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In very recent years, ultraviolet (UV) persistent luminescent materials (PLMs) have attracted widespread attention due to their potential biological applications. However, owing to the lack of suitable emitters and hosts, the design and development of excellent UV PLMs remain challenging. Here, we report a new Gd-based PLM NaGdGeO4:Bi3+ with super-long UVA persistent luminescence (PersL). By further co-doping Li+ ions to increase the concentration of traps, the UVA PersL intensity of NaGdGeO4:Bi3+ is increased by 5.5 times. The optimal NaGdGeO4:Bi3+,Li+ exhibits excellent UVA PersL and can persist for more than 200 h. Moreover, the phosphor NaGdGeO4:Bi3+,Li+ also exhibits photostimulated property with a red LED or NIR laser excitation after the long-term decay, and can be activated by X-ray. This promising Gd-based UVA PLM is expected to have potential applications in biomedicine through triggering photocatalysts or photosensitizers by its UVA PersL to achieve photodynamic therapy and its potential ability of magnetic resonance (MR) imaging due to Gd3+ ions as MR imaging probe containing in the host NaGdGeO4.

To investigate the effects of iontophoresis–ultraviolet A (UVA) cross-linking (CXL) with hypotonic riboflavin solution on the ultrastructural changes in the lamellae, collagen fibrils (CFs), and proteoglycans (PGs) in the central and peripheral stroma of the human corneal buttons. The iontophoresis method was used for the trans-epithelial application of hypotonic riboflavin in ex vivo corneal culture for 5 min. The corneas were irradiated using three methods: Group 1 (G1), a UVA irradiance of 3 mW/cm2 for 30 min; Group 2 (G2), a UVA irradiance of 10 mW/cm2 for 9 min; Group 3 (G3), without UVA irradiation. Three untreated corneas were used as controls (G0). After the CXL procedure, the corneas were processed for electron microscopy. The CF diameter and PGs in each sample were analyzed using the iTEM program. The keratocyte organelles and stromal architecture in the peripheral cornea were better preserved than those in the central cornea. In G1 and G2, the mean CF diameter in the peripheral cornea was significantly higher than that in the central cornea. In G3, the CF diameter in the central cornea was significantly larger than that in the peripheral cornea. Furthermore, differences in PG area size were observed between the central and peripheral corneas in all groups. Riboflavin + UVA application at 3 mW/cm2 for 30 min and 10 mW/cm2 for 9 min was a suitable method of CXL; however, 3 mW/cm2 for 30 min improved the organization and size of the collagen fibrils. CXL treatment applied at the periphery was more effective than that applied at the center.

To evaluate the long-term visual, refractive, tomographic, and aberrometric outcomes of corneal collagen crosslinking (CXL) with or without hypoosmolar riboflavin solution in the treatment of progressive keratoconus patients with thin corneas. Charts of consecutive progressive keratoconus patients with thinnest corneal thickness less than 470 µm who underwent corneal collagen CXL with or without hypoosmolar riboflavin solution and using a standardized protocol for treatment and examinations were analyzed retrospectively. The indication for hypoosmolar riboflavin use was a central corneal thickness less than 400 µm as measured by ultrasound pachymetry after epithelial debridement and before exposure to ultraviolet A (UVA) light. Uncorrected distance visual acuity (UDVA), best spectacle-corrected distance visual acuity (CDVA), manifest refraction, slit lamp biomicroscopy, corneal tomography, corneal aberrometry, and endothelial cell counts were evaluated at baseline and yearly at all postoperative follow-up examinations until month 36. The outcomes of corneal CXL procedure performed using hypoosmolar riboflavin were compared to those performed using the standard procedure. Twenty-three eyes (19 patients) were treated using hypoosmolar riboflavin application, and 30 eyes (28 patients) were treated using the standard procedure. Compared to baseline, the mean UDVA, CDVA, and keratometric readings improved statistically significantly in both groups at postoperative year 3, without any statistically significant between-group differences. Progression was not observed in any patient eye in either group. No significant endothelial cell loss and no sight threating complication were observed in any patient eye. At 3 years follow-up, the safety and efficacy of CXL using hypoosmolar riboflavin solution seems to be similar to that of standard CXL in progressive keratoconic eyes with thin corneas. The visual, refractive, keratometric, tomographic and aberrometric outcomes of the two procedures were comparable, as well.

Most of the plant species found in the high mountain ecosystems of the tropics is unique and exceptional, because they have developed complex adaptations to survive in extreme environmental conditions, such as high levels of UVR and low temperatures of these ecological environments. In an exploratory study carried out on some plants of this ecosystem, we found that one of the most promising species was the Pentacalia pulchella (Kunth) Cuatrec. (Asteraceae) an endemic plant of Colombia, which grows between 2500 and 3500 m.a.s.l. Therefore, the objective of this work was to evaluate the photoprotective, antioxidant, and chemical composition of extracts from the leaves of P. pulchella. Extracts showed good absorption coefficients in UVA-UVB, high content of total phenols, with antioxidant activity comparable to that obtained with butylhydroxytoluene (BHT). Finally, the formulation labeled “7” with 10% extract presented adequate sensory characteristics for topical use, good in vitro photoprotection values in the UVA–UVB range (SPF (Sun Protection Factor): 7.3 ± 0.9, UVAPF (Ultraviolet A Protection Factor): 5.3 ± 0.6, λc 376), and antioxidant activity. Results obtained allow us to suggest that the extract of P. pulchella has a high potential as a source of new natural solar filters.

Objective: To evaluate changes in visual acuity and contrast sensitivity in patients with keratoconus after corneal collagen cross-linking. Study Design: Quasi-experimental study. Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan, from May 2019 to Apr 2020. Methodology: A total of 48 eyes of 30 patients with progressive keratoconus were included in this study. Baseline uncorrected distance visual acuity, corrected distance visual acuity and contrast sensitivity were recorded, following which transepithelial corneal collagen cross-linking with topical riboflavin and ultraviolet A light was performed. Uncorrected distance visual acuity, corrected distance visual acuity and contrast sensitivity measurements were repeated and recorded 6-months postoperatively. Results: Mean preoperative uncorrected distance visual acuity was 0.56 ± 0.27 logarithm of the minimum angle of resolution which improved to 0.51 ± 0.26 at 6 months after the procedure (p=0.002). Mean corrected distance visual acuity was 0.30 ± 0.19 preoperatively, improving to 0.24 ± 0.18 (p=0.001) at 6 months after corneal collagen cross-linking, thereby depicting a statistically significant improvement. Treated eyes also showed a significant improvement in contrast sensitivity (p=0.001) of 0.05 ± 0.08 logarithmic units of contrast sensitivity, from a mean preoperative contrast sensitivity of 1.72 ± 0.10 to 1.77 ± 0.09 when evaluated 6 months after corneal collagen cross-linking. Conclusion: Corneal collagen cross-linking is a promising advancement in the treatment of keratoconus. It was found effective in significantly improving visual acuity as well as contrast sensitivity, thus enhancing visual outcomes in keratoconus.

Sunscreens have been on the market for many decades as a means of protection against ultraviolet-induced erythema. Over the years, evidence has also shown their efficacy in the prevention of photoaging, dyspigmentation, DNA damage, and photocarcinogenesis. In the USA, most broad-spectrum sunscreens provide protection against ultraviolet B (UVB) radiation and short-wavelength ultraviolet A (UVA) radiation. Evidence suggests that visible light and infrared light may play a role in photoaging and should be considered when choosing a sunscreen. Currently, there is a paucity of US FDA-approved filters that provide protection against long UVA (> 370 nm) and none against visible light. Additionally, various sunscreen additives such as antioxidants and photolyases have also been reported to protect against and possibly reverse signs of photoaging. This literature review evaluates the utility of sunscreen in protecting against photoaging and further explores the requirements for an ideal sunscreen.

Introduction: Clean surroundings present lesser chances of catching Novel Coronavirus. Ultraviolet A (UVA, black light) flashlights can reveal things which the eye may miss but hardly anything is documented on the internet about UV and Covid-19 Pandemic when it comes to hygiene of inanimate objects. This report explores how one can detect uncleanliness using a UV flashlight. The formulated hypothesis questions several scenarios when this gadget could prove useful. Examples include: schools, workplace, childcare centres, bars, restaurants, hotels, public restrooms, hospitals, elderly homes, public transport and items like gloves and stretchers. Materials and methods: A clean ceramic bathroom tile was selected and photographed. UVA was emitted on the same tile using a UV flashlight and at the same time a small part was cleaned with a single stroke of a wet wipe and photographed again. External light was undimmed. Results: On comparison, the tile revealed that it was not clean enough because fluorescent green streaks were visible. A cleaner stripe was made after just one stroke with a wet wipe. Another observation showed that tile spacing can be problematic when cleaning. Conclusion: Despite some limitations, a UV flashlight may be useful for the visual monitoring of cleaning completion on high touch surfaces.

Purpose of review Corneal collagen crosslinking (CXL) is a minimally invasive treatment that can stabilize corneal ectatic disorders including keratoconus, pellucid marginal degeneration, or postrefractive surgery ectasia. The benefits of CXL have been well documented. New research is focused on modifying current treatment protocols with the goals of maximizing corneal stability while also shortening overall procedure time. Recent findings Accelerated CXL protocols have the goal of delivering the same ultraviolet A intensity as conventional protocols, but over a shorter time period. Accelerated protocols have shown success to date, but there are concerns for long-term corneal stability. Pulsed protocols may increase the long-term efficacy of the accelerated designs. In addition, transepithelial crosslinking protocols have been designed with the goal of reducing postoperative pain and lower the risk of infectious complications of epithelial-off conventional protocols. Summary Newer CXL protocols attempt to make the procedure safer and more effective. Current research is promising, but long-term studies are essential to understand how the new protocols may affect corneal stability.

The photo-oxidation of arsenite (As(III)) in solution containing Suwannee River fulvic acid (SRFA) under the ultraviolet A (UVA) irradiation (λmax = 365 nm) was studied. In a solution containing 100.0 μg·L−1 As(III) and 10.0 mg·L−1 SRFA at pH 3.0, SRFA induced As(III) photo-oxidation by producing the triplet excited state of SRFA (3SRFA*) and hydroxyl radical(HO˙). Approximately 82% of As(III) oxidation was attributed to HO˙ which depended strongly on HO2˙/O2˙−. The remaining 18% of As(III) oxidation was attributed to the direct reaction between As(III) and 3SRFA*. The photo-oxidation of As(III) was significantly affected by solution pH. Excess SRFA inhibited As(III) photo-oxidation. The addition of a low concentration of ferric ions retarded the photo-oxidation of As(III) due to the poor photo-activity of Fe(III)-SRFA complexes. In contrast, the addition of ferric ions at high concentration greatly accelerated As(III) photo-oxidation because of the high photo-activity of Fe(III)–OH complexes. The fractions of SRFA with different molecular weight showed different oxidizing capacities under UV irradiation which was possibly related to the different contents of phenolic OH groups. The findings have important environmental implications for the photo-transformation behavior of As(III) in natural surface waters containing dissolved organic matter, especially acidic waters.

Psoriasis is a chronic, recurrent, and immune-mediated inflammatory disease that affects 2–3% of the world population. The present study aimed to evaluate serum folate level before and after oral PUVA therapy in psoriatic patients. Patient and methods: A total of 40 psoriatic patients without any other morbidities (age ranged from 19 to 63 years, including 20 males and 20 females), All the patients recieved oral 8-methoxypsoralen at a dose of 0.6 mg/kg, followed 2 hours later by ultraviolet A exposure (oral PUVA therapy), For each patient the therapy will be twice weekly for eight weeks. Patients in the PUVA group were treated twice times weekly with a starting dose of 2 J/cm2, increasing by 20% each session, to a maximum of 15 J/cm2 per dose. Patients underwent up to 16 sessions. The dosage was adjusted if patients developed erythema. We have measured serum folate levels at baseline and after oral PUVA exposure. Also we use PASI score as objective method to visualize the relationship between improvement of psoriasis and changes in folate serum levels at baseline and after 16 exposures to PUVA for 8 weeks along with subjective methods which were done by photography and adverse effects were also reported. Results: There is statistically significant decrease of folic acid level after 16 sessions of phototherapy by average 20%. According to PASI score, Our results shows that there is statistically significant improvement in PASI score after phototherapy by average 60% .Conclusion: Folate deficiency should be evaluated and corrected in the patients, as it may be aggravated by UV therapy.

Background Patients with skin of color are at risk for skin cancer, pigmentary disorders, and photo-exacerbated conditions but find it challenging to use sunscreens on the market that leave an obvious residue on their skin. Objective The objective of this study was to examine sunscreen recommendations from the popular press and from practicing dermatologists for patients with skin of color. Methods We queried the Google search engine with the following search terms: “Sunscreen” with “skin of color,” “dark skin,” “black skin.” For comparison, we also searched for “sunscreen” with “white skin,” “pale skin,” and “fair skin.” We conducted an anonymous survey regarding sunscreen recommendations among dermatology trainees and board-certified dermatologists. Results Websites with recommendations on sunscreens for patients with skin of color compared with sunscreens for white or fair skin were more likely to recommend chemical sunscreens (70% vs. 36%) and more expensive products (median: $14 vs. $11.3 per ounce), despite the lower sun protection factor level (median: 32.5 vs. 50). In our survey study, dermatologists were overall cost-conscious and felt that sun protection factor level, broad spectrum (ultraviolet A/B protection), and price were the most important features of sunscreens for their patients. Cosmetic elegance was deemed least important. Dermatologists overall counseled patients with skin of color less on sunscreen use, and 42.9% reported that they either never, rarely, or only sometimes take patients’ skin type into account when making sunscreen recommendations. Conclusion These data represent an area for growth within dermatology to improve culturally competent care by gaining familiarity with sunscreen types and formulations that are geared toward patients with skin of color.

Background With the global sunscreen market expected to reach $24.4 billion worldwide by 2029, this demonstrates the increasing awareness of the damaging effects of sunlight. Sunscreen has been gradually evolving, and new photoprotective ingredients are continuing to be produced in response to growing scientific evidence on the effect of solar radiation on the skin. Aims This literature review aims to provide an updated view of the history of sunscreens. Methods A literature search was conducted with the keywords "Sunscreen, history, regulation, ultraviolet A, ultraviolet B, visible light" from PubMed, Medline, and online search engines. Results Humankind has always found ways to provide photoprotection since 4000BC. Only in the last century, evidence-based sunscreens have existed. The first ultraviolet B filters were produced in 1928, its evidence of efficacy and safety discovered in 1956 and development of sun protection factor in 1974. Similarly, sunscreen containing ultraviolet A filters was released in 1980 and the ultraviolet A star rating system developed in 1992. Regulatory bodies for sunscreen were introduced in the 1970s and have sought to review the safety and efficacy of ingredients. With the rising number of researches on the effects of visible light on hyperpigmentation over the past decade, the need for photoprotection beyond ultraviolet has been increasing. Conclusion To provide consumers with evidence-based sunscreen, challenges remain in acquiring further evidence, regulation, and rating systems.

Chronic actinic dermatitis (CAD) is a common debilitating photodermatosis. Patients often have to completely avoid outdoor activities, which severely impacts their quality of life. Phototherapy is effective for CAD and seems to increase patients' tolerance towards sunlight and consequently decrease the extent of disease. Unfortunately, the slower onset and time-consuming nature of phototherapy limits the clinical application. Considering the effectiveness and time-saving nature of ultraviolet (UV)-A rush hardening in solar urticaria, we performed a pilot study to determine whether UV-A rush hardening is effective in CAD. Six patients with CAD were exposed to multiple sessions of UV-A for 4-5 days at 1-h intervals/day. Subsequently, maintenance UV-A exposure was performed at 1-2-week intervals. Phototesting at baseline showed that three patients were sensitive to both UV-A and -B, and the other three patients only showed UV-A sensitivity. All of the patients responded well to UV-A rush hardening and four (67%) maintained a good remission status after 1 year. The results of this pilot study suggest that UV-A rush hardening phototherapy is effective and well tolerated in the treatment of CAD, while future larger prospective studies using objective scores of disease activity and quality of life are needed.

Background Phototherapy has been a first-line treatment for early-stage mycosis fungoides (MF) since 1976. Oral 8-methoxypsoralen plus ultraviolet A (oral PUVA) and narrow-band ultraviolet B (NB-UVB) are favorable modalities owing to their availability. In previous studies, phototherapy was conducted thrice per week initially, which is not feasible for many patients. Objectives To evaluate the initial clinical responses and time to relapse in patients with early-stage MF treated with oral PUVA and NB-UVB at a twice-weekly regimen. Methods We reviewed the records of patients with biopsy-proven MF who received oral PUVA or NB-UVB in 2002-2014. Demographic data, staging, response to initial course of phototherapy, and initial relapse-free interval were collected. Results Among 70 patients, 14 (20%) and 56 (80%) were treated with oral PUVA and NB-UVB, respectively. The majority had early-stage MF (IA, 22.9%, IB, 57.1%, and IIA, 4.3%). Oral PUVA led to a complete response (CR) in 2 (14.3%) patients and partial response (PR) in 7 (50%) patients; 17 (30.4%) and 25 (44.6%) patients, respectively, achieved CR and PR with NB-UVB. The number of treatments was similar in both groups. The cumulative dose was 520.7 J/cm2 for PUVA and 41.6 J/cm2 for NB-UVB. There was no initial relapse in the 2 (100%) patients and in 10 (58.8%) patients treated with oral PUVA and NB-UVB at 18 months and 9.14 months of follow-up, respectively. Conclusion Patients with early-stage MF can achieve clinical response with oral PUVA and NB-UVB, with a twice per week regimen. The initial relapse-free interval was longer than 1 year.

The COVID-19 pandemic has sparked a demand for safe and highly effective decontamination techniques for both personal protective equipment (PPE) and hospital and operating rooms. The gradual lifting of lockdown restrictions warrants the expansion of these measures into the outpatient arena. Ultraviolet C (UVC) radiation has well-known germicidal properties and is among the most frequently reported decontamination techniques used today. However, there is evidence that wavelengths beyond the traditional 254 nm UVC - namely far UVC (222 nm), ultraviolet B, ultraviolet A, visible light, and infrared radiation - have germicidal properties as well. This review will cover current literature regarding the germicidal effects of wavelengths ranging from UVC through the infrared waveband with an emphasis on their activity against viruses, and their potential applicability in the healthcare setting for general decontamination during an infectious outbreak.

Background: Keratoconus is a frequent, familiar, bilateral, non inflammatory, and gradually progressive corneal ectasia, which leads to corneal protrusion, irregular astigmatism, and decrease vision. Currently, the corneal cross-linking (CXL) treatment could attain vision improvement. Aim: To investigate the topographic, refractive, and clinical-out-comes after six months CXL in gradually progressing keratoconic eyes. Patients & Methods: A follow-up, randomized, controlled-trial study was used. In this study, 30eyes with progressive- keratoconus (PK) were recruited in the study. Cross-linking was done and achieved by a solution of 0.1% riboflavin mixture with 20% dextran for 15minutes before and during 30minutes time-period of ultraviolet A (UV-A) irradiation (3Mwcm2). The obtained data were analysed using IBM SPSS software. Results: Statistically significant improvements were noticed in Sim k (at 6months), Kmin (at 6months), spherical power (at 6momths), cylinder power (at 6momths), spherical equivalent [SE] (at 6months), uncorrected visual acuity (UCVA) (at 6months) and best corrected visual acuity [BCVA] (at 6months) in trial group (15patients) when compared with the controls. Conclusions: At 6months, hopeful, promising improvements were reported in Kmax, UCVA, and BCVA. So, long term studies are requested to survey the efficiency of CXL as well as the safety of the repeated procedures.

Background: Corneal ectasia is a serious vision-threatening complication of laser-assisted in-situ keratomileusis (LASIK). Objective: The aim of the work was to evaluate the efficacy and safety of ultraviolet A (UVA) irradiation crosslinking in concurrent with LASIK in myopic patient with normal cornea to avoid post LASIK ectasia. Patients and Methods: This Prospective randomized interventional study included 60 eyes of 30 consecutive patient who were scheduled for LASIK surgery, all of them were myopic with normal cornea with no pervious refractive surgery. They were candidate for Combined Topo-Guided LASIK with accelerated CXL. This was done in a private eye hospital between Jun 2018 and Jun 2019. Results: The preoperative uncorrected visual acuity (UCVA) ranged from 0.05- 0.1 with mean 0.075±0.02 and preoperative best corrected visual acuity (BCVA) ranged 0.2- 1.0 with mean 0.58±0.13 and post-operative UCVA at 6 months showed ranged 0.2-1.0 with mean 0.55±0.16, and postoperative UCVA at 1 year showed ranged 0.2-1.0 with mean 0.56±0.13,. The improvement in visual acuity from 0.075±0.02 UCVA preoperatively show statistically significant difference (P > 0.05) because we compared the results with the preoperative BCVA 0.58±0.13 postoperatively at 6 months. However, t-Paired Sample t-test; p-value < 0.05 S. Conclusion: It could be concluded that LASIK combined with a prophylactic CXL intervention appears to provide predictability as well as refractive and keratometric stability. The data reported in this study provide evidence of the safety and efficacy of this approach.

Background Narrowband ultraviolet B (NB-UVB) phototherapy has become a widely used, standard treatment modality in dermatology. The effect of 8-methoxypsoralen plus ultraviolet A on antinuclear antibody (ANA) formation has been investigated extensively, but there are very scarce data about the potential risk of NB-UVB phototherapy inducing production of ANAs. The aims of this study were evaluation of ANA status before and after NB-UVB treatment and comparison of ANA status with the healthy control group. Methods Phototherapy unit database was used to identify patients who had received whole body NB-UVB treatment. Analyses of ANA were performed twice in the study group that were before initiation of the NB-UVB phototherapy and after cessation of the therapy. Also, ANAs were screened in the control group. Results A total of 95 patients (50 males and 45 females; mean age: 43.03 ± 13.40) treated with NB-UVB radiation and 90 age- and sex-matched controls were included in the study. Thirteen patients (13.7%) were found to develop ANAs at the end of the treatment. ANA positivity was significantly more common in patients after phototherapy than in patients before phototherapy and than in the control group. None of the patients in the positive ANA group was diagnosed with any connective tissue diseases. Conclusion This study revealed that ANA positivity increased after NB-UVB phototherapy. However, it did not provide evidence for increased connective tissue disease risk. Therefore, ANA might not need to be routinely checked before treatment unless the patients have signs and symptoms indicating autoimmune diseases.

PURPOSE To assess corneal biomechanical changes after conventional corneal crosslinking (CXL), with and without oxygen enrichment. METHODS Sixty fresh porcine corneas were randomly divided into group 1 (control), group 2 (conventional CXL), and group 3 (conventional CXL in a high-oxygen environment during ultraviolet A [UVA] irradiation). After crosslinking, a 5-mm wide corneal strip was extracted using a double-bladed knife from 12 to 6'o clock. The Young's modulus of each strip was determined by stress-strain measurements. A comparison between the three groups was performed with a one-way analysis of variance. RESULTS At 4% strain, the Young's modulus of the corneas in groups 1, 2, and 3 were: 0.68±0.20 megapascal (MPa), 1.01±0.23 MPa, and 1.12±0.24 MPa, respectively. The Young's modulus values for groups 2 and 3 showed no statistical significance (P>0.05), However, both groups 2 and 3 were significantly higher than group 1 (P

Corneal collagen cross-linking (CXL) treatment can restore vision in patients suffering from keratoconus and corneal injury, by improving the mechanical properties of the cornea. The correlation between ultraviolet-A (UVA) irradiant energies of standard CXL (SCXL) and corneal visco-hyperelastic mechanical behavior remains unknown. In this study, SCXL with four different UVA irradiant energy doses (0–5.4 J/cm2) were administered as part of quantitative treatments of corneal stromal lenticules extracted from young myopic patients via small incision lenticule extraction (SMILE) corneal refractive surgery. Double-strip samples with symmetric geometries were cut simultaneously for SCXL treatment and non-treated control. First, 40 pairs of strips were loaded to failure to assess the mechanical parameters of the material. Then, another 40 pairs were tested using a special uniaxial tensile test including quasi-static loading–unloading, instantaneous loading, and stress relaxation, to determine the visco-hyperelastic mechanical behavior. Upon combining the collagen fibril crimping constitutive model with the quasi-linear viscoelastic model, it was observed that with increasing UVA energy dose, the corneal strength and hyperelastic stiffness were significantly enhanced, while the maximum stretch and viscosity of the cornea were significantly reduced. Considering the quantitative analysis of SCXL and the rehabilitation prediction of keratoconus treatment, the results clarify the biomechanical behavior of human corneal stroma in SCXL clinical surgery. Statement of Significance This study quantitatively analyzes the improvement in the biomechanical properties of young central corneal stroma, due to SCXL treatment with different energies. Furthermore, the correlation between the hyper-viscoelastic mechanical parameters and UVA irradiant energy doses of SCXL are clarified. The contribution of this study fills the knowledge gap of the CXL on corneal biomechanics. It can not only clarify this mechanism better but also assist with guiding SCXL surgery for individualized patient corneas.

Long persistent phosphors (LPPs) with ultraviolet (UV) luminescence have great potential for application in the fields of biomedicine, environmental, and catalysis. However, it is currently limited...

Melanoma is an increasingly pervasive form of malignant skin cancer. Cases of cutaneous melanoma are on the rise across ages and global populations, with incidence increasing significantly for both men and women. Accordingly, the identification of modifiable behaviors is of paramount concern. Previous reviews have focused on specific risk factors (e.g. UVR, pollution, diet, hormonal supplementation) to the near exclusion of other contributory factors. This review strives to report an inclusive range of exogenous variables linked to cutaneous melanoma incidence. In this review, we examine the various contributions of exogenous factors linked to the induction of cutaneous melanoma. Factors for consideration include but are not limited to: long-wave Ultraviolet A (UVA), short-wave Ultraviolet B (UVB), hormonal supplementation, diet, smoking, alcohol, vitamin supplementation, ionizing radiation, pollution, and chemical exposure.

Reducing healthcare-associated infections is critically important. A new hybrid lighting system technology, designed to provide both visible white light and disinfecting UV-A (λmax = 366 nm) radiation, was retrofitted into a modern hospital newborn intensive care unit. The UV-A dosing was set to levels calculated to be safe for human occupation (maximum of 10 W m−2 for 8 hours at eye level). Eight-hour exposures at 3 W m−2 on newborn intensive care unit counter surfaces were effective for suppressing selected pathogens identified by the Centers for Disease Control and Prevention as problematic for healthcare facilities. Professional staff accepted the hybrid lighting system, although its implementation in this newborn intensive care unit was not completely satisfactory. An analysis of photodegrading effects suggested that UV-A resistant equipment and furnishing may need to be installed with this technology. The present findings should form the foundation for the next generation of this lighting technology.

Persistent phosphors emitting in the ultraviolet (UV) spectral region have attracted great attention in recent years, owing to their promising potential in many advanced applications ranging from photocatalysis to phototherapy. Here, we report the development of a novel UVA emissive persistent phosphor by doping Bi3+ into a LiScGeO4 host. The LiScGeO4:Bi3+ persistent phosphor can be effectively charged using a standard 254 nm UV lamp and emits intense, long-lasting persistent luminescence peaking at 365 nm for longer than 120 h. Besides, the UVA persistent luminescence from the pre-irradiated LiScGeO4:Bi3+ phosphor can be repeatedly rejuvenated by short-time photostimulation with low-energy white, red and near-infrared (NIR) light. The long-lasting UVA afterglow, together with the photostimulated persistent luminescence (PSPL) capability, makes the LiScGeO4:Bi3+ phosphor an important element of persistent luminescence materials in the UVA spectral region. This UVA persistent phosphor is expected to find exciting applications in the fields of medical therapy and environmental research.

Long-term eye exposure to ultraviolet (UV)A can effect memory and learning ability. However, the underlying mechanism behind these effects remain unknown. In this study, we used HR-1 mice to study effects of long-term UVA eye irradiation. The eyes or dorsal skin of the mice were exposed to UVA at the dose of 110kj/m2 using an FL20SBLB-A lamp three times a week over 12 months. We measured the levels of reactive oxygen species, corticotropin-releasing hormone (CRH), urocortin 2, and CRH type 2 receptor (CRHR-2) in the brain of treated and control animals. Their memory and learning ability following exposure to UVA was analyzed by the standard water maze test. Our results showed that the levels of reactive oxygen species, CRH, urocortin 2, and CRHR-2 increased significantly following long-term UVA irradiation, and the effects were more pronounced in animals subjected to eye irradiation than those subjected to dorsal skin irradiation. Furthermore, the UVA exposure led to an increase in the levels of β-amyloid and microglia in the brain. These results indicated that UVA eye irradiation potentially mediated a decline in memory and learning ability via enhancing levels of urocortin 2, microglia, and β-amyloid in the brain.

Background: Ultraviolet-A1 phototherapy has been used to treat many inflammatory dermatoses. Aims: To determine the efficacy and safety of ultraviolet-A1 phototherapy in Asian skin. Materials and Methods: We performed a review of records of patients undergoing ultraviolet-A1 phototherapy at our dermatology unit in Singapore from January 2007 to January 2011. Their electronic medical records were reviewed and a standardized questionnaire was filled up for data collection and tabulation. Chi-square or Fisher's exact tests were used to compare the difference in response between various groups for each characteristic. P value of < 0.05 was considered statistically significant. Results: Our study comprised of 159 patients, of which 103 were patients with hand and foot eczema, 21 with atopic dermatitis, 17 with scleroderma and the remaining with miscellaneous dermatoses. Of these patients, 47.6% of patients with hand and feet eczema had good response after 10 sessions, which increased to 75% after 20 sessions and to 84.6% after 30 sessions. After 10 sessions, 47.6% of patients with atopic dermatitis had good response, which increased to 66.7% after 20 sessions. After 30 sessions, all the three remaining patients with atopic dermatitis experienced good response. For patients with scleroderma, only 11.8 and 10% had good response after 10 and 20 sessions, respectively, which increased to 40% after 30 sessions. Limitations: Limitations of our study include its retrospective design and, consequently, the lack of standardized treatment protocol, as well as subjective assessment in terms of clinical improvement. Conclusions: Ultraviolet-A1 phototherapy appears to be efficacious for the treatment of hand and foot eczema as well as atopic dermatitis. However, in patients with scleroderma, the response was partial and needed a longer duration of treatment.

Background: Exposure to sunlight, mainly UVA, leads to typical changes in the features of the skin known as photoaging. UVA irradiation induces the expression of proteases that are responsible for the degradation of the extracellular matrix proteins to results in photoaging; it also downregulates the expression of proteins that are needed for the skin structure. Since, it is known that cells in the neighborhood of irradiated cells, but not directly exposed to it, often manifest responses like their irradiated counterparts, it is important to evaluate if these bystander cells too, can contribute to photoaging. Methods and Results: UVA induced cell cycle arrest have been associated with photoaging, from flow cytometry analysis we found that there was an induction of cell cycle arrest at the G1/S phase in the UVA-bystander cells. The expression of some key photoaging marker genes likes, matrix metalloproteinases (MMP-1, MMP-3, MMP-9), cyclooxygenase-2 (COX-2), collagen1 and elastin were assessed from qRT-PCR. Upregulation of MMP-1 and COX-2, downregulation of collagen1 and elastin, along with suppression below normal expression for MMP-3 and MMP-9 was observed in the UVA-bystander A375 cells. Conclusion: Our findings for the first time suggest the contribution of UVA-bystander cells to the process of photoaging.

BACKGROUND New research has attributed increased significance to the causal link between ultraviolet A (UVA) radiation and immunosuppression and carcinogenesis. In the United States, sunscreens are labeled with only their sun protection factor (SPF) and an imprecise term "broad-spectrum protection." Sunscreen marketing and efficacy evaluations continue to be based primarily on skin redness (sunburn) or erythema. We sought to evaluate the ultraviolet (UV) protection offered by common sunscreen products on the US market using laboratory-measured UV-absorption testing and comparing with computer-modeled protection and the labeled SPF values. This approach enables an investigation of the relationship between the labeled SPF and measured UVA protection, a factor that is ignored in current regulations. METHODS Fifty-one sunscreen products for sale in the United States with SPF values from 15 to 110 and labeled as providing broad-spectrum protection were tested using a commercial laboratory. All products were evaluated using the ISO 24443:2012 method for sunscreen effectiveness. The final absorbance spectra were used for analysis of in vitro UV protection. RESULTS In vitro SPF values from laboratory-measured UV absorption and computer modeling were on average just 59 and 42 percent of the labeled SPF. The majority of products provided significantly lower UVA protection with the average unweighted UVA protection factor just 24 percent of the labeled SPF. CONCLUSION Regulations and marketplace forces promote sunscreens that reduce sunburn instead of products that provide better, more broad-spectrum UV protection. The production and use of products with broad spectrum UV protection should be incentivized, removing the emphasis on sunburn protection and ending testing on people.

This study presents a tracer technique based on the fluorescent properties of quinine to help on the visualization of shallow flows and allow a quantitative measurement of overland flow velocities. Laboratory experiments were conducted to compare the traditional dye tracer and thermal tracer techniques with this novel fluorescent (quinine) tracer by injecting a quinine solution and the other tracers into shallow flowing surface water. The leading-edge tracer velocities, estimated using videos of the experiments with the quinine tracer were compared with the velocities obtained by using thermograms and real imaging videos of the dye tracers. The results show that the quinine tracer can be used to estimate both overland and rill flow velocities, since measurements are similar to those resulting from using other commonly used tracers. The main advantage of using the quinine tracer is the higher visibility of the injected tracer under ultraviolet A (UVA) light for low luminosity conditions. In addition, smaller amounts of quinine tracer are needed than for dye tracers, which lead to smaller disturbances in the flow. It requires a simple experimental setup and is non-toxic to the environment. UIDB/04292/2020 info:eu-repo/semantics/publishedVersion

We found that ultraviolet-A (UV-A) light exposure resulted in a modest reduction in recovery of methicillin-resistant Staphylococcus aureus (MRSA), Candida auris, bacteriophage MS2, and bacteriophage Phi X174, but not Clostridioides difficile spores, on steel disk carriers. Four hours of UV-A exposure from a ceiling light fixture resulted in a significant reduction in pathogenic microorganisms recovered from in-use medical equipment. These findings suggest that UV-A could be useful as a means to provide continuous low-level decontamination of surfaces in health care facilities.

PURPOSE-To evaluate outcomes of collagen crosslinking in patients having progressive keratoconus. METHODS- A prospective study was done in eyes that underwent corneal collagen crosslinking for treatment of progressive keratoconus. This study was performed after approval from Institutional Ethics Committee and informed consent was obtained from all the patients. Data was analysed with the help of JASP0.8.3.1 and MS-Excel 2013. RESULT-The mean age was 20.94 ± 2.04 years. 21 (63.63%) were males, 12 (36.36 %) were females. The mean uncorrected visual acuity (UCVA) pre-operative and post-operative at 6 months were 0.64 ± 0.37 and 0.53 ± 0.31 (logMAR) respectively (p value 0.03). Mean spherical equivalent pre-operatively and post-operatively at 6 months were -2.85 ± 2.14 and -2.38 ± 1.70 respectively (p < 0.001). Mean keratometry (Mean K) preoperative and post-operative were 49.85 ± 4.10 Dioptres (D) and 49.22 ± 4.09 D respectively (p = 0.0007). CONCLUSION- Corneal collagen crosslinking with UV-A and riboavin is a safe and effective method for halting the deterioration of progressive keratoconus.

The current study aimed to investigate the intra-ocular pressure (IOP) and morphological variations in trabecular meshwork (TM) cells from rabbit eye followed being treated with ultraviolet A/riboflavin corneal crosslinking (CXL) onto the TM area, by which to further verify the possibility of applying TM CXL onto the treatment of glaucoma in clinics in the future. Rabbits were randomly classified into the 3 groups, such as blank control, negative control, and treated groups. Afterwards, we carried out the measurement of IOP with schiotz tonometer and morphological evaluation of the TM cells via light microscopy and transmission electron microscopy before and after CXL within 12 weeks. No statistical significance was found between blank control group and negative control group as for the interspace area of TM cells, cell density of TM cells or IOP in the current study. In comparison to blank control group, interspace area in TM cells declined on day (D) 1 after CXL, followed by a significant increase within the following follow-ups from week (W) 1 to W12, and reached a stable situation on W2. Compared to the blank control group, the cell density of TM cells declined on D1 after CXL, followed by a slight increase within the following follow-ups from W1 to W12, and reached a stable situation on W2. Meanwhile, compared with the blank control group, the IOP increased on D1 after CXL, followed by a slight decrease within the following follow-ups from W1 to W12, and reached a stable situation on W2. In conclusion, the present study revealed an important decrease on IOP and predominant enlargement in the interspace area of TM cells after CXL when in comparison to blank control group, which implies the possibility of applying CXL for the treatment of glaucoma in clinics.

Purpose Corneal collagen crosslinking has been proven to be a useful technique to slow the progression of keratoconus. With its increasing use, we are encountering rare complications. We describe a case that developed bilateral viral keratitis after corneal collagen crosslinking with riboflavin and ultraviolet A for progressive keratoconus. Case report An 18-year-old boy underwent corneal collagen crosslinking in both the eyes at the same setting for bilateral progressive keratoconus. He was discharged with a soft bandage contact lens and asked to follow up in 5 days. Seven days later, the patient returned with severe pain, redness, and photophobia for the last 2 days. The bandage contact lens was removed. There was a central corneal lesion in a branching dendritic pattern in both the eyes and the corneal sensation was reduced. Based on the findings, a clinical diagnosis of bilateral viral keratitis was made. The dendrite healed completely in 10 days with oral and topical acyclovir treatment, and the cornea had a faint scar at 1 month follow-up with best-corrected visual acuity of 6/9 in both eyes with a rigid gas permeable lens. Discussion and conclusion Ultraviolet A light could be a stimulus to trigger reactivation of latent HSV infections even in patients with no history of clinically evident herpes virus ocular infections. Early diagnosis and timely treatment can have good visual outcome. Prophylactic antiviral medication may be useful to prevent this complication in individuals with prior history of viral keratitis.

Objective The carbon, titanium, and oxygen levels on titanium implant surfaces with or without ultraviolet (UV) pretreatment were evaluated at different wavelengths through X-ray photoelectron spectroscopy (XPS). Materials and Methods This interventional experimental study was conducted on nine Dio UFII implants with hybrid sandblasted and acid-etched (SLA) surface treatments, divided equally into three groups. Control group A samples were not given UV irradiation, while groups B and C samples were given UVA (382 nm, 25 mWcm2) and UVC (260 nm, 15 mWcm2) irradiation, respectively. The atomic ratio of carbon, titanium, and oxygen was compared through XPS. Results Mean carbon-to-titanium ratio and C1 peaks considerably increased in Group A compared to those in experimental Groups B and C. The intensity of Ti2p and O1s peaks was more pronounced for group C compared to that for groups A and B. Conclusions Although the decrease in surface hydrocarbons was the same in both UV-treated groups, the peak intensity of oxygen increased in the UVC-treated group. Thus, it can be concluded that compared with UVA irradiation, UVC irradiation has the potential to induce more hydrophilicity on SLA-coated implants.

Background: Various therapeutic agents have been described for alopecia areata but none is satisfactory. The use of ultraviolet A phototherapy in phototoxic regimens has emerged lately with promisi...

Polyherbal formulation combining multiple herbs is suggested to achieve enhanced therapeutic effects and reduce toxicity. Harak herbal formula (HRF) extracts were proposed to regulate skin responses to UVR through their ability to suppress UVA-induced matrix metalloproteinase-1 (MMP-1) and pigmentation via promoting antioxidant defenses in in vitro models. Therefore, natural products targeting Nrf2 (nuclear factor erythroid 2-related factor 2)-regulated antioxidant response might represent promising anti-photoaging candidates. Hesperetin (HSP) was suggested as a putative bioactive compound of the HRF, as previously shown by its chemical profiling using the liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). In this study, we explored the anti-photoaging effects of HRF extracts and HSP on normal human dermal fibroblasts (NHDFs) and mouse skin exposed to UVA irradiation. Pretreatment of NHDFs with HRF extracts and HSP protected against UVA (8 J/cm2)-mediated cytotoxicity and reactive oxygen species (ROS) formation. The HRF and HSP pretreatment also attenuated the UVA-induced MMP-1 activity and collagen depletion concomitant with an upregulation of Nrf2 activity and its downstream genes (GST and NQO-1). Moreover, our findings provided the in vivo relevance to the in vitro anti-photoaging effects of HRF as topical application of the extracts (10, 30 and 100 mg/cm2) and HSP (0.3, 1, and 3 mg/cm2) 1 h before UVA exposure 3 times per week for 2 weeks (a total dose of 60 J/cm2) mitigated MMP-1 upregulation, collagen loss in correlation with enhanced Nrf2 nuclear accumulation and its target protein GST and NQO-1 as well as reduced 8-hydroxy-2′-deoxyguanosine (8-OHdG) in irradiated mouse skin. Thus, our findings revealed that HRF extracts and HSP attenuated UVA-induced photoaging via upregulating Nrf2, together with their abilities to reduce ROS formation and oxidative damage. Our study concluded that the HRF and its bioactive ingredient HSP may represent potential candidates for preventing UVA-induced photoaging via restoration of redox balance.

Past decades demonstrate an increasing interest in herbal remedies in the public eye, with as many as 80% of people worldwide using these remedies as healthcare products, including those for skin health. Sea buckthorn and its derived products (oil, alcoholic extracts), rich in flavonoids and essential fatty acids, are among these healthcare products. Specifically, sea buckthorn and its derivatives are reported to have antioxidant and antitumor activity in dysplastic skin cells. On the other hand, evidence suggests that the alteration of lipid metabolism is related to increased malignant behavior. Given the paradoxical involvement of lipids in health and disease, we investigated how sea-buckthorn seed oil, rich in long-chain fatty acids, modifies the proliferation of normal and dysplastic skin cells in basal conditions, as well as under ultraviolet A (UVA) radiation. Using real-time analysis of normal and dysplastic human keratinocytes, we showed that sea-buckthorn seed oil stimulated the proliferation of dysplastic cells, while it also impaired the ability of both normal and dysplastic cells to migrate over a denuded area. Furthermore, UVA exposure increased the expression of CD36/SR-B2, a long-chain fatty acid translocator that is related to the metastatic behavior of tumor cells.

Peyronie and Dupuytren are pathologies characterized by the appearance of localized fibrotic lesions in an organ. These disorders originate from an excessive production of collagen in the tissue provoking dysfunction and functional limitations to the patients. Local administration of collagenase is the most used treatment for these fibrotic-type diseases, but a high lability of the enzyme limits its therapeutic efficacy. Herein, we present a novel methodology for the preparation of collagenase nanocapsules without affecting its enzymatic activity and capable of releasing the enzyme in response to an ultraviolet A (UVA) light stimulus. Polymeric coating around collagenase was formed by free-radical polymerization of acrylamide-type monomers. Their degradation capacity under UVA irradiation was provided by incorporating a novel photocleavable acrylamide-type crosslinker within the polymeric framework. This property allowed collagenase release to be triggered in a controlled manner by employing an easily focused stimulus. Additionally, UVA irradiation presents considerable benefits by itself due to its capacity to induce collagenase production in situ. An expected synergistic effect of collagenase nanocapsules in conjunction with UVA effect may present a promising treatment for these fibrotic diseases.

Purpose: To ascertain the influence of intraocular pressure (IOP) on corneal optical coherence tomography (OCT) speckle in untreated and ultraviolet A–riboflavin induced corneal collagen crosslinked rabbit eyes. Methods: Left corneas of eight rabbits were de-epithelialized and crosslinked by applying riboflavin and 30-minute ultraviolet A light exposure. After enucleation (6 months after treatment), each eyeball (treated and untreated) was mounted in a measurement setup, in which IOP was increased from 15 to 45 mm Hg in steps of 5 mm Hg. At each IOP value, single B-scans of the central cornea were acquired three times with the spectral-domain OCT Copernicus-HR. Then, three regions of interest, including the anterior, posterior, and entire corneal stroma, were automatically extracted. Five different probability distributions were used as a model for the corneal speckle and the one with the best goodness of fit was chosen for further analysis. Results: The generalized gamma distribution achieved the best goodness of fit and its scale (a) and shape (v) parameters statistically significantly changed with increasing IOP in the three regions of analysis (two-way repeated measures analysis of variance, all P

Background: Ultraviolet (UV)-A therapy is a simple, inexpensive, and effective modality for wound healing, with tremendous potential to improve healing and reduce clinical infections in a number of clinical settings. To date, application of UV-A relies on bulky and hard-to-dose lamps that provide inconsistent therapy, thus making it difficult to apply therapy that is appropriate for the patient. Methods: This study was designed to test the effectiveness of a novel wound therapy device that combines UV-A with traditional negative-pressure wound therapy (NPWT) to promote wound healing. Furthermore, we tested the ability of fiberoptic UV-A delivery to inhibit bacterial proliferation. Finally, we assayed the level of DNA damage that results from UV-A as compared to established UV-C therapies. Wound healing studies were performed in a porcine model using an articulated therapy arm that allows for continued therapy administration over an extended time course. Negative-pressure wound therapy was administered alone or with UV-A fiberoptic therapy for 2 weeks. Dressings were changed twice a week, at which time wound area was assessed. Results: Data demonstrate that UV-A with NPWT treatment of wounds results in greater healing than NPWT alone. Using the same therapy device, we demonstrate that exposure of Staphylococcus aureus and Pseudomonas aeruginosa to fiberoptic UV-A results in decreased colony area and number of both bacterial strains. Finally, we show that UV-A induces minimal DNA damage in human fibroblasts and no more DNA damage in wound tissue as compare to intact skin. Conclusions: These data demonstrate that UV-A can decrease bacterial proliferation and promote wound healing when coupled with NPWT.

BackgroundPromising preclinical experiments show that, under specific and monitored conditions, ultraviolet-A (UVA) exposure reduces certain bacteria, fungi, and viruses including coronavirus-229E without harming mammalian columnar epithelial cells. We aimed to evaluate the safety and effects of UVA therapy administered by a novel device via endotracheal tube in critically ill subjects with SARS-CoV-2 infection.MethodsFive newly intubated mechanically ventilated adults with SARS-CoV-2 infection, with an endotracheal tube size 7.5mm or greater, were treated with UVA for 20 minutes daily for 5 days, and followed for 30 days.ResultsFive subjects were enrolled (mean age 56.6yrs, 3 male). At baseline, all subjects scored 9/10 on the WHO clinical severity scale (10=death) with predicted mortality ranging from 21 to 95%. Average log changes in endotracheal viral load from baseline to day 5 and day 6 were -2.41 (range -1.16 to -4.54; Friedman P=0.002) and -3.20 (range -1.20 to -6.77; Friedman PConclusionIn this first-in-human study, endotracheal UVA therapy under specific and monitored settings, was safe with a significant reduction in respiratory SARS-CoV-2 viral burden over the treatment period.Trial RegistrationClinicalTrials.gov #NCT04572399.Key MessagesWhat is the key question?Can endotracheal narrow-band UVA therapy be a safe and effective treatment for severe SARS-CoV-2 infection?What is the bottom line?Under specific and monitored settings, endotracheal UVA light therapy may be an effective treatment for SARS-CoV-2 infection. Endotracheal UVA light therapy appears to be well tolerated in critically ill patients with SARS-CoV-2 infection.Why read on?This is the fist-in-human trial of internal UVA therapy using a alternative novel approach to combat COVID-19.

In vivo phototoxicity testing is important for predicting drug-induced phototoxicity in humans. Currently, there is no internationally validated in vivo test method for the photosafety evaluation of pharmaceuticals. In this study, we evaluated the phototoxicity of systemically administered drugs using SD rats. We first determined the appropriate ultraviolet A (UVA) dose using 8-methoxypsoralen, a well-known phototoxic drug. Compared to lower and higher UVA doses, we found that a UVA dose of 10 J/cm(2) allowed for the detection of phototoxic responses in both a dose- and time-dependent manner. We next performed a phototoxicity study using seven pharmaceutical drugs which included known phototoxic and non-phototoxic drugs using a UVA dose of 10 J/cm(2). In order to improve the accuracy of our assessment, we evaluated both gross skin findings as well as histopathological findings. Using gross skin findings alone resulted in an accuracy of 85.7% which could be increased to 100% accuracy when the gross skin findings were combined with histopathological findings. This study suggests that the inclusion of histopathological findings increases the accuracy of the phototoxicity evaluation of systemically administered drugs in SD rats. In conclusion, we found that for studying drug-induced phytotoxicity, a 10 J/cm(2) UVA dose serves as the optimal radiation dose, and that the inclusion of histopathological findings increases the accuracy of the phototoxicity evaluation of the drugs.

BackgroundCollagen cross-links contribute to the mechanical resilience of the intervertebral disc (IVD). UVA-light-activated riboflavin-induced collagen crosslinking (UVA-CXL) is a well-established and effective ophthalmological intervention that increases the mechanical rigidity of the collagen-rich corneal matrix in Keratoconus. This study explores the feasibility, safety and efficacy of translating this intervention in reinforcing the IVD.MethodsAnnulus fibrosus (AF) cells were isolated from bovine IVDs and treated with different combinations of riboflavin (RF) concentrations (0.05-8 mM) and UVA light intensities (0.3-4 mW/cm2). Metabolic activity (resazurin assay), cell viability (TUNEL assay), and gene expression of apoptosis regulators C-FOS and PT5 were assessed immediately and 24 hours after treatment. Biomechanical effects of UVA-CXL on IVDs were measured by indentation analysis of changes in the instantaneous modulus and by peel-force delamination strength analysis of the AF prior and after treatment.ResultsDifferent intensities of UVA did not impair the metabolic activity of AF cells. However, RF affected metabolic activity (p < 0.001). PT53 expression was similar in all RF conditions tested while C-FOS expression decreased 24 hours after treatment. Twenty-four hours after treatment, no apoptotic cells were observed in any condition tested. Biomechanical characterizations showed a significant increase in the annular peel strength of the UVA-CXL group, when compared to controls of UVA and RF alone (p < 0.05). UVA-CXL treated IVDs showed up to 152% higher (p < 0.001) instantaneous modulus values compared to the untreated control.ConclusionThis is the first study on UVA-CXL treatment of IVD. It induced significantly increased delamination strength and instantaneous modulus indentation values in intact IVD samples in a structure-function relationship. RF concentrations and UVA intensities utilized in ophthalmological clinical protocols were well tolerated by the AF cells. Our findings suggest that UVA-CXL may be a promising tool to reinforce the IVD matrix.

Psoralen plus ultraviolet A (PUVA) photochemotherapy refers to the use of psoralen and ultraviolet A (320–400 nm) radiation for treatment. This is administered either orally or topically. Both are administered 2 to 3 times weekly, with dosing dependent on skin phototype or minimal phototoxic dose. The primary indication for PUVA is psoriasis and cutaneous T-cell lymphoma, in addition to numerous other papulosquamous dermatoses, vitiligo, pruritus, and some photodermatoses. Over the last few decades, narrow-band ultraviolet B (UVB) has emerged as the standard of care and preferred method of phototherapy because of equal or superior clinical efficacy, ease of administration, and short- and long-term safety profile. Excimer laser/lamp (308 nm) and ultraviolet A (UVA)-1 are other less commonly used forms of phototherapy, primarily indicated for smaller body surface areas of less than 10% and sclerodermoid dermatoses, respectively.

Cannabidiol (CBD), a natural occurring phytocannabinoid, is used extensively in consumer products ranging from foods to shampoos, topical oils and lotions. Several studies demonstrated the anti-inflammatory and antioxidative properties of cannabidiol. Nevertheless, the role of cannabidiol use in sunscreens is largely unknown as no studies on its effect on keratinocytes or melanocytes exist. As such, we aimed to explore the effect of CBD on keratinocyte and melanocyte viability following ultraviolet B (UVB) irradiation. CBD exhibited a dose-dependent protective effect on both keratinocytes and melanocyte viability. Further, since CBD does not demonstrate absorption in the UVB spectra, we speculate that the protective effect is due to reduction in reactive oxygen species. To our knowledge, this is the first study demonstrating the protective effect of CBD on keratinocytes and melanocytes irradiated with UVB.

The right timing of animal physiology and behaviour ensures the stability of populations and ecosystems. To predict anthropogenic impacts on these timings, more insight is needed into the interplay between environment and molecular timing mechanisms. This is particularly true in marine environments. Using high-resolution, long-term daylight measurements from a habitat of the marine annelid Platynereis dumerilii, we found that temporal changes in ultraviolet A (UVA)/deep violet intensities, more than longer wavelengths, can provide annual time information, which differs from annual changes in the photoperiod. We developed experimental set-ups that resemble natural daylight illumination conditions, and automated, quantifiable behavioural tracking. Experimental reduction of UVA/deep violet light (approximately 370–430 nm) under a long photoperiod (16 h light and 8 h dark) significantly decreased locomotor activities, comparable to the decrease caused by a short photoperiod (8 h light and 16 h dark). In contrast, altering UVA/deep violet light intensities did not cause differences in locomotor levels under a short photoperiod. This modulation of locomotion by UVA/deep violet light under a long photoperiod requires c-opsin1, a UVA/deep violet sensor employing Gi signalling. C-opsin1 also regulates the levels of rate-limiting enzymes for monogenic amine synthesis and of several neurohormones, including pigment-dispersing factor, vasotocin (vasopressin/oxytocin) and neuropeptide Y. Our analyses indicate a complex inteplay between UVA/deep violet light intensities and photoperiod as indicators of annual time. The intensity of UVA light, in addition to the photoperiod, is shown to determine seasonal change in the marine mass spawning annelid Platynereis dumerilii.