Studies of photoreflectance spectra in Cd(1-x)Mn(x)Te/CdTe superlattices with high compositions

Photoreflectance spectra of Cd(1-x)Mn(x)Te/CdTe superlattices with high compositions x = 0. 4,0. 8 were carried out at room temperature and liquid nitrogen temperature. The samples were grown by molecular beam epitaxy (MBE) technique. Exciton transitions of heavy-and light-holes related to 11H,22H,33H and 11L were observed. After taking into consideration the strain-induced and quantum confinement effects, the theoretical calculations are in very good agreement with our photo-reflectance measurement results except 33H of x = 0.8. Photoluminescence spectra were also performed at room temperature and low temperature in order to compare with our photoreflectance results

Resection of Primary Tumor at Diagnosis in Stage IV-S. Neuroblastoma: does it affect the clinical course?

PURPOSE: To determine whether resection of primary tumor has a favorable influence on outcome of infants (age 0 to 11 months) with stage IV-S neuroblastoma. PATIENTS AND METHODS: Between March 1976 and December 1993, 97 infants with previously untreated neuroblastoma diagnosed in 21 Italian institutions were classified as having stage IV-S disease. Seventy percent were younger than 4 months. Adrenal was the primary tumor site in 64 of 85 patients with a recognizable primary tumor. Liver was the organ most often infiltrated by the tumor (82 patients), followed by bone marrow and skin. RESULTS: The overall survival (OS) rate at 5 years in 80% and event-free survival (EFS) rate 68%. In 24 infants, the effect of resection of primary tumor could not be evaluated because of rapidly fatal disease progression (n = 8), absence of a primary tumor (n = 12), or partial resection (n = 4). Of 73 assessable patients, 26 underwent primary tumor resection at diagnosis: one died of surgical complications, one relapsed locally and died, and two others relapsed (one of these two locally) and survived, for a 5-year OS rate of 92% and EFS rate of 84%. Of the remaining 47 patients who did not undergo primary tumor resection at diagnosis 11 suffered unfavorable events, of whom five died, for an OS rate of 89% and EFS rate of 75% (no significant difference from previous group). Disease recurred at the primary tumor site in only one five who died, and in only one of six survivors of progression or relapse; in these patients, the primary tumor, located in the mediastinum, was successfully resected. CONCLUSION: Infants who underwent resection of the primary tumor at diagnosis had no better outcome than those in whom the decision was made not to operate