A checklist for assessing the methodological quality of concurrent tES-fMRI studies (ContES checklist): a consensus study and statement

Background: Low intensity transcranial electrical stimulation (tES), including alternating or direct current stimulation (tACS or tDCS), applies weak electrical stimulation to modulate the activity of brain circuits. Integration of tES with concurrent functional magnetic resonance imaging (fMRI) allows for the mapping of neural activity during neuromodulation, supporting causal studies of both brain function and tES effects. Methodological aspects of tES-fMRI studies underpin the results, and reporting them in appropriate detail is required for reproducibility and interpretability. Despite the growing number of published reports, there are no consensus-based checklists for disclosing methodological details of concurrent tES-fMRI studies. Objective: To develop a consensus-based checklist of reporting standards for concurrent tES-fMRI studies to support methodological rigor, transparency, and reproducibility (ContES Checklist). Methods: A two-phase Delphi consensus process was conducted by a steering committee (SC) of 13 members and 49 expert panelists (EP) through the International Network of the tES-fMRI (INTF) Consortium. The process began with a circulation of a preliminary checklist of essential items and additional recommendations, developed by the SC based on a systematic review of 57 concurrent tES-fMRI studies. Contributors were then invited to suggest revisions or additions to the initial checklist. After the revision phase, contributors rated the importance of the 17 essential items and 42 additional recommendations in the final checklist. The state of methodological transparency within the 57 reviewed concurrent tES-fMRI studies was then assessed using the checklist. Results: Experts refined the checklist through the revision and rating phases, leading to a checklist with three categories of essential items and additional recommendations: (1) technological factors, (2) safety and noise tests, and (3) methodological factors. The level of reporting of checklist items varied among the 57 concurrent tES-fMRI papers, ranging from 24% to 76%. On average, 53% of checklist items were reported in a given article. Conclusions: Use of the ContES checklist is expected to enhance the methodological reporting quality of future concurrent tES-fMRI studies, and increase methodological transparency and reproducibility

Mechanisms of Direct Photolysis of Biocides Based on Halogenated Phenols and Anilines

The Handbook of Enviromental Chemistry. Edition SpringerThe halogenated phenols and anilines are the parent chromophores of a number of widely used pesticides, among them phenoxyacetic acid and phenylurea derivatives, and of other biocides. The direct photolysis of the substances in the environment has become a subject of increasing interest. In the first part of this review, investigations of the photochemistery of halogenated phenols and anilines carried out during the last decade are summarized. The second part is concerned with corresponding studies on biocides. The phototransformation mechanisms of these compounds have been found to share many common features. In particular, two kinds of heterolytic dehalogenation processes, aromatic carbon-halogen photohydrolysis on the one hand and formation of triplet carbenes or aryl cations on the other, have been described for many systems. The mechanistic knowledge gained in the investigations of model compounds is increasingly brought to bear on actual environmental situations

Photolysis of 4-chlororesorcinol in water: competitive formation of a singlet ketene and a triplet carbene

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Photoelectrochemical properties of sol-gel and particulate TiO2 layers

Polarization curves on irradiated TiO2 layers were measured in various electrolytes, namely sodium hydroxide, sulphuric acid, oxalic acid and potassium oxalate. Photocurrents measured in 0.1M NaOH are very small and decrease with increasing number of Degussa P25 TiO2 layers. Photocurrents for sol-gel TiO2 layers in 0.1M NaOH are about five times higher than for P25 TiO2 layers and increasing with number of layers. The same holds for Na2SO4, but in H2SO4 the difference between P25 and sol-gel diminishes, however the sol-gel layers still show the higher currents. In solutions of oxidizable substrates the trend is inversed: P25 layers show higher currents, with a steep increase with concentration of solute. The shape of the polarization curves was interpreted in terms of response time to irradiation and photocurrent depletion. Degradation experiments demonstrated that the effect (and advantage) of biasing the electrode depends on adsorption properties of substance and surface area of electrode material

Initiators Based on Benzaldoximes: Bimolecular and Covalently Bound Systems

Typical bimolecular photoinitiators (PIs) for radical polymerization of acrylates show only poor photoreactivity because of the undesired effect of back electron transfer. To overcome this limitation, PIs consisting of a benzaldoxime ester and various sensitizers based on aromatic ketones were introduced. The core of the photoinduced reactivity was established by laser flash photolysis, photo-CIDNP, and EPR experiments at short time scales. According to these results, the primarily formed iminyl radicals are not particularly active. The polymerization is predominantly initiated by C-centered radicals. Photo-DSC experiments show reactivities comparable to that of classical monomolecular type I PIs like Darocur 1173

Photoinitiators with β-Phenylogous Cleavage: An Evaluation of Reaction Mechanisms and Performance

Bimolecular photoinitiators based on benzophenone and <i>N</i>-phenylglycine ideally overcome limitations of classical two-component systems, such as the possibility of deactivation by a back electron transfer or the solvent cage effect. Furthermore, if they are covalently linked, loss of reactivity by diffusion limitation could be reduced. Here we show that such an initiator displays unusually high photoreactivity. This is established by photo-DSC experiments and mechanistic investigations based on laser flash photolysis, TR-EPR, and photo-CIDNP. The β-phenylogous scission of the C–N bond is highly efficient and leads to the production of reactive initiating radicals at a short time scale