182 research outputs found

    Langmuir-Blodgett Films of the Metal-Organic Framework MIL-101(Cr): Preparation, Characterization, and CO2 Adsorption Study Using a QCM-Based Setup

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    This work reports the fabrication and characterization of Langmuir–Blodgett films of nanoparticles (size 51 ± 10 nm) of the metal organic framework MIL-101(Cr). LB film characterization by SEM, UV–vis, GIXRD, and QCM has shown that the addition of 1 wt % of behenic acid to MOF dispersion allows obtaining dense monolayers at the air–water interface that can be deposited onto solid substrates of different nature with transfer ratios close to 1. Moreover, a QCM-based setup has been built and used for the first time to measure CO2 adsorption isotherms at 303 K on MOF LB films, proving that LB films with MOF masses between 1.2 (1 layer) and 2.3 (2 layers) ”g can be used to obtain accurate adsorption values at 100 kPa, similar to those obtained by conventional adsorption methods that require much larger MOF quantities (tens of milligrams)

    Policitemia vera en un perro : su diagnĂłstico y su tratamiento

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    En este artĂ­culo presentamos un caso clĂ­nico de policitemia vera (eritrocitosis) canina con un nivel de eritropoyetina en suero normal. Fue diagnosticado y tratado mediante flebotomĂ­as repetidas, en un primer momento y con hidroxyurea posteriormente

    The mediterranean biotypes of Tylenchulus semipenetrans in Spanish citrus orchards

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    Les capacités de reproduction de quatorze populations du nématode des citrus (#Tylenchulus semipenetrans$) collectées dans la principale zone de citriculture de l'Espagne ont été comparées sur oranger amer et citrange Carrizo. Toutes les populations ont été identifiées comme appartenant au biotype méditerranéen. La capacité de reproduction varie considérablement en fonction des populations. Le pouvoir infestant et le taux de reproduction des populations collectées dans la rhizosphÚre des porte-greffes citranges Troyer ou Carrizo sont plus élevés (P supérieur ou égal à 0,05) que ceux des populations collectées sur oranger amer. (Résumé d'auteur

    Synthesis and gas adsorption properties of mesoporous silica-NH2-MIL-53(Al) core-shell spheres

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    Ordered mesoporous silica-NH2-MIL-53(Al) core-shell spheres of about 4 ”m in diameter have been synthesized by seeding the corresponding mesoporous silica spheres (MSSs) with crystals of NH2-MIL-53(Al) and subsequent secondary crystal growth into a MOF shell. The morphology of the particles was analyzed by SEM, while TGA, EDX and XRD characterizations gave information on the composition and structure of this material and the activation of the MOF. N2 adsorption analysis revealed that the NH2-MIL-53(Al) shell controlled the access of guest molecules into the hydrophilic silica mesoporous structure, while the breathing behavior of the microporous NH2-MIL-53(Al) shell was confirmed by CO2 adsorption isotherms

    Fabrication of ultrathin films containing the metal organic framework Fe-MIL-88B-NH2 by the Langmuir-Blodgett technique

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    In this work, the fabrication of ultrathin films containing the metal organic framework (MOF) Fe-MIL- 88B-NH2 by the Langmuir–Blodgett (LB) technique has been explored. MOF crystals of two different sizes (1.5 ± 0.3 and 0.07 ± 0.01 ”m) have been synthesized and assembled at the air–liquid interface by the LB method. The effect of the subphase pH and particle size on the film formation process has been studied. Moreover, for the first time, mixed MOF+polymer (the commercial soluble polyimide MatrimidÂź) LB films containing different MOF loadings have been fabricated. These experiments show that it is possible to obtain ultrathin MOF + polymer films with a controlled MOF density. Furthermore, MOF particles are homogeneously distributed in the polymer matrix, even with very large amounts of MOF (up to 95 wt%). LB films have been incorporated into materials of different nature, including glass and mica substrates and also polymeric membranes based on polysulfone UdelÂź and PIM-1 (polymer of intrinsic microporosity), and the modification of water contact angle after LB film deposition has been analyzed

    Delayed gastric emptying after classical Whipple or pylorus-preserving pancreatoduodenectomy: a randomized clinical trial (QUANUPAD)

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    Purpose Pylorus-preserving pancreatoduodenectomy (PPPD) has been the gold standard for pancreatic head lesion resection for several years. Some studies have noted that it involves more delayed gastric emptying (DGE) than classical Whipple (i.e., pancreatoduodenectomy with antrectomy). Our working hypothesis was that the classical Whipple has a lower incidence of DGE. We aimed to compare the incidence of DGE among pancreatoduodenectomy techniques. Methods This pragmatic, randomized, open-label, single-center clinical trial involved patients who underwent classical Whipple (study group) or PPPD (control group). Gastric emptying was clinically evaluated using scintigraphy. DGE was defined according to the International Study Group of Pancreatic Surgery (ISGPS) criteria. The secondary endpoints were postoperative morbidity, length of hospital stay, anthropometric measurements, and nutritional status. Results A total of 84 patients were randomized (42 per group). DGE incidence was 50% (20/40, 95% confidence interval (95% CI): 35-65%) in the study group and 62% (24/39, 95% CI: 46-75%) in the control group (p = 0.260). No differences were observed between both groups regarding postoperative morbidity or length of hospital stay. Anthropometric measurements at 6 months post-surgery: triceps fold measurements were 12 mm and 16 mm (p = 0.021). At 5 weeks post-surgery, triceps fold measurements were 13 mm and 16 mm (p = 0.020) and upper arm circumferences were 26 cm and 28 cm (p = 0.030). No significant differences were observed in nutritional status. Conclusion DGE incidence and severity did not differ between classical Whipple and PPPD. Some anthropometric measurements may indicate a better recovery with PPPD

    On the sub-micron aerosol size distribution in a coastal-rural site at El Arenosillo Station (SW – Spain)

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    This study focuses on the analysis of the sub-micron aerosol characteristics at El Arenosillo Station, a rural and coastal environment in South-western Spain between 1 August 2004 and 31 July 2006 (594 days). The mean total concentration (<i>N</i><sub>T</sub>) was 8660 cm<sup>−3</sup> and the mean concentrations in the nucleation (<i>N</i><sub>NUC</sub>), Aitken (<i>N</i><sub>AIT</sub>) and accumulation (<i>N</i><sub>ACC</sub>) particle size ranges were 2830 cm<sup>−3</sup>, 4110 cm<sup>−3</sup> and 1720 cm<sup>−3</sup>, respectively. Median size distribution was characterised by a single-modal fit, with a geometric diameter, median number concentration and geometric standard deviation of 60 nm, 5390 cm<sup>−3</sup> and 2.31, respectively. Characterisation of primary emissions, secondary particle formation, changes to meteorology and long-term transport has been necessary to understand the seasonal and annual variability of the total and modal particle concentration. Number concentrations exhibited a diurnal pattern with maximum concentrations around noon. This was governed by the concentrations of the nucleation and Aitken modes during the warm seasons and only by the nucleation mode during the cold seasons. Similar monthly mean total concentrations were observed throughout the year due to a clear inverse variation between the monthly mean <i>N</i><sub>NUC</sub> and <i>N</i><sub>ACC</sub>. It was related to the impact of desert dust and continental air masses on the monthly mean particle levels. These air masses were associated with high values of <i>N</i><sub>ACC</sub> which suppressed the new particle formation (decreasing <i>N</i><sub>NUC</sub>). Each day was classified according to a land breeze flow or a synoptic pattern influence. The median size distribution for desert dust and continental aerosol was dominated by the Aitken and accumulation modes, and marine air masses were dominated by the nucleation and Aitken modes. Particles moved offshore due to the land breeze and had an impact on the particle burden at noon, especially when the wind was blowing from the NW sector in the morning during summer time. This increased <i>N</i><sub>NUC</sub> and <i>N</i><sub>AIT</sub> by factors of 3.1 and 2.4, respectively. Nucleation events with the typical "banana" shape were characterised by a mean particle nucleation rate of 0.74 cm<sup>−3</sup> s<sup>−1</sup>, a mean growth rate of 1.96 nm h<sup>−1</sup> and a mean total duration of 9.25 h (starting at 10:55 GMT and ending at 20:10 GMT). They were observed for 48 days. Other nucleation events were identified as those produced by the emissions from the industrial areas located at a distance of 35 km. They were observed for 42 days. Both nucleation events were strongly linked to the marine air mass origin

    TEMPORAL AND SPATIAL VARIABILITY OF ATMOSPHERIC PARTICLE NUMBER SIZE DISTRIBUTIONS ACROSS SPAIN

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    This study synthesizes for the first time results from simultaneous aerosol measurements performed at seven diverse locations distributed all over the Spanish geography. The observations were carried out during two field campaigns in 2012–2013, one-month each and during different seasons. These field campaigns were performed in the framework of the Spanish Network of DMAs (REDMAAS) activities. Measurement sites were grouped as polluted sites (urban background) and clean sites (rural background and high-altitude sites). Seasonal differences were more important at polluted sites, mainly related to meteorology and aerosol sources. Higher total particle concentrations were found during the cold period, driven mainly by Aitken-mode particles (traffic-related aerosol particles).This work has been financed by the Ministry of Science and Innovation (CGL2011-15008-E, CGL2010-1777, CGL2011-27020, CGL2014-52877-R, CGL2010-11095-E, CGL2012-39623-C02-01, CGL2014-55230-R & PI15/0051
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