Inkjet Metrology: High-Accuracy Mass Measurements of Microdroplets Produced by a Drop-on-Demand Dispenser

We describe gravimetric methods for measuring the mass of droplets generated by a drop-on-demand (DOD) microdispenser. Droplets are deposited, either continuously at a known frequency or as a burst of known number, into a cylinder positioned on a submicrogram balance. Mass measurements are acquired precisely by computer, and results are corrected for evaporation. Capabilities are demonstrated using isobutyl alcohol droplets. For ejection rates greater than 100 Hz, the repeatability of droplet mass measurements was 0.2%, while the combined relative standard uncertainty (uc) was 0.9%. When bursts of droplets were dispensed, the limit of quantitation was 72 μg (1490 droplets) with uc = 1.0%. Individual droplet size in a burst was evaluated by high-speed videography. Diameters were consistent from the tenth droplet onward, and the mass of an individual droplet was best estimated by the average droplet mass with a combined uncertainty of about 1%. Diameters of the first several droplets were anomalous, but their contribution was accounted for when dispensing bursts. Above the limits of quantitation, the gravimetric methods provided statistically equivalent results and permit detailed study of operational factors that influence droplet mass during dispensing, including the development of reliable microassays and standard materials using DOD technologies

Évaluation intégrée de la qualité d’un milieu récepteur basée sur des données en continue validées et la modélisation de la qualité

Colloque avec actes et comité de lecture. Internationale.International audienc

Superhydrophobic functionalization of cutinase activated poly(lactic acid) surfaces

Superhydrophobic materials have focused the interest of many researchers due to their potential in a wide spectrum of applications like microfluidics or biosensors in the biomedical field. Typically, the increased surface roughness at the micro or nano scale needed for superhydrophobic surfaces is achieved by coating of different substances, which in combination with a lower surface energy lead to Water Contact Angle (WCA) values greater than 150\uc2\ub0. Here, limited enzymatic surface hydrolyis poly(lactic acid) (PLA) was combined with spin coating of a steraic alkene ketene dimer (AKD) layer. The selective enzymatic hydrolysis creates, in a gentle and controlled way, new hydroxylic and carboxylic groups on the polymer surface without damaging the material bulk properties like alkaline treatment does. The creation of new hydrophilic surface groups lead to a significant increase in the hydrophilicity, decreasing the WCA to less than 30\uc2\ub0 while raising the roughness from an Rrmsof 50.5 to 90.8 nm concomittantly increasing the exposed surface vs. the projected one by 13.2%. Coupling of PLA hydroxy groups with AKD was demonstrated by using a PLA model substrate and subsequent identification of the reaction product via LC-TOF/MS. On the PLA film, FTIR based detection of the characteristic \uce\ub2-ketoester bond peak between the AKD and enzymatically generated hydroxy groups on the surface confirmed successful coupling. Scanning Electron Microscopy (SEM) & Atomic Force Microscopy (AFM) imaging confirmed the presence of fractal structures after curation of the enzymatically activated PLA film. The suitable size, 4.15 \uce\ubcm on the lateral dimension and 0.7 \uce\ubcm on height of the structures, together with the high density of these fractal structures lead to a superhydrophobic surface (WCA >150\uc2\ub0). This process represents an alternative to produce chemically inert superhydrophobic bio-based polyesters surfaces, by combining mild biocatalytic activation of a polyester film with non-toxic chemicals in an environmentally friendly manner

Organic light-emitting devices fabricated from semiconducting nanospheres

The successful fabrication of organic light emitting diodes (OLEDs) utilizing organic semiconducting polymer nanospheres was reported. The devices consist of a homogeneous single layer of nanosized semiconducting conjugated polymer nanospheres (SPNs) and reveal improved opto-electronic characteristics compared with "traditionally" fabricated OLEDs for which the active layer was cast from a solution of the conjugated polymer in an organic solvent. Optical spectroscopy have evidenced that conjugated polymers can be converted into aqueous SPN dispersions without generation of electronic defects; the SPNs display the photophysical properties of the bulk polymer

Modélisation numérique du comportement d'une particule sous champ électrique dans les microsystèmes (de la déformation au déplacement)

Un nouvel outil numérique pour prédire le mouvement et la déformation de particules sous champ électrique dans les microsystèmes biologiques est proposé. Ce moyen permettra à terme l'optimisation de labopuces dans les premières phases de conception. Le phénomène utilisé pour manipuler les particules est la diélectrophorèse associée au mouvement dû à la polarisation des diélectriques sous champ électrique non uniforme. L'outil numérique utilisé pour le suivi des interfaces mobiles sous champ électrique est la Méthode Intégrale aux Frontières (MIF). Les écoulements sont supposés irrotationnels. Par cet outil, nous avons réussi à retrouver les résultats de Taylor sur l'instabilité des gouttes sous champ uniforme. Les résultats du déplacement des gouttes sous champ non uniforme montrent un bon accord également entre les simulations et des modèles analytiques approchés. L'état de développement de l'outil MIF nous permet d'envisager son extension vers des problèmes électrohydrodynamiques encore plus riches.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Association of baseline soluble immune checkpoints with the risk of relapse in PR3-ANCA vasculitis following induction of remission.

OBJECTIVES: We investigated whether soluble immune checkpoints (sICPs) predict treatment resistance, relapse and infections in patients with antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). METHODS: Plasma sICP concentrations from available samples obtained during conduct of the RAVE trial were measured by immunoabsorbent assays from patients with either proteinase 3 (PR3) or myeloperoxidase (MPO)-ANCA vasculitis and were correlated with clinical outcomes, a set of biomarkers and available flow cytometry analyses focusing on T cell subsets. Log-rank test was used to evaluate survival benefits, and optimal cut-off values of the marker molecules were calculated using Yeldons J. RESULTS: Analysis of 189 plasma samples at baseline revealed higher concentrations of sTim-3, sCD27, sLag-3, sPD-1 and sPD-L2 in patients with MPO-ANCA vasculitis (n=62) as compared with PR3-ANCA vasculitis (n=127). Among patients receiving rituximab induction therapy (n=95), the combination of lower soluble (s)Lag-3 (3000 pg/mL) predicted therapy failure. Twenty-four out of 73 patients (32.9%) in the rituximab arm reaching remission at 6 months relapsed during follow-up. In this subgroup, high baseline values of sTim-3 (>1200 pg/mL), sCD27 (>1250 pg/mL) and sBTLA (>1000 pg/mL) were associated with both sustained remission and infectious complications. These findings could not be replicated in 94 patients randomised to receive cyclophosphamide/azathioprine. CONCLUSIONS: Patients with AAV treated with rituximab achieved remission less frequently when concentrations of sLag-3 were low and concentrations of sCD27 were high. Higher concentrations of sTim-3, sCD27 and sBTLA at baseline predicted relapse in patients treated with rituximab. These results require confirmation but may contribute to a personalised treatment approach of AAV

All-inkjet-printed bottom-gate thin-film transistors using UV curable dielectric for well-defined source-drain electrodes

Technological restrictions of the inkjet printing technology for printed electronics can hinder its application potential, mainly due to the limited resolution and layer homogeneity in comparison to conventional manufacturing techniques for electronics. The manufacturing of active devices such as thin-film transistors with appropriate performance using printing technologies is still one of the current challenges towards industrial applications. This work demonstrates the application of an ultraviolet (UV) curable ink as insulating material for the gate dielectric. The advantage of the UV curable ink is its fast curing and the smooth surface enabling high resolution patterns on top of it. In this way, all-inkjet-printed organic thin-film transistors (OTFTs) were fabricated with silver electrodes, UV curable gate dielectric, and 6,13-bis(triisopropylsilylethynyl)pentacene for the active semiconductor layer. By fine tuning of processing parameters and pattern geometries, a stable channel length of about 10 μm was obtained in the bottom-gate configuration without the need of additional steps, suggesting a way to build low-cost all-inkjet-printed OTFTs with well-defined source-drain electrodes and fast UV curable dielectric without any additional steps. The inkjet-printed device is characterized by an electron mobility of 0.012 cm2 V−1 s−1 and on/off ratio of 103.This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2011 and the project PTDC/CTM-NAN/121038/2010. The authors are also grateful for funding from "Matepro-Optimizing Materials and Processes", ref. "NORTE-07-0124-FEDER-000037", co-funded by the "Programa Operacional Regional do Norte" (ON. 2 - O Novo Norte), under the "Quadro de Referencia Estrategico Nacional" (QREN), through the "Fundo Europeu de Desenvolvimento Regional" (FEDER). Helder Castro thanks for the support of the FCT under grant SFRH/BDE/33350/2008. The authors acknowledge Dr. Fulvia Villani at ENEA, Italy, for measurements and discussions of surface roughness

Geographies of education and the significance of children, youth and families

This paper engages with Hanson Thiem's (2009) critique of geographies of education. Accepting the premise that education warrants fuller attention by geographers, the paper nonetheless argues that engaging with research on children, youth and families reshapes understanding of what has been, and might be, achieved. Foregrounding young people as the subjects rather than objects of education demands that attention be paid to their current and future life-worlds, in both inward and outward looking geographies of education. It also requires a broadening of our spatial lens, in terms of what 'count' as educational spaces, and the places where we study these