1,507 research outputs found
Design and Implementation of a Practical Business Oriented Undergraduate Data Communications Curriculum
The content and orientation of undergraduate computer information systems curricula have historically been designed and implemented in response to the dominant systems architecture of the time and the associated skills required by professionals in support of that systems architecture. As the information systems architecture paradigm has shifted in recent years from a centralized mainframe/terminal focus to a distributed client/server orientation, the role of data communications and networking has shifted from an ancillary electrical engineering oriented specialty to a computer information systems oriented area of study at the very heart of distributed computing
Endogenous Progenitors Remyelinate Demyelinated Axons in the Adult CNS
AbstractRemyelination occurs in demyelinated CNS regions in diseases such as multiple sclerosis. Identification of the cell type(s) responsible for this remyelination, however, has been elusive. Here, we examine one potential source of remyelinating oligodendrocytes—immature, cycling cells endogenous to adult white matter—and demonstrate that this population responds to demyelination by differentiating into myelinating oligodendrocytes. Dividing cells in subcortical white matter of adult rats were labeled by stereotactic injection of a replication-deficient lacZ-encoding retrovirus (BAG). Following a focal demyelination induced with lysolecithin, many of the BAG-labeled cells differentiated into myelinating oligodendrocytes engaging in repair of the lesion. Identification of endogenous cells capable of remyelination provides a target for the study of CNS repair processes in demyelinating diseases
‘Pontinization’ of the medulla: two clinical case studies
The authors report 2 clinical cases of human brainstems where there is blurring of the boundary between the medulla and pons, leading to "pontinization" of the medull
Observation of a subgap density of states in superconductor-normal metal bilayers in the Cooper limit
We present transport and tunneling measurements of Pb-Ag bilayers with
thicknesses, and , that are much less than the superconducting
coherence length. The transition temperature, , and energy gap, ,
in the tunneling Density of States (DOS) decrease exponentially with
at fixed . Simultaneously, a DOS that increases linearly from the Fermi
energy grows and fills nearly 40% of the gap as is 1/10 of of bulk
Pb. This behavior suggests that a growing fraction of quasiparticles decouple
from the superconductor as goes to 0. The linear dependence is consistent
with the quasiparticles becoming trapped on integrable trajectories in the
metal layer.Comment: 5 pages and 4 figures. This version is just the same as the old
version except that we try to cut the unnecessary white space in the figures
and make the whole paper look more compac
Some Radiative Corrections to Neutrino Scattering: I Neutral Currents
With the advent of high precision neutrino scattering experiments comes the
need for improved radiative corrections. We present a phenomenological analysis
of some contributions to the production of photons in neutrino neutral current
scattering that are relevant to experiments subsuming the 1% level.Comment: 17 Pages, 7 .pdf Figure
Substellar Companions to Main Sequence Stars: No Brown Dwarf Desert at Wide Separations
We use three field L and T dwarfs which were discovered to be wide companions
to known stars by the Two Micron All-Sky Survey (2MASS) to derive a preliminary
brown dwarf companion frequency. Observed L and T dwarfs indicate that brown
dwarfs are not unusually rare as wide (Delta >1000 A.U.) systems to F-M0
main-sequence stars (M>0.5M_sun, M_V<9.5), even though they are rare at close
separation (Delta <3 A.U.), the ``brown dwarf desert.'' Stellar companions in
these separation ranges are equally frequent, but brown dwarfs are >~ 10 times
as frequent for wide than close separations. A brown dwarf wide-companion
frequency as low as the 0.5% seen in the brown dwarf desert is ruled out by
currently-available observations.Comment: ApJL, in pres
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Pathological Correlates of Extrapyramidal Signs in Alzheimer's Disease
Extrapyramidal signs frequently accompany Alzheimer's disease (AD), but the pathological substrate remains unknown. Clinical and postmortem information from patients with AD, Parkinson's disease, or progressive supranuclear palsy and control subjects seen at a large tertiary medical center between 1989 and 1994 was examined. AD patients who had taken neuroleptics and AD brains that also contained Lewy bodies were excluded. Sections of basal ganglia, subthalamic nucleus, and substantia nigra were examined for neurofibrillary tangles and neuropil threads and the nigra for neuronal numbers. The presence of extrapyramidal signs was determined using the Unified Parkinson's Disease Rating Scale. Patients with AD (with or without extrapyramidal signs) did not show neuronal loss in the nigra compared to control subjects, while both Parkinson's disease and progressive supranuclear palsy brains showed marked depletion. The number of neurofibrillary tangles and neuropil threads was increased in AD (with or without extrapyramidal signs) nigra compared to control tissue, and also in progressive supranuclear palsy nigra, but not Parkinson's disease nigra. The numbers of nigral neurofibrillary tangles and neuropil threads were positively related to extrapyramidal signs in AD. There were no correlations between tangles and threads in the basal ganglia or subthalamic nucleus and extrapyramidal signs in AD. Thus, extrapyramidal signs in AD correlate best with tangle pathology in the nigra and do not require the concomitant presence of Lewy bodies
A molecular biology and phase II trial of lapatinib in children with refractory CNS malignancies: a pediatric brain tumor consortium study.
High expression of ERBB2 has been reported in medulloblastoma and ependymoma; EGFR is amplified and over-expressed in brainstem glioma suggesting these proteins as potential therapeutic targets. We conducted a molecular biology (MB) and phase II study to estimate inhibition of tumor ERBB signaling and sustained responses by lapatinib in children with recurrent CNS malignancies. In the MB study, patients with recurrent medulloblastoma, ependymoma, and high-grade glioma (HGG) undergoing resection were stratified and randomized to pre-resection treatment with lapatinib 900 mg/m(2) dose bid for 7-14 days or no treatment. Western blot analysis of ERBB expression and pathway activity in fresh tumor obtained at surgery estimated ERBB receptor signaling inhibition in vivo. Drug concentration was simultaneously assessed in tumor and plasma. In the phase II study, patients, stratified by histology, received lapatinib continuously, to assess sustained response. Eight patients, on the MB trial (four medulloblastomas, four ependymomas), received a median of two courses (range 1-6+). No intratumoral target inhibition by lapatinib was noted in any patient. Tumor-to-plasma ratios of lapatinib were 10-20 %. In the 34 patients (14 MB, 10 HGG, 10 ependymoma) in the phase II study, lapatinib was well-tolerated at 900 mg/m(2) dose bid. The median number of courses in the phase II trial was two (range 1-12). Seven patients (three medulloblastoma, four ependymoma) remained on therapy for at least four courses range (4-26). Lapatinib was well-tolerated in children with recurrent or CNS malignancies, but did not inhibit target in tumor and had little single agent activity.Fil: Fouladi, Maryam. St. Jude Children’s Research Hospital; Estados UnidosFil: Stewart, Clinton F.. St. Jude Children’s Research Hospital; Estados UnidosFil: Blaney, Susan M.. Baylor College of Medicine. Texas Children’s Cancer Center; Estados UnidosFil: Onar Thomas, Arzu. St. Jude Children’s Research Hospital; Estados UnidosFil: Schaiquevich, Paula Susana. St. Jude Children’s Research Hospital; Estados Unidos. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Packer, Roger J.. Children’s National Medical Center; Estados UnidosFil: Goldman, Stewart. Anne and Robert H. Lurie Children’s Hospital of Chicago; Estados UnidosFil: Geyer, J. Rusell. Children’s Hospital and Regional Medical Center; Estados UnidosFil: Gajjar, Amar. St. Jude Children’s Research Hospital; Estados UnidosFil: Kun, Larry E.. St. Jude Children’s Research Hospital; Estados UnidosFil: Boyett, James M.. St. Jude Children’s Research Hospital; Estados UnidosFil: Gilbertson, Richard J.. St. Jude Children’s Research Hospital; Estados Unido
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