The interactions between an anionic surfactant viz. sodium dodecylbenzenesulfonate (SDBS) and nonionic surfactants with different secondary ethoxylated chain length viz.Tergitol 15-S-12, Tergitol 15-S-9 and Tergitol 15-S-7 have been studied in the present paper. An attempt has also been made to investigate the effect of ethoxylated chain length on the micellar and the thermodynamic properties of the mixed surfactant systems. The micellar properties like critical micelle concentration (CMC), micellar composition (X A ), interaction parameter (β) and the activity coefficients (f A and f NI ) have been evaluated using Rubingh's regular solution theory (RST). In addition to micellar studies, thermodynamic parameters like the surface pressure (Π CMC ), surface excess values (Г CMC ), average area of the monomers at the air-water interface (A avg ), free energy of micellization (ΔG m ), minimum energy at the air-water interface (G min ) etc. have also been calculated. It has been found that in mixtures of anionic and nonionic secondary Downloaded by [University of Aberdeen] at 23:38 27 December 2014 2 ethoxylated surfactants, a surfactant containing a smaller ethoxylated chain is favored thermodynamically. Additionally the adsorption of nonionic species on air/water interface and micelle increases with decreasing secondary ethoxylated chain length.Dynamic light scattering (DLS) and viscometric studies have also been performed to study the interactions between anionic and nonionic surfactants used.

Objective: Image based prediction of molecular subgroups of Medulloblastoma (MB) has the potential to optimize and personalize therapy. The objective of the study is to distinguish between broad molecular subgroups of MB using MR–Texture analysis. Methods: Thirty-eight MB patients treated between 2007–2020 were retrospectively analyzed. Texture analysis was performed on contrast enhanced T1(T1C) and T2 weighted(T2W) MR images. Manual segmentation was performed on all slices and radiomic features were extracted which included first order, second order (GLCM - Grey level co-occurrence matrix) and shape features. Feature enrichment was done using LASSO (Least Absolute Shrinkage and Selection Operator) regression and thereafter Support Vector Machine (SVM) and a 10-fold cross-validation strategy was used for model development. The area under Receiver Operator Characteristic (ROC) curve was used to evaluate the model. Results: A total of 174 and 170 images were obtained for analysis from the Axial T1C and T2W image datasets. One hundred and sixty-four MR based texture features were extracted. The best model was arrived at by using a combination of 30 GLCM and six shape features on T1C MR sequence. A 10-fold cross-validation demonstrated an AUC of 0.93, 0.9, 0.93, and 0.93 in predicting WNT, SHH, Group 3, and Group 4 MB subgroups, respectively. Conclusion: Radiomic analysis of MR images in MB can predict molecular subgroups with acceptable degree of accuracy. The strategy needs further validation in an external dataset for its potential use in ab initio management paradigms of MBs. Advances in knowledge: Medulloblastoma can be classified into four distinct molecular subgroups using radiomic feature classifier from non-invasive Multiparametric Magnetic resonance imaging. This can have future ramifications in the extent of surgical resection of Medulloblastoma which can ultimately result in reduction of morbidity.

Background We present our institutional approach for re-irradiation in diffuse intrinsic pontine glioma and their outcomes. Methods Consecutive patients of recurrent diffuse intrinsic pontine glioma treated with re-irradiation (January 2015–September 2019) were reviewed retrospectively to describe the clinical-response-based approach followed for the dose and volume decision. Outcomes were defined with clinical and steroid response criteria and survival endpoints included progression-free survival and overall survival as cumulative(c) overall survival and re-irradiation overall survival (re-irradiation starting to death). The Kaplan–Meier method and log-rank test were used for survival analysis. Results Twenty-patient cohort with a median (m) age of 7.5 years, m-progression-free survival of 8.4 months and m-Lansky performance score of 50 received re-irradiation of which 17 (85%) were called clinical responders. The median re-irradiation-overall survival with 39.6–41.4, 43.2 and 45 Gy were 5.8, 7 and 5.3 months, respectively. One-month post-re-irradiation steroid independent status was a significant predictor of better survival outcomes (overall survival, P≤0.004). No ≥ grade 3 toxicities were noticed. Two patients succumbed to intra-tumoral hemorrhage. Conclusions Higher doses of re-irradiation based on a clinical-response-based approach show improvement in survival and steroid dependence rates with acceptable toxicity. Steroid independent status at 1-month post-re-irradiation predicts better outcomes. Prospective studies may validate this with quality of life data.

Background and Purpose: Highergrade glial neoplasms undergo standard treatment with surgery, radiotherapy, and alkylating agents. There is often a clinical/neuroimaging dilemma in the post-treatment setting to differentiate disease recurrence from treatment-related changes. FET (fluoro-ethyl-tyrosine) PET has emerged as a molecular imaging modality for cases where MR imaging is inconclusive. This study aims to develop a cutoff on FET PET for differentiating true recurrence from post-treatment changes. Methods:We retrospectively analyzed72 patientswith post-treatment grade 3 or 4 brain gliomas. Five to six mCi of 18 F-FET was injected and static imaging of the brain was performed at 20 min. A tumor-to-white matter (T/Wm) ratio was used as semiquantitative parameter. A T/Wm cutoff of 2.5 was used for image interpretation. Imaging findings were confirmed by either histopathologic diagnosis in a multidisciplinary joint clinic or based on follow-up of clinical and neuroimaging findings.Results: Forty-one of 72 patients (57%) showed recurrent disease on FET PET. Thirty-five of them were confirmed to have tumor recurrence; six patients showed post-treatment changes. Thirty-one of 72 patients (43%) showed post-treatment changes on FET PET; 27 were confirmed as post-treatment change and four patients had tumor recurrence on subsequent MR imaging. An optimum T/Wm cutoff of 2.65 was derived based on receiver operating characteristic analysis with a sensitivity of 80% and specificity of 87.5%. Conclusion:Static FET PET can be used as problem-solving imaging modality with a T/Wm cutoff of 2.65 to differentiate late recurrence from post-treatment changes in grade 3 or 4 brain gliomas with equivocal MR features.