1,024 research outputs found

    Stellar Image Interpretation System Using Artificial Neural Networks:

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    A supervised Artificial Neural Network (ANN) based system is being developed employing the Bi-polar function for identifying stellar images in CCD frames. It is based on feed-forward artificial neural networks with error back-propagation learning. It has been coded in C language. The learning process was performed on a 341 input pattern set, while a similar set was used for testing. The present approach has been applied on a CCD frame of the open star cluster M67. The results obtained have been discussed and compared with those derived in our previous work employing the Uni-polar function and by a package known in the astronomical community (DAOPHOT-II). Full agreement was found between the present approach, that of Elnagahy et al, and the standard astronomical data for the cluster. It has been shown that the developed technique resembles that of the Uni-Polar function, possessing a simple, much faster yet reliable approach. Moreover, neither prior knowledge on, nor initial data from, the frame to be analysed is required, as it is for DAOPHOT-II.

    The language of Einstein spoken by optical instruments

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    Einstein had to learn the mathematics of Lorentz transformations in order to complete his covariant formulation of Maxwell's equations. The mathematics of Lorentz transformations, called the Lorentz group, continues playing its important role in optical sciences. It is the basic mathematical language for coherent and squeezed states. It is noted that the six-parameter Lorentz group can be represented by two-by-two matrices. Since the beam transfer matrices in ray optics is largely based on two-by-two matrices or ABCDABCD matrices, the Lorentz group is bound to be the basic language for ray optics, including polarization optics, interferometers, lens optics, multilayer optics, and the Poincar\'e sphere. Because the group of Lorentz transformations and ray optics are based on the same two-by-two matrix formalism, ray optics can perform mathematical operations which correspond to transformations in special relativity. It is shown, in particular, that one-lens optics provides a mathematical basis for unifying the internal space-time symmetries of massive and massless particles in the Lorentz-covariant world.Comment: LaTex 8 pages, presented at the 10th International Conference on Quantum Optics (Minsk, Belarus, May-June 2004), to be published in the proceeding

    Automatic Fine Alignment and Pointing of Movable Telescopes using Point and Template Matching

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    Proceedings of the 2005 IEEE International Conference on Robotics and Biomimetic

    Understanding the Role of Innate Immune Cells and Identifying Genes in Breast Cancer Microenvironment

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    The innate immune system is the first line of defense against invading pathogens and has a major role in clearing transformed cells, besides its essential role in activating the adaptive immune system. Macrophages, dendritic cells, NK cells, and granulocytes are part of the innate immune system that accumulate in the tumor microenvironment such as breast cancer. These cells induce inflammation in situ by secreting cytokines and chemokines that promote tumor growth and progression, in addition to orchestrating the activities of other immune cells. In breast cancer microenvironment, innate immune cells are skewed towards immunosuppression that may lead to tumor evasion. However, the mechanisms by which immune cells could interact with breast cancer cells are complex and not fully understood. Therefore, the importance of the mammary tumor microenvironment in the development, growth, and progression of cancer is widely recognized. With the advances of using bioinformatics and analyzing data from gene banks, several genes involved in NK cells of breast cancer individuals have been identified. In this review, we discuss the activities of certain genes involved in the cross-talk among NK cells and breast cancer. Consequently, altering tumor immune microenvironment can make breast tumors more responsive to immunotherapy

    Optical Investigations of Charge Gap in Orbital Ordered La1/2Sr3/2MnO4

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    Temperature and polarization dependent electronic structure of La1/2Sr3/2MnO4 were investigated by optical conductivity analyses. With decreasing temperature, for E//ab, a broad mid-infrared (MIR) peak of La1/2Sr3/2MnO4 becomes narrower and moves to the higher frequency, while that of Nd1/2Sr3/2MnO4 nearly temperature independent. We showed that the MIR peak in La1/2Sr3/2MnO4 originates from orbital ordering associated with CE-type magnetic ordering and that the Jahn-Teller distortion has a significant influence on the width and the position of the MIR peak.Comment: 10 pages, 4 figure

    Molecular examination of differentially expressed genes in the brains of experimental autoimmune encephalomyelitis mice post herceptin treatment

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    Objective: Herceptin (trastuzumab) is an approved drug for treating HER2+ breast cancer patients, but its use for other diseases is not established. We sought to investigate the effects of Herceptin on ameliorating experimental autoimmune encephalomyelitis (EAE) and to examine its effects on the expression of various genes. Methods: We used in-silico analysis of publicly available data, qRT-PCR, and immunohisto-chemistry (IHC) to determine the expression of HER2+ cells in the brains of EAE mice. IHC was also utilized to determine the anti-inflammatory effects of Herceptin. The ability of Herceptin to alleviate the EAE clinical score was measured in these mice. Bioinformatics analysis of publicly available data and qRT-PCR were performed to investigate the differentially expressed genes that were either up-regulated or down-regulated during the high clinical score (HCS) of the disease. Results: We observed that HER2/Erbb2, the receptor for Herceptin is upregulated in the brains of EAE mice when the brains were examined at the HCS stage. Further, we demonstrated that Herceptin ameliorates the EAE disease, increasing re-myelination, reducing brain inflammation, CD3+ T cell accumulation, and HER2+ cells in the brains of these mice. Molecular analysis demonstrated the expression of different genes that were either up-regulated or down-regulated during the HCS of the disease. Our combined bioinformatics and qRT-PCR analyses show increased mRNA expression of Atp6v0d2, C3, C3ar1, Ccl3, Ccl6, Cd74, Clec7a, Cybb, H2-Aa, Hspb1, Lilr4b, Lilrb4a, Mpeg1, Ms4a4a, Ms4a6c, Saa3, Serpina3n and Timp1, at HCS. Except for the mRNA levels of Cd74 and Clec7a which were increased at HCS when Herceptin was used in both prophylactic and therapeutic regimens, the levels of other described mRNAs were reduced. Conclusion: These novel findings show that Herceptin ameliorates the clinical score in EAE mice and are the first to investigate in detail the differential gene expression post-treatment with the drug.</p

    Molecular examination of differentially expressed genes in the brains of experimental autoimmune encephalomyelitis mice post herceptin treatment

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    Objective: Herceptin (trastuzumab) is an approved drug for treating HER2+ breast cancer patients, but its use for other diseases is not established. We sought to investigate the effects of Herceptin on ameliorating experimental autoimmune encephalomyelitis (EAE) and to examine its effects on the expression of various genes. Methods: We used in-silico analysis of publicly available data, qRT-PCR, and immunohisto-chemistry (IHC) to determine the expression of HER2+ cells in the brains of EAE mice. IHC was also utilized to determine the anti-inflammatory effects of Herceptin. The ability of Herceptin to alleviate the EAE clinical score was measured in these mice. Bioinformatics analysis of publicly available data and qRT-PCR were performed to investigate the differentially expressed genes that were either up-regulated or down-regulated during the high clinical score (HCS) of the disease. Results: We observed that HER2/Erbb2, the receptor for Herceptin is upregulated in the brains of EAE mice when the brains were examined at the HCS stage. Further, we demonstrated that Herceptin ameliorates the EAE disease, increasing re-myelination, reducing brain inflammation, CD3+ T cell accumulation, and HER2+ cells in the brains of these mice. Molecular analysis demonstrated the expression of different genes that were either up-regulated or down-regulated during the HCS of the disease. Our combined bioinformatics and qRT-PCR analyses show increased mRNA expression of Atp6v0d2, C3, C3ar1, Ccl3, Ccl6, Cd74, Clec7a, Cybb, H2-Aa, Hspb1, Lilr4b, Lilrb4a, Mpeg1, Ms4a4a, Ms4a6c, Saa3, Serpina3n and Timp1, at HCS. Except for the mRNA levels of Cd74 and Clec7a which were increased at HCS when Herceptin was used in both prophylactic and therapeutic regimens, the levels of other described mRNAs were reduced. Conclusion: These novel findings show that Herceptin ameliorates the clinical score in EAE mice and are the first to investigate in detail the differential gene expression post-treatment with the drug.</p
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