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  • 1
    Electronic Resource
    Electronic Resource
    A new method of three-dimensional computer assisted reconstruction of the developing biliary tract (1999)
    Springer
    Surgical and radiologic anatomy 21 (1999), S. 55-58 
    Details
    ISSN: 1279-8517
    Keywords: Three-dimensional computer assisted reconstruction ; Biliary tract ; Human embryo ; Carnegie stage 23
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Une reconstruction tridimensionnelle assistée par ordinateur de l'arbre biliaire a été réalisée chez des embryons de rats et un embryon humain pour décrire et comparer les structures biliaires et pour mettre en évidence les rapports anatomiques des différents éléments du pédicule hépatique. Des coupes sagittales (épaisseur de 7 µm) d'un embryon humain et de 16 embryons de rat ont été directement acquises par ordinateur. Les coupes sériées ont été automatiquement alignées. Les données ont été analysées en utilisant une segmentation et un seuillage permettant une reconstruction automatique. Les voies biliaires principales avaient un trajet ascendant dans le mésoderme du ligament hépato-duodénal. Les voies biliaires extra-hépatiques : conduit cholédoque (CD), conduit cystique et la vésicule biliaire chez l'humain, étaient en continuité. L'ampoule hépato-pancréatique a été explorée par transparence à travers le duodénum. Le CD avait un trajet en chicane. Le diamètre et la longueur de la vésicule biliaire étaient identiques à celles du CD. La reconstruction assistée par ordinateur permet une acquisition aisée des données par l'examen direct des coupes histologiques à travers un microscope. Cette méthode détermine clairement les relations entre les différents éléments du pédicule hépatique et leur volume, ce qui n'était pas évident à l'examen en 2 dimensions des coupes histologiques. Chaque stade embryonnaire pourrait être ainsi reconstruit en 3-D, introduisant ainsi le temps comme quatrième dimension, ceci étant fondamental pour l'étude de l'organogénèse.
    Notes: Summary A three-dimensional (3-D) computer assisted reconstruction of the biliary tract was performed in human and rat embryos at Carnegie stage 23 to describe and compare the biliary structures and to point out the anatomic relations between the structures of the hepatic pedicle. Light micrograph images from consecutive serial sagittal sections (diameter 7 mm) of one human and 16 rat embryos were directly digitalized with a CCD camera. The serial views were aligned automatically by software. The data were analysed following segmentation and thresholding, allowing automatic reconstruction. The main bile ducts ascended in the mesoderm of the hepatoduodenal ligament. The extrahepatic bile ducts: common bile duct (CD), cystic duct and gallbladder in the human, formed a compound system which could not be shown so clearly in histologic sections. The hepato-pancreatic ampulla was studied as visualised through the duodenum. The course of the CD was like a chicane. The gallbladder diameter and length were similar to those of the CD. Computer-assisted reconstruction permitted easy acquisition of the data by direct examination of the sections through the microscope. This method showed the relationships between the different structures of the hepatic pedicle and allowed estimation of the volume of the bile duct. These findings were not obvious in two-dimensional (2-D) views from histologic sections. Each embryonic stage could be rebuilt in 3-D, which could introduce the time as a fourth dimension, fundamental for the study of organogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01635054
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  • 2
    Electronic Resource
    Electronic Resource
    Carpal bone maturation during childhood and adolescence: Assessment by quantitative computed tomography (1998)
    Springer
    Surgical and radiologic anatomy 19 (1998), S. 395-398 
    Details
    ISSN: 1279-8517
    Keywords: Bone maturation ; Carpal bone ; Volume ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of our study was to measure the volume of each carpal bone during childhood and adolescence by image processing from computed tomography (CT) scans, and to analyze the relationship between the eight carpal bones. Thirteen CT scans were performed in nine normal prepubertal, peripubertal and post-pubertal children, six boys and three girls, aged 5-14 years. Each scan was processed in order to extract the carpal bones. The volume was computed for each bone. There was a significant correlation between carpal bone volume and age (0.55 〈 r 〈 0.79), and a very strong correlation between the volume of a given carpal bone and the volume of all the others, whatever the age (0.87 〈 r 〈 0.99, p 〈 0.01). Image processing is a potentially useful method for assessing bone maturation. The constant ratio between carpal bone volumes indicates that these bones interact with each other in wrist bone maturation
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00276-997-0395-x
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  • 3
    Electronic Resource
    Electronic Resource
    A new method of three-dimensional computer assisted reconstruction of the developing biliary tract (1999)
    Springer
    Surgical and radiologic anatomy 21 (1999), S. 55-58 
    Details
    ISSN: 1279-8517
    Keywords: Three-dimensional computer assisted reconstruction ; Biliary tract ; Human embryo ; Carnegie stage 23
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A three-dimensional (3-D) computer assisted reconstruction of the biliary tract was performed in human and rat embryos at Carnegie stage 23 to describe and compare the biliary structures and to point out the anatomic relations between the structures of the hepatic pedicle. Light micrograph images from consecutive serial sagittal sections (diameter 7 mm) of one human and 16 rat embryos were directly digitalized with a CCD camera. The serial views were aligned automatically by software. The data were analysed following segmentation and thresholding, allowing automatic reconstruction. The main bile ducts ascended in the mesoderm of the hepatoduodenal ligament. The extrahepatic bile ducts: common bile duct (CD), cystic duct and gallbladder in the human, formed a compound system which could not be shown so clearly in histologic sections. The hepato-pancreatic ampulla was studied as visualised through the duodenum. The course of the CD was like a chicane. The gallbladder diameter and length were similar to those of the CD. Computer-assisted reconstruction permitted easy acquisition of the data by direct examination of the sections through the microscope. This method showed the relationships between the different structures of the hepatic pedicle and allowed estimation of the volume of the bile duct. These findings were not obvious in two-dimensional (2-D) views from histologic sections. Each embryonic stage could be rebuilt in 3-D, which could introduce the time as a fourth dimension, fundamental for the study of organogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00276-999-0055-4
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  • 4
    Electronic Resource
    Electronic Resource
    Carpal bone maturation during childhood and adolescence: Assessment by quantitative computed tomography (1997)
    Springer
    Surgical and radiologic anatomy 19 (1997), S. 395-398 
    Details
    ISSN: 1279-8517
    Keywords: Bone maturation ; Carpal bone ; Volume ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Le but de notre étude était de mesurer le volume de chaque os du carpe au cours de l'enfance et de l'adolescence par analyse des images d'examens tomodensitométriques (TDM) du poignet, et d'analyser les relations entre les huit os du carpe. Treize TDM ont été réalisés chez 9 enfants en période prépubertaire, pubertaire et postpubertaire, 6 garçons et 3 filles, âgés de 5 à 14 ans. Les os du carpe ont été isolés les uns des autres sur chaque examen TDM et leurs volumes ont été calculés. Nous avons retrouvé une relation significative entre le volume des os du carpe et l'âge (0,55〈r〈0,79), et une relation très significative entre le volume d'un os du carpe et le volume des autres os du carpe, quel que soit l'âge (0,87〈r〈0,99, p〈0,01). L'analyse d'image est une méthode intéressante pour évaluer la maturation osseuse. Le rapport constant entre le volume des os du carpe, quel que soit l'âge, semble indiquer que les os du carpe interagissent entre eux durant la maturation osseuse du poignet.
    Notes: Summary The aim of our study was to measure the volume of each carpal bone during childhood and adolescence by image processing from computed tomography (CT) scans, and to analyze the relationship between the eight carpal bones. Thirteen CT scans were performed in nine normal prepubertal, peripubertal and post-pubertal children, six boys and three girls, aged 5–14 years. Each scan was processed in order to extract the carpal bones. The volume was computed for each bone. There was a significant correlation between carpal bone volume and age (0.55〈r〈0.79), and a very strong correlation between the volume of a given carpal bone and the volume of all the others, whatever the age (0.87〈r〈0.99, p〈0.01). Image processing is a potentially useful method for assessing bone maturation. The constant ratio between carpal bone volumes indicates that these bones interact with each other in wrist bone maturation
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01628507
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  • 5
    Electronic Resource
    Electronic Resource
    Transcranial magnetic stimulation: specific and non-specific facilitation of magnetic motor evoked potentials (1990)
    Springer
    Journal of neurology 237 (1990), S. 416-419 
    Details
    ISSN: 1432-1459
    Keywords: Transcranial magnetic stimulation ; Motor evoked potentials ; Cortico-spinal system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Different physiological mechanisms of facilitation of latencies and amplitudes of magnetic motor evoked potentials (MEPs) were evaluated in a cohort of 140 healthy volunteers. The potentials were induced at the vertex and recorded at the abductor pollicis brevis. The aim of the present investigation was to compare physiological mechanisms which presumably facilitate motor pathways at the cortical level with those known to occur during contraction of small hand muscles. When compared with MEPs at rest, the maximum average decrease of latencies (1.5, SD 1.1 ms) as well as the highest increase of peak to peak amplitudes (2.6, SD 2.1 mV) was observed during exertion of a voluntary background force, at the muscle recorded from. Pre-innervation of a neighbouring muscle (abductor digiti minimi) led to a lesser average decrease of latencies by 1.0, SD 1.1 ms and an average increase of amplitudes by only 0.5, SD 1.5 mV. Non-specific manoeuvres, like sticking out the tongue or counting aloud, reduced mean latencies slightly by 0.4 ms, SD 0.8 ms and 0.3 SD 0.85 ms respectively, but increased amplitudes markedly by an average of 1.0, SD 1.6 mV and 0.8, SD 1.4mV respectively. It is concluded that facilitation of MEPs by non-specific manoeuvres occurs and must be taken into account when evaluating MEPs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314732
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  • 6
    Electronic Resource
    Electronic Resource
    Modulation of tight junction morphology and permeability by an epithelial factor (1994)
    Springer
    The journal of membrane biology 139 (1994), S. 41-48 
    Details
    ISSN: 1432-1424
    Keywords: Tight junction ; Intercellular junctions ; Transepithelial permeability ; Transepithelial electrical resistance (TER) ; MDCK, A6, Caco-2 epithelial cell cultures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We report evidence of a factor secreted at the apical side of epithelial monolayers which modulates tight junction structure and permeability. This activity was detected within 4–7 days of conditioning of the apical medium by MDCK, A6 or Caco-2 epithelial cell lines cultured on permeable membranes in bipartite chambers. Apical conditioned medium (ACM), applied to the basolateral surface of a confluent monolayer, increased the transepithelial electrical resistance (TER), progressively reaching values 12–22% higher than the baseline within 5–10 min. After 40–60 min, the TER returned slowly to the basal value. This phenomenon was not observed either when using preheated ACM or the ACM filtrate obtained through a 30,000 MW cutoff membrane. The ACM maintained its activity even when applied to cell lines from different organs and species, as demonstrated when ACM from MDCK monolayers promoted an increase of 22% in the TER of Caco-2 cells. The increase of TER induced by the ACM treatment is accompanied by a change in the distribution of the number of tight junction strands, from an initial pattern, dominated mostly by junctions with one or two strands, to a new pattern after treatment dominated by junctions with two or three strands. Our results suggest the existence of a mechanism in epithelial cells that could signal leakage of apically secreted components to the basolateral side, thereby modulating the junction structure and permeability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232673
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  • 7
    Electronic Resource
    Electronic Resource
    The human auditory pathways - A quantitative study
    Amsterdam : Elsevier
    Brain and Language 4 (1977), S. 152-155 
    Details
    ISSN: 0093-934X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Linguistics and Literary Studies , Medicine , Psychology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0093-934X(77)90013-X
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  • 8
    Electronic Resource
    Electronic Resource
    Antiresonant reflecting optical waveguides in strip configuration (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 276-278 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A monomode antiresonant reflecting optical strip waveguide has been realized in SiON. The lateral confinement is provided by strip-loaded reflectors fabricated by reactive ion beam etching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.111179
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  • 9
    Electronic Resource
    Electronic Resource
    Diffusional separation of gases by sinusoidal oscillations (1987)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 30 (1987), S. 1023-1025 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It is shown that gas mixtures can be separated at relatively high differential flow rates by an enhanced diffusion technique involving the oscillation of gases within a capillary bundle in the presence of axial concentration gradients. Experimental data for the diffusional separation of both He–CO2 and CO2–SF6 mixtures into an O2 carrier are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866300
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  • 10
    Electronic Resource
    Electronic Resource
    Numerical investigation of thermocapillary flow around a bubble (1999)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 11 (1999), S. 18-29 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermocapillary flow induced by a gas bubble in a Newtonian liquid layer subjected to a stable temperature stratification is investigated. This flow is analyzed for a special configuration when the surface tension and buoyant forces oppose one another. The driving mechanism is the surface tension gradient related to the Marangoni number whereas the stabilizing effects are the viscous and buoyant forces related to the Prandtl and the Rayleigh numbers. In a previous work, this flow has been investigated experimentally for a few combinations of these three parameters. In order to make a more systematic study of the influence of these parameters, numerical simulations are used as a decisive tool. Indeed, it allows the contribution of the different mechanisms to be evaluated. To validate the finite element model, developed for this purpose, the numerical results are first compared to experimental ones. Then, the influence of these three dimensionless parameters on the flow pattern and the magnitude of the flow is analyzed. This sensitivity study is supplemented by a convergence study. It appears that the Rayleigh number modifies the flow pattern but has little influence on the strength of the primary vortex induced by the bubble. On the other hand, the Marangoni and Prandtl numbers induce little change in the flow pattern but they respectively enhance and reduce the strength of the primary vortex. This systematic analysis leads us to propose an empirical relationship for the strength of the flow. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.869900
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