Self-propagating combustion synthesis of intermetallic matrix composites in the ISS

Combustion Synthesis experiments have been performed on the ISS (International Space Station) during the Belgian taxi-flight mission ODISSEA in November 2002, in the framework of the ESA-coordinated project COSMIC (Combustion Synthesis under Microgravity Conditions). The main objective of the experiments was to investigate the general physico-chemical mechanisms of combustion synthesis processes and the formation of products microstructure. Within the combustion zone, a number of gravity-dependent phenomena occur, while other phenomena are masked by gravity. Under certain conditions, gravity-dependent secondary processes may also occur in the heat-affected zone after combustion. To study the influence of gravity, a specially dedicated reactor ensemble was designed and used in the Microgravity Science Glovebox (MSG) onboard the ISS. In this work, the experiment design is first discussed in terms of the experimental functionality and reactor ensemble integration in the MSG. To investigate microstructure formation, a sample constituted by a cylindrical portion followed by a conical one, the latter being inserted inside a massive copper block, is used. The experiment focused on the synthesis of intermetallic matrix composites (IMCs) based on the Al-Ti-B system. Depending on the composition, different intermetallic compounds (TiAl and TiAl3) can be formed as matrix phase while TiB2 represents the reinforcing particulate phase. During the ISS mission, six samples with a relatively high green density of 65%TD have successfully been processed. The influence of the composition on the combustion process will be examined

Low-gravity combustion synthesis: Theoretical analysis of experimental evidences

The results obtained during a parabolic flight campaign sponsored by ESA on March 2002, and related to the combustion synthesis of TiB2 - xTiAl and TiB2 - xTiAl3 composites are reported. Besides classical SHS experiments performed using cylindrical pellets, combustion front quenching experiments using conical samples placed inside a copper block are also conducted. Similar experiments are carried out under terrestrial conditions, for the sake of comparison. As expected, under both low-gravity and terrestrial conditions, it is found that combustion temperature and front propagation velocity decrease as the system exothermicity is reduced, that is, when the aluminide/diboride molar ratio is augmented. However, it is observed that reaction front propagates relatively slower under low-gravity conditions. Consistently, the extinction of the combustion front occurs earlier when the reaction is performed under reduced gravity conditions. A theoretical analysis performed by means of appropriate dimensionless numbers is proposed to provide possible explanations of the main experimental evidences reported in the literature on this subject, including those shown in this work. Specifically, this analysis reveals that the relatively higher-propagation velocity observed under terrestrial conditions may be due to the correspondingly lower-sample porosity change, which in turn limits the thermal conductivity decreasing in the reaction zone. In addition, free convection phenomena taking place in the molten phase formed at the reaction zone are able to justify the difference in combustion wave velocity experimentally observed under terrestrial conditions between top and bottom ignition configurations. Moreover, it is found that finer microstructure typically observed under low-gravity is likely a consequence of the reduced coalescence phenomena taking place in such conditions

Premature Ovarian Failure and Fertility in Long-Term Survivors of Hodgkin's Lymphoma: A European Organisation for Research and Treatment of Cancer Lymphoma Group and Groupe d'Etude des Lymphomes de l'Adulte Cohort Study

Purpose In this large cohort of Hodgkin's lymphoma survivors with long follow-up, we estimated the impact of treatment regimens on premature ovarian failure (POF) occurrence and motherhood, including safety of nonalkylating chemotherapy and dose-response relationships for alkylating chemotherapy and age at treatment. Patients and Methods The Life Situation Questionnaire was sent to 1,700 women treated in European Organisation for Research and Treatment of Cancer and Groupe d'Etude des Lymphomes de l'Adulte trials between 1964 and 2004. Women treated between ages 15 and 40 years and currently not using hormonal contraceptives (n = 460) were selected to assess occurrence of POF. Cumulative POF risk was estimated using the life-table method. Predictive factors were assessed by Cox regression analysis. Results Median follow-up was 16 years (range, 5 to 45 years). Cumulative risk of POF after alkylating chemotherapy was 60% (95% CI, 41% to 79%) and only 3% (95% CI, 1% to 7%) after nonalkylating chemotherapy (doxorubicin, bleomycin, vinblastine, and dacarbazine; epirubicin, bleomycin, vinblastine, and prednisone). Dose relationship between alkylating chemotherapy and POF occurrence was linear. POF risk increased by 23% per year of age at treatment. In women treated without alkylating chemotherapy at age Conclusion Nonalkylating chemotherapy carries little to no excess risk of POF. Dose-response relationships for alkylating chemotherapy and age at treatment are both linear. Timely family planning is important for women at risk of POF

Parenthood in Survivors of Hodgkin Lymphoma: An EORTC-GELA General Population Case-Control Study

Purpose We investigated the impact of Hodgkin lymphoma (HL) on parenthood, including factors influencing parenthood probability, by comparing long-term HL survivors with matched general population controls. Patients and Methods A Life Situation Questionnaire was sent to 3,604 survivors treated from 1964 to 2004 in successive clinical trials. Responders were matched with controls (1: 3 or 4) for sex, country, education, and year of birth (10-year groups). Controls were given an artificial date of start of treatment equal to that of their matched case. The main end point was presence of biologic children after treatment, which was evaluated by using conditional logistic regression analysis. Logistic regression analysis w Results In all, 1,654 French and Dutch survivors were matched with 6,414 controls. Median follow-up was 14 years (range, 5 to 44 years). After treatment, the odds ratio (OR) for having children was 0.77 (95% CI, 0.68 to 0.87; P < .001) for survivors compared with controls. Of 898 survivors who were childless before treatment, 46.7% achieved post-treatment parenthood compared with 49.3% of 3,196 childless controls (OR, 0.87; P = .08). Among 756 survivors with children before treatment, 12.4% became paren Conclusion Survivors of HL had slightly but significantly fewer children after treatment than matched general population controls. The difference concerned only survivors who had children before treatment and appears to have more personal than biologic reasons. The chance of successful post-treatment parenthood was 76%. J Clin Oncol 30: 3854-3863. (C) 2012 by American Society of Clinical Oncolog

Premature ovarian failure and fertility in long-term survivors of Hodgkin's lymphoma: A European Organisation for Research and Treatment of Cancer Lymphoma Group and Groupe d'ÉTude des Lymphomes de l'Adulte Cohort Study

Purpose: In this large cohort of Hodgkin's lymphoma survivors with long follow-up, we estimated the impact of treatment regimens on premature ovarian failure (POF) occurrence and motherhood, including safety of nonalkylating chemotherapy and dose-response relationships for alkylating chemotherapy and age at treatment. Patients and Methods: The Life Situation Questionnaire was sent to 1,700 women treated in European Organisation for Research and Treatment of Cancer and Groupe d'Étude des Lymphomes de l'Adulte trials between 1964 and 2004. Women treated between ages 15 and 40 years and currently not using hormonal contraceptives (n = 460) were selected to assess occurrence of POF. Cumulative POF risk was estimated using the life-table method. Predictive factors were assessed by Cox regression analysis. Results: Median follow-up was 16 years (range, 5 to 45 years). Cumulative risk of POF after alkylating chemotherapy was 60% (95% CI, 41% to 79%) and only 3% (95% CI, 1% to 7%) after nonalkylating chemotherapy (doxorubicin, bleomycin, vinblastine, and dacarbazine; epirubicin, bleomycin, vinblastine, and prednisone). Dose relationship between alkylating chemotherapy and POF occurrence was linear. POF risk increased by 23% per year of age at treatment. In women treated without alkylating chemotherapy at age younger than 32 years and age 32 years or older, cumulative POF risks were 3% (95% CI, 1% to 16%) and 9% (95% CI, 4% to 18%), respectively. If menstruation returned after treatment, cumulative POF risk was independent of age at treatment. Among women who ultimately developed POF, 22% had one or more children after treatment, compared with 41% of women without POF. Conclusion: Nonalkylating chemotherapy carries little to no excess risk of POF. Dose-response relationships for alkylating chemotherapy and age at treatment are both linear. Timely family planning is important for women at risk of POF