Antibiotic susceptibility of Bifidobacterium thermophilum and Bifidobacterium pseudolongum isolates from animal sources

The widespread use of antimicrobial substances has led to resistant populations of microorganisms in several ecosystems. In animal husbandry, the application of antibiotics has contributed to resistance development in pathogenic and commensal bacteria. These strains or their resistance genes can be spread along several ecological routes, including the food chain. Antibiotic resistance is important in terms of the safety of industrial strains, such as probiotics for food and feed. Bifidobacterium thermophilum and Bifidobacterium pseudolongum are known to comprise the major part of the bifidobacterial microbiota in the gut and feces of cattle and pigs. In this study, the antimicrobial susceptibility in bifidobacterial isolates of these species was investigated. Isolates from the beef and pork production chain were identified and typed to strain level, and the antimicrobial susceptibility level was tested to a set of antibiotics. Isolates with low susceptibility levels were screened by PCR for already described resistance genes. Strains atypically resistant to clindamycin, erythromycin, and tetracycline were determined. The resistance genes tet(O), tet(W), and erm(X) were detected in the bifidobacterial species that were examined.     

Ein Hochspannungsmesser für 600 kV

Zusammenfassung Das neue Meßverfahren mittels elektrischen Druckmessers und Druckspulsystems ist auf seine Fehler hin untersucht worden. Es konnte durch Vergleichsmessungen mit einem absoluten Thomson-Elektrometer in Luft für 175 kV der Beweis erbracht werden, daß die Hochspannungsmesser, die auf der neuen Grundlage entwickelt worden sind, auf Bruchteile eines Prozent den gemessenen Spannungswert absolut und relativ genau erfassen. Daher ist aufbauend auf den Erfahrungen mit dem früheren Hochspannungsmesser für 200 kV ein größeres Instrument für 400 kV Effek-tiv- bzw. 600 kV Scheitelwert errichtet worden. Dieses Gerät besitzt gegen das frühere hochspannungs- und meßtechnisch eine Reihe Verbesserungen. Seine Beschreibung findet sich in der vorhergehenden Arbeit. Da sich dieses Instrument, wie sein kleinerer Vorgänger, bewährt hat, scheinen nun kaum noch Schwierigkeiten für den Bau von Instrumenten für noch höhere Spannungen bis 1 Mill V zu bestehen.Herr Prof. Dr.-Ing. Dr.-Ing. E. h. Rogowski hat die Anregung zu der vorliegenden Arbeit gegeben. Ihm möchte ich verbindlichen Dank für sein stetes Interesse und viele fördernden Ratschläge aussprechen. Auch gilt mein Dank den Herren Prof. Dr.-Ing. Opitz und Prof. Dr. Starke, die mir Instrumente für die Durchführung meiner Messungen zur Verfügung gestellt haben.Die Helmholtz-Gesellschaft hat die Arbeit mit geldlichen Mitteln unterstützt; ich sage ihr meinen besten Dank für diese Hilfe.     

Handsketching as a human factor aspect in graphical interaction

For some years a lot of effort has been put into improving the human-computer interface in CAD-systems. After a short introduction on input problems in design processes, some of this work is reported here as well as a fairly new method, handsketching. In the third part of this paper a special system called CASUS is thoroughly explained from the user's point of view. A fourth part deals with the authors' conviction that psychological theories and methods are necessary in order to create still better interfaces. In the last chapter the system presented with all its interface features is compared to some human factor considerations discussed before. No attention is paid to the fact that very often the quality of work is changed by introducing CAD-systems. Though the designer's situation can be very often improved much more by designing his entire work, this paper lays claim only to designing a tool for the designer's hand.     

Influence of a reduced wearing time on the attenuation of hearing protectors assessed via temporary threshold shifts

Valuable recommendations for the choice, utilization, care, and maintenance, and for the measurement of sound attenuation of hearing-protective devices have been laid down in international standards. Yet, by considering the wearing time of a hearing protector, the standard DIN EN 458 assumes a scarcely understandable drastic reduction in the effective attenuation even when the device is not used for only a short time in a noise-filled area. A 30 dB sound attenuation of such a protective device would, e.g., decrease to 12 dB if it were unused for only 30 min of an 8 h shift. Thus, the actual influence of a shortened wearing time on the protection of earmuffs was tested in a laboratory study using audiometric measurements of the temporary threshold shift (TTS₂) and its recovery after exposure to noise. For that purpose, the effectiveness of a hearing-protective device depending on the amount of time worn as prognosticated by DIN EN 458 was compared with the actual physiological effect of the earmuffs. Ten test subjects (Ss) participated in three test series (TS), each. In the first of the TS, the Ss were exposed to a sound pressure of 106 dB(A) for 1 h, during which the Ss wore noise-insulating earmuffs with an attenuation of 30 dB. The Ss were exposed to the same sound pressure in TS II; however, after 30 min, the earmuffs were removed for a duration of  min. Mathematically, this reduced the sound attenuation of the earmuffs to 12 dB, i.e., the average noise level over 1 h is 94 dB, which is equivalent to 85 dB(A) over 8 h. In order to evaluate the actual additional physiological cost of TS II, the Ss were exposed to 94 dB(A)/1 h without earmuffs in a third TS. This acoustic load, which is energy equivalent to the load in TS II, is also equivalent to 85 dB(A)/8 h. The results show that the continuous wearing of the earmuffs offers secure protection. However, the energetic approach and the levelling of differently structured noise loads according to the principle of energy equivalence leads to misconceiving results. The drastic reduction of the sound attenuation of the earmuffs predicted from the energetic point of view must be regarded as exaggerated. The TTS values show that TS II – which, according to the principle of energy-damage-equivalence, should result in the same effects as TS III – represents significantly less auditory fatigue. Thus, if the earmuffs are taken off briefly, a drastic reduction in the protection – as predicted in DIN EN 458 — does not result.

Relevance to industry

The results of this study demonstrate that the standards and regulations for noise rating do not correspond with the actual physiological facts and, therefore, can only be used in a very limited manner. Utilization of the principle of energy equivalence has proven problematic not only for rating noise. This principle also leads to an essential underestimation of the attenuation of hearing protectors when these devices are taken off for only a short time in a noise-filled area.     

Untersuchungen an Caramel Curiepunkt-Pyrolyse von Caramelzuckersirupen und andere strukturspezifische Untersuchungen

Zusammenfassung Es wird über die Curiepunkt-Pyrolyse handelsüblicher Caramelzuckersirup-Proben und die Identifizerung von über 80 Pyrolysefragmenten durch kombinierte Capillargaschromatographie/ Massenspektrometrie berichtet. Mit dieser Methode sind die Proben untereinander and gegenüber Couleuren differenzierbar. Mittels Ultrafiltration wurden die Komponenten einer intensiv braunen Probe in Fraktionen unterschiedlicher Molekülmasse getrennt and nach Pyrolyse miteinander verglichen. In einer niedermolekularen Fraktion wurden nach Permethylierung Laevoglucosan, 1,6-Anhydro--d-glucofuranose, Trehalose, Cellobiose, Maltose, Isomaltose und Gentiobiose Bowie einige Difructosedianhydride nachgewiesen.

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Investigations of caramel. Curiepoint pyrolysis of caramel syrups and other investigations of structure

Summary A report is given on the investigation of commercial caramel syrups by Curiepoint pyrolysis and the identification of more than 80 pyrolysis products by capillary gas chromatography mass spectrometry. This method enables the differentiation between different caramel syrups and, additionally, between caramel syrups and caramel colours. Compounds of different molecular masses have been examined in the same manner after they have been isolated from an intense brown caramel sample by ultrafiltration. In a fraction consisting of compounds with low molecular masses laevoglucosan, 1,6-anhydro--d-glucofuranose, trehalose, cellobiose, maltose, isomaltose, gentiobiose and some difructosedianhydrides were identified by GC/MS after permethylation.