170 research outputs found

    Challenges with Quantifying Tire Road Wear Particles: Recognizing the Need for Further Refinement of the ISO Technical Specification

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    Environmental monitoring data for tire road wear particles are vastly limited compared to those for other microplastics, primarily due to analytical challenges with quantification. Recently, two ISO technical specifications have been released using pyrolysis GC-MS for quantification. However, these methods have major assumptions, including that the content of natural and synthetic rubber in tire tread is constant across formulations and that the pyrolysis products chosen are selective. This study analyzed a wide range of commercially available tires from Australia and Norway, using pyrolysis GC-MS to test these assumptions. The percent mass of synthetic rubber in tires (n = 39) was highly variable, ranging from <0.05 to 28%, when using the ISO-recommended pyrolysis product 4-vinylcyclohexene. The content varied between brands and models, demonstrating that formulations are highly variable and unknown. The styrene butadiene dimer and trimer pyrolysis products were also assessed, and the calculated synthetic rubber content was higher, had an even greater variability, and had no correlation with concentrations calculated using 4-vinylcyclohexene. Using the ISO method has the potential to underreport environmental concentrations of TRWPs by a factor of at least 5, suggesting the specification requires further refinement, and there is an immediate need for large-scale analysis of commercial tire treads and assessments of suitable pyrolysis products.acceptedVersio

    Sugar and Polyphenolic Diversity in Floral Nectar of Cherry

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    Cherries (Prunus avium L. and Prunus cerasus L.) are economically important fruit species in the temperate region. Both are entomophilous fruit species, thus need pollinators to give high yields. Since cherry’s flower is easy-to-reach, bees and other pollinators can smoothly collect nectar as a reward for doing transfer of pollen to receptive stigma. Nectar in cherry is usually attractive for insects, especially to honey bee (Apis mellifera) who is the most common pollinator. Nectar is predominantly an aqueous solution of sugars, proteins, and free amino acids among which sugars are the most dominant. Trace amounts of lipids, organic acids, iridoid glycosides, minerals, vitamins, alkaloids, plant hormones, non-protein amino, terpenoids, glucosinolates, and cardenolides can be found in nectar too. Cherry flower may secrete nectar for 2–4 days and, depending on the cultivar, produces up to 10 mg nectar with sugar concentration from 28% to 55%. Detailed chemical analysis of cherry nectar described in this chapter is focused on sugar and phenolic profile in sour cherry. The most abounded sugars in cherry nectar was fructose, glucose, and sucrose, while arabinose, rhamnose, maltose, isomaltose, trehalose, gentiobiose, turanose, panose, melezitose, maltotriose, isomaltotriose, as well as the sugar alcohols glycerol, erythritol, arabitol, galactitol, and mannitol are present as minor constituents. Regarding polyphenolics, rutin was the most abundant phenolic compound followed by naringenin and chrysin. Cherry cultivars showed different chemical composition of nectar which implies that its content is cultivar dependent

    On the early and developed stages of surface condensation: competition mechanism between interfacial and condensate bulk thermal resistances

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    Financial supports from the National Natural Science Foundation of China (51406205), the Beijing Natural Science Foundation (3142021) and the Engineering and Physics Science Research Council (EPSRC) of the UK (EP/L001233/1) are acknowledged.Financial supports from the National Natural Science Foundation of China (51406205), the Beijing Natural Science Foundation (3142021) and the Engineering and Physics Science Research Council (EPSRC) of the UK (EP/L001233/1) are acknowledged.Financial supports from the National Natural Science Foundation of China (51406205), the Beijing Natural Science Foundation (3142021) and the Engineering and Physics Science Research Council (EPSRC) of the UK (EP/L001233/1) are acknowledged.We use molecular dynamics simulation to investigate the early and developed stages of surface condensation. We find that the liquid-vapor and solid-liquid interfacial thermal resistances depend on the properties of solid and fluid, which are time-independent, while the condensate bulk thermal resistance depends on the condensate thickness, which is time-dependent. There exists intrinsic competition between the interfacial and condensate bulk thermal resistances in timeline and the resultant total thermal resistance determines the condensation intensity for a given vapor-solid temperature difference. We reveal the competition mechanism that the interfacial thermal resistance dominates at the onset of condensation and holds afterwards while the condensate bulk thermal resistance gradually takes over with condensate thickness growing. The weaker the solid-liquid bonding, the later the takeover occurs. This competition mechanism suggests that only when the condensate bulk thermal resistance is reduced after it takes over the domination can the condensation be effectively intensified. We propose a unified theoretical model for the thermal resistance analysis by making dropwise condensation equivalent to filmwise condensation. We further find that near a critical point (contact angle being ca. 153°) the bulk thermal resistance has the least opportunity to take over the domination while away from it the probability increases.Financial supports from the National Natural Science Foundation of China (51406205), the Beijing Natural Science Foundation (3142021) and the Engineering and Physics Science Research Council (EPSRC) of the UK (EP/L001233/1) are acknowledged

    Nanofluidic transport governed by the liquid/vapour interface

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    Liquid/vapour interfaces govern the behaviour of a wide range of systems but remain poorly understood, leaving ample margin for the exploitation of intriguing functionalities for applications. Here, we systematically investigate the role of liquid/vapour interfaces in the transport of water across apposing liquid menisci in osmosis membranes comprising short hydrophobic nanopores that separate two fluid reservoirs. We show experimentally that mass transport is limited by molecular reflection from the liquid/vapour interface below a certain length scale, which depends on the transmission probability of water molecules across the nanopores and on the condensation probability of a water molecule incident on the liquid surface. This fundamental yet elusive condensation property of water is measured under near-equilibrium conditions and found to decrease from 0.36 ± 0.21 at 30 °C to 0.18 ± 0.09 at 60 °C. These findings define the regime in which liquid/vapour interfaces govern nanofluidic transport and have implications for understanding mass transport in nanofluidic devices, droplets and bubbles, biological components and porous media involving liquid/vapour interfaces.Center for Clean Water and Clean Energy at MIT and KFUPM (Project R10-CW-09

    Mindfulness in Action: Discovering How U.S. Navy Seals Build Capacity for Mindfulness in High-Reliability Organizations (HROs)

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    This study of US Navy Sea Air and Land (SEAL) commandos contributes to research investigating mindfulness in High-Reliability Organizations (HROs) by identifying the individual and collective influences that allow SEALs to build capacity for mindful behaviors despite the complexity of their missions, the unpredictability of their operating environments, and the danger inherent in their work. Although the HRO literature identifies a number of hallmarks of reliability, less attention is paid to how mindfulness is operationally achieved in situ by individuals on the frontline working in HROs. This study addresses this gap using a multi-phase, multi-method investigation of US Navy SEALs, identifying new links between individual mindfulness attributes (comfort with uncertainty and chaos) and collective mindfulness influences (a positive orientation towards failure) that combine to co-create a phenomenon we call 'mindfulness in action'. Mindfulness in action occurs when HROs achieve an attentive yet flexible focus capable of incorporating multiple—sometimes competing—realities in order to assess alternative solutions and take action in dynamic situations. By providing a more nuanced conceptualization of the links between individual mindfulness attributes and collective mindfulness influences, this paper opens up new avenues of discovery for a wide range of reliability-seeking organizations.This study of US Navy Sea Air and Land (SEAL) commandos contributes to research investigating mindfulness in High-Reliability Organizations (HROs) by identifying the individual and collective influences that allow SEALs to build capacity for mindful behaviors despite the complexity of their missions, the unpredictability of their operating environments, and the danger inherent in their work. Although the HRO literature identifies a number of hallmarks of reliability, less attention is paid to how mindfulness is operationally achieved in situ by individuals on the frontline working in HROs. This study addresses this gap using a multi-phase, multi-method investigation of US Navy SEALs, identifying new links between individual mindfulness attributes (comfort with uncertainty and chaos) and collective mindfulness influences (a positive orientation towards failure) that combine to co-create a phenomenon we call 'mindfulness in action'. Mindfulness in action occurs when HROs achieve an attentive yet flexible focus capable of incorporating multiple—sometimes competing—realities in order to assess alternative solutions and take action in dynamic situations. By providing a more nuanced conceptualization of the links between individual mindfulness attributes and collective mindfulness influences, this paper opens up new avenues of discovery for a wide range of reliability-seeking organizations

    SSR-Based Analysis of Genetic Diversity and Structure of Sweet Cherry (Prunus avium L.) from 19 Countries in Europe

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    Sweet cherry (Prunus avium L.) is a temperate fruit species whose production might be highly impacted by climate change in the near future. Diversity of plant material could be an option to mitigate these climate risks by enabling producers to have new cultivars well adapted to new environmental conditions. In this study, subsets of sweet cherry collections of 19 European countries were genotyped using 14 SSR. The objectives of this study were (i) to assess genetic diversity parameters, (ii) to estimate the levels of population structure, and (iii) to identify germplasm redundancies. A total of 314 accessions, including landraces, early selections, and modern cultivars, were monitored, and 220 unique SSR genotypes were identified. All 14 loci were confirmed to be polymorphic, and a total of 137 alleles were detected with a mean of 9.8 alleles per locus. The average number of alleles (N = 9.8), PIC value (0.658), observed heterozygosity (Ho = 0.71), and expected heterozygosity (He = 0.70) were higher in this study compared to values reported so far. Four ancestral populations were detected using STRUCTURE software and confirmed by Principal Coordinate Analysis (PCoA), and two of them (K1 and K4) could be attributed to the geographical origin of the accessions. A N-J tree grouped the 220 sweet cherry accessions within three main clusters and six subgroups. Accessions belonging to the four STRUCTURE populations roughly clustered together. Clustering confirmed known genealogical data for several accessions. The large genetic diversity of the collection was demonstrated, in particular within the landrace pool, justifying the efforts made over decades for their conservation. New sources of diversity will allow producers to face challenges, such as climate change and the need to develop more sustainable production systems

    Clinical emergence of neurometastatic merkel cell carcinoma: a surgical case series and literature review

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    Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine neoplasm of possible viral origin and is known for its aggressive behavior. The incidence of MCC has increased in the last 15 years. Merkel cell carcinoma has the potential to metastasize, but rarely involves the central nervous system. Herein, we report three consecutive surgical cases of MCC presenting at a single institution within 1 year. We used intracavitary BCNU wafers (Gliadel®) in two cases. Pathological features, including CK20 positivity, consistent with MCC, were present in all cases. We found 33 published cases of MCC with CNS involvement. We suggest that the incidence of neurometastatic MCC may be increasing, parallel to the increasing incidence of primary MCC. We propose a role for intracavitary BCNU wafers in the treatment of intra-axial neurometastatic MCC

    Biofield Therapies: Helpful or Full of Hype? A Best Evidence Synthesis

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    Biofield therapies (such as Reiki, therapeutic touch, and healing touch) are complementary medicine modalities that remain controversial and are utilized by a significant number of patients, with little information regarding their efficacy. This systematic review examines 66 clinical studies with a variety of biofield therapies in different patient populations. We conducted a quality assessment as well as a best evidence synthesis approach to examine evidence for biofield therapies in relevant outcomes for different clinical populations. Studies overall are of medium quality, and generally meet minimum standards for validity of inferences. Biofield therapies show strong evidence for reducing pain intensity in pain populations, and moderate evidence for reducing pain intensity hospitalized and cancer populations. There is moderate evidence for decreasing negative behavioral symptoms in dementia and moderate evidence for decreasing anxiety for hospitalized populations. There is equivocal evidence for biofield therapies' effects on fatigue and quality of life for cancer patients, as well as for comprehensive pain outcomes and affect in pain patients, and for decreasing anxiety in cardiovascular patients. There is a need for further high-quality studies in this area. Implications and future research directions are discussed
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