Facet-Dependent Catalytic Activity of Platinum Nanocrystals for Triiodide Reduction in Dye-Sensitized Solar Cells

Platinum (Pt) nanocrystals have demonstrated to be an effective catalyst in many heterogeneous catalytic processes. However, pioneer facets with highest activity have been reported differently for various reaction systems. Although Pt has been the most important counter electrode material for dye-sensitized solar cells (DSCs), suitable atomic arrangement on the exposed crystal facet of Pt for triiodide reduction is still inexplicable. Using density functional theory, we have investigated the catalytic reaction processes of triiodide reduction over {100}, {111} and {411} facets, indicating that the activity follows the order of Pt(111) > Pt(411) > Pt(100). Further, Pt nanocrystals mainly bounded by {100}, {111} and {411} facets were synthesized and used as counter electrode materials for DSCs. The highest photovoltaic conversion efficiency of Pt(111) in DSCs confirms the predictions of the theoretical study. These findings have deepened the understanding of the mechanism of triiodide reduction at Pt surfaces and further screened the best facet for DSCs successfully.

The Impact of Colleague Peer Review on the Radiotherapy Treatment Planning Process in the Radical Treatment of Lung Cancer

AIMS: Modern radiotherapy uses techniques to reliably identify tumour and reduce target volume margins. However, this can potentially lead to an increased risk of geographic miss. One source of error is the accuracy of target volume delineation (TVD). Colleague peer review (CPR) of all curative-intent lung cancer plans has been mandatory in our institution since May 2013. At least two clinical oncologists review plans, checking treatment paradigm, TVD, prescription dose tumour and critical organ tolerances. We report the impact of CPR in our institution.

MATERIALS AND METHODS: Radiotherapy treatment plans of all patients receiving radical radiotherapy were presented at weekly CPR meetings after their target volumes were reviewed and signed off by the treating consultant. All cases and any resultant change to TVD (including organs at risk) or treatment intent were recorded in our prospective CPR database. The impact of CPR over a 13 month period from May 2013 to June 2014 is reported.

RESULTS: One hundred and twenty-two patients (63% non-small cell lung carcinoma, 17% small cell lung carcinoma and 20% 'clinical diagnosis') were analysed. On average, 3.2 cases were discussed per meeting (range 1-8). CPR resulted in a change in treatment paradigm in 3% (one patient proceeded to induction chemotherapy, two patients had high-dose palliative radiotherapy). Twenty-one (17%) had a change in TVD and one (1%) patient had a change in dose prescription. In total, 6% of patients had plan adjustment after review of dose volume histogram.

CONCLUSION: The introduction of CPR in our centre has resulted in a change in a component of the treatment plan for 27% of patients receiving curative-intent lung radiotherapy. We recommend CPR as a mandatory quality assurance step in the planning process of all radical lung plans.

The death of massive stars - II. Observational constraints on the progenitors of Type Ibc supernovae

The progenitors of many Type II core-collapse supernovae (SNe) have now been identified directly on pre-discovery imaging. Here, we present an extensive search for the progenitors of Type Ibc SNe in all available pre-discovery imaging since 1998. There are 12 Type Ibc SNe with no detections of progenitors in either deep ground-based or Hubble Space Telescope archival imaging. The deepest absolute BVR magnitude limits are between -4 and - 5 mag. We compare these limits with the observed Wolf-Rayet population in the Large Magellanic Cloud and estimate a 16 per cent probability that we have failed to detect such a progenitor by chance. Alternatively, the progenitors evolve significantly before core-collapse or we have underestimated the extinction towards the progenitors. Reviewing the relative rates and ejecta mass estimates from light-curve modelling of Ibc SNe, we find both incompatible with Wolf-Rayet stars with initial masses >25 M⊙ being the only progenitors. We present binary evolution models that fit these observational constraints. Stars in binaries with initial masses ≲ 20 M⊙ lose their hydrogen envelopes in binary interactions to become low-mass helium stars. They retain a low-mass hydrogen envelope until ≈104 yr before core-collapse; hence, it is not surprising that Galactic analogues have been difficult to identify.

Supernovae and radio transients in M82

We present optical and near-infrared (NIR) photometry and NIR spectroscopy of SN 2004am, the only optically detected supernova (SN) in M82. These demonstrate that SN 2004am was a highly reddened Type II-P SN similar to the low-luminosity Type II-P events such as SNe 1997D and 2005cs. We show that SN 2004am was located coincident with the obscured super star cluster M82-L, and from the cluster age infer a progenitor mass of 12{^{+ 7}_{- 3}} M⊙. In addition to this, we present a high spatial resolution Gemini-North Telescope K-band adaptive optics image of the site of SN 2008iz and a second transient of uncertain nature, both detected so far only at radio wavelengths. Using image subtraction techniques together with archival data from the Hubble Space Telescope, we are able to recover a NIR transient source coincident with both objects. We find the likely extinction towards SN 2008iz to be not more than AV ˜ 10. The nature of the second transient remains elusive and we regard an extremely bright microquasar in M82 as the most plausible scenario.

2P/Encke, the Taurid complex NEOs and the Maribo and Sutter's Mill meteorites

Aims. 2P/Encke is a short period comet that was discovered in 1786 and has been extensively observed and studied for more than 200years. The Taurid meteoroid stream has long been linked with 2P/Encke owing to a good match of their orbital elements, even thoughthe comet’s activity is not strong enough to explain the number of observed meteors. Various small near-Earth objects (NEOs) havebeen discovered with orbits that can be linked to 2P/Encke and the Taurid meteoroid stream. Maribo and Sutter’s Mill are CM typecarbonaceous chondrite that fell in Denmark on January 17, 2009 and April 22, 2012, respectively. Their pre-atmospheric orbits placethem in the middle of the Taurid meteoroid stream, which raises the intriguing possibility that comet 2P/Encke could be the parentbody of CM chondrites.
Methods. To investigate whether a relationship between comet 2P/Encke, the Taurid complex associated NEOs, and CM chondritesexists, we performed photometric and spectroscopic studies of these objects in the visible wavelength range. We observed 2P/Enckeand 10 NEOs on August 2, 2011 with the FORS instrument at the 8.2 m Very Large Telescope on Cerro Paranal (Chile).
Results. Images in the R filter, used to investigate the possible presence of cometary activity around the nucleus of 2P/Encke andthe NEOs, show that no resolved coma is present. None of the FORS spectra show the 700 nm absorption feature due to hydratedminerals that is seen in the CM chondrite meteorites. All objects show featureless spectra with moderate reddening slopes at λ < 800nm. Apart for 2003 QC10 and 1999 VT25, which show a flatter spectrum, the spectral slope of the observed NEOs is compatible withthat of 2P/Encke. However, most of the NEOs show evidence of a silicate absorption in lower S/N data at λ > 800 nm, which is notseen in 2P/Encke, which suggests that they are not related.
Conclusions. Despite similar orbits, we find no spectroscopic evidence for a link between 2P/Encke, the Taurid complex NEOs andthe Maribo and Sutter’s Mill meteorites. However, we cannot rule out a connection to the meteorites either, as the spectral differencesmay be caused by secondary alteration of the surfaces of the NEOs. 

Improving the wellbeing of staff who work in palliative care settings: a systematic review of psychosocial interventions

Background: Staff in palliative care settings perform emotionally demanding roles which may lead to psychological distress including stress and burnout. Therefore, interventions have been designed to address these occupational risks.

Aim: To investigate quantitative studies exploring the effectiveness of psychosocial interventions that attempt to improve psychological wellbeing of palliative care staff.

Design: A systematic review was conducted according to methodological guidance from UK Centre for Reviews and Dissemination.

Data sources: A search strategy was developed based on the initial scans of palliative care studies. Potentially eligible research articles were identified by searching the following databases: CINAHL, MEDLINE (Ovid), PsycINFO and Web of Science. Two reviewers independently screened studies against pre-set eligibility criteria. To assess quality, both researchers separately assessed the remaining studies using the Quality Assessment Tool for Quantitative Studies.

Results: A total of 1786 potentially eligible articles were identified – nine remained following screening and quality assessment. Study types included two randomised controlled trials, two non-randomised controlled trial designs, four one-group pre–post evaluations and one process evaluation. Studies took place in the United States and Canada (5), Europe (3) and Hong Kong (1). Interventions comprised a mixture of relaxation, education, support and cognitive training and targeted stress, fatigue, burnout, depression and satisfaction. The randomised controlled trial evaluations did not improve psychological wellbeing of palliative care staff. Only two of the quasi-experimental studies appeared to show improved staff wellbeing although these studies were methodologically weak.

Conclusion: There is an urgent need to address the lack of intervention development work and high-quality research in this area.

Percepções de duas professoras do 1º ciclo sobre actividades preconizadas no EEC

Este estudo insere-se no quadro de uma investigação mais ampla, onde se pretende averiguar que mudanças evidenciam os professores do 1º Ciclo do Ensino Básico (1º CEB) nas concepções de ensino e de aprendizagem, após a implementação do Programa de Formação de Professores do 1º CEB em Ensino Experimental das Ciências (PFEEC). Discute-se, com base nos resultados de uma entrevista semi-estruturada, a situação particular de duas formandas em dois momentos distintos do processo: antes do PFEEC e após a conclusão deste programa de formação. Pretende-se dar resposta às seguintes questões de investigação: (i) Que expectativas revelam os professores do 1º Ciclo sobre as actividades que irão ser implementadas no PFFEC? (ii) Que potencialidades atribuem os professores às actividades, no âmbito das Ciências Experimentais, após a realização desse programa de formação? (iii) Que dificuldades encontram esses professores na implementação dessas actividades?

Inovação tecnológica nas PME e dinâmica regional em Portugal

Tese de dout., Economia (Economia da Informação), Faculdade de Economia, Univ. do Algarve, 2004

Um escritor algarvio do século XVIII em Ayamonte: Damião António de Lemos Faria e Castro

Damião António de Lemos Faria e Castro foi o mais importante escritor algarvio do século XVIII. Viveu entre 1715 e 1789, em Portimão e em Faro, e foi autor de duas obras de grande dimensão: Aula da nobreza lusitana, em sete tomos (entre 1749 e 1761), e História Geral de Portugal e suas Conquistas, em vinte tomos (o primeiro dos quais aparecido em 1786 e os últimos, já póstumos, em 1806). Em ambas recorre amiúde a autores espanhóis, demonstrando a integração e a unidade fundamental da cultura ibérica. Além disso, escrevia correntemente em língua castelhana. Mas Damião esteve também vinculado muito especialmente a Ayamonte. Com efeito, durante cerca de dois anos – 1749/1750 – esteve refugiado em Ayamonte, porque perseguido pela justiça portuguesa. E nesta cidade andaluza da foz do Guadiana compôs alguns opúsculos que mandou imprimir em Sevilha. Outros escritos seus de Ayamonte ficaram manuscritos, como seja a Relación Geográfico-Historica de algunos terrenos de la Frontera de Portugal, y España, desde Ayamonte hasta Badajoz.