311 research outputs found
Reliability of Intra-Retinal Layer Thickness Estimates
Purpose Measurement of intra-retinal layer thickness using optical coherence
tomography (OCT) has become increasingly prominent in multiple sclerosis (MS)
research. Nevertheless, the approaches used for determining the mean layer
thicknesses vary greatly. Insufficient data exist on the reliability of
different thickness estimates, which is crucial for their application in
clinical studies. This study addresses this lack by evaluating the
repeatability of different thickness estimates. Methods Studies that used
intra-retinal layer segmentation of macular OCT scans in patients with MS were
retrieved from PubMed. To investigate the repeatability of previously applied
layer estimation approaches, we generated datasets of repeating measurements
of 15 healthy subjects and 13 multiple sclerosis patients using two OCT
devices (Cirrus HD-OCT and Spectralis SD-OCT). We calculated each thickness
estimate in each repeated session and analyzed repeatability using intra-class
correlation coefficients and coefficients of repeatability. Results We
identified 27 articles, eleven of them used the Spectralis SD-OCT, nine Cirrus
HD-OCT, two studies used both devices and two studies applied RTVue-100.
Topcon OCT-1000, Stratus OCT and a research device were used in one study
each. In the studies that used the Spectralis, ten different thickness
estimates were identified, while thickness estimates of the Cirrus OCT were
based on two different scan settings. In the simulation dataset, thickness
estimates averaging larger areas showed an excellent repeatability for all
retinal layers except the outer plexiform layer (OPL). Conclusions Given the
good reliability, the thickness estimate of the 6mm-diameter area around the
fovea should be favored when OCT is used in clinical research. Assessment of
the OPL was weak in general and needs further investigation before OPL
thickness can be used as a reliable parameter
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State-of-the-art stochastic data assimilation methods for high-dimensional non-Gaussian problems
This paper compares several commonly used state-of-the-art ensemble-based data assimilation methods in a coherent mathematical notation. The study encompasses different methods that are applicable to high-dimensional geophysical systems, like ocean and atmosphere, and provide an uncertainty estimate. Most variants of Ensemble Kalman Filters, Particle Filters and second-order exact methods are discussed, including Gaussian Mixture Filters, while methods that require an adjoint model or a tangent linear formulation of the model are excluded. The detailed description of all the methods in a mathematically coherent way provides both novices and experienced researchers with a unique overview and new insight in the workings and relative advantages of each method, theoretically and algorithmically, even leading to new filters. Furthermore, the practical implementation details of all ensemble and particle filter methods are discussed to show similarities and differences in the filters aiding the users in what to use when. Finally, pseudo-codes are provided for all of the methods presented in this paper
Does in vitro protocol predict the nutritional value of thermally treated cereals?
Several in vitro protocols were proposed to rapidly evaluate the nutritional value of cereal and food ingredients. These In vitro protocols are based on restricted parameters and may involve results differing to the reality once assessed in vivo. Moreover, information about some in vitro parameters is sometimes insufficiently described.
In the present study, a three steps in vitro digestion simulation developed by Tervila-Wilo et al. (1996) to mimic digestion in poultry digestive tract was assessed and compared with in vivo digestibility of corn grain harvest at two moisture contents and dried at three temperatures. In vitro digestion simulation showed that increasing drying temperature led to an increase in in vitro digestibility of dry matter (IVDMD) while in vivo digestibility of dry matter (DM) measured on force fed broilers chickens decreased in the same conditions.
To improve this in vitro digestion model, the effect of amylase activity of pancreatin, substrate concentration, corn flour particles reduction and agitation were investigated. Results showed that increasing amylase activity of pancreatin and decreasing substrate concentration improved DM digestibility through starch digestibility while corn flour particles reduction had little effect on its final DM digestibility. Rotational agitation greatly improved starch digestibility and therefore DM digestibility, even at low speed. This increase in DM digestibility reached 20% and was attributed to the better contact between substrate and enzymes and a reduction in solution viscosity under constant agitation. A good adjustment of these parameters would improve the ability of in vitro digestion simulation to accurately predict nutritional value of thermally treated cereals. They have to be taken into account on the implementation of in vitro digestion simulation aiming to predict in vivo performances of consumers.Maïsecvol:Optimisation des modalités de séchage du maïs grain cultivé en Wallonie au regard des performances zootechniques du poulet de chai
A geometric approach to time evolution operators of Lie quantum systems
Lie systems in Quantum Mechanics are studied from a geometric point of view.
In particular, we develop methods to obtain time evolution operators of
time-dependent Schrodinger equations of Lie type and we show how these methods
explain certain ad hoc methods used in previous papers in order to obtain exact
solutions. Finally, several instances of time-dependent quadratic Hamiltonian
are solved.Comment: Accepted for publication in the International Journal of Theoretical
Physic
Exercise training and high-sensitivity cardiac troponin T in patients with heart failure with reduced ejection fraction
Plasma cell disorders (PCDs) are identified in the clinical lab by detecting the monoclonal immunoglobulin (M-protein) which they produce. Traditionally, serum protein electrophoresis methods have been utilized to detect and isotype Mproteins. Increasing demands to detect low-level disease and new therapeutic monoclonal immunoglobulin treatments have stretched the electrophoretic methods to their analytical limits. Newer techniques based on mass spectrometry (MS) are emerging which have improved clinical and analytical performance. MS is gaining traction into clinical laboratories, and has replaced immunofixation electrophoresis (IFE) in routine practice at one institution. The International Myeloma Working Group (IMWG) Mass Spectrometry Committee reviewed the literature in order to summarize current data and to make recommendations regarding the role of mass spectrometric methods in diagnosing and monitoring patients with myeloma and related disorders. Current literature demonstrates that immune-enrichment of immunoglobulins coupled to intact light chain MALDI-TOF MS has clinical characteristics equivalent in performance to IFE with added benefits of detecting additional risk factors for PCDs, differentiating Mprotein from therapeutic antibodies, and is a suitable replacement for IFE for diagnosing and monitoring multiple myeloma and related PCDs. In this paper we discuss the IMWG recommendations for the use of MS in PCDs.publishedVersio
Desmopressin for bleeding in non-severe hemophilia A:Suboptimal use in a real-world setting
Background Desmopressin is an important treatment option in nonsevere hemophilia A because it has several benefits compared with factor (F) concentrates, including no inhibitor risk and much lower costs. Despite these advantages, data are limited on the real-world use of desmopressin in the treatment of bleeds. Objective To describe the clinical use of desmopressin in relation to other therapeutic modalities in the treatment of bleeding episodes in patients with nonsevere hemophilia A. Methods Patients with nonsevere hemophilia A aged 12-55 years were included from the DYNAMO cohort study. Data on the desmopressin test response and treated bleeding events in the period January 2009 to July 2020 were retrospectively collected from medical files. An adequate desmopressin test response was defined based on a peak FVIII level of >= 30 IU/dl. Results A total of 248 patients with a median age of 38 years (interquartile range 25-49) were included. An adequate desmopressin test response was documented in 25% and 73% of patients with moderate and mild hemophilia, respectively. In adequate responders, 51% of bleeds were exclusively treated with FVIII concentrates, 24% exclusively with desmopressin, 21% with a combination of both and 4% with other treatments. In 54% of bleeds treated with a single dose of factor concentrates, the expected FVIII level after desmopressin exceeded the level targeted. Conclusion Most bleeds in patients with an adequate response to desmopressin are treated with factor concentrates. These findings may indicate a suboptimal use of desmopressin and that barriers to the use of desmopressin should be explored.Thrombosis and Hemostasi
Circulating CD34 + /KDR + endothelial progenitor cells are reduced in chronic heart failure patients as a function of Type D personality
A B S T R A C T The aim of the present study was to assess whether EPC (endothelial progenitor cell) number/function might be an explanatory factor for the observed relationship between Type D personality (a joint tendency towards negative affectivity and social inhibition) and poor cardiovascular prognosis. We also assessed whether the effect of a single exercise bout on EPC number/function was affected by Type D personality. A total of 35 sedentary men with CHF (chronic heart failure; left ventricular ejection fraction 45 %) underwent CPET (cardiopulmonary exercise testing) and personality assessment with the 14-item Type D scale. CD34 + /KDR (kinase insert domain-containing receptor) + cells were quantified by flow cytometry before and immediately after CPET. Migration of early EPC towards VEGF (vascular endothelial growth factor) and SDF-1α (stromal-cell-derived factor-1α) was investigated. Type D (n = 10) and non-Type D (n = 25) patients were comparable with regards to demographics, disease severity and Framingham risk factor score. Circulating EPC numbers were reduced by 54 % in Type D compared with non-Type D patients (0.084 + − 0.055 and 0.183 + − 0.029 % of lymphocytes respectively; P = 0.006). Exercise led to a 60 % increase in EPC in Type D patients, whereas the EPC number remained unchanged in the non-Type D group (P = 0.049). Baseline migratory capacity was related to disease severity, but was not different between Type D and non-Type D patients. Exercise induced a highly significant enhancement of migratory capacity in both groups. In conclusion, reduced EPC numbers might explain the impaired cardiovascular outcome in Type D patients. The larger increase in circulating EPCs observed in these patients suggests that acute exercise elicits a more pronounced stimulus for endothelial repair
Delphi consensus recommendations on how to provide cardiovascular rehabilitation in the COVID-19 era
Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: [email protected] Delphi consensus by 28 experts from the European Association of Preventive Cardiology (EAPC) provides initial recommendations on how cardiovascular rehabilitation (CR) facilities should modulate their activities in view of the ongoing coronavirus disease 2019 (COVID-19) pandemic. A total number of 150 statements were selected and graded by Likert scale [from -5 (strongly disagree) to +5 (strongly agree)], starting from six open-ended questions on (i) referral criteria, (ii) optimal timing and setting, (iii) core components, (iv) structure-based metrics, (v) process-based metrics, and (vi) quality indicators. Consensus was reached on 58 (39%) statements, 48 'for' and 10 'against' respectively, mainly in the field of referral, core components, and structure of CR activities, in a comprehensive way suitable for managing cardiac COVID-19 patients. Panelists oriented consensus towards maintaining usual activities on traditional patient groups referred to CR, without significant downgrading of intervention in case of COVID-19 as a comorbidity. Moreover, it has been suggested to consider COVID-19 patients as a referral group to CR per se when the viral disease is complicated by acute cardiovascular (CV) events; in these patients, the potential development of COVID-related CV sequelae, as well as of pulmonary arterial hypertension, needs to be focused. This framework might be used to orient organization and operational of CR programmes during the COVID-19 crisis.info:eu-repo/semantics/publishedVersio
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