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1.
Rev. neurol. (Ed. impr.) ; 78(7): 185-197, Ene-Jun, 2024. tab, ilus
Artigo em Espanhol | IBECS | ID: ibc-232184

RESUMO

Introducción: Los objetivos primarios del core data set son reducir la heterogeneidad y promover la armonización entre las fuentes de datos en la esclerosis múltiple (EM), reduciendo así el tiempo necesario para ejecutar esfuerzos en la recolección de datos de vida real. Recientemente, un grupo liderado por la Multiple Sclerosis Data Alliance ha desarrollado un core data set para la recolección de datos del mundo real en EM a nivel global. Nuestro objetivo ha sido adaptar y consensuar este conjunto de datos globales a las necesidades de América Latina para que pueda ser implementado por los registros ya desarrollados y en proceso de desarrollo en la región. Material y métodos. Se conformó un grupo de trabajo regionalmente y se adaptó el core data set creado globalmente (proceso de traducción al español, incorporación de variables regionales y consenso sobre variables que se iban a utilizar). El consenso se obtuvo a través de la metodología Delphi remoto de ronda de cuestionarios y discusión a distancia de las variables del core data set. Resultados: Veinticinco profesionales de América Latina llevaron adelante el proceso de adaptación entre noviembre de 2022 y julio de 2023. Se estableció un acuerdo sobre un core data set de nueve categorías y 45 variables, versión 2023, con la sugerencia de implementarlo en registros desarrollados o en vías de desarrollo y cohortes de EM en la región. Conclusión: El core data set busca armonizar las variables recolectadas por los registros y las cohortes de EM en América Latina con el fin de facilitar dicha recolección y permitir una colaboración entre fuentes. Su implementación facilitará la recolección de datos de vida real y la colaboración en la región.(AU)


Introduction: The primary objective of the core data set is to reduce heterogeneity and promote harmonization among data sources in EM, thereby reducing the time needed to execute real life data collection efforts. Recently, a group led by the Multiple Sclerosis Data Alliance has developed a core data set for collecting real-world data on multiple sclerosis (MS) globally. Our objective was to adapt this global data set to the needs of Latin America, so that it can be implemented by the registries already developed and in the process of development in the region. Material and methods: A working group was formed regionally, the core data set created globally was adapted (translation process into Spanish, incorporation of regional variables and consensus on variables to be used). Consensus was obtained through the remote Delphi methodology of a round of questionnaires and remote discussion of the core data set variables. Results: A total of 25 professionals from Latin America carried out the adaptation process between November 2022 and July 2023. Agreement was established on a core data set of nine categories and 45 variables, version 2023 to suggest its implementation in developed or developing registries, and MS cohorts in the region. Conclusion: The core data set seeks to harmonize the variables collected by registries and cohorts in MS in Latin America in order to facilitate said collection and allow collaboration between sources. Its implementation will facilitate real life data collection and collaboration in the region.(AU)


Assuntos
Humanos , Masculino , Feminino , Esclerose Múltipla/epidemiologia , Ficha Clínica , Registros Médicos , América Latina/epidemiologia , Neurologia , Doenças do Sistema Nervoso
2.
Rev Neurol ; 78(7): 185-197, 2024 Apr 01.
Artigo em Espanhol | MEDLINE | ID: mdl-38502167

RESUMO

INTRODUCTION: The primary objective of the core data set is to reduce heterogeneity and promote harmonization among data sources in EM, thereby reducing the time needed to execute real life data collection efforts. Recently, a group led by the Multiple Sclerosis Data Alliance has developed a core data set for collecting real-world data on multiple sclerosis (MS) globally. Our objective was to adapt this global data set to the needs of Latin America, so that it can be implemented by the registries already developed and in the process of development in the region. MATERIAL AND METHODS: A working group was formed regionally, the core data set created globally was adapted (translation process into Spanish, incorporation of regional variables and consensus on variables to be used). Consensus was obtained through the remote Delphi methodology of a round of questionnaires and remote discussion of the core data set variables. RESULTS: A total of 25 professionals from Latin America carried out the adaptation process between November 2022 and July 2023. Agreement was established on a core data set of nine categories and 45 variables, version 2023 to suggest its implementation in developed or developing registries, and MS cohorts in the region. CONCLUSION: The core data set seeks to harmonize the variables collected by registries and cohorts in MS in Latin America in order to facilitate said collection and allow collaboration between sources. Its implementation will facilitate real life data collection and collaboration in the region.


TITLE: Core data set para la generación de datos de la vida real en esclerosis múltiple: adaptación de una iniciativa global para América Latina.Introducción. Los objetivos primarios del core data set son reducir la heterogeneidad y promover la armonización entre las fuentes de datos en la esclerosis múltiple (EM), reduciendo así el tiempo necesario para ejecutar esfuerzos en la recolección de datos de vida real. Recientemente, un grupo liderado por la Multiple Sclerosis Data Alliance ha desarrollado un core data set para la recolección de datos del mundo real en EM a nivel global. Nuestro objetivo ha sido adaptar y consensuar este conjunto de datos globales a las necesidades de América Latina para que pueda ser implementado por los registros ya desarrollados y en proceso de desarrollo en la región. Material y métodos. Se conformó un grupo de trabajo regionalmente y se adaptó el core data set creado globalmente (proceso de traducción al español, incorporación de variables regionales y consenso sobre variables que se iban a utilizar). El consenso se obtuvo a través de la metodología Delphi remoto de ronda de cuestionarios y discusión a distancia de las variables del core data set. Resultados. Veinticinco profesionales de América Latina llevaron adelante el proceso de adaptación entre noviembre de 2022 y julio de 2023. Se estableció un acuerdo sobre un core data set de nueve categorías y 45 variables, versión 2023, con la sugerencia de implementarlo en registros desarrollados o en vías de desarrollo y cohortes de EM en la región. Conclusión. El core data set busca armonizar las variables recolectadas por los registros y las cohortes de EM en América Latina con el fin de facilitar dicha recolección y permitir una colaboración entre fuentes. Su implementación facilitará la recolección de datos de vida real y la colaboración en la región.


Assuntos
Esclerose Múltipla , Humanos , América Latina/epidemiologia , Esclerose Múltipla/epidemiologia , Comitês Consultivos , Consenso , Sistema de Registros
3.
Chemosphere ; 345: 140418, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37844702

RESUMO

Carbon-integrated binary metal oxide semiconductors have gained prominence in the last decade as a better material for photocatalytic wastewater treatment technology. In this regard, this research describes the investigation of the binary metal oxide TiO2@Fe3O4 embedded on reduced graphene oxide (rGO) nanosheets synthesized through a combination of sol-gel, chemical precipitation, and Hummer's processes. Besides, the catalyst is applied for the photocatalytic degradation of organic chlorophenol pollutants. The characterized diffraction results showed the peak broadening of the rGO-TiO2@Fe3O4 composite formed with tetragonal and cubic structures having small crystallite sizes. The TEM observation shows an enormous miniature of TiO2@Fe3O4 nanospheres spread on the folded 2D-rGO nanosheets with a large BET surface area. The XPS result holds the mixed phases of Fe3O4 and Fe2O3. Finally, the catalyst demonstrated a low band gap with extended light absorption towards visible light irradiation. The synergistic interactions between Fe3+ and Fe2+ improved the visible light activity due to the incorporation of rGO, and also possessed good recycling capacity. The increased mobility of electrons at the interfaces of TiO2 and Fe3O4 due to the mixing of rGO results in the separation of charge carriers by elevating the photocatalytic degradation efficiency of chlorophenol.


Assuntos
Clorofenóis , Grafite , Águas Residuárias , Grafite/química , Luz , Óxidos/química , Clorofenóis/química , Catálise
4.
Environ Res ; 236(Pt 2): 116790, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37517483

RESUMO

The present study highlights the treatment of industrial effluent, which is one of the most life-threatening factors. Herein, for the first time, two types of NiO (green and black) photocatalysts were prepared by facile chemical precipitation and thermal decomposition methods separately. The synthesized NiO materials were demonstrated with various instrumental techniques for finding their characteristics. The X-ray diffraction studies (XRD) and X-ray photoelectron spectroscopy (XPS) revealed the presence of Ni2O3 in black NiO material. The transmission electron microscopic (TEM) images engrained the nanospherical shaped green NiO and nanoflower shaped black NiO/Ni2O3 materials. Further, the band gap of black NiO nanoflower was 2.9 eV compared to green NiO having 3.8 eV obtained from UV-vis spectroscopy. Meanwhile, both NiO catalysts were employed for visible light degradation, which yields a 60.3% efficiency of black NiO comparable to a 4.3% efficiency of green NiO within 180 min of exposure. The higher degrading efficiency of black NiO was due to the presence of Ni2O3 and the development of pores, which was evident from the Barrett-Joyner-Halenda (BJH) method. Type IV hysteresis was observed in black NiO nanoflowers with high surface area and pore size measurements. This black NiO/Ni2O3 synthesized from the thermal decomposition method has promoted better photocatalytic degradation of 4-chlorophenol upon exposure to visible light and is applicable for other industrial pollutants.


Assuntos
Clorofenóis , Luz , Clorofenóis/química , Análise Espectral , Catálise
5.
Environ Res ; 222: 115358, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36702188

RESUMO

The subject of water contamination and how it gets defiled to the society and humans is confabulating from the past decades. Phenolic compounds widely exist in the water sources and it is emergent to determine the toxicity in natural and drinking water, because it is hazardous to the humans. Among these compounds, catechol has sought a strong concern because of its rapid occurrence in nature and its potential toxicity to humans. The present work aims to develop an effective electrochemical sensing of catechol using mesoporous structure of Fe3O4-TiO2 decorated on glassy carbon (GC) electrode. The creation of pure TiO2 using the sol-gel technique was the first step in the synthesis protocol for binary nanocomposite, which was then followed by the loading of Fe3O4 nanoparticles on the surface of TiO2 using the thermal decomposition method. The resultant Fe3O4-TiO2 based nanocomposite exhibited mesoporous structure and the cavities were occupied with highly active magnetite nanoparticles (Fe3O4) with high specific surface area (90.63 m2/g). When compared to pure TiO2, catechol showed a more prominent electrochemical response for Fe3O4-TiO2, with a significant increase in anodic peak current at a lower oxidation potential (0.387 V) with a detection limit of 45 µM. Therefore, the prepared magnetite binary nanocomposite can serve as an efficient electroactive material for sensing of catechol, which could also act as a promising electrocatalyst for various electrocatalytic applications.


Assuntos
Carbono , Nanopartículas de Magnetita , Humanos , Carbono/química , Nanopartículas de Magnetita/química , Catecóis , Água
6.
Environ Res ; 216(Pt 1): 114428, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36179883

RESUMO

Creating mesoporous architecture on the surface of metal oxides without using pore creating agent is significant interest in electrochemical sensors because these materials act as an efficient electron transfer process between the electrode interface and the analytes. Recent advances in mesoporous titanium dioxide (TiO2)-based materials have acquired extraordinary opportunities because of their interconnected porous structure could act as a host for doping with various transition metals or heteroatoms to form a new type of heterojunction. Herein, a simple method is developed to synthesize mesoporous copper oxide (CuO) decorated on TiO2 nanostructures in which homogenous shaped CuO nanocrystals act as dopants decorated on the mesoporous structure of TiO2, resulting in p-n heterojunction nanocomposite. The TiO2 particles exhibit a mesoporous structure with a pore volume of about 0.117 cm3/g is capable to load CuO nanocrystals on the surface. As a result, large pore volume 0.304 cm³/g is obtained for CuO-TiO2 heterojunction nanocomposite with the loading of uniform-shaped CuO nanocrystals on the mesoporous TiO2. The resulting CuO-TiO2 nanocomposite on modified glassy carbon (GC) electrode exhibits good electrochemical performance for oxidation of catechol with the observation of strong enhancement in the anodic peak potential at +0.36 V. The decrease in the overpotential for the oxidation of catechol when compared to TiO2/GC is attributed to the presence of CuO nanocrystals providing a large surface area, resulting in wide linear range 10 nM to 0.57 µM. Moreover, the resultant modified electrode exhibited good sensitivity, selectivity and reproducibility and the sensor could able to determine the presence of catechol in real samples such as lake and river water. Therefore, the obtained CuO-TiO2 nanocomposite on the modified GC delivered good electrochemical sensing performance and which could be able to perform a promising strategy for designing various metal oxide doped nanocomposites for various photochemical and electrocatalytic applications.


Assuntos
Técnicas Eletroquímicas , Nanocompostos , Técnicas Eletroquímicas/métodos , Reprodutibilidade dos Testes , Cobre/química , Nanocompostos/química , Óxidos/química , Carbono/química , Catecóis , Água
7.
Environ Res ; 215(Pt 3): 114427, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36179884

RESUMO

The capacity to generate a constant signal response from an enzyme on an electrode surface has been a fascinating topic of research from the past three decades. To nourish the enzymatic activity during electrochemical reactions, the immobilization of dual enzymes on the electrode surface could prevent the enzymatic loss without denaturation and thus long-term stability can be achieved. For effective immobilization of dual enzymes, mesoporous materials are the ideal choice because of its numerous advantages such as 1. The presence of porous structure facilitates high loading of enzymes 2. The formation of protective environment can withstand the enzymatic activity even at acidic or basic pH values and even at elevated temperatures. Herein, we develop bienzymatic immobilization of horseradish peroxidase (HRP) and cholesterol oxidase (ChOx) on mesoporous V2O5-TiO2 based binary nanocomposite for effective sensing of hydrogen peroxide (H2O2) in presence of redox mediator hydroquinone (HQ). The utilization of redox mediator in second-generation biosensing of H2O2 can eliminate the interference species and reduces the operating potential with higher current density for electrochemical reduction reaction. Using this mediator transfer process approach at HRP/ChOx/V2O5-TiO2 modified GC, the H2O2 can be determined at operating potential (-0.2 V) with good linear range (0.05-3.5 mM) higher sensitivity (1040 µAµM-1 cm-2) and lower detection limit of about 20 µM can be attained, which is due to higher mediation of electrons were transferred to the enzyme cofactors. These interesting characteristics could be due to mesoporous structure of V2O5-TiO2 can induce large immobilization and facilitate higher interaction with enzymes for wide range of biosensing applications.


Assuntos
Técnicas Biossensoriais , Peróxido de Hidrogênio , Colesterol Oxidase , Coenzimas , Enzimas Imobilizadas/química , Peroxidase do Rábano Silvestre/química , Peróxido de Hidrogênio/química , Hidroquinonas , Titânio
8.
Sci Total Environ ; 846: 157410, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-35850332

RESUMO

During the last decades many salt marshes worldwide have suffered important losses in their extent and associated ecosystem services. The salt marshes of San Vicente de la Barquera estuary (N Spain) are a clear example of this, with a drastic reduction in vegetation surface over the last 60 years. This paper provides insights into the main factors controlling salt marsh functioning in sheltered estuarine areas. Regional and local factors have been disaggregated to identify the main drivers controlling the functioning of the salt marsh to develop appropriate management measures according to the evolution of the system. These factors have been studied in their spatial context through detailed maps of change in vegetation cover combined with topographic data obtained from UAV and RTK-DGPS surveys. The results demonstrate that in this estuary the salt marsh area is declining following a fragmentation process. No clear pattern of vegetation loss/gain with elevation has been identified. However, the results point to increased hydrodynamic stress in the area, with stronger currents inside the estuary. This is probably the major factor responsible for the decline of the salt marshes in the San Vicente de la Barquera estuary. Furthermore, several human interventions during the 20th century (local drivers) have also probably contributed to a lower resilience against SLR (regional driver). This work demonstrates that both natural and human drivers of change need to be considered when characterizing the evolution of salt marshes, wherever efficient management strategies need to be designed.


Assuntos
Estuários , Áreas Alagadas , Ecossistema , Espanha
9.
Food Chem Toxicol ; 165: 113182, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35643232

RESUMO

Enhancing the current signal response for semiconductors is the key factor for designing and fabrication of efficient electrode in electrochemical sensors. By the aid of doping with binary metal oxides, the conductivity of the resultant titanium oxide (TiO2) based nanocomposite will deliver fast electron transfer rate at the heterojunction interface. Herein, by taking advantage of mesoporous structure in TiO2, cubic shaped multivalent cerium oxide (CeO2) was incorporated into the porous cavity by simple ground assisted solvothermal process, which resulted in enormous enhancement in the current response towards detection of 2-aminophenol. The advantage of CeO2 on TiO2 not only involves the loading of binary metal oxide on its mesoporous sites, but also facilitates the formation of CeO2 nanocrystals which induce larger surface area and high electroactive sites with rapid diffusion of target species through pores. As a result, CeO2-TiO2 on modified GC electrode exhibits drastic enhancement in the current response for oxidation of 2-aminophenol with large decrease in the onset potential than TiO2/GC electrode. Furthermore, the CeO2-TiO2 modified electrode shows significant behavior for sensing of 2-aminophenol with wide linear range of 0.01-500 µM. The sensitivity and detection limit were calculated to be 0.603 µA µM cm-2 and 3.5 nM respectively. This work establishes the facile strategy for decoration of binary metal oxide-based nanocomposites as effective electrode and also possible to create new opportunities in the designing and fabrication of variety of efficient electrode in various electrochemical applications.


Assuntos
Nanopartículas Metálicas , Titânio , Aminofenóis , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Óxidos/química , Titânio/química
10.
J Hazard Mater ; 424(Pt B): 127464, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34653855

RESUMO

In recent times, visible light enhancement has become much more considered due to the enlightening properties of nanocomposite systems. This has potential applications for wastewater treatment due to the blemish of toxic organic chemicals from industrial sectors. Therefore, this work is focused on novel 3D ZnO/SnO2 nanocomposites synthesized by the green method (orange peel extracts supported combined chemical processes) utilized for the removal of chlorophenol effluent. The orange peel extract has been incorporated as one of the major components to synthesize an effective nanocomposite. Also, the pure materials were synthesized along with these nanocomposites and tested under various instrumental techniques. The characterized results showed that the composites prepared with orange peel extract exhibited hexagonal 3D ZnO nanospheres with 3D tetragonal structured SnO2 nanocubes. Elemental analysis showed that the partial amount of SnO2 has transformed to SnO due to the reducing ability of orange peel extract. Also, the existing different (Zn2+, Sn4+, and Sn2+) states helped in delaying the transfer of electron-hole recombination to obtain photocatalytic chlorophenol degradation. Further, the prevailing line dislocation can compromise more vacancy and interact with more electrons. The high surface area, least crystallite size, and lower bandgap inspired to enhance the visible light activity. Simultaneously, the pure form of nanomaterial has poor light absorption under visible light. This study achieves the photocatalytic degradation of 77.5% against chlorophenol using a green 3D composite system.


Assuntos
Clorofenóis , Citrus sinensis , Nanocompostos , Óxido de Zinco , Catálise , Extratos Vegetais , Compostos de Estanho
11.
Environ Pollut ; 287: 117304, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34015669

RESUMO

The treatment of industrial waste and harmful bacteria is an important topic due to the release of toxins from the industrial pollutants that damage the water resources. These harmful sources frighten the life of every organism which was later developed as the carcinogenic and mutagenic agents. Therefore, the current study focuses on the breakdown or degradation of 4-chlorophenol and the antibacterial activity against Escherichia coli (E. coli). As a well-known catalyst, pure titanium-di-oxide (TiO2) had not shown the photocatalytic activity in the visible light region. Hence, band position of TiO2 need to be shifted to bring out the absorption in the visible light region. For this purpose, the n-type TiO2 nanocrystalline material's band gap got varied by adding different ratios of p-type CuO. The result had appeared in the formation of p (CuO) - n (TiO2) junction synthesized from sol-gel followed by chemical precipitation methods. The optical band gap value was determined by Kubelka-Munk (K-M) plot through UV-Vis diffusive reflectance spectroscopy (DRS). Further, the comprehensive mechanism and the results of photocatalytic and antibacterial activities were discussed in detail. These investigations are made for tuning the TiO2 catalyst towards improving or eliminating the existing various environmental damages.


Assuntos
Escherichia coli , Titânio , Antibacterianos , Catálise , Clorofenóis , Cobre , Luz , Fotólise
12.
Environ Res ; 197: 111203, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33894234

RESUMO

Changes in the frequency and magnitude of extreme weather events represent one of the key indicators of climate change and variability. These events can have an important impact on mortality rates, especially in the ageing population. This study assessed the spatial and seasonal distributions of mortality rates in mainland Spain and their association with climatic conditions over the period 1979-2016. The analysis was done on a seasonal and annual basis using 79 climatic indices and regional natural deaths data. Results indicate large spatial variability of natural deaths, which is mostly related to how the share of the elderly in the population varied across the studied regions. Spatially, both the highest mortality rates and the largest percentage of elders were found in the northwest areas of the study domain, where an extreme climate prevails, with very cold winters and hot summers. A strong seasonality effect was observed, winter shows more than 10% of natural deaths compared to the rest of the seasons. Also, results suggest a strong relation between climatic indices and natural deaths, albeit with a high spatial and seasonal variability. Climatic indices and natural deaths show a stronger correlation in winter and summer than in spring and autumn.


Assuntos
Mudança Climática , Temperatura Baixa , Idoso , Envelhecimento , Humanos , Mortalidade , Estações do Ano , Espanha/epidemiologia
13.
Environ Res ; 195: 110852, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33556356

RESUMO

In recent times, cost effective synthesis of semiconductor materials has been a subject of concern for the day to today applications. In this work, novelty has been made on the facile synthesis of metal oxides (TiO2 and CeO2) and nanocomposites (TiO2-CeO2) through sol-gel and precipitation methods of imparting lemon extract. The synthesized materials behave as the functional catalysts which has been further carried out for the photocatalytic degradation against 2,4-Dichlorophenol (2,4-DCP). The materials are then valued for the structural and optical properties. The lemon extract used in synthesis has played a premier role in upgrading the charge carrier separation, bandgap, and size reduction of the composite system. Further, the CeO2 supported TiO2 sample acts as the better visible light catalyst, due to the prevention of aggregation and existence of line dislocation that supported to access the additional electron trap sites.


Assuntos
Clorofenóis , Nanocompostos , Titânio
16.
Sci Total Environ ; 726: 138601, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32315859

RESUMO

The aim of the present study consists on the establishment of any relationship or interaction between geomorphological processes and vegetation/habitat distribution in an area with strong environmental gradients: an active saline lake in NE Spain. The resulting maps of the major geoforms and CORINE habitats within the lacustrine area were overlain to determine any significant relationships, taking into account the elevation derived from Lidar data. Whereas the geoforms resulted to have a roughly concentric distribution, the habitats appeared to be spread across different areas, and flooding frequency seemed not to be a determining factor in their altitudinal distribution. The correspondence matrix for geoforms and habitats underlined the coincidence between presently active morphodynamic units, flooding/salinity, and habitats typical of saline environments. Geomorphological units associated with the presently active shoreline dynamics host the habitats more typically related to frequent flooding and high salinity levels. The delay between geomorphological dynamics and vegetation changes, together with the opportunistic character of vegetation, promote the coexistence of different geomorphological processes and a great variety of plant communities and habitats. As a major conclusion, the present study provides a method through which a standard procedure may be set up to further determine the interaction between geomorphological processes and vegetation distribution, very useful for understanding vegetation patterns and conservation biodiversity, and the planning and managing of Natura 2000 sites.

17.
J Colloid Interface Sci ; 542: 45-53, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30721835

RESUMO

The detection of water soluble vitamins using electrochemical method is widely established in pharmaceutical quality control laboratories, and especially the recent advances in hybrid heterostrucure nanomaterials has devoted to enhance the significant analytical parameters like sensitivity, selectivity and fast response time. Herein, we report the synthesis of a hybrid heterostructure comprising SnO2 nanoparticles supported mesoporous TiO2, and the obtained nanocomposite were fabricated over glassy carbon electrode (GCE) for the electrochemical oxidation of vitamin B6 in pharmaceutical tablets. The designed SnO2-TiO2/GC modified electrode exhibits well-defined oxidation peak with lowering over-potential and larger signal response compared to the pristine counterparts, and it is mainly due to the formation of abundant active surface layer offered by SnO2 cocatalyst, and thus significantly enhances the electrochemical surface area. Differential pulse voltammetry (DPV) measurements revealed a sharp increase in the anodic peak current upon addition of increasing concentration of vitamin B6. The analytical performance of the modified electrode displayed a wide linear range (0.1-31.4 µM), high selectivity, and excellent sensitivity (759.73 µA mM-1 cm-2) with low detection limit (35 nM). Thus, the resultant mesoporous hybrid nanocatalyst provides an efficient electrochemical platform for determination of various potential analytes.


Assuntos
Nanocompostos/química , Compostos de Estanho/química , Titânio/química , Vitamina B 6/análise , Catálise , Técnicas Eletroquímicas , Eletrodos , Limite de Detecção , Oxirredução , Porosidade , Sensibilidade e Especificidade , Comprimidos/química
18.
Int J Biol Macromol ; 109: 1239-1245, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29175525

RESUMO

The inhibition of electrons-holes recombination and enhancement of visible light photocatalytic activity were accomplished by the synthesized TiO2/CS nanocomposites system. In this present work, the different weight ratio of TiO2 and chitosan (75:25, 50:50 and 25:75) nanocomposites were synthesized via two-step method. After that, the existing functional groups, size and structure of the nanocomposites system were characterized via FT-IR, TEM and XRD measurements. The band gap of the prepared materials and its excitation and emission spectra were elevated through UV-vis and PL analyses. Moreover, the MO and MB degradation capability of the synthesized TiO2/CS nanocomposites was optimized, and the outcomes are described in detail.


Assuntos
Quitosana/química , Luz , Nanocompostos/química , Processos Fotoquímicos , Titânio/química , Catálise , Nanopartículas Metálicas/química , Nanocompostos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
19.
J Photochem Photobiol B ; 173: 43-49, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28558305

RESUMO

The progress of the enriched photocatalytic degradation predominantly depends on materials fabrication. In the recent times, the outcomes of nanomaterials show extraordinary efficiency due to its shape and size. In this connection, the present work concentrates on the fabrication of single digit metal oxides (CeO2, CuO, NiO, Mn3O4, SnO2 and ZnO) through precipitation method. The structural information of different metal oxides (MOs) and their crystallite size were estimated via XRD analysis and their consistent results revealed that the crystalline sizes of the prepared metal oxide were exhibited in nano size. The morphology and dimension of the synthesized MOs were identified through FE-SEM and TEM techniques. The FE-SEM images were apparently defined that the actual morphology of each metal oxide expresses different dimension due to nucleation and growth process. The result of UV-vis absorption spectra was helped to identify the band gap of MOs and a suitable light for photocatalytic irradiation. Additionally, the synthesized single digit MOs nanoparticles were magnificently applied for the degradation of methyl orange and methylene blue under UV light irradiation.


Assuntos
Compostos Azo/química , Nanopartículas Metálicas/química , Metais/química , Azul de Metileno/química , Óxidos/química , Catálise , Cério/química , Cobre/química , Compostos de Manganês/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Níquel/química , Fotólise/efeitos da radiação , Espectrofotometria Ultravioleta , Compostos de Estanho/química , Raios Ultravioleta , Difração de Raios X , Óxido de Zinco/química
20.
Sci Rep ; 6: 31641, 2016 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-27528264

RESUMO

In this study, pure ZnO, CeO2 and ZnO/CeO2 nanocomposites were synthesized using a thermal decomposition method and subsequently characterized using different standard techniques. High-resolution X-ray photoelectron spectroscopy measurements confirmed the oxidation states and presence of Zn(2+), Ce(4+), Ce(3+) and different bonded oxygen species in the nanocomposites. The prepared pure ZnO and CeO2 as well as the ZnO/CeO2 nanocomposites with various proportions of ZnO and CeO2 were tested for photocatalytic degradation of methyl orange, methylene blue and phenol under visible-light irradiation. The optimized and highly efficient ZnO/CeO2 (90:10) nanocomposite exhibited enhanced photocatalytic degradation performance for the degradation of methyl orange, methylene blue, and phenol as well as industrial textile effluent compared to ZnO, CeO2 and the other investigated nanocomposites. Moreover, the recycling results demonstrate that the ZnO/CeO2 (90:10) nanocomposite exhibited good stability and long-term durability. Furthermore, the prepared ZnO/CeO2 nanocomposites were used for the electrochemical detection of uric acid and ascorbic acid. The ZnO/CeO2 (90:10) nanocomposite also demonstrated the best detection, sensitivity and performance among the investigated materials in this application. These findings suggest that the synthesized ZnO/CeO2 (90:10) nanocomposite could be effectively used in various applications.

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