404 research outputs found
Uncertain Flow Visualization using LIC
In this paper we look at the Line Integral Convolution method for flow visualization and ways in which this can be
applied to the visualization of two dimensional, steady flow fields in the presence of uncertainty. To achieve this,
we start by studying the method and reviewing the history of modifications other authors have made to it in order
to improve its efficiency or capabilities, and using these as a base for the visualization of uncertain flow fields.
Finally, we apply our methodology to a case study from the field of oceanography
Association of CSF sTREM2, a marker of microglia activation, with cholinergic basal forebrain volume in major depressive disorder
BACKGROUND: Inflammatory mechanisms are believed to contribute to the manifestation of major depressive disorder (MDD). Central cholinergic activity may moderate this effect. Here, we tested if volume of the cholinergic basal forebrain is associated with cerebrospinal fluid (CSF) levels of sTREM2 as a marker of microglial activation in people with late life MDD. METHODS: Basal forebrain volume was determined from structural MRI scans and levels of CSF sTREM2 with immunoassay in 29 people with late-life MDD and 20 healthy older controls at baseline and 3 years follow-up. Associations were determined using Bayesian analysis of covariance. RESULTS: We found moderate level of evidence for an association of lower CSF levels of sTREM2 at 3 years follow up with MDD (Bayes factor in favor of an effect = 7.9). This level of evidence prevailed when controlling for overall antidepressant treatment and CSF levels of markers of AD pathology, i.e., Aβ42/Aβ40, ptau181 and total tau. Evidence was in favor of absence of an effect for baseline levels of CSF sTREM2 in MDD cases and for baseline and follow up data in controls. LIMITATIONS: The sample size of repeated CSF examinations was relatively small. Therefore, we used Bayesian sequential analysis to assess if effects were affected by sample size. Still, the number of cases was too small to stratify effects for different antidepressive treatments. CONCLUSIONS: Our data agree with the assumption that central cholinergic system integrity may contribute to regulation of microglia activity in late-life MDD
State-dependent alterations in cerebrospinal fluid A42 levels in cognitively intact elderly with late-life major depression
Depression has been linked to Alzheimerâs disease as either an increased risk factor for its development or as a prodromal symptom. The neurobiological basis for such an association, however, remains poorly understood. Numerous studies have examined whether changes in amyloid beta (A[beta]) metabolism, which are implicated in the pathogenesis of Alzheimerâs disease, are also found in depression. In this paper, we investigated the relationship between depressive symptoms and cerebrospinal fluid (CSF) A[beta] indices in otherwise healthy, cognitively normal elderly with late-life major depression (LLMD) and controls using a longitudinal approach, which is a novel contribution toward the literature. Significantly lower levels of CSF A[beta]42 were observed in the LLMD group at baseline and were associated with more severe depressive symptoms. During longitudinal follow-up, the depressed group remained cognitively unchanged, but was significantly less depressed than at baseline. A greater improvement in depressive symptoms was associated with increases in CSF A[beta]42 levels in both groups. Increases in CSF A[beta]42 and A[beta]40 were also associated with increased CSF total-tau levels. Our results suggest that LLMD may be associated with state-dependent effects of CSF A[beta]42 levels. Future studies should determine whether the association reflects state-dependent changes in neuronal activity and/or brain amyloid burden in depression
Acute myelogenous leukemia switch lineage upon relapse to acute lymphoblastic leukemia: a case report
Acute leukemia, the most common form of cancer in children, accounts for approximately 30% of all childhood malignancies, with acute lymphoblastic leukemia being five times more frequent than acute myeloid leukemia. Lineage switch is the term that has been used to describe the phenomenon of acute leukemias that meet the standard French-American-British system criteria for a particular lineage (either lymphoid or myeloid) upon initial diagnosis, but meet the criteria for the opposite lineage at relapse. Many reports have documented conversions of acute lymphoblastic leukemia to acute myeloid leukemia
Comparison of two protective lung ventilatory regimes on oxygenation during one-lung ventilation: a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>The efficacy of protective ventilation in acute lung injury has validated its use in the operating room for patients undergoing thoracic surgery with one-lung ventilation (OLV). The purpose of this study was to investigate the effects of two different modes of ventilation using low tidal volumes: pressure controlled ventilation (PCV) vs. volume controlled ventilation (VCV) on oxygenation and airway pressures during OLV.</p> <p>Methods</p> <p>We studied 41 patients scheduled for thoracoscopy surgery. After initial two-lung ventilation with VCV patients were randomly assigned to one of two groups. In one group OLV was started with VCV (tidal volume 6 mL/kg, PEEP 5) and after 30 minutes ventilation was switched to PCV (inspiratory pressure to provide a tidal volume of 6 mL/kg, PEEP 5) for the same time period. In the second group, ventilation modes were performed in reverse order. Airway pressures and blood gases were obtained at the end of each ventilatory mode.</p> <p>Results</p> <p>PaO<sub>2</sub>, PaCO<sub>2 </sub>and alveolar-arterial oxygen difference did not differ between PCV and VCV. Peak airway pressure was significantly lower in PCV compared with VCV (19.9 Âą 3.8 cmH<sub>2</sub>O vs 23.1 Âą 4.3 cmH<sub>2</sub>O; p < 0.001) without any significant differences in mean and plateau pressures.</p> <p>Conclusions</p> <p>In patients with good preoperative pulmonary function undergoing thoracoscopy surgery, the use of a protective lung ventilation strategy with VCV or PCV does not affect the oxygenation. PCV was associated with lower peak airway pressures.</p
Clinical variability in spinal muscular atrophy type III
Objective:
We report natural history data in a large cohort of 199 patients with spinal muscular atrophy (SMA) type III assessed using the Hammersmith Functional Motor Scale Expanded (HFMSE). The aim of the study was to establish the annual rate and possible patterns of progression according to a number of variables, such as age of onset, age at assessment, SMN2 copy number, and functional status.
Methods:
HFMSE longitudinal changes were assessed using piecewise linear mixedâeffects models. The dependency in the data due to repeated measures was accounted for by a random intercept per individual and an unstructured covariance R matrix was used as correlation structure. An additional descriptive analysis was performed for 123 patients, for a total of 375 12âmonth assessments.
Results:
A break point at age 7âyears was set for the whole cohort and for SMA IIIA and IIIB. Age, SMA type, and ambulatory status were significantly associated with changes in mean HFMSE score, whereas gender and SMN2 copy number were not. The increase in response before the break point of age 7âyears is significant only for SMA IIIA (β = 1.79, p <â0.0001). After the break point, the change in the rate of HFMSE score significantly decrease for both SMA IIIA (β = â1.15, p <â0.0001) and IIIB (β = â0.69, p =â0.002).
Interpretation:
Our findings contribute to the understanding of the natural history of SMA type III and will be helpful in the interpretation of the realâworld data of patients treated with commercially available drugs. ANN NEUROL 2020;88:1109â111
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
The azimuthal anisotropy of charged particles in PbPb collisions at
nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS
detector at the LHC over an extended transverse momentum (pt) range up to
approximately 60 GeV. The data cover both the low-pt region associated with
hydrodynamic flow phenomena and the high-pt region where the anisotropies may
reflect the path-length dependence of parton energy loss in the created medium.
The anisotropy parameter (v2) of the particles is extracted by correlating
charged tracks with respect to the event-plane reconstructed by using the
energy deposited in forward-angle calorimeters. For the six bins of collision
centrality studied, spanning the range of 0-60% most-central events, the
observed v2 values are found to first increase with pt, reaching a maximum
around pt = 3 GeV, and then to gradually decrease to almost zero, with the
decline persisting up to at least pt = 40 GeV over the full centrality range
measured.Comment: Replaced with published version. Added journal reference and DO
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