Temperature sensitivity and transition kinetics of uniform corrosion of zirconium alloys in superheated steam.

Corrosion transition during uniform corrosion of zirconium alloys receives much attention since it is the major degradation procedure. However, predicting the time and oxide thickness at transition has been hindered by the lack of knowledge about transition kinetics and how it responds to varied temperatures. Current study investigated the temperature-sensitivity of corrosion kinetics, transition behavior and microstructures of various zirconium alloys corroded in superheated steam ranging from 390 °C/10.3 MPa to 455 °C/10.3 MPa by autoclave experiment and microscopy analyses. Transition time was found to follow Arrhenius-type relationship with temperature for the first time. Both the transition oxide thickness and metastable oxide thickness increased with temperature, which was theoretically deduced and experimentally confirmed. In Zr-4 oxides, a transition thickness varying from 3.3 µm at 390 °C to 4.2 µm at 455 °C was observed. Microstructure results presented rather large HCP-ZrO particles (200∼400 nm) at O/M interface and they were even larger at the protruded positions. An intense sub-stoichiometric atmosphere was identified at O/M interface, promoting the growth of metastable oxides. The activation energy of transition kinetics was 86∼114 kJ/mol, which is close to diffusion activation energy of oxygen in tetragonal zirconia. A new model based on parabolic-law empirical relationship was thus proposed to predict transition kinetics. Predictions regarding the time to oxidation breakaway at 900-1000 °C were reported, and the results were in good agreement with the experimental data.

The Association Between Socioeconomic Factors at Diagnosis and Survival in Medulloblastoma: A Propensity Score-Matched Analysis and Population-Based Study.

BACKGROUND: Medulloblastoma (MB) is the most common malignant brain tumor of childhood. The associations between socioeconomic statuses (SES) and survival outcomes of medulloblastoma remain unclear. The aim of this study was to develop a nomogram to predict medulloblastoma specific death (MBSD) and overall survival (OS) in patients with medulloblastoma, taking into account socioeconomic factors in patients with medulloblastoma. METHODS: We included patients diagnosed with MB between 1975 and 2016 from the Surveillance, Epidemiology, and End Results database. Propensity Score Matching (PSM) was performed to reduce selection bias. Multivariate cox proportional hazards model was used to assess SES impact and clinically relevant variables of medulloblastoma specific death and overall survival. Independent prognostic factors determined by multivariate analysis were used to construct nomograms. RESULTS: A total of 2660 patients were enrolled after matching. Study showed unemployed rate (MBSD, high level vs. low level, P = 0.020) (OS, high level vs. low level, P = 0.017), and marital status (OS, married vs unmarried/unknown, P = 0.029) were important factors affecting prognosis of medulloblastoma in male. Meanwhile, median household income (MBSD, quartile 1 vs. quartile 3, P = 0.047) (OS, quartile 1 vs. quartile 2, P = 0.017) (OS, quartile 1 vs. quartile 3, P = 0.014), residence (MBSD, urban vs. rural, P = 0.041), and insurance status (MBSD, insured vs. uninsured/unknown, P = 0.002)(OS, insured vs. uninsured/unknown, P = 0.001) were significant factors affecting prognosis of medulloblastoma in female. Through the calibration plot and C-index test, our nomogram was also of predictive significance. CONCLUSIONS: The unique features of MB have provided a scenario for analysis of the impact of racial, ethnic, gender, and socioeconomic factors. The current findings have important public health implications for achieving the goal of a healthy population. Given the known morbidity rates, long-term psychological, financial and medical burdens that these children and their families must bear, it is critical to identify and address these gaps.

The application of fluorescein sodium for the resection of medulloblastoma.

INTRODUCTION: Surgical resection of medulloblastoma (MB) remains a challenge. At present, a variety of tracers have been used for intraoperative tumor visualization. However, there are few reports on the intraoperative visualization of MB. Hence, we reported our experience of applying fluorescein sodium (FS) in MB surgery. METHODS: We retrospectively analyzed the clinical information of patients with MB confirmed by surgery and pathology from January 2016 to December 2020 from Sun Yat-sen University Cancer Center. A total of 62 patients were enrolled, of which 27 received intraoperative FS and 35 did not. The intraoperative dose of FS was 3 mg/kg. RESULTS: Among the 62 patients, 42 were males, and twenty were females. The age of onset in the FS group was 9.588 ± 7.322, which in the non-fluorescein sodium group was 13.469 ± 10.968, p = 0.198. We did not find significant differences in tumor location, tumor size, tumor resection, tumor histology, and preoperative symptoms (hydrocephalus, headache, vomit, balance disorder) between the groups. There was no significant difference in the postoperative symptoms (hydrocephalus, headache, vomiting, balance disorder, and cerebellar mutism). However, patients in the FS group had a relatively low incidence of balance disorder and cerebellar mutism. There was definite fluorescence of tumor in all cases of the FS group, and even the tiny metastatic lesion was visible. No case had side effects related to the use of FS. CONCLUSIONS: FS is safe and effective in MB surgery. Whether the application of FS for surgery can reduce complications remains to be studied in the future.

Prognostic Value of the Systemic Immune-Inflammation Index and Prognostic Nutritional Index in Patients With Medulloblastoma Undergoing Surgical Resection.

Background: The progression and metastasis of cancers are associated with systematic immune inflammation and nutritional dysfunction. The systemic immune-inflammation index and prognostic nutritional index (PNI) have shown a prognostic impact in several malignancies. Therefore, our study aimed to evaluate immune inflammation and nutritional index prognostic significance in patients with medulloblastoma (MB). Methods: We retrospectively analyzed 111 patients with MB between 2001 and 2021 at our institution. The optimal cutoff values for systemic immune-inflammation index (SII), neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte counts ration (MLR), and PNI were evaluated with receiver operating characteristic (ROC) curve analysis. Clinical characteristics and SII, NLR, MLR, and PNI were tested with the Pearson's chi-squared test. The Kaplan-Meier survival curves and the Cox proportional hazards model were used to evaluate the effects of immune inflammation and nutritional index on overall survival (OS). Results: Receiver operating characteristic curve analysis determined the optimal SII, NLR, MLR, and PNI cutoff values of 2,278, 14.83, 0.219, and 56.5 that significantly interacts with OS and divided the patients into two groups. Comparative survival analysis exhibited that the high-SII cohort had significantly shorter OS (p = 0.0048) than the low-SII cohort. For the univariate analysis, the results revealed that preoperative hydrocephalus (p = 0.01), SII (p = 0.006), albumin-bilirubin score (ALBI) (p = 0.04), and coSII-PNI were predictors of OS. In the multivariate analysis, preoperative hydrocephalus (p < 0.001), ALBI (p = 0.010), SII (p < 0.001), and coSII-PNI as independent prognostic factors were significantly correlated with OS. Conclusion: The preoperative SII, ALBI, and coSII-PNI serve as robust prognostic biomarkers for patients with MB undergoing surgical resection.