The significant carbon footprint and energy demand of the photocatalytic ammonia system necessitates high catalytic activity, efficient catalyst recovery, and reuse under mild conditions. In this work, we demonstrate efficient visible-light-driven ammonia synthesis using metal-free thermally exfoliated carbon nitride (GCN-T) immobilized on a 3D-printed support (GCN-T/3D). Under visible-LED irradiation (435 nm) and mild heterogeneous reaction conditions, this sustainable, environmentally friendly photocatalyst facilitates improved nitrogen (N2) activation, emphasizing its potential for effective recovery and reuse in ammonia production. The GCN-T photocatalyst-based process generated 334 µmol.gcat−1 h− 1 ammonium (NH4+) solution when glycerol was used as a hole scavenger, which is approximately three times higher than the rates reported for other GCN-based catalysts. FTIR-ATR, photoluminescence, photoelectrochemical, and UV-Vis DRS analyses were conducted to characterize the prepared catalysts. BET analysis showed that applying a second thermal treatment to GCN material increased the pore volume, thereby improving N2 adsorption across the catalyst surface and photogenerated carrier separation. Remarkably, the 3D structure with the immobilized catalyst increased the rate of NH4+ generation and enabled at least 4 reutilization runs without loss of activity. An apparent quantum efficiency of 0.020
Optical detection of singlet oxygen in cells affects the investigated cells and potentially, photosensitization skews the observed results, since the generated singlet oxygen undergoes chemical reactions with cellular quenchers. For this reason, the illumination intensity has to be kept low during a measurement to avoid killing and destruction of the investigated cells. The scope of this paper is to show, that scanning detection can meet both, sufficient sensitivity and low illumination dose, for adherent cells in 6-well plates. The individual illumination dose for cells under investigation is reduced by distributing it among a large number of adherent growing cells. Adherent cell lines were investigated with regard to singlet oxygen production by means of simultaneous fiber-coupled irradiation at 635 nm and singlet oxygen phosphorescence detection. Singlet oxygen kinetics could be measured in two different cell types incubated with different photosensitizers, by scanning a major part of the area of a confluent layer of cells in a well. In each case, singlet oxygen signals kinetics could be observed and analyzed. Incubation with increasing amounts of photosensitizer did correlate to the determined signal amplitude and photosensitizer triplet decay times. Focused excitation and observation in combination with scanning across the whole well results in successful determination of singlet oxygen kinetics from incubated adherent cells without detaching them. Further development is required to reduce artifacts, likely originating from scattered excitation light.
Bone repair depends on a regulated macrophage-driven inflammatory response. Non-activated macrophages (M0) differentiate into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes in response to microenvironmental signals. This study evaluated, in vitro, the effects of photobiomodulation (PBM) on bone marrow-derived macrophage polarisation. Monocytes were isolated, differentiated into macrophages (M0), and induced to acquire M1- or M2-associated characteristics. Cells were irradiated using a PBM protocol for bone regeneration (equivalent dose of 2.1 E). Cells were analysed according to morphology, expression of M1 (iNOS, Tnf-α) or M2 markers (Arg1, Cd206), protein expression (iNOS and ARG1), and nitric oxide (NO) and reactive oxygen species (ROS) production. Data were analysed using 1-way analysis of variance or Student’s t-test (p ≤ 0.05). PBM promoted selective and transient modulation of inflammatory and metabolic markers in M0, M1, and M2 macrophages. Compared to non-PBM-treated cells, M1PBM cells had reduced NO levels, increased early ROS levels, and decreased gene and protein expression. In M2PBM cells, transient changes in NO and ROS production were detected, with reduced Cd206 expression and similar Arg1 expression, although increased ARG1 protein expression was detected compared to non-irradiated controls. In M0PBM cells, NO levels remained unchanged, while early ROS levels increased, accompanied by reduced iNos and Arg-1, and increased Cd206 expression. Under the selected parameters, PBM modulated macrophage inflammatory behaviour, but was insufficient to induce classical macrophage polarisation towards a specific phenotype. These findings suggest that modulation of macrophage-mediated inflammatory responses may contribute to the effects of this PBM protocol during bone repair. Illustrations were generated using the Illustrae AI-assisted illustration platform.
Artificial tanning devices expose users to ultraviolet radiation and are associated with an increased risk of skin cancer. To protect users, Swiss legislation, among other requirements based on the SN EN 60335-2-27, limits the total erythema effective irradiance of artificial tanning devices to 0.3 W/m^2 . Additionally, only UV-Type 3 devices may be used in unsupervised settings. From 2022 to 2024, Swiss cantonal authorities conducted a nationwide measurement campaign to assess compliance with the limits. For this, a portable measurement system, based on a stray-light-suppressing array spectroradiometer was developed and evaluated against precision double-monochromator measurements. The developed system achieved comparable accuracy while enabling rapid in-situ conformity assessments. Overall, 1’521 individual measurements were performed on 436 artificial tanning devices across Switzerland. While 66 % of the measured devices complied with the legal limit for the total erythema effective irradiance, only 38 % met the criteria of UV-Type 3 devices. After corrective actions on previously non-compliant devices, follow-up measurements showed that 50 % of all tested devices were compliant. The results demonstrate the suitability of the developed measurement system and reveal substantial compliance deficiencies, highlighting the need for continued inspection of artificial tanning devices.
Over the time, there has been a growing interest in the development of ecologically acceptable and sustainable technologies for modern organic synthesis in order to meet the demands of safe, economical, and renewable industrial productions. As a result, photocatalysis has revolutionized organic synthesis by offering innovative and sustainable functionalization of complex molecules. Accordingly, the visible light-promoted synthesis of chalcone derivatives has been highly advantageous in enabling eco-friendly chemical transformations, as it utilizes light as an abundant and non-toxic energy source. Chalcones are inherently versatile synthons in synthetic organic chemistry because of the α, β-unsaturated carbonyl system, which allows for a variety of molecular transformations. Thus, the present review summarized visible light-promoted transformations of chalcones to corresponding functionalized heterocyclic derivatives like aziridines, oxiranes, cyclobutanes, imidazo[2,1-b]thiazoles, urundeuvines, benzo[d][1,3]-oxazocines, pyrimidines, and sulfonated chromanes, which may be useful for biological and material science applications.
