Achados da tomografia computadorizada de alta resolu����o na histiocitose de células de Langerhans pulmonar

OBJETIVO: Caracterizar, por meio da tomografia computadorizada de alta resolu����o, as principais altera����es pulmonares da histiocitose de células de Langerhans. MATERIAIS E M��TODOS: Foram avaliadas, retrospectivamente, as tomografias computadorizadas de alta resolu����o de oito pacientes com diagn��stico comprovado da doen��a a partir de bi��psia pulmonar a c��u aberto, bi��psia transbr��nquica, estudos de imuno-histoqu��mica e/ou les��es extrapulmonares associadas. RESULTADOS: Pequenas les��es c��sticas, arredondadas e de paredes finas foram observadas em todos os pacientes. N��dulos, com distribui����o predominantemente perif��rica no par��nquima pulmonar, estavam presentes em 75% dos exames estudados. As les��es apresentaram distribui����o difusa, com predom��nio nos ter��os superior e m��dio dos pulm��es em todos os casos, mas acometimento dos recessos costofr��nicos foi observado em 25% dos pacientes. CONCLUS��O: A compara����o das tomografias computadorizadas de alta resolu����o com radiografias de t��rax mostrou que cistos de paredes finas e pequenos n��dulos n��o podem ser avaliados satisfatoriamente por radiografias convencionais. A tomografia computadorizada de alta resolu����o, por sua capacidade de detectar e caracterizar cistos e n��dulos pulmonares, permite o diagn��stico de histiocitose de células de Langerhans pulmonar com alta probabilidade.

Tomografia computadorizada das células etmoidais intra e extramurais: ensaio iconogr��fico

O desenvolvimento dos seios paranasais �� um processo intricado que se inicia na vida intrauterina e termina na idade adulta. Dos seios da face, as células etmoidais s��o provavelmente as estruturas mais complexas e as que est��o associadas com o maior n��mero de variantes da normalidade. Varia����es no padr��o de pneumatiza����o das células etmoidais podem ser divididas em intra ou extramurais. Intramurais s��o aquelas que ao se desenvolverem mant��m contato com o labirinto etmoidal, e extramurais as que se desenvolvem isoladamente. A tomografia computadorizada �� a ferramenta mais ��til na avalia����o de processos inflamat��rios dos seios paranasais. De igual modo, ela �� importante para o planejamento pr��-operat��rio e controle p��s-operat��rio, pois possibilita grande detalhe anat��mico das estruturas normais e detec����o precisa de suas variantes. Neste ensaio iconogr��fico os autores descrevem as principais variantes da normalidade do labirinto etmoidal e suas rela����es com estruturas adjacentes. Cirurgias endosc��picas para o tratamento de afec����es dos seios paranasais t��m-se tornado cada vez menos invasivas, o que certamente aumentar�� a demanda por relat��rios de imagem cada vez mais ricos em detalhes desta regi��o.

Tumor de células granulares acometendo a ��rbita em uma crian��a

Os autores relatam um raro caso de tumor de células granulares no m��sculo reto medial de um menino de sete anos de idade. S��o descritos os achados cl��nicos, histol��gicos e radiol��gicos do caso, bem como uma breve revis��o da literatura.

A tomografia por emiss��o de p��sitrons com 2-[18F]-fluoro-2-desoxi-D-glicose �� custo-efetiva em pacientes com c��ncer de pulm��o n��o pequenas células no Brasil

OBJETIVO: Comparar a acur��cia e a custo-efetividade do estadiamento metab��lico (EM) com o FDG-PET em rela����o ao estadiamento convencional (EC) no estadiamento inicial de pacientes com c��ncer de pulm��o n��o pequenas células (CPNPC). MATERIAIS E M��TODOS: Noventa e cinco pacientes com diagn��stico inicial de CPNPC foram estadiados antes do in��cio do tratamento. Os resultados do EC e EM foram comparados quanto a defini����o do tratamento e incid��ncia de toracotomia f��til em cada estrat��gia. RESULTADOS: O EM com FDG-PET classificou 48,4% dos pacientes como est��dio mais avan��ado e 5,3% como menos avan��ado. O resultado do EM modificaria o tratamento em 41% dos pacientes. A toracotomia foi considerada f��til em 47% dos pacientes com EC e em 19% dos casos com EM. O custo das toracotomias f��teis em oito pacientes no EM foi de R$ 79.720, enquanto em 31 pacientes no EC seria de R$ 308.915. Apenas esta economia seria mais que suficiente para cobrir os custos de todos os exames de FDG-PET nos 95 pacientes (R$ 126.350) ou de FDG-PET/CT (R$ 193.515). CONCLUS��O: O EM com FDG-PET tem maior acur��cia que o EC em pacientes com CPNPC. A FDG-PET e FDG-PET/CT s��o custo-efetivas e sua utiliza����o se justifica economicamente na sa��de p��blica no Brasil.

Histiocitose de células de Langerhans diagnosticada em um paciente de idade avan��ada

A histiocitose de células de Langerhans �� uma doen��a rara caracterizada prolifera����o de células de Langerhans. Neste artigo descrevemos um caso de histiocitose de células de Langerhans em um paciente de 63 anos, com uma les��o expansiva periorbital como primeiro sintoma e cuja tomografia computadorizada revelou acometimento pulmonar caracter��stico da doen��a. A condu����o do caso, os achados radiol��gicos e os resultados s��o apresentados.

Desenvolvimento e aplica����o de células eletroqu��micas em camada delgada

Theoretical and practical aspects concerning construction and use of a thin layer electrochemical cell are presented. Construction was realized by a simple technic and geometry was optimized in order to minimize the problems of electrical resistance. A well known redox system was studied ((Fe(III)(CN)6(3-)/Fe(II)(CN) 6(4-)) using two experimental methods, cyclic voltammetry and pulse chronopotentiometry. A numerical integration based-program was developed to calculate the voltammetric current in case of nernstian and non-nernstian behaviours and a diffusional model was used to treat the chronopotentiometric data. Thermodynamic (potential, concentration) and kinetic parameters (diffusion coefficient) were successfully determined for the redox system studied in this work.

Tecnologia de células a combust��vel

The fuel cell principle was discovered by Sir Grove 150 years ago. However material problems prohibited its commercialization for a long time. A change has been occurring during the last 30 years, so two types of fuel cell technologies can be distinguished: low and high temperature operation cells. Nowadays, only phosphoric acid cells are commercially offered as 200 kWel power plants. Membrane cells are more suitable for automobile electrotraction with a very low (or no) environmental impact. The fuel continues, however, to play a very particular role, since hydrogen is not easy to store and to transport. The more promising target is the utilization of liquid methanol. The Brazilian scenario concerning this kind of technology is discussed.

Células a combust��vel de baixa pot��ncia para aplica����es estacion��rias

A paradigmatic shift in developing fuel cell for stationary applications has been occurring in the last ten years. Previously, 100 kW class to a few MW class power plants were preferred but recently, the development has drifted towards units of only a few kW. The motivation is the present market situation, which favors disperse residential electric power generation from natural or liquefied gas. Membrane-type fuel cells are very promising for this application, due to their present state of development in the automobile industry. More recently, small ceramic fuel cells (SOFC) has also been found to be adequate for this application. Considering a family of 4 members, 1 kW (electric) units seem to be optimal for individual residences. This presentation discusses briefly the Brazilian scenario with respect to these units.

M��todos de prepara����o de nanopart��culas met��licas suportadas em carbono de alta ��rea superficial, como eletrocatalisadores em células a combust��vel com membrana trocadora de pr��tons

Fuel cells are attracting much interest as efficient and clean energy conversion devices. The main components of low temperature fuel cells are the electrocatalysts used to promote the anodic and cathodic reactions, which are based on platinum and platinum alloys. These electrocatalysts are normally prepared in the form of metal nanoparticles supported on a conductive material, usually high surface area carbon, to improve catalyst utilization and reduce cost. This work presents and comments some methods used presently to produce these electrocatalysts. The performances of the produced electrocatalysts are compared to that of state-of-the-art commercial E-TEK electrocatalysts.

Direcionamentos da tecnologia industrial de células a combust��vel de ��xidos s��lidos

This manuscript shows an overview of the solid oxide fuel cell (SOFC) technology based on industrial developments. The information presented has been collected mostly at conferences that the authors attended. It is observed that several companies have been pursuing the development of the SOFC technology. Significant advances in stability and power density have raised the economic interest in this technology recently. It is revealed that the SOFC materials are essentially the same ones that have been used in the past decades, and that the two most important designs of pre-commercial SOFC prototypes are the tubular and planar ones.

Em busca da sustentabilidade: células solares sensibilizadas por extratos naturais

The present work reports the use of anthocyanins extracted from mulberry (Morus Alba L.), raspberry (Rubus Idaeus L.) and blueberry (Vaccinium myrtillus L.) as sensitizers in dye-sensitized solar cells. The conversion efficiency of these devices is dependent on the extracts employed and can be rationalized in terms of their composition and spectral properties. Solar cells sensitized by the mulberry extract showed the highest efficiency among the fruits investigated. Moreover, a 16 cm�� active area solar cell with the mulberry extract has presented fair good efficiency of conversion for natural dye-based solar cells, besides stability over twenty weeks, showing perspectives for developing these low cost devices with a commercial viability.

Desenvolvimento de processo de produ����o de conjuntos eletrodo-membrana-eletrodo para células a combust��vel baseadas no uso de membrana polim��rica condutora de pr��tons (PEMFC) por impress��o a tela

Proton exchange membrane fuel cell (PEMFC) requires membrane electrode assemblies (MEA) to generate electrical energy from hydrogen and oxygen. In this study a MEA production process by sieve printing and an ink composition were developed to produce catalyst layers of MEAs. The deposition of the exact catalyst content was possible on cathodes and anodes with only one print step. The optimal ink developed shown viscosity of 2.75 Pa s, density 1.27 g cm-3, total solid content of 33.76 % and tack of 92 U.T. The electrodes prepared in only one printing step showed higher performance than those prepared in several steps.

Desenvolvimento de tecnologia para confec����o de eletrodos e conjuntos eletrodo-membrana-eletrodo (MEA) por impress��o �� tela para aplica����o em m��dulos de pot��ncia de células PEMFC

Significant functions in the Proton Exchange Membrane Fuel Cells (PEMFCs) rely on Gas Diffusion Layers (GDLs), such as control the water balance in the membrane electrode assembly (MEA), allow suitable gas permeability and porosity, etc. Aware of the GDL importance in the cell performance and its great demand in scale-up projects, the fuel cell research group at Instituto de Pesquisas Energ��ticas e Nucleares (IPEN) has developed a Sieve Printing method (innovative in Brazil) as a strategic solution for producing GDL and electrodes used in high power PEMFC stacks. The method has shown to be adequate to fabricate low cost electrodes, GDLs of different dimensions and to produce any amount of MEAs for power stacks.

Atividade de extratos de Arrabidaea chica (Humb. & Bonpl.) Verlot obtidos por processos biotecnol��gicos sobre a prolifera����o de fibroblastos e células tumorais humanas

Arrabidaea chica (H&B) Verlot is a plant popularly known as Pariri and this species is a known source of anthocyanins, flavonoids and tannins. This report describes an approach involving enzymatic treatment prior to extraction procedures to enhance A chica crude extract anticancer activity. Anticancer activity in human cancer cell lines in vitro using a 48 h SRB cell viability assay was performed to determine growth inhibition and cytotoxic properties. The final extraction yield without enzyme treatment was higher (24.28%) compared to the enzyme-treated material (19.03%), with an enhanced aglycones anthocyanin ratio as determined by HPLC- DAD and LC-MS with direct infusion.

C��LULAS SOLARES SENSIBILIZADAS POR CORANTES NATURAIS: UM EXPERIMENTO INTRODUT��RIO SOBRE ENERGIA RENOV��VEL PARA ALUNOS DE GRADUA����O

An interesting practical experiment about the preparation of dye–sensitized solar cells (DSSC) using natural dyes were carried out by the undergraduate students in the chemistry course at UNICAMP . Natural dyes were extracted from blueberries (Vaccinium myrtillus L.), jabuticabas (Myrciaria cauliflora), raw and cooked beets (Beta vulgaris L.), and annattos (Bixa orellana L.), which were used to sensitize TiO2 films that composed the photoanode in the DSSC. A polymer electrolyte containing an iodide/triiodide redox couple was used in lieu of the use of liquid solutions to prevent any leakage in the devices. A maximum solar-to-electric energy conversion of 0.26 �� 0.02% was obtained for the solar cell prepared with annatto extracts. This experiment was an effective way to illustrate to the undergraduate students how to apply some of the chemical concepts that they learned during their chemistry course to produce electric energy from a clean and renewable energy source. Teachers could also exploit the basics of the electronic transitions in inorganic and organic compounds (e.g., metal-to-ligand charge transfer and ϖ-ϖ* transitions), thermodynamics (e.g., Gibbs free energy), acid–base reactions in the oxide solid surface and electrolyte, and band theory (i.e., the importance of the Fermi level energy).