1,057,788 research outputs found

    D-brane categories

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    This is an exposition of recent progress in the categorical approach to D-brane physics. I discuss the physical underpinnings of the appearance of homotopy categories and triangulated categories of D-branes from a string field theoretic perspective, and with a focus on applications to homological mirror symmetry.Comment: 37 pages, IJMPA styl

    Light controlled photon tunneling

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    Recent measurements of photon tunneling through individual subwavelength pinholes in a gold film covered with a layer of polydiacetylene (Phys. Rev. Letters 88, 187402 (2002)) provided strong indication of "photon blockade" effect similar to Coulomb blockade phenomenon observed in single-electron tunneling experiments. Here we report first observation of photon tunneling been blocked (gated) by light at a different wavelength. This observation suggests possibility of building new class of photon tunneling gating devices for all-optical signal processing.Comment: 11 pages, 3 figure

    Far-field optical microscope with nanometer-scale resolution based on in-plane surface plasmon imaging

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    A new far-field optical microscopy technique capable of reaching nanometer-scale resolution has been developed recently using the in-plane image magnification by surface plasmon polaritons. This microscopy is based on the optical properties of a metal-dielectric interface that may, in principle, provide extremely large values of the effective refractive index n up to 100-1000 as seen by the surface plasmons. Thus, the theoretical diffraction limit on resolution becomes lambda/2n, and falls into the nanometer-scale range. The experimental realization of the microscope has demonstrated the optical resolution better than 50 nm for 502 nm illumination wavelength. However, the theory of such surface plasmon-based far-field microscope presented so far gives an oversimplified picture of its operation. For example, the imaginary part of the metal dielectric constant severely limits the surface-plasmon propagation and the shortest attainable wavelength in most cases, which in turn limits the microscope magnification. Here I describe how this limitation has been overcome in the experiment, and analyze the practical limits on the surface plasmon microscope resolution. In addition, I present more experimental results, which strongly support the conclusion of extremely high spatial resolution of the surface plasmon microscope.Comment: 23 pages, 9 figures, will be published in the topical issue on Nanostructured Optical Metamaterials of the Journal of Optics A: Pure and Applied Optics, Manuscript revised in response to referees comment

    Increasing transmission efficiency with advanced signal processing

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    Optical CDMA is an advanced and flexible communication technology with a potential to offer very energy efficient and highly scalable networking. In addition it can also deliver increased physical layer privacy and on-demand bandwidth sharing management. We have developed, extensively investigated, and experimentally demonstrated highly scalable approach to incoherent OCDMA which can very efficiently increase the number of simultaneous users. In addition, the introduction of an advanced photonic signal processing results in an overall system power budget improvement by nearly 3dB. Error-free operation with the BER less than 10-12 was achieved. We have also shown that with demonstrated approach we can dramatically improve number of simultaneous network users (up to ten times) while keeping the related hardware count unchanged. By comparing this results to DWDM concept, this substantial increase in number of simultaneous users did not require to add any additional wavelength laser sources and was achieved by employing just three communication wavelengths

    Cancer Clinical Trials Optimization and Pharmacogenomics

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    A critical overview of recent clinical trials in cancer is presented focused on signaling pathways blockers or inhibitors with a view to developing successful clinical trials employing personalized cancer therapies. Rational, pharmacogenomic strategies in cancer trials should be adopted that include specific molecular targeting based on adequate data for, and detailed modeling of, cancer cell genomes, modifications of cancer signaling pathways and epigenetic mechanisms. Novel translational oncogenomics research is rapidly expanding through the application of highly sensitive and specific advanced technology, research findings and computational tools and complex models to both pharmaceutical and clinical problems. Multiple sample analyses from several recent clinical studies have shown that gene expression data for cancer cells can be employed to distinguish between tumor types as well as to predict outcomes. Potentially important applications of such results are individualized human cancer therapies or, in general,'personalized medicine' that will have to be validated through optimally designed clinical trials in cancer. A Human Cancer Genomes and Epigenetics Project is proposed that can provide the essential data required for the optimal design of clinical trials with the goal of achieving significant improvements of the survival rates of cancer patients participating in clinical trials for advanced cancer stages. The results of such a six-year Human Cancer Genomes and Epigenetics Project should also greatly aid with the accelerated, rational development of effective anti-cancer medicines and the chemoprevention of cancers
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