9 research outputs found
Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017
Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe
Effect of temperature on the growth of single crystalline monolayer graphene by Chemical Vapor Deposition (CVD)
Resumen del póster presentado a la 6th edition of Graphene Conference series, the largest European Event in Graphene and 2D Materials, celebrada en Genova (Italia) del 19 al 22 de abril de 2016.The ever increasing interest in graphene properties and its applications has motivated the controlled growth of high-quality graphene and fabrication of graphene-based devices. The growth of graphene via CVD using metal catalysts depends on both the intrinsic properties of the metal catalysts and the growth parameters. Here we demonstrate that the structure of single layer graphene flakes grown on a copper substrate by low pressure CVD depends dramatically on the furnace temperature, within a few tens of degrees Celsius. Optical microscope analysis of as-grown and transferred graphene onto SiO2/Si shows that growth at 1000ºC results in dendritic shapes while growth at 1040ºC gives a compact graphene flake. The low temperature growth was extended over a long time (1 hour) in order to check if there was a change in the structure towards a compact flake as the one in Figure b, which was obtained after just 10 minutes of growth time at 1040ºC. However, the size of the dendrites increased without merging. Although still poorly understood, the dendritic growth may be due
to the poor smoothening of the copper at the lower annealing temperatures and to the low carbon attachment/detachment kinetics at the graphene growth fronts. We have characterized the charge and spin transport properties of the graphene grown at low
temperatures. We have fabricated non-local spin valve devices with 3 μm graphene channel length and found a spin life time of 0.2 ns and spin diffusion length of 2.5 μm at room temperature. The mobility of the device was of 1000 cm2 /Vs, which is typical for CVD grown graphene on SiO2/Si. Future work will focus on comparing these results with the spintronic performance of graphene grown at higher temperatures.Peer Reviewe
Impact of the in situ rise in hydrogen partial pressure on graphene shape evolution during CVD growth of graphene
Exposing graphene to a hydrogen post-etching process yields dendritic graphene shapes. Here, we demonstrate that similar dendritic structures can be achieved at long growth times without adding hydrogen externally. These shapes are not a result of a surface diffusion controlled growth but of the competing backward reaction (etching), which dominates the growth dynamics at long times due to an in situ rise in the hydrogen partial pressure. We have performed a systematic study on the growth of graphene as a function of time to identify the onset and gradual evolution of graphene shapes caused by etching and then demonstrated that the etching can be stopped by reducing the flow of hydrogen from the feed. In addition, we have found that the etching rate due to the in situ rise in hydrogen is strongly dependent on the confinement (geometrical confinement) of copper foil. Highly etched graphene with dendritic shapes was observed in unconfined copper foil regions while no etching was found in graphene grown in a confined reaction region. This highlights the effect of the dynamic reactant distribution in activating the in situ etching process during growth, which needs to be counteracted or controlled for large scale growth.This research was partially supported by the Spanish Ministry of Economy and Competitiveness, MINECO (under Contracts No. MAT2013-46785-P, No. MAT2016-75952-R, No. MAT2015-68307-
P and Severo Ochoa No. SEV-2013-0295), by the European Research Council under Grant Agreement No. 306652 SPINBOUND, by the European Union's Horizon 2020 research and
innovation programme under grant agreement No. 696656, and by the CERCA Programme and the Secretariat for Universities and Research, Knowledge Department of the Generalitat de
Catalunya 2014 SGR 56. ZMG acknowledges support from MINECO FPI fellowship under Contract No. BES-2014-069925.Peer reviewe
Impact of the in situ rise in hydrogen partial pressure on graphene shape evolution during CVD growth of graphene
Growth to etching transformation following in situ rise in hydrogen with time results in dendritic graphene. Exposing graphene to a hydrogen post-etching process yields dendritic graphene shapes. Here, we demonstrate that similar dendritic structures can be achieved at long growth times without adding hydrogen externally. These shapes are not a result of a surface diffusion controlled growth but of the competing backward reaction (etching), which dominates the growth dynamics at long times due to an in situ rise in the hydrogen partial pressure. We have performed a systematic study on the growth of graphene as a function of time to identify the onset and gradual evolution of graphene shapes caused by etching and then demonstrated that the etching can be stopped by reducing the flow of hydrogen from the feed. In addition, we have found that the etching rate due to the in situ rise in hydrogen is strongly dependent on the confinement (geometrical confinement) of copper foil. Highly etched graphene with dendritic shapes was observed in unconfined copper foil regions while no etching was found in graphene grown in a confined reaction region. This highlights the effect of the dynamic reactant distribution in activating the in situ etching process during growth, which needs to be counteracted or controlled for large scale growth
Epitaxial graphene/silicon carbide intercalation: a minireview on graphene modulation and unique 2D materials
Intercalation of atomic species through epitaxial graphene on silicon carbide began only a few years following its initial report in 2004. The impact of intercalation on the electronic properties of the graphene is well known; however, the intercalant itself can also exhibit intriguing properties not found in nature. This realization has inspired new interest in epitaxial graphene/silicon carbide (EG/SiC) intercalation, where the scope of the technique extends beyond modulation of graphene properties to the creation of new 2D forms of 3D materials. The mission of this minireview is to provide a concise introduction to EG/SiC intercalation and to demonstrate a simplified approach to EG/SiC intercalation. We summarize the primary techniques used to achieve and characterize EG/SiC intercalation, and show that thermal evaporation-based methods can effectively substitute for more complex synthesis techniques, enabling large-scale intercalation of non-refractory metals and compounds including two-dimensional silver (2D-Ag) and gallium nitride (2D-GaNx).This work was supported in part by the 2D Crystal Consortium National Science Foundation (NSF) Materials Innovation Platform under cooperative agreement DMR-1539916, Northrop Grumman Mission Systems’ University Research Program, the Semiconductor Research Corporation Intel/Global Research Collaboration Fellowship, task 2741.001, a grant from the Air Force Office of Scientific Research, grant number FA-9550-18-1-0347, and the NSF CAREER award 1453924.Peer reviewe