Microbial interactions in cheese: implications for cheese quality and safety

International audienceThe cheese microbiota, whose community structure evolves through a succession of different microbial groups, plays a central role in cheese-making. The subtleties of cheese character, as well as cheese shelf-life and safety, are largely determined by the composition and evolution of this microbiota. Adjunct and surface-ripening cultures marketed today for smear cheeses are inadequate for adequately mimicking the real diversity encountered in cheese microbiota. The interactions between bacteria and fungi within these communities determine their structure and function. Yeasts play a key role in the establishment of ripening bacteria. The understanding of these interactions offers to enhance cheese flavour formation and to control and/or prevent the growth of pathogens and spoilage microorganisms in cheese

Assessment of the microbial diversity at the surface of Livarot cheese using culture-dependent and independent approaches

International audienceThe microbial diversity of the surface of a commercial red-smear cheese, Livarot cheese, sold on the retail market was studied using culture-dependent and independent approaches. Forty yeasts and 40 bacteria from the cheese surface were collected, dereplicated using single-strand conformation polymorphism (SSCP) analysis and identified using rRNA gene sequencing for the culture-dependent approach. The cultureindependent approach involved cloning and sequencing of the 16S rRNA gene and SSCP analysis from total DNA extracted from the cheese. The most dominant bacteria were Microbacterium gubbeenense, Leucobacter komagatae and Gram-negative bacteria from the Gamma-Proteobacteria class. Fluorescence in situ hybridization (FISH) analysis was also used to study the cheese microbial diversity with class-level and specific rRNAtargeted probes for bacteria and yeasts, respectively. FISH analysis confirmed that Gamma-Proteobacteria were important microorganisms in this cheese. Four specific FISH probes targeting the dominant yeasts present in the cheese, Candida catenulata, Candida intermedia, Geotrichum spp. and Yarrowia lipolytica, were also designed and evaluated. These probes allowed the detection of these yeasts directly in cheese. The use of the rRNA gene-based approach combined with FISH analysis was useful to investigate the diversity of a surface microbial consortium from cheese

Answering a Questionnaire Using Eyetracking

The beginning of eye tracking research lies far back in the past. Since eye tracking costs decreased over the past years, the usage of an eye tracker for everyday matters, like the interaction with a personal device, becomes more and more attractive. In the present work, the realization of interacting with a computer interface with only the help of an eye tracker is illustrated. The conducted study examines the acceptance and usability of such a system. Therefore, three different interaction methods have been implemented. In a study, the participants had to complete a questionnaire with those interaction methods using a Windows application and a low-cost eye tracking device. All in all, the study results imply that the number of negative aspects about this system outweigh the positive ones. The biggest issue was the restriction of mobility during the usage of the tracking device. In addition, the usage of the system turned out to be rather exhausting for the eyes. Generally speaking, among the three implemented interaction methods, the interaction method that combines gaze with a second input modality (a keyboard) scored best in terms of interaction speed and usefulness considering the completion of a questionnaire

Construction of a dairy microbial genome catalog opens new perspectives for the metagenomic analysis of dairy fermented products

Microbial communities of traditional cheeses are complex and insufficiently characterized. The origin, safety and functional role in cheese making of these microbial communities are still not well understood. Metagenomic analysis of these communities by high throughput shotgun sequencing is a promising approach to characterize their genomic and functional profiles. Such analyses, however, critically depend on the availability of appropriate reference genome databases against which the sequencing reads can be aligned. We built a reference genome catalog suitable for short read metagenomic analysis using a low-cost sequencing strategy. We selected 142 bacteria isolated from dairy products belonging to 137 different species and 67 genera, and succeeded to reconstruct the draft genome of 117 of them at a standard or high quality level, including isolates from the genera Kluyvera, Luteococcus and Marinilactibacillus, still missing from public database. To demonstrate the potential of this catalog, we analysed the microbial composition of the surface of two smear cheeses and one blue-veined cheese, and showed that a significant part of the microbiota of these traditional cheeses was composed of microorganisms newly sequenced in our study. Our study provides data, which combined with publicly available genome references, represents the most expansive catalog to date of cheese-associated bacteria. Using this extended dairy catalog, we revealed the presence in traditional cheese of dominant microorganisms not deliberately inoculated, mainly Gram-negative genera such as Pseudoalteromonas haloplanktis or Psychrobacter immobilis, that may contribute to the characteristics of cheese produced through traditional methods.https://doi.org/10.1186/1471-2164-15-110

The Economy of Dürrnberg-Bei-Hallein: An Iron Age Salt-mining Centre in the Austrian Alps

For the first time in English, we present a summary of the international programme of excavation work carried out between 1990 and 2001 in and around the Iron Age salt-mining complex of the Diirrnberg region, south of Salzburg. First we describe the results of excavation in the prehistoric adits, and of work to locate and survey associated settlements. This is followed by a series of specialist reports embracing floral and faunal remains, palaeodiet and parasitology, leather and woodworking and other crafts. The evidence suggests that a complex inter-relationship existed between the Diirrnberg and other communities in the Alpine foreland. It is assumed that the Diirrnberg was under the control of an elite - perhaps a local dynasty whose wealth is reflected in the grave

Development of an electronic monitor for the determination of individual radon and thoron exposure

The carcinogenic effect of the radio isotope Rn-222 of the noble gas radon and its progeny, as well as its residential distribution, are well studied. In contrast, the knowledge about the effects and average dwelling concentration levels of its radio isotope Rn-220 (thoron) is still limited. Generally, this isotope has been assumed to be a negligible contributor to the effective annual dose. However, only recently it has been pointed out in several international studies, that the dose due to thoron exceeds the one from Rn-222 under certain conditions. Additionally, radon monitors may show a considerable sensitivity towards thoron which was also not accounted for in general. Therefore a reliable, inexpensive exposimeter, which allows to distinguish between decays of either radon and thoron, is required to conduct further studies. The scope of this thesis was to develop an electronic radon/thoron exposimeter which features small size, low weight and minimal power consumption. The design is based on the diffusion chamber principle and employs state-of-the-art alpha particle spectroscopy to measure activity concentrations. The device was optimized via inlet layout and filter selection for high thoron diffusion. Calibration measurements showed a similar sensitivity of the monitor towards radon and thoron, with a calibration factor of cfRn-222 = 16.2±0.9 Bq×m-3/cph and cfRn-220 = 14.4±0.8 Bq×m-3/cph, respectively. Thus, the radon sensitivity of the device was enhanced by a factor two compared to a previous prototype. The evaluation method developed in this work, in accordance with ISO 11665 standards, was validated by intercomparison measurements. The detection limits for radon and thoron were determined to be C#Rn-222 = 44.0 Bq/m3 and C#Rn-220 = 40.0 Bq/m3, respectively, in case of a low radon environment, a one-hour measurement interval, and a background count rate of zero. In contrast, in mixed radon/thoron concentrations where the Po-212 peak must be used for thoron concentration determination, a calibration factor of cfRn-220 = 100±10 Bq×m-3/cph was measured, yielding a detection limit of C#Rn-220 = 280 Bq/m3. Further, Monte Carlo (MC) simulations were performed by means of various codes including Geant4, to study the effect of the variation of parameters influencing the calibration factors. The results showed reasonable agreement between simulated and acquired spectra, with differences being below 8%, thus validating the employed simulation model. The simulations indicated a significant impact of environmental parameters, such as temperature and pressure, on the measured spectra and accordingly on the calibration factor. Therefore the calibration factor was quantified as a function of temperature, relative humidity and pressure as well as chamber volume. For devices with increased detection volume a considerable influence of air density changes, corresponding to altitudes from 0-5,000 m, and temperatures from -25 to 35 °C, on the calibration factor of up to 32% was observed. In contrast, for devices with standard housing the calibration factor changed only up to 4%. When increasing the detection volume compared to the employed standard housing by at least a factor of four, a maximum increase of the sensitivity of about 20% was found, at the expense of device portability. On the contrary, when reducing the height of the housing by 10~$mm$, which yields 40% less volume, a decrease of sensitivity by 30% and 41% for radon and thoron was observed, respectively. Finally, devices were used and tested at different realistic conditions, such as mines, radon spas, and dwellings with mixed Rn-222 and Rn-220 environments. Measurements in a salt mine with the device developed within the framework of this thesis revealed maximum radon concentrations of up to 1.0 kBq/m3. In the Bad Gastein Heilstollen, Rn-222 concentrations up to 24.3 kBq/m3 were found, in agreement with an AlphaGuard reference device. First measurements in radon/thoron environments of about 200 Bq/m3 each, in a clay model house at the Helmholtz Center Munich, showed reasonable agreement with reference devices, thus validating the introduced evaluation method. First measurements in a private Bavarian clay house revealed a low thoron concentration of about CRn-220 = 13.0±3.0 Bq/m3, in comparison to a high radon concentration of CRn-222 = 200±70 Bq/m3

Automatisierung der Lagenscharsynthese als Verfahren der Maßsynthese für Viergelenke bei gegebenen Koppelkurven

Zur Erfüllung von Punktführungsaufgaben werden Viergelenkgetriebe aufgrund ihrer Vielfalt von möglichen Koppelkurven in vielen Bereichen der Technik eingesetzt. Sie sind robust, kostengünstig und weisen speziell gegenüber seriellen Strukturen mit höheren Freiheitsgraden sehr gute dynamische Eigenschaften auf. Allein die Maßsynthese stellt im Konstruktionsalltag ein Problem dar. Auch wenn die gängigen Verfahren beherrscht werden, bieten diese oft nur die Möglichkeit wenige Punktlagen exakt zu erfüllen. In diesem Artikel wird eine Software auf Grundlage der Lagenscharsynthese vorgestellt. Im Vorfeld wurden Untersuchungen durchgeführt um auch unerfahrene Nutzer durch den Syntheseprozess zu führen und ihm mögliche Lösungsräume aufzeigen zu können. Schließlich können die bestimmten, umlauffähigen Viergelenke simuliert, und bewertet werden.For performance a point-guiding-challenge the usage of four-bar-linkages in technical environment is helpful because of their plentitude of possible trajectories. They are robust, low-cost, and implement high-dynamic properties especially seen in contrast to with structures of higher degrees of freedom. Only the dimensioning of the bars and locating of fixed bearing resolve with problems. Also the usual methods are well known, they enable the exact synthesis for only four positions. So in this article a program based on the “Lagenscharsynthese” is presented. In the forefront analyses were made to check, if inexperienced persons could be guided thru the process of synthesis and show them areas of possible solutions. Finally the defined rotatable four-bar-linkages can be simulated and evaluated

Berechnete Erzeugung von dreidimensionalen Oberflächenmodellen im STL-Format aus der Beschreibung planarer Mechanismen für die generative Fertigung durch selektives Lasersintern

Der Beitrag beschreibt detailliert wie die Bestandteile eines planaren Mechanismus als geometrische Körper modelliert und im STL-Dateiformat für den 3D-Druck gespeichert werden können. Anhand des Entwurfs eines Viergelenks wird die komplette Kette vom mathematischen Modell bis hin zum Schreiben der druckbaren STL-Datei beschrieben. Die erläuterten Beispiele können leicht in MATLAB nachvollzogen werden. Die Autoren sind überzeugt, dass der Entwurf von Mechanismen vor einem Umbruch steht, da ein automatischer Entwurf eines Mechanismus aus einer Bewegungsanforderung möglich wird und der 3D-Druck eines solchen kostengünstig und kurzfristig möglich ist. In Kombination mit preiswerten Motoren und einfachste Steuerungen stellen generativ gefertigte Mechanismen eine Alternative zur komplexen Programmierung von Robotern dar.This paper describes in detail how to generate STL-Files using MATLAB for the generation of Mechanisms and Kinematic structures. For a 4Bar-Linkage, all design steps to come from a kinematic description to a 3D printable spatial object are explained. The authors are convinced that the design of mechanisms will become popular again, since the automatic design to fulfill a movement task is possible. 3D printing of mechanisms is cheap and possible within hours. Off-the-shelf motors and simple control boards are a real alternative to a complex programming task for 6DoF robots

Система поддержки принятие решений при проведении клинических исследований

Разработка программного обеспечения для проведения клинических исследований. Данное приложение может применяться для обеспечения целостности данных, безопасности субъекта исследования, качества продукта в ходе проведения исследования, что приведет к автоматизации рутинных процессов и будет способствовать повышению скорости и качества проводимых исследований.Development of software for conducting clinical trials. This application can be used to ensure data integrity, security of the research subject, and product quality during the research, which will lead to automation of routine processes and will help to improve the speed and quality of research