Monolithic integration of light-emitting diodes and power metal-oxide-semiconductor channel high-electron-mobility transistors for light-emitting power integrated circuits in GaN on sapphire substrate

We report the demonstration of monolithically integrated light-emitting diodes (LEDs) and power metal-oxide-semiconductor channel high-electron-mobility transistors (HEMTs) in GaN. The structure comprised a direct epitaxial integration of layers typical for a GaN-based LED grown directly on top of the layers of a GaN-based HEMT. The layers were then fabricated into a serially connected pair of GaN LED and metal-oxide-semiconductor-gated 0.3 lm-channel HEMT by exposing the LED/HEMT epitaxial layers in selective area etching. The resulting monolithically integrated circuit shows a full gate voltage modulation of the light output power. This demonstrates compatibility of group-III nitride LED and HEMT processes. GaN-based high-power light-emitting diodes (LEDs) used in lighting applications typically require dedicated electronic driver circuits for AC-DC power conversion, current sourcing, and dimming using pulse-width modulation (PWM) or analog current control methods. 1 GaN power switching field-effect transistors (FETs), such as metaloxide-semiconductor (MOS) FETs, high-electron-mobility transistors (HEMTs), and MOS-Channel HEMTs (MOSCHEMTs) have shown outstanding performance in terms of high breakdown voltage (BV), low specific on-resistance, and high operating frequency, 2-4 and can be very useful as output devices for emerging applications of high power-high voltage LED systems. Ultimately, monolithic integration of GaN-based LEDs and GaN power HEMTs can reduce the cost and the size of solid state lighting systems, improve system reliability, and serve as a technology platform for the development of light-emitting power integrated circuits (LEPICs). LEPICs can also play an important role in adding functionalities required for emerging solid state lighting applications such as visible light communication (VLC) and other LED control technologies required for future smart lighting applications

Three-year monitoring of stable isotopes of precipitation at Concordia Station, East Antarctica

Past temperature reconstructions from Antarctic ice cores require a good quantification and understanding of the relationship between snow isotopic composition and 2m air or inversion (condensation) temperature. Here, we focus on the French-Italian Concordia Station, central East Antarctic plateau, where the European Project for Ice Coring in Antarctica (EPICA) Dome C ice cores were drilled. We provide a multi-year record of daily precipitation types identified from crystal morphologies, daily precipitation amounts and isotopic composition. Our sampling period (2008-2010) encompasses a warmer year (2009, +1.2 degrees C with respect to 2m air temperature long-term average 1996-2010), with larger total precipitation and snowfall amounts (14 and 76% above sampling period average, respectively), and a colder and drier year (2010, -1.8 degrees C, 4% below long-term and sampling period averages, respectively) with larger diamond dust amounts (49% above sampling period average). Relationships between local meteorological data and precipitation isotopic composition are investigated at daily, monthly and inter-annual scale, and for the different types of precipitation. Water stable isotopes are more closely related to 2m air temperature than to inversion temperature at all timescales (e.g. R-2 = 03 and 0.44, respectively for daily values). The slope of the temporal relationship between daily delta O-18 and 2m air temperature is approximately 2 times smaller (0.49 parts per thousand degrees C-1) than the average Antarctic spatial (0.8 parts per thousand degrees C-1) relationship initially used for the interpretation of EPICA Dome C records. In accordance with results from precipitation monitoring at Vostok and Dome F, deuterium excess is anticorrelated with delta O-18 at daily and monthly scales, reaching maximum values in winter. Hoar frost precipitation samples have a specific fingerprint with more depleted delta O-18 (about 5% below average) and higher deuterium excess (about 8% above average) values than other precipitation types. These datasets provide a basis for comparison with shallow ice core records, to investigate post-deposition effects. A preliminary comparison between observations and precipitation from the European Centre for Medium-RangeWeather Forecasts (ECMWF) reanalysis and the simulated water stable isotopes from the Laboratoire de Meteorologie Dynamique Zoom atmospheric general circulation model (LMDZiso) shows that models do correctly capture the amount of precipitation as well as more than 50% of the variance of the observed delta O-18, driven by large-scale weather patterns. Despite a warm bias and an underestimation of the variance in water stable isotopes, LMDZiso correctly captures these relationships between delta O-18, 2m air temperature and deuterium excess. Our dataset is therefore available for further in-depth model evaluation at the synoptic scale

Osteopontin induces growth of metastatic tumors in a preclinical model of non-small lung cancer

Osteopontin (OPN), also known as SPP1 (secreted phosphoprotein), is an integrin binding glyco-phosphoprotein produced by a variety of tissues. In cancer patients expression of OPN has been associated with poor prognosis in several tumor types including breast, lung, and colorectal cancers. Despite wide expression in tumor cells and stroma, there is limited evidence supporting role of OPN in tumor progression and metastasis. Using phage display technology we identified a high affinity anti-OPN monoclonal antibody (hereafter AOM1). The binding site for AOM1 was identified as SVVYGLRSKS sequence which is immediately adjacent to the RGD motif and also spans the thrombin cleavage site of the human OPN. AOM1 efficiently inhibited OPNa binding to recombinant integrin αvβ3 with an IC50 of 65 nM. Due to its unique binding site, AOM1 is capable of inhibiting OPN cleavage by thrombin which has been shown to produce an OPN fragment that is biologically more active than the full length OPN. Screening of human cell lines identified tumor cells with increased expression of OPN receptors (αvβ3 and CD44v6) such as mesothelioma, hepatocellular carcinoma, breast, and non-small cell lung adenocarcinoma (NSCLC). CD44v6 and αvβ3 were also found to be highly enriched in the monocyte, but not lymphocyte, subset of human peripheral blood mononuclear cells (hPBMCs). In vitro, OPNa induced migration of both tumor and hPBMCs in a transwell migration assay. AOM1 significantly blocked cell migration further validating its specificity for the ligand. OPN was found to be enriched in mouse plasma in a number of pre-clinical tumor model of non-small cell lung cancers. To assess the role of OPN in tumor growth and metastasis and to evaluate a potential therapeutic indication for AOM1, we employed a KrasG12D-LSLp53fl/fl subcutaneously implanted in vivo model of NSCLC which possesses a high capacity to metastasize into the lung. Our data indicated that treatment of tumor bearing mice with AOM1 as a single agent or in combination with Carboplatin significantly inhibited growth of large metastatic tumors in the lung further supporting a role for OPN in tumor metastasis and progression