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In this work, germanium nanowires rendered fully amorphous via xenon ion irradiation have been annealed within a transmission electron microscope to induce crystallization. During annealing crystallites appeared in some nanowires whilst others remained fully amorphous. Remarkably, even when nucleation occurred, large sections of the nanowires remained amorphous even though the few crystallites embedded in the amorphous phase were formed at a minimum of 200 °C above the temperature for epitaxial growth and 100 °C above the temperature for random nucleation and growth in bulk germanium. Furthermore, the presence of crystallites was observed to depend on the diameter of the nanowire. Indeed, the formation of crystallites occurred at a higher annealing temperature in thin nanowires compared with thicker ones. Additionally, nanowires with a diameter above 55 nm were made entirely crystalline when the annealing was performed at the temperature normally required for crystallization in germanium (i.e. 500 °C). It is proposed that oxygen atoms hinder both the formation and the growth of crystallites. Furthermore, as crystallites must reach a minimum size to survive and grow within the amorphous nanowires, the instability of crystallites may also play a limited role for the thinnest nanowires. [ABSTRACT FROM AUTHOR]

In this work, ion implantations with in situ transmission electron microscopy observations followed by different rates of temperature ramp were performed in (001)-Si to follow the evolution of Heplates under the influence of hydrogen. The JANNUS and MIAMI facilities were used to study the first stages of growth as well as the interactions between co-planar plates. Results showed that under a limited amount of H, the growth of He-plates resulting from a subcritical stress-corrosion mechanism can be fully described by the kinetic model of Johnson-Mehl-Avrami-Kolmogorov with effective activation energy of 0.9 eV. Elastic calculations showed that the sudden and nonisotropic coalescence of close He-plates occurs when the out-of-plane tensile stress between them is close to the yield strength of silicon. After hydrogen absorption, surface minimization of final structure occurs. [ABSTRACT FROM AUTHOR]

Transmission electron microscopy (TEM) has been used to investigate the effects of room temperature 6 keV helium ion irradiation of a thin (≈55 nm thick) tri-layer consisting of polycrystalline Si, silica, and single-crystal Si. The ion irradiation was carried out in situ within the TEM under conditions where approximately 24% of the incident ions came to rest in the specimen. This paper reports on the comparative development of irradiation-induced defects (primarily helium bubbles) in the polycrystalline Si and single-crystal Si under ion irradiation and provides direct measurement of a radiation-induced increase in the width of the polycrystalline layer and shrinkage of the silica layer. Analysis using TEM and electron energy-loss spectroscopy has led to the hypothesis that these result from helium-bubble-induced swelling of the silicon and radiation-induced viscoelastic flow processes in the silica under the influence of stresses applied by the swollen Si layers. The silicon and silica layers are sputtered as a result of the helium ion irradiation; however, this is estimated to be a relatively minor effect with swelling and stress-related viscoelastic flow being the dominant mechanisms of dimensional change. [ABSTRACT FROM AUTHOR]

Copper indium diselenide (CIS), along with its derivatives Cu(In,Ga)(Se,S)2, is a prime candidate for use in the absorber layers of photovoltaic devices. Due to its ability to resist radiation damage, it is particularly well suited for use in extraterrestrial and other irradiating environments. However, the nature of its radiation hardness is not well understood. In this study, transmission electron microscopy (TEM) with in situ ion irradiation was used to monitor the dynamic microstructural effects of radiation damage on CIS. Samples were bombarded with 400 keV xenon ions to create large numbers of atomic displacements within the thickness of the TEM samples and thus explore the conditions under which, if any, CIS could be amorphized. By observing the impact of heavily damaging radiation in situ-rather than merely the end-state possible in ex situ experiments-at the magnifications allowed by TEM, it was possible to gain an understanding of the atomistic processes at work and the underlying mechanism that give rise to the radiation hardness of CIS. At 200 K and below, it was found that copper-poor samples could be amorphized and copper-rich samples could not. This difference in behavior is linked to the crystallographic phases that are present at different compositions. Amorphization was found to progress via a combination of one- and two-hit processes. The radiation hardness of CIS is discussed in terms of crystallographic structures/defects and the consequences these have for the ability of the material to recover from the effects of displacing radiation. [ABSTRACT FROM AUTHOR]

Nanocrystalline metals are considered highly radiation-resistant materials due to their large grain boundary areas. Here, the existence of a grain size threshold for enhanced irradiation resistance in high-temperature helium-irradiated nanocrystalline and ultrafine tungsten is demonstrated. Average bubble density, projected bubble area and the corresponding change in volume were measured via transmission electron microscopy and plotted as a function of grain size for two ion fluences. Nanocrystalline grains of less than 35 nm size possess ∼10–20 times lower change in volume than ultrafine grains and this is discussed in terms of the grain boundaries defect sink efficiency. IMPACT STATEMENT A grain size threshold in nanocrystalline and ultrafine tungsten has been shown to exist for enhanced irradiation-resistance performance during high-temperature helium irradiation. [ABSTRACT FROM PUBLISHER]

In Pseudomonas aeruginosa, chemical deconvolution of the pyocyanin voltammetric signal allows its expression to be observed simultaneously with the quorum sensing molecule Pseudomonas quinolone signal (PQS). Such analysis has revealed that PQS might protect pyocyanin from self-oxidation, but also exert a pro-oxidative effect on pyocyanin under oxidative conditions to produce additional redox metabolites. [ABSTRACT FROM AUTHOR]

Sputtering yields, enhanced by more than an order of magnitude, have been observed for 80 keV Xe ion irradiation of monocrystalline Au nanorods. Yields are in the range 100-1900 atoms/ion compared with values for a flat surface of ≈50. This enhancement results in part from the proximity of collision cascades and ensuing thermal spikes to the nanorod surfaces. Molecular dynamic modeling reveals that the range of incident angles occurring for irradiation of nanorods and the larger number of atoms in "explosively ejected" atomic clusters make a significant contribution to the enhanced yield. [ABSTRACT FROM AUTHOR]

A transmission electron microscope (TEM) with in situ ion irradiation has been built at the University of Salford, U.K. The system consists of a Colutron G-2 ion source connected to a JEOL JEM-2000FX TEM via an in-house designed and constructed ion beam transport system. The ion source can deliver ion energies from 0.5 to 10 keV for singly charged ions and can be floated up to 100 kV to allow acceleration to higher energies. Ion species from H to Xe can be produced for the full range of energies allowing the investigation of implantation with light ions such as helium as well as the effects of displacing irradiation with heavy inert or self-ions. The ability to implant light ions at energies low enough such that they come to rest within the thickness of a TEM sample and to also irradiate with heavier species at energies sufficient to cause large numbers of atomic displacements makes this facility ideally suited to the study of materials for use in nuclear environments. TEM allows the internal microstructure of a sample to be imaged at the nanoscale. By irradiating in situ it is possible to observe the dynamic evolution of radiation damage which can occur during irradiation as a result of competing processes within the system being studied. Furthermore, experimental variables such as temperature can be controlled and maintained throughout both irradiation and observation. This combination of capabilities enables an understanding of the underlying atomistic processes to be gained and thus gives invaluable insights into the fundamental physics governing the response of materials to irradiation. Details of the design and specifications of the MIAMI facility are given along with examples of initial experimental results in silicon and silicon carbide. [ABSTRACT FROM AUTHOR]

Copper indium diselenide (CIS) is a prime candidate as the absorber layer in solar cells for use in extraterrestrial environments due to its good photovoltaic efficiency and ability to resist radiation damage. While CIS-based devices have been tested extensively in the laboratory using electron and proton irradiation, there is still little understanding of the underlying mechanisms which give rise to its radiation hardness. To gain better insight into the response of CIS to displacing radiation, transmission electron microscope samples have been irradiated in situ with 400 keV Xe ions at the Intermediate Voltage Electron Microscope facility at Argonne National Laboratory, USA. At room temperature, dislocation loops were observed to form and grow with increasing fluence. These loops have been investigated using g · b techniques and inside/outside contrast analysis. They have been found to reside on {112} planes and to be interstitial in nature. The Burgers vector were calculated as b = 1/6 〈221〉. The compositional content of these interstitial loops was found to be indistinguishable from the surrounding matrix within the sensitivity of the techniques used. To facilitate this work, experimental electron-diffraction zone-axis pattern maps were produced and these are also presented, along with analysis of the [100] zone-axis pattern. [ABSTRACT FROM AUTHOR]

This study examined how groups representing four tiers in the chemical supply chain (manufacturers, vendors, workers and consumers) understood safety information, and the factors that influenced disposal behaviour. Data from seven, semi-structured, focus groups was analysed both qualitatively (textual analysis) and quantitatively (network analysis). Such combined analytical methods enabled us to achieve both detailed insights into perceptions and behaviour and an objective understanding of the prevailing opinions that occurred within and between the focus group discussions. We found issues around awareness, trust, access and disposal behaviours differed between groups within the supply chain. Participants from the lower tiers perceived chemical safety information to be largely inaccessible. Labels were the main source of information on chemical risks for the middle and bottom tiers of the supply chain. Almost all of the participants were aware of the St Andrew''s Cross and skull and crossbones symbols but few were familiar with the Volatile Organic Compound logo or the fish and tree symbol. Both the network and thematic analysis demonstrated that whilst frequent references to health risks associated with chemicals were made environmental risks were usually only articulated after prompting. It is clear that the issues surrounding public understanding of chemical safety labels are highly complex and this is compounded by inconsistencies in the cognitive profiles of chemical users. Substantially different cognitive profiles are likely to contribute towards communication difficulties between different tiers of the supply chain. Further research is needed to examine the most effective ways of communicating chemical hazards information to the public. The findings demonstrate a need to improve and simplify disposal guidance to members of the public, to raise public awareness of the graphic symbols in the CHIP 3.1, 2005 regulations and to improve access to disposal guidance. [Copyright &y& Elsevier]

The paper discusses the potential impact of videoconferencing on practices and processes within the construction industry, based on analyses carried out on its use and impact in the healthcare sector – which like construction involves technology-intensive processes which are dependent upon cross-professional and cross-disciplinary relationships and communications, operate within an increasingly regulatory and litigious climate, and involve organizationally fluid, virtual, teams spanning several subindustries. Recently published research evidence from the healthcare sector suggests that whilst videoconferencing and other advanced information and communication technologies (ICTs) have pervasive capabilities, successes in their application may be shortlived and modest in achievement. In use, their actual uptake and application have been found to be fundamentally affected by a range of social and operational issues, such as fears over a new formalization and trackability of previously informal conversations; a rebalancing of power relationships (between professionals using the ICTs as well as between doctor and patient); pressures on social/cultural and procedural alignment between participants; and personal and corporate attitudes to the technologies (including simply disliking the ICT). There is also evidence from the healthcare sector to suggest that ICTs increase the complexity of the delivering healthcare, and that the limitations of the technologies emphasise an existing dependency of communications and processes on tacit knowledge which is not readily formalized for communication via ICTs. However, the paper also notes an increasing pressure on the construction industry to respond to the globalizing potential that ICTs offer for the supply and delivery of knowledge-based services, and discusses the implications of the issues found in the healthcare sector for the use and potential abuse of ICTs in the construction industry that will have to be successfully addressed in order to avoid ICTs being perceived as threatening and to allow their use to help organizations address the globalising marketplace. [ABSTRACT FROM AUTHOR]

The effect of helium implantation fluences on He bubble nucleation and growth mechanisms in nuclear borosilicate glass has been characterized using in-situ transmission electron microscopy experiments. Observations of implanted glass at 143 K indicate that a helium concentration of around 3 at.% is required to nucleate a significant density of nanosized bubbles. He bubble growth is observed for concentration higher than the number of host sites (>4 at.%). These results highlight the large capacity of the glassy network for incorporating helium atoms. [ABSTRACT FROM AUTHOR]

Priority question exercises are increasingly used to frame and set future research, innovation and development agendas. They can provide an important bridge between the discoveries, data and outputs generated by researchers, and the information required by policy makers and funders. Microbial biofilms present huge scientific, societal and economic opportunities and challenges. In order to identify key priorities that will help to advance the field, here we review questions from a pool submitted by the international biofilm research community and from practitioners working across industry, the environment and medicine. To avoid bias we used computational approaches to group questions and manage a voting and selection process. The outcome of the exercise is a set of 78 unique questions, categorized in six themes: (i) Biofilm control, disruption, prevention, management, treatment (13 questions); (ii) Resistance, persistence, tolerance, role of aggregation, immune interaction, relevance to infection (10 questions); (iii) Model systems, standards, regulatory, policy education, interdisciplinary approaches (15 questions); (iv) Polymicrobial, interactions, ecology, microbiome, phage (13 questions); (v) Clinical focus, chronic infection, detection, diagnostics (13 questions); and (vi) Matrix, lipids, capsule, metabolism, development, physiology, ecology, evolution environment, microbiome, community engineering (14 questions). The questions presented are intended to highlight opportunities, stimulate discussion and provide focus for researchers, funders and policy makers, informing future research, innovation and development strategy for biofilms and microbial communities., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Given his role as Co-Editor in Chief, TOM COENYE had no involvement in the peer review of this article and has no access to information regarding its peer review. Full responsibility for the editorial process for this article was delegated to BIRTHE KJELLERUP. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

We report the complete genome sequence of Methylomonas sp. UP202 isolated from an urban waterway sediment in Singapore. The genome contains genes involved in methane, methanol, formaldehyde, and formate oxidation. It also contains genes utilizing various nitrogen sources such as nitrogen, nitrate, nitrite, urea, and ammonium., Competing Interests: The authors declare no conflict of interest.

Background: Alcohol is a good and environment-friendly fuel that can be microbially produced, capable of eliminating many of the limitations of the present-day fossil fuels. However, the inherent toxic nature of alcohols to the microbial cells leads to end-product inhibition that limits large-scale alcohol production by fermentation. Fundamental knowledge about the stress responses of microorganisms to alcohols would greatly facilitate to improve the microbial alcohol tolerance. The current study elucidates and compares the changes in the membrane proteome of Escherichia coli in response to a range of alcohols., Results: Although alcohol toxicity increased exponentially with alcohol chain length (2-6 carbon), similar stress responses were observed in the inner and outer membrane proteome of E. coli in the presence of 2-, 4- and 6-carbon alcohols at the MIC 50 . This pertains to: (1) increased levels of inner membrane transporters for uptake of energy-producing metabolites, (2) reduced levels of non-essential proteins, associated with anaerobic, carbon starvation and osmotic stress, for energy conservation, (3) increased levels of murein degrading enzymes (MltA, EmtA, MliC and DigH) promoting cell elongation and 4) reduced levels of most outer membrane β-barrel proteins (LptD, FadL, LamB, TolC and BamA). Major outer membrane β-barrel protein OmpC, which is known to contribute to ethanol tolerance and membrane integrity, was notably reduced by alcohol stress. While LPS is important for OmpC trimerisation, LPS release by EDTA did not lower OmpC levels. This suggests that LPS release, which is reported under alcohol stress, does not contribute to the reduced levels of OmpC in the presence of alcohol., Conclusions: Since alcohol primarily targets the integrity of the membrane, maintenance of outer membrane OmpC levels in the presence of alcohol might help in the survival of E. coli to higher alcohol concentrations. The study provides important information about the membrane protein responses of E. coli to a range of alcohols, which can be used to develop targeted strategies for increased microbial alcohol tolerance and hence bioalcohol production., (© 2023. BioMed Central Ltd., part of Springer Nature.)