Aims
The aim of the study was to quantify the growth kinetic parameters and spoilage‐associated metabolites of an inoculated strain of Aeromonas salmonicida in pre‐rigor filleted Atlantic salmon ...(Salmo salar L.) stored in vacuum (VP) or modified atmosphere (MAP 60/40% CO2/N2) at 4 and 8°C.
Methods and Results
The maximum growth rate of A. salmonicida in VP salmon stored at 4°C was 0·56 ± 0·04 day−1 with no detectable lag‐phase and the concentration of Aeromonas reached 8·33 log CFU per g after 10 days. The growth rates and maximum population density of Aeromonas in MAP salmon were lower but the applied atmosphere did not inhibit the growth. A selection of metabolites associated with fish spoilage were quantified using 1H nuclear magnetic resonance (NMR) spectroscopy. The concentration of trimethylamine (TMA) was significantly affected by storage time and temperature, packaging atmosphere and inoculation with A. salmonicida (General Linear Model (GLM), P < 0·001 for all factors).
Conclusion
The study presents preliminary results on A. salmonicida as a potential spoilage organism in vacuum‐packaged salmon during cold storage. The combination of refrigeration and a packaging atmosphere consisting of 60/40 % CO2/N2 did not completely inhibit the growth but prevented the formation of TMA.
Significance and Impact of the Study
Little information is available on the spoilage potential of Aeromonas spp. in minimally processed salmon products under different packaging conditions. The study clearly demonstrates the importance of hurdle technology and provides data to further elucidate the significance of Aeromonas spp. as a spoilage organism.
Aims
This study was conducted to assess the effects of different storage temperatures (4–20°C), on bacterial concentrations, growth rates and community structure in fresh retail sushi, a popular ...retail product with a claimed shelf life of 2–3 days.
Methods and Results
The maximum specific growth rate based on aerobic plate count (APC) at 4°C was 0·06 h−1 and displayed a sixfold increase (0·37 h−1) at 20°C. Refrigeration resulted in no growth of hydrogen sulphide (H2S)‐producing bacteria, but this group had the strongest temperature response. The bacterial community structure was determined by PCR/DGGE (denaturing gradient gel electrophoresis). Multivariate analysis based on Bray–Curtis similarities demonstrated that temperature alone was not the major determinant for the bacterial community structure. The total concentration of aerobic bacteria was the variable that most successfully explained the differences between the communities. The dominating organisms, detected by sequencing of DNA bands excised from the DGGE gel, were Brochothrix thermosphacta and genera of lactic acid bacteria (LAB).
Conclusion
The relationship between growth rates and storage temperatures clearly demonstrates that these products are sensitive to deviations from optimal storage temperature, possibly resulting in loss of quality during shelf life. Regardless of the storage temperature, the bacterial communities converged towards a similar structure and density, but the storage temperature determined how fast the community reached its carrying capacity.
Significance and Impact of the Study
Little information is available on the microbial composition of ready‐to‐eat food that are prepared with raw fish, subjected to contamination during handling, and susceptible to microbial growth during cold storage. Moreover, the data are a good first possibility to simulate growth of APC, H2S‐producing bacteria and LAB under different temperature scenarios that might occur during production, distribution or storage.
Aims
We aim to investigate the prevalence, putative virulence factors and antimicrobial resistance of mesophilic Aeromonas isolated from ready‐to‐eat (RTE) seafood available on the Norwegian market, ...and to assess the potential risks by consuming RTE seafood to consumers.
Methods and Results
The prevalence of mesophilic Aeromonas in 148 RTE seafood was investigated and the highest prevalence was found in retail sushi (17%), followed by oysters (10%), fresh salmon loins (10%) and scallops (4%). Among 43 Aeromonas isolates, 75% of them were identified as A. media, 23% as A. salmonicida and 2% as A. bestiarum based on partial gryB gene sequencing. Aeromonas isolates were potentially pathogenic due to the presence of four virulence genes: alt (73%), hylA (22%), aerA (17%) and act (6%). In addition, all isolates were resistant to ampicillin and erythromycin. Most of the isolates (98%) were multidrug resistant.
Conclusions
The occurrence of potentially pathogenic and multidrug‐resistant Aeromonas strains in RTE seafood implies a potential risk to consumers. Our finding suggests that RTE seafood could be a potential vehicle for the transfer of virulent and multidrug‐resistant Aeromonas.
Significance and Impact of the Study
To our knowledge, this is the first study to report multiple antibiotic resistance in Aeromonas associated with RTE seafood in Norway.
This article presents an X‐ray microscopy approach for mapping deeply embedded dislocations in three dimensions using a monochromatic beam with a low divergence. Magnified images are acquired by ...inserting an X‐ray objective lens in the diffracted beam. The strain fields close to the core of dislocations give rise to scattering at angles where weak beam conditions are obtained. Analytical expressions are derived for the image contrast. While the use of the objective implies an integration over two directions in reciprocal space, scanning an aperture in the back focal plane of the microscope allows a reciprocal‐space resolution of ΔQ/Q < 5 × 10−5 in all directions, ultimately enabling high‐precision mapping of lattice strain and tilt. The approach is demonstrated on three types of samples: a multi‐scale study of a large diamond crystal in transmission, magnified section topography on a 140 µm‐thick SrTiO3 sample and a reflection study of misfit dislocations in a 120 nm‐thick BiFeO3 film epitaxially grown on a thick substrate. With optimal contrast, the half‐widths at half‐maximum of the dislocation lines are 200 nm.
An X‐ray microscopy approach for mapping deeply embedded dislocations with a resolution of currently 200 nm is presented. The technique involves scanning an aperture in the back focal plane, which allows the strain fields around dislocations to be visualised with a strain resolution better than 10−4.
Increasing awareness of the importance of a healthy Bifidobacterium-rich microbiome has led to a need for more knowledge on how different prebiotic carbohydrates specifically impact the infant ...microbiome, especially as a community instead of single bacterial targets. In this study, we combined proton nuclear magnetic resonance (1H NMR) metabolomics and molecular biology methods for quantification of bacteria to compare the prebiotic effect of bovine milk oligosaccharides (BMO) and synthetic galacto oligosaccharides (GOS) using mono- and cocultures of eight major bacteria related to a healthy infant microbiome. The results revealed that BMO treatments supported growth of Bifidobacterium longum subsp. longum and Parabacteroides distasonis, while at the same time growth of Clostridium perfringens and Escherichia coli was inhibited. In addition, there was a synergistic effect of combining lactose and BMO in regards to reducing C. perfringens, maintaining stable numbers of P. distasonis and simultaneously increasing numbers of the beneficial B. longum subsp. longum. These results indicate that the oligosaccharide composition plays a vital role in shaping the developing microbiota.
The main purpose of this paper is the derivation and evaluation of various diffusion flux models. For this aim, a comprehensive catalyst pellet problem has been simulated for two test cases: the ...steam methane reforming (SMR) and the methanol synthesis, as these two important chemical processes cover various aspects of a chemical reaction. The pressure, temperature, total concentration, species composition, viscous flow, mass and heat fluxes within the porous spherical pellet are included in the transient pellet model. Mass diffusion fluxes are described according to the rigorous Maxell–Stefan and dusty gas models, and the respectively simpler Wilke and Wilke–Bosanquet models. Simulations are performed with these fluxes defined according to both the molar averaged and mass averaged definitions. For the mass based pellet equations, a consistent set of equations is obtained holding only the mass averaged velocity. On the other hand, the closed set of molar based pellet equations hold both the molar averaged and mass averaged velocities as the fundamental energy balance and the momentum balance (Darcy law) are derived according to the mass averaged velocity definition, whereas the diffusion fluxes are defined relative to the molar averaged velocity. Identical results of the molar and mass based pellet equations were not obtained; however, the deviations are small. It is anticipated that these discrepancies are due to some unspecified numerical inaccuracies. However, efficiency factors have been computed for both processes and the values obtained compare well with the available literature data. Furthermore, efficiency factor sensitivity on parameters like pore diameter, tortuosity, temperature and pressure have been accomplished, and the classical simplifications of the pellet equations have been elucidated: isothermal condition, constant pressure, and neglecting viscous flow. The following conclusions are established for the reactor operating conditions used in the present work.
The methanol synthesis: The simulation results of the methanol synthesis indicate that the classical assumptions are very fair for this process. Moreover, both Wilke and Wilke–Bosanquet models are good replacements for the more rigorous Maxwell–Stefan and dusty gas models. However, the simulation results are affected by Knudsen diffusion, thus the diffusion flux is most appropriately described by the Wilke–Bosanquet model.
The SMR process: Knudsen diffusion hardly influences the results of the highly intraparticle diffusion limited SMR process. As the Wilke model does not necessarily conserve mass, we recommend the Maxwell–Stefan model because the simpler Wilke closure deviates with several percents. However, it is not elucidated whether these deviations are numerical problems arising from the large gradients of this process, or related to the choice of diffusion model. Isothermal and isobaric conditions can be assumed within the particle, but significant external temperature gradients are observed. Convective fluxes are much less than the diffusive fluxes, hence viscous flow can be neglected.
Objective
Safety data regarding the use of etoricoxib and other nonsteroidal antiinflammatory drugs (NSAIDs) in ankylosing spondylitis (AS) and other spondyloarthritis (SpA) patients are rather ...limited. Our objective was to estimate and compare rates of gastrointestinal, renovascular, and cardiovascular adverse events in patients exposed to etoricoxib, celecoxib, or nonselective NSAIDs or totally unexposed to NSAIDs.
Methods
We performed a national register‐based cohort study on patients with AS or SpA (n = 21,872) identified in the Swedish national patient register from 1987–2009. Treatment exposure was assessed time dependently based on the prescription drug register from 2006–2009, adjusting for sociodemographics and comorbidities derived from national population‐based registers.
Results
Exposure to etoricoxib, celecoxib, and nonselective NSAIDs was 7.6%, 3.9%, and 71.2%, respectively. No major risk differences for serious cardiovascular, gastrointestinal, or renal adverse events were seen among the 3 exposure groups. Patients unexposed to NSAIDs had more baseline comorbidities and an increased relative risk for congestive heart failure events during the study period (2.0, 95% confidence interval 95% CI 1.3–3.2). The relative risk for atherosclerotic events was nonsignificant when compared to the nonselective NSAID group (1.0, 95% CI 0.7–1.5), while the relative risk for gastrointestinal events was lower for unexposed patients (0.5, 95% CI 0.4–0.7).
Conclusion
Overall, serious adverse events related to nonselective NSAIDs, etoricoxib, and celecoxib were similar and in the range of what would be expected in a group of SpA patients. Patients unexposed to NSAIDs had considerably more baseline comorbidities and increased risk for congestive heart failure, reflecting a selection of patients being prescribed NSAIDs in clinical practice.
Dark‐field X‐ray microscopy is a new full‐field imaging technique for nondestructively mapping the structure of deeply embedded crystalline elements in three dimensions. Placing an objective in the ...diffracted beam generates a magnified projection image of a local volume. By placing a detector in the back focal plane, high‐resolution reciprocal space maps are generated for the local volume. Geometrical optics is used to provide analytical expressions for the resolution and range of the reciprocal space maps and the associated field of view in the sample plane. To understand the effects of coherence a comparison is made with wavefront simulations using the fractional Fourier transform. Reciprocal space mapping is demonstrated experimentally at an X‐ray energy of 15.6 keV. The resolution function exhibits suppressed streaks and an FWHM resolution in all directions of ΔQ/Q = 4 × 10−5 or better. It is demonstrated by simulations that scanning a square aperture in the back focal plane enables strain mapping with no loss in resolution to be combined with a spatial resolution of 100 nm.
A method of high‐resolution reciprocal space mapping and strain scanning using the back focal plane in dark‐field X‐ray microscopy is introduced.
The paper presents a multi-fluid Eulerian model derived from binary kinetic theory of granular flows, free path theory and an empirical friction theory. The effects of the inter- and inner-particle ...collisions, particle translational motions and particle–particle friction are included. As the effects due to fluiddynamic particle velocity differences and particle–particle friction are considered, some unconventional terms are produced compared with the previous models. Model validation using the data from
Mathiesen et al. (2000) shows that the coupling terms give a stronger and more realistic particle–particle coupling because the effects due to the fluiddynamic velocity differences are considered. The model gives reasonable predictions of the particle volume fraction, particle velocities and velocity fluctuations. The model analysis reveals that the basic particle velocity fluctuations constitute 2 terms: the velocity fluctuations of the discrete particles, and the velocity fluctuations of the continuous fluid flow. Furthermore, the simulation results show that the velocity fluctuations of the continuous fluid flow are dominant in a binary riser flow.
This study investigated the predictive value of circulating microRNA-126 (cir-miRNA-126) in patients with metastatic colorectal cancer (mCRC) treated with first-line chemotherapy combined with ...bevacizumab.
The study included 68 patients. Blood samples (plasma) were collected before the treatment initiation, at the first clinical evaluation after 3 weeks and at progression. Levels of cir-miRNA-126 were determined by qRT-PCR after purification of total RNA from plasma. Primary clinical end points were response rates evaluated according to the Response Evaluation Criteria In Solid Tumours (RECIST) and progression-free survival (PFS).
Changes in circulating miRNA-126 during treatment were predictive of tumour response. Non-responding patients had a median increase in cir-miRNA-126 of 0.244 (95% confidence interval (CI), 0.050-0.565) compared with a median decrease of -0.374 (95% CI, -0.472 to -0.111) in the responding patients, P=0.002. A significant positive correlation was demonstrated by comparing the changes in tumour size with the changes in cir-miRNA-126, r=0.48, P=0.0001. Grouping the patients according to the changes in cir-miRNA-126 disclosed a borderline significant separation of the groups in the PFS analysis favouring patients with decreasing miRNA-126 levels, hazard ratio (HR) 0.60 (95% CI, 0.33-1.09), P=0.07.
The present results indicate that changes in cir-miRNA-126 during treatment are related to the response to chemotherapy and bevacizumab in patients with mCRC, thus representing a possible biomarker for the resistance to anti-angiogenic containing treatments.
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