Ce projet de recherche a été financée par le Conseil européen de la recherche au titre du programme de la Communauté européenne septième programme-cadre (FP7/2007-2013) / ERC convention de subvention n ° 242710 et a en outre été soutenu par le Human Frontier Science Program et le Programme d&#39;Emmy Noether de l&#39;allemand Research Foundation (SCHR 995/2-1).

<ol>
	<li>Schr&#246;der, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenon+for+NMR+biosensing+-+Inert+but+alert.">Xenon for NMR biosensing - Inert but alert.</a> Phys Med. , (2011).</li><li>Viale, A., Reineri, F., Santelia, D., Cerutti, E., Ellena, S., Gobetto, R., Aime, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperpolarized+agents+for+advanced+MRI+investigations.">Hyperpolarized agents for advanced MRI investigations.</a> Q J Nucl. Med. Mol. Imaging. 53, 604-617 (2009).</li><li>Walker, T. G., Happer, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin-exchange+optical+pumping+of+noble-gas+nuclei.">Spin-exchange optical pumping of noble-gas nuclei.</a> Rev. Mod. Phys. 69, 629-642 (1997).</li><li>Albert, M. S., Cates, G. D., Driehuys, B., Happer, W., Saam, B., Springer, C. S., Wishnia, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+magnetic+resonance+imaging+using+laser-polarized+129Xe.">Biological magnetic resonance imaging using laser-polarized 129Xe.</a> Nature. 370, 199-201 (1994).</li><li>Cherubini, A., Bifone, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperpolarised+xenon+in+biology.">Hyperpolarised xenon in biology.</a> Progr. NMR Spectrosc. 42, 1-30 (2003).</li><li>Goodson, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+magnetic+resonance+of+laser-polarized+noble+gases+in+molecules,+materials,+and+organisms.">Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials, and organisms.</a> J. Magn. Reson. 155, 157-216 (2002).</li><li>Nikolaou, P., Whiting, N., Eschmann, N. A., Chaffee, K. E., Goodson, B. M., Barlow, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+laser-polarized+xenon+using+fiber-coupled+laser-diode+arrays+narrowed+with+integrated+volume+holographic+gratings.">Generation of laser-polarized xenon using fiber-coupled laser-diode arrays narrowed with integrated volume holographic gratings.</a> J. Magn. Reson. 197, 249-254 (2009).</li><li>Ruppert, K., Brookeman, J. R., Hagspiel, K. D., Mugler, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+lung+physiology+with+xenon+polarization+transfer+contrast+(XTC).">Probing lung physiology with xenon polarization transfer contrast (XTC).</a> Magn. Reson. Med. 44, 349-357 (2000).</li><li>Driehuys, B., Cofer, G. P., Pollaro, J., Mackel, J. B., Hedlund, L. W., Johnson, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+alveolar-capillary+gas+transfer+using+hyperpolarized+129Xe+MRI.">Imaging alveolar-capillary gas transfer using hyperpolarized 129Xe MRI.</a> Proc. Natl. Acad. Sci. U.S.A. 103, 18278-18283 (2006).</li><li>Spence, M. M., Rubin, S. M., Dimitrov, I. E., Ruiz, E. J., Wemmer, D. E., Pines, A., Yao, S. Q., Tian, F., Schultz, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functionalized+xenon+as+a+biosensor.">Functionalized xenon as a biosensor.</a> Proc. Natl. Acad. Sci. U.S.A. 98, 10654-10657 (2001).</li><li>Schr&#246;der, L., Lowery, T. J., Hilty, C., Wemmer, D. E., Pines, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+imaging+using+a+targeted+magnetic+resonance+hyperpolarized+biosensor.">Molecular imaging using a targeted magnetic resonance hyperpolarized biosensor.</a> Science. 314, 446-449 (2006).</li><li>Schrank, G., Ma, Z., Schoeck, A., Saam, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+low-pressure+high-capacity+129Xe+flow-through+polarizer.">Characterization of a low-pressure high-capacity 129Xe flow-through polarizer.</a> Phys. Rev. A. 80, 063424 (2009).</li><li>Levron, D., Walter, D. K., Appelt, S., Fitzgerald, R. J., Kahn, D., Korbly, S. E., Sauer, K. E., Happer, W., Earles, T. L., Mawst, L. J., Botez, D., Harvey, M., DiMarco, L., Connolly, J. C., M&#246;ller, H. E., Chen, X. J., Cofer, G. P., Johnson, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+resonance+imaging+of+hyperpolarized+129Xe+produced+by+spin+exchange+with+diode-laser+pumped+Cs.">Magnetic resonance imaging of hyperpolarized 129Xe produced by spin exchange with diode-laser pumped Cs.</a> Appl. Phys. Lett. 73, 2666 (1998).</li><li>Zhou, X., Sun, X. P., Luo, J., Zeng, X. Z., Liu, M. L., Zhan, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+Hyperpolarized+129Xe+Gas+Without+Nitrogen+by+Optical+Pumping+at+133Cs+D2+Line+in+Flow+System.">Production of Hyperpolarized 129Xe Gas Without Nitrogen by Optical Pumping at 133Cs D2 Line in Flow System.</a> Chin. Phys. Lett. 21, 1501-1503 (2004).</li><li>Zhou, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperpolarized+noble+gases+as+contrast+agents.">Hyperpolarized noble gases as contrast agents.</a> Methods Mol. Biol. 771, 189-204 (2011).</li><li>Seltzer, S. J., Michalak, D. J., Donaldson, M. H., Balabas, M. V., Barber, S. K., Bernasek, S. L., Bouchiat, M. A., Hexemer, A., Hibberd, A. M., Kimball, D. F., Jaye, C., Karaulanov, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+antirelaxation+coatings+for+alkali-metal+vapor+cells+using+surface+science+techniques.">Investigation of antirelaxation coatings for alkali-metal vapor cells using surface science techniques.</a> J. Chem. Phys. 133, 144703 (2010).</li></ol>

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Aspects critiques dans la préparation de xénon hyperpolarisé sont des impuretés d&#39;oxygène dans le collecteur de gaz, y compris la cellule de pompage et un éclairage suffisant de la cellule avec une lumière polarisée circulairement. Le test de lumière au-dessus mentionnée ampoule est un moyen simple de détecter des concentrations d&#39;oxygène nuisibles pendant le transfert de rubidium. Le métal alcalin peut perdre sa surface brillante au moment où la cellule est installé dans le polariseur. Cependant,...

Hyperpolarisés agents bénéficient d&#39;une attention croissante de RMN / IRM applications, car ils peuvent résoudre le problème de sensibilité dans certaines circonstances 2. Trois grandes approches sont actuellement utilisées (Polarisation dynamique nucléaire, DNP, para-hydrogène polarisation induite, PHIP et tourner échange de pompage optique, PDES) que tout préparer une différence de rotation augmenter artificiellement la population en dehors d&#39;un aimant RMN avant la spectroscopie réelle ou expérience d&#39;imagerie . Nous décrivons ici la fonction et le fonctionnement d&#39;une installation PDES qui a été optimisé pour la production de 129 Xe hyperpolarisé utilisés dans des expériences état ​​de solution. Un élément essentiel est une source intense de lumière émettant des photons infrarouges à 795 nm. Réseaux de diodes laser (LDA) sont des dispositifs pratiques qui offrent puissance de sortie élevée&gt; 100 W à un coût raisonnable. Dans de nombreuses configurations, l&#39;ADL émet dans une fibre optique qui conserve plus ou moins de la polarisation èmee lumière laser. Afin de garantir un processus PDES suffisamment cette polarisation elliptique doit être convertie en polarisation circulaire d&#39;une grande pureté. Les principaux composants de l&#39;optique de polarisation sont présentés dans les figures 1 et 2 et la mise en place du système est expliqué schématiquement en 1 film supplémentaire. Pour polariser la lumière circulairement nous attacher d&#39;abord l&#39;extrémité de fibre optique à un faisceau primaire d&#39;extension (par exemple, un collimateur de fibres) pour réduire la densité de puissance. La lumière traverse ensuite un cube séparateur de faisceau polarisant, générer de la lumière polarisée linéairement. En tournant ce cube, nous pouvons déterminer l&#39;axe préférentiel de la polarisation restante avec un wattmètre. Transmission maximale correspond à la situation où l&#39;axe rapide du cube est aligné avec l&#39;axe de polarisation de la lumière principale. Cubes avec des coefficients d&#39;extinction élevés (100.000: 1 ou mieux), on obtient une bonne séparation des composantes de polarisation. Cela peut être testéà l&#39;aide d&#39;un cube séparateur de faisceau en tant que deuxième analyseur qui est mis en rotation alors que le premier est aligné pour la transmission maximale du faisceau extraordinaire. Une fois la polarisation linéaire de la lumière transmise a été confirmée, d&#39;une lame d&#39;onde λ / 4 conçu pour 795 nm est introduite dans le faisceau extraordinaire pour convertir linéaire en une polarisation circulaire. A cet effet, l&#39;axe rapide de la lame d&#39;onde est mis en rotation par 45 ° par rapport à l&#39;axe du faisceau cube séparateur rapide. (Si on le souhaite, la polarisation circulaire du faisceau réfléchi ordinaire avec son axe perpendiculaire polarisation linéaire du faisceau extraordinaire peut être réalisé d&#39;une manière similaire.) La qualité de la polarisation circulaire peut être testé avec un cube séparateur de faisceau deuxième devrait produire de transmission constant lors de la rotation. A optique secondaire d&#39;expansion du faisceau (par exemple, deux lentilles dans une configuration lunette de Galilée) puis augmente le diamètre du faisceau complètement illuminate la cellule de verre pour le processus de pompage à l&#39;intérieur d&#39;une boîte de four. L&#39;absorption de la lumière laser par Rb vapeur dans la cellule est contrôlée par un trou d&#39;épingle derrière la cellule de pompage à la fin de la boîte: un collimateur recueille un faisceau atténué IR pour être analysés avec un spectromètre optique (voir figure 3 pour le pompage de configuration cellule ). Un mécanisme de chauffage extérieur de la cellule de pompage se vaporise partiellement une goutte Rb assis à l&#39;intérieur de la cellule (figure 4a) et provoque donc l&#39;absorption de la lumière laser. La densité de la vapeur peut être réglée par l&#39;intermédiaire du point de consigne de chauffage du régulateur PID respectif. Des températures élevées (environ 190 ° C) sont bonnes pour les configurations compactes où le xénon a une quantité limitée de temps pour bâtir la polarisation. Le mélange gazeux contenant de Xe, N 2 et il s&#39;écoule à travers la cellule de pompage opposée à la direction du faisceau laser (figure 3). Un champ magnétique externe aligné avec le faisceau laser assure èmee photons infrarouges sont seulement une transition de pompage Rb. Relaxation des états d&#39;électrons est rapide et doivent être non-radiatif d&#39;éviter l&#39;émission de photons IR avec «mauvaise» la polarisation. Ici, le 2 N arrive en jeu comme un gaz de trempe. Finalement, le système Rb s&#39;accumule une surpopulation de l&#39;un des sous-niveaux d&#39;état de base tandis que l&#39;autre est en permanence appauvri par le laser (figure 5). Xénon entrer en contact étroit avec les atomes de Rb expériences de spin-spin et les interactions de la polarisation de spin électronique est transféré sur les noyaux Xe dans la bascule processus. Le gaz hyperpolarisé sortant de la cellule de pompage contient des traces de vapeur Rb que la condensation sur la paroi du tube à l&#39;intérieur de quelques centimètres de la sortie en raison de la basse température (similaire à la figure 4b). Dans les applications in vivo, cependant, exigerait l&#39;élimination supplémentaire du métal alcalin (par exemple dans un piège à froid), alors que in vitro experiments peut être effectuée en toute sécurité avec le gaz à la sortie de la hyperpolarizer. Tube en téflon relie la sortie avec le polariseur d&#39;entrée d&#39;un appareil en verre pour réaliser des expériences RMN des solutions d&#39;essai. Régulateurs de débit massique sont utilisées pour ajuster la quantité de Xe s&#39;écoulant dans la configuration de RMN. Elles sont déclenchées par des commandes dans la séquence d&#39;impulsions de RMN. Après vérification de la mise en valeur de polarisation atteint, le gaz peut être utilisé comme agent de contraste RMN / IRM dans les expériences de l&#39;état de solution. Xe a une certaine solubilité dans l&#39;eau (4,5 mM / atm) et d&#39;autres solvants. Il a donc peut déjà servir à lui seul comme agent de contraste pour visualiser la répartition de certains liquides. Toutefois, il est également possible de relier les noyaux de RMN-actif à certaines molécules afin d&#39;acquérir des informations spécifiques moléculaire à travers le gaz inerte par ailleurs. Par la fourniture d&#39;un hôte moléculaire pour la Xe dissous, il est possible de conférer une spécificité moléculaire au signal de RMN Xe. Cela offre la possibilité d&#39;des agents de contraste fonctionnalisés de conception - également appelé biocapteurs - quand une telle structure hôte est couplé à une unité de ciblage qui se lie à des analytes présentant un intérêt biomédical (figure 6). Accroissement de la sensibilité plus poussée est nécessaire lorsque le biocapteur doit être détecté à des concentrations qui sont faibles pour les agents de contraste IRM (&lt;100 uM). Ceci peut être réalisé par échange chimique saturation de transfert (CET). Cette méthode détecte le biocapteur indirectement par destruction de l&#39;aimantation de la cage Xe et en observant la variation du signal de Xe libre en solution. Depuis les noyaux hyperpolarisés sont continuellement remplacés après quelques 10 ms, un grand nombre de 100 à 1000 germes de transfert de l&#39;information détectée sur la piscine et amplifier le signal de ca. 10 3 fois (voir le film 2).

<table border="1"><tbody><tr><td> Nom du réactif </td><td> Entreprise </td><td> Numéro de catalogue </td><td> Commentaires (optionnel) </td></tr><tr><td> Lingot Rb </td><td> Sigma-Aldrich </td><td> 276332-1G </td><td></td></tr><tr><td> P 4 O 10 </td><td> Sigma-Aldrich </td><td> 79610-500G </td><td></td></tr><tr><td> Ar </td><td> Praxair </td><td></td><td></td></tr><tr><td> Xe </td><td> Sigma-Aldrich </td><td> 00472-1EA </td><td></td></tr><tr><td> O 2 </td><td> Sigma-Aldrich </td><td> 00476-1EA </td><td></td></tr><tr><td> Système de laser </td><td> Lasers QPC / Opérations laser </td><td> Brightlock 50 </td><td></td></tr><tr><td> Système à vide </td><td> Pfeiffer </td><td> HiCube </td><td></td></tr><tr><td> Thermocouples </td><td> NewportOméga </td><td> SA2F-KI-3M </td><td></td></tr><tr><td> Chauffe-silicium </td><td> Newport Omega </td><td> FMA5514 </td><td></td></tr><tr><td> Transducteur de pression </td><td> Newport Omega </td><td> PR 33X-V-10 </td><td></td></tr><tr><td> Mètre processus </td><td> Newport Omega </td><td> INFCP-100B </td><td></td></tr><tr><td> Contrôleurs de débit massique </td><td> Newport Omega </td><td> MFC </td><td></td></tr><tr><td> Régulateurs PID </td><td> Newport Omega </td><td> CN7800 </td><td></td></tr><tr><td> Logiciel de contrôle </td><td> Newport Omega </td><td> DASYLab </td><td></td></tr><tr><td> L&#39;acquisition des données </td><td> Newport Omega </td><td> Daqboard 3000 </td><td></td></tr><tr><td> Capteur de vide </td><td> Oerlikon </td><td> TTR91 </td><td></td></tr><tr><td> Régulateur de vide </td><td> Vacom </td><td> MVC-3 </td><td></td></tr><tr><td> Collimateur </td><td> Thorlabs </td><td> F810SMA-780 </td><td></td></tr><tr><td> Cube séparateur de faisceau polarisant </td><td> Thorlabs </td><td> GL15-B </td><td></td></tr><tr><td> plaque λ / 4 d&#39;onde </td><td> Thorlabs </td><td> WPQ10M-780 </td><td></td></tr><tr><td> Lentilles de dilatation du faisceau </td><td> Thorlabs </td><td></td><td></td></tr><tr><td> Spectromètre optique </td><td> Ocean Optics </td><td> HR4000 </td><td></td></tr><tr><td> Fibre optique </td><td> Ocean Optics </td><td></td><td></td></tr><tr><td> Faible tube RMN pression </td><td> Wilmad </td><td> 513-7LPV-7 </td><td></td></tr><tr><td> Tube RMN de 5 mm </td><td> Sigma-Aldrich </td><td> HX58.1 </td><td></td></tr><tr><td> Bobines de Helmholtz </td><td> Phywe </td><td> 06960-00 </td><td></td></tr><tr><td> Fused siliconeca capillaires </td><td> Polymicro </td><td> TSG 250350 </td><td></td></tr></tbody></table>

hyperpolarized xenon for nmr and mri applications

Résonance magnétique nucléaire (RMN) et l&#39;imagerie (IRM) souffrent d&#39;une faible sensibilité intrinsèque en raison même de fortes champs magnétiques externes de ~ 10 T ne génèrent qu&#39;une petite détectable net-aimantation de l&#39;échantillon à température ambiante 1. Par conséquent, la plupart des applications en RMN et IRM reposent sur ​​la détection de molécules à forte concentration relative (par exemple, de l&#39;eau pour l&#39;imagerie des tissus biologiques) ou nécessitent des temps d&#39;acquisition excessifs. Cela limite notre capacité d&#39;exploiter la spécificité moléculaire très utile des signaux RMN pour de nombreuses applications biochimiques et médicaux. Toutefois, de nouvelles approches ont vu le jour dans les dernières années: La manipulation des espèces spin détectés avant la détection à l&#39;intérieur de l&#39;aimant RMN / IRM peut considérablement augmenter l&#39;aimantation et donc permet la détection de molécules à des concentrations beaucoup plus faibles 2. Ici, nous présentons une méthode de polarisation d&#39;un mélange de gaz xénon (Xe 2-5%, 10%N 2, He équilibre) dans une configuration compacte avec un ca. L&#39;amélioration du signal 16000-pli. Lasers à diodes moderne ligne rétrécies permettre polarisation efficace 7 et une utilisation immédiate du mélange de gaz, même si le gaz noble n&#39;est pas séparé des autres composants. L&#39;appareil est expliqué PDES et la détermination de la polarisation de spin obtenue est mise en évidence pour le contrôle de l&#39;exécution du procédé. Le gaz hyperpolarisé peut être utilisé pour l&#39;imagerie espace vide, y compris l&#39;imagerie débit de gaz ou les études de diffusion aux interfaces avec d&#39;autres matériaux 8,9. En outre, le signal RMN Xe est extrêmement sensible à son environnement moléculaire 6. Cela permet à la possibilité de l&#39;utiliser comme agent de contraste RMN / IRM lorsqu&#39;il est dissous dans une solution aqueuse avec fonctionnalisés hôtes moléculaires temporairement emprisonner le gaz 10,11. La détection directe et haute sensibilité de détection indirecte de ces constructions est démontré à la fois en mode spectroscopique et d&#39;imagerie. &lt;/ P&gt;

Watch this Scientific Journal Video about Hyperpolarized Xenon for NMR and MRI Applications at JoVE.com

Hyperpolarized Xenon for NMR and MRI Applications

La production de xénon hyperpolarisé par le biais de spin optique d&#39;échange de pompage (PDES) est décrite. Cette méthode donne une ~ 10000-pli amélioration de la polarisation de spin nucléaire du Xe-129 et a des applications dans la spectroscopie par résonance magnétique nucléaire et d&#39;imagerie. Exemples de phase gazeuse et expériences état de solution sont donnés.

Xénon hyperpolarisé pour la RMN et l&#39;IRM Applications

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 ...

hyperpolarized-xenon-for-nmr-and-mri-applications

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Engineering

19.4K vues.  Leibniz-Institut für Molekulare Pharmakologie. La production de xénon hyperpolarisé par le biais de spin optique d'échange de pompage (PDES) est décrite. Cette méthode donne une ~ 10000-pli amélioration de la polarisation de spin nucléaire du Xe-129 et a des applications dans la spectroscopie par résonance magnétique nucléaire et d'imagerie. Exemples de phase gazeuse et expériences état de solution sont donnés.

Vidéo: Hyperpolarized Xenon for NMR and MRI Applications

Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (&lt;80 &deg;C), flammable, and volatile organic electrolytes. These organic based electrolyte systems are viable at ambient temperatures, but require a cooling system to ensure that temperatures do not exceed 80 &deg;C. These cooling systems tend to increase battery costs and can malfunction which can lead to battery malfunction and explosions, thus endangering human life. Increases in petroleum prices lead to a huge demand for safe, electric hybrid vehicles that are more economically viable to operate as oil prices continue to rise. Existing organic based electrolytes used in lithium ion batteries are not applicable to high temperature automotive applications. A safer alternative to organic electrolytes is solid polymer electrolytes. This work will highlight the synthesis for a graft copolymer electrolyte (GCE) poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature (Tg) poly(oxyethylene) acrylate (POEA). The conduction mechanism has been discussed and it has been demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence. Batteries containing commercially available LP30 organic (LiPF6 in ethylene carbonate (EC):dimethyl carbonate (DMC) at a 1:1 ratio) and GCE were cycled at ambient temperature. It was found that at ambient temperature, the batteries containing GCE showed a greater overpotential when compared to LP30 electrolyte. However at temperatures greater than 60 &deg;C, the GCE cell exhibited much lower overpotential due to fast polymer electrolyte conductivity and nearly the full theoretical specific capacity of 170 mAh/g was accessed.

Lithium ion batteries employ flammable and volatile organic electrolytes that are suitable for ambient temperature applications. A safer alternative to organic electrolytes are solid polymer batteries. Solid polymer batteries operate safely at high temperatures (&gt;120 &deg;C), thus making them applicable to high temperature applications such as deep oil drilling and hybrid electric vehicles. This paper will discuss (a) the polymer synthesis, (b) the polymer conduction mechanism, and (c) provide temperature cycling for both solid polymer and organic electrolytes.

Solid-state greffe électrolytes de copolymère pour le lithium applications de batteries

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (&lt;80 ...

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Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due to fundamental constraints imposed by the hyperpolarized state, exotic imaging and reconstruction techniques are commonly used. A practical system for characterization of dynamic, multi-spectral imaging methods is critically needed. Such a system must reproducibly recapitulate the relevant chemical dynamics of normal and pathological tissues. The most widely utilized substrate to date is hyperpolarized [1-13C]-pyruvate for assessment of cancer metabolism. We describe an enzyme-based phantom system that mediates the conversion of pyruvate to lactate. The reaction is initiated by injection of the hyperpolarized agent into multiple chambers within the phantom, each of which contains varying concentrations of reagents that control the reaction rate. Multiple compartments are necessary to ensure that imaging sequences faithfully capture the spatial and metabolic heterogeneity of tissue. This system will aid the development and validation of advanced imaging strategies by providing chemical dynamics that are not available from conventional phantoms, as well as control and reproducibility that is not possible in vivo.

A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

Utilisation d&#39;un multi-compartiment dynamique unique Enzyme Phantom pour les études de hyperpolarisé Agents de résonance magnétique

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due ...

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic recording of image sequences. The basic components, features, constraints and optimization tips of a 3D-PTV topology consisting of a high-speed camera with a four-view splitter are described and discussed in this article. The technique is applied to the intermediate flow field (5 &#60;x/d &#60;25) of a circular jet at Re &#8776; 7,000. Lagrangian flow features and turbulence quantities in an Eulerian frame are estimated around ten diameters downstream of the jet origin and at various radial distances from the jet core. Lagrangian properties include trajectory, velocity and acceleration of selected particles as well as curvature of the flow path, which are obtained from the Frenet-Serret equation. Estimation of the 3D velocity and turbulence fields around the jet core axis at a cross-plane located at ten diameters downstream of the jet is compared with literature, and the power spectrum of the large-scale streamwise velocity motions is obtained at various radial distances from the jet core.

A three-dimensional particle tracking velocimetry (3D-PTV) system based on a high-speed camera with a four-view splitter is described here. The technique is applied to a jet flow from a circular pipe in the vicinity of ten diameters downstream at Reynolds number Re &#8776; 7,000.

Trois dimensions Velocimetry de suivi des particules pour Turbulence Applications: Cas d&#39;un débit de jet

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic ...

Colloidal Synthesis of Nanopatch Antennas for Applications in Plasmonics and Nanophotonics

We present a method for colloidal synthesis of silver nanocubes and the use of these in combination with a smooth gold film, to fabricate plasmonic nanoscale patch antennas. This includes a detailed procedure for the fabrication of thin films with a well-controlled thickness over macroscopic areas using layer-by-layer deposition of polyelectrolyte polymers, namely poly(allylamine) hydrochloride (PAH) and polystyrene sulfonate (PSS). These polyelectrolyte spacer layers serve as a dielectric gap in between silver nanocubes and a gold film. By controlling the size of the nanocubes or the gap thickness, the plasmon resonance can be tuned from about 500 nm to 700 nm. Next, we demonstrate how to incorporate organic sulfo-cyanine5 carboxylic acid (Cy5) dye molecules into the dielectric polymer gap region of the nanopatch antennas. Finally, we show greatly enhanced fluorescence of the Cy5 dyes by spectrally matching the plasmon resonance with the excitation energy and the Cy5 absorption peak. The method presented here enables the fabrication of plasmonic nanopatch antennas with well-controlled dimensions utilizing colloidal synthesis and a layer-by-layer dip-coating process with the potential for low cost and large-scale production. These nanopatch antennas hold great promise for practical applications, for example in sensing, ultrafast optoelectronic devices and for high-efficiency photodetectors.

A protocol for the colloidal synthesis of silver nanocubes and fabrication of plasmonic nanoscale patch antennas with sub-10 nm gaps is presented.

Colloïdal Synthèse de Nanopatch Antennes pour Applications dans plasmonique et nanophotonique

We present a method for colloidal synthesis of silver nanocubes and the use of these in combination with a smooth gold film, to fabricate plasmonic ...

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, &#960;-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (&#181;-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, &#181;-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

Protocols for the synthesis of microspheres from polymers, the manipulation of microspheres, and micro-photoluminescence measurements are presented.

Fabrication de microsphères polymères pour résonateurs optiques et applications laser

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, ...

Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter metallic implant-related artifacts in MRI, resulting in reduced image quality. Therefore, the MRI suitability of implants in terms of artifact volume, as well as the development of pulse sequences to reduce image artifacts, are becoming more and more important. Here, we present a comprehensive protocol which allows for a standardized evaluation of the artifact volume of implants on MRI. Furthermore, this protocol can be used to analyze the vulnerability of different pulse sequences to artifacts. The proposed protocol can be applied to T1- and T2-weighted images with or without fat-suppression and all passive implants. Furthermore, the procedure enables the separate and three-dimensional identification of signal loss and pile-up artifacts. As previous investigations differed greatly in evaluation methods, the comparability of their results was limited. Thus, standardized measurements of MRI artifact volumes are necessary to provide better comparability. This may improve the development of the MRI suitability of implants and better pulse sequences to finally improve patient care.

We describe a standardized method to evaluate magnetic resonance imaging artifacts caused by implants to estimate the suitability of the implants for magnetic resonance imaging and/or the vulnerability of different pulse sequences to metallic artifacts simultaneously.

Protocole pour l’évaluation de MRI artefacts causés par le métal Implants pour évaluer les qualités des Implants et la vulnérabilité des séquences d’impulsions

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter ...

Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in industry. The wettability of the produced surface was analyzed by bouncing drop experiments and the topography was analyzed by confocal microscopy. In addition, we show various methodologies to measure its durability and anti-icing properties. Superhydrophobic surfaces hold a special texture that must be preserved to keep their water-repellency. To fabricate durable surfaces, we followed two strategies to incorporate a resistant texture. The first strategy is a direct incorporation of roughness to the metal substrate by acid etching. After this surface texturization, the surface energy was decreased by silanization or fluoropolymer deposition. The second strategy is the growth of a ceria layer (after surface texturization) that should enhance the surface hardness and corrosion resistance. The surface energy was decreased with a stearic acid film.
The durability of the superhydrophobic surfaces was examined by a particle impact test, mechanical wear by lateral abrasion, and UV-ozone resistance. The anti-icing properties were explored by studying the ability to repeal subcooled water, freezing delay, and ice adhesion.

We illustrate several methodologies to produce superhydrophobic metal surfaces and to explore their durability and anti-icing properties.

Fabrication de Surfaces superhydrophobes en métal pour Applications d’antigivrage

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in ...

Controllable Nucleation of Cavitation from Plasmonic Gold Nanoparticles for Enhancing High Intensity Focused Ultrasound Applications

In this study, plasmonic gold nanoparticles were simultaneously exposed to pulsed near-infrared laser light and high intensity focused ultrasound (HIFU) for the controllable nucleation of cavitation in tissue-mimicking gel phantoms. This in vitro protocol was developed to demonstrate the feasibility of this approach, for both enhancement of imaging and therapeutic applications for cancer. The same apparatus can be used for both imaging and therapeutic applications by varying the exposure duration of the HIFU system. For short duration exposures (10 &#181;s), broadband acoustic emissions were generated through the controlled nucleation of inertial cavitation around the gold nanoparticles. These emissions provide direct localization of nanoparticles. For future applications, these particles may be functionalized with molecular-targeting antibodies (e.g. anti-HER2 for breast cancer) and can provide precise localization of cancerous regions, complementing routine diagnostic ultrasound imaging. For continuous wave (CW) exposures, the cavitation activity was used to increase the localized heating from the HIFU exposures resulting in larger thermal damage in the gel phantoms. The acoustic emissions generated from inertial cavitation activity during these CW exposures was monitored using a passive cavitation detection (PCD) system to provide feedback of cavitation activity. Increased localized heating was only achieved through the unique combination of nanoparticles, laser light and HIFU. Further validation of this technique in pre-clinical models of cancer is necessary.

This protocol demonstrates the controllable nucleation of cavitation in gel phantoms, through simultaneous exposure to both near-infrared pulsed laser light and high intensity focused ultrasound (HIFU). The cavitation activity can then be used for enhancing imaging and/or therapeutic uses of HIFU.

Nucléation contrôlable de Cavitation de nanoparticules d’or plasmoniques pour renforcer la haute intensité porté Applications ultrasons

In this study, plasmonic gold nanoparticles were simultaneously exposed to pulsed near-infrared laser light and high intensity focused ultrasound (HIFU) ...

Optimization, Test and Diagnostics of Miniaturized Hall Thrusters

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without attendance and adjustment. Thermochemical thrusters which utilize thermodynamic properties of gases as a means of acceleration have physical limitations on their exhaust gas velocity, resulting in low efficiency. Moreover, these engines demonstrate extremely low efficiency at small thrusts and may be unsuitable for continuously operating systems which provide real-time adaptive control of the spacecraft orientation, velocity and position. In contrast, electric propulsion systems which use electromagnetic fields to accelerate ionized gases (i.e., plasmas) do not have any physical limitation in terms of exhaust velocity, allowing virtually any mass efficiency and specific impulse. Low-thrust Hall thrusters have a lifetime of several thousand hours. Their discharge voltage ranges between 100 and 300 V, operating at a nominal power of &lt;1 kW. They vary from 20 to 100 mm in size. Large Hall thrusters can provide fractions of millinewton of thrust. Over the past few decades, there has been an increasing interest in small mass, low power, and high efficiency propulsion systems to drive satellites of 50-200 kg. In this work, we will demonstrate how to build, test, and optimize a small (30 mm) Hall thruster capable of propelling a small satellite weighing about 50 kg. We will show the thruster operating in a large space environment simulator, and describe how thrust is measured and electric parameters, including plasma characteristics, are collected and processed to assess key thruster parameters. We will also demonstrate how the thruster is optimized to make it one of the most efficient small thrusters ever built. We will also address challenges and opportunities presented by new thruster materials.

Here, we present a protocol to test and optimize space propulsion systems based on miniaturized Hall-type thrusters.

Optimisation, de Test et de diagnostic des propulseurs miniaturisés Hall

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without ...

Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites

In this work, an easy, low-cost, and widely applicable method was developed to improve the compatibility between the ceramic fillers and the polymer matrix by adding 3-aminopropyltriethoxysilane (KH550) as a coupling agent during the fabrication process of BaTiO3-P(VDF-CTFE) nanocomposites through solution casting. Results show that the use of KH550 can modify the surface of ceramic nanofillers; therefore, good wettability on the ceramic-polymer interface was achieved, and the enhanced energy storage performances were obtained by a suitable amount of the coupling agent. This method can be used to prepare flexible composites, which is highly desirable for the production of high-performance film capacitors. If an excessive amount of coupling agent is used in the process, the non-attached coupling agent can participate in complex reactions, which leads to a decrease in dielectric constant and an increase in dielectric loss.

Here, we demonstrate a simple and low-cost solution-casting process to improve the compatibility between the filler and the matrix of polymer-based nanocomposites using surface modified BaTiO3 fillers, which can effectively enhance the energy density of the composites.

Application d’un agent de couplage pour améliorer les propriétés diélectriques des nanocomposites à base de polymères

In this work, an easy, low-cost, and widely applicable method was developed to improve the compatibility between the ceramic fillers and the polymer ...