690 research outputs found

    In vivo endoscopic autofluorescence microspectro-imaging of bronchi and alveoli

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    Fibered confocal fluorescence microscopy (FCFM) is a new technique that can be used during a bronchoscopy to analyze the nature of the human bronchial and alveolar mucosa fluorescence microstructure. An endoscopic fibered confocal fluorescence microscopy system with spectroscopic analysis capability was developed allowing real-time, simultaneous images and emission spectra acquisition at 488 nm excitation using a flexible miniprobe that could be introduced into small airways. This flexible 1.4 mm miniprobe can be introduced into the working channel of a flexible endoscope and gently advanced through the bronchial tree to the alveoli. FCFM in conjunction with bronchoscopy is able to image the in vivo autofluorescence structure of the bronchial mucosae but also the alveolar respiratory network outside of the usual field of view. Microscopic and spectral analysis showed that the signal mainly originates from the elastin component of the bronchial subepithelial layer. In non smokers, the system images the elastin backbone of the aveoli. In active smokers, a strong autofluorescence signal appears from alveolar macrophages. The FCFM technique appears promising for in vivo exploration of the bronchial and alveolar extracellular matrix

    Effects of NHC-Backbone Substitution on Efficiency in Ruthenium-Based Olefin Metathesis

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    series of ruthenium olefin metathesis catalysts bearing N-heterocyclic carbene (NHC) ligands with varying degrees of backbone and N-aryl substitution have been prepared. These complexes show greater resistance to decomposition through C−H activation of the N-aryl group, resulting in increased catalyst lifetimes. This work has utilized robotic technology to examine the activity and stability of each catalyst in metathesis, providing insights into the relationship between ligand architecture and enhanced efficiency. The development of this robotic methodology has also shown that, under optimized conditions, catalyst loadings as low as 25 ppm can lead to 100% conversion in the ring-closing metathesis of diethyl diallylmalonate

    Fermi Surface of Alpha-Uranium at Ambient Pressure

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    We have performed de Haas-van Alphen measurements of the Fermi surface of alpha-uranium single crystals at ambient pressure within the alpha-3 charge density wave (CDW) state from 0.020 K - 10 K and magnetic fields to 35 T using torque magnetometry. The angular dependence of the resulting frequencies is described. Effective masses were measured and the Dingle temperature was determined to be 0.74 K +/- 0.04 K. The observation of quantum oscillations within the alpha-3 CDW state gives new insight into the effect of the charge density waves on the Fermi surface. In addition we observed no signature of superconductivity in either transport or magnetization down to 0.020 K indicating the possibility of a pressure-induced quantum critical point that separates the superconducting dome from the normal CDW phase.Comment: 11 pages, 4 figures, 3 table

    Pressure Evolution of a Field Induced Fermi Surface Reconstruction and of the Neel Critical Field in CeIn3

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    We report high-pressure skin depth measurements on the heavy fermion material CeIn3 in magnetic fields up to 64 T using a self-resonant tank circuit based on a tunnel diode oscillator. At ambient pressure, an anomaly in the skin depth is seen at 45 T. The field where this anomaly occurs decreases with applied pressure until approximately 1.0 GPa, where it begins to increase before merging with the antiferromagnetic phase boundary. Possible origins for this transport anomaly are explored in terms of a Fermi surface reconstruction. The critical magnetic field at which the Neel ordered phase is suppressed is also mapped as a function of pressure and extrapolates to the previous ambient pressure measurements at high magnetic fields and high pressure measurements at zero magnetic field.Comment: 15 pages, 5 figure

    Role of dimensionality in the Kondo CeT X-2 family: the case of CeCd0.7Sb2

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORMotivated by the presence of competing magnetic interactions in the heavy fermion family CeT X-2 (T = transition metal, X = pnictogen), here we study the novel parent compound CeCd0.7Sb2 by combining magnetization, electrical resistivity, and heat-capacity measurements. Contrary to the antiferromagnetic (AFM) ground state observed in most members of this family, the magnetic properties of our CeCd0.7Sb2 single crystals revealed a ferromagnetic ordering at T-c = 3 K with an unusual soft behavior. By using a mean field model including anisotropic nearest-neighbor interactions and the tetragonal crystalline electric field (CEF) Hamiltonian, a systematic analysis of our macroscopic data was obtained. Our fits allowed us to extract a simple but very distinct CEF scheme, as compared to the AFM counterparts. As in the previously studied ferromagnet CeAgSb2, a pure vertical bar +/- 1/2 > ground state is realized, hinting at a general trend within the ferromagnetic members. More generally, we propose a scenario for the understanding of the magnetism in this family of compounds based on the subtle changes of dimensionality in the crystal structure.Motivated by the presence of competing magnetic interactions in the heavy fermion family CeT X-2 (T = transition metal, X = pnictogen), here we study the novel parent compound CeCd0.7Sb2 by combining magnetization, electrical resistivity, and heat-capacity measurements. Contrary to the antiferromagnetic (AFM) ground state observed in most members of this family, the magnetic properties of our CeCd0.7Sb2 single crystals revealed a ferromagnetic ordering at T-c = 3 K with an unusual soft behavior. By using a mean field model including anisotropic nearest-neighbor interactions and the tetragonal crystalline electric field (CEF) Hamiltonian, a systematic analysis of our macroscopic data was obtained. Our fits allowed us to extract a simple but very distinct CEF scheme, as compared to the AFM counterparts. As in the previously studied ferromagnet CeAgSb2, a pure vertical bar +/- 1/2 > ground state is realized, hinting at a general trend within the ferromagnetic members. More generally, we propose a scenario for the understanding of the magnetism in this family of compounds based on the subtle changes of dimensionality in the crystal structure.921316FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP [2013/17427-7, 2013/20181-0, 2012/04870-7]2012/04870-7, 2013/17427-7, 2013/20181-0Sem informaçãoSem informaçã

    Enhancing shopping experiences in smart retailing

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    The retailing market has undergone a paradigm-shift in the last decades, departing from its traditional form of shopping in brick-and-mortar stores towards online shopping and the establishment of shopping malls. As a result, “small” independent retailers operating in urban environments have suffered a substantial reduction of their turnover. This situation could be presumably reversed if retailers were to establish business “alliances” targeting economies of scale and engage themselves in providing innovative digital services. The SMARTBUY ecosystem realizes the concept of a “distributed shopping mall”, which allows retailers to join forces and unite in a large commercial coalition that generates added value for both retailers and customers. Along this line, the SMARTBUY ecosystem offers several novel features: (i) inventory management of centralized products and services, (ii) geo-located marketing of products and services, (iii) location-based search for products offered by neighboring retailers, and (iv) personalized recommendations for purchasing products derived by an innovative recommendation system. SMARTBUY materializes a blended retailing paradigm which combines the benefits of online shopping with the attractiveness of traditional shopping in brick-and-mortar stores. This article provides an overview of the main architectural components and functional aspects of the SMARTBUY ecosystem. Then, it reports the main findings derived from a 12 months-long pilot execution of SMARTBUY across four European cities and discusses the key technology acceptance factors when deploying alike business alliances

    Ready, Set, BABY Live Virtual Prenatal Breastfeeding Education for COVID-19

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    The COVID-19 pandemic has introduced unforeseen challenges in the delivery of lactation training, education, and skilled support worldwide. The World Health Organization (WHO) has developed global recommendations for the protection, promotion, and support of breastfeeding when COVID-19 is suspected or confirmed (World Health Organization, 2020). This interim guidance, which is grounded in the best available clinical evidence and epidemiology, brings attention to the importance of integrating breastfeeding education and skilled lactation support into the COVID-19 pandemic response (Gribble, 2018; UNICEF, 2020)

    Partitioning and transmutation strategy R&D for nuclear spent fuel: the SACSESS and GENIORS projects

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    Processes such as PUREX allow the recovery and reuse of the uranium and the plutonium of GEN II/GEN III reactors and are being adapted for the recycling of the uranium and the plutonium of GEN IV MOX fuels. However, it does not fix the sensitive issue of the long-term management of the high active nuclear waste (HAW). Indeed, only the recovery and the transmutation of the minor actinides can reduce this burden down to a few hundreds of years. In this context, and in the continuity of the FP7 EURATOM SACSESS project, GENIORS focuses on the reprocessing of MOX fuel containing minor actinides, taking into account safety issues under normal and mal-operation. By implementing a three-step approach (reinforcement of the scientific knowledge => process development and testing => system studies, safety and integration), GENIORS will provide more science-based strategies for nuclear fuel management in the EU
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