171,391 research outputs found
Chapter 53 Activation mechanisms of chemical toxicity
No full textThe toxic potential of a chemical is largely dependent on the nature of enzymes present in the living organism at the time of exposure. If these favor activation, high levels of reactive intermediates will be generated, largely in the liver, overwhelming the deactivation mechanisms and provoking toxicity Reactive intermediates may also be transported to other tissues, distant to the site of their formation, to manifest toxicity/carcinogenicity. The levels of these enzyme systems in animals and humans are genetically determined but are also modulated by exposure to environmental chemicals, many of which are derived from the diet. It is now possible, using sophisticated computer-assisted techniques, to predict whether a chemical is likely to form a reactive intermediate, thus enabling the safety evaluation of chemicals at the earliest stage of development, before chemical synthesis is undertaken (Ioannides et al., 1993). © 1997 Elsevier B.V. All rights reserved
La Corte EDU condanna nuovamente lo Stato italiano per l’emergenza rifiuti in Campania: un nuovo passo nell’emersione del diritto fondamentale a vivere in un ambiente salubre
No full textLa sentenza della Corte europea dei diritti dell’uomo, 19 ottobre 2023, Locascia e altri c. Italia, accerta nuovamente la violazione dell’art. 8 della Convenzione da parte dello Stato italiano con riferimento all’emergenza rifiuti che ha interessato il territorio della Regione Campania tra il 1994 e il 2009. La sentenza riconosce che una situazione di grave inquinamento può determinare la violazione del diritto al rispetto della vita privata e familiare, ponendosi sulla scia della precedente giurisprudenza della Corte, che ha interpretato evolutivamente la Convenzione riconoscendo l’esistenza di diritto all’ambiente salubre, ma solo in via indiretta, come conseguenza dell’obbligo di garantire i diritti direttamente previsti in favore dell’individuo, non come diritto in sé
The modulation by arylamines of the in vitro formation of superoxide anion radicals and hydrogen peroxide by rat liver microsomes.
No full textChapter 53 Activation mechanisms of chemical toxicity
No full textThe toxic potential of a chemical is largely dependent on the nature of enzymes present in the living organism at the time of exposure. If these favor activation, high levels of reactive intermediates will be generated, largely in the liver, overwhelming the deactivation mechanisms and provoking toxicity Reactive intermediates may also be transported to other tissues, distant to the site of their formation, to manifest toxicity/carcinogenicity. The levels of these enzyme systems in animals and humans are genetically determined but are also modulated by exposure to environmental chemicals, many of which are derived from the diet. It is now possible, using sophisticated computer-assisted techniques, to predict whether a chemical is likely to form a reactive intermediate, thus enabling the safety evaluation of chemicals at the earliest stage of development, before chemical synthesis is undertaken (Ioannides et al., 1993). © 1997 Elsevier B.V. All rights reserved
Benzidine modulates the NADPH-dependent generation of superoxide anion radical by rat liver microsomes
No full textSpatial evolution of the US urban system.
No full textWe examine spatial features of the evolution of the US urban system usingUS Census data for 1900 – 1990 with non-parametric kernel estimation techniques that accommodate the complexity of the urban system. We consider spatial features of the location of cities and city outcomes in terms of population and wages. Our results suggest a number of interesting puzzles. In particular, we find that city location is essentially a random process and that interactions between cities do not help determine the size of a city. Both of these findings contradict our theoretical priors about the role of geography (physical and economic) in determining city outcomes. More detailed study suggests some solutions that allow us to restore a role for geography but a number of puzzles remain.
MEG's ability to localise accurately weak transient neural sources
No full textObjective: to investigate the accurate localisation of weak, transient, neural sources under conditions of varying difficulty.Methods: multiple dipolar sources placed within a head-shaped phantom at superficial and deep locations were driven separately or simultaneously by a short-lasting current with varied amplitudes. Artificial MEG signals that were very similar to the human High Frequency Oscillations (HFO) were produced. MEG signals of HFO were also recorded from median nerve stimulation. Different inverse techniques were used to localise the phantom dipoles and the human HFO generators.Results: the human HFO were measured around 200 and 600 Hz by using only 120 trials. The 200 Hz HFO were localised to BA3b. The superficial phantom’s source was localised with an accuracy of 2–3 mm by all inverse techniques (120 trials). The ‘subcortical’ source was localised with an error of 5 mm. Localisation of deeper ‘thalamic’ sources required more trials.Conclusion: MEG can detect and localise weak transient activations and the human HFO with an accuracy of a few mm at cortical and subcortical regions even when a small number of trials are used.Significance: localizing HFO to specific anatomical structures has high clinical utility, for example in epilepsy, where discrete HFO appears to be generated just before focal epileptic activity<br/
Special Edition on GIS in Cultural Heritage
No full textA survey on the use of GIS and Data Standards in Archaeology ........491
Berdien De Roo, Jean Bourgeois and Philippe De Maeyer
Approaching a Mortuary Monument Landscape using GIS- and ALSGenerated
3D Models ...............................................................................509
Ole Risbøl, Troels Petersen and Gro B. Jerpåsen
GIS and Landscape Archaeology: A Case of Study in the Argentine
Pampas .......................................................................................................527
Natalia Mazzia and Juan C. Gómez
An Intercultural Approach for the Protection and Promotion of Common
Cultural Heritage: The Case of Byzantine Monuments in Serbia ..........547
E. Oikonomopoulou, E. T. Delegou, N. Vesic, J. Sayas
and A. Moropoulou
Settlement’s Dynamics in Western Sicily between VIII E IV Sec. B.C.
A Geographic Information System to Research.....................................569
Sebastiano Muratore
Modelling Archaeological and Geospatial Information for Burial Site
Prediction, Identification and Management...........................................585
Aikaterini Balla , Gerasimos Pavlogeorgatos, Despoina Tsiafakis
and George Pavlidis
Using GIS to Integrate Old and New Archaeological Data From Stone
Age Deposits in Karonga, Malawi............................................................611
Jessica C. Thompson, Menno Welling
and Elizabeth Gomani-Chindebvu
Mapping of Building Materials and Consevation Interventions using GIS:
the Case of Sarantapicho Acropolis and Erimokastro Acropolis
in Rhodes ....................................................................................................631
E. T. Delegou, E. Tsilimantou, E. Oikonomopoulou, J. Sayas, C. Ioannidis
and A. Moropoulou
GIS-Based Tools for the Management and Dissemination of Heritage
Information in Historical Towns. The Case of Santiago de Compostela
(Spain) .........................................................................................................655
César Parcero-Oubin~a, Pedro Vivas White, Alejandro Güimil-Farin~a,
Rebeca Blanco-Rotea, Marcos F. Pavo López, Álvaro Silgado Herrero,
Ana Hernández Caballero and Carmen Granado García
From Paper to Digital, and Point to Polygon – the Application of GIS in a
National Body of Survey and Record ......................................................677
Peter McKeague and David Cowley
Management of Architectural Heritage Information in BIM and GIS:
State-of-the-art and Future Perspectives ................................................695
G. Saygi and F. Remondin
Going 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
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
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