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| 3. |
- Mortazavi, S. M. J., et al.
(författare)
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Does Exposure of Astronauts' Brains to High-LET Radiation in Deep Space Threaten the Success of the Mission?
- 2020
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Ingår i: 2020 IEEE AEROSPACE CONFERENCE (AEROCONF 2020). - 1095-323X. - 9781728127347
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Konferensbidrag (refereegranskat)abstract
- Astronauts' exposure to radiation is different from exposure to radiation on Earth. Besides cancer, cardiovascular disease and acute radiation syndrome, there are concerns over the potential behavioral and cognitive impairments caused by exposure of the astronauts' central nervous system to high levels of space radiation. Therefore, potential behavioral and cognitive i mpairments caused by astronauts' brains exposure to high levels of space radiation and the possibility of developing dementia and other motor neuron diseases are getting more attention. As NASA is interested in studies on radium deposition in human brain, and exposure of the brain to high linear energy transfer (LET) alpha particles, we have assessed the cognitive effects of long-term exposure of human brain to alpha particles which partly mimics astronauts' exposure to high charge and energy (HZE) particles during upcoming mars missions. Dr. John Boice, President of NCRP, and his colleagues' have stated that human brain exposed for years to alpha particles on Earth may be more relevant to a Mars mission in contrast with the mouse brain exposed to heavy ions for a few minutes. Interestingly, both Boice and NASA did not pay enough attention to this fact that radium as well as many other alpha emitters tend to accumulate in the bone, and the alpha particles whose energies are typically -5 MeV have a very short range (maximum lOs of um), so the radiation dose due to the alpha emitters would be localized to volumes near the cranium rather than being uniformly distributed throughout the cerebral and cerebellar parenchyma. Extraordinary high levels of Ra-226 have previously been reported in high background radiation areas of Ramsar, where people are consuming locally grown foods. In this paper, we will present data which provide a human brain radiation exposure analogue for upcoming Mars missions. Normally the dose to the functional parts of the brain are not likely to be significant, even with higher uptakes of the radium or other alpha-emitting isotopes in the cranium. Therefore, only residents with calcium-rich diet were selected for the study. Measurements of background gamma radiation was performed in their bedrooms, dining rooms, vegetable yards and gardens with citrus fruit trees of the dwellings in areas with high levels of Ra-226 in the soil and at a nearby control area with the same socio-economic factors. Moreover, the food frequency, reaction time, working memory and computational abilities as well as the Radium Ingestion Index (RII) of 47 participants (22 males and 24 females) from the hot areas, where the annual radiation absorbed dose from background radiation is up to 260 mSv/y, were studied, and the same things were studied for 17 participants (4 males and 13 females) from a nearby normal background radiation area with the same socioeconomic factors as at the hot areas. Our study showed that exposure of human brain to high LET particles did not affect the working memory. However, individuals with higher levels of radium ingestion had significantly increased reaction times. The increased reaction time in individuals with higher exposure levels to alpha particles emitted from ingested Ra-226 is an important finding, since similar conditions might occur in deep space, when astronauts' brain cells are exposed to HZE particles. As the astronauts face numerous challenges in isolated and confined space environment, they should be able to respond quickly to different hazards. However, further studies are needed to verify if the fmdings in high radiation dose areas in Ramsar are relevant for deep space mission.
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| 4. |
- Ash, G. I., et al.
(författare)
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Establishing a Global Standard for Wearable Devices in Sport and Exercise Medicine: Perspectives from Academic and Industry Stakeholders
- 2021
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Ingår i: Sports Medicine. - : Springer Science and Business Media LLC. - 0112-1642 .- 1179-2035. ; 51, s. 2237-2250
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Tidskriftsartikel (refereegranskat)abstract
- Millions of consumer sport and fitness wearables (CSFWs) are used worldwide, and millions of datapoints are generated by each device. Moreover, these numbers are rapidly growing, and they contain a heterogeneity of devices, data types, and contexts for data collection. Companies and consumers would benefit from guiding standards on device quality and data formats. To address this growing need, we convened a virtual panel of industry and academic stakeholders, and this manuscript summarizes the outcomes of the discussion. Our objectives were to identify (1) key facilitators of and barriers to participation by CSFW manufacturers in guiding standards and (2) stakeholder priorities. The venues were the Yale Center for Biomedical Data Science Digital Health Monthly Seminar Series (62 participants) and the New England Chapter of the American College of Sports Medicine Annual Meeting (59 participants). In the discussion, stakeholders outlined both facilitators of (e.g., commercial return on investment in device quality, lucrative research partnerships, and transparent and multilevel evaluation of device quality) and barriers (e.g., competitive advantage conflict, lack of flexibility in previously developed devices) to participation in guiding standards. There was general agreement to adopt Keadle et al.'s standard pathway for testing devices (i.e., benchtop, laboratory, field-based, implementation) without consensus on the prioritization of these steps. Overall, there was enthusiasm not to add prescriptive or regulatory steps, but instead create a networking hub that connects companies to consumers and researchers for flexible guidance navigating the heterogeneity, multi-tiered development, dynamicity, and nebulousness of the CSFW field.
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| 5. |
- Lin, Yue, et al.
(författare)
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Expression of interfacial Seebeck coefficient through grain boundary engineering with multi-layer graphene nanoplatelets
- 2020
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Ingår i: Energy & Environmental Science. ; 13, s. 4114-4121
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Tidskriftsartikel (refereegranskat)abstract
- Energy filtering has been a long-sought strategy to enhance a thermoelectric material's figure of merit zT through improving its power factor. Here we show a composite of multi-layer graphene nanoplatelets (GNP) and n-type Mg3Sb2 leads to the expression of an energy filtering like effect demonstrated by an increase in the material's Seebeck coefficient and maximum power factor, without impact on the material's carrier concentration. We analyse these findings from the perspective of a heterogeneous material consisting of grain and grain boundary phases, instead of a more traditional and common analysis that assumes a homogeneously transporting medium. An important implication of this treatment is that it leads to the development of an interfacial Seebeck coefficient term, which can explain the observed increase in the material's Seebeck coefficient. The contribution of this interfacial Seebeck coefficient to the overall Seebeck coefficient is determined by the relative temperature drop across the grain boundary region compared to that of the bulk material. In Te doped Mg3Sb2 we show the introduction of GNP increases the interfacial thermal resistance of grain boundaries, enhancing the contribution of the interfacial Seebeck coefficient arising from grain boundaries to the overall Seebeck coefficient. Without significant detriment to the electrical conductivity this effect results in a net increase in maximum power factor. This increased interfacial thermal resistance also leads to the synergistic reduction of the total thermal conductivity. As a result, we enhance zT of the Mg3Sb2 to a peak value of 1.7 near 750 K. Considering the two-dimensional nature of the grain boundary interface, this grain boundary engineering strategy could be applied to a few thermoelectric systems utilizing various two-dimensional nanomaterials.
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| 8. |
- Smith, P B, et al.
(författare)
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Cultural values, sources of guidance, and their relevance to managerial behavior - A 47-nation study
- 2002
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Ingår i: Journal of Cross-Cultural Psychology. - : Sage Publications. - 0022-0221 .- 1552-5422. ; 33:2, s. 188-208
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Tidskriftsartikel (refereegranskat)abstract
- Data are presented showing how middle managers in 47 countries report handling eight specific work events. The data are used to test the ability of cultural value dimensions derived from the work of Hofstede. Trompenaars, and Schwartz to predict the specific sources of guidance on which managers rely. Focusing on sources of guidance is expected to provide a more precise basis than do generalized measures of values for understanding the behaviors that prevail within different cultures. Values are strongly predictive of reliance on those sources of guidance that are relevant to vertical relationships within organizations. Hock ever, values are less successful in predicting reliance on peers and on more tacit sources of guidance. Explaining national differences in these neglected aspects of organizational processes will require greater sensitivity to the culture-specific contexts within which they occur.
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| 13. |
- Bonora, Nicola, et al.
(författare)
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Numerical Simulation of Dynamic Tensile Extrusion Test of OFHC Copper
- 2015
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Ingår i: Journal of Dynamic Behavior of Materials. - : Springer Science and Business Media LLC. - 2199-7446 .- 2199-7454. ; 1, s. 136-152
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Tidskriftsartikel (refereegranskat)abstract
- The dynamic tensile extrusion (DTE) test offersunique possibility to probe material response under verylarge plastic strain, high strain rate and temperature tosupport constitutive modelling development. From thecomputational point of view, the DTE test is particularlychallenging and a number of issues need to be assessedbefore proceeding with material modelling verification. Inthis work, an extensive and detailed computational workwas carried out in order to provide the guidelines for accuratesimulation of DTE test. Two constitutive models,the first phenomenological the latter physically-based, wereused to simulated the behavior of fully annealed OFHCcopper in dynamic extrusion at different velocities. Materialmodels parameters were calibrated using uniaxial testdata at different strain rates and temperatures. The number,size and shape of the ejected fragments at different velocitywere used as validation metrics for the selected constitutivemodels. Results indicate that material behavior under dynamicextrusion can be accurately predicted limiting theinfluence of numerical parameters not related to the constitutivemodel under investigation. The physically basedmodelling allows a more accurate prediction of the materialresponse and the possibility to incorporate microstructureevolution processes, such as dynamic recrystallization,which seems to control the response of OFHC copper inDTE tests at higher velocity.
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| 14. |
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| 15. |
- Bonora, Nicola, et al.
(författare)
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Validating material modelling for OFHC copper using Dynamic Tensile Extrusion (DTE) test at different velocity impact
- 2017
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Ingår i: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1793, s. 100019-
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Konferensbidrag (refereegranskat)abstract
- In the Dynamic Tensile Extrusion (DTE) test, the material is subjected to very large strain, high strain rate and elevated temperature. Numerical simulation, validated comparing with measurements obtained on soft-recovered extruded fragments, can be used to probe material response under such extreme conditions and to assess constitutive models. In this work, the results of a parametric investigation on the simulation of DTE test of annealed OFHC copper -at impact velocity ranging from 350 up to 420 m/s -using the modified Rusinek-Klepaczko model, are presented. Simulation of microstructure evolution was performed using the visco-plastic self consistent model (VPSC), providing, as input, the velocity gradient history obtained with FEM at selected locations along the axis of the fragment trapped in the extrusion die. Finally, results are compared with EBSD analysis.
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| 16. |
- Esmaily, Mohsen, 1987, et al.
(författare)
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Corrosion behaviour of friction stir-welded AA6005-T6 using a bobbin tool
- 2016
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X. ; 111, s. 98-109
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Tidskriftsartikel (refereegranskat)abstract
- The atmospheric corrosion of extruded AA6005-T6 weldments produced with bobbin friction stir welding (BFSW) using fast and slow process parameters has been analyzed. The weldments of the same material fabricated using conventional FSW were also exposed as reference. Copper-rich phase particles were detected at the grain boundaries in the stir zone of both specimens. It was evident that the BFSW specimens exhibit better corrosion behaviour than the specimens produced using the slow process parameters. An effort was made to carefully attribute the improved corrosion resistance of the fast BFSW specimens to the difference in the microstructure of the weldments. (C) 2016 Elsevier Ltd. All rights reserved.
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| 17. |
- Esmaily, Mohsen, 1987, et al.
(författare)
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Influence of Multi-Pass Friction Stir Processing on the Corrosion Behavior of an Al-Mg-Si Alloy
- 2016
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 163:3, s. C124-C130
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Tidskriftsartikel (refereegranskat)abstract
- The effect of multi-pass (100% overlap) friction stir processing (FSP) on the NaCl-induced atmospheric corrosion behavior of an extruded 6005-T6 aluminum alloy has been studied. Samples were contaminated with 70 and 200 mu g/cm(2) NaCl and exposed in the presence of 400 ppm CO2 for a time interval of 200-3200 h. The results showed that increasing the number of passes gives rise to several crucial changes in the microstructure of the processed regions. Gravimetric analyses and morphological inspections of the corroded samples revealed that multi-pass FSP has also a significant impact on the NaCl-induced atmospheric corrosion behavior of the FS processed samples. While increasing the number of FSP passes resulted in a reduced extent of pitting corrosion in the stir zone, it induced a significant pitting corrosion attack in the heat affected zone of the samples, which were shown to be linked to a reduction in the size of intermetallic particles in the stir zone of the multi-pass FSP specimens. The results also showed that the cathodic activity of intermetallic particles in this family of Al alloys is size-dependent. (C) The Author(s) 2016. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.
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| 18. |
- Gomez-Cabrero, D, et al.
(författare)
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STATegra, a comprehensive multi-omics dataset of B-cell differentiation in mouse
- 2019
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Ingår i: Scientific data. - : Springer Science and Business Media LLC. - 2052-4463. ; 6:1, s. 256-
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Tidskriftsartikel (refereegranskat)abstract
- Multi-omics approaches use a diversity of high-throughput technologies to profile the different molecular layers of living cells. Ideally, the integration of this information should result in comprehensive systems models of cellular physiology and regulation. However, most multi-omics projects still include a limited number of molecular assays and there have been very few multi-omic studies that evaluate dynamic processes such as cellular growth, development and adaptation. Hence, we lack formal analysis methods and comprehensive multi-omics datasets that can be leveraged to develop true multi-layered models for dynamic cellular systems. Here we present the STATegra multi-omics dataset that combines measurements from up to 10 different omics technologies applied to the same biological system, namely the well-studied mouse pre-B-cell differentiation. STATegra includes high-throughput measurements of chromatin structure, gene expression, proteomics and metabolomics, and it is complemented with single-cell data. To our knowledge, the STATegra collection is the most diverse multi-omics dataset describing a dynamic biological system.
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| 19. |
- Hörnqvist Colliander, Magnus, 1979, et al.
(författare)
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Deformation and texture evolution of OFHC copper during dynamic tensile extrusion
- 2015
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454. ; 89, s. 163-180
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Tidskriftsartikel (refereegranskat)abstract
- During dynamic tensile extrusion (DTE) the material is subjected to a complex deformation history, including high strain rates, large strains and elevated temperatures. This technique provides unique means to explore material performance under extreme conditions. In this work, the microstructural evolution of 99.98% commercially pure copper during the DTE test was investigated by means of electron backscatter diffraction (EBSD). The investigation was focused on the segment of the extruded jet that remained in the die, since numerical simulation showed that material points along the longitudinal axis of such segment correspond to different stages of a common temperature compensated deformation history. Therefore, post mortem microstructure information extracted at different locations along the center line is equivalent to in situ real-time measurement during the deformation process. EBSD investigations along the center line showed a progressive elongation of the grains, and an accompanying development of a strong 〈0 0 1〉 + 〈1 1 1〉 dual fiber texture. Meta-dynamic discontinuous dynamic recrystallization (DRX) occurred at larger strains, and it was demonstrated that nucleation occurred during straining, while subsequent grain growth took place during post-deformation cooling in the die. According to strain energy minimization arguments, the recrystallization resulted in an increased 〈0 0 1〉 texture component. The critical strain for recrystallization was well predicted from a power-law dependence on the Zener–Hollomon parameter, including grain size dependence and a temperature dependent activation energy. In addition, it was shown that 〈0 0 1〉 and 〈1 1 1〉oriented grains develop different dislocation substructures during straining, exhibiting elongated cells/micro-bands and typical cell structures, respectively. The present results also confirm that dynamic tensile ductility increases with decreasing initial grain size as a result of grain refinement and lowering of dislocation and twin densities during DRX.
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| 20. |
- Marazioti, Antonia, et al.
(författare)
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KRAS signaling in malignant pleural mesothelioma
- 2022
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4684 .- 1757-4676. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Malignant pleural mesothelioma (MPM) arises from mesothelial cells lining the pleural cavity of asbestos-exposed individuals and rapidly leads to death. MPM harbors loss-of-function mutations in BAP1, NF2, CDKN2A, and TP53, but isolated deletion of these genes alone in mice does not cause MPM and mouse models of the disease are sparse. Here, we show that a proportion of human MPM harbor point mutations, copy number alterations, and overexpression of KRAS with or without TP53 changes. These are likely pathogenic, since ectopic expression of mutant KRASG12D in the pleural mesothelium of conditional mice causes epithelioid MPM and cooperates with TP53 deletion to drive a more aggressive disease form with biphasic features and pleural effusions. Murine MPM cell lines derived from these tumors carry the initiating KRASG12D lesions, secondary Bap1 alterations, and human MPM-like gene expression profiles. Moreover, they are transplantable and actionable by KRAS inhibition. Our results indicate that KRAS alterations alone or in accomplice with TP53 alterations likely play an important and underestimated role in a proportion of patients with MPM, which warrants further exploration.
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| 21. |
- Mortazavi, Susanne E., et al.
(författare)
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Acquisition of complement fixing antibodies targeting Plasmodium falciparum merozoites in infants and their mothers in Uganda
- 2023
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Ingår i: Frontiers in Immunology. - 1664-3224. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Antibody-mediated complement fixation has previously been associated with protection against malaria in naturally acquired immunity. However, the process of early-life development of complement-fixing antibodies in infants, both in comparison to their respective mothers and to other immune parameters, remains less clear. Results: We measured complement-fixing antibodies in newborns and their mothers in a malaria endemic area over 5 years follow-up and found that infants’ complement-fixing antibody levels were highest at birth, decreased until six months, then increased progressively until they were similar to birth at five years. Infants with high levels at birth experienced a faster decay of complement-fixing antibodies but showed similar levels to the low response group of newborns thereafter. No difference was observed in antibody levels between infant cord blood and mothers at delivery. The same result was found when categorized into high and low response groups, indicating placental transfer of antibodies. Complement-fixing antibodies were positively correlated with total schizont-specific IgG and IgM levels in mothers and infants at several time points. At nine months, complement-fixing antibodies were negatively correlated with total B cell frequency and osteopontin concentrations in the infants, while positively correlated with atypical memory B cells and P. falciparum-positive atypical memory B cells. Conclusion: This study indicates that complement-fixing antibodies against P. falciparum merozoites are produced in the mothers and placentally-transferred, and they are acquired in infants over time during the first years of life. Understanding early life immune responses is crucial for developing a functional, long lasting malaria vaccine.
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| 22. |
- Testa, Gabriel, et al.
(författare)
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Modelling and simulation of dynamic recrystallization (DRX) in OFHC copper at very high strain rates
- 2017
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Ingår i: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. - 9780735414570 ; 1793, s. Article number 100034-
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Konferensbidrag (refereegranskat)abstract
- At high strain rates, deformation processes are essentially adiabatic and if the plastic work is large enough dynamic recrystallization can occur. In this work, an examination on microstructure evolution of OFHC copper in Dynamic Tensile Extrusion (DTE) test, performed at 400 m/s, was carried out. EBSD investigations, along the center line of the fragment remaining in the extrusion die, showed a progressive elongation of the grains, and an accompanying development of a strong + dual fiber texture. Discontinuous dynamic recrystallization (DRX) occurred at larger strains, and it was showed that nucleation occurred during straining. A criterion for DRX to occur, based on the evolution of Zener-Hollomon parameter during the dynamic deformation process, is proposed. Finally, DTE test was simulated using the modified Rusinek-Klepaczko constitutive model incorporating a model for the prediction of DRX initiation.
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