196 research outputs found

    Understanding antral contraction in human stomach through comparison with soft elastic reactor

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    IntroductionHuman digestion, a major concern due to the rapid development of nutrition-related chronic diseases,rely apart from enzymatic reactions on homogenization of the gastric content by antral contractions.Although recent CFD studies made it possible to explore the influence of the rheologicalproperties of the gastric content on the efficiency of gastric mixing, this key step is yet far from beingfully understood.ObjectiveThis work aims at discussing the influences of contraction frequency and viscosity of the digestain human gastric mixing by comparison with the mixing efficiency of an innovative soft elastic reactor(SER), that induces mixing by vibration of its wall in a similar way as antral contraction waves(ACWs) promote stomach motility.MethodologyIn this view, the SER mixing curve, recently established by Delaplace et al. (2018) using a dimensionalanalysis approach, was considered in order to determine the flow regime under which thegastric mixing of foods (viscosity ranging from 10-3 to 1 Pa.s) was performedMain findingsIt was shown that depending on the viscosity of the SER/stomach content and the amplitude of penetration/ACWs, the number of strikes/contractions required to achieve homogenization was largelydifferent. Moreover, the operating points of SER and ACWs mixing were close, justifying the comparisonbetween both reactors.ConclusionBased on this, the level of mechanical solicitation provided by human peristalsis was shown to benot as high as expected, and the mixing performance of distal region, confined in laminar regime,was found limited and not only due to mechanical solicitations. Further efforts are needed to investigatethe role of other physiological processes such as gastric secretions and gastric emptying inmixing performance of intragastric fluid homogenized by the antral contraction

    Modélisation d'horizons sismiques à l'aide des algorithmes génétiques

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    Dans le contexte de l'analyse des images sismiques, ce travail propose la mise en valeur de structures continues (horizons) par une nouvelle méthode de reconnaissance de formes nommée « approche par correspondance géométrique ». Il s'agit d'une mesure non linéaire de similitude entre vecteurs qui correspondent respectivement, dans notre cas, à un segment particulier et préalablement choisi (horizon de référence) et un segment quelconque de l'image traitée. Le segment dit de référence est représenté par un modÚle polynomial estimé à l'aide des algorithmes génétiques. Nous avons ainsi obtenu une carte d'attribut de similitude qui renforce la géométrie de structures géologiques initialement peu visibles sur une image sismique réelle

    Quantification de l'architecture osseuse par microtomographie 3D utilisant le rayonnement synchrotron

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    Nous prĂ©sentons un systĂšme de microtomographie 3D par rayonnement synchrotron dĂ©veloppĂ© Ă  l'ESRF de Grenoble, en vue de l'analyse de la structure trabĂ©culaire osseuse. Ce systĂšme permet d'acquĂ©rir de façon non destructive des images 3D d'Ă©chantillons osseux , ayant des voxels isotrope de 6.65 ÎŒm. Afin de caractĂ©riser la structure 3D de l'os, des paramĂštres quantitatifs sont extraits de ces images. Les paramĂštres morphologiques et topologiques utilisĂ©s en histomorphomĂ©trie, sont calculĂ©s sur les diffĂ©rentes coupes du volume. La variabilitĂ© des paramĂštres dans l'Ă©chantillon et la nĂ©cessitĂ© d'une analyse rĂ©ellement tridimensionnelle sont soulignĂ©s. L'influence de la rĂ©solution spatiale sur l'exactitude des paramĂštres calculĂ©s est Ă©galement examinĂ©e

    A low-cost HPV immunochromatographic assay to detect high-grade cervical intraepithelial neoplasia

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    Objective To evaluate the reproducibility and accuracy of the HPV16/18-E6 test. Methods The study population was comprised of 448 women with a previously abnormal Pap who were referred to the Barretos Cancer Hospital (Brazil) for diagnosis and treatment. Two cervical samples were collected immediately before colposcopy, one for the hr-HPV-DNA test and cytology and the other for the HPV16/18-E6 test using high-affinity monoclonal antibodies (mAb). Women with a histologic diagnosis of cervical intraepithelial neoplasia grade 2 or 3 were considered to be positive cases. Different strategies using a combination of screening methods (HPV-DNA) and triage tests (cytology and HPV16/18-E6) were also examined and compared. Results The HPV16/18-E6 test exhibited a lower positivity rate compared with the HPV-DNA test (19.0% vs. 29.3%, p<0.001) and a moderate/high agreement (kappa = 0.68, 95% CI: 0.60-0.75). It also exhibited a significantly lower sensitivity for CIN2+ and CIN3+ detection compared to the HPV-DNA test and a significantly higher specificity. The HPV16/18-E6 test was no different from cytology in terms of sensitivity, but it exhibited a significantly higher specificity in comparison to ASCH+. A triage test after HPV-DNA detection using the HPV16/18-E6 test exhibited a significantly higher specificity compared with a triage test of ASCH+ to CIN2+ (91.8% vs. 87.4%, p = 0.04) and CIN3+ (88.6% vs. 84.0%, p = 0.05). Conclusion The HPV16/18-E6 test exhibited moderate/high agreement with the HPV-DNA test but lower sensitivity and higher specificity for the detection of CIN2+ and CIN3+. In addition, its performance was quite similar to cytology, but because of the structural design addressed for the detection of HPV16/18-E6 protein, the test can miss some CIN2/3+ lesions caused by other high-risk HPV types.Cancer Prevention Department, Center for the Researcher Support and Pathology Department of the Barretos Cancer Hospital. This study was supported by CNPq 573799/2008-3 and FAPESP 2008/57889-1info:eu-repo/semantics/publishedVersio

    The ThomX project status

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    Work supported by the French Agence Nationale de la recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI - http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/wepro052.pdfA collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay - France. After a period of study and definition of the machine performance, a full description of all the systems has been provided. The infrastructure work has been started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different technical and experimental activities on optical resonators, RF power supplies and on the electron gun

    Drying colloidal systems: laboratory models for a wide range of applications

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    The drying of complex fluids provides a powerful insight into phenomena that take place on time and length scales not normally accessible. An important feature of complex fluids, colloidal dispersions and polymer solutions is their high sensitivity to weak external actions. Thus, the drying of complex fluids involves a large number of physical and chemical processes. The scope of this review is the capacity to tune such systems to reproduce and explore specific properties in a physics laboratory. A wide variety of systems are presented, ranging from functional coatings, food science, cosmetology, medical diagnostics and forensics to geophysics and art
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