Experimental and theoretical study of the enthalpy of formation of 3,6-diphenyl-1,2,4,5-tetroxane molecule.

We report the results obtained for the experimental determination and the theoretical calculation of the enthalpy of formation of 3,6-diphenyl-1,2,4,5-tetroxane molecule. The experimental work was performed using a macrocalorimeter to measure the combustion heat, and the sublimation enthalpy was determined via the measurement of the vapor pressure at equilibrium with the vapor phase at different temperatures resorting to the Clapeyron-Claussius equation. Theoretical calculations were performed using semiempirical AM1 and PM3 methods as well as ab initio techniques at the 3-21, 6-31G(d,p), and 6-311G(d,p) basis set levels.

[Bladder tumor lethality. Results in the autonomous community of Rioja between 1975-1991]. / Letalidad por tumor vesical. Resultados en la comunidad autónoma de la Rioja entre los años 1975-1991.

Between 1975-1991, a total of 557 cases of bladder carcinoma were identified in the Autonomous Community of La Rioja (CAR) which were followed up to December 1994. The overall lethality was 21.9%. 492 cases with 22.35% lethality were identified in males. In females, however, there was 65 cases with 18.46% lethality. The comparison of males and females lethality resulted in p = 0.525. Lethality between cases diagnosed within each 5-year period analyzed is: 1975-1981: 177 cases, lethality 23.72%. 1982-1986: 168 cases, lethality 30.95%. 1987-1991: 212 cases, lethality 13.20%. Between the first and the second 5-year periods, p = 0.132; between the first and third 5-year periods p = 0.007 and between the second and third 5-year periods p < 0.000. Bladder tumours accounts in CAR for a 22.35% lethality. Lethality is higher in males that in females but the difference is not statistically significant. In the last 5-year period assessed, 1987-1991, a reduction of lethality from bladder neoplasms has been documented.

[Bladder cancer survival, study of 557 cases identified at the autonomous community of La Rioja from 1975 to 1991]. / Supervivencia por cáncer de vejiga, estudio de 557 casos identificados en la Communidad Autónoma de La Rioja entre 1975 y 1991.

OBJECTIVE: To analyze survival in 557 cases of bladder cancer that had been detected in La Rioja (Spain) from 1975 to 1991. METHODS/RESULTS: The Kaplan Meier and Mantel and Haenszel methods were used for the statistical analyses. The survival rate for each 5-year period analyzed was 69%, 58% and 73%, respectively. Most deaths occurred within the first 24 months. The survival rates were 25%, 21% and 0%, respectively, for infiltrating tumors and 84%, 76% and 85% for superficial tumors was of the. The survival rates for males and females were not statistically significant. CONCLUSION: The survival rate in patients with bladder cancer has increased. Patients with infiltrating bladder tumors have a worse prognosis. The survival rates for males and females are not statistically significantly different.