Epoxiconazole degradation in water samples: a comparative study of Fenton, photo-Fenton, solar photo-Fenton, and solar photolysis processes.

Epoxiconazole (EPO) is classified as a persistent organic pollutant due to its ability to persist in the environment for prolonged periods. Its degradation is pivotal in mitigating its environmental impact. This investigation focuses on assessing the degradation of EPO using various methodologies, namely Fenton, photo-Fenton, solar photo-Fenton, and solar photolysis, conducted in both Milli-Q water and groundwater. These experiments encompassed evaluations at both the standard pH typically used in photo-Fenton reactions and the natural pH levels inherent to the respective aqueous environments. Additionally, EPO degradation products were analyzed after a 60-min reaction. Notably, in systems utilizing groundwater, the inclusion of additional iron was unnecessary, as the naturally occurring iron content in the groundwater facilitated the intended processes. Specifically, in Milli-Q water, solar photo-Fenton demonstrated an EPO degradation efficiency of 97%. Furthermore, the substitution of Milli-Q water with groundwater in Fenton-like processes did not significantly affect the efficacy of EPO degradation. These findings underscore the potential of solar photo-Fenton as an economically viable and environmentally sustainable strategy for EPO degradation.

A novel eco-friendly polymeric photosensitizer based on chitosan and flavin mononucleotide.

Flavin mononucleotide (FMN) is a dye belonging to the flavin family. These dyes produce photosensitized degradation of organic compounds via reaction with the excited states of the dye or with reactive oxygen species photogenerated from the triplet of the dye. This article presents a new polymeric dye (FMN-CS) composed of the photosensitizer FMN covalently bonded to chitosan polysaccharide (CS). FMN-CS obtained has a molecular weight of 230 × 103 g mol-1 and a deacetylation degree of 74.8%. The polymeric dye is an environmentally friendly polymer with spectroscopic and physicochemical properties similar to those of FMN and CS, respectively. Moreover, under sunlight, it is capable of generating 1O2 with a quantum yield of 0.31. FMN-CS, like CS, is insoluble in basic media. This allows easy recovery of the polymeric dye once the photosensitized process has been carried out and makes FMN-CS a suitable photosensitizer for the degradation of pollutants in contaminated waters. To evaluate whether FMN-CS may be used for pollutant degradation, the photosensitized degradation of two trihydroxybenzenes by FMN-CS was studied.

Photocatalytic evaluation and characterization of TiO2-riboflavin phosphate film: analysis of reactive oxygen species.

The effect of Riboflavin-5'-phosphate (RFPO4) sensitization on photocatalytic properties of TiO2 film was studied. RFPO4 was adsorbed on film surface to investigate the photophysical properties of TiO2 upon blue-light photoexcitation. The film was characterized through scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and diffuse reflectance spectroscopy. The efficiency of the TiO2/RFPO4 film was tested for pollutant elimination in aqueous media in a visible-light-driven system. The phenol paradigmatic model was employed in an aqueous solution as a contaminant target. TiO2/RFPO4 sensitized photodegradation of phenol, which produces catechol, hydroquinone, and benzophenone, was monitored by absorption spectroscopy and HPLC. The results indicated that phenol degradation with TiO2/RFPO4 film was due to the photogeneration of two reactive oxygen species, singlet molecular oxygen (O2(1Δg)) and superoxide radical anion (O2·-) identified through specific detection techniques. The presence of O2(1Δg) is reported here for the first time as generated from a sensitized TiO2 film upon visible-light photoirradiation. Based on the photophysical determinations, a photocatalytic mechanism for TiO2/RFPO4 was established.

Movilización del conocimiento: aportes para los estudios sociales de la salud / Knowledge Mobilization: Contributions for Social Studies in Health / Mobilização do conhecimento: aportes para os estudos sociais da saúde

Resumen Introducción: Las brechas entre la investigación en salud y su aplicación práctica constituyen un objeto de estudio y un campo de intervención en la esfera sanitaria. La traducción y uso del conocimiento basado en investigación se consideran cruciales para mejorar la salud pública y los sistemas de salud. Desarrollo: El objetivo de este trabajo es revisar y comparar los enfoques conceptuales investigación traslacional (trans-lational research), traslación del conocimiento (knowledge translation) y movilización del conocimiento (knowledge mobilization). Estos enfoques se han desarrollado teórica e institucionalmente en países con fuertes sistemas de investigación en salud, como Estados Unidos, Canadá y Reino Unido, mientras que en Latinoamérica han sido poco trabajados. Se identifican sus objetivos, concepción de los procesos de transferencia de conocimiento, principales aportes y limitaciones. El enfoque movilización del conocimiento en salud se destaca como una propuesta más amplia, que aborda el carácter social de la producción, transferencia y uso del conocimiento. Conclusiones: El enfoque de movilización de conocimiento puede ser un marco útil para el estudio y sistematización de experiencias sobre el uso del conocimiento en salud en la región latinoamericana, a fin de fortalecer los sistemas nacionales de investigación en salud.

Abstract Introduction: The gaps between health research and its practical application constitute an object of study and a field of intervention in the health sphere. The translation and use of research-based knowledge are considered crucial to improve public health and health systems. Development: The aim of this paper is to review and compare the conceptual approaches translational research, knowledge translation, and knowledge mobilization. These approaches have been theoretically and institutionally developed in countries with strong health research systems such as the United States, Canada, and the United Kingdom, while in Latin America, they have not been sufficiently studied. To analyze the knowledge transfer processes conception and their main contributions and limitations. The knowledge mobilization approach stands out as a wider framework, which includes the social nature of the production, transfer, and use of knowledge. Conclusions: The knowledge mobilization approach is a suitable framework for studying and systematizing experiences on the use of health knowledge in Latin America, aiming at strengthening National Health Research Systems.

Resumo Introdução: As brechas entre a pesquisa em saúde e a sua aplicação prática constituem um objeto de estudo e um campo de intervenção na esfera sanitária. A tradução e uso do conhecimento baseado em pesquisa consideram-se cruciais para melhorar a saúde pública e os sistemas de saúde. Desenvolvimento: O objetivo deste trabalho é revisar e comparar os enfoques conceituais pesquisa translacional (translational research), translação do conhecimento (knowledge translation) e mobilização do conhecimento (knowledge mobilization). Estes enfoques se têm desenvolvidos teórica e institucionalmente em países com fortes sistemas de pesquisa em saúde, como os Estados Unidos, a Canadá, e o Reino Unido enquanto na Latino-América têm sido pouco trabalhados. Se identificam seus objetivos, concepção dos processos de transferência de conhecimento, principais aportes e limitações. O enfoque mobilização do conhecimento em saúde destaca-se como uma proposta mais ampla, que aborda o carácter social da produção, transferência e uso do conhecimento. Conclusões: O enfoque de mobilização do conhecimento pode ser um marco útil para o estudo e sistematização de experiências sobre o uso do conhecimento em saúde na região latino-americana, com o objetivo de fortalecer os sistemas nacionais de pesquisa em saúde.

Photo-Fenton and Riboflavin-photosensitized Processes of the Isoxaflutole Herbicide.

The proherbicide Isoxaflutole (IXF) hydrolyzes spontaneously to diketonitrile (DKN) a phytotoxic compound with herbicidal activity. In this work, the sensitized degradation of IXF using Riboflavin (Rf), a typical environmentally friendly sensitizer, Fenton and photo-Fenton processes has been studied. The results indicate that only the photo-Fenton process produces a significant degradation of the IXF. Photolysis experiments of IXF sensitized by Riboflavin is not a meaningful process, IXF quenches the Rf excited triplet (3 Rf*) state with a quenching rate constant of 1.5 · 107  m-1  s-1 and no reaction is observed with the species O2 (1 Δg ) or O 2 · - generated from 3 Rf*. The Fenton reaction produces no changes in the IXF concentration. While the photo-Fenton process of the IXF, under typical conditions, it produces a degradation of 99% and a mineralization to CO2 and H2 O of 88%. A rate constant value of 1.0 × 109  m-1  s-1 was determined for the reaction between IXF and HO˙. The photo-Fenton process degradation products were identified by UHPLC-MS/MS analysis.

Diabetes research in Mexico: a map of 13 years of public funding.

In Mexico, diabetes represents a serious public health problem and a high-cost disease for the health system. Health research is essential for generating new knowledge to combat such a serious issue, however, there is not enough information on how to generate and use it. This paper examines the public funding of 303 diabetes research projects, granted by the National Council of Science and Technology in Mexico between 2002 and 2014. The projects were systematized and classified according to their type of research, discipline or subject, and aim of knowledge. Considering these information, an econometric model that links the funding with the characteristics of the projects was prepared. The results show that the funding is focused on the basic and biomedical areas, particularly on genetic research, and also that diabetes research resources have increased over time, not steadily, but rather cyclically. In diabetes research projects there is a high level of concentration at several dimensions: research areas, topics, objects, institutions conducting research, and regions. The analysis of the resource allocation suggests that Mexico needs a stronger and oriented diabetes research agenda, including in its bases discussions about balance between basic and applied research, and about oriented research towards practical implementations. The importance of promoting health systems research to improve diabetes care is also discussed, as well as implementing mechanisms to assess the impact of diabetes research in short, medium and long term, as part of Mexico's science and technology policy.

Diabetes research in Mexico: a map of 13 years of public funding / La investigación en diabetes en México: un mapa de 13 años de financiamiento público / Pesquisa em diabetes no México: um mapa de 13 anos de financiamento público

Abstract: In Mexico, diabetes represents a serious public health problem and a high-cost disease for the health system. Health research is essential for generating new knowledge to combat such a serious issue, however, there is not enough information on how to generate and use it. This paper examines the public funding of 303 diabetes research projects, granted by the National Council of Science and Technology in Mexico between 2002 and 2014. The projects were systematized and classified according to their type of research, discipline or subject, and aim of knowledge. Considering these information, an econometric model that links the funding with the characteristics of the projects was prepared. The results show that the funding is focused on the basic and biomedical areas, particularly on genetic research, and also that diabetes research resources have increased over time, not steadily, but rather cyclically. In diabetes research projects there is a high level of concentration at several dimensions: research areas, topics, objects, institutions conducting research, and regions. The analysis of the resource allocation suggests that Mexico needs a stronger and oriented diabetes research agenda, including in its bases discussions about balance between basic and applied research, and about oriented research towards practical implementations. The importance of promoting health systems research to improve diabetes care is also discussed, as well as implementing mechanisms to assess the impact of diabetes research in short, medium and long term, as part of Mexico's science and technology policy.

Resumen: En México la diabetes es un grave problema de salud pública y es una enfermedad de alto costo para el sistema de salud. La investigación en salud es esencial para generar nuevo conocimiento para combatir este problema, pero existe escasa información sobre su generación y uso. Este trabajo examina el financiamiento público de 303 proyectos de investigación sobre diabetes, otorgados por el Consejo Nacional de Ciencia y Tecnología en México, entre 2002 y 2014. Los proyectos fueron sistematizados y clasificados de acuerdo con el tipo de investigación, disciplina o temática, y objetivo de generación de conocimiento. Con estos datos, se elaboró un modelo econométrico que relacional el financiamiento con las características de los proyectos. Los resultados muestran que el financiamiento está centrado en áreas básica y biomédica, particularmente en investigación genética, y que los recursos destinados a la investigación en diabetes se han incrementado en el tiempo pero no de manera constante, sino coyuntural. En los proyectos de investigación sobre diabetes hay un alto nivel de concentración en varias dimensiones: áreas de investigación, temáticas, objeto de estudio, instituciones que realizan la investigación, y regiones. El análisis de la asignación de recursos sugiere que México necesita una agenda de investigación en diabetes más fuerte y orientada, con fundamento en discusiones sobre el equilibrio entre investigación básica y aplicada, y sobre investigación orientada hacia implementaciones de tipo práctico. SE discute también la importancia de promover investigación sobre el sistema de salud para mejorar el cuidado a los pacientes con diabetes, así como la de implementar mecanismos para evaluar el impacto de la investigación en diabetes a corto, mediano y largo plazo, como parte de la política de ciencia y tecnología en México.

Resumo: No México, o diabetes representa um grave problema de saúde pública e uma doença de custo elevado para o sistema de saúde. A pesquisa em saúde é essencial para gerar novos conhecimentos para combater o problema, mas não há informação suficiente para gerar e utilizá-los. O artigo examina o financiamento público de 303 projetos de pesquisa em diabetes, através do Conselho Nacional de Ciência e Tecnologia do México entre 2002 e 2014. Os projetos foram sistematizados e classificados de acordo com o tipo de pesquisa, disciplina ou assunto e o objetivo do conhecimento. Com base nessa informação, foi preparado um modelo econométrico que associa o financiamento às características dos projetos. Os resultados mostram que o financiamento está concentrado nas áreas de pesquisa básica e biomédica, principalmente em pesquisa genética, e que os recursos para pesquisa em diabetes aumentaram ao longo do tempo, não continuamente, mas ciclicamente. Os projetos de pesquisa em diabetes mostram uma forte concentração em diversas dimensões: área de pesquisa, tema, objeto, instituição que realiza a pesquisa e região do país. A análise da alocação de recursos sugere que o México precisa de uma agenda de pesquisa mais forte e orientada, com bases que incluam discussões sobre o equilíbrio entre pesquisa básica e aplicada, e para pesquisa voltada para implementações práticas. O artigo também discute a importância de promover pesquisas em sistemas de saúde para melhorar os cuidados em diabetes, além de implementar mecanismos para avaliar o impacto da pesquisa em diabetes no curto, médio e longo prazo como parte da política de ciência e tecnologia do país.

Scavenging of photogenerated ROS by Oxicams. Possible biological and environmental implications.

The profusely employed drugs Piroxicam (Piro), Tenoxicam (Teno) and Meloxicam (Melo) belonging to the non-steroidal antiinflammatory drug (NSAID) family of the Oxicams (Oxis) were studied in the frame of two specific conditions: (a) their ROS scavenging ability, in relation to a possible biological antioxidant action and (b) their photodegradability under environmental conditions, in the context of Oxi-contaminated waters. Singlet molecular oxygen (O2((1)Δg)) and superoxide radical anion (O2(-)) were photogenerated through Riboflavin (Rf, vitamin B2)-photosensitization in aqueous and aqueous-methanolic solutions in the presence of Oxi concentrations in the range 50-500 µM. The visible-light absorber vitamin is currently present in all types of natural waters and constitutes the most frequent endogenous photosensitizer in mammals. Hence, it was employed in order to mimic both natural sceneries of interest. All three Oxis quench O2((1)Δg) with rate constants in the order of 10(8)M(-1)s(-1) showing a significant photodegradation efficiency given by a dominant reactive fashion for deactivation of the oxidative species. Although this is not a desirable property in the context of photoprotection upon prolonged photoirradiation, constitutes in fact a promissory aspect for the degradation NSAIDs, in waste waters. Indirect evidence indicates that Melo is also oxidized through a O2(-)-mediated component. The simultaneous presence of Piro plus tryptophan or tyrosine under Rf-photosensitizing conditions, which has taken the amino acids as photooxidizable model residues in a proteinaceous environment, indicates that the NSAID induces a protection of the biomolecules against photodynamic degradation.

On the photooxidation of the multifunctional drug niclosamide. A kinetic study in the presence of vitamin B2 and visible light.

OBJECTIVES: The multifunctional drug niclosamide (NSD), extensively employed therapeutically, is a frequent pollutant of surface waters. Considering the environmental importance of photodegradative processes for this type of contaminant, the kinetic and mechanistic aspects of the possible visible-light-mediated photooxidation of NSD were studied under naturalistic conditions. METHODS: The visible-light absorber riboflavin (vitamin B2) was employed as a photosensitizer. The vitamin can usually be found in natural waters and is the most common endogenous photosensitizer in mammals. The interaction of NSD with electronically excited states of Rf and with photogenerated reactive oxygen species (ROS) was evaluated through conventional UV spectroscopy, laser flash photolysis, time-resolved phosphorescence detection of singlet molecular oxygen (O2((1)Δg)), and polarographic dosage of dissolved oxygen. RESULTS: Ground state NSD quenched the long-lived triplet excited state of Rf ((3)Rf*) and the photogenerated ROS (O2((1)Δg)) and superoxide radical anion (O2•−). As a result, NSD was photooxidized. The rate constants for the interaction NSD-O2((1)Δg) are particularly low, in the order of 10(6)/M/s, although the whole interaction is attributable to a pure reactive process. The O2((1)Δg) quenching was faster in alkaline medium, favored by the ionization of the NSD phenolic group. Under Rf-photosensitization, NSD was degraded very much more rapidly than phenol, the latter being considered a paradigmatic water-contaminant model compound. NSD may behave as an antioxidant in bio-environments, as demonstrated employing the photooxidizable amino acid tryptophan as a relevant biological target. DISCUSSION: The results indicate that a O2•−-mediated process is the main route for the Rf-sensitized photooxidation of NSD. Photodegradation of the biocide in the presence and absence of phenol and tryptophan was quantitatively evaluated, discussed, and interpreted in terms of competitive quenching processes of (3)Rf*, O2((1)Δg), and O2•− by the substrates.

The employment of a removable chitosan-derivatized polymeric sensitizer in the photooxidation of polyhydroxylated water-pollutants.

The known O2((1)∆g)-sensitizer system Chitosan bounded Rose Bengal (CH-RB), with Rose Bengal (RB) immobilized by irreversible covalent bonding to the polymer Chitosan (CH), soluble in aquous acidic medium, was employed in the photodegradation of three tri-hydroxy benzene water-contaminants (THBs). The system sensitizes the O2((1)∆g)-mediated photodegradation of THBs by a process kinetically favored, as compared to that employing free RB dissolved in the same solvent. Additionally the free xanthene dye, degradable by O2((1)∆g) through self-sensitization upon prolonged light-exposure, is considerably protected when bonded to CH-polymer. The polymeric sensitizer, totally insoluble in neutral medium, can be removed from the solution after the photodegradative cycle by precipitation through a simple pH change. This fact constitutes an interesting aspect in the context of photoremediation of confined polluted waters. In other words, the sensitizing system could be useful for avoiding to dissolve dyestuffs in the polluted waters, in order to act as conventional sunlight-absorbing dye-sensitizers. In parallel the interaction CH-O2((1)∆g) in acidic solution was evaluated. The polymer quenches the oxidative species with a rate constant 2.4 × 10(8) M(-1) s(-1) being the process mostly attributable to a physical interaction. This fact promotes the photoprotection of the bonded dye in the CH-RB polymer.

On the natural fate of maleic hydrazide. Kinetic aspects of the photochemical and microbiological degradation of the herbicide.

Kinetic and mechanistic aspects of the photochemical and microbiological degradation of the herbicide Maleic Hydrazide (MH) have been studied. Riboflavin (Rf, vitamin B2) was employed as a main photosensitizer whereas Humic Acid (HA) was included as a second sensitizer in order to more closely simulate natural environmental conditions. MH quenches excited singlet and triplet states of Rf, with rate constants close to the diffusion limit. The herbicide and dissolved molecular oxygen competitively quench triplet excited Rf. As a consequence the reactive oxygen species (ROS), superoxide radical anion (O2(-·)), hydrogen peroxide (H2O2) and singlet molecular oxygen (O2((1)Δg)) are produced by electron- and energy-transfer processes, respectively, as demonstrated by auxiliary experiments employing selective auxiliary quenchers and the exclusive O2((1)Δg) generator Rose Bengal (RB). As a global result, the photodegradation of Rf is retarded, whereas MH is degraded by the generated ROS. The bacteria Pseudomonas aeruginosa (Ps) and Bacillus subtilis (Bs), recognized as contaminants surface-water and soil and microbial antagonists of phytopathogenic, were used in the microbiological experiments. Results of the individual incubation of both bacteria in in the presence of MH indicate a stimulation on the Ps growth, implying the biodegradation of the herbicide, whereas MH only exerted a bacteriostatic effect on Bs.

The role of vitamin B6 as an antioxidant in the presence of vitamin B2-photogenerated reactive oxygen species. A kinetic and mechanistic study.

We report on the photostability of a mixture of vitamins B6 and B2 (riboflavin, Rf) upon visible light irradiation and on the possible role of the vitamin B6 family (B6D) as deactivators of reactive oxygen species (ROS). The work is a systematic kinetic and mechanistic study under conditions in which only Rf absorbs photoirradiation. Pyridoxine, pyridoxal hydrochloride, pyridoxal phosphate and pyridoxamine dihydrochloride were studied as representative members of the vitamin B6 family. The visible light irradiation of dissolved Rf and B6D in pH 7.4 aqueous medium under aerobic conditions induces photoprocesses that mainly produce B6D degradation. The overall oxidative mechanism involves the participation of ROS. Photogenerated (3)Rf* is quenched either by oxygen, giving rise to O(2)((1)Δ(g)) by electronic energy transfer to dissolved ground state oxygen, or by B6D yielding, through an electron transfer process, the neutral radical RfH˙, and O(2)˙(-) in an subsequent step. B6D act as quenchers of O(2)((1)Δ(g)) and O(2)˙(-), the former in a totally reactive event that also inhibits Rf photoconsumption. The common chromophoric moiety of B6D represented by 3-hydroxypyridine, constitutes an excellent model that mimics the kinetic behavior of the vitamin as an antioxidant towards Rf-generated ROS. The protein lysozyme, taken as an O(2)((1)Δ(g))-mediated oxidizable biological target, is photoprotected by B6D from Rf-sensitized photodegradation through the quenching of electronically excited triplet state of the pigment, in a process that competes with O(2)((1)Δ(g)) generation.

Vitamin B1 as a scavenger of reactive oxygen species photogenerated by vitamin B2.

Kinetics and mechanism of photoprocesses generated by visible light-irradiation of the system riboflavin (Rf, vitamin B2) plus Thiamine (Th) and Thiamine pyrophosphate (ThDP), representing vitamin B1, was studied in pH 7 water. A weak dark complex vitamin B2-vitamin B1, with a mean value of 4 ± 0.4 M(-1) is formed. An intricate mechanism of competitive reactions operates upon photoirradiation, being the light only absorbed by Rf. Th and ThDP quench excited singlet and triplet states of Rf, with rate constants in the order of 10(9) and 10(6 ) M(-1 ) s(-1), respectively. With Vitamin B1 in a concentration similar to that of dissolved molecular oxygen in water, the quenching of triplet excited Rf by the latter is highly predominant, resulting in the generation of O(2)((1)Δ(g)). Superoxide radical anion was not detected under work conditions. A relatively slow O(2)((1)Δ(g))-mediated photodegradation of Th and ThDP was observed. Nevertheless, Th and especially ThDP behave as efficient physical deactivators of O(2)((1)Δ(g)). The thiazol structure in vitamin B1 appears as a good scavenger of this reactive oxygen species. This characteristic, that presents at vitamin B1 as a potential photoprotector of biological entities against O(2)((1)Δ(g)) attack, was been experimentally confirmed employing the protein lisozime as a photo-oxidizable target.

Spirobifluorene-bridged donor/acceptor dye for organic dye-sensitized solar cells.

A new dye, SSD1, featuring two donor/acceptor chromophores aligned in a spiro configuration with two anchoring groups separated at a distance of 10.05 A (closely matching the distance between the adsorption sites of the anatase TiO(2) surface) undergoes efficient dye adherence on TiO(2) films. A dye-sensitized solar cell incorporating SSD1 exhibited a short-circuit current of 8.9 mA cm(-2), an open-circuit voltage of 0.63 V, a fill factor of 0.67, and a power conversion efficiency of 3.75%.