Polimorfismos genéticos no gene XRCC3 e dano no DNA em trabalhadores expostos ocupacionalmente a formaldeído

A exposição a formaldeído (FA), classificado como cancerígeno pela International Agency for Cancer Research (IARC), está epidemiologicamente associada a cancro e a alterações nucleares detectáveis pelo ensaio dos micronúcleos por bloqueio da citocinese (CBMN). Este método permite determinar vários marcadores de genotoxicidade, nomeadamente micronúcleos – biomarcadores de quebra ou perda de cromossomas; pontes nucleoplásmicas – biomarcador de re-arranjo cromossómico, pouca reparação e fusão de telómeros e, protusões nucleares – biomarcador de DNA amplificado. O gene X-ray repair cross-complementing group 3 (XRCC3) está envolvido na reparação de ligações cruzadas na recombinação de homólogos e quebras na cadeia dupla de DNA. Foi reportado pelo menos um polimorfismo no gene, o Thr241Met que tem sido associado a um aumento do dnao no DNA em vários estudos.

DNA interaction and cytotoxicity studies of new ruthenium(II) cyclopentadienyl derivative complexescontaining heteroaromatic ligands

Four ruthenium(II) complexes with the formula [Ru(eta(5)-C(5)H(5))(PP)L][CF(3)SO(3)], being (PP = two triphenylphosphine molecules), L = 1-benzylimidazole, 1; (PP = two triphenylphosphine molecules), L = 2,2'bipyridine, 2; (PP = two triphenylphosphine molecules), L = 4-Methylpyridine, 3; (PP = 1,2-bis(diphenylphosphine) ethane), L = 4-Methylpyridine, 4, were prepared, in view to evaluate their potentialities as antitumor agents. The compounds were completely characterized by NMR spectroscopy and their crystal and molecular structures were determined by X-ray diffraction. Electrochemical studies were carried out giving for all the compounds quasi-reversible processes. The images obtained by atomic force microscopy (AFM) suggest interaction with pBR322 plasmid DNA. Measurements of the viscosity of solutions of free DNA and DNA incubated with different concentrations of the compounds confirmed this interaction. The cytotoxicity of compounds 1234 was much higher than that of cisplatin against human leukemia cancer cells (HL-60 cells). IC(50) values for all the compounds are in the range of submicromolar amounts. Apoptotic death percentage was also studied resulting similar than that of cisplatin. (C) 2010 Elsevier Inc. All rights reserved.

Microstrip antenna array for multiband dedicated short range communications systems

Dedicated Short Range Communications (DSRC) is the key enabling technology for the present and future vehicular communication for various applications, such as safety improvement and traffic jam mitigation. This paper describes the development of a microstrip antenna array for the roadside equipment of a DSRC system, whose characteristics are according with the vehicular communications standards. The proposed antenna, with circular polarization, has a wide bandwidth, enough to cover the current European DSRC 5.8 GHz band and the future 5.9 GHz band for next generation DSRC communications. (C) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53: 2794-2796, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26394

Comparação de métodos de extração de DNA e deteção de organismos geneticamente modificados em alimentos processados derivados de milho

Diante dos avanços biotecnológicos o cultivo de plantas geneticamente modificadas, como, por exemplo, o milho (Zea mays), aumentou consideravelmente nos últimos anos. Embora esta tecnologia apresente comprovados benefícios em relação ao aumento da produtividade e durabilidade do alimento, a população ainda receia em consumir produtos geneticamente modificados. O objetivo deste trabalho foi comparar dois protocolos baseados na utilização de CTAB e avaliar qual o melhor para extração de DNA em alimentos processados derivados de milho, bem como identificar dois dos resíduos transgênicos mais comuns em gêneros alimentícios derivados de milho: Cry1ab e Cry1F. Para isto, 14 amostras derivadas de milho foram avaliadas utilizando dois diferentes protocolos de extração de DNA e a deteção dos eventos transgênicos conduzida pela técnica de PCR qualitativa. Entre as amostras analisadas, 57% resultaram positivas para deteção de ambos os eventos de milho transgênico avaliados.

Vertical CNT-Si Photodiode Array

Agências financiadoras: National Natural Science Foundation of China - 61204077; Shenzhen Science and Technology Innovation Commission - JCYJ20120614150521967

Non-uniform microstrip antenna array for RX DSRC communications

The urgent need to mitigate traffic problems such as accidents, road hazards, pollution and traffic jam have strongly driven the development of vehicular communications. DSRC (Dedicated Short Range Communications) is the technology of choice in vehicular communications, enabling real time information exchange among vehicles V2V (Vehicle-to-Vehicle) and between vehicles and infrastructure V2I (Vehicle-Infrastructure). This paper presents a receiving antenna for a single lane DSRC control unit. The antenna is a non-uniform array with five microstrip patches. The obtained beam width, bandwidth and circular polarization quality, among other characteristics, are compatible with the DSRC standards, making this antenna suitable for this application. © 2014 IEEE.

The impact of different power dividers used in a non-uniform planar antenna array

Wireless communications are widely used for various applications, requiring antennas with different features. Often, to achieve the desired radiation pattern, is necessary to employ antenna arrays, using non-uniform excitation on its elements. Power dividers can be used and the best known are the T-junction and the Wilkinson power divider, whose main advantage is the isolation between output ports. In this paper the impact of this isolation on the overall performance of a circularly polarized planar antenna array using non-uniform excitation is investigated. Results show a huge decrease of the array bandwidths either in terms of return loss or in polarization, without resistors. © 2014 IEEE.

Insights into the mechanims underlyng the antiproliferative potential of a Co(II) coordination compound bearing 1,10-Phenanthroline-5,6-Dione: DNA and protein interaction studies

The very high antiproliferative activity of [Co(Cl)(H2O)(phendione)(2)][BF4] (phendione is 1,10-phenanthroline-5,6-dione) against three human tumor cell lines (half-maximal inhibitory concentration below 1 mu M) and its slight selectivity for the colorectal tumor cell line compared with healthy human fibroblasts led us to explore the mechanisms of action underlying this promising antitumor potential. As previously shown by our group, this complex induces cell cycle arrest in S phase and subsequent cell death by apoptosis and it also reduces the expression of proteins typically upregulated in tumors. In the present work, we demonstrate that [Co(Cl)(phendione)(2)(H2O)][BF4] (1) does not reduce the viability of nontumorigenic breast epithelial cells by more than 85 % at 1 mu M, (2) promotes the upregulation of proapoptotic Bax and cell-cycle-related p21, and (3) induces release of lactate dehydrogenase, which is partially reversed by ursodeoxycholic acid. DNA interaction studies were performed to uncover the genotoxicity of the complex and demonstrate that even though it displays K (b) (+/- A standard error of the mean) of (3.48 +/- A 0.03) x 10(5) M-1 and is able to produce double-strand breaks in a concentration-dependent manner, it does not exert any clastogenic effect ex vivo, ruling out DNA as a major cellular target for the complex. Steady-state and time-resolved fluorescence spectroscopy studies are indicative of a strong and specific interaction of the complex with human serum albumin, involving one binding site, at a distance of approximately 1.5 nm for the Trp214 indole side chain with log K (b) similar to 4.7, thus suggesting that this complex can be efficiently transported by albumin in the blood plasma.

Micronutrients intake associated with DNA damage assessed by in a human biomonitoring study

Nutrition science has evolved into a multidisciplinary field that applies molecular biology and integrates individual health with the epidemiologic investigation of population health. Nutritional genomics studies the functional interaction of food and its components, macro and micronutrients, with the genome at the molecular, cellular, and systemic level. Diet can influence cancer development in several ways, namely direct action of carcinogens in food that can damage DNA, diet components (macro or micronutrients) that can block or induce enzymes involved in activation or deactivation of carcinogenic substances. Moreover, inadequate intake of some molecules involved in DNA synthesis, repair or methylation can influence mutation rate or changes in gene expression. Several studies support the idea that diet can influence the risk of cancer; however information concerning the precise dietary factor that determines human cancer is an ongoing debate. A lot of epidemiological studies, involving food frequency questionnaires, have been developed providing important information concerning diet and cancer, however, diet is a complex composite of various nutrients (macro and micronutrients) and non-nutritive food constituents that makes the search for specific factors almost limitless.

Cobalt complexes bearing scorpionate ligands: Synthesis, characterization, cytotoxicity and DNA cleavage

A number of novel, water-stable redox-active cobalt complexes of the C-functionalized tripodal ligands tris(pyrazolyl)methane XC(pz)(3) (X = HOCH2, CH2OCH2Py or CH2OSO2Me) are reported along with their effects on DNA. The compounds were isolated as air-stable solids and fully characterized by IR and FIR spectroscopies, ESI-MS(+/-), cyclic voltammetry, controlled potential electrolysis, elemental analysis and, in a number of cases, also by single-crystal X-ray diffraction. They showed moderate cytotoxicity in vitro towards HCT116 colorectal carcinoma and HepG2 hepatocellular carcinoma human cancer cell lines. This viability loss is correlated with an increase of tumour cell lines apoptosis. Reactivity studies with biomolecules, such as reducing agents, H2O2, plasmid DNA and UV-visible titrations were also performed to provide tentative insights into the mode of action of the complexes. Incubation of Co(II) complexes with pDNA induced double strand breaks, without requiring the presence of any activator. This pDNA cleavage appears to be mediated by O-centred radical species.

Detect and pointing algorithm's performance for a planar smart antenna array: a review

An adaptive antenna array combines the signal of each element, using some constraints to produce the radiation pattern of the antenna, while maximizing the performance of the system. Direction of arrival (DOA) algorithms are applied to determine the directions of impinging signals, whereas beamforming techniques are employed to determine the appropriate weights for the array elements, to create the desired pattern. In this paper, a detailed analysis of both categories of algorithms is made, when a planar antenna array is used. Several simulation results show that it is possible to point an antenna array in a desired direction based on the DOA estimation and on the beamforming algorithms. A comparison of the performance in terms of runtime and accuracy of the used algorithms is made. These characteristics are dependent on the SNR of the incoming signal.

Printed nonuniform antenna array for WI-FI sectorized communications

Wireless networks have joined to the sports venues, offering to the public a set of facilities, such as the access to email, news, and also to use the social networking, uploading their photos. New challenges have emerged to provide Wi-Fi in this densely populated stadiums, such as increasing capacity and coverage. In this article, an access point antenna array to cover a sector of a stadium is presented. Its structure, designed in a low cost material allows to reduce the total manufacturing costs, an important factor due to the large number of antennas required in these venues. The material characteristic, the broad bandwidth of operation (300 MHz), along with to the low side lobe levels, important to reduce interference between sectors, makes this antenna well-positioned for wireless communications in these particular locals. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2037-2041, 2015.

Non-uniform printed antenna array for wireless communications in sports arenas

Wireless communications had a great development in the last years and nowadays they are present everywhere, public and private, being increasingly used for different applications. Their application in the business of sports events as a means to improve the experience of the fans at the games is becoming essential, such as sharing messages and multimedia material on social networks. In the stadiums, given the high density of people, the wireless networks require very large data capacity. Hence radio coverage employing many small sized sectors is unavoidable. In this paper, an antenna is designed to operate in the Wi-Fi 5GHz frequency band, with a directive radiation pattern suitable to this kind of applications. Furthermore, despite the large bandwidth and low losses, this antenna has been developed using low cost, off-the-shelf materials without sacrificing quality or performance, essential to mass production. © 2015 EurAAP.

System-on-chip field-programmable gate array design for onboard real-time hyperspectral unmixing

Hyperspectral instruments have been incorporated in satellite missions, providing large amounts of data of high spectral resolution of the Earth surface. This data can be used in remote sensing applications that often require a real-time or near-real-time response. To avoid delays between hyperspectral image acquisition and its interpretation, the last usually done on a ground station, onboard systems have emerged to process data, reducing the volume of information to transfer from the satellite to the ground station. For this purpose, compact reconfigurable hardware modules, such as field-programmable gate arrays (FPGAs), are widely used. This paper proposes an FPGA-based architecture for hyperspectral unmixing. This method based on the vertex component analysis (VCA) and it works without a dimensionality reduction preprocessing step. The architecture has been designed for a low-cost Xilinx Zynq board with a Zynq-7020 system-on-chip FPGA-based on the Artix-7 FPGA programmable logic and tested using real hyperspectral data. Experimental results indicate that the proposed implementation can achieve real-time processing, while maintaining the methods accuracy, which indicate the potential of the proposed platform to implement high-performance, low-cost embedded systems, opening perspectives for onboard hyperspectral image processing.

Coluna de som utilizando array de transdutores de ultrasons

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e Telecomunicações