Traditionally, skin involvement in chronic myelomonocytic leukemia (CMML) has been considered to be either specific (leukemia cutis) or non‐specific, with granulomatous dermatitis included in the ...latter group. More recently, the true nature of the myeloid cells present in the cutaneous infiltrates of this theoretically reactive dermatitis is being clarified with the use of new molecular techniques such as next‐generation sequencing. The same mutations in bone marrow (BM) myeloid neoplastic cells and in the cells of cutaneous infiltrates have been found. We present the case of a 77‐year‐old man who presented with spread and treatment‐resistant skin granulomatous lesions previous to the diagnosis of CMML. The same clonal mutations in SRSF2, IDH1, and RUNX1 were found in both skin and BM with resolution of the lesions after the initiation of azacytidine. In conclusion, we report an exceptional case in which specific granulomatous cutaneous lesions have preceded and allowed the earlier diagnosis of an underlying CMML and a review of all previous similar cases in the literature, including molecular alterations.
•Theoretical calculations have been carried out to study FeRh multilayers on MgO(0 0 1).•The out-of-plane relaxation depends on the thickness film and magnetic coupling.•Residual ferromagnetism in ...the interfaces FeRh/MgO(0 0 1) for films -Fe terminated.•The results obtained are mostly influenced by the surface termination (-Rh or -Fe).•The adhesion energy tends to an average value.•The AFM coupling facilitates the takeoff compared to FM coupling.
Low dimensional films are materials of interest for the changes of the structural, electronic and magnetic properties they undergo, especially when they form interfaces with a substrate. The iron-rhodium (FeRh) alloy is an excellent example. Experimentally, FeRh films are deposited on single crystal substrates like MgO, sapphire or silicon. Particularly, MgO (0 0 1) is an excellent support for FeRh because it is possible to deposit high quality epitaxial films on it. MgO is also highly stable at high temperatures and tensile in-plane strain favors the FM over the AFM state.
In order to improve the knowledge of the supported bimetallic systems properties, theoretical calculations using density functional theory (DFT) have been carried out. The different thicknesses considered for the multilayers are 0.6 nm, 0.9 nm and 1.2 nm for both, terminated in Fe or Rh. To complete the study, we present the results obtained on the influence of the termination of the surfaces, the number of alloy layers, the different magnetic configurations (FM – AFM), the charge transfer and the adhesion of the films to the MgO substrate.
The analysis of the results shows that as the thickness of the film grows, the adhesion energy tends to an average value of the order of 1.5 J/m2; on the other hand, the AFM coupling facilitates the takeoff compared to the FM coupling. Moreover, comparing the difference between FM and AFM results for different thicknesses, the percentages are slightly lower for.
–Rh terminated films.
Regarding the out-of-plane relaxation percentages, they depend on the thickness of the film and the magnetic coupling. For the AFM coupling of films -Rh terminated, lower values are observed compared to those obtained for the FM coupling and this behavior is maintained for all three thicknesses studied. However, for the -Fe terminated films as the film grows the relaxations are practically twice those corresponding to the cases of films terminated in Rh tending to tetragonal structures.
With respect to magnetic properties, in the three presented systems for -Rh terminated multilayers, the tendency of magnetic moments values for the FM coupling is maintained in around 3.2 μB/at for the case of Fe and 1.0 μB/at for the case of Rh. For AFM the most noticeable difference is the cancellation of the magnetic moments of Rh. However, the situation is different for the Fe atoms in the -Fe terminated multilayers. For 0.9 nm the Fe atoms in contact with the substrate undergo the least relaxation and their magnetic moments are parallel and equal to −1 μB/at. The Fe atoms of the other layers recovered their values of ±3 μB/at. But when the film grows the Rh atoms acquire a small magnetization in increasing order as it approaches to the free surface. The presence of residual ferromagnetism in the interfaces of the FeRh films deposited on MgO (0 0 1) has also been observed experimentally by other groups. In summary, we can conclude that the obtained results are mostly influenced by the surface termination.
(-Rh or -Fe).
FeRh alloys doped with the third element exhibit a change in the lattice and magnetic subsystems, which are manifested in antiferromagnetic- ferromagnetic (AFM-FM) first-order phase transition ...temperature, the shrinkage of the temperate hysteresis under transition, and the reduction of the saturation magnetization. All aforementioned parameters are crucial for practical applications. To control them it is quite important to determine the driving forces of the metamagnetic transition and its origins. In this manuscript ab initio calculations and experimental studies results are presented, which demonstrate the correlation between the structural and magnetic properties of the Fe50Rh50−xPdx alloys. The qualitative analysis of the metamagnetic phase transition driving forces in palladium-doped FeRh alloys was performed to determine their contribution to the evolution of magnetic and lattice subsystems. In addition, the impact of the impurities phases together with its magnetic behavior on the AFM-FM phase transition was considered.
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•Calculations and EXAFS results revealed a tendency towards tetragonalization of the crystal lattice under doping Pd atoms.•Increase in the interatomic distance between the nearest neighbors of Pd leads to a decrease in Fe atom magnetic moment.•Change in the spin subsystem energy origins a decrease in the phonon energy necessary to initiate a phase transition.•The impact of the γ-phase presence together with its magnetic behavior on the phase transition was studied.•A decrease of the γ-phase volume fraction with Pd content increase was experimentally observed.
•Theoretical calculations have been carried out to study ultrathin FeRh films.•The results obtained are mostly influenced by the surface termination (-Rh or -Fe).•The surface energy follow the ...relationship σ110 < σ001 < σ111.•FeRh(001) and FeRh(110) surfaces are energetically favored respect to FeRh(111).•Rh improves some properties when the number of layers is less than that of Fe.•In almost all studied configurations, the AFM coupling is more stable than the FM.
In this work, the structural, magnetic and energetic properties of ultrathin FeRh films grown in different crystallographic planes, namely (100), (110) and (111), are investigated by using density functional theory calculations. Different thicknesses, atom terminations and magnetic phases (FM and AFM) have been considered. The conclusions differ depending on the direction of growth. In general, values regarding surface energy follow the relationship σ110 < σ001 < σ111 where they grow with increasing thickness, the Rh-terminated surfaces also have higher values with respect to the Fe-terminated ones. Regarding stability, FeRh(001) and FeRh(110) surfaces have similar energy per atom values and are favoured with respect to FeRh(111). In relation to the study of the normal relaxations to surfaces from the thirteen systems, it could be concluded that except for the FeRh(111) surface where contractions between the layers are noticed regardless of termination and magnetic configuration, the other ones show relaxations. The importance of the magnetic order in the films energy stabilization is also analyzed. In summary, it could be said that in most cases Rh-terminated films present unstable and even unpredictable behaviors depending on the number of layers. This suggests that Rh is important in improving some properties, but only when the number of layers is less than that of Fe. That is, the film construction will depend on the specific interest of the particular application to be used in.
In chloroplasts, thiol-dependent redox regulation is linked to light since the disulfide reductase activity of thioredoxins (Trxs) relies on photo-reduced ferredoxin (Fdx). Furthermore, chloroplasts ...harbor an NADPH-dependent Trx reductase (NTR) with a joint Trx domain, termed NTRC. The activity of these two redox systems is integrated by the redox balance of 2-Cys peroxiredoxin (Prx), which is controlled by NTRC. However, NTRC was proposed to participate in redox regulation of additional targets, prompting inquiry into whether the function of NTRC depends on its capacity to maintain the redox balance of 2-Cys Prxs or by direct redox interaction with chloroplast enzymes. To answer this, we studied the functional relationship of NTRC and 2-Cys Prxs by a comparative analysis of the triple Arabidopsis (Arabidopsis thaliana) mutant, ntrc-2cpab, which lacks NTRC and 2-Cys Prxs, and the double mutant 2cpab, which lacks 2-Cys Prxs. These mutants exhibit almost indistinguishable phenotypes: in growth rate, photosynthesis performance, and redox regulation of chloroplast enzymes in response to light and darkness. These results suggest that the most relevant function of NTRC is in controlling the redox balance of 2-Cys Prxs. A comparative transcriptomics analysis confirmed the phenotypic similarity of the two mutants and suggested that the NTRC-2-Cys Prxs system participates in cytosolic protein quality control. We propose that NTRC and 2-Cys Prxs constitute a redox relay, exclusive to photosynthetic organisms that fine-tunes the redox state of chloroplast enzymes in response to light and affects transduction pathways towards the cytosol.
•Fe50Rh50-xPdx (x = 1.9, 3.7, 5.6, 6.3, 7.4, 9.3, 12.5, 18.8, 25.0) has been theoretically studied.•Two AFM configurations (cubic and tetragonal) have been evaluated.•Transition AFM to FM is ...accompanied by increase in volume and decrease in resistivity.•The calculated transition temperature decreases as the Pd content increases.•Total magnetization of the cell/at tends to decrease as x increases.
In this work, spin polarized total energy calculations were carried out to investigate the structural, energetic, magnetic and thermoelectric properties of Fe50Rh50-xPdx (x = 1.9, 3.7, 5.6, 6.3, 7.4, 9.3, 12.5, 18.8 and 25.0) and to compare with previous results of two-component undoped alloy. Some electronic characteristics were evaluated computing the local density of orbital states (LDOS). The corresponding magnetic moments per atom as well as thermal and electrical conductivity were obtained to complete the analysis.
We have found that in the range of Pd concentrations studied, the cell parameter for the FM phase increases slightly as × increases with increasing cell volume (0.2–1.9%). The structures are B2 type. As × increases the AFM phase is more stable than the FM. Concerning the AFM phase, the tetragonal distortion along the z-axis is accompanied by a slight stabilization of the total energy with respect to the cubic phase. The cell volume of the AFM phase is less than that corresponding to the FM phase (varying ~ 0.4 considering the cubic and ~ 0.9 considering the tetragonal). The transition temperature was estimated and the trend agrees with the experimental evidence that the increase of Pd content shifts the transition temperature at lower temperatures. From the DOS (EF) we have also estimated the entropy change (ΔSe) obtaining values ranging from 1 to 9 J/molK depending on the Pd content. Another consequence of the magnetic transition is the drop of the resistivity (ρ) in the FM phase compared to the AFM state in the studied range from 100 K to 300 K. These results agree with literature experimental data.
The redox couple formed by NADPH-dependent thioredoxin reductase C (NTRC) and 2-Cys peroxiredoxins (Prxs) allows fine-tuning chloroplast performance in response to light intensity changes. ...Accordingly, the Arabidopsis 2cpab mutant lacking 2-Cys Prxs shows growth inhibition and sensitivity to light stress. However, this mutant also shows defective post-germinative growth, suggesting a relevant role of plastid redox systems in seed development, which is so far unknown. To address this issue, we first analyzed the pattern of expression of NTRC and 2-Cys Prxs in developing seeds. Transgenic lines expressing GFP fusions of these proteins showed their expression in developing embryos, which was low at the globular stage and increased at heart and torpedo stages, coincident with embryo chloroplast differentiation, and confirmed the plastid localization of these enzymes. The 2cpab mutant produced white and abortive seeds, which contained lower and altered composition of fatty acids, thus showing the relevance of 2-Cys Prxs in embryogenesis. Most embryos of white and abortive seeds of the 2cpab mutant were arrested at heart and torpedo stages of embryogenesis suggesting an essential function of 2-Cys Prxs in embryo chloroplast differentiation. This phenotype was not recovered by a mutant version of 2-Cys Prx A replacing the peroxidatic Cys by Ser. Neither the lack nor the overexpression of NTRC had any effect on seed development indicating that the function of 2-Cys Prxs at these early stages of development is independent of NTRC, in clear contrast with the operation of these regulatory redox systems in leaves chloroplasts.
•Plastid redox systems play an important role in early plant development.•2-Cys peroxiredoxins are detected as aggregates and may have chaperone activity in embryo plastids.•The lack of 2-Cys peroxiredoxins impairs seed development and delays embryogenesis.•The function of 2-Cys peroxiredoxins in embryogenesis is independent of the NTRC redox pathway.
Ab initio study of FeRh alloy properties Jiménez, M. Julia; Schvval, Ana B.; Cabeza, Gabriela F.
Computational materials science,
02/2020, Letnik:
172
Journal Article
Recenzirano
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•Structural, magnetic, thermodynamic and thermoelectric properties have been studied.•Transition from AFM to FM is accompanied by increase in the volume and the Fe mm.•Stability of ...AFM orthorhombic configurations was corroborated with MD simulations.•The changes of entropy (ΔS) involved in the AFM-FM transition have been evaluated.•AFM-B configuration is the most favorable for the metamagnetic phase transition.
In this work the structural, energetic, thermodynamic, magnetic and thermoelectric properties of FeRh alloy have been studied using first-principles calculations. The structural and magnetic results obtained for the FM phase are in agreement with experimental and other theoretical calculated values (local magnetization of about 3 μB and 1 μB for Fe and Rh atoms respectively). The transition AFM to the FM state is accompanied by a 2.4% increase in the volume of the cell and by 9.6% in the Fe spin magnetic moment. The characterization of the AFM phase shows a distortion of the cubic and tetragonal cell to the orthorhombic solving the instabilities observed in the phonon band structures curves of the corresponding to cubic structure. The stability of the AFM configurations was corroborated with molecular dynamics (MD) simulations. The magnitude of the Seebeck coefficient increases with the temperature at a certain chemical potential. While the magnitude of the electrical conductivity does not present meaningful changes with the temperature in the selected values, the thermal conductivity increases with the temperature. Another consequence of the AFM to FM transition is the drop of the resistivity ρ in the FM phase as compared to the AFM state. Based on the results obtained using MD simulations from stable AFM configurations and the results of entropy changes, the configuration AFM-B (type I) could be identified as the most favorable in achieving the metamagnetic phase transition.
•Cost-effective solution for synthesis of utility systems considering all features of steam operating conditions.•Steam sensible heat has been included to provide more realistic and accurate energy ...targets.•The nonconvex MINLP is solved using a solution pool based bilevel decomposition algorithm.•An accurate MINLP and an MILP model are proposed and compared.•Improvement in quality and CPU time over state-of-the-art MINLP solver.•New framework to screen different conversion technologies considering multiple heating levels.
Energy transition to a more sustainable basis is the most significant and complex challenge facing industry. On most industrial sites, the largest single energy user is the utility system that produces the heat and power necessary for the site. The heavy reliance of current utility systems on fossil fuels and the requirement of strategic measures to ensure a sustainable future has prompted researchers to explore different energy sources, technologies and pathways for evolving existing systems to a sustainable basis for future utility systems. Whether based on renewable or non-renewable energy sources, it is essential to minimize energy demand and mitigate emissions. The present work focuses on developing cost-effective solutions for the synthesis of process utility systems, considering site-wide energy integration. This will provide a platform in future work for the efficient introduction of renewable energy sources in the transition to sustainable systems. Utility system performance is generally determined by system configuration and operational load. Steam mains selection, in terms of pressures and superheating have a critical role in the utility system performance and site energy integration. Therefore, the synthesis of energy-efficient utility systems involves optimizing the configuration of utility components and number and operating conditions of steam mains simultaneously. Due to nonlinearities and non-convexities from underlying physics and binary decisions involved, the resulting Mixed-Integer Non-Linear Problem (MINLP) presents challenges for advanced state-of-art solvers to solve real-world problems. In past work, a number of important practical issues have been oversimplified in order to make the solution tractable. However, the oversimplifications also lead to misleading results. In this research, a mathematical formulation for simultaneous optimization of comprehensive utility system configurations and operating conditions is for the first time combined with more realistic steam system configurations and operating conditions to represent the utility systems. Its framework is constructed via a bilevel decomposition algorithm based on piecewise MILP relaxation, McCormick relaxation, and linearization of steam properties. In addition, the solution pool feature of the CPLEX solver is incorporated to enhance the performance and convergence of the algorithm. This work presents the fundamental problem formulation that has not been sufficiently addressed previously. Indeed, this methodology sets out the basis for synthesizing energy-efficient utility systems for the future and allows for many energy conversion technologies and sources to be added to the framework that have previously not been possible to include.
•The optimization model includes more realistic conditions for steam generation and use.•Steam main pressure and superheating temperatures are used as design variables.•A more cost-effective and ...practical design of industrial utility systems can be achieved.•The influence of both number of steam mains and operating conditions is analyzed.•Illustrative case studies demonstrate fuel savings between 15.8 and 32.2%.
Moving industrial production to a more sustainable basis requires a step change in the efficiency of site steam and cogeneration systems, coupled with a switch away from fossil fuels to renewable energy sources. This paper presents the first step in the development of an optimization framework capable of identifying a roadmap to move utility systems to a more sustainable basis. Previous approaches to the design and optimization of steam and cogeneration systems have simplified the problem to the extent that many important practical issues have been neglected, restricting the scope of the options included. The use of grossly simplified models has been prompted by the mathematical difficulties of optimizing such complex energy systems. To overcome limitations in previous work and provide a sound basis for future developments, this paper proposes a new superstructure-based optimization model for the optimization of utility systems, accounting for optimum steam level placement. The latter is important for improving systems efficiency and reducing energy consumption. The optimization problem involves the selection of more realistic operating conditions of the steam mains (superheat conditions and pressure). The model accounts for water preheating, as well as superheating and de-superheating for process steam generation and use. Hot oil circuits are also included as hot utility option to overcome potential steam temperature and/or pressure limitations at high temperatures, and with it provide more flexibility in the framework. The general problem requires making several continuous and discrete decisions, where non-linearities and non-convexities from underlying physics and binary decisions exacerbate the complex nature of the problem, yielding a nonconvex Mixed Integer Non-Linear Programming (MINLP) formulation. However, MINLP formulations can become computationally intractable to solve. Thus, to guarantee tractability and fast conversion, the STYLE model develops a novel successive Mixed Integer Linear Programming formulation. The STYLE methodology is applied to two case studies to illustrate the advantages of the synthesis method and the benefits of optimizing steam levels for the reduction of overall energy consumption at industrial sites. The proposed approach addresses major shortcomings inherent in previous research and provides a foundation for future work to explore the next generation of sustainable utility systems.
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