Photochemistry and Photobiology最新文献

Electronic absorption and fluorescence properties of a red-emission firefly luciferin analog, seMpai, which is water-soluble and shows a neutral pH, were revealed by quantitative spectroscopic measurements in aqueous solutions of pH 2-10. They were analyzed by density functional theory (DFT) calculations, time-dependent DFT calculations, and vibrational analyses using the neutral form of seMpai and its conjugate acids and bases. In a pH 8 solution, which is commonly used for firefly bioluminescence, seMpai showed an absorption maximum at 380 nm. From the theoretical absorption spectra and pH dependence of the normalized concentrations of the neutral form of seMpai and its conjugate acids and bases, it was found that the most abundant chemical species at pH 8 is the carboxylate anion, and the 380-nm absorption band was assigned as the $\pi$ - $\pi$ * transition of this anion. The fluorescence spectrum of seMpai in the pH 8 aqueous solution showed an emission maximum at 534 nm for 380-nm excitation. According to the theoretical pH dependence of the normalized concentrations and theoretical absorption and fluorescence energies of the chemical forms of seMpai, the most reasonable fluorescence pathway at pH 8 is the emission from the first excited singlet state S₁ of the carboxylate anion through its excitation.

A phenanthridine-based fluorogenic probe 5-(2-(prop-2-yn-1-yloxy)phenyl)-7,8,13,14-tetrahydrodibenzo[a,i]phenanthridine (SAAPH) has been successfully synthesized and characterized through nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS) spectral analyses. A low detection limit was attained for identifying Ru³⁺ at a concentration of 151pM with a minimal reaction time of 10 s. Furthermore, incorporating ethylenediaminetetraacetic acid (EDTA) into SAAPH + Ru³⁺ rendered SAAPH a reversible sensor. Fascinatingly, the fluorescence signal of SAAPH was Turn-ON by the interaction with Ru³⁺ resulting in the noticeable emission change from colorless to blue with an emission enhancement fold of 12. The detection mechanism of SAAPH was initiated by an Intramolecular Charge Transfer (ICT), wherein electrons were transferred from the electron-rich phenanthridine moiety containing the propargylic group to the electron-deficient Ru³⁺. Additionally, paper strips were used for fluorescence detection of Ru³⁺. Further, Ru³⁺ was detected in environmental water samples and HeLa cells. Consequently, SAAPH demonstrates a lower detection limit than other fluorescent probes and exhibits strong selectivity and sensitivity toward Ru³⁺.

This paper is a highlight of the paper by Shahbazi et al. in this issue of Photochemistry and Photobiology. In that systematic review with meta-analysis study, the authors selected a total of 47 papers for the systematic review, and from those, 14 papers were eligible for the meta-analysis. The papers included were based on the adjunctive treatment of peri-implant diseases (PIDs) by the use of photodynamic therapy (PDT), photobiomodulation (LLLT), hyperlight, and high-power lasers in combination with mechanical debridement (MD) used as routine treatment. The clinical findings promoted by the adjunctive treatment based on the phototherapies over the peri-implant diseases were investigated and demonstrated through the literature retrieved and discussed. Photodynamic therapy, photobiomodulation, hyperlight, and high-power lasers used as adjunctive treatments to the mechanical debridement rendered significant impact on different clinical outcomes for both mucositis and peri-implantitis diseases. Photodynamic therapy was the most common phototherapy used in the different studies, and it was capable of contributing to the improvement of important clinical parameters such as: BL (Bone Loss), BoP (Bleeding on Probing), CAL (Clinical Attachment Loss), and PD (Probing Depth); however, these improvements seem to be restricted to short-term evaluation. Yet, after long-term follow-ups, the combined use of phototherapies seems to be similar to those from the conventional treatment, especially MD alone. Among the adjunctive phototherapies discussed by Shahbazi et al., PDT and LLLT seem to be more realistic to be used in the daily clinical setting, especially because they can be more accessible to the clinicians.

Jogging is one of the most popular recreational sport activities over four decades and is done at almost all ages to keep fitness and health. Joggers are exposed to solar UV radiation (UVR) and, due to enhanced heat production by physical activity, body coverage by clothes is reduced. This may imply a health risk due to overexposure. However, little research has been undertaken so far to estimate UVR exposure during jogging. Therefore, UVR exposure was measured at seven body sites during jogging under cloud-free conditions for solar elevations between 20° and 60°. Results show that the top of the shoulder is the most exposed body site by receiving 80% of ambient UVR on average and up to 110% under certain conditions. All other body parts receive up to 55% on average and up to 85% in special cases. This indicates further that monotonous body alignment to the sun holds a higher risk than a frequently alternating alignment. Assuming the longest recommended duration for cardiovascular beneficial jogging of 50 min, photosensitive persons need protection of the shoulders from a UV index of 2 onward on an unvaried path and from a UV index of 3 on an all-directional path. Further, results show that measurements of UVR exposure possess an uncertainty of ±15% including mounting.

Personal solar ultraviolet radiation (UVR) exposure has positive and negative impacts on human health. Excess solar UVR exposure can be avoided through safe sun practices such as using sun protection and avoiding unprotected outdoor exposure when solar UVR levels are high. The shadow rule indirectly determines the sun's altitude by observing the length of a person's shadow during the course of the day. When the shadow cast by the sun on a horizontal surface is shorter than the height of the person casting the shadow, the solar UVR intensity is high and is deemed to have more risk. The magnitude of this risk depends on factors such a skin type, sun protection used etc. The UV Index is a standardized measure to describe the intensity of solar UVR with respect to the human action spectrum for sunburn. It is frequently reported in weather forecasts aimed at the public. Here, we demonstrate the potential utility of the shadow rule and how it may be understood in relation to the UV Index in a subtropical southern hemisphere setting. Its use as a simple awareness tool for sun protection in locations where the UV Index is not made public has value in promoting sun exposure awareness and reducing personal exposure risk.

This study aimed to systematically review the data on interventions involving adjunctive photochemical therapy in treating peri-implant mucositis (PIM) and peri-implantitis (PI). The electronic search was conducted through six databases in October 2023, seeking studies relying on any kind of adjunctive photochemical therapy in treating inflammatory peri-implant diseases (PIDs). To showcase the effect size, mean differences along with 95% confidence intervals were utilized. Forty-seven studies were deemed eligible for qualitative synthesis, 14 of which were included in the meta-analysis. Low-level light therapy and photodynamic therapy led to enhanced improvements in clinical and radiographic indices, such as bone level (BL), bleeding on probing (BoP), clinical attachment level (CAL), and probing depth (PD), during the 3-month follow-up. However, the differences in efficacy between treatments incorporating adjunctive photochemical therapy and those relying solely on mechanical debridement, considered the gold standard, lessened over extended follow-up periods of 6, 9, and 12 months. Significant differences were observed when comparing the treatment outcomes following adjunctive photochemical therapy between obese and smoker patients with healthy subjects. Incorporating adjunctive photochemical therapy for PID treatment might improve clinical and radiographic parameters in a short-term follow-up of 3 months, but longer-term benefits appear comparable to routine treatments.

This in vitro study aimed to determine if simultaneous irradiation with 660 and 808 nm wavelengths enhances keratinocyte migration and alters keratin expression. Keratinocytes were exposed to either 660 nm or 808 nm irradiation alone, as well as to both wavelengths simultaneously using a laser device with the same energy parameters (2 J, 22.22 J/cm²). Cell viability, migration, and keratin expression (K1, K10, K5, and K14) were assessed in a scratch model assay. After 24 h of PBM, the simultaneous group showed higher cell viability compared with the control and the irradiated groups with one wavelength (660 and 808 nm groups). Simultaneous irradiation also resulted in a smaller scratch area compared with the control and 660 nm groups. The frequency of cells positive for K1/K10 at the wound border was lower after dual irradiation, while cells positive for K5/K14 at the wound periphery were more frequent after simultaneous irradiation. These results suggest a potential increase in the population of less-differentiated keratinocytes following 660-808 nm dual emission. In conclusion, combined irradiation improved cell viability and migration, potentially leading to a shift in keratinocyte differentiation. This dual-wavelength effect may help stimulate the reepithelization process in the tissue repair.

The kinetics of the interaction of several cannabinoids with singlet oxygen have been examined in acetonitrile solution using laser flash photolysis techniques and using xanthone as a singlet oxygen sensitizer. Typical rate constants for these Type 2 reactions are in the 1-7 × 10⁷ M^-1 s^-1 range and are in accordance with typical reactivities for phenolic compounds. Protection of the phenolic function reduces the reactivity by approximately a factor of five, thus confirming that singlet oxygen quenching is dominated by the phenolic group.

The excessive use of artificial light is altering the natural light-dark cycles, consequently impacting animal behavior and physiology. Dim light at night (dLAN) can disrupt migratory patterns, alter hormone levels, and impact breeding success in birds. The present research aims to address the effects of dLAN on the metabolic and reproductive tissues of migratory redheaded bunting (Emberiza bruniceps). For this, buntings under short winter-like days (10L:14D) were exposed to either dark nights (D = 0.00014 W/m²) or dLAN (D = 0.058 W/m²), and their locomotor activity, body mass, fat score, food intake, testicular volume, and plasma testosterone levels were measured. The histological architecture of the muscle, intestine, testis, and liver tissues was assessed. Birds exposed to dark nights confined their activity to the daytime only, whereas the dLAN group showed nocturnal activity and initiated Zugunruhe (nighttime restlessness). The body mass, food intake, fat score, and testicular volume significantly increased under dLAN. Histomorphometry revealed increased muscle width, epithelium thickness, and lumen diameter in the testis, proximal and distal muscularis thickness in the intestine, hepatic lipid droplet size, and decreased proximal villi length and intestinal diameter under dLAN. Further, plasma testosterone levels also increased under dLAN. Our results suggest that dLAN can induce migration-linked phenotypes even under non-stimulatory short days leading to mistimed seasonal activities.

The presence of microbial biofilms on equipment surfaces is a recurrent problem in the food industry. To reduce the risk of biofilm development, a preventive method based on photoactive antibacterial surfaces is proposed. In the present study, crystalline rutile form titanium dioxide (TiO₂) thin layers are deposited on stainless steel substrates by RF sputtering under reactive plasma. Such layers are assessed for their bactericidal activity on two strains of Listeria monocytogenes. After 1 h of irradiation under UV-A at 365 nm, a decrease of 2 log of the number of adherent Listeria cells is observed. Analysis with scanning electron microscopy suggests damages to the bacterial walls. Moreover, the peroxidation of the membrane lipids of L. monocytogenes by the radical species formed by photocatalysis is confirmed since malondialdehyde was detected after irradiation. Furthermore, the present work investigates the role of the redox species generated by photocatalysis. Indeed, experiments carried out in the presence of scavenger molecules (DMSO, EDTA-2Na, superoxide dismutase) show that holes are the main redox species involved in the antibacterial activity of the deposited layers. These results allow a better understanding of the role of the redox species generated by the photocatalytic activity of the rutile TiO₂ thin layers.