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Lactic acid bacteria (LAB) can produce peptides known as bacteriocins with antagonistic activity against foodborne pathogens. The potential of LAB isolated from the surface of jalapeno peppers to produce bacteriocins with antagonistic activity against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella Typhimurium was evaluated. Previously isolated LAB strains were reactivated, and their cell-free supernatants (CFSs) were evaluated. Out of 390 reactivated strains, 60 produced bacteriocin-like inhibitory substances (BLIS) since their antagonistic activity was lost after proteases addition. Subsequently, 16 BLIS showed heat resistance (HR-BLIS), retaining their bioactivity after heat treatment (121 °C for 15 min). By 16S rRNA gene sequencing and antibiotic susceptibility tests, LAB strains producing HR-BLIS were identified as Enterococcus lactis. Four HR-BLIS exhibited a minimum inhibitory concentration (MIC) of 80 mg/mL against L. monocytogenes. MIC and minimum bactericidal concentration (MBC) of HR-BLIS-67 for S. aureus (MIC = 80 mg/mL; MBC = 320 mg/mL), S. Typhimurium (MIC = 150 mg/mL; MBC = 250 mg/mL), and E. coli O157:H7 (MIC = 250 mg/mL; MBC = 400 mg/mL) were determined. LAB isolated from the surface of jalapeno pepper produced HR-BLIS (possibly enterocin) that exhibited broad-spectrum antagonistic activity against foodborne pathogens; therefore, they are a promising source of natural antimicrobials to ensure food safety.

El Mangifera indica L., conocida generalmente como mango, es un producto demandado en el mundo y especialmente en Estados Unidos. El desconocimiento del posicionamiento comercial en el marco del t-mec del mango mexicano resulta una problemática significativa a estudiar, debido a la relevancia del producto. Se tiene como objetivo examinar la competitividad comercial del mango mexicano dentro del comercio estadounidense en el marco del t-mec, determinando tasas de crecimiento logarítmicas usando exportaciones, importaciones, índices de competitividad comercial y producción del mango de 1994 al 2020. Como metodología, se documentaron datos de producción, exportaciones e importaciones en toneladas y dólares. Se consultaron fuentes como Trademap, siap, usda y fao de 1994 al 2020 y se calcularon índices de competitividad comercial. Los resultados señalan que las exportaciones crecieron 361 %, las importaciones crecieron, pero continúan siendo poco significativas; los indicadores demostraron positividad general, el índice de la balanza comercial relativa fue cercano a 1, el índice de transabilidad fue de 0,13 en promedio, el grado de apertura exportadora fue positivo en dicho periodo y las importaciones presentaron en el grado de penetración valores cercanos a 0. Así, se concluye que la demanda de los Estados Unidos crece en mayor proporción que la oferta mexicana. A futuro, los aumentos de producción nacional serán absorbidos por el mercado estadounidense, por lo que se prevé un aumento significativo y sostenido de la competitividad.

Mild cooking thermal treatments, like sous-vide, can compromise ground meat entrees such as meatballs with chipotle sauce, especially when salt levels are reduced during its preparation. Listeria monocytogenes is a thermoresistant pathogen that can be in ready-to-eat food. On the other hand, nisin, due to its thermal stability, can be a good alternative to aid on the thermal inactivation of L. monocytogenes and ensure meat safety. The objective was to optimize the amount of nisin and salt concentrations to thermally inactivate L. monocytogenes during the sous-vide cooking of ground beef marinated in chipotle sauce, and to generate a predictive model. A four-strain cocktail was prepared and inoculated in ground beef in combination (3:2) with chipotle sauce added with nisin (0–150 IU) and salt (0–2%). After that, meat samples were sous-vide cooked at different temperatures, nisin, and salt concentrations, established by a central composite design. Depending on the levels of these factors, D-values ranged from 49.71 to 0.27 min. A predictive model (p

Photovoltaic solar energy has emerged in Brazil in distributed generation due to affordable costs and its application in different segments of the market. However, the electric energy storage in the photovoltaic systems is only viable for certain conditions in which the installation does not have access to the electricity network and the thermal portion of the solar energy is lost to the ambient. Heliothermic power plant represents another system available for solar electricity generation, which has higher costs, but takes better advantage of the portion of thermal energy and allows energy storage efficiently to meet the demands during periods without incident solar radiation. Heliothermic and photovoltaic generation have great potential in the Southeast and Northeast regions of Brazil, but the costs of both technologies cannot meet the demands during periods without solar radiation. This work presents a conceptual analysis of compound parabolic solar concentrators along with hybrid of photovoltaic and thermal collector systems to meet both the demand during sunlight hours and without solar radiation. The investigation consisted of implementing an organic Rankine cycle with different heliothermic plant configurations and the analysis of the diode model to examine different commercial photovoltaic cells operated in the Rankine cycle evaporation region. The results showed that the best working fluid for the application is R245fa with Urea-NaCl as molten salt for the thermal energy storage. The expected electrical power for the hydride cycle is 1580W at 2600 rpm and at 80°C of evaporation temperature, enabling a power generation for 1 hour and 20 min without solar radiation.

Water electrolysis cell in which the product gases was separated from liquid water on the surface of the electrode was developed. In order to realize the separation between gas and water, interdigitated diffusion layer (GDL) was designed, and the surface of the GDL was covered by catalyst to form electrode. When the pressurized water was supplied, the water directly made a contact to the proton conductive membrane. Due to the hydrophobic surface condition of the GDLs, gas/water separation along the surface of the electrode was completed.

Twitter is one of the most popular sources of information available on the internet. Thus, many studies have proposed tools and models to analyze the credibility of the information shared. The credibility analysis on Twitter is generally supported by measures that consider the text, the user, and the social impact of text and user. More recently, identifying the topic of tweets is becoming an interesting aspect for many applications that analyze Twitter as a source of information, for example, to detect trends, to filter or classify tweets, to identify fake news, or even to measure a tweet’s credibility. In most of these cases, the hashtags represent important elements to consider to identify the topics. In a previous work, we presented a credibility model based on text, user, and social credibility measures, and a framework called T-CREo, implemented as an extension of Google Chrome. In this paper, we propose an extension of our previous credibility model by integrating the detection of the topic in the tweet and calculating the topic credibility measure by considering hashtags. To do so, we evaluate and compare different topic detection algorithms, to finally integrate in our framework T-CREo, the one with better results. To evaluate the performance improvement of our extended credibility model and show the impact of hashtags, we performed experiments in the context of fake news detection using the PHEME dataset. Results demonstrate an improvement in our extended credibility model with respect to the original one, with up to 3.04% F1 score when applying our approach to the whole PHEME dataset and up to 9.60% F1 score when only considering tweets that contain hashtags from PHEME dataset, demonstrating the impact of hashtags in the topic detection process.

This study evaluated the water pollution of the El Pueblito River by employing physicochemical parameters and biological indicators. Monitoring was conducted weekly during three months at seven sampling sites. To ease the representation of the results of this analysis, the water quality index (WQI) was calculated. The results obtained by the physicochemical analysis show the same trends as those of the analyses performed with bioassays using Daphnia magna and the WQI. The obtained values showed a deterioration of water quality from upstream to downstream due to the discharges into the river that occurred as it went through the city of Corregidora. The WQI values shifted from good water quality (83.00 ± 7.40) upstream to poor water quality (27.00 ± 0.85) downstream. This study also shows the utility of the WQI and how a Daphnia magna toxicity test can be an affordable and fast tool used to indicate high levels of pollution, such as in the case of El Pueblito River.