662 research outputs found

    MIMAC : A micro-tpc matrix for directional detection of dark matter

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    Directional detection of non-baryonic Dark Matter is a promising search strategy for discriminating WIMP events from background. However, this strategy requires both a precise measurement of the energy down to a few keV and 3D reconstruction of tracks down to a few mm. To achieve this goal, the MIMAC project has been developed. It is based on a gaseous micro-TPC matrix, filled with CF4 and CHF3. The first results on low energy nuclear recoils (H, F) obtained with a low mono-energetic neutron field are presented. The discovery potential of this search strategy is discussed and illustrated by a realistic case accessible to MIMAC.Comment: 6 pages, Proc. of the fifth international symposium on large TPCs for low energy rare event detection, Paris, France, Dec. 2010. To appear in Journal of Physic

    Fine Needle Aspiration Cytology of Metastatic Plasmacytoid Urothelial Carcinoma- Report of Four Cases Including a Case of Mixed Plasmacytoid and Micropapillary Morphology

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    Objectives: The aim of this study was to report a small series of fine-needle aspiration (FNA) cytology of the plasmacytoid variant of urothelial carcinoma (PVUC). Study Design: A computerized search of our laboratory information system was performed for the 5-year period between January 2008 and January 2013 to identify all FNA cases in which the corresponding surgical pathology cases were diagnosed as PVUC. Results: The 4 cases identified were from 2 men (aged 56 and 64 years) and 2 women (aged 72 and 46 years). The FNA smears demonstrated low-to-moderate cellularity and consisted predominantly of single and dyshesive, medium-sized tumor cells with eccentrically located nuclei and a moderate-to-abundant dense cytoplasm. The nuclei were oval with slightly irregular nuclear membranes and contained coarse granular chromatin with inconspicuous or small nucleoli. There was moderate nuclear variation in size. The nuclear-to-cytoplasmic ratio ranged from <1 to 3. Binucleation, cytoplasmic vacuoles, and perinuclear hof were occasionally seen. Conclusions: FNA cytology of PVUC shares features with plasma cell neoplasms, lobular carcinoma of the breast, and signet ring cell carcinoma of the stomach. Being aware of the patient's clinical history and the potential diagnostic pitfall of this rare variant of urothelial carcinoma is important for an accurate diagnosis on FNA biopsy

    Dark matter directional detection with MIMAC

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    MiMac is a project of micro-TPC matrix of gaseous (He3, CF4) chambers for direct detection of non-baryonic dark matter. Measurement of both track and ionization energy will allow the electron-recoil discrimination, while access to the directionnality of the tracks will open a unique way to distinguish a geniune WIMP signal from any background. First reconstructed tracks of 5.9 keV electrons are presented as a proof of concept.Comment: 4 pages, proc. of the 44th Rencontres De Moriond: Electroweak Interactions And Unified Theories, 7-14 Mar 2009, La Thuile, Ital

    The application of the Johns Hopkins Hospital Template on urine cytology

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    Background To evaluate the utility of the Johns Hopkins Hospital (JHH) template in detection of high-grade urothelial carcinoma (HGUC). Methods A computerized search of our laboratory information system was performed for all urine cytology cases from 2009 to 2011 processed by the SurePath™. We included only cases with correlating surgical pathology within 6 months after the urinary samples were obtained. The original cytologic diagnoses were reclassified according to the JHH template, and these cytolog ic diagnoses were then correlated with the follow-up surgical pathology diagnoses. Results A total of 273 urine samples with histopathologic follow-up were identified. The reclassified cytologic diagnoses included negative for urothelial atypia or malignancy (NUAM) 110; atypical urothelial cells of undetermined significance (AUC-US) 83; atypical urothelial cells, cannot exclude high-grade urothelial carcinoma (AUC-H) 49; HGUC 29; and low-grade urothelial carcinoma (LGUC) 2. More than one-half of patients (58%) who had biopsy-confirmed high-grade urothelial lesions had a preceding cytologic diagnosis of AUC-H or HGUC. AUC-H and HGUC are associated with high-grade urothelial lesions in 80% and 90% of the cases and show statistical significance when compared with AUC-US or NUAM (P < 0.05). Conclusion The JHH template is useful and effective in identifying patients with high-grade urothelial lesions who need to undergo cystoscopy. Diagn. Cytopathol. 2015;43:593–597. © 2015 Wiley Periodicals, Inc

    Micromegas micro-TPC for direct Dark Matter search with MIMAC

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    The MIMAC project is a multi-chamber detector for Dark Matter search, aiming at measuring both track and ionization with a matrix of micromegas micro-TPC filled with He3 and CF4. Recent experimental results on the first measurements of the Helium quenching factor at low energy (1 keV recoil) are presented, together with the first simulation of the track reconstruction. Recontruction of track of alpha from Radon impurities is shown as a first proof of concept.Comment: 5 pages, Proc. of the fourth international symposium on large TPCs for low energy rare event detection, Paris, France, Dec. 2008. To appear in Journal of Physic

    MPGDs in Compton imaging with liquid-xenon

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    The interaction of radiation with liquid xenon, inducing both scintillation and ionization signals, is of particular interest for Compton-sequences reconstruction. We report on the development and recent results of a liquid-xenon time-projection chamber, dedicated to a novel nuclear imaging technique named "3 gamma imaging". In a first prototype, the scintillation is detected by a vacuum photomultiplier tube and the charges are collected with a MICROMEGAS structure; both are fully immersed in liquid xenon. In view of the final large-area detector, and with the aim of minimizing dead-zones, we are investigating a gaseous photomultiplier for recording the UV scintillation photons. The prototype concept is presented as well as preliminary results in liquid xenon. We also present soft x-rays test results of a gaseous photomultiplier prototype made of a double Thick Gaseous Electron Multiplier (THGEM) at normal temperature and pressure conditions.Comment: presented at MPGD09, CRETE, June 2009; to be published in JINST Proceedings, PDF, 10 pages, 11 figure

    Immunohistochemical characteristics of Renomedullary interstitial cell tumor: a study of 41 tumors with emphasis on differential diagnosis of mesenchymal neoplasms

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    Renomedullary interstitial cell tumors (RMICT) are almost always incidentally identified either at autopsy or resection of the kidney for other reasons. However, rare cases have been reported which are large, resulting in a clinical mass. The immunohistochemical phenotype of usual, incidental RMICT using modern soft tissue tumor markers in is largely unknown, however, providing little information to aid in classification of larger or atypical tumors. We retrieved 41 RMICTs from 36 patients, and studied pathologic characteristics including morphology, immunohistochemistry (S100, keratin AE1/AE3, smooth muscle actin, desmin, estrogen and progesterone receptors, calponin, CD34, CD35), and histochemical staining. Data collected included age, gender, tumor size, laterality, and indication for kidney examination. RMICTs (n = 41) were identified in 23 men and 13 women, with mean age 57 years (range 24–83), tumor sizes ranged from <1 to 13 mm (median 4 mm). Kidneys were resected for 32 tumors, 1 chronic pyelonephritis, 1 trauma, and 2 autopsies. All (41, 100%) had entrapped renal tubules, 5 (12%) of which included cystic or dilated tubules. Most (35, 85%) had collagenous fibers, all of which were negative for Congo red. RMICT demonstrates a largely negative immunohistochemical phenotype with weak to moderate labeling for smooth muscle actin and calponin that is substantially less than myofibroblastic lesions. Positive staining for estrogen and progesterone receptor is common (61%), which could overlap with mixed epithelial and stromal tumor and other entities; however, staining is typically weak. CD34 is usually negative, with occasional weak labeling, in contrast to solitary fibrous tumor
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