Bu araştırma projesi Avrupa Topluluğu Yedinci Çerçeve Programı (FP7/2007-2013) / ERC hibe anlaşması n ° 242710 altında Avrupa Araştırma Konseyi fon aldı ve ayrıca İnsan Frontier Bilim Programı ve Alman Emmy Noether Programı tarafından desteklenmiştir Araştırma Vakfı (SCHR 995/2-1).

<ol>
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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>

Çıkar çatışması ilan etti.

Hyperpolarized ksenon hazırlanmasında kritik açıdan pompalama hücre ve dairesel polarize ışık ile hücrenin yeterli aydınlatma içeren gaz manifoldu oksijen yabancı maddeleri bulunmaktadır. Yukarıda bahsedilen ampul testi rubidyum aktarımı yaparken zararlı oksijen konsantrasyonlarının saptanması için basit bir yoludur. Alkali metal hücrenin polarize takılı zaman, parlak yüzeye kaybedebilirsiniz. . Bir defa, ancak, non-okside Rb, yeterli düşük buharlaşma lazer transmisyon (ilk kez için taze bi...

Belli koşullar altında 2 hassasiyet sorunu çözebilir yana Hyperpolarized ajanlar NMR / MRG uygulamaları için artan bir önem kazanmaktadır. Önceki bütün gerçek spektroskopi veya görüntüleme deneyi için NMR mıknatıs dışında bir yapay artış sıkma nüfus değişimi hazırlamak üç ana yaklaşım şu anda (ve döviz optik pompalama, Seop dönmeye;; para-hidrojen indüksiyon polarizasyonu, PHIP dinamik nükleer polarizasyon, DNP) kullanılır . Burada çözüm devlet Deneylerde kullanılan hyperpolarized 129 Xe üretimi için optimize edilmiş bir Seop kurulum fonksiyonu ve işletimi tarif. Temel bir bileşeni 795 nm kızılötesi foton yayan yoğun bir ışık kaynağıdır. Lazer diyot diziler (LDA), yüksek güç çıkışı makul maliyetle&gt; 100 W sağlayan kullanışlı cihazlardır. Birçok düzeneğinde, LDA daha fazla ya da daha az inci polarizasyon koruyan bir optik fiber içine yayane lazer ışığı. Yeterli Seop sürecini garanti etmek bu eliptik polarizasyon yüksek saflıkta dairesel polarizasyon dönüştürülmesi gerekir. Polarizasyon optik ana bileşenleri, Şekiller 1 ve 2 de gösterilmiştir ve sistem kurma ek film 1 &#39;de şematik olarak açıklanmaktadır. Dairesel ışık polarize için öncelikle güç yoğunluğu azaltmak için birincil ışın genişleme optikler (örneğin, bir fiber kolimatör) için fiber ucu takın. Işık daha sonra doğrusal polarize ışık üreten, polarize ışın ayırıcı küp geçer. Bu küpü çevirerek bir güç ölçer ile kalan kutuplaşma tercih ekseni belirleyebilirsiniz. Maksimum iletim küp hızlı ekseni ana ışık kutuplaşma ekseni ile hizalanır duruma tekabül eder. Yüksek tükenme katsayıları (100,000: 1 veya daha iyi) ile küpler polarizasyon bileşenlerinin iyi bir ayırma verim. Bu test edilebilirİlki olağanüstü ışının maksimum iletim için hizalanmış ise döndürülmüş bir analizör olarak ikinci bir demeti splitter küp kullanarak. Geçen ışığın polarizasyon doğrusal teyit edildikten sonra, 795 nm için tasarlanmış bir λ / 4 dalga plakası, dairesel bir polarizasyon içine doğrusal dönüştürmek için olağanüstü kiriş içine verilir. Bu amaç için, dalga plakasının hızlı eksen 45 ° ışın bölücü küp hızlı eksenine göre döndürülür. (Arzu edilirse, olağanüstü ışın ile lineer polarizasyon eksenine dik olan yansıyan sıradan kiriş dairesel polarizasyon benzer bir şekilde elde edilebilir.) Dairesel polarizasyon kalitesi dönme üzerine sabit bir transmisyon verim gereken ikinci bir ışın bölücü küp ile test edilebilir. İkincil ışın genişleme optikler (Galile teleskopla yapılandırmasında örneğin iki lens) sonra tamamen i ışın çapı artarbir fırın kutu içinde pompalama işlemi için cam hücre lluminate. Hücre içinde Rb, buhar ile lazer ışık emilimi kutu sonunda pompalama hücre arkasında bir iğne deliği vasıtasıyla takip edilir: bir kolimatör (hücre ayar pompalanması için bakınız Şekil 3, bir optik spektrometresi ile analiz edilmesi için zayıflatılmış bir kızılötesi ışın toplar ). Pompalama hücre dışında bir ısıtma mekanizması kısmi olarak hücre (Şekil 4a) içine oturan bir Rb damlacık buharlaşan ve bu nedenle lazer ışığı emme neden olur. Buharı yoğunluğu, ilgili PID kontrol cihazının sıcaklık ayar noktası ile ayarlanabilir. Yüksek sıcaklıklar (yaklaşık 190 ° C) xenon kutuplaşma oluşturmak için zaman sınırlı bir miktarda var kompakt kurulumları için iyidir. Xe&#39;nin, 2 N ve O içeren gaz karışımı lazer ışın yönüne ters pompalama hücre (Şekil 3) akar. Lazer ışını ile uyumlu bir dış manyetik alan bu th sağlare IR fotonları tek Rb geçiş pompalıyor. Elektron devletlerin Gevşeme hızlı ve &#39;yanlış&#39; kutuplaşma IR foton emisyonu önlemek için ışıksız olmalıdır. Burada, N 2 quench gaz olarak devreye giriyor. Diğer bir sürekli olarak lazer (Şekil 5) tarafından tüketilir iken Sonuç olarak, Rb sistem temel durum alt düzlemlere birinin bir çoğalmasını kurar. Rb atomları ile yakın temas halinde elde Xenon spin-spin etkileşimleri oluşur ve Elektron Spin polarizasyon flip-flop süreçlerinde Xe çekirdekleri üzerine transfer edilir. Pompalama hücre dışına akan gaz hyperpolarized. In vivo uygulamalarda, bununla birlikte, ilave eleme düşük sıcaklıkta (4b Şekil l&#39;e benzer şekilde) bağlı çıkış birkaç cm içinde boru duvarına kondensat gerektirir ki Rb buhar eser miktarda içerir alkali metal (soğuk tuzak yoluyla vs) in vitro experime oysaBu hyperpolarizer yapraklar gibi nts gaz ile güvenli bir şekilde uygulanabilir. Teflon tüp testi çözümleri NMR deneyleri gerçekleştirmek için cam aparatların girişi ile polarize çıkışı bağlanır. Kütle akış kontrolörleri NMR kurulum akan Xe miktarını ayarlamak için kullanılır. Onlar NMR puls sekansı komutları tetiklenir. Elde polarizasyon geliştirme kontrol edildikten sonra, çözelti, gaz durumu deneylerinde NMR / MRI kontrast ajanı olarak da kullanılabilir. Xe&#39;nin, bir su içinde belli bir çözünürlük (4.5 mM / atm) ve diğer çözücüler bulunmaktadır. Bu nedenle zaten bazı sıvıların dağılımını görüntüleyen bir kontrast ajan olarak kendi hizmet edebilir. Bununla birlikte, başka atıl gaz aracılığıyla moleküler özgü bilgileri elde etmek için bazı moleküllerin-NMR aktif çekirdekler bağlamak da mümkündür. Erimiş Xe için bir ana moleküler sağlayarak, Xe NMR sinyali moleküler özgüllük vermek mümkündür. Bu fırsatı sağlardizayn fonksiyonalitesi kontrast ajanları - biyosensör da adlandırılan - bu tür bir ana yapı biyomedikal ilgilenilen analit (Şekil 6) bağlanan bir hedef ünitesine bağlıdır. Biyosensör MR kontrast ajanları (&lt;100 uM) için düşük konsantrasyonlarda tespit edilmesi gerektiği zaman daha fazla duyarlılık artış gereklidir. Bu Kimyasal değişim doyma transferi (TSİ) ile elde edilebilir. Bu yöntem, kafesli Xe ve mıknatıslanma yok ve çözüm ücretsiz Xe arasında sinyal değişimi gözlemleyerek dolaylı biyosensör algılar. Hyperpolarized çekirdekler sürekli tespit havuzu üzerine bazı 10 ms, birçok 100 ila 1000 çekirdekler transferi bilgilerden sonra değiştirilir ve sinyal ca yükseltmek beri. 10 3 kat (film 2&#39;ye bakınız).

<table border="1"><tbody><tr><td> Reaktif Adı </td><td> Şirket </td><td> Katalog numarası </td><td> Yorumlar (isteğe bağlı) </td></tr><tr><td> Rb külçe </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> Lazer sistemi </td><td> QPC Lazerler / Lazer Operasyonlar </td><td> Brightlock 50 </td><td></td></tr><tr><td> Vakum sistemi </td><td> Pfeiffer </td><td> HiCube </td><td></td></tr><tr><td> Termokupllar </td><td> NewportOmega </td><td> SA2F-KI-3M </td><td></td></tr><tr><td> Silikon ısıtıcı </td><td> Newport Omega </td><td> FMA5514 </td><td></td></tr><tr><td> Basınç detektörler </td><td> Newport Omega </td><td> PR 33X-V-10 </td><td></td></tr><tr><td> Süreç metre </td><td> Newport Omega </td><td> INFCP-100B </td><td></td></tr><tr><td> Kütle akış kontrolörleri </td><td> Newport Omega </td><td> MFC </td><td></td></tr><tr><td> PID düzenleyiciler </td><td> Newport Omega </td><td> CN7800 </td><td></td></tr><tr><td> Kontrol Yazılımı </td><td> Newport Omega </td><td> DasyLab </td><td></td></tr><tr><td> Veri toplama </td><td> Newport Omega </td><td> Daqboard 3000 </td><td></td></tr><tr><td> Vakum sensörü </td><td> Oerlikon </td><td> TTR91 </td><td></td></tr><tr><td> Vakum denetleyici </td><td> Vacom </td><td> MVC-3 </td><td></td></tr><tr><td> Işın kolimatör </td><td> Thorlabs </td><td> F810SMA-780 </td><td></td></tr><tr><td> Polarize demeti splitter küpü </td><td> Thorlabs </td><td> GL15-B </td><td></td></tr><tr><td> λ / 4 dalga plakası </td><td> Thorlabs </td><td> WPQ10M-780 </td><td></td></tr><tr><td> Işın genişletme lensler </td><td> Thorlabs </td><td></td><td></td></tr><tr><td> Optik spektrometre </td><td> Ocean Optics </td><td> HR4000 </td><td></td></tr><tr><td> Fiber optik </td><td> Ocean Optics </td><td></td><td></td></tr><tr><td> Düşük basınç NMR tüpü </td><td> Wilmad </td><td> 513-7LPV-7 </td><td></td></tr><tr><td> 5mm NMR tüpü </td><td> Sigma-Aldrich </td><td> HX58.1 </td><td></td></tr><tr><td> Helmholtz bobinleri </td><td> Phywe </td><td> 06960-00 </td><td></td></tr><tr><td> Sigortalı silimca kılcal </td><td> Polymicro </td><td> TSG 250350 </td><td></td></tr></tbody></table>

hyperpolarized xenon for nmr and mri applications

~ 10 T bile güçlü dış manyetik alanların oda sıcaklığında 1 örnek sadece küçük saptanabilir net manyetizasyon üretir çünkü Nükleer manyetik rezonans (NMR) spektroskopisi ve görüntüleme (MRG) intrinsik düşük hassasiyeti muzdarip. Bu nedenle, en NMR ve MRG uygulamaları göreceli yüksek konsantrasyon (örneğin, su, biyolojik doku görüntüleme için) moleküllerin algılama güvenmek veya aşırı edinme süreleri gerektirir. Bu, birçok biyokimyasal ve tıbbi uygulamalar için NMR sinyalleri çok yararlı moleküler özgüllüğü yararlanabilmesi için yeteneğimizi sınırlar. Ancak, yeni yaklaşımlar son birkaç yıl içinde ortaya çıktı: tespit sıkma türlerin Manipülasyon öncesinde NMR / MRG mıknatıs içindeki algılama dramatik mıknatıslanma artırmak ve bu nedenle çok daha düşük konsantrasyonda 2 moleküllerin tespiti kılar. Burada, bir Xenon gaz karışımı (% 2-5 Xe,% 10 polarizasyon için bir yöntem mevcutN 2, bir ca ile kompakt kurulumunda O denge). 16000 kat sinyali iyileştirmek. Soygaz diğer bileşenler ayrılmış bile Modern çizgi-daralmış diyot lazerler verimli kutuplaşma 7 ve gaz karışımı hemen kullanıma izin verir. Seop cihaz açıklanmaktadır ve elde sıkma polarizasyon belirlenmesi yöntemi performans kontrol için gösterilmiştir. Hyperpolarized gaz gaz akışı görüntüleme ya da başka malzemeler ile 8,9 arayüzleri difüzyon çalışmaları da dahil olmak üzere, boş alan görüntüleme için de kullanılabilir. Ayrıca, Xe NMR sinyalinin moleküler ortamda 6 karşı son derece duyarlıdır. Bu geçici gaz 10,11 tuzak Fonksiyonlu moleküler bilgisayarlar ile sulu çözeltide çözündüğünde bir NMR / MRG kontrast ajan olarak kullanmak için bu seçeneği sağlar. Doğrudan algılama ve bu yapıların yüksek hassasiyet dolaylı olarak algılama spektroskopik ve görüntüleme hem modunda gösterilmiştir. &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

Optik dönüş değişimi (Seop) pompa vasıtasıyla hyperpolarized ksenon üretimi tarif edilmiştir. Bu yöntem Xe-129 nükleer spin kutuplaşma ~ 10000 kat büyütme verir ve nükleer manyetik rezonans spektroskopisi ve görüntüleme uygulamaları vardır. Gaz fazı ve çözelti durum deney örnekleri verilmiştir.

NMR ve MRG Uygulamaları için Hyperpolarized Xenon

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

Research

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Engineering

19.4K Görüntüleme.  Leibniz-Institut für Molekulare Pharmakologie. Optik dönüş değişimi (Seop) pompa vasıtasıyla hyperpolarized ksenon üretimi tarif edilmiştir. Bu yöntem Xe-129 nükleer spin kutuplaşma ~ 10000 kat büyütme verir ve nükleer manyetik rezonans spektroskopisi ve görüntüleme uygulamaları vardır. Gaz fazı ve çözelti durum deney örnekleri verilmiştir.

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.

Lityum Pil Uygulamaları için solid-state Greft Kopolimer Elektrolit

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

Mühendislik

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.

Hiperpolarize Manyetik Rezonans Ajanlar Araştırmaları bir Multi-bölmesi Dinamik Tek Enzim Phantom Kullanımı

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.

Türbülans Uygulamaları için üç boyutlu Parçacık Takip Akımları: Jet Akış Örneği

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.

Plazmonik ve Nanofotonik for Applications Nanopatch Antenlerin Kolloidal Sentezi

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.

Optik Rezonatör ve Lazer Uygulamalarında Polimer Mikrokürelerin Üretimi

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.

İmplantlar uygunluğu ve güvenlik açığı darbe sıralarının değerlendirmek için Metal tarafından neden MRI eserler değerlendirilmesi için iletişim kuralı implantlar

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.

Superhydrophobic Metal yüzeyler imalatı anti-buzlanma uygulamalar için

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.

Kavitasyon yüksek yoğunluklu arttırmak için Plazmonik altın nano tanecikleri üzerinden kontrol edilebilir çekirdekleşme ultrason uygulamaları odaklı

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.

En iyi duruma getirme, Test ve kırılan Hall iticileri teşhis

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.

Polimer Bazlı Nanokompozitlerin Dielektrik Özelliklerini Geliştirmek İçin Kaplin Maddesi Uygulaması

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