A novel membrane-based lateral-flow immunodipstick assay was developed for the fast screening of aflatoxin B2 (AFB2) as a model compound in food samples. The detector reagent consisted of magnetic ...nanogold microspheres (MnGMs) with nano-Fe2O3 particles as core and gold nanoparticles as shell, and bio-functionalized with monoclonal anti-AFB2 antibodies. Manually spotted AFB2–bovine serum albumin conjugates (AFB2–BSA) and goat anti-mouse IgG on nitrocellulose membrane were used as test and control lines, respectively. As the major advantage, experimental results indicated that the visual detection limit (cutoff value) of the MnGM-based dipstick immunoassay with 0.9ng/ml AFB2 was about threefold lower compared to a conventional immunodipstick test using gold nanoparticles as detection reagent. Qualitative results (yes/no) could be obtained within 15min without expensive equipment. The assay was evaluated with AFB2 spiked or naturally contaminated samples (n=8), including peanuts, hazelnuts, pistacia and almonds, receiving excellent correspondance with results from high performance liquid chromatography (HPLC). Most importantly, the assay gave no false negative results. By controlling the target antibody this assay can be easily extended for use with other food relevant toxins and thus represents a versatile detection method.
Display omitted
ICME approaches provide decision support for materials design by establishing quantitative process-structure-property relations. Confidence in the decision support, however, must be ...achieved by establishing uncertainty bounds in ICME model chains. The quantification and propagation of uncertainty in computational materials science, however, remains a rather unexplored aspect of computational materials science approaches. Moreover, traditional uncertainty propagation frameworks tend to be limited in cases with computationally expensive simulations. A rather common and important model chain is that of CALPHAD-based thermodynamic models of phase stability coupled to phase-field models for microstructure evolution. Propagation of uncertainty in these cases is challenging not only due to the sheer computational cost of the simulations but also because of the high dimensionality of the input space. In this work, we present a framework for the quantification and propagation of uncertainty in a CALPHAD-based elastochemical phase-field model. We motivate our work by investigating the microstructure evolution in Mg2SixSn1−x thermoelectric materials. We first carry out a Markov Chain Monte Carlo-based inference of the CALPHAD model parameters for this pseudobinary system and then use advanced sampling schemes to propagate uncertainties across a high-dimensional simulation input space. Through high-throughput phase-field simulations we generate 200,000 time series of synthetic microstructures and use machine learning approaches to understand the effects of propagated uncertainties on the microstructure landscape of the system under study. The microstructure dataset has been curated in the Open Phase-field Microstructure Database (OPMD), available at http://microstructures.net.
We report on scaling, rotation, and channeling behavior of helical and skyrmion spin textures in thin films of Te-doped Cu
2
OSeO
3
.
Topologically nontrivial spin textures such as vortices, ...skyrmions, and monopoles are promising candidates as information carriers for future quantum information science. Their controlled manipulation including creation and annihilation remains an important challenge toward practical applications and further exploration of their emergent phenomena. Here, we report controlled evolution of the helical and skyrmion phases in thin films of multiferroic Te-doped Cu
2
OSeO
3
as a function of material thickness, dopant, temperature, and magnetic field using in situ Lorentz phase microscopy. We report two previously unknown phenomena in chiral spin textures in multiferroic Cu
2
OSeO
3
: anisotropic scaling and channeling with a fixed-Q state. The skyrmion channeling effectively suppresses the recently reported second skyrmion phase formation at low temperature. Our study provides a viable way toward controlled manipulation of skyrmion lattices, envisaging chirality-controlled skyrmion flow circuits and enabling precise measurement of emergent electromagnetic induction and topological Hall effects in skyrmion lattices.
Actualmente las redes viales en zonas urbanas sufren obstrucciones, ya sea por manifestaciones, embotellamientos, u otro tipo de bloqueo, causando el cierre momentáneo o permanente de vías o zonas de ...tránsito que obligan a conductores a establecer nuevas rutas. Una solución es la creación de rutas alternativas en mapas digitales a partir de dígrafos relacionados con las características de una red vial real, y la aplicación de algoritmos de optimización de rutas. En este trabajo se propone un método para construir dígrafos con una aplicación en la API de Google Maps en la extracción visual de elementos como vértices (intersecciones), aristas (calles) y flechas de sentido (dirección vial), lo que permite la aplicación del algoritmo de Dijkstra en busca de rutas alternativas.
The increase in the consumption of fresh produce has correlated with a rise in the number of reported foodborne illnesses. To identify potential risk factors associated with postharvest practices, ...the present study employed multilocus sequence typing (MLST) for the genotypic classification of Escherichia coli isolates recovered from three sources sampled at seven operational stages in a cantaloupe packinghouse in Northwestern Mexico. The MLST analysis results indicated that the E. coli isolates were classified into 18 different sequence types (ST), and 11 of these STs were found to be novel. ST‐171 was the predominant type and was found in 19% (7/36) of the recovered isolates. Interestingly, the novel ST‐827 was found to be significantly associated with isolates recovered from workers’ hands, sampled during final postwash stages. Further phylogenetic analyses to examine the relatedness of the STs revealed genetic heterogeneity. Fourteen of the identified STs were assigned to known clonal groups, while the remaining four novel STs were distinct and did not cluster with any clonal group. The present study has provided the first evidence indicating that several sources from distinct operational stages in a cantaloupe packinghouse may contribute to a genotypic and phylogenetic diverse set of E. coli isolates.
Significance and Impact of the Study
Packinghouses can be considered as a potential source of microbial contamination. Using multilocus sequence typing, this study identified a genotypic and phylogenetic diverse set of Escherichia coli isolates recovered from the surfaces of cantaloupes, workers’ hands and processing equipment at a cantaloupe packinghouse. A total of 61% of the sequence types identified were novel, and a distinct sequence type, ST‐827, was significantly associated with worker's hands, sampled during the final postwash operational stages in the packinghouse. These findings serve as a baseline to identify potential sources of microbial contamination at distinct operational stages in a cantaloupe packinghouse.
Significance and Impact of the Study: Packinghouses can be considered as a potential source of microbial contamination. Using multilocus sequence typing, this study identified a genotypic and phylogenetic diverse set of Escherichia coli isolates recovered from the surfaces of cantaloupes, workers’ hands and processing equipment at a cantaloupe packinghouse. A total of 61% of the sequence types identified were novel, and a distinct sequence type, ST‐827, was significantly associated with worker's hands, sampled during the final postwash operational stages in the packinghouse. These findings serve as a baseline to identify potential sources of microbial contamination at distinct operational stages in a cantaloupe packinghouse.
We have measured the doping and temperature dependence of lattice vibrations and magnetic excitations in the prototypical doped spin-orbit Mott insulator Sr2−xLaxIrO4 (x=0, 0.015, and 0.10). Our ...findings show that the pseudospin-lattice coupling-responsible for the renormalization of several low energy phonon modes-is preserved even when long-range magnetic order is suppressed by doping. In our most highly doped sample, the single magnon (Γ point) excitation disappears while the two-magnon mode softens and becomes heavily damped. Doping-induced electron-phonon coupling is also observed in a higher energy phonon mode. We observe two different electron-phonon interaction channels, which provide evidence of the coexistence of fluctuating magnetic moments and mobile carriers in doped iridates.
This work addresses the physicochemical, enzymatic and sensory changes in cloudy apple juice treated by ultra-high pressure homogenization (UHPH) and short-wave ultraviolet radiation (UV–C) applied ...at 20 °C. Those technologies were applied in single and combined treatments at different UHPH pressures (200–300 MPa) and UV-C doses (14.3–27.8 J/mL). UV-C treatments could not effectively inactivate enzymes, but treatments at 300-MPa UHPH reduced pectin methylesterase activity to a 24.6%, and polyphenol oxidase activity was not detected. Those samples presented a higher antioxidant capacity (283% measured by FRAP, and 286.4% by DPPH) than in non-treated juice, and after a combination with 28.7 J/mL of UV-C the polyphenols content augmented to 277.6%. Sensory evaluation revealed that UHPH at 300 MPa and UV-C at 21.5 J/mL significantly changed perceptible odour and overall flavour of cloudy apple juice, while treatments at 200 MPa didn't produce any significant changes in the different parameters. The results obtained in this study give a promising perspective of what a combination of both technologies can bring about in terms of obtaining stabilized fruit juices with improved antioxidant activity and polyphenol availability.
•UHPH at 300 MPa highly contributes to better cloudiness in apple juice with fibre.•Polyphenol oxidase activity was not detected after 300-MPa UHPH.•Pectin methylesterase activity was greatly reduced after 300-MPa UHPH.•Antioxidant capacity and polyphenols improved after 300-MPa UHPH.•Flavour changes were found in apple juice treated by UHPH and UV-C.
Lethality rates of Bacillus subtilis, Geobacillus stearothermophilus, Alicyclobacillus acidoterrestris, and Aspergillus niger spores were studied into phosphate-buffer saline (PBS) and PBS ...supplemented with caramel (PBSC) after Ultra-High Pressure Homogenization (UHPH) and UV-C treatments applied separately and combined. UHPH procedures were carried out at different pressures (100, 200 and 300 MPa) and inlet temperatures (20, 50 and 70 °C), while UV-C treatments consisted in a combination of doses (from 0.9 to 21.5 J/mL) and eventually temperatures (20 and 50 °C) or cycles. UHPH treatments were efficient at inactivating A. niger conidiospores in PBS but much less efficient in the inactivation of bacterial spores. Efficacy of UHPH against bacterial spores was increased pre-heating the samples at 70 °C. UV-C was more efficient against bacterial spores in PBS, but much less in PBSC. When UV-C treatments were applied through several cycles their efficacy against B. subtilis spores increased. Combination of UHPH at 200 MPa and UV-C moderately increased the lethal effect on B. subtilis spores than when these treatments were applied separately. Nevertheless, the combination of both technologies has a complementary effect allowing acting on a wide range of microorganisms, increasing the possibilities to obtain a safer and durable product.
•UV-C inactivation varies with the absorbance of the matrix and type of microorganism.•UV-C inactivation increases in cycles with more number of passes of the matrix through the reactor.•UHPH is an effective technology for the inactivation of Aspergillus niger.•The combination of UHPH and UV-C technologies is a promising alternative for obtaining stable food products.
This work addresses the use of a thin-film short wave ultraviolet radiation (UVC) reactor and its combination with ultra-high pressure homogenization (UHPH) for the inactivation of Talaromyces ...macrosporus (CBS 130.89) and Neosartorya spinosa (CBS 586.90), fungal species that can cause food spoilage in products made of fruits. Ascospores of these microorganisms were inoculated in phosphate buffer solution (PBS) and clarified apple juice at a concentration between 5 and 6 Log10 spores/mL before treatments. Ascospores of both microorganisms were not detected in PBS after UV-C treatments even at the lowest assayed dose (1.8 J/mL), but in apple juice T. macrosporus showed to be significantly more UV-C resistant than N. spinosa. A UV-C dose of 21.5 J/mL in a single pass achieved decimal reductions of 2.15 Log10 and 5.4 Log10 respectively. Decimal reductions of both strains significantly increased in many cases when the same UV-C dose was applied in 2 or 3 passes throughout the UV-C reactor achieving T. macrosporus a maximum reduction of 3.88 Log10 after a UV-C dose of 21.5 J/mL applied in 3 passes. UHPH treatments at 100 and 200 MPa were ineffective in inactivating ascospores of both microorganisms, However, UHPH left ascospores more vulnerable to UV-C resulting in a synergistic effect achieving a maximum reduction of 3.6 Log10 on T. macrosporus after a combined treatment of UHPH at 200 MPa and a single pass of UV-C at 21.5 J/mL. The use of scanning electron microscopy revealed that only UHPH caused small changes in the cell wall structure of ascospores, but that might have left cells better exposed to UV-C.
•Talaromyces macrosporus and Neosartorya spinosa ascospores are vulnerable to UV-C.•T. macrosporus was more UV-C resistant than N. spinosa in apple juice.•UHPH at 200 MPa did not inactivate ascospores but made them more vulnerable to UV-C.•UHPH and UV-C have a synergic effect on T. macrosporus and N. spinosa ascospores.•Ascospores were not inactivated at 200 MPa of UHPH but improved the effect of UV-C.
PDF
