UVA Light Research Articles

A nanotechnology‐based solution for epi‐on corneal cross‐linking

Keratoconus (KC) is a bilateral progressive corneal ectasia resulting in irregular astigmatism and loss of visual function, in youth and children. Corneal cross‐linking (CXL) is the standard treatment to halt the progression of KC. The conventional protocol consists of removal of the corneal epithelium (epi‐off), followed by soaking of riboflavin and then irradiation with UVA light, leading to stiffening of the cornea. However, postoperative ocular adverse events related to epithelial removal, such as infectious keratitis and delayed visual recovery, have been described. Some alternative methodologies have been tested but pain, no control on corneal permeability, and high investment for set‐up acquisition are drawbacks. Accordingly, the treatment of KC is at an extremely exciting stage, and research on delivering riboflavin into the cornea without removing the epithelium is underway.To address this clinical unmet need, we developed an advanced solution consisting of nanoparticle‐modified commercial soft contact lenses. Safety conditions were determined using ex vivo porcine eyes. The efficacy of our solution on corneal epithelial permeability to riboflavin was tested using in vivo rat eyes. Our nanotechnology‐based solution allows high spatial and temporal precision control of epithelial permeability to riboflavin. We aim to validate this innovative strategy as an epithelium‐on (epi‐on) protocol for the effective treatment of KC, with obvious advantages in terms of safety, patient comfort, and recovery time. Furthermore, our strategy is compatible with current equipment and riboflavin solutions, allowing to capitalize clinicians' expertise and the resources already existing in private clinics and public health services.This project was financially supported by Foundation for Science and Technology (FCT, Portugal): Exploratory Research Project EXPL/BIA‐BQM/0042/2021, Strategic Projects UIDB/04539/2020, UIDP/04539/2020, and UID/NEU/04539/2019; and by COMPETE‐FEDER (POCI‐01‐0145‐FEDER‐007440).

Photo- and electro-chemical strategies for the activations of strong chemical bonds.

The employment of light and/or electricity - alternatively to conventional thermal energy - unlocks new reactivity paradigms as tools for chemical substrate activations. This leads to the development of new synthetic reactions and a vast expansion of chemical spaces. This review summarizes recent developments in photo- and/or electrochemical activation strategies for the functionalization of strong bonds - particularly carbon-heteroatom (C-X) bonds - via: (1) direct photoexcitation by high energy UV light; (2) activation via photoredox catalysis under irradiation with relatively lower energy UVA or blue light; (3) electrochemical reduction; (4) combination of photocatalysis and electrochemistry. Based on the types of the targeted C-X bonds, various transformations ranging from hydrodefunctionalization to cross-coupling are covered with detailed discussions of their reaction mechanisms.

Providing inoculum for Didymella bryoniae studies: the effect of light spectrum and storing at low temperature.

The in vitro sporulation of Didymella bryoniae is of great importance for studies that require pure inoculum and in large quantities. Thus, the objectives of this study were to identify the best condition for D. bryoniae sporulation combining different light spectra (UV-A or UV-B light, white light, and continuous dark), with distinct culture media (PDA, V8, ML, and PDAB) and, to evaluate fungus' survivability stored at -20°C over time. The fungus samples were only able to sporulate when subjected to the UV-B light treatment, regardless of the culture medium. The highest appearance of spores conidium type was observed in the PDAB medium, and the lowest production occurred in the ML medium. Reproductive structures, such as perithecia and pycnidia, were observed in all culture media. However, there was considerable variation in the amount of each structure between the different culture media. The ML and V8 media showed a greater number of perithecia and the PDA and PDAB media presented a greater proportion of pycnidia compared to perithecia. The storage duration at -20°C did not affect mycelial growth or mycelial growth rate. In conclusion, the UV-B light is essential for D. bryoniae in vitro sporulation. Moreover, the culture medium composition influences the type of fungal structure produced, as well as spores' size and quantity. Freezing at -20°C is an efficient technique that can be used to store D. bryoniae for at least five months without loss of viability.

Photo-polymerization using quantum dots for stable epoxy coatings

Flame-made titania quantum dots can initiate epoxy photo-polymerization when UVC light is applied, while remaining insensitive to UVA light, producing films that are mechanically stable.

Reusable magnetic mixture of CuFe2O4-Fe2O3 and TiO2 for photocatalytic degradation of pesticides in water.

Photocatalysis is a promising treatment method to remove pollutants from water. TiO2-P25 is a commercially available model photocatalyst, which very efficiently degrades organic pollutants under UVA light exposure. However, the collection and the recovery of TiO2-P25 from cleaned water poses significant difficulties, severely limiting its usability. To address this challenge, we have prepared a sintered mixture of TiO2-P25 nanomaterials and magnetic CuFe2O4-Fe2O3 nanocomposites. The mixture material was shown to contain spinel ferrite, hematite and maghemite structures, copper predominantly in Cu2+ and iron predominantly in Fe3+ state. The CuFe2O4-Fe2O3 and TiO2-P25 mixture demonstrated magnetic collectability from processed water and photocatalytic activity, which was evidenced through the successful photodegradation of the herbicide 2,4-D. Our findings suggest that the sintered mixture of CuFe2O4-Fe2O3 and TiO2-P25 holds a promise for improving photocatalytic water treatment, with the potential to overcome current photocatalyst recovery issues.

Optical Limiting Properties of DNA Biopolymer Doped with Natural Dyes.

The high-power lasers have important implications for present and future light-based technologies; therefore, the protection measures against their high-intensity radiation are extremely important. Currently, a great deal of interest is directed towards the development of new nonlinear optical materials for passive optical limiters, which are used to protect the human eye and sensitive optical and optoelectronic devices from laser-induced damage. Biopolymers doped with natural dyes are emerging as a new class of optical materials with interesting photosensitive properties. In this paper, the optical limiting capability of deoxyribonucleic acid bio-polymer functionalized with Turmeric natural dye has been demonstrated for the first time, to the best of our knowledge. The experimental investigation of the optical limit has been done by the Intensity-scan method in the NIR spectral domain at the important telecommunication wavelength of 1550 nm, using ultrashort laser pulses (~120 fs). Several optical properties of this natural dye are presented and discussed. The values of the optical transmittance in the linear regime, the saturation intensity of the nonlinear transmittance curves, and the coefficient of the nonlinear absorption have been determined. The influence of the DNA biopolymer and natural dye concentration on the optical limiting properties of the investigated biomaterials is reported and discussed. The photostability and thermal stability of the investigated solutions have also been evaluated by monitoring the temporal decay of the normalized absorption spectra under illumination with UVA light and heating, respectively. Our results evidence the positive influence of the DNA, which embeds Turmeric natural dye, on the optical limiting functionality itself and on the photostability and thermal stability of this novel material. The performed study reveals the potential of the investigated novel biomaterial for applications in nonlinear photonics, in particular in optical limiting.

Protective Factor Evaluation of Purslane (Portulaca grandiflora) Magenta Flower Variety Herbs Extract Cream Formula

Background: Indonesia is an equatorial country that is rich in sunlight all year. UV light is divided into three wavelength groups: UV-A (320-400nm), UV-B (280-320nm), and UV-C (100-290nm). Intracell chromophores in skin cell membranes such as riboflavin, porphyrin, nicotinamide, and enzymes will absorb the UV-A light. The UV-B light penetrates the dermis layer and causes DNA structure changes, which lead to wrinkles and a rising risk of skin cancer. Premature skin aging and skin cancer can be prevented with sunscreen preparation containing compounds that can protect the skin from UV radiation. Flavonoid is one of the purslane (Portulaca grandiflora) active metabolites that have the potency to be developed as sunscreen. Objective: This research aimed to determine the ability of purslane (Portulaca grandiflora) magenta flower variety herbs extract cream as a sunscreen as indicated by the %Te, %Tp, and Sun Protective Factor value. Methods: This research was an experimental study with various purslane magenta flower variety herbs extract cream formulas that were tested for their %Te, %Tp, and SPF value with a UV-Vis spectrophotometer. Results: The sunscreen cream preparation with 2.5% of purslane (Portulaca grandiflora) magenta flower variety herb extract had %Te, %Tp, and SPF values of 25.86 ± 2.41%, 36.05 ± 2.82%, and 3.97 ± 0.35 respectively. At the same time, preparations with 5% concentration of extract had %Te, %Tp, and SPF values of 8.23 ± 0.86%, 16.65 ± 0.92%, and 8.03 ± 0.38, respectively. Conclusion: The sunscreen activity of all extract concentration creams was significantly different compared to the negative control (cream base) in all parameters. Flavonoids are the compounds responsible for the sunscreen activity of purslane extract.

Engineered protein-iron and/or gold-protein-iron nanocomposites in aqueous solutions upon UVA light: Photo-induced electron transfer possibilities and limitations

Occurrence/suppression of photo-induced electron transfer (PI-ET) process in solutions of nanocomposites represents a very hot topic in several photo-related research domains. In this work, this phenomenon is investigated in aqueous solutions using iron-containing mono-/bi-metallic nanocomposites that have been engineered through protein-templated syntheses, with the aim to potentially create new biocompatible imaging contrast agents for medical diagnostics. Two types of iron-containing nanocomposites, mono-metallic (protein-Fe) and bi-metallic (Au-protein-Fe), have been synthesized and characterized with the aid of several experimental techniques, such as high-resolution transmission electron microscopy (HR-TEM), steady-state fluorescence, electron paramagnetic resonance (EPR) and light-induced EPR (LEPR). Theoretical model of the N-terminal region of the bovine serum albumin protein interacting with Fe cations and simulations of the EPR spectral features upon UVA light irradiation complemented the material’s analysis. Two iron forms within the mono-/bi-metallic nanocomposites have been detected experimentally: (i)complexed iron cations (giving EPR signal at g = 4.29) and (ii)superparamagnetic iron oxide nanoparticles (SPIONs; expressing EPR resonances at g// = 2.21 and g⊥ = 2.09). Upon UVA-light irradiation (325 nm), PI-ET between the two iron forms have been observed in the protein-Fe nanocomposite; however, this electronic communication is suppressed in the Au-protein-Fe system. The presence of luminescent Au nanoclusters and dissimilar sizes of SPIONs in bi-metallic nanocomposites (around 5 nm vs. approx. 2 nm in the monometallic protein-Fe system) represent the two possible reasons underneath suppression of the PI-ET process in the former. Moreover, OH radicals were detected in aqueous solutions in both iron-containing nanocomposites (Fe and Au/Fe systems) when irradiated at 325 nm for 5 min at r.t. The reported evidence of PI-ET in iron-containing nanocomposite aqueous solutions can thus have a large impact on their potential medical and/or environmental applications.

Development and application of the UVC LED-based spectrophotometer for high frequency online monitoring of nitrate concentration in municipal wastewater

Developing a fast, sensitive and stable sensor for online monitoring nitrate concentration is an urgent need for the optimization of denitrification processes in wastewater treatment plants (WWTPs). In this study, the miniaturized spectrophotometric nitrate sensor was developed using UVC light-emitting diodes (LEDs) coupled with AlGaN or SiC-based photodiodes. The use of novel SiC photodiodes could effectively eliminate UVB and UVA light in the 230 nm LED emission spectra. Replacing 235 nm UVC-LED with 230 nm UVC-LED could effectively increase the detection sensitivity but not the linear range that follows the Lambert-Beer's law. The influences of dissolved organic matter (DOM) on nitrate analysis could be corrected by a unified coefficient α across the NO3--N concentration ranging in 0–50 mg/L. Across the investigated WWTP samples, the correction coefficient α was mainly determined by the fractions of humic substances with apparent molecular weight (MW) of 1.5–9.0 kDa, while the degradation of the large MW proteinaceous biopolymer resulted in dramatic variations of correction coefficient α along the WWTP A/A/O process. Microfiltration membranes with pore sizes ≤ 30 µm could sufficiently eliminate the influences of particles in effluents on photometric nitrate analysis. The ultrafiltration and enhanced coagulation treatment could effectively remove the biopolymer fractions of DOM in wastewater, and thus alleviate its influences on sensitivity and accuracy of nitrate analysis. The spectrophotometric nitrate sensors were successfully applied for on-line monitoring NO3--N concentrations in the influent and effluent of denitrifying biofilter in a municipal WWTP, providing high-frequency feedback signals to precise control of feeding external carbon source.

Printability of recycled feedstock for extrusion additive manufacturing

ABSTRACT The 3D printability of several thermoplastic feedstocks, recycled from post-industrial or post-consumer waste and the properties of printed items are presented and discussed. A preliminary investigation has been conducted with post-industrial scraps of PETG and PLA recycled into printable filaments. A comparison with samples produced with corresponding virgin materials showed similar mechanical characteristics. The printability of virgin, recycled and recycled/UVA exposed ABS pellets from extruded scraps is also compared. Recycled pellets were aged by exposure to UVA light up to 400 hours. The results of mechanical tests of 3D printed specimens indicate that the printability of recycled and artificially aged ABS pellets is still acceptable. Furthermore, nylon fibres recycled from clothing were used as feedstock for 3D printing. A simple and inexpensive recycling process is proposed to recover extruded pellets from nylon t-shirts. On the other hand, 3D printing tests showed that the recycled nylon has some prospects for 3D printing, but only if mixed at low percentage with virgin polymer.

Rapid solid-liquid dynamic extraction of Cachrys pungens Jan ex Guss. aerial parts: influence on the photobiological and antioxidant properties

Cachrys pungens Jan ex Guss. (Apiaceae) is a perennial plant native to Italy and Northwestern Africa. This species is known for its content in furanocoumarins, and the methanolic extract obtained with maceration previously demonstrated significant phototoxicity on 375 melanoma cells. Here, in order to better explain the biological effects, the apoptotic responses on melanoma cancer cell line were verified. The aerial parts were extracted with methanol through an innovative solid–liquid extraction technology, the Naviglio extractor®, and the raw extract was tested for its photobiological properties on human melanoma C32 cells irradiated with UVA light. The in vitro antioxidant potential was assessed as well. The sample exerted a concentration-dependent photocytotoxic activity (IC50 value = 3.00 ± 0.16 µg/mL). In line with these evidences, in C32-treated cells subjected to UV irradiation, further data have reported an up-regulation of p53 and PARP, both proteins involved in apoptotic response and DNA repair.

In situ formation of CuxO/ZnO photocatalysts for efficient simultaneous oxidation of As (III) and adsorption of As (V): Effect of Cu loading.

The introduction of Cu ions onto ZnO leads to alterations in the electrical, optical, and magnetic characteristics of ZnO. These transformations, in turn, result in heightened photocatalytic activity and enhanced stability when employed in the degradation of both organic and inorganic pollutants. Here, a novel photocatalytic-adsorbent system is developed using zinc oxide (ZnO) nanostructures modified with Cu (II) ions in an aqueous solution containing 40mg/L of As (III). The system utilizes UV-A light (365nm) as the irradiation source, and the weight percentage of Cu (II) in the composite varies from 0 to 20%. The experimental results reveal significant adsorption of As (III), ranging from 20 to 50%, depending on the solution's Cu (II) content. Remarkably, the ZnO10%Cu composite exhibits the highest photocatalytic activity, achieving 40% adsorption and complete oxidation of As (III) within 25min of irradiation. Characterization of the composite after the photocatalytic treatment reveals the effective adsorption of As (V) within its structure. Furthermore, no traces of Cu (II) ions are detected in the solution after the reaction, indicating their successful adsorption onto the ZnO surface as Cu (I) and Cu (II) ions. This research marks a significant advancement in harnessing innovative materials for efficient arsenic removal, offering promising insights into the development of novel photocatalytic-adsorbent systems.

Awareness of sun exposure risks and photoprotection for preventing pigmentary disorders in Asian populations: Survey results from three Asian countries and expert panel recommendations.

In this article, we review and discuss the photoprotection behavior of Asians based on the literature, along with a subanalysis of an original online survey, and make recommendations to optimize photoprotection for Asian populations to prevent photoaging and pigmentary disorders. An international panel of eight dermatologists from Asia (China, Korea, Japan, Singapore, Indonesia, and Vietnam) met to discuss sunscreen photoprotection for Asian patients. Additionally, a subanalysis of an online survey by 3000 respondents from three Asian countries (China, Indonesia, and Japan) investigated general public awareness and attitudes to sun exposure. A pre-meeting survey of the eight experts from Asia showed key concerns of Asian patients consulting dermatologists are pigmentary disorders, especially actinic/senile lentigo, post-inflammatory hyperpigmentation, melasma, vitiligo, and Hori's nevus. The survey subanalysis of participants from China, Indonesia, and Japan with predominantly Fitzpatrick skin types (FST) II to IV revealed that they are particularly concerned about sun exposure causing photoaging and pigmentary disorders. Most of the respondents indicated they have limited knowledge on sunlight radiation and appropriate sunscreen protection factors. Only 22%, 13%, and 3% for China, Indonesia, and Japan, respectively, systematically use multiple protective measures (using sunscreen, avoiding midday sun, staying in the shade, wearing a hat, protective clothing, and sunglasses) when exposed to the sun. Further education is needed for Asian populations on the importance of comprehensive daily photoprotection, including broad-spectrum sunscreen, with high UVA and visible light protection, to reduce and prevent photoaging and pigmentary disorders.

Genotoxicity and the stability of N-nitrosomorpholine activity following UVA irradiation

This study investigated N-nitrosomorpholine (NMOR) genotoxicity following UVA irradiation without metabolic activation. Following UVA irradiation, the photo treated NMOR (irradiated NMOR) was directly mutagenic, without UVA or metabolic activation, in the Ames test. The activity was relatively stable, and approximately 79% of the activity remained after 10 days of storage at 37 °C, 4 °C, or −20 °C. Micronuclei (MN) formation was observed in HaCaT cells after treatment with irradiated NMOR without metabolic activation. The action spectrum of MN formation in response to NMOR irradiation followed the NMOR absorption curve. In vivo, MN formation was observed in the peripheral blood reticulocytes of mice injected with irradiated NMOR under the inhibition of cytochrome P450-mediated metabolism of NMOR. Volatile NMOR may attach to environmental materials and be irradiated with environmental UVA light. Photoactivated NMOR-attached air pollutants could float in the air and fall onto the human body, leading to genotoxicity induced by the irradiated NMOR.

Damaging effects of UVA, blue light, and infrared radiation: in vitro assessment on a reconstructed full-thickness human skin.

Exposure to solar radiation can cause a range of skin damage, including sunburn, erythema, skin carcinogenesis, the release of reactive oxygen species (ROS), inflammation, DNA damage, and photoaging. Other wavelengths beyond UVB, such as UVA, blue light, and infrared radiation, can also contribute to the harmful effects of solar radiation. Reconstructed full-thickness human skin has the potential to serve as effective predictive in vitro tools for evaluating the effects of solar radiation on the skin. The aim of this work was to evaluate the damaging effects of UVA, blue light, and infrared radiation in a full-thickness skin model in terms of viability, inflammation, photoaging, tissue damage, photocarcinogenesis. Full thickness skin models were purchased from Henkel (Phenion FT; Düsseldorf, Germany), and irradiated with increasing doses of UVA, blue light, or infrared radiation. Different endpoints were analyzed on the tissues: Hematoxylin-eosin staining, inflammation mediators, photoaging-related dermal markers and oxidative stress marker GPX1, evaluated by real-time quantitative PCR, as well as photocarcinogenesis markers by Western Blot. The results showed differential responses in cytokine release for each light source. In terms of photoaging biomarkers, collagen, metalloproteinases 1 and 9, elastin, and decorin were modulated by UVA and blue light exposure, while not all these markers were affected by infrared radiation. Furthermore, exposure to UVA and blue light induced loss of fibroblasts and modulation of the photocarcinogenesis markers p53 and p21. In conclusion, the presented results suggest that the various wavelengths of solar light have distinct and differential damaging effects on the skin. Understanding the differential effects of UVA, blue light, and infrared radiation can serve as a valuable tool to investigate the efficacy of photoprotective agents in full thickness skin models.

Ultraviolet A and Blue Light Transiently Regulate Total Phenolic and Anthocyanin Concentrations in Indoor-grown Red-leaf Lettuce

In controlled environments, supplementing a light spectrum with ultraviolet A (UVA; 315–399 nm) or blue (B; 400–499 nm) light increases the concentrations of phenolic compounds that can increase quality attributes, such as leaf pigmentation and nutritional quality of lettuce (Lactuca sativa). However, B light and sometimes UVA light can inhibit leaf expansion and biomass accumulation when continuously applied, whereas applying it only at the end of the production cycle can increase lettuce quality with little to no effect on crop yield. Our objective was to quantify the persistency of periodic supplemental UVA or B light and compare end-of-production with continuously applied supplemental light during indoor lettuce production on quality attributes and biomass accumulation. We hypothesized that supplemental UVA or B light would be more effective later, rather than earlier, during production with increasing lettuce quality attributes. We grew ‘Rouxai’ red-leaf lettuce hydroponically at an air temperature of 23 °C under 75 μmol⋅m−2⋅s−1 of red (peak = 664 nm) plus 75 μmol⋅m−2⋅s−1 of warm-white light provided by light-emitting diodes. The supplemental lighting treatments consisted of adding 30 μmol⋅m−2⋅s−1 of UVA (peak= 386 nm) or B (peak = 449 nm) light during the seedling phase (P1; days 4–12), growth phase (P2; days 12–20), finishing phase (P3; days 20–28), or the entire time (ET; days 4–28). Supplemental UVA or B light applied at any individual phase did not inhibit biomass accumulation, whereas enriched B light during the entire production period inhibited fresh mass compared with no supplemental light. Additionally, supplemental UVA or B light during P3 or ET similarly increased total phenolic and anthocyanin concentrations. Finally, applying UVA or B light during P1 or P2 had no residual effect on mature plant growth or quality at harvest. We concluded that the end of the production cycle is the optimal time to apply supplemental UVA or B light to improve lettuce coloration and phenolic content, that earlier application elicits transient responses, and that continuous application improves lettuce quality but inhibits biomass accumulation. Finally, there are potential energy savings by using end-of-production supplemental light compared with continuous application of the same spectrum.

Upscaling of Electrospinning Technology and the Application of Functionalized PVDF-HFP@TiO2 Electrospun Nanofibers for the Rapid Photocatalytic Deactivation of Bacteria on Advanced Face Masks.

In recent years, Electrospinning (ES) has been revealed to be a straightforward and innovative approach to manufacture functionalized nanofiber-based membranes with high filtering performance against fine Particulate Matter (PM) and proper bioactive properties. These qualities are useful for tackling current issues from bacterial contamination on Personal Protective Equipment (PPE) surfaces to the reusability of both disposable single-use face masks and respirator filters. Despite the fact that the conventional ES process can be upscaled to promote a high-rate nanofiber production, the number of research works on the design of hybrid materials embedded in electrospun membranes for face mask application is still low and has mainly been carried out at the laboratory scale. In this work, a multi-needle ES was employed in a continuous processing for the manufacturing of both pristine Poly (Vinylidene Fluoride-co-Hexafluoropropylene) (PVDF-HFP) nanofibers and functionalized membrane ones embedded with TiO2 Nanoparticles (NPs) (PVDF-HFP@TiO2). The nanofibers were collected on Polyethylene Terephthalate (PET) nonwoven spunbond fabric and characterized by using Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy, and Atomic Force Microscopy (AFM) analysis. The photocatalytic study performed on the electrospun membranes proved that the PVDF-HFP@TiO2 nanofibers provide a significant antibacterial activity for both Staphylococcus aureus (~94%) and Pseudomonas aeruginosa (~85%), after only 5 min of exposure to a UV-A light source. In addition, the PVDF-HFP@TiO2 nanofibers exhibit high filtration efficiency against submicron particles (~99%) and a low pressure drop (~3 mbar), in accordance with the standard required for Filtering Face Piece masks (FFPs). Therefore, these results aim to provide a real perspective on producing electrospun polymer-based nanotextiles with self-sterilizing properties for the implementation of advanced face masks on a large scale.

Central Toxic Keratopathy After Collagen Cross-Linking: A Case Series.

The aim of this study was to report a case series of central toxic keratopathy (CTK) after collagen cross-linking (CXL) in keratoconus. This is a retrospective case series between January 2020 and September 2021. In this period, CXL was performed for progressive keratoconus in 964 eyes. CXL was performed using the epithelium-off accelerated protocol in all patients with a riboflavin soak time of 20 minutes and a UVA light exposure of 9 mW for 10 minutes using the Avedro KXL (Glaukos Inc, Aliso Viejo, CA) cross-linking system. Twelve of 964 eyes (1.2%) developed CTK within 1 week of CXL. All patients presented with well-circumscribed, central disciform haze that was broader in the anterior stroma and narrower in the posterior stroma. We noted initial flattening in keratometry up to 3 months post-CXL in these patients, which gradually steepened over 12 months, but did not reach preoperative levels. We also noted exuberant flattening in pachymetry in the first 3 months, which improved over 12 months. There was a statistically significant decrease in pachymetry in patients who developed CTK at 3 and 12 months postoperatively when compared to patients who underwent CXL but did not develop CTK. Several reports of CTK postrefractive surgery have been described previously. However, the association of CXL in the development of CTK has not been described previously. Here, we elucidated the clinical features of CTK after CXL and how it differs from corneal scarring or haze that occurs post-CXL.

Silver-modification of ZnO thin films deposited on Zn-electroplated Cu substrate by thermal shock method for the enhanced photocatalytic performance

Ag-modified ZnO thin films on Zn-electroplated Cu substrate with different Ag-contents were prepared via a simple sol–gel spin-coating procedure followed by a thermal shock method with AgNO3, and then characterized by XRD, Raman, FTIR, FESEM, EDX, and UV-visible absorption spectroscopy. Their photocatalytic performance was evaluated by the degradation of methylene blue. Due to the sol–gel spin-coating process, the film was successfully immobilized on mechanically robust Zn/Cu plates, making it promising for applications in harsh practical conditions and facilitating recovery. When our ZnO thin films were surface-modified with AgNO3 at 1 and 2 mol%, they exhibited the best photocatalytic activity under UVA light and visible light, respectively, which can be explained by the appearance of maze-like architecture on their surface with vertical ZnO walls, surface defects and metallic silver nanoparticles. However, when the Ag-content was increased to 3 mol%, the maze-like structure collapsed, leading to decreases in photocatalytic performance.

Molecular characterization of coastal seawater dissolved organic matter by ultrahigh-resolution mass spectrometry: a photochemical study of the Tokyo Bay, Japan

The coastal seawater in Tokyo Bay contains abundant sulfur (S)-containing DOM compounds because it receives municipal effluents from wastewater treatments. However, the effect of photohalogenation on the molecular composition of these coastal seawater DOM remains unknown. Herein, light irradiation experiments were combined with the Fourier transform ion cyclotron resonance mass spectrometry to investigate the transformation in the molecular composition of coastal seawater DOM during photohalogenation. In total, 3147 S-containing formulae were identified in the coastal seawater, accounting for 33% of the total number and 24% of the full intensity. Moreover, ~ 44% to ~ 67% of CHOS formulae with high molecular weight, aromaticity, and unsaturation were preferentially photodegraded via decarboxylation and desulfonation. Compared with the visible and UVA lights, UVC light exhibited much significant influences on the molecular composition of coastal seawater DOM. Only a few OBCs and OICs were generated during the photohalogenation, mainly via substitution and addition reactions, from CHO-class DOM belonging to lignin-like compounds. Additionally, the novel DBE-0.5O parameter was proposed as a better indicator of the unsaturation of the carbon skeleton than DBE-O. Our findings provided valuable information on the effect of photohalogenation on the molecular composition of the natural coastal DOM under natural sunlight irradiation.Graphical