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As nanopartículas de semicondutores são de grande interesse científico e tecnológico devido ao fato das suas propriedades eletrônicas e ópticas dependerem do tamanho das partículas. Os nanocristais de semicondutores têm sido intensamente investigados, por exemplo, como nanocargas em diversas matrizes poliméricas. Neste trabalho é apresentada a síntese de nanocompósitos obtidos pela incorporação de nanocristais (NCs) de ZnO no copolímero poli-{trans-[RuCl 2 (vpy) 4 ]/sty} (sty = estireno e vpy = 4-vinilpiridina). Numa primeira etapa, o copolímero foi preparado por meio da reação entre os monômeros trans- [RuCl 2 (vpy) 4 ] e estireno. Em seguida, NCs de ZnO passivados organicamente foram misturados com o copolímero poli-{trans-[RuCl 2 (vpy) 4 ]/sty}, em CH 2 Cl 2 , para produzir filmes poliméricos do nanocompósito após evaporação do solvente (método ex situ). As propriedades destes materiais foram comparadas com as de nanocompósitos análogos obtidos a partir da polimerização in situ na presença de NCs de ZnO.Nanosized semiconductor particles are of great scientific and technological interest because of their size-dependent electronic and optical properties. Semiconductor nanocrystals have been investigated, for example, as nano-fillers for diverse polymer matrices in order to produce new optically active materials. Here we report, for the first time, results concerning the preparation of nanocomposites made of ZnO nanocrystals (NCs) incorporated in the co-polymer poly-{trans-[RuCl 2 (vpy) 4 ]/sty (sty = styrene and vpy = 4-vinylpyridine). In a first step, the co-polymer was prepared by reaction of trans-[RuCl 2 (vpy) 4 ] with styrene. Then, organically capped ZnO NCs and poly-{trans-[RuCl 2 (vpy) 4 ]/sty} were mixed in CH 2 Cl 2 to produce cast films of the nanocomposites after evaporation of the solvent (ex situ method). The properties of these materials were compared to those of nanocomposites obtained by in situ polymerization in the presence of ZnO NCs. Keywords: ruthenium(II) complexes, nanocomposites, ZnO nanocrystals IntroductionSemiconductor nanocrystals (NCs) show size-dependent optical properties and have been investigated as new optical materials in the field of nanotechnology.1 For example, these nanosized particles have been used together with polymers to produce new optically active inorganic/ polymer nanocomposites. This approach takes advantage not only of the intrinsic properties of the starting materials but might also result in new properties due to synergistic effects arising from the combination of the inorganic and organic components.2 Depending on the nanoparticles' characteristics and the synthesis/processing of the polymer matrices, there are several synthetic strategies to prepare polymer nanocomposites. Available approaches include solgel methods, 3 melt-processing 4,5 and in situ polymerization.6,7The homogeneous distribution of inorganic nanoparticles within the polymer matrix and the strong interface adhesion between the matrix and nano-fillers are important aspects to be conside...

The quantification of target analytes in complex matrices requires special calibration approaches to compensate for additional capacity or activity in the matrix samples. The standard addition is one of the most important calibration procedures for quantification of analytes in such matrices. However, this technique requires a great number of reagents and material, and it consumes a considerable amount of time throughout the analysis. In this work, a new calibration procedure to analyze biological samples is proposed. The proposed calibration, called the addition calibration technique, was used for the determination of zinc (Zn) in blood serum and erythrocyte samples. The results obtained were compared with those obtained using conventional calibration techniques (standard addition and standard calibration). The proposed addition calibration was validated by recovery tests using blood samples spiked with Zn. The range of recovery for blood serum and erythrocyte samples were 90-132% and 76-112%, respectively. Statistical studies among results obtained by the addition technique and conventional techniques, using a paired two-tailed Student's t-test and linear regression, demonstrated good agreement among them.

Prevalência de fatores de risco de doença arterial coronária em funcionários de hospital universitário e sua correlação com estresse psicológicoPrevalence of risk factors of coronary artery disease in university hospital employees and the correlation with psychological stress (HU) da UFSC. 5. Nutricionista do HU/UFSC. 6. Bioquímica do HU/UFSC. 7. Mestre em Informática e profissional voluntário. Doença arterial coronária Estresse psicológico Fatores de risco abstractObjective: The present work aimed to evaluate the different risk factors (RF) of coronary artery disease (CAD) in a university hospital volunteer employees, regarding the correlation with psychological stress. Methods: Fifty-two volunteers participated in the study (41 females and 11 males), which included anthropometric measurement, clinical examination, and measurement of the arterial blood pressure. Arterial blood was collected from them to quantify the levels of total cholesterol, HDL-cholesterol (HDL), triglycerides (TG), and LDL-cholesterol (LDL). The body mass index (BMI), and waist-to-hip ratio (WHR) were determined. The participants have also answered a questionnaire regarding stress. The different RF were quantified and evaluated. Results: From the participants, 73.1% were considered stressed, 32.7% were hypertenses, and 36.5% had TC > 200mg dl -1 . Females were significantly more stressed than man (p < .05), and proportionally males had more HDL < 40mg dl -1 than females (p < .05). The stressed people also presented TC above 200mg dl -1 (p < .05). The coronary artery disease risk was low for 53.8% of the people, medium for 23.1%, moderate for 21.2%, and high for 2.6%. The waist-to-hip risk was high in 15% of the stressed patients, in 35,5% of hypertenses, and in 10.5% in the ones with TC > 200mg/dl. The body mass risk was considered low for most of the stressed, hypertenses, and the ones with TC > 200mg dl -1 . Conclusion: This study shows the importance of the psychological stress in the evaluation of different RF for CAD and this knowledge is very important in the preventive intervention for this disease. Coronary heart disease Psychological stress Coronary heart risk factorsPrimeira submissão em 17/06/03 Última submissão em 15/03/04

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A síntese e a caracterização de um novo filme polimérico composto por poli-{trans-[RuCl 2 (vpy) 4 ]-estireno-4-vinilpiridina} impregnado com nanopartículas de prata são descritas neste trabalho. Este material foi obtido por polimerização em meio não aquoso envolvendo o complexo mononuclear trans- [RuCl 2 (vpy) 4 ], o estireno (sty) e a 4-vinilpiridina (4-vpy), usando peróxido de benzoila como iniciador. As dimensões nanométricas das partículas de prata foram confirmadas através de microscopia eletrônica de transmissão (TEM) e por espectroscopia eletrônica no UV-visível. A morfologia do terpolímero foi caracterizada por microscopia eletrônica de varredura (MEV). As propriedades térmicas foram analisadas por termogravimetria (TGA) e calorimetria diferencial de varredura (DSC). A ação antimicrobiana do polímero impregnado com nanopartículas de prata foi avaliada utilizando microrganismos Gram positivo e Gram negativo, Staphylococcus aureus (ATCC 25923) e Escherichia coli (ATCC 25922), respectivamente. A atividade antimicrobiana do terpolímero com nanopartículas de prata foi confirmada pela presença de um halo de inibição do crescimento bacteriano nos meios de cultura semeados.The synthesis and characterization of a new polymeric material composed of poly-{trans-[RuCl 2 (vpy) 4 ]-styrene-4-vinylpyridine} impregnated with silver nanoparticles are here described. This material was obtained by a non aqueous polymerization reaction involving trans-[RuCl 2 (vpy) 4 ], styrene (sty) and 4-vinylpyridine (4-vpy), using benzoyl peroxide as initiator. The silver particles nanometric dimensions were confirmed by transmission electron microscopy (TEM) and UV-visible spectroscopy. The terpolymer morphology was characterized by scanning electron microscopy (SEM). Thermal properties were analyzed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The antimicrobial action of the polymer impregnated with silver nanoparticles was evaluated by the use of Gram positive and Gram negative microorganisms, Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922), respectively. The antimicrobial activity of the terpolymer with silver nanoparticles was confirmed by the presence of a bacterial growth inhibition halo in seeded culture media.Keywords: ruthenium complex, polymer, silver nanoparticles, antimicrobial IntroductionFunctional polymer networks have gained great importance in many fields of scientific research as well as in industrial applications. These applications will increase greatly due to the variety of possible modifications in the chemical and physical properties of these materials. 1 Network polymers based on styrene, prepared by well-developed suspension polymerization processes, retain many advantageous qualities for a microcomposite host matrix. These include ease of preparation, controlled surface area and porous structure, good thermal resistance and reasonable chemical inertness. 2 Polymers based on the application of coordination forces have been prepared recently. The f...