813 research outputs found

    The impact of Arctic sea ice loss on mid-Holocene climate.

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    Mid-Holocene climate was characterized by strong summer solar heating that decreased Arctic sea ice cover. Motivated by recent studies identifying Arctic sea ice loss as a key driver of future climate change, we separate the influences of Arctic sea ice loss on mid-Holocene climate. By performing idealized climate model perturbation experiments, we show that Arctic sea ice loss causes zonally asymmetric surface temperature responses especially in winter: sea ice loss warms North America and the North Pacific, which would otherwise be much colder due to weaker winter insolation. In contrast, over East Asia, sea ice loss slightly decreases the temperature in early winter. These temperature responses are associated with the weakening of mid-high latitude westerlies and polar stratospheric warming. Sea ice loss also weakens the Atlantic meridional overturning circulation, although this weakening signal diminishes after 150-200 years of model integration. These results suggest that mid-Holocene climate changes should be interpreted in terms of both Arctic sea ice cover and insolation forcing

    Vision-Inspection System for Residue Monitoring of Ready-Mixed Concrete Trucks

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    The objective of this study is to propose a vision-inspection system that improves the quality management for ready-mixed concrete (RMC). The proposed system can serve as an alternative to the current visual inspection method for the detection of residues in agitator drum of RMC truck. To propose the system, concept development and the system-level design should be executed. The design considerations of the system are derived from the hardware properties of RMC truck and the conditions of RMC factory, and then 6 major components of the system are selected in the stage of system level design. The prototype of system was applied to a real RMC plant and tested for verification of its utility and efficiency. It is expected that the proposed system can be employed as a practical means to increase the efficiency of quality management for RMC

    Improvement of photon extraction efficiency of GaN-based LED using micro and nano complex polymer structures

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    A micro- and nanoscale complex structure made of a high refractive index polymer (n = 2.08) was formed on the ITO electrode layer of an edge-emitting type GaN blue light-emitting diode (LED), in order to improve the photon extraction efficiency by suppressing total internal reflection of photons. The nanoimprint lithography process was used to form the micro- and nanoscale complex structures, using a polymer resin with dispersed TiO2 nano-particles as an imprint resin. Plasma processing, such as reactive ion etching, was used to form the micro- and nano-scale complex structure; thus, plasma-induced damage to the LED device can be avoided. Due to the high refractive index polymeric micro- and nanostructure on the ITO layer, the electroluminescence emission was increased up to 20%, compared to an identical LED that was grown on a patterned sapphire substrate to improve photon extraction efficiency

    Identification of Gene Expression Signature Modulated by Nicotinamide in a Mouse Bladder Cancer Model

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    BACKGROUND: Urinary bladder cancer is often a result of exposure to chemical carcinogens such as cigarette smoking. Because of histological similarity, chemically-induced rodent cancer model was largely used for human bladder cancer studies. Previous investigations have suggested that nicotinamide, water-soluble vitamin B3, may play a key role in cancer prevention through its activities in cellular repair. However, to date, evidence towards identifying the genetic alterations of nicotinamide in cancer prevention has not been provided. Here, we search for the molecular signatures of cancer prevention by nicotinamide using a N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced urinary bladder cancer model in mice. METHODOLOGY/PRINCIPAL FINDINGS: Via microarray gene expression profiling of 20 mice and 233 human bladder samples, we performed various statistical analyses and immunohistochemical staining for validation. The expression patterns of 893 genes associated with nicotinamide activity in cancer prevention were identified by microarray data analysis. Gene network analyses of these 893 genes revealed that the Myc and its associated genes may be the most important regulator of bladder cancer prevention, and the gene expression signature correlated well with protein expression data. Comparison of gene expression between human and mouse revealed that BBN-induced mouse bladder cancers exhibited gene expression profiles that were more similar to those of invasive human bladder cancers than to those of non-invasive human bladder cancers. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that nicotinamide plays an important role as a chemo-preventive and therapeutic agent in bladder cancer through the regulation of the Myc oncogenic signature. Nicotinamide may represent a promising therapeutic modality in patients with muscle-invasive bladder cancer
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