Colloidal semiconductor nanocrystals are promising luminophores for creating a new generation of electroluminescence devices. Research on semiconductor nanocrystal based light-emitting diodes (LEDs) has made remarkable advances in just one decade: the external quantum efficiency has improved by over two orders of magnitude and highly saturated color emission is now the norm. Although the device efficiencies are still more than an order of magnitude lower than those of the purely organic LEDs there are potential advantages associated with nanocrystal-based devices, such as a spectrally pure emission color, which will certainly merit future research. Further developments of nanocrystal-based LEDs will be improving material stability, understanding and controlling chemical and physical phenomena at the interfaces, and optimizing charge injection and charge transport.

We derive black hole masses for a sample of about 300 AGNs in the redshift range 0 < z < 2.5. We use the same virial velocity measure (FWHM Hβ BC ) for all sources which represents a significant improvement over previous studies. We review methods and caveats for determining AGN black hole masses via the virial assumption for motions in the gas producing low ionization broad emission lines. We derive a corrected FWHM(Hβ BC ) measure for the broad component of Hβ that better estimates the virialized line emitting component by comparing our FWHM measures with a sample of reverberated sources with Hβ radial velocity dispersion measures. We also consider the FWHM of the Feiiλ4570 blend as a potential alternative velocity estimator. We find a range of black hole mass between log M BH ∼ 6.0-10.0, where M BH is in solar masses. Estimates using corrected FWHM(Hβ), as well as FWHM (Feii) measures, reduce the number of sources with log M BH > 9.5 and suggest that extremely large M BH values (log M BH > ∼ 10) may not be realistic. Derived L/L Edd values show no evidence for a significant population of super-Eddington radiators especially after correction is made for sources with extreme orientation to our line of sight. Sources with FWHM(Hβ BC ) < ∼ 4000 km s −1 show systematically higher L/L Edd and lower M BH values than broader lined AGNs (including almost all radio-loud sources).

This prospective study was designed to evaluate the incidence of lichen sclerosus et atrophicus (LSA) in a pediatric population with hypospadias and phimosis in order to discuss the indications for circumcision and utilization of preputial skin for urethral surgery. All 115 boys, 55 with congenital phimosis, 45 with acquired phimosis, 13 with hypospadias, and 2 with recurrent chronic balanitis, underwent full-thickness biopsies of the foreskin that were examined by a single pathologist. Of the patients with acquired phimosis, 88% showed inflammatory features in the foreskin; 60% had LSA. Of the patients with congenital phimosis, 82% showed inflammatory disease in the prepuce; 30% had LSA. Of the patients operated upon for hypospadias, 61% showed histologic findings of chronic inflammation of the foreskin and LSA was evident in 15%. The high incidence of LSA in the prepuce of patients with phimosis suggests that circumcision should be performed to correct this disease. The frequent presence of chronic inflammation is a possible cause of stenosis when the foreskin is used to perform a urethroplasty in patients with hypospadias.

This study confirms that the minimally invasive approach is safe and effective for the treatment of primary gastroesophageal reflux disease in children.