Study of Freezing and Defrosting Effects on Complex Permittivity of Biological Tissues

In this letter we study the effect of freezing and defrosting on the dielectric properties of biological tissues. The electromagnetic characterization of tissues at microwave frequencies is crucial for the development of microwave-based biomedical devices. These measurements are often not practical, as tissue degradation restricts the time available between tissue excision and dielectric measurements. For this reason, measurement of tissues that underwent freezing and defrosting may provide researchers with more flexibility in setting measurement campaigns, thus speeding up the development of microwave-based biomedical devices. To this end, this letter presents dielectric measurement on frozen and defrosted tissue, which translates into the following objectives: first, investigate if the dielectric properties of defrosted tissues depend on frozen storage time; second, determine if defrosted tissue dielectric properties differ from those of fresh tissues. As a result, we measure the dielectric properties of ten samples of chicken muscle, bovine liver, and bovine fat, each before and after freezing (up to 14 days) and defrosting. The measurements are performed with the open-ended coaxial probe method at the frequency band of 0.5–8.5 GHz. We observe a slight increase—less than 10%—in complex permittivity of high-water-content tissues (muscle and liver) after defrosting, and negligible effect on fat tissues.info:eu-repo/semantics/acceptedVersio

Role of 99mTc-Sulesomab Immunoscintigraphy in the Management of Infection following Deep Brain Stimulation Surgery

Infection constitutes a serious adverse event in patients submitted to deep brain stimulation, often leading to removal of the device. We set to evaluate the potential role of immunoscintigraphy with 99mTc-labelled antigranulocyte antibody fragments (99mTc-sulesomab) in the management of infection following DBS. 99mTc-sulesomab immunoscintigraphy seems to correlate well with the presence and extent of infection, thus contributing to differentiate between patients who should remove the hardware entirely at presentation and those who could undergo a more conservative approach. Also, 99mTc-sulesomab immunoscintigraphy has a role in determining the most appropriate timing for reimplantation. Finally, we propose an algorithm for the management of infection following DBS surgery, based on the results of the 99mTc-sulesomab immunoscintigraphy

Development of a Transmission-Based Open-Ended Coaxial-Probe Suitable for Axillary Lymph Node Dielectric Measurements

We assess the feasibility of a transmission-based open-ended coaxial-probe for tissue dielectric properties estimation. The ultimate goal is to use it for axillary lymph node dielectric measurement, which is not trivial when applying the state-of-the-art reflection-based open-ended coaxial-probe. The proposed technique consists in placing the material under test between two opposite open-ended coaxial-probes and record the transmission coefficient. We numerically assess three coaxial probe configurations, in order to ensure adequate transmission and sensing volume. The final setup allows for enough propagation through a 5mm sample (which will be sufficient for the measurements of axillary lymph nodes), while confining the sensing volume to the region of interest. Experimental tests on two materials of different permittivity ranges showed good agreement between the measured and numerical transmission coefficient. Moreover, we observed that the transmission coefficient can highlight the contrast between materials with different dielectric properties. The promising initial results motivate the further application of the method to the case of axillary lymph nodes.info:eu-repo/semantics/acceptedVersio

CHLAMYDIA TRACHOMATIS NUMA CONSULTA DE INFECÇÕES SEXUALMENTE TRANSMISSÍVEIS – ESTUDO RETROSPECTIVO DE QUATRO ANOS (2006-2009)

Chlamydia trachomatis (Ct) is often responsible for an asymptomatic genital infection and represents a major public health problem when untreated. The authors objective was to determinate the Ct genital infection prevalence in a Sexual transmitted infections (STIs) clinic, and to perform an analysis of different variables. It was a retrospective study of all the patients with a Ct infection, observed in the STIs clinic of the Dermatology and Venereology department of Curry Cabral Hospital, between January 2006 and December 2009. The diagnosis was confirmed by Nucleic acid amplification technique. An infection prevalence of 10,5% was found (81 patients with infection in 771 tested). In the 81 infected patients, statistic differences were found in the medium age between male and female patients (male=28,9 vs female=24,3) p=0,018; in the number of different sexual partners in the last 6 months (men= 3,32 vs female=1,5) p=0,009; and in the time in weeks between the beginning of symptoms and the diagnosis (male=2,65 vs female=6,64) p=0,032. The patients with Human immunodeficiency virus (HIV) co-infection had a superior number of different sexual partners in the last 6 months comparing with the non HIV p=0,003. We concluded that in our patients there were demographic, behavioral and clinical differences between male and female, and between HIV and non HIV. Besides that, the elevated prevalence that was found reinforces the importance of the programs instituted for early diagnosis of Ct infection.A infecção genital por Chlamydia trachomatis (Ct) é frequentemente assintomática e quando não tratada precocemente constitui um problema major de saúde pública. Os autores realizaram um estudo cujo objectivo foi determinar a prevalência de infecção genital por Ct numa consulta de Infecções Sexualmente Transmissíveis (ISTs) e realizar uma análise de diferentes variáveis. Para tal foi realizado um estudo retrospectivo dos doentes com diagnóstico de infecção por Ct confirmado por técnica de amplificação de ácidos nucleicos, observados na consulta de ISTs do Serviço de Dermatologia e Venereologia do Hospital Curry Cabral entre Janeiro de 2006 e Dezembro de 2009. Encontrou-se uma prevalência de infecção de 10,5% (81 doentes com infecção genital por Ct em 771 indivíduos testados). Na população com infecção por Ct foram encontradas diferenças com significado estatístico entre o sexo masculino e feminino na idade média dos doentes (homens=28,9 vs mulheres=24,3) p= 0,018; no número de companheiros sexuais nos últimos 6 meses (homens=3,32 vs mulheres=1,50) p=0,009; e no tempo em semanas decorrido entre o início dos sintomas e o diagnóstico (homens=2,65 vs mulheres=6,64) p= 0,032. Os doentes com co-infecção pelo Vírus da Imunodeficiência Humana (VIH) tinham um maior número de companheiros sexuais nos últimos 6 meses do que os não VIH p=0,003. Assim, existem diferenças demográficas, comportamentais e clínicas entre o sexo masculino e feminino e entre a população VIH e não VIH. Além disso, a elevada prevalência de infecção por Ct justifica os programas de diagnóstico precoce instituídos

TINEA CAPITIS NO ADULTO – UM DIAGNÓSTICO A CONSIDERAR?

Tinea capitis, a dermatophytic infection of the scalp, is rare in adults, even in geographic areas with high prevalence rates. The source of the infection is usually a straight contact with cohabitants, and in adults it is mainly, but not always, associated with immunosuppression. A careful anamnesis and a complete physical examination are crucial to establish tinea capitis as a clinical diagnostic hypothesis in order to promptly collect samples for mycological studies, avoiding unnecessary additional studies or incorrect prescriptions. The authors report three cases of tinea capitis in adults – two cases caused by Microsporum audouinii and the other one caused by Trichophyton soudanense. The cases are iconographically depicted and a brief review of the relevant literature is presented.KEYWORDS – Adulto;Tinea Capitis; Microsporum; Trichophyton; Mycological Typing Techniques.A tinea capitis, uma infecção por fungos dermatófitos do couro cabeludo, é uma patologia rara no adul- to, mesmo em áreas geográficas onde a doença é prevalente. Nestes casos está muitas vezes, mas não exclusivamen- te, associada a imunodepressão e habitualmente surge por exposição ao agente infeccioso em contactantes próximos. São fundamentais uma história clínica e um exame objectivo minuciosos que permitam equacionar a tinha do couro cabeludo como hipótese diagnóstica e proceder à colheita de amostras para exame micológico. Esta metodologia pode evitar a realização de exames complementares exaustivos ou a prescrição de tratamentos inadequados. Os autores descrevem três casos de tinea capitis em mulheres adultas – dois casos de infecção por Microsporum au- douinii e um caso por Trichophyton soudanense. É apresentado o registo iconográfico dos casos e é efectuada breve revisão da literatura.PALAVRAS-CHAVE – Adulto, Dermatófitos; Tinea Capitis; Micologia

Aprendizagem autorregulada da matemática: uma proposta de tutor virtual

We are developing an online educational software  based on self-regulation theory consisting of a virtual tutor and three-dimensional visualizations that will allow the student to learn, develop and consolidate the concepts presented in class, by allowing him to, in real time as the task is being performed, understand his mistakes, through the virtual tutor's intervention. This digital agent follows all the student´s steps in the background, appearing only when necessary in diverse and playful ways. In order to validate this software we will look at the domain of GM4 contents – Geometry and Measures – and verify the Polya strategies for problem-solving.Atendendo ao identificado e quantificado fraco desempenho dos alunos a Matemática, desenhamos um software educativo online — assente na teoria da autorregulação — integrando um tutor virtual e visualizações tridimensionais, dirigido a alunos do 4º ano do Ensino Básico.  Pretende-se constituir uma nova ferramenta de trabalho/estudo completa que permite ao aluno aprender, desenvolver e consolidar os conceitos apresentados na sala de aula, podendo, em tempo real e durante a execução das tarefas, perceber os erros cometidos através da intervenção do tutor virtual que explica e justifica. Este agente digital permitirá observar todo o processo executado pelo aluno, de forma invisível, surgindo apenas quando necessário, de forma lúdica e diversificada.  O nosso projeto visa duas fases cruciais: a validação do protótipo (implicando 2 turmas do 4º ano) já realizada com resultados preliminares auspiciosos informalmente comprovados; e aperfeiçoamento/desenvolvimento do software (versão final), para verificação e confirmação da sua potencialidade educativa (incluindo 10 turmas do 4º ano de escolaridade).  Para verificação e validação do valor educativo deste software — versão final  operacional, passível de desenvolvimento imediato na aplicação a outros temas e anos de escolaridade — abordaremos o domínio de conteúdos GM4 (geometria e medidas) e verificaremos as estratégias de resolução de problemas (estratégias de Polya) face ao tema em questão. Os resultados da análise destas estratégias de resolução de problemas serão posteriormente relacionados com as estratégias autorregulatórias. A amostra será constituída por 10 turmas de 4º ano de escolaridade. A recolha de dados será feita, sobretudo, a partir do próprio software, de uma base de dados a disponibilizar aos docentes das respetivas turmas, sendo esses dados de natureza quantitativa e qualitativa. Em termos metodológicos, trata-se de uma investigação de desenvolvimento organizada em fases e sub-estudos, cada uma e cada um socorrendo-se dos métodos e estratégias adequadas, daqui resultando uma metodologia multivariada

Power loss of FZG gears lubricated with wind turbine gear oil using ionic liquid additive

This work presents a study of the tribological behaviour of a mineral fully-formulated wind turbine gear oil additised with [BMP][NTf2] ionic liquid. The target application are the wind turbine gearboxes, thus the fully formulated oil with and without ionic liquid additive was tested in a rolling bearings test rig to measure the thrust rolling bearing torque loss and was also tested in a FZG gear test rig to measure the gears torque loss at operating conditions similar to the observed in a wind turbine gearbox. The results show that a wind turbine gear oil additised with ionic liquid can reduce the torque loss and improve the gearbox efficiency while producing less wear particles as observed in the oil analysis.The authors thank to the Ministry of Science and Innovation (Spain) and to the Foundation for the Promotion in Asturias of the Applied Scientific Research and Technology (FICYT) for supporting this research within the framework of the Research Projects WINDTRIB (DPI2010-18166) and GRUPIN14-023, respectively. The authors thank to Repsol S.A. that provided the wind turbine gear oil. The authors gratefully acknowledge the funding supported by: National Funds through Fundação para a Ciência e a Tecnologia (FCT), under the project EXCL/SEMPRO/ 0103/2012; COMPETE and National Funds through Fundação para a Ciência e a Tecnologia (FCT), under the project Incentivo/EME/LA0022/2014; Quadro de Referência Estratégico Nacional (QREN), through Fundo Europeu de Desenvolvimento Regional (FEDER), under the project NORTE-07-0124-FEDER- 000009 - Applied Mechanics and Product Development; without whom this work would not be possible

Development of an Anthropomorphic Phantom of the Axillary Region for Microwave Imaging Assessment

We produced an anatomically and dielectrically realistic phantom of the axillary region to enable the experimental assessment of Axillary Lymph Node (ALN) imaging using microwave imaging technology. We segmented a thoracic Computed Tomography (CT) scan and created a computer-aided designed file containing the anatomical configuration of the axillary region. The phantom comprises five 3D-printed parts representing the main tissues of interest of the axillary region for the purpose of microwave imaging: fat, muscle, bone, ALNs, and lung. The phantom allows the experimental assessment of multiple anatomical configurations, by including ALNs of different size, shape, and number in several locations. Except for the bone mimicking organ, which is made of solid conductive polymer, we 3D-printed cavities to represent the fat, muscle, ALN, and lung and filled them with appropriate tissue-mimicking liquids. Existing studies about complex permittivity of ALNs have reported limitations. To address these, we measured the complex permittivity of both human and animal lymph nodes using the standard open-ended coaxial-probe technique, over the 0.5 GHz-8.5 GHz frequency band, thus extending current knowledge on dielectric properties of ALNs. Lastly, we numerically evaluated the effect of the polymer which constitutes the cavities of the phantom and compared it to the realistic axillary region. The results showed a maximum difference of 7 dB at 4 GHz in the electric field magnitude coupled to the tissues and a maximum of 10 dB difference in the ALN response. Our results showed that the phantom is a good representation of the axillary region and a viable tool for pre-clinical assessment of microwave imaging technology.info:eu-repo/semantics/publishedVersio