Ultraviolet Exposure Research Articles

Senescence in the ageing skin: a new focus on mTORC1 and the lysosome.

Ageing is defined as the progressive loss of tissue function and regenerative capacity and is caused by both intrinsic factors i.e. the natural accumulation of damage, and extrinsic factors i.e. damage from environmental stressors. Cellular senescence, in brief, is an irreversible exit from the cell cycle that occurs primarily in response to excessive cellular damage, such as from ultraviolet (UV) exposure and oxidative stress, and it has been comprehensively demonstrated to contribute to tissue and organismal ageing. In this review, we will focus on the skin, an organ which acts as an essential protective barrier against injury, insults, and infection. We will explore the evidence for the existence and contribution of cellular senescence to skin ageing. We discuss the known molecular mechanisms driving senescence in the skin, with a focus on the dysregulation of the master growth regulator, mechanistic Target of Rapamycin Complex 1 (mTORC1). We explore the interplay of dysregulated mTORC1 with lysosomes and how they contribute to senescence phenotypes.

Tirbanibulin as a Novel Treatment in Actinic Keratosis: A Literature Review

Introduction and purpose: Actinic keratosis (AK) is a common dermatological condition that primarily affects fair-skinned individuals due to cumulative ultraviolet light exposure, potentially leading to squamous cell carcinoma (SCC). AK therapy is divided into two main branches: lesion-directed therapy (cryotherapy, lasers, and surgical methods) and field cancerization-directed therapy (photodynamic therapy and topical agents). Unfortunately, the occurrence of local skin reactions (LSRs) and the therapy duration counted in weeks disrupt patient compliance. This study aims to review the clinical trials concerning the efficacy, safety, and adverse effects of tirbanibulin, a novel promising treatment for AK, which led to its approval and therapeutic development. Materials and methods: Literature available in PubMed and GoogleScholar databases were reviewed using the following keywords: actinic keratosis; actinic keratosis treatment; tirbanibulin. Results: Tirbanibulin's mechanism involves inducing apoptosis by inhibiting microtubule polymerization, which distinguishes it from other treatments that often cause significant inflammation. Clinical trials demonstrate its high efficacy in clearing AK lesions with a favorable safety profile, leading to regulatory approval. The ease of use and short therapy duration (5 days) ensure patient compliance and satisfaction with the treatment. Conclusion: Further longitudinal studies are necessary to confirm the long-term benefits and positioning of tirbanibulin in AK therapy. Raising public awareness about AK and the importance of early treatment with effective options like tirbanibulin is crucial for improving public health outcomes.

Smart Window with Reversible and Instantaneous Photoluminescence based on Microsphere Structure.

A smart window that dynamically regulates light transmittance is crucial for modern life end-users and promising for on-demand optical devices. The advent of three-dimensional (3D) photonic crystal microspheres has enriched the functions of a smart window. However, the smart window formed by polymer microspheres encounters poor mechanical strength and microstructural defects. Herein, to solve this limitation, we report the microsphere-based smart window composed of tightly packed cross-linked polymer microspheres (as a precursor) containing organic photochromic dyes, followed by compression under a high elastic state. When excited under an ultraviolet supply, our smart window showed a rapid and reversible fluorescent photoluminescence without fatigue (50 cycles). Moreover, the bulk devices with a microsphere cross-linked network structure enable excellent mechanical strength (hardness reached 0.158 GPa) and visible-light transparency. Interestingly, a QR code can be recognized under visible light exposure but not under ultraviolet light exposure because of photoluminescence of the smart window. Our method generally provided a paradigm for various amorphous polymers, which can be regarded as a simple and effective approach to build a versatile strategy to introduce an ideal marketplace with economic and community benefits.

Corneal scarring after epithelium-off collagen cross-linking

Abstract Collagen cross-linking (CXL) is considered as a successful therapeutic approach for corneal conditions like keratoconus and corneal ectasia. Despite its efficacy in stabilizing these conditions, the occurrence of post-CXL scars remains a concern. Keratoconus and other corneal ectasias are characterized by structural weaknesses in the cornea. This weakness contributes to the vulnerability of corneal scar formation. In addition, corneal biomechanics and tissue properties play a significant role in scar development. Procedural factors during CXL, including duration and intensity of ultraviolet light exposure, the concentration and type of riboflavin, and the precise application of treatment, have been identified as potential causes of scar formation. Individual patient factors such as variations in healing response and genetic predispositions, associated ocular allergy, and chronic contact lens wear can also impact scar development post-CXL. Understanding these variables is essential for risk stratification and personalized treatment approaches, ultimately optimizing patient outcomes. In addition, regular follow-up visits and patient education are essential to ensure optimal healing and minimize scar related complications. We have tried to explain the numerous reasons of scarring following epithelium-off CXL by conducting a thorough Medline search and reviewing our clinical images. This review serves as a concise overview of the causes and risk factors associated with scar formation after epithelium-off CXL.

An ultraviolet light data logger for studies of organismal ecology and physiology

Abstract Monitoring environmental conditions over time is essential for understanding how species regulate those conditions to satisfy their physiological needs. Variation in ultraviolet (UV) light exposure, for instance, is crucial for numerous taxa, influencing behaviour as well as essential physiological processes like vitamin D3 synthesis. Yet, despite these considerations, no commercially available data loggers exist to record UV exposures over time, preventing inquiry into this important but neglected fitness demand. To overcome this challenge, I designed the first UV data logger, custom built on the open‐source Arduino platform. This device logs UV exposures (in voltage or converted to UV index) and date‐time information for each UV reading, at user‐defined intervals. The integration of a low‐power timer into the assembly, and its weather‐resistant housing, enables long‐term use (at least several months). The cost of one device (including housing) is under £45/$55 USD. Calibration and performance tests reveal that this device is reliable under various weather conditions and produces accurate UV readings under both artificial lighting and sunlight. Both the device and its customised housing can be easily replicated and expanded upon (e.g. inclusion of additional sensors). Overall, this device represents a crucial first step in our ability to better characterise UV exposure patterns in habitats for physiological ecology studies. Exposure to UV light is adaptive for many types of organisms, both in the wild and in captivity (e.g. zoos and private hobbyists), and so I expect a broad array of scientific and public users alike to benefit from using this device.

Plastic film from the source of anaerobic digestion: Surface degradation, biofilm and UV response characteristics

This study simulates a major environmental scenario involving “organic fertilizer source” plastics, by exploring the key factors influencing the changes in plastic-films during anaerobic digestion (AD), as well as the responses of the anaerobically digested plastics to ultraviolet (UV) radiation exposure. The results demonstrate that the degradation effect of AD on plastics is reflected by their yellowish and ruptured appearance, slightly worn surfaces, hardening and opacity, and fragmentation. AD significantly increases the content of oxygen-containing functional groups and the degree of unsaturation in plastic films, with thermophilic temperature processes proving more effective than those conducted at mesophilic temperatures. Exposure to UV light has been found to amplify the degradative effects, suggesting the potential cumulative impact of AD and UV. Both AD and UV irradiation reduced the hydrophilicity of plastics. In particular, the hydrophobicity of polylactic acid films was completely disrupted under overlay-exposure. Furthermore, microbial populations on plastic surfaces were mainly bacterial. These bacterial populations were primarily influenced by temperature, and moderately by the plastic types. In contrast, archaea were predominantly affected by both temperature and digested substrate. This study offers a theoretical foundation for strategies aimed at preventing and controlling plastic pollution derived from organic fertilizers.

Predicting the thickness loss and recovery of acrylic carpet pile imposed to UV exposure using artificial intelligence

One of the metrics that establishes the carpet quality is its compress and decompress behaviors. In a research, addressed later in the paper, carpet samples with the acrylic pile were exposed to the ultraviolet (UV) exposure for 0, 8, 12, 16, and 20 h. The wear test was then carried out using drum revolutions of 0, 4000, 6000, and 8000. Following that, the samples were subjected to a static stress of 700 KPa for 2 h. After removing the load, the sample thickness was measured every 2 min. Finally, the thickness loss and recovery features were determined. Now in this study, the statistical analysis demonstrated the significance of recovery time, UV exposure, and drum revolutions on the features mentioned above, and in the next step, they were modeled using an artificial neural network (ANN) structure. The genetic algorithm, particle swarm optimization, and gray wolf optimization (GWO) were applied as the alternatives to the backpropagation (BP) algorithm for updating the weights and biases of ANN. In the end, it was found that the thickness loss and recovery could be predicted with 6.92 and 9.14% errors, using ANN-GWO and ANN-BP-GWO, respectively.

Clinical and dermoscopic patterns of idiopathic guttate hypomelanosis

Depigmented skin lesions are of great concern in society, especially in the Indian subcontinent. These comprise many infective and inflammatory conditions that cause apprehension and anxiety among patients due to the social stigma attached to these conditions. Idiopathic guttate hypomelanosis (IGH) appears similar to many depigmented lesions and differentiation of IGH from these conditions is difficult clinically as well as histopathologically. IGH is one of the common causes of acquired leukoderma. It is also called disseminated lenticular leukoderma. The etiology is yet not clearly delineated, probably multifactorial. Various etiological factors have been proposed including ultraviolet (UV) exposure, post-phototherapy (psoralen and UVA monotherapy, narrowband-UVB), aging, genetic factors, trauma, and autoimmunity. Clinically, it is characterized by multiple, discrete porcelain-white round to oval macules of 2–5 mm average size. It most commonly occurs in the elderly. The most common sites observed are chronically sun-exposed areas such as the arm, pretibial regions, and forearm extensors. It is not easy to differentiate IGH from other hypo and depigmented conditions such as vitiligo, pityriasis versicolor, extragenital lichen sclerosus et atrophicus, guttate morphea, and post-inflammatory hypopigmentation. It poses a diagnostic challenge to dermatologists. One has to differentiate depigmented lesions from vitiligo as it carries tremendous social implications as social stigma, especially in India. Research on dermoscopic evaluation is uncommon in the literature, despite the abundance of clinic-epidemiological and histological studies of IGH. Four dermoscopic patterns, namely, petaloid, amoeboid, feathery, and nebuloid have been described. These patterns are specific to IGH and help clinicians to differentiate many depigmented skin lesions from IGH in clinical practice. Patients often seek cosmetic treatment. There has been no standard therapy for this condition. Newer treatment modalities range from topical agents to procedure-based therapies and have enhanced the therapeutic armamentarium.

Aging of microplastics and its photo-catalytic degradation of coexisting tetracycline

Photodegradation processes play a crucial role in the transforming of antibiotics in aqueous environments, while photochemical aging influences the properties of microplastics (MPs). In this study, the efficacy of ultraviolet (UV) irradiation in eliminating tetracycline (TC) was examined. Especially, TC degradation was mediated by polyethylene microplastics (PE-MPs) was subjected to aging through UV exposure and a combination of UV and thermal-activated persulfate treatments. The effects of MPs concentration, salinity, and pH on TC degradation were investigated. The characteristics of aging PE-MPs and the corresponding active free radicals were analyzed to understand the mechanism of TC degradation. The results showed that the existence of PE-MPs significantly influenced TC degradation under photosensitized conditions. However, as the concentration of PE-MPs increased, the degradation rate initially increased and subsequently declined. TC degradation increased from approximately 35 % to 85 % when pH increased from 3 to 11 mediated by aged PE-MPs. Moreover, the TC degradation ability increased with increasing salinity, and a higher aging degree facilitated the photodegradation of TC, achieving a removal rate of 62 %. At the same time, free radical quenching confirmed that the singlet oxygen (1O2), hydroxyl radical (OH), and superoxide radical (O2·−) produced all involved in the photolysis process of TC mediated by PE-MPs, especially 1O2. The analysis of the degradation products of TC and prediction of its toxicity revealed that the ecological risk associated with the degradation solution diminished compared with that of the TC mother solution.

Evaluating the Dermatological Benefits of Snowberry (Symphoricarpos albus): A Comparative Analysis of Extracts and Fermented Products from Different Plant Parts.

Skin ageing is influenced by both intrinsic and extrinsic factors, with excessive ultraviolet (UV) exposure being a significant contributor. Such exposure can lead to moisture loss, sagging, increased wrinkling, and decreased skin elasticity. Prolonged UV exposure negatively impacts the extracellular matrix by reducing collagen, hyaluronic acid, and aquaporin 3 (AQP-3) levels. Fermentation, which involves microorganisms, can produce and transform beneficial substances for human health. Natural product fermentation using lactic acid bacteria have demonstrated antioxidant, anti-inflammatory, antibacterial, whitening, and anti-wrinkle properties. Snowberry, traditionally used as an antiemetic, purgative, and anti-inflammatory agent, is now also used as an immune stimulant and for treating digestive disorders and colds. However, research on the skin benefits of Fermented Snowberry Extracts remains limited. Thus, we aimed to evaluate the skin benefits of snowberry by investigating its moisturising and anti-wrinkle effects, comparing extracts from different parts of the snowberry plant with those subjected to fermentation using Lactobacillus plantarum. Chlorophyll-free extracts were prepared from various parts of the snowberry plant, and ferments were created using Lactobacillus plantarum. The extracts and ferments were analysed using high-performance liquid chromatography (HPLC) to determine and compare their chemical compositions. Moisturising and anti-ageing tests were conducted to assess the efficacy of the extracts and ferments on the skin. The gallic acid content remained unchanged across all parts of the snowberry before and after fermentation. However, Fermented Snowberry Leaf Extracts exhibited a slight decrease in chlorogenic acid content but a significant increase in ferulic acid content. The Fermented Snowberry Fruit Extract demonstrated increased chlorogenic acid and a notable rise in ferulic acid compared to its non-fermented counterpart. Skin efficacy tests revealed that Fermented Snowberry Leaf and Fruit Extracts enhanced the expression of AQP-3, HAS-3, and COL1A1. These extracts exhibited distinct phenolic component profiles, indicating potential skin benefits such as improved moisture retention and protection against ageing. These findings suggest that Fermented Snowberry Extracts could be developed into effective skincare products, providing a natural alternative for enhancing skin hydration and reducing signs of ageing.

The risk of ultraviolet exposure for melanoma in Fitzpatrick skin types I-IV: A 20-year systematic review with meta-analysis for sunburns.

Within the last two decades, no studies have comprehensively reviewed the risk of varying types of ultraviolet (UV) exposure on melanoma in fairer skinned individuals. Our research objective was to determine whether or not there was a change in the risk of UV exposure with development of melanoma in Fitzpatrick skin types I-IV based on more recent data over the past 20 years. We performed a systematic review from January 2002 to December 2021 analysing UV exposure and melanoma risk in Fitzpatrick type I-IV individuals. Out of 19,852 studies, 26 met inclusion criteria. Data spanned subjects from national and multinational cohorts (USA, Europe, Australia, Asia and South America). Twenty studies (77%, 20/26) identified a significant association between UV exposure and melanoma incidence. Sunburn was the most commonly assessed risk factor. Sunburn studies encompassed 3417 melanoma and found positive significant odds ratios (OR [95% CI]) in 11 out of 13 studies, ranging from 1.23 [1.01-1.49] to 8.48 [4.35-16.54]. Pooled analysis of the risk of melanoma with sunburn history found an unadjusted odds ratio of 1.66 [1.40-1.97] and adjusted odds ratio of 1.23 [1.04-1.46]. Cumulative sun exposure, measured as number of hours of sun exposure or calculated UV flux, was the second most common risk factor, encompassing 913 melanomas with positive significant ORs ranging from 1.1 [1.0-1.2] to 5.2 [2.1-12.5]. For other forms of UV exposure, a majority of studies showed an association with UV index (6/9), outdoor leisure activity (3/3) and left-sided laterality (1/1). Overall, UV exposure should continue to be considered a modifiable risk factor for melanoma in individuals of fairer skin.

Changes in the incidence of melanoma in Australia, 2006-2021, by age group and ancestry: a modelling study.

To estimate the incidence of melanoma in Australia among people with ancestries associated with low, moderate, or high risk of melanoma, by sex and 5-year age group; to establish whether age-specific incidence rates by ancestry risk group have changed over time. Modelling study; United States (SEER database) melanoma incidence rates for representative ancestral populations and Australian census data (2006, 2011, 2016, 2021) used to estimate Australian melanoma incidence rates by ancestry-based risk. Australia, 2006-2021. Age-specific invasive melanoma incidence rates, and average annual percentage change (AAPC) in age-specific melanoma rates, by ancestry-based risk group, sex, and 5-year age group. The proportion of people in Australia who reported high risk (European) ancestry declined from 85.3% in 2006 to 71.1% in 2021. The estimated age-standardised melanoma incidence rate was higher for people with high risk ancestry (2021: males, 82.2 [95% confidence interval {CI}, 80.5-83.8] cases per 100 000 population; females, 58.5 [95% CI, 57.0-59.9] cases per 100 000 population) than for all Australians (males, 67.8 [95% CI, 66.5-69.2] cases per 100 000 population; females, 45.4 [95% CI, 44.3-46.5] cases per 100 000 population). AAPCs were consistently positive for Australians aged 50 years or older, both overall and for people with high risk ancestry, but were statistically significant only for some age groups beyond 65 years. AAPCs were negative for people aged 34 years or younger, but were generally not statistically significant. Melanoma incidence has declined in some younger age groups in Australia, including among people with high risk ancestry. Social and behavioural changes over the same period that lead to lower levels of ultraviolet radiation exposure probably contributed to these changes.

Bilateral Production Shield Enabling Highly Efficient Perovskite Photovoltaics.

Enhancing the intrinsic stability of perovskite and through encapsulation to isolate water, oxygen, and UV-induced decomposition are currently common and most effective strategies in perovskite solar cells. Here, the atomic layer deposition process is employed to deposit a nanoscale (≈100nm), uniform, and dense Al2O3 film on the front side of perovskite devices, effectively isolating them from the erosion caused by water and oxygen in the humid air. Simultaneously, nanoscale (≈100nm) TiO2 films are also deposited on the glass surface to efficiently filter out the ultraviolet (UV) light in the light source, which induces degradation in perovskite. Ultimately, throughthe collaborative effects of both aspects, the stability of the devices is significantly improved under conditions of humid air and illumination. As a result, after storing the devices in ambient air for 1000h, the efficiency only declines to 95%, and even after 662h of UV exposure, the efficiency remains at 88%, far surpassing the performance of comparison devices. These results strongly indicate that the adopted Al2O3 and TiO2 thin films play a significant role in enhancing the stability of perovskite solar cells, demonstrating substantial potential for widespread industrial applications.

Pulsed corneal crosslinking in the treatment of Keratoconus: a systematic review and meta-analysis.

Corneal crosslinking (CXL) procedures are the treatment of choice in halting progressive corneal ectasia and preserving visual acuity due to keratoconus. Pulsed crosslinking (P-CXL) was developed using intermittent pulsing ultraviolet (UV) light to mitigate the depletion of oxygen levels that occurs with continuous UV exposure in standard crosslinking protocols (C-CXL). This study aimed to explore the use of P-CXL in the treatment of keratoconus and determine whether the availability of oxygen in P-CXL carries superior efficacy outcomes as an alternative to C-CXL modalities. This review was undertaken in accordance with PRISMA guidelines. A search of several databases conducted with two separate reviewers resulted in 29 papers meeting inclusion criteria for the review, 14 selected for meta-analysis. Primary outcomes assessed by the included papers included maximum keratometry (Kmax), corrected and uncorrected distance visual acuity (CDVA, UDVA), and secondary outcomes included central corneal thickness (CCT), endothelial cell count and demarcation line. Statistical analyses were carried out on Review Manager 5.4 and the meta-analysis employed a random-effects model, which estimated the weighted effect size of raw means using inverse variance weights. At 12 months P-CXL showed statistically significant reductions in Kmax (-0.75 D; p < 0.001) and improvement in CDVA (-0.10 logMAR; p < 0.001) compared to baseline. The meta-analysis of comparative studies determined that mean differences in Kmax, CDVA, UDVA, Kmean and CCT after 12 months were not statistically significant between pulsed and continuous crosslinking groups. Overall, P-CXL is effective in improving visual acuity and keratometry outcomes in keratoconus. The meta-analysis did not show a statistically significant difference in Kmax and CDVA between P-CXL and C-CXL, indicating a non-inferiority of P-CXL. However, findings of the meta-analysis are limited by the fact that different energy levels and exposure times were used for P-CXL in comparison to C-CXL in some studies, making it unsuitable to determine whether the efficacy of CXL is improved by the use of pulsed light. What is Known • Pulsed crosslinking (P-CXL) uses intermittent UV light to prevent oxygen depletion when using higher energy protocols, unlike continuous UV exposure in standard continuous crosslinking (C-CXL). • This should theoretically enhance the efficacy of the treatment by maintaining higher oxygen levels that are crucial to the cross-linking process. • There are no systematic reviews or meta-analyses directly comparing the efficacy or safety of P-CXL to C-CXL. What is New • Meta-analysis revealed differences in keratometry between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (Kmax -0.04 dioptres; p = 0.84). • Meta-analysis revealed differences in visual acuity between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (CDVA -0.01 logMAR letters; p = 0.57). • The use of intermittent pulsing in higher energy CXL protocols renders statistically similar outcomes as continuous light exposure at equivalent fluence (7.2 J/cm2).

Recent Advances in Metal-Oxide-Based Photoresists for EUV Lithography.

Extreme ultraviolet lithography (EUVL) is a leading technology in semiconductor manufacturing, enabling the creation of high-resolution patterns essential for advanced microelectronics. This review highlights recent progress in inorganic metal-oxide-based photoresists, with a focus on their applications in EUVL. The unique properties of zinc-based, tin-oxygen, and IVB group inorganic photoresists are examined, showcasing their enhanced chemical reactivity and precise patterning capabilities. Key advancements include the development of zinc oxide and tin oxide nanoparticles, which demonstrate significant improvements in photon absorption and solubility under extreme ultraviolet exposure. Additionally, the review delves into the photochemical reactions of tin-oxygen clusters and the influence of various ligands on film density and cross-linking. The findings suggest that these inorganic photoresists not only improve photolithographic performance but also hold potential for broader applications, such as pyroelectric infrared sensors and 3D printing. Future research directions are outlined, including the optimization of process parameters, the exploration of new ligand and metal combinations, and the evaluation of the environmental benefits of inorganic photoresists over traditional organic ones. These advancements are poised to further enhance the resolution and patterning capabilities required for next-generation semiconductor devices.

Oxidative State in Cutaneous Melanoma Progression: A Question of Balance.

Reactive oxygen species (ROS) are highly bioactive molecules involved not only in tissue physiology but also in the development of different human conditions, including premature aging, cardiovascular pathologies, neurological and neurodegenerative disorders, inflammatory diseases, and cancer. Among the different human tumors, cutaneous melanoma, the most aggressive and lethal form of skin cancer, is undoubtedly one of the most well-known "ROS-driven tumor", of which one of the main causes is represented by ultraviolet (UV) rays' exposure. Although the role of excessive ROS production in melanoma development in pro-tumorigenic cell fate is now well established, little is known about its contribution to the progression of the melanoma metastatic process. Increasing evidence suggests a dual role of ROS in melanoma progression: excessive ROS production may enhance cellular growth and promote therapeutic resistance, but at the same time, it can also have cytotoxic effects on cancer cells, inducing their apoptosis. In this context, the aim of the present work was to focus on the relationship between cell redox state and the signaling pathways directly involved in the metastatic processes. In addition, oxidative or antioxidant therapeutic strategies for metastatic melanoma were also reviewed and discussed.

Expression, Purification, and Anti-UV Irradiation Effect of RsSOD on HCE-T Human Corneal Epithelial Cells.

Superoxide dismutase (SOD) is a class of enzymes that catalyze the disproportionation of superoxide anion radicals into hydrogen peroxide and oxygen. It can remove excessive free radicals in organisms and acts as a potent antioxidant, cleaning free radicals generated by radiation and protecting cells from oxidative damage. In this study, we obtained a MnSOD gene from the radiation-resistant bacterium Radiobacillus sp. (RsSOD) and constructed its recombinant expression vector through gene synthesis. The recombinant RsSOD protein was efficiently expressed using IPTG induction, and purified via repeated freezing and thawing, heating, and DEAE anion-exchange chromatography. The purified RsSOD exhibited an enzyme activity of 2072.5 U/mg. Furthermore, RsSOD was demonstrated to have robust resistance to high temperatures, acid, alkali, and artificial intestinal fluid. Further studies were performed to investigate the radiation resistance of RsSOD against ultraviolet (UV) irradiation in human corneal epithelial (HCE-T) cells. The results indicated that a low concentration of RsSOD (6.25 U/mL) could promote HCE-T cell proliferation and protect these cells from damage caused by both long-term and short-term UV exposure, effectively reducing apoptosis induced by short-term UV irradiation. These findings suggest that the RsSOD protein possesses significant anti-UV irradiation property and is expected to be a candidate for treating ocular radiation-related diseases.

Influence of SU-8 curing parameters on the terahertz absorption characteristics

A plethora of polymers are excellent candidates that can be utilized to build various terahertz (THz) based systems for sensing and microfluidics. SU-8 is a versatile epoxy-based polymer with excellent properties, such as biocompatibility and good mechanical properties. Nevertheless, the impact of curing parameters on the THz absorption characteristics of SU-8 remains uncertain. This study explores the impact of various curing conditions on the THz absorption properties of SU-8. The aim is to establish a correlation between THz absorption and the polymer's cross-linking characteristics. Therefore, three key curing parameters have been examined: time, temperature, and ultraviolet (UV) exposure dose. The SU-8 samples that are cured under different conditions are examined using THz Time-Domain Spectroscopy (THz-TDS) to estimate the THz absorption coefficient. Next, the swelling experiment is conducted to evaluate the polymer cross-linking of the cured samples. The results show that curing conditions and, thus, cross-linking routines significantly influence THz wave propagation and attenuation within SU-8 samples. The findings recommended using an optimal curing dose for SU-8 spanning 1240 mJ/cm2 to 1860 mJ/cm2 which results in a relatively lower absorption coefficient while still maintaining a higher state of cross-linking. This research establishes a crucial link between SU-8 processing and its THz response. It can lay the foundation for tailored SU-8 polymer with optimized THz transmission for novel and customized biosensing and microfluidic devices.

Ultraviolet Light Resistance on the Properties of Polyurethane Coating with the Addition of Chlorinated Rubber

Resistance to ultraviolet light is an essential factor that coating materials must possess, especially for outdoor applications. In this study, the effect of ultraviolet light exposure on the properties of polyurethane coating with the addition of chlorinated rubber was systematically examined. The ultraviolet light exposure was performed using an ultraviolet weathering tester for 500 hours. The samples were investigated through mechanical testing, complemented by scanning electron microscope and Fourier transform infrared spectroscopy. The increase in the tensile strength and elongation at break of the polyurethane coating with the addition of chlorinated rubber was observed and compared to the pristine sample. In the beginning of the ultraviolet exposure, the tensile strength increased 486% and 114% for pristine polyurethane and polyurethane/chlorinated rubber until of 80 hours ultraviolet exposure, indicating repolymerization during the ultraviolet exposure. It was confirmed by the Fourier transform infrared spectra which showed an increase in peak intensity at wave number of 1712 cm־ˡ which indicated C=O bond in the polyurethane. The surface morphology showed micro-cracking caused by ultraviolet exposure. Finally, it was concluded that the addition of chlorinated rubber improved the resistance to ultraviolet light.

Effect of UV exposure and natural aging on the in vitro PAHs bioaccessibility associated with tire wear particles in soil

Tire wear particles (TWP), as an emerging type of microplastics, are a significant source of contaminants in roadside soils due to their high concentration of pollutants, including polycyclic aromatic hydrocarbons (PAHs). This study explored the impact of ultraviolet (UV) exposure and natural aging on the in vitro bioaccessibility of PAHs associated with TWP in soil on a China-wide scale. Our findings suggested that UV exposure amplified the negative charge of TWP by 75 % and increased the hydrophobic groups on the particle surface. The bioaccessibility of 3- and 4-ring PAHs in TWP was significantly (p < 0.05) heightened by UV exposure. After 20 types of soils containing 2 % UV-exposed TWP underwent natural aging, the bioaccessibility of PAHs saw a significant decrease (p < 0.05) to 16–48 %, compared to 28–96 % in the unaged group. Soil pH and electrical conductivity (EC) were the two primary soil properties positively influencing the reduction of in vitro PAHs concentration and PAHs bioaccessibility. According to the prediction results, soils in southern China presented the highest potential region for the release of bioaccessible PAHs from TWP, highlighting the regional specificity of environmental impact. Our study provides valuable insights into the biological impact of PAHs associated with TWP on a regional scale, and offers scientific evidence for targeted soil risk management strategies.