Search results for "Precipitation"
showing 10 items of 826 documents
Optimization of the gravimetric determination method of nickel as dimethylglyoximate for nickel raw materials
1999
The method parameters of an almost one century old method for analyzing nickel as dimethylglyoximate were critically examined for the analysis of nickel raw materials and many of the method parameters were observed to have a significant effect on the Ni recovery. Thus, because the Ni precipitation method parameters vary a lot in analytical literature and also in practice, the obtained Ni results by different methods are not comparable. During this study it was found that the double precipitation worked out perfectly in eliminating the effects of impurity elements. The residual Ni content in the filtrates should also be measured to obtain accurate and precise Ni results. In complexing the im…
Analysis of toxic elements in plastic components for toys. Multi-elemental determination by x-ray fluorescence
1993
Abstract An x-ray fluorescence method is proposed for the multi-elemental determination of toxic elements in plastic articles for children, viz., Sb(III), Ba, Cd, Cr(III), Hg, Pb and As(III). Mineralization is achieved by using molten sodium hydroxide to decompose the organic matrix, with sodium nitrate as auxiliary oxidant. Stable solutions containing the chemical species for analysis are obtained. The species are separated from the solution by (co)precipitation, in a medium of NH+4-NH3 buffer (pH 8.5) with sodium diethyldithiocarbamate, sodium rhodizonate and Fe3+, which acts as a carrier. The precipitates deposited on filter-paper are placed in the x-ray spectrometer in fine layer morpho…
Propagation of precipitation measurement biases into the hydraulic modelling of urban drainage systems – A case study of the Parco D’Orleans sub-urba…
2020
Aim of this study is to evaluate the impact of Precipitation Measurement Biases (PMBs) of tippingbucket rain gauges onto the hydraulic modelling of urban drainage networks. As a case study, the monitored experimental suburban catchment of Parco d’Orleans located in the University Campus of Palermo, Italy and managed since 1987 by the Department of Engineering of the University of Palermo is considered. . Two tipping-bucket rain gauges provide a good spatial coverage of the catchment area and an acoustic level gauge is installed at the outlet of the drainage network for flow mesaurements. Contemporary high temporal resolution rainfall and runoff data series are available between 1993 to 1998…
Effects of precipitation seasonality, irrigation, vegetation cycle and soil type on enhanced weathering – modeling of cropland case studies across fo…
2022
Enhanced weathering (EW) is a promising strategy for carbon sequestration, but several open questions remain regarding the actual rates of dissolution in conditions of natural hydroclimatic variability in comparison to laboratory experiments. In this context, models play a pivotal role, as they allow exploring and predicting EW dynamics under different environmental conditions. Here a comprehensive hydro-biogeochemical model has been applied to four cropland case studies (i.e., Sicily and the Padan plain in Italy and California and Iowa in the USA) characterized by different rainfall seasonality, vegetation (i.e., wheat for Sicily and California and corn for the Padan plain and Iowa), and s…
SUMOylation of Blimp-1 promotes its proteasomal degradation
2011
Abstract B lymphocyte induced maturation protein-1 (Blimp-1) is a transcription repressor of the Krueppel-like family. Blimp-1 plays important roles in developmental processes, such as of germ cells and hair follicle stem cells. In B lymphocytes Blimp-1 orchestrates the terminal differentiation into plasma cells. We discovered that Blimp-1 undergoes SUMOylation by SUMO-1. This SUMOylation is modulated by the SUMO protease SENP1. While Blimp-1 is relatively stable in 293T cells, a fusion with SUMO1 rendered it to rapid proteasomal degradation. Increase in SENP1 activity stabilized Blimp-1, while a decrease promoted its degradation. Our data indicate that SUMOylation of Blimp-1 regulates its …
Chaperone action in the posttranslational topological reorientation of the hepatitis B virus large envelope protein: Implications for translocational…
2003
The large L envelope protein of the hepatitis B virus utilizes a new folding pathway to acquire a dual transmembrane topology in the endoplasmic reticulum (ER). The process involves cotranslational membrane integration and subsequent posttranslational translocation of its preS subdomain into the ER. Here, we demonstrate that the conformational and functional heterogeneity of L depends on the action of molecular chaperones. Using coimmunoprecipitation, we observed specific interactions between L and the cytosolic Hsc70, in conjunction with Hsp40, and between L and the ER-resident BiP in mammalian cells. Complex formation between L and Hsc70 was abolished when preS translocation was artifici…
Identification of ERp29, an endoplasmic reticulum lumenal protein, as a new member of the thyroglobulin folding complex.
2002
Folding and post-translational modification of the thyroid hormone precursor, thyroglobulin (Tg), in the endoplasmic reticulum (ER) of the thyroid epithelial cells is facilitated by several molecular chaperones and folding enzymes, such as BiP, GRP94, calnexin, protein disulfide isomerase, ERp72, and others. They have been shown to associate simultaneously and/or sequentially with Tg in the course of its maturation, thus forming large heterocomplexes in the ER of thyrocytes. Here we present evidence that such complexes include a novel member, an ER-resident lumenal protein, ERp29, which is present in all mammalian tissues with exceptionally high levels of expression in the secretory cells. …
Perturbed interactions of mutant proteolipid protein/DM20 with cholesterol and lipid rafts in oligodendroglia: implications for dysmyelination in spa…
2006
Missense mutations in the humanPLP1gene lead to dysmyelinating diseases with a broad range of clinical severity, ranging from severe Pelizaeus–Merzbacher disease (PMD) to milder spastic paraplegia type 2 (SPG-2). The molecular pathology has been generally attributed to endoplasmic reticulum (ER) retention of misfolded proteolipid protein (PLP) (and its splice isoform DM20) and induction of the unfolded protein response. As opposed to previous studies of heterologous expression systems, we have analyzed PLP/DM20 trafficking in oligodendroglial cells, thereby revealing differences between PMD and SPG-2-associated PLP/DM20 isoforms. PLPA242Vand DM20A242V(jimpy-msdin mice), associated with seve…
The Abundant Tegument Protein pUL25 of Human Cytomegalovirus Prevents Proteasomal Degradation of pUL26 and Supports Its Suppression of ISGylation
2018
The tegument of human cytomegalovirus (HCMV) virions contains proteins that interfere with both the intrinsic and the innate immunity. One protein with a thus far unknown function is pUL25. The deletion of pUL25 in a viral mutant (Towne-ΔUL25) had no impact on the release of virions and subviral dense bodies or on virion morphogenesis. Proteomic analyses showed few alterations in the overall protein composition of extracellular particles. A surprising result, however, was the almost complete absence of pUL26 in virions and dense bodies of Towne-ΔUL25 and a reduction of the large isoform pUL26-p27 in mutant virus-infected cells. pUL26 had been shown to inhibit protein conjugation with the in…
Modeling and numerical simulation of the propagation of pitting corrosion of iron in chlorinated medium : contribution to the evaluation of the durab…
2012
This study deals with the understanding of the mechanisms of pitting corrosion susceptible to occur on carbon steel selected for high level nuclear waste containers. Transport/reaction models have been developed in order to simulate, by finite element method, the propagation of a pit on iron in chlorinated medium. For conservative models, pit is activated by imposing a potential on metal. Thanks to different parametric studies (geometry, environment…) simulations have permitted to classify, by severity order, the factors responsible of the increase or the inhibition of the localized corrosion rate. Otherwise, experiments on occluded (called « lead-in-pencil ») electrodes confirm that confin…