Contribution of reutericyclin production to the stable persistence of Lactobacillus reuteri in an industrial sourdough fermentation

Reutericyclin is a small molecular weight antibiotic produced by the sourdough isolate Lactobacillus reuteri LTH2584. This strain was isolated from an industrial sourdough, SER, in 1988. To determine whether reutericyclin formation contributes to the stable persistence of L. reuteri in sourdough, evaluations were made on whether reutericyclin-producing strains were among L. reuteri isolates from the SER sourdough obtained in 1994 and 1998. These strains were characterised on species and strain level by physiological tests and randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) patterns. Reutericyclin production in dough was evaluated by two methods, a bioassay and HPLC. Throughout 10 years of continuous propagation, reutericyclin-producing L. reuteri strains were present in SER sourdough. All isolates exhibited similar physiological properties and molecular typing revealed closely related patterns. Two isolates obtained in 1994 and 1998 were identical. Reutericyclin produced in situ by L. reuteri was active in dough against reutericyclin-sensitive L. sanfranciscensis. The reutericyclin concentration in dough fermented with L. reuteri was 5 mg kg(-1). The results indicate that reutericyclin production contributed to the stable persistence of L. reuteri in sourdough. Because reutericyclin is produced in active concentrations during sourdough fermentations, it is a suitable candidate for use as natural preservative.     

Development of LHPs with ceramic wick

The ceramic porous wick is proposed as an alternative to wicks made of metal and plastic for Loop Heat Pipes (LHP) applications. Performance tests of two LHPs using acetone and water as working fluids were carried out for power inputs up to 25 W. The evaporators have a stainless steel cylindrical assembly, with 80 mm of length and 10 mm of inner diameter. The ceramic porous wick has 50% of porosity, 1–3 μm of pore radius distribution and a permeability of about 35 × 10^?15 m². The active zone length of the evaporators is 25 mm. For a limited operation temperature of 100 °C, the LHPs were able to transfer up to 25 and 15 W using acetone and water, respectively, at steady state condition. An operation analysis concerning the effects of the LHP inclination, the heat sink temperature and LHP thermal resistances is also presented. Despite the relative good performance of the LHPs, further researches are still required taking into account changes related to properties of the ceramic porous wick in particular and improvements in the whole LHP design in general.     

Zustandsgrößen und Transportkoeffizienten von binären Gasgemischen — I: Ein einfaches Verfahren zur genauen Bestimmung des Zweiten Virialkoeffizienten binärer Gasgemische

A simple method is presented for the accurate calculation of the crossterm B₁₂ of binary mixture second virial coefficients. For evaluation the second virial coefficients of the components and the relation T_BM(x) between the Boyle-temperatures and the concentration x of the examined mixture are required. The determination of this characteristic function limiting the validity range of the new method, is described. Finally, the crossterm B₁₂ is evaluated for 3 mixtures for which accurate experimental values are available. The agreement between measured and calculated properties is good and in some cases even excellent.     

Query Answering for OWL-DL with rules

Both OWL-DL and function-free Horn rules are decidable fragments of first-order logic with interesting, yet orthogonal expressive power. A combination of OWL-DL and rules is desirable for the Semantic Web; however, it might easily lead to the undecidability of interesting reasoning problems. Here, we present a decidable such combination where rules are required to be DL-safe: each variable in the rule is required to occur in a non-DL-atom in the rule body. We discuss the expressive power of such a combination and present an algorithm for query answering in the related logic extended with DL-safe rules, based on a reduction to disjunctive programs.     

Mercury transport and fate in the Gulf of Trieste (Northern Adriatic)—a two-dimensional modelling approach

The Gulf of Trieste is subject to mercury pollution from the So a River which drains polluted sediments from the region of a former mercury mine in Idrija, Slovenia. This has resulted in elevated mercury levels in some marine organisms. Due to a concern for human health, a study has been undertaken to predict mercury contamination trends through the use of a field program and a mathematical model. An annual mercury mass balance of the Gulf is presented first in the paper. This confirms the assumption of the importance of the particulate mercury loads and sedimentation in the mercury cycle. A two-dimensional (2D) advection-dispersion model for non-conservative pollutants which simulates mercury cycling in the Gulf, is then described. This model incorporates the results of a 2D steady-state, primarily wind-driven hydrodynamic model and a 2D sediment transport model. A coupling of the submodels and verification of the integral mercury cycling model are also presented.     

Helios, current coupling collision probability method, applied for solving the NEA C5G7 MOX benchmark

As part of an effort to test the ability of current transport codes to treat reactor core problems without spatial homogenization, the lattice code HELIOS was employed to perform criticality calculations. The test consists in seven-group calculations of the C5 MOX fuel assembly problem specified by Cavarec et. al. [1]. This problem, known as C5G7 MOX Benchmark, is described in the Benchmark Specification [2] and comprises two cases — two and three-dimensional geometry. There are four fuel assemblies — two with MOX fuel, the other two with UO₂ fuel. Each fuel assembly is made up of a 17×17 lattice of square fuel-pin cells. Fuel pin compositions are specified in the Benchmark Specification, which also provides seven-group transport-corrected isotropic scattering cross-sections for U0₂, the three MOX enrichments, the guide tubes, the fission chamber and the moderator. This paper preset is the methodology employed in solving the C5G7 MOX Fuel Assembly Problem using the transport code HELIOS.     

The Characterization of Sufficient Visibility in the Direct Reference Plane Approach for Multiple Views with Missing Data

Rother and Carlsson introduced the Direct Reference Plane method for obtaining a projective reconstruction from a multi-view system, presuming the availability of a planar reference quadrangle in each view. In this method feature points and camera centres are obtained simultaneously by solving a system of homogeneous linear equations. Each feature-camera visibility pair corresponds to two equations in this system. In this paper we derive a count criterion for characterizing sufficient visibility, yielding a system of linearly independent equations that “determines” feature points and camera centres. Finally we discuss some principles to extend the configuration of feature points and camera centres while maintaining sufficient visibility. First online version published in February, 2006     

Optical properties of micrometer size water droplets studied by cavity ringdown spectroscopy

Optical extinction by homogeneous, pure water droplets of 30 to 70 microm diameter produced by a vibrating orifice aerosol generator has been studied by pulsed cavity ringdown (CRD) spectroscopy at lambda=560 nm under ambient conditions. Experimental sensitivity of better than 1% achieved in measurements of CRD times enabled detection of changes in laser light losses per pass due to changes in the number and size of particles within the laser beam volume. By systematically changing the droplet size in the cavity while recording the CRD time, a periodic modulation in the value of the loss per pass was observed. The modulation is caused by the oscillatory nature of the extinction efficiency, which was subsequently inferred and compared with the results of theoretical calculations based on Mie theory.