Search results for "urea"
showing 10 items of 888 documents
Determination of cow's milk and ripening time in nonbovine cheese by capillary electrophoresis of the ethanol-water protein fraction
2000
A novel method is reported for analyzing adulteration of goat and ewe cheeses with cow's milk: capillary zone electrophoresis (CZE) in isoelectric, acidic buffers (50 mM imino diacetic acid, IDA, pH = pI 2.3). The cheese samples were extracted with a 20:80 v/v ethanol-water mixture in presence of 3 M urea and 1% beta-mercaptoethanol for 1 h. After centrifugation and lipid extraction, the samples were dissolved in 50 mM IDA, 6 M urea and 0.5% hydroxyethyl cellulose and analyzed by CZE at 700 V/cm. A total of 18 characteristic peaks were resolved among the three types of cheeses and 18 variables were defined as their respective areas. There was excellent similarity among the electrophoretic p…
A Microplate Assay for DNA Damage Determination (Fast Micromethod)in Cell Suspensions and Solid Tissues
1999
Abstract A rapid and convenient procedure for DNA damage determination in cell suspensions and solid tissues on single microplates was developed. The procedure is based on the ability of commercially available fluorochromes to interact preferentially with dsDNA in the presence of ssDNA, RNA, and proteins at high pH (>12.0), thus allowing direct measurements of DNA denaturation without sample handling or stepwise DNA separations. The method includes a simple and rapid 40-min sample lysis in the presence of EDTA, SDS, and high urea concentration at pH 10, followed by time-dependent DNA denaturation at pH 12.4 after NaOH addition. The time course and the extent of DNA denaturation is followed …
Determination of Urea Pesticide Residues in Vegetable, Soil, and Water Samples
2003
The main physico-chemical, toxicological, and environmental properties of urea pesticides are summarized. General characteristics of analytical methods for residues of phenylurea herbicides (PUHs), sulfonylurea herbicides (SUHs), and Benzoylurea insecticides (BUIs) in crops, soil, and water samples, employed in the last 5 years are reviewed. Provided it is information about liquid-liquid and solid-phase extraction of the samples and clean-up steps. The applications of gas chromatography (GC), liquid chromatography (LC), and capillary electrophoresis (CE) techniques in the analysis of these compounds are exposed in tabular form and commented on. Sensitivity and instrument conditions of liqui…
FT-IR investigation of the urea state in lecithin and sodium bis(2-ethylhexyl)phosphate reversed micelles
2003
Abstract FT-IR spectra of urea/lecithin/CCl4 and urea/sodium bis(2-ethylhexyl) phosphate (NaDEHP)/CCl4 systems as a function of the urea-to-surfactant molar ratio (Rurea) at a fixed surfactant concentration (0.1 mol kg−1) have been recorded at 25 °C. Analysis of the absorption spectra leads the to hypothesis that urea is confined within the hydrophilic micellar core of lecithin and NaDEHP reversed micelles. The encapsulation of urea involves some changes of the urea NH stretching band with respect to that of the pure solid urea, attributable to confinement effects. The stretching modes of the surfactant head group are affected by the presence of urea, indicating specific urea-surfactant hea…
Nephrotoxic and hepatotoxic effects of chromium compounds in rats
1986
The nephrotoxic, hepatotoxic and cardiotoxic actions of hexavalent chromium compounds, as well as their effects on lung, blood and circulation may contribute to the fatal outcome of chromium intoxication. Although trivalent chromium have been regarded as relatively biologically inert, there are a few salts of chromium III that have been found to be carcinogenic when inhaled, ingested or brought in contact with the tissues. Sensitive persons and industry workers have been subjects of dermatitis, respiratory tract injuries and digestive ulcers due to chromium compounds. In this work, the authors have studied the effect of trivalent and hexavalent chromium compounds on rats measuring the trans…
Thiourea Organocatalysts as Emerging Chiral Pollutants: En Route to Porphyrin-Based (Chir)Optical Sensing
2021
Environmental pollution with chiral organic compounds is an emerging problem requiring innovative sensing methods. Amino-functionalized thioureas, such as 2-(dimethylamino)cyclohexyl-(3,5-bis(trifluoromethyl)phenyl)thiourea (Takemoto’s catalyst), are widely used organocatalysts with virtually unknown environmental safety data. Ecotoxicity studies based on the Vibrio fischeri luminescence inhibition test reveal significant toxicity of Takemoto’s catalyst (EC50 = 7.9 mg/L) and its NH2-substituted analog (EC50 = 7.2–7.4 mg/L). The observed toxic effect was pronounced by the influence of the trifluoromethyl moiety. En route to the porphyrin-based chemosensing of Takemoto-type thioureas, their s…
Cittadinizzazione e policy migratorie nella Sicilia occidentale : Progettare servizi innovativi rafforzando le Pubbliche Amministrazioni in attuazion…
2021
L’accesso ai servizi della pubblica amministrazione è spesso, per la popolazione migrante, un cercare la chiave giusta fra un numero spropositato di chiavistelli. Evidenziare come l’inserimento di alcuni servizi innovativi, fra i quali gli sportelli Mi.Main (Migration Mainstreaming) progettati e implementati da giovani laureati all’interno degli uffici della P.A., abbia di fatto favorito processi di “cittadinizzazione”, è stato lo scopo di questo volume. Preliminari ad ogni processo di inclusione sono infatti gli “atti di cittadinanza” che attraversano e ancorano l’universalità dei diritti umani al riconoscimento dei bisogni e delle priorità della persona. Questo volume, descrive come due t…
Liquid chromatography/atmospheric pressure chemical ionization-mass spectrometric analysis of benzoylurea insecticides in citrus fruits.
2000
A liquid chromatography (LC) method for the quantitative determination of three benzoylurea insecticide residues (diflubenzuron, flufenoxuron and hexaflumuron) in citrus fruits is described. Residues were successfully separated on a C18 column by methanol/water gradient elution. Detection was by negative-ion, selected-ion monitoring atmospheric pressure chemical ionization-mass spectrometry (APCI-MS); the main ions were [M - H]-, and the secondary fragment ions were [M - H - HF]-. Useful confirmatory information can thus be obtained at low extraction voltages from losses of HF. Detection limits for standard solutions were 10 fg injected and good linearity and reproducibility were obtained. …
The necessary integration between public management approaches and democratic participatory processes. The case of #ontinyentparticipa
2016
Este artículo tiene por objeto el estudio de #OntinyentParticipa, un proceso político innovador enmarcado en los presupuestos participativos de la localidad valenciana de Ontinyent (España). Describiremos el dispositivo y su contextualización, y analizaremos el papel desempeñado por colectivos, movimientos vecinales y asociaciones implicadas. Además, se tendrá en cuenta la intervención de la administración pública como actor principal del proceso participativo. Para abordar las relaciones entre ciudadanía, Administración y sus enfoques teóricos, se utilizará la tradición del republicanismo contemporáneo con su énfasis en consolidar una democracia más participativa e inclusiva. This article …
Sobre la ?normalidad? de Auschwitz
2020
Resumen: Partiendo de la hipótesis, avanzada por Horkheimer y Adorno, de que Auschwitz era una posibilidad inscrita en la racionalidad instrumental de la civiliza- ción moderna, el artículo analiza algunos mecanismos de la estructura de empresa heredada del industrialismo que pudieron contribuir a ‘normalizar’ lo anormal en el Holocausto nazi. Esta argumentación se desarrolla mediante la articulación de la concepción weberiana de la burocracia moderna con la teoría de la moral de colaboración de Günther Anders.
 Abstract: Starting from the hypothesis, advanced by Horkheimer and Adorno, that Auschwitz was a possibility inscribed in the instrumental rationality of modern civilization, th…