Application of EPR Spectroscopy in TiO2 and Nb2O5 Photocatalysis

The interaction of light with semiconducting materials becomes the center of a wide range of technologies, such as photocatalysis. This technology has recently attracted increasing attention due to its prospective uses in green energy and environmental remediation. The characterization of the electronic structure of the semiconductors is essential to a deep understanding of the photocatalytic process since they influence and govern the photocatalytic activity by the formation of reactive radical species. Electron paramagnetic resonance (EPR) spectroscopy is a unique analytical tool that can be employed to monitor the photoinduced phenomena occurring in the solid and liquid phases and provides precise insights into the dynamic and reactivity of the photocatalyst under different experimental conditions. This review focus on the application of EPR in the observation of paramagnetic centers formed upon irradiation of titanium dioxide and niobium oxide photocatalysts. TiO2 and Nb2O5 are very well-known semiconductors that have been widely used for photocatalytic applications. A large number of experimental results on both materials offer a reliable platform to illustrate the contribution of the EPR studies on heterogeneous photocatalysis, particularly in monitoring the photogenerated charge carriers, trap states, and surface charge transfer steps. A detailed overview of EPR-spin trapping techniques in mechanistic studies to follow the nature of the photogenerated species in suspension during the photocatalytic process is presented. The role of the electron donors or the electron acceptors and their effect on the photocatalytic process in the solid or the liquid phase are highlighted.

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Ultra-broadband EPR spectroscopy in field and frequency domains

Physical Chemistry Chemical Physics ◽

10.1039/c7cp07443c ◽

2018 ◽

Vol 20 (22) ◽

pp. 15528-15534 ◽

Cited By ~ 22

Author(s):

P. Neugebauer ◽

D. Bloos ◽

R. Marx ◽

P. Lutz ◽

M. Kern ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Magnetic Properties ◽

Epr Spectroscopy ◽

Paramagnetic Resonance ◽

Powerful Technique ◽

Electronic And Magnetic Properties ◽

Wide Range ◽

Frequency Domains ◽

Electron Paramagnetic

Electron paramagnetic resonance (EPR) is a powerful technique to investigate the electronic and magnetic properties of a wide range of materials.

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The Impact of Nanotechnology on Environment

Materials Science and Engineering ◽

10.4018/978-1-5225-1798-6.ch068 ◽

2017 ◽

pp. 1659-1689

Author(s):

Rathinasabapathi Jayavarthanan ◽

Anima Nanda ◽

M. Amin Bhat

Keyword(s):

Environmental Remediation ◽

Production Equipment ◽

Green Energy ◽

Water Filtration ◽

Innovative Methods ◽

Wide Range ◽

Energy Synthesis ◽

Improved Performance ◽

The Impact ◽

By Products

Nanotechnology is an emerging field that covers a wide range of technologies which are presently under development in nanoscale. It plays a major role in the development of innovative methods to produce new products, to substitute existing production equipment and to reformulate new materials and chemicals with improved performance resulting in less consumption of energy and materials and reduced harm to the environment as well as environmental remediation. The environmental impact of nanotechnology is the possible effects that the use of nanotechnological materials and devices will have on the environment. This impact can be split into two aspects: the potential for nanotechnological innovations to help improve the environment (beneficial part), and the possibly novel type of pollution that nanotechnological materials might cause if released into the environment (harmful part). The nanoparticles can be used an individual product in pure form or as an adjuvant with existing products in order enhance their activities. The beneficial aspects of nanoparticles include water filtration and treatment, green energy synthesis, degradation of plastics, detoxification harmful dyes and chemicals. The harmful aspects consist of unwanted by-products of nanoparticles, effluents of nano industries, etc.

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Approach to TiO2–light interaction in heterogeneous photocatalysis

Water Science & Technology ◽

10.2166/wst.2007.394 ◽

2007 ◽

Vol 55 (12) ◽

pp. 147-151 ◽

Cited By ~ 1

Author(s):

B. Bayarri ◽

E. Illana ◽

D. Curcó ◽

J. Giménez ◽

S. Esplugas

Keyword(s):

Radiation Field ◽

Heterogeneous Photocatalysis ◽

Industrial Processes ◽

Photocatalytic Process ◽

Experimental Conditions ◽

Toxic Pollutants ◽

Light Interaction

Photocatalysis can be a useful tool in the treatment of some recalcitrant and toxic pollutants. In fact, it is being applied today in several industrial processes. However some problems arise in the modelling of photocatalytic systems, most of them related to the radiation field. In this work, some methods are presented which can be powerful tools in the evaluation of the radiation absorbed by the photocatalyst, which is the energy really useful in promoting the photocatalytic process. All these methods are based on actinometric procedures carried out in different experimental conditions and using different photoreactors.

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The Impact of Nanotechnology on Environment

Integrating Biologically-Inspired Nanotechnology into Medical Practice - Advances in Medical Technologies and Clinical Practice ◽

10.4018/978-1-5225-0610-2.ch007 ◽

2017 ◽

pp. 153-193

Author(s):

Rathinasabapathi Jayavarthanan ◽

Anima Nanda ◽

M. Amin Bhat

Keyword(s):

Environmental Remediation ◽

Production Equipment ◽

Green Energy ◽

Water Filtration ◽

Innovative Methods ◽

Wide Range ◽

Energy Synthesis ◽

Improved Performance ◽

The Impact ◽

By Products

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Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

10.26434/chemrxiv.9461462 ◽

2019 ◽

Author(s):

Christopher John ◽

Greg M. Swain ◽

Robert P. Hausinger ◽

Denis A. Proshlyakov

Keyword(s):

Active Site ◽

Structural Model ◽

Heme Iron ◽

Chemical Transformations ◽

Experimental Conditions ◽

Strongly Coupled ◽

Non Heme Iron ◽

Reversible Redox ◽

Wide Range ◽

Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an <i>in situ</i> structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

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Qualitative Analysis of Underlying Factors Affecting Vaccine Hesitancy in Iran- A Study Protocol (Preprint)

10.2196/preprints.22746 ◽

2020 ◽

Author(s):

Salime Goharinezhad

Keyword(s):

Vaccine Coverage ◽

Deep Understanding ◽

World Health ◽

Vaccine Hesitancy ◽

Slight Reduction ◽

Cultural Variation ◽

Global Public Health ◽

Factors Affecting ◽

Wide Range ◽

Context Specific

BACKGROUND World Health Organization declared the vaccine hesitancy as a global public health threat in 2019. Since even a slight reduction in vaccine coverage rates can lead to a decrease in herd immunity, it is imperative to explore the underlying factors affecting vaccine hesitancy. in specific contexts, considering socioeconomic and cultural variation, to ensure interventions targeting hesitancy are well formulated and intervened. OBJECTIVE The main objective of this study is to identify underlying factors affecting vaccine hesitancy in Iran. METHODS A framework qualitative study will be conducted in the west of Tehran province in 2020. Participants in the study will be recruited hesitance-parents who extracted from the SIB system (an electronic health record in Iran) to maximize diversity. Interviews will be analyzed based on ''Determinants of Vaccine Hesitancy Matrix'' which developed by the WHO-SAGE Working Group. RESULTS deep understanding from the context-specific reasons for vaccine hesitancy cause to formulate better strategies to address them. The ultimate goal of this study is to inform future policies to increase the uptake of the vaccine in Iran. CONCLUSIONS This result of study will show variety opinions about vaccination among different types of socioeconomic and demographic households. The wide range of reasons related to vaccine hesitancy imply to more comprehensive, context-specific interventions. Today, the most important intervention issues focus on improving information about effectiveness and safety of vaccines, while other interventions for promoting vaccination is need to addressed.

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Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

International Journal of Molecular Sciences ◽

10.3390/ijms22157879 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7879

Author(s):

Yingxia Gao ◽

Yi Zheng ◽

Léon Sanche

Keyword(s):

Condensed Phase ◽

Genetic Material ◽

High Energy ◽

Dna Lesions ◽

Low Energy ◽

Experimental Investigations ◽

Experimental Conditions ◽

Strand Breaks ◽

Sequence Of Events ◽

Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

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Review of the Upright Balance Assessment Based on the Force Plate

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18052696 ◽

2021 ◽

Vol 18 (5) ◽

pp. 2696

Author(s):

Baoliang Chen ◽

Peng Liu ◽

Feiyun Xiao ◽

Zhengshi Liu ◽

Yong Wang

Keyword(s):

Postural Balance ◽

Force Plate ◽

Assessment Method ◽

Balance Assessment ◽

Experimental Conditions ◽

Methodological Research ◽

Assessment Tests ◽

Wide Range ◽

Foot Posture ◽

Plate System

Quantitative assessment is crucial for the evaluation of human postural balance. The force plate system is the key quantitative balance assessment method. The purpose of this study is to review the important concepts in balance assessment and analyze the experimental conditions, parameter variables, and application scope based on force plate technology. As there is a wide range of balance assessment tests and a variety of commercial force plate systems to choose from, there is room for further improvement of the test details and evaluation variables of the balance assessment. The recommendations presented in this article are the foundation and key part of the postural balance assessment; these recommendations focus on the type of force plate, the subject’s foot posture, and the choice of assessment variables, which further enriches the content of posturography. In order to promote a more reasonable balance assessment method based on force plates, further methodological research and a stronger consensus are still needed.

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Insights into the Antioxidant Mechanism of Newly Synthesized Benzoxazinic Nitrones: In Vitro and In Silico Studies with DPPH Model Radical

Antioxidants ◽

10.3390/antiox10081224 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1224

Author(s):

Stefania Marano ◽

Cristina Minnelli ◽

Lorenzo Ripani ◽

Massimo Marcaccio ◽

Emiliano Laudadio ◽

...

Keyword(s):

Antioxidant Activity ◽

Epr Spectroscopy ◽

Point Of View ◽

Uv Spectrophotometry ◽

Design And Synthesis ◽

Antioxidant Mechanism ◽

Primary Mechanism ◽

In Silico Studies ◽

Wide Range

Synthetic nitrone spin-traps are being explored as therapeutic agents for the treatment of a wide range of oxidative stress-related pathologies, including but not limited to stroke, cancer, cardiovascular, and neurodegenerative diseases. In this context, increasing efforts are currently being made to the design and synthesis of new nitrone-based compounds with enhanced efficacy. The most researched nitrones are surely the ones related to α-phenyl-tert-butylnitrone (PBN) and 5,5-dimethyl-1-pyrroline N-oxide (DMPO) derivatives, which have shown to possess potent biological activity in many experimental animal models. However, more recently, nitrones with a benzoxazinic structure (3-aryl-2H-benzo[1,4]oxazin-N-oxides) have been demonstrated to have superior antioxidant activity compared to PBN. In this study, two new benzoxazinic nitrones bearing an electron-withdrawing methoxycarbonyl group on the benzo moiety (in para and meta positions respect to the nitronyl function) were synthesized. Their in vitro antioxidant activity was evaluated by two cellular-based assays (inhibition of AAPH-induced human erythrocyte hemolysis and cell death in human retinal pigmented epithelium (ARPE-19) cells) and a chemical approach by means of the α,α-diphenyl-β-picrylhydrazyl (DPPH) scavenging assay, using both electron paramagnetic resonance (EPR) spectroscopy and UV spectrophotometry. A computational approach was also used to investigate their potential primary mechanism of antioxidant action, as well as to rationalize the effect of functionalization on the nitrones reactivity toward DPPH, chosen as model radical in this study. Further insights were also gathered by exploring the nitrone electrochemical properties via cyclic voltammetry and by studying their kinetic behavior by means of EPR spectroscopy. Results showed that the introduction of an electron-withdrawing group in the phenyl moiety in the para position significantly increased the antioxidant capacity of benzoxazinic nitrones both in cell and cell-free systems. From the mechanistic point of view, the calculated results closely matched the experimental findings, strongly suggesting that the H-atom transfer (HAT) is likely to be the primary mechanism in the DPPH quenching.

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The Effect of pH, Ionic Strength and the Presence of PbII on the Formation of Calcium Carbonate from Homogenous Alkaline Solutions at Room Temperature

Minerals ◽

10.3390/min11070783 ◽

2021 ◽

Vol 11 (7) ◽

pp. 783

Author(s):

Fulvio Di Lorenzo ◽

Kay Steiner ◽

Sergey V. Churakov

Keyword(s):

Ionic Strength ◽

Deep Understanding ◽

Inhibitory Effect ◽

Alkaline Solutions ◽

Nucleation Kinetics ◽

Experimental Conditions ◽

Calcium Carbonates ◽

Natural Systems ◽

Geological Processes ◽

System Variables

Precipitation of calcium carbonates in aqueous systems is an important factor controlling various industrial, biological, and geological processes. In the first part of this study, the well-known titration approach introduced by Gebauer and coworkers in 2008 s used to obtain reliable experimental dataset for the deep understanding of CaCO3 nucleation kinetics in supersaturated solutions over a broad range of pH and ionic strength conditions. In the second part, the effect of impurities, i.e., 1 mol% of Pb2+, was assessed in the same range of experimental conditions. Divalent lead has been shown to have an inhibitory effect in all ranges of the conditions tested except for pH 8 and low ionic strength (≤0.15 mol/L). Future investigations might take advantage of the methodology and the data provided in this work to investigate the effect of other system variables. The investigation of all the major variables and the assessment of eventual synergic effects could improve our ability to predict the formation of CaCO3 in complex natural systems.

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