On modeling of the evaporation of chemical warfare agents on the ground

A model for evaporation of chemical warfare agents on the ground has been developed. The process of evaporation is described in three steps: (1) the immediate drop enlargement due to impact momentum is modeled using an empirical correlation from technical literature; (2) further enlargement caused by capillary spreading upon the surface and the simultaneous sorption into the substrate, modeled in three dimensions; (3) subsequent drying and redistribution of the sorbed material is described as a one-dimensional (vertical) process. The formulation of the flux in the soil takes into account vapour, liquid, solute, and adsorbed phases. The evaporation from the surface is determined by the vapour concentration at the surface and the conditions in the atmospheric viscous sub-layer close to the droplet spots on the surface. Model results agree with the limited experimental data found in the literature. The model shows a very rapid sorption and redistribution of chemical warfare droplets on sand. This effect gives a rapid decrease of the evaporation, except for a shorter initial period. However, a small residual evaporation exists for a rather long time from liquid, which has penetrated down into the soil. © 1998 Elsevier Science B.V

Quality-adjusted survival in women with gynecologic malignancies receiving IMRT after surgery: A Ppatient Rreported Ooutcome study of NRG oncology\u27s RTOG 1203

Introduction: NRG/RTOG 1203 compared 3-D conformal radiotherapy (3D CRT) to intensity-modulated radiotherapy (IMRT) in patients with endometrial or cervical cancer requiring post-operative radiotherapy after hysterectomy. The purpose of this study was to report the first quality-adjusted survival analysis comparing the two treatments. Methods: NRG/RTOG 1203 randomized patients having undergone hysterectomy to either 3DCRT or IMRT. Stratification factors included RT dose, chemotherapy, and disease site. The EQ-5D, both index and visual analog scale (VAS), were obtained at baseline, 5 weeks after the start of RT, 4–6 weeks post RT and 1 and 3-years post RT. EQ-5D index and VAS scores along with quality-adjusted survival (QAS) were compared between treatment arms using the t-test at a two-sided significance level of 0.05. Results: NRG/RTOG 1203 enrolled 289 patients of which 236 consented to participate in the patient reported outcome (PRO) assessments. QAS was higher in women treated with IMRT, 1374 vs 1333 days (p = 0.5) compared to patients treated with 3DCRT, but this difference was not statistically different. Patients treated with IMRT had less of a decline in VAS score 5 weeks post RT, −5.04, compared to patients treated with 3DCRT, −7.48, although not statistically significant (p = 0.38). Conclusion: This is the first report of the use of the EQ-5D comparing two radiotherapy techniques in the treatment of gynecologic malignancies after surgery. While there were no significant differences in QAS and VAS scores between patients who received IMRT vs. 3DCRT, RTOG 1203 was not powered to show statistical differences in these secondary endpoints