Catalyst-Free Photoredox Addition-Cyclisations: Exploitation of Natural Synergy between Aryl Acetic Acids and Maleimide

Suitably functionalised carboxylic acids undergo a previously unknown photoredox reaction when irradiated with UVA in the presence of maleimide. Maleimide was found to synergistically act as a radical generating photoxidant and as a radical acceptor, negating the need for an extrinsic photoredox catalyst. Modest to excellent yields of the product chromenopyrroledione, thiochromenopyrroledione and pyrroloquinolinedione derivatives were obtained in thirteen preparative photolyses. In situ NMR spectroscopy was used to study each reaction. Reactant decay and product build-up were monitored, enabling reaction profiles to be plotted. A plausible mechanism, whereby photo-excited maleimide acts as an oxidant to generate a radical ion pair, has been postulated and is supported by UV/Vis. spectroscopy and DFT computations. The radical-cation reactive intermediates were also characterised in solution by EPR spectroscopy.

Weathering tests of photocatalytic facade paints containing ZnO and TiO2.

The photocatalytic properties of self-cleaning acrylic paint containing TiO2 and ZnO were studied using Acid Orange 7 as a model compound. Paints were exposed to simulated weathering tests in a QUV panel. The initial photoactivity of the unweathered paints with ZnO was significantly higher. In the case of paints containing P25 the photocatalytic activity increases with weathering time, due to increasing destruction of the polymer resin and consequent exposure of the photocatalyst pigment to the Acid Orange 7 test solution. In contrast, in the case of paints containing ZnO, a decrease in photocatalytic activity is observed after weathering, due to the loss and/or photocorrosion of ZnO particles during the weathering process.

Photocatalytic activity indicator inks for the probing a wide range of surfaces

Three photocatalyst inks based on the redox dyes, Resazurin (Rz), Basic Blue 66 (BB66) and Acid Violet 7 (AV7), are used to assess the photocatalytic activities of a variety of different materials, such as commercial paint, tiles and glass and laboratory made samples of sol–gel coated glass and paint, which collectively exhibit a wide range of activities that cannot currently be probed by any one of the existing ISO tests. Unlike the ISO tests, the ink tests are fast (typically <10 min), simple to employ and inexpensive. Previous work indicates that the Rz ink test at least correlates linearly with other photocatalytic tests such as the photomineralisation of stearic acid. The average time to bleach 90% of the key RGB colour component of the ink, red for Rz and BB66 inks and green for AV7 ink, is determined, ttb(90), for eight samples of each of the different materials tested. Five laboratories conducted the tests and the results revealed an average repeatability and reproducibility of: ca. 11% and ca 21%, respectively, which compare well with those reported for the current ISO tests. Additional work on commercial self-cleaning glass using an Rz ink showed that the change in the red component of the RGB image of the ink correlated linearly with that of the change of absorbance at 608 nm, as measured using UV/vis spectroscopy, and the change in the a* component of the Lab colour analysis of the ink, as measured using diffuse reflectance spectroscopy. As a consequence, all three methods generate the same ttb(90). The advantages of the RGB digital image analysis method are discussed briefly.

Indoor and Outdoor monitoring of photocatalytic activity using a mobile phone app. and a photocatalytic activity indicator ink (paii)

A resazurin (Rz) based photocatalyst activity indicator ink (paii) is used to test the activity of commercial self-cleaning materials. The semiconductor photocatalyst driven colour change of the ink is monitored indoors and outside using a simple mobile phone application that measures the RGB colour components of the digital image of the paii-covered, irradiated sample in real time. The results correlate directly with those generated using a traditional, lab-bound method of analysis (UV–vis spectrophotometry).

Antibacterial titania-based photocatalytic extruded plastic films

Photocatalytic antibacterial low density polyethylene (LDPE)–TiO2 films are produced by an extrusion method and tested for photocatalytic oxidation activity, via the degradation of methylene blue (MB) and photocatalytic antibacterial activity, via the destruction of Escherichia coli. The MB test showed that extruded LDPE films with a TiO2 loading 30 wt.% were of optimum activity with no obvious decrease in film strength, although the activity was less than that exhibited by the commercial self-cleaning glass, Activ®. UVC pre-treatment (9.4 mW cm−2) of the latter film improved its activity, with the level of surface sites available for MB adsorption increasing linearly with UVC dose. Although the MB test revealed an optimum exposure time of ca. 60 min photocatalytic oxidation activity, only 30 min was used in the photocatalytic antibacterial tests in order to combine minimal reduction in film integrity with maximum film photocatalytic activity. The photocatalytic antibacterial activity of the latter film was over 10 times that of a non-UVC treated 30 wt.% TiO2 film, which, in turn was over 100 times more active than Activ®.

The nitric oxide ISO photocatalytic reactor system: Measurement of NOx removal activity and capacity

Although the NO removal-based air-purification ISO method ISO 22197-1:2007 is well established, its preconditioning requirements mean that only the initial activity of the photocatalyst under test is measured owing to the often-reported, gradual alteration of the surface kinetics for NO oxidation by air through the accumulation of surface HNO3. Herein, we compare the photocatalytic NO removal abilities of a number of different, common TiO2 materials, surface-saturated with photogenerated HNO3, with their behaviours observed during the typical 5 h-long ISO standard test. It is found that all the TiO2 materials studied eventually become largely NO to NO2 converters after sufficient exposure to NO under irradiation (>5 h) due to the accumulation of surface HNO3. The UV exposure time, t*, necessary to reach this HNO3 saturated condition is different for each different catalyst. As a consequence, an alternative preconditioning process for the ISO method is proposed which can be used to provide a more realistic measure of the photocatalytic activity of the underlying material and provide a measure of the NOx removing capacity of the photocatalytic material under test.

Powder semiconductor photocatalysis in aqueous solution: An overview of kinetics-based reaction mechanisms

A brief, historical overview of 10 apparently different, although in some cases, upon inspection, closely related, popular proposed reaction mechanisms and their associated rate equations, is given and in which the rate expression for each mechanism is derived from basic principles, Appendix A. In Appendix B, each of the 5 main mechanisms are tested using datasets, comprising initial reaction rate vs. organic pollutant concentration, [P] and incident irradiance, ρ, data, reported previously for TiO2, where P is phenol, 4-chlorophenol and formic acid. The best of those tested, in terms of overall fit, simplicity, usefulness and versatility is the disrupted adsorption kinetic model proposed by Ollis. The usual basic assumptions made in constructing these mechanisms are reported and the main underlying concerns explored.

Produção científica em revistas internacionais pelos autores da acta médica portuguesa

As revistas científicas locais e regionais têm sido amplamente criticadas por alguns autores. Além disso, dificilmente são indexadas nas bases de dados internacionais, o que reduz a visibilidade dos seus artigos. Objectivo: Analisar a produção científica internacional dos autores que publicaram na Acta Médica Portuguesa no ano de 2008. Métodos: Construi-se uma base de dados com todos os autores que publicaram durante o ano de 2008 na Acta Médica Portuguesa. Em Julho de 2009 recolheu-se do Science Citation Index a produção de todos estes autores publicada nos cinco anos anteriores (2003-2007). Analisaram-se as revistas em que publicaram, o Factor de Impacto destas revistas, as referencias destes artigos, e as citações recebidas. Resultados: Os 78 artigos publicados pela Acta Médica Portuguesa em 2008 foram escritos por 259 autores diferentes. Destes autores, 94 (36,3%) escreveram 420 artigos entre 2003-2007, indexados no Science Citation Index. Estes artigos apareceram em 249 revistas diferentes, com um Factor de Impacto médio de 2,973 (DP = 2,92). A revista com maior Factor de Impacto foi The Lancet (FI2008 = 28,409) com dois artigos publicados. Destes autores, 87 tinham recebido alguma citação aos seus artigos, com um total de 5001 citações. Das 14035 referências destes 420 artigos, apenas 10 eram a algum trabalho publicado na Acta Médica Portuguesa. Conclusão: Os autores que publicam na Acta Médica Portuguesa têm uma boa quantidade de publicações internacionais, em revistas com um considerável Factor de Impacto e recebem um razoável número de citações. Pelo contrário, estes autores quando publicam em revistas internacionais citam extremamente pouco os artigos da Acta Médica Portuguesa.

Layout och typografi i vetenskapliga artiklar : En kartläggning av konventioner gällande grafisk formgivning inom matematik, medicin och utbildningsvetenskap

En deskriptiv visuell innehållsanalys genomfördes med en korpus bestående av vetenskapliga artiklar från 30 topprankade tidskrifter jämnt fördelade på de tre disciplinerna matematik, medicin och utbildningsvetenskap, med syfte att undersöka om det fanns ett samband mellan tidskrifternas disciplintillhörighet och den grafiska formgivningen. Kartläggningen omfattade layout (bl.a. sidformat, spalter, marginalstorlek, användning av grafiska element, placering av tabeller, figurer och pagina) och typografiskt utseende hos titel, rubriker, brödtext och abstrakt (t.ex. teckenstorlek, textjustering, teckengrovlek, typsnitt, färg och radavstånd). Resultaten visar att disciplinerna använde olika men även gemensamma konventioner i sitt grafiska utseende. Matematik uppvisade enkelspaltig layout med liten typografisk variation, genomgående användning av typsnitt från familjen Transitional eller Transitional/Didone för hela dokumentet, avsaknad av kulört färg och sällan användning av grafiska element. Medicin uppvisade större variation med användning av kulört färg, icke-centrerad typografi med både sansseriff- och seriff-typsnitt, grafiska element och ramar som förstärker det ofta använda dubbelspaltiga gridsystemet. Utbildningsvetenskap uppvisade en grafisk design som återfanns i båda disciplinerna, men påminde mest om matematik till utseendet. Kodbok ingår i sin helhet som bilaga. Uppsatsen i sig är delvis formgiven med utgångspunkt i de erhållna resultaten.

Factor XIII Val34Leu is a genetic factor involved in the aetiology of venous thrombosis

A mutation in the factor XIII gene (FXIII Val34Leu) gene was recently reported to confer protection against myocardial infarction, but its relationship with venous thrombosis is unknown. In addition, a mutation in the 5'-untranslated region of the FXII gene (46 C→T) was identified which is associated with low plasma levels of the protein. Its prevalence in patients with venous thrombosis is also unknown. We investigated the frequency of the FXIII Val34Leu and FXII 46 C→T mutations in 189 patients with deep venous thrombosis and in 187 age-, gender- and race-matched controls. FXIII Val34Leu was detected in 38.6% of the patients and in 41.2% of the controls. Interestingly, homozygosity for the FXIII mutation was found in 1.6% of the patients and in 9.6% of the controls. yielding an odds ratio (OR) for venous thrombosis of 0.16 (95% CI: 0.05-0.5). The OR for heterozygotes was 1.1 (95% CI: 0.7-1.7). The FXII 46 C→T mutation was detected in 46.0% of the patients and in 48.6% of the controls. The OR for heterozygotes was 0.9 (95% CI: 0.6-1.4) and for homozygotes the OR was 0.8 (95% CI: 0.3-1.9). Our data indicate that the FXII 46 C→T mutation is unlikely to be a major risk factor for venous thrombotic disease. In contrast, the homozygous state for FXIII Val34Leu is a strong protective factor against venous thrombosis, which emerges as a novel generic factor involved in the aetiology of thrombophilia.

Mapeamento das revistas científicas de medicina disponíveis no Portal de Periódicos da Capes que publicam revisões sistemáticas

Pós-graduação em Bases Gerais da Cirurgia - FMB

Indicadores de impacto, visibilidade e colaboração para a produção científica da Pós-graduação brasileira: um estudo nos programas de excelência na área de Zootecnia

Pós-graduação em Ciência da Informação - FFC

Produção científica dos Programas de Pós-Graduação de excelência no Brasil: colaboração internacional e impacto na área de Zootecnia

This research aimed to study the international scientific collaboration, through co-authorship, and the impact of full papers published in journals Qualis A1 and A2 of Graduate Programs in Animal Science of excellence (2007-2009). Through the indicators of production of graduate evaluation from CAPES, the research gathered the scientific production of three graduate programs, adding up to 125 articles. The citations received were gathered from the SCOPUS database and the impact of journals from the SCImago Journal & Country Rank. In order to investigate the correlation among the indicators analyzed, Pearson’s linear correlation coefficients were calculated. It was observed that the Impact Factor (IF) of the journal may influence the number of citations and that there is a weak trend for association of IFs with the number of coauthor countries. It was not observed a statistically significant correlation between the number of collaborating countries and citations received by the article.