Incidence and outcome of acquired demyelinating syndromes in Dutch children: update of a nationwide and prospective study

Introduction: Acquired demyelinating syndromes (ADS) are immune-mediated demyelinating disorders of the central nervous system in children. A nationwide, multicentre and prospective cohort study was initiated in the Netherlands in 2006, with a reported ADS incidence of 0.66/100,000 per year and MS incidence of 0.15/100,000 per year in the period between 2007 and 2010. In this study, we provide an update on the incidence and the long-term follow-up of ADS in the Netherlands. Methods: Children < 18 years with a first attack of demyelination were included consecutively from January 2006 to December 2016. Diagnoses were based on the International Paediatric MS study group consensus criteria. Outcome data were collected by neurological and neuropsychological assessments, and telephone call assessments. Results: Between 2011 and 2016, 55/165 of the ADS patients were diagnosed with MS (33%). This resulted in an increased ADS and MS incidence of 0.80/100,000 per year and 0.26/100,000 per year, respectively. Since 2006 a total of 243 ADS patients have been included. During follow-up (median 55 months, IQR 28–84), 137 patients were diagnosed with monophasic disease (56%), 89 with MS (37%) and 17 with multiphasic disease other than MS (7%). At least one form of residual deficit including cognitive impairment was observed in 69% of all ADS patients, even in monophasic ADS. An Expanded Disability Status Scale score of ≥ 5.5 was reached in 3/89 MS patients (3%). Conclusion: The reported incidence of ADS in Dutch children has increased since 2010. Residual deficits are common in this group, even in monophasic patients. Therefore, long-term follow-up in ADS patients is warranted

Ab initio calculation on the photochemistry of formaldehyde : the search for a hydroxycarbene intermediate

Ab initio calculations on the H2CO-HCOH rearrangement have been performed. The electronic coupling between the SI and SO surfaces, which can induce internal conversion, is calculated for this rearrangement and for the reaction coordinates leading directly to radical and molecular products. The coupling is calculated with true adiabatic Born-Oppenheimer functions, i.e., the wave functions and coupling integrals are explicitly calculated as functions of the nuclear geometry. The coupling for the hydroxycarbene rearrangement turns out to be the largest one. This indicates that the hydroxycarbene can serve as an intermediate state in the formaldehyde photochemistry. We also report calculations on the bimolecular H2COHCOH rearrangement; this interaction gives rise to a decrease of the energy barrier involved

On the comparison between crude and adiabatic Born-Oppenheimer coupling elements

A comparison is made between the coupling elements arising from the crude and the adiabatic Born-Oppenheimer approximation. It is shown, that if one includes the differences between the vibrational states in these approximation, it is possible, within the harmonic approximation, that the crude coupling elements are equal to, or even less than, the adiabatic ones. Further, it is shown, which quantities should be known to decide for the better basis set

Ab initio CI calculation of single vibronic level fluorescence emission spectra and absolute radiative lifetimes of H2CO (1A2)

Overlap integrals and dipole transition moments which were obtained by an ab initio CI calculation are used for the calculation of fluorescence emission spectra and absolute radiative lifetimes of single vibronic levels of H2CO (1A2). The agreement betwen calculation and experiment is fairly good. The analysis of the results shows that a large fraction of the total emission intensity is due to low-intensity transitions and bands at wavelengths larger than 460 nm. The implications of this result for the determination of fluorescence quantum yields and radiative lifetimes are discussed

CNDO/2 calculations on geometries of tetra- and pentacoordinated phosphoranyl radicals and UHF [unrestricted Hartree-Fock] calculations on tetracoordinated p-ligand phosphoranyl radicals

Open shell CNDO/2 calculations have been performed with geometry optimization. The calculated geometries are in agreement with the symmetry as derived from ESR data. Phosphoranyl radicals are found to have trigonal bipyramidal geometries, with the exception of digand phosphoranyl radicals, which have tetrahedron-like geometries, when strong electron withdrawing ligands are absent. In a few calculations square pyramidal geometries were considered as deviations from ideal T or TBP structures. The spin densities, however, cannot be calculated accurately with CND0/2. A n-electron model is proposed to calculate spin densities in tetracoordinated n-ligand phosphorus complexes, in which the five 3d orbitals of phosphorus are included in the calculation. These spin densities are found to be in good agreement with ESR experiments. The success of this model, where only T electrons are explicitly calculated, is explained

A study of π-conjugation in Chichibabin's - and Schlenk's - like hydrocarbons with ESR : Part I

Analysis of the ESR spectrum of the radical cation, derived from p, p'-bis-{phenyl(triphenylphosphorylidene)methyl}biphenyl reveals that spin density is found at both 31P nuclei. Zero spin density is indicated for the outer phenyl rings. In the radical cation, derived from the corresponding m,m'-isomer the spin density is delocalized over one half of the molecule and interaction is found with only one phosphorus atom. In this system the spin density in the outside ring exceeds that in the biphenyl ring. The localization of the odd electron on one half of the molecule must be caused by a strong Jahn-Teller effect. The assignment of the hyperfine coupling constants was based on spin density calculations according to the Unrestricted Hartree-Fock (UHF) method. From these calculations we also obtained an indication of the geometry of the radicals. The synthesis of these compounds is reported