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Now showing items 1 - 16 of 200

  • Tl2LaCl5: Ce, high performance scintillator for gamma-ray detectors

    Hawrami, R.   Ariesanti, E.   Wei, H.   Finkelstein, J.   Glodo, J.   Shah, K. S.  

    This paper reports on a new Ce-doped Tl-based scintillator, Tl2LaCl5 (TLC), for gamma-ray detection. 10 mm diameter crystals have been successfully grown using the vertical Bridgman method. The emission peak of TLC is detected at 383 nm under X-ray excitation. The light yield of TLC is 76,000 ph/MeV. The samples show excellent energy resolution of 3.4% (FWHM) at 662 keV. The non-proportionality is less than 1%, from 32 keV to 1275 keV. The major scintillation decay time is 36 ns. (C) 2017 Elsevier B. V. All rights reserved.
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  • Intrinsic scintillators: TlMgCl3 and TlCaI3

    Hawrami, R.   Ariesanti, E.   Wei, H.   Finkelstein, J.   Glodo, J.   Shah, K. S.  

    Two intrinsic scintillators TlMgCl3 and TlCaI3 with excellent energy resolution and fast scintillation decay are presented. Crack-free transparent crystals were successfully grown by the Bridgman method. The scintillation light yields of TlMgCl3 and TlCaI3 are approximately 30,600 ph/MeV and 42,200 ph/MeV, respectively. Their energy resolutions at 662 keV are 3.7% for TlMgCl3 and 6.2% for TlCaI3. The scintillation decay times of TlMgCl3 are 46 ns, 166 ns, and 449 ns. The scintillation decay times of TlCaI3 are 62 ns, 200 ns, and 1.44 mu s. Under X-ray irradiation, the emission of TlMgCl3 is between 300 nm and 540 nm with the peak at 409 nm. TlCaI3 has a broad emission band between 300 nm and 750 nm. Due to their excellent scintillation properties, these two scintillators can be developed for gamma-ray detection. Additionally, TlMgCl3 is non-hygroscopic. (C) 2017 Elsevier B.V. All rights reserved.
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  • TI2LiYCI6: Large Diameter, High Performing Dual Mode Scintillator

    Hawrami, R.   Ariesanti, E.   Wei, H.   Finkelstein, J.   Glodo, J.   Shah, K.  

    Tl2LiYCl6:Ce (TLYC) is a recently discovered dual mode gamma-ray and neutron scintillator. So far small crystals of this composition have been studied, but for, practical applications with affordable price, large-scale crystals are required. In this work, we present successful efforts to grow crack-free single crystals with sizes up to emptyset1" X 5.5". A variety of experimental techniques were employed to investigate the scintillation properties. A emptyset1" X 1.2" TLYC cylinder has a light yield of 25,000 ph/MeV, and its energy resolution is better than 4% at 662 keV. The gamma equivalent energy (GEE) produced by thermal neutron is 1.89 MeVee, along with a neutron induced light yield of 47,000 ph/n. Pulse shape discrimination (PSD) between gamma-rays and neutrons has been successfully shown with a current Figure-of-Merit (FOM) of 2.4. This article explores the crystal growth, scintillation properties, and potential applications of TLYC.
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  • Cs2LiLa(Br, Cl)(6) Crystals for Nuclear Security Applications

    Hawrami, R.   Pandian, L. Soundara   Ariesanti, E.   Glodo, J.   Finkelstein, J.   Tower, J.   Shah, K.  

    Properties of dual-mode scintillation detectors based on CLLBC crystals are reported. Energy resolution and light yield are measured at 2.9% (FWHM) at 662 keV and 45 000 photons/MeV, respectively, for a 1-in-diameter and 1-in-long crystal. With less than 2% variation in light yield as a function of energy, CLLBC has better proportionality than LaBr3 and NaI:Tl. Neutron peak resulting from reactions with neutrons emitted by Cf-252 (moderated) is measured at a gamma energy equivalent of 3.1 MeVee (electron energy equivalent), making pulse height discrimination between gamma-rays and neutrons easy. The material is also of effective pulse shape discrimination. The figure-of-merit for discrimination of gamma rays and thermal neutrons in CLLBC can be as high as 3.2, which is comparable to that of CLYC.
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  • Gene delivery to the spinal cord using MRI-guided focused ultrasound

    Weber-Adrian, D.   Thevenot, E.   O'Reilly, M. A.   Oakden, W.   Akens, M. K.   Ellens, N.   Markham-Coultes, K.   Burgess, A.   Finkelstein, J.   Yee, A. J. M.   Whyne, C. M.   Foust, K. D.   Kaspar, B. K.   Stanisz, G. J.   Chopra, R.   Hynynen, K.   Aubert, I.  

    Non-invasive gene delivery across the blood-spinal cord barrier (BSCB) remains a challenge for treatment of spinal cord injury and disease. Here, we demonstrate the use of magnetic resonance image-guided focused ultrasound (MRIgFUS) to mediate nonsurgical gene delivery to the spinal cord using self-complementary adeno-associated virus serotype 9 (scAAV9). scAAV9 encoding green fluorescent protein (GFP) was injected intravenously in rats at three dosages: 4 x 10(8), 2 x 10(9) and 7 x 10(9) vector genomes per gram (VG g(-1)). MRIgFUS allowed for transient, targeted permeabilization of the BSCB through the interaction of focused ultrasound (FUS) with systemically injected Definity lipid-shelled microbubbles. Viral delivery at 2 x 10(9) and 7 x 10(9) VG g(-1) leads to robust GFP expression in FUS-targeted regions of the spinal cord. At a dose of 2 x 10(9) VG g(-1), GFP expression was found in 36% of oligodendrocytes, and in 87% of neurons in FUS-treated areas. FUS applications to the spinal cord could address a long-term goal of gene therapy: delivering vectors from the circulation to diseased areas in a non-invasive manner.
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  • 79-YEAR OLD MAN WITH PARKINSONISM AND ACUTE SPINAL CORD COMPRESSION

    Diamandis, P.   Amato, D.   Finkelstein, J.   Keith, J.  

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  • Hypertension Telemanagement in Blacks

    Finkelstein, J.   Cha, E.  

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  • CONSUMER HEALTH INFORMATION TECHNOLOGY IN THE PREVENTION OF SUBSTANCE ABUSE:A SCOPING REVIEW

    Pradhan, A.   Park, L.   Shaya, F. T.   Finkelstein, J.  

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  • Evaluation of home telemanagement in adult asthma patients

    Finkelstein, J.   Joshi, A.   Amelung, P.  

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  • Pure-state informationally complete and “really” complete measurements

    Finkelstein, J.  

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  • Comment on “How macroscopic properties dictate microscopic probabilities”

    Finkelstein, J.  

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  • An analysis of ideal and actual time to surgery after traumatic spinal cord injury in Canada

    Glennie, R. A.   Bailey, C. S.   Tsai, E. C.   Noonan, V. K.   Rivers, C. S.   Fourney, D. R.   Ahn, H.   Kwon, B. K.   Paquet, J.   Drew, B.   Fehlings, M. G.   Attabib, N.   Christie, S. D.   Finkelstein, J.   Hurlbert, R. J.   Parent, S.   Dvorak, M. F.  

    Study design: Retrospective analysis of a prospective registry and surgeon survey. Objectives: To identify surgeon opinion on ideal practice regarding the timing of decompression/stabilization for spinal cord injury and actual practice. Discrepancies in surgical timing and barriers to ideal timing of surgery were explored. Setting: Canada. Methods: Patients from the Rick Hansen Spinal Cord Registry (RHSCIR, 2004-2014) were reviewed to determine actual timing of surgical management. Following data collection, a survey was distributed to Canadian surgeons, asking for perceived to be the optimal and actual timings of surgery. Discrepancies between actual data and surgeon survey responses were then compared using chi(2) tests and logistic regression. Results: The majority of injury patterns identified in the registry were treated operatively. ASIA Impairment Scale (AIS) C/D injuries were treated surgically less frequently in the RHSCIR data and surgeon survey (odds ratio (OR)=3D 0.39 and 0.26). Significant disparities between what surgeons identified as ideal, actual current practice and RHSCIR data were demonstrated. A great majority of surgeons (93.0%) believed surgery under 24 h was ideal for cervical AIS A/B injuries and 91.0% for thoracic AIS A/B/C/D injuries. Definitive surgical management within 24 h was actually accomplished in 39.0% of cervical and 45.0% of thoracic cases. Conclusion: Ideal surgical timing for traumatic spinal cord injury (tSCI) within 24 h of injury was identified, but not accomplished. Discrepancies between the opinions on the optimal and actual timing of surgery in tSCI patients suggest the need for strategies for knowledge translation and reduction of administrative barriers to early surgery.
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  • Clinical features of conjoined lumbosacral nerve roots versus lumbar intervertebral disc herniations

    Lotan, R.   Al-Rashdi, A.   Yee, A.   Finkelstein, J.  

    Unidentified nerve root anomalies, conjoined nerve root (CNR) being the most common, may account for some failed spinal surgical procedures as well as intraoperative neural injury. Previous studies have failed to clinically discern CNR from herniated discs and found their surgical outcomes as being inferior. A comparative study of CNR and disc herniations was undertaken. Between 2002 and 2008, 16 consecutive patients were diagnosed intraoperatively with CNR. These patients were matched 1:2 with 32 patients diagnosed with intervertebral disc herniations. Matching was done according to age (within 5 years), gender and level of pathology. Surgery for patients with CNR or disc herniations consisted of routine microsurgical techniques with microdiscectomy, hemilaminotomy, hemilaminectomy and foraminotomy as indicated. Outcomes were measured using the Oswestry Disability Index and the Short Form-36 Questionnaire. Clinical presentation, imaging studies and surgical outcomes were compared between the groups. Conjoined nerve root's incidence in this study was 5.8% of microdiscectomies performed. The S1 nerve root was mainly involved (69%), followed by L5 (31%). Patients with CNR tended to present with nerve root claudication (44%) compared to the radiculopathy accompanying disc herniations (75%). Neurologic deficit was less prevalent among patients with CNR. Nerve root tension tests were not helpful in distinguishing between the etiologies. Radiologist's suspicion threshold for nerve root anomalies was low (0%) and no coronal reconstructions were obtained. The surgeon's clinical suspicion accurately predicted 40% of the CNRs. Surgical outcomes did not differ between the cohorts regarding the rate of postoperative improvement, but CNR patients showed a trend toward having mildly worse long-term outcomes. Suspecting CNRs preoperatively is beneficial for appropriate treatment and avoiding the risk of intraoperative neural injury. With nerve root claudication and imaging suggestive of a "disc herniation", the surgeon should be alert to the differential diagnosis of a CNR. Treatment is directed at obtaining adequate decompression by laminectomy and foraminotomy to relieve the lateral recess stenosis. Outcomes can be expected to be similar to routine disc herniations.
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  • FDA User Fee Law Poised for Passage in Congress but Not Without Stirring Up Controversy

    Finkelstein, J.  

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  • Ambiguities of arrival-time distributions in quantum theory

    Finkelstein, J.  

    We consider the definition that might be given, in quantum theory, to the time at which a particle arrives at a given place. We discuss an ambiguity that arises in three, but not in one, spatial dimensions. We first express this ambiguity within the ontology of Bohmian quantum theory, but we also show that it can be expressed independently of that ontology
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  • Comment on “Consistency, amplitudes, and probabilities in quantum theory”

    Finkelstein, J.  

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