308-nm excimer laser in the treatment of a localized recalcitrant form of perioral dermatitis: Case report

In the last two decades, 308-nm excimer laser has been increasingly recognized as a therapeutic alternative for several dermatological conditions, being currently FDA approved for the treatment of localized vitiligo and moderately severe localized psoriasis unresponsive to topical treatments. We describe the case of a 17-year-old with a recalcitrant form of dermatitis occupying the entire perioral region, previously unresponsive to several treatments, who was treated with 308-nm excimer laser with an excellent result. 308-nm monochromatic excimer laser has several advantages over other types of phototherapy, including lower UV dose exposure, shorter courses of therapy and a better sparing of adjacent tissue. Although infrequently used, 308-nm excimer laser certainly has a vast potential in Dermatology, particularly regarding recalcitrant and localized inflammatory conditions, such as the one we present.

Erythemal UV Dose and UV Index Measurement at 37th North Latitude and Its Possible Effects on Humans

In this study, UV irradiance and UV erythemal and UV index data of May, June, July and August measured in Adana (longitute=36 E, latitute=37 N altitute=140m) between 2013 and 2019 were analyzed. As a result of the analysis, the average of four months was 14.16 MED (2.9736 J/m2) and the highest value of these four months was calculated as 15.6 MED (3.276 J/m2) in July. The percentage frequency of the total daily UV dose was also calculated and it was determined that the region was under the effect of 70-80% high UV dose. In addition, it was calculated to have a high UV index according to local time (10.00-14.00). It was concluded that this situation poses a great risk for workers working in agricultural areas in the region and for people who spend their summer holidays by the sea. UV Dose-Ozone, UV Dose-temperature, UV Dose-humidity and Ozone-temperature correlations were also calculated. As a result of the comparison, it was found that there was an R= -0.64 correlation between UV-ozone, an R= -1.00 correlation between temperature and ozone, and a direct correlation of R= 0.60 between UV radiation and temperature.

Effect of turbidity on ultraviolet disinfection of domestic wastewater for agricultural reuse

Water treatment and reuse are fundamental because of the increasing demand for freshwater, especially in agriculture. Accordingly, this study evaluated the effects of turbidity of wastewater processed at the Effluent Treatment Station (ETE) of the UFSCar/Araras and of UV dose on microbial inactivation. The ETE treats up to 2000 L of wastewater daily from toilets and a university restaurant and has five components (grease box, septic tank, microalgae tank, upflow anaerobic filter, and wetlands). Pretreated effluents were used in the experiments, and sampling sites consisted of inspection boxes located after the wetlands. Sample collection, inspection, preservation, and analyses were performed according to standard methods. Sample turbidity was adjusted to 5, 50, 100, 200, and 300 nephelometric turbidity units (NTU), and UV doses of 7.2–28.8 mWs cm-2 were used. A 5 x 5 factorial design (five turbidity levels and five radiation doses) was used, totaling 25 treatments. Each treatment was performed in triplicate. The data were submitted to analysis of variance and Tukey’s test. The results showed that the increase in turbidity significantly decreased disinfection efficiency in samples with turbidity levels higher than 50 NTU. The microbial inactivation coefficients obtained here can be extrapolated to disinfection of wastewater with turbidity up to 300 NTU to eliminate thermotolerant coliforms. The UV sterilizer is feasible for wastewater treatment and its reuse in agriculture. Keywords: domestic effluent, sustainability, ultraviolet radiation, water reuse.

UV-Induced Formation of Ice XI Observed Using an Ultra-High Vacuum Cryogenic Transmission Electron Microscope and its Implications for Planetary Science

The occurrence of hydrogen atom-ordered form of ice Ih, ice XI, in the outer Solar System has been discussed based on laboratory experiments because its ferroelectricity influences the physical processes in the outer Solar System. However, the formation of ice XI in that region is still unknown due to a lack of formation conditions at temperatures higher than 72 K and the effect of UV-rays on the phase transition from ice I to ice XI. As a result, we observed the UV-irradiation process on ice Ih and ice Ic using a newly developed ultra-high vacuum cryogenic transmission electron microscope. We found that ice Ih transformed to ice XI at temperatures between 75 and 140 K with a relatively small UV dose. Although ice Ic partially transformed to ice XI at 83 K, the rate of transformation was slower than for ice Ih. These findings point to the formation of ice XI at temperatures greater than 72 K via UV irradiation of ice I crystals in the Solar System; icy grains and the surfaces of icy satellites in the Jovian and Saturnian regions.

Accessible, large-area, uniform dose photolithography using a moving light source

Photolithography is an essential microfabrication process in which ultraviolet (UV) light is projected through a mask to selectively expose and pattern a light-sensitive photoresist. Conventional photolithography devices are based on a stationary UV lamp and require carefully-designed optics to ensure that a uniform exposure dose is provided across the substrate being patterned. Access to such systems is typically limited to certain labs with domain-specific expertise and sufficient resources. The emergence of LED-based UV technologies has provided improved access to the necessary light sources, but issues with uniformity and limited exposure sizes still remain. In this work, we explore the use of a moving light source (MOLIS) for large-area lithography applications, in which the light source path speed, elevation, and movement pattern can be used to smooth out any spatial variations in source light intensity profiles, and deliver a defined and uniform cumulative UV exposure dose to a photoresist-coated substrate. By repurposing a 3D printer and UV-LED flashlight, we constructed an inexpensive MOLIS platform, simulated and verified the parameters needed to produce a uniform UV dose exposure, and demonstrate this approach for SU-8 microfabrication of features with dimensions relevant to many areas in biomedical engineering. The ready accessibility and inexpensive nature of this approach may be of considerable value to small laboratories interested in occasional and low-throughput prototype microfabrication applications.

Evaluation of Portable Rhodamine B Analyzer for Monitoring OH Radical Scavenging Demand in Ultraviolet Advanced Oxidation Processes

A portable OH radical scavenging demand analyzer that can be installed and operated on site was developed to measure water quality indicators that influence the generation of OH radicals from UV/hydrogen peroxide reactions to determine the UV dose and the hydrogen peroxide injection concentration. Rhodamine B (RhB) was used as an indicator for the continuous measurement of the OH radical scavenging demand of four samples with different water quality parameters using the rapid, easy, and real-time UV-Vis spectrophotometer method. The results demonstrated that the estimated rate constant for the RhB color decay rate resulting from direct UV photolysis was low enough to verify its suitability as a probe compound. The mean values of the OH radical scavenging demand for target water samples at different organic concentrations were 20,659 s−1 for plant N, 42,346 s−1 for plant C, 32,232 s−1 for plant Y, and 81,669 s−1 for plant B. Variations in the monitoring results for the target water treatment plants suggest that on-site OH radical scavenging demands should be considered to determine the UV dose and the hydrogen peroxide injection concentration for the UV advanced oxidation process.

Carotenoids from Persimmon (Diospyros kaki Thunb.) Byproducts Exert Photoprotective, Antioxidative and Microbial Anti-Adhesive Effects on HaCaT

Persimmon (Diospyros kaki Thunb.) fruits are a remarkable source of carotenoids, which have shown protective effects against UV radiation in bacteria, fungi, algae, and plants. The aim of this study was to analyze the photoprotection provided by an acetone extract, rich in carotenoids and obtained from byproducts derived from the persimmon juice industry, against UV-induced cell death in the keratinocyte HaCaT cell line. For this purpose, the cytotoxicity and phototoxicity of carotenoid extract, as well as its intracellular reactive oxygen species (ROS) scavenging and anti-adhesive activities towards HaCaT cells, were evaluated. The in vitro permeation test provided information about the permeability of the carotenoid extract. Persimmon extracts, rich in carotenoids (PEC), were absorbed by HaCaT keratinocyte cells, which reduced the UV-induced intracellular ROS production in treated cells. Thus, PEC exerted a photoprotective and regenerative effect on UV-irradiated HaCaT cells, and this protection was UV dose-dependent. No cytotoxic effect was observed in HaCaT cultures at the concentration tested. PEC treatment also stimulated the adhesion capacity of skin microbiome to HaCaT cells, while exhibiting a significant anti-adhesive activity against all tested pathogens. In conclusion, PEC showed potential for use as a functional ingredient in skin-care products.

The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: a systematic review of ultraviolet radiation

Respiratory viruses are capable of transmitting via an aerosol route. Emerging evidence suggests that SARS-CoV-2 which causes COVID-19 can be spread through airborne transmission, particularly in indoor environments with poor ventilation. Heating, ventilation, and air conditioning (HVAC) systems can play a role in mitigating airborne virus transmission. We conducted a systematic review of the scientific literature examining the effectiveness of HVAC design features in reducing virus transmission; here we report results for ultraviolet (UV) radiation. Following international standards for systematic reviews, we conducted a comprehensive search and synthesized findings from 32 relevant studies published between 1936 and 2020. Research demonstrates that: viruses and bacteriophages are inactivated by UV radiation; increasing UV dose is associated with decreasing survival fraction of viruses and bacteriophages; increasing relative humidity is associated with decreasing susceptibility to UV radiation; UV dose and corresponding survival fraction are affected by airflow pattern, air changes per hour, and UV device location; and UV radiation is associated with decreased transmission in both animal and human studies. This comprehensive synthesis of the scientific evidence examining the impact of UV radiation on virus transmission can be used to guide implementation of systems to mitigate airborne spread and identify priorities for future research.

Degradation of 2,6-dichloro-1,4-benzoquinone by advanced oxidation with UV, H2O2, and O3: parameter optimization and model building

Halobenzoquinones are disinfection by-products with cytotoxicity, carcinogenicity, and genotoxicity. In this study, we investigated the removal of the HBQ 2,6-dichloro-1,4-benzoquinone (DCBQ) from water using advanced oxidation processes. The removal of DCBQ from water using UV, H2O2, and O3 advanced oxidation processes individually was not ideal with removal rates of 36.1% with a UV dose of 180 mJ/cm2, 32.0% with 2 mg/L H2O2, and 57.9% with 2 mg/L O3. Next, we investigated using the combined UV/H2O2/O3 advanced oxidation process to treat water containing DCBQ. A Box–Behnken design was used to optimize the parameters of the UV/H2O2/O3 process, which gave the following optimum DCBQ removal conditions: UV dose of 180 mJ/cm2, O3 concentration of 0.51 mg/L, and H2O2 concentration of 1.76 mg/L. The DCBQ removal rate under the optimum conditions was 94.3%. We also found that lower humic acid concentrations promoted DCBQ degradation, while higher humic acid concentrations inhibited DCBQ degradation.