4,285 research outputs found
Probing the Lewis acidity and catalytic activity of the metal-organic framework [Cu-3(btc)(2)] (BTC = benzene-1,3,5-tricarboxylate)
Worse Physical Disability Is Associated With the Expression of PD-1 on Inflammatory T-Cells in Multiple Sclerosis Patients With Older Appearing Brains
Background: Magnetic Resonance Imaging (MRI) analysis method “brain-age” paradigm could offer an intuitive prognostic metric (brain-predicted age difference: brain-PAD) for disability in Multiple Sclerosis (MS), reflecting structural brain health adjusted for aging. Equally, cellular senescence has been reported in MS using T-cell biomarker CD8+CD57+. Objective: Here we explored links between MRI-derived brain-age and blood-derived cellular senescence. We examined the value of combining brain-PAD with CD8+CD57+(ILT2+PD-1+) T-cells when predicting disability score in MS and considered whether age-related biological mechanisms drive disability. Methods: Brain-age analysis was applied to T1-weighted MRI images. Disability was assessed and peripheral blood was examined for CD8+CD57+ T-cell phenotypes. Linear regression models were used, adjusted for sex, age and normalized brain volume. Results: We included 179 mainly relapsing-remitting MS patients. A high brain-PAD was associated with high physical disability (mean brain-PAD = +6.54 [5.12–7.95]). CD8+CD57+(ILT2+PD-1+) T-cell frequency was neither associated with disability nor with brain-PAD. Physical disability was predicted by the interaction between brain-PAD and CD8+CD57+ILT2+PD-1+ T-cell frequency (AR2 = 0.196), yet without improvement compared to brain-PAD alone (AR2 = 0.206; AICc = 1.8). Conclusion: Higher frequency of CD8+CD57+ILT2+PD-1+ T-cells in the peripheral blood in patients with an older appearing brain was associated with worse disability scores, suggesting a role of these cells in the development of disability in MS patients with poorer brain health
Likelihood inference for exponential-trawl processes
Integer-valued trawl processes are a class of serially correlated, stationary
and infinitely divisible processes that Ole E. Barndorff-Nielsen has been
working on in recent years. In this Chapter, we provide the first analysis of
likelihood inference for trawl processes by focusing on the so-called
exponential-trawl process, which is also a continuous time hidden Markov
process with countable state space. The core ideas include prediction
decomposition, filtering and smoothing, complete-data analysis and EM
algorithm. These can be easily scaled up to adapt to more general trawl
processes but with increasing computation efforts.Comment: 29 pages, 6 figures, forthcoming in: "A Fascinating Journey through
Probability, Statistics and Applications: In Honour of Ole E.
Barndorff-Nielsen's 80th Birthday", Springer, New Yor
High incidence of diabetes after stroke in young adults and risk of recurrent vascular events: the FUTURE study
BACKGROUND: Diabetes diagnosed prior to stroke in young adults is strongly associated with recurrent vascular events. The relevance of impaired fasting glucose (IFG) and incidence of diabetes after young stroke is unknown. We investigated the long-term incidence of diabetes after young stroke and evaluated the association of diabetes and impaired fasting glucose with recurrent vascular events. METHODS: This study was part of the FUTURE study. All consecutive patients between January 1, 1980, and November 1, 2010 with TIA or ischemic stroke, aged 18-50, were recruited. A follow-up assessment was performed in survivors between November 1, 2009 and January 1, 2012 and included an evaluation for diabetes, fasting venous plasma glucose and recurrent vascular events. The association of diabetes and IFG with recurrent vascular events was assessed by logistic regression analysis, adjusted for age, sex and follow-up duration. RESULTS: 427 survivors without a medical history of diabetes were included in the present analysis (mean follow-up of 10.1 (SD 8.4) years; age 40.3 (SD 7.9) years). The incidence rate of diabetes was 7.9 per 1000 person-years and the prevalence of IFG was 21.1%. Patients with diabetes and IFG were more likely to have experienced any vascular event than those with normal fasting glucose values (OR 3.5 (95%CI 1.5-8.4) for diabetes and OR 2.5 (95%CI 1.3-4.8) for IFG). CONCLUSIONS: Diabetes or IFG in young stroke survivors is frequent and is associated with recurrent vascular events. Regular screening for IFG and diabetes in this population, yields potential for secondary prevention
Automating Deductive Verification for Weak-Memory Programs
Writing correct programs for weak memory models such as the C11 memory model
is challenging because of the weak consistency guarantees these models provide.
The first program logics for the verification of such programs have recently
been proposed, but their usage has been limited thus far to manual proofs.
Automating proofs in these logics via first-order solvers is non-trivial, due
to reasoning features such as higher-order assertions, modalities and rich
permission resources. In this paper, we provide the first implementation of a
weak memory program logic using existing deductive verification tools. We
tackle three recent program logics: Relaxed Separation Logic and two forms of
Fenced Separation Logic, and show how these can be encoded using the Viper
verification infrastructure. In doing so, we illustrate several novel encoding
techniques which could be employed for other logics. Our work is implemented,
and has been evaluated on examples from existing papers as well as the Facebook
open-source Folly library.Comment: Extended version of TACAS 2018 publicatio
The Effect of wake Turbulence Intensity on Transition in a Compressor Cascade
Direct numerical simulations of separating flow along a section at midspan of a low-pressure V103 compressor cascade with periodically incoming wakes were performed. By varying the strength of the wake, its influence on both boundary layer separation and bypass transition were examined. Due to the presence of small-scale three-dimensional fluctuations in the wakes, the flow along the pressure surface undergoes bypass transition. Only in the weak-wake case, the boundary layer reaches a nearly-separated state between impinging wakes. In all simulations, the flow along the suction surface was found to separate. In the simulation with the strong wakes, separation is intermittently suppressed as the periodically passing wakes managed to trigger turbulent spots upstream of the location of separation. As these turbulent spots convect downstream, they locally suppress separation. © 2014 Springer Science+Business Media Dordrecht
Clear lens phacoemulsification in the anterior lenticonus due to Alport Syndrome: two case reports
<p>Abstract</p> <p>Introduction</p> <p>Alport Syndrome has a prevalence of 1 case per 5,000 people and 85% of patients have the X-linked form, where affected males develop renal failure and usually have high-tone sensorineural deafness by age 20. The main abnormality is deficient synthesis of type IV collagen, the main component of basement membranes. Common ocular abnormalities of this syndrome consist of dot-and-fleck retinopathy, posterior polymorphous corneal dystrophy, and anterior lenticonus, but other ocular defects such as cataracts, posterior lenticonus, and retinal detachments have also been reported.</p> <p>Case presentation</p> <p>We report two cases of anterior lenticonus due to Alport Syndrome and describe clear lens phacoemulsification and foldable intraocular lens implantation as an effective and safe refractive procedure in the four eyes of these two patients.</p> <p>Conclusion</p> <p>All four eyes of the two patients were in good condition after surgery and achieved satisfactory optical and visual results and had no remarkable complications at six-months follow-up. Clear lens phacoemulsification with foldable intraocular lens implantation can be used as an efficient and safe procedure for vision disorders in these patients.</p
Medium/Long wavelength sensitive opsin diversity in Pitheciidae
New World primates feature a complex colour vision system. Most species have polymorphic colour vision where males have a dichromatic colour perception and females can be either ichromatic or trichromatic. The adaptive value of high allelic diversity of opsins, a light sensitive protein, found in primates’ eyes remains unknown. Studies revealing the allelic diversity are important as they shed
light on our understanding of the adaptive value of differences in the colouration of species and their ecologies. Here we investigate the allelic types found in Pitheciidae, an understudied New World
primate family, revealing the diversity of medium/long wavelength sensitive opsins both in cryptic and conspicuous species of this primate family. We found five alleles in Cacajao, six in Callicebinae (i.e. Plecturocebus, Cheracebus, and Callicebus), four in Chiropotes, and three in Pithecia, some of them reported for the first time. Both cryptic and conspicuous species in this group presented high allelic diversity
Real-time imputation of missing predictor values in clinical practice
Use of prediction models is widely recommended by clinical guidelines, but
usually requires complete information on all predictors that is not always
available in daily practice. We describe two methods for real-time handling of
missing predictor values when using prediction models in practice. We compare
the widely used method of mean imputation (M-imp) to a method that personalizes
the imputations by taking advantage of the observed patient characteristics.
These characteristics may include both prediction model variables and other
characteristics (auxiliary variables). The method was implemented using
imputation from a joint multivariate normal model of the patient
characteristics (joint modeling imputation; JMI). Data from two different
cardiovascular cohorts with cardiovascular predictors and outcome were used to
evaluate the real-time imputation methods. We quantified the prediction model's
overall performance (mean squared error (MSE) of linear predictor),
discrimination (c-index), calibration (intercept and slope) and net benefit
(decision curve analysis). When compared with mean imputation, JMI
substantially improved the MSE (0.10 vs. 0.13), c-index (0.70 vs 0.68) and
calibration (calibration-in-the-large: 0.04 vs. 0.06; calibration slope: 1.01
vs. 0.92), especially when incorporating auxiliary variables. When the
imputation method was based on an external cohort, calibration deteriorated,
but discrimination remained similar. We recommend JMI with auxiliary variables
for real-time imputation of missing values, and to update imputation models
when implementing them in new settings or (sub)populations.Comment: 17 pages, 6 figures, to be published in European Heart Journal -
Digital Health, accepted for MEMTAB 2020 conferenc
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