Search results for "Urea"
showing 10 items of 888 documents
Metallic lead recovery from lead-acid battery paste by urea acetate dissolution and cementation on iron
2009
Abstract A suitable hydrometallurgical and environmentally friendly process was studied to replace the currently used practices for recycling lead-acid batteries via smelting. Metallic lead was recovered by cementation from industrial lead sludge solutions of urea acetate (200 to 500 g/L) using different types of metallic iron substrates (nails, shaving or powder) as reducing agents. Under specific operating conditions, up to 99.7% of lead acid battery paste, mainly composed of PbSO4, PbO2 and PbO·PbSO4 species, was converted to metallic lead.. The conversion of the metallic lead and rate of the cementation reaction were strictly dependent on the type of iron substrate used as the reductant…
Growth and macromolecular content of the dimorphic fungus Aureobasidium pullulans and the effect of hydroxyurea and other inhibitors
1988
The growth kinetics and the macromolecular content of the yeast and ethanol-induced hyphal forms of Aureobasidium pullulans were studied. During the morphological transition from yeasts to hyphae, both the protein and RNA content decreased significantly, the mycelial form containing only 76% of the amount of protein in the yeasts, and 38% of the RNA. The DNA was the only component tested whose level increased during the transition. Among several compounds inhibiting macromolecular synthesis, only hydroxyurea showed a remarkable effect on the morphology of A. pullulans, inducing the mycelial morphology. The macromolecular composition of hydroxyurea-treated cultures changed with time in a way…
Influence of DNA Repair on Nonlinear Dose-Responses for Mutation
2013
Recent evidence has challenged the default assumption that all DNA-reactive alkylating agents exhibit a linear dose-response. Emerging evidence suggests that the model alkylating agents methyl- and ethylmethanesulfonate and methylnitrosourea (MNU) and ethylnitrosourea observe a nonlinear dose-response with a no observed genotoxic effect level (NOGEL). Follow-up mechanistic studies are essential to understand the mechanism of cellular tolerance and biological relevance of such NOGELs. MNU is one of the most mutagenic simple alkylators. Therefore, understanding the mechanism of mutation induction, following low-dose MNU treatment, sets precedence for weaker mutagenic alkylating agents. Here, …
Novedades y consideraciones sobre el género Centaurea L. en la flora valenciana
2008
Se realizan algunas reflexiones sobre las especies valencianotarraconenses de Centaurea sect. Willkommia, grupo que actualmente está conformado por seis táxones en dicho territorio. A partir del estudio de numeroso material que cubre la mitad norte de la provincia de Valencia y la totalidad de Castellón, se revisan dichos táxones y se realiza una nueva propuesta en la que se describen dos nuevas especies: C. aguilellae (de las comarcas del centro-norte de Valencia) y C. fabregatii (de las comarcas del centro-este de Castellón). Novelties and considerations on Centaurea L. concerning the Valencian flora (eastern Spain): Data are reported on the Valencian-Tarraconensian (E of Spain) species o…
MEMORIE DAGLI SCAVI PER UN'ARCHEOLOGIA DELLA LETTERATURA IN GESUALDO BUFALINO
2022
The essay reflects on the lexical dissemination of terms belonging to the metaphorical area of 'recovery,' 'rebirth,' and 'rediscovery' in Bufalino's work beginning with Diceria dell'untore, in order to try to demonstrate the legacy of a private experience, the one related to the writing of his dissertation during the years of war and illness, in the transfigured one of literary reworking.
Hapten Synthesis and Polyclonal Antibody-Based Immunoassay Development for the Analysis of Forchlorfenuron in Kiwifruit
2010
High-affinity polyclonal antibodies directed against the synthetic cytokinin forchlorfenuron (CPPU) were produced from three immunizing haptens with equivalent spacer arms located at different positions. A competitive immunoassay was developed with a limit of detection in buffer of 12.42 +/- 3.06 ng/L. In addition, the ability of the produced antibodies to recognize a set of synthetic CPPU analogues was studied. It was evidenced that the linker position had a strong impact on the specificity of the generated polyclonals, which were more sensitive to changes at moieties of the target analyte located furthest from the derivatization site of the immunogen. Finally, matrix effects of gold and g…
NQS-Doped PDMS Solid Sensor: From Water Matrix to Urine Enzymatic Application
2021
The development of in situ analytical devices has gained outstanding scientific interest. A solid sensing membrane composed of 1,2-naphthoquinone-4-sulfonate (NQS) derivatizing reagent embedded into a polymeric polydimethylsiloxane (PDMS) composite was proposed for in situ ammonium (NH4+) and urea (NH2CONH2) analysis in water and urine samples, respectively. Satisfactory strategies were also applied for urease-catalyzed hydrolysis of urea, either in solution or glass-supported urease immobilization. Using diffuse reflectance measurements combined with digital image processing of color intensity (RGB coordinates), qualitative and quantitative analyte detection was assessed after the colorime…
Contents of the Sexual and Reproductive Health Subject in the Undergraduate Nursing Curricula of Spanish Universities: A Cross-Sectional Study
2021
Background: Nursing students must receive adequate training in Sexual and Reproductive Health (SRH), which could allow them to acquire sufficient knowledge to solve the future SRH needs of everyone. In this study, the contents of the SRH subject in the undergraduate nursing curricula of 77 Spanish universities were examined to determine what SRH training nursing students are receiving. Methods: The contents of the SRH subject of all the curricula that were available online were reviewed. The distribution of the contents (topics) in the two areas (reproductive health and sexual health) was analyzed, and the prevalence of each topic was established. It was also determined whether there were d…
Structure of Urea Clusters Confined in AOT Reversed Micelles
2003
The structure of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and that of urea containing AOT reversed micelles has been investigated by small-angle neutron scattering (SANS) and Fourier transform infrared (FT-IR) spectroscopy at different AOT concentrations and urea/AOT molar ratios. For the AOT/n-heptane system, SANS data analysis indicates that AOT molecules form prolate ellipsoidal aggregates, which grow asymmetrically along the major axis upon increasing the surfactant concentration. For the urea/AOT/n-heptane system, the SANS results are consistent with the hypothesis that urea is encapsulated as small-sized ellipsoidal hydrogen-bonded clusters within the hydrophilic micellar core of …
Una Mostra “en plein air” per le Tesi di Laurea degli Studenti del Corso di Ingegneria edile ‐ Architettura della Facoltà di Ingegneria di Palermo
2013
La complessità dei lavori di studio e di ricerca, documentati dalle Tavole esposte nella Mostra di Tesi del Corso di Laurea in Ingegneria edile - Architettura della Facoltà di Ingegneria di Palermo, allarga l’orizzonte “limitato” -attribuito dai più all’Ingegnere Edile “non Architetto”- e lo estende a comprendere le problematiche proprie del fare Architettura a 360°. Le Tavole della Mostra, esposte nella hall d’ingresso dell’Aula Magna della Facoltà di Ingegneria di Palermo in occasione del Decennale del Corso di Laurea in Ingegneria edile – Architettura e pubblicate in questo piccolo catalogo, hanno voluto e vogliono dare testimonianza del “sapere” degli Ingegneri edili - Architetti dell’A…