Broadband UVB Research Articles

UVB emitting phosphors based on singly and co-doped Ce3+, Gd3+ in Li4ZrF8 phosphors

Preparation of Li4ZrF8:Ce3+ and Li4ZrF8:Ce3+,Gd3+ phosphors is described. Data on luminescence characteristics are presented. Hydrothermal route was employed for the synthesis. Li4ZrF8 crystallizes in orthorhombic system with Pnma space group. Li atoms are distributed over two sites, both having same coordination of six. Zr is also similarly distributed over two 8 coordinated sites. Li4ZrF8:Ce3+ emits a broad band UVB light, while the emission of Li4ZrF8:Ce3+,Gd3+ is in form of a narrow line around 311 nm attributed to 6P7/2 → 8S7/2. Both phosphors exhibited a broad excitation spectrum with a peak at 253 nm. The excitation and emission properties are thus adequate enough to obtain UVB light sources using a conventional high pressure mercury vapour lamp or an ultraviolet LED.

Comprehensive Modulation of Secondary Metabolites in Terpenoid-Accumulating Mentha spicata L. via UV Radiation.

In plants, secondary metabolites change in response to environmental conditions. These changes co-regulate resilience to stressful environmental conditions, plant growth and development, and interactions between plants and the wider ecosystem, while also affecting soil carbon storage and atmospheric and climatic conditions. The objective of this study was to determine the association between UV exposure and the contents of key metabolites, including amino acids, phenolics, flavonoids, terpenoids, carotenoids, tocopherols, and phytosterols. Mentha spicata plantlets were grown in tissue culture boxes for 30 days and then exposed to a low dose of broadband UV-B (291-315 nm; 2.8 kJm-2 biologically effective UV) enriched light for eight days. Metabolite contents were quantified either immediately after the final UV exposure, or after seven days of recovery under photosynthetically active radiation. It was found that UV promoted the production of flavonoids (1.8-fold) ahead of phenolic acids (unchanged). Furthermore, the majority of monoterpenes and sesquiterpenes, constituents of valuable mint essential oil, were significantly increased through UV treatment (up to 90-fold for α-linalool). In contrast, the contents of carotenoids and tocopherols did not increase following UV exposure. A comparison between plants sampled immediately after UV exposure and after seven days of recovery showed that there was an overall increase in the content of carotenoids, mono- and sesquiterpenes, phenolics, and amino acids following recovery, while the contents of sterols and tocopherols decreased. These UV-induced changes in metabolite profile may have important consequences for agriculture, ecology, and even the global climate, and they also provide an exciting opportunity to enhance crop value, facilitating the development of improved products with higher levels of essential oils and added benefits of enhanced flavour, colour, and bioactive content.

Ultraviolet Resistance of Microorganisms Isolated from Uranium-Rich Minerals from Perus, Brazil.

The district of Perus, located in the city of São Paulo, Brazil, is renowned for its weathered granitic-pegmatitic masses, which harbor a significant number of uraniferous minerals that contribute to ionizing radiation levels up to 20 times higher than the background levels. In this study, aseptically collected mineral samples from the area were utilized to isolate 15 microorganisms, which were subjected to pre-screening tests involving UV-C and UV-B radiation. The microorganisms that exhibited the highest resistance to ultraviolet (UV) radiation were selected for the construction of survival curves for UV-C, broad-band UV-B, and solar simulation resistance testing. Subsequently, the four strains that demonstrated superior survival capabilities under UV radiation exposure were chosen for 16S rRNA gene sequencing. Among these, Nocardioides sp. O4R and Nocardioides sp. MA2R demonstrated the most promising outcomes in the UV radiation resistance assessments, showcasing comparable performance to the well-established radioresistant model organism Deinococcus radiodurans. These findings underscore the potential of naturally occurring high-radiation environments as valuable resources for the investigation of UV-resistant microorganisms. Astrobiology 24, 783-794.

Clinical Applications of Phototherapy in Treating Skin Disorders

Introduction and Purpose: Phototherapy, involving the therapeutic use of ultraviolet and visible light, has been a cornerstone in dermatology for treating various skin disorders. This review aims to consolidate current knowledge on the mechanisms of action and clinical applications of phototherapy, with a focus on enhancing understanding among clinicians and researchers.State of Knowledge: Phototherapy is particularly effective for chronic conditions such as psoriasis, vitiligo, and atopic dermatitis, where traditional therapies might not suffice. The mechanism involves modulation of immune response and inhibition of cellular proliferation, achieved through various wavelengths, including UVA and UVB. Recent advancements have introduced narrow-band UVB, which offers targeted therapy with fewer side effects compared to broad-band UVB. Moreover, the review explores innovations such as LED-based therapies and photodynamic therapy, expanding the spectrum of phototherapeutic options.Summary: Phototherapy remains a vital and evolving treatment modality in dermatology, offering safe and effective management for multiple skin disorders. Its success hinges on precise application and adherence to treatment protocols. Future research should aim to optimize treatment regimens, reduce side effects, and enhance patient compliance to improve outcomes. By advancing our understanding and application of phototherapy, we can better tailor treatments to meet individual patient needs, thereby improving the quality of life for those afflicted with chronic skin conditions.

Exploring the complexities of plant UV responses; distinct effects of UV-A and UV-B wavelengths on Arabidopsis rosette morphology

UV-B radiation can substantially impact plant growth. To study UV-B effects, broadband UV-B tubes are commonly used. Apart from UV-B, such tubes also emit UV-A wavelengths. This study aimed to distinguish effects of different UV-B intensities on Arabidopsis thaliana wildtype and UVR8 mutant rosette morphology, from those by accompanying UV-A. UV-A promotes leaf-blade expansion along the proximal–distal, but not the medio-lateral, axis. Consequent increases in blade length: width ratio are associated with increased light capture. However, petiole length is not affected by UV-A exposure. This scenario is distinct from the shade avoidance driven by low red to far-red ratios, whereby leaf blade elongation is impeded but petiole elongation is promoted. Thus, the UV-A mediated elongation response is phenotypically distinct from classical shade avoidance. UV-B exerts inhibitory effects on petiole length, blade length and leaf area, and these effects are mediated by UVR8. Thus, UV-B antagonises aspects of both UV-A mediated elongation and classical shade avoidance. Indeed, this study shows that accompanying UV-A wavelengths can mask effects of UV-B. This may lead to potential underestimates of the magnitude of the UV-B induced morphological response using broadband UV-B tubes.Graphical abstract

Irradiation of human oral mucosa by 233 nm far UV-C LEDs for the safe inactivation of nosocomial pathogens

The inactivation of multi resistant pathogens is an important clinical need. One approach is UV-C irradiation, which was previously not possible in vivo due to cytotoxicity. Recently, far UV-C irradiation at λ < 240 nm was successfully used on skin with negligible damage. A potential application site is the nasal vestibule, where MRSA accumulates and cannot be treated using antiseptics. We irradiated 3D mucosa models and excised human mucosa with 222 and 233 nm far UV-C in comparison to 254 nm and broadband UV-B. Eradication efficiency was evaluated by counting colony forming units; irritation potential was evaluated by hen’s egg-chorioallantoic membrane assay and trans epithelial electrical resistance; cell viability was assessed by MTT. DNA damage and cell protective mechanisms were evaluated immunohistopathologically. On mucosa models, MRSA reduced by ≈ 5 log10 for 60 mJ/cm2 irradiation at 233 nm. A slightly increased cell viability was observed after 24 h. Lower doses showed lower irritation potential than the positive controls or commercial mouthwash, while 80 mJ/cm2 had strong irritation potential. DNA damage occurred only superficially and decreased after 24 h. On excised human mucosa, < 10% of keratinocytes were affected after 150 mJ/cm2 222 nm or 60 mJ/cm2 233 nm.

The Ultraviolet Irradiation of Keratinocytes Induces Ectopic Expression of LINE-1 Retrotransposon Machinery and Leads to Cellular Senescence.

Retrotransposons have played an important role in evolution through their transposable activity. The largest and the only currently active human group of mobile DNAs are the LINE-1 retrotransposons. The ectopic expression of LINE-1 has been correlated with genomic instability. Narrow-band ultraviolet B (NB-UVB) and broad-band ultraviolet B (BB-UVB) phototherapy is commonly used for the treatment of dermatological diseases. UVB exposure is carcinogenic and can lead, in keratinocytes, to genomic instability. We hypothesize that LINE-1 reactivation occurs at a high rate in response to UVB exposure on the skin, which significantly contributes to genomic instability and DNA damage leading to cellular senescence and photoaging. Immortalized N/TERT1 and HaCaT human keratinocyte cell lines were irradiated in vitro with either NB-UVB or BB-UVB. Using immunofluorescence and Western blotting, we confirmed UVB-induced protein expression of LINE-1. Using RT-qPCR, we measured the mRNA expression of LINE-1 and senescence markers that were upregulated after several NB-UVB exposures. Selected miRNAs that are known to bind LINE-1 mRNA were measured using RT-qPCR, and the expression of miR-16 was downregulated with UVB exposure. Our findings demonstrate that UVB irradiation induces LINE-1 reactivation and DNA damage in normal keratinocytes along with the associated upregulation of cellular senescence markers and change in miR-16 expression.

Far-UVC- and UVB-induced DNA damage depending on skin type.

Far-UVC radiation sources of wavelengths 222 nm and 233 nm represent an interesting potential alternative for the antiseptic treatment of the skin due to their high skin compatibility. Nevertheless, no studies on far-UVC-induced DNA damage in different skin types have been published to date, which this study aims for. After irradiating the skin with far-UVC of the wavelengths 222 and 233 nm as well as broadband UVB, the tissue was screened for cyclobutane pyrimidine dimer-positive (CPD+ ) cells using immunohistochemistry. The epidermal DNA damage was lower in dark skin types than in fair skin types after irradiation at 233 nm. Contrary to this, irradiation at 222 nm caused no skin type-dependent differences, which can be attributed to the decreased penetration depth of radiation. UVB showed the relatively strongest differences between light and dark skin types when using a suberythemal dose of 3 mJ/cm2 . As melanin is known for its photoprotective effect, we evaluated the ratio of melanin content in the stratum basale and stratum granulosum in samples of different skin types using two-photon excited fluorescence lifetime imaging (TPE-FLIM) finding a higher ratio up to skin type IV-V. As far-UVC is known to penetrate only into the upper layers of the viable skin, the aforementioned melanin ratio could explain the less pronounced differences between skin types after irradiation with far-UVC compared to UVB.

PD03 Afamelanotide reduces the ultraviolet radiation erythemal response soon after application in healthy volunteers with skin phototypes II–III

Abstract Afamelanotide is a potent α-melanocyte stimulating hormone analogue that binds to the melanocortin 1 receptor and, over time, promotes tanning, conferring systemic photoprotection. Afamelanotide also has antioxidant properties and may promote repair of ultraviolet (UV) radiation (UVR)-induced DNA damage. The objectives of this study were to examine the short-term impact of afamelanotide on DNA damage repair mechanisms, UVR erythema and melanogenic responses in healthy human skin following exposure to UVR. Healthy men and women (n = 10) volunteers aged 27–43 years (median 34) of skin phototypes II–III were recruited. Reflectance spectrophotometry was performed on six body sites (photoexposed and photoprotected) to assess skin pigmentation, and then a geometric series of erythemally weighted doses (7–80 mJ cm−2) of broadband UVB (∼60% UVB, 40% UVA; Philips TL12) was applied to unexposed upper buttock skin. After 24 h, the minimal erythema dose (MED) was assessed and erythema intensity (CIE a*) was measured at each dose site. A subcutaneous implant of afamelanotide 16 mg was administered; 5 days later, the same UVR dose series was applied to unexposed contralateral upper buttock skin. After 24 h, the MED was assessed and repeat skin reflectance measurements were performed. The overall UVR–erythema dose response (area under curve) showed a significant decrease post-afamelanotide (mean 3.5 vs. 2.7; P = 0.018). There was an apparent increase in the median MED post-afamelanotide (24.5 vs. 29.9 mJ cm−2; not statistically significant). Reflectance measurements showed skin lightness (CIE L*) significantly decreased at only one site (central forehead, from 63.0 to 61.0; P = 0.015), while determination of melanin density by reflectance at 420 and 400 nm showed a statistically significant increase in density at all sites except the right abdomen, with a mean overall increase from 2.5% to 2.9% (P = 0.001). Our results indicate that afamelanotide reduces the overall UVR–erythema dose response in healthy human skin shortly after administration, with a small increase in melanogenesis, suggesting other nonmelanogenic properties of this agent contribute to the erythema protection. Further investigation will examine whether enhanced repair of UVR-induced DNA damage plays a role. Funding sources: research sponsored by CLINUVEL (UK) Ltd.

Pruritus in cutaneous graft-versus-host disease: A systematic review.

Pruritus is a common symptom of cutaneous graft-versus-host disease (GVHD) following haematopoietic stem cell transplantation (HSCT). However, little is known about its prevalence, pathophysiology, perceptual characteristics, impact on quality of life and response to antipruritic therapies. The aim of this review was to determine the current knowledge on pruritus in cutaneous GVHD. The review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analyses statement. Of the 338 studies screened, 13 were included. The prevalence of pruritus in cutaneous GVHD was reported in three studies, ranging from 37.0% to 63.8%. Only four trials used pruritus assessment tools. There was little or no information on the intensity of pruritus, its qualitative perception, the location of pruritus and the impact of pruritus on quality of life. Antipruritic treatments for GVHD-associated pruritus were mentioned in five studies (38.5%), including topical ointments (steroids, tacrolimus and calcipotriene), broadband UVB, systemic antihistamines and oral ursodeoxycholic acid. In conclusion, pruritus in cutaneous GVHD appears to be common, but very little is known about the pathophysiology, impact on quality of life and effective treatment options. Basic research and controlled clinical trials are warranted to improve knowledge and management of this important issue.

UV radiation sensitivity of bacteriophage PhiX174 - A potential surrogate for SARS-CoV-2 in terms of radiation inactivation

&lt;abstract&gt; &lt;p&gt;To minimize health risks, surrogates are often employed to reduce experiments with pathogenic microorganisms and the associated health risk. Due to structural similarities between the enveloped RNA-viruses SARS-CoV-2 and Phi6, the latter has been established as a nonpathogenic coronavirus surrogate for many applications. However, large discrepancies in the UV log-reduction doses between SARS-CoV-2 and Phi6 necessitate the search for a better surrogate for UV inactivation applications. A literature study provided the bacteriophage PhiX174 as a potentially more suitable nonpathogenic coronavirus surrogate candidate. In irradiation experiments, the sensitivity of PhiX174 was investigated upon exposure to UV radiation of wavelengths 222 nm (Far-UVC), 254 nm (UVC), 302 nm (broad-band UVB), 311 nm (narrow-band UVB) and 366 nm (UVA) using a plaque assay. The determined log-reduction doses for PhiX174 were 1.3 mJ/cm&lt;sup&gt;2&lt;/sup&gt; @ 222 nm, 5 mJ/cm&lt;sup&gt;2&lt;/sup&gt; @ 254 nm, 17.9 mJ/cm&lt;sup&gt;2&lt;/sup&gt; @ 302 nm, 625 mJ/cm&lt;sup&gt;2&lt;/sup&gt; @ 311 nm and 42.5 J/cm&lt;sup&gt;2&lt;/sup&gt; @ 366 nm. The comparison of these results with published log-reduction doses of SARS-CoV-2 in the same spectral region, led to the conclusion that the bacteriophage PhiX174 exhibits larger log-reduction doses than SARS-CoV-2, nevertheless, it is a better UV-surrogate at 222 nm (Far-UVC), 254 nm (UVC) and 302 nm (UVB) than the often applied Phi6.&lt;/p&gt; &lt;/abstract&gt;

405 Understanding the biologic regulation and impact of Long Interspersed Nuclear Element (LINE-1) retrotransposon reactivation in keratinocytes undergoing phototherapy treatments.

Narrow band ultraviolet B (NB-UVB) and Broad band ultraviolet B (BB-UVB) are commonly used for the treatment of Atopic Dermatitis (AD) among others, and has been shown by us and others to trigger LINE-1 reactivation in human keratinocytes. LINE-1 constitutes ∼17% of human genome, has played important evolutionary role, and its reactivation may result in deleterious effects leading to DNA damage, cellular senescence and photoaging. We established a model of NB-UVB or BB-UVB irradiation on keratinocytes, and showed that these induced an increase in LINE-1 expression.

High performance broad-band ultraviolet-B to visible photodetection based on planar Al-Zn2SnO4-Al structure

This work presents broad-band ultraviolet-B (UVB) to visible photodetection with a high responsivity and detectivity values based on a simple metal-Zn2SnO4 (ZTO) thin film-metal structure. Al-ZTO-Al based metal-semiconductor-metal planar structure shows high responsivity values of 9.25 A/W, 3.64 A/W, 0.71 A/W, and 0.44 A/W under 280 nm, 300 nm, 460 nm, and 550 nm illuminations at + 5 V bias with detectivity values of 4.06 × 1012 Jones, 1.6 × 1012 Jones, 3.1 × 1011 Jones, and 1.93 × 1011 Jones, respectively. The sensitivity values of ∼103, 4.7 × 102, 3.2 × 102, and 2.25 × 102 have been achieved under 280 nm, 300 nm, 460 nm, and 550 nm illuminations with external quantum efficiency values of 4.1 × 103%, 1.5 × 103%, 1.9 × 102%, and 9.9 ×101%, respectively. Unprecedentedly, from the successive responsivity measurements, an ionization transition level of an in-gap defect in ZTO has been proposed to be peaking at ∼2.3 eV below the conduction band causing the visible light sensitivity. This simple ZTO thin film-based UVB to visible broad-band photodetection is very promising for future optoelectronic applications.

Evaluation of Biological Effects and Transcriptome Changes Induced by LED-Based Narrow-Band UVB Phototherapy.

Ultraviolet (UV), particularly UVB, is widely used in the treatment of skin diseases including psoriasis, atopic dermatitis, vitiligo, mycosis fungoides and pruritus. Recently, there has been a trend of replacing broad-band UVB (BB-UVB) units with narrow-band UVB (NB-UVB), as studies have demonstrated that NB-UVB is more efficacious in the treatment of psoriasis. The purpose of this study is to evaluate the biological effects and transcriptome changes induced by light-emitting diode-based NB-UVB (NB-UVB LED) phototherapy. Cell viability and the cell migration ability were significantly decreased posttreatment, as well as apoptosis and ROS levels were remarkably increased. NB-UVB-induced S phase arrest was observed 12 h postirradiation. Bioinformatics analysis of transcriptome sequencing data revealed that NB-UVB LED irradiation induced dose-depended changes in multiple key signaling pathways, such as PI3K and cytoskeletal-related pathways. The depolymerization of cytoskeleton induced by NB-UVB was observed 24 h posttreatment. In addition, the expression levels of cytoskeleton-related proteins FN1, ITGB4, ITGA1, RAC2 and DOCK1 decreased significantly 12 h after irradiation. Our results indicated that NB-UVB LED may serve as a novel option for the development of NB-UVB phototherapy devices.

Ultraviolet phototherapy for treatment of various dermatoses

Ultraviolet (UV) radiation has been applied to treat many chronic skin diseases. Based on the wavelength, UV radiation consists of three types, namely ultraviolet C (UVC), ultraviolet B (UVB), and ultraviolet A (UVA). The types of UV that are widely used in dermatology are narrowband ultraviolet B (NB-UVB), broadband ultraviolet B (BB-UVB), UVA1, and psoralen combined with UVA (PUVA). The interaction between UV and the skin determines the effectiveness of phototherapy. The biological effects of UV are used in the management of inflammatory skin diseases, malignancies, and various rare dermatoses. Apart from these benefits, UV increases the risk of photoaging and skin cancer. Therefore, further researches are necessary to enhance the effectiveness and safety of phototherapy. This literature review discusses the role of phototherapy in various dermatoses other than psoriasis and vitiligo.

Cyclobutane Pyrimidine Dimers Produced with Narrowband UVB Are on Average More Mutagenic than Those with Broadband UVB in Mouse Skin.

Although narrowband UVB (NB-UVB) has replaced broadband UVB (BB-UVB) because of its greater effectiveness in dermatological phototherapy, it is twice as carcinogenic as BB-UVB at an equivalent inflammatory dose. To clarify the basis of the different genotoxicities, we comparatively evaluated the mutagenicities in mouse skin of the two UVB types along with their efficiencies in the formation of cyclobutane pyrimidine dimer (CPD), which is a major mutagenic DNA photolesion specifically produced by UVR. We found that the mutagenicity averaged per single molecule of CPD was 2.5- and 1.8-fold higher in NB-UVB-exposed epidermis and dermis, respectively, which indicates that NB-UVB is more mutagenic for the skin than BB-UVB at doses producing an equimolar amount of CPD. Analysis of effective wavelengths for UV photolesion formation with each UVB source revealed a remarkable difference in the peak effective wavelengths for CPD formation: 15 nm longer for NB-UVB in the epidermis. Although the analysis of mutation profiles showed largely similar UV-specific signatures between the two UVB types, a relatively stronger preference for UVA-specific mutations was observed for NB-UVB. These results suggest that the difference in the effective wavelengths for CPD formation leads to the different mutagenicities and carcinogenicities between the UVB sources.

Phototherapy in Pediatric Dermatology

Background: Phototherapy is a safe and effective treatment modality for skin diseases in children such as psoriasis, atopic dermatitis, pityriasis lichenoides, vitiligo, cutaneous cell lymphoma, pityriasis rubra pilaris, and other skin disorders. It is reported to be effective with less side effects compare to the administration of systemic medicine. Short and long term side effects should be taken into account when applying this model of therapy, especially in children. Purpose: To identify special considerations regarding the use of phototherapy modalities in the field of dermatology in children. Review: Phototherapy is the use of ultraviolet (UV) radiation for therapeutic purposes. The various wavelengths of UV radiation used for phototherapy have their own respective photochemical and photobiological properties. There are modality choices that have been proven to provide benefits in treating various skin diseases, including broadband UVB and narrowband UVB, psoralen UVA photochemotherapy (PUVA), ultraviolet A 1 (UVA1), and targeting phototherapy. Special considerations regarding the use of this treatment modality in the pediatric population increase with safety and treatment tolerance. Conclusion: Special considerations should be taken when providing phototherapy treatment options to children with skin disorders requiring phototherapy. The therapies are generally well tolerated and mostly have minor adverse side effects, such as sunburn.

Phototherapy in Dermatology

Phototherapy is a therapeutic procedure in dermatology. Phototherapy uses certain ultraviolet wavelengths classified into 3 types,broadband UVB (BBUVB), narrowband UVB (NBUVB), and psoralen UVA (PUVA). The most widely used is NBUVB for treating psoriasis, atopic dermatitis and vitiligo. The mechanism of action of phototherapy is to reduce epidermal proliferation, suppress the immune system, reduce the inflammatory process, and induce repigmentation. Before starting phototherapy, the dose adjustment depends on skin type and minimal erythema dose (MED). Frequency of use is recommended based on the severity of the disease, continuously administered needed. Besides of this therapeutic effect, some contraindications and side effects that need to be considered in the use of phototherapy such as drug interactions, photoallergic and risk of skin malignancy.

More Than Skin Deep - the Effects of Ultraviolet Radiation on Cathepsin K and Progerin Expression in Cultured Dermal Fibroblasts.

IntroductionPhotoaging is a premature skin aging developing secondarily to the excessive exposure to ultraviolet radiation. Due to its complexity, an exact mechanism of photoaging has not been found yet; however, recent research has shown two new emerging players in this process – cathepsin K and progerin.AimTo evaluate how different wavelengths of ultraviolet radiation (UVA, narrowband UVB and broadband UVB) influence cathepsin K and progerin protein and mRNA expression in dermal cultured fibroblasts.Materials and MethodsPrimary human dermal fibroblasts (Detroit 551, ATCC CCL-110) were cultured and irradiated with UVA, narrowband UVB (UVBnb) and broadband UVB (UVBwb). Fibroblasts were irradiated with 2 protocols: single high-dose exposure to UVR with protein/mRNA extraction immediately after exposure, 24 h after exposure and 48 h after exposure, and repeated (0 h, 24 h and 48 h) low-dose exposure to UVR with protein/mRNA extraction 48 h after first exposure.ResultsSingle high doses of UVA, UVBwb and UVBnb resulted in decreased expression of cathepsin K and progerin protein/mRNA in all subsequent time points. Repeated exposure to low doses of UVA results in significant increase of progerin mRNA and significant decrease of progerin protein after 48 h, but repeated exposure to UVBwb and UVBnb resulted in decreased progerin mRNA and protein expression. Repeated exposure to UVA, UVBwb and UVBnb resulted in decreased cathepsin K protein and mRNA expression.ConclusionThe results suggest that there could be another progerin/cathepsin K regulatory pathway, which has not been described yet. Being contradictory with previous research, the influence of ultraviolet radiation on progerin and cathepsin K needs to be further elucidated.

Valorization of waste cabbage leaves by postharvest photochemical treatments monitored with a non-destructive fluorescence-based sensor.

The biosynthesis of polyphenolic compounds in cabbage waste, outer green leaves of white head cabbage (Brassica oleracea L. var. capitata subvar. alba), was stimulated by postharvest irradiation with UVB lamps or sunlight. Both treatments boosted the content of kaempferol and quercetin glycosides, especially in the basal leaf zone, as determined by the HPLC analysis of leaf extracts and by a non-destructive optical sensor. The destructive analysis of samples irradiated by the sun for 6days at the end of October 2015 in Skierniewice (Poland) showed an increase of leaf flavonols by 82% with respect to controls. The treatment by a broadband UVB fluorescent lamp, with irradiance of 0.38Wm-2 in the 290-315nm range (and 0.59Wm-2 in the UVA region) for 12h per day at 17°C along with a white light of about 20μmolm-2s-1, produced a flavonols increase of 58% with respect to controls. The kinetics of flavonols accumulation in response to the photochemical treatments was monitored with the FLAV non-destructive index. The initial FLAV rate under the sun was proportional to the daily radiation doses with a better correlation for the sun global irradiance (R2=0.973), followed by the UVA (R2=0.965) and UVB (R2=0.899) irradiance. The sunlight turned out to be more efficient than the UVB lamp in increasing the flavonols level of waste leaves, because of a significant role played by UVA and visible solar radiation in the regulation of the flavonoid accumulation in cabbage. The FLAV index increase induced on the adaxial leaf side was accompanied by a lower but still significant FLAV increase on the unirradiated abaxial side, likely due to a systemic signaling by mean of the long-distance movement of macromolecules. Our present investigation provides useful data for the optimization of postharvest photochemical protocols of cabbage waste valorization. It can represent a novel and alternative tool of vegetable waste management for the recovery of beneficial phytochemicals.