Synthesis Characterization And Photopolymerization Of Novel Phosphonated Materials

New phosphonated cross-linked materials were synthesized from telomers obtained by reaction between 10-undecenol and dialkyl hydrogenphosphonates. Telomers were then converted to materials resins by methacrylation reactions. Finally, photopolymerization of the different materials synthesized was achieved and influence of the nature of the phosphonate group (diester, monoacid and diacid) was also evaluated.New phosphonated cross-linked materials were synthesized from telomers obtained by reaction between 10-undecenol and dialkyl hydrogenphosphonates. Telomers were then converted to materials resins by methacrylation reactions. Finally, photopolymerization of the different materials synthesized was achieved and influence of the nature of the phosphonate group (diester, monoacid and diacid) was also evaluated

Application of luminescent detectors in quality assurance of clinical electron beam

International audienceThermoluminescent dosimeters (TLD) are widely applied in quality assurance of external radiotherapy beam. The aim of this study is to check the possible use of radiophotoluminescent glass dosimeters (RPLGD), and optically stimulated luminescent dosimeters (OSLD) in quality assurance of clinical electron beam (used in radiotherapy treatments). For this purpose, we give in this paper, an estimation and a comparison of dosimetric parameters, characterizing dose profile and percentage depth dose (PDD) curves, for electron beam using the different studied detectors. The Monte Carlo MCNP5 simulation code was utilized to calculate the distribution of deposited energy along X-axis and PDD curves in a water phantom using RPLGD (FD-7glass), TLD (LiF: Mg, Ti) and OSLD (Al2O3:C) for electron beam energies of 9, 12, 16 and 20 MeV. Our calculations show that the profiles for different electron energies are almost identical for all used materials: we found similar average penumbra and full width at half maximum (FWHM). For flatness and symmetry, our results show a good correspondence with the recommended values where the flatness and symmetry calculated in all dosimeters materials are less than 1.7%. We also found concordance with the literature for the parameters derived from PDD curves, such as various ranges (R100, R90, R80, R50 and Rp) and energies specification (Ep,o and E0) for different electron beams (9, 12, 16 and 20 MeV). In conclusion, this study demonstrates a good correspondence with the results of measurements and Monte Carlo simulations found in the literature. RPLGD and OSLD can be as TLD useful detectors for quality assurance (QA) verifications concerning dose profile and PDD curve for clinical electron beam. Further research is recommended to broaden the scope of the current study

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

Background: The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications. Methods: ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery. Results: The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784. Conclusions: This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance. © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.Medical Research Council of South Africa gran