Rectal diameter assessment in enuretic children-exploring the association between constipation and bladder function.

OBJECTIVES: Detrusor overactivity and constipation often co-exist in children with enuresis. Constipation is known to be linked to detrusor overactivity. The voiding chart is the best non-invasive way to investigate bladder function, whereas the ultrasonographical detection of rectal dilatation is the best way to objectify constipation. We wanted to investigate a possible relationship between the rectal diameter and voiding chart data in enuretic children. METHODS: Children with therapy-resistant enuresis were retrospectively evaluated. All had completed a voiding chart for at least 48 h. The rectal diameter was assessed ultrasonographically. The cutoff for rectal dilatation was set at 30 mm. RESULTS: We evaluated 74 patients (12 girls) aged 10.2 ± 2.8 years, 35 of whom had rectal dilatation. No significant differences in voiding chart parameters were found between children with normal versus dilated rectum. Neither did urgency or a history of daytime incontinence differ between the groups. Boys were more likely to have rectal dilatation than girls (p = 0.02). CONCLUSIONS: The absence of differences regarding voiding chart data may be explained as two mechanisms neutralizing each other: behavioral factors may make the constipated children void seldom and with large volumes, whereas detrusor overactivity caused by rectal compression of the bladder may have the opposite effect. Another option may be that the voiding chart is too blunt an instrument to detect detrusor overactivity. Constipation, and thus presumably bladder dysfunction, seems to be more important in enuretic boys than girls.

Theoretical study of phosphorescence in dye doped light emitting diodes.

Phosphorescence of platinum(II) octaethyl porphyrin (PtOEP), which has been used in organic light emitting diodes to overcome the efficiency limit imposed by the formation of triplet excitons, is studied by time-dependent (TD) density functional theory (DFT). The spin-orbit coupling (SOC) effects and the phosphorescence radiative lifetime (tau(p) (r)), calculated by the TD DFT method with the quadratic response technique, are analyzed for a series of porphyrins in order to elucidate the internal heavy atom effect on tau(p) (r). While the significance of the d(pi) orbital admixture into the lowest unoccupied molecular orbital e(g)(pi(*)), proposed by Gouterman et al. [J. Chem. Phys. 56, 4073 (1972)], is supported by our SOC calculations, we find that the charge-transfer (CT) mechanism is more important; the CT state of the (3)A(2g) symmetry provides effective SOC mixing with the ground state, and a large (3)A(2g)-(3)E(u) transition dipole moment gives the main contribution to the radiative phosphorescence rate constant. The IR and Raman spectra in the ground state and first excited triplet state (T(1)) are studied for proper assignment of vibronic patterns. An orbital angular momentum of the T(1) state is not quenched completely by the Jahn-Teller effect. A large zero-field splitting is predicted for PtP and PtOEP which results from a competition between the SOC and Jahn-Teller effects. A strong vibronic activity is found for the e(g) mode at 230 cm(-1) in PtP phosphorescence which is shifted to 260 cm(-1) in PtOEP. This out-of-plane vibration of the Pt atom produces considerable change of the SOC mixing. The role of charge-transfer state of d(pi)pi(*) type is stressed for the explanation of the electroluminescent properties of the dye doped light emitting diode.

Application of density functional theory for studies of excited states and phosphorescence of platinum(II) acetylides.

The electronic states of different conformations of platinum acetylides Pt(PH3)2(C[triple bond]C-Ph)2 and Pt(PH3)2(C[triple bond]C-PhC[triple bond]C-Ph)2 (PE1 and PE2) were calculated with density functional theory (DFT) using effective core potential basis sets. Time dependent DFT calculations of UV absorption spectra showed strong dependence of the intense absorption band maxima on mutual orientation of the phenyl rings with respect to the P-Pt-P axis. Geometry optimization of the first excited triplet state (T1) indicates broken symmetry structure with the excitation being localized in one ligand. This splits the two substitution ligands into a nondistorted aromatic ring with the C[triple bond]C-Ph bonds for one side and into a quinoid structure with a cumulenic C=C=C link on the other side. Quadratic response (QR) calculations of spin-orbit coupling and phosphorescence radiative lifetime (tauR) indicated a good agreement with experimental tauR values reported for solid PE1 and PE2 and PE2 capped with dendrimers in tetrahydrofuran solutions. The QR calculations reproduced an increase of tauR upon prolongation of pi chain of ligands and concommittant redshift of the phosphorescence. Moreover, it is shown how the phosphorescence borrows intensity from sigma-->pi* transitions localized at the C[triple bond]C-Pt-P fragments and that there is no intensity borrowing from delocalized pi-->pi* transitions.

Evaluation of low-scaling methods for calculation of phosphorescence parameters.

In order to find a methodology that is a compromise between favorable computational scaling and tolerable errors, a series of nonrelativistic approaches for the calculation of radiative phosphorescence lifetimes are benchmarked against fully relativistic four-component results. The study of the a 3A2-X 1A1 transition intensity in the series of H2CX molecules, where X is a chalcogene atom, X={O,S,Se,Te}, indicates a general good agreement between fully relativistic four-component and nonrelativistic perturbation-theoretical calculations. Among the nonrelativistic approaches, the scaled-charge spin-orbit operator approach is recognized as to provide transition matrix elements that are in good agreement with those obtained with the more elaborate Breit-Pauli and atomic mean field spin-orbit operators. This finding supports phosphorescence calculations using the available linear scaling technology for large complexes and, together with effective-core potentials, large complexes including heavy elements.