Low radiation dose in computed tomography: the role of iodine

Recent approaches to reducing radiation exposure during CT examinations typically utilize automated dose modulation strategies on the basis of lower tube voltage combined with iterative reconstruction and other dose-saving techniques. Less clearly appreciated is the potentially substantial role that iodinated contrast media (CM) can play in low-radiation-dose CT examinations. Herein we discuss the role of iodinated CM in low-radiation-dose examinations and describe approaches for the optimization of CM administration protocols to further reduce radiation dose and/or CM dose while maintaining image quality for accurate diagnosis. Similar to the higher iodine attenuation obtained at low-tube-voltage settings, high-iodine-signal protocols may permit radiation dose reduction by permitting a lowering of mAs while maintaining the signal-to-noise ratio. This is particularly feasible in first pass examinations where high iodine signal can be achieved by injecting iodine more rapidly. The combination of low kV and IR can also be used to reduce the iodine dose. Here, in optimum contrast injection protocols, the volume of CM administered rather than the iodine concentration should be reduced, since with high-iodine-concentration CM further reductions of iodine dose are achievable for modern first pass examinations. Moreover, higher concentrations of CM more readily allow reductions of both flow rate and volume, thereby improving the tolerability of contrast administration

Selecting low-flammability plants as green firebreaks within sustainable urban garden design

In response to an increasing risk of property loss from wildfires at the urban–wildland interface, there has been growing interest around the world in the plant characteristics of urban gardens that can be manipulated to minimize the chances of property damage or destruction. To date, considerable discussion of this issue can be found in the ‘grey’ literature, covering garden characteristics such as the spatial arrangement of plants in relation to each other, proximity of plants to houses, plant litter and fuel reduction, and the use of low-flammability plants as green firebreaks [1,2,3,4]. Recently, scientific studies from a geographically wide range of fire-prone regions including Europe [5], the USA [6], Australia [7], South Africa [8], and New Zealand [9] have been explicitly seeking to quantify variation among plant species with respect to different aspects of their flammability and to identify low-flammability horticultural species appropriate for implementation as green firebreaks in urban landscapes. The future prospects of this scientific work will ultimately depend on how successfully the results are integrated into the broader context of garden design in fire-prone regions at the urban–wildland interface. Although modern design of urban gardens must consider more than just the issue of green firebreaks, we and others [10,11] believe that selection of low-flammability plants should be high on the priority list of plant selection criteria in fire-prone regions

Calibrating assessment literacy through benchmarking tasks

© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. In calibration tasks students assess exemplar texts using criteria against which their own work will be assessed. Typically, these tasks are used in the context of training for peer assessment. Little research has been conducted on the benefits of calibration tasks, such as benchmarking, as learning opportunities in their own right. This paper examines a dataset from a long-running benchmarking task (∼500 students per semester, for four semesters). We investigate the relationship of benchmarking performance to other student outcomes, including ability to self-assess accurately. We show that students who complete the benchmarking perform better, that there is a relationship between benchmarking performance and self-assessment performance, and that students appreciate the support for learning that benchmarking tasks provide. We discuss implications for teaching and learning flagging the potential of calibration tasks as an under-explored tool

Overview on Multienzymatic Cascades for the Production of Non-canonical α-Amino Acids

SM-R thanks the University of Granada for the support provided by project PPJI2017-1 and the European Cooperation in Science and Technology (COST Action CA15133). Authors are also grateful to the Andalusian Regional Government through Endocrinology & Metabolism Group (CTS-202).The 22 genetically encoded amino acids (AAs) present in proteins (the 20 standard AAs together with selenocysteine and pyrrolysine), are commonly referred as proteinogenic AAs in the literature due to their appearance in ribosome-synthetized polypeptides. Beyond the borders of this key set of compounds, the rest of AAs are generally named imprecisely as non-proteinogenic AAs, even when they can also appear in polypeptide chains as a result of post-transductional machinery. Besides their importance as metabolites in life, many of D-α- and L-α-“non-canonical” amino acids (NcAAs) are of interest in the biotechnological and biomedical fields. They have found numerous applications in the discovery of new medicines and antibiotics, drug synthesis, cosmetic, and nutritional compounds, or in the improvement of protein and peptide pharmaceuticals. In addition to the numerous studies dealing with the asymmetric synthesis of NcAAs, many different enzymatic pathways have been reported in the literature allowing for the biosynthesis of NcAAs. Due to the huge heterogeneity of this group of molecules, this review is devoted to provide an overview on different established multienzymatic cascades for the production of non-canonical D-α- and L-α-AAs, supplying neophyte and experienced professionals in this field with different illustrative examples in the literature. Whereas the discovery of new or newly designed enzymes is of great interest, dusting off previous enzymatic methodologies by a “back and to the future” strategy might accelerate the implementation of new or improved multienzymatic cascades.University of Granada PPJI2017-1European Cooperation in Science and Technology (COST) CA15133Andalusian Regional Government through Endocrinology & Metabolism Group CTS-20

Contrast-enhanced ultrasound for examining tumor biology

This paper reviews the potential of ultrasound for assessing the viability and biological behavior of tumors. Unlike color Doppler sonography, modern techniques for contrast-enhanced ultrasound permit the measurement of tissue perfusion irrespective of vessel size or flow velocity. Perfusion can also be assessed quantitatively, using replenishment kinetics or derivates thereof. The perfusion of tumors is a surrogate parameter of their viability and may mirror their response to therapy. Furthermore, the degree of vascularity in a tumor may express its aggressiveness and help to predict its response to treatment. In animal models, a decrease in blood flow has been shown to precede a shrinkage of tumors treated with anti-angiogenic compounds. In liver metastases, arterial and portal blood supply can be assessed separately, and a response to stereotactic radiotherapy was found to go along with a decrease in arterial perfusion. Moreover, a relatively high arterial perfusion of liver metastases may predict a response to chemotherapy. Contrast-enhanced ultrasound may be a potent tool for assessing the effects of anti-angiogenic treatment in patients

Ecological impacts of fire trails on plant assemblages in edge habitat adjacent to trails

© 2017 Association for Fire Ecology. All rights reserved. Fire trails provide access into vegetation for controlled burns in fire-prone regions of the world. We examined the ecological impacts of fire trails on plant assemblages in edge habitat adjacent to trails in eucalypt woodlands of World Heritage Blue Mountains National Park, southeastern Australia. We found that understory plant species richness, total plant density, and leaf mass per area (LMA) were significantly higher in fire-trail edge habitat than in the understory of interior woodland habitat without fire trails. Understory plant species composition also differed significantly between fire-trail edge and interior habitats. Higher total plant density, higher LMA, and compositional differences in understory assemblages of fire-trail edge habitat were significantly related to increases in the availability of photosynthetically active radiation. In addition, higher soil clay content in fire-trail edges, which is linked to increased soil water availability for plant growth, was significantly related to higher species richness and compositional differences in the understory, as well as to compositional differences in overstory assemblages. From a conservation and management perspective, we suggest that, although significant ecological effects of fire trails on plant assemblages in edge habitats were detected, our work provides evidence that fire trails are unlikely to lead to serious conservation issues such as local extirpations of native species or the facilitation of exotic plant invasion. Nevertheless, our study has identified those plant species that are unique to, or particularly sparse or common in, fire-trail habitat, which should be prioritized for demographic and distributional monitoring should the need arise to increase the extent of fire trails in the future

Contrast-Enhanced Ultrasound for Musculoskeletal Applications: A World Federation for Ultrasound in Medicine and Biology Position Paper

This World Federation for Ultrasound in Medicine and Biology position paper reviews the diagnostic potential of ultrasound contrast agents for clinical decision-making and provides general advice for optimal contrast-enhanced ultrasound performance in musculoskeletal issues. In this domain, contrast-enhanced ultrasound performance has increasingly been investigated with promising results, but still lacks everyday clinical application and standardized techniques; therefore, experts summarized current knowledge according to published evidence and best personal experience. The goal was to intensify and standardize the use and administration of ultrasound contrast agents to facilitate correct diagnoses and ultimately to improve the management and outcomes of patients. (E-mail addresses: [email protected], [email protected]) (C) 2020 World Federation for Ultrasound in Medicine & Biology. All rights reserved

An Integrated Approach to Identify Low-Flammability Plant Species for Green Firebreaks

With recent and predicted increases in the frequency and intensity of wildfires, there is a pressing need for mitigation strategies to reduce the impacts of wildfires on human lives, infrastructure and biodiversity. One strategy involves the use of low-flammability plants to build green firebreaks at the wildland–urban interface. It is common, however, to encounter uncertainty in a diverse range of stakeholders about the concept of flammability as it applies to plants, which may impede efforts to identify suitable low-flammability plant species. Here, we provide an approach to identify low-flammability plant species that integrates three fundamental and relatively easy-to-measure plant-flammability attributes – ignitibility, sustainability and combustibility – in a way that removes confusion about the concept of plant flammability. These three intrinsic flammability attributes relate to each other such that an ideal low-flammability species is one that is slow to ignite, sustains burning for a short period of time and combusts with low intensity. Consideration is then given to secondary attributes of plants critical to the selection of low-flammability plants, including attributes that influence the volume of fuel available for fires and the vertical and horizontal spread of fires. More work is urgently needed across the world to identify low-flammability plant species using standardised measurement protocols, and our integrated approach provides a transparent way to ensure we are selecting the right species, for the right location, in green firebreaks