117,302 research outputs found
Induction of apoptosis in Jurkat cells by photoexcited psoralen derivatives: Implications of mitochondrial dysfunctions and caspases activation.
No full textThe prevailing form of cell death in lymphocytes exposed to psoralen plus UVA light (PUVA), was investigated. We studied the well known drug 8-methoxypsoralen (8-MOP) and an angular derivatives: angelicin (ANG). We evaluated the induction of apoptosis in a human tumor T-cell line (Jurkat). Both compounds provoke a significant induction of apoptosis at 24h from irradiation as demonstrated by a remarkable percentage of cells Annexin-V positive. We investigated the effects of the psoralen derivatives upon UVA irradiation on the cell cycle. The flow cytometric analysis of propidium labeled cells indicates that treatment induces, in a dose dependent manner, a massive accumulation of cells, for both compounds, in G2-S phase after 24h from the irradiation. We have focused our attention on the mitochondrial functionality after irradiation in the presence of psoralen derivatives. We evaluated, by flow cytometry, (i) the mitochondrial potential (Deltapsi(mt)), (ii) the production of reactive oxygen species (ROS) and (iii) the oxidation of cardiolipin, a phospholipid restricted to the inner mitochondrial membrane. Furthermore the activation of caspases -3, -8 and -9 was also investigated. The obtained data indicated that, upon UVA irradiation, the two compounds induce a strong decrease in mitochondrial functions and activate caspase-3, -8 and -9
Operation of a 2-stage bioelectrochemical system for groundwater denitrification
No full textNitrate groundwater contamination is an issue of global concern that has not been satisfactorily and efficiently addressed, yet. In this study, a 2-stage, sequential bioelectrochemical system (BES) was run to perform autotrophic denitrification of synthetic groundwater. The system was run at a 75.6 mgNO3−-N L−1NCC d−1 nitrate loading rate, achieving almost complete removal of nitrate (>93%) and Total Nitrogen (TN) (>93%). After treatment in the first stage reactor values of effluent nitrate compatible with the EU and USA limits for drinking water (<11.3 and 10 mgNO3−-N L−1, respectively) were achieved. Nitrite and nitrous oxide were observed in the first stage’s effluent, and were then successfully removed in the second stage. The observed nitrate removal rate was 73.4 ± 1.3 gNO3−-N m−3NCC d−1, while the total nitrogen removal rate was 73.1 ± 1.2 gN m−3NCC d−1. Specific energy consumptions of the system were 0.80 ± 0.00 kWh m−3, 18.80 ± 0.94 kWh kgNO3−-N−1 and 18.88 ± 0.95 kWh kgN−1. Combination of two denitrifying BES in series herein described proved to be effective
Graphitic carbon nitride as a sustainable photocatalyst material for pollutants removal. State-of-the art, preliminary tests and application perspectives
No full textPhotocatalysis is an attractive strategy for emerging pollutants remediation. Research towards the development of new, efficient and effective catalytic materials with high activity under wide irradiation spectra is a highly active sector in material science. Various semiconductor materials have been employed as photocatalysts, including TiO2, SrTiO3, CdS, BiVO4, Ta3N5, TaON, Ag3PO4, and g-C3N4 . The latter is a metal-free, low cost polymer, providing high adsorption and catalytic properties, shown to be promising for photocatalysis applications under visible light. Furthermore, g-C3N4 composites are among the most promising advanced photocatalytical materials that can be produced by green synthesis processes. In this paper, the state-of-the-art of g-C3N4 applications is reviewed, and application perspectives are discussed. Photocatalysis tests with g-C3N4 under Xenon irradiation were performed to gather first-hand information to improve photoreactor design. Xenon light spectrum appears to be a suitable radiation source to replace direct sunlight in engineered pollutants removal processes catalyzed by g-C3N4, in lieu of other currently used heterogeneous photocatalysis processes (e.g., TiO2-UV). LED sources are also very promising due to higher energy efficiency and customizable, catalyzer-specific irradiation spectra
Sustainable processing of dairy wastewater: Long-term pilot application of a bio-electrochemical system
No full textDemographic growth, increasing food demand and non-renewable fuels depletion require new sustainable industrial approaches in all areas of the agro-farming sector. Microbial fuel cells (MFCs) could represent an eco-innovative technology for energy and resources recovery from agrofood processes wastewaters. This study was conducted to: (i) assess the bioelectrochemical treatability of dairy wastewater by means of MFCs; (ii) determine the effects of the organic loading rate (OLR) on MFCs performance; (iii) evaluate the reactors’ overpotentials, and identify possible strategies oriented to their reduction. For this purpose, two replicate MFCs were built and continuously operated for 65 days. The anode chamber was fed with undiluted dairy wastewater at 1 L d−1. An aerated mineral medium was fed to the cathode chamber with the same flow-rate. The study demonstrated that these types of industrial effluents can be treated by MFCs with 82% (average) organic matter removal, recovering a maximum power density of 26.5 W m−3. Coulombic efficiency (CE) of the lab-scale reactors decreased by increasing the OLR (organic loading rate). The highest CE was found to be 24% at a OLR of 3.7 kg COD m−3 d−1. MFCs energy losses were mainly due to cathode reaction (34–39% of total loss) and ionic transport through the membrane (27–33%). Achieved results were better than previously reported MFC-experiences dealing with dairy (or similar) wastewater treatment
Controlled sequential biocathodic denitrification for contaminated groundwater bioremediation
No full textNitrate groundwater contamination is a worldwide concern. In this study, a novel 2-stage, sequential biocathodic denitrification system was tested to perform autotrophic denitrification of synthetic groundwater. The system was operated at different nitrate loading rates (66–301 gNO3 −-N m−3 NCC d−1) at constant NO3 −-N concentration (40 mgNO3 −-N L−1), by varying hydraulic retention time (HRT) during different trials from about 14 to 3 h. The system was able to achieve almost complete removal of nitrate (>95%) and Total Nitrogen (TN) (>92%) at NO3 − loading rates between 66 and 200 gNO3 −-N m−3 NCC d−1. The first stage reactor achieved lower values of effluent nitrate and nitrite than WHO guidelines for drinking water quality (<11.3 mg NO3 −-N L−1, and 0.9 mgNO2 −-N L−1, respectively) up to a nitrate loading rate of 167 gNO3 −-N m−3 NCC d−1; in these conditions the second stage acted mainly as polishing step. From a loading rate of 200 gNO3 −-N m−3 NCC d−1 on, N2O accumulation was observed in the first stage reactor, afterwards successfully removed in the second stage. Maximum nitrate removal rate of the 2-step process was 259.83 gNO3 −-N m−3 NCC at HRT of 3.19 h. The specific energy consumption of the system (SEC) decreased with decreasing HRT, both in terms of mass of nitrate removed (SECN) and volume treated (SECV). The described combination of two bioelectrochemical systems system hence proved to be effective for groundwater denitrificatio
Central role of motichodria and p53 in puva-induced apoptosis in human keratinocytes cell line NCTC-2544.
No full textDespite strong evidence concerning the high efficiency of PUVA therapy (psoralen plus UVA light), its mechanism of action has not yet been fully elucidated. In this study, we have evaluated in a cell line of human keratinocytes (NCTC-2544) the effects of two linear psoralen derivatives, 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP), that are widely used in PUVA therapy and two angular derivatives, Angelicin (ANG) and 4,6,4'-trymetyl angelicin (TMA). All derivatives photoinduce cellular death, TMA being the most active compound. The cell cycle analysis showed that the four derivatives induce, 24 h after irradiation, a cell cycle arrest in G1 phase later followed by massive apoptosis. The G1 arrest is correlated to an increase in the expression of p21(Waf1/Cip1), a protein associated with the cell cycle block and apoptosis. Furthermore, treatment of NCTC-2544 resulted in p53 activation by 5-MOP, 8-MOP, and ANG but not TMA and its phosphorylation at serine-15. The levels of p21(Waf1/Cip1) paralleled p53 protein staining pattern suggesting that p53 activation correlated with p21(Waf1/Cip1) induction. Simultaneous to p53 activation, psoralens induced mitochondrial depolarization, cytochrome c release, mitochondrial production of reactive oxygen species, as well as caspase-3 and -9 activation. Thus these results strongly indicate the necessity of p53 activation and the induction of the apoptotic machinery downstream of mitochondria
Stroke volume index assessment using two minimal invasive devices during hemodynamic postoperative optimization
No full textCARDIAC OUTPUT MONITORING IN CIRRHOTIC PATIENTS: EV1000 VERSUS PULMONARY ARTERY CATHETER- PRELIMINARY DATA
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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