UVB radiation causes formation of specific DNA damage photoproducts between pyrimidine bases. These DNA damage photoproducts are repaired by a process called nucleotide excision repair. When left unrepaired, UVB-induced DNA damage leads to accumulation of mutations, predisposing affected individuals to carcinogenesis as well as to premature aging. Regulation of nucleotide excision repair is an attractive avenue to preventing or reversing these detrimental consequences of impaired nucleotide excision repair. Here, we review recent studies on molecular mechanisms regulating nucleotide excision repair by extracellular cues and intracellular signaling pathways, with a special focus on the molecular regulation of individual repair factors.

The photocatalytic degradation of aqueous MTBE solution was studied using zinc oxide as a photocatalyst. Complete MTBE removal was achieved within 9 h under visible light irradiation using ZnO particles. MTBE removal is attributed to the visible light excitation of the photocatalyst resulting in the generation of photoexcited electron/hole pairs. This method can be considered as an efficient and complete removal system of MTBE from water.

While NBD derivatives are very popular fluorogenic compounds and their first excited states are well characterized, no study had investigated the ability of these compounds to undergo intersystem crossing. As many other intramolecular charge transfer molecules, NBD derivatives present a triplet state in a nonpolar solvent such as cyclohexane.

Steady-state fluorescence emission spectra of morin in CH₃OH-H₂O (A), and CH₃CN-H₂O mixed solvents (B). (A) λ_ex = 390 nm; (1) 100% CH₃OH (), (2) 80% CH₃OH (), (3) 60% CH₃OH (), (4) 40% CH₃OH (); (B) λ_ex = 365 nm; (1) 100% CH₃CN (), (2) 90% CH₃CN (), (3) 70% CH₃OH (), (4) 50% CH₃OH ().

Bi₂WO₆/Bi₂O₃ can be synthesized by a facile one-pot hydrothermal route with sodium oleate using a super big 200 mL Teflon-lined autoclave. The as-prepared composites possessed smaller band gap and higher visible-light responsive than the pure Bi₂WO₆. The as-prepared composites exhibited enhanced photocatalytic activity for the degradation of RhB under visible-light irradiation, which could be ascribed to their improved light absorption property and the reduced recombination of the photogenerated electrons and holes during the photocatalytic reaction.

Unlike its analogs 2-(2′-hydroxyphenyl)oxazolo[4,5-b]pyridine exists as keto tautomer along as enol in the ground state in several solvents.

Both proton-donating and accepting abilities of alcohols in the H-bonded wire can accumulate to help proton transfer, and the strong acidity and basicity of the alcohols with relatively small structural changes in the wire have larger impacts on reducing the activation energies than those of alcohols that trigger proton transfer.

Flexible dye-sensitized solar cells (DSSCs) with enhanced stability, built on ITO/PEN substrates and using an ionic liquid (IL) electrolyte, have been developed. A 12 nm thick blocking layer, produced by atomic layer deposition, was used to reduce electron recombination, and a 1 μm thick TiO₂ film sensitized with the hydrophobic MK-2 dye was used to improve charge collection and extraction. These flexible DSSCs exhibit comparable efficiency to those cells using a solvent based electrolyte plus significantly improved stability, with a <10% drop in performance after 1000 h aging at 60°C under continuous light illumination.

Using a combination of Molecular Dynamics and QM/MM modeling we have characterized stable interaction modes between acetophenone and DNA. The effects of the macromolecular environment on the acetophenone photophysics have been elucidated, confirming that it is still able to efficiently photosensitize DNA by energy transfer from triplet state. In particular this is due to the maintaining of the quasidegenerescence between the first two acetophenone triplet states that are moreover characterized by a high spin-orbit coupling with the ground state. Our work gives important insights in the triplet sensitization mechanism and on the effect of the environment.

The location of the formyl group at the perimeter of the chlorin ring has a profound effect on the position of the long-wavelength chlorin absorption band. Photophysical studies of synthetic formyl chlorins combined with DFT calculations and use of the tetrapyrrole four-orbital model have identified the molecular physical origin of the observed spectral shifts.

We grew calcifying Emiliania huxleyi under indoor constant light and fluctuating sunlight regimes with or without UV radiation. The growth rate was the highest under the indoor, significantly decreased under fluctuating outdoor solar radiation, especially in the presence of UV radiation. When the UV-exposed cells were regrown under indoor light, the growth recovered slowly, which were predicted to take a month to catch the previous indoor growth rate. The results indicate that the cells, while growing under fluctuating light, require additional energy and resources for maintaining photosynthetic machinery and synthesizing UV-absorbing compounds at the cost of decreased growth rate.

Blue-Diode PAM Fluorescence technology can be used to monitor photosynthetic electron transport in Purple Sulfur Photosynthetic Bacteria. This is an important advance for bacterial photosynthetic studies because now photosynthesis of both purple sulfur and purple nonsulfur photosynthetic bacteria can be easily monitored without recourse to ¹⁴C methods in the laboratory and in lakes and microbial mats.

This study shows that both ultraviolet radiation (UVR) and copper (Cu) have deleterious effects on the macroalgae Pterocladiella capillacea, which toxicity led to drastic cellular changes and failure of protective mechanisms. Although UV radiation demonstrated to be more harmful than Cu, our results clearly indicate a synergistic interaction between the two stressors.

Visual cycle retinoids are highly susceptible to UV-light-mediated photodegradation. However, interphotoreceptor retinoid-binding protein (IRBP), the most abundant protein component of the extracellular matrix surrounding the photoreceptors, affords significant photoprotection. This reveals a novel and important role of IRBP in protecting the retina from toxic retinoid photodegradation products.

Nobiletin inhibited ET plus SCF-triggered production of melanin and expression of MITF/tyrosinase in human melanocytes and a three-dimensional human epidermal model. This is the first research emphasizing the antimelanogenesis potential of nobiletin isolated from citrus and its possibility of beneficial applications in the cosmetic industry.

Exposure of cultured human lens epithelial cells (LECs) to UVA light (25 J cm⁻²), or pretreatment of the cells with an inhibitor (1-chloro-2,4-dinitrobenzene) of thioredoxin reductase (TrxR), produced no damaging cellular effects. However, a combination of the two challenges produced substantial loss of LECs and cell damage, including death (arrows) and threadlike structures (arrowheads). In contrast, depletion of reduced glutathione (GSH) by L-buthionine-(S,R)-sulfoximine, combined with exposure to UVA light, produced only a slight cell loss, with no apparent morphological effects. The results demonstrate an important role for TrxR activity, possibly more so than GSH level, in defending the lens epithelium against UVA light.

Light conditions influence the development of the plant pathogenic fungus Colletotrichum acutatum. Exposures to visible light during fungal growth increased production of conidia and mucilage as well as conidial tolerance to UV. Conidia embedded in the mucilage on sporulating colonies were more tolerant of UV than conidia in suspension that were washed free of mucilage.

The aim of this study is to mimic the inflammatory microenvironment and investigate the anti-inflammatory effect of LLLT at a range of wavelengths (405, 532 and 650 nm) on the AF treated with macrophage-like THP-1 cells conditioned medium (MCM) containing proinflammatory cytokines and chemokines. AF cells exposed to MCM secreted significantly higher concentrations of IL-6, IL-8, IL-1β and TNF-α. LLLT markedly inhibited secretion of IL-6 at 405 nm in a time-dependent manner. Level of IL-8 was significantly decreased at all wavelengths in a time-dependent manner. We showed that MCM can induce the inflammatory microenvironment in AF cells and LLLT selectively suppressed IL-6 and 8 levels.

Mechanism of action of LLLT or LEDT on mitochondria in muscle cells. There is an increased flux of electrons through all the complexes of the electron transport chain, increased pumping of H⁺, increased synthesis of ATP and increased mitochondrial membrane potential as shown by TMRM fluorescence. The result is that muscles can perform much more work when light is delivered 3–6 h before exercise.

CdTe/ZnSe core/shell quantum dots (QDs) were prepared using microwave irradiation with different temperatures which is a very easy and less time-consuming method. The QDs were characterized by spectrofluorimetry, TEM, X-ray fluorescence analysis and Dynamic Light Scattering measurement. A blueshifting of the emission was found when ZnSe was deposited on CdTe QDs. All the QDs were able to visualize in in vitro imaging of chicken tissue and embryo and the QDs prepared at 100°C showed the best result.

Metabolism of trans fat by COX and LOX: The dietary intake of trans fat favors the synthesis of biologically active prostanoids produced during inflammatory processes. After ultraviolet radiation exposure, trans fat supplementation, which is rich in trans fatty acids (TFA), increases the skin thickness, reactive species generation and decreases the skin antioxidant defenses.

Low vitamin D is commonly found in people with HIV. This figure presents the unadjusted proportions of people with 25(OH)D <75 nmol L⁻¹ grouped by UV index categories and the four different study locations in Australia [Cairns (latitude 17°S), Nambour (27°S), Brisbane (28°S) and Melbourne (38°S)]. In this study, we describe these and other factors contributing to serum 25(OH)D levels in people with HIV in Australia. Antiretroviral therapy was also associated with 25(OH)D <75 nmol L⁻¹ which appeared to be modified by cholesterol and warrants further exploration in future studies.

The relationship between vitamin D dose and the International Commission on Non-Ionizing Radiation Protection (ICNIRP) UV exposure is studied from measurements made in Southern Queensland, Australia. The measurements take into account all weather and atmospheric conditions including a major continental dust storm event (NASA MODIS Terra image, 23 September 2009). Personal minimum exposure guidelines for the optimal production of vitamin D are presented for each of the internationally recognized UV index ranges relative to the received ICNIRP exposure. The measured data show that the healthy production of vitamin D can be maintained at subtropical latitude without exceeding ICNIRP exposure guidelines.

James Cleaver's 1968 report of defective DNA repair in patients with xeroderma pigmentosum (XP) inspired scientists at the National Institutes of Health to initiate long-term studies of patients with XP and related disorders. These have led to a better understanding of the role of DNA repair in protection from sunlight-induced cancer of the skin and eyes, in maintaining the integrity of the nervous system and in human development. XP serves as a model of the effectiveness of sun protection and of oral retinoids in prevention of skin cancers.

Sunlight is one of the most ubiquitous hazards for life on Earth. Although some aspects of solar radiation are beneficial (e.g. photosynthesis, vision, vitamin D synthesis), the ultraviolet B (UVB) component causes substantial damage to DNA resulting in debilitating and lethal effects. All organisms are capable of repairing DNA photoproducts and repair pathways are remarkably similar. While DNA repair research often focuses on human diseases and the development of cancer; solar DNA damage is also an important component of ecosystem health and stability. This review provides an overview of DNA repair in non-mammalian taxa relative to ambient UVB stress.

Xeroderma pigmentosum is a genetically heterogeneous recessively inherited disease associated with defective cellular responses to damage induced in DNA by sunlight. Most patients develop numerous skin cancers in sun-exposed sites. Hundreds, or even thousands of such tumors may develop, and metastatic spread of these lesions is the leading cause of death, often at an early age. We have now developed an effective treatment (Figure), administered before most clinically manifest tumors arise, which, combined with sun protection, prevents development of almost all skin cancers in patients with xeroderma pigmentosum. The remainder can readily be identified and excised separately.

Early diagnosis and rigorous protection from daylight can completely prevent the skin problems in XP. Patient XP59BR (left) has had poor protection from daylight and has developed many skin cancers. In contrast, patient XPJCLO was diagnosed in his first year of life, has been rigorously protected from sunlight and has not developed any significant skin lesions. Curiously, despite having similar mutations in the XPD gene, XP59BR has no severe neurological problems, whereas XPJCLO has shown features of neurological degeneration since the age of 2. Photographs published with consent of patient or their family.

Geographical distribution of 26 species of the genus Xiphophorus with three northern species is highlighted. The three species comprising the Rio Grande Platyfish are the only Xiphophorus listed on the IUCN Red List of Threatened Species and this clade as a whole displays significantly reduced DNA repair compared to the other species in the genus.

We have shown profound variation in NER (Nucleotide Excision Repair) capacity in humans, between cell-types and during carcinogenesis. As NER is intimately related to both replication and transcription, it shows a narrow range of functional viability. NER activity and gene expression are epigenetically regulated, although this epigenetic modulation is disregulated during sporadic breast carcinogenesis. We now demonstrate differences in NER capacity in eight adult mouse tissues, including a complete lack of activity in brain, and place this result into the context of our previous work on mouse extraembryonic tissues, normal human tissues and sporadic early stage human breast cancer.