A micropillar array-based microfluidic chip for label-free separation of circulating tumor cells: The best micropillar geometry?

Introduction The information derived from the number and characteristics of circulating tumor cells (CTCs), is crucial to ensure appropriate cancer treatment monitoring. Currently, diverse microfluidic platforms have been developed for isolating CTCs from blood, but it remains a challenge to develop a low-cost, practical, and efficient strategy. Objectives This study aimed to isolate CTCs from the blood of cancer patients via introducing a new and efficient micropillar array-based microfluidic chip (MPA-Chip), as well as providing prognostic information and monitoring the treatment efficacy in cancer patients. Methods We fabricated a microfluidic chip (MPA-Chip) containing arrays of micropillars with different geometries (lozenge, rectangle, circle, and triangle). We conducted numerical simulations to compare velocity and pressure profiles inside the micropillar arrays. Also, we experimentally evaluated the capture efficiency and purity of the geometries using breast and prostate cancer cell lines as well as a blood sample. Moreover, the device’s performance was validated on 12 patients with breast cancer (BC) in different states. Results The lozenge geometry was selected as the most effective and optimized micropillar design for CTCs isolation, providing high capture efficiency (>85 %), purity (>90 %), and viability (97 %). Furthermore, the lozenge MPA-chip was successfully validated by the detection of CTCs from 12 breast cancer (BC) patients, with non-metastatic (median number of 6 CTCs) and metastatic (median number of 25 CTCs) diseases, showing different prognoses. Also, increasing the chemotherapy period resulted in a decrease in the number of captured CTCs from 23 to 7 for the metastatic patient. The MPA-Chip size was only 0.25 cm2 and the throughput of a single chip was 0.5 ml/h, which can be increased by multiple MPA-Chips in parallel. Conclusion The lozenge MPA-Chip presented a novel micropillar geometry for on-chip CTC isolation, detection, and staining, and in the future, the possibilities can be extended to the culture of the CTCs

Year in review in Intensive Care Medicine 2010: III. ARDS and ALI, mechanical ventilation, noninvasive ventilation, weaning, endotracheal intubation, lung ultrasound and paediatrics

SCOPUS: re.jinfo:eu-repo/semantics/publishe

EIC Climate Change Technology Conference 2013 1 CFD Investigation of 2D and 3D Turbulence Structures Effects on a Small Straight-Blade Vertical Axis Wind Turbine CCTC 2013 Paper Number 1569697193

Abstract This paper investigates the accuracy of a CFD model to capture the complex flow around a small vertical axis wind turbine (VAWT) on 2D and 3D grid. Therefore, an Unsteady ReynoldsAveraged Navier-Stokes analysis is performed with parallel OpenFOAM solver based on the Spalart-Allmaras (SA) turbulence model. A grid convergence study is conducted on 2D grids to examine our CFD model sensitivity to grid resolution. Moreover, a 3-D grid of the VAWT is modeled in order to explore the influence of the 3D effects on the aerodynamic performance of the turbine. Keywords: grid convergence, Spalart-Allmaras, tip vortex, Vertical Axis Wind Turbine Résumé Cette étude a pour objet l'évaluation de l'exactitude d'un modèle CFD (dynamique des fluides numérique) conçu pour représenter l'écoulement complexe autour d'une petite éolienne à axe vertical (SVAWT) munie de quatre pales, sur des grilles 2D et 3D. La complexité aérodynamique de l'écoulement est attribuable essentiellement à la variation rapide de l'angle d'attaque de chaque pale. L'écoulement obtenu comporte des zones de décollement important, un décrochage dynamique et une interaction sillage-pale. Une analyse instationnaire est effectuée à l'aide des équations de Navier-Stokes en moyenne de Reynolds (URANS), avec calculs en parallèle au moyen du solveur OpenFOAM® en se basant sur le modèle de turbulence Spalart-Allmaras (SA), et cela en vue de saisir ces phénomènes complexes. La méthode numérique fait appel au schéma implicite d'Euler et au schéma amont pour la discrétisation du temps et de l'espace, respectivement. En outre, une technique d'interface glissante sert à interpoler les valeurs à la limite entre les domaines mobile et stationnaire. Une étude de convergence de grille est réalisée sur la grille 2D afin d'évaluer la sensibilité de notre modèle CFD à la résolution de grille. On utilise en conséquence un résiduel de grille moyenne de y+ >30, ainsi qu'un traitement de paroi afin de représenter les structures de l'écoulement dans les régions voisines de la paroi. En outre, on modélise une grille 3D de l'éolienne à axe vertical (VAWT) dans le but d'examiner l'influence des effets 3D sur les performances aérodynamiques de l'éolienne. L'étude est spécialement axée sur la visualisation de la formation de vortex aux pointes et sur leurs répercussions sur les charges et la puissance de la VAWT. Mots-clés : convergence de grille, Spallat-Allmaras, vortex aux pointes, éolienne à axe vertica

Current–voltage modeling of graphene-based DNA sensor

Graphene is considered as an excellent biosensing material due to its outstanding and unique electronic properties such as providing large area detection, ultra-high mobility and ambipolar field-effect characteristic. In this paper, general conductance model of DNA sensor-based graphene is obtained, and the electrical performance of nanostructured graphene-based DNA sensor is evaluated by the current–voltage characteristic. As a result, by increasing the complementary DNA concentration, the drain current is going toward higher amounts