UVB Light Research Articles

Ultraviolet light induces mechanical and structural changes in full thickness human skin

While the detrimental health effects of prolonged ultraviolet (UV) irradiation on skin health have been widely accepted, the biomechanical process by which photoaging occurs and the relative effects of irradiation with different UV ranges on skin biomechanics have remained relatively unexplored. In this study, the effects of UV-induced photoageing are explored by quantifying the changes in the mechanical properties of full-thickness human skin irradiated with UVA and UVB light for incident dosages up to 1600 J/cm2. Mechanical testing of skin samples excised parallel and perpendicular to the predominant collagen fiber orientation show a rise in the fractional relative difference of elastic modulus, fracture stress, and toughness with increased UV irradiation. These changes become significant with UVA incident dosages of 1200 J/cm2 for samples excised both parallel and perpendicular to the dominant collagen fiber orientation. However, while mechanical changes occur in samples aligned with the collagen orientation at UVB dosages of 1200 J/cm2, statistical differences in samples perpendicular to the collagen orientation emerge only for UVB dosages of 1600 J/cm2. No notable or consistent trend is observed for the fracture strain. Analyses of toughness changes with maximum absorbed dosage reveals that no one UV range is more impactful in inducing mechanical property changes, but rather these changes scale with maximum absorbed energy. Evaluation of the structural characteristics of collagen further reveals an increase in collagen fiber bundle density with UV irradiation, but not collagen tortuosity, potentially linking mechanical changes to altered microstructure.

Foxp3 exon 2 regulates keratinocyte-specific IgE and basophil extracellular traps in cutaneous autoimmune photosensitivity.

Abstract Ultraviolet B (UVB) light is a common environmental trigger that can induce flares in several autoimmune diseases, but the mechanisms that mediate UVB-induced photosensitivity remain poorly understood. We used mice which express an autoimmune-driving isoform of Foxp3, called FoxP3 ΔE2mice, to develop a model autoimmune cutaneous photosensitivity. In the steady-state, FoxP3 ΔE2mice have high serum titers of IgE that target skin-associated autoantigens, and increased numbers of IL4-producing T follicular helper cells that target skin-associated proteins (Keratin 14) in the absence of overt immune challenge. After skin exposure to UVB light, FoxP3 ΔE2mice had further elevated IgE, worsened skin inflammation, and increased IgE complex deposition that localized to the challenge site. IgE production in UVB-challenged mice correlated with increased frequencies of germinal center (GC) B cells, elevated percentages of IL-4 +T follicular helper cells, and numbers of basophils with high surface expression of IgE in the draining lymph nodes of UVB-challenged skin. We also observed a significant increase in IgE accumulation, increased numbers of Tug8 +basophil extracellular traps in UVB-challenged skin and increased frequencies of activated plasmacytoid dendritic cells (CD80 +CD86 +) in the skin and skin-draining lymph nodes of FoxP3 ΔE2mice when compared to wild-type littermates. Collectively, we found that T follicular regulatory cells in FoxP3 ΔE2mice fail to maintain self-tolerance in the GC, resulting in increased production of skin reactive IgE and worsened skin inflammation driven by basophil extracellular trap accumulation in UVB-damaged skin. Supported by grants from the NIH (F32 AI154787, R01 AI136475, R21 AI169418, and R21 AI152444)

Cellulose nanofiber-based pH indicator integrated with resazurin-modified carbon dots for real-time monitoring of food freshness

Modified carbon dots with resazurin (R-CD) were prepared using a hydrothermal method to fabricate a CNF-based pH-responsive indicator for real-time food freshness monitoring. FE-SEM and FTIR results confirmed that the R-CD was uniformly distributed in the CNF matrix. The thermal stability of the CNF/R-CD indicator film was increased, and the water contact angle of the film was slightly lower than that of the neat CNF film. The CNF/R-CD film showed excellent UV-barrier properties, with ∼98.3% and 87.7% blocking the UV-B and UV-A light. The indicator film showed excellent color stability even after 2 months of storage at 25 °C and responded rapidly to alkaline pH and NH3 through a color change from yellow to brownish-red. The CNF/R-CD indicator films exhibited distinct color changes during shrimp packaging depending on pH and TVB-N concentration. Therefore, the CNF/R-CD indicator can be used as a promising pH-sensitive color-changing intelligent packaging application for freshness monitoring.

Photocatalytic Degradation of Methylene Blue Using N-Doped ZnO/Carbon Dot (N-ZnO/CD) Nanocomposites Derived from Organic Soybean.

This study reports on successful synthesis of carbon dots (CDs), nitrogen-doped zinc oxide (N-ZnO), and N-ZnO/CD nanocomposites as photocatalysts for degradation of methylene blue. The first part was the synthesis of CDs utilizing a precursor from soybean and ethylenediamine as a dopant by a hydrothermal method. The second part was the synthesis of N-ZnO with urea as the nitrogen dopant carried out by a calcination method in a furnace at 500 °C for 2 h in an N2 atmosphere (5 °C min-1). The third part was the synthesis of N-ZnO/CD nanocomposites. The characteristics of CDs, N-ZnO, and N-ZnO/CD nanocomposites were analyzed through Fourier transform infrared (FTIR), UV-vis absorbance, photoluminescence (PL), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), thermal gravimetry analysis (TGA), field-emission scanning electron microscopy energy-dispersive spectroscopy (FESEM EDS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analysis. Based on the HR-TEM analysis, the CDs had a spherical shape with an average particle size of 4.249 nm. Meanwhile, based on the XRD and HR-TEM characterization, the N-ZnO and N-ZnO/CD nanocomposites have wurtzite hexagonal structures. The materials of N-ZnO and N-ZnO/CD show increased adsorption in the visible light region and low energy gap E g. The E g values of N-ZnO and N-ZnO/CDs were found to be 2.95 and 2.81 eV, respectively, whereas the surface area (S BET) values 3.827 m2 g-1 (N-ZnO) and 3.757 m2 g-1(N-ZnO/CDs) belonged to the microporous structure. In the last part, the photocatalysts of CDs, N-ZnO, and N-ZnO/CD nanocomposites were used for degradation of MB (10 ppm) under UV-B light irradiation pH = 7.04 (neutral) for 60 min at room temperature. The N-ZnO/CD nanocomposites showed a photodegradation efficiency of 83.4% with a kinetic rate of 0.0299 min-1 higher than N-ZnO and CDs. The XRD analysis and FESEM EDS of the N-ZnO/CDs before and after three cycles confirm the stability of the photocatalyst with an MB degradation of 58.2%. These results have clearly shown that the N-ZnO/CD nanocomposites could be used as an ideal photocatalytic material for the decolorization of organic compounds in wastewater.

Bixin, a performing natural antioxidant in active food packaging for the protection of oxidation sensitive food

Natural antioxidants used in active packaging are an effective food technology to preserve oxygen sensitive foodstuff. Bixin, a carotenoid with coloring and antioxidant properties extracted from annatto seeds, was included in plasticized or not poly(lactide) (PLA) films using melt processing at 1 g/kg to increase the light barrier of the packaging and to deliver antioxidants to the food matrix. The melt processing caused degradation of bixin to more than 75%. The degradation products were analyzed using liquid chromatography coupled to mass spectrometry. The principal degradation process was cis/trans-isomerization. Despite this important structural change satisfactory barrier properties to UVA and UVB light were conserved in PLA films. Analysis of the protective performance of the packaging materials showed that the shelf-life of the vitamin riboflavin could be increased, and the augmentation of the peroxide values in sunflower oil slowed down. Bixin is therefore a very promising natural antioxidant, which could be used in packaging materials requiring melt processing.

Exploring the metabolic and physiological roles of HQT in S. lycopersicum by gene editing.

The most abundant phenolic compound in Solanaceous plants is chlorogenic acid (CGA), which possesses protective properties such as antimicrobial and antioxidant activities. These properties are particularly relevant when plants are under adverse conditions, such as pathogen attack, excess light, or extreme temperatures that cause oxidative stress. Additionally, CGA has been shown to absorb UV-B light. In tomato and potato, CGA is mainly produced through the HQT pathway mediated by the enzyme hydroxycinnamoyl-CoA:quinate hydroxycinnamoyl transferase. However, the absence of natural or induced mutants of this gene has made it unclear whether other pathways contribute to CGA production and accumulation. To address this question, we used CRISPR technology to generate multiple knock-out mutant lines in the tomato HQT gene. The resulting slhqt plants did not accumulate CGA or other caffeoylquinic acids (CQAs) in various parts of the plant, indicating that CQA biosynthesis depends almost entirely on the HQT pathway in tomato and, likely, other Solanaceous crops. We also found that the lack of CGA in slhqt plants led to higher levels of hydroxycinnamoyl-glucose and flavonoids compared to wild-type plants. Gene expression analysis revealed that this metabolic reorganization was partly due to flux redirection, but also involved modulation of important transcription factor genes that regulate secondary metabolism and sense environmental conditions. Finally, we investigated the physiological role of CGA in tomato and found that it accumulates in the upper epidermis where it acts as a protector against UV-B irradiation.

Nb-UVB and PUVA therapy in treating early stages of Mycosis Fungoides: A single-center cross-sectional study.

Mycosis fungoides (MF) and Sezary Syndrome are the most common forms of cutaneous T-cell lymphoma. Early-stage MF is known to have an indolent behavior, and the EORTC guidelines recommend treating patients with skin-directed therapies, such as phototherapy, instead of systemic therapies. Phototherapy is a popular therapeutic option, with two commonly used light sources-PUVA and narrow band-nb UVB. PUVA is less commonly used due to its potential carcinogenic role, but it has systemic effects, while nb-UVB has mostly skin-limited effects. There is ongoing debate regarding the role of UVB light, and in 2021, the Cutaneous Lymphoma Italian Study Group reached a consensus on technical schedules for NB-UVB and PUVA for MF. This study aims to analyze and compare the efficacy of the two phototherapy options in treating early-MF patients. The study included patients diagnosed with stage IA/B MF in the last 10 years, who had at least 12 months of follow-up data and a minimum of 24 phototherapy sessions (PUVA or nb UVB) and treated with topical steroids apart from phototherapy. Results showed that the two phototherapy options were similarly effective in treating early MF, with no significant differences in clinical response, although PUVA was associated with more adverse effects. The study provides valuable insights into the use of phototherapy in early MF, and the results can be used to guide treatment decisions and improve patient outcomes.

Minimal effects of ultraviolet light supplementation on egg production, egg and bone quality, and health during early lay of laying hens.

Chicken vision is sensitive to ultraviolet (UV) light containing the UVA spectrum, while UVB plays a key role in the endogenous production of vitamin D3. However, commercially available light sources are typically deficient in the UV spectrum and thus may not adequately fulfill the lighting requirements of indoor-housed laying hens. We hypothesized that supplementary UVB light may improve egg production and egg quality, and bone health during early lay relative to UVA supplementation or standard control lighting. To investigate the effects of UV light supplementation, an experiment was conducted on 252 ISA Brown hens during 16 to 27 weeks of age. Birds were housed in eighteen pens (14 hens/pen) under three different light treatment groups each with six replications: (i) UVO: standard control lighting with LED white light, (ii) UVA: control lighting plus supplemental daylight with an avian bulb, and (iii) UVA/B: control lighting plus a supplemental full spectrum reptile bulb containing both UVA and UVB wavelengths. Hen-day egg production and egg quality, blood parameters including plasma Ca and P, and serum 25(OH)D3, and hen body weight and external health scoring were measured at different age points; while bone quality was assessed at the end of the experiment at 27 weeks. Data were analyzed in JMP® 16.0 using general linear mixed models with α level set at 0.05. Results showed that UVA and UVA/B supplemented birds reached sexual maturity (50% production) 3 and 1 day earlier, respectively, than control birds. There was a trend for UV lights to increase hen-day egg production (P=0.06). Among egg quality traits, only eggshell reflectivity and yolk index were affected by UV lights (P=0.02 and 0.01, respectively); however, most of the egg quality traits changed over age (all P<0.01). Post-hoc tests showed higher serum 25(OH)D3 in the UVA/B group relative to control hens (P<0.05); but there was no treatment effect on plasma Ca and P or on bone quality parameters (all P>0.05). A significant interaction was observed between light treatment and age for the number of comb wounds (P=0.0004), with the UV supplemented hens showing more comb wounds after 24 weeks. These results demonstrated that supplemental UVA/B light had minimal effects on egg production and egg quality, whereas, UVA/B exposure may increase vitamin D3 synthesis during the early laying period. The optimum duration of exposure and level of intensity needs to be determined to ensure these benefits.

Prevention and Repair of Ultraviolet B-Induced Skin Damage in Hairless Mice via Transdermal Delivery of Growth Factors Immobilized in a Gel-in-Oil Nanoemulsion.

Ultraviolet (UV) radiation from the sun or artificial sources is one of the primary causes of skin damage, including sunburns, tanning, erythema, and skin cancer. Among the three different types of UV rays, UVB rays have a medium wavelength that can penetrate the epidermal layer of the skin, resulting in sunburn, suntan, blistering, and melanoma in case of chronic exposure. This study aimed to evaluate the preventive and therapeutic effects of a gel-in-oil nanogel dispersion (G/O-NGD) as a transdermal delivery biomolecular carrier for skin damage caused by UVB light. The efficacy of this carrier against UVB-induced skin damage was investigated in vivo by delivering different growth factors (GFs) encapsulated in a G/O-NGD. Artificial UVB light was used to induce skin damage in nude mice, followed by the transdermal application of five GF [vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), transforming growth factor (TGF)-1, and insulin-like growth factor (IGF)-α]-immobilized G/O-NGD. Among these GFs, VEGF and bFGF promoted angiogenesis, while EGF, TGF-1, and IGF-α promoted the repair and regeneration of damaged cells. The results showed that G/O-NGD was superior to heparin-immobilized G/O-NGD in reducing UVB-induced skin damage, such as erythema, epidermal water reduction, inflammation, and dermis thickening. In addition, G/O-NGD could prevent and treat abnormal follicle proliferation caused by UVB rays and exhibited potential to repair lipid glands. Overall, our results demonstrate the potential of G/O-NGDs for the treatment of UVB-induced skin damage.

Development of novel betabaculovirus (HycuGV-Hc1) as a biopesticide (HycuGV-TR61) and its efficacy on the fall webworm, Hyphantria cunea Drury (Lepidoptera: Erebidae) larvae

BackgroundThe aim of this study was to develop an oil formulation from a local betabaculovirus. Hyphantria cunea Drury (Lepidoptera: Erebidae) granulovirus (HycuGV-Hc1) was isolated from the infected larvae to test its efficacy on the pest. The oil formulation was prepared by mixing the viral suspension with sunflower oil and some adjuvants and named HycuGV-TR61. Crude virus and the formulations were carried out on third instar H. cunea larvae using 1 × 104–8 OBs /ml concentrations and were exposed to temperatures (28, 35, and 42 °C) and UV-B light at different periods (0, 1, 3, 5 h).ResultsThe mortality rate, which was 50% at the lowest concentration (1 × 104 OB/ml), reached 99.86% at the highest concentration (1 × 108 OB/ml). LC50 values of fresh and old forms were calculated as 0.64 × 104 and 0.87 × 104 OBs/ml, respectively. Application of shelf life showed that there was non-significant change in the pathogenic activity of the formulation with time. In the experiments, it was observed that the activity decreased as the temperature and time of exposure increased. Significantly difference in larval mortality was observed when fresh and old formulations were exposed to 0, 1, 3 and 5 h to UV-B, (old: 96.7, 86, 80 and 60%; fresh: 97.1, 90, 85 and 62%, respectively).ConclusionsThe results revealed superior aspects of HycuGV-TR61, which was developed as a local viral biopesticide, its resistance to abiotic factors and its potential to be used in pest control.

Bioavailability of vitamin D biofortified pork meat: results of an acute human crossover study in healthy adults

Vitamin D intakes are concerningly low. Food-based strategies are urgently warranted to increase vitamin D intakes and subsequently improve 25-hydroxyvitamin D (25(OH)D) concentrations. This acute randomised three-way crossover study investigated the efficacy of vitamin D biofortified pork derived from pigs exposed to UVB light to increase serum 25(OH)D3 concentrations, compared to a dose-matched vitamin D3 supplement and control pork in adults (n = 14). Blood samples were obtained at baseline and then 1.5, 3, 6, 9 and 24 h postprandially. There was a significant effect of time (p < 0.01) and a significant treatment*time interaction (p < 0.05). UV pork and supplement significantly increased within-group serum 25(OH)D3 concentrations over timepoints (p < 0.05) (max. change 0.9 nmol/L (2.2%) UV pork, 1.5 nmol/L (3.5%) supplement, 0.7 nmol/L (1.9%) control). Vitamin D biofortified pork modestly increased 25(OH)D3 concentrations and produced a similar response pattern as a dose-matched vitamin D supplement, but biofortification protocols should be further optimised to ensure differentiation from standard pork.

Administration of Sugar Apple Leaf Extract Cream (Annona squamosa L.) Increased Superoxide Dismutase (SOD) Activity and Decreased Skin Matrix Metalloproteinase-1 (MMP-1) Activity in Male White Rats (Rattus norvegicus) Wistar Strain Exposed to Ultraviolet B Light

Background: Ultraviolet B rays from sunlight causes increased levels of matrix metalloproteinase-1 (MMP-1). Superoxide dismutase (SOD) also will decrease to counteract these free radicals. Sugar apple (Annona squamosa L.) leaf extract showed significant antioxidant and anti-collagenase activity in vitro. Methods: This is a posttest only control group design study. Thirty male white Wistar rats (Rattus norvegicus), 12 weeks old, 150-200 grams were divided into five groups, 1 group without UVB exposure and without cream, and 4 groups was exposed to UVB 3 times a week and by giving cream 2 times a day for 2 weeks, 20 minutes before exposure and 4 hours after exposure. Rats were fixated in a box. The UVB dose was 65 mJ/cm2 for 65 seconds, with total 390 mJ/cm2. Skin samples were tested using ELISA method. Results: Negative control (P1) compared to Sugar apple (Annona squamosa L.) leaf extract cream 1%. (P2), 3% (P3), and 5% (P4) concentration for SOD levels were 2.3015 ± 0.32501 vs. 2.7817 ± 0.26899 vs. 4.7752 ± 0.65218 vs. 6.0890 ± 0.63946, respectively and for MMP-1 levels were 3.0753 ± 0.51113 vs. 2.3037 ± 0.15556 vs. 1.5840 ± 0.25473 vs. 0.9198 ± 0.16604, p &lt; 0.001), respectively. Conclusion: Sugar apple (Annona squamosa L.) leaf extract cream 3% and 5% can increase SOD levels and 1%, 3%, and 5% can reduce MMP-1 levels in the skin of male Wistar rats (Rattus norvegicus) exposed to UVB light. Concentration 3% is the most effective. Keywords: sugar apple leaf extract, SOD, MMP-1, ultraviolet B rays

Green means go: Green light promotes hypocotyl elongation via brassinosteroid signaling.

Although many studies have elucidated the mechanisms by which different wavelengths of light (blue, red, far-red, or ultraviolet-B [UV-B]) regulate plant development, whether and how green light regulates plant development remains largely unknown. Previous studies reported that green light participates in regulating growth and development in land plants, but these studies have reported conflicting results, likely due to technical problems. For example, commercial green light-emitting diode light sources emit a little blue or red light. Here, using a pure green light source, we determined that unlike blue, red, far-red, or UV-B light, which inhibits hypocotyl elongation, green light promotes hypocotyl elongation in Arabidopsis thaliana and several other plants during the first 2-3 d after planting. Phytochromes, cryptochromes, and other known photoreceptors do not mediate green-light-promoted hypocotyl elongation, but the brassinosteroid (BR) signaling pathway is involved in this process. Green light promotes the DNA binding activity of BRI1-EMS-SUPPRESSOR 1 (BES1), a master transcription factor of the BR pathway, thus regulating gene transcription to promote hypocotyl elongation. Our results indicate that pure green light promotes elongation via BR signaling and acts as a shade signal to enable plants to adapt their development to a green-light-dominant environment under a canopy.

Insight into the effect of natural organic matter on the photooxidation of arsenite induced by colloidal ferric hydroxides in water

Surface complexation of arsenite (As(III)) on colloidal ferric hydroxide (CFH) plays an important role not only in the adsorptive immobilization of As(III) but also in the subsequent oxidation of As(III) to arsenate (As(V)) through light-induced ligand-to-metal charge transfer (LMCT) in water at near-neutral pH. However, the effects of natural organic matter (NOM), especially humic substances (HSs) and low molecular weight carboxylic acids (CAs), on the photochemistry of the CFH-As(III) system have not been sufficiently understood. In this work, the inhibition of photooxidation of As(III) in terms of the observed apparent rate constant (kobs) by six HSs (below 16 mg L−1) and seven CAs (below 2.5 mM) has been observed in water containing 66 μM Fe(III) and 5 μM As(III) at pH 7 under simulated solar irradiation consisting of UVA (λmax 365 nm) and UVB (λmax 313 nm) lights. Total inhibition factors (T) have been determined from the combined effect of light-screening factor (S) and competitive complexation factor (C), wherein both S and C varied with NOM concentration. S was obtained by determining the absorbance of NOM, and C was obtained by fitting modified Langmuir or Freundlich models to the amount of As(III) desorbed from CFH upon the addition of NOM. Statistical analysis between the experimental Texp and the calculated one according to Tcal = S × C showed that the Freundlich model (RMSE for HS 0.1609 and for CA 0.1771) was better than the Langmuir model and was statistically robust (QLOO2= 0.691 > 0.5). This work provided an estimation method for the effects of NOM on As(III) photooxidation in the presence of CFH as well as a deeper understanding of the transformation of arsenic species in sunlit water.

Light-Induced Flavonoid Biosynthesis in Sinopodophyllum hexandrum with High-Altitude Adaptation.

Sinopodophyllum hexandrum is a perennial alpine herb producing the anti-cancer metabolite podophyllotoxin (PPT). Although the adaptation of S. hexandrum to high altitudes has been demonstrated and the effects of temperature, precipitation, and UV-B light on plant growth and metabolite accumulation have been studied, knowledge on the role of flavonoid biosynthesis in adapting to high altitudes is limited. In this study, light intensity, amount and type of flavonoids, and differentially expressed proteins (DEPs) and genes (DEGs) at 2300 and 3300 m were analyzed by HPLC, proteomic, transcriptomic, and qRT-PCR analysis. We found that higher light intensity correlated with greater flavonoid, flavonol, and anthocyanin content as well as higher anthocyanin to total flavonoid and flavonol ratios observed at the higher altitude. Based on proteomic and transcriptomic analyses, nine DEPs and 41 DEGs were identified to be involved in flavonoid biosynthesis and light response at 3300 m. The relative expression of nine genes (PAL, CHS1, IFRL, ANS, MYB4, BHLH137, CYP6, PPO1, and ABCB19) involved in flavonoid biosynthesis and seven genes (HSP18.1, HSP70, UBC4, ERF5, ERF9, APX3, and EX2) involved in light stress were observed to be up-regulated at 3300 m compared with 2300 m. These findings indicate that light intensity may play a regulatory role in enhancing flavonoid accumulation that allows S. hexandrum to adapt to elevated-altitude coupled with high light intensity.

UVB light influence on the laccase enzyme catalytic activity in reverse micelles and in homogeneous aqueous medium.

Laccase is a versatile enzyme widely used for the oxidation of environmental contaminants and exhibits great potential in many others applications; however, it undergoes photo-degradation when irradiated with UVB light. The photo-stability of this biomolecule can be improved by immobilization in different encapsulation media and reverse micelles have been employed with this purpose. The laccase activity using syringaldazine as substrate has been studied in the absence and in the presence of reverse micelles of 0.15M of sodium 1,4-bis (2-ethylhexyl) sulfosuccinate (AOT) in isooctane at W0 ([H2O]/[AOT]) = 30, before and after irradiation of the enzyme with UVB light. The kinetic parameters, i.e., Michaelis-Menten constant (KM), catalytic constant (kCAT), and catalytic efficiency (kCAT/KM), were determined by spectroscopic measurements in the micellar system and in homogeneous aqueous medium. The distribution of the substrate in two pseudo-phases (micelle and organic solvent) was taking into account inthe kinetic parameters' determinations. The results obtained indicate that the nano-aggregate system confers a solubilization media in the water core of the micelle, both for the enzyme and the substrate, in which the catalytic function of the enzyme is preserved. On the other hand, in homogeneous aqueous medium kCAT/KM value, it is reduced by ~50% after UVB irradiation of the enzyme, while in micellar medium, less than 10% of the activity was affected. This mean that the enzyme achieves a considerably photo-protection when it is irradiated with UVB light in reverse micelles as compared with the homogeneous aqueous medium. This phenomenon can be mainly due to the confinement of the biomolecule inside the micelle. Physical properties of the nano-environment could affect photochemical reactions.

A self-powered and broadband UV PIN photodiode employing a NiOx layer and a β-Ga2O3 heterojunction

Crucial commercial and space applications require the detection of broadband ultraviolet (UV) rays spanning from UV-A to UV-C. In this study, the authors demonstrate a broadband UV photodetector employing a p-type NiOx layer and an n-type β-Ga2O3 heterostructure in PIN configuration for the first time. Simulations are conducted to optimize the doping concentration and thickness of the NiOx layer, ensuring that (a) a reasonable depletion width is maintained within the NiOx layer for UV-A and UV-B light absorption; (b) anode ohmic contacts are formed on the nondepleted NiOx film, and (c) >70% of the UV-C light is absorbed by β-Ga2O3. The optimized NiOx/β-Ga2O3 PIN photodiode exhibits good responsivity to incident light wavelengths in the UV-A, UV-B, and UV-C regions. While the NiOx layer is considered to be responsible for providing good photoresponsivity in the UV-A and UV-B regions, a highly resistive (near-intrinsic) β-Ga2O3 layer is required for the absorption of incident UV-C light. A record detectivity of >1011 cm Hz0.5 W−1 for the UV-B and UV-C regions and >1010 cm Hz0.5 W−1 for the UV-A region is observed in the NiOx/β-Ga2O3 heterostructure PIN photodiode during the self-powered operation. The results presented in this study are promising and instigate device design strategies for (ultra)wide bandgap semiconductor-based broadband UV PIN photodetectors.

Secretome Hypoxia Mesenchymal Stem Cells Inhibited Ultraviolet Radiation by Inhibiting Interleukin-6 through Nuclear Factor-Kappa Beta Pathway in Hyperpigmentation Animal Models

UVB radiation is the main factor causing hyperpigmentation. Secretome hypoxic mesenchymal stem cells (S-HMSCs) contain bioactive soluble molecules such as growth factors and anti-inflammatory cytokines that can prevent melanin synthesis and induce collagen formation. However, the role of S-HMSCSs on IL-6, p50, and p65 gene expression in hyperpigmentation is still unclear. This study aimed to determine the effect of administration of S-HMSCSs gel on the expression of IL-6, p50, and p65 in a hyperpigmented rat skin model induced by UVB light exposure. Twenty-five male Wistar rats of hyperpigmented were created as an animal model under exposed to UVB 6 times in 14 days at 302 nm with a MED of 390 mJ/cm2. The animal was randomly assigned into five groups consisting of two treatment groups (treated by S-HMSCs at a 100µL as T1 and 200µL as T2 on bases gel) for 14 days, control groups (UVB-irradiation), sham (negative control), and base gel groups. On the 14th day, IL-6, p50, and p65 were terminated and analyzed using qRT-PCR. Statistical analysis will perform using one way ANOVA followed with post hoc LSD test. Analysis of IL-6 (8.59± 3.32), p50 (4.35±2.27), and p65 (4.09±1.82) gene expression in the treatment group decreased along with the increase in the concentration of S-MSCs compared to the control group. In conclusion, the administration of S-HMSCs gel is expected to affect the speed of decreasing the hyperpigmentation process significantly.

Programming Photodegradability into Vinylic Polymers via Radical Ring‐Opening Polymerization

AbstractIncorporation of photolabile moieties into the polymer backbone holds promise to remotely‐control polymer degradation. However, suitable synthetic avenues are limited, especially for radical polymerizations. Here we report a strategy to program photodegradability into vinylic polymers by exploiting the wavelength selectivity of photocycloadditions for radical ring‐opening polymerization (rROP). Irradiation of coumarin terminated allylic sulfides with UVA light initiated intramolecular [2+2] photocycloaddition producing cyclic macromonomers. Subsequent RAFT‐mediated rROP with methyl acrylate yielded copolymers that inherited the photoreactivity of the cyclic parent monomer. Irradiation with UVB initiated efficient photocycloreversion of the coumarin dimers, causing polymer degradation within minutes under UVB light or days under sunlight exposure. Our synthetic strategy may pave the way to insert photolabile linkages into vinylic polymers, tuning degradation for specific wavelengths.

Programming Photodegradability into Vinylic Polymers via Radical Ring-Opening Polymerization.

Incorporation of photolabile moieties into the polymer backbone holds promise to remotely-control polymer degradation. However, suitable synthetic avenues are limited, especially for radical polymerizations. Here we report a strategy to program photodegradability into vinylic polymers by exploiting the wavelength selectivity of photocycloadditions for radical ring-opening polymerization (rROP). Irradiation of coumarin terminated allylic sulfides with UVA light initiated intramolecular [2+2] photocycloaddition producing cyclic macromonomers. Subsequent RAFT-mediated rROP with methyl acrylate yielded copolymers that inherited the photoreactivity of the cyclic parent monomer. Irradiation with UVB initiated efficient photocycloreversion of the coumarin dimers, causing polymer degradation within minutes under UVB light or days under sunlight exposure. Our synthetic strategy may pave the way to insert photolabile linkages into vinylic polymers, tuning degradation for specific wavelengths.