13,349 research outputs found

    Metallic nanorings for broadband, enhanced extraction of light from solid-state emitters

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    We report on the increased extraction of light emitted by solid-state sources embedded within high refractive index materials. This is achieved by making use of a local lensing effect by sub-micron metallic rings deposited on the sample surface and centered around single emitters. We show enhancements in the intensity of the light emitted by InAs/GaAs single quantum dot lines into free space as high as a factor 20. Such a device is intrinsically broadband and therefore compatible with any kind of solid-state light source. We foresee the fabrication of metallic rings via scalable techniques, like nano-imprint, and their implementation to improve the emission of classical and quantum light from solid-state sources. Furthermore, while increasing the brightness of the devices, the metallic rings can also act as top contacts for the local application of electric fields for carrier injection or wavelength tuning.Comment: 10 pages, 3 figure

    A myth of the well-stirred model: Is the well-stirred model good for high clearance drugs?

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    Understanding the rationale of the well-stirred model (WSM), borrowed from chemical engineering, has been ongoing through the history of pharmacokinetics (PK) as an independent discipline. Extensive arguments around the WSM and 1977′s lidocaine data re-emerged recently. It was proposed that Pang and Rowland\u27s lidocaine data analysis was confounded by four intermingled confounding factors which may lead to contradictory conclusions or inconclusive dilemma. This re-visit of 1977′s lidocaine data analysis was challenged by Pang and coauthors. This commentary is our responses to their comments focusing on the lidocaine data analysis and the IVIVE by the WSM. In addition, the disadvantage of applying the well-stirred model in drug-drug interaction (DDI) prediction and a theoretical dilemma in the commonly used whole-body physiologically based pharmacokinetic (PBPK) models were discussed

    Cordyceps militaris Grown on Germinated Soybean Induces G2/M Cell Cycle Arrest through Downregulation of Cyclin B1 and Cdc25c in Human Colon Cancer HT-29 Cells

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    Cordyceps militaris (CM) is an insect-borne fungus that has been used in traditional Chinese medicine because of its wide range of pharmacological activities. In this paper, we studied CM grown on germinated soybean (GSC) and investigated the possible mechanisms underlying antiproliferative effect of GSC on HT-29 human colon cancer cells. In comparison with CM extracts and germinated soybean (GS) BuOH extracts, BuOH extracts of GSC showed remarkable inhibitory and antiproliferative effects on HT-29 colon cancer cells. After GSC treatment, HT-29 cells became smaller and irregular in shape. High G2/M phase cell populations were observed in the GSC-treated group. The levels of cyclin B1 and Cdc25 in the GSC-treated group were lower than those in the control group. These findings suggest that GSC BuOH extracts might act as an effective anti-proliferative agent by inducing G2/M cell cycle arrest in colon cancer cells

    Labisia pumila extract protects skin cells from photoaging caused by UVB irradiation

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    Labisia pumila (Myrsinaceae), known as "Kacip Fatimah," has been used by many generations of Malay women to induce and facilitate child birth as well as a post partum medicine. However, its topical application on skin has not been reported yet. In this study, we have focused on the anti-photoaging effects of L. pumila. Extract of L. pumila was first analyzed for their antioxidant activities using DPPH (2,2-diphenyl-1-picrylhydrazyl) since UV irradiation is a primary cause of reactive oxygen species (ROS) generation in the skin. The 50% free radical scavenging activity (FSC(50)) of L. pumila extract was determined to be 0.006%, which was equal to that produced by 156 microM ascorbic acid. TNF-alpha and cyclooxygenase (COX-2) play a primary role in the inflammation process upon UV irradiation and are known to be stimulated by UVB. Treatment with L. pumila extract markedly inhibited the TNF-alpha production and the expression of COX-2. Decreased collagen synthesis of human fibroblasts by UVB was restored back to normal level after treatment with L. pumila extract. On the other hand, the enhanced MMP-1 expression upon UVB irradiation was down regulated by L. pumila extract in a dose-dependent manner. Furthermore, treatment of normal keratinocytes with L. pumila extract attenuated UVB-induced MMP-9 expression. These results collectively suggest L. pumila extract has tremendous potential as an anti-photoaging cosmetic ingredient
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