Questo progetto di ricerca ha beneficiato di un finanziamento del Consiglio europeo della ricerca nell&#39;ambito del Settimo programma quadro della Comunità europea (FP7/2007-2013) / ERC convenzione di sovvenzione n ° 242710 ed è stata inoltre sostenuta dalla Human Frontier Science Program e il programma Emmy Noether del tedesco 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>

Nessun conflitto di interessi dichiarati.

Aspetti critici nella preparazione di xeno iperpolarizzato sono impurità ossigeno nel collettore di gas tra la cella di pompaggio ed una sufficiente illuminazione della cella con luce polarizzata circolarmente. La suddetta prova lampadina è un modo semplice per rilevare le concentrazioni di ossigeno deleteri durante il trasferimento rubidio. Il metallo alcalino può perdere la sua superficie lucida dal momento dell&#39;installazione della cella nel polarizzatore. Tuttavia, vaporizzazione sufficiente di Rb non ossidato...

Agenti iperpolarizzato stanno guadagnando crescente attenzione per NMR / MRI applicazioni poiché possono risolvere il problema della sensibilità in determinate circostanze 2. Tre approcci principali sono attualmente utilizzati (polarizzazione nucleare dinamica, DNP, para-idrogeno polarizzazione indotta, PHIP e girare lo scambio pompaggio ottico, SEOP) che tutti preparare un aumentato artificialmente differenza di popolazione di spin di fuori di un magnete NMR prima della spettroscopia reale o esperimento di imaging . Qui si descrive la funzione e il funzionamento di una configurazione SEOP che è stato ottimizzato per la produzione di 129 Xe iperpolarizzato usati negli esperimenti stato di soluzione. Un componente essenziale è una fonte di luce intensa che emette fotoni infrarossi a 795 nm. Array di diodi laser (LDA) sono dispositivi convenienti che offrono un&#39;elevata potenza&gt; 100 W a costi ragionevoli. In molte configurazioni, la LDA emette in una fibra ottica che più o meno mantiene la polarizzazione di the luce laser. Per garantire un processo sufficiente SEOP questa polarizzazione ellittica deve essere convertito in polarizzazione circolare di elevata purezza. Componenti principali delle ottiche di polarizzazione sono mostrate nelle Figure 1 e 2 e la configurazione del sistema è illustrata schematicamente in film complementare 1. Per polarizzare la luce circolarmente abbiamo prima collegare l&#39;estremità della fibra ottica primaria di un fascio di espansione (ad esempio, un collimatore di fibre) per ridurre la densità di potenza. La luce passa attraverso un cubo beam splitter polarizzatore, generando luce linearmente polarizzata. Ruotando questo cubo si può determinare l&#39;asse preferita della polarizzazione residua con un misuratore di potenza. Trasmissione massimo corrisponde alla situazione in cui è allineato all&#39;asse veloce del cubo con l&#39;asse principale polarizzazione della luce. Cubi con coefficienti di estinzione elevate (100.000: 1 o superiore) ottenere una buona separazione di componenti di polarizzazione. Questo può essere testatoutilizzando un secondo divisore di fascio cubo come un analizzatore che viene ruotato mentre la prima è allineata per la massima trasmissione del fascio straordinario. Una volta che la polarizzazione lineare della luce trasmessa è stato confermato, un onda λ / 4 piastra progettato per 795 nm viene introdotto nella straordinaria fascio lineare per convertire in polarizzazione circolare. A questo scopo, l&#39;asse veloce della piastra onda è ruotato di 45 ° rispetto all&#39;asse del fascio cubo splitter veloce. (Se desiderato, polarizzazione circolare del fascio riflesso ordinaria con asse di polarizzazione lineare perpendicolare alla straordinaria fascio può essere realizzato in modo simile.) La qualità della polarizzazione circolare può essere testato con un cubo secondo divisore di fascio che deve cedere alla rotazione di trasmissione costante. A secondarie ottica di espansione del fascio (ad esempio due lenti in una configurazione telescopio galileiano) aumenta quindi il diametro del fascio per lo illuminate la cella di vetro per il processo di pompaggio all&#39;interno di una scatola forno. Assorbimento della luce laser da Rb vapore nella cella viene monitorata attraverso un foro di perno dietro la cella di pompaggio alla fine della scatola: un collimatore raccoglie un fascio IR attenuato da analizzare con uno spettrometro ottico (vedere Figura 3 per il pompaggio di impostazione cella ). Un meccanismo di riscaldamento all&#39;esterno della cella di pompaggio vaporizza parzialmente una gocciolina Rb seduto all&#39;interno della cellula (figura 4a) e pertanto causa di assorbimento della luce laser. Densità del vapore può essere regolato tramite il punto di riscaldamento impostata del regolatore PID corrispondente. Le alte temperature (ca. 190 ° C) sono buoni per configurazioni compatte in cui il xeno ha una quantità limitata di tempo per costruire la polarizzazione. La miscela di gas contenente Xe, N 2 e Lui scorre attraverso la cella di pompaggio opposta alla direzione del fascio laser (Figura 3). Un campo magnetico esterno allineato con il raggio laser assicura che esimoelettroniche fotoni IR sono solo pompando una transizione Rb. Rilassamento degli stati dell&#39;elettrone è veloce e deve essere non radiativo per evitare l&#39;emissione di fotoni IR con polarizzazione &#39;sbagliato&#39;. Qui, il 2 N entra in gioco come gas quench. Alla fine, il sistema Rb costruisce una sovrappopolazione di uno dei sottolivelli esporre il motivo mentre l&#39;altra viene continuamente impoverito dal laser (Figura 5). Xenon entrare in stretto contatto con gli atomi di Rb esperienze di spin-spin interazioni e la polarizzazione di spin dell&#39;elettrone è trasferito su nuclei Xe in flip-flop processi. Il gas iperpolarizzato fuoriesce dalla cella di pompaggio contiene tracce di Rb vapore che condensa sulla parete dei condotti entro pochi cm di presa a causa della bassa temperatura (simile alla Figura 4b). In applicazioni in vivo, tuttavia, richiederebbe ulteriore eliminazione del metallo alcalino (ad esempio attraverso una trappola a freddo), mentre in vitro experiments possono essere effettuati in modo sicuro con il gas come lascia il hyperpolarizer. Tubazione Teflon collega l&#39;uscita polarizzatore con l&#39;ingresso di un apparato di vetro per eseguire esperimenti NMR su soluzioni di test. Controllori di flusso di massa sono utilizzati per regolare la quantità di Xe scorre nella configurazione NMR. Essi sono attivati ​​da comandi nella sequenza di impulsi NMR. Dopo aver controllato la valorizzazione polarizzazione raggiunto, il gas può essere utilizzato come NMR / MRI agente di contrasto in esperimenti stato di soluzione. Xe ha una certa solubilità in acqua (4,5 mM / atm) e altri solventi. Pertanto, esso può già fungere da solo come agente di contrasto per visualizzare la distribuzione di alcuni liquidi. Tuttavia, è anche possibile collegare la NMR-attivo nuclei di certe molecole per acquisire informazioni specifiche molecolare attraverso il gas altrimenti inerte. Fornendo un host molecolare per la disciolto Xe, è possibile conferire specificità molecolare al segnale Xe NMR. Ciò offre l&#39;opportunità diprogettazione agenti di contrasto funzionalizzati - chiamato anche biosensori - quando una tale struttura ospitante è accoppiato ad un&#39;unità di targeting che si lega a specifici analiti di interesse biomedico (Figura 6). Ulteriore miglioramento della sensibilità è necessaria quando il biosensore deve essere rilevata a concentrazioni che sono bassi per mezzi di contrasto MR (&lt;100 pM). Ciò può essere ottenuto mediante trasferimento scambio chimico saturazione (CEST). Questo metodo rileva il biosensore indirettamente distruggendo la magnetizzazione della gabbia Xe e osservando la variazione del segnale di Xe libera in soluzione. Dal momento che i nuclei iperpolarizzato sono continuamente sostituite dopo qualche ms 10, molti 100-1000 trasferimento di nuclei le informazioni sulla piscina rilevato e amplificare il segnale di ca. 10 3 volte (vedi filmato 2).

<table border="1"><tbody><tr><td> Nome del reagente </td><td> Azienda </td><td> Numero di catalogo </td><td> Commenti (opzionale) </td></tr><tr><td> Rb lingotto </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> Sistema laser </td><td> Laser QPC / Operazioni laser </td><td> BrightLock 50 </td><td></td></tr><tr><td> Sistema di vuoto </td><td> Pfeiffer </td><td> HiCube </td><td></td></tr><tr><td> Termocoppie </td><td> NewportOmega </td><td> SA2F-KI-3M </td><td></td></tr><tr><td> Silicon riscaldatore </td><td> Newport Omega </td><td> FMA5514 </td><td></td></tr><tr><td> Trasduttore di pressione </td><td> Newport Omega </td><td> PR 33X-V-10 </td><td></td></tr><tr><td> Processo metro </td><td> Newport Omega </td><td> INFCP-100B </td><td></td></tr><tr><td> Controllori di flusso di massa </td><td> Newport Omega </td><td> MFC </td><td></td></tr><tr><td> Regolatori PID </td><td> Newport Omega </td><td> CN7800 </td><td></td></tr><tr><td> Software di controllo </td><td> Newport Omega </td><td> DASYLab </td><td></td></tr><tr><td> Acquisizione dati </td><td> Newport Omega </td><td> Daqboard 3000 </td><td></td></tr><tr><td> Sensore di vuoto </td><td> Oerlikon </td><td> TTR91 </td><td></td></tr><tr><td> Controllore di Vuoto </td><td> Vacom </td><td> MVC-3 </td><td></td></tr><tr><td> Larghezza collimatore </td><td> Thorlabs </td><td> F810SMA-780 </td><td></td></tr><tr><td> Polarizzatore beam splitter cubo </td><td> Thorlabs </td><td> GL15-B </td><td></td></tr><tr><td> Piastra λ / 4 d&#39;onda </td><td> Thorlabs </td><td> WPQ10M-780 </td><td></td></tr><tr><td> Larghezza di espansione lenti </td><td> Thorlabs </td><td></td><td></td></tr><tr><td> Spettrometro ottico </td><td> Ocean Optics </td><td> HR4000 </td><td></td></tr><tr><td> Fibra ottica </td><td> Ocean Optics </td><td></td><td></td></tr><tr><td> Bassa pressione del tubo NMR </td><td> Wilmad </td><td> 513-7LPV-7 </td><td></td></tr><tr><td> NMR tubo 5 millimetri </td><td> Sigma-Aldrich </td><td> HX58.1 </td><td></td></tr><tr><td> Bobine di Helmholtz </td><td> Phywe </td><td> 06960-00 </td><td></td></tr><tr><td> Fused silica capillari </td><td> Polymicro </td><td> TSG 250350 </td><td></td></tr></tbody></table>

hyperpolarized xenon for nmr and mri applications

Risonanza magnetica nucleare (NMR) e di imaging (MRI) che soffrono di bassa sensibilità intrinseca perché i campi magnetici esterni, anche forti di ~ 10 T generare solo un piccolo rilevabile rete magnetizzazione del campione a temperatura ambiente 1. Quindi, la maggior parte delle applicazioni NMR e MRI basano sulla rilevazione di molecole ad alta concentrazione relativa (ad esempio, acqua per l&#39;imaging di tessuto biologico) o richiedono tempi di acquisizione eccessivi. Questo limita la nostra capacità di sfruttare la specificità molto utile molecolare di segnali NMR per molte applicazioni biochimiche e mediche. Tuttavia, nuovi approcci sono emersi negli ultimi anni: Manipolazione delle specie di spin identificati prima del rilevamento all&#39;interno del NMR / MRI magnete in grado di aumentare la magnetizzazione e quindi consente il rilevamento di molecole in concentrazione molto più bassa 2. Qui, presentiamo un metodo di polarizzazione di una miscela di gas xenon (Xe 2-5%, 10%N 2, Egli saldo) in una configurazione compatta con un ca. 16000-volte amplificazione dei segnali. Moderna linea criterio diodi laser consentono polarizzazione efficiente 7 e immediato utilizzo di miscela di gas anche se il gas nobile non è separato dagli altri componenti. L&#39;apparato SEOP è spiegato e determinazione della polarizzazione di spin raggiunta è dimostrata per il controllo delle prestazioni del metodo. Il gas iperpolarizzato può essere utilizzata per l&#39;imaging spazio vuoto, tra cui l&#39;imaging del flusso di gas o studi di diffusione alle interfacce con altri materiali 8,9. Inoltre, il segnale Xe NMR è estremamente sensibile al suo ambiente molecolare 6. In questo modo la possibilità di utilizzarlo come NMR / MRI agente di contrasto quando disciolto in soluzione acquosa con funzionalizzati host molecolari che temporaneamente intrappolare il gas 10,11. Rilevazione diretta e ad alta sensibilità di rilevazione indiretta di tali costrutti è dimostrato sia in modalità spettroscopica e di imaging. &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 produzione di xeno iperpolarizzato mediante scambio di spin ottica di pompaggio (SEOP) è descritto. Questo metodo produce un 10000-volte valorizzazione ~ della polarizzazione di spin nucleare di Xe-129 e ha applicazioni in spettroscopia di risonanza magnetica nucleare e di imaging. Esempi di fase gas ed esperimenti stato di soluzione sono dati.

Xenon iperpolarizzato per NMR e applicazioni MRI

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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19.4K Views.  Leibniz-Institut für Molekulare Pharmakologie. La produzione di xeno iperpolarizzato mediante scambio di spin ottica di pompaggio (SEOP) è descritto. Questo metodo produce un 10000-volte valorizzazione ~ della polarizzazione di spin nucleare di Xe-129 e ha applicazioni in spettroscopia di risonanza magnetica nucleare e di imaging. Esempi di fase gas ed esperimenti stato di soluzione sono dati.

Video: 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.

A stato solido innesto elettroliti Copolimero per Batterie di litio Applicazioni

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.

L&#39;uso di un multi-comparto dinamico singolo enzima Phantom per gli Studi di hyperpolarized Risonanza Magnetica Agents

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.

Tridimensionale Velocimetry monitoraggio di particelle per applicazioni Turbulence: caso di flusso 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.

Colloidale Sintesi di Nanopatch Antenne per applicazioni in Plasmonics e nanofotonica

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.

Fabbricazione di microsfere di polimeri per risonatore ottico e applicazioni 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.

Protocollo per la valutazione di MRI artefatti causati da metallo impianti per valutare l'idoneità degli impianti e la vulnerabilità delle sequenze di impulsi

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.

Fabbricazione di superfici superidrofobiche metalliche per applicazioni Anti-Icing

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.

Nucleazione controllabile di cavitazione da nanoparticelle plasmoniche d'oro per l'aumento ad alta intensità focalizzato applicazioni ad ultrasuoni

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.

Ottimizzazione, Test e diagnostica di propulsori a effetto Hall miniaturizzato

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.

Applicazione di un agente di accoppiamento per migliorare le proprietà dielettriche dei nanocompositi basati su polimeri

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