5,344 research outputs found

    Chemical Printing of Biological Tissue by Gold Nanoparticle-Assisted Laser Ablation

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    Optical characteristics of GAN/SI micro-pixel light-emitting diode arrays

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    Two-dimensional arrays of emissive micro-light-emitting diodes (μ-LEDS) have been developed for a variety of applications such as high resolution micro-displays, maskless photo-lithography and multichannel visible-light optical communications amongst others. μ-LEDs have traditionally been fabricated on InGaN LED wafers grown on transparent sapphire substrates, and have suffered from optical crosstalk issues. When a single pixel is addressed, adjacent pixels and regions appear illuminated simultaneously. Such problems could result in functional failure in high-density μ-LED applications, including reduced resolution of micro-display and decreased signal-to-noise ratio in ...postprin

    The effects of stent porosity on the endovascular treatment of intracranial aneurysms located near a bifurcation

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    Computational fluid dynamics study of bifurcation aneurysms treated with pipeline embolization device: side branch diameter study

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    An intracranial aneurysm, abnormal swelling of the cerebral artery, may lead to undesirable rates of mortality and morbidity upon rupture. Endovascular treatment involves the deployment of a flow-diverting stent that covers the aneurysm orifice, thereby reducing the blood flow into the aneurysm and mitigating the risk of rupture. In this study, computational fluid dynamics analysis is performed on a bifurcation model to investigate the change in hemodynamics with various side branch diameters. The condition after the deployment of a pipeline embolization device is also simulated. Hemodynamic factors such as flow velocity, pressure, and wall shear stress are studied. Aneurysms with a larger side branch vessel might have greater risk after treatment in terms of hemodynamics. Although a stent could lead to flow reduction entering the aneurysm, it would drastically alter the flow rate inside the side branch vessel. This may result in side-branch hypoperfusion subsequent to stenting. In addition, two patient-specific bifurcation aneurysms are tested, and the results show good agreement with the idealized models. Furthermore, the peripheral resistance of downstream vessels is investigated by varying the outlet pressure conditions. This quantitative analysis can assist in treatment planning and therapeutic decision-making.published_or_final_versio

    University and College Admission Policies and Practices in Hong Kong: Opportunities and Challenges in Moving from Secondary to Tertiary Education

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    Conference Theme: Transition to a Better and Higher LearningTopic II: The Transition from Secondary to Higher Education : Case study presentationsⅠpublished_or_final_versio

    Elevated TAK1 augments tumor growth and metastatic capacities of ovarian cancer cells through activation of NF-κB signaling

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    Transforming growth factor (TGF)-β-activating kinase 1 (TAK1) is a serine/threonine kinase which is frequently associated with human cancer progression. However, its functional role in tumorigenesis is still controversial. Here, we report that TAK1 enhances the oncogenic capacity of ovarian cancer cells through the activation of NF-κB signaling. We found that TAK1 is frequently upregulated and significantly associated with high-grade and metastatic ovarian cancers. Mechanistic studies showed that Ser412 phosphorylation is required for TAK1 in activating NF-κB signaling and promotes aggressiveness of ovarian cancer cells. Conversely, suppression of TAK1 activity by point mutation at Ser412, RNAi mediated gene knockdown or TAK1 specific inhibitor ((5Z) -7-Oxozeaenol) remarkably impairs tumor growth and metastasis in ovarian cancer in vitro and in vivo. Our study underscores the importance of targeting TAK1 as a promising therapeutic approach to counteract the ovarian cancer progression.published_or_final_versio

    Controlling Curie temperature in (Ga,Ms)As through location of the Fermi level within the impurity band

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    The ferromagnetic semiconductor (Ga,Mn)As has emerged as the most studied material for prototype applications in semiconductor spintronics. Because ferromagnetism in (Ga,Mn)As is hole-mediated, the nature of the hole states has direct and crucial bearing on its Curie temperature TC. It is vigorously debated, however, whether holes in (Ga,Mn)As reside in the valence band or in an impurity band. In this paper we combine results of channeling experiments, which measure the concentrations both of Mn ions and of holes relevant to the ferromagnetic order, with magnetization, transport, and magneto-optical data to address this issue. Taken together, these measurements provide strong evidence that it is the location of the Fermi level within the impurity band that determines TC through determining the degree of hole localization. This finding differs drastically from the often accepted view that TC is controlled by valence band holes, thus opening new avenues for achieving higher values of TC.Comment: 5 figures, supplementary material include
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