Electron injection into organic semiconductor devices from high work function cathodes.

We show that polymer light-emitting diodes with high work-function cathodes and conjugated polyelectrolyte injection/transport layers exhibit excellent efficiencies despite large electron-injection barriers. Correlation of device response times with structure provides evidence that the electron-injection mechanism involves redistribution of the ions within the polyelectrolyte electron-transport layer and hole accumulation at the interface between the emissive and electron-transport layers. Both processes lead to screening of the internal electric field and a lowering of the electron-injection barrier.

Vaginal colonization with mycoplasma hominis and ureaplasma urealyticum.

Vaginal cultures obtained from unselected young women who consulted the gynecologist in a student health service were examined for Ureaplasma urealyticum and Mycoplasma hominis. Each participant completed a confidential questionnaire. Multiple logistic regression analysis was used to determine which variables, of a large number ascertained, were associated with mycoplasmal colonization.

Sexually transmitted conditions among women college students.

We studied 500 unselected young women who consulted a gynecologist in a student health service. Most participants were symptom-free and had normal physical examinations. Few sexually transmitted infections were encountered.

Chlamydia trachomatis in women: antibody in cervical secretions as a possible indicator of genital infection.

One hundred eighty-five women college students were examined for genital infection with Chlamydia trachomatis. This organism was isolated from nine (5%) of the 185 women. Antibody was demonstrated in the genital secretions of 26 (14%) and in the serum of 70 (38%) of the women.

Vaginal colonization with Corynebacterium vaginale (Haemophilus vaginalis).

Vaginal cultures for Corynebacterium vaginale and confidential questionnaires were obtained from unselected young women who consulted a gynecologist in a student health service. In all, 466 women were studied, 150 (32.2%) of whom were colonized with C.