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961.
962.
Luca Bilancetti Denis Poncelet Catherine Loisel Stefania Mazzitelli Claudio Nastruzzi 《AAPS PharmSciTech》2010,11(3):1257-1267
This article describes the preparation of starch particles, by spray drying, for possible application to a dry powder coating
process. Dry powder coating consists of spraying a fine powder and a plasticizer on particles. The efficiency of the coating
is linked to the powder morphological and dimensional characteristics. Different experimental parameters of the spray-drying
process were analyzed, including type of solvent, starch concentration, rate of polymer feeding, pressure of the atomizing
air, drying air flow, and temperature of drying air. An optimization and screening of the experimental parameters by a design
of the experiment (DOE) approach have been done. Finally, the produced spray-dried starch particles were conveniently tested
in a dry coating process, in comparison to the commercial initial starch. The obtained results, in terms of coating efficiency,
demonstrated that the spray-dried particles led to a sharp increase of coating efficiency value. 相似文献
963.
Aude Rauscent Didier Le Ray Marie-Jeanne Cabirol-Pol Keith T. Sillar John Simmers Denis Combes 《Journal of Physiology》2006,100(5-6):317-327
Metamorphosis in the anuran frog, Xenopus laevis, involves profound structural and functional transformations in most of the organism's physiological systems as it encounters a complete alteration in body plan, habitat, mode of respiration and diet. The metamorphic process also involves a transition in locomotory strategy from axial-based undulatory swimming using alternating contractions of left and right trunk muscles, to bilaterally-synchronous kicking of the newly developed hindlimbs in the young adult. At critical stages during this behavioural switch, functional larval and adult locomotor systems co-exist in the same animal, implying a progressive and dynamic reconfiguration of underlying spinal circuitry and neuronal properties as limbs are added and the tail regresses. To elucidate the neurobiological basis of this developmental process, we use electrophysiological, pharmacological and neuroanatomical approaches to study isolated in vitro brain stem/spinal cord preparations at different metamorphic stages. Our data show that the emergence of secondary limb motor circuitry, as it supersedes the primary larval network, spans a developmental period when limb circuitry is present but not functional, functional but co-opted into the axial network, functionally separable from the axial network, and ultimately alone after axial circuitry disappears with tail resorption. Furthermore, recent experiments on spontaneously active in vitro preparations from intermediate metamorphic stage animals have revealed that the biogenic amines serotonin (5-HT) and noradrenaline (NA) exert short-term adaptive control over circuit activity and inter-network coordination: whereas bath-applied 5-HT couples axial and appendicular rhythms into a single unified pattern, NA has an opposite decoupling effect. Moreover, the progressive and region-specific appearance of spinal cord neurons that contain another neuromodulator, nitric oxide (NO), suggests it plays a role in the maturation of limb locomotor circuitry. In summary, during Xenopus metamorphosis the network responsible for limb movements is progressively segregated from an axial precursor, and supra- and intra-spinal modulatory inputs are likely to play crucial roles in both its functional flexibility and maturation. 相似文献
964.
Tran Hoan Q. Tran Van T. H. Nguyen Chinh T. Nguyen Oanh T. K. Do Thinh T. Le Hung N. Tikhonenkov Denis V. 《Limnology》2022,23(2):327-335
Limnology - Data on the distribution and species-environment relationships of rare and endemic species of protists in Asian tropical waterbodies could provide valuable information for better... 相似文献
965.
966.
Rolf Zeller Denis Duboule 《BioEssays : news and reviews in molecular, cellular and developmental biology》1997,19(7):541-546
Molecular and developmental studies of limb pattern formation have recently gained widespread attention. The fact that vertebrate limbs are amenable to both genetic and embryological manipulations has established this model system as a valuable paradigm for studying vertebrate development. Limb buds are polarised along all three major axes and the establishment of the dorso-ventral (DV) polarity is dependent upon cues localised in the trunk, where a DV ectodermal interface is produced by confrontation of dorsal and ventral identities. By analogy to Drosophila imaginal disc development, this interface has been proposed to determine and position an ectodermal organising centre, the Apical Ectodermal Ridge (AER), controlling limb bud outgrowth. Recent fate mapping studies(1) and studies of genes regulating DV limb polarity(2-6), AER formation(7,8) and differentiation(9) suggest, however, that DV patterning and AER induction, though coordinately regulated during limb bud outgrowth, may early on be more dissociated than expected. 相似文献
967.
968.
969.
Jianzhong Yang Shaozhao Wang Marie-Josée Lorrain Denis Rho Kofi Abokitse Peter C. K. Lau 《Applied microbiology and biotechnology》2009,84(5):867-876
Recombinant Escherichia coli whole-cell biocatalysts harboring either a Baeyer–Villiger monooxygenase or ferulic acid decarboxylase were employed in organic-aqueous
two-phase bioreactor systems. The feasibility of the bioproduction of water-insoluble products, viz., lauryl lactone from
cyclododecanone and 4-vinyl guaiacol from ferulic acid were examined. Using hexadecane as the organic phase, 10∼16 g of lauryl
lactone were produced in a 3-l bioreactor that operated in a semicontinuous mode compared to 2.4 g of product in a batch mode.
For the decarboxylation of ferulic acid, a new recombinant biocatalyst, ferulic acid decarboxylase derived from Bacillus pumilus, was constructed. Selected solvents as well as other parameters for in situ recovery of vinyl guaiacol were investigated.
Up to 13.8 g vinyl guaiacol (purity of 98.4%) were obtained from 25 g of ferulic acid in a 2-l working volume bioreactor by
using octane as organic phase. These selected examples highlight the superiority of the two-phase biotransformations systems
over the conventional batch mode. 相似文献
970.