178 research outputs found

    Competitive Adsorption and Diffusion of Gases in a Microporous Solid

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    The experimental and theoretical study of the co-adsorption and co-diffusion of several gases through a microporous solid and the instantaneous (out of equilibrium) distribution of the adsorbed phases is particularly important in many fields, such as gas separation, heterogeneous catalysis, purification of confined atmospheres, reduction of exhaust emissions contributing to global warming, etc. The original NMR imaging technique used gives a signal characteristic of each adsorbed gas at each instant and at each level of the solid and therefore the distribution of several gases in competitive diffusion and adsorption. But it does not allow to determine separately the inter- and intra-crystallite quantities. A new fast and accurate analytical method for the calculation of the coefficients of co-diffusing gases in the intra- and inter-crystallite spaces of microporous solid (here ZSM 5 zeolite) is developed, using high-performance methods (iterative gradient methods of residual functional minimization and analytical methods of influence functions) and mathematical co-adsorption models, as well as the NMR spectra of each adsorbed gas in the bed. These diffusion coefficients and the gas concentrations in the inter- and intra-crystallite spaces are obtained for each position in the bed and for different adsorption times

    Universality and the Renormalisation Group

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    Several functional renormalisation group (RG) equations including Polchinski flows and Exact RG flows are compared from a conceptual point of view and in given truncations. Similarities and differences are highlighted with special emphasis on stability properties. The main observations are worked out at the example of O(N) symmetric scalar field theories where the flows, universal critical exponents and scaling potentials are compared within a derivative expansion. To leading order, it is established that Polchinski flows and ERG flows - despite their inequivalent derivative expansions - have identical universal content, if the ERG flow is amended by an adequate optimisation. The results are also evaluated in the light of stability and minimum sensitivity considerations. Extensions to higher order and further implications are emphasized.Comment: 15 pages, 2 figures; paragraph after (19), figure 2, and references adde

    THERMAL ACTIVATED CARRIER TRANSFER BETWEEN InAs QUANTUM DOTS IN VERY LOW DENSITY SAMPLES

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    During the last decade, a great effort has been made studying the temperature evolution of QD emission, obtaining good agreements between experimental data and theoretical models. Thermal escape through wetting layer (WL) or by phonon assisted tunneling is usually claimed to describe carrier transfer in monomodal and bimodal QDs distributions. In the present study we have analyzed this phenomenon in two different samples containing a very low density of InAs/GaAs QDs, namely 16.5 and 25 QD/?m2 (Samples I and II, respectively). A detailed experimental study as a function of temperature has been carried out by using ensemble photoluminescence (PL), micro-PL and time resolved PL (TRPL) techniques. In both samples coexist two QD size distributions: (i) a small size one emitting in the region 1.25-1.35 eV (SQD family) and (ii) a large size one emitting in the region 1.05-1.20 eV (LQD family), as shown in Figs. 1.a-b. In sample I the SQD family dominates in intensity and the opposite is observed in Sample II, yet their temperature evolution is similar. An increase of the LQD integrated intensity is observed simultaneously with the decrease of the SDQ band, as observed in Figs. 1.c-d. This behavior is corroborated by the first time by Micro-PL of single QDs (see Fig. 1.e) belonging to both families detected simultaneously. The experiment is performed by using a multimode optical fiber in the detection arm of our confocal microscope and a monomode optical fiber to excite the SQD. A set of balance equations is used to reproduce the measured temperature evolution of the whole PL spectrum by introducing the transfer between SQD towards neighbor LQDs via WL states and the measured TRPL data

    MHC-B variation in maternal and paternal synthetic lines of the Argentinian Campero INTA chicken

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    The Campero-INTA chicken of Argentina was developed to provide a robust bird that can survive under Argentinian pasture conditions with no significant additional nutrition, producing a source of animal protein for small producers or low-income families. In previous work we described the AH paternal line of Campero and its Major Histocompatibility Complex B region (MHC-B) variation. In this work we analyzed the three remaining synthetic lines used to produce the Campero-INTA production bird: lines AS, A and E. Because of the association between variation within the MHC of chickens and disease resistance, MHC variation within this breed is of particular interest. MHC variability within the lines used to produce the Campero-INTA chicken was examined using a 90 SNP panel encompassing the chicken MHC-B region plus the VNTR, LEI0258, located within the chicken MHC. Across all four lines 12 haplotypes were found, with 7 of these being previously reported in North America/European breeds, reflecting the original breed sources for these birds. Three Campero unique haplotypes were found, two of which likely originated from MHC recombination events. MHC-B variation for all lines involved with production of the final Campero-INTA bird have now been determined.EEA PergaminoFil: Iglesias, Gabriela M. Universidad Nacional de Río Negro. Sede Alto Valle y Valle Medio. Escuela de Veterinaria y Producción Agroindustrial. Cátedra de Genética; ArgentinaFil: Beker, María P. Universidad Nacional de Río Negro. Sede Alto Valle y Valle Medio. Escuela de Veterinaria y Producción Agroindustrial. Cátedra de Genética; ArgentinaFil: Remolins, José S. Universidad Nacional de Río Negro. Sede Alto Valle y Valle Medio. Escuela de Veterinaria y Producción Agroindustrial. Cátedra de Genética; ArgentinaFil: Canet, Zulma Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Sección Avicultura; ArgentinaFil: Canet, Zulma Edith. Universidad Nacional de Rosario. Facultad de Ciencias Veterinaria. Cátedra de Genética; ArgentinaFil: Librera, José. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Genética; ArgentinaFil: Cantaro, Horacio Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Cantaro, Horacio Luis. Universidad Nacional de Río Negro. Sede Alto Valle y Valle Medio. Escuela de Veterinaria y Producción Agroindustrial. Cátedra de Genética; ArgentinaFil: Maizon, Daniel Omar Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Fulton, Janet E. Hy-Line International; Estados Unido

    Laves intermetallics in stainless steel–zirconium alloys

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    Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nuclear fuel by electrometallurgical treatment. The baseline waste form composition for stainless steel-clad fuels is stainless steel-15 wt.% zirconium (SS-15Zr). This article presents results of neutron diffraction measurements, heat-treatment studies and mechanical testing on SS-15Zr alloys. The Laves intermetallics in these alloys, labeled Zr(Fe,Cr,Ni){sub 2+x}, have both C36 and C15 crystal structures. A fraction of these intermetallics transform into (Fe,Cr,Ni){sub 23}Zr{sub 6} during high-temperature annealing; the authors have proposed a mechanism for this transformation. The SS-15Zr alloys show virtually no elongation in uniaxial tension, but exhibit good strength and ductility in compression tests. This article also presents neutron diffraction and microstructural data for a stainless steel-42 wt.% zirconium (SS-42Zr) alloy

    Interferon-Gamma Release Assays Differentiate between Mycobacterium avium Complex and Tuberculous Lymphadenitis in Children

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    Spanish Pediatric TB Research Network (pTBred) and the European NontuberculouS MycoBacterial Lymphadenitis in childrEn (ENSeMBLE) Study.[Objectives] To assess the performance of interferon-gamma release assays (IGRAs) in the differential diagnosis between Mycobacterium avium complex (MAC) and tuberculosis (TB) in children affected with subacute/chronic submandibular/cervical lymphadenitis.[Study design] Multicenter observational study comparing children with microbiologically confirmed MAC lymphadenitis from the European NontuberculouS MycoBacterial Lymphadenitis in childrEn study with children with TB lymphadenitis from the Spanish Network for the Study of Pediatric TB database.[Results] Overall, 78 patients with MAC and 34 with TB lymphadenitis were included. Among MAC cases, 44 out of 74 (59.5%) had positive tuberculin skin test (TST) results at the 5-mm cut-off, compared with 32 out of 33 (97%) TB cases (P < .001); at the 10-mm cut-off TST results were positive in 23 out of 74 (31.1%) vs 26 out of 31 (83.9%), respectively (P < .001). IGRA results were positive in only 1 out of 32 (3.1%) patients with MAC who had undergone IGRA testing, compared with 21 out of 23 (91.3%) TB cases (P < .001). Agreement between TST and IGRA results was poor in MAC (23.3%; κ = 0.017), but good in TB cases (95.6%; κ = 0.646). IGRAs had a specificity of 96.9% (95% CI 84.3%-99.8%), positive predictive value of 95.4% (95% CI 78.2%-99.8%), and negative predictive value of 93.9% (95% CI 80.4%-98.9%) for TB lymphadenitis.[Conclusions] In contrast to TST, IGRAs have high specificity, negative predictive value, and positive predictive value for TB lymphadenitis in children with subacute/chronic lymphadenopathy, and consequently can help to discriminate between TB and MAC disease. Therefore, IGRAs are useful tools in the diagnostic work-up of children with lymphadenopathy, particularly when culture and polymerase chain reaction results are negative.Peer reviewe

    Primary constitutional MLH1 epimutations: a focal epigenetic event

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    BACKGROUND: Constitutional MLH1 epimutations are characterised by monoallelic methylation of the MLH1 promoter throughout normal tissues, accompanied by allele-specific silencing. The mechanism underlying primary MLH1 epimutations is currently unknown. The aim of this study was to perform an in-depth characterisation of constitutional MLH1 epimutations targeting the aberrantly methylated region around MLH1 and other genomic loci. METHODS: Twelve MLH1 epimutation carriers, 61 Lynch syndrome patients, and 41 healthy controls, were analysed by Infinium 450 K array. Targeted molecular techniques were used to characterise the MLH1 epimutation carriers and their inheritance pattern. RESULTS: No nucleotide or structural variants were identified in-cis on the epimutated allele in 10 carriers, in which inter- generational methylation erasure was demonstrated in two, suggesting primary type of epimutation. CNVs outside the MLH1 locus were found in two cases. EPM2AIP1-MLH1 CpG island was identified as the sole differentially methylated region in MLH1 epimutation carriers compared to controls. CONCLUSION: Primary constitutional MLH1 epimutations arise as a focal epigenetic event at the EPM2AIP1-MLH1 CpG island in the absence of cis-acting genetic variants. Further molecular characterisation is needed to elucidate the mechanistic basis of MLH1 epimutations and their heritability/reversibility

    Cuidados Intensivos de Anestesia: recomendaciones de la Sección de Cuidados Intensivos de la SEDAR: Monedero P, Paz Martín D, Cardona Pereto J, Barturen F, Fernández Quero L, Aguilera Celorrio L, et al. Cuidados Intensivos de Anestesia: recomendaciones de la Sección de Cuidados Intensivos de la SEDAR. Rev Esp Anestesiol Reanim. 2017;64(5):282-285. doi: 10.1016/j.redar.2016.12.007. PMID: 28258746

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    Las directrices europeas de formación especializada en Anestesiología son responsabilidad del European Board of Anaesthesiology (EBA UEMS), a través de su comité permanente de Educación y Desarrollo Profesional. Estas directrices han sido aprobadas por el UEMS Council, y en ellas se definen los cuidados intensivos como una competencia central de la especialidad de Anestesiología. A diferencia de otras competencias específicas, la «atención médica y perioperatoria de pacientes críticos/Cuidados Intensivos Generales» es considerada un dominio de competencias básicas que debe alcanzar todo especialista en Anestesiología en Europa. Para alcanzar el conjunto de competencias de la especialidad, las «Normas europeas de formación postgrado de especialistas médicos» en sus «Requisitos de Capacitación para la Especialidad de Anestesiología, Dolor y Medicina de Cuidados Intensivos» establece un tiempo mínimo de formación de 5 años, de los cuales hasta un año puede dirigirse específicamente a la formación en Medicina de Cuidados Intensivos
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