PURPOSE Mesothelioma is an aggressive malignancy with heterogeneous outcomes that are partly driven by the differential efficacy of existing therapies across histologic types and sites of origin. Large-scale molecular analysis of mesothelioma and its subtypes has the potential to inform future therapeutic strategies. MATERIALS AND METHODS We analyzed 1,294 mesotheliomas {980 pleural (malignant pleural mesothelioma [MPM]) and 314 peritoneal (malignant peritoneal mesothelioma [MPeM])} using next-generation sequencing, determined programmed death ligand-1 (PD-L1) expression and histology in a subset of cases, and assessed MTAP /CDKN2A copy-number status by fluorescence in situ hybridization and T-cell infiltration in an independent cohort. RESULTS The molecular landscape of MPM was characterized by inactivating alterations in CDKN2A (49%), BAP1 (44%), CDKN2B (42%), MTAP (34%), and NF2 (33%). Compared with epithelioid MPM, nonepithelioid (ie, biphasic and sarcomatoid) MPM had identical tumor mutational burden (median 1.25 mut/Mb, P = .63), more commonly expressed PD-L1 (74% v 51%, P = .02), and was more likely to harbor MTAP, CDKN2A, and CDKN2B copy loss ( P < .05). Fluorescence in situ hybridization confirmed that homozygous MTAP loss was enriched in nonepithelioid MPM. Relative to MPM, MPeM had comparable tumor mutational burden and PD-L1 expression. The molecular profile of MPeM was similar to MPM, with the distinction that PBRM1 alterations occurred at higher frequency (16% v 7%, P < .01). ALK rearrangements were only observed in MPeM. CONCLUSION Regardless of histology and location, the molecular landscape of mesothelioma primarily consists of inactivating alterations in tumor suppressor genes, with enrichment of certain alterations in distinct subsets (eg, MTAP loss in nonepithelioid tumors). Given the limited efficacy of current therapies for this disease, novel approaches targeting recurring alterations should be explored.

InGaN-based light-emitting diodes (LEDs) grown on triangle-shaped patterned sapphire substrates were separated through a chemical lift-off process by laterally etching an AlN sacrificial layer at the GaN/sapphire substrate interface. After the epitaxial growth, an air-void structure was observed at the patterned region on the sapphire substrate that provided an empty space to increase the lateral etching rate of the AlN buffer layer. The lateral etching rate of the AlN buffer layer was calculated at 10 mu m/min for the 100-mu m-width LED chip that was lifted off from the sapphire substrate. A triangular-shaped hole structure and a hexagonal-shaped air-void structure were observed on the lift-off GaN surface that was transferred from the patterned sapphire substrate. Comparing to the LED/sapphire structure, a peak wavelength blueshift phenomenon of the micro-photoluminescence spectra was observed on the lifted off LED chip caused by the release of a compressive strain at the GaN/sapphire substrate interface. The chemical lift-off process was achieved by using an AlN buffer layer as a sacrificial layer in a hot potassium hydroxide solution. (C) 2010 The Japan Society of Applied Physic

InGaN light emitting diodes (LED) structure with an embedded 1/4λ-stack nanoporous-GaN/undoped-GaN distributed Bragg reflectors (DBR) structure have been demonstrated. Si-heavily doped GaN epitaxial layers (n+-GaN) in the 12-period n+-GaN/u-GaN stack structure are transformed into low refractive index nanoporous GaN structure through the doping-selective electrochemical wet etching process. The central wavelength of the nanoporous DBR structure was located at 442.3 nm with a 57 nm linewidth and a 97.1% peak reflectivity. The effective cavity length (6.0λ), the effective penetration depth (278 nm) in the nanoporous DBR structure, and InGaN active layer matching to Fabry-Pérot mode order 12 were observed in the far-field photoluminescence radiative spectra. High electroluminescence emission intensity and line-width narrowing effect were measured in the DBR-LED compared with the non-treated LED structure. Non-linear emission intensity and line-width reducing effect, from 11.8 nm to 0.73 nm, were observed by increasing the laser excited power. Resonant cavity effect was observed in the InGaN LED with bottom nanoporous-DBR and top GaN/air interface.

A high-efficiency InGaN light-emitting diode (LED) structure was grown on a silane (SiH 4 )-treated undoped-GaN layer with a thin in situ grown SiN x layer and a 3-D island structure. A lateral one-step epitaxial growth process was performed on the SiH 4 -treated GaN island structure to form a series-ofembedded-air-void (SEAV) structure. The SEAV structure prevented the dislocation from propagating to the top LED epitaxial layer that reduced the leakage current and increased the internal quantum efficiency of the treated InGaN LED. The light output power of the treated LED had a 68% enhancement compared with that of the standard LED at 20 mA. The high output power and the narrow divergent angle of the treated LED structure were caused by the high light scattering process on the SEAV structure.Index Terms-InGaN, series of embedded air voids (SEAV).

The InGaN-based light-emitting diodes (LEDs) with a roughened patterned backside on the N-face GaN surface were fabricated through a crystallographic etching process to increase light-extraction efficiency. After laser decomposition, laser scribing, and a lateral crystallographic wet etching process at the GaN/Al(2)O(3) interface, stable crystallographic etching planes were formed as the GaN {1011} planes that included an angle with the top GaN (0001) plane measured at 58 degrees. The GaN buffer layer acted as the sacrificial layer for the laser decomposition process and the lateral wet etching process with a 26 mu m/min etching rate. The LED with the inverted pyramidal N-face GaN surface close to the GaN/Al(2)O(3) interface has a larger light-scattering process than the conventional LED. The light-output power of the LED with the backside roughened surface had a 47% enhancement when measured in LED chip form