44 research outputs found

    Design and optical characterisation of an efficient light trapping structure for dye-sensitized solar cell integrated windows

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    Windows integrated with semi-transparent photovoltaics (PVs) such as Dye-Sensitized Solar Cells (DSSCs) show good potential in improving building performance, in term of providing daylight, reducing unnecessary solar heat gain and also generating electricity onsite. However, low cell efficiency remains an obstacle for their applications in windows. Using light trapping structures in DSSCs shows potentially to improve solar to electrical conversion efficiency. In this work, different pyramid-patterned titanium dioxide (TiO2) geometries are designed to enhance the photon absorption in DSSCs, and characterised using a Monte-Carlo algorithm based 3D ray-tracing simulation. Various studies were carried out under average irradiation, spectrum dependent irradiation and different solar incidental angles, respectively. The simulation results at the average irradiation wavelength (540 nm) were compared to those from a previous study using Scanning Photocurrent Microscopy (SPCM) and a reasonable agreement has been achieved. It was found that the structure based on the pyramid array of side wall angle 54.7° can significantly enhance light absorption by up to ~25% and the maximum achievable photocurrent density (MAPD) by up to ~45% across the spectrum of 380-800 nm, when compared to a planar control counterpart

    Scanning photocurrent microscopy of 3D printed light trapping structures in dye-sensitized solar cells

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    Converting solar energy directly into electricity as a clean and renewable energy resource is immensely important to solving the energy crisis and environmental pollution problems induced by the consumption of fossil fuels. Dye-sensitized solar cells (DSSCs) provide a technically and economically credible alternative that could challenge the dominance of conventional p-n junction photovoltaic devices in the solar energy market. DSSCs use dye molecules adsorbed at the surface of nanocrystalline oxide semiconductors such as TiO2 to collect sunlight. These thin films require a large surface area, to adsorb many dye molecules, and mesoporous channels so the electrolyte can permeate the film and regenerate the dye molecules. This favourable morphology is traditionally achieved by the random assembly of a network of nanoparticles by the sintering process. Two-photon polymerization is a 3D printing technique used to fabricate structures with feature resolutions down to 100 nm. We use this technique to fabricate TiO¬2 thin films of optimised 3D micro-design for use in DSSCs. Our films have a considerable advantage over the conventional (random assembly) films as it allows the implementation of light scattering designs which are shown to significantly enhance photocurrent in the cell by up to ~25%

    A systematic review of platinum and taxane resistance from bench to clinic: an inverse relationship

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    We undertook a systematic review of the pre-clinical and clinical literature for studies investigating the relationship between platinum and taxane resistance. Medline was searched for (1) cell models of acquired drug resistance reporting platinum and taxane sensitivities and (2) clinical trials of platinum or taxane salvage therapy in ovarian cancer. One hundred and thirty-seven models of acquired drug resistance were identified. 68.1% of cisplatin-resistant cells were sensitive to paclitaxel and 66.7% of paclitaxel-resistant cells were sensitive to cisplatin. A similar inverse pattern was observed for cisplatin vs. docetaxel, carboplatin vs. paclitaxel and carboplatin vs. docetaxel. These associations were independent of cancer type, agents used to develop resistance and reported mechanisms of resistance. Sixty-five eligible clinical trials of paclitaxel-based salvage after platinum therapy were identified. Studies of single agent paclitaxel in platinum-resistant ovarian cancer where patients had previously recieved paclitaxel had a pooled response rate of 35.3%, n=232, compared to 22% in paclitaxel naïve patients n=1918 (p<0.01, Chi-squared). Suggesting that pre-treatment with paclitaxel may improve the response of salvage paclitaxel therapy. The response rate to paclitaxel/platinum combination regimens in platinum-sensitive ovarian cancer was 79.5%, n=88 compared to 49.4%, n=85 for paclitaxel combined with other agents (p<0.001, Chi-squared), suggesting a positive interaction between taxanes and platinum. Therefore, the inverse relationship between platinum and taxanes resistance seen in cell models is mirrored in the clinical response to these agents in ovarian cancer. An understanding of the cellular and molecular mechanisms responsible would be valuable in predicting response to salvage chemotherapy and may identify new therapeutic targets

    Quantum transport of 2D electron system in GaAs/AlGaAs double-quantum wells.

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    Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

    Expression and Androgen Regulation of C-Cam Cell Adhesion Molecule Isoforms in Rat Dorsal and Ventral Prostate

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    C-CAM is an epithelial cell adhesion molecule with two major splice variants that differ in the length of the cytoplasmic domain. C-CAM1 (long (L)-form) strongly suppresses the tumorigenicity of human prostate carcinoma cells. In contrast, C-CAM2 (short (S)-form) does not exhibit tumor-suppressive activity. In the present study we have investigated the functional significance of L-form and S- form C-CAM in rat prostate by examining their expression and distribution in different prostate lobes and their response to androgen deprivation. RNase protection assays with a probe for both C-CAM isoforms detected high levels of C-CAM messages in the rat dorso-lateral prostate (DLP). L- and S- form proteins, localized by indirect immunofluorescence using isoform-specific antipeptide antibodies, were co- expressed on the apical surface of prostate epithelial cells in normal DLP. Androgen depletion did not significantly change the steady state levels of C-CAM message and protein expression in the DLP, although there was a change in the pattern of protein expression in these lobes. In contrast, C -CAM isoform messages and proteins were undetectable in normal ventral prostate (VP) but increased markedly in this lobe in response to castration, producing isoform ratios similar to those in DLP. These results demonstrate that coordinate expression of C- CAM isoforms is maintained in the VP following androgen depletion and suggest that androgen suppresses C-CAM expression in VP but not in DLP. These results suggest that balanced expression of L- and S-form C- CAM is important for normal prostate growth and differentiation

    Database of useful data for SWAT modelling and report on data availability and quality for hydrological modelling and water quality modeling in the Black Sea Catchments

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    This document reports on data availability and quality for hydrological modeling and water quality modeling in the Black Sea Catchments. The report gives an overview of different hydrological models such as Soil Water Assessment Tool (SWAT) that is our selected tool for hydrological modeling and water quality modeling in the Black Sea Catchments, followed by Delft3D a 2D/3D modeling program, SOBEK, MONERIS, and Qualitative Reasoning (QR) models. The main hydrological projects developed in the regions are also described in order to benefit from existing modeling data suitable also for SWAT model. In the partners' contribution chapter, each partner gives an overview of meteorological, hydrological and other SWAT data it can contribute or may be collected from the official owners. It is concluded that Ukraine, Romania and Hungary territory is well covered with SWAT needed data from enviroGRIDS partners, other data for the rest of the area as upstream of Danube Catchments are mostly available through ICPDR or at Global, European and regional database repositories

    Memristive effects due to charge transfer in graphene gated through ferroelectric CuInP2S6

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    Ferroelectricity at the nanometre scale can drive the miniaturisation and wide application of ferroelectric devices for memory and sensing applications. The two-dimensional van der Waals (2D-vdWs) ferroelectrics CuInP2S6 (CIPS) has attracted much attention due to its robust ferroelectricity found in thin layers at room temperature. Also, unlike many 2D ferroelectrics, CIPS is a wide band gap semiconductor, well suited for use as a gate in field-effect transistors (FETs). Here, we report on a hybrid FET in which the graphene conducting channel is gated through a CIPS layer. We reveal hysteresis effects in the transfer characteristics of the FET, which are sensitive to the gate voltage, temperature and light illumination. We demonstrate charge transfer at the CIPS/graphene interface in the dark and under light illumination. In particular, light induces a photodoping effect in graphene that varies from n- to p-type with increasing temperature. These hybrid FETs open up opportunities for electrically and optically controlled memristive devices

    Combined effect of sodium selenite and docetaxel on PC3 metastatic prostate cancer cell line

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    Docetaxel and sodium selenite are well known for their anticancer properties. While resistance to docetaxel remains an obstacle in prostate cancer chemotherapy, sodium selenite, has been exploited as a new therapeutic approach. Currently, development of therapies affecting a multitude of cell targets, have been proposed as a strategy to overcome drug resistance. This association may reduce systemic toxicity counteracting a wide range of side effects. Here we report the effect of docetaxel and sodium selenite combination on the PC3 prostate cancer cell line, derived from bone metastasis. Therefore we evaluate cell growth, cell cycle progression, viability, mitochondria membrane potential, cytochrome C, Bax/Bcl2 ratio, caspase-3 expression and reactive oxygen species production. Our results suggest that sodium selenite and docetaxel combination have a synergistic effect on cell growth inhibition (67%) compared with docetaxel (22%) and sodium selenite (24%) alone. This combination also significantly induced cell death, mainly by late apoptosis vs necrosis, which is correlated with mitochondria membrane potential depletion. On the other hand, cytochrome C, Bax/Bcl2 ratio and caspase-3, known as proapoptotic factors, significantly increased in the presence of sodium selenite alone, but not in the presence of docetaxel in monotherapy or in combination with sodium selenite. These findings suggest that docetaxel and sodium selenite combination may be more effective on prostate cancer treatment than docetaxel alone warranting further evaluation of this combination in prostate cancer therapeutic approach
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