Questo lavoro è stato sostenuto da CPRIT concessione (RP140021-P5) e un premio Julia Jones Matthews Cancer Research Scholar CPRIT formazione alla ricerca (RP140106, CMW).

NOTA: (Phantom Design) Due 3 ml camere sono state ricavate da Ultem e dotati di tubi in PEEK (1,5875 millimetri OD e 0,762 millimetri ID) per l&#39;iniezione e di scarico. Le sezioni sono state poste in una provetta da centrifuga da 50 ml riempito con acqua (Figura 1). Per evitare vuoti di segnale creati da bolle, le camere e le linee sono stati pre riempiti con acqua deionizzata (DH 2 O). 1. Soluzione Preparazione <ol><li> Preparare 1 soluzione tampone L (81,3 mM Tris pH 7,6, 203,3 mM NaCl). Pesare 11.38 cristalli preimpostati g Trizma pH 7,6 e 11,88 g di NaCl e sciogliere in 1 L di dH 2 O. </li><li> Preparare 50 mM soluzione NADH. Pesare 17,8 mg di sale dipotassico β-nicotinammide adenina dinucleotide (NADH), ridotta e sciogliere in 280 ml di soluzione tampone che è stato preparato al punto uno. </li><li> Preparare 250 soluzione U / ml enzimatica. Pesare 78.75 unità di attività di lattato deidrogenasi (LDH) e sciogliere in 315 microlitri di buffer da sTep uno. </li><li> Preparare mix acido piruvico. Pesare 21,4 mg Ox063 trityl radicale e sciogliere in 1,26 g (~ 1 ml) [1- 13 C] acido piruvico. </li><li> Preparare supporti scioglimento (40 mM Tris pH 7,6, 40 mM NaOH, 0,27 mm e 50 mm EDTA NaCl). Pesare 5,96 g di cristalli Trizma preimpostati pH 7,6, 1,6 g di NaOH, 0,1 g di acido etilendiamminotetraacetico sale disodico diidrato (EDTA) e 2,9 g di NaCl e sciogliere in 1 L dH 2 O. </li><li> Preparare 01:10 soluzione Gadoteridolo (50 mm). Mescolare 1 ml di gadoteridolo in 9 ml di dH 2 O. Preparazione 8 M [13 C] urea. Pesare 1.465 5 urea [13 C] e sciogliere in 3 ml di dH 2 O. </li></ol> 2. Preparazione di hyperpolarized piruvato <ol><li> In una tazza di esempio per un sistema dinamico di polarizzazione nucleare (DNP), pipettare 0,3 ml di soluzione di Gadoteridolo e 13 mg (~ 10 microlitri) della soluzione di acido piruvico. </li><li> Brevemente mescolare questa miscela in tazza campione con la punta della pipetta. &lt;/ Li&gt; <li> Inserire campione nel sistema DNP. <ol><li> Assicurarsi che la porta al sistema di DNP è chiuso. Iniziare il processo di inserimento del campione facendo clic sul pulsante del campione inserto sulla console del sistema DNP. Sulla procedura guidata di esempio selezionare campione normale e premere Avanti. </li><li> Mantenere la coppa campioni verticale collocare delicatamente l&#39;asta di inserimento sopra la parte superiore della coppa campione. Quando richiesto, aprire il sistema DNP e inserire la coppa nell&#39;inserto a temperatura variabile (VTI) utilizzando l&#39;asta di inserimento. </li><li> Tirare lo stantuffo al termine della asta di inserimento del campione per rilasciare il campione nell&#39;indice a temperatura variabile. Rimuovere l&#39;asta di inserimento del campione dal sistema e fare clic sul pulsante Avanti sulla console del sistema DNP. </li></ol></li><li> Avviare la polarizzazione. <ol><li> Fare clic sul pulsante di avvio di polarizzazione sulla console del sistema DNP. Nel RINMR tipo di software .HYPERSENSENMR per lanciare la polarizzazione software di monitoraggio. Impostare costruire la configurazione a 1 e premere Invio. Quindi scegliere Genera solido up. </li><li> Impostare il percorso e il nome del file di salvataggio. Selezionare il profilo per il 13-C nella goccia scheda sulla console del sistema DNP verso il basso e fare clic su Avanti. Selezionare la casella di assaggiare durante l&#39;accumulo, impostare il tempo di campionamento di 300 sec e fare clic su Fine. </li></ol></li><li> Misurare 3,85 g (~ 4 ml) dei mezzi di dissoluzione sia in volume con una siringa da 5 ml o in peso utilizzando una scala. </li></ol> 3. Preparazione del Enzyme Fantasma <ol><li> Riempire una provetta con ~ 3 ml [13 C] soluzione di urea e posizionarlo nella provetta da centrifuga da 50 ml. Riempire la provetta da centrifuga da 50 ml con dH 2 O. </li><li> Pre-riempire le due camere enzimatici e le linee con dH 2 O iniettando ~ 3 ml di dH 2 O nelle linee d&#39;iniezione del fantoccio, avendo cura di svuotare eventuali bolle formate. </li><li> Posizionare il fantasma nel centro del magnete con facile accesso alle linee di iniezione. Assicurarsi che ci sia qualche contenitore per catturare il liquido che sfogare a t<html> egli linea di scarico. </li><li> Preparare la miscela di enzimi ad alta attività (17.14 mM NADH, 44.57 U / ml LDH). Mescolare 240 ml soluzione di NADH, soluzione LDH 125 ml e 335 ml di buffer e mantenere in una siringa da 3 ml che può essere collegato alla linea di iniezione. NOTA: Una volta unito con 500 ml di 40 mM di piruvato dal sistema DNP, il volume phantom finale sarà 1,2 ml con concentrazioni di 16,7 mM piruvato, 10 mM NADH e 26 U / L LDH in una soluzione tris tamponata a pH ~ 7.5. </li><li> Preparare la miscela attività enzimatica basso (17.14 mM NADH 26.79 U / ml LDH) Mescolare 240 ml soluzione di NADH, soluzione LDH 75 ml e 385 ml di buffer e conservare in un separato siringa da 3 ml che può essere collegato alla linea di iniezione. NOTA: Una volta unito con 500 ml di 40 mM di piruvato dal sistema DNP volume phantom finale sarà 1,2 ml con concentrazioni di 16,7 mM piruvato, 10 mM NADH e 15.625 U / L LDH in una soluzione tris tamponata a pH ~ 7,5 . </li></ol>jove_title &quot;&gt; 4. eseguire qualsiasi Quality Assurance (QA) e di posizionamento Scansioni <ol><li> posizionamento iniziale. <ol><li> Caricare una nuova scansione posizionamento FLASH in modalità di funzionamento [1 H] modalità Volume TX / RX. Cambiare impostare le dimensioni a 2: spettrometro Strumento di controllo -&gt; Modifica GS -&gt; Impostazione Dimensioni -&gt; 2. Premere GSP sul controllo Spectrometer e spostare fantasma fino al centro del magnete. Premere STOP quindi premere GOP sul controllo Spectrometer. </li></ol></li><li> Scan pilota. <ol><li> Caricare una nuova scansione posizionamento TriPiolt in modalità di funzionamento [1 H] modalità Volume TX / RX. Posizione Slice: Scan Control -&gt; fetta Tool-&gt; spostare fette (tenere premuto M chiave clic e trascinare, selezionare fetta di muoversi con il cursore pacchetto di fetta). </li><li> Wobble 1 H Coil: Strumento di controllo Spectrometer -&gt; Acq -&gt; Wobble. Tune and match 1 H serpentina dietro il magnete e premere STOP. Tenendo premuto il tasto Shift premere il semaforo sulla finestra di controllo di scansione. </li></ol></li></ol><pclass = &quot;jove_title&quot;&gt; 5. Setup radiale Echo Planar Spectral Imaging Scan <ol><li> Caricare un eco planare di imaging spettroscopico nuovo radiale (radEPSI) scansione in modalità di funzionamento [13 C] TX / RX modalità Volume. Posizione Slice: strumento sezione sul controllo di scansione e spostare fette (tenere M chiave clic e trascinare, selezionare fetta di muoversi con il cursore pacchetto di fetta). </li><li> Wobble 13 C Coil cliccando Spectrometer Strumento di controllo -&gt; Acq -&gt; Wobble. Impostare il guadagno del ricevitore per 1.000-2.000 sul Spectrometer. </li><li> Eseguire il controllo del sistema finale. Seconda della sequenza, osservare carbonio 13 segnale dalla camera di urea in un protocollo esploratore. NOTA: Questo assicura che il sistema sia configurato correttamente prima di iniziare il processo di dissoluzione irreversibile. </li></ol> 6. Eseguire Scioglimento <ol><li> Quando il piruvato ha raggiunto&gt; 90% di polarizzazione (~ 1 ora), le soluzioni e le fantasma sono pronti, e la scansione viene configurato clic sul pulsante Esegui dissoluzione sul sy DNParginare console. </li><li> Quando richiesto spostare il bastone di dissoluzione nella sua posizione di lavoro e iniettare mezzi di dissoluzione. Chiudere il sistema DNP e fare clic sul pulsante finito sulla console del sistema DNP. Spostare bastone dissoluzione nella posizione di riposo quando viene richiesto quindi fare clic su Fine. </li><li> Quando il sistema DNP batte il piruvato iperpolarizzato (~ 2 min dopo l&#39;inizio del riscaldamento) ritirare 500 microlitri della soluzione di piruvato in ciascuna delle siringhe soluzione di alta e bassa concentrazione dell&#39;enzima. Lentamente (~ 10 sec) iniettare ogni siringa in una linea di iniezione. NOTA: La scansione potrebbe essere stato avviato prima dell&#39;iniezione o in qualsiasi momento fino a dopo l&#39;iniezione 3 min a seconda del protocollo di scansione utilizzato. </li></ol> Processing 7. Immagine NOTA: Questo fantasma è stato progettato per essere utilizzato con molte strategie di imaging. Vedere Figura 2, come un esempio di come le immagini rad-EPSI stati trattati con Matlab. <ol><li> Caricare i dati grezzi dal file FID. Reshape i dati in base al numero di proiezioni, lettura punti, echi e considerazione per i dati memorizzati come coppie reali e immaginari. Separare i punti eco pari e dispari. </li><li> Fourier entrambi gli echi pari o dispari lungo le dimensioni eco. Visivamente individuare le bande di frequenza per piruvato e lattato. Per semplicità è stato utilizzato il valore assoluto dello spettro. </li><li> Separare ogni banda metabolita e trasformata di Fourier lungo la direzione di codifica di frequenza per produrre sinograms isolati per ogni metabolita. radon trasformazione inversa le sinograms separati per produrre l&#39;immagine di una lattato o piruvato. </li></ol>

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La pubblicazione di questo video-articolo è supportata da Bruker Corporation.

l&#39;imaging in tempo reale di metaboliti hyperpolarized ha molte sfide uniche per la progettazione sequenza, convalida e controllo qualità. La capacità di risolvere l&#39;eterogeneità spazio-temporale e spettrale offre un notevole potenziale clinico, ma preclude QA e validazione metodi associati con la RM convenzionale. sequenze di immagini complesse o algoritmi di ricostruzione possono avere dipendenze sottili che li rendono difficili da caratterizzare o convalidare al di fuori di questo esperimento di imaging. L&...

L&#39;impatto clinico della risonanza magnetica iperpolarizzato (MRI) di 13 composti C-marcati è criticamente dipendente dalla sua capacità di misurare i tassi di conversione chimica nel tempo reale spettroscopia di risonanza magnetica e spettroscopia di imaging 1-5. Durante lo sviluppo sequenza e la verifica, conversione chimica dinamica viene generalmente ottenuta attraverso in vivo o in vitro 6-9 che offrono un controllo limitato e riproducibilità. Per il test robusto e la garanzia della qualità, un sistema più controllato che conserva la conversione chimica endemica a questa misura sarebbe preferibile. Descriviamo un metodo per realizzare questa conversione in modo riproducibile utilizzando un singolo dinamica phantom enzima. La maggior parte degli studi con hyperpolarized 13 agenti C Focus on Imaging substrati hyperpolarized in un ambiente biologico funzionante. Questa è la scelta più ovvia se l&#39;obiettivo è quello di studiare biologicaAl trattate o determinare un potenziale di impatto sulla cura clinica. Tuttavia, se la caratterizzazione di qualche algoritmo di elaborazione del sistema di misura o di dati è desiderato, modelli biologici presentano numerosi inconvenienti quali intrinseca variabilità spaziale e temporale 10. Tuttavia, fantasmi statiche convenzionali hanno la conversione chimica che guida l&#39;interesse clinico primario in MRI di substrati hyperpolarized, e non possono essere utilizzati per caratterizzare rilevamento di tassi di conversione o altri parametri dinamici 11. Utilizzando un unico sistema enzimatico possiamo fornire conversione chimica controllabili e riproducibili, consentendo rigoroso esame delle strategie di imaging dinamico. Questo sistema è rivolto ai ricercatori che stanno sviluppando strategie di imaging per substrati hyperpolarized e desiderano caratterizzare le prestazioni per il confronto con approcci alternativi. Se le misurazioni statiche sono il punto finale desiderato quindi statico 13 C-etichettati metabolita fantasmi will bastare 11. Sull&#39;altra estremità se più caratterizzazione biologico complesso è fondamentale per il metodo (consegna, densità cellulare, ecc), allora saranno necessari modelli biologici effettive 12-14. Questo sistema è ideale per la valutazione delle strategie di imaging che mirano a fornire una misura quantitativa dei tassi di conversione chimica apparenti.

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		<tr height="21">
			<td height="21" style="height:21px;width:259px;">BioSpect 7T</td>
			<td style="width:147px;">Bruker</td>
			<td style="width:195px;">BioSpec 70/30 USR</td>
			<td style="width:445px;">7 Tesla Pre-Clinical MRI Scanner</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">HyperSense</td>
			<td style="width:147px;">Oxford Instruments</td>
			<td style="width:195px;">Hypersense DNP Polarizer</td>
			<td>Dynamic Nuclear Polarizer for MRI agents</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">1-13C-Pyrvic Acid</td>
			<td style="width:147px;">Sigma Aldrich</td>
			<td style="width:195px;">677175</td>
			<td>Carbon 13 labled neat pyruvic acid</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Trityl Radical</td>
			<td style="width:147px;">GE Healthcare</td>
			<td style="width:195px;">OX063</td>
			<td>Free radical used in Dynamic Nuclear Polarization</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">NaOH</td>
			<td style="width:147px;">Sigma Aldrich</td>
			<td style="width:195px;">S8045</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">EDTA</td>
			<td style="width:147px;">Sigma Aldrich</td>
			<td style="width:195px;">E6758</td>
			<td style="width:445px;">Ethylenediaminetetraacetic acid</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">LDH</td>
			<td style="width:147px;">Worthingthon</td>
			<td style="width:195px;">LS002755</td>
			<td>Lactate Dehydrogenase from rabbit muscle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">NADH</td>
			<td style="width:147px;">Sigma Aldrich</td>
			<td style="width:195px;">N4505</td>
			<td>&#946;-Nicotinamide adenine dinucleotide, reduced dipotassium salt</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Trizma</td>
			<td style="width:147px;">Sigma Aldrich</td>
			<td style="width:195px;">T7943</td>
			<td>Trizma&#174;&#160;Pre-set crystals</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">NaCl</td>
			<td style="width:147px;">Sigma Aldrich</td>
			<td style="width:195px;">S7653</td>
			<td></td>
		</tr>
	</tbody>
</table>

use of a multi-compartment dynamic single enzyme phantom for studies of hyperpolarized magnetic resonance agents

Imaging di substrati hyperpolarized di risonanza magnetica mostra una grande promessa per la valutazione clinica dei processi biochimici critici in tempo reale. A causa di vincoli fondamentali imposti dallo Stato iperpolarizzato, tecniche di imaging e di ricostruzione esotiche sono comunemente usati. è criticamente necessario un sistema pratico per la caratterizzazione delle dinamiche, metodi di imaging multi-spettrale. Tale sistema deve riproducibile ricapitolare le dinamiche chimici utili dei tessuti normali e patologici. Il substrato più ampiamente utilizzato fino ad oggi è hyperpolarized [1- 13 C] -pyruvate per la valutazione del metabolismo del cancro. Descriviamo un sistema phantom a base di enzimi che media la conversione del piruvato in lattato. La reazione viene iniziata mediante iniezione dell&#39;agente iperpolarizzato in più sezioni nell&#39;ambito del fantoccio, ciascuno dei quali contiene diverse concentrazioni di reagenti che controllano la velocità di reazione. Più compartimenti sono necessarie per garantire che imasequenze ging catturano fedelmente l&#39;eterogeneità spaziale e metaboliche del tessuto. Questo sistema sarà di aiuto allo sviluppo e la convalida di strategie di imaging avanzate, fornendo dinamiche chimiche che non sono disponibili da fantasmi convenzionali, così come il controllo e la riproducibilità ciò non è possibile in vivo.

immagini 2D Slice-selettivi sono state acquisite utilizzando una sequenza di istantanee radEPSI. immagini metabolita sono state ricostruite utilizzando di nuovo filtrato proiezione. Le immagini metabolita erano ben allineati con immagini di protoni, come visibile in figura 2. In questo sistema iperpolarizzato segnale lattato può essere generata solo dalla conversione enzimatica di piruvato iperpolarizzato. In figura 4, la camera inferiore, con concentra...

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

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 ...

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6.8K Views.  University of Texas M.D. Anderson Cancer Center. A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

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

Hyperpolarized Xenon for NMR and MRI Applications

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature 1. Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration 2.
Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization 7 and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method.
The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials 8,9. Moreover, the Xe NMR signal is extremely sensitive to its molecular environment 6. This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas 10,11. Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode.

The production of hyperpolarized xenon by means of spin exchange optical pumping (SEOP) is described. This method yields a ~10000-fold enhancement of the nuclear spin polarization of Xe-129 and has applications in nuclear magnetic resonance spectroscopy and imaging. Examples of gas phase and solution state experiments are given.

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 ...

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Analysis of Contact Interfaces for Single GaN Nanowire Devices

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit a strong degradation after annealing due to the occurrence of void formation at the contact/SiO2 interface. This void formation can cause cracking and delamination of the metal film, which can increase the resistance or lead to a complete failure of the NW device. In order to address issues associated with void formation, a technique was developed that removes Ni/Au contact metal films from the substrates to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN NW devices. This procedure determines the degree of adhesion of the contact films to the substrate and NWs and allows for the characterization of the morphology and composition of the contact interface with the substrate and nanowires. This technique is also useful for assessing the amount of residual contamination that remains from the NW suspension and from photolithographic processes on the NW-SiO2 surface prior to metal deposition. The detailed steps of this procedure are presented for the removal of annealed Ni/Au contacts to Mg-doped GaN NWs on a SiO2 substrate.

A technique was developed that removes Ni/Au contact metal films from their substrate to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN nanowire devices.

Analisi di contatto Interfacce semplici dispositivi GaN nanowire

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit  a strong degradation after annealing due to the  occurrence of void formation at the ...

Scalable Nanohelices for Predictive Studies and Enhanced 3D Visualization

Spring-like materials are ubiquitous in nature and of interest in nanotechnology for energy harvesting, hydrogen storage, and biological sensing applications.&#160; For predictive simulations, it has become increasingly important to be able to model the structure of nanohelices accurately.&#160; To study the effect of local structure on the properties of these complex geometries one must develop realistic models.&#160; To date, software packages are rather limited in creating atomistic helical models.&#160; This work focuses on producing atomistic models of silica glass (SiO2) nanoribbons and nanosprings for molecular dynamics (MD) simulations. Using an MD model of &#8220;bulk&#8221; silica glass, two computational procedures to precisely create the shape of nanoribbons and nanosprings are presented.&#160; The first method employs the AWK programming language and open-source software to effectively carve various shapes of silica nanoribbons from the initial bulk model, using desired dimensions and parametric equations to define a helix.&#160; With this method, accurate atomistic silica nanoribbons can be generated for a range of pitch values and dimensions.&#160; The second method involves a more robust code which allows flexibility in modeling nanohelical structures.&#160; This approach utilizes a C++ code particularly written to implement pre-screening methods as well as the mathematical equations for a helix, resulting in greater precision and efficiency when creating nanospring models.&#160; Using these codes, well-defined and scalable nanoribbons and nanosprings suited for atomistic simulations can be effectively created.&#160; An added value in both open-source codes is that they can be adapted to reproduce different helical structures, independent of material.&#160; In addition, a MATLAB graphical user interface (GUI) is used to enhance learning through visualization and interaction for a general user with the atomistic helical structures.&#160; One application of these methods is the recent study of nanohelices via MD simulations for mechanical energy harvesting purposes.

Accurate modeling of nanohelical structures is important for predictive simulation studies leading to novel nanotechnology applications.&#160; Currently, software packages and codes are limited in creating atomistic helical models.&#160; We present two procedures designed to create atomistic nanohelical models for simulations, and a graphical interface to enhance research through visualization.

Nanohelices scalabili per predittivi Studi e migliorata visualizzazione 3D

Spring-like materials are ubiquitous in nature and of interest in nanotechnology for energy harvesting, hydrogen storage, and biological sensing ...

High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe.

Nuclear magnetic resonance is one of the most important spectroscopic tools. Here, the development of a new approach under high pressure, currently up to 10.1 GPa, is presented. This opens a new window into condensed matter physics and chemistry, where high-pressure research is of great importance.

Ad alta sensibilità la Risonanza Magnetica Nucleare a Giga-Pascal Pressioni: Un nuovo strumento per Probing proprietà elettroniche e chimiche della Materia Condensata in condizioni estreme

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their ...

A Method for Studying the Temperature Dependence of Dynamic Fracture and Fragmentation

The dynamic fracture of a body is a late-stage phenomenon typically studied under simplified conditions, in which a sample is deformed under uniform stress and strain rate. This can be produced by evenly loading the inner surface of a cylinder. Due to the axial symmetry, as the cylinder expands the wall is placed into a tensile hoop stress that is uniform around the circumference. While there are various techniques to generate this expansion such as explosives, electromagnetic drive, and existing gas gun techniques they are all limited in the fact that the sample cylinder must be at room temperature. We present a new method using a gas gun that facilitates experiments on cylinders from 150 K to 800 K with a consistent, repeatable loading. These highly diagnosed experiments are used to examine the effect of temperature on the fracture mechanisms responsible for failure, and their resulting influence on fragmentation statistics. The experimental geometry employs a steel ogive located inside the target cylinder, with the tip located about halfway in. A single stage light gas gun is then used to launch a polycarbonate projectile into the cylinder at 1,000 m/sec-1. The projectile impacts and flows around the rigid ogive, driving the sample cylinder from the inside. The use of a non-deforming ogive insert allows us to install temperature control hardware inside the rear of the cylinder. Liquid nitrogen (LN2) is used for cooling and a resistive high current load for heating. Multiple channels of upshifted photon Doppler velocimetry (PDV) track the expansion velocity along the cylinder enabling direct comparison to computer simulations, while High speed imaging is used to measure the strain to failure. The recovered cylinder fragments are also subject to optical and electron microscopy to ascertain the failure mechanism.

Fracture and fragmentation are late stage phenomena in dynamic loading scenarios and are typically studied using explosives. We present a technique for driving expansion using a gas gun which uniquely enables control of both loading rate and sample temperature.

Un metodo per studiare la dipendenza dalla temperatura della dinamica Frattura e frammentazione

The dynamic fracture of a body is a late-stage phenomenon typically studied under simplified conditions, in which a sample is deformed under uniform ...

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors1. As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique.

Shear stress investigations on an oil-water emulsion system result in drop breakup over the experimental time. To count drop sizes in pumping processes, the suitability of inline endoscopy was successfully demonstrated in this protocol.

Un metodo conveniente e affidabile per prevedere lo stress meccanico in monouso e pompe standard

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping ...

Design and Use of a Full Flow Sampling System (FFS) for the Quantification of Methane Emissions

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas industry faces continued scrutiny for methane emissions from across the supply chain, due to methane&#39;s relatively high global warming potential (25-84x that of carbon dioxide, according to the Energy Information Administration). Currently, a variety of techniques of varied uncertainties exists to measure or estimate methane emissions from components or facilities. Currently, only one commercial system is available for quantification of component level emissions and recent reports have highlighted its weaknesses.
In order to improve accuracy and increase measurement flexibility, we have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases based on transportation emissions measurement principles. The FFS is a modular system that consists of an explosive-proof blower(s), mass airflow sensor(s) (MAF), thermocouple, sample probe, constant volume sampling pump, laser based greenhouse gas sensor, data acquisition device, and analysis software. Dependent upon the blower and hose configuration employed, the current FFS is able to achieve a flow rate ranging from 40 to 1,500 standard cubic feet per minute (SCFM). Utilization of laser-based sensors mitigates interference from higher hydrocarbons (C2+). Co-measurement of water vapor allows for humidity correction. The system is portable, with multiple configurations for a variety of applications ranging from being carried by a person to being mounted in a hand drawn cart, on-road vehicle bed, or from the bed of utility terrain vehicles (UTVs). The FFS is able to quantify methane emission rates with a relative uncertainty of &#177; 4.4%. The FFS has proven, real world operation for the quantification of methane emissions occurring in conventional and remote facilities.

Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

We have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases from across the natural gas supply chain.

Progettazione e l&#39;uso di un sistema di campionamento a flusso pieno (FFS) per la quantificazione delle emissioni di metano

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas ...

A Modular Microfluidic Technology for Systematic Studies of Colloidal Semiconductor Nanocrystals

Colloidal semiconductor nanocrystals, known as quantum dots (QDs), are a rapidly growing class of materials in commercial electronics, such as light emitting diodes (LEDs) and photovoltaics (PVs). Among this material group, inorganic/organic perovskites have demonstrated significant improvement and potential towards high-efficiency, low-cost PV fabrication due to their high charge carrier mobilities and lifetimes. Despite the opportunities for perovskite QDs in large-scale PV and LED applications, the lack of fundamental and comprehensive understanding of their growth pathways has inhibited their adaptation within continuous nanomanufacturing strategies. Traditional flask-based screening approaches are generally expensive, labor-intensive, and imprecise for effectively characterizing the broad parameter space and synthesis variety relevant to colloidal QD reactions. In this work, a fully autonomous microfluidic platform is developed to systematically study the large parameter space associated with the colloidal synthesis of nanocrystals in a continuous flow format. Through the application of a novel translating three-port flow cell and modular reactor extension units, the system may rapidly collect fluorescence and absorption spectra across reactor lengths ranging 3 - 196 cm. The adjustable reactor length not only decouples the residence time from the velocity-dependent mass transfer, it also substantially improves the sampling rates and chemical consumption due to the characterization of 40 unique spectra within a single equilibrated system. Sample rates may reach up to 30,000 unique spectra per day, and the conditions cover 4 orders of magnitude in residence times ranging 100 ms - 17 min. Further applications of this system would substantially improve the rate and precision of the material discovery and screening in future studies. Detailed within this report are the system materials and assembly protocols with a general description of the automated sampling software and offline data processing.

Detailed herein are the operation and assembly protocols of a modular microfluidic screening platform for the systematic characterization of colloidal semiconductor nanocrystal syntheses. Through fully adjustable system arrangements, highly efficient spectra collection may be carried out across 4 orders of magnitude reaction time scales within a mass transfer-controlled sampling space.

Un modulare tecnologia microfluidica per studi sistematici di nanocristalli semiconduttori colloidali

Colloidal semiconductor nanocrystals, known as quantum dots (QDs), are a rapidly growing class of materials in commercial electronics, such as light ...

Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared on transparent membranes which are very fragile and difficult to manipulate. We present processes for the fabrication of samples with magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for Lorentz transmission electron microscopy and magnetic transmission x-ray microscopy studies. The samples are prepared on silicon nitride membranes and the fabrication consists of a spin coating, UV and electron-beam lithography, the chemical development of the resist, and the evaporation of the magnetic material followed by a lift-off process forming the final magnetic structures. The samples for the Lorentz transmission electron microscopy consist of magnetic nanodiscs prepared in a single lithography step. The samples for the magnetic x-ray transmission microscopy are used for time-resolved magnetization dynamic experiments, and magnetic nanodiscs are placed on a waveguide which is used for the generation of repeatable magnetic field pulses by passing an electric current through the waveguide. The waveguide is created in an extra lithography step.

A protocol for the fabrication of magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for transmission electron microscopy (TEM) and magnetic transmission x-ray microscopy (MTXM) studies is presented.

Fabbricazione di nanostrutture magnetiche sulle membrane di nitruro di silicio per studi di vortice magnetico utilizzando tecniche di microscopia di trasmissione

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared ...

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate plasma to high speed; they have considerable potential for future space applications with the significant advantages of high specific impulse and thrust density. In this paper, we present a series of protocols for designing and manufacturing a 100 kW class of AF-MPD thruster with water-cooling structures, a 130 V maximum discharge voltage, a 800 A maximum discharge current, and a 0.25 T maximum strength of magnetic field. A hollow tantalum tungsten cathode acts as the only propellant inlet to inhibit the radial discharge, and it is positioned axially at the rear of the anode in order to relieve anode starvation. A cylindrical divergent copper anode is employed to decrease anode power deposition, where the length has been reduced to decrease the wall-plasma connecting area. Experiments utilized a vacuum system that can achieve a working vacuum of 0.01 Pa for a total propellant mass flow rate lower than 40 mg/s and a target thrust stand. The thruster tests were carried out to measure the effects of the working parameters such as propellant flow rates, the discharge current, and the strength of applied magnetic field on the performance and to allow appropriate analysis. The thruster could be operated continuously for significant periods of time with little erosion on the hollow cathode surface. The maximum power of the thruster is 100 kW, and the performance of this water-cooled configuration is comparable with that of thrusters reported in the literature.

The goal of this protocol is to introduce the design of a 100 kW class applied-field magnetoplasmadynamic thruster and relevant experimental methods.

Un 100 KW classe campo applicato Magnetoplasmadynamic Thruster

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate ...

L'uso di un multi-comparto dinamico singolo enzima Phantom per gli Studi di hyperpolarized Risonanza Magnetica Agents

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