Le financement de cette recherche a été assuré en partie par le Comité des cultures de matériel génétique USDA programme et associé de recherche de l&#39;USDA-ARS.

Une. Détermination de la pomme de terre amylose Tuber amidon <ol><li> Peler et couper les tubercules frais en petits cubes. </li><li> Placez les cubes de pommes de terre dans de petits sacs bruns et stocker pendant une nuit à -80 ° C. </li><li> Transfert cubes de pommes de terre dans des sacs de nylon et de lyophilisation. </li><li> Après lyophilisé, broyer l&#39;échantillon de pommes de terre en poudre en utilisant un mortier et un pilon ou un broyeur Wiley. </li><li> Dans un tube de 50 ml, ajouter 20 à 30 mg de l&#39;échantillon de sol tubercule lyophilisée. </li><li> Préparer une solution de 45% (p / v) d&#39;acide perchlorique (mélange 24,4 ml d&#39;acide perchlorique à 60% et 25,6 ml d&#39;eau ultra-pure. </li><li> Ajouter 500 ul de 45% (p / v) d&#39;acide perchlorique et secouer ou agiter pour disperser les granules d&#39;amidon. </li><li> Après une période d&#39;incubation de quatre minutes à la température ambiante, ajouter 16 ml d&#39;eau ultra-pure à la solution et mélanger au vortex. </li><li> Après matériau non soluble a déposé au fond du tube (7-10 min plus tard), transférer 40 pi de la solution sur une plaque de microtitration (éviter le pipetage de toutes les particules). </li><li> Ajouter 50 ul de solution d&#39;iode (KI à 2 g + 1 g d&#39;I2 dans 900 ml d&#39;eau ultra-pure) et mélanger l&#39;échantillon par pipettage. </li><li> Lire l&#39;absorbance à 550 nm et 620 nm immédiatement. </li><li> Déterminer le pourcentage d&#39;amylose après comparaison du rapport amylose / amylopectine de chaque échantillon (620 nm/550 nm l&#39;absorbance) avec une courbe standard générée à partir de solutions d&#39;amylose et d&#39;amylopectine dans une gamme de concentrations. Cette procédure sera maintenant décrit. Lire l&#39;ébauche (solution d&#39;iode et de l&#39;acide perchlorique) en même temps que les échantillons d&#39;essai. Utilisation blanchi données pour les analyses. </li></ol> 2. Amylose / amylopectine Curve <ol><li> Dans des tubes séparés pèsent 12,5 mg de l&#39;amylose et de l&#39;amylopectine 12,5 mg. </li><li> Ajouter à chaque tube 5 ml de 45% (p / v) d&#39;acide perchlorique et se dissoudre complètement. </li><li> Pour chacune des solutions (amylose et amylopectine), amener à un volume final de 50 ml avec de l&#39;eau ultra-pure. </li><li> Mélanger 6,25ml de stock amylose de l&#39;étape précédente avec 18,75 ml d&#39;eau ultra-pure. Cela fera une solution d&#39;amylose 6,25 mg / ml. </li><li> Répétez la procédure pour la solution de l&#39;amylopectine. </li><li> Utilisation de l&#39;amylose et des solutions standard de l&#39;amylopectine à partir des étapes 2,4 et 2,5, préparer des normes de teneur en amylose de 0 à 100 pour cent qui sont des% d&#39;amylose (100-0% d&#39;amylopectine) à un volume final de 5 ml pour créer la courbe d&#39;étalonnage à des intervalles de 10%. Par exemple, pour préparer: L&#39;amylose / 100% d&#39;amylopectine-type de 0%, une pipette 5 ml de solution d&#39;amylopectine. L&#39;amylose / 90% d&#39;amylopectine norme de 10%, mélanger 0,5 ml 4,5 ml d&#39;amylose et d&#39;amylopectine solutions. L&#39;amylose / 80% d&#39;amylopectine norme de 20%, mélanger 1,0 ml 4,0 ml d&#39;amylose et d&#39;amylopectine solutions. L&#39;amylose / 70% de la norme de 30% d&#39;amylopectine, de l&#39;amylose combiner 1,5 ml et 3,5 ml des solutions d&#39;amylopectine. L&#39;amylose / 60% de la norme de 40% d&#39;amylopectine, de l&#39;amylose combiner 2,0 ml et 2,0 ml des solutions d&#39;amylopectine. Le 50% d&#39;amylose/ 50% d&#39;amylopectine norme, mélanger 2,5 ml 2,5 ml d&#39;amylose et d&#39;amylopectine solutions. L&#39;amylose / 40% de la norme de 60% d&#39;amylopectine, de l&#39;amylose combiner 3,0 ml et 2,0 ml d&#39;amylopectine, et ainsi de suite). </li><li> Transférer 40 pl de chaque mélange standard à une plaque de microtitration. Inclure un puits avec 40 ul de 45% (p / v) d&#39;acide perchlorique le vide. </li><li> Ajouter 50 ul de solution d&#39;iode (KI à 2 g + 1 g d&#39;I2 dans 900 ml d&#39;eau ultra-pure) et mélanger chacun des échantillons (y compris le blanc) par pipetage. </li><li> Lire les absorbances à 550 nm et 620 nm immédiatement et calculer le rapport amylose / amylopectine pour chaque concentration. </li></ol>

<ol>
	<li>Composition Hoover, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=molecular+structure,+and+physicochemical+properties+of+tuber+and+root+starches:+a+review.">molecular structure, and physicochemical properties of tuber and root starches: a review.</a> Carbohydr. 45 (3), 253-267 (2001).</li><li>Bertoft, E., Blennow, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+Potato+Starch.">Structure of Potato Starch.</a> Advances in Potato Chemistry and Technology. , 83-98 (2009).</li><li>Campbell, M. R., Yeager, H., Abdubek, N., Pollak, L., Glover, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+methods+for+amylose+screening+in+maize+starches+from+exotic+backgrounds.">Comparison of methods for amylose screening in maize starches from exotic backgrounds.</a> Cereal Chem. 79, 317-321 (2002).</li><li>Zhu, T., Jackson, D. S., Wehling, R. L., Geera, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+amylose+determination+methods+and+the+development+of+a+dual+wavelength+iodine+binding+technique.">Comparison of amylose determination methods and the development of a dual wavelength iodine binding technique.</a> Cereal Chem. 85, 51-58 (2008).</li><li>Hovenkamp-Hermelink, J., Devries, J., Adamse, P., Jacobsen, E., Witholt, B., Feenstra, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+estimation+of+the+amylose+amylopectin+ratio+in+small+amounts+of+tuber+and+leaf+tissue+of+the+potato.">Rapid estimation of the amylose amylopectin ratio in small amounts of tuber and leaf tissue of the potato.</a> Potato Res. 31, 241-246 (1988).</li><li>Shannon, J. C., Garwood, D. L., Boyer, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics+and+Physiology+of+Starch+Development.">Genetics and Physiology of Starch Development.</a> Starch. , 23-82 (2009).</li><li>Haase, N. U., Plate, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+potato+starch+in+relation+to+varieties+and+environmental+factors.">Properties of potato starch in relation to varieties and environmental factors.</a> St&#228;rke. 48 (5), 167-171 (1996).</li><li>Johnston, F. B., Urbas, B., Khanzada, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+storage+on+the+size+distribution+and+amylose/amylopectin+ratio+in+potato+starch+granules.">Effect of storage on the size distribution and amylose/amylopectin ratio in potato starch granules.</a> Am. Pot. J. 45, 315-321 (1968).</li><li>Gibson, T. S., Solah, V. A., McCleary, B. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+procedure+to+measure+amylose+in+cereal+starches+and+flours+with+concanavalin+A.">A procedure to measure amylose in cereal starches and flours with concanavalin A.</a> J. Cereal Sci. 25 (2), 111-119 (1997).</li><li>Sun, S., Matheson, N., Yun, S. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+amylose+content+of+starches+after+precipitation+of+amylopectin+by+concanavalin+A.">Estimation of amylose content of starches after precipitation of amylopectin by concanavalin A.</a> Starch. 42, 302-305 (1990).</li></ol>

Nous n&#39;avons rien à communiquer.

La teneur en amylose dans les tubercules de pomme de terre est généralement comprise entre 20-35% 7,8. Si la plupart des valeurs sont en dehors de cette gamme, tenir compte de ces erreurs possibles: 1) les données brutes ont été utilisés à la place des données masquées pour la construction de la courbe standard amylose / amylopectine; 2) les données brutes ont été utilisés à la place des données masquées pour la détermination de la teneur en amylose ratios / amylopectine à partir des échant...

Environ 80% du poids frais d&#39;un tubercule de pomme de terre est de l&#39;eau; la quasi-totalité de la matière sèche restante est l&#39;amidon 1. La plupart de l&#39;amidon (70%) est composé d&#39;amylopectine, tandis que le reste est de l&#39;amylose. Le rapport entre l&#39;amylose et l&#39;amylopectine est la propriété la plus importante influence sur les propriétés physiques de l&#39;amidon. L&#39;amylose est un alpha 1-4 chaîne linéaire de glucose, tandis que l&#39;amylopectine est un linéaire alpha 1-4 chaîne alpha 1-6 branches 2. Des méthodes telles que la liaison de l&#39;iode, calorimétrie différentielle à balayage (DSC), la Chromatographie d&#39;exclusion stérique haute performance (HPSEC) et les interactions de la concanavaline A a été développée pour la détermination de l&#39;amidon de différentes espèces de plantes cultivées 3,4. Chaque protocole exige des compétences et des équipements spéciaux, ce qui rend difficile à l&#39;échelle à quantifier de nombreux échantillons à la fois. La méthode que nous présentons ici est un protocole modifié à partir de Hovenkamp-Hermelink et al. 5, qui est une longueur d&#39;onde double liaison de l&#39;iodeméthode basée sur les granules d&#39;amidon colorés. Les avantages de ce procédé par rapport à d&#39;autres comprennent la détermination de la teneur en amylose de l&#39;amidon brut sans le purifier et l&#39;utilisation du système à double longueur d&#39;onde pour augmenter la précision de la méthode 4,6.

<table border="1">
<tbody>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td> Reagents</td>
 </tr>
 <tr>
 <td>Amylose </td>
 <td>Sigma</td>
 <td>859656</td>
 <td></td>
 </tr>
 <tr>
 <td>Amylopectin </td>
 <td>Sigma</td>
 <td>A8515</td>
 <td></td>
 </tr>
 <tr>
 <td>Perchloric Acid 60%</td>
 <td>Sigma</td>
 <td>311413</td>
 <td>Very hazardous to skin and eyes</td>
 </tr>
 <tr>
 <td>Iodine</td>
 <td>Sigma</td>
 <td>23214TD</td>
 <td></td>
 </tr>
 <tr>
 <td>Potassium iodide</td>
 <td>Sigma</td>
 <td>08625JE</td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>Equipment</td>
 </tr>
 <tr>
 <td>Plate Reader</td>
 <td>Bio Tek</td>
 <td>ELx800</td>
 <td></td>
 </tr>
 </tbody>
</table>

rapid high throughput amylose determination in freeze dried potato tuber samples

Ce protocole décrit un procédé colorimétrique haut à travers mettre qui repose sur la formation d&#39;un complexe entre l&#39;iode et les chaînes de molécules de glucose de l&#39;amidon. Iode forme des complexes avec les deux amylose et l&#39;amylopectine dans de longues chaînes. Après l&#39;addition d&#39;iode à un échantillon d&#39;amidon, l&#39;absorption maximale de l&#39;amylose et de l&#39;amylopectine se produit à 620 et 550 nm, respectivement. Le ratio amylose / amylopectine peut être estimé à partir du rapport des valeurs d&#39;absorbance 620 nm et 550 et en les comparant à une courbe standard dans laquelle les concentrations connues spécifiques sont tracées en fonction des valeurs d&#39;absorption. Ce débit élevé, méthode peu coûteuse est fiable et reproductible, permettant l&#39;évaluation des grandes populations de clones de pommes de terre.

La courbe d&#39;étalonnage construite à partir des données masquées de différentes solutions de concentration amylose / amylopectine montre ratios d&#39;absorbance approximatif allant de 0,7 à 1,6 (Tableau 1). Une ligne de tendance de régression linéaire à partir de ces données sont ensuite utilisées pour déduire la teneur en amylose dans lyophilisés échantillons de pommes de terre (figure 1). L&#39;environnement de production de l&#39;usine a ...

Watch this Scientific Journal Video about Rapid High Throughput Amylose Determination in Freeze Dried Potato Tuber Samples at JoVE.com

Rapid High Throughput Amylose Determination in Freeze Dried Potato Tuber Samples

Rapides à haut débit amylose Détermination dans lyophilisé échantillons de pommes de terre de tubercules

This protocol describes a high through put colorimetric method that relies on the formation of a complex between iodine and chains of glucose molecules in ...

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Research

JoVE Journal

Chemistry

13.8K vues.  University of Wisconsin - Madison.  Ce protocole décrit un procédé colorimétrique haut à travers mettre qui repose sur la formation d'un complexe entre l'iode et les chaînes de molécules de glucose de l'amidon. Iode forme des complexes avec les deux amylose et l'amylopectine dans de longues chaînes. Après l'addition d'iode à un échantillon d'amidon, l'absorption maximale de l'amylose et de l'amylopectine se produit à 620 et 550 nm, respectivement. Le rati...

Vidéo: Rapid High Throughput Amylose Determination in Freeze Dried Potato Tuber Samples

Rapid Colorimetric Assays to Qualitatively Distinguish RNA and DNA in Biomolecular Samples

Biochemical experimentation generally requires accurate knowledge, at an early stage, of the nucleic acid, protein, and other biomolecular components in potentially heterogeneous specimens. Nucleic acids can be detected via several established approaches, including analytical methods that are spectrophotometric (e.g., A260), fluorometric (e.g., binding of fluorescent dyes), or colorimetric (nucleoside-specific chromogenic chemical reactions).1 Though it cannot readily distinguish RNA from DNA, the A260/A280 ratio is commonly employed, as it offers a simple and rapid2 assessment of the relative content of nucleic acid, which absorbs predominantly near 260 nm and protein, which absorbs primarily near 280 nm. Ratios &lt; 0.8 are taken as indicative of 'pure' protein specimens, while pure nucleic acid (NA) is characterized by ratios &gt; 1.53.
However, there are scenarios in which the protein/NA content cannot be as clearly or reliably inferred from simple uv-vis spectrophotometric measurements. For instance, (i) samples may contain one or more proteins which are relatively devoid of the aromatic amino acids responsible for absorption at &asymp;280 nm (Trp, Tyr, Phe), as is the case with some small RNA-binding proteins, and (ii) samples can exhibit intermediate A260/A280 ratios (~0.8 &lt; ~1.5), where the protein/NA content is far less clear and may even reflect some high-affinity association between the protein and NA components. For such scenarios, we describe herein a suite of colorimetric assays to rapidly distinguish RNA, DNA, and reducing sugars in a potentially mixed sample of biomolecules. The methods rely on the differential sensitivity of pentoses and other carbohydrates to Benedict's, Bial's (orcinol), and Dische's (diphenylamine) reagents; the streamlined protocols can be completed in a matter of minutes, without any additional steps of having to isolate the components. The assays can be performed in parallel to differentiate between RNA and DNA, as well as indicate the presence of free reducing sugars such as glucose, fructose, and ribose (Figure 1).

A suite of colorimetric assays is described for rapidly distinguishing protein, RNA, DNA, and reducing sugars in potentially heterogeneous biomolecular samples.

Rapid tests colorimétriques de vue qualitatif Distinguer l&#39;ARN et de l&#39;ADN dans les échantillons biomoléculaires

Biochemical experimentation generally requires accurate knowledge, at an early stage, of the nucleic acid, protein, and other biomolecular components in ...

Recherche

Chimie

A High-throughput-compatible FRET-based Platform for Identification and Characterization of Botulinum Neurotoxin Light Chain Modulators

Botulinum neurotoxin (BoNT) is a potent and potentially lethal bacterial toxin that binds to host motor neurons, is internalized into the cell, and cleaves intracellular proteins that are essential for neurotransmitter release. BoNT is comprised of a heavy chain (HC), which mediates host cell binding and internalization, and a light chain (LC), which cleaves intracellular host proteins essential for acetylcholine release. While therapies that inhibit toxin binding/internalization have a small time window of administration, compounds that target intracellular LC activity have a much larger time window of administrations, particularly relevant given the extremely long half-life of the toxin. In recent years, small molecules have been heavily analyzed as potential LC inhibitors based on their increased cellular permeability relative to larger therapeutics (peptides, aptamers, etc.). Lead identification often involves high-throughput screening (HTS), where large libraries of small molecules are screened based on their ability to modulate therapeutic target function. Here we describe a FRET-based assay with a commercial BoNT/A LC substrate and recombinant LC that can be automated for HTS of potential BoNT inhibitors. Moreover, we describe a manual technique that can be used for follow-up secondary screening, or for comparing the potency of several candidate compounds.

The botulinum neurotoxin type A light chain (BoNT/A LC) is a metalloprotease that enters motor neurons, cleaves its substrate SNAP-25, and disrupts neurotransmission, thereby resulting in flaccid paralysis. Utilizing a high-throughput-compatible FRET-based assay, large libraries of small molecules can be screened for their impact on BoNT/A LC enzymatic activity.

Une plate-forme à base de FRET haut-débit compatible pour l&#39;identification et la caractérisation de la chaîne neurotoxine botulique de lumière modulateurs

Botulinum neurotoxin (BoNT) is a potent and potentially lethal bacterial toxin that binds to host motor neurons, is internalized into the cell, and ...

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular identity and function. Each of the seven PtdInsPs varies in their distribution and abundance, which are tightly regulated by specific kinases and phosphatases. The abundance of PtdInsPs can change abruptly in response to various signaling events or disturbance of the regulatory machinery. To understand how these events lead to changes in the amount of PtdInsPs and their resulting impact, it is important to quantify PtdInsP levels before and after a signaling event or between control and abnormal conditions. However, due to their low abundance and similarity, quantifying the relative amounts of each PtdInsP can be challenging. This article describes a method for quantifying PtdInsP levels by metabolically labeling cells with 3H-myo-inositol, which is incorporated into PtdInsPs. Phospholipids are then precipitated and deacylated. The resulting soluble 3H-glycero-inositides are further extracted, separated by high-performance liquid chromatography (HPLC), and detected by flow scintillation. The labeling and processing of yeast samples is described in detail, as well as the instrumental setup for the HPLC and flow scintillator. Despite losing structural information regarding acyl chain content, this method is sensitive and can be optimized to concurrently quantify all seven PtdInsPs in cells.

Phosphoinositides are signaling lipids whose relative abundance rapidly changes in response to various stimuli. This article describes a method to measure the abundance of phosphoinositides by metabolically labeling cells with 3H-myo-inositol, followed by extraction and deacylation. Extracted glycero-inositides are then separated by high-performance liquid chromatography and quantified by flow scintillation.

Radiomarquage et la quantification des niveaux cellulaires de phosphoinositides par chromatographie liquide haute performance couplée flux scintillation

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular ...

Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, and that these chemical fingerprints can be used for plant species identification. The mass spectral data can be acquired rapidly and in a high throughput manner without the need for sample extraction, derivatization or pH adjustment steps. The use of this technique bypasses challenges presented by more conventional techniques including lengthy chromatography analysis times and resource intensive methods. The high throughput capabilities of the direct analysis in real time-high resolution mass spectrometry protocol, coupled with multivariate statistical analysis processing of the data, provide not only class characterization of plants, but also yield species and varietal information. Here, the technique is demonstrated with two psychoactive plant products, Mitragyna speciosa (Kratom) and Datura (Jimsonweed), which were subjected to direct analysis in real time-high resolution mass spectrometry followed by statistical analysis processing of the mass spectral data. The application of these tools in tandem enabled the plant materials to be rapidly identified at the level of variety and species.

A method for species identification of botanical material by direct analysis in real time-high resolution mass spectrometry and multivariate statistical analysis is presented.

Rapid à haut débit Identification des espèces de matériel botanique Utilisation de l&#39;analyse directe en temps réel Résolution Spectrométrie de Masse Haute

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, ...

Extraction and Purification of Polyphenols from Freeze-dried Berry Powder for the Treatment of Vascular Smooth Muscle Cells In Vitro

Epidemiological studies indicate that increased flavonoid intake correlates with decreased mortality due to cardiovascular diseases (CVD) in the United States (US) and Europe. Berries are widely consumed in the US and have a high polyphenolic content. Polyphenols have been shown to interact with many molecular targets and to exert numerous positive biological functions, including antioxidant, anti-inflammatory, and cardioprotective effects. Polyphenols isolated from blackberry (BL), raspberry (RB), and black raspberry (BRB) reduce oxidative stress and cellular senescence in response to angiotensin II (Ang II). This work provides a detailed description of the protocol used to prepare the polyphenol extracts from freeze-dried berries. Polyphenol extractions from freeze-dried berry powder were performed using 80% aqueous ethanol and an ultrasonic-assisted extraction method. The crude extract was further purified and fractionated using chloroform and ethyl acetate, respectively. The effects of both crude and purified extracts were tested on Vascular Smooth Muscle Cells (VSMCs) in culture.

Extraction and Purification of Polyphenols from Freeze-dried Berry Powder for the Treatment of Vascular Smooth Muscle Cells In Vitro

This work details a step-by-step method to prepare polyphenol-rich extracts from freeze-dried berry powder. In addition, it provides a thorough description of how to use these polyphenol-rich extracts in cell culture in the presence of the peptide hormone angiotensin II (Ang II) using Vascular Smooth Muscle Cells (VSMCs).

Extraction et purification des polyphénols à partir de la poudre de baies lyophilisée pour le traitement des cellules musculaires lisses vasculaires<em&gt; In Vitro</em

Epidemiological studies indicate that increased flavonoid intake correlates with decreased mortality due to cardiovascular diseases (CVD) in the United ...

Disentangling High Strength Copolymer Aramid Fibers to Enable the Determination of Their Mechanical Properties

Traditionally, soft body armor has been made from poly(p-phenylene terephthalamide) (PPTA) and ultra-high molecular weight polyethylene. However, to diversify the fiber choices in the United States body armor market, copolymer fibers based on the combination of 5-amino-2-(p-aminophenyl) benzimidazole (PBIA) and the more conventional PPTA were introduced. Little is known regarding the long-term stability of these fibers, but as condensation polymers, they are expected to have potential sensitivity to moisture and humidity. Therefore, characterizing the strength of the materials and understanding their vulnerability to environmental conditions is important for evaluating their use lifetime in safety applications. Ballistic resistance and other critical structural properties of these fibers are predicated on their strength. To accurately determine the strength of the individual fibers, it is necessary to disentangle them from the yarn without introducing any damage. Three aramid-based copolymer fibers were selected for the study. The fibers were washed with acetone followed by methanol to remove an organic coating that held the individual fibers in each yarn bundle together. This coating makes it difficult to separate single fibers from the yarn bundle for mechanical testing without damaging the fibers and affecting their strength. After washing, fourier transform infrared (FTIR) spectroscopy was performed on both washed and unwashed samples and the results were compared. This experiment has shown that there are no significant variations in the spectra of poly(p-phenylene-benzimidazole-terephthalamide-co-p-phenylene terephthalamide) (PBIA-co-PPTA1) and PBIA-co-PPTA3 after washing, and only a small variation in intensity for PBIA. This indicates that the acetone and methanol rinses are not adversely affecting the fibers and causing chemical degradation. Additionally, single fiber tensile testing was performed on the washed fibers to characterize their initial tensile strength and strain to failure, and compare those to other reported values. Iterative procedural development was necessary to find a successful method for performing tensile testing on these fibers.

The primary goal of the study is to develop a protocol to prepare consistent specimens for accurate mechanical testing of high strength copolymer aramid fibers, by removing a coating and disentangling the individual fiber strands without introducing significant chemical or physical degradation.

Démêler les fibres d’aramide de copolymère haute résistance afin de permettre la détermination de leurs propriétés mécaniques

Traditionally, soft body armor has been made from poly(p-phenylene terephthalamide) (PPTA) and ultra-high molecular weight polyethylene. However, to ...

High-throughput and Comprehensive Drug Surveillance Using Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug crisis in public health. Conventional urine drug testing based on a two-tier immunoassay screen followed by a gas chromatography-tandem mass spectrometry (GC-MS/MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) method are expensive and prone to bias while being limited to targeted panels of known drugs of abuse (DoA). Herein, we outline an improved method for drug surveillance that allows for the resolution and detection of an expanded panel of DoA and their metabolites when using multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). Multiplexed separations of ten urine samples with a quality control by CE (&lt; 3 min/sample) in conjunction with full-scan data acquisition using a time-of-flight mass spectrometer (TOF-MS) under positive ion mode detection allows for the identification and quantification of DoA above recommended cut-off levels. An excellent resolution of drug isomers and isobars, including background interferences, are achieved when using MSI-CE-MS with an electrokinetic spacer between sample segments, where accurate mass/molecular formula together with the comigration of a matching deuterated internal standard and the detection of one or more bio-transformed metabolites facilitate DoA identification over a wider detection window. Additionally, urine samples can be analyzed directly without enzyme deconjugation for the rapid screening without complicated sample workup. MSI-CE-MS enables the surveillance of a broad spectrum of DoA that is required for the treatment monitoring of high-risk patients, including confirming prescribed drug adherence, revealing illicit drug use/substitution, and evaluating optimal dosage regimes as required for new advances in precision medicine.

Here we describe a high-throughput method for comprehensive drug surveillance that allows for the improved resolution and detection of large panels of drugs of abuse and their metabolites, with quality control based on multisegment injection-capillary electrophoresis-mass spectrometry.

Surveillance des médicaments haut débit et complet à l’aide de la spectrométrie de masse de l’électrophorèse capillaire-Injection Multisegment

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug ...

Biological Samples Preparation for Speciation at Cryogenic Temperature using High-Resolution  X-Ray Absorption Spectroscopy

The study of elements with X-ray absorption spectroscopy (XAS) is of particular interest when studying the role of metals in biological systems. Sample preparation is a key and often complex procedure, particularly for biological samples. Although X-ray speciation techniques are widely used, no detailed protocol has been yet disseminated for users of the technique. Further, chemical state modification is of concern, and cryo-based techniques are recommended to analyze the biological samples in their near-native hydrated state to provide the maximum preservation of chemical integrity of the cells or tissues. Here, we propose a cellular preparation protocol based on cryo-preserved samples. It is demonstrated in a high energy resolution fluorescence detected X-ray absorption spectroscopy study of selenium in cancer cells and a study of iron in phytoplankton. This protocol can be used with other biological samples and other X-ray techniques that can be damaged by irradiation.

This protocol presents a detailed procedure to prepare biological cryosamples for synchrotron-based X-ray absorption spectroscopy experiments. We describe all the steps required to optimize sample preparation and cryopreservation with examples of the protocol with cancer and phytoplankton cells. This method provides a universal standard of sample cryo-preparation.

Préparation d’échantillons biologiques pour la spéciation à température cryogénique à l’aide de la spectroscopie d’absorption de rayons X à haute résolution

The study of elements with X-ray absorption spectroscopy (XAS) is of particular interest when studying the role of metals in biological systems. Sample ...

An Externally-Heated Diamond Anvil Cell for Synthesis and Single-Crystal Elasticity Determination of Ice-VII at High Pressure-Temperature Conditions

The externally-heated diamond anvil cell (EHDAC) can be used to generate simultaneously high-pressure and high-temperature conditions found in Earth&#8217;s and planetary interiors. Here we describe the design and fabrication of the EHDAC assemblies and accessories, including ring resistive heaters, thermal and electrical insulating layers, thermocouple placement, as well as the experimental protocol for preparing the EHDAC using these parts. The EHDAC can be routinely used to generate megabar pressures and up to 900 K temperatures in open air, and potentially higher temperatures up to ~1200 K with a protective atmosphere (i.e., Ar mixed with 1% H2). Compared with a laser-heating method for reaching temperatures typically &#62;1100 K, external heating can be easily implemented and provide a more stable temperature at &#8804;900 K and less temperature gradients to the sample. We showcased the application of the EHDAC for synthesis of single crystal ice-VII and studied its single-crystal elastic properties using synchrotron-based X-ray diffraction and Brillouin scattering at simultaneously high-pressure high-temperature conditions.

This work focuses on the standard protocol for preparing the externally-heated diamond anvil cell (EHDAC) for generating high-pressure and high-temperature (HPHT) conditions. The EHDAC is employed to investigate materials in Earth and planetary interiors under extreme conditions, which can be also used in solid state physics and chemistry studies.

Une cellule d’enclume de diamant chauffée extérieurement pour la synthèse et la détermination d’élasticité d’un cristal unique de glace-VII aux conditions de haute pression-température

The externally-heated diamond anvil cell (EHDAC) can be used to generate simultaneously high-pressure and high-temperature conditions found in ...

Synthèse et découverte de MOF à base de phosphonates : une approche solvothermique

Discovery and Synthesis Optimization of Isoreticular Al(III) Phosphonate-Based Metal-Organic Framework Compounds Using High-Throughput Methods

High-throughput (HT) methods are an important tool for the fast and efficient screening of synthesis parameters and the discovery of new materials. This manuscript describes the synthesis of metal-organic frameworks (MOFs) from solution using an HT reactor system, resulting in the discovery of various phosphonate-based MOFs of the composition [Al2H12-x(PMP)3]Clx&#8729;6H2O (H4PMP = N,N &#39;-piperazine bis(methylenephosphonic acid)) for x = 4, 6, denoted as Al-CAU-60-xHCl, containing trivalent aluminum ions. This was accomplished under solvothermal reaction conditions by systematically screening the impact of the molar ratio of the linker to the metal and the pH of the reaction mixture on the product formation. The protocol for the HT investigation includes six steps: a) synthesis planning (DOE = design of&#160;experiment) within the HT methodology, b) dosing and working with in-house developed HT reactors, c) solvothermal synthesis, d) synthesis workup using in-house developed filtration blocks, e) characterization by HT powder X-ray diffraction, and f) evaluation of the data. The HT methodology was first used to study the influence of acidity on the product formation, leading to the discovery of Al-CAU-60&#8729;xHCl (x = 4 or 6).

Pleins feux sur l’auteur : Accélérer les découvertes en chimie des matériaux microporeux 

The targeted synthesis of new metal-organic frameworks (MOFs) is difficult, and their discovery depends on the knowledge and creativity of the chemist. High-throughput methods allow complex synthetic parameter fields to be explored quickly and efficiently, accelerating the process of finding crystalline compounds and identifying synthetic and structural trends.

Découverte et optimisation de la synthèse de composés de cadre organométallique à base d’Al(III) phosphonate isoréticulaire à l’aide de méthodes à haut débit

High-throughput (HT) methods are an important tool for the fast and efficient screening of synthesis parameters and the discovery of new materials. This ...