6,302 research outputs found
Temperature-induced lipocalin is required for basal and acquired thermotolerance in Arabidopsis. Plant Cell Environ.
No full textCharacterization of optically switchable holographic polymer-dispersed liquid crystal transmission gratings
No full text[[abstract]]This study characterizes the all-optical switching effect in holographic polymer-dispersed liquid crystal transmission gratings. The light-induced switching behaviors of these structures are due to the doped azobenzene-derived LC (azo-LC), which changes the refractive index of phase-separated LC within the polymer composite. This study also optimizes the polymer-dispersed liquid crystal formulation containing 15 wt.% azo-LC and 35 wt.% nematic LC to achieve a grating performance with a tunable diffraction efficiency of 78% and a fast switching-on time (0.5 s) with a relatively small light stimulus of 9 mW/cm(2). (C) 2011 Elsevier B.V. All rights reserved.[[note]]SC
Molecular modification on dye-sensitized solar cells by phosphonate self-assembled monolayers
No full text[[abstract]]Molecular modification by phosphonic acids forms phosphonate dipole layers on TiO2 and influences photoelectrochemical characteristics of DSSCs. V-oc is dipole-related and eta is dominated by V-oc. A phosphonic acid with a negative dipole moment shifts the TiO2 E-CB closer to the vacuum level and causes a larger V-oc. A higher E-CB increases the E-F gradient and results in a larger J(sc). APPA has the largest negative dipole moment, so the APPA-modified DSSC shows the largest V-oc and J(sc), and the highest eta. The dark currents of modified DSSCs are not just dipole-related. They are dominated mainly by the electron tunneling effect. A shorter phosphonate dipole layer offers a smaller tunneling barrier and makes reverse electron injection easier. So the CEPA- and APPA-modified DSSCs show smaller charge transfer impedances at the TiO2/dye/electrolyte interfaces and larger dark currents than the other four modified DSSCs. Although the TFBPA dipole layer is not the longest, the TFBPA-modified DSSC exhibits the largest impedance and smallest dark current because the charge recombinations at the interface and reverse injection of electrons are suppressed by the strong electron-withdrawing property.[[note]]SC
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
Full text linkIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Chi-square tests applied to the frequencies of dl and wt offspring from twelve backcrosses between <i>dl</i>/<i>dl</i> and <i>dl/wt</i> parents, with an expected 1∶1 ratio.
No full text<p>Chi-square tests applied to the frequencies of dl and wt offspring from twelve backcrosses between <i>dl</i>/<i>dl</i> and <i>dl/wt</i> parents, with an expected 1∶1 ratio.</p
Comparative Study Of The Influence Of Natural Convection On Directional Solidification Of Al-3.5 Wt% Ni And Al-7 Wt% Si Alloys
Full text linkWe present numerical simulations of thermosolutal convection for directional solidification of Al-3.5 wt% Ni and Al-7 wt% Si. Numerical results predict that fragmentation of dendrite arms resulting from dissolution could be favored in Al-7 wt% Si, but not in Al-3.5 wt% Ni. Corresponding experiments are in qualitative agreement with the numerical predictions. Distinguishing the two fragmentation mechanisms, namely dissolution and remelting, is critical during experiments on earth, when fluid flow is dominant. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved
Hysteresis phenomenon and wetting characteristics of molten Sn-3.0 wt.%Ag-0.5 wt.%Cu on different tilting substrates
No full textThe hysteresis phenomenon and wetting characteristics of molten Sn-3.0 wt.%Ag-0.5 wt.%Cu on wetting and non-wetting tilting substrates at different temperatures were investigated. The viewpoint on negative interfacial tension was proposed in this paper to explain the spreading and wetting behaviors for sample on different tilted substrates. The critical sliding angle was defined as limited tilting angle of surface at which the molten drop slid down and the upper and lower contact angles of molten drop were measured as the advancing and receding contact angles, respectively. Wetting experiments were performed to determine how contact angle and contact hysteresis on alumina and oxygen-free copper tilting substrates changed with temperature. Static, limited tilting, advancing and receding contact angles on two kinds of substrates were measured at different temperatures. In general, both negative interfacial tension and hysteresis for sample on copper were much larger than that on alumina over the range of temperatures studied, indicating better wettability but worse motion characteristics for the former. It was due to the larger adhesion between solid and liquid than the cohesion of liquid, the negative interfacial tension and the acute contact angle. (C) 2009 Elsevier B.V. All rights reserved
Multiple granularity access to navigated Hypermedia documents using temporal meta-information
No full text[[abstract]]Various multimedia document systems that capture, integrate, and synchronously present media have been implemented in many areas. As data volume grows and the diversity of new medium increases, how to efficiently locate the segments of interest is an important issue. To address this problem, this paper presents a framework that facilitates multiple levels of access to navigated hypermedia documents in three different granularities: HTML slide level, navigation event level, and sentence level. In contrast to traditional approaches, hierarchical access structure of navigated hypermedia documents can be exploited by analyzing temporal meta-information captured in the recording stage or computed in the speech-text alignment process. The proposed framework has been applied in the developed "Web-based Synchronized Multimedia Lecture System" for efficient content access.[[note]]SC
Toward better retrieval and presentation by exploring cross-media correlations
No full text[[abstract]]This paper addresses explicit correlation and implicit correlation between various media streams in a composite multimedia document, the so-called navigated hypermedia document in our language learning system, in order to facilitate document retrieval and synchronized presentation. For replaying a recorded lecture in a form as close as possible to the original classroom experience, we devised a capturing mechanism to explicitly record all the lecturing media streams and relations between them, including instructors voice, slide change of the HTML lectures, and various guiding actions (e.g., tele-pointers, pen strokes, document scrolling, keyword highlighting, and text annotations) on HTML-based slides. In addition, for more effective learning, we study three different aspects - temporal, spatial, and content relation - of the implicit correlations that are inherently hidden between the media involved. The implicit relations are discovered by three designed processes: the speech-text alignment process for temporally synchronized speech-text presentation, the automatic scrolling process for the viewing windows spatial synchronization, and the content dependency checking process to ensure consistency of the content processed and the relations involved. The experimental results show that exploring cross-media correlations is helpful for system development in document presentation and retrieving. Users are allowed to replay a vivid and learning-effective multimedia lecture and to access the desired part of the document very easily via cross-media indexing. Hence the results have been applied to the development of online multimedia language learning systems aimed at improving students English and Chinese language capabilities.[[note]]SC
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