Characterization of chip-size electrically-small antennas for smart wireless biomedical devices

The new requirements for smarter and smaller biomedical microsystems demand for new integration technologies, including antenna integration. This can be solved with the use of microfabrication technologies, allowing the fabrication of chip-size antennas that may be placed on top of silicon wafers. However, due to their ultra-small physical dimensions and special operating conditions (e.g., covered with body tissue phantoms), antenna characterization requires the use of auxiliary custom-made transitions between antenna and test equipment, which are much larger than the antennas under test. Since electrically small antennas show also very small gain, the use of test boards may carry a significant impact on the antenna's characteristics. This paper presents a methodology used to investigate the performance of chip-size 3D antennas (500x500x500 mu m(3)) designed to operate inside the human body in the frequency band 1-8 GHz.This work was supported by Portuguese Foundation for Science and Technology: FCT-PTDC/EEI-TEL/2881/2012, Programa Operacional Temático Fatores de Competitividade (COMPETE) and Fundo Comunitário Europeu FEDER.info:eu-repo/semantics/publishedVersio

60 GHz on-chip antenna array with efficiency improvement using 3D microfabrication technology

The 55-65 GHz band has very interesting characteristics, such as allowing high-bandwidth communications and improved security (due to high absorption). From the antenna point of view, it also has the interesting feature of allowing the fabrication of very small antennas. Because they're so small, these antennas can be placed directly on-chip. However, silicon is a high loss material at such high frequencies. This paper proposes a solution to obtain one antenna array with improved efficiency. Instead of designing the antennas on top of silicon, 3D antennas are designed to lie above the silicon substrate.This work was supported by Portuguese Foundation for Science and Technology: FCT-PTDC/EEI-TEL/2881/2012, Programa Operacional Temático Fatores de Competitividade (COMPETE) and Fundo Comunitário Europeu FEDER.info:eu-repo/semantics/publishedVersio

RF CMOS Wireless Implantable Microsystem for Sacral Roots Stimulation with On-Chip Antenna and Far-Field Wireless Powering

The use of heterogeneous integration technologies is the path for the development of further miniaturized, smarter, and energy autonomous microdevices, which are required to tackle the challenge of monitoring and/or control the health condition of everyone, everywhere. The interaction with human body requires the use of flexible materials, while the electronic component are based on rigid materials, like silicon substrates. Also, once inside the human body, it is desirable to have a wireless link for data communication, as well for RF powering, using energy harvesting techniques or dedicated powering RF links. This paper shows the design of an implantable microsystem to be used for functional electrical stimulation of sacral roots. The proposed system includes flexible electrodes, integrated with an RF CMOS chip, which is powered by a wireless link through an efficient on-chip antenna.This work was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/62608/2009), FCT-PTDC/EEI-TEL/2881/2012, Programa Operacional Temático Fatores de Competitividade (COMPETE) and Fundo Comunitário Europeu FEDER.info:eu-repo/semantics/publishedVersio

Consistency analysis of a nonbirefringent Lorentz-violating planar model

In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor $\kappa_{\mu\nu}$. The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for $0\leq\kappa_{00}<1$. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a $\lambda|\varphi|^{4}-$Higgs field supports compactlike vortex configurations.Comment: 11 pages, revtex style, final revised versio

Dual equivalence in models with higher-order derivatives

We introduce a class of higher-order derivative models in (2,1) space-time dimensions. The models are described by a vector field, and contain a Proca-like mass term which prevents gauge invariance. We use the gauge embedding procedure to generate another class of higher-order derivative models, gauge-invariant and dual to the former class. We show that the results are valid in arbitrary (d,1) space-time dimensions when one discards the Chern-Simons and Chern-Simons-like terms. We also investigate duality at the quantum level, and we show that it is preserved in the quantum scenario. Other results include investigations concerning the gauge embedding approach when the vector field couples with fermionic matter, and when one adds nonlinearity.Comment: RevTex4, 14 pages; new version includes duality at the quantum level, and new references. To be published in J. Phys.

Dual embedding of the Lorentz-violating electrodinamics and Batalin-Vilkovisky quantization

Modifications of the electromagnetic Maxwell Lagrangian in four dimensions have been considered by some authors. One may include an explicit massive term (Proca) and a topological but not Lorentz-invariant term within certain observational limits. We find the dual-corresponding gauge invariant version of this theory by using the recently suggested gauge embedding method. We enforce this dualisation procedure by showing that, in many cases, this is actually a constructive method to find a sort of parent action, which manifestly establishes duality. We also use the gauge invariant version of this theory to formulate a Batalin-Vilkovisky quantization and present a detailed discussion on the excitation spectrum.Comment: 8 page

Fabrication of pre-structured substrates and growth of CIGS micro-absorbers

Second-generation thin-film Cu(In, Ga)Se2 (CIGS) solar cells are a well-established photovoltaic technology with a record power conversion efficiency of 23.6%. However, their reliance on critical raw materials, such as In and Ga, requires new approaches to reduce the amount of critical raw materials employed. The micro-concentrator concept involves the combination of thin-film photovoltaic technology with concentrator photovoltaic technology. This approach reduces the size of the solar cell to the micrometer range and uses optical concentration to collect sunlight from a larger area, focusing it onto micro solar cells. This work is devoted to the development of a process for manufacturing pre-structured substrates with regular arrays of holes with 200 and 250 μm diameters inside a SiOx insulating matrix. Subsequently, a Cu–In–Ga precursor is deposited by sputtering, followed by photoresist lift-off and the application of a Cu–In–Ga thermal annealing at 500 ◦C to improve precursor quality and assess pre-structured substrate stability under elevated temperatures. Finally, a two-stage selenization process leads to the formation of CIGS absorber micro-dots. This study presents in detail the fabrication process and explores the feasibility of a bottom-up approach using pre-structured substrates, addressing challenges encountered during fabrication and providing insights for future improvements in CIGS absorber materials.This research was funded by Fundação para a Ciência e a Tecnologia (FCT), PhD Scholarship number 2020.06063BD and partially funded by the UIDB/04650/2020 Strategic Project of the Physics Center of the University of Minho and Porto

Criança imigrante num serviço de pediatria: que problemas sociais?

Introdução: A zona suburbana de influência do hospital serve uma população que abrange imigrantes oriundos de países em vias de desenvolvimento. Objectivos: Caracterizar a população pediátrica imigrante internada e referenciada ao serviço social e compará-la com a restante população portuguesa. Material e Métodos: Estudo prospectivo realizado entre Novembro de 2004 a Março de 2005. Analisaram-se dados demográficos, sócio-económicos, motivo de internamento e de referenciação ao serviço social e encaminhamento da situação. Resultados: De um total de 35 crianças observadas, 22 (62,8%) eram filhas de imigrantes, 45% com menos de 12 meses, a maioria do sexo feminino (54,5%), raça negra (81,8%) e com más condições sócio-económicas (72,3%). A maioria dos pais (72,7%) era oriunda de um País Africano de Língua Oficial Portuguesa (PALOP) e 58,3% não estavam legalizados no nosso país. A maioria (81,3%) tinha médico de família atribuído. Dezanove (85,7%) foram internados por doença orgânica tendo o problema social sido detectado durante o internamento. Os problemas sociais identificados foram pobreza (9), negligência (7), agressão física (3), abandono (2), maus-tratos psicológicos (1), abuso sexual (1) e outras situações (3). Cinco crianças foram orientadas para a Comissão de Protecção de Menores e uma para o Tribunal. Foram ainda prestados apoios económicos (6) e sociais (4) pelo hospital e pelo Centro de Saúde (1). Comparativamente à população portuguesa avaliada, os problemas sociais são mais frequentes na população imigrante (20% vs 7,5%; p =0,001), com predomínio nas crianças de origem africana (81,8% versus 15,4%; p =0,00). Embora não seja estatisticamente significativo a pobreza (37,5% vs 26,6%% p =0,313) e agressão física (13% vs 8,3% p =0,313) são mais frequentes nos imigrantes, contrariamente à população nacional, que o problema social mais frequente foi a negligência (33,3% vs 29% p =0,313). Discussão: O número crescente de filhos de imigrantes e as deficiências socio económicas desta população, levantam importantes questões relacionadas com a prestação de cuidados sociais a cidadãos estrangeiros, gerando a necessidade de criação de estruturas de apoio social de forma a permitir a sua melhor integração na sociedade

Up-scaling Mate Marote: a university-industry interaction experience

The new digital era opens up great possiblilities in education. Mate Marote is a platform including activities and educational games for massive scale interventions. Recent creation of Fundación Sadosky, has favored the collaboration between industry and academia in projects involving novel methods and ideas with big scale software platforms which require experience in architecture and high-end software development. The collaboration established showed exceptional conditions for the mutual benefit: the incorporation of academic research in educational neuroscience in the industry and the transference of well-established methodology and software development experience in the academic environment.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Lack of detrimental effects of ocean acidification and warming on proximate composition, fitness and energy budget of juvenile Senegalese sole (Solea senegalensis)

Funding Information: This work was supported by the FISHBUDGET - Effects of climate change on marine fish energy budgets ( PTDC/BIA-BMA/28630/2017 ) - project; benefited from the strategic project UIDB/04292/2020 awarded to MARE and the project LA/P/0069/2020 granted to the Associate Laboratory ARNET funded by the FCT / Ministério da Ciência, Tecnologia e Ensino Superior (MCTES), and through other national funds ( UIDB/50006/2020 ). The authors thank the Sparos, Lda company for providing the fish feed, and EPPO aquaculture research station team (Olhão) for providing juvenile fish for trails. FCT supported the contract of HO (through the FISHBUDGET project), PA (in the framework of CEECIND/01739/2017 ) and TR ( DL57/2016/CP1479/CT0023 ). Funding Information: This work was supported by the FISHBUDGET - Effects of climate change on marine fish energy budgets (PTDC/BIA-BMA/28630/2017) - project; benefited from the strategic project UIDB/04292/2020 awarded to MARE and the project LA/P/0069/2020 granted to the Associate Laboratory ARNET funded by the FCT/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES), and through other national funds (UIDB/50006/2020). The authors thank the Sparos, Lda company for providing the fish feed, and EPPO aquaculture research station team (Olhão) for providing juvenile fish for trails. FCT supported the contract of HO (through the FISHBUDGET project), PA (in the framework of CEECIND/01739/2017) and TR (DL57/2016/CP1479/CT0023). Publisher Copyright: © 2022 The AuthorsRising levels of atmospheric carbon dioxide (CO2) are driving ocean warming and acidification, which may negatively affect the nutritional quality and physiological performance of commercially important fish species. Thus, this study aimed to evaluate the effects of ocean acidification (OA; ΔpH = −0.3 units equivalent to ΔpCO2 ~ +600 μatm) and warming (OW; ΔT = +4 °C) (and combined, OAW) on the proximate composition, fitness and energy budget of juvenile Senegalese sole (Solea senegalensis). After an exposure period of 75 days, growth (G), metabolism (R) and excretion (faecal, F and nitrogenous losses, U) were assessed to calculate the energy intake (C). Biometric and viscera weight data were also registered to determine animal fitness. Overall, the proximate composition and gross energy were not significantly affected by acidification and warming (alone or in combination). Weight gain, maximum and standard metabolic rates (MMR and SMR, respectively), aerobic scope (AS) and C were significantly higher in fish subjected to OA, OW and OAW than in CTR conditions. Furthermore, the highest relative growth rates (RGR), specific growth rates in terms of wet weight (SGRw) and protein (SGRp), as well as feed efficiencies (FE) occurred in fish submitted to OW and OAW. On the other hand, fish exposed to CTR conditions had significantly higher feed conversion ratio (FCR) and ammonia excretion rate (AER) than those exposed to simulated stressors. Regarding energy distribution, the highest fraction was generally allocated to growth (48–63 %), followed by excretion through faeces (36–51 %), respiration (approximately 1 %) and ammonia excretion (0.1–0.2 %) in all treatments. Therefore, ocean warming and acidification can trigger physiological responses in juvenile Senegalese sole, particularly in their energy budget, which can affect the energy flow and allocation of its population. However, and in general, this species seems highly resilient to these predicted ocean climate change stressors.publishersversionpublishe