10,958 research outputs found

    Challenges in imaging and predictive modeling of rhizosphere processes

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    Background Plant-soil interaction is central to human food production and ecosystem function. Thus, it is essential to not only understand, but also to develop predictive mathematical models which can be used to assess how climate and soil management practices will affect these interactions. Scope In this paper we review the current developments in structural and chemical imaging of rhizosphere processes within the context of multiscale mathematical image based modeling. We outline areas that need more research and areas which would benefit from more detailed understanding. Conclusions We conclude that the combination of structural and chemical imaging with modeling is an incredibly powerful tool which is fundamental for understanding how plant roots interact with soil. We emphasize the need for more researchers to be attracted to this area that is so fertile for future discoveries. Finally, model building must go hand in hand with experiments. In particular, there is a real need to integrate rhizosphere structural and chemical imaging with modeling for better understanding of the rhizosphere processes leading to models which explicitly account for pore scale processes

    Small-scale patterning methods for digital image correlation under scanning electron microscopy

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    Digital image correlation (DIC) is a powerful, length-scale-independent methodology for examining full-field surface deformations. Recently, it has become possible to combine DIC with scanning electron microscopy (SEM), enabling the investigation of small-scale deformation mechanisms such as the strains accommodated within grains in polycrystalline metals, or around micro-scale constituents in composite materials. However, there exist significant challenges that need to be surmounted before the combination of DIC and SEM (here termed SEM-DIC) can be fully exploited. One of the primary challenges is the ability to pattern specimens at microstructural length scales with a random, isotropic and high contrast pattern needed for DIC. This paper provides a thorough survey of small-scale patterning methods for SEM-DIC and discusses their advantages and disadvantages for different applications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90784/1/0957-0233_22_12_125501.pd

    Neural and physiological data from participants listening to affective music

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    Music provides a means of communicating affective meaning. However, the neurological mechanisms by which music induces affect are not fully understood. Our project sought to investigate this through a series of experiments into how humans react to affective musical stimuli and how physiological and neurological signals recorded from those participants change in accordance with self-reported changes in affect. In this paper, the datasets recorded over the course of this project are presented, including details of the musical stimuli, participant reports of their felt changes in affective states as they listened to the music, and concomitant recordings of physiological and neurological activity. We also include non-identifying meta data on our participant populations for purposes of further exploratory analysis. This data provides a large and valuable novel resource for researchers investigating emotion, music, and how they affect our neural and physiological activity

    Phosphorus sorption, supply potential and availability in soils with contrasting parent material and soil chemical properties

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    Soil phosphorus (P) management requires a more targeted and soil-specific approach than is currently applied for agronomic recommendations and environmental evaluation. Phosphorus buffering capacities control the supply of P in the soil solution and were measured across Irish soils with contrasting parent material and chemical properties. Langmuir sorption buffer capacities (MBCs) and binding energies (b) were strongly correlated with soil pH and extractable aluminium (Al). A broken-line regression fitted to the relationship between MBC and Al derived a change-point value for Al above which MBC increased linearly. Soils above the change point were predominantly acidic to neutral with non-calcareous parent material, with larger buffering capacities and binding energies than calcareous soils. Ratios of Mehlich3-Al and P (Al:P) were used to relate buffering capacity to supply potential in non-calcareous soils. Large ratios of Al:P were associated with poor P availability, characteristic of strongly P-fixing soils. Threshold values of iron-oxide paper strip P (FeO-P) and Morgan's P revealed Al:P ratios where soils began to supply P in available form. The change-point for Morgan's P fell within the current target index for P availability; however, the confidence interval was more compatible with previous agronomic P indices used in Ireland. Relationships between Morgan's P and measures of extractable P, M3-P and Olsen P, deviated in calcareous soils at large soil P contents, indicative of P precipitation processes dominating in these soils. Identifying differences in soil P buffering capacity at the laboratory scale would improve agronomic and environmental assessment at field and catchment scales

    Listeriolysin S, a Novel Peptide Haemolysin Associated with a Subset of Lineage I Listeria monocytogenes

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    peer-reviewedStreptolysin S (SLS) is a bacteriocin-like haemolytic and cytotoxic virulence factor that plays a key role in the virulence of Group A Streptococcus (GAS), the causative agent of pharyngitis, impetigo, necrotizing fasciitis and streptococcal toxic shock syndrome. Although it has long been thought that SLS and related peptides are produced by GAS and related streptococci only, there is evidence to suggest that a number of the most notorious Gram-positive pathogenic bacteria, including Listeria monocytogenes, Clostridium botulinum and Staphylococcus aureus, produce related peptides. The distribution of the L. monocytogenes cluster is particularly noteworthy in that it is found exclusively among a subset of lineage I strains; i.e., those responsible for the majority of outbreaks of listeriosis. Expression of these genes results in the production of a haemolytic and cytotoxic factor, designated Listeriolysin S, which contributes to virulence of the pathogen as assessed by murine- and human polymorphonuclear neutrophil–based studies. Thus, in the process of establishing the existence of an extended family of SLS-like modified virulence peptides (MVPs), the genetic basis for the enhanced virulence of a proportion of lineage I L. monocytogenes may have been revealed.Work is funded by the Irish Government under the National Development Plan, through a Science Foundation Ireland Investigator award to CH, PR and PC (06/IN.1/B98)

    Inkjet printing for pharmaceutics - A review of research and manufacturing.

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    Global regulatory, manufacturing and consumer trends are driving a need for change in current pharmaceutical sector business models, with a specific focus on the inherently expensive research costs, high-risk capital-intensive scale-up and the traditional centralised batch manufacturing paradigm. New technologies, such as inkjet printing, are being explored to radically transform pharmaceutical production processing and the end-to-end supply chain. This review provides a brief summary of inkjet printing technologies and their current applications in manufacturing before examining the business context driving the exploration of inkjet printing in the pharmaceutical sector. We then examine the trends reported in the literature for pharmaceutical printing, followed by the scientific considerations and challenges facing the adoption of this technology. We demonstrate that research activities are highly diverse, targeting a broad range of pharmaceutical types and printing systems. To mitigate this complexity we show that by categorising findings in terms of targeted business models and Active Pharmaceutical Ingredient (API) chemistry we have a more coherent approach to comparing research findings and can drive efficient translation of a chosen drug to inkjet manufacturing.This project was supported by (i) the UK Engineering and Physical Sciences Research Council and industrial partners in the Programme Grant number EP/H018913/1 ‘Innovation in Industrial Inkjet Technology’, (ii) EPSRC Centre for Innovative Manufacturing in Continuous Manufacturing and Crystallisation (EP/1033459/1) and (iii) Department of Business, Innovation and Skill’s (BIS) Advanced Manufacturing Supply Chain Initiative (AMSCI) funded Project ‘Remedies’ (TS/L006529/1).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ijpharm.2015.03.01

    The Highly Miniaturised Radiation Monitor

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    We present the design and preliminary calibration results of a novel highly miniaturised particle radiation monitor (HMRM) for spacecraft use. The HMRM device comprises a telescopic configuration of active pixel sensors enclosed in a titanium shield, with an estimated total mass of 52 g and volume of 15 cm3^3. The monitor is intended to provide real-time dosimetry and identification of energetic charged particles in fluxes of up to 108^8 cm−2^{-2} s−1^{-1} (omnidirectional). Achieving this capability with such a small instrument could open new prospects for radiation detection in space.Comment: 17 pages, 15 figure

    Crater Morphometry and Scaling in Coarse, Rubble-Like Targets: Insights from Impact Experiments

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    Spacecraft images reveal that the asteroids Itokawa, Ryugu, and Bennu are covered with coarse, boulder-rich material [13]. Impactors that collide with these bodies encounter a target with extreme physical heterogeneity. Other bodies can also possess significant physical heterogeneity (e.g., megaregolith, layering, etc.). Such heterogeneities establish free surfaces and impedance contrasts that can affect shock propagation and attenuation. Therefore, such heterogeneities may also affect crater formation and excavation [4], melt generation [57] and crater scaling [4]. As described by [8,9], the extent to which target heterogeneity affects crater formation likely depends on how the length scale, d, of the heterogeneity (e.g., boulder size on a rubble-pile asteroid) compares to the width of the shock, w, generated by impact. Here we further test this hypothesis using impact experiments across a broad range of impact velocities and target grain sizes to systematically vary the ratio between the width of the shock and the diameter of target grains

    Thermocurrents and their Role in high Q Cavity Performance

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    Over the past years it became evident that the quality factor of a superconducting cavity is not only determined by its surface preparation procedure, but is also influenced by the way the cavity is cooled down. Moreover, different data sets exists, some of them indicate that a slow cool-down through the critical temperature is favourable while other data states the exact opposite. Even so there where speculations and some models about the role of thermo-currents and flux-pinning, the difference in behaviour remained a mystery. In this paper we will for the first time present a consistent theoretical model which we confirmed by data that describes the role of thermo-currents, driven by temperature gradients and material transitions. We will clearly show how they impact the quality factor of a cavity, discuss our findings, relate it to findings at other labs and develop mitigation strategies which especially addresses the issue of achieving high quality factors of so-called nitrogen doped cavities in horizontal test
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