1,721,053 research outputs found
Studia theodisca – Hölderliniana I
No full textIl numero speciale della rivista documenta il convegno fondativo della sezione italiana della Hölderlin-Gesellschaft (Roma 2103) e integra le relazioni lá tenute con ulteriori studi e recensioni
High-throughput determination of cortisol, cortisone, and melatonin in oral fluid by on-line turbulent flow liquid chromatography interfaced with liquid chromatography/tandem mass spectrometry
No full textRATIONALE:
Cortisol, cortisone, and melatonin (CORTol, CORTone, and MELA, respectively) are hormones related to stress and sleep disorders. Their detection is relevant to epidemiological studies aimed at investigating the effects of circadian cycle disruption. The aim of this study was to develop and evaluate a high-throughput assay for the detection of CORTol, CORTone, and MELA concentrations in non-invasively collected oral fluid samples.
METHODS:
A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to measure levels of CORTol, CORTone, and MELA in oral fluid samples in the presence of deuterated analogs was optimized and validated. A 50 μL aliquot of oral fluid sample, obtained by centrifugation of a chewed swab, was purified using on-line turbulent flow liquid chromatography. Analytes were then separated using C18 reversed-phase chromatography, subjected to positive ionization using an electrospray source, then quantitated using a triple quadrupole mass detector in the selected reaction monitoring mode.
RESULTS:
Limits of quantification and linear dynamic ranges were found to be 0.55 nmol/L, 5.5 nmol/L, and 0.004 nmol/L, and up to 28 nmol/L, 277 nmol/L, and 0.43 nmol/L for CORTol, CORTone, and MELA, respectively. Inter- and intra-run precisions as relative standard deviation values were <5%, and accuracies were within 95-106% of theoretical concentrations. An evaluation of matrix effects showed that the use of deuterated analogs controlled sources of bias. Furthermore, the total analysis time per sample was 13 min, resulting in a throughput of approximately 100 samples/day.
CONCLUSIONS:
To our knowledge, this is the first automated, high-throughput assay for the simultaneous quantification of CORTol, CORTone, and MELA in oral fluid specimens
Determination of terbuthylazine and desethylterbuthylazine in human urine and hair samples by eletrospray ionization-liquid chromatography/triple quadrupole mass spectrometry
No full textTerbuthylazine (TBA) is a widely applied herbicide and an environmental contaminant. Following its use, humans, such as agricultural workers and rural residents, may be exposed. An isotope-dilution liquid chromatography coupled to electrospray-tandem mass spectrometry method for the determination of TBA, and its metabolite desethylterbuthylazine (DET) in human urine and hair was developed and validated. Under the optimised conditions, analytes were extracted from urine using a solid phase cartridge or from hair by sonication in methanol. Analytes were separated using a C18 reversed-phase chromatographic column and quantified, after positive ionization using a heated electrospray source, by a triple quadrupole mass detector in the selected reaction monitoring mode. Validation showed linear dynamic ranges up to 100 μg/L or 5.00 ng/mg hair, inter- and intra-run precisions <7%, and accuracies within 12% of spiked concentrations. Limits of quantification were 0.25 μg/L in urine and 0.01 ng/mg hair for both TBA and DET. Matrix effect evaluation showed that the isotope dilution approach allowed for the control of bias sources. TBA and DET were determined in specimens of agriculture workers exposed to TBA using the validated method. Hair samples contained TBA levels in the low nanogram per milligram range, and urine samples contained DET levels in the low microgram per liter range. Conversely, TBA levels in urine samples and DET levels in hair samples were always below the limit of quantification
Premessa / Vorwort
No full textThe fourth volume of “Studia Hölderliniana”, edited by Marco Castellari and Elena Polledri with the collaboration of Stefano Apostolo, is, as usual, published as a special issue of the international journal “Studia theodisca”. It brings together articles and reviews in both German and Italian on the works and reception of the great German poet Friedrich Hölderlin. This issue, in particular, documents the international conference “Wir sind nichts; was wir suchen, ist alles.” Hölderlin zum 250. Geburtstag, which took place during the Hölderlin Year 2020 at Ca’ Foscari University of Venice. In addition to papers derived from this academic event, further studies addressing key issues in international research are included. The closing section features three reviews of significant recent contributions to the philological, critical, and cultural discourse surrounding Hölderlin.In addition to the aforementioned Apostolo, Castellari, and Polledri, contributors to the issue include Bettina Faber, Marco Fiorletta, Sarah Gaber, Ulrich Gaier, Daniele Goldoni, Martin Huber, Francesco Rossi, Franco Toscani, and Giuseppe Vacca. The volume is dedicated to Luigi Reitani (1959-2021), a great scholar and translator whose scholarly legacy still leads us with a competent and sensitive hand through the ‘fragments of the future” of Hölderlin’s poetry
Studia theodisca – Hölderliniana II (2016)
Full text linkStudia theodisca – Hölderliniana II (2016). The entire volume
Premessa / Vorwort
Full text linkA bilingual foreword by the two volume editors, in which they briefly describe the threefold structure of this publication
Vorwort/Premessa
Full text linkA bilingual foreword by the two volume editors, in which they describe the structure of the publication "Studia theodisca – Hölderliniana III
Premessa / Vorwort
Full text linkA bilingual foreword by the two volume editors, in which they briefly describe the threefold structure of this publication and trace its origins in the founding congress of the Italian section of the “Hölderlin-Gesellschaft”
Dal libro alla scena : Paolo Grassi, Giorgio Strehler und die deutschsprachige Dramatik im Italien der 1940er–50er Jahre
No full textThe contribution investigates the lesser-known phase of the presence of German drama at the Piccolo Teatro di Milano (first decade). Before Giorgio Strehler's Brechtian productions and before the beginning of a real revolution for Italian theatre (which is briefly outlined here), Paolo Grassi and the young director were the protagonists of a sort of preliminary work on German Drama between Vormärz and Expressionism on the page (editions and translations) and on the stage (productions) in the 1940s-50s. As a result of this, Büchner was staged in Italy for the first time in an effective way. In particular, Strehler's work on Büchner's "Dantons Tod" is re-evaluated here in its historical and aesthetic significance
Mercapturic acids as biomarkers for profiling human exposure to environmental and occupational pollutants
Full text linkBackground: Mercapturic acids (MA) are final urinary metabolic products of some environmental and occupational toxicants, formed by the conjugation of glutathione and electrophilic compounds. These electrophilic compounds are believed to be active species able to react with DNA and responsible for the genotoxicity associated with parent compounds. The aim of this work was the development and validation of an analytical assay for the determination of several urinary mercapturic acids to be used as biomarkers for profiling human exposure. Method: An isotope dilution tandem mass spectrometry method, coupled with reversed-phase liquid chromatography, was developed for the analysis of eighteen urinary MA from acrolein (3-HPMA), acrylamide (AAMA, GAMA), acrylonitrile (CEMA, HEMA), benzene (SPMA), 1,3-butadiene (DHBMA, MHBMA), crotonaldehyde (CMEMA, HMPMA), 4-chloronitrobenzene (NANPC), N,N-dimethylformamide (AMCC), ethylene oxide (HEMA), propylene oxide (2-HPMA), styrene (PHEMA1 e 2), toluene (SBMA), methylating (MMA) and ethylating agents (EMA). Samples were prepared by simple filtration after dilution. Calibration curves, sensitivity, accuracy, precision, selectivity, process efficiency, and stability were evaluated for method validation. Moreover an external validation was performed. The assay was applied to the analysis of 46 end of shift urine samples from non-smoker workers of 6 different workplaces: refinery workers, coke oven workers, traffic policemen, rotogravure printing workers, gasoline station attendants, asphalt workers, and workers not occupationally exposed to chemicals. Result: Limits of quantitation ranged from 0.01 to 3.2 μg/L, precision assays yielded optimal values for all compounds, with all RSDs < 10%, and accuracy values ranging from 93.4% to 114.9% of theoretical value. The use of deuterated internal standards was suitable to control for matrix effect. The assay allowed the simultaneous quantitation of urinary mercapturic acids at different ranges of concentration. The external validation exercise was positive for all compounds. The application of the assay to urine samples of workers highlighted differences in mercapturic acid profiles among groups for: CEMA, DHBMA, MHBMA, PHEMA and SPMA, in agreement with the expected patterns of exposure. Conclusion: This high-throughput method is a valid and useful tool for the determination of urinary mercapturic acids, suitable for human biomonitoring of occupational and environmental exposure
- …
