Amplificador Doherty e antena combinadora

The conventional Doherty architecture is commonly used in wireless transmitters for its ability to boost the average efficiency of a traditional single-ended class B amplifier. It consists of two parallel single-ended amplifying branches (named carrier and peaking amplifiers) which are linked, at the output, through a /4 combiner. This output combiner commonly has a significant impact on the overall bandwidth, as it is usually built from a transmission line structure with tuned dimensions. Other non-conventional combining structures could be designed, targeting a wider bandwidth, contributing to an overall increase of the Doherty amplifier’s bandwidth. Being this an high relevance research topic for the development of high efficient and broadband amplifiers, it is highly desirable to have a laboratory setup that implements a Doherty power amplifier to which distinct output combiner structures can be connected and tested. In that sense, the design of two single-ended amplifiers (the carrier and the peaking) was performed in a circuit simulator (ADS, from Keysight) together with the input power divider that compose the Doherty architecture. The Doherty amplifier main board was designed to incorporate the carrier and peaking amplifiers, and also the power splitter at the input, and it was prepared so that it could be connected to any desired combiner to be tested. A traditional Doherty power combiner was designed and both boards (Doherty amplifier and the combiner) were produced, connected and tested in the RF laboratory. The measured amplifier presented the typical caractheristics of a Doherty amplifier with nearly 75% of drain efficiency at full-power, and nearly 50% at the output back-off level. In addition, a second combiner unit was designed with two purposes. The first was to demonstrate the operation of the designed Doherty amplifier with a distinct output combiner, showing that, as intended in this work, it is suited to test multiple combiner structures. The second objective was to serve as preliminary test to evaluate the possibility of merging the output combiner with the antenna element. Taking advantage of the electromagnetic coupling between antennas, this second combiner structure uses two antenna elements that were tuned to simultaneously behave as output combiner of the Doherty amplifier and a radiating element.A arquitetura Doherty convencional é tipicamente utilizada em transmissores sem fios pela sua capacidade de aumentar a eficiência média de um tradicional amplificador em classe B. O amplificador Doherty consiste em dois amplificadores em paralelo (chamados de amplificadores carrier e peaking) que são ligados, na saída, através de um combinador de /4. Este combinador de saída geralmente tem um impacto significativo na largura de banda do amplificador, pois é tipicamente construído a partir de uma estrutura de linhas de transmissão com dimensões ajustadas para uma frequência. Outras estruturas de combinadores não convencionais podem ser projetadas, visando uma largura de banda maior, contribuindo para um aumento geral da largura de banda do amplificador Doherty. Sendo este um tópico de investigação de elevada relevância para o desenvolvimento de amplificadores de alta eficiência e largura de banda, seria interessante ter um setup de laboratório que implemente um amplificador de potência Doherty para o qual estruturas combinadoras distintas possam ser ligadas à saída do amplificador e testadas. Nesse sentido, o projeto de dois amplificadores (carrier e peaking) foi realizado num simulador de circuitos (ADS, da Keysight) junto com o divisor de potência de entrada que compõe a arquitetura Doherty. A placa principal do amplificador Doherty foi projetada para incorporar os amplificadores carrier e peaking, e também o divisor de potência na entrada, e foi preparada de modo que pudesse ser ligada a qualquer combinador desejado a ser testado. Um combinador de potência Doherty tradicional foi projetado e ambas as placas (amplificador Doherty e o combinador) foram produzidas, soldadas e testadas no laboratório de RF. O amplificador medido apresentou as características típicas de um amplificador Doherty com aproximadamente 75% de eficiência de dreno na potência máxima e aproximadamente 50% no ponto de output back-off. Além disso, foi projetado um segundo combinador com dois objetivos. O primeiro foi demonstrar o funcionamento do amplificador Doherty projetado com um combinador de saída distinto, mostrando que, como pretendido neste trabalho, o amplificador desenhado é adequado para testar múltiplas estruturas combinadoras. O segundo objetivo foi servir como teste preliminar para avaliar a possibilidade de fundir o combinador de saída com a antena. Aproveitando o acoplamento eletromagnético entre antenas, esta segunda estrutura combinadora utiliza duas antenas que foram projetadas para se comportarem simultaneamente como combinador de saída do amplificador Doherty e como elemento radiante.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Application of commercial disinfectants to improve chestnut fruit sanitation

Fresh European chestnut (Castanea sativa Mill.) gas intermediate perisability charactyeristics between fresh and dried fruitsFoundation for Science and Technology (FCT, Portugal) - national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2020).info:eu-repo/semantics/publishedVersio

Neural gliding and neural tensioning differently impact flexibility, heat and pressure pain thresholds in asymptomatic subjects: a randomized, parallel and double-blind study

Objective: To compare the effect of neural gliding and tensioning on hamstring flexibility, nerve function (heat and cold thresholds) and pain sensitivity (pain intensity and pressure pain threshold) of the mobilized and non-mobilized lower limbs at post-intervention and 24 h follow up. Design: Randomized, parallel and double blinded trial. Setting/participants: Forty-eight asymptomatic participants. Intervention(s): Participants received neural gliding (n ¼ 23) or tensioning (n ¼ 25). Main Outcome Measures e Straight leg raising (SLR; in degrees), heat and cold threshold (ºC), pressure pain threshold (PPT; in Kgf) and pain intensity (visual analogue scale), taken at baseline, post- intervention and at 24 h follow up. Results: There was a significant interaction between time, intervention and limb for SLR (F2,45 ¼ 3.83; p ¼ 0.029). A significant interaction between time and intervention for PPT (F2,45 ¼ 3.59; p ¼ 0.036) and heat threshold (F2,45 ¼ 5.10; p ¼ 0.01). A significant effect of time (F2,45 ¼ 9.42; p < 0.001) and of limb (F1,46 ¼ 4.78; p ¼ 0.035) for pain intensity during SLR, and a significant effect of time (F2,45 ¼ 3.65; p ¼ 0.034) for pain intensity during PPT. Conclusion: Gliding and tensioning had similar and positive effects for flexibility in the mobilized limb, but tensioning was superior for the non-mobilized limb. Gliding was superior to tensioning for pressure pain and heat thresholds.publishe

The protist Trichomonas vaginalis harbors multiple lineages of transcriptionally active Mutator-like elements

<p>Abstract</p> <p>Background</p> <p>For three decades the <it>Mutator </it>system was thought to be exclusive of plants, until the first homolog representatives were characterized in fungi and in early-diverging amoebas earlier in this decade.</p> <p>Results</p> <p>Here, we describe and characterize four families of <it>Mutator</it>-like elements in a new eukaryotic group, the Parabasalids. These <b><it>T</it></b><it>richomonas </it><b><it>v</it></b><it>aginalis </it><it><b>Mu</b>tator- <b>l</b>ike </it><it><b>e</b>lements</it>, or <it>TvMULEs</it>, are active in <it>T. vaginalis </it>and patchily distributed among 12 trichomonad species and isolates. Despite their relatively distinctive amino acid composition, the inclusion of the repeats <it>TvMULE1</it>, <it>TvMULE2</it>, <it>TvMULE3 </it>and <it>TvMULE4 </it>into the <it>Mutator </it>superfamily is justified by sequence, structural and phylogenetic analyses. In addition, we identified three new <it>TvMULE</it>-related sequences in the genome sequence of <it>Candida albicans</it>. While <it>TvMULE1 </it>is a member of the <it>MuDR </it>clade, predominantly from plants, the other three <it>TvMULEs</it>, together with the <it>C. albicans </it>elements, represent a new and quite distinct <it>Mutator </it>lineage, which we named <it>TvCaMULEs</it>. The finding of <it>TvMULE1 </it>sequence inserted into other putative repeat suggests the occurrence a novel TE family not yet described.</p> <p>Conclusion</p> <p>These findings expand the taxonomic distribution and the range of functional motif of <it>MULEs </it>among eukaryotes. The characterization of the dynamics of <it>TvMULEs </it>and other transposons in this organism is of particular interest because it is atypical for an asexual species to have such an extreme level of TE activity; this genetic landscape makes an interesting case study for causes and consequences of such activity. Finally, the extreme repetitiveness of the <it>T. vaginalis </it>genome and the remarkable degree of sequence identity within its repeat families highlights this species as an ideal system to characterize new transposable elements.</p

Gellan gum-based hydrogels support the recreation of the dermal papilla microenvironment

The dermal papilla (DP), a specialized compartment within the hair follicle, regulates hair growth. However, human DP cells rapidly lose their inductivity in 2D-culture given the loss of positional and microenvironmental cues. Spheroids have been capable of recreating the 3D intercellular organization of DP cells, however, DP cell-matrix interactions are poorly represented. Considering the specific nature of the DP's extracellular matrix (ECM), we functionalized gellan gum (GG) with collagen IV-(HepIII) or fibronectin-(cRGDfC) derived peptide sequences to generate a 3D environment in which the phenotype and physiological functions of DP cells are restored. We further tuned the stiffness of the microenvironments by varying GG amount. Biomimetic peptides in stiffer hydrogels promoted the adhesion of DP cells, while each peptide and amount of polymer independently influenced the type and quantity of ECM proteins deposited. Furthermore, although peptides did not seem to have an influence, stiffer hydrogels improved the inductive capacity of DP cells after short term culture. Interestingly, independently of the peptide, these hydrogels supported the recapitulation of basic hair morphogenesis-like events when incorporated in an organotypic human skin in vitro model. Our work demonstrates that tailored GG hydrogels support the generation of a microenvironment in which both cell-ECM and cell-cell interactions positively influence DP cells towards the creation of an artificial DP.Authors would like to acknowledge the financial support from the Consolidator Grant “ECM_INK” (ERC-2016-COG-726061) and from FCT/MCTES (Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior) through the PD/59/2013, PD/BD/113800/2015 (Carla Abreu), PD/169/2013 (Manuela Lago) and IF/00945/2014 (Alexandra Marques) grants. The authors also appreciate the support given by the FSE/POCH (Fundo Social Europeu through the Programa Operacional do Capital Humano) under the scope of the NORTE-08-5369-FSE-000037 grant (Manuela Lago)

Peptide extract from spent yeast improves resistance of Saccharomyces cerevisiae to oxidative stress

Yeast cells face various stress factors during industrial fermentations, since they are exposed to harsh environmental conditions, which may impair biomolecules productivity and yield. In this work, the use of an antioxidant peptide extract obtained from industrial spent yeast was explored as supplement for Saccharomyces cerevisiae fermentation to prevent a common bottleneck: oxidative stress. For that, a recombinant yeast strain, producer of β-farnesene, was firstly incubated with 0.5 and 0.7 g/L peptide extract, in the presence and absence of hydrogen peroxide (an oxidative stress inducer), for 1–5 h, and then assayed for intracellular reactive oxygen species, and growth ability in agar spot assays. Results showed that under 2 mM H2O2, the peptide extract could improve cells growth and reduce reactive oxygen species production. Therefore, this antioxidant effect was further evaluated in shake-flasks and 2-L bioreactor batch fermentations. Peptide extract (0.7 g/L) was able to increase yeast resistance to the oxidative stress promoted by 2 mM H2O2, by reducing reactive oxygen species levels between 1.2- and 1.7-fold in bioreactor and between 1.2- and 3-fold in shake-flask fermentations. Moreover, improvements on yeast cell density of up to 1.5-fold and 2-fold, and on biomolecule concentration of up to 1.6-fold and 2.8-fold, in bioreactor and shake-flasks, respectively, were obtained. Thus, culture medium supplementation with antioxidant peptide extracted from industrial spent yeast is a promising strategy to improve fermentation performance while valuing biomass waste. This valorization can promote a sustainable and eco-friendly solution for the biotechnology industry by the implementation of a circular economy model.info:eu-repo/semantics/publishedVersio

neurodegenerative diseases, tissue engineering and regenerative medicine

Funding This work was supported by grants from Fundação para a Ciência e Tecnologia (FCT) (SFRH/BD/148771/2019, 2021.05914.BD, PTDC/BTM-MAT/4738/2020), and also from the European Research Council—ERC Starting Grant (848325).A bio-inspired strategy has recently been developed for camouflaging nanocarriers with biomembranes, such as natural cell membranes or subcellular structure-derived membranes. This strategy endows cloaked nanomaterials with improved interfacial properties, superior cell targeting, immune evasion potential, and prolonged duration of systemic circulation. Here, we summarize recent advances in the production and application of exosomal membrane-coated nanomaterials. The structure, properties, and manner in which exosomes communicate with cells are first reviewed. This is followed by a discussion of the types of exosomes and their fabrication methods. We then discuss the applications of biomimetic exosomes and membrane-cloaked nanocarriers in tissue engineering, regenerative medicine, imaging, and the treatment of neurodegenerative diseases. Finally, we appraise the current challenges associated with the clinical translation of biomimetic exosomal membrane-surface-engineered nanovehicles and evaluate the future of this technology.publishersversionpublishe

Obesity, acute kidney injury and mortality in patients with sepsis: a cohort analysis

Although the prognostic effect of obesity has been studied in critically ill patients its impact on outcomes of septic patients and its role as a risk factor for acute kidney injury (AKI) is not consensual. We aimed to analyze the impact of obesity on the occurrence of AKI and on in-hospital mortality in a cohort of critically ill septic patients. This study is retrospective including 456 adult patients with sepsis admitted to the Division of Intensive Medicine of the Centro Hospitalar Lisboa Norte (Lisbon, Portugal) between January 2008 and December 2014. Obesity was defined as a body mass index of 30 kg/m2 or higher. The Kidney Disease Improving Global Outcomes classification was used to diagnose and classify patients developing AKI. AKI occurred in 87.5% of patients (19.5% with stage 1, 22.6% with stage 2 and 45.4% with stage 3). Obese patients developed AKI more frequently than non-obese patients (92.8% versus 85.5%, p = .035; unadjusted OR 2.2 (95% CI: 1.04-4.6), p = .039; adjusted OR 2.31 (95% CI: 1.07-5.02), p = .034). The percentage of obese patients, however, did not differ between AKI stages (stage 1, 25.1%; stage 2, 28.6%; stage 3, 15.4%; p = .145). There was no association between obesity and mortality (p = .739). Of note, when comparing AKI patients with or without obesity in terms of in-hospital mortality there were also no significant differences between those groups (38.4% versus 38.4%, p = .998). Obesity was associated with the occurrence of AKI in critically ill patients with sepsis; however, it was not associated with in-hospital mortality.info:eu-repo/semantics/publishedVersio

Drivers of change: How the food system of the Lisbon Metropolitan Area is being shaped by activities, initiatives and citizens needs towards a sustainable transition

Food has always been an urban issue. The role of cities in building more sustainable food systems is already recognized and related to other urban domains, such as transport, health, land use planning for agriculture and multifunctional areas, community development, employment generation and waste management. The implications of these on urban planning and practice are however less evident. A proper spatialization of the food system and of its metabolic flows is missing, inhibiting their necessary readings for urban design. This paper addresses this gap. After introducing the concept of food system and discussing its spatial components – production, transformation, distribution, commercialization/consumption and waste management – we expose how a set of food-related activities and initiatives are shaping the Lisbon Metropolitan Area. The socio-ecological metabolic flows established by these operations on the ground and their sustainability impacts are established, based on the analysis of five municipalities: Lisbon, Oeiras, Alcochete, Palmela and Montijo. The results reveal how food is already an opportunity for the creation of jobs, healthy food markets and the promotion of land productivity, in particular on a micro scale. The paper recognizes the importance of localized food systems and their particular metabolic flows, capable of boosting opportunities to overcome physical and social obstacles and to increase the possibilities for urban planning to target the urban food system on a wider scale. Finally, it concludes that the overall food system of a metropolitan area is more than the sum of the several food systems operating in that same region