Search results for "Oxygen sensor"
showing 7 items of 7 documents
Stimulation of Fe-S cluster insertion into apoFNR by Escherichia coli glutaredoxins 1, 2 and 3 in vitro.
2004
Abstract The oxygen sensor fumarate nitrate reductase regu-lator (FNR) of Escherichia coli contains in the active (anaerobic)state a [4Fe–4S] 2þ cluster which is lost after exposure to O 2 .Inaerobically prepared apoFNR, or in FNR obtained by treatmentof [4Fe–4S] FNR with O 2 in vitro, intramolecular cysteinedisulfides are found, including the cysteine residues which serveas ligands for the Fe–S cluster. It is shown here that thereconstitution of [4Fe–4S] FNR from this form of aerobicapoFNR was preceded by a long lag phase when glutathione wasused as the reducing agent. Addition of E. coli glutaredoxins(Grx) 1, 2 or 3 decreased the lag phase greatly and stimulatedthe reconstitution rate slig…
Nanofilm metal layers as vacuum quality sensors
2010
Abstract A monitoring device for vacuum quality is realized by lowest cost single use oxygen sensors for vacuum insulation panels. They use the pressure dependence of oxide layer growth thickness on electrically measured metal nanofilms. These films were manufactured by e-beam evaporation, characterized in terms of resistance change with subsequent modeling of underlying mechanisms.
Nanofilm Low Cost Oxygen Sensors
2009
Abstract The resitivity change of ultra thin metals under air exposure is used for vacuum or inert gas packaging control. In order to reach low cost, single use applications, few nm thin Aluminum layers were deposited on PET substrates and combined with wireless electronic readout circuitry. The sensor respose is characterized by resistance changes and explained in terms of multiphase diffusion mechanisms which are very sensitive to technological parameters.
Alternative respiratory pathways of Escherichia coli: energetics and transcriptional regulation in response to electron acceptors
1997
AbstractThe electron-transport chains of Escherichia coli are composed of many different dehydrogenases and terminal reductases (or oxidases) which are linked by quinones (ubiquinone, menaquinone and demethylmenaquinone). Quinol:cytochrome c oxido-reductase (`bc1 complex') is not present. For various electron acceptors (O2, nitrate) and donors (formate, H2, NADH, glycerol-3-P) isoenzymes are present. The enzymes show great variability in membrane topology and energy conservation. Energy is conserved by conformational proton pumps, or by arrangement of substrate sites on opposite sides of the membrane resulting in charge separation. Depending on the enzymes and isoenzymes used, the H+/e− rat…
Detection of Single Oxygen Molecules with Fluorescence-Labeled Hemocyanins
2005
This study introduces a method to detect individual oxygen molecules by fluorescence microscopy of single hemocyanins. These respiratory proteins from a tarantula bind oxygen with high affinity. A spectrometric signature of the oxygenated protein is transferred to an attached fluorescence label, which can be detected at the single-molecule level. This technique opens new perspectives for the development of small and sensitive oxygen sensors as well as for the investigation of cooperative oxygen binding in respiratory proteins.
Zirconia Based Nanomaterials for Oxygen Sensors – Generation, Characterisation and Optical Properties
2007
Microwave driven hydrothermal synthesis and hydrothermal synthesis were used to obtain ZrO2 nanopowders. Their production with varying phase composition, the characterisation and selected optical properties concerning their potential use as luminescence oxygen sensors are reported. It was found that the powders obtained by the microwave driven hydrothermal method and annealed at 750 0C in air show experiment repeatability within an accuracy of 6 %.
Pyrene-Capped CdSe@ZnS Nanoparticles as Sensitive Flexible Oxygen Sensors in Non-Aqueous Media**
2014
A flexible, highly sensitive sensor of oxygen in non-aqueous solvents is described. It consists of CdSe/ZnS nanoparticles decorated with a considerable number of pyrene units, thus making the formation of the pyrene excimer possible. The emission of the pyrene excimer and that of the nanoparticle are suitably separated from each other and also from the excitation wavelength. This sensor can be applied as a ratiometric oxygen sensor by using the linear response of the pyrene excimer lifetime combined with the linear response of the nanoparticle excited state lifetime. This nanohybrid has been assayed in seven media with different dielectric constants and viscosities over the whole oxygen con…