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Objective: Exophytic gliomas of the medulla are rare childhood tumors that mostly are pilocytic astrocytomas. Here we report our experience in 11 ‑children with this rare tumor. Methods: A retrospective study was performed using the records of children with exophytic gliomas of the medulla at Children's Hospital Medical Center in Tehran, Iran, from 2002 through 2013. The general, clinical, and radiological data and follow-up of all patients were reviewed. Results: The patients mostly were male aged from 11 months to 7 years. Swallowing problems, failure to thrive and nausea and vomiting were the most common symptoms. The time span between the onset of symptoms and the diagnosis was 2-24 months. Gross total resection of tumor was possible in 8 patients. Most tumors were pilocytic astrocytomas. Patients were followed for 2 months to 11 years (mean = 3.6 years). There was no intraoperative mortality. Recurrence occurred in 1 child with fibrillary astrocytoma. Conclusion: Gross total resection of symptomatic dorsal exophytic medullary glioma is recommended. Most tumors are pilocytic astrocytomas. The attachment of these tumors to important brainstem structures usually inhibits total resection. Electrophysiological monitoring of sensorimotor pathways and cranial nerves can be helpful to preserve surrounding neural tissue during tumor resection and to minimize complications. Regular follow-up of patients with clinical examination and brain MRI is mandatory. Repeated surgery, radiation therapy and chemotherapy are suggested in cases with tumor recurrence or progression.

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A high pressure carbon dioxide (CO2) absorption from a specific gas in a conventional column has been evaluated by the Aspen HYSYS simulator using a wide range of single absorbents and blended solutions to estimate the outlet CO2 concentration, absorption efficiency and CO2 loading to choose the most proper solution in terms of CO2 capture for environmental concerns. The property package (Acid Gas-Chemical Solvent) which is compatible with all applied solutions for the simulation in this study, estimates the properties based on an electrolyte non-random two-liquid (E- NRTL) model for electrolyte thermodynamics and Peng-Robinson equation of state for the vapor and liquid hydrocarbon phases. Among all the investigated single amines as well as blended solutions, piperazine (PZ) and the mixture of piperazine and monoethanolamine (MEA) have been found as the most effective absorbents respectively for CO2 absorption with high reactivity based on the simulated operational conditions.