411 research outputs found
A review on the development of visible light-responsive WO3-based photocatalysts for environmental applications
The use of semiconductor photocatalysis is a promising, green, and sustainable technology to address solar energy conversion and environmental remediation issues. Among photocatalytically active semiconductors, considerable attention has been given to the visible-light active tungsten oxide (WO3, Eg value ≈ 2.7–3.1 eV). This
semiconductor has several advantages: strong absorption in the visible spectrum range, stability in acidic and
oxidative conditions, low cost, and low toxicity. However, WO3 presents fast recombination of charge carriers’
and exhibits low photocatalytic activity for reduction reactions due to its conduction band potential (+0.5 V versus NHE). Many strategies have been applied to enhance photocatalytic activity and solar energy utilization of
WO3 by modifying the energy band position and reducing the charge carrier recombination. In this review, several approaches, such as designing with exposed facets and specific morphologies, doping with transition metals
and non-metals, deposition of noble metals, and heterojunction construction, are summarized.
Moreover, the photocatalytic properties of the reviewed WO3-based photocatalysts are discussed based on their
environmental applications such as degradation of organic pollutants, air purification, CO2 photoreduction, hydrogen production from water splitting and recently, simultaneous wastewater treatment and electric energy generation by photocatalytic fuel cells. Finally, the summary, future perspectives, and challenges of design novel WO3-based photocatalysts with high efficiency are pointed out to meet the urgent demands of highly efficient technologies that use visible or solar energy for environmental applications
Solar photocatalytic degradation of polyethylene terephthalate nanoplastics: Evaluation of the applicability of the TiO2/MIL-100(Fe) composite material
For the first time, TiO2/MIL-100(Fe) photocatalysts supported on perlite mineral particles prepared by the solvothermal/microwave methods and post-annealing technique were tested in the degradation of polyethylene terephthalate nanoplastics (PET NPs). Powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, N2 physisorption, photoluminescence emission spectroscopy, photocurrent response, and electrochemical impedance spectroscopy were used to characterize the as-prepared materials. The response surface methodology approach was used to study the effects: pH of the NPs suspension and incorporated amount of MIL-100(Fe) on the TiO2/MIL-100(Fe) catalyst to optimize the photocatalytic degradation of the PET NPs under simulated solar light. The degradation of the PET NPs was evaluated by measuring turbidity and carbonyl index (FTIR) changes. The total organic carbon (TOC) in the solution during the degradation of the PET NPs was assessed to measure NPs oxidation into water-soluble degradation by-products. The active species involved in the photocatalytic degradation of PET NPs by the TiO2/MIL-100(Fe) composite was further examined based on trapping experiments. The use of 12.5 wt% TiO2/MIL-100(Fe) catalyst showed improved photocatalytic efficacy in the oxidation of PET NPs at pH 3 under simulated sunlight compared to bare TiO2. The increase in the carbonyl index (CI = 0.99), the reduction in the turbidity ratio (0.454), and the increase in the content of TOC released (3.00 mg/L) were possible with 12.5 wt% TiO2/MIL-100(Fe) material. In contrast, the PET NPs were slowly degraded by TiO2-based photocatalysis (CI = 0.96, turbidity ratio = 0.539, released TOC = 2.12 mg/L). The mesoporous TiO2/MIL-100(Fe) composites with high specific surface area, capacity to absorb visible light, and effective separation of photogenerated electron-hole charges clearly demonstrated the enhancement of the photocatalytic performance in the PET NPs degradation under simulated solar light
Flavonoid and Capsaicinoid Contents and Consumption of Mexican Chili Pepper (Capsicum annuum L.) Landraces
There is insufficient evidence to identify the precise health effects of chili pepper consumption. However, there is evidence of their topical use as an analgesic to decrease pain from rheumatoid arthritis, osteoarthritis, neuralgias, neuropathic diabetes, neuronal dysfunctions and inflammation, among others. In this work, the diversity and variety of consumed forms of chilis in Mexico, flavonoid and capsaicinoid content in fruits, and their potential health uses are documented, based on various research results and bibliographic information. In Mexico, more than 150 landraces of wild and cultivated origins are consumed and preserved and are distributed throughout the country; the greatest diversity is concentrated in the central and south-southeastern regions. Consumption per capita in urban households is from 8 to 9 kg, and in rural communities, it varies from 14 to 17 kg. Chili peppers contain up to 23 flavonoids and 20 capsaicinoids, differing among landraces because of crop management, maturation of fruits, postharvest management and ecological-environmental influences. Flavonoids and capsaicinoids confer antioxidant, anticarcinogenic properties on the fruit and have lipolytic and preventative effects on chronic degenerative diseases. However, in vitro and in vivo experimental trials of capsaicinoids and flavonoids with beneficial effects must be conducted with regard to human health
Specific Gene Loci of Clinical Pseudomonas putida Isolates
Pseudomonas putida are ubiquitous inhabitants of soils and clinical isolates of this species have been seldom described. Clinical isolates show significant variability in their ability to cause damage to hosts because some of them are able to modulate the host’s immune response. In the current study, comparisons between the genomes of different clinical and environmental strains of P. putida were done to identify genetic clusters shared by clinical isolates that are not present in environmental isolates. We show that in clinical strains specific genes are mostly present on transposons, and that this set of genes exhibit high identity with genes found in pathogens and opportunistic pathogens. The set of genes prevalent in P. putida clinical isolates, and absent in environmental isolates, are related with survival under oxidative stress conditions, resistance against biocides, amino acid metabolism and toxin/antitoxin (TA) systems. This set of functions have influence in colonization and survival within human tissues, since they avoid host immune response or enhance stress resistance. An in depth bioinformatic analysis was also carried out to identify genetic clusters that are exclusive to each of the clinical isolates and that correlate with phenotypical differences between them, a secretion system type III-like was found in one of these clinical strains, a determinant of pathogenicity in Gram-negative bacteria.Work in the authors’ laboratories was supported by ERANET Pathogenomics programme through the ADHERS project (Ref: BIO2008-04419-E) and Fondos FEDER from the European Union through project BIO2010-17227 of the Ministry of Economy and Competitivity of Spain. Bio-Iliberis R&D provided supportPeer reviewe
Recursos y estrategias para la enseñanza de la estadística y la analítica de datos en la educación superior
The purpose of this study is to present a literature review analysis on the teaching of statistics and data
analytics in higher education. The assessment includes examining the role played by specific factors as
mediators of teaching-learning processes. These factors include: disciplinary and pedagogical training of
teachers, teaching styles, classroom experiences, use of didactic resources, and context. The literature review
revealed that there is a need to create and develop innovative learning environments that transform the
teaching of statistics at the university level, starting from rethinking the contents and curricula to favor the
social dimension and the humanistic and complex thinking of students. It is concluded that, currently, the
generalization of digital media and social networks imposes new challenges for teaching statistics and data
analytics in the context of data science, machine learning, and big data.El propósito de este estudio es presentar una reflexión documentada frente a la enseñanza de la estadística
y la analítica de datos en la educación superior. Se analiza el papel que cumplen factores como la formación
disciplinar y pedagógica de los docentes, sus estilos de enseñanza, las experiencias en el aula de clase, el
uso de recursos didácticos y el contexto, como mediadores de los procesos de enseñanza-aprendizaje. Como
resultado de la referenciación de autores realizada, se expone frente a la necesidad de crear y desarrollar
ambientes de aprendizaje innovadores que transformen la enseñanza de la estadística a nivel universitario, a
partir de repensar los contenidos y currículos para favorecer la dimensión socio humanística y el pensamiento
complejo de los estudiantes. Se concluye que actualmente la generalización de medios digitales y las redes
sociales constituyen un nuevo reto para la enseñanza de la estadística y la analítica de datos en su integración
con ciencia de datos, aprendizaje automático y macrodatos
Desarrollo de la colección de publicaciones periódicas en una biblioteca especializada o centro de documentación
The purpose of this paper is to study the basic serials for a specialised library, in this case in Life Science. The methods we made use of can be applied to serials in any subject and consisted in access, consult, comparison and analysis of the difTerent specialised databases, both in CD-ROM support and in printed or magnetic support. A list of indexed titles was extracted from these databases and a comparison, confrontation and analysis took place. Finally, the list of seríais obtained was compared with the Journal Citation Reports in arder to analyze the proximity of both lists.El objetivo de este trabajo es hacer una selección de las publicaciones periódicas básicas que una biblioteca especializada debe contener, en este caso en el área de Biomedicina. La metodología empleada es aplicable a publicaciones periódicas de cualquier campo temático y consistió en el acceso, consulta, comparación y análisis de las distintas bases de datos especializadas, tanto en soporte CD-ROM, como impreso o magnético. Se extrajo una lista de títulos indizados por estas bases de datos y se procedió a la comparación, confrontación y análisis de los títulos obtenidos. La selección de revistas obtenida se comparó con la del Journal Citation Reports para analizar en qué medida se aproximan ambos listados
Bactrospora totonacae (Arthoniales, Ascomycota), una nueva especie de Veracruz, México
Background and Aims: Bactrospora is a genus of crustose lichens characterized by its black, verrucose to denticulate and little apothecia, and mostly acicular, or sometimes muriform spores, longer than wide. The genus is represented by 38 accepted species. The aim of this work is to describe Bactrospora totonacae, a new species from the tropical dry forest of Veracruz, Mexico. Methods: The specimens were collected on the “Cerro de los Metates” in the municipality of Actopan, Veracruz, Mexico. Macrochemical tests, UV reaction, and a thin layer chromatography were performed; likewise, the presence of amyloid substances distributed in the thallus and ascomata was verified with Lugol’s solution. The voucher is deposited in the herbarium XALU of the Facultad de Biología of the Universidad Veracruzana. Key results: The new species Bactrospora totonacae is characterized by the pruine K+ reddish magenta in its disc. Conclusions: The described species is unique in Bactrospora because the combination of pruine K+ reddish magenta and a thick carbonized exciple has never been reported in this genus.Antecedentes y Objetivos: Bactrospora es un género de líquenes costrosos que se caracteriza por el color negro, aspecto verrucoso a denticulado y pequeño de sus apotecios, posee esporas mayoritariamente aciculares y en ocasiones muriformes, pero siempre más largas que anchas. El género está representado por 38 especies aceptadas. El objetivo de este trabajo es describir Bactrospora totonacae, una especie nueva del bosque tropical seco de Veracruz, México.Métodos: Los especímenes fueron recolectados en el “Cerro de los Metates”, municipio Actopan, Veracruz, México. Se realizaron pruebas macroquímicas, reacción UV y cromatografía en capa fina; asimismo, con la solución de Lugol se verificó la presencia de sustancias amiloides distribuidas en el talo y el ascoma. Las muestras estudiadas se depositaron en el herbario XALU de la Facultad de Biología de la Universidad Veracruzana.Resultados clave: La nueva especie Bactrospora totonacae se caracteriza por presentar pruina K + magenta rojizo en el disco.
Conclusiones: La especie que se describe en Bactrospora es única porque la combinación de pruina K + magenta rojizo y un excípulo carbonizado y grueso no había sido reportada en alguna otra especie de este género
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