| 1. |
- Scandale, Walter, et al.
(författare)
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Apparatus to study crystal channeling and volume reflection phenomena at the SPS H8 beamline
- 2008
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 79:2
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Tidskriftsartikel (refereegranskat)abstract
- A high performance apparatus has been designed and built by the H8-RD22 collaboration for the study of channeling and volume reflection phenomena in the interaction of 400 GeVc protons with bent silicon crystals, during the 2006 data taking in the external beamline H8 of the CERN SPS. High-quality silicon short crystals were bent by either anticlastic or quasimosaic effects. Alignment with the highly parallel (8 μrad divergence) proton beam was guaranteed through a submicroradian goniometric system equipped with both rotational and translational stages. Particle tracking was possible by a series of silicon microstrip detectors with high-resolution and a parallel plate gas chamber, triggered by various scintillating detectors located along the beamline. Experimental observation of volume reflection with 400 GeVc protons proved true with a deflection angle of (10.4±0.5) μrad with respect to the unperturbed beam, with a silicon crystal whose (111) planes were parallel to the beam. © 2008 American Institute of Physics.
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| 2. |
- Scandale, Walter, et al.
(författare)
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Deflection of 400GeV/c proton beam with bent silicon crystals at the CERN Super Proton Synchrotron
- 2008
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Ingår i: Physical Review Special Topics - Accelerators and Beams. - 1098-4402. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a detailed study of the deflection phenomena of a 400GeV/c proton beam impinging on a new generation of bent silicon crystals; the tests have been performed at the CERN Super Proton Synchrotron H8 beam line. Channeling and volume reflection angles are measured with an extremely precise goniometer and with high resolution silicon microstrip detectors. Volume reflection has been observed and measured for the first time at this energy, with a single-pass efficiency as large as 98%, in good agreement with the simulation results. This efficiency makes volume reflection a possible candidate for collimation with bent crystals at the CERN Large Hadron Collider. © 2008 The American Physical Society.
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| 3. |
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| 4. |
- Afanasiev, Sergey V., et al.
(författare)
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Experimental apparatus to study crystal channeling in an external SPS beamline
- 2007
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Ingår i: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 6634
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Tidskriftsartikel (refereegranskat)abstract
- For the new generation of high intensity hadronic machines as, for instance, LHC, halo collimation is a necessary issue for the accelerator to operate at the highest possible luminosity and to prevent the damage of superconductor magnets.1 We propose an experiment aimed to systematic study of the channeling phenomenology and of the newly observed "volume reflection" effect. This experiment will be performed for an external SPS beamline and will make use of a primary proton beam with 400 GeV/c momentum and very small (∼ 3 μrad) divergence. The advantage of a proposed experiment is precise tracking of particles that interacted with a crystal, so that to determine the single-pass efficiency for all the processes involved. For this purpose, a telescope equipped with high-resolution silicon microstrip detectors will be used. New generation silicon crystals and an extra-precise goniometer are mandatory issues. Main goal of the experiment is to get the precise information on channeling of relativistic particles and, ultimately, on the feasibility of such technique for halo collimation at LHC. In this contribution we review the status of the setting-up of experimental apparatus and its future development in sight of the planned run in September 2006.
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| 5. |
- Dremov, Viacheslav V., et al.
(författare)
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Local Josephson vortex generation and manipulation with a Magnetic Force Microscope
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Josephson vortices play an essential role in superconducting quantum electronics devices. Often seen as purely conceptual topological objects, 2π-phase singularities, their observation and manipulation are challenging. Here we show that in Superconductor—Normal metal—Superconductor lateral junctions Josephson vortices have a peculiar magnetic fingerprint that we reveal in Magnetic Force Microscopy (MFM) experiments. Based on this discovery, we demonstrate the possibility of the Josephson vortex generation and manipulation by the magnetic tip of a MFM, thus paving a way for the remote inspection and control of individual nano-components of superconducting quantum circuits.
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| 6. |
- Baranov, Vladimir, et al.
(författare)
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Carcinoembryonic antigen (CEA) and CEA-related cell adhesion molecule 1 (CEACAM1), apically expressed on human colonic M cells, are potential receptors for microbial adhesion.
- 2004
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 121:2, s. 83-9
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Tidskriftsartikel (refereegranskat)abstract
- In the human gut mucosa, specialized M cells deliver intact foreign macromolecules and commensal bacteria from the lumen to organized mucosal lymphoid tissues triggering immune responses. M cells are also major sites of adhesion and invasion for enteric pathogens. The molecular features of M cell apical surfaces that promote microbial normal attachment are still largely unknown. We have demonstrated previously that in the human colonic epithelium, carcinoembryonic antigen (CEA) and CEA-related cell adhesion molecule 1 (CEACAM1) are integral components of the apical glycocalyx which participate in epithelial-microbial interactions. In this study, based on the reactivity of specific monoclonal antibodies and on immunoelectron microscopy, we show that M cells of human colonic solitary lymphoid follicles express CEA and CEACAM1 on the apical surface. Recently these highly glycosylated molecules have been characterized as protein receptors for different bacteria. This leads us to propose a role for CEA and CEACAM1 in the adherence of enteric bacteria to the apical membrane of colonic M cells. We also hypothesize that, unlike colonic enterocytes, M cells lack the defense mechanism that eliminates CEA and CEACAM1 upon microbial binding and which is based on vesiculation of microvillus plasma membrane.
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| 7. |
- Baranov, Vladimir, et al.
(författare)
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Expression of carcinoembryonic antigen and nonspecific cross-reacting 50-kDa antigen in human normal and cancerous colon mucosa : comparative ultrastructural study with monoclonal antibodies
- 1994
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 54:12, s. 3305-3314
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Tidskriftsartikel (refereegranskat)abstract
- The precise localization of carcinoembryonic antigen (CEA) and non-specific cross-reacting 50-kDa antigen (NCA 50) in normal colon mucosa and colon adenocarcinoma was investigated by using an indirect immunoperoxidase electron microscopic technique with specific monoclonal antibodies. In normal adult colon both antigens were localized to microvesicles and filaments of the "fuzzy coat" on the apical surface of the epithelial cells. In addition, NCA 50 was found in the narrow spaces between adjoining microvilli. Mature columnar cells at the free luminal surface contained most of the antigen positive material. CEA and NCA 50 were also detected as intracellular components of goblet cells. In multilayered tumor glands, the cell surface expression of the antigens was dependent on the position of the tumor cell in the gland. The neoplastic cells showed either a predominant apical labeling or a positive staining of almost the entire cell surface. Some of the neoplastic cells contained CEA in so-called "intracellular lumina." In contrast to normal colon epithelial cells most tumor cells synthesized NCA 50 actively. In normal colonic mucosa, unlike in cancerous tissue, CEA and NCA 50 appear to be released via vesicles formed from the microvillous membrane of mature columnar cells. These results are consistent with the hypothesis that CEA and NCA play a role in the nonspecific defense against microorganisms in the large intestine.
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| 8. |
- Baranov, Vladimir, et al.
(författare)
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Lipids are a constitutive component of cytolytic granules.
- 2000
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Ingår i: Histochemistry and Cell Biology. - 0948-6143 .- 1432-119X. ; 114:2, s. 167-71
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Tidskriftsartikel (refereegranskat)abstract
- Cytolytic granules are specific organelles of activated cytotoxic lymphocytes mediating storage and regulated excretion of lytic molecules for killing of target cells. A variety of the other granule components may also participate in granule-mediated cytotoxicity. In this study, the subcellular localization of lipids in the granules of human decidual CD56+ natural killer-like cells was determined by staining with malachite green aldehyde and imidazole-buffered osmium tetroxide. Lipids were shown, for the first time, to be a constitutive component of cytolytic granules. Lipids formed an additional structural microdomain, located between the granule-limiting membrane and the granule core. Images of the granules on serial sections suggested that intragranular lipids wrap the core. We speculate that granule lipids participate in packing of lytic molecules inside the granules, in autocrine signaling ending granule secretion, and in the killing process.
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| 9. |
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| 10. |
- Fahlgren, Anna, et al.
(författare)
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Interferon-gamma tempers the expression of carcinoembryonic antigen family molecules in human colon cells : a possible role in innate mucosal defence.
- 2003
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Ingår i: Scandinavian Journal of Immunology. - 0300-9475 .- 1365-3083. ; 58:6, s. 628-41
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Tidskriftsartikel (refereegranskat)abstract
- Four carcinoembryonic antigen-related cell adhesion molecule (CEACAM)s, i.e. CEA, CEACAM1, CEACAM6 and CEACAM7, are localized to the apical glycocalyx of normal colonic epithelium and have been suggested to play a role in innate immunity. The expression of these molecules in colon carcinoma cells was studied at the mRNA and protein levels after treatment with interferon-gamma (IFN-gamma), interleukin-1beta, live bacteria or lipopolysaccharide. The colon carcinoma cell lines LS174T and HT-29 were studied in detail using real-time quantitative reverse transcriptase-polymerase chain reaction, immunoflow cytometry and immunoelectron microscopy. IFN-gamma, but not the other agents, modified expression of CEA, CEACAM1 and CEACAM6. None of the agents upregulated CEACAM7 expression. Two expression patterns were seen. HT-29 cells, which initially showed low quantities of mRNAs and proteins, displayed marked upregulation of both mRNAs and proteins. LS174T cells transcribed stable high levels of mRNA before and after treatment. Additionally, IFN-gamma induced increased cell surface expression of CEA, CEACAM1 and CECAM6. IFN-gamma has two important effects on the expression levels of the CEA family molecules in colon epithelial cells: direct upregulation of CEACAM1 and promotion of cell differentiation resulting in increased expression of CEA and CEACAM6 and decreased expression of CEACAM7.
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