963 research outputs found

    Feed-back on the development of a small scale Contact Erosion Test in the laboratory (characteristic size ~ 30 cm)

    Get PDF
    To determine the hydraulic load requested to initiate contact erosion process, tests are performed with an apparatus called the “Contact Erosion Test”. This device originally results from research carried out by Grenoble University, Électricité de France and Compagnie Nationale du Rhône, at the scale of ~60 cm. It has been adapted to a smaller scale in geophyConsult laboratory to conduct tests on samples extracted from core drilling. The instrumentation was improved to enable a better control of the hydraulic loading and avoid biases. The test protocol was modified, especially to better constrain the soil density at the interface. From the first series of test, we drew conclusions on the test repeatability and on the influence of parameters of the soil state. Discrepancies with previous results obtained at the scale of ~60 cm were identified. Therefore, a new erosion test campaign was planned to confirm and determine the reasons for these differences

    Effect of surficial geology mapping scale on modelled ground ice in Canadian Shield terrain

    Get PDF
    Ground ice maps at small scales offer generalized depictions of abundance across broad circumpolar regions. In this paper, the effect of surficial geology mapping scale on modelled ground ice abundance is examined in the Slave Geological Province of the Canadian Shield, a region where the geological and glacial legacy has produced a landscape with significant variation in surface cover. Existing model routines from the Ground ice map of Canada (GIMC) were used with a 1:125 000-scale regional surficial geology compilation and compared to the national outputs, which are based on surficial geology at a 1:5 000 000 scale. Overall, the regional-scale modelling predicts much more ground ice than the GIMC due to greater representation of unconsolidated sediments in the region. Improved modelling accuracy is indicated by comparison of the outputs to empirical datasets due to improved representation of the inherent regional heterogeneity in surficial geology. The results demonstrate that the GIMC significantly underestimates the abundance and distribution of ground ice over Canadian Shield terrain. In areas with limited information on ground ice, regional-scale modelling may provide useful reconnaissance-level information to help guide the field-based investigations required for planning infrastructure development. The use of current small-scale ground ice mapping in risk or cost assessments related to permafrost thaw may significantly influence the accuracy of outputs in areas like the Canadian Shield, where surficial materials range from bedrock to frost-susceptible deposits over relatively short distances.</p

    Has education lost sight of children?

    Get PDF
    The reflections presented in this chapter are informed by clinical and personal experiences of school education in the UK. There are many challenges for children and young people in the modern education system and for the professionals who support them. In the UK, there are significant gaps between the highly selective education provided to those who pay privately for it and to the majority of those educated in the state-funded system. Though literacy rates have improved around the world, many children, particularly boys, do not finish their education for reasons such as boredom, behavioural difficulties or because education does not ‘pay’. Violence, bullying, and sexual harassment are issues faced by many children in schools and there are disturbing trends of excluding children who present with behavioural problems at school whose origins are not explored. Excluded children are then educated with other children who may also have multiple problems which often just make the situation worse. The experience of clinicians suggests that school-related mental health problems are increasing in severity. Are mental health services dealing with the consequences of an education system that is not meeting children’s needs? An education system that is testing- and performance-based may not be serving many children well if it is driving important decisions about them at increasingly younger ages. Labelling of children and setting them on educational career paths can occur well before they reach secondary schools, limiting potential very early on in their developmental trajectory. Furthermore, the emphasis at school on testing may come at the expense of creativity and other forms of intelligence, which are also valuable and important. Meanwhile the employment marketplace requires people with widely different skills, with an emphasis on innovation, creativity, and problem solving. Is education losing sight of the children it is educating

    Congenital syndactyly in cattle: four novel mutations in the low density lipoprotein receptor-related protein 4 gene (LRP4)

    Get PDF
    BACKGROUND: Isolated syndactyly in cattle, also known as mulefoot, is inherited as an autosomal recessive trait with variable penetrance in different cattle breeds. Recently, two independent mutations in the bovine LRP4 gene have been reported as the primary cause of syndactyly in the Holstein and Angus cattle breeds. RESULTS: We confirmed the previously described LRP4 exon 33 two nucleotide substitution in most of the affected Holstein calves and revealed additional evidence for allelic heterogeneity by the identification of four new LRP4 non-synonymous point mutations co-segregating in Holstein, German Simmental and Simmental-Charolais families. CONCLUSION: We confirmed a significant role of LRP4 mutations in the pathogenesis of congenital syndactyly in cattle. The newly detected missense mutations in the LRP4 gene represent independent mutations affecting different conserved protein domains. However, the four newly described LRP4 mutations do still not explain all analyzed cases of syndactyly

    Impact of Splenic Artery Embolization on the Success Rate of Nonoperative Management for Blunt Splenic Injury

    Get PDF
    Introduction Nonoperative management (NOM) has become the treatment of choice for hemodynamically stable patients with blunt splenic injury. Results of outcome after NOM are predominantly based on large-volume studies from level 1 trauma centers in the United States. This study was designed to assess the results of NOM in a relatively low-volume Dutch level 1 trauma center. Methods An analysis of a prospective trauma registry was performed for a 6-year period before (period 1) and after the introduction and implementation of splenic artery embolization (SAE) (period 2). Primary outcome was the failure rate of initial treatment. Results A total of 151 patients were reviewed. An increased use of SAE and a reduction of splenic operations during the second period was observed. Compared with period 1, the failure rate after observation in period 2 decreased from 25% to 10%. The failure rate after SAE in period 2 was 18%. The splenic salvage rate (SSR) after observation increased from 79% in the first period to 100% in the second period. During the second period, all patients with failure after observation were successfully treated with SAE. The SSR after SAE in periods 1 and 2 was respectively 100% and 86%. Conclusions SAE of patients with blunt splenic injuries is associated with a reduction in splenic operations. The failure and splenic salvage rates in this current study were comparable with the results from large-volume studies of level 1 trauma centers. Nonoperative management also is feasible in a relatively low-volume level 1 trauma center outside the United State

    Extracellular DNA release, quorum sensing, and PrrF1/F2 small RNAs are key players in Pseudomonas aeruginosa tobramycin-enhanced biofilm formation

    Get PDF
    Biofilms are structured microbial communities that are the leading cause of numerous chronic infections which are difficult to eradicate. Within the lungs of individuals with cystic fibrosis (CF), Pseudomonas aeruginosa causes persistent biofilm infection that is commonly treated with aminoglycoside antibiotics such as tobramycin. However, sublethal concentrations of this aminoglycoside were previously shown to increase biofilm formation by P. aeruginosa, but the underlying adaptive mechanisms still remain elusive. Herein, we combined confocal laser scanning microscope analyses, proteomics profiling, gene expression assays and phenotypic studies to unravel P. aeruginosa potential adaptive mechanisms in response to tobramycin exposure during biofilm growth. Under this condition, we show that the modified biofilm architecture is related at least in part to increased extracellular DNA (eDNA) release, most likely as a result of biofilm cell death. Furthermore, the activity of quorum sensing (QS) systems was increased, leading to higher production of QS signaling molecules. We also demonstrate upon tobramycin exposure an increase in expression of the PrrF small regulatory RNAs, as well as expression of iron uptake systems. Remarkably, biofilm biovolumes and eDNA relative abundances in pqs and prrF mutant strains decrease in the presence of tobramycin. Overall, our findings offer experimental evidences for a potential adaptive mechanism linking PrrF sRNAs, QS signaling, biofilm cell death, eDNA release, and tobramycin-enhanced biofilm formation in P. aeruginosa. These specific adaptive mechanisms should be considered to improve treatment strategies against P. aeruginosa biofilm establishment in CF patients’ lungs

    Early changes within the lymphocyte population are associated with the development of multiple organ dysfunction syndrome in trauma patients

    Get PDF
    2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.JM was funded, in part, by the Royal College of Surgeons of England, The Phillip King Charitable Trust Research Fellowship and The National Institute of Health Research (NIHR)

    Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D

    Get PDF
    [EN] Single metal atoms and metal clusters have attracted much attention thanks to their advantageous capabilities as heterogeneous catalysts. However, the generation of stable single atoms and clusters on a solid support is still challenging. Herein, we report a new strategy for the generation of single Pt atoms and Pt clusters with exceptionally high thermal stability, formed within purely siliceous MCM-22 during the growth of a two-dimensional zeolite into three dimensions. These subnanometric Pt species are stabilized by MCM-22, even after treatment in air up to 540 degrees C. Furthermore, these stable Pt species confined within internal framework cavities show size-selective catalysis for the hydrogenation of alkenes. High-temperature oxidation-reduction treatments result in the growth of encapsulated Pt species to small nanoparticles in the approximate size range of 1 to 2 nm. The stability and catalytic activity of encapsulated Pt species is also reflected in the dehydrogenation of propane to propylene.This work was funded by the Spanish Government (Consolider Ingenio 2010-MULTICAT (CSD2009-00050) and MAT2014-52085-C2-1-P) and by the Generalitat Valenciana (Prometeo). The Severo Ochoa Program (SEV-2012-0267) is gratefully acknowledged. L.L. thanks ITQ for a contract. The authors also thank the Microscopy Service of UPV for the TEM and STEM measurements. The HAADF-HRSTEM works were conducted in the Laboratorio de Microscopias Avanzadas (LMA) at the Instituto de Nanociencia de Aragon (INA)-Universidad de Zaragoza (Spain), a Spanish ICTS National Facility. Some of the research leading to these results has received funding from the European Union Seventh Framework Program under Grant Agreement 312483-ESTEEM2 (Integrated Infrastructure Initiative-I3). R.A. also acknowledges funding from the Spanish Ministerio de Economia y Competitividad (FIS2013-46159-C3-3-P) and the European Union Horizon 2020 research and innovation programme under the Marie Sldodowska-Curie grant agreement No. 642742.Liu, L.; Díaz Morales, UM.; Arenal, R.; Agostini, G.; Concepción Heydorn, P.; Corma Canós, A. (2017). Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D. Nature Materials. 16(1):132-138. https://doi.org/10.1038/NMAT4757S132138161Boronat, M., Leyva-Perez, A. & Corma, A. Theoretical and experimental insights into the origin of the catalytic activity of subnanometric gold clusters: attempts to predict reactivity with clusters and nanoparticles of gold. Acc. Chem. Res. 47, 834–844 (2014).Flytzani-Stephanopoulos, M. & Gates, B. C. Atomically dispersed supported metal catalysts. Ann. Rev. Chem. Bio. Eng. 3, 545–574 (2012).Gates, B. C. Supported metal clusters: synthesis, structure, and catalysis. Chem. Rev. 95, 511–522 (1995).Corma, A. et al. Exceptional oxidation activity with size-controlled supported gold clusters of low atomicity. Nat. Chem. 5, 775–781 (2013).Yang, M. et al. Catalytically active Au-O(OH)x-species stabilized by alkali ions on zeolites and mesoporous oxides. Science 346, 1498–1501 (2014).Rivallan, M. et al. Platinum sintering on H-ZSM-5 followed by chemometrics of CO adsorption and 2D pressure-jump IR spectroscopy of adsorbed species. Angew. Chem. Int. Ed. 49, 785–789 (2010).Zecevic, J., van der Eerden, A. M., Friedrich, H., de Jongh, P. E. & de Jong, K. P. Heterogeneities of the nanostructure of platinum/zeolite Y catalysts revealed by electron tomography. ACS Nano 7, 3698–3705 (2013).Philippaerts, A. et al. Unprecedented shape selectivity in hydrogenation of triacylglycerol molecules with Pt/ZSM-5 zeolite. Angew. Chem. Int. Ed. 50, 3947–3949 (2011).Kim, J., Kim, W., Seo, Y., Kim, J.-C. & Ryoo, R. n-Heptane hydroisomerization over Pt/MFI zeolite nanosheets: effects of zeolite crystal thickness and platinum location. J. Catalys. 301, 187–197 (2013).Goel, S., Wu, Z., Zones, S. I. & Iglesia, E. Synthesis and catalytic properties of metal clusters encapsulated within small-pore (SOD, GIS, ANA) zeolites. J. Am. Chem. Soc. 134, 17688–17695 (2012).Choi, M., Wu, Z. & Iglesia, E. Mercaptosilane-assisted synthesis of metal clusters within zeolites and catalytic consequences of encapsulation. J. Am. Chem. Soc. 132, 9129–9137 (2010).Choi, M., Yook, S. & Kim, H. Hydrogen spillover in encapsulated metal catalysts: new opportunities for designing advanced hydroprocessing catalysts. ChemCatChem 7, 1048–1057 (2015).Kulkarni, A., Lobo-Lapidus, R. J. & Gates, B. C. Metal clusters on supports: synthesis, structure, reactivity, and catalytic properties. Chem. Commun. 46, 5997–6015 (2010).Guzman, J. & Gates, B. C. Supported molecular catalysts: metal complexes and clusters on oxides and zeolites. Dalton Trans. 1, 3303–3318 (2003).Leonowicz, M. E., Lawton, J. A., Lawton, S. L. & Rubin, M. K. MCM-22: a molecular sieve with two independent multidimensional channel systems. Science 264, 1910–1913 (1994).Camblor, M. A. et al. A new microporous polymorph of silica isomorphous to zeolite MCM-22. Chem. Mater. 8, 2415–2417 (1996).Hyotanishi, M., Isomura, Y., Yamamoto, H., Kawasaki, H. & Obora, Y. Surfactant-free synthesis of palladium nanoclusters for their use in catalytic cross-coupling reactions. Chem. Commun. 47, 5750–5752 (2011).Duchesne, P. N. & Zhang, P. Local structure of fluorescent platinum nanoclusters. Nanoscale 4, 4199–4205 (2012).Lu, J., Aydin, C., Browning, N. D. & Gates, B. C. Imaging isolated gold atom catalytic sites in zeolite NaY. Angew. Chem. Int. Ed. 51, 5842–5846 (2012).Yacamán, M. J., Santiago, U. & Mejía-Rosales, S. in Advanced Transmission Electron Microscopy: Applications to Nanomaterials (eds Francis, L., Mayoral, A. & Arenal, R.) 1–29 (Springer, 2015).Jena, P., Khanna, S. N. & Rao, B. K. Physics and Chemistry of Finite Systems: From Clusters to Crystals (Springer, 1992).Yamasaki, J. et al. Ultramicroscopy 151, 224–231 (2015).Sohlberg, K., Pennycook, T. J., Zhoud, W. & Pennycook, S. J. Insights into the physical chemistry of materials from advances in HAADF-STEM. Phys. Chem. Chem. Phys. 17, 3982–4006 (2015).Aydin, C., Lu, J., Browning, N. D. & Gates, B. C. A ‘smart’ catalyst: sinter-resistant supported iridium clusters visualized with electron microscopy. Angew. Chem. Int. Ed. 51, 5929–5934 (2012).Wei, H. et al. FeOx-supported platinum single-atom and pseudo-single-atom catalysts for chemoselective hydrogenation of functionalized nitroarenes. Nat. Commun. 5, 5634 (2014).Addou, R. et al. Influence of hydroxyls on Pd atom mobility and clustering on rutile TiO2(011)-2 × 1. ACS Nano 8, 6321–6333 (2014).Jung, U. et al. Comparative in operando studies in heterogeneous catalysis: atomic and electronic structural features in the hydrogenation of ethylene over supported Pd and Pt catalysts. ACS Catal. 5, 1539–1551 (2015).Agostini, G. et al. Effect of different face centered cubic nanoparticle distributions on particle size and surface area determination: a theoretical study. J. Phys. Chem. C 118, 4085–4094 (2014).Alexeev, O. & Gates, B. C. EXAFS characterization of supported metal-complex and metal-cluster catalysts made from organometallic precursors. Top. Catal. 10, 273–293 (2000).Chakraborty, I., Bhuin, R. G., Bhat, S. & Pradeep, T. Blue emitting undecaplatinum clusters. Nanoscale 6, 8561–8564 (2014).Zheng, J., Nicovich, P. R. & Dickson, R. M. Highly fluorescent noble-metal quantum dots. Ann. Rev. Phys. Chem. 58, 409–431 (2007).Okrut, A. et al. Selective molecular recognition by nanoscale environments in a supported iridium cluster catalyst. Nat. Nanotech. 9, 459–465 (2014).Zhou, C. et al. On the sequential hydrogen dissociative chemisorption on small platinum clusters: a density functional theory study. J. Phys. Chem. C 111, 12773–12778 (2007).De La Cruz, C. & Sheppard, N. An exploration of the surfaces of some Pt/SiO2 catalysts using CO as an infrared spectroscopic probe. Spectrochim. Acta A 50, 271–285 (1994).Klünker, C., Balden, M., Lehwald, S. & Daum, W. CO stretching vibrations on Pt(111) and Pt(110) studied by sum frequency generation. Surf. Sci. 360, 104–111 (1996).Stakheev, A. Y., Shpiro, E. S., Jaeger, N. I. & Schulz-Ekloff, G. Electronic state and location of Pt metal clusters in KL zeolite: FTIR study of CO chemisorption. Catal. Lett. 32, 147–158 (1995).Heiz, U., Sanchez, A., Abbet, S. & Schneider, W. D. Catalytic oxidation of carbon monoxide on monodispersed platinum clusters: each atom counts. J. Am. Chem. Soc. 121, 3214–3217 (1999).Levitas, V. I. & Samani, K. Size and mechanics effects in surface-induced melting of nanoparticles. Nat. Commun. 2, 284 (2011).Jiang, H., Moon, K.-s., Dong, H., Hua, F. & Wong, C. P. Size-dependent melting properties of tin nanoparticles. Chem. Phys. Lett. 429, 492–496 (2006).Nanda, K. K., Kruis, F. E. & Fissan, H. Evaporation of free PbS nanoparticles: evidence of the Kelvin effect. Phys. Rev. Lett. 89, 256103 (2002).Vajda, S. et al. Subnanometre platinum clusters as highly active and selective catalysts for the oxidative dehydrogenation of propane. Nat. Mater. 8, 213–216 (2009).Ortalan, V., Uzun, A., Gates, B. C. & Browning, N. D. Direct imaging of single metal atoms and clusters in the pores of dealuminated HY zeolite. Nat. Nanotech. 5, 506–510 (2010).Koch, C. Determination of Core Structure Periodicity and Point Defect Density along Dislocations PhD thesis, Univ. Arizona (2002).Mathon, O. et al. The time-resolved and extreme conditions XAS (TEXAS) facility at the European Synchrotron Radiation Facility: the general-purpose EXAFS bending-magnet beamline BM23. J. Synchrotron Radiat. 22, 1548–1554 (2015).Newville, M. IFEFFIT: interactive XAFS analysis and FEFF fitting. J. Synchrotron Radiat. 8, 322–324 (2001)

    Resistance training in women with myotonic dystrophy type 1: A multisystemic therapeutic avenue

    Get PDF
    Abstract Myotonic dystrophy type 1 (DM1) is a hereditary disease characterized by muscular impairments. Fundamental and clinical positive effects of strength training have been reported in men with DM1, but its impact on women remains unknown. We evaluated the effects of a 12-week supervised strength training on physical and neuropsychiatric health. Women with DM1 performed a twice-weekly supervised resistance training program (3 series of 6–8 repetitions of squat, leg press, plantar flexion, knee extension, and hip abduction). Lower limb muscle strength, physical function, apathy, anxiety and depression, fatigue and excessive somnolence, pain, and patient-reported outcomes were assessed before and after the intervention, as well as three and six months after completion of the training program. Muscle biopsies of the vastus lateralis were also taken before and after the training program to assess muscle fiber growth. Eleven participants completed the program (attendance: 98.5 %). Maximal hip and knee extension strength (p < 0.006), all One-Repetition Maximum strength measures (p < 0.001), apathy (p = 0.0005), depression (p = 0.02), pain interference (p = 0.01) and perception of the lower limb function (p = 0.003) were significantly improved by training. Some of these gains were maintained up to six months after the training program. Strength training is a good therapeutic strategy for women with DM1
    corecore