In this communication we describe the application of a conductive polymer gas sensor as an air pressure sensor. The device consists of a thin doped poly(4'-hexyloxy-2,5-biphenylene ethylene) (PHBPE) film deposited on an interdigitated metallic electrode. The sensor is cheap, easy to fabricate, lasts for several months, and is suitable for measuring air pressures in the range between 100 and 700 mmHg.

Com base nas grandes modificações das propriedades de materiais poliméricos resultantes da inclusão de unidades organometálicas, descrevem-se neste trabalho a síntese e a caracterização de um polímero organometálico conjugado com estrutura semelhante à de poli(p-fenilenovinileno) (PPV), o qual apresenta grupos 1,1'-ferrocenileno no lugar de 1,4fenileno em sua cadeia principal. Sintetizado por meio de reação de acoplamento de McMurry de 1,1'-ferrocenodialdeído, o poli(1,1'-ferrocenilenovinileno) (PFV) se apresentou na forma de um sólido de cor laranja, amorfo e insolúvel tanto em solventes polares quanto em apolares. Para caracterização do PFV, empregaram-se os métodos de espectroscopia no infravermelho (FTIR), espectroscopia Raman e análise termogravimétrica (TGA).

Motivated by the influence on the physical and chemical properties of polymeric materials caused by the inclusion of organometallic units, the present work is focused on the synthesis and characterization of an organometallic conjugated polymer with similar structure to poly(p-phenylenevinylene) (PPV), in which the phenylene groups are replaced by ferrocenylene units in the main chain. The polymer, poly(1,1'-ferrocenylenevinylene), (PFV), was prepared via McMurry coupling reaction of 1,1'-ferrocenedialdehyde as an orange and amorphous solid, insoluble both in polar and apolar solvents. The characterization of the polymer was carried out employing the following methods: infrared (FTIR) and Raman spectroscopies and thermogravimetric analysis (TGA).

In this work we report efficiency measurements on light-emitting diodes with electrochemically synthesized sulfonated polyaniline as hole transport layer. The anode used in our devices is fluorine-doped tin oxide, the blocking layer is electrochemically synthesized poly(9,9-dioctyl-1,4-fluorenylenevinylene) and the electron transporting material and emitter is tris-(8-hydroxyquinoline) aluminum. Sulfonated polyaniline based devices presented efficiency of 0.79 cd/A.

Vários métodos são empregados na identificação de restos humanos, sendo que a maioria é baseada na comparação entre dados ante-mortem e post-mortem disponíveis. Embora a técnica da impressão digital seja considerada a mais precisa, em muitos casos ela não pode ser utilizada, especialmente quando os corpos foram mutilados, decompostos, queimados ou fragmentados. Nestas situações, os métodos empregados pela Odontologia Legal tornam-se extremamente valiosos, uma vez que os dentes e as restaurações são muito resistentes à destruição pelo fogo, preservando numerosas características individuais. Assim, oferecem a possibilidade de uma identificação acurada e aceita pelas autoridades legais. Este breve artigo de revisão descreve os principais avanços alcançados pela Odontologia Legal, nos últimos 25 anos, quanto ao emprego de radiografias ante- e post-mortem no processo de identificação. Dentre os diversos assuntos tratados, destacam-se: suportes especialmente confeccionados para facilitar o posicionamento e a fixação de filmes radiológicos intra-orais em falecidos com rigor mortis; dispositivos para facilitar a reprodução da geometria de imagens com as de ante-mortem; métodos envolvendo radiografias digitalizadas, as quais podem ser facilmente manipuladas por métodos computacionais, armazenadas e transmitidas por "modem" aos locais de desastre em massa; procedimentos para determinação de idade, identificação de indivíduos desdentados por meio da comparação de radiografias oclusais do maxilar e estudos de validação de radiografias tiradas com intervalos ante- e post-mortem de até 30 anos.

There are various methods for the identification of human remains; most of them are based on comparisons between available ante- and post-mortem data. Although fingerprinting is the most accurate and precise method, in many cases, such as in mutilated, decomposed, burned or fragmented bodies, it cannot be used, and the dental methods become of the utmost importance, since teeth and dental restorations are very resistant to destruction by fire - they keep numerous characteristics, which are quite unique, and offer the possibility of accurate and legally acceptable identification of remains. This brief review describes the progress of forensic dentistry during the last 25 years, regarding the procedures and techniques that use ante-mortem and post-mortem radiographs. Among the discussed progresses one can point out: a specially designed self-supporting film holder that retains intra-oral films in the mouths of deceased persons whose mandibular musculature has been fixed in rigor mortis; positioning devices suitable for reproducing the geometry of ante-mortem radiographic images; methods involving digital radiographs, which can be easily stored in a central archive, retrieved and transmitted, via modem, to mass casualty sites; age estimation procedures; identification of edentulous individuals comparing radiographs of the maxilla; and studies of validation of dental radiographs taken with ante-mortem and post-mortem intervals of up to 30 years.

Poly(p-xylylenes), PPX, are a class of high performance insulating materials with many applications in the electronic component industry. We review herewith the most important synthetic routes to these polymers, described in the literature, since 1904.

This paper presents the design of a simple apparatus that periodically switches off both working and auxiliary electrodes short-circuiting them for a couple of seconds. Depolarization takes place and the initial current is re-established.

We review herewith the use of solids such as activated alumina and other modern Lewis acid catalysts, as well as the influence of different solvents, including water, on the title reactions, described in the last seven years.

The use of GFCI, ground-fault circuit interrupter, in the chemical laboratory is described, to improve the electrical safety of equipments such as rotary evaporators and constant temperature baths.