Search results for "RAYS"
showing 10 items of 1136 documents
Pyrrolo[3,2-h]quinazolines as Photochemotherapeutic Agents
2011
Heteroanalogues of angelicin, pyrrolo[3,2-h]quinazolines, were synthesized with the aim of obtaining new potent photochemotherapeutic agents. Many derivatives caused a significant decrease in cell proliferation in several human tumor cell lines after irradiation with UVA light (GI(50) =15.2-0.2 μM). Their phototoxicity effected apoptosis in Jurkat cells with the involvement of mitochondria (as determined by the loss of mitochondrial membrane potential and production of reactive oxygen species) and lysosomes. The phototoxicity of these compounds could be explained by lipid peroxidation.
Expression profiling of glial genes during Drosophila embryogenesis
2006
AbstractIn the central nervous system of Drosophila, the induction of the glial cell fate is dependent on the transcription factor glial cells missing (gcm). Though a considerable number of other genes have been shown to be expressed in all or in subsets of glial cells, the course of glial cell differentiation and subtype specification is only poorly understood. This prompted us to design a whole genome microarray approach comparing gcm gain-of-function and, for the first time, gcm loss-of-function genetics to wildtype in time course experiments along embryogenesis. The microarray data were analyzed with special emphasis on the temporal profile of differential regulation. A comparison of bo…
Molecular Basis of DNA Photodimerization: Intrinsic Production of Cyclobutane Cytosine Dimers
2008
Based on CASPT2 results, the present contribution establishes for the first time that cytosine photodimer formation (CC) is mediated along the triplet and singlet manifold by a singlet-triplet crossing, (T1/S0)X, and by a conical intersection, (S1/S0)CI, respectively. The former can be accessed in a barrierless way from a great variety of photochemical avenues and exhibits a covalent single bond between the ethene C6-C6' carbon atoms of each monomer. The efficiency of the stepwise triplet mechanism, however, would be modulated by the effectiveness of the intersystem crossing mechanism. The results provide the grounds for the understanding of the potential photogenotoxicity of endogenous and…
Entanglement replication in driven-dissipative many body systems
2012
We study the dissipative dynamics of two independent arrays of many-body systems, locally driven by a common entangled field. We show that in the steady state the entanglement of the driving field is reproduced in an arbitrarily large series of inter-array entangled pairs over all distances. Local nonclassical driving thus realizes a scale-free entanglement replication and long-distance entanglement distribution mechanism that has immediate bearing on the implementation of quantum communication networks.
The ras-related small GTP-binding protein RhoB is immediate-early inducible by DNA damaging treatments.
1995
The low molecular weight GTP-binding proteins RhoA, RhoB, and RhoC are characterized as specific substrates for the ADP-ribosyltransferase C3 from Clostridium botulinum and are supposed to be involved in the organization of the microfilamental network and transformation. rhoB is known to be immediate-early inducible by growth factors and protein-tyrosine kinases. Since increasing evidence indicates overlapping of growth factor- and UV-induced signal pathways, we studied the effect of UV light and other genotoxic agents on early rhoB transcription. Within 30 min after UV irradiation of NIH3T3 cells, the amount of rhoB mRNA increased 3-4-fold. Elevated rhoB mRNA was accompanied by an increase…
Measurement and analysis of broadband UVB solar radiation in Spain.
2012
Measurements of broadband UVB irradiance (290-315 nm) at 14 locations in Spain for the period 2000-2009 have been used to generate instantaneous, hourly and daily values of irradiance (W m(-2)) and radiant exposure (kJ m(-2)). These measurements, and its statistical indices, have been analyzed. For the UVB irradiance, the values corresponding to July (maximum) and December (minimum) have been analyzed as representative of the year during the whole period for all locations. For the UVB radiant exposure, the temporal evolution of daily values has been evaluated for all locations to estimate an average yearly behavior. The accumulated radiant exposure for an average year has also been studied …
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 …
Estimation of external gamma radiation dose in the area of Bory Stobrawskie forests (PL).
2011
The study assessed the radiological risks associated with the presence of natural and artificial radionuclides in the Bory Stobrawskie forests (PL). Using the conversion factors given by UNSCEAR and the measurements results of (232)Th series, (238)U series, (40)K, and (137)Cs specific activities in the 10-cm soil layer the values of absorbed dose (D) and the annual effective dose equivalent derived from terrestrial gamma radiation (E) were calculated. The calculated dose was compared with doses directly measured on the area studied.
The contribution of hydrogen peroxide to the radiosensitizing effect of gold nanoparticles
2019
Abstract Plasmid DNA in aerated aqueous solution is used as a probe to determine whose of the reactive oxygen species (ROS) generated after absorption of ultra-soft X-rays (USX) take part in biomolecule damage in the presence and in absence of Gold Nano-Particles (GNP) and specific scavengers. Citrate-coated GNPs with core sizes of 6, 10 and 25 nm are synthetized and characterized, especially in terms of plasmon band shift, ζ-potential and hydrodynamic radii (respectively 9, 21 and 30 nm). We confirm the radiosensitizing effect of GNP and show that the SSB number per plasmid increases when, for a same mass of gold element, the core size of the gold nanoparticles decreases. Hydroxyl radicals…
Determination of the irradiation field at the research reactor TRIGA Mainz for BNCT.
2009
For the application of the BNCT for the excorporal treatment of organs at the TRIGA Mainz, the basic characteristics of the radiation field in the thermal column as beam geometry, neutron and gamma ray energies, angular distributions, neutron flux, as well as absorbed gamma and neutron doses must be determined in a reproducible way. To determine the mixed irradiation field thermoluminescence detectors (TLD) made of CaF(2):Tm with a newly developed energy-compensation filter system and LiF:Mg,Ti materials with different (6)Li concentrations and different thicknesses as well as thin gold foils were used.