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Treatment of head louse infection is primarily through topical insecticides. However, there is growing evidence of resistance. A representative population sample was tested using biochemical and molecular methods; it was shown that, in Wales, treatments containing pyrethroids are likely to be less effective in controlling head louse infection than those containing organophosphates. [ABSTRACT FROM AUTHOR]

The biocompatibility and resorption characteristics of β-tricalcium phosphate (β-TCP, Ca3(PO4)2) have made it a coveted alternative for bone grafts. However, the underlying mechanisms governing the biological interactions between β-tricalcium phosphate and osteoclasts remain elusive. It has been speculated that the composition at grain boundaries might vary and affect β-TCP resorption properties. Atom probe tomography (APT) offers a quantitative approach to assess the composition of the grain boundaries, and thus advance our comprehension of the biological responses within the microstructure and chemical composition at the nanoscale. The precise quantitative analysis of chemical composition remains a notable challenge in APT, primarily due to the influence of measurement conditions on compositional accuracy. In this study, we investigated the impact of laser pulse energy on the composition of β-TCP using APT, aiming for the most precise Ca:P ratio and consistent results across multiple analyses performed with different sets of analysis conditions and on two different instruments., Competing Interests: Conflict of Interest The authors declare that they have no competing interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Microscopy Society of America.)

The early stages of corrosion occurring at liquid-solid interfaces control the evolution of the material's degradation process, yet due to their transient state, their analysis remains a formidable challenge. Here corrosion tests are performed on a MgCa alloy, a candidate material for biodegradable implants using pure water as a model system. The corrosion reaction is suspended by plunge freezing into liquid nitrogen. The evolution of the early-stage corrosion process on the nanoscale by correlating cryo-atom probe tomography (APT) with transmission-electron microscopy (TEM) and spectroscopy, is studied. The outward growth of Mg hydroxide Mg(OH) 2 and the inward growth of an intermediate corrosion layer consisting of hydrloxides of different compositions, mostly monohydroxide Mg(OH) instead of the expected MgO layer, are observed. In addition, Ca partitions to these newly formed hydroxides and oxides. Density-functional theory calculations suggest a domain of stability for this previously experimental unreported Mg(OH) phase. This new approach and these new findings advance the understanding of the early stages of magnesium corrosion, and in general reactions and processes at liquid-solid interfaces, which can further facilitate the development of corrosion-resistant materials or better control of the biodegradation rate of future implants., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Atom probe tomography requires needle-shaped specimens with a diameter typically below 100 nm, making them both very fragile and reactive, and defects (notches at grain boundaries or precipitates) are known to affect the yield and data quality. The use of a conformal coating directly on the sharpened specimen has been proposed to increase yield and reduce background. However, to date, these coatings have been applied ex situ and mostly are not uniform. Here, we report on the controlled focused-ion beam in situ deposition of a thin metal film on specimens immediately after specimen preparation. Different metallic targets e.g. Cr were attached to a micromanipulator via a conventional lift-out method and sputtered using Ga or Xe ions. We showcase the many advantages of coating specimens from metallic to nonmetallic materials. We have identified an increase in data quality and yield, an improvement of the mass resolution, as well as an increase in the effective field-of-view. This wider field-of-view enables visualization of the entire original specimen, allowing to detect the complete surface oxide layer around the specimen. The ease of implementation of the approach makes it very attractive for generalizing its use across a very wide range of atom probe analyses., Competing Interests: Conflict of Interest The authors declare that they have no competing interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Microscopy Society of America.)

In this study, advanced techniques such as atom probe tomography, atomic force microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy were used to determine the corrosion mechanism of the as-ECAPed Zn-0.8Mg-0.2Sr alloy. The influence of microstructural and surface features on the corrosion mechanism was investigated. Despite its significance, the surface composition before exposure is often neglected by the scientific community. The analyses revealed the formation of thin ZnO, MgO, and MgCO 3 layers on the surface of the material before exposure. These layers participated in the formation of corrosion products, leading to the predominant occurrence of hydrozincite. In addition, the layers possessed different resistance to the environment, resulting in localized corrosion attacks. The segregation of Mg on the Zn grain boundaries with lower potential compared with the Zn-matrix was revealed by atom probe tomography and atomic force microscopy. The degradation process was initiated by the activity of micro-galvanic cells, specifically Zn - Mg 2 Zn 11 /SrZn 13 . This process led to the activity of the crevice corrosion mechanism and subsequent attack to a depth of 250 μm. The corrosion rate of the alloy determined by the weight loss method was 0.36 mm·a -1 . Based on this detailed study, the degradation mechanism of the Zn-0.8Mg-0.2Sr alloy is proposed., Competing Interests: None., (© 2023 The Authors.)

In response to the requirements imposed by the COVID-19 pandemic in 2020, we developed a remote learning undergraduate workshop for 44 students at the University of Newcastle by embedding scanning electron microscope (SEM) images of Maratus (Peacock) spiders into the MyScope Explore environment. The workshop session had two main components: 1) to use the online MyScope Explore tool to virtually image scales with structural color and pigmented color on Maratus spiders; 2) to join a live SEM session via Zoom to image an actual Maratus spider. In previous years, the undergraduate university students attending this annual workshop would enter the Microscopy Facility at the University of Newcastle to image specimens with SEM; however, in 2020 the Microscopy Facility was closed to student visitors, and this virtual activity was developed in order to proceed with the educational event. The program was highly successful and constitutes a platform that can be used in the future by universities for teaching microscopy remotely., (© The Author(s), 2021. Published by Cambridge University Press on behalf of the Microscopy Society of America.)

Laser ablation is capable of removing large volumes of material with micron scale precision at very high speeds. This makes it an ideal tool for the initial stage of preparation of samples for atom probe and electron microscopy studies. However, the thermal nature of the laser ablation process is such that thermal and mechanical damage is induced in the samples in the form of zones of recrystallisation and stress induced deformation. For the analysis of nanometer-sized samples, such as those required for atom probe tomography and transmission electron microscopy, it is necessary to ensure that any damage induced during sample preparation will not introduce artefacts and that specimens are representative of the microstructure of the bulk sample. Here we have undertaken an analysis of the damage caused during sample preparation through a study of pure aluminium and phosphorous doped silicon wafers. Our findings indicate that recrystallisation and stress induced misorientations occur in pure aluminium at the micron scale, however, no detectable damage is observed in the silicon sample., (Copyright © 2020. Published by Elsevier B.V.)

There has been a recent surge in the use of cryo and/or vacuum specimen preparation and transfer systems to broaden the scope of research enabled by the microscopy technique of atom probe tomography. This is driven by the fact that, as for many microscopes, the application of atom probes to air- and temperature-sensitive materials or wet biological specimens has previously been limited by transfer through air at room temperature. Here we provide an overview of areas of research that benefit from these new transfer and analysis protocols, as well as a review of current advances in transfer devices, environmental cells, and glove boxes for controlled specimen manipulation. This includes the study of catalysis and corrosion, biological samples, liquid-solid interfaces, natural aging, and the distribution of hydrogen in materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Hydrogen embrittlement of high-strength steel is an obstacle for using these steels in sustainable energy production. Hydrogen embrittlement involves hydrogen-defect interactions at multiple-length scales. However, the challenge of measuring the precise location of hydrogen atoms limits our understanding. Thermal desorption spectroscopy can identify hydrogen retention or trapping, but data cannot be easily linked to the relative contributions of different microstructural features. We used cryo-transfer atom probe tomography to observe hydrogen at specific microstructural features in steels. Direct observation of hydrogen at carbon-rich dislocations and grain boundaries provides validation for embrittlement models. Hydrogen observed at an incoherent interface between niobium carbides and the surrounding steel provides direct evidence that these incoherent boundaries can act as trapping sites. This information is vital for designing embrittlement-resistant steels., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

In this work, we demonstrate a new system for the examination of gas interactions with surfaces via atom probe tomography. This system provides capability of examining the surface and subsurface interactions of gases with a wide range of specimens, as well as a selection of input gas types. This system has been primarily developed to aid the investigation of hydrogen interactions with metallurgical samples, to better understand the phenomenon of hydrogen embrittlement. In its current form, it is able to operate at pressures from 10-6 to 1000 mbar (abs), can use a variety of gasses, and is equipped with heating and cryogenic quenching capabilities. We use this system to examine the interaction of hydrogen with Pd, as well as the interaction of water vapor and oxygen in Mg samples.

Understanding oxide-metal interfaces is crucial to the advancement of materials and components for many industries, most notably for semiconductor devices and power generation. Atom probe tomography provides three-dimensional, atomic scale information about chemical composition, making it an excellent technique for interface analysis. However, difficulties arise when analyzing interfacial regions due to trajectory aberrations, such as local magnification, and reconstruction artifacts. Correlative microscopy and field simulation techniques have revealed that nonuniform evolution of the tip geometry, caused by heterogeneous field evaporation, is partly responsible for these artifacts. Here we attempt to understand these trajectory artifacts through a study of the local evaporation field conditions. With a better understanding of the local evaporation field, it may be possible to account for some of the local magnification effects during the reconstruction process, eliminating these artifacts before data analysis.

Here, we present a new method that utilises shadow masks in a broad ion beam system to prepare atom probe samples. It is particularly suited to non-conductors and materials with surface layers such as surface oxides, implanted layers or thin films. This new approach bypasses the focused ion beam (FIB) lift-out step, increasing the sample throughput, dramatically reducing the required FIB beam time and decreasing the complexity of sample preparation., (Copyright © 2015 Elsevier B.V. All rights reserved.)