Este trabalho foi financiado por uma Saúde Aplicada BU / Cimit Fellowship Engenharia predoctoral, a Fundação Nacional de Ciência ampliando a participação pesquisa de iniciação Grant em Engenharia (BRIGE), e os Institutos Nacionais de Saúde (R21EB0094930).

1. Preparação de mudança de fase Nanoemulsion (PSNE) <ol><li> Dissolver 11 mg de DPPC e 1,68 mg de DSPE-PEG2000 em clorofórmio </li><li> Evapora-se o solvente orgânico para formar um filme de lípido seco num balão de vidro de fundo redondo de- </li><li> Dessicate a película lipídica durante a noite </li><li> Hidratar a película de lípido com 5,5 mL de salino tamponado com fosfato (PBS) </li><li> Solução de calor num banho de água a 45 ° C até que se dissolva filme lipídico, vortex periodicamente </li><li> Transferir a solução lipídica em 7 ml frasco </li><li> Sonicar solução de lípidos durante 2 min a 20% de amplitude </li><li> Dividir solução em dois frascos de 2,5 ml cada (descartar restante de 0,5 ml) </li><li> Adicionar 2,5 ml de PBS a cada frasco </li><li> Colocar cada frasco num banho de 0 ° C de água-gelo </li><li> Adicionar 50 ul TFDP a cada frasco </li><li> Sonicar cada frasco no banho de gelo-água utilizando as seguintes definições: amplitude de 25%, modo pulsado (10 seg ligado, 50 segundos desligado), total de 60 seg em vez </li><li> Trsoluções ansfer PSNE para 20 frascos de cintilação ml </li><li> Adicionar 5 ml de PBS a cada tubo, resultando em 10 ml de volume final </li><li> Montar direções Extrusor fornecidas pelo fabricante <ol><li> Lavar cada peça com água deionizada </li><li> Colocar o disco de suporte de aço inoxidável no centro da base de suporte do filtro </li><li> Coloque a malha de aço inoxidável em cima do disco de suporte de aço inoxidável </li><li> Com uma pinça, colocar uma extrusora membrana disco de drenagem (se o lado brilhante) na malha de aço inoxidável </li><li> Usando pinças, colocar o filtro de extrusora (acima do lado brilhante) na membrana de disco de drenagem </li><li> Coloque cuidadosamente o pequeno-ring no filtro e colocar o Thermobarrel e superior extrusora acima da base de apoio </li><li> Aperte parcialmente cada asa-porca primeiro, então completamente aperte as porcas de asa-com a mão em forma alternada </li><li> Ligue o extrusor parauma linha de gás nitrogênio </li><li> Para preparar o extrusor, pipeta 10 ml de água desionizada para a porta de amostra superior, limitar a abertura, e apertar a válvula de ventilação </li><li> Abrir lentamente a linha de gás de azoto para aumentar a pressão, forçando a amostra através das membranas, e recolher a amostra do tubo de saída </li><li> Após o uso, desmontar em ordem inversa, enxaguar as peças de extrusão com água desionizada, e descartar o filtro de membrana e do disco de membrana de drenagem </li></ol></li><li> Para 100 nm gotas apenas, PSNE pré-condição por extrusão 10 vezes através de 200 nm filtro </li><li> Extrude PSNE 16 vezes através de 100 nm ou 200 nm, filtro para obter uma distribuição de tamanhos estreita </li></ol> 2. Preparação do hidrogel de poliacrilamida contendo PSNE <ol><li> Preparar uma solução de 24% de BSA por diluição de 1,2 g de pó de BSA em 5 ml de água desionizada </li><li> Preparar a solução de APS a 10% diluído por 0,1 g de pó APS em 1 ml wate desionizadar </li><li> Na seguinte ordem, misturar 2,1 ml de solução de acrilamida, 1,2 ml de tampão Tris, 0,1 ml de 10% APS, 4,5 ml de 24% solução de BSA e 3,6 ml de água desionizada na câmara de plástico </li><li> Aquece-se a 40 ° C e colocar sob vácuo durante 1 hr </li><li> Adicionar 480 ul de PSNE e misturar completamente por agitação suave da câmara de plástico. </li><li> Adicionar 12 ul de TEMED e colocar a câmara num banho de água a 12 ° C durante 2 h </li></ol> 3. Resultados representativos Um esquema da instalação de ultra-som para experiências com fantasmas tecido mimetizam de hidrogel é apresentado na Figura 1. Este protocolo resulta em gotículas de lípidos revestidos perfluorocarbono com uma distribuição estreita de tamanhos, que são estáveis ​​em solução, durante pelo menos uma semana. A distribuição do tamanho medido com dispersão de luz dinâmica (90Plus Analisador de Tamanho de Partículas, Brookhaven Instruments, Holtsville, NY) é mostrado na Figura 2 para PSNE extrudida utilizando 100 e 200filtros nm. O diâmetro PSNE eficaz ao longo do tempo, medida usando dispersão dinâmica de luz, está listado na Tabela 1, demonstram que PSNE são estáveis ​​durante pelo menos uma semana. B-modo as imagens de PSNE antes e depois vaporização num hidrogel de poliacrilamida são apresentadas na Figura 3. Além disso, a lesão formada por 15 segundos de HIFU mediada por aquecimento num hidrogel de poliacrilamida contendo albumina e PSNE é mostrado na Figura 4. A forma assimétrica da lesão é um resultado do aquecimento prefocal que ocorre devido à presença de uma nuvem de bolhas no caminho de ultra-som. É importante notar que o aquecimento prefocal e formação da lesão, devido à dispersão das bolhas podem ser minimizados através da redução da energia acústica transmitida. <img src="/files/ftp_upload/4308/4308fig1.jpg" alt="Figura 1"/> Figura 1. Diagrama esquemático do arranjo experimental de ultra-som para experiências com tecidos mim-Icking hidrogéis. <img src="/files/ftp_upload/4308/4308fig2.jpg" alt="Figura 2"/> Figura 2. Tamanho distribuição de PSNE extrudida através de 100 nm ou 200 nm, filtros, medida usando dispersão dinâmica de luz. As unidades dos eixos de ordenadas são baseados na intensidade da luz dispersa a partir de partículas de um certo tamanho em relação à intensidade total da luz dispersa a partir da amostra. <img src="/files/ftp_upload/4308/4308fig3.jpg" alt="Figura 3"/> Figura 3. B-modo imagens (a) antes e (b) depois de vaporização PSNE num hidrogel de poliacrilamida. A seta indica a região focal onde uma nuvem de bolhas foi formada por vaporização PSNE. <img src="/files/ftp_upload/4308/4308fig4.jpg" alt="Figura 4"/> Figura 4. Imagens de polyacrylamide hidrogel contendo albumina e PSNE (a) antes e (b), após a vaporização e sonicação com HIFU, demonstrando a formação da lesão, como resultado de ultra-som induzida pelo aquecimento. A freqüência central de ultra-som foi de 3,3 MHz. O sinal de ultra-som de um composto inicial de 30-ciclo, 6,4 W de pulso para vaporizar PSNE, imediatamente seguido de 15 segundos de ultra-som contínuo em 0,77 W. <table border="1"><tbody><tr><td rowspan="2"> Dias após a extrusão </td><td colspan="2"> Extrudido com filtro de 200 nm </td><td colspan="2"> Extrudido com filtro de 100 nm </td></tr><tr><td> A média de Dia. (Nm) </td><td> Std. Desenv. (Nm) </td><td> A média de Dia. (Nm) </td><td> Std. Desenv. (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> Tabela 1. Diâmetro médio e desvio padrão de PSNE a um e sete dias após a extrusão com 100 nm e 200 nm filtros.

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Ultra-som de alta intensidade focado (HIFU) é utilizada clinicamente para remoção térmica de tumores. 1 Para melhorar o aquecimento localizado e melhorar a ablação térmica de tumores, as gotas revestidas com lípido perfluorocarbonos têm sido desenvolvidos, que pode ser vaporizada por HIFU. A vasculatura em muitos tumores é anormalmente leaky devido ao seu crescimento rápido. 2 Assim, as nanopartículas são capazes de penetrar as fenestrações e passivamente acumular dentro de tumores, ...

<table border="1"><tbody><tr><td> Nome comum </td><td> Fabricante </td><td> Gato. Número </td><td> Nome Completo / Descrição </td></tr><tr><td> DPPC </td><td> Lipídios Avanti, Alabaster, AL, EUA </td><td> 850355P </td><td> 1,2-dipalmitoil-sn-glicero-3-fosfocolina </td></tr><tr><td> DSPE-PEG2000 </td><td> Lipídios Avanti, Alabaster, AL, EUA </td><td> 880120P </td><td> 1,2-distearoil-sn-glicero-3-fosfoetanolamina-N-[metoxi (polietileno glicol) -2000] (sal de amónio) </td></tr><tr><td> TFDP </td><td> Fluoromed, Round Rock, Texas, EUA </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, EUA </td><td> P2194 </td><td> Salina tamponada com fosfato </td></tr><tr><td> Clorofórmio </td><td> Sigma-Aldrich, St. Louis, MO, EUA </td><td> 372978 </td><td> Clorofórmio </td></tr><tr><td> Acrilamida </td><td> Sigma-Aldrich, St. Louis, MO, EUA </td><td> A9926 </td><td> 40% 19:01 de acrilamida / bis-acrilamida </td></tr><tr><td> Tampão Tris </td><td> Sigma-Aldrich, St. Louis, MO, EUA </td><td> T2694 </td><td> 1M, pH 8, o cloridrato de trizma e base Trizma </td></tr><tr><td> BSA </td><td> Sigma-Aldrich, St. Louis, MO, EUA </td><td> A3059 </td><td> Albumina de soro bovino </td></tr><tr><td> APS </td><td> Sigma-Aldrich, St. Louis, MO, EUA </td><td> A3678 </td><td> Solução de persulfato de amónio </td></tr><tr><td> TEMED </td><td> Sigma-Aldrich, St. Louis, MO, EUA </td><td> 87689 </td><td> N, N, N &#39;, N&#39;-tetrametiletilenodiamina </td></tr><tr><td></td><td></td><td></td><td> Equipamento </td></tr><tr><td> Sonicador (3 ponta mm) </td&gt; <td> Sonics &amp; Materials, Inc., Newtown, CT, EUA </td><td> Vibra-Cell </td><td></td></tr><tr><td> Banho de água </td><td> Thermo Fisher Scientific, Waltham, MA, EUA </td><td> Neslab EX-7 </td><td></td></tr><tr><td> Extrusora </td><td> Lipídeos do Norte, em Burnaby, BC, Canadá </td><td> Lipex </td><td></td></tr><tr><td> Filtros extrusora </td><td> Whatman, Piscataway, NJ, EUA </td><td> Nuclepore # 110605 e # 110606 </td><td></td></tr><tr><td> Extrusora drenagem Disco </td><td> Sterlitech Corporation, Kent, WA, EUA </td><td> # PETEDD25100 </td><td></td></tr><tr><td> Câmara de plástico </td><td> EUA Plastic Corporation, Lima, OH, EUA </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

Ultra-som de alta intensidade focado (HIFU) é utilizada clinicamente para remoção térmica de tumores. Para aumentar o aquecimento localizado e melhorar a ablação térmica de tumores, as gotas revestidas com lípido perfluorocarbonos têm sido desenvolvidos, que pode ser vaporizada por HIFU. A vasculatura em muitos tumores é anormalmente leaky devido ao seu rápido crescimento, e as nanopartículas são capazes de penetrar as fenestrações e passivamente acumulam no interior dos tumores. Assim, controlando o tamanho das gotículas pode resultar em melhor acumulação no interior dos tumores. Neste relatório, a preparação de gotas estáveis ​​em uma nanoemulsão de deslocamento de fase (PSNE), com uma estreita distribuição de tamanho é descrito. PSNE foram sintetizados por sonicação de uma solução de lípido na presença de perfluorocarbono líquido. Uma distribuição estreita de tamanhos foi obtida por extrusão das vezes PSNE múltiplas utilizando filtros com tamanhos de poros de 100 ou 200 nm. A distribuição de tamanho foi medido ao longo de um período de 7 dias usando dispersão dinâmica de luz. Polyachidrogéis rylamide contendo PSNE estavam preparados para experimentos in vitro. Gotículas PSNE nos hidrogéis foram vaporizados com ultra-sons e as bolhas resultantes melhoradas aquecimento localizado. Vaporizado PSNE permite um aquecimento mais rápido e também reduz a intensidade ultra-som necessária para a ablação térmica. Assim, espera-se que PSNE melhorar a ablação térmica em tumores, melhorando potencialmente a resultados terapêuticos do HIFU mediadas tratamentos de ablação térmica.

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 nanoemulsões (PSNE) pode ser vaporizado utilizando ultra-sons de alta intensidade focado para melhorar o aquecimento localizado e melhorar a ablação térmica de tumores. Neste relatório, a preparação de PSNE estável, com uma estreita distribuição de tamanho é descrito. Além disso, o impacto de PSNE vaporizada no ultra-som mediada por ablação é demonstrada no tecido mimetizam fantasmas.

Síntese de mudança de fase Nanoemulsões com distribuição de tamanho estreita para vaporização Droplet Acústico e Bubble avançada ablação por ultrassom mediada

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 visualizações.  Boston University. Phase-Shift nanoemulsões (PSNE) pode ser vaporizado utilizando ultra-sons de alta intensidade focado para melhorar o aquecimento localizado e melhorar a ablação térmica de tumores. Neste relatório, a preparação de PSNE estável, com uma estreita distribuição de tamanho é descrito. Além disso, o impacto de PSNE vaporizada no ultra-som mediada por ablação é demonstrada no tecido mimetizam fantasmas.

Vídeo: 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.

Controlando o tamanho, forma e estabilidade de Polímeros Supramoleculares na Água

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

Engenharia

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.

Síntese e Operação de Fluorescente-core microcavidades de Sensoriamento refractométricos

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 de fabricação de microestruturas tridimensionais usando vaporização de um componente sacrificial

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.

Fabricação, Operação e Visualização de Fluxo em superfície acústico de ondas orientadas Microfluidics acústico contrafluxo

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.

Caracterização de nanocristal Tamanho Distribution utilizando Espectroscopia Raman com um Multi-partícula Phonon Confinamento Modelo

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).

Caracterização do conjunto completo de constantes do material e sua dependência de temperatura para materiais piezoelétricos Usando Resonant Ultrasound 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.

Dispositivo micro centrífuga baseada capilar para a Formação tamanho controlável de Monodisperse microgotas

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.

Fabricação e operação de Acoustofluidic dispositivos que suportam a granel ondas acústicas pe para Sheathless Focando de Partículas

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.

Medir o tamanho do pulverizador Gota de bicos agrícolas Usando Laser Difração

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.

Método baseado em uma ponta da pipeta para semeadura pilhas Droplet Microfluidic plataformas

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