated within a detailed representation
of the rabbit thoracic aorta and its branches, which was reconstructed using high
resolution computed tomography (CT) scan data of a vascular corrosion cast. The
computed WSS distribution exhibits significant spatial heterogeneity, reflecting the
complexity of the blood flow. In particular it is observed that two Dean-type vortices
(associated with a skewed velocity profile) form in the aortic arch and propagate
along the descending aorta. This results in streaks of WSS similar in nature to the
fatty streaks of early stage atherosclerosis observed in mature rabbits. This finding
provides further support for the hypothesis that blood flow mediates atherogenesis. The vascular distribution of NO is found to depend significantly on the relationship
between NO production and WSS. Furthermore, it is concluded that mechanisms
preventing NO consumption by haemoglobin (such as diffusional barriers) must exist
in order for NO to exert its atheroprotective action. This study represents the first effort to model NO transport in a realistic representation of the major arteries
Shannon entropy and particle decays
We deploy Shannon's information entropy to the distribution of branching
fractions in a particle decay. This serves to quantify how important a given
new reported decay channel is, from the point of view of the information that
it adds to the already known ones. Because the entropy is additive, one can
subdivide the set of channels and discuss, for example, how much information
the discovery of a new decay branching would add; or subdivide the decay
distribution down to the level of individual quantum states (which can be
quickly counted by the phase space). We illustrate the concept with some
examples of experimentally known particle decay distributions.Comment: 12 pages, 18 plots; to appear in Nuclear Physics
Music Learning Tools for Android Devices
In this paper, a musical learning application for
mobile devices is presented. The main objective is to design and develop an application capable of offering exercises to practice and improve a selection of music skills, to users interested
in music learning and training. The selected music skills are rhythm, melodic dictation and singing. The application includes an audio signal analysis system implemented making use of the
Goertzel algorithm which is employed in singing exercises to check if the user sings the right musical note. This application also includes a graphical interface to represent musical symbols.
A set of tests were conducted to check the usefulness of the application as musical learning tool. A group of users with different music knowledge have tested the system and reported
to have found it effective, easy and accessible.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Study of the impact of technological innovations on the sustainable freight transport
Ferreira, Ana Cristina, e outros (2023) - International conference on technology management and operations. - Lisboa : Universidade Lusíada Editora. - ISBN 978-898-640-273-0.When considering the environmental impact of freight transport, the road mode assumes special relevance due to differences in environmental performance, mainly in terms of resource consumption and greenhouse gas (GHG) emissions, in addition to other pollutants and noise. To make freight transport more environmentally sustainable, the European Commission’s plan is the Sustainable and Intelligent Mobility Strategy, which aims to sharply reduce transport emissions by 2050. In this sense, technology and innovation should be part of the companies’ objectives, to promote sustainable and continued development. This study was developed with the main purpose of understanding whether road freight transport companies in Portugal use new technologies to adopt a more sustainable environmental behaviour. This research also allowed a better comprehension of the types of investments being made, the main reasons that lead companies to invest in technology, and to understand the main difficulties associated with the adoption of sustainable measures. The data to support this study were collected through an online questionnaire directed to medium and large companies. The answers obtained correspond to 12% of the population. The large and medium-sized Portuguese companies that answered the survey are aware of and are investing in technological innovations with a view to sustainable goods transport. They understand the importance of including sustainable practices in the definition of their strategies, specially in route management and cargo planning and consolidation. Investing in technology is a unanimous strategy used to reduce GHG emissions and the reasons that lead companies to invest are the improvement in environmental performance, cost control and the consequent achievement of competitive advantages. It was highlighted that hydrogen will play a key role in the energy transition because it has storage capacity and flexibility to be used also in various sectors of the economy, being seen as the best solution for heavy duty vehicles
Sleep Efficiency and Perceived Sleep Quality Mediate Cardiometabolic Risk and Psychological Distress
A haplotype-resolved draft genome of the European sardine (Sardina pilchardus)
The European sardine (Sardina pilchardus Walbaum, 1792) is culturally and economically important throughout its distribution. Monitoring studies of sardine populations report an alarming decrease in stocks due to overfishing and environmental change, which has resulted in historically low captures along the Iberian Atlantic coast. Important biological and ecological features such as population diversity, structure, and migratory patterns can be addressed with the development and use of genomics resources.Agência financiadora
Portuguese national funds from FCT-Foundation for Science and Technology: UID/Multi/04326/2016; European Regional Development Fund (FEDER): 22153-01/SAICT/2016; ALG-01-0145-FEDER-022121; ALG-01-0145-FEDER-022231;
MAR2020 operational programme of the European Maritime and Fisheries Fund (project SARDI-NOMICS):
MAR-01.04.02-FEAMP-0024;
European Union's Horizon 2020 research and innovation programme: 654008info:eu-repo/semantics/publishedVersio
High performance novel gadolinium doped ceria/yttria stabilized zirconia/nickel layered and hybrid thin film anodes for application in solid oxide fuel cells
Magnetron sputtering under oblique angle deposition was used to produce Ni-containing ultra thin film anodes comprising alternating layers of gadolinium doped ceria (GDC) and yttria stabilized zirconia (YSZ) of either 200 nm or 1000 nm thickness. The evolution of film structure from initial deposition, through calcination and final reduction was examined by XRD, SEM, TEM and TOF-SIMS. After subsequent fuel cell usage, the porous columnar architecture of the two-component layered thin film anodes was maintained and their resistance to delamination from the underlying YSZ electrolyte was superior to that of corresponding single component Ni-YSZ and Ni-GDC thin films. Moreover, the fuel cell performance of the 200 nm layered an- odes compared favorably with conventional commercially available thick anodes. The observed dependence of fuel cell performance on individual layer thicknesses prompted study of equivalent but more easily fabricated hybrid anodes consisting of simultaneously deposited Ni-GDC and Ni-YSZ, which procedure resulted in exceptionally intimate mixing and interaction of the components. The hybrids exhibited very unusual and favorable I---V characteristics, along with exceptionally high power densities at high currents. Their discovery is the principal contribution of the present work.European Union's Seventh Framework Programme FP7/2007–2013Fuel Cells and Hydrogen Joint Technology Initiative under the T-CELL project, grant 298300MINECO (Spain), grants nº MAT2013-40852RJuan de la Cierva Programme FPDI-2013-1862
Tripeptide Self-Assembly into Bioactive Hydrogels: Effects of Terminus Modification on Biocatalysis
Bioactive hydrogels based on the self-assembly of tripeptides have attracted great interest in recent years. In particular, the search is active for sequences that are able to mimic enzymes when they are self-organized in a nanostructured hydrogel, so as to provide a smart catalytic (bio)material whose activity can be switched on/off with assembly/disassembly. Within the diverse enzymes that have been targeted for mimicry, hydrolases find wide application in biomaterials, ranging from their use to convert prodrugs into active compounds to their ability to work in reverse and catalyze a plethora of reactions. We recently reported the minimalistic l-His-d-Phe-d-Phe for its ability to self-organize into thermoreversible and biocatalytic hydrogels for esterase mimicry. In this work, we analyze the effects of terminus modifications that mimic the inclusion of the tripeptide in a longer sequence. Therefore, three analogues, i.e., N-acetylated, C-amidated, or both, were synthesized, purified, characterized by several techniques, and probed for self-assembly, hydrogelation, and esterase-like biocatalysis. This work provides useful insights into how chemical modifications at the termini affect self-assembly into biocatalytic hydrogels, and these data may become useful for the future design of supramolecular catalysts for enhanced performance
Characterization of dextrin hydrogels by FTIR spectroscopy and solid state NMR spectroscopy
Fourier transform infrared (FTIR) and 13C solid state nuclear magnetic resonance (NMR)
spectroscopy were used to study dextrin structural changes occurring upon hydrogel formation
by vinyl acrylate (VA) grafting and subsequent free radical polymerization. The
degrees of VA substitution (DS) and polymerization (DP) were quantified up to 40%VA
by FTIR intensity measurements and partial least squares (PLS)/FTIR, the latter being a faster
and less error-prone method. Above 40%VA, both parameters are underestimated by
FTIR. A spin counting NMR experiment showed high carbon observabilities for hydrogels
and improved PLS/NMR models were achieved for DS and DP determination. Alternative
NMR integration methods are hindered by the broad VA peaks and need for area correction,
due to their CP dynamics. NMR changes in C1 profile showed that a single helical conformation
predominates at lower %VA, being replaced by disordered conformations as %VA
increases. Furthermore, a correlation FTIR/NMR study indicated that ring conformations
are significantly affected in hydrogels, compared to unpolymerized dextrin.Funding is acknowledged from the Foundation for Science
and Technology, Portugal, for project POCI/QUI/
56229/2004 and grants for H.G. and C.G. (SFRH/22242/
2005). The authors also wish to acknowledge CICECO for
partial funding of this work.Fundação para a Ciência e a Tecnologia (FCT
La construcción de una metodología feminista cualitativa de enfoque narrativo-crítico
Se presenta una metodología cualitativa narrativa crítica como un formato posible y coherente con las bases teóricas de los feminismos, para mostrar la importancia política y ética de los proyectos feministas, en especial, el compromiso con el cambio socia l de la metodología feminista, y con la investigación en general. Con base epistemológica en los principios y criterios del Constructivismo Social , el Feminismo Post -Estructuralista y la Teoría Queer, la metodología utilizada como ejemplo para esta discusi ón fue aplicada en un estudio doctoral que investigó el proceso de construcción -deconstrucción de las subjetividades masculinas con un enfoque terapéutico, en el marco de un programa público de atención a hombres que ejercieron violencia contra mujeres. A través de este ejemplo empírico, se observó que este formato analítico ofrece herramientas para una reflexión crítica sobre las metodologías feministas. Se estableció que el uso de esta metodología específica permite una mejor visualización del problema de la violencia. Se destaca la necesidad de nuevos paradigmas que promuevan el compromiso ético y político, que incluyan contribuciones y permitan el diálogo con avances históricos feministas y estudios de hombres y masculinidades.A critical narrative qualitative methodology is presented as a possible and coherent format with the theoretical bases of feminisms, to show the political and ethical importance of feminist projects, especially the commitment to the social change of feminist methodology, and to the Research in general. With an epistemological basis in the principles and criteria of social co nstructivism, Post -Structural Feminism and Queer Theory, the methodology used a s an example for this discussion was applied in a doctoral study that investigated the process of construction -deconstruction of masculine subjectivities with a Therapeutic approach, within the framework of a public program of care for men who exercised vi olence against women. Through this empirical example, it was observed that this analytical format offers tools for a critical reflection on feminist methodologies. It was established that the use of this specific methodology allows a better visualization o f the problem of violence. It highlights the need for new paradigms that promote ethical and political commitment, which include contributions and allow dialogue with feminist historical advances and studies of men and masculinitie
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