American Diagnostic Radiology Moves Offshore: Surfing the Internet Wave to Worldwide Access and Quality Perspectives: American Diagnostic Radiology Moves Offshore: Where Is the Internet Wave Taking This Field

International reading of medical imaging studies, or offshore teleradiology, has been a successful, though limited, practice benefiting patients and physicians for over a decade. Domestic and international market forces will continue to expand the demand for teleradiology as an important complement to United States based diagnostic radiology, though a full exodus of diagnostic reading to offshore sites is unlikely and inappropriate. Considerable obstacles remain to taking the teleradiology market to scale; however, barriers related to licensure, liability, quality assurance, and reimbursement will likely yield to market forces to be resolved in recognition of the significant benefits teleradiology offers to consumers and providers. As in other aspects of the economy, the world of medicine is becoming flat as the necessity of physical proximity is becoming less essential in the doctor-patient relationship. Telemedicine, which is the use of electronic information and communication technologies to diagnose and manage medical care from a distance, is realistic, successful, and even preferred in several instances. Telemedicine has existed for decades with telephone and fax, but with the Internet and the ability to view large amounts of audio and visual data at increasingly faster and cheaper rates, the practices of telemedicine is rapidly expanding

Extension of nano-confined DNA: quantitative comparison between experiment and theory

The extension of DNA confined to nanochannels has been studied intensively and in detail. Yet quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose we performed new experiments, measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic buffer strength. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths the agreement is less good. We discuss possible reasons. Our approach allows, in principle, to measure the Kuhn length and effective width of a single DNA molecule and more generally of semiflexible polymers in solution.Comment: Revised version, 6 pages, 2 figures, 1 table, supplementary materia

Reforming the Teaching and Learning of Foundational Mathematics Courses: An Investigation into the Status Quo of Teaching, Feedback Delivery, and Assessment in a First-Year Calculus Course

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Identification and rejection of scattered neutrons in AGATA

Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were measured in an AGATA experiment performed at INFN Laboratori Nazionali di Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors (12 36-fold segmented high-purity germanium crystals), placed at a distance of 50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment was to study the interaction of neutrons in the segmented high-purity germanium detectors of AGATA and to investigate the possibility to discriminate neutrons and gamma rays with the gamma-ray tracking technique. The BaF2 detectors were used for a time-of-flight measurement, which gave an independent discrimination of neutrons and gamma rays and which was used to optimise the gamma-ray tracking-based neutron rejection methods. It was found that standard gamma-ray tracking, without any additional neutron rejection features, eliminates effectively most of the interaction points due to recoiling Ge nuclei after elastic scattering of neutrons. Standard tracking rejects also a significant amount of the events due to inelastic scattering of neutrons in the germanium crystals. Further enhancements of the neutron rejection was obtained by setting conditions on the following quantities, which were evaluated for each event by the tracking algorithm: energy of the first and second interaction point, difference in the calculated incoming direction of the gamma ray, figure-of-merit value. The experimental results of tracking with neutron rejection agree rather well with Geant4 simulations

Brain lactate by magnetic resonance spectroscopy during fulminant hepatic failure in the dog

A noninvasive test is needed to assess the severity of encephalopathy during fulminant hepatic failure. This feasibility study was designed to compare a noninvasive test, brain lactate measurement by magnetic resonance spectroscopy, with intracranial pressure monitoring in a large animal model of fulminant hepatic failure. Five dogs received an intraventricular catheter for intracranial pressure measurement. Liver injury was induced by intravenous bolus of D-galactosamine. Brain lactate concentrations were determined by magnetic resonance spectroscopy for up to 48 hours after D- galactosamine administration (t = 0 hour). A dose of D-galactosamine exceeding 1.5 g/kg resulted in fulminant hepatic failure. Brain lactate levels increased to >10 mmol/L in the two dogs that developed severe intracranial hypertension of >50 mm Hg and sustained cerebral perfusion pressures of <40 mm Hg. Both dogs experienced brain death, 42 and 48 hours after the administration of D-galactosamine. Brain lactate concentrations determined by magnetic resonance spectroscopy were in agreement with brain tissue concentrations of lactate determined by high-performance liquid chromatography at necropsy. Plasma lactate concentrations were only mildly elevated (3.2 and 4.2 mmol/L) at the time of brain death. Elevated levels of brain lactate are associated with intracranial hypertension and poor neurological outcome during fulminant hepatic failure