Protein arginine methylation is a post-translational modification that has been implicated in signal transduction, gene transcription, DNA repair and RNA processing. Overexpression or deregulation of protein arginine methyltransferases (PRMTs) have been reported to be associated with various cancers but have not been studied in head and neck cancer (HNC). We investigated the involvement of the modification in HNC using oral cancer cell lines (SAS, OECM-1 and HSC-3) and an immortalized normal oral cells (S-G). The expression levels of the predominant PRMT1 were generally consistent with the levels of asymmetric dimethylarginine (ADMA), highest in SAS and OECM1, then S-G and low in HSC-3. Upon the treatment with an indirect methyltransferase inhibitor adenosine dialdehyde (AdOx), the ADMA levels in SAS and OECM1, but not that in S-G and HSC-3, decreased significantly. SAS and OECM with high ADMA levels grew faster than HSC-3 and S-G. The growth rate of the fast growing SAS and OECM, but not that of the other two cell lines, decreased significantly upon AdOx treatment. The migration activity of SAS and HSC-3, two cell lines with migration ability also decreased after the AdOx treatment. Immunohistochemical analyses of specimens from typical HNC patients showed strong PRMT1 expression in the tumor cells compared with neighboring normal cells. Knockdown of PRMT1 in SAS cells decreased the levels of PRMT1 and ADMA-containing proteins significantly. These cells showed decreased growth rate, reduced migration activity but increased expression of the epithelial marker E-cadherin. The present study thus provides fundamental background for evaluation of the PRMT1 gene as the therapeutic targets of HNC.

Abstract-The Antarctic continent is an extremely suitable environment for the application of remote sensing technology as it is one of the harshest places on earth. Satellite images of the terrain can be properly interpreted with thorough understanding of the microwave scattering process. The proper model development for backscattering can be used to test the assumptions on the dominating scattering mechanisms. In this paper, the formulation and analysis of a multilayer model used for sea ice terrain is presented. The multilayer model is extended from the previous single layer model developed based on the Radiative Transfer theory. The Radiative Transfer theory is chosen because of its simplicity and ability to incorporate multiple scattering effects into the calculations. The propagation of energy in the medium is characterized by the extinction and phase matrices. The model also incorporates the Dense Medium Phase and Amplitude Correction Theory (DM-PACT) where it takes into account the close spacing effect among scatterers. The air-snow interface, snow-sea ice interface and sea ice-ocean interface are modelled using the Integral Equation Method (IEM). The simulated backscattering coefficients for co-and cross-polarization using the developed model for 1 GHz and 10 GHz are presented. In addition, the simulated backscattering coefficients from the multilayer model were compared with the measurement results obtained from Coordinated Eastern Artic Experiment (CEAREX) (Grenfell, 1992) and with the results obtained from the model developed by Saibun Tjuatja (based on the Matrix Doubling method) in 1992.

Abstract-In this study, an inverse microwave scattering model for sea ice has been developed for the purpose of sea ice thickness retrieval using radar backscatter data. The model is loosely based on the Radiative-Transfer-Thermodynamic Inverse Model for Sea Ice Thickness Retrieval from Time-Series Scattering Data. The developed inverse model is a combination of the Radiative Transfer Theory with Dense Medium Phase and Amplitude Correction Theory (RT-DMPACT) forward model and the Levenberg-Marquardt Optimization algorithm. Using input data from ground truth measurements carried out in Ross Island, Antarctica, together with radar backscatter data extracted from purchased satellite images, the sea ice thickness of an area is estimated using the inverse model developed. The estimated sea ice thickness is then compared with the ground truth measurement data to verify its accuracy. The results have shown good promise, with successful estimation of the sea ice thickness within ±0.15 m of the actual measurement. A theoretical analysis has also revealed that the model faces difficulty once the sea ice thickness exceeds 1.7 m. This can be considered in the future development and improvement of the model.

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High quality factor (Q) photonic devices in the room temperature thermal infrared region, corresponding to deeper long-wave infrared with wavelengths beyond 9 microns, have been demonstrated for the first time. Whispering gallery mode diamond microresonators were fabricated using single crystal diamond substrates and oxygen-based inductively coupled plasma (ICP) reactive ion etching (RIE) at high angles. The spectral characteristics of the devices were probed at room temperature using a tunable quantum cascade laser that was free space-coupled into the resonators. Light was extracted via an arsenic selenide (As2Se3) chalcogenide infrared fiber and directed to a cryogenically cooled mercury cadmium telluride (HgCdTe) detector. The quality factors were tested in multiple microresonators across a wide spectral range from 9 to 9.7 microns with similar performance. One example resonance (of many comparables) was found to reach 3648 at 9.601 µm. Fourier analysis of the many resonances of each device showed free spectral ranges slightly greater than 40 GHz, matching theoretical expectations for the microresonator diameter and the overlap of the whispering gallery mode with the diamond.