1,497 research outputs found

    Control of the nanoscale crystallinity and phase separation in polymer solar cells

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    Grazing-incidence x-ray diffraction and atomic force microscopy were performed on bulk heterojunction regioregular poly(3-hexylthiophene) (RR-P3HT) [6,6]-phenyl-C71-butyric acid methyl esters spin-cast films with different film processing conditions to correlate the crystalline nanostructure of P3HT with the corresponding solar cell performance. The increase in long wavelength absorption for solvent annealed films is related to highly conjugated crystal structure of RR-P3HT phase-separated in the active layer. Upon thermal annealing, the solvent annealed 50-nm-thick device shows high solar cell performance with fill factor up to 73% and power conversion efficiency of 3.80%

    Control of the nanoscale crystallinity and phase separation in polymer solar cells

    Get PDF
    Grazing-incidence x-ray diffraction and atomic force microscopy were performed on bulk heterojunction regioregular poly(3-hexylthiophene) (RR-P3HT) [6,6]-phenyl-C71-butyric acid methyl esters spin-cast films with different film processing conditions to correlate the crystalline nanostructure of P3HT with the corresponding solar cell performance. The increase in long wavelength absorption for solvent annealed films is related to highly conjugated crystal structure of RR-P3HT phase-separated in the active layer. Upon thermal annealing, the solvent annealed 50-nm-thick device shows high solar cell performance with fill factor up to 73% and power conversion efficiency of 3.80%

    Dermoscopic characterization and image study of a Sister Mary Joseph nodule in a patient with esophageal cancer

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    AbstractA Sister Mary Joseph nodule (SMJN) is rare cutaneous metastasis spreading to the umbilicus. It originates mostly from an intra-abdominal or pelvic malignancy and is an ominous sign. In this paper, we report a case of a SMJN in a 64-year-old man with esophageal cancer. We recorded his clinical progression, radiologic and nuclear scintigraphic images, and histopathologic and dermoscopic findings. The image study provided information on the localization of the SMJN and dermoscopy showed a polymorphous vascular pattern. The patient received palliative therapy because of terminal disease

    Chaotic Mixing in a Microfluidic Device

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    Summary This paper presents a theoretical investigation into chaotic mixing in low Reynolds number electro-osmotic flows. In this mixing system, the primary flow is the pluglike electro-osmotic flow contributed by the permanent surface charge at the wall, and the secondary electro-osmotic flows (or electro-osmotic recirculating rolls) contributed by the field-effect-induced surface charge act as the perturbed flow. By time-periodic switching two different secondary electro-osmotic flows, it makes streamlines to cross at successive intervals and results in chaotic mixing. Dynamic system techniques such as Poincaré map and finite-time Lyapunov exponent analyses are employed to describe the behaviors of particle motion in this mixing system. Finally, the optimum operating condition (e.g. amplitude and time-switching period) for the mixing is identified

    A Mobile Robot Generating Video Summaries of Seniors' Indoor Activities

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    We develop a system which generates summaries from seniors' indoor-activity videos captured by a social robot to help remote family members know their seniors' daily activities at home. Unlike the traditional video summarization datasets, indoor videos captured from a moving robot poses additional challenges, namely, (i) the video sequences are very long (ii) a significant number of video-frames contain no-subject or with subjects at ill-posed locations and scales (iii) most of the well-posed frames contain highly redundant information. To address this problem, we propose to \hl{exploit} pose estimation \hl{for detecting} people in frames\hl{. This guides the robot} to follow the user and capture effective videos. We use person identification to distinguish a target senior from other people. We \hl{also make use of} action recognition to analyze seniors' major activities at different moments, and develop a video summarization method to select diverse and representative keyframes as summaries.Comment: accepted by MobileHCI'1

    Inhibition of FAK Signaling Elicits Lamin A/C-Associated Nuclear Deformity and Cellular Senescence

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    Focal adhesion kinase (FAK) is a non-receptor kinase that facilitates tumor aggressiveness. The effects of FAK inhibition include arresting proliferation, limiting metastasis, and inhibiting angiogenesis. PF-573228 is an ATP-competitive inhibitor of FAK. Treating lung cancer cells with PF-573228 resulted in FAK inactivation and changes in the expressions of lamin A/C and nuclear deformity. Since lamin A/C downregulation or deficiency was associated with cellular senescence, the senescence-associated β-galactosidase (SA-β-gal) assay was used to investigate whether PF-573228 treatment drove cellular senescence, which showed more SA-β-gal-positive cells in culture. p53 is known to play a pivotal role in mediating the progression of cellular senescence, and the PF-573228-treated lung cancer cells resulted in a higher p53 expression level. Subsequently, the FAK depletion in lung cancer cells was employed to confirm the role of FAK inhibition on cellular senescence. FAK depletion and pharmacological inhibition of lung cancer cells elicited similar patterns of cellular senescence, lamin A/C downregulation, and p53 upregulation, implying that FAK signaling is associated with the expression of p53 and the maintenance of lamin A/C levels to shape regular nuclear morphology and manage anti-senescence. Conversely, FAK inactivation led to p53 upregulation, disorganization of the nuclear matrix, and consequently cellular senescence. Our data suggest a new FAK signaling pathway, in that abolishing FAK signaling can activate the senescence program in cells. Triggering cellular senescence could be a new therapeutic approach to limit tumor growth
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