Design of organic molecules with large two-photon absorption cross sections.

A strategy for the design of molecules with large two-photon absorption cross sections, delta, was developed, on the basis of the concept that symmetric charge transfer, from the ends of a conjugated system to the middle, or vice versa, upon excitation is correlated to enhanced values of delta. Synthesized bis(styryl)benzene derivatives with donor-pi-donor, donor-acceptor-donor, and acceptor-donor-acceptor structural motifs exhibit exceptionally large values of delta, up to about 400 times that of trans-stilbene. Quantum chemical calculations performed on these molecules indicate that substantial symmetric charge redistribution occurs upon excitation and provide delta values in good agreement with experimental values. The combination of large delta and high fluorescence quantum yield or triplet yield exhibited by molecules developed here offers potential for unprecedented brightness in two-photon fluorescent imaging or enhanced photosensitivity in two-photon sensitization, respectively.

Two-Photon Fluorescence Excitation Cross Sections of Biomolecular Probes from 690 to 960 nm.

We report on two-photon fluorescence excitation (TPE) action cross sections for five widely used molecular fluorophores. Measurements were performed by use of ultrashort (~100-fs) Ti:sapphire pulsed excitation over the range 690-960 nm. TPE spectra were obtained by comparison with a fluorescein calibration standard. Large cross sections were found for the cyanine reagent Cy 3 (~140 GM) and for Rhodamine 6G (~150 GM), both at 700 nm [1 GM = 10(-50) (cm(4) s)/photon]. Several fluorophores show interesting and desirable blue shifts with respect to twice the one-photon absorption wavelength. Fluorophore fluorescence intensities showed no significant departure (?4%) from quadratic illumination power dependence, indicating genuine two-photon processes. Implications of these measurements for two-photon laser-scanning microscopy are discussed.

[Health policy goals in child and adolescent health reporting--evaluation with reference to an intermediate-term evaluation]. / Gesundheitspolitische Ziele in der Kinder- und Jugendgesundheitsberichterstattung--Evaluation in Form einer Zwischenbilanz.

As a result of the first report on the health of children in Hamburg (1990) 14 primary health policy objectives were identified and related to specific intervention fields. The health information system group at Hamburg has prepared an interim evaluative statement for 1994 on whether and how far each objective has been achieved compared to the targets formulated for the years 1995 and 2000 respectively. 8 out of 14 objectives are considered remaining unchanged as before (i.e. unintentional conception), either proceeding towards the target (i.e. low birth weight, dental health) or having reached the target for 1995 (i.e. infant mortality, age-appropriate vaccination). With 4 objectives the trend deteriorated (i.e. body weight of teenagers, accidents). One objective was monitored on the basis of a new data source (violence against children) and for one objective information could not be proved or updated (breast feeding). In traditional areas of local health policy (i.e. dental health, infant mortality) the health information system and the health targets may be sufficient to help improve the health of the city. In non-lobbied fields (i.e. breast feeding) or those without a consensus on responsibilities (i.e. violence, health and social discrimination) health reports on their own do not invoke achievements, but need to be supported by additional measures.