High-harmonic generation from a confined atom

The order of high harmonics emitted by an atom in an intense laser field is limited by the so-called cutoff frequency. Solving the time-dependent Schr\"odinger equation, we show that this frequency can be increased considerably by a parabolic confining potential, if the confinement parameters are suitably chosen. Furthermore, due to confinement, the radiation intensity remains high throughout the extended emission range. All features observed can be explained with classical arguments.Comment: 4 pages(tex files), 4 figures(eps files); added references and comment

Enhancement of bichromatic high-harmonic generation with a high-frequency field

Using a high-frequency field superposed to a linearly polarized bichromatic laser field composed by a wave with frequency $\omega$ and a wave with frequency $2\omega$, we show it is possible to enhance the intensity of a group of high harmonics in orders of magnitude. These harmonics have frequencies about 30% higher than the monochromatic-cutoff frequency, and, within the three-step-model framework, correspond to a set of electron trajectories for which tunneling ionization is strongly suppressed. Particular features in the observed enhancement suggest that the high-frequency field provides an additional mechanism for the electron to reach the continuum. This interpretation is supported by a time-frequency analysis of the harmonic yield. The additional high frequency field permits the control of this group of harmonics leaving all other sets of harmonics practically unchanged, which is an advantage over schemes involving only bichromatic fields.Comment: 6 pages RevTex, 5 figures (ps files), Changes in text, figures, references and equations include

Pristine Multi-walled carbon nanotubes for a rapid and efficient plasmid DNA clarification

Therapeutic approaches based on nucleic acids to modulate cell activity have recently gained attention. These molecules arise from complex biotechnological processes, requiring effective manufacturing strategies, high purity, and precise quality control to be used as biopharmaceuticals. One of the most critical and time-consuming steps for nucleic acids-based biotherapeutics manufacturing is their purification, mainly due to the complexity of the extracts. In this study, a simple, efficient, and reliable method to isolate and clarify plasmid DNA (pDNA) from complex samples is described. The method is based on the selective capture of RNA and other impurities, using pristine carbon nanotubes (CNTs). Multi-walled CNTs (MWCNTs) with different diameters were studied to determine their adsorption capacity and to address their ability to interact and distinguish between nucleic acids. The results revealed that MWCNTs preferentially interact with RNA and that smaller MWCNTs present a higher adsorption capacity, as expected by the higher specific surface area. Overall, this study showed that MWCNTs significantly reduce the levels of impurities, namely RNA, gDNA, and proteins, by approximately 83.6 % compared to their initial level, enabling the recovery of clarified pDNA in solution while maintaining its stability throughout the recovery process. This method facilitates the pre-purification of pDNA for therapeutic applications.publishe

Wave profile and tide monitoring system for scalable implementation

Apresentação de Poster em conferência Nacional.Presentation of a wave profile and tide monitoring system, with low-cost and low-power pressure sensors connected to a datalogger in a wired or acustic network

Durability assessment of external thermal insulation composite systems in urban and maritime environments

External Thermal Insulation Composite Systems (ETICS) are multilayer solutions which provide an enhanced thermal performance to the building envelope. However, significant anomalies can be detected on ETICS facades, in some cases shortly after the application of these systems. This study intends to evaluate and compare the durability of six commercially available ETICS after two years of outdoor exposure at both urban and maritime conditions in Portugal. The systems were characterized by means of non-destructive testing (i.e., visual and microscopic assessment, water transport properties, thermal conductivity, surface roughness), thus allowing to evaluate the performance loss throughout natural aging. The bio-susceptibility and aesthetic properties (color and gloss) were also investigated. Results showed that the performance and durability of the complete system is significantly affected by the rendering system formulation. The lime-based specimens obtained the highest rate of mold development after one year of aging in a maritime environment, becoming considerably darker and with lower surface gloss. Fungal analysis of this darkish stained area indicated the presence of mold species of the genera Alternaria, Didymella, Cladosporium and Epicoccum, and yeasts of the genera Vishniacozyma and Cystobasidium. An increase of both capillary water absorption and water vapor permeability was also registered for the aged lime-based specimens. Acrylic-based systems obtained lower capillary water absorption after aging and greater dirt deposition on their surfaces, especially in urban conditions. These systems had also higher color variation and surface gloss decrease and slightly higher mold growth, when compared with those aged in a maritime environment. Finally, no mold growth was detected on the silicate-based specimens after two years of aging. However, these specimens obtained higher capillary water absorption and lower vapor permeability after aging, possibly leading to moisture accumulation within the system. Results contribute towards the development of ETICS with enhanced performance and durability.info:eu-repo/semantics/publishedVersio

Fast building – increasing the geometrical freedom of textile reinforced concrete systems

Apresentação efetuada na 9th International Conference Mechanics and Materials in Design - Theory, Experiments and Applications in Engineering (M2D2021), no Funchal, Portugal, 2022[Excerpt] Introduction Textile technology is highly innovative, and several techniques are already being used to act as building parts for fast building, interior design, architectural details and offshore structures. However, such potential still fails when complex geometrical structures or multifunctionality are required.Fundação para a Ciência e a Tecnologia - grant SFRH/BD/144201/2019European Regional Development Fund (FEDER), Operational Program for Competitiveness Factors (COMPETE) POCI-01-0247-312 FEDER-03973

Access to infertility consultations: what women tell us about it?

The main objective of the present paper is to evaluate the perception of women concerning the barriers and access to infertility consultations. Socio cultural and economic access to infertility consultations is detached and three municipalities of the northwest of Portugal were chosen as an example of a peripheral country. A quantitative/qualitative study was done with 60 women. Three dimensions were evaluated: geographic and structural and functional access; economic access; and sociocultural access. The main barriers were mainly identified in the last two dimensions. The economic access was the less well evaluated by women being the cost of treatment (medication, and concentration of costs in a short period) difficult to bear. This can justify a greater involvement of the Portuguese Government, by developing policies for the reimbursement of part of the costs. Also, some changes in structural and functional access must be done with special regard to the separation of the infertility consultations from the reproductive medicine section. The setting of the teams, with a follow-up by the same team of health professionals is also needed