Introduction: Application of the chronic thromboembolic pulmonary hypertension (CTEPH) rule out criteria (manual electrocardiogram [ECG] reading and N-terminal pro-brain natriuretic peptide ... Show moreIntroduction: Application of the chronic thromboembolic pulmonary hypertension (CTEPH) rule out criteria (manual electrocardiogram [ECG] reading and N-terminal pro-brain natriuretic peptide [NTproBNP] test) can rule out CTEPH in pulmonary embolism (PE) patients with persistent dyspnea (InShape II algorithm). Increased pulmonary pressure may also be identified using automated ECG-derived ventricular gradient optimized for right ventricular pressure overload (VG-RVPO). Method: A predefined analysis of the InShape II study was performed. The diagnostic performance of the VG-RVPO for the detection of CTEPH and the incremental diagnostic value of the VG-RVPO as new rule-out criteria in the InShape II algorithm were evaluated. Results: 60 patients were included; 5 (8.3%) were ultimately diagnosed with CTEPH. The mean baseline VG-RVPO (at time of PE diagnosis) was -18.12 mV.ms for CTEPH patients and - 21.57 mV.ms for non-CTEPH patients (mean difference 3.46 mV.ms [95%CI -29.03 to 35.94]). The VG-RVPO (after 3-6 months follow-up) normalized in patients with and without CTEPH, without a clear between-group difference (mean Delta VG-RVPO of -8.68 and - 8.42 mV.ms respectively; mean difference of -0.25 mV.ms, [95%CI -12.94 to 12.44]). The overall predictive accuracy of baseline VG-RVPO, follow-up RVPO and Delta VG-RVPO for CTEPH was moderate to poor (ROC AUC 0.611, 0.514 and 0.539, respectively). Up to 76% of the required echocardiograms could have been avoided with VG-RVPO criteria replacing the InShape II rule-out criteria, however at cost of missing up to 80% of the CTEPH diagnoses. Conclusion: We could not demonstrate (additional) diagnostic value of VG-RVPO as standalone test or as on top of the InShape II algorithm. Show less
An algorithm is discussed to compute the exponential representation of principal units in a finite extension field F of the p-adic rationals. Also is discussed the computation of roots of unity... Show moreAn algorithm is discussed to compute the exponential representation of principal units in a finite extension field F of the p-adic rationals. Also is discussed the computation of roots of unity contained in F and a special kind of principal unit, which is called a distinguished unit. The properties of norm residue symbols are given and also an algorithm to compute the norm residue symbol. Moreover a strongly distinguished unit is defined and an algorithm is given to compute such a unit. All the algorithms are polynomial time algorithms. Show less
Salverda, H.H.; Oldenburger, N.J.; Rijken, M.; Pauws, S.C.; Dargaville, P.A.; Pas, A.B. te 2021
Several studies demonstrated an increase in time spent within target range when automated oxygen control (AOC) is used. However the effect on clinical outcome remains unclear. We compared clinical... Show moreSeveral studies demonstrated an increase in time spent within target range when automated oxygen control (AOC) is used. However the effect on clinical outcome remains unclear. We compared clinical outcomes of preterm infants born before and after implementation of AOC as standard of care. In a retrospective pre-post implementation cohort study of outcomes for infants of 24-29 weeks gestational age receiving respiratory support before (2012-2015) and after (2015-2018) implementation of AOC as standard of care were compared. Outcomes of interest were mortality and complications of prematurity, number of ventilation days, and length of stay in the Neonatal Intensive Care Unit (NICU). A total of 588 infants were included (293 pre- vs 295 in the post-implementation cohort), with similar gestational age (27.8 weeks pre- vs 27.6 weeks post-implementation), birth weight (1033 grams vs 1035 grams) and other baseline characteristics. Mortality and rate of prematurity complications were not different between the groups. Length of stay in NICU was not different, but duration of invasive ventilation was shorter in infants who received AOC (6.4 +/- 10.1 vs 4.7 +/- 8.3, p = 0.029). Conclusion: In this pre-post comparison, the implementation of AOC did not lead to a change in mortality or morbidity during admission.What is Known:Prolonged and intermittent oxygen saturation deviations are associated with mortality and prematurity-related morbidities.Automated oxygen controllers can increase the time spent within oxygen saturation target range.What is New:Implementation of automated oxygen control as standard of care did not lead to a change in mortality or morbidity during admission.In the period after implementation of automated oxygen control, there was a shift toward more non-invasive ventilation. Show less
To an algebraic curve C over the complex numbers one can associate a non-negative integer g, the genus, as a measure of its complexity. One can also associate to C, via complex analysis, a g×g... Show moreTo an algebraic curve C over the complex numbers one can associate a non-negative integer g, the genus, as a measure of its complexity. One can also associate to C, via complex analysis, a g×g symmetric matrix Ω called period matrix (or equivalently, its analytic Jacobian). Because of the natural relation between C and Ω, one can obtain information of one by studying the other. In this thesis we consider the inverse problem."Given a matrix Ω, is it the period matrix associated to any curve? If so, give a model of such a curve."We focus on two families of superelliptic curves, i.e., curves of the form y^k = (x -\alpha_1)....(x - \alpha_l): Picard curves, with (k,l) = (3,4) and genus 3, and CPQ curves, with (k,l) = (5,5) and genus 6.In particular, we characterize the period matrices of said families and provide an algorithm to obtain the curve from the period matrix.We also present one application: constructing curves whose Jacobians have complex multiplication. In particular, we determine a complete list of CM-fields whose maximal order occur as the endomorphism ring over the complex numbers of the Jacobian of a CPQ curve defined over the rationals. Show less
The studies described in this thesis are aimed at improving the whole spectrum of unrelated HSCT in order to help as many patients in need of HSCT as possible. It covers three different but related... Show moreThe studies described in this thesis are aimed at improving the whole spectrum of unrelated HSCT in order to help as many patients in need of HSCT as possible. It covers three different but related topics; from access to HSCT to optimizing donor search and selection of acceptable mismatches to improving HSCT outcome. In chapter 2 we investigate access to HSCT in the Netherlands for children with relapsed acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) to see whether patients eligible for HSCT are actually offered one and what might be the reasons for not referring a patient. Chapter 3 describes the role frequent HLA haplotypes may play in donor search and what the effect may be on HSCT outcome. In chapter 4 we propose an algorithm constructed by logistic regression analysis for prediction of CTL alloreactivity. It is based on number, position and physicochemical compatibility of AA differences in class I HLA molecules. This algorithm may be effective in identifying mismatched donors acceptable for HSCT. Before we can use this algorithm clinical validation is needed. Therefore we tried to translate the use of this algorithm from in vitro CTLp assay to in vivo HSCT. Studies aiming at the prediction of outcome of HSCT are described in chapter 5. Finally in chapter 6 we tested an algorithm developed by the transplantation group in Cambridge, which focused on electrostatic and hydrophobic properties of AA differences in class I HLA molecules, on the population we used for development of our own algorithm. Their algorithm was developed for prediction of humoral alloreactivity in organ transplantation and we wondered what could be the additional impact of a similar approach on cellular alloreactivity in HSCT. Show less
The theory of complex multiplication makes it possible to construct certain class fields and abelian varieties. The main theme of this thesis is making these constructions explicit for the case... Show moreThe theory of complex multiplication makes it possible to construct certain class fields and abelian varieties. The main theme of this thesis is making these constructions explicit for the case where the abelian varieties have dimension 2. Chapter I is an introduction to complex multiplication, and shows that a general result of Shimura can be improved for degree-4 CM-fields. Chapter II gives an algorithm for computing class polynomials for quartic CM-fields, based on an algorithm of Spallek. We make the algorithm more explicit, and use Goren and Lauter___s recent bounds on the denominators of the coefficients, which yields the first running time bound and proof of correctness of an algorithm computing these polynomials. Chapter III studies and computes the irreducible components of the modular variety of abelian surfaces with CM by a given primitive quartic CM-field. We adapt the algorithm of Chapter II to compute these components. Chapters IV and V construct certain `Weil numbers'. They have properties that are number theoretic in nature and are motivated by cryptography. Chapter IV is joint work with David Freeman and Peter Stevenhagen. Chapter V is joint work with Laura Hitt O'Connor, Gary McGuire, and Michael Naehrig. Show less
