36 research outputs found
Analytical and experimental study of electrical conductivity in the lithium tantalate nonstoichiometric structure
We have been interested to experimental and analytical studies of ionic conductivity of nonstoichiometric LiTaO3 solid solutions. Theoretical approach combined with lithium and tantalate vacancy models has been performed. A comparative study between the calculated and measured values is presented taking into account the temperature and composition effects on the conductivity.We have been interested to experimental and analytical studies of ionic conductivity of nonstoichiometric LiTaO3 solid solutions. Theoretical approach combined with lithium and tantalate vacancy models has been performed. A comparative study between the calculated and measured values is presented taking into account the temperature and composition effects on the conductivity
Analyse fractale par morceaux de radiographies osseuses
- L'objectif de cette Ă©tude est de proposer, Ă partir du mouvement brownien fractionnaire (fBm) de paramĂštre H, un modĂšle plus gĂ©nĂ©ral qui puisse englober des phĂ©nomĂšnes prĂ©sentant un caractĂšre fractal par morceaux lors d'une analyse en frĂ©quence. Ce nouveau modĂšle est appelĂ© pfBm de paramĂštres Ho en basse frĂ©quence, Hi en haute frĂ©quence, ces deux rĂ©gimes Ă©tant sĂ©parĂ©s par une frĂ©quence de coupure Îł. Pour Ho=Hi=H, le pfBm se rĂ©duit au fBm, lui mĂȘme Ă©tant le mouvement brownien pour H=0.5. Nous pensons que le pfBm fournit ainsi un outil plus flexible que le fBm pour l'expĂ©rimentateur. Nous avons montrĂ© que ce processus a des incrĂ©ments stationnaires et qu'il est autosimilaire de paramĂštre Ho pour les basses frĂ©quences et de paramĂštre Hi pour les hautes frĂ©quences. Nous avons alors Ă©tudiĂ© des radiographies trabĂ©culaires osseuses qui prĂ©sentent ce caractĂšre bifractal. Les rĂ©sultats montrent que l'analyse fractale par morceaux est plus efficace que l'analyse fractale standard pour diagnostiquer les modifications de la micro-architecture osseuse liĂ©es Ă l'ostĂ©oporose
Caractérisation de milieux poreux par étude de leur géométrie 3D : Application à l'os trabéculaire
Cette communication présente le développement d'un ensemble d'outils permettant de caractériser un milieu poreux tel que l'os trabéculaire. Ce travail est basé sur une nouvelle technique permettant de localiser et d'individualiser les arches du milieu poreux. Nous nous intéressons principalement à la mesure d'anisotropie en 3 dimensions et au calcul d'indices d'orientation et de courbure pour chaque travée. Les différentes techniques mises en place sont comparées sur 2 populations différentes composées d'échantillons osseux ostéoporotiques et coxarthriques. Nous montrons que seuls les indices de courbure des travées permettent de discriminer de maniÚre significative les 2 populations étudiées
Polya's inequalities, global uniform integrability and the size of plurisubharmonic lemniscates
First we prove a new inequality comparing uniformly the relative volume of a
Borel subset with respect to any given complex euclidean ball \B \sub \C^n
with its relative logarithmic capacity in \C^n with respect to the same ball
\B.
An analoguous comparison inequality for Borel subsets of euclidean balls of
any generic real subspace of \C^n is also proved.
Then we give several interesting applications of these inequalities.
First we obtain sharp uniform estimates on the relative size of \psh
lemniscates associated to the Lelong class of \psh functions of logarithmic
singularities at infinity on \C^n as well as the Cegrell class of
\psh functions of bounded Monge-Amp\`ere mass on a hyperconvex domain \W
\Sub \C^n.
Then we also deduce new results on the global behaviour of both the Lelong
class and the Cegrell class of \psh functions.Comment: 25 page
Relation entre la régularité de fractals 3D et celle de leurs projections 2D. Application à l'os trabéculaire
Deux des auteurs ont rĂ©cemment Ă©tabli que la rĂ©gularitĂ© Rn d'un fractal continu isotrope de dimension n (nD) est Ă©gale Ă celle sa projection Rn-1 dans un espace (n-1)D diminuĂ©e de 0.5, ou plus clairement, Rn = Rn-1 - 0.5. Dans un premier temps, l'objectif de cette Ă©tude est d'expliquer briĂšvement ce rĂ©sultat et de l'illustrer sur des volumes fractals synthĂ©tiques, continus et binaires, et leurs projections. Pour les fractals continus, les rĂ©sultats sont proches de eux qu'il convient de trouver pour H faible. Pour H Ă©levĂ©, il apparaĂźt des difficultĂ©s liĂ©es essentiellement aux dĂ©fauts de la mĂ©thode de synthĂšse retenue. Pour les fractals binaires, l'Ă©cart de 0.5 qu'il est possible de trouver entre la rĂ©gularitĂ© du volume et celle de sa projection n'est pas clairement Ă©tablie. Dans un deuxiĂšme temps, nous avons expĂ©rimentalement Ă©tudiĂ© si cette relation est valide pour l'os trabĂ©culaire et sa projection. Nous avons analysĂ© 22 Ă©chantillons de tĂȘte de fĂ©mur imagĂ©s par micro-scanner. Nous trouvons une diffĂ©rence entre la rĂ©gularitĂ© 2D et celle en 3D de 0.53 ± 0.046. Ceci indique que le la relation qui lie la rĂ©gularitĂ© 3D d'un volume fractal Ă celle de sa projection s'applique pour cet objet binaire. Une simple mesure 2D permettrait alors de quantifier la structure trabĂ©culaire 3D et pourrait se rĂ©vĂ©ler d'une grande force pour le diagnostic prĂ©coce de l'ostĂ©oporose
mRNA accumulation in the Cajal bodies of the diplotene larch microsporocyte
In microsporocytes of the European larch, we demonstrated the presence of several mRNAs in spherical nuclear bodies. In the nuclei of microsporocytes, we observed up to 12 bodies, ranging from 0.5 to 6 Όm in diameter, during the prophase of the first meiotic division. Our previous studies revealed the presence of polyadenylated RNA (poly(A) RNA) in these bodies, but did not confirm the presence of nascent transcripts or splicing factors of the SR family. The lack of these molecules precludes the bodies from being the sites of synthesis and early maturation of primary transcripts (KoĆowerzo et al., Protoplasma 236:13â19, 2009). However, the bodies serve as sites for the accumulation of splicing machinery, including the Sm proteins and small nuclear RNAs. Characteristic ultrastructures and the molecular composition of the nuclear bodies, which contain poly(A) RNA, are indicative of Cajal bodies (CBs). Here, we demonstrated the presence of several housekeeping gene transcriptsâα-tubulin, pectin methylesterase, peroxidase and catalase, ATPase, and inositol-3-phosphate synthaseâin CBs. Additionally, we observed transcripts of the RNA polymerase II subunits RPB2 and RPB10 RNA pol II and the core spliceosome proteins mRNA SmD1, SmD2, and SmE. The co-localization of nascent transcripts and mRNAs indicates that mRNA accumulation/storage, particularly in CBs, occurs in the nucleus of microsporocytes
Gonadectomy in conditions affecting sex development: a registry-based cohort study
Objectives
To determine trends in clinical practice for individuals with DSD requiring gonadectomy.
Design
Retrospective cohort study.
Methods
Information regarding age at gonadectomy according to diagnosis; reported sex; time of presentation to specialist centre; and location of centre from cases reported to the International DSD Registry and who were over 16 years old in January 2019.
Results
Data regarding gonadectomy were available in 668 (88%) individuals from 44 centres. Of these, 248 (37%) (median age (range) 24 (17, 75) years) were male and 420 (63%) (median age (range) 26 (16, 86) years) were female. Gonadectomy was reported from 36 centres in 351/668 cases (53%). Females were more likely to undergo gonadectomy (nâ= 311, Pâ< 0.0001). The indication for gonadectomy was reported in 268 (76%). The most common indication was mitigation of tumour risk in 172 (64%). Variations in the practice of gonadectomy were observed; of the 351 cases from 36 centres, 17 (5%) at 9 centres had undergone gonadectomy before their first presentation to the specialist centre. Median age at gonadectomy of cases from high-income countries and low-/middle-income countries (LMIC) was 13.0 years (0.1, 68) years and 16.5 years (1, 28), respectively (Pâ< 0.0001) with the likelihood of long-term retention of gonads being higher in LMIC countries.
Conclusions
The likelihood of gonadectomy depends on the underlying diagnosis, sex of rearing and the geographical setting. Clinical benchmarks, which can be studied across all forms of DSD will allow a better understanding of the variation in the practice of gonadectomy
Bing and Neel Syndrome
Introduction. We report the case of a Bing and Neel syndrome revealed by an isolated left ptosis. Case Report. a 57-year-old man was followed up since October 2003 for a typical Waldenströmâs macroglobulinemia. A first complete remission was obtained with chlorambucil. In August 2004, he relapsed. A second complete remission was obtained with RFC chemotherapy regimen (rituximab, fludarabine, and cyclophosphamide). In October 2009, the patient presented with an isolated left ptosis revealing a Bing and Neel syndrome. The diagnosis was suspected on MRI and confirmed by the detection in the CSF of a monoclonal IgM similar to the one found in the plasma. A quite good partial remission has been obtained after one course of RDHAP (rituximab, dexamethasone, cytarabine, and cisplatin) and 3 courses of RDHOx (rituximab, dexamethasone, cytarabine, and oxaliplatin), in addition to ten intrahectal chemotherapy injections. The treatment was followed by intensification and autologous stem cell transplantation. At D58, the patient died due to a septic shock. Conclusion. BNS is a rare and potentially treatable complication of WM. It should be considered in patients with neurologic symptoms and a history of WM
Analytical and experimental study of electrical conductivity in the lithium tantalate nonstoichiometric structure
We have been interested to experimental and analytical studies of ionic conductivity of nonstoichiometric LiTaO 3 solid solutions. Theoretical approach combined with lithium and tantalate vacancy models has been performed. A comparative study between the calculated and measured values is presented taking into account the temperature and composition effects on the conductivity. I