Conventional X-ray powder diffraction analyses of aluminum-substituted lithium nickel oxides showed pronounced broadening of the (11l) type peaks with increasing aluminum concentrations. It was ...postulated that a segregation tendency of nickel and aluminum in the layered lithium nickel oxide structure could lead to anisotropic strains and size effects for the (110) type planes and thus pronounced broadening. Variation in the distribution of aluminum and nickel was detected among different crystals by energy-dispersive X-ray spectroscopy (EDX) and within individual crystals at the nanometer-scale by electron energy loss spectroscopy (EELS). Synchrotron X-ray powder diffraction analyses of the “LiNi1−y Al y O2” (0.10 ≤ y ≤ 0.50) samples revealed that strains in the (110) planes continuously increased with the aluminum concentration, which was then confirmed by convergent beam and selected area electron diffraction studies. Therefore, a combination of synchrotron X-ray powder diffraction, electron diffraction, EDX, and EELS analyses provided, for the first time, direct evidence for the segregation tendency of nickel and aluminum in the layered lithium nickel oxide structure, from which a domain microstructure for the “LiNi0.50Al0.50O2” sample was proposed.
Dyskinésie des cordes vocales et/ou asthme Braun, J.J.; Delmas, C.; Charloux, A. ...
Revue française d'allergologie (2009),
April 2018, 2018-04-00, Letnik:
58, Številka:
3
Journal Article
Recenzirano
La dyskinésie des cordes vocales ou dysfonctionnement des cordes vocales (DCV) est caractérisée par une adduction paradoxale intermittente des cordes vocales à l’origine d’une obstruction ...fonctionnelle de la glotte, sans atteinte laryngée organique. Elle peut être isolée ou associée à un asthme. Sa physiopathologie complexe demeure mal connue et le diagnostic reste difficile.
Étude rétrospective de 15 cas de DCV (8 cas de DCV isolée et 7 cas de DCV avec asthme associé) avec analyse de la symptomatologie clinique et de la méthodologie diagnostique.
La symptomatologie associe de façon variable dyspnée laryngée avec stridor, sifflements laryngés, tirage et d’autres signes plus atypiques avec parfois perte de connaissance ou dyspnée aiguë nécessitant intubation, ventilation mécanique voire trachéotomie.
Le gold standard diagnostique est l’examen ORL laryngé tant pour le diagnostic différentiel que pour la mise en évidence de l’adduction paradoxale des cordes vocales lors de l’épisode aigu ou lors d’un test de provocation par exposition aux facteurs déclenchants habituels.
Le diagnostic de DCV reste difficile et probablement sous-évalué. Il concerne les médecins urgentistes, les pneumologues et les ORL pour un diagnostic précoce limitant la morbidité et le coût liés aux traitements inutiles et à l’errance diagnostique fréquente.
A series of “Li1+z/2(Ni0.425Mn0.425Co0.15)1−z/2O2−zFz” materials was prepared by a coprecipitation route and their structure was characterized using X-ray diffraction (XRD), as well as 7Li and 19F ...Magic Angle Spinning (MAS) NMR spectroscopy. Two hypotheses were considered: (i) formation of layered oxyfluoride materials and (ii) formation of a mixture between the layered material and LiF. Structural parameters were refined by the Rietveld method, using XRD diffraction data. The refinement results did not allow us to choose between these two hypotheses: no significant change in crystallinity and structural parameters was observed irrespective of the fluorine ratio. 7Li and 19F MAS NMR analyses showed signals with isotropic positions characteristic of LiF, but envelopes characteristic of very strong dipolar interactions with the electron spins of the material, demonstrating that LiF was not incorporated into the layered oxide structure but was instead present as a coating.
Les hospitalisations pour asthme sont considérées comme en grande partie évitables grâce à une prise en charge adaptée. L’objectif de cette étude était de décrire, à partir de la base nationale du ...programme de médicalisation des systèmes d’information (PMSI), les hospitalisations pour asthme de l’enfant.
Les séjours survenus entre 2002 et 2010 chez des enfants (âge<15ans) résidant en France (Guyane exclue) et ayant un diagnostic principal d’asthme ou d’asthme aigu grave, ou d’insuffisance respiratoire aiguë (IRA) avec en diagnostic associé un code d’asthme ou d’asthme aigu grave ont été sélectionnés.
En 2010, 35 004 séjours pour asthme et 1381 séjours pour IRA associée à un asthme ont été enregistrés (taux d’hospitalisation : 30,1/10 000 enfants) ; la durée moyenne des séjours avait été de 2j. Le taux de létalité intra-hospitalière avait été de 0,01 % à 0,03 % selon l’année. Le taux annuel d’hospitalisation standardisé sur l’âge avait augmenté entre 2002 et 2010 (+2,5 % par an en moyenne en France métropolitaine). En 2010, 11,8 % des enfants hospitalisés pour asthme ou pour IRA associée à un asthme avaient été réadmis pour ces mêmes motifs au moins une fois au cours de la même année, et 1,3 % dans les 7j. La proportion d’enfants de moins de 5ans réadmis au cours de la même année calendaire avait augmenté entre 2002 et 2010.
L’augmentation des taux d’hospitalisation et de réadmission témoigne d’une prise en charge non optimale de l’asthme chez l’enfant en France.
Most hospital admissions for asthma exacerbation are avoidable with adequate disease management. The objective of this study was to describe admissions for asthma in children in France using data from the French nationwide hospital database.
We selected admissions having either a main diagnosis of asthma or a main diagnosis of acute respiratory failure (ARF) with asthma as an associated diagnosis, occurring in children (age<15years) between 2002 and 2010 in France (excluding French Guyana).
In 2010, 35,004 asthma admissions and 1381 cases of asthma-related ARF were recorded (crude admission rate, 30.1/10,000 children); the mean length of stay was 2days. The in-hospital lethality rate ranged from 0.01% to 0.03% depending on the year. The annual age-standardized admission rate increased between 2002 and 2010 (+2.5% per year on average in metropolitan France). In 2010, 11.8% of children admitted for asthma or asthma-related ARF were readmitted for asthma or asthma-related ARF at least once within the same calendar year, and 1.3% were readmitted within the week following admission. The proportion of children aged less than 5 years who were readmitted within the same calendar year increased between 2002 and 2010.
The increase in admission and readmission rates indicates non-optimal management of asthma in children in France.
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The usefulness of the aryl halide, 4-bromopyrido-24-crown-8, in easily appending the pyrido-24-crown-8 unit onto organic frameworks to afford new dibenzylammonium receptors has been ...explored. Bromopyrido-24-crown-8 has been coupled with phenylboronic acid to yield 4-phenylpyrido-24-crown-8, which is shown to complex a variety of dibenzylammonium ions yielding complexes that are more stable than their dibenzo-24-crown-8 counterparts. One of these new complexes, in which a diformyl-terminated thread is bound, has been used to assemble a 2rotaxane under thermodynamic control.
► First test of ‘NMCA’, an alternative material to the currently commercial ones (NCA). ► Promising results in power tests at 30°C and −20°C. ► Structural stability after long range cycling at 40°C ...and 20°C in a small potential window. ► Significantly improved thermal stability vs. industrial NCA.
Li1.11(Ni0.40Mn0.39Co0.16Al0.05)0.89O2 was synthesized through coprecipitation of a mixed hydroxide followed by calcination with LiOH·H2O during 10h at 500°C and 950°C. Electrochemical tests and their comparison with those obtained for an industrial Li(Ni1−y−zCoyAlz)O2 material reveal that Li1.11(Ni0.40Mn0.39Co0.16Al0.05)0.89O2 shows good charge–discharge performance, even at high rate according to a protocol well established by car-makers for testing power abilities of batteries for electric and hybrid electric vehicles. In addition, this material shows a significant improvement in thermal stability in the highly deintercalated state (charged state of the battery) over the industrial material. Equivalent (or higher) energy and power densities with a significantly greater thermal stability make of Li1.11(Ni0.40Mn0.39Co0.16Al0.05)0.89O2 an interesting candidate as positive electrode material for large lithium-ion batteries.
