Selective Capture (selective + capture)

Distribution by Scientific Domains

Selected Abstracts

Selective Capture of Water Using Microporous Adsorbents To Increase the Lifetime of Lubricants

Eng-Poh Ng
Abstract Long live lubricants: The selective capture of water from lubricants using nanosized microporous aluminophosphate (AEI) and aluminosilicate materials was studied. Nearly 98,% of the moisture was removed from the lubricating oil under ambient conditions, resulting in a significant improvement in the lubricating service lifetime. Moreover, both the lubricant and the microporous sorbents can be recovered and reused. The selective capture of water from lubricants using nanosized microporous aluminophosphate and aluminosilicate materials was studied with an aim to increase the lifetime of the lubricating mineral oil. The amount of water present in oxidized lubricating oil before and after treatment with microporous materials was studied by FTIR spectroscopy and determined quantitatively using the Karl Fischer titration method. Nanosized aluminophosphate revealed a high selectivity for water without adsorbing other additives, in contrast to nanosized aluminosilicates which also adsorb polar oxidation products and ionic additives. About 98,% of the initial moisture could be removed from the lubricating oil under ambient conditions, resulting in a significant improvement in the lubricating service lifetime. Moreover, no by-products are formed during the process and both the lubricant and the sorbents can be recovered and reused, thus the method is environmentally friendly. [source]

Precautions to improve the accuracy of quantitative determinations of biomarkers in clinical diagnostics

Nasim Ghasemzadeh
Abstract Although protein biomarkers have a great potential as biomarkers for diagnosis of diseases, they are seldom used in hospitals. There are many reasons for this, for instance, the difficulties to (i) find a biomarker for which the concentration in body fluids clearly differs between patients and healthy subjects, (ii) attain purification of the biomarker close to 100%, which is required for production of conventional protein antibodies as well as artificial gel antibodies for selective capture of a biomarker, (iii) design a standard curve for rapid and accurate determination of the concentration of the biomarker in the body fluid because of adsorption of the biomarker onto vials, pipettes, etc., (iv) determine accurately the sample volume delivered by a pipette, (v) avoid polymerization of the biomarker upon storage and to decide whether it is in the form not only of monomers, but also of dimers, trimers, etc., in the native state, (vi) determine the degree of possible glycosylation and amidation of the biomarker and (vii) decide whether glycosylation and amidation positively or negatively affects the possibilit to use the protein as a biomarker. In this article, we discuss in quantitative terms the difficulties (iii,vii) and how to overcome them, which also may help to overcome the difficulty (ii), which in turn minimizes difficulty (i). [source]

An improved, simple nest-box trap

Scott L. Friedman
ABSTRACT The success of ornithological studies often hinges on a researcher's ability to capture individuals quickly and efficiently. Sometimes it is necessary to capture the same individual multiple times, as is the case in many metabolic, ecotoxicological, and immunocompetence studies. Several methods of capturing cavity-nesting birds at their nest boxes have been described. However, these methods proved inefficient when attempting to catch wary individuals that had already been captured previously. Here we describe a simple and inexpensive method for capturing cavity-nesting birds using a square plate of sheet metal (5.8 × 5.8 × 0.2 cm), a drinking straw, a piece of duct tape, and a monofilament line. This method has the advantages of allowing selective capture of one, but not both members of a pair and being nearly invisible to trap-shy birds. SINOPSIS El éxito de estudios ornitológicos está atado, muchas veces, a la habilidad del investigador para atrapar aves de forma rápida y eficiente. En ocasiones es necesario capturar el mismo individuo multiples veces, como es en el caso de estudios metabólicos, ecotoxicológicos o de inmunocompetencia. Se han descrito varios métodos para atrapar aves que anidan en cajas. Sin embargo, estos métodos han provado ser ineficientes cuando se intenta capturar aves que han sido alertadas por haberse capturado anteriormente. Describimos un método, simple y de bajo costo, para capturar aves que anidan en cajas, utilizando una plancha cuadrada de metal (5.8 × 5.8 × 0.2 cm), un sorbeto y un pedazo de cinta adhesiva plástica (duck tape) y un monofilamento. Este método tiene ventajas, y permite la captura selectiva de uno de los miembros de la pareja. El mismo es virtualmente invisible para las aves. [source]

Water-elutability of nucleic acids from metal-chelate affinity adsorbents: enhancement by control of surface charge density,

Joseph Y. Fu
Abstract Immobilized metal affinity chromatography (IMAC) is widely used for purification of proteins, especially "hexahistidine-tagged" recombinant proteins. We previously demonstrated the application of IMAC to selective capture of nucleic acids, including RNA, selectively-denatured genomic DNA, and PCR primers through interactions with purine bases exposed in single-stranded regions. We also found that the binding affinity of nucleic acids for IMAC adsorbents can be increased several-fold by addition of 20 volume% of neutral additives such as ethanol or DMSO. In the present work, it is demonstrated that bound nucleic acids can be effectively eluted with water instead of the usual imidazole-containing competitive eluants, when the surface density of negative charges is enhanced by operation at alkaline pH, or by deliberate metal-underloading of the anionic chelating ligands. With enhanced negative surface charge density, nucleic acid adsorption can be made strongly dependent on the presence of adsorption-promoting additives and/or repulsion-shielding salts, and removal of these induces elution. Complete water-elutability is demonstrated for baker's yeast RNA bound to 10% Cu(II)- underloaded IDA Chelating Sepharose in a binding buffer of 20,mM HEPES, 240,mM NaCl, pH,7. Water elutability will significantly enhance the utility of IMAC in nucleic acid separations. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Prevalence of Escherichia coli O157:H7 in industrial minced beef

C. Vernozy-Rozand
Aims: ,The lack of baseline data on the prevalence of Escherichia coli O157:H7 in retail minced beef in France prompted this survey of industrial minced beef production. Methods and Results: ,An automated enzyme-linked fluorescence immunoassay (ELFA), the VIDAS E. coli O157 method, was used to detect E. coli O157 in industrial minced beef samples. Confirmation of samples positive according to the ELFA was performed using an automated immunoconcentration (ICE) system, VIDAS ICE, which allows the selective capture and release of target organisms. The ICE was followed by culture on cefixime tellurite sorbitol MacConkey agar and a chromogenic medium, O157:H7 ID. Of the 3450 minced beef samples tested, 175 samples were positive with the ELFA method and, of these, four were confirmed by the ICE method. They were identified as sorbitol-negative, O157-positive, H7-positive, mobile, verotoxin-producing E. coli . Conclusions: ,The prevalence of E. coli O157:H7 in industrial French minced beef was 0·12%, consistent with many other reports. Significance and Impact of the Study: ,The low infective dose of E. coli O157:H7 presents a major threat. The main means of combating this organism are thermal destruction and good food hygiene covering activities on-farm, in the abattoir and in minced beef industries. [source]

Highly avid magnetic bead capture: An efficient selection method for de novo protein engineering utilizing yeast surface display

Margaret Ackerman
Abstract Protein engineering relies on the selective capture of members of a protein library with desired properties. Yeast surface display technology routinely enables as much as million-fold improvements in binding affinity by alternating rounds of diversification and flow cytometry-based selection. However, flow cytometry is not well suited for isolating de novo binding clones from naïve libraries due to limitations in the size of the population that can be analyzed, the minimum binding affinity of clones that can be reliably captured, the amount of target antigen required, and the likelihood of capturing artifactual binders to the reagents. Here, we demonstrate a method for capturing rare clones that maintains the advantages of yeast as the expression host, while avoiding the disadvantages of FACS in isolating de novo binders from naïve libraries. The multivalency of yeast surface display is intentionally coupled with multivalent target presentation on magnetic beads,allowing isolation of extremely weak binders from billions of non-binding clones, and requiring far less target antigen for each selection, while minimizing the likelihood of isolating undesirable alternative solutions to the selective pressure. Multivalent surface selection allows 30,000-fold enrichment and almost quantitative capture of micromolar binders in a single pass using less than one microgram of target antigen. We further validate the robust nature of this selection method by isolation of de novo binders against lysozyme as well as its utility in negative selections by isolating binders to streptavidin-biotin that do not cross-react to streptavidin alone. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]