FM reconoce el financiamiento de la ANR a través de una chaire d&#39;Excellence IDEX Sorbonne Paris Cité, el INSU través de una subvención PNP, el Instituto Universitario de Francia, así como el programa Labex UniverEarth en la Sorbona de París Cité (ANR-10-LabX-0023 y la ANR -11-IDEX-0005-02). También agradecemos a la financiación del Consejo Europeo de Investigación en virtud de la Comunidad Europea H2020 Programa Marco / ERC acuerdo de subvención # 637503 (prístina).

NOTA: Los procedimientos con animales han sido aprobados por el Cuidado y Uso de Animales Comité Institucional (IACUC) en la Université Paris Diderot. 1. Preparación de los materiales <ol><li> Sub-ebullición destilar 1 L de los ácidos (HNO 3, HBr) con el fin de purificarlos de la impureza. </li><li> Limpie los vasos y adaptador de punta en un caliente (~ 100 ° C) concentra HNO 3 baño ácido durante al menos dos días. </li><li> Lavar las puntas de pipeta en un resfriado 3 N HNO 3 baño durante varios días y enjuagar individualmente tres veces con agua desionizada. </li></ol> Preparación 2. Muestra <ol><li> Anestesiar a los ratones por inyección intraperitoneal de ketamina y xilazina. Evaluar la anestesia por el método pizca dedo del pie. </li><li> Recoger la sangre por una punción cardiaca en presencia de heparina en tubos de 1,5 ml. </li><li> Separar el plasma de los glóbulos por centrifugación (10 min, 1500 xg) y transferir el plasma a polipropileno cviales ryogenic utilizando puntas de polipropileno. </li><li> Retire la sangre restante a partir de órganos por el corte de la vena hepática y la inyección de DPBS a través del corazón. Evaluar la muerte del ratón por dislocación cervical. </li><li> Cosecha de los órganos con instrumentos de acero inoxidable estériles, liberarlos de la grasa que rodea su caso, y SNAP-congelarlos en polipropileno viales criogénicos. </li></ol> 3. Química Purificación <ol><li> En primer lugar, disolver las muestras en una mezcla de ~ 1 ml de concentrado (30%) H 2 O 2 y ~ 1 ml de concentrado (~ 15 M) HNO 3. ¿Todos estos pasos dentro de una campana de humos. <ol><li> Colocar todo el órgano de interés en un vaso de precipitados de teflón 15 ml. A continuación, añadir el H 2 O 2 / HNO 3 al vaso 5. Mantenga el vaso de precipitados abierto durante unos minutos con el fin de evitar salpicaduras debido a la reacción de oxidación de la materia orgánica y la liberación de CO 2. </li><li> Por último, poner el vaso de precipitados sobre una placa caliente a about 100 ° C durante un par de horas o hasta que la solución es perfectamente claro. </li></ol></li><li> Abrir el vaso de precipitados y secar la solución sobre una placa caliente a aproximadamente 100 ° C. </li><li> Una vez que la muestra está seca, añadir 1 ml de 1,5 N HBr a las muestras; cerrar el vaso y deje que se disuelva en una placa caliente a 100 ° C durante un par de horas. </li><li> Mientras tanto preparar las 500 columnas mu l. <ol><li> Añadir 500 l de la resina de malla AG1X8 200-400 a la columna y lo puso en el estante de la columna con un vaso de la basura debajo de ella. Lavar la resina alternando: 5 ml de 18,2 mO ⋅ cm de agua, 5 ml de 0,5 N HNO 3, 5 ml de agua, 5 ml de 0,5 N HNO 3, y luego 5 ml de agua. Acondicionar la resina con 5 ml de 1,5 N HBr. </li></ol></li><li> Retire los vasos de la placa caliente y los puso en un baño de ultrasonidos durante aproximadamente 30 minutos, y luego dejar que los vasos se enfríen a temperatura ambiente. </li><li> Una vez que el vaso de precipitados se enfrió y la resina se lava, abra el vaso de precipitados. Ponga el adaptador de punta a tél jeringa, añadir una punta de pipeta; pipetear los 1 ml de muestra y cargarlo en la resina (muy lentamente a fin de no agitar la resina). </li><li> Una vez que todo el líquido pasa a través de la columna, añadir 5 ml de 1,5 N HBr. </li><li> Una vez que los 5 ml de 1,5 N HBr pasan a través de la columna, reemplazar el vaso de precipitados de basura con un limpio vaso de precipitados de 15 ml. </li><li> Añadir 5 ml de 0,5 N HNO 3 2,5 ml a la vez. En esta etapa el Zn se eluye de la resina. </li><li> Una vez 5 ml de HNO 3 pasa a través de la columna, retire el vaso de precipitados y colocarlo en una placa caliente a 100 ° C hasta que se seca. </li><li> Retire la columna del soporte columna; trash la resina (usar una nueva resina para cada muestra). </li><li> Una vez que la muestra está seca, repetir el protocolo con el mismo volumen de ácidos sobre una columna más pequeña (100 l) y luego se coloca en un plato caliente hasta que se seca. La muestra está ahora listo para espectrometría de masas. </li></ol> 4. Masa-espectrometría de Medición <ol><li> Analizar el compo isotópica Znsición en un colector acoplado inductivamente espectrómetro de masas con plasma multi (MC-ICP-MS). <ol><li> Utilice los parámetros de la máquina que se resumen en la Tabla 1. </li></ol></li><li> Coloque las tazas de Faraday para recoger en masa (m / z) de 62 Ni, 63 Cu, Zn 64, 65 Cu, Zn 66, 67 y 68 de Zn Zn. </li><li> Preparar una solución que contiene Zn 500 ppb en 0,1 M HNO 3 para el análisis isotópico. </li><li> Analizar la solución 500 ppb de Zn mediante el uso de una cámara de pulverización combinada con un / nebulizador teflón min 100 l. Para cada muestra, mida 30 exploraciones (1 bloque de 30 ciclos) en la que el tiempo de integración de cada exploración es 8,389 seg. </li><li> Corrija el fondo restando las intensidades de cero en pico de una solución en blanco (la M HNO 3 0,1 solución utilizada para volver a disolver las muestras). </li><li> Control y corregir posibles 64 Ni interferencia isobárica mediante la medición de la intensidad del pico 62 Ni.Suponga que la relación 62 64 Ni / Ni es algo natural (0.2548), corregir el valor del sesgo masa instrumental, y luego retire el 64 Ni en la masa 64 como: 64 Zn reales = 64 Zn medido - 64 Ni = 64 Zn medido - (64 Ni / 62 Ni) naturales x 62 mide Ni. </li><li> Corregir el sesgo masa instrumental de horquillado cada una de las muestras con una solución de 500 ppb de la norma JMC Lyon Zn (u otro estándar disponibles, tales como IRMM-3702). Realizar el horquillado estándar dividiendo la relación Zn Zn 66/64 de la muestra por el promedio de la relación Zn Zn 66/64 de los dos estándares medidos antes y después de la muestra menos 1 y multiplicada por 1000 (véase la ecuación 1). Precisión externa típica en el estándar JMC Lyon Zn es 0,05 permil / amu (2 desviación estándar, 2 sd). </li></ol>

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Los autores no tienen nada que revelar.

La reproducibilidad de las mediciones se evalúa a través de análisis replicados de las mismas muestras realizadas durante las diferentes sesiones de análisis. Por ejemplo 6, hemos reproducido la misma roca terrestre 7 veces y hemos obtenido los resultados presentados en la Tabla 2. Como se esperaba de la teoría de fraccionamiento isotópico 10 y como se mide en cualquier material sistema solar hasta el momento (por ejemplo, meteorito ...

La medición de alta precisión (mejor que 100 ppm / unidad de masa atómica) de zinc composición de isótopos estables sólo ha sido posible por cerca de 15 años gracias al desarrollo de varios colectores de plasma de código espectrómetros de masa y desde entonces ha sido aplicado en su mayoría en la Tierra y las ciencias planetarias. Las aplicaciones en el campo médico son nuevos y tienen un fuerte potencial como biomarcadores para enfermedades que modifican el metabolismo del zinc (por ejemplo, enfermedad de Alzheimer). Este trabajo presenta un método para medir con alta precisión las proporciones de isótopos estables naturales de zinc en diversos órganos de ratón. Lo mismo sería aplicable a muestras humanas. El método consiste en la disolución de los órganos, la purificación química de zinc del resto de los átomos, y luego el análisis de la relación isotópica en un espectrómetro de masas. La calidad de Zn mediciones isotópicas depende de la calidad de la purificación química (pureza de Zn, bajo un borrador en blancoared a la cantidad de Zn presente en la muestra, rendimiento alto química del procedimiento) y en el control del sesgo instrumental. Se necesita la alta pureza de la fracción de Zn final para eliminar ambos interferencias isobáricas e interferencias no isobárica que crean un efecto de la matriz. Nucleidos isobáricas crean interferencias directas (por ejemplo, 64 Ni). Interferencias no isobáricas generan el llamado efecto de &quot;matriz&quot; y alteran la precisión analítica de las mediciones por el cambio de la condición de la ionización en comparación con el estándar de zinc puro a la que las muestras se comparan con 1. Un bajo blanco (&lt;10 ng) indica que no hay contaminación de las muestras por Zn externa que sesgo la composición isotópica medido. Como isótopos de Zn pueden fraccionarse durante la cromatografía de intercambio iónico 2, la colección de todos los átomos de Zn asegura que ningún fraccionamiento isotópico se produce, lo que implica que el procedimiento químico debe tener un rendimiento completo. Por último, la corrección del fraccionamiento isotópico decisivo durante la medición espectrometría de masas se realiza mediante el método de &quot;horquillado estándar&quot;. Por lo tanto, las principales dificultades para obtener mediciones precisas son el control de la contaminación externa (es decir, baja en blanco), la producción de una purificación química pleno rendimiento que está limpio de cualquier otros átomos o moléculas, y corregir el fraccionamiento isotópico instrumental en el espectrómetro de masas. En este artículo vamos a describir nuestro protocolo de análisis para separar Zn de los órganos de ratón, así como las mediciones de espectrometría de masas. La extracción se realiza usando una baja cantidad de ácidos diluidos (HBr / HNO 3 medios de comunicación) en micro-columnas (0.5 mu l y 0,1 mu l) de resina de intercambio aniónico. Tiene un rendimiento total y las mediciones tienen una reproducibilidad externa mejor que 50 ppm en la relación de 66 Zn / Zn 64. Otra ventaja de la metod es que es muy rápido. El método está por lo tanto muy bien adaptada a las ciencias médicas, en el que uno tiene que analizar un gran número de muestras en comparación con ciencias de la tierra, donde se desarrollaron estos métodos analíticos.

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			<td height="42" style="height:42px;width:236px;">Name of Material/ Equipment</td>
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			<td style="width:99px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
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			<td height="42" style="height:42px;width:236px;">Multi-collection inductively-coupled-plasma mass-spectromter</td>
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			<td height="21" style="height:21px;">Anion-exchange resin AG1 X8 200-400</td>
			<td style="width:99px;">Bio-Rad</td>
			<td colspan="2">140-1443-MSDS</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:236px;">teflon beakers</td>
			<td style="width:99px;">Savillex&#160;</td>
			<td>200-015-12</td>
			<td></td>
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		<tr height="42">
			<td height="42" style="height:42px;width:236px;">Home-made teflon colunms made with shrinkable teflon</td>
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			<td style="width:99px;"></td>
			<td></td>
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high precision zinc isotopic measurements applied to mouse organs

Se presenta un procedimiento para medir con alta precisión las proporciones de isótopos de zinc en órganos de ratón. Zinc se compone de 5 isótopos estables (64 Zn, Zn 66, 67, 68 Zn Zn y Zn) 70 que se fraccionan naturalmente entre los órganos de ratón. En primer lugar, mostramos cómo disolver los diferentes órganos con el fin de liberar a los átomos de Zn; este paso se realiza por una mezcla de HNO 3 y H 2 O 2. A continuación, purificamos los átomos de zinc de todos los otros elementos, en particular de interferencias isobáricas (por ejemplo, Ni), por cromatografía de intercambio aniónico en un / HNO 3 HBr medio diluido. Estos dos primeros pasos se realizan en un laboratorio limpio utilizando productos químicos de alta pureza. Por último, las proporciones de isótopos se miden usando un multi-colector-plasma de acoplamiento inductivo-espectrómetro de masas, en baja resolución. Las muestras se inyectaron usando una cámara de pulverización y el fraccionamiento isotópico inducido por el espectrómetro de masas es corrected mediante la comparación de la relación de las muestras a la relación de un estándar (técnica de horquillado estándar). Este procedimiento típico completo produce una relación isotópica con un 50 ppm (2 sd) reproducibilidad.

En 1,5 N HBr, las principales especies de zinc (ZnBr3-) forma complejos muy fuertes con la resina de intercambio de aniones, mientras que la mayoría de otros elementos no interactúan con la resina. El zinc se recupera a continuación cambiando el medio a HNO 3 diluido, el cambio de la especiación de Zn a Zn 2+ que se libera de la resina de 6,7. Las relaciones de isótopos se expresan típicamente como partes por 1000 desviaciones relativas a un estándar: ...

Watch this Scientific Journal Video about High Precision Zinc Isotopic Measurements Applied to Mouse Organs at JoVE.com

High Precision Zinc Isotopic Measurements Applied to Mouse Organs

We present the technique to measure with high precision zinc isotope ratios in mouse organs.

Altas medidas de precisión de zinc isotópicos aplicados a Ratón Órganos

We present a procedure to measure with high precision zinc isotope ratios in mouse organs. Zinc is composed of 5 stable isotopes (64Zn, 66Zn, 67Zn, 68Zn ...

high-precision-zinc-isotopic-measurements-applied-to-mouse-organs

Research

JoVE Journal

Chemistry

7.4K vistas.  Université Paris Diderot. We present the technique to measure with high precision zinc isotope ratios in mouse organs.

Video: High Precision Zinc Isotopic Measurements Applied to Mouse Organs

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40&#160;&#176;C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure.
The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)1-4. For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather accurate and reproducible measurements in a timely fashion.

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus is a unique tool to study, without sampling, phase behavior under a wide range of pressures. Using a cathetometer, very precise volume measurements can be recorded to measure liquid expansion and phase composition. Thus, this synthetic method enables the study of (1) phase equilibria of multi-component mixtures and (2) the partition behavior of catalyst or model compounds as a function of pressure.

De alta presión de la célula de zafiro para la Fase Equilibrios mediciones de CO<sub&gt; 2</sub&gt; / Orgánicos / Sistemas de Agua

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. ...

Investigación

Química

Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films

This report aims to fully describe the experimental technique of using ellipsometry for cooling rate dependent Tg (CR-Tg) experiments. These measurements are simple high-throughput characterization experiments, which can determine the glass transition temperature (Tg), average dynamics, fragility and the expansion coefficient of the super-cooled liquid and glassy states for a variety of glassy materials. This technique allows for these parameters to be measured in a single experiment, while other methods must combine a variety of different techniques to investigate all of these properties. Measurements of dynamics close to Tg are particularly challenging. The advantage of cooling rate dependent Tg measurements over other methods which directly probe bulk and surface relaxation dynamics is that they are relatively quick and simple experiments, which do not utilize fluorophores or other complicated experimental techniques. Furthermore, this technique probes the average dynamics of technologically relevant thin films in temperature and relaxation time (&#964;&#945;) regimes relevant to the glass transition (&#964;&#945; &#62; 100 sec). The limitation to using ellipsometry for cooling rate dependent Tg experiments is that it cannot probe relaxation times relevant to measurements of viscosity (&#964;&#945; &#60;&#60; 1 sec). Other cooling rate dependent Tg measurement techniques, however, can extend the CR-Tg method to faster relaxation times. Furthermore, this technique can be used for any glassy system so long as the integrity of the film remains throughout the experiment.

Here, we present a protocol for cooling rate dependent ellipsometry experiments, which can determine the glass transition temperature (Tg), average dynamics, fragility and the expansion coefficient of the super-cooled liquid and glass for a variety of glassy materials.

Enfriamiento Puntúa Medidas Elipsometría Dependientes para determinar la dinámica de Thin Films vidriosos

This report aims to fully describe the experimental technique of using ellipsometry for cooling rate dependent Tg (CR-Tg) experiments. These measurements ...

Immunostaining Phospho-epitopes in Ciliated Organs of Whole Mount Zebrafish Embryos

The rapid proliferation of cells, the tissue-specific expression of genes and the emergence of signaling networks characterize early embryonic development of all vertebrates. The kinetics and location of signals - even within single cells - in the developing embryo complements the identification of important developmental genes. Immunostaining techniques are described that have been shown to define the kinetics of intracellular and whole animal signals in structures as small as primary cilia. The techniques for fixing, imaging and processing images using a laser-scanning confocal compound microscope can be completed in as few as 36 hr.
Zebrafish (Danio rerio) is a desirable organism for investigators who seek to conduct studies in a vertebrate species that is affordable and relevant to human disease. Genetic knockouts or knockdowns must be confirmed by the loss of the actual protein product. Such confirmation of protein loss can be achieved using the techniques described here. Clues into signaling pathways can also be deciphered by using antibodies that are reactive with proteins that have been post-translationally modified by phosphorylation. Preserving and optimizing the phosphorylated state of an epitope is therefore critical to this determination and is accomplished by this protocol.
This study describes techniques to fix embryos during the first 72 hr of development and co-localize a variety of relevant epitopes with cilia in the Kupffer&#39;s Vesicle (KV), the kidney and the inner ear. These techniques are straightforward, do not require dissection and can be completed in a relatively short period of time. Projecting confocal image stacks into a single image is a useful means of presenting these data.

Techniques are described to immunostain phospho-epitopes in whole zebrafish embryos and then conduct two-color fluorescent confocal localization in cellular structures as small as primary cilia. The techniques for fixing and imaging can define the location and kinetics of the appearance or activation of specific proteins.

Inmunotinción fosfo-epítopos en ciliadas Órganos de todo el montaje embriones de pez cebra

The rapid proliferation of cells, the tissue-specific expression of genes and the emergence of signaling networks characterize early embryonic development ...

Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)

Fire-derived, pyrogenic carbon (PyC), sometimes called black carbon (BC), is the carbonaceous solid residue of biomass and fossil fuel combustion, such as char and soot. PyC is ubiquitous in the environment due to its long persistence, and its abundance might even increase with the projected increase in global wildfire activity and the continued burning of fossil fuel. PyC is also increasingly produced from the industrial pyrolysis of organic wastes, which yields charred soil amendments (biochar). Moreover, the emergence of nanotechnology may also result in the release of PyC-like compounds to the environment. It is thus a high priority to reliably detect, characterize and quantify these charred materials in order to investigate their environmental properties and to understand their role in the carbon cycle.
Here, we present the benzene polycarboxylic acid (BPCA) method, which allows the simultaneous assessment of PyC&#39;s characteristics, quantity and isotopic composition (13C and 14C) on a molecular level. The method is applicable to a very wide range of environmental sample materials and detects PyC over a broad range of the combustion continuum, i.e., it is sensitive to slightly charred biomass as well as high temperature chars and soot. The BPCA protocol presented here is simple to employ, highly reproducible, as well as easily extendable and modifiable to specific requirements. It thus provides a versatile tool for the investigation of PyC in various disciplines, ranging from archeology and environmental forensics to biochar and carbon cycling research.

Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids BPCA

We present the benzene polycarboxylic acid (BPCA) method for assessing pyrogenic carbon (PyC) in the environment. The compound-specific approach uniquely provides simultaneous information about the characteristics, quantity and isotopic composition (13C and 14C) of PyC.

Caracterización, cuantificación y compuesto específico análisis isotópico de carbono Pirogenica utilizando benceno policarboxílicos (BPCA)

Fire-derived, pyrogenic carbon (PyC), sometimes called black carbon (BC), is the carbonaceous solid residue of biomass and fossil fuel combustion, such as ...

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry

Chemical analysis of volatile and semivolatile compounds dissolved in liquid samples can be challenging. The dissolved components need to be brought to the gas phase, and efficiently transferred to a detection system. Fizzy extraction takes advantage of the effervescence phenomenon. First, a carrier gas (here, carbon dioxide) is dissolved in the sample by applying overpressure and stirring the sample. Second, the sample chamber is decompressed abruptly. Decompression leads to the formation of numerous carrier gas bubbles in the sample liquid. These bubbles assist the release of the dissolved analyte species from the liquid to the gas phase. The released analytes are immediately transferred to the atmospheric pressure chemical ionization interface of a triple quadrupole mass spectrometer. The ionizable analyte species give rise to mass spectrometric signals in the time domain. Because the release of the analyte species occurs over short periods of time (a few seconds), the temporal signals have high amplitudes and high signal-to-noise ratios. The amplitudes and areas of the temporal peaks can then be correlated with concentrations of the analytes in the liquid samples subjected to fizzy extraction, which enables quantitative analysis. The advantages of fizzy extraction include: simplicity, speed, and limited use of chemicals (solvents).

Fizzy extraction is a new laboratory technique for analysis of volatile and semivolatile compounds. A carrier gas is dissolved in the liquid sample by applying overpressure and stirring the sample. The sample chamber is then decompressed. The analyte species are liberated to the gas phase due to effervescence.

Fizzy Extracción de Compuestos Orgánicos Volátiles Combinado con la Presión Atmosférica Ionización Química Espectrometría de Masa Cuadrupolar

Chemical analysis of volatile and semivolatile compounds dissolved in liquid samples can be challenging. The dissolved components need to be brought to ...

Aerosol-assisted Chemical Vapor Deposition of Metal Oxide Structures: Zinc Oxide Rods

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, their high cost production and/or incompatibility with microfabrication technologies, due to the use of pre-deposited catalyst-seeds and/or high processing temperatures exceeding 900 &#176;C, represent a drawback for a widespread use of these methods. Here, however, we report the synthesis of ZnO rods via a non-catalyzed vapor-solid mechanism enabled by using an aerosol-assisted chemical vapor deposition (CVD) method at 400 &#176;C with zinc chloride (ZnCl2) as the precursor and ethanol as the carrier solvent. This method provides both single-step formation of ZnO rods and the possibility of their direct integration with various substrate types, including silicon, silicon-based micromachined platforms, quartz, or high heat resistant polymers. This potentially facilitates the use of this method at a large-scale, due to its compatibility with state-of-the-art microfabrication processes for device manufacture. This report also describes the properties of these structures (e.g., morphology, crystalline phase, optical band gap, chemical composition, electrical resistance) and validates its gas sensing functionality towards carbon monoxide.

Columnar zinc oxide structures in the form of rods are synthesized via aerosol-assisted chemical vapor deposition without the use of pre-deposited catalyst-seed particles. This method is scalable and compatible with various substrates based on either silicon, quartz or polymers.

Aerosol-asistida por deposición de Vapor químico del óxido de Metal estructuras: barras de óxido de Zinc

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, ...

High Resolution Physical Characterization of Single Metallic Nanoparticles

Individual molecules can be detected and characterized by measuring the degree by which they reduce the ionic current flowing through a single nanometer-scale pore. The signal is characteristic of the molecule&#39;s physicochemical properties and its interactions with the pore. We demonstrate that the nanopore formed by the bacterial protein exotoxin Staphylococcus aureus alpha hemolysin (&#945;HL) can detect polyoxometalates (POMs, anionic metal oxygen clusters), at the single molecule limit. Moreover, multiple degradation products of 12-phosphotungstic acid POM (PTA, H3PW12O40) in solution are simultaneously measured. The single molecule sensitivity of the nanopore method allows for POMs to be characterized at significantly lower concentrations than required for nuclear magnetic resonance (NMR) spectroscopy. This technique could serve as a new tool for chemists to study the molecular properties of polyoxometalates or other metallic clusters, to better understand POM synthetic processes, and possibly improve their yield. Hypothetically, the location of a given atom, or the rotation of a fragment in the molecule, and the metal oxidation state could be investigated with this method. In addition, this new technique has the advantage of allowing the real-time monitoring of molecules in solution.&#160;

Here, we present a protocol to detect discrete metal oxygen clusters, polyoxometalates (POMs), at the single molecule limit using a biological nanopore-based electronic platform. The method provides a complementary approach to traditional analytical chemistry tools used in the study of these molecules.

Caracterización física de alta resolución de nanopartículas metálicas únicas

Individual molecules can be detected and characterized by measuring the degree by which they reduce the ionic current flowing through a single ...

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method

The single deuterium substitution in porphycene leads to an asymmetric molecular geometry, which may affect the double proton transfer process in the porphycene molecule. In this study, we applied an enhanced QM/MM method called SITS-QM/MM to investigate hydrogen/deuterium (H/D) isotope effects on the double proton transfer in porphycene. Distance changes in SITS-QM/MM molecular dynamics simulations suggested that the deuterium substituted porphycene adopted the stepwise double proton transfer mechanism. The structural analysis and the free energy shifts of double proton transfer process indicated that the asymmetric isotopic substitution subtly compressed the covalent hydrogen bonds and may alter the original transition state location.

A protocol that uses enhanced QM/MM method to investigate the isotopic effect on the double proton transfer process in porphycene is presented here.

Efecto isotópico en el proceso de transferencia de doble protones de porficeno investigado por el método QM/MM mejorado

The single deuterium substitution in porphycene leads to an asymmetric molecular geometry, which may affect the double proton transfer process in the ...

Automated Sample Multiplexing by using Combined Precursor Isotopic Labeling and Isobaric Tagging (cPILOT)

We have introduced a high throughput quantitative proteomics workflow, combined precursor isotopic labeling and isobaric tagging (cPILOT) capable of multiplexing up to 22 or 24 samples with tandem mass tags or isobaric N,N-dimethyl leucine isobaric tags, respectively, in a single experiment. This enhanced sample multiplexing considerably reduces mass spectrometry acquisition times and increases the utility of the expensive commercial isobaric reagents. However, the manual process of sample handling and pipetting steps in the strategy can be labor intensive, time consuming, and introduce sample loss and quantitative error. These limitations can be overcome through the incorporation of automation. Here we transferred the manual cPILOT protocol to an automated liquid handling device that can prepare large sample numbers (i.e., 96 samples) in parallel. Overall, automation increases feasibility and reproducibility of cPILOT and allows for broad usage by other researchers with comparable automation devices.

Automated Sample Multiplexing by using Combined Precursor Isotopic Labeling and Isobaric Tagging cPILOT

Combined precursor isotopic labeling and isobaric tagging (cPILOT) is an enhanced sample multiplexing strategy that is capable of increasing the number of samples that can be analyzed simultaneously with available isobaric tags. Incorporation of a robotic platform has greatly increased experimental throughput, reproducibility, and quantitative accuracy.

Multiplexación automática de muestras mediante el etiquetado isotópico de precursor combinado y el etiquetado isobárico (cPILOT)

We have introduced a high throughput quantitative proteomics workflow, combined precursor isotopic labeling and isobaric tagging (cPILOT) capable of ...

Zinc-Sponge Battery Electrodes that Suppress Dendrites

We report two methods to create zinc-sponge electrodes that suppress dendrite formation and shape change for rechargeable zinc batteries. Both methods are characterized by creating a paste made of zinc particles, organic porogen, and viscosity-enhancing agent that is heated under an inert gas and then air. During heating under the inert gas, the zinc particles anneal together, and the porogen decomposes; under air, the zinc fuses and residual organic burns out, yielding an open-cell metal foam or sponge. We tune the mechanical and electrochemical properties of the zinc sponges by varying zinc-to-porogen mass ratio, heating time under inert gas and air, and size and shape of the zinc and porogen particles. An advantage of the reported methods is their ability to finely tune zinc-sponge architecture. The selected size and shape of the zinc and porogen particles influence the morphology of the pore structure. A limitation is that resulting sponges have disordered pore structures that result in low mechanical strength at low volume fractions of zinc (&#60;30%). Applications for these zinc-sponge electrodes include batteries for grid-storage, personal electronics, electric vehicles, and electric aviation. Users can expect zinc-sponge electrodes to cycle up to 40% depth of discharge at technologically relevant rates and areal capacities without the formation of separator-piercing dendrites.

The goal of the reported protocols is to create rechargeable zinc-sponge electrodes that suppress dendrites and shape change in zinc batteries, such as nickel&#8211;zinc or zinc&#8211;air.

Electrodos de batería de esponja de zinc que suprimen las dendritas

We report two methods to create zinc-sponge electrodes that suppress dendrite formation and shape change for rechargeable zinc batteries. Both methods are ...