We have determined the wavelength dependence of group refractive indices for crystals of thiophene/phenylene co-oligomers (TPCOs). We calculated the group indices from the broadband interference modulation of the emission spectra. The interference is caused by a pair of parallel crystal edges that function as an optical resonator. These indices steeply increased with decrease in wavelengths and were in good agreement with those estimated from the mode intervals of the longitudinal multimode at the laser oscillation. Furthermore, we derived the dispersion of phase refractive indices on the basis of the Sellmeier dispersion equation. These refractive indices gradually increased with decrease in wavelengths and ranged 2.5–3.2 for the materials. The implications of the experimental results are discussed.

The decay and transport of triplet excitons photogenerated via singlet exciton fission in polycrystalline and single-crystalline pentacene is reported. Using transient absorption spectroscopy, we find evidence for diffusion-mediated triplet-triplet annihilation. We estimate monomolecular lifetimes, bimolecular annihilation rate constants, and triplet exciton diffusion lengths. We discuss these results in the context of current solar cell device architectures.

Unusual time-delayed pulse emissions with spectrally narrowed band splitting were observed from a single-crystal thiophene/phenylene co-oligomer at room temperature. Under pulsed optical excitation, the Fabry–Pérot lasing oscillation caused by a pair of the crystal facets emerges with peculiar spectral splitting in the prethreshold fluence range. Time-resolved measurements of those “prethreshold lasing” peaks reveal a pulse-shaped profile with a time delay up to 300 ps. This observation is not explained in terms of usual cooperative interaction reported as superfluorescence for inorganic emitters at low temperature, but might be more relevant to unknown phase correlation overwhelming thermal perturbation among perfectly aligned molecules.

We have fabricated light‐emitting field‐effect transistors (LEFETs) using p‐type organic crystals directly grown onto a two‐dimensional polymer diffraction grating made of a triangular lattice of circular air holes. An n‐type organic thin film was inserted between the crystal and the metal electrode. Distinct current‐injected spectrally narrow linewidth emissions (NLEs) were observed under application of alternating‐current voltages to the gate contact. The NLE peaks were related to the combined refractive index of the p‐type crystal and the grating. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The present study consists of 651 cases of soft tissue tumors originating in the head and neck area. Among these tumors 628 were benign (96y0), while there were only 23 malignant cases (4%). In the benign group hemangiomas showed the highest incidence (47%) followed by tumors of adipose tissue (19%) and those of peripheral nerves (12%). Rare tumors consisted of nodular fasciitis, hibernoma, lipoblastomatosis, glomus tumor, granular cell tumor, and chondroma. The majority of cases in the malignant group were either those of muscle origin or blood vessel origin. Excepting for two cases of rhabdomyosarcoma of the embryonal type and two cases of angiosarcoma, all showed recurrence andlor metastasis and terminated in death. Three cases of liposarcoma of either well-differentiated or myxoid type had a good prognosis with all three living for 3 or more years without any recurrence. Other malignant tumors consisted of malignant schwannoma, fibrosarcoma, malignant fibrous histiocytoma, alveolar soft part sarcoma, and chordoma. The age, sex, anatomical location, and differential diagnosis have also been described. ACTA PATH. JAP. 29: 389-408, 1979. The clinical records and materials of 651 cases collected from the Jikei University Hospital and other sources were reviewed and analyzed. Brief descriptions of surgical materials were made when possible, and they were all fixed in either 10% or 20% buffered formalin. Paraffin blocks were prepared, cut a t 3 4 microns, and stained with hematoxylin-eosin and Masson trichrome (modified by Noguchi and Matsumoto). Phosphotungstic acid-hematoxylin, periodic acid-Sch8 with or without diastase digestion, alcian blue, Sudan 111, and silver impregnation were applied when necessary. Results Benign Soft Tissue Tumors of the Head and NeckThe tumors were classified according to the histological classification of soft tissue tumors advocated by the WHO International Reference Centre. 29(3): 1979 Y . MAKINO 391 392 SOFT TISSUE TUMORS OF HEAD AND NECK Acta Path. Jap. 29(3): 1979Y. MAEINO