Search results for " Phase"

Advanced FEM modeling of friction stir welding of Ti6Al4V: Microstructural evolutions

2013

Friction Stir Welding (FSW) is a solid state welding process patented in 1991 by TWI; initially adopted to weld aluminum alloys, is now being successfully used also for high resistant materials. Welding of titanium alloys by traditional fusion welding techniques presents several difficulties due to high material reactivity resulting in bonding with oxygen, hydrogen, and nitrogen with consequent embrittlement of the joint. In this way FSW represents a cost effective and high quality solution. The final mechanical properties of the joints are strictly connected to the microstructural evolutions, in terms of phase change, occurring during the process. In the paper a 3D FEM model of the FSW wel…

Large Scale MOCVD Synthesis of Hollow ReS2 Nanoparticles with Nested Fullerene-Like Structure

2008

The synthesis of ReS2 onionlike nanoparticles by means of a high-temperature MOCVD process starting from Re2(CO)10 and elemental sulfur is reported. The reaction is carried out in a two-step proces...

Selective Synthesis of Hollow and Filled Fullerene-like (IF) WS2 Nanoparticles via Metal–Organic Chemical Vapor Deposition

2007

The synthesis of WS2 onion-like nanoparticles by means of a high-temperature metal–organic chemical vapor deposition (MOCVD) process starting from W(CO)6 and elemental sulfur is reported. The react...

ChemInform Abstract: Large Scale MOCVD Synthesis of Hollow ReS2Nanoparticles with Nested Fullerene-Like Structure.

2008

Biomonitoring of Enniatin B1 and Its Phase I Metabolites in Human Urine: First Large-Scale Study

2020

Enniatins (Enns) are mycotoxins produced by Fusarium spp. which are a fungus widely spread throughout cereals and cereal-based products. Among all the identified enniatins, Enn B1 stands as one of the most prevalent analogues in cereals in Europe. Hence, the aim of this study was to evaluate for the first time the presence of Enn B1 and its phase I metabolites in 300 human urine samples using an ultrahigh-performance liquid chromatography high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) methodology. Enn B1 was detected in 94.3% of samples ranging from 0.007 to 0.429 ng/mL (mean value: 0.065 ng/mL). In accordance with previous in vitro and in vivo analysis, hydroxylated metabolites …

Liquid chromatographic determination of toxigenic secondary metabolites produced by Fusarium strains.

2002

Various liquid chromatographic methods used in the analysis of mycotoxins (zearalenone, trichothecenes and fumonisins) produced by Fusarium species were compared in this work. The results demonstrate the suitability of modern clean-up procedures employing multifunctional MycoSep and immunoaffinity columns although these methods are more expensive than conventional methodologies for clean-up. HPLC with both fluorescence and photodiode array detection is a suitable technique for the analysis of toxic secondary metabolites produced by Fusarium species; different derivatisation strategies have been studied to improve the sensitivity of the technique because of the low concentration of these met…

As2O3-induced oxidative stress and cycle progression in a human intestinal epithelial cell line (Caco-2)

2007

Foods and drinking water are the main routes for human exposure to inorganic arsenic, the intestinal epithelium being the first barrier against such exogenous toxicants. The present study evaluates the effect of As(III) (0.5-25 microM) upon Caco-2 cells as an intestinal epithelia model. Cell viability, intracellular formation of reactive oxygen species (ROS), mitochondrial membrane potential (Deltapsim) changes, and cell cycle distribution in exposed cultures were evaluated. The intracellular production of ROS was seen to increase in a non-dose dependent manner at all concentrations tested, with impairment of cell mitochondrial enzyme function secondary to a loss of Deltapsim. Concentration…

CD133 Expression Is Not Synonymous to Immunoreactivity for AC133 and Fluctuates throughout the Cell Cycle in Glioma Stem-Like Cells.

2015

A transmembrane protein CD133 has been implicated as a marker of stem-like glioma cells and predictor for therapeutic response in malignant brain tumours. CD133 expression is commonly evaluated by using antibodies specific for the AC133 epitope located in one of the extracellular domains of membrane-bound CD133. There is conflicting evidence regarding the significance of the AC133 epitope as a marker for identifying stem-like glioma cells and predicting the degree of malignancy in glioma cells. The reasons for discrepant results between different studies addressing the role of CD133/AC133 in gliomas are unclear. A possible source for controversies about CD133/AC133 is the widespread assumpt…

Ofd1, a Human Disease Gene, Regulates the Length and Distal Structure of Centrioles

2010

SUMMARYCentrosomes and their component centrioles represent the principal microtubule organizing centers of animal cells. Here we show that the gene underlying Orofaciodigital Syndrome 1, Ofd1, is a component of the distal centriole that controls centriole length. In the absence of Ofd1, distal regions of centrioles, but not procentrioles, elongate abnormally. These long centrioles are structurally similar to normal centrioles, but contain destabilized microtubules with abnormal post-translational modifications. Ofd1 is also important for centriole distal appendage formation and centriolar recruitment of the intraflagellar transport protein Ift88. To model OFD1 Syndrome in embryonic stem ce…

Escherichia coli cytolethal distending toxin blocks the HeLa cell cycle at the G2/M transition by preventing cdc2 protein kinase dephosphorylation an…

1997

Cytolethal distending toxins (CDT) constitute an emerging heterogeneous family of bacterial toxins whose common biological property is to inhibit the proliferation of cells in culture by blocking their cycle at G2/M phase. In this study, we investigated the molecular mechanisms underlying the block caused by CDT from Escherichia coli on synchronized HeLa cell cultures. To this end, we studied specifically the behavior of the two subunits of the complex that determines entry into mitosis, i.e., cyclin B1, the regulatory unit, and cdc2 protein kinase, the catalytic unit. We thus demonstrate that CDT causes cell accumulation in G2 and not in M, that it does not slow the progression of cells th…