Incorporation of spent ion exchange resin simulate into cement composites.

Solidification/Stabilization (S/S) of spent radioactive ion exchange resins (IER) is one of many critical problems facing developing nuclear industries all over the world. Immobilization technology using Ordinary Portland Cement (OPC) as an inert matrix, has been widely applied for the solidification/stabilization of spent ion exchange resin. In this study incorporation of simulated IER into cement matrix and characterization of the final solid waste form (FWF) had been searched practically in laboratory scale experiments. Factors that can affect the properties of the FWF including the water/cement (w/c) ratios and the resin concentration were studied systematically. Mechanical integrities, thermal analysis, and mass loss during hardening and curing for 28 days were evaluated for FWF hard blocks. Scanning Electron Microscope (SEM) and X-Ray Diffraction (X-RD) examinations were performed to investigate the internal architecture of the FWF. Moreover, the heat of cement hydration reactions was recorded during the IER solidification process. Based on the experimental results obtained, it is worth to state that according to its acceptable characteristics and advantages of cement as an inert matrix, it can be suggested safely for the immobilization of untreated spent radioactive ion exchange resins.

Clinical and Ultrasound Evaluation of Early Threatened Miscarriage to Predict Pregnancy Continuation up to 28 Weeks: A Prospective Cohort Study.

OBJECTIVES: (1) To study the predictors of pregnancy continuation up to 28 weeks in first-trimester threatened miscarriage after a single clinical and ultrasound (US) evaluation. (2) To assess the role of both clinical and US predictors in counseling and decreasing repeated emergency follow-up scans. METHODS: A prospective observational study that included a cohort of 241 patients with threatened miscarriage (≥6-12 weeks) was conducted. They had a single clinical and US evaluation, and then they were contacted by weekly phone calls until completing 28 weeks' gestation or reporting miscarriage. Independently, all patients were followed by the recommended routine US scanning with or without emergency visits. RESULTS: Two hundred thirty-three patients completed the study, of whom 193 patients continued up to 28 weeks' gestation, and 40 miscarried (17.1%). Only spotting/mild bleeding episodes and progesterone treatment were the clinical predictors of fetal viability. The embryonic/fetal heart rate (E/FHR) was the best single US predictor, with a specificity and positive predictive value of 95.3% and 97.2%, respectively. Combining 3 US parameters, at their best cutoff points (E/FHR >113 beats per minute, crown-rump length >19.9 mm, and gestational sac diameter >27.3 mm), had a specificity and positive predictive value of 98% and 99% (first-trimester US triad of fetal viability). CONCLUSIONS: [1] In first-trimester threatened miscarriage, clinical parameters that could predict fetal viability included spotting/ mild bleeding and progesterone treatment. [2] After a single US scan, the presence of at least an E/FHR of greater than 113 bpm or the suggested first-trimester US triad appeared as a simple, measurable, and effective predictor of pregnancy continuation up to 28 weeks. [3] These US predictors are not to replace the recommended scheduled scanning during pregnancy. [4] This can improve patients' counseling and decrease the need for repeated emergency follow-up scans. Otherwise, there is an indication for repeating US scans at a 1-week to 10-day interval.