Sensitivity of Penicillium expansum field isolates to tebuconazole, iprodione, fludioxonil and cyprodinil and characterization of fitness parameters and patulin production

A total of 236 Penicillium expansum field isolates from decayed apple fruit collected from packinghouses and processing industries located in the region of Imathia, Northern Greece were tested for their sensitivity to tebuconazole, fludioxonil, iprodione and cyprodinil. Preliminary fungitoxicity tests on the response of the isolates showed several phenotypes, distinguished according to their sensitivity to fungicides tested. The EC₅₀ values ranged from 0.64 to 5 (average = 0.98) μg/ml for iprodione, 0.9 to 7.3 (average = 2.66) μg/ml for tebuconazole, 0.008 to 1.28 (average = 0.55) μg/ml for cyprodinil and from 0.013 to 0.47 (average = 0.08) μg/ml for fludioxonil. A bimodal distribution of the EC₅₀ values of isolates with distinct sensitive and resistant populations to fludioxonil and tebuconazole were observed. In the case of cyprodinil, a much broader, hundred-fold, range of sensitivity was found, probably indicating that some isolates are relatively insensitive to cyprodinil compared to the most sensitive ones. Isolates exhibiting simultaneously reduced sensitivity to tebuconazole and fludioxonil or tebuconazole and iprodione or to tebuconazole and cyprodinil were also observed at low frequencies. A small portion of the population (7.5%) showed multiple resistance to tebuconazole, fludioxonil and iprodione. Study of fitness determining parameters showed that the resistance to tebuconazole, fludioxonil and iprodione had a significant adverse effect on mycelial growth rate and pathogenicity. Contrary to that, these fitness parameters were not affected in the isolates showing reduced sensitivity to cyprodinil. Analysis of patulin production on YES-agar growth medium and on artificially inoculated apple fruit showed that all isolates were mycotoxigenic. Most of the cyprodinil-insensitive isolates produced patulin at concentrations similar to or relatively higher (up to 1.5-fold on growth medium) than the sensitive ones. In contrast, a significant reduction (up to 98% of multiple resistant isolates) in patulin production was observed in all other phenotypes, indicating an adverse effect of fitness penalties on the mycotoxigenic ability of resistant isolates. The above mentioned data clearly show a considerable risk for the selection of P. expansum isolates resistant to fludioxonil, iprodione, tebuconazole and cyprodinil. The potential risk of increased patulin contamination of apples and their byproducts by the appearance and predominance of highly mycotoxigenic isolates of P. expansum resistant to the anilinopyrimidines is discussed.     

Sulfur infiltration and allotrope formation in porous cathode hosts for lithium-sulfur batteries

We investigate sulfur infiltration and formation of lower order allotropes in heated porous hosts during fabrication of lithium-sulfur (Li-S) battery cathodes. Sulfur existence in cathode ultramicropores has been an important question for Li-S batteries, as ultramicropores reduce the polysulfides “shuttle effect” but also delay sulfur dissolution and Li⁺ ion diffusion in the trapped solid sulfur. A novel continuum-level model is presented including heat transfer and sulfur infiltration, either from the top of a porous host or from the porous host particle surface, and taking into account the pore size distribution. A novel decay factor in modeling sulfur infiltration incorporates the pore wall repulsion energy and allotrope formation energy (predicted by density functional theory [DFT] simulations). Simulations are performed for a microporous carbon fabric host and an activated carbon powder host with bimodal micropore and macropore size distribution, with Raman and X-ray photoemission spectroscopy (XPS) spectroscopy confirming the predicted existence of linear S₆ and S₄ in ultramicropores.     

Assessing the performance of short multi-item questionnaires in aesthetic evaluation of websites

In recent years, website aesthetics has received a fair amount of attention from the HCI community. This has led to the creation of a variety of multi-item questionnaires aimed at capturing users’ aesthetic judgments. Researchers have used these questionnaires in several HCI studies to investigate the relationship between aesthetics and other evaluative constructs such as usability. However, their usefulness as evaluation tools in visual design practice remains underexplored. Lengthy multi-item questionnaires can be particularly problematic especially in studies where participants must evaluate multiple designs or when they are required to give responses repeatedly in predefined time intervals. Despite the criticism, single-item scales have been used in many past studies in which questionnaire length could be problematic. Another alternative available to practitioners/researchers are short versions of standardised multi-item questionnaires that have been created for the aesthetic evaluations of websites. In this paper, we present a study in which we compare the performance of three such condensed aesthetic questionnaires (i.e. aesthetics scale, AttrakDiff, VisAWI) during a website redesign project. The short versions of those questionnaires were used by 187 users during an evaluation of 7 alternative website designs. The questionnaires were compared on performance criteria such as reliability, validity, and predictive ability. Data analysis showed that although AttrakDiff’s overall performance was better, a considerable amount of variance in aesthetic judgment could not be accounted for by any of the questionnaires.     

Efficient algorithms for constructing broadcast disks programs in asymmetric communication environments

A well-known technique for broadcast program construction is the Broadcast Disks technique. However, in the Broadcast Disks approach there are some important disadvantages. For example some parts of the broadcast program remain empty during the construction procedure and the disk relative frequencies have to be selected very carefully. This paper gives a new approach of the broadcast program construction in a Broadcast Disk System, presenting three new algorithms, which face successfully these problems. According to this approach, the broadcast program is constructed with the minimum possible length, while retaining the selected disk relative frequencies and keeps the average delays on retrieving data-items low. The constructed broadcast programs have no empty parts, and retain their desired properties in any numbered combination of disk relative frequencies. We implemented all methods in a simulator application and experimental results show that our approach is more efficient than Broadcast Disks in all cases.     

Reengineering of the Laundry Service at a University Campus: A Continuous-Improvement Quality-Management Methodology

The Department of Auxiliary Services of the University of Miami had been the recipient of numerous anecdotal complaints by resident students regarding the service of the laundry system offered at the residential on-campus dormitories (students often complained about nonworking and/or busy machines). In this paper we present a holistic systems approach that utilizes total quality management and quantitative decision-making tools in a seamless fashion to improve the students' satisfaction and perception related to the laundry system. At the same time, other departmental important objectives, such as the implementation of an ongoing in-house procedure that supports its continuous-improvement program, are taken into account. Results that document the improved system performance are further presented.     

Noncontact optical imaging in mice with full angular coverage and automatic surface extraction

During the past decade, optical imaging combined with tomographic approaches has proved its potential in offering quantitative three-dimensional spatial maps of chromophore or fluorophore concentration in vivo. Due to its direct application in biology and biomedicine, diffuse optical tomography (DOT) and its fluorescence counterpart, fluorescence molecular tomography (FMT), have benefited from an increase in devoted research and new experimental and theoretical developments, giving rise to a new imaging modality. The most recent advances in FMT and DOT are based on the capability of collecting large data sets by using CCDs as detectors, and on the ability to include multiple projections through recently developed noncontact approaches. For these to be implemented, we have developed an imaging setup that enables three-dimensional imaging of arbitrary shapes in fluorescence or absorption mode that is appropriate for small animal imaging. This is achieved by implementing a noncontact approach both for sources and detectors and coregistering surface geometry measurements using the same CCD camera. A thresholded shadowgrammetry approach is applied to the geometry measurements to retrieve the surface mesh. We present the evaluation of the system and method in recovering three-dimensional surfaces from phantom data and live mice. The approach is used to map the measured in vivo fluorescence data onto the tissue surface by making use of the free-space propagation equations, as well as to reconstruct fluorescence concentrations inside highly scattering tissuelike phantom samples. Finally, the potential use of this setup for in vivo small animal imaging and its impact on biomedical research is discussed.     

Modeling and predicting spoilage of cooked, cured meat products by multivariate analysis

A cooked, cured meat product is a perishable product spoiled mainly by lactic acid bacteria (LAB). LAB cause discoloration, slime formation, off-odors and off-flavors as the result of their metabolic activity producing various products. These microbial products in conjunction with the microbial population could be used to assess the degree of spoilage of this type of product. The spoilage evaluation was achieved by following a multivariate approach. Cluster analysis, principal component analysis and partial least square regression were employed to associate spoilage with microbiological and physicochemical parameters. The developed model was capable of giving accurate predictions of spoilage describing the spoilage associations. The study might contribute to the improvement of quality assurance systems of meat enterprises.     

Functional properties of carotenoids originating from algae

Carotenoids are isoprenoid molecules which are synthesised de novo by photosynthetic plants, fungi and algae and are responsible for the orange, yellow and some red colours of various fruits and vegetables. Carotenoids are lipophilic compounds, some of which act as provitamins A. These compounds can be divided into xanthophylls and carotenes. Many macroalgae and microalgae are rich in carotenoids, where these compounds aid in the absorption of sunlight. Industrially, these carotenoids are used as food pigments (in dairy products, beverages, etc.), as feed additives, in cosmetics and in pharmaceuticals, especially nowadays when there is an increasing demand by consumers for natural products. Production of carotenoids from algae has many advantages compared to other sources; for example, their production is cheap, easy and environmentally friendly; their extraction is easier, with higher yields, and there is no lack of raw materials or limited seasonal variation. Recently, there has been considerable interest in dietary carotenoids with respect to their antioxidant properties and their ability to reduce the incidence of some chronic diseases where free radicals are involved. Possibly, carotenoids protect cells from oxidative stress by quenching singlet oxygen damage with various mechanisms. Therefore, carotenoids derived from algae could be a leading natural resource in the research for potential functional ingredients. Copyright © 2012 Society of Chemical Industry     

The microbiological condition of minced pork prepared at retail stores in Athens, Greece

Minced pork samples (n = 150) obtained from butchers' shops and supermarkets in Greece, during summer (n = 75) and winter (n = 75), were subjected to microbiological analysis. Microbial counts (log CFU/g) for the parameters tested were: total viable count (TVC), 6.8 ± 1.0; Pseudomonas spp., 6.4 ± 1.2; Brochothrix thermosphacta, 5.9 ± 1.1; lactic acid bacteria, 5.3 ± 1.0; yeasts and moulds, 4.6 ± 0.7; hydrogen sulfide (H(2)S)-producing bacteria, 4.3 ± 1.3; Enterobacteriaceae, 3.6 ± 1.2; total coliforms, 2.9 ± 1.1; Escherichia coli, 1.4 ± 0.7; Staphylococcus spp., 4.3 ± 1.0; S. aureus, 2.4 ± 0.9, and Listeria spp., 1.4 ± 0.6. The highest correlations were between TVC and pseudomonads, B. thermosphacta and H(2)S-producing bacteria, while the lowest were between total coliforms and all other groups of microorganisms except Enterobacteriaceae. The type of retail outlet and the seasonality of sampling did not have any significant effects (p>0.05) on minced pork meat quality. Interrelationships between (i) meat quality and shelf life, (ii) hygienic conditions during mince preparation and (iii) personnel hygiene were revealed.     

Bayesian inference for quantifying Listeria monocytogenes prevalence and concentration in minced pork meat from presence/absence microbiological testing

The purpose of this work was to estimate the prevalence and concentration of Listeria monocytogenes in minced pork meat by the application of a Bayesian modeling approach. Samples (n?=?100) collected from local markets were tested for L.?monocytogenes using in parallel the PALCAM, ALOA and RAPID'L.mono selective media. Presence of the pathogen was confirmed through biochemical and molecular tests. Independent experiments (n?=?10) for validation purposes were performed. No L.?monocytogenes was enumerated by direct-plating (<10?CFU/g), though the pathogen was detected in 22% of the samples. Sensitivity and specificity varied depending on the culture method. L.?monocytogenes concentration was estimated at 14-17?CFU/kg. Validation showed good agreement between observed and predicted prevalence (error?=?-2.17%). The use of at least two culture media in parallel enhanced the efficiency of L.?monocytogenes detection. Bayesian modeling may reduce the time needed to draw conclusions regarding L.?monocytogenes presence and the uncertainty of the results obtained.