Browsing by Author "Gomes, A."
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- Detecting and reducing interference in 3G and beyond wireless access networksPublication . Gomes, A.; Sousa, M.; Vieira, Pedro; Rodrigues, A.As wireless access networks evolve, addressing the growing subscribers demand, their complexity has been increasing too. To manage it, Mobile Network Operator (MNO)s rely more often on automatic methods, such as network planning, optimization and maintenance. In this regard, this study focuses on the development of a intra-Radio Access Technology (RAT) coverage optimization and interference reduction algorithm, applying Self-Organizing Networks (SON) concepts. A Genetic Algorithm (GA) was used to optimize multiple antenna tilt parameters, based on Drive Test (DT) measurements and network configuration. This study was applied to the 3rd Generation (3G) technology, nonetheless, it can be adapted to other RAT. It was tested, with both single and multiple cells optimization, resulting in a Radio Frequency (RF) condition improvement. In an urban scenario, the simultaneous optimization of several cells, resulted in a 50th percentile Received Signal Code Power (RSCP) and Energy per Chip on Spectral Noise Density (Ec/No) distributions improvement of 7 dB and 3 dB, respectively. Moreover, the joint optimization of the Electrical Downtilt (EDT) and Mechanical Downtilt (MDT) proved insignificant advantages over just the EDT optimization.
- GASMoC method: a phenol-free technique to detect acid-fast bacilliPublication . Gomes, A.; Amaral, P.; Santos, R.; Santos, S.; Tortosa, F.; Mendonça, Paula; Marques-Ramos, AnaThe genre Mycobacterium includes a series of pathological species, such as M. tuberculosis, which is important for pathology laboratories to detect for a correct diagnosis. The Ziehl-Neelsen technique (ZNT) is the most common histochemical method used to detect these bacilli and uses a heated mixture of carbol-fuchsine, which contains basic fuchsine and phenol. Whereas the former component is responsible for the pinkish staining of acid-fast mycobacteria, the role of phenol is not completely understood and it has been suggested that its exclusion does not impact the detection ability of the ZNT. Since phenol is highly toxic and induces several injuries, the goal of this study is to determine the detection capacity of mycobacteria through a method that excludes the use of phenol. Accordingly, the GASMoC method, a modified ZNT that employs a solution of aqueous basic fuchsine heated at 37 °C, was tested on histological samples positive for mycobacteria and the results were compared to that of the ZNT. Data demonstrated that the GASMoC method was able to detect acid-fast bacilli (AFB) in all analyzed cases. Remarkably, microscopic inspection of mycobacteria was easier when the GASMoC method was applied. In conclusion, our study demonstrates that AFB detection does not require phenol and that the GASMoC method, a phenol-free technique, may substitute the ZNT in pathology laboratories.
- Impacto do uso de fucsina básica aquosa na detecção de bacilos álcool-ácido resistentesPublication . Gomes, A.; Amaral, P.; Santos, R.; Santos, S.; Tortosa, F.; Mendonça, Paula; Marques-Ramos, AnaTuberculose - Infeção com maior mortalidade a nível mundial em 2016, causada pelo bacilo de Kock ou Mycobacterium tuberculosis. Técnica de Ziehl-Neelsen (ZN) - Evidenciar bacilos álcool-ácido resistentes (BAAR). Carbol-fucsina - Solução composta por fenol e fucsina básica. Objetivo geral do estudo - Determinar a capacidade de deteção da técnica de Ziehl-Neelsen sem o uso de fenol. Hipótese investigacional - Tendo por base dois estudos já realizados, é possível suprimir o fenol na técnica de ZN, através do uso de fucsina básica aquosa, sem afetar a capacidade de deteção de BAAR.
- Método GASMoC: uma técnica para detetar bacilos álcool ácido-resistentes sem fenolPublication . Gomes, A.; Amaral, P.; Santos, R.; Santos, S.; Tortosa, F.; Mendonça, Paula; Marques-Ramos, AnaA técnica de Ziehl-Neelsen (ZN) permite detetar bacilos álcoolácido resistentes (BAAR), tal como Mycobacterium tuberculosis (agente causador da tuberculose). Nesta técnica, a carbol-fucsina (CF) penetra a parede das BAAR conferindo-lhes uma tonalidade rosa que é mantida quando utilizada uma solução descorante, devido ao envelope celular que lhes confere resistência álcool-ácida2. Assim, as BAAR são demonstradas a rosa sobre um fundo azul. A CF implica o uso de fenol que liberta vapores, cuja inalação pode resultar em graves efeitos para a sua saúde a curto e a longo prazo. Alguns autores comprovaram a capacidade da fucsina básica aquosa (FBA) aquecida, como alternativa, para corar BAAR. Assim sendo, pretende-se com o presente estudo determinar a capacidade de deteção da técnica de Ziehl-Neelsen sem o uso de fenol.