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Wang, Qi

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Qi

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Wang, Qi
Author's Publications: search.filters.isAuthorOfPublication.9c9c2a39-3027-4204-9276-cd9f78c1826a

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Now showing 1 - 4 of 4
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    Deformed Microcavity Quantum Cascade Lasers with Directional Emission
    (Institute of Physics, 2009) Wang, Qi; Yan, Changling; Diehl, Laurent; Hentschel, Martina; Wiersig, Jan; Yu, Nanfang; Pflügl, Christian; Edamura, Tadataka; Yamanishi, Masamichi; Kan, Hirofumi; Belkin, Mikhail A.; Capasso, Federico
    We report the experimental realization of deformed microcavity quantum cascade lasers (QCLs) with a Limaçon-shaped chaotic resonator. Directional light emission with a beam divergence of \(\theta_{\|} \approx 33^{\circ}\) from QCLs emitting at λ ≈ 10µm was obtained in the plane of the cavity for deformations in the range 0.37 < ε < 0.43. An excellent agreement between measured and calculated far-field profiles was found. Both simulations and experiments show that the Limaçon-shaped microcavity preserves whispering gallery-like modes with high Q-factors for low deformations (ε < 0.50). In addition, while the measured spectra show a transition from whispering gallery-like modes to a more complex mode structure at higher pumping currents, we observed ‘universal far-field behavior’ for different intracavity mode distributions in the Limaçon microcavity, which can be explained by the distribution of unstable manifolds in ray optics simulations. Furthermore, the performance of the deformed microcavity lasers is robust with respect to variations of the deformation near its optimum value ε = 0.40, which implies that this structure reduces the requirements on photolithography fabrication. The successful realization of these microcavity lasers may lead to applications in optoelectronics.
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    Detection and Identification of NAP-2 as a Biomarker in Hepatitis B-Related Hepatocellular Carcinoma by Proteomic Approach
    (BioMed Central, 2008) He, Min; Qin, Jian; Zhai, Rihong; Wei, Xiao; Wang, Qi; Rong, Minhua; Jiang, Zhihua; Huang, Yuanjiao; Zhang, Zhiyong
    Background: A lack of sensitive and specific biomarkers is a major reason for the high rate of Primary hepatocellular carcinoma (HCC)-related mortality. The aim of this study was to investigate potential proteomic biomarkers specific for HCC. Methods: 81 patients with hepatitis B-related HCC and 33 healthy controls were randomly divided into a training set (33 HCC, 33 controls) and a testing set (48 HCC, 33 controls). Serum proteomic profiles were measured using Surface-enhanced laser desorption/ionization-time-of-flight mass spectroscopy (SELDI-TOF-MS).) A classification tree was established by Biomarker Pattern Software (BPS). Candidate SELDI peaks were isolated by tricine-SDS-PAGE, identified by HPLC-MS/MS and validated by immunohistochemistry (IHC) in liver tissues. Results: A total of 6 proteomic peaks (3157.33 m/z, 4177.02 m/z, 4284.79 m/z, 4300.80 m/z, 7789.87 m/z, and 7984.14 m/z) were chosen by BPS to establish a classification tree with the highest discriminatory power in the training set. The sensitivity and specificity of this classification tree were 95.92%, and 100% respectively in the testing set. A candidate marker of about 7984 m/z was isolated and identified as neutrophil-activating peptide 2 (NAP-2). IHC staining showed that NAP-2 signals were positive in HCC tissues but negative in adjacent tissues. Conclusion: The NAP-2 may be a specific proteomic biomarker of hepatitis B-related HCC.
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    Differential Sensitivity of Melanoma Cell Lines with BRAFV600E Mutation to the Specific Raf Inhibitor PLX4032
    (BioMed Central, 2010) Søndergaard, Jonas N; Nazarian, Ramin; Guo, Deliang; Hsueh, Teli; Mok, Stephen; Sazegar, Hooman; Barretina, Jordi G; Kehoe, Sarah M; Attar, Narsis; von Euw, Erika; Zuckerman, Jonathan E; Chmielowski, Bartosz; Comin-Anduix, Begoña; Koya, Richard C; Mischel, Paul S; Lo, Roger S; Ribas, Antoni; Wang, Qi; MacConaill, Laura
    Blocking oncogenic signaling induced by the BRAFV600E mutation is a promising approach for melanoma treatment. We tested the anti-tumor effects of a specific inhibitor of Raf protein kinases, PLX4032/RG7204, in melanoma cell lines. PLX4032 decreased signaling through the MAPK pathway only in cell lines with the BRAFV600E mutation. Seven out of 10 BRAFV600E mutant cell lines displayed sensitivity based on cell viability assays and three were resistant at concentrations up to 10 μM. Among the sensitive cell lines, four were highly sensitive with IC50 values below 1 μM, and three were moderately sensitive with IC50 values between 1 and 10 μM. There was evidence of MAPK pathway inhibition and cell cycle arrest in both sensitive and resistant cell lines. Genomic analysis by sequencing, genotyping of close to 400 oncogeninc mutations by mass spectrometry, and SNP arrays demonstrated no major differences in BRAF locus amplification or in other oncogenic events between sensitive and resistant cell lines. However, metabolic tracer uptake studies demonstrated that sensitive cell lines had a more profound inhibition of FDG uptake upon exposure to PLX4032 than resistant cell lines. In conclusion, BRAFV600E mutant melanoma cell lines displayed a range of sensitivities to PLX4032 and metabolic imaging using PET probes can be used to assess sensitivity.
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    Protein Aggregation and Protein Instability Govern Familial Amyotrophic Lateral Sclerosis Patient Survival
    (Public Library of Science, 2008) Agar, Jeffrey N.; Wang, Qi; Johnson, Joshua L.; Agar, Nathalie
    The nature of the “toxic gain of function” that results from amyotrophic lateral sclerosis (ALS)-, Parkinson-, and Alzheimer-related mutations is a matter of debate. As a result no adequate model of any neurodegenerative disease etiology exists. We demonstrate that two synergistic properties, namely, increased protein aggregation propensity (increased likelihood that an unfolded protein will aggregate) and decreased protein stability (increased likelihood that a protein will unfold), are central to ALS etiology. Taken together these properties account for 69% of the variability in mutant Cu/Zn-superoxide-dismutase-linked familial ALS patient survival times. Aggregation is a concentration-dependent process, and spinal cord motor neurons have higher concentrations of Cu/Zn-superoxide dismutase than the surrounding cells. Protein aggregation therefore is expected to contribute to the selective vulnerability of motor neurons in familial ALS.