Photochemistry and Photobiology最新文献

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 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.

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.

Inorganic semiconductors such as TiO₂ absorb ultraviolet light to promote reactions. However, sunlight consists mainly of visible light, and so the development of photocatalysts that can use visible light is being actively researched. Density functional theory (DFT) calculations previously showed that the introduction of formyl, carboxyl, and carboxyethyl groups into picene can absorb visible light and generate hydrogen via the decomposition of water. In this study, these substituted picene derivatives were employed as photocatalysts, and their water photolysis activities were evaluated under visible light irradiation. All three picene derivatives were active photocatalysts, with hydrogen production activities decreasing in the order of: picene-13-carbaldehyde (CHO-picene) > picene-13-carboxylic acid (COOH-picene) ≈ Ethyl picene-13-carboxylate (COOEt-picene) > picene. Subsequently, the effects of the three functional groups on the hydrogen production activity in the water photolysis reaction were investigated in further detail. The effects of the functional groups were found to be in accordance with the Hammett equation, wherein a greater electron-withdrawing property led to a higher hydrogen production activity.

Reducing airborne disease transmission is a public health goal. Far-UVC light, defined as 200-235 nm, is a promising technology to inactivate viruses within occupied spaces. This work examines state of the art far-UVC emitting LEDs, with a center emission wavelength of 233 nm, for virus inactivation efficacy and for DNA damage to skin models. The LEDs were used to expose an aerosolized surrogate of SARS-CoV2, the human coronavirus OC43, and survival results estimated a susceptibility constant of k_233-aerosol = 4.0 ± 0.2 cm²/mJ, which corresponds to a D₉₀ of 0.58 mJ/cm². HCoV-OC43 was also exposed after drying on a plastic or glass surface, and inactivation results estimated susceptibility values of k_{1_233-plastic} = 6.7 ± 3.8 cm²/mJ and k_{1_233-glass} = 7.2 ± 3.0 cm²/mJ which were not significantly different. For safety evaluation, human skin biopsies exposed to 100 mJ/cm² from the 233 nm LEDs indicated only 8% of the epidermal cells were positive for DNA damage, whereas the same dose from a 254 nm lamp showed damage in 45% of epidermal cells. A radiant exposure of 100 mJ/cm² from the 233 nm LEDs did not produce DNA double strand breaks within the skin biopsies. These tests for the safety and efficacy of a 233 nm far-UVC LED system provide support for the continued development of far-UVC LED sources.

Photobiomodulation (PBM) has demonstrated potential in promoting peripheral nerve regeneration. However, there is a limited and inconclusive study on the application of light-emitting diode (LED) for nerve injury repair. In this study, we designed an 807-nm LED device with high luminous uniformity to investigate the effects of LED-based PBM on peripheral nerve injury repair. RSC96 cells were utilized as the target cells and optimal light parameters were selected based on ATP concentration, CCK-8 assays, PCR, and immunofluorescent staining. One-way analysis of variance and Student's t-test was used for statistical tests. LED irradiation at 10 mW/cm² for 30 min effectively enhanced Schwann cell proliferation, neurotrophic factor secretion, and MBP synthesis. To translate the cellular light parameters for animal studies, the transmittance through freshly obtained rat skin and biceps femoris muscle was assessed, and the transmittance was approximately 30%. After directly daily irradiating the sciatic nerve injury area in rats for 21 days at 33 mW/cm² for 30 min, we used gait analysis, immunofluorescence staining, muscle wet weight ratio, Masson staining, and transmission electron microscopy to evaluate nerve recovery. LED irradiation significantly improved sciatic nerve index, increased MBP staining intensity, and enhanced myelin sheath thickness, nerve diameter, and axon diameter. These results indicated the feasibility of LED-based PBM as a treatment method for peripheral nerve injuries.