Search results for "PHOTOS"
showing 10 items of 701 documents
Study of the Mode and Efficiency of DNA Binding in the Damage Induced by Photoactivated Water Soluble Porphyrins
2013
We have investigated the DNA binding interactions and in vitro photoactivated DNA damage induced by a neutral water soluble porphyrin derivative 5,10,15,20-tetrakis(2,4,6-trihydroxyphenyl)porphyrin (TTHPP) and its zinc derivative 5,10,15,20-tetrakis(2,4,6-trihydroxyphenyl)porphyrinato zinc(II) (Zn-TTHPP) upon visible light irradiation through various spectroscopic techniques and employing repair endonucleases. These porphyrin derivatives exhibited high affinity toward DNA through groove binding interactions as evidenced through the UV-vis absorption, emission, circular dichroism spectral and viscosity changes. Interestingly, the free base porphyrin derivative, TTHPP generated efficient sing…
The Chameleon on the branches: spectral state transition and dips in NGC 247 ULX-1
2021
Soft Ultra-Luminous X-ray (ULXs) sources are a subclass of the ULXs that can switch from a supersoft spectral state, where most of the luminosity is emitted below 1 keV, to a soft spectral state with significant emission above 1 keV. In a few systems, dips have been observed. The mechanism behind this state transition and the dips nature are still debated. To investigate these issues, we obtained a long XMM-Newton monitoring campaign of a member of this class, NGC 247 ULX-1. We computed the hardness-intensity diagram for the whole dataset and identified two different branches: the normal branch and the dipping branch, which we study with four and three hardness-intensity resolved spectra, r…
Optimising an outdoor membrane photobioreactor for tertiary sewage treatment
2019
[EN] The operation of an outdoor membrane photobioreactor plant which treated the effluent of an anaerobic membrane bioreactor was optimised. Biomass retention times of 4.5, 6, and 9 days were tested. At a biomass retention time of 4.5 days, maximum nitrogen recovery rate:light irradiance ratios, photosynthetic efficiencies and carbon biofixations of 51.7¿±¿14.3¿mg¿N·mol¿1, 4.4¿±¿1.6% and 0.50¿±¿0.05¿kg CO2·m3influent, respectively, were attained. Minimum membrane fouling rates were achieved when operating at the shortest biomass retention time because of the lower solid concentration and the negligible amount of cyanobacteria and protozoa. Hydraulic retention times of 3.5, 2, and 1.5 days …
Comparative Investigation on the Nutrient Composition of Healthy and Injured Spruces of Different Locations
1988
Investigations on the content of cations (Ca2+, K+, Mg2+ and Mn2+) were carried out in spruce trees at two exemplary locations in the Taunus montains (Konigstein) and in the Hunsruck mountains (Hattgenstein) in the course of the vegetation period in 1985 and 1986.
Romas viesnīca: [oriģinālfotogrāfiju albums]
1935
Fotogrāfa vārds reljefā iespiedumā fotogrāfiju apakšējā labajā stūrī, bez datējuma.
Sensitivity of scope modelled GPP and fluorescence for different plant functional types
2014
This study addresses the question which factors are responsible for reported positive correlations between solar induced fluorescence (SIF) and gross primary production (GPP). A sensitivity analysis of the model SCOPE, which simulates photosynthesis, fluorescence emission and radiative transfer in canopies, has been carried out for four different plant functional types (PFT): tropical rainforest, C4 crops, C3 crops, and tundra, located in distinct climate zones: tropical everwet (Af), tropical with seasonal drought (savannah, Aw), temperate (Cf), and continental tundra (Dfd). Literature values for structural and physiological parameters and climate reanalysis data were used as input. The ef…
Optical Gating of Photosensitive Synthetic Ion Channels
2011
4-oxo-4-(pyren-4-ylmethoxy) butanoic acid is used as a photolabile protecting group to show the optical gating of nanofluidic devices based on synthetic ion channels. The inner surface of the channels is decorated with monolayers of photolabile hydrophobic molecules that can be removed by irradiation, which leads to the generation of hydrophilic groups. This process can be exploited in the UV-light-triggered permselective transport of ionic species in aqueous solution through the channels. The optical gating of a single conical nanochannel and multichannel polymeric membranes is characterised experimentally and theoretically by means of current-voltage and selective permeation measurements,…
Intensified oxidative and nitrosative stress following combined ALA-based photodynamic therapy and local hyperthermia in rat tumors.
2003
Oxidative stress-related changes in tumors upon localized hyperthermia (HT), 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) and their combination (ALA+HT) were examined after the observation that the antitumor effects of ALA-PDT could be significantly enhanced upon simultaneous application of HT. Rats bearing s.c. DS-sarcomas (0.6–1.0 ml) on the hind foot dorsum were anesthetized and underwent one of the following treatments: (i) ALA-PDT (375 mg/kg 5-ALA i.v.); (ii) localized HT, 43°C for 60 min; (iii) combined ALA-PDT and HT [=ALA+HT]. Appropriate control experiments were also performed. After treatment, tumors were excised and rapidly frozen for later analysis of nitrosative s…
Enhanced effects of aminolaevulinic acid-based photodynamic therapy through local hyperthermia in rat tumours.
2003
The possibility of enhancing aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) by simultaneous application of localised hyperthermia (HT) was evaluated. Treatments of rat DS-sarcomas included: (i) control, (ii) ALA administration (375 mg kg(-1), i.p.), no illumination, (iii) 'nonthermal' illumination, (iv) ALA-PDT: that is, ALA administration, 'nonthermal' illumination, (v) localised HT, 43 degrees C, 60 min (vi) ALA-PDT+HT: ALA administration with full spectrum irradiation resulting in ALA-PDT and HT. Tumour volume was monitored for 90 days or until a target volume (3.5 ml) was reached. No differences were seen between the first three groups, with all tumours reaching the target …
Rapid inactivation and proteasome-mediated degradation of OGG1 contribute to the synergistic effect of hyperthermia on genotoxic treatments
2013
Inhibition of DNA repair has been proposed as a mechanism underlying heat-induced sensitization of tumour cells to some anticancer treatments. Base excision repair (BER) constitutes the main pathway for the repair of DNA lesions induced by oxidizing or alkylating agents. Here, we report that mild hyperthermia, without toxic consequences per se, affects cellular DNA glycosylase activities, thus impairing BER. Exposure of cells to mild hyperthermia leads to a rapid and selective inactivation of OGG1 (8-oxoguanine DNA glycosylase) associated with the relocalisation of the protein into a detergent-resistant cellular fraction. Following its inactivation, OGG1 is ubiquitinated and directed to pro…