903 resultados para TRICKLING FILTERS
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INTRODUCTION: Mansonelliasis is caused by Mansonella ozzardi. It is widespread in the Amazon region, with a high prevalence. The common exam of thick blood smears stained with Giemsa shows low efficacy levels and has been an obstacle to diagnosing individuals with low blood parasitemia. METHODS: In order to increase diagnosis efficacy, the PCR technique was improved. RESULTS AND CONCLUSIONS: PCR demonstrated the best performance, with sensitivity and negative predictive values (NPV) of 100%, followed by blood filtration through membrane filters, which showed a sensitivity of 88.9% and a NPV of 84.6%, when compared to thick blood smears.
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Modern CMOS radio frequency (RF) Receivers have enabled efficient and increasing applications. The main requirement is to have system in a single chip, in order to minimize area and cost. For the purpose it is required the development of inductorless circuits for the key blocks of an RF receiver. Examples of this key blocks are RC oscillators, RF band pass filters, and Low Noise Amplifiers. The present dissertation presents an inductorless wideband MOSFET-only RF Non-Gyrator Type of Active Inductors with low area, low cost, and very low power, capable of covering the whole WMTS, and ISM, band and intended for biomedical applications. The proposed circuit is based on a floating capacitor connected between two controlled current sources. The first current source, which is controlled by the circuit input voltage, has two objectives: supply current to the capacitor (
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The identification of new and druggable targets in bacteria is a critical endeavour in pharmaceutical research of novel antibiotics to fight infectious agents. The rapid emergence of resistant bacteria makes today's antibiotics more and more ineffective, consequently increasing the need for new pharmacological targets and novel classes of antibacterial drugs. A new model that combines the singular value decomposition technique with biological filters comprised of a set of protein properties associated with bacterial drug targets and similarity to protein-coding essential genes of E. coli has been developed to predict potential drug targets in the Enterobacteriaceae family [1]. This model identified 99 potential target proteins amongst the studied bacterial family, exhibiting eight different functions that suggest that the disruption of the activities of these proteins is critical for cells. Out of these candidates, one was selected for target confirmation. To find target modulators, receptor-based pharmacophore hypotheses were built and used in the screening of a virtual library of compounds. Postscreening filters were based on physicochemical and topological similarity to known Gram-negative antibiotics and applied to the retrieved compounds. Screening hits passing all filters were docked into the proteins catalytic groove and 15 of the most promising compounds were purchased from their chemical vendors to be experimentally tested in vitro. To the best of our knowledge, this is the first attempt to rationalize the search of compounds to probe the relevance of this candidate as a new pharmacological target.
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Purpose: Higher myopic refractive errors are associated with serious ocular complications that can put visual function at risk. There is respective interest in slowing and if possible stopping myopia progression before it reaches a level associated with increased risk of secondary pathology. The purpose of this report was to review our understanding of the rationale(s) and success of contact lenses (CLs) used to reduce myopia progression. Methods: A review commenced by searching the PubMed database. The inclusion criteria stipulated publications of clinical trials evaluating the efficacy of CLs in regulating myopia progression based on the primary endpoint of changes in axial length measurements and published in peerreviewed journals. Other publications from conference proceedings or patents were exceptionally considered when no peer-review articles were available. Results: The mechanisms that presently support myopia regulation with CLs are based on the change of relative peripheral defocus and changing the foveal image quality signal to potentially interfere with the accommodative system. Ten clinical trials addressing myopia regulation with CLs were reviewed, including corneal refractive therapy (orthokeratology), peripheral gradient lenses, and bifocal (dual-focus) and multifocal lenses. Conclusions: CLs were reported to be well accepted, consistent, and safe methods to address myopia regulation in children. Corneal refractive therapy (orthokeratology) is so far the method with the largest demonstrated efficacy in myopia regulation across different ethnic groups. However, factors such as patient convenience, the degree of initial myopia, and non-CL treatments may also be considered. The combination of different strategies (i.e., central defocus, peripheral defocus, spectral filters, pharmaceutical delivery, and active lens-borne illumination) in a single device will present further testable hypotheses exploring how different mechanisms can reinforce or compete with each other to improve or reduce myopia regulation with CLs.
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Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores
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Tese de Doutoramento em Engenharia Eletrónica e de Computadores.
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Dissertação de mestrado integrado em Engenharia Civil
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Fiber membranes prepared from jute fragments can be valuable, low cost, and renewable. They have broad application prospects in packing bags, geotextiles, filters, and composite reinforcements. Traditionally, chemical adhesives have been used to improve the properties of jute fiber membranes. A series of new laccase, laccase/mediator systems, and multi-enzyme synergisms were attempted. After the laccase treatment of jute fragments, the mechanical properties and surface hydrophobicity of the produced fiber membranes increased because of the cross-coupling of lignins with ether bonds mediated by laccase. The optimum conditions were a buffer pH of 4.5 and an incubation temperature of 60 °C with 0.92 U/mL laccase for 3 h. Laccase/guaiacol and laccase/alkali lignin treatments resulted in remarkable increases in the mechanical properties; in contrast, the laccase/2,2-azino-bis-(3-ethylthiazoline-6-sulfonate) (ABTS) and laccase/2,6-dimethoxyphenol treatments led to a decrease. The laccase/ guaiacol system was favorable to the surface hydrophobicity of jute fiber membranes. However, the laccase/alkali lignin system had the opposite effect. Xylanase/laccase and cellulase/laccase combined treatments were able to enhance both the mechanical properties and the surface hydrophobicity of jute fiber membranes. Among these, cellulase/laccase treatment performed better; compared to mechanical properties, the surface hydrophobicity of the jute fiber membranes showed only a slight increase after the enzymatic multi-step processes.
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Lactic acid bacteria (LAB) play a key role in the biopreservation of a wide range of fermented food products, such as yogurt, cheese, fermented milks, meat, fish, vegetables (sauerkraut, olives and pickles), certain beer brands, wines and silage, allowing their safe consumption, which gave to these bacteria a GRAS (Generally Recognised as Safe) status. Besides that, the use of LAB in food and feed is a promising strategy to reduce the exposure to dietary mycotoxins, improving their shelf life and reducing health risks, given the unique mycotoxin decontaminating characteristic of some LAB. Mycotoxins present carcinogenic, mutagenic, teratogenic, neurotoxic and immunosuppressive effects over animals and Humans, being the most important ochratoxin A (OTA), aflatoxins (AFB1), trichothecenes, zearalenone (ZEA), fumonisin (FUM) and patulin. In a previous work of our group it was observed OTA biodegradation by some strains of Pediococcus parvulus isolated from Douro wines. So, the aim of this study was to enlarge the screening of the biodetoxification over more mycotoxins besides OTA, including AFB1, and ZEA. This ability was checked in a collection of LAB isolated from vegetable (wine, olives, fruits and silage) and animal (milk and dairy products, sausages) sources. All LAB strains were characterized phenotypically (Gram, catalase) and genotypically. Molecular characterisation of all LAB strains was performed using genomic fingerprinting by MSP- PCR with (GTG)5 and csM13 primers. The identification of the isolates was confirmed by 16S rDNA sequencing. To study the ability of LAB strains to degrade OTA, AFB1 and ZEA, a MRS broth medium was supplemented with 2.0 g/mL of each mycotoxin. For each strain, 2 mL of MRS supplemented with the mycotoxins was inoculated in triplicate with 109 CFU/mL. The culture media and bacterial cells were extracted by the addition of an equal volume of acetonitrile/methanol/acetic acid (78:20:2 v/v/v) to the culture tubes. A 2 mL sample was then collected and filtered into a clean 2 mL vial using PP filters with 0.45 m pores. The samples were preserved at 4 °C until HPLC analysis. Among LAB tested, 10 strains isolated from milk were able to eliminate AFB1, belonging to Lactobacillus casei (7), Lb. paracasei (1), Lb. plantarum (1) and 1 to Leuconostoc mesenteroides. Two strains of Enterococcus faecium and one of Ec. faecalis from sausage eliminated ZEA. Concerning to strains of vegetal origin, one Lb. plantarum isolated from elderberry fruit, one Lb. buchnerii and one Lb. parafarraginis both isolated from silage eliminated ZEA. Other 2 strains of Lb. plantarum from silage were able to degrade both ZEA and OTA, and 1 Lb. buchnerii showed activity over AFB1. These enzymatic activities were also verified genotypically through specific gene PCR and posteriorly confirmed by sequencing analysis. In conclusion, due the ability of some strains of LAB isolated from different sources to eliminate OTA, AFB1 and ZEA one can recognize their potential biotechnological application to reduce the health hazards associated with these mycotoxins. They may be suitable as silage inoculants or as feed additives or even in food industry.
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OBJECTIVE: The initial site of myocardial infarction (MI) may influence the prevalence of ventricular late potentials (VLP), high-frequency signals, due to the time course of ventricular activation. The prevalence of VLP in a period of more than 2 years after acute MI was assessed focusing on the initially injured wall . METHODS: The prevalence of VLP in a late phase after MI (median of 924 days) in anterior/antero-septal and inferior/infero-dorsal wall lesion was analyzed using signal-averaged electrocardiogram in time domain. The diagnostic performance of the filters employed for analysis on was tested at high-pass cut-off frequencies of 25 Hz, 40 Hz and 80 Hz. RESULTS: The duration of the ventricular activation and its terminal portion were larger in inferior than anterior infarction, at high-pass cut-off frequencies of 40 Hz and 80 Hz. In patients with ventricular tachycardia, these differences were more remarked. The prevalence of ventricular late potentials was three times greater in inferior than anterior infarction. CONCLUSION: Late after myocardial infarction, the prevalence and the duration of ventricular late potentials are greater in lesions of inferior/infero-dorsal than anterior/antero-septal wall confirming their temporal process, reflecting their high-frequency content.
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This project was funded under the Applied Research Grants Scheme administered by Enterprise Ireland. The project was a partnership between Galway - Mayo Institute of Technology and an industrial company, Tyco/Mallinckrodt Galway. The project aimed to develop a semi - automatic, self - learning pattern recognition system capable of detecting defects on the printed circuits boards such as component vacancy, component misalignment, component orientation, component error, and component weld. The research was conducted in three directions: image acquisition, image filtering/recognition and software development. Image acquisition studied the process of forming and digitizing images and some fundamental aspects regarding the human visual perception. The importance of choosing the right camera and illumination system for a certain type of problem has been highlighted. Probably the most important step towards image recognition is image filtering, The filters are used to correct and enhance images in order to prepare them for recognition. Convolution, histogram equalisation, filters based on Boolean mathematics, noise reduction, edge detection, geometrical filters, cross-correlation filters and image compression are some examples of the filters that have been studied and successfully implemented in the software application. The software application developed during the research is customized in order to meet the requirements of the industrial partner. The application is able to analyze pictures, perform the filtering, build libraries, process images and generate log files. It incorporates most of the filters studied and together with the illumination system and the camera it provides a fully integrated framework able to analyze defects on printed circuit boards.
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Quantitative method of viral pollution determination for large volume of water using ferric hydroxide gel impregnated on the surface of glassfibre cartridge filter. The use of ferric hydroxide gel, impregnated on the surface of glassfibre cartridge filter enable us to recover 62.5% of virus (Poliomylitis type I, Lsc strain) exsogeneously added to 400 liters of tap-water. The virus concentrator system consists of four cartridge filters, in which the three first one are clarifiers, where the contaminants are removed physically, without significant virus loss at this stage. The last cartridge filter is impregnated with ferric hydroxide gel, where the virus is adsorbed. After the required volume of water has been processed, the last filter is removed from the system and the viruses are recovered from the gel, using 1 liter of glycine/NaOH buffer, at pH 11. Immediately the eluate is clarified through series of cellulose acetate membranes mounted in a 142mm Millipore filter. For the second step of virus concentration, HC1 1N is added slowly to the eluate to achieve pH 3.5-4. MgC1, is added to give a final concentration of 0.05M and the viruses are readsorbed on a 0.45 , porosity (HA) cellulose acetate membrane, mounted in a 90 mm Millipore filter. The viruses are recovered using the same eluent plus 10% of fetal calf serum, to a final volume of 3 ml. In this way, it was possible to concentrate virus from 400 liters of tap-water, into 1 liter in the first stage of virus concentration and just to 3 ml of final volume in a second step. The efficiency, simplicity and low operational cost, provded by the method, make it feasible to study viral pollution of recreational and tap-water sources.
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L’objectiu d’aquest projecte es basa en l’obtenció de filtres passa banda mitjançant acobladors ressonants en l’ordre dels GHz, amb un ampla de banda fraccional del 30%. En un primer disseny es presentarà l’estudi del coeficient d’acoblament entre partícules ressonants i tot seguit s’introduirà una capacitat interdigital per a augmentar l’acoblament. Mitjançant el nou disseny es demostrarà que es pot arribar a resultats òptims tant en simulacions com a l’hora de fabricar el dispositiu.
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Los requisitos de los dispositivos empleados en los nuevos sistemas de telecomunicaciones son: unas avanzadas prestaciones, reducido tamaño y bajo coste. Actualmente, se utilizan filtros basados en la tecnología SAW para trabajar a frecuencias de microondas. Dado los inconvenientes que presentan dicho tipo de filtros, se pretende substituirlos por filtros basados en tecnología BAW. La topología en escalera es hasta el momento la más extendida para diseñar estos filtros.
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Este proyecto plantea el diseño de un diplexor basado en resonadores BAW, pensado para aplicaciones de comunicaciones móviles. Éste permite a los terminales seleccionar los canales de uplink y downlink en sistemas que utilicen duplexado por división en frecuencia. Se plantean tres alternativas de diseño a partir de filtros implementados con resonadores BAW en una topología en escalera. Éstas serán evaluadas y comparadas considerando las pérdidas de inserción, el rechazo fuera de banda y las dimensiones de la estructura obtenida.