In situ micropillar deformation of hydrides in Zircaloy-4

Deformation of hydrided Zircaloy-4 has been examined using in situ loading of hydrided micropillars in the scanning electron microscope and using synchrotron X-ray Laue microbeam diffraction. Results suggest that both the matrix and hydride can co-deform, with storage of deformation defects observed within the hydrides, which were twinned. Hydrides placed at the plane of maximum shear stress showed deformation within the hydride packet, whilst packets in other pillars arrested the propagation of shear bands. X-ray Laue peak broadening, prior to deformation, was associated with the precipitation of hydrides, and during deformation plastic rotation and broadening of both the matrix and hydride peaks were observed. Post-mortem TEM of the deformed pillars has indicated a greater density of dislocations associated with the precipitated hydride packets, while the observed broadening of the hydride electron diffraction spots further suggests that plastic strain gradients were induced in the hydrides by compression

Structural and Sequence Analysis of Imelysin-Like Proteins Implicated in Bacterial Iron Uptake

Imelysin-like proteins define a superfamily of bacterial proteins that are likely involved in iron uptake. Members of this superfamily were previously thought to be peptidases and were included in the MEROPS family M75. We determined the first crystal structures of two remotely related, imelysin-like proteins. The Psychrobacter arcticus structure was determined at 2.15 Å resolution and contains the canonical imelysin fold, while higher resolution structures from the gut bacteria Bacteroides ovatus, in two crystal forms (at 1.25 Å and 1.44 Å resolution), have a circularly permuted topology. Both structures are highly similar to each other despite low sequence similarity and circular permutation. The all-helical structure can be divided into two similar four-helix bundle domains. The overall structure and the GxHxxE motif region differ from known HxxE metallopeptidases, suggesting that imelysin-like proteins are not peptidases. A putative functional site is located at the domain interface. We have now organized the known homologous proteins into a superfamily, which can be separated into four families. These families share a similar functional site, but each has family-specific structural and sequence features. These results indicate that imelysin-like proteins have evolved from a common ancestor, and likely have a conserved function

A review of non-destructive testing techniques for the in-situ investigation of fretting fatigue cracks

© 2020 The Authors Fretting fatigue can significantly reduce the life of components, leading to unexpected in-service failures. This phenomenon has been studied for over a century, with significant progress being made during the past decade. There are various methods that have been used to study fretting fatigue cracks in order to gain a greater understanding of the effects of fretting fatigue. Destructive methods are traditionally used to observe fretting fatigue cracks. Although useful in determining crack location, crack length, crack propagation modes, crack path and shape, it is not efficient or reliable for time based measurements. Non-destructive testing has developed in recent years and now in-situ monitoring can be used during testing in order to increase the understanding of fretting fatigue. This paper presents a review of non-destructive testing techniques used in-situ during fretting fatigue testing, which are compared in order to conclude the suitability of each technique. Recent developments in non-destructive techniques that could be also applied for fretting fatigue tests are also discussed, as well as recommendations for future research made

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

Acquired dyslexia and dysgraphia in Chinese

Understanding how the mappings between orthography and phonology in alphabetic languages are learned, represented and processed has been enhanced by the cognitive neuropsychological investigation of patients with acquired reading and writing disorders. During the past decade, this methodology has been extended to understanding reading and writing in Chinese leading to new insights about language processing, dyslexia and dysgraphia. The aim of this paper is to review reports of patients who have acquired dyslexia and acquired dysgraphia in Chinese and describe the functional architecture of the reading and writing system. Our conclusion is that the unique features of Chinese script will determine the symptoms of acquired dyslexia and dysgraphia in Chinese. © 2005 - IOS Press and the authors. All rights reserved.link_to_subscribed_fulltex

3D focused ion beam sectioning of zirconium oxides in Zircaloy-4 for the characterisation of cracking

Sequential 2D sectioning and imaging using a dual-beam focused ion beam and scanning electron microscope has been used to characterise the interconnectivity of cracks in oxide films on Zircaloy-4. Evidence of cracks perpendicular to the metal/oxide interface have been observed in multiple oxides of different thicknesses. Such vertical features are considered critical in the provision of a percolation path between the environment and innermost band of lateral cracks (closest to oxide/environment interface), in between the lateral bands of cracks and between the final band of lateral cracks and the metal/oxide interface. Given the limited occurrence of cracks perpendicular to the metal/oxide interface, localised tensile surface strains have been considered as a potential source of initiation of these cracks

The neuropsychological basis of the Chinese mental lexicon: An ERP study using LORETA

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Photodecomposition of Metal Nitrate and Chloride Compounds Yields Amorphous Metal Oxide Films

UV light is found to trigger the decomposition of MCl_<i>x</i> or M­(NO₃)_<i>x</i> (where M = Fe, Co, Ni, Cu, or Zn) to form uniform, amorphous films of metal oxides. This process does not elevate the temperature of the substrate and thus conformal films can be coated on a range of substrates, including rigid glass and flexible plastic. The formation of the oxide films were confirmed by a combination of powder X-ray diffraction, X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy techniques. Amorphous oxide films of iron, nickel and a combination of iron and nickel demonstrated oxygen evolution reaction electrocatalytic activities commensurate with films of the same compositions prepared by widely used electrodeposition and sputtering methods. These results illuminate a potential route to amorphous oxides at scale using simple metal precursors without vacuum or heat