Improved kinetic behaviour of Mg(NH2)2-2LiH doped with nanostructured K-modified-LixTiyOz for hydrogen storage

The system Mg(NH2)2 + 2LiH is considered as an interesting solid-state hydrogen storage material owing to its low thermodynamic stability of ca. 40 kJ/mol H2 and high gravimetric hydrogen capacity of 5.6 wt.%. However, high kinetic barriers lead to slow absorption/desorption rates even at relatively high temperatures (>180 °C). In this work, we investigate the effects of the addition of K-modified LixTiyOz on the absorption/desorption behaviour of the Mg(NH2)2 + 2LiH system. In comparison with the pristine Mg(NH2)2 + 2LiH, the system containing a tiny amount of nanostructured K-modified LixTiyOz shows enhanced absorption/desorption behaviour. The doped material presents a sensibly reduced (∼30 °C) desorption onset temperature, notably shorter hydrogen absorption/desorption times and reversible hydrogen capacity of about 3 wt.% H2 upon cycling. Studies on the absorption/desorption processes and micro/nanostructural characterizations of the Mg(NH2)2 + 2LiH + K-modified LixTiyOz system hint to the fact that the presence of in situ formed nanostructure K2TiO3 is the main responsible for the observed improved kinetic behaviour.Fil: Gizer, Gökhan. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; AlemaniaFil: Puszkiel, Julián Atilio. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; Alemania. Comisión Nacional de Energía Atómica. Centro Atómico Ezeiza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Castro Riglos, Maria Victoria. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; Alemania. Comisión Nacional de Energía Atómica. Centro Atómico Ezeiza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pistidda, Claudio. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; AlemaniaFil: Ramallo Lopez, Jose Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Mizrahi, Martin Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; AlemaniaFil: Santoru, Antonio. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; AlemaniaFil: Gemming, Thomas. IFW Dresden; AlemaniaFil: Tseng, Jo Chi. German Electron Synchrotron; AlemaniaFil: Klassen, Thomas. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; AlemaniaFil: Dornheim, Martin. Max-planck Strasse. Helmholtz-Zentrum Geesthacht GmbH. Institute of Materials Research; Alemani

Review of solid–liquid phase change materials and their encapsulation technologies

Various types of solid–liquid phase change materials (PCMs) have been reviewed for thermal energy storage applications. The review has shown that organic solid–liquid PCMs have much more advantages and capabilities than inorganic PCMs but do possess low thermal conductivity and density as well as being flammable. Inorganic PCMs possess higher heat storage capacities and conductivities, cheaper and readily available as well as being non-flammable, but do experience supercooling and phase segregation problems during phase change process. The review has also shown that eutectic PCMs have unique advantage since their melting points can be adjusted. In addition, they have relatively high thermal conductivity and density but they possess low latent and specific heat capacities. Encapsulation technologies and shell materials have also been examined and limitations established. The morphology of particles was identified as a key influencing factor on the thermal and chemical stability and the mechanical strength of encapsulated PCMs. In general, in-situ polymerization method appears to offer the best technological approach in terms of encapsulation efficiency and structural integrity of core material. There is however the need for the development of enhancement methods and standardization of testing procedures for microencapsulated PCMs

The CAFA challenge reports improved protein function prediction and new functional annotations for hundreds of genes through experimental screens

Background The Critical Assessment of Functional Annotation (CAFA) is an ongoing, global, community-driven effort to evaluate and improve the computational annotation of protein function. Results Here, we report on the results of the third CAFA challenge, CAFA3, that featured an expanded analysis over the previous CAFA rounds, both in terms of volume of data analyzed and the types of analysis performed. In a novel and major new development, computational predictions and assessment goals drove some of the experimental assays, resulting in new functional annotations for more than 1000 genes. Specifically, we performed experimental whole-genome mutation screening in Candida albicans and Pseudomonas aureginosa genomes, which provided us with genome-wide experimental data for genes associated with biofilm formation and motility. We further performed targeted assays on selected genes in Drosophila melanogaster, which we suspected of being involved in long-term memory. Conclusion We conclude that while predictions of the molecular function and biological process annotations have slightly improved over time, those of the cellular component have not. Term-centric prediction of experimental annotations remains equally challenging; although the performance of the top methods is significantly better than the expectations set by baseline methods in C. albicans and D. melanogaster, it leaves considerable room and need for improvement. Finally, we report that the CAFA community now involves a broad range of participants with expertise in bioinformatics, biological experimentation, biocuration, and bio-ontologies, working together to improve functional annotation, computational function prediction, and our ability to manage big data in the era of large experimental screens.Peer reviewe

The CAFA challenge reports improved protein function prediction and new functional annotations for hundreds of genes through experimental screens

Background: The Critical Assessment of Functional Annotation (CAFA) is an ongoing, global, community-driven effort to evaluate and improve the computational annotation of protein function. Results: Here, we report on the results of the third CAFA challenge, CAFA3, that featured an expanded analysis over the previous CAFA rounds, both in terms of volume of data analyzed and the types of analysis performed. In a novel and major new development, computational predictions and assessment goals drove some of the experimental assays, resulting in new functional annotations for more than 1000 genes. Specifically, we performed experimental whole genome mutation screening in Candida albicans and aeruginosa genomes, which provided us with genome-wide experimental data for genes associated with biofilm formation and motility. We further performed targeted assays on selected genes in Drosophila melanogaster, which we suspected of being involved in long-term memory. Conclusion: We conclude that while predictions of the molecular function and biological process annotations have slightly improved over time, those of the cellular component have not. Term-centric prediction of experimental annotations remains equally challenging; although the performance of the top methods is significantly better than the expectations set by baseline methods in C. albicans and D. melanogaster, it leaves considerable room and need for improvement. Finally, we report that the CAFA community now involves a broad range of participants with expertise in bioinformatics, biological experimentation, biocuration, and bio-ontologies, working together to improve functional annotation, computational function prediction, and our ability to manage big data in the era of large experimental screens

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

The CAFA challenge reports improved protein function prediction and new functional annotations for hundreds of genes through experimental screens

BackgroundThe Critical Assessment of Functional Annotation (CAFA) is an ongoing, global, community-driven effort to evaluate and improve the computational annotation of protein function.ResultsHere, we report on the results of the third CAFA challenge, CAFA3, that featured an expanded analysis over the previous CAFA rounds, both in terms of volume of data analyzed and the types of analysis performed. In a novel and major new development, computational predictions and assessment goals drove some of the experimental assays, resulting in new functional annotations for more than 1000 genes. Specifically, we performed experimental whole-genome mutation screening in Candida albicans and Pseudomonas aureginosa genomes, which provided us with genome-wide experimental data for genes associated with biofilm formation and motility. We further performed targeted assays on selected genes in Drosophila melanogaster, which we suspected of being involved in long-term memory.ConclusionWe conclude that while predictions of the molecular function and biological process annotations have slightly improved over time, those of the cellular component have not. Term-centric prediction of experimental annotations remains equally challenging; although the performance of the top methods is significantly better than the expectations set by baseline methods in C. albicans and D. melanogaster, it leaves considerable room and need for improvement. Finally, we report that the CAFA community now involves a broad range of participants with expertise in bioinformatics, biological experimentation, biocuration, and bio-ontologies, working together to improve functional annotation, computational function prediction, and our ability to manage big data in the era of large experimental screens.</p

Microstructure analysis of nanosized materials based on x-ray diffraction study

Die Mikrostrukturstrukturanalyse unter Berücksichtigung von Kristallitgröße und Kristalldefekten ist in der heterogenen Katalyse weit verbreitet. Aktive Katalysatoren können auf Trägern abgeschieden sein, nanoskalig und/oder stark deformiert sein. Solche Eigenschaften erschweren die Mikrostrukturanalyse. Um dennoch die genaue Mikrostruktur solcher Materialien zu erhalten, wurde eine Methodik entwickelt, die auf einer Kombination von lokaler TEM und XRD mit integrierter Linienprofilanalyse basiert. Nanoskaliges ZnO, Au@Kohlenstoff und CuO wurden als Beispiele für die Diskussion von Modellierungsstrategien ausgewählt. Eine physikalische Mischung einer niedrigen Konzentration der aktiven Komponente auf einem amorphen Träger wurde gewählt, um die Nachweisgrenzen der Methode zu untersuchen. Als Anwendungsbeispiel wurde CoFe$_{2}$O$_{4}$ als Ausgangsstoff für die Ammoniak-Zersetzung verwendet. Hierbei wurde die Mikrostruktur- und die Kristallstrukturanalyse von $\it in-situ$ XRD Daten kombiniert.Microstructure analysis, considering size and the crystal defects, is widely conducted to heterogeneous catalysis. The active catalysts can be supported components or nanosized/heavily deformed materials. However, such factors make the microstructure analysis difficult. To obtain accurate microstructure for such materials a methodology is developed based on interplay of local TEM and integral XRD with Whole Powder Pattern Modelling approach. Nanosized ZnO, Au@Carbon and CuO are selected as examples to the discussion of modelling strategies. Next, a physical mixture of low loading complex on amorphous support was studied for the detection limits of XRD. As an application, CoFe$_{2}$O$_{4}$ used as a precursor for ammonia decomposition is conducted to combine the analysis of microstructure and crystal structure by means of $\it in-situ$ XRD. The correlation of microstructure with catalytic performance can then be proposed

In Situ Bulk Observations and Ab Initio Calculations Revealing the Temperature Dependence of Stacking Fault Energy in Fe–Cr–Ni Alloys

The dependence of stacking fault energy ($γ_{SFE}$) on temperature in austenitic Fe–Cr–Ni alloy powders was investigated by in situ high energy synchrotron X-ray diffraction and ab initio calculations in the temperature range from − 45 °C to 450 °C. The X-ray diffraction peak positions were used to determine the stacking fault probability and subsequently the temperature dependence of $γ_{SFE}$. The effect of temperature on the diffraction peak positions was found to be mainly reversible; however, recovery of dislocations occurred above about 200 °C, which also gave an irreversible contribution. Two different ab initio-based models were evaluated with respect to the experimental data. The different predictions of the models can be explained by their respective treatment of the magnetic moments for Cr and Ni, which is critical for the alloy compositions investigated. Ab initio calculations, taking longitudinal spin fluctuations (LSF) into consideration within the quasi-classical phenomenological model, predict a temperature dependence of $γ_{SFE}$ in good agreement with the experimentally evaluated trend of increasing $γ_{SFE}$ with increasing temperature: $|Δγ_{SFE}/ΔT|$=0.05mJm$^{−2}$/K. The temperature effect on $γ_{SFE}$ is similar for all three investigated alloys: Fe–18Cr–15Ni, Fe–18Cr–17Ni, Fe–21Cr–16Ni (wt pct), while their room temperature γSFE are evaluated to be 22, 25, 20 mJ m$^{−2}$, respectively

Cu precipitation-mediated formation of reverted austenite during ageing of a 15–5 PH stainless steel

A Cu precipitation-mediated austenitic transformation during ageing treatment of a 15–5 PH stainless steel is revealed through atom probe tomography, in situ synchrotron X-ray diffraction and computational thermodynamics and kinetics. The austenitic transformation is proposed to occur through the pathway: Cu precipitation at the martensite/retained austenite interfaces or at martensite lath boundaries → partitioning of austenite stabilizing elements towards interfaces of the Cu precipitates → reverted austenite formation