Search results for "Ultraviolet Ray"
showing 10 items of 239 documents
Triazolopyridopyrimidines: an emerging family of effective DNA photocleavers. DNA binding. Antileishmanial activity.
2015
Triazolopyridopyrimidines 3-phenyl-6,8-di(2-pyridyl)-[1,2,3]triazolo[5',1':6,1]pyrido[2,3-d]pyrimidine (1a), 6,8-di(pyridin-2-yl)-[1,2,3]triazolo[1',5':1,6]pyrido[2,3-d]pyrimidine (1b) and 3-methyl-6,8-di(2-pyridyl)-[1,2,3]triazolo[5',1':6,1]pyrido[2,3-d]pyrimidine (1c) were prepared and their electrochemical and luminescence properties were studied in depth. The DNA binding ability of this series of compounds has been investigated by means of UV-vis absorption and fluorescence titrations, steady-state emission quenching with ferrocyanide as well as viscosity measurements. Results have shown that triazolopyridopyrimidine 1a interacts strongly at DNA grooves. This compound also displays pref…
Ten years of measured UV Index from the Spanish UVB Radiometric Network.
2013
An analysis is made of the UV Index (UVI) obtained from the ultraviolet erythemal solar radiation (UVER) data measured by the Spanish UVB Radiometric Network between the years 2000 and 2009. Previously, the daily UVI has been evaluated using two different criteria: (a) the value corresponding to solar noon; and (b) the daily maximum value. The mean percentage of agreement is 92% if we consider the cases for which the difference is zero or one UVI unit. These results are similar to those obtained in a previous work where only 2 years were analyzed. In all the stations the UVI reaches very high values (8-10) in spring-summer, and the very high and extreme (≥ 11) UVI values are more dependent …
Ultraviolet A1 radiation induces nitric oxide synthase-2 expression in human skin endothelial cells in the absence of proinflammatory cytokines.
2001
Skin exposure to ultraviolet radiation from sunlight causes erythema and edema formation as well as inflammatory responses. As some of these ultraviolet-induced effects are potentially mediated by nitric oxide synthases, we examined the role of cytokines and ultraviolet A 1 radiation (340–400 nm) on the expression of the nitric oxide synthase-2 in endothelia of normal human skin biopsies during short-term organ culture as well as expression and activity of the nitric oxide synthase-2 in in vitro cell cultures of human dermal endothelial cells. Both, cytokine challenge (interleukin-1β + tumor necrosis factor-α + interferon-γ) but also ultraviolet A 1 exposure (50 J per cm 2 ) in the absence …
Long-term UVB irradiation affects the immune functions of carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss).
2009
The effects of long-term, low-dose ultraviolet B (UVB) radiation on immune functions of two fish species representing different taxonomic groups, carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss), were assessed in this study. The fish were exposed to 7, 20 or 60 mJ cm(-2) UVB three times per week, for 6 weeks. In carp, UVB exposure affected the respiratory burst activity of blood and head kidney phagocytes, differential blood leukocyte counts and blood chemistry. Phytohemagglutinin (PHA)-stimulated in vitro proliferation responses of blood and head kidney lymphocytes, however, remained unchanged. Rainbow trout tolerated the irradiations with fewer alterations, but significant c…
Activation of c-Jun N-terminal kinase 1 by UV irradiation is inhibited by wortmannin without affecting c-iun expression.
1999
Activation of c-Jun N-terminal kinases (JNKs)/stress-activated protein kinases is an early response of cells upon exposure to DNA-damaging agents. JNK-mediated phosphorylation of c-Jun is currently understood to stimulate the transactivating potency of AP-1 (e.g., c-Jun/c-Fos; c-Jun/ATF-2), thereby increasing the expression of AP-1 target genes. Here we show that stimulation of JNK1 activity is not a general early response of cells exposed to genotoxic agents. Treatment of NIH 3T3 cells with UV light (UV-C) as well as with methyl methanesulfonate (MMS) caused activation of JNK1 and an increase in c-Jun protein and AP-1 binding activity, whereas antineoplastic drugs such as mafosfamide, mito…
Molecular structures and vibrations of m-methylaniline in the S0 and S1 states studied by laser induced fluorescence spectroscopy and ab initio calcu…
2000
Abstract The UV fluorescence excitation and dispersed fluorescence spectra of a jet-cooled m-methylaniline have been obtained for the S1←S0 transition, in which some of the bands have been observed for the first time. The main spectral bands have been assigned by comparison with those of other relevant substituted benzenes. It was found that the spectra exhibit an important feature which is the internal rotation of the methyl group in the electronic ground and excited states. Ab initio calculations at MP2/6-31G* and CIS/6-31G* show that the optimized structure of m-methylaniline in the ground state is not planar with the amino group having sp3 hybridation-like character due to the existence…
The antagonistic effect of UV radiation on warming or nitrate enrichment depends on ecotypes of freshwater macroalgae (Charophytes).
2019
Increases in ultraviolet radiation (UVR), a negative global change factor, affect aquatic primary producers. This effect is expected to be modulated by other global change factors, and to be different for populations adapted to different environments. A common garden experimental approach using freshwater green macroalgae, the cosmopolitan charophyte species Chara hispida and C. vulgaris, allowed us to test whether the beneficial increases in water temperature (T) and nitrate concentration (N) mitigate negative UVR effects. Also, whether these interactions would be not only species-specific but also according to the origin of the population; therefore, two populations of each species were u…
Intracoronary Infusion of Thioflavin-S to Study Microvascular Obstruction in a Model of Myocardial Infarction
2015
Abstract Introduction and objectives Microvascular obstruction exerts deleterious effects after myocardial infarction. To elucidate the role of ischemia-reperfusion injury on the occurrence and dynamics of microvascular obstruction, we performed a preliminary methodological study to accurately define this process in an in vivo model. Methods Myocardial infarction was induced in swine by means of 90-min of occlusion of the mid left anterior descending coronary artery using angioplasty balloons . Intracoronary infusion of thioflavin-S was applied and compared with traditional intra-aortic or intraventricular instillation. The left anterior descending coronary artery perfused area and microvas…
Triplet stabilization for enhanced drug photorelease from sunscreen-based photocages
2021
[EN] Recently, sunscreen-based drug photocages have been introduced to provide UV protection to photoactive drugs, thus increasing their photosafety. Here, combined experimental and theoretical studies performed on a photocage based on the commercial UVA filter avobenzone (AB) and on the photosensitizing non-steroidal anti-inflammatory drug ketoprofen (KP) are presented unveiling the photophysical processes responsible for the light-triggered release. Particular attention is paid to solvent stabilization of the drug and UV filter excited states, respectively, which leads to a switching between the triplet excited state energies of the AB and KP units. Most notably, we show that the stabiliz…
Blue light irradiation suppresses dendritic cells activationin vitro
2013
Blue light is a UV-free irradiation suitable for treating chronic skin inflammation, for example, atopic dermatitis, psoriasis, and hand- and foot eczema. However, a better understanding of the mode of action is still missing. For this reason, we investigated whether dendritic cells (DC) are directly affected by blue light irradiation in vitro. Here, we report that irradiation neither induced apoptosis nor maturation of monocyte-derived and myeloid DC. However, subsequent DC maturation upon LPS/IFNγ stimulation was impaired in a dose-dependent manner as assessed by maturation markers and cytokine release. Moreover, the potential of this DC to induce cytokine secretion from allogeneic CD4 T …