Nanomateriales basados en grafeno y su aplicación en nuevos sistemas de energía

[EN] The outstanding physico-chemical properties of graphene have gained considerable interest of the scientific community in last years due to the wide variety of applications in which this material could be used. In this doctoral thesis new nanomaterials based on graphene has been developed and their uses in fields such as Li-ion batteries, photocatalytic generation of hydrogen and photovoltaics have been studied. It has been shown that grapene oxide can be combined with other layered materials such as hydrotalcites and, after chemical reduction by pyrolysis, it is possible to obtain hybrid materials (metal oxides-reduced graphene oxide) that can be employed as anodes in Li-ion batteries, since they exhibit interesting properties derived from the combination of their components (chapter 3). A new way to prepare iron oxide nanoparticles embedded in a graphenic matrix has been presented, showing that this composite exhibits a high capacity of energy storage and durability when it is used as an anode in Li-ion batteries (chapter 4). It has been demonstrated that, although graphene oxide acts as an active photocatalysts under UV irradiation, this can be sensitized with dyes and, in particular, with ruthenium tris-2,2'-bipiridine, which can provide photoactivity under visible light for the generation of hydrogen from water (chapter 5). A new method to prepare phosphorous doped graphene has been described. This nanomaterial acts as a photocatalyst and, under certain conditions, is able to generate considerable amount of hydrogen from water using a UV-Vis lamp as an irradiation source. The values of hydrogen generation rate obtained are comparable to those of the most active organic heterogeneous photocatalysts described in the state of the art (chapter 6). A new method to prepare a p-n heterojunction has been presented, which is based on the combination of boron doped graphene and nitrogen doped graphene. This heterojunction is able to generate higher photocurrent and photovoltage than the separated semiconductor components (chapter 7).[ES] Las extraordinarias propiedades físico-químicas del grafeno han despertado el interés de la comunidad científica en los últimos años debido a las múltiples aplicaciones en las que se podría usar este material. En esta tesis doctoral se han desarrollado nuevos nanomateriales basados en grafeno y se ha estudiado su uso en campos como las baterías de ion-Li, la producción fotocatalítica de hidrógeno y la fotovoltaica. Se ha demostrado que el óxido de grafeno se puede combinar con otros materiales laminares como las hidrotalcitas y que, tras su reducción química por pirólisis, es posible obtener materiales híbridos (óxidos metálicos/óxido de grafeno reducido) que pueden ser empleados como ánodos en baterías de ion-Li, ya que poseen interesantes propiedades derivadas de la combinación de sus componentes (capítulo 3). Se ha presentado una forma novedosa de preparar nanopartículas de óxido de hierro embebidas en una matriz grafénica, estableciendo que este composite posee una elevada capacidad de almacenamiento de carga y durabilidad cuando es empleado como ánodo en baterías de ion-Li (capítulo 4). Se ha comprobado que, aunque el óxido de grafeno es un fotocatalizador activo con luz ultravioleta, éste se puede sensibilizar con colorantes y, en particular, con rutenio tris-2,2'-bipiridilo, el cual le proporciona fotoactividad frente a la luz visible para la generación de hidrógeno a partir de agua (capítulo 5). Se ha descrito un método novedoso de preparar grafeno dopado con fósforo. Este nanomaterial se comporta como fotocatalizador y bajo ciertas condiciones, es capaz de generar cantidades importantes de hidrógeno a partir de agua utilizando lámpara de UV-Vis, midiéndose valores de velocidad de generación de hidrógeno que son comparables con los de los fotocatalizadores orgánicos heterogéneos más activos descritos en el estado del arte (capítulo 6). Se ha presentado una forma novedosa de preparar una heterounión p-n basada en la combinación de grafeno dopado con boro y grafeno dopado con nitrógeno. Esta heterounión es capaz de generar mayor fotocorriente y fotovoltaje que los componentes semiconductores por separado (capítulo 7).[CA] Les extraordinàries propietats fisico-químiques del grafè han despertat l'interès de la comunitat científica en els últims anys a causa de les múltiples aplicacions en les que es podria fer servir aquest material. En aquesta Tesi doctoral s'han desenvolupat nous nanomaterials basats en grafè i s'ha estudiat el seu ús en camps com les bateries d'ió-Li, la producció fotocatalítica d'hidrogen i la fotovoltaica. S'ha demostrat que l'òxid de grafè es pot combinar amb altres materials laminars com les hidrotalcites i que, després de la seva reducció química per piròlisi, és possible obtenir materials híbrids (òxids metàl¿lics / òxid de grafè reduït) que poden ser utilitzats com ànodes en bateries d'ió-Li, ja que posseeixen interessants propietats derivades de la combinació dels seus components (capítol 3). S'ha presentat una forma nova de preparar nanopartícules d'òxid de ferro embegudes en una matriu grafénica, establint que aquest composite té una elevada capacitat d'emmagatzematge de càrrega i durabilitat quan és utilitzat com a ànode en bateries d'ió-Li (capítol 4). S'ha comprovat que, tot i l'òxid de grafè és un fotocatalitzador actiu amb llum ultraviolada, aquest es pot sensibilitzar amb colorants i, en particular, amb ruteni tris-2,2'-bipiridil, el qual li proporciona fotoactivitat enfront de la llum visible per a la generació d'hidrogen a partir d'aigua (capítol 5). S'ha descrit un mètode nou de preparar grafè dopat amb fòsfor. Aquest nanomaterial es comporta com fotocatalitzador i sota certes condicions, és capaç de generar quantitats importants d'hidrogen a partir d'aigua utilitzant llum d'UV-Vis, mesurant valors de velocitat de generació d'hidrogen que són comparables amb els dels fotocatalitzadors orgànics heterogenis més actius descrits en l'estat de l'art (capítol 6). S'ha presentat una forma nova de preparar una heterounió p-n basada en la combinació de grafè dopat amb bor i grafè dopat amb nitrogen. Aquesta heterounió és capaç de generar major fotocorrent i fotovoltatge que els components semiconductors per separat (capítol 7).Latorre Sánchez, M. (2015). Nanomateriales basados en grafeno y su aplicación en nuevos sistemas de energía [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/54135TESI

Green synthesis of Fe3O4 nanoparticles embedded in a porous carbon matrix and its use as anode material for Li-ion batteries

A scalable and simple process was developed for the preparation of Fe3O4 nanoparticles embedded in carbon using nontoxic and affordable materials. The resulting composite showed a high reversible capacity of 702 mA h g(-1) as anode material in a Li-ion battery after 50 cycles.Latorre Sánchez, M.; Primo Arnau, AM.; García Gómez, H. (2012). Green synthesis of Fe3O4 nanoparticles embedded in a porous carbon matrix and its use as anode material for Li-ion batteries. Journal of Materials Chemistry. 22(40):21373-21375. doi:10.1039/c2jm34978gS21373213752240Aricò, A. S., Bruce, P., Scrosati, B., Tarascon, J.-M., & van Schalkwijk, W. (2005). Nanostructured materials for advanced energy conversion and storage devices. Nature Materials, 4(5), 366-377. doi:10.1038/nmat1368Kang, K. (2006). Electrodes with High Power and High Capacity for Rechargeable Lithium Batteries. Science, 311(5763), 977-980. doi:10.1126/science.1122152Armand, M., & Tarascon, J.-M. (2008). Building better batteries. Nature, 451(7179), 652-657. doi:10.1038/451652aTirado, J. L. (2003). Inorganic materials for the negative electrode of lithium-ion batteries: state-of-the-art and future prospects. Materials Science and Engineering: R: Reports, 40(3), 103-136. doi:10.1016/s0927-796x(02)00125-0Etacheri, V., Marom, R., Elazari, R., Salitra, G., & Aurbach, D. (2011). Challenges in the development of advanced Li-ion batteries: a review. Energy & Environmental Science, 4(9), 3243. doi:10.1039/c1ee01598bPoizot, P., Laruelle, S., Grugeon, S., Dupont, L., & Tarascon, J.-M. (2000). Nano-sized transition-metal oxides as negative-electrode materials for lithium-ion batteries. Nature, 407(6803), 496-499. doi:10.1038/35035045Yu, Y., Chen, C.-H., Shui, J.-L., & Xie, S. (2005). Nickel-Foam-Supported Reticular CoO-Li2O Composite Anode Materials for Lithium Ion Batteries. Angewandte Chemie International Edition, 44(43), 7085-7089. doi:10.1002/anie.200501905Liu, D., Garcia, B. B., Zhang, Q., Guo, Q., Zhang, Y., Sepehri, S., & Cao, G. (2009). Mesoporous Hydrous Manganese Dioxide Nanowall Arrays with Large Lithium Ion Energy Storage Capacities. Advanced Functional Materials, 19(7), 1015-1023. doi:10.1002/adfm.200801515Cabana, J., Monconduit, L., Larcher, D., & Palacín, M. R. (2010). Beyond Intercalation-Based Li-Ion Batteries: The State of the Art and Challenges of Electrode Materials Reacting Through Conversion Reactions. Advanced Materials, 22(35), E170-E192. doi:10.1002/adma.201000717Taberna, P. L., Mitra, S., Poizot, P., Simon, P., & Tarascon, J.-M. (2006). High rate capabilities Fe3O4-based Cu nano-architectured electrodes for lithium-ion battery applications. Nature Materials, 5(7), 567-573. doi:10.1038/nmat1672Ban, C., Wu, Z., Gillaspie, D. T., Chen, L., Yan, Y., Blackburn, J. L., & Dillon, A. C. (2010). Nanostructured Fe3O4/SWNT Electrode: Binder-Free and High-Rate Li-Ion Anode. Advanced Materials, 22(20), E145-E149. doi:10.1002/adma.200904285Zhou, G., Wang, D.-W., Li, F., Zhang, L., Li, N., Wu, Z.-S., … Cheng, H.-M. (2010). Graphene-Wrapped Fe3O4Anode Material with Improved Reversible Capacity and Cyclic Stability for Lithium Ion Batteries. Chemistry of Materials, 22(18), 5306-5313. doi:10.1021/cm101532xZhu, T., Chen, J. S., & Lou, X. W. (David). (2011). Glucose-Assisted One-Pot Synthesis of FeOOH Nanorods and Their Transformation to Fe3O4@Carbon Nanorods for Application in Lithium Ion Batteries. The Journal of Physical Chemistry C, 115(19), 9814-9820. doi:10.1021/jp2013754Liu, H., Wang, G., Wang, J., & Wexler, D. (2008). Magnetite/carbon core-shell nanorods as anode materials for lithium-ion batteries. Electrochemistry Communications, 10(12), 1879-1882. doi:10.1016/j.elecom.2008.09.036He, Y., Huang, L., Cai, J.-S., Zheng, X.-M., & Sun, S.-G. (2010). Structure and electrochemical performance of nanostructured Fe3O4/carbon nanotube composites as anodes for lithium ion batteries. Electrochimica Acta, 55(3), 1140-1144. doi:10.1016/j.electacta.2009.10.014Yang, Z., Shen, J., & Archer, L. A. (2011). An in situ method of creating metal oxide–carbon composites and their application as anode materials for lithium-ion batteries. Journal of Materials Chemistry, 21(30), 11092. doi:10.1039/c1jm10902bZhang, W.-M., Wu, X.-L., Hu, J.-S., Guo, Y.-G., & Wan, L.-J. (2008). Carbon Coated Fe3O4Nanospindles as a Superior Anode Material for Lithium-Ion Batteries. Advanced Functional Materials, 18(24), 3941-3946. doi:10.1002/adfm.200801386Piao, Y., Kim, H. S., Sung, Y.-E., & Hyeon, T. (2010). Facile scalable synthesis of magnetitenanocrystals embedded in carbon matrix as superior anode materials for lithium-ion batteries. Chem. Commun., 46(1), 118-120. doi:10.1039/b920037aZhang, M., Lei, D., Yin, X., Chen, L., Li, Q., Wang, Y., & Wang, T. (2010). Magnetite/graphene composites: microwave irradiation synthesis and enhanced cycling and rate performances for lithium ion batteries. Journal of Materials Chemistry, 20(26), 5538. doi:10.1039/c0jm00638fYoon, T., Chae, C., Sun, Y.-K., Zhao, X., Kung, H. H., & Lee, J. K. (2011). Bottom-up in situ formation of Fe3O4 nanocrystals in a porous carbon foam for lithium-ion battery anodes. Journal of Materials Chemistry, 21(43), 17325. doi:10.1039/c1jm13450gBehera, S. K. (2011). Enhanced rate performance and cyclic stability of Fe3O4–graphene nanocomposites for Li ion battery anodes. Chemical Communications, 47(37), 10371. doi:10.1039/c1cc13218kFundueanu, G., Nastruzzi, C., Carpov, A., Desbrieres, J., & Rinaudo, M. (1999). Physico-chemical characterization of Ca-alginate microparticles produced with different methods. Biomaterials, 20(15), 1427-1435. doi:10.1016/s0142-9612(99)00050-2Davis, T. A., Volesky, B., & Mucci, A. (2003). A review of the biochemistry of heavy metal biosorption by brown algae. Water Research, 37(18), 4311-4330. doi:10.1016/s0043-1354(03)00293-8YAKUPARINODOTCA, M. (2004). Biosorption of Hg2+, Cd2+, and Zn2+ by Ca-alginate and immobilized wood-rotting fungus Funalia trogii. Journal of Hazardous Materials, 109(1-3), 191-199. doi:10.1016/j.jhazmat.2004.03.017Gibaud, A., Xue, J. S., & Dahn, J. R. (1996). A small angle X-ray scattering study of carbons made from pyrolyzed sugar. Carbon, 34(4), 499-503. doi:10.1016/0008-6223(95)00207-3Raymundo-Piñero, E., Leroux, F., & Béguin, F. (2006). A High-Performance Carbon for Supercapacitors Obtained by Carbonization of a Seaweed Biopolymer. Advanced Materials, 18(14), 1877-1882. doi:10.1002/adma.200501905Chen, J. S., Zhang, Y., & Lou, X. W. (David). (2011). One-Pot Synthesis of Uniform Fe3O4 Nanospheres with Carbon Matrix Support for Improved Lithium Storage Capabilities. ACS Applied Materials & Interfaces, 3(9), 3276-3279. doi:10.1021/am201079zBonhomme, F., Lassègues, J. C., & Servant, L. (2001). Raman Spectroelectrochemistry of a Carbon Supercapacitor. Journal of The Electrochemical Society, 148(11), E450. doi:10.1149/1.1409546Sadezky, A., Muckenhuber, H., Grothe, H., Niessner, R., & Pöschl, U. (2005). Raman microspectroscopy of soot and related carbonaceous materials: Spectral analysis and structural information. Carbon, 43(8), 1731-1742. doi:10.1016/j.carbon.2005.02.018Verma, P., Maire, P., & Novák, P. (2010). A review of the features and analyses of the solid electrolyte interphase in Li-ion batteries. Electrochimica Acta, 55(22), 6332-6341. doi:10.1016/j.electacta.2010.05.07

Organic fraction of municipal solid waste for the production of L-lactic acid with high optical purity

The organic fraction of municipal solid waste (OFMSW) is an abundant biowaste with great potential in the bioeconomy model. Previous reports have demonstrated that OFMSW hydrolysates are good substrates for lactic acid (LA) production. However, LA can exist in two enantiomeric forms (L- and D-) and most commercial LA applications require a high enantiomeric purity, typically of the L-isomer. Due to natural occurring bacteria in the waste, a mixture of D- and L-LA can form in the substrate, reducing the final enantiomeric purity of the product and limiting its commercial application. In the research reported in this article, hydrolysates from OFMSW were evaluated for the production L-LA with high enantiomeric purity. Firstly, a pre-treatment with monopolar electrodialysis membranes was implemented to remove the unfavourable D-LA in the hydrolysate. This step allowed the reduction in LA concentration and subsequent fermentations of the hydrolysate resulted in enantiomeric purities over 98%. At the pilot scale, a fermentation of the pre-treated hydrolysate, by B. coagulans A166, resulted in a final LA concentration of 61.1 g L−1 and a yield of 0.94 g g−1. The downstream of the process resulted on a LA recovery of 51.5% and a L-LA optical purity of 98.7%

Assessing the organic fraction of municipal solid wastes for the production of lactic acid

With an estimated yearly production of about 140 Mt in the EU, conventionally, the organic fraction of municipal solid wastes (OFMSW) has been disposed in landfills with negative environmental effects. Nonetheless, the chemical composition of this residue make it a substrate with great bioconversion potential. In this study, OFMSW from Spanish municipal treatment plants, were evaluated for the production of LA. Samples were identified according to the sorting mechanisms employed for their collection in: (A) separately collected, (B) non-separately collected and (C) separately collected+paper/cardboard. Enzymatic hydrolysis was used to produce hydrolysates A, B and C accordingly. Hydrolysate A showed the highest total sugars and glucose content with values of 70 and 55 g·L−1, respectively. Following the characterisation, a screening showed that growth of B. coagulans was possible in all three hydrolysates. Furthermore, lab scale fermentations showed that LA final concentrations could reach around 60 g·L−1, with yields from total sugars of above 0.60 g·g−1. A technical scale fermentation of the hydrolysate A resulted in a final LA concentration of 60.7 g·L−1, a yield of 0.71 g·g−1 with a productivity of 2.68 g·L−1·h−1. Overall, it was estimated that 0.23 g of LA could be produced from one g of dry OFMSW

Innovative preparation of MoS2-graphene heterostructures based on alginate containing (NH4)2MoS4 and their photocatalytic activity for H2 generation

Films and particles of MoS2 on graphene (G) showing synergy for photocatalytic H-2 evolution due to the strong interaction between the two layered components have been obtained by pyrolysis at 900 degrees C under argon flow of ammonium alginate, films or powders, containing variable proportions of (NH4)(2)MoS4. X-ray diffraction shows that under these conditions (NH4)(2)MoS4 decomposes to MoS2, while simultaneously alginate forms few layers G or graphitic carbon residues. Sonication of MoS2-G powders in water produces exfoliation of the material leading to few-layers platelets of MoS2-G heterostructures. MoS2 is considered as an alternative of noble metals for H-2 evolution in dye-sensitized photocatalytic systems. In the present case, MoS2-G heterostructures exhibit more than double photocatalytic activity for H-2 generation than pristine MoS2 particles. (C) 2014 Elsevier Ltd. All rights reserved.Financial support by Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ-2012-32315) and Generalidad Valenciana (Prometeo 2012-13) is gratefully acknowledged. ML-S and IE-A thank the Spanish Ministry for postgraduate scholarships.Latorre Sánchez, M.; Esteve Adell, I.; Primo Arnau, AM.; García Gómez, H. (2015). Innovative preparation of MoS2-graphene heterostructures based on alginate containing (NH4)2MoS4 and their photocatalytic activity for H2 generation. Carbon. 81:587-596. https://doi.org/10.1016/j.carbon.2014.09.093S5875968

Luxación periastragalina medial pura: reporte de casos y revisión bibliográfica

Las luxaciones subastragalinas (periastragalinas) sin fractura asociada son un cuadro poco frecuente. Representan solo el 1% de las luxaciones en el ser humano. Presentamos tres casos de luxaciones mediales puras en pacientes que sufrieron un traumatismo de alta energía. En todos los casos, el tratamiento consistió en la reducción cerrada bajo anestesia y posterior inmovilización; la evolución fue satisfactoria. Las luxaciones subastragalinas requieren de un diagnóstico temprano y una rápida resolución. Con estos casos se quiere demostrar la importancia de la sospecha diagnóstica y el beneficio de un tratamiento precoz y acertado. Nivel de Evidencia: I

A proposal for improving safety in construction projects by strengthening coordinators’ competencies in health and safety issues

The figure of the coordinator in health and safety issues in the construction sector first appeared in our legislation through the incorporation of the European Directives (in our case Royal Decree 1627/97 on the minimum health and safety regulations in construction works), and is viewed differently in different countries of the European Union regarding the way they are hired and their role in the construction industry. Coordinating health and safety issues is also a management process that requires certain competencies that are not only based on technical or professional training, but which, taking account of the work environment, require the use of strategies and tools that are related to experience and personal skills. Through a piece of research that took account of expert opinions in the matter, we have found which competencies need to be possessed by the health and safety coordinator in order to improve the safety in the works they are coordinating. The conclusions of the analyses performed using the appropriate statistical methods (comparing means and multivariate analysis techniques), will enable training programmes to be designed and ensure that the health and safety coordinators selected have the competencies required to carry out their duties

Ciencia de Datos en España

Existe un creciente interés de los ciudadanos en el impacto que tiene la Ciencia de Datos en su vida diaria, principalmente debido a la enorme atención que los medios prestan a temas relacionados con el Big Data o la Inteligencia Artificial. Este interés se traduce en grandes expectativas sobre las potenciales aplicaciones de estas tecnologías, pero también en serias preocupaciones, como el uso de datos personales, los procesos de toma de decisiones dirigidos por máquinas o la desaparición de empleos. Junto a esas preocupaciones, también existe una falta de comprensión pública sobre unas tecnologías aún nuevas y cambiantes. La comunicación de la Ciencia de Datos, y particularmente del Big Data y la Inteligencia Artificial, se lleva a cabo en un momento en que los medios no son los únicos encargados de transmitir información sobre la ciencia, sino que otros actores entran en juego para comunicarse directamente con la sociedad a través de canales digitales, de manera que se hace más necesario garantizar la calidad de los procesos de comunicación científica

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Worldwide comparison of survival from childhood leukaemia for 1995–2009, by subtype, age, and sex (CONCORD-2): a population-based study of individual data for 89 828 children from 198 registries in 53 countries

Background Global inequalities in access to health care are reflected in differences in cancer survival. The CONCORD programme was designed to assess worldwide differences and trends in population-based cancer survival. In this population-based study, we aimed to estimate survival inequalities globally for several subtypes of childhood leukaemia. Methods Cancer registries participating in CONCORD were asked to submit tumour registrations for all children aged 0-14 years who were diagnosed with leukaemia between Jan 1, 1995, and Dec 31, 2009, and followed up until Dec 31, 2009. Haematological malignancies were defined by morphology codes in the International Classification of Diseases for Oncology, third revision. We excluded data from registries from which the data were judged to be less reliable, or included only lymphomas, and data from countries in which data for fewer than ten children were available for analysis. We also excluded records because of a missing date of birth, diagnosis, or last known vital status. We estimated 5-year net survival (ie, the probability of surviving at least 5 years after diagnosis, after controlling for deaths from other causes [background mortality]) for children by calendar period of diagnosis (1995-99, 2000-04, and 2005-09), sex, and age at diagnosis (< 1, 1-4, 5-9, and 10-14 years, inclusive) using appropriate life tables. We estimated age-standardised net survival for international comparison of survival trends for precursor-cell acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML). Findings We analysed data from 89 828 children from 198 registries in 53 countries. During 1995-99, 5-year agestandardised net survival for all lymphoid leukaemias combined ranged from 10.6% (95% CI 3.1-18.2) in the Chinese registries to 86.8% (81.6-92.0) in Austria. International differences in 5-year survival for childhood leukaemia were still large as recently as 2005-09, when age-standardised survival for lymphoid leukaemias ranged from 52.4% (95% CI 42.8-61.9) in Cali, Colombia, to 91.6% (89.5-93.6) in the German registries, and for AML ranged from 33.3% (18.9-47.7) in Bulgaria to 78.2% (72.0-84.3) in German registries. Survival from precursor-cell ALL was very close to that of all lymphoid leukaemias combined, with similar variation. In most countries, survival from AML improved more than survival from ALL between 2000-04 and 2005-09. Survival for each type of leukaemia varied markedly with age: survival was highest for children aged 1-4 and 5-9 years, and lowest for infants (younger than 1 year). There was no systematic difference in survival between boys and girls. Interpretation Global inequalities in survival from childhood leukaemia have narrowed with time but remain very wide for both ALL and AML. These results provide useful information for health policy makers on the effectiveness of health-care systems and for cancer policy makers to reduce inequalities in childhood survival