Questo lavoro è stato supportato da una BU / CIMIT Fellowship Applicata Sanità Ingegneria Predoctoral, una National Science Foundation ampliare la partecipazione di Ricerca in Ingegneria Iniziazione di Grant (Brige), e il National Institutes of Health (R21EB0094930).

1. Preparazione della fase-shift nanoemulsione (PSNE) <ol><li> Sciogliere 11 mg e 1,68 mg DPPC DSPE-PEG2000 in cloroformio </li><li> Si evapora il solvente organico per formare un film secco lipide in un pallone di vetro a fondo rotondo </li><li> Dessicate il film lipidico durante la notte </li><li> Reidratare il film lipidico con 5,5 ml di tampone fosfato salino (PBS) </li><li> Soluzione di calore in un bagno di acqua a 45 ° C fino a quando si scioglie film lipidico, vortex periodicamente </li><li> Trasferire la soluzione lipidica in 7 ml Fiala </li><li> Sonicare soluzione lipidica per 2 min a 20% dell&#39;ampiezza </li><li> Dividere la soluzione in due flaconcini da 2,5 ml (scartare restante 0,5 ml) </li><li> Aggiungere 2,5 ml di soluzione salina in ogni fiala </li><li> Posizionare ciascun flacone con un 0 ° C bagno di acqua ghiacciata </li><li> Aggiungere 50 microlitri DDFP ad ogni flacone </li><li> Sonicare ogni flacone nel bagno di acqua ghiacciata utilizzando le seguenti impostazioni: 25% di ampiezza, modalità pulsata (10 sec a 50 sec spento), 60 secondi sul tempo totale </li><li> Transfer soluzioni PSNE a 20 fiale da scintillazione ml </li><li> Aggiungere 5 ml di soluzione salina in ogni fiala, con conseguente in 10 ml di volume finale </li><li> Montare indicazioni seguenti estrusione forniti dal produttore <ol><li> Lavare ogni parte con acqua deionizzata </li><li> Posizionare il disco di supporto in acciaio inox al centro della base di supporto filtro </li><li> Posizionare la maglia di acciaio inossidabile sulla parte superiore del disco di sostegno dell&#39;acciaio inossidabile </li><li> Con una pinzetta, posizionare una membrana di scarico estrusore disco (su lato lucido) sulla rete di acciaio inossidabile </li><li> Con una pinzetta, posizionare il filtro estrusore (il lato lucido) sulla membrana disco di scarico </li><li> Posizionare con cura il piccolo O-ring sul filtro e posizionare il thermobarrel e top estrusore al di sopra della base d&#39;appoggio </li><li> Serrare parzialmente ogni ala-primo dado, quindi serrare a fondo le ali-dadi a mano, in modo alterno </li><li> Collegare l&#39;estrusore auna linea di gas azoto </li><li> Per caricare il, estrusore pipetta da 10 ml di acqua deionizzata alla porta di esempio, chiudere l&#39;apertura, e serrare la valvola di sfiato </li><li> Aprire lentamente la linea di gas azoto per aumentare la pressione, costringendo il campione attraverso le membrane, e raccogliere il campione dal tubo di uscita </li><li> Dopo l&#39;uso, smontaggio in ordine inverso, sciacquare le parti dell&#39;estrusore con acqua deionizzata, e gettare il filtro a membrana e scarico disco membrana </li></ol></li><li> Per 100 nm goccioline solo, pre-condizione PSNE per estrusione di 10 volte con filtro a 200 nm </li><li> Estrusione PSNE 16 volte in 100 nm o 200 nm di filtro per ottenere una distribuzione ristretta dimensione </li></ol> 2. Preparazione di Hydrogel poliacrilammide contenente PSNE <ol><li> Preparare una soluzione al 24% di BSA diluendo 1,2 g BSA polvere in 5 ml di acqua deionizzata </li><li> Preparare la soluzione APS 10% diluito 0,1 g di polvere in 1 ml APS deionizzata water </li><li> Nel seguente ordine, miscelare 2,1 ml di soluzione di acrilammide, 1,2 ml di tampone Tris, 0,1 ml APS 10%, 4,5 ml di soluzione al 24% di BSA e 3,6 ml di acqua deionizzata in camera di plastica </li><li> Riscaldare a 40 ° C e posto sotto vuoto per 1 ora </li><li> Aggiungere 480 ml di PSNE e mescolare bene agitando con delicatezza la camera di plastica. </li><li> Aggiungere 12 microlitri TEMED e posizionare la camera in un bagno di acqua 12 ° C per 2 ore </li></ol> 3. Risultati rappresentativi Un schematico della configurazione per esperimenti ultrasuoni con tessuti che imitano fantasmi idrogel è mostrato in Figura 1. Questo protocollo risulta in lipidi rivestite goccioline perfluorocarburiche con una distribuzione di dimensione ristretta che sono stabili in soluzione per almeno una settimana. La distribuzione della dimensione misurata con light scattering dinamico (Particle Analyzer 90Plus Size, Brookhaven Instruments, Holtsville, NY) è mostrato in Figura 2 per PSNE estrusi con 100 e 200nm filtri. Il diametro PSNE efficace nel tempo, misurato utilizzando dispersione dinamica della luce, è riportata nella Tabella 1, dimostrando che PSNE sono stabili per almeno una settimana. B-mode immagini di PSNE prima e dopo vaporizzazione in un idrogel di poliacrilamide sono mostrati in Figura 3. Inoltre, una lesione formata da 15 sec di HIFU-mediata riscaldamento in un idrogel di poliacrilamide contenente albumina e PSNE è mostrato in Figura 4. La forma asimmetrica della lesione è il risultato del riscaldamento prefocal che si verifica a causa della presenza della nube bolla nel percorso ultrasuoni. È importante notare che il riscaldamento prefocal e formazione di lesione a causa dispersione da bolle può essere minimizzata riducendo la potenza acustica trasmessa. <img src="/files/ftp_upload/4308/4308fig1.jpg" alt="Figura 1"/> Figura 1. Schema del setup sperimentale per ultrasuoni esperimenti con tessuto-mimIcking idrogel. <img src="/files/ftp_upload/4308/4308fig2.jpg" alt="Figura 2"/> Figura 2. Dimensione distribuzione di PSNE estruso attraverso 100 nm o 200 nm filtri, misurata con Dynamic Light Scattering. Le unità degli assi delle ordinate sono basati sull&#39;intensità della luce diffusa dalle particelle di una certa dimensione relativa alla intensità totale della luce diffusa dal campione. <img src="/files/ftp_upload/4308/4308fig3.jpg" alt="Figura 3"/> Figura 3. Immagini B-mode (a) prima e (b) dopo la vaporizzazione PSNE in un idrogel di poliacrilamide. La freccia indica la regione focale dove è formata una nube bolla per vaporizzazione PSNE. <img src="/files/ftp_upload/4308/4308fig4.jpg" alt="Figura 4"/> Immagini Figura 4. Del polyacrylamide idrogel contenente albumina e PSNE (a) prima e (b) dopo la vaporizzazione e la sonicazione con HIFU, dimostrando formazione di lesione a seguito di ultrasuoni indotta riscaldamento. La frequenza centrale degli ultrasuoni è stata del 3,3 MHz. Il segnale ad ultrasuoni consisteva in un ciclo iniziale di 30, 6,4 W impulsi per vaporizzare PSNE, immediatamente seguito da 15 secondi di ultrasuoni continuo a 0,77 W. <table border="1"><tbody><tr><td rowspan="2"> Giorni dopo estrusione </td><td colspan="2"> Estruso con filtro a 200 nm </td><td colspan="2"> Estruso con filtro 100 nm </td></tr><tr><td> Media Dia. (Nm) </td><td> Std. Dev. (Nm) </td><td> Media Dia. (Nm) </td><td> Std. Dev. (Nm) </td></tr><tr><td> 1 </td><td> 182,9 </td><td> 4,9 </td><td> 118,0 </td><td> 0,9 </td></tr><tr><td> 7 </td> &lt;td&gt; 177,7 </td><td> 2,5 </td><td> 124,8 </td><td> 3,1 </td></tr></tbody></table> Tabella 1. Diametro medio e la deviazione standard di PSNE a uno e sette giorni dopo l&#39;estrusione con 100 nm e 200 nm filtri.

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Nessun conflitto di interessi dichiarati.

Ultrasuoni focalizzati ad alta intensità (HIFU) è usato clinicamente per l&#39;ablazione termica tumori. 1 Per migliorare riscaldamento localizzato e migliorare ablazione termica nei tumori, lipidi rivestite goccioline perfluorocarburiche sono stati sviluppati che possono essere vaporizzato da HIFU. La vascolarizzazione in molti tumori è anormalmente perde a causa della loro rapida crescita. 2 Così, nanoparticelle sono in grado di penetrare le fenestrazioni e passivamente accumulano all&#39;int...

<table border="1"><tbody><tr><td> Nome comune </td><td> Fabbricante </td><td> Cat. Numero </td><td> Nome e Cognome / Descrizione </td></tr><tr><td> DPPC </td><td> Lipidi Avanti, Alabaster, AL, Stati Uniti d&#39;America </td><td> 850355P </td><td> 1,2-dipalmitoil-sn-glycero-3-phosphocholine </td></tr><tr><td> DSPE-PEG2000 </td><td> Lipidi Avanti, Alabaster, AL, Stati Uniti d&#39;America </td><td> 880120P </td><td> 1,2-distearoil-sn-glycero-3-phosphoethanolamine-N-[metossi (polietilene glicole) -2000] (sale di ammonio) </td></tr><tr><td> DDFP </td><td> Fluoromed, Round Rock, TX, Stati Uniti d&#39;America </td><td> CAS: 138495-42-8 </td><td> Dodecafluoropentano (C 5 F 12) </td></tr><tr><td> PBS </td><td> Sigma-Aldrich, St. Louis, MO, Stati Uniti d&#39;America </td><td> P2194 </td><td> PBS </td></tr><tr><td> Cloroformio </td><td> Sigma-Aldrich, St. Louis, MO, Stati Uniti d&#39;America </td><td> 372978 </td><td> Cloroformio </td></tr><tr><td> Acrilamide </td><td> Sigma-Aldrich, St. Louis, MO, Stati Uniti d&#39;America </td><td> A9926 </td><td> 40% 19:01 acrilammide / bis-acrilamide </td></tr><tr><td> Tampone Tris </td><td> Sigma-Aldrich, St. Louis, MO, Stati Uniti d&#39;America </td><td> T2694 </td><td> 1M, pH 8, cloridrato trizma e trizma di base </td></tr><tr><td> BSA </td><td> Sigma-Aldrich, St. Louis, MO, Stati Uniti d&#39;America </td><td> A3059 </td><td> Albumina di siero bovino </td></tr><tr><td> APS </td><td> Sigma-Aldrich, St. Louis, MO, Stati Uniti d&#39;America </td><td> A3678 </td><td> Ammonio persolfato soluzione </td></tr><tr><td> TEMED </td><td> Sigma-Aldrich, St. Louis, MO, Stati Uniti d&#39;America </td><td> 87689 </td><td> N, N, N &#39;, N&#39;-tetrametiletilendiammina </td></tr><tr><td></td><td></td><td></td><td> Attrezzatura </td></tr><tr><td> Sonicator (3 punta mm) </td&gt; <td> Sonics &amp; Materials, Inc., Newtown, CT, Stati Uniti d&#39;America </td><td> Vibra-Cell </td><td></td></tr><tr><td> Bagnomaria </td><td> Thermo Fisher Scientific, Waltham, MA, Stati Uniti d&#39;America </td><td> Neslab EX-7 </td><td></td></tr><tr><td> Estrusore </td><td> Lipidi del Nord, Burnaby, BC, Canada </td><td> Lipex </td><td></td></tr><tr><td> Estrusori Filtri </td><td> Whatman, Piscataway, NJ, USA </td><td> Nuclepore # 110605 e # 110606 </td><td></td></tr><tr><td> Estrusore di scarico del disco </td><td> Sterlitech Corporation, Kent, WA, Stati Uniti d&#39;America </td><td> # PETEDD25100 </td><td></td></tr><tr><td> Camera di plastica </td><td> US Plastic Corporation, Lima, OH, Stati Uniti d&#39;America </td><td> # 55288, 1 3/16 &quot;x 1 3/16&quot; x 2 7/16 &quot; </td><td></td></tr></tbody></table>

synthesis of phase-shift nanoemulsions with narrow size distributions for acoustic droplet vaporization and bubble-enhanced ultrasound-mediated ablation

Ultrasuoni focalizzati ad alta intensità (HIFU) è usato in clinica per l&#39;ablazione termica dei tumori. Per migliorare riscaldamento localizzato e migliorare ablazione termica nei tumori, lipidi rivestite goccioline perfluorocarburiche sono stati sviluppati che possono essere vaporizzato da HIFU. La vascolarizzazione in molti tumori è anormalmente perde a causa della loro rapida crescita, e nanoparticelle sono in grado di penetrare le fenestrazioni e passivamente accumulano all&#39;interno del tumore. Pertanto, controllando la dimensione delle goccioline può migliorare accumulo all&#39;interno del tumore. In questa relazione, la preparazione di gocce stabili in un sfasamento nanoemulsione (PSNE) con una distribuzione granulometrica ristretta viene descritto. PSNE stati sintetizzati da sonicating una soluzione lipidica in presenza di perfluorocarburo liquido. Una distribuzione dimensionale ristretta è stato ottenuto estrudendo i tempi PSNE multipli utilizzando filtri con pori di 100 o 200 nm. La distribuzione delle dimensioni è stata misurata in un periodo di 7 giorni con Dynamic Light Scattering. Polyacidrogel rylamide contenenti PSNE sono stati preparati per esperimenti in vitro. Goccioline PSNE nei idrogel sono stati vaporizzati con gli ultrasuoni e le bolle risultano migliorate riscaldamento localizzato. Vaporizzato PSNE permette un riscaldamento più rapido e riduce anche l&#39;intensità ultrasuoni necessari per l&#39;ablazione termica. Così, PSNE dovrebbe migliorare ablazione termica nei tumori, migliorando potenzialmente risultati terapeutici di HIFU-mediate trattamenti di ablazione termica.

Watch this Scientific Journal Video about Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation at Jo

Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

Phase-shift nanoemulsioni (PSNE) può essere vaporizzato con ultrasuoni focalizzati ad alta intensità per migliorare il riscaldamento localizzato e migliorare la termoablazione nei tumori. In questa relazione, la preparazione di PSNE stabile con una distribuzione di dimensione stretta è descritto. Inoltre, l&#39;impatto di PSNE vaporizzato su ultrasuoni-mediata ablazione è in tessuti che imitano fantasmi.

Sintesi di fase-shift nanoemulsioni con distribuzioni di dimensioni strette per vaporizzazione Droplet acustico e Bubble-enhanced Ultrasound-mediata Ablazione

High-intensity  focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To  enhance localized heating and improve thermal ablation in ...

synthesis-phase-shift-nanoemulsions-with-narrow-size-distributions

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11.0K Views.  Boston University. Phase-shift nanoemulsioni (PSNE) può essere vaporizzato con ultrasuoni focalizzati ad alta intensità per migliorare il riscaldamento localizzato e migliorare la termoablazione nei tumori. In questa relazione, la preparazione di PSNE stabile con una distribuzione di dimensione stretta è descritto. Inoltre, l'impatto di PSNE vaporizzato su ultrasuoni-mediata ablazione è in tessuti che imitano fantasmi.

Video: Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do so is highly important in view of a number of applications in functional soft matter including electronics, biomedical engineering, and sensors. In the past, successful strategies to control the size and shape of supramolecular polymers typically focused on the use of templates2,3, end cappers4 or selective solvent techniques5. 
Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing electrostatic repulsive interactions on the hydrophilic rim and attractive non-covalent forces within the hydrophobic core of the polymerizing building block, we manage to create small and discrete spherical objects6,7. Increasing the salt concentration to screen the charges induces a sphere-to-rod transition. Intriguingly, this transition is expressed in an increase of cooperativity in the temperature-dependent self-assembly mechanism, and more stable aggregates are obtained. 
For our study we select a benzene-1,3,5-tricarboxamide (BTA) core connected to a hydrophilic metal chelate via a hydrophobic, fluorinated L-phenylalanine based spacer (Scheme 1). The metal chelate selected is a Gd(III)-DTPA complex that contains two overall remaining charges per complex and necessarily two counter ions. The one-dimensional growth of the aggregate is directed by &pi;-&pi; stacking and intermolecular hydrogen bonding. However, the electrostatic, repulsive forces that arise from the charges on the Gd(III)-DTPA complex start limiting the one-dimensional growth of the BTA-based discotic once a certain size is reached. At millimolar concentrations the formed aggregate has a spherical shape and a diameter of around 5 nm as inferred from 1H-NMR spectroscopy, small angle X-ray scattering, and cryogenic transmission electron microscopy (cryo-TEM). The strength of the electrostatic repulsive interactions between molecules can be reduced by increasing the salt concentration of the buffered solutions. This screening of the charges induces a transition from spherical aggregates into elongated rods with a length &gt; 25 nm. Cryo-TEM allows to visualise the changes in shape and size. In addition, CD spectroscopy permits to derive the mechanistic details of the self-assembly processes before and after the addition of salt. Importantly, the cooperativity -a key feature that dictates the physical properties of the produced supramolecular polymers- increases dramatically upon screening the electrostatic interactions. This increase in cooperativity results in a significant increase in the molecular weight of the formed supramolecular polymers in water.

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

Controllo della dimensione, forma e stabilità dei polimeri supramolecolari in acqua

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do ...

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Synthesis and Operation of Fluorescent-core Microcavities for Refractometric Sensing

This paper discusses fluorescent core microcavity-based sensors that can operate in a microfluidic analysis setup. These structures are based on the formation of a fluorescent quantum-dot (QD) coating on the channel surface of a conventional microcapillary. Silicon QDs are especially attractive for this application, owing in part to their negligible toxicity compared to the II-VI and II-VI compound QDs, which are legislatively controlled substances in many countries. While the ensemble emission spectrum is broad and featureless, an Si-QD film on the channel wall of a capillary features a set of sharp, narrow peaks in the fluorescence spectrum, corresponding to the electromagnetic resonances for light trapped within the film. The peak wavelength of these resonances is sensitive to the external medium, thus permitting the device to function as a refractometric sensor in which the QDs never come into physical contact with the analyte. The experimental methods associated with the fabrication of the fluorescent-core microcapillaries are discussed in detail, as well as the analysis methods. Finally, a comparison is made between these structures and the more widely investigated liquid-core optical ring resonators, in terms of microfluidic sensing capabilities.

Fluorescent-core microcavity sensors employ a high-index quantum-dot coating in the channel of silica microcapillaries. Changes in the refractive index of fluids pumped into the capillary channel cause shifts in the microcavity fluorescence spectrum that can be used to analyze the channel medium.

Sintesi e funzionamento del fluorescente-core microcavità per il Rilevamento rifrattometrico

This paper discusses  fluorescent core microcavity-based sensors that can operate in a microfluidic  analysis setup. These structures are based on the ...

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.

The Vaporization of a Sacrificial Component (VaSC) process is used to fabricate microvascular structures. This procedure uses sacrificial poly(lactic) acid fibers to form hollow microchannels with precise 3D geometric positioning provided by laser micromachined guide plates.

Processo di creazione di microstrutture tridimensionali mediante vaporizzazione di un componente sacrificale

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we present the fabrication protocol for a multilayered SAW acoustic counterflow device. The device is fabricated starting from a lithium niobate (LN) substrate onto which two interdigital transducers (IDTs) and appropriate markers are patterned. A polydimethylsiloxane (PDMS) channel cast on an SU8 master mold is finally bonded on the patterned substrate. Following the fabrication procedure, we show the techniques that allow the characterization and operation of the acoustic counterflow device in order to pump fluids through the PDMS channel grid. We finally present the procedure to visualize liquid flow in the channels. The protocol is used to show on-chip fluid pumping under different flow regimes such as laminar flow and more complicated dynamics characterized by vortices and particle accumulation domains.

In this video we first describe fabrication and operation procedures of a surface acoustic wave (SAW) acoustic counterflow device. We then demonstrate an experimental setup that allows for both qualitative flow visualization and quantitative analysis of complex flows within the SAW pumping device.

Fabbricazione, il funzionamento e la visualizzazione del flusso in superficiali acustiche onda-driven Microfluidics Acoustic-controcorrente

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we ...

Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

Analysis of the size distribution of nanocrystals is a critical requirement for the processing and optimization of their size-dependent properties. The common techniques used for the size analysis are transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). These techniques, however, are not suitable for analyzing the nanocrystal size distribution in a fast, non-destructive and a reliable manner at the same time. Our aim in this work is to demonstrate that size distribution of semiconductor nanocrystals that are subject to size-dependent phonon confinement effects, can be quantitatively estimated in a non-destructive, fast and reliable manner using Raman spectroscopy. Moreover, mixed size distributions can be separately probed, and their respective volumetric ratios can be estimated using this technique. In order to analyze the size distribution, we have formulized an analytical expression of one-particle PCM and projected it onto a generic distribution function that will represent the size distribution of analyzed nanocrystal. As a model experiment, we have analyzed the size distribution of free-standing silicon nanocrystals (Si-NCs) with multi-modal size distributions. The estimated size distributions are in excellent agreement with TEM and PL results, revealing the reliability of our model.

We demonstrate how to determine the size distribution of semiconductor nanocrystals in a quantitative manner using Raman spectroscopy employing an analytically defined multi-particle phonon confinement model. Results obtained are in excellent agreement with the other size analysis techniques like transmission electron microscopy and photoluminescence spectroscopy.

Caratterizzazione di nanocristalli Dimensione distribuzione utilizzando Spettroscopia Raman con un Multi-particella Phonon confinamento Modello

Analysis of the size distribution of nanocrystals is a critical requirement for the processing and optimization of their size-dependent properties. The ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 &#176;C. Measured free dielectric constants <img alt="Equation 1" src="/files/ftp_upload/53461/image001.jpg" /> and&#160;<img alt="Equation 2" src="/files/ftp_upload/53461/image002.jpg" /> were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS.

This protocol describes the procedure of measuring the temperature dependence of the full set material constants of piezoelectric materials using resonant ultrasound spectroscopy (RUS).

Caratterizzazione del set completo Materiale costanti ed i loro dipendenza dalla temperatura dei materiali piezoelettrici Utilizzando risonanza ultrasuoni Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Capillary-based Centrifugal Microfluidic Device for Size-controllable Formation of Monodisperse Microdroplets

Here, we demonstrate a simple method for the rapid production of size-controllable, monodisperse, W/O microdroplets using a capillary-based centrifugal microfluidic device. W/O microdroplets have recently been used in powerful methods that enable miniaturized chemical experiments. Therefore, developing a versatile method to yield monodisperse W/O microdroplets is needed. We have developed a method for generating monodisperse W/O microdroplets based on a capillary-based centrifugal axisymmetric co-flowing microfluidic device. We succeeded in controlling the size of microdroplets by adjusting the capillary orifice. Our method requires equipment that is easier-to-use than with other microfluidic techniques, requires only a small volume (0.1-1 &#181;l) of sample solution for encapsulation, and enables the production of hundreds of thousands number of W/O microdroplets per second. We expect this method will assist biological studies that require precious biological samples by conserving the volume of the samples for rapid quantitative analysis biochemical and biological studies.

Here, we demonstrate a simple production method for size-controllable, monodisperse, water-in-oil (W/O) microdroplets using a capillary-based centrifugal microfluidic device. This method requires only a small sample volume and enables high-yield production. We expect this method will be useful for rapid biochemical and cellular analyses.

Centrifuga dispositivo a microfluidi capillare a base per la Formazione Size-controllabile di Monodisperse microgocce

Here, we demonstrate a simple method for the rapid production of size-controllable, monodisperse, W/O microdroplets using a capillary-based centrifugal ...

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly.

Acoustofluidic devices use ultrasonic waves within microfluidic channels to manipulate, concentrate and isolate suspended micro and nanoscopic entities. This protocol describes the fabrication and operation of such a device supporting bulk acoustic standing waves to focus particles in a central streamline without the aid of sheath fluids.

Realizzazione e di funzionamento dei dispositivi che supportano Acoustofluidic Bulk onde acustiche piedi per guaina di messa a fuoco di particelle

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must ...

Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected.

We present protocols to be used in the measurement of spray droplet size from agricultural nozzles used in both aerial and ground based agrochemical applications. These methods presented were developed to provide consistent and repeatable droplet size data both inter- and intra-laboratory, when using laser diffraction systems.

Misurare Spray Dimensione Goccia dagli ugelli agricole con laser diffrazione

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to ...

A Pipette-Tip Based Method for Seeding Cells to Droplet Microfluidic Platforms

Amongst various microfluidic platform designs frequently used for cellular analysis, droplet-microfluidics provides a robust tool for isolating and analyzing cells at the single-cell level by eliminating the influence of external factors on the cellular microenvironment. Encapsulation of cells in droplets is dictated by the Poisson distribution as a function of the number of cells present in each droplet and the average number of cells per volume of droplet. Primary cells, especially immune cells, or clinical specimens can be scarce and loss-less encapsulation of cells remains challenging. In this paper, we present a new methodology that uses pipette-tips to load cells to droplet-based microfluidic devices without the significant loss of cells. With various cell types , we demonstrate efficient cell encapsulation in droplets that closely corresponds to the encapsulation efficiency predicted by the Poisson distribution. Our method ensures loss-less loading of cells to microfluidic platforms and can be easily adapted for downstream single cell analysis, e.g., to decode cellular interactions between different cell types.

This article presents a protocol for seeding scarce population of cells using pipette-tips to droplet microfluidic devices in order to provide higher encapsulation efficiency of cells in droplets.

Metodo basato su un puntale per semina cellule a goccia microfluidici piattaforme

Amongst various microfluidic platform designs frequently used for cellular analysis, droplet-microfluidics provides a robust tool for isolating and ...