Inner ear ossification and mineralization kinetics in human embryonic development - microtomographic and histomorphological study.

Little is known about middle and inner ear development during the second and third parts of human fetal life. Using ultra-high resolution Microcomputed Tomography coupled with bone histology, we performed the first quantitative middle and inner ear ossification/mineralization evaluation of fetuses between 17 and 39 weeks of gestational age. We show distinct ossification paces between ossicles, with a belated development of the stapes. A complete cochlear bony covering is observed within the time-frame of the onset of hearing, whereas distinct time courses of ossification for semicircular canal envelopes are observed in relation to the start of vestibular functions. The study evidences a spatio-temporal relationship between middle and inner ear structure development and the onset of hearing and balance, critical senses for the fetal adaptation to birth

Time resolved particle dynamics in granular convection

We present an experimental study of the movement of individual particles in a layer of vertically shaken granular material. High-speed imaging allows us to investigate the motion of beads within one vibration period. This motion consists mainly of vertical jumps, and a global ordered drift. The analysis of the system movement as a whole reveals that the observed bifurcation in the flight time is not adequately described by the Inelastic Bouncing Ball Model. Near the bifurcation point, friction plays and important role, and the branches of the bifurcation do not diverge as the control parameter is increased. We quantify the friction of the beads against the walls, showing that this interaction is the underlying mechanism responsible for the dynamics of the flow observed near the lateral wall

Contributory Factors to Unsteadiness During Walking Up and Down Stairs in Patients With Diabetic Peripheral Neuropathy

OBJECTIVE Although patients with diabetic peripheral neuropathy (DPN) are more likely to fall than age-matched controls, the underlying causative factors are not yet fully understood. This study examines the effects of diabetes and neuropathy on strength generation and muscle activation patterns during walking up and down stairs, with implications for fall risk. RESEARCH DESIGN AND METHODS Sixty-three participants (21 patients with DPN, 21 diabetic controls, and 21 healthy controls) were examined while walking up and down a custom-built staircase. The speed of strength generation at the ankle and knee and muscle activation patterns of the ankle and knee extensor muscles were analyzed. RESULTS Patients with neuropathy displayed significantly slower ankle and knee strength generation than healthy controls during stair ascent and descent (P < 0.05). During ascent, the ankle and knee extensor muscles were activated significantly later by patients with neuropathy and took longer to reach peak activation (P < 0.05). During descent, neuropathic patients activated the ankle extensors significantly earlier, and the ankle and knee extensors took significantly longer to reach peak activation (P < 0.05). CONCLUSIONS Patients with DPN are slower at generating strength at the ankle and knee than control participants during walking up and down stairs. These changes, which are likely caused by altered activations of the extensor muscles, increase the likelihood of instability and may be important contributory factors for the increased risk of falling. Resistance exercise training may be a potential clinical intervention for improving these aspects and thereby potentially reducing fall risk

ANALYSIS/SYNTHESIS OF QUASI-HARMONIC SOUNDS BY USE OF THE KARPLUS-STRONG ALGORITHM

In the Karplus-Strong method, the synthetic sound is obtained by exciting a recursive comb-filter with a burst of noise. An analysis scheme is presented in this paper, which makes it possible to derive the optimal Karplus-Strong synthesis parameters from the recording of a real instrument. In addition, an excitation signal can be calculated and used in place of the usual burst of white or colored noise, in order to obtain more realistic syntheses

Appareillage d'épitaxie de composés semiconducteurs par transport réactif à courte distance

We describe an apparatus which is used for the transport of a material upon a substrate, in a vessel where the pressure or the flow rate of the reactive gas are determined ; the mean characteristics are the control and the stability of the temperature, the fast settlement of the thermal program and the possibility of in situ operations. Measurement accuracy and use flexibility make this apparatus well adapted to experimental research. The epitaxial growth of a compound semiconductor (CdTe) is given as an example of application.L'appareillage décrit est un système permettant de réaliser le transport d'un matériau sur un substrat, dans une enceinte où la pression - ou le débit - du gaz réactif peuvent être fixés ; les caractéristiques principales résident dans le contrôle et la stabilisation des températures, la rapidité d'établissement des programmes thermiques et la multiplicité des interventions in situ. Précision des mesures et souplesse d'utilisation sont les qualités qui font de cet appareillage un bon outil de recherche expérimentale. Un exemple d'application à la croissance épitaxique d'un composé semiconducteur (CdTe) est présenté

Role of the glyoxalase system in astrocyte-mediated neuroprotection.

The glyoxalase system is the most important pathway for the detoxification of methylglyoxal (MG), a highly reactive dicarbonyl compound mainly formed as a by-product of glycolysis. MG is a major precursor of advanced glycation end products (AGEs), which are associated with several neurodegenerative disorders. Although the neurotoxic effects of MG and AGEs are well characterized, little is known about the glyoxalase system in the brain, in particular with regards to its activity in different neural cell types. Results of the present study reveal that both enzymes composing the glyoxalase system [glyoxalase-1 (Glo-1) and Glo-2] were highly expressed in primary mouse astrocytes compared with neurons, which translated into higher enzymatic activity rates in astrocytes (9.9- and 2.5-fold, respectively). The presence of a highly efficient glyoxalase system in astrocytes was associated with lower accumulation of AGEs compared with neurons (as assessed by Western blotting), a sixfold greater resistance to MG toxicity, and the capacity to protect neurons against MG in a coculture system. In addition, Glo-1 downregulation using RNA interference strategies resulted in a loss of viability in neurons, but not in astrocytes. Finally, stimulation of neuronal glycolysis via lentiviral-mediated overexpression of 6-phosphofructose-2-kinase/fructose-2,6-bisphosphatase-3 resulted in increased MG levels and MG-modified proteins. Since MG is largely produced through glycolysis, this suggests that the poor capacity of neurons to upregulate their glycolytic flux as compared with astrocytes may be related to weaker defense mechanisms against MG toxicity. Accordingly, the neuroenergetic specialization taking place between these two cell types may serve as a protective mechanism against MG-induced neurotoxicity

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National audienc

L'implication des éleveurs de bovins-viande dans les filières de qualité correspond-elle à des conduites d'élevage spécifiques ?

National audienceWe investigated the management and marketing practices for females and products in 21 Charolais farms specializing in beef production. Oar aim was to verify the assumption that some farmers adjust their system so as to maximize the number of animals sold in the quality meat sector as against other farmers having different priorities (e.g. simplifying their management). Based on enquiries in four producer groups, we formed two samples of out of these two farmer categories. Three main results were derived from the study. 1) For the producer groups, the chief discriminating factor between the two samples is the number and proportion of animals transiting through their groups, and not the total number of animals sold by the farmers in the quality meat sector. 2) The number of animals sold in the quality meat sector does not adequately reflect the capacity of farmers to produce animals meeting the technical specifications of the sector, as a great part of the animals are marketed through other channels, in particular directly via independent butchers. 3) The farmers most implicated in the quality meat sector do not necessarily adopt specific management practices, in particular more meticulous, more individual-focused management than others. But these farmers delegate far more extensively the marketing function to the producer groups, even though this may involve lower valorisation of each individual animal. Based on these results we propose and discuss a new classification of farmers combining their practices and their implication in the quality meat sector. With 5 distinct groups of farmers, this classification is more complex than the one drawn up in oar initial assumption.Les pratiques de conduite du troupeau (femelles et produits) et de commercialisation des animaux ont été étudiées dans 21 élevages. Charolais spécialisés en production de viande bovine. Il s'agissait de tester l'hypothèse selon laquelle certains éleveurs orientent leur système de production dans l'objectif de maximiser le nombre d'animaux vendus dans les filières qualité, par rapport à d'autres pour lesquels les priorités sont différentes (simplification de la conduite). Deux échantillons d'éleveurs ont été constitués selon ces deux catégories à partir d'enquêtes auprès de 4 groupements de producteurs. Trois types de résultats ressortent de l'étude : 1) les groupements ont discriminé les deux échantillons d'abord en fonction des effectifs et de la proportion d'animaux transitant effectivement par eux, et non en fonction du nombre d'animaux vendus dans les filières qualité, 2) le nombre d'animaux vendus dans les filières qualité ne suffit pas à rendre compte de la capacité des éleveurs à produire des animaux conformes aux cahiers des charges de ces filières, une grande partie de ceux-ci pouvant être valorisés autrement (notamment via des bouchers), 3) les éleveurs les plus impliqués dans les filières qualité n'ont pas forcément adopté des pratiques spécifiques, notamment une gestion plus minutieuse, plus "à l'individu" que les autres. Par contre, ils délèguent beaucoup plus la fonction de commercialisation à la structure d'aval, quitte à une moindre valorisation de chaque animal pris individuellement. Une autre classification des éleveurs combinant à la fois les pratiques et l'implication dans les filières qualité est alors proposée et discutée, plus complexe que celle correspondant à l'hypothèse de départ (5 groupes distincts)