23,624 research outputs found

    Quantitative chemical analysis of perovskite deposition using spin coating

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    Lead and halide ion compositions of spin coated organo-lead halide perovskite films have been quantified using ion chromatography (IC) and atomic absorption spectroscopy (AAS) using perovskite films manufactured by 5 different researchers (3 replicates per treatment) to monitor variability between researchers and individual researcher reproducibility. Planar and mesoporous TiO2-coated glass substrates have been studied along with tribromide (CH3NH3PbBr3), triiodide (CH3NH3PbI3) and mixed halide (CH3NH3PbI3�xClx) perovskite films. The data show low yields of spin coated perovskite material (ca. 1%) and preferential deposition of I� over Cl� in mixed halide films

    Factors related to discontinued clinic attendance by patients with podoconiosis in southern Ethiopia: a qualitative study

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    Background Podoconiosis is a lymphoedema of non-infectious cause which results in long-term ill health in affected individuals. Simple, effective treatment is available in certain parts of Ethiopia, but evidence indicates that not all patients continue collecting treatment supplies from clinic sites once started. We used qualitative techniques to explore factors related to discontinued attendance at outreach clinics of a non-government organization in southern Ethiopia. Methods A cross-sectional qualitative study was conducted in four clinic sites through unstructured in-depth interviews, key informant interviews and focus group discussions with the involvement of 88 study subjects. Results Discontinuation of clinic visits is common among podoconiosis patients. The reasons were: remoteness from the clinic sites, unrealistic expectation of ‘special’ aid, worry about increasing stigma, illness and misconceptions about treatment. Conclusions Several of these factors are remediable through community and individual information and education. Appropriate routes to deliver this information must be identified. Certain factors (such as distance to clinic sites and stigma) require substantial expansion of services or liaison with village-level government health services

    On outflow boundary conditions for CT-based computation of FFR: Examination using PET images

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    CT-based computations of fractional flow reserve (FFR) have been widely utilized for evaluating functional severity of a coronary artery stenosis. Whilst this approach has been successful clinically, assumptions involved in the analysis still need to be investigated for further improvement in predictive accuracy. To better understand the sensitivity of computational FFRs on outflow boundary condition – typically reflecting patient's own physiology only through anatomical features – FFR computations for 10 patients with different degree of stenosis was conducted. The computations were based on 3D anatomical model reconstructed from CT images and patient-specific in/outflow boundary conditions (BC). Two outflow BCs were considered: (1) conventional morphology-based and (2) PET perfusion-based conditions. The results showed that the FFRs derived from the two boundary conditions agree in general. It was also found that the FFRs computed with the morphology-based BC tend to estimate higher functional severity, especially in patients with reduced vasodilatory response under hyperaemia – an essential physiological condition in FFR measurement. Further investigation was made by varying hyperaemic resistances (30%-90% of the baseline) in the morphology-based BC. The variation of FFR for the varied resistances was narrow for patients with mild stenosis and wider for those who have severe stenosis. This latter approach confirmed that variability of FFR due to outflow condition tends to come from overestimation of vasodilatory response, especially those who have abnormal myocardial perfusion. The results suggest that outflow conditions that are more representative of each patient could be an effective way to improve CT-based FFR computation

    A Comparison of a Brain-Computer Interface and an Eye Tracker: Is There a More Appropriate Technology for Controlling a Virtual Keyboard in an ALS Patient?

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    The ability of people affected by amyotrophic lateral sclerosis (ALS), muscular dystrophy or spinal cord injuries to physically interact with the environment, is usually reduced. In some cases, these patients suffer from a syndrome known as locked-in syndrome (LIS), defined by the patient’s inability to make any move-ment but blinks and eye movements. Tech communication systems available for people in LIS are very limited, being those based on eye-tracking and brain-computer interface (BCI) the most useful for these patients. A comparative study between both technologies in an ALS patient is carried out: an eye tracker and a visual P300-based BCI. The purpose of the study presented in this paper is to show that the choice of the technology could depend on user´s preference. The evaluation of performance, workload and other subjective measures will allow us to determine the usability of the systems. The obtained results suggest that, even if for this patient the BCI technology is more appropriate, the technology should be always tested and adapted for each user.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Constraints on soluble aerosol iron flux to the Southern Ocean at the Last Glacial Maximum.

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    Relief of iron (Fe) limitation in the Southern Ocean during ice ages, with potentially increased carbon storage in the ocean, has been invoked as one driver of glacial-interglacial atmospheric CO2 cycles. Ice and marine sediment records demonstrate that atmospheric dust supply to the oceans increased by up to an order of magnitude during glacial intervals. However, poor constraints on soluble atmospheric Fe fluxes to the oceans limit assessment of the role of Fe in glacial-interglacial change. Here, using novel techniques, we present estimates of water- and seawater-soluble Fe solubility in Last Glacial Maximum (LGM) atmospheric dust from the European Project for Ice Coring in Antarctica (EPICA) Dome C and Berkner Island ice cores. Fe solubility was very variable (1-42%) during the interval, and frequently higher than typically assumed by models. Soluble aerosol Fe fluxes to Dome C at the LGM (0.01-0.84 mg m(-2) per year) suggest that soluble Fe deposition to the Southern Ocean would have been ≥10 × modern deposition, rivalling upwelling supply.This work is a contribution to the European Project for Ice Coring in Antarctica (EPICA), a joint European Science Foundation/European Commission (EC) scientific programme. This study was funded by a NERC studentship to T.M.C. and E.W.W. is funded by a Royal Society professorship.This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/ncomms885

    Afatinib efficacy against squamous cell carcinoma of the head and neck cell lines in vitro and in vivo.

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    Epidermal growth factor receptor (EGFR) inhibitors have demonstrated efficacy in squamous cell carcinoma of the head and neck (SCCHN). In addition to EGFR, other ErbB family members are expressed and activated in SCCHN. Afatinib is an ErbB family blocker that has been approved for treating patients with EGFR-mutated nonsmall cell lung cancer. We sought to determine the efficacy of afatinib in preclinical models and compare this to other EGFR-targeted agents. Afatinib efficacy was characterized in a panel of ten SCCHN cell lines and found to be most effective against cell lines amplified for EGFR. Afatinib had lower IC(50) values than did gefitinib against the same panel. Two EGFR-amplified cell lines that are resistant to gefitinib are sensitive to afatinib. Cetuximab was not found to have a synergistic effect with afatinib either in vitro or in vivo. Both afatinib and cetuximab were effective in tumor xenograft model. Afatinib is an effective agent in SCCHN especially in models with EGFR amplification

    Longest Common Extensions in Sublinear Space

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    The longest common extension problem (LCE problem) is to construct a data structure for an input string TT of length nn that supports LCE(i,j)(i,j) queries. Such a query returns the length of the longest common prefix of the suffixes starting at positions ii and jj in TT. This classic problem has a well-known solution that uses O(n)O(n) space and O(1)O(1) query time. In this paper we show that for any trade-off parameter 1≤τ≤n1 \leq \tau \leq n, the problem can be solved in O(nτ)O(\frac{n}{\tau}) space and O(τ)O(\tau) query time. This significantly improves the previously best known time-space trade-offs, and almost matches the best known time-space product lower bound.Comment: An extended abstract of this paper has been accepted to CPM 201

    Dirac field in topologically massive gravity

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    We consider a Dirac field coupled minimally to the Mielke-Baekler model of gravity and investigate cosmological solutions in three dimensions. We arrive at a family of solutions which exists even in the limit of vanishing cosmological constant.Comment: 12 pages. Title changed. Conclusion extended. Appendix added. To appear in Gen. Rel. Gra
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