Search results for " DAMAGE"
showing 10 items of 1139 documents
Cytotoxic, immunomodulatory, antimycotic, and antiviral activities of semisynthetic 14-hydroxyabietane derivatives and triptoquinone C-4 epimers
2013
A series of C14-hydroxy derivatives of dehydroabietic acid were synthesised from commercial abietic acid and evaluated for their cytotoxic, antimycotic, and antiviral activities. From these C14-hydroxy derivatives, triptoquinone C-4 epimers were obtained and their immunomodulatory activity was additionally evaluated. None of the tested compounds showed antiviral activity against herpes simplex virus type 1 (HHV-1), and nor did they display antimycotic activity against certain Aspergillus, spp. except for one compound, abieta-8,11,13-trien-14,18-diol. Interestingly, two triptoquinone epimers showed cytotoxic activity, and one of them induced mitochondrial potential loss, DNA damage and cell …
Apaf-1 deficient mouse fibroblasts are resistant to MNNG and MMS-induced apoptotic death without attenuation of Bcl-2 decline.
2005
Abstract Simple alkylating agents induce cell death by activating the apoptotic pathway. In rodent fibroblasts, apoptosis triggered by DNA methylation lesions is executed via the mitochondrial damage pathway. Here, we studied cell death induced by the methylating agents methyl methanesulfonate (MMS) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) in mouse fibroblasts wild-type (wt) and deficient for Apaf-1 (apaf-1 knockout cells). Apaf-1 is an essential component of the apoptosome complex that becomes activated upon cytochrome c release from mitochondria. We show that apaf-1 knockout cells are more resistant to the cytotoxic effect (as measured by WST assay) of methylating agents. This is d…
Die Wirkung von Hybridenwein auf die Leber
1961
Experiments on rats revealed that liver damage caused by allyl alcohol (measured by the rate of necrosis) is enhanced by alcoholic beverages such as ethanol and European or hybride wine. In this respect, wine seems to cause more damage than mere alcohol.
Photochemical and photobiological studies with acridine and phenanthridine hydroperoxides in cell-free DNA.
1997
The acridine and phenanthridine hydroperoxides 3 and 7 were synthesized as photochemical hydroxyl radical sources for oxidative DNA damage studies. The generation of hydroxyl radicals upon UVA irradiation (lambda = 350 nm) was verified by trapping experiments with 5,5-dimethyl-1-pyrroline N-oxide and benzene. The enzymatic assays of the damage in cell-free DNA from bacteriophage PM2 caused by the acridine and phenanthridine hydroperoxides 3 and 7 under near-UVA irradiation revealed a wide range of DNA modifications. Particularly, extensive single-strand break formation and DNA base modifications sensitive to formamidopyrimidine DNA glycosylase (Fpg protein) were observed. In the photooxidat…
Photochemical and Photobiological Studies of a Furonaphthopyranone as a Benzo-spaced Psoralen Analog in Cell-free and Cellular DNA
1997
Photobiological activities of the benzo-spaced psoralen analog furonaphthopyranone 3 have been investigated in cell-free and cellular DNA. The molecular geometry parameters of 3 suggest that it should not form interstrand crosslinks with DNA. With cell-free DNA no evidence for crosslinking but also not for monoadduct formation was obtained; rather, the unnatural furocoumarin 3 induces oxidative DNA modifications under near-UVA irradiation. The enzymatic assay of the photosensitized damage in cell-free PM2 DNA revealed the significant formation of lesions sensitive to formamidopyrimidine DNA glycosylase (Fpg protein). In the photooxidation of calf thymus DNA by the furonaphthopyranone 3, 0.2…
Resolving the Benzophenone DNA-Photosensitization Mechanism at QM/MM Level
2015
International audience; Benzophenone, the parent of the diarylketone family, is a versatile compound commonly used as a UV blocker. It may also trigger triplet-based DNA photosensitization. Therefore, benzophenone is involved in DNA photodamage induction. In the absence of experimentally resolved structure, the mechanism of DNA damage production remains elusive. Employing a hybrid quantum mechanics/molecular mechanics approach, here we address the spin transfer mechanism between this drug and proximal thymine, that is, the DNA nucleobase most prone to suffer triplet damages.
Mini-MALTA: Radiation hard pixel designs for small-electrode monolithic CMOS sensors for the High Luminosity LHC
2020
Journal of Instrumentation 15(02), P02005 (2020). doi:10.1088/1748-0221/15/02/P02005
The Global-Local Approach for Damage Detection in Composite Structures and Rails
2021
Structural components with waveguide geometry can be probed using guided elastic waves. Analytical solutions are prohibitive in complex geometries, especially in presence of structural discontinuities or defects. The Global-Local (GL) approach provides the solution by splitting the waveguide in “local” and “global” regions. The “local” region contains the part of the structure responsible for the complex scattering of an incident wave. What happens in this region cannot be reproduced analytically. The “global” region is regular and sufficiently far from the scatterer, in order to exploit known analytical wave propagation solutions. The proposed GL approach discretizes the local region by re…
Recent results from the ATLAS SCT irradiation programme
2000
Abstract The irradiation facility at the CERN proton synchrotron, set up to irradiate full-size prototypes of silicon microstrip detectors for the ATLAS semiconductor tracker, is described and measurements of the detector currents during irradiation are reported. The detector dark currents can be described by bulk radiation damage models demonstrating the radiation hardness of the detector design and allowing the current damage factor α and the acceptor introduction term β to be determined. Results from testbeam studies of a module with an irradiated detector and binary readout in a magnetic field and with the beam incident over a range of angles are reported. The hit efficiency and spatial…
Radiation damage of heavy crystalline detector materials by 24GeV protons
2013
Abstract Samples of three heavy crystalline materials: PbWO4, Bi4Si3O12, and PbF2 were irradiated in a high-intensity 24 GeV proton beam at the CERN PS to fluencies of 3.8×1013 protons/cm2. The optical transmission radiation damage was measured and all crystals show a shift of the cutoff in the transmission spectrum that is not observed when the crystals are irradiated with γ radiation. This shift of the cutoff under proton irradiation seems to be a general property of the heavy crystalline materials. A mechanism for this proton-induced transmission damage is discussed.