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Artikel ; Online: Spiral Countercurrent Chromatography Enrichment, Characterization, and Assays of Carbon Nanotube Chiralities for Use in Biosensors

Steingrimur Stefansson / Rodrigo Lazo-Portugal / Saeyoung Ahn / Martha Knight

ACS Omega, Vol 2, Iss 3, Pp 1156-

2017 Band 1162

Schlagwörter	Chemistry ; QD1-999
Sprache	Englisch
Erscheinungsdatum	2017-03-01T00:00:00Z
Verlag	American Chemical Society
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel: Spiral Countercurrent Chromatography Enrichment, Characterization, and Assays of Carbon Nanotube Chiralities for Use in Biosensors.

Stefansson, Steingrimur / Lazo-Portugal, Rodrigo / Ahn, Saeyoung / Knight, Martha

ACS omega

2017 Band 2, Heft 3, Seite(n) 1156–1162

Abstract: Single-walled carbon nanotubes (SWCNTs) are synthetic materials that hold great promise for electronics that are smaller and more versatile than the current silica-based technologies. But as-produced SWCNTs are generally a mixture of nanotubes with ... ...

Abstract	Single-walled carbon nanotubes (SWCNTs) are synthetic materials that hold great promise for electronics that are smaller and more versatile than the current silica-based technologies. But as-produced SWCNTs are generally a mixture of nanotubes with different structures that have vastly different properties. Separating these SWCNTs from multiwalled and metallic carbon nanotubes is vital to explore their individual properties and commercial utility ranging from optics to semiconductors. Compounding the problem of commercial investigation is that the semiconducting SWCNTs are also a mixture of different diameters and/or chiralities with different properties. Analyzing properties of enriched semiconducting SWCNT chiralities has only recently been possible through separation techniques such as aqueous two-phase solvent systems. Our study illustrates a semipreparative spiral countercurrent chromatography (CCC) separation of a commercial mixture of SWCNTs into distinct enriched fractions. A new mixer-settler spiral disk rotor was applied in this study, in which we compare the enriched SWCNTs for their effectiveness in biosensors with a high-throughput model assay, followed by antibody-mediated detection of
Sprache	Englisch
Erscheinungsdatum	2017-03-24
Erscheinungsland	United States
Dokumenttyp	Journal Article
ISSN	2470-1343
ISSN	2470-1343
DOI	10.1021/acsomega.6b00536
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Isolation of Low Abundance Proteins and Cells Using Buoyant Glass Microbubble Chromatography

Cha-Mei Tang / Daniel L. Adams / Steingrimur Stefansson

Chromatography Research International, Vol

2013 Band 2013

Schlagwörter	Analytical chemistry ; QD71-142 ; Chemistry ; QD1-999 ; Science ; Q ; DOAJ:Analytical Chemistry ; DOAJ:Chemistry
Sprache	Englisch
Erscheinungsdatum	2013-01-01T00:00:00Z
Verlag	Hindawi Publishing Corporation
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Purification of semiconducting single-walled carbon nanotubes by spiral counter-current chromatography.

Knight, Martha / Lazo-Portugal, Rodrigo / Ahn, Saeyoung Nate / Stefansson, Steingrimur

Journal of chromatography. A

2017 Band 1483, Seite(n) 93–100

Abstract: Over the last decade man-made carbon nanostructures have shown great promise in electronic applications, but they are produced as very heterogeneous mixtures with different properties so the achievement of a significant commercial application has been ... ...

Abstract	Over the last decade man-made carbon nanostructures have shown great promise in electronic applications, but they are produced as very heterogeneous mixtures with different properties so the achievement of a significant commercial application has been elusive. The dimensions of single-wall carbon nanotubes are generally a nanometer wide, up to hundreds of microns long and the carbon nanotubes have anisotropic structures. They are processed to have shorter lengths but they need to be sorted by diameter and chirality. Thus counter-current chromatography methods developed for large molecules are applied to separate these compounds. A modified mixer-settler spiral CCC rotor made with 3 D printed disks was used with a polyethylene glycol-dextran 2-phase solvent system and a surfactant gradient to purify the major species in a commercial preparation. We isolated the semi-conducting single walled carbon nanotube chiral species identified by UV spectral analysis. The further development of spiral counter-current chromatography instrumentation and methods will enable the scalable purification of carbon nanotubes useful for the next generation electronics.
Mesh-Begriff(e)	Biosensing Techniques ; Color ; Countercurrent Distribution/instrumentation ; Countercurrent Distribution/methods ; Nanotechnology ; Nanotubes, Carbon/chemistry ; Powders ; Semiconductors ; Solutions ; Solvents/chemistry
Chemische Substanzen	Nanotubes, Carbon ; Powders ; Solutions ; Solvents
Sprache	Englisch
Erscheinungsdatum	2017-02-03
Erscheinungsland	Netherlands
Dokumenttyp	Journal Article
ZDB-ID	1171488-8
ISSN	1873-3778 ; 0021-9673
ISSN (online)	1873-3778
ISSN	0021-9673
DOI	10.1016/j.chroma.2016.12.070
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Purification of semiconducting single-walled carbon nanotubes by spiral counter-current chromatography

Knight, Martha / Rodrigo Lazo-Portugal / Saeyoung Nate Ahn / Steingrimur Stefansson

Journal of chromatography. 2017 Feb. 03, v. 1483

2017

Abstract	Over the last decade man-made carbon nanostructures have shown great promise in electronic applications, but they are produced as very heterogeneous mixtures with different properties so the achievement of a significant commercial application has been elusive. The dimensions of single-wall carbon nanotubes are generally a nanometer wide, up to hundreds of microns long and the carbon nanotubes have anisotropic structures. They are processed to have shorter lengths but they need to be sorted by diameter and chirality. Thus counter-current chromatography methods developed for large molecules are applied to separate these compounds. A modified mixer-settler spiral CCC rotor made with 3 D printed disks was used with a polyethylene glycol-dextran 2-phase solvent system and a surfactant gradient to purify the major species in a commercial preparation. We isolated the semi-conducting single walled carbon nanotube chiral species identified by UV spectral analysis. The further development of spiral counter-current chromatography instrumentation and methods will enable the scalable purification of carbon nanotubes useful for the next generation electronics.
Schlagwörter	carbon ; carbon nanotubes ; countercurrent chromatography ; electronics ; instrumentation ; polyethylene ; solvents ; spectral analysis ; stereoisomerism ; surfactants
Sprache	Englisch
Erscheinungsverlauf	2017-0203
Umfang	p. 93-100.
Erscheinungsort	Elsevier B.V.
Dokumenttyp	Artikel
ZDB-ID	218139-3
ISSN	0021-9673 ; 0378-4355 ; 0376-737X
ISSN	0021-9673 ; 0378-4355 ; 0376-737X
DOI	10.1016/j.chroma.2016.12.070
Datenquelle	NAL Katalog (AGRICOLA)

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Artikel ; Online: Common benzothiazole and benzoxazole fluorescent DNA intercalators for studying Alzheimer Aβ1-42 and prion amyloid peptides

Steingrimur Stefansson / Daniel L Adams / Cha-Mei Tang

BioTechniques, Vol 52, Iss 5, Pp 1-

2012 Band 6

Abstract: Amyloids are fibrillar protein aggregates associated with a number of neurodegenerative pathologies including Alzheimer and Creutzfeldt—Jakob disease. The study of amyloids is usually based on fluorescence with the dye thioflavin-T. Although a number of ... ...

Abstract	Amyloids are fibrillar protein aggregates associated with a number of neurodegenerative pathologies including Alzheimer and Creutzfeldt—Jakob disease. The study of amyloids is usually based on fluorescence with the dye thioflavin-T. Although a number of amyloid binding compounds have been synthesized, many are nonfluorescent or not readily available for research use. Here we report on a class of commercial benzothiazole/benzoxazole containing fluorescent DNA intercalators from Invitrogen that possess the ability to bind amyloid Aβ1-42 peptide and hamster prion. These dyes fluoresce from 500–750 nm and are available as dimers or monomers. We demonstrate that these dyes can be used as acceptors for thioflavin-T fluorescence resonance energy transfer as well as reporter groups for binding studies with Congo red and chrysamine G. As more potential therapeutic compounds for these diseases are generated, there is a need for simple and inexpensive methods to monitor their interactions with amyloids. The fluorescent dyes reported here are readily available and can be used as tools for biochemical studies of amyloid structures and in vitro screening of potential therapeutics.
Schlagwörter	Alzheimer ; amyloid ; thioflavin ; chrysamine ; benzothiazole ; Congo red ; Biology (General) ; QH301-705.5
Thema/Rubrik (Code)	540
Sprache	Englisch
Erscheinungsdatum	2012-05-01T00:00:00Z
Verlag	Future Science Ltd
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Multi-Phenotypic subtyping of circulating tumor cells using sequential fluorescent quenching and restaining.

Adams, Daniel L / Alpaugh, R Katherine / Tsai, Susan / Tang, Cha-Mei / Stefansson, Steingrimur

Scientific reports

2016 Band 6, Seite(n) 33488

Abstract: In tissue biopsies formalin fixed paraffin embedded cancer blocks are micro-sectioned producing multiple semi-identical specimens which are analyzed and subtyped proteomically, and genomically, with numerous biomarkers. In blood based biopsies (BBBs), ... ...

Abstract	In tissue biopsies formalin fixed paraffin embedded cancer blocks are micro-sectioned producing multiple semi-identical specimens which are analyzed and subtyped proteomically, and genomically, with numerous biomarkers. In blood based biopsies (BBBs), blood is purified for circulating tumor cells (CTCs) and clinical utility is typically limited to cell enumeration, as only 2-3 positive fluorescent markers and 1 negative marker can be used. As such, increasing the number of subtyping biomarkers on each individual CTC could dramatically enhance the clinical utility of BBBs, allowing in depth interrogation of clinically relevant CTCs. We describe a simple and inexpensive method for quenching the specific fluors of fluorescently stained CTCs followed by sequential restaining with additional biomarkers. As proof of principle a CTC panel, immunosuppression panel and stem cell panel were used to sequentially subtype individual fluorescently stained patient CTCs, suggesting a simple and universal technique to analyze multiple clinically applicable immunomarkers from BBBs.
Mesh-Begriff(e)	Cell Line, Tumor ; Drug Evaluation, Preclinical ; Epithelial-Mesenchymal Transition ; Fluorescence ; Humans ; Neoplastic Cells, Circulating/classification ; Neoplastic Cells, Circulating/pathology ; Staining and Labeling
Sprache	Englisch
Erscheinungsdatum	2016-09-20
Erscheinungsland	England
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/srep33488
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: A cell transportation solution that preserves live circulating tumor cells in patient blood samples.

Stefansson, Steingrimur / Adams, Daniel L / Ershler, William B / Le, Huyen / Ho, David H

BMC cancer

2016 Band 16, Seite(n) 300

Abstract: Background: Circulating tumor cells (CTCs) are typically collected into CellSave fixative tubes, which kills the cells, but preserves their morphology. Currently, the clinical utility of CTCs is mostly limited to their enumeration. More detailed ... ...

Abstract	Background: Circulating tumor cells (CTCs) are typically collected into CellSave fixative tubes, which kills the cells, but preserves their morphology. Currently, the clinical utility of CTCs is mostly limited to their enumeration. More detailed investigation of CTC biology can be performed on live cells, but obtaining live CTCs is technically challenging, requiring blood collection into biocompatible solutions and rapid isolation which limits transportation options. To overcome the instability of CTCs, we formulated a sugar based cell transportation solution (SBTS) that stabilizes cell viability at ambient temperature. In this study we examined the long term viability of human cancer cell lines, primary cells and CTCs in human blood samples in the SBTS for transportation purposes. Methods: Four cell lines, 5 primary human cells and purified human PBMCs were tested to determine the viability of cells stored in the transportation solution at ambient temperature for up to 7 days. We then demonstrated viability of MCF-7 cells spiked into normal blood with SBTS and stored for up to 7 days. A pilot study was then run on blood samples from 3 patients with metastatic malignancies stored with or without SBTS for 6 days. CTCs were then purified by Ficoll separation/microfilter isolation and identified using CTC markers. Cell viability was assessed using trypan blue or CellTracker™ live cell stain. Results: Our results suggest that primary/immortalized cell lines stored in SBTS remain ~90% viable for > 72 h. Further, MCF-7 cells spiked into whole blood remain viable when stored with SBTS for up to 7 days. Finally, live CTCs were isolated from cancer patient blood samples kept in SBTS at ambient temperature for 6 days. No CTCs were isolated from blood samples stored without SBTS. Conclusions: In this proof of principle pilot study we show that viability of cell lines is preserved for days using SBTS. Further, this solution can be used to store patient derived blood samples for eventual isolation of viable CTCs after days of storage. Therefore, we suggest an effective and economical transportation of cancer patient blood samples containing live CTCs can be achieved.
Mesh-Begriff(e)	Blood Cells/drug effects ; Cell Count ; Cell Survival/drug effects ; Female ; Humans ; MCF-7 Cells ; Male ; Neoplastic Cells, Circulating/drug effects ; Neoplastic Cells, Circulating/pathology ; Solutions/pharmacology ; Specimen Handling/methods ; Transportation
Chemische Substanzen	Solutions
Sprache	Englisch
Erscheinungsdatum	2016-05-06
Erscheinungsland	England
Dokumenttyp	Journal Article
ISSN	1471-2407
ISSN (online)	1471-2407
DOI	10.1186/s12885-016-2330-1
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Common benzothiazole and benzoxazole fluorescent DNA intercalators for studying Alzheimer Aβ1-42 and prion amyloid peptides.

Stefansson, Steingrimur / Adams, Daniel L / Tang, Cha-Mei

BioTechniques

2012 Band 52, Heft 5

Abstract: Amyloids are fibrillar protein aggregates associated with a number of neurodegenerative pathologies including Alzheimer and Creutzfeldt-Jakob disease. The study of amyloids is usually based on fluorescence with the dye thioflavin-T. Although a number of ... ...

Abstract	Amyloids are fibrillar protein aggregates associated with a number of neurodegenerative pathologies including Alzheimer and Creutzfeldt-Jakob disease. The study of amyloids is usually based on fluorescence with the dye thioflavin-T. Although a number of amyloid binding compounds have been synthesized, many are nonfluorescent or not readily available for research use. Here we report on a class of commercial benzothiazole/benzoxazole containing fluorescent DNA intercalators from Invitrogen that possess the ability to bind amyloid Aβ1-42 peptide and hamster prion. These dyes fluoresce from 500-750 nm and are available as dimers or monomers. We demonstrate that these dyes can be used as acceptors for thioflavin-T fluorescence resonance energy transfer as well as reporter groups for binding studies with Congo red and chrysamine G. As more potential therapeutic compounds for these diseases are generated, there is a need for simple and inexpensive methods to monitor their interactions with amyloids. The fluorescent dyes reported here are readily available and can be used as tools for biochemical studies of amyloid structures and in vitro screening of potential therapeutics.
Mesh-Begriff(e)	Alzheimer Disease ; Amyloid beta-Peptides/analysis ; Amyloid beta-Peptides/chemistry ; Amyloid beta-Peptides/metabolism ; Benzothiazoles/chemistry ; Benzothiazoles/metabolism ; Benzoxazoles/chemistry ; Benzoxazoles/metabolism ; Congo Red ; Fluorescent Dyes/chemistry ; Fluorescent Dyes/metabolism ; Humans ; Intercalating Agents/chemistry ; Intercalating Agents/metabolism ; Peptide Fragments/analysis ; Peptide Fragments/chemistry ; Peptide Fragments/metabolism ; Prions/analysis ; Prions/chemistry ; Prions/metabolism
Chemische Substanzen	Amyloid beta-Peptides ; Benzothiazoles ; Benzoxazoles ; Fluorescent Dyes ; Intercalating Agents ; Peptide Fragments ; Prions ; amyloid beta-protein (1-42) ; Congo Red (3U05FHG59S) ; benzothiazole (G5BW2593EP)
Sprache	Englisch
Erscheinungsdatum	2012-05-01
Erscheinungsland	England
Dokumenttyp	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	48453-2
ISSN	1940-9818 ; 0736-6205
ISSN (online)	1940-9818
ISSN	0736-6205
DOI	10.2144/000113873
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: High-throughput Peptide epitope mapping using carbon nanotube field-effect transistors.

Stefansson, Steingrimur / Knight, Martha / Kwon, Hena H / Stefansson, Lára A / Ahn, Saeyoung Nate

International journal of peptides

2013 Band 2013, Seite(n) 849303

Abstract: Label-free and real-time detection technologies can dramatically reduce the time and cost of pharmaceutical testing and development. However, to reach their full promise, these technologies need to be adaptable to high-throughput automation. To ... ...

Abstract	Label-free and real-time detection technologies can dramatically reduce the time and cost of pharmaceutical testing and development. However, to reach their full promise, these technologies need to be adaptable to high-throughput automation. To demonstrate the potential of single-walled carbon nanotube field-effect transistors (SWCNT-FETs) for high-throughput peptide-based assays, we have designed circuits arranged in an 8 × 12 (96-well) format that are accessible to standard multichannel pipettors. We performed epitope mapping of two HIV-1 gp160 antibodies using an overlapping gp160 15-mer peptide library coated onto nonfunctionalized SWCNTs. The 15-mer peptides did not require a linker to adhere to the non-functionalized SWCNTs, and binding data was obtained in real time for all 96 circuits. Despite some sequence differences in the HIV strains used to generate these antibodies and the overlapping peptide library, respectively, our results using these antibodies are in good agreement with known data, indicating that peptides immobilized onto SWCNT are accessible and that linear epitope mapping can be performed in minutes using SWCNT-FET.
Sprache	Englisch
Erscheinungsdatum	2013-07-14
Erscheinungsland	United States
Dokumenttyp	Journal Article
ZDB-ID	2570929-X
ISSN	1687-9775 ; 1687-9767
ISSN (online)	1687-9775
ISSN	1687-9767
DOI	10.1155/2013/849303
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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