Effects of polyphosphates and heat on selected Gram-positive bacteria important in foods

In one series of studies, a simple well-plate technique was utilized to determine the effect of various metals on the growth of microorganisms in media containing different polyphosphates. Aspergillus flavus and four Gram-positive bacteria were almost completely inhibited by media containing 1% of various alkaline polyphosphates, whereas four Gram-negative bacteria were not. Significant differences were observed between the type of polyphosphate added, the type of metal added, and the species of Gram-positive bacterium inhibited. A method for determining the amount of calcium and magnesium in water was modified to detect free Mg[superscript]2+ by replacing EDTA with phosphate. The addition of free Mg[superscript]2+, but not Mg[superscript]2+ chelated by tetrasodium pyrophosphate, permitted the growth of Bacillus cereus on a medium containing tetrasodium pyrophosphate. It is speculated that polyphosphates specifically inhibit Gram-positive bacteria because the polyphosphates have higher affinities than the cation-binding sites within Gram-positive cell walls for essential metal cations;In another series of studies, Listeria monocytogenes F5069 was suspended in either Trypticase soy-0.6% yeast extract broth (TSBYE) or sterile, whole milk and heated at 62.8°C in sealed thermal death time tubes. Severely heat-injured cells were recovered in TSBYE when incubated within sealed thermal death time tubes because of the formation of reduced conditions in the depths of the TSBYE after heating. Also, the use of anaerobic Hungate techniques significantly increased recovery in Trypticase soy yeast extract broth containing 1.5% agar (TSBYEA), compared with aerobically incubated controls. The exogenous addition of catalase, but not superoxide dismutase, slightly increased the recovery of heat-injured cells in TSBYEA incubated aerobically. Thermotolerance increased with increasing time and temperature of sublethal heat shock; however, cells grown at 43°C were more heat resistant than cells heat shocked at 43°C or cells grown at lower temperatures. Under the conditions of the present study, high levels of Listeria monocytogenes could survive the minimum low-temperature, long-time process required by the U.S. Food and Drug Administration for pasteurizing milk. The possibilities that injured cells can be recovered in selective media under strictly anaerobic conditions and heat shock proteins cause thermotolerance by preventing the denaturation of catalase and superoxide dismutase are discussed

Konzeption eines generischen Datenmodells für iOS im Kontext akustischer Lokalisation

Auf mobilen Endgeräten wirft das Genre um akustische Spiele einige interessante Konzepte und Möglichkeiten auf. Dies gilt insbesondere in Kombination mit der Verarbeitung von Bewegungsdaten und dem Identifizieren von Geräuschquellen. Im Rahmen dieser Arbeit wird ein generisches Datenmodell für Anwendungen dieser Art entwickelt und implementiert. Das erarbeitete Konzept beruht auf funktionalen Anforderungen, welche sich durch eine Analyse von drei im Weiteren ausgeführten, fiktiven Anwendungen und deren Aggregation ergeben. Diese werden zuerst vorgestellt und voneinander abgegrenzt. Im Anschluss daran wird die Spezifikation erarbeitet, welche vom System und dem Datenmodell erfüllt werden müssen, um alle vorgestellten Anwendungsfälle passend abbilden zu können. Bezüglich dieser Anforderungen wird das Datenmodell als mögliche Lösung vorgestellt und anhand einer Implementierung genauer betrachtet. Abschließend wird das gefundene generische Datenmodell mit einem problemspezifischen verglichen und bewertet

Reliability based design of frames with limited residual strain energy capacity

The aim of this paper is to create new type of plastic limit design procedures where the influence of the limited load carrying capacity of the beam-to-column connections of elasto-plastic steel (or composite) frames under multi-parameter static loading and probabilistically given conditions are taken into consideration. In addition to the plastic limit design to control the plastic behaviour of the structure, bound on the complementary strain energy of the residual forces is also applied. If the design uncertainties (manufacturing, strength, geometrical) are taken into consideration at the computation of the complementary strain energy of the residual forces the reliability based extended plastic limit design problems can be formed. Two numerical procedures are elaborated. The formulations of the problems yield to nonlinear mathematical programming which are solved by the use of sequential quadratic algorithm

Lithium and aluminium carbamato derivatives of the utility amide 2, 2, 6, 6- tetramethylpiperidide

Insertion of CO2 into the metal-N bond of a series of synthetically-important alkali-metal TMP (2,2,6,6-tetramethylpiperidide) complexes has been studied. Determined by X-ray crystallography, the molecular structure of the TMEDA-solvated Li derivative shows a central 8-membered (LiOCO)2 ring lying in a chair conformation with distorted tetrahedral lithium centres. While trying to obtain crystals of a THF solvated derivative, a mixed carbonato/carbamato dodecanuclear lithium cluster was formed containing two central (CO3)2- fragments and eight O2CTMP ligands with four distinct bonding modes. A bisalkylaluminium carbamato complex has also been prepared via two different methods (CO2 insertion into a pre-formed Al-N bond and ligand transfer from the corresponding lithium reagent) which adopts a dimeric structure in the solid state

Deep Extragalactic VIsible Legacy Survey: Data Release 1 blended spectra search for candidate strong gravitational lenses

Here, we present a catalogue of blended spectra in Data Release 1 of the Deep Extragalactic VIsible Legacy Survey (DEVILS) on the Anglo-Australian Telescope. Of the 23 197 spectra, 181 showed signs of a blend of redshifts and spectral templates. We examine these blends in detail for signs of either a candidate strong lensing galaxy or a useful overlapping galaxy pair. One of the three DEVILS target fields, COSMOS (D10), is close to complete and it is fully imaged with Hubble Space Telescope Advanced Camera for Surveys, and we visually examine the 57 blended spectra in this field in the F814W postage stamps. Nine are classical strong lensing candidates with an elliptical as the lens, out to higher redshifts than any previous search with spectroscopic surveys such as Sloan Digital Sky Survey (SDSS) or Galaxy And Mass Assembly. The gravitational lens candidate success rate is similar to earlier such searches (0.1 per cent). Strong gravitational lenses identified with blended spectroscopy have typically shown a high success rate (\u3e70 per cent), which make these interesting targets for future higher resolution lensing studies, monitoring for supernova cosmography, or searches for magnified atomic hydrogen signal

Deep Extragalactic VIsible Legacy Survey: Data Release 1 blended spectra search for candidate strong gravitational lenses

Here, we present a catalogue of blended spectra in Data Release 1 of the Deep Extragalactic VIsible Legacy Survey (DEVILS) on the Anglo-Australian Telescope. Of the 23 197 spectra, 181 showed signs of a blend of redshifts and spectral templates. We examine these blends in detail for signs of either a candidate strong lensing galaxy or a useful overlapping galaxy pair. One of the three DEVILS target fields, COSMOS (D10), is close to complete and it is fully imaged with Hubble Space Telescope Advanced Camera for Surveys, and we visually examine the 57 blended spectra in this field in the F814W postage stamps. Nine are classical strong lensing candidates with an elliptical as the lens, out to higher redshifts than any previous search with spectroscopic surveys such as Sloan Digital Sky Survey (SDSS) or Galaxy And Mass Assembly. The gravitational lens candidate success rate is similar to earlier such searches (0.1 per cent). Strong gravitational lenses identified with blended spectroscopy have typically shown a high success rate (\u3e70 per cent), which make these interesting targets for future higher resolution lensing studies, monitoring for supernova cosmography, or searches for magnified atomic hydrogen signal