Search results for "Metals"

Short‐term hypoxia promotes vascularization in co‐culture system consisting of primary human osteoblasts and outgrowth endothelial cells

2019

Prevascularization of tissue constructs before implantation has been developed as a novel and promising concept for successful implantation. Since hypoxia might induce angiogenesis, we have investigated the effects of hypoxic treatment on vascularization by using co-cultures of primary human osteoblasts (POBs) and outgrowth endothelial cells. Our results show that: (a) repeated short-term hypoxia (2% O2 for 8 hr), not long-term hypoxia (2% O2 for 24 hr), over 1 or 2 weeks, significantly enhances microvessel formation in co-cultures; (b) sustained hypoxia, not short-term or long-term hypoxia, causes cytotoxicity in mono- and co-cultures; (c) the expression of some angiogenic and inflammatory…

A logarithmic multi-parameter model using gas sensor main and cross sensitivities to estimate gas concentrations in a gas mixture for SnO2 gas sensors

2007

Abstract In a metal-oxide semiconductor gas sensor, the sensitivity of the metal-oxide resistance to concentrations of reducing gases in the surrounding atmosphere is known to be related to adsorption and desorption of gas on the redox reactions between the gas and oxygen. Changes in the electric conductance due to these reactions were measured for tin dioxide semiconductor gas sensors. In this study, we propose a model of gas sensor responding behaviour using a relationship between sensor conductance and gas concentrations in a mixture. A least-squares method fit of measured data was applied to determining the values of coefficients. The proposed method uses main and cross sensitivities th…

Preparation and characterization of sodium iron titanate ion exchanger and its application in heavy metal removal from waste waters.

2006

Abstract The ion exchange properties of sodium iron titanates, namely, NaFeTiO4, Na2Fe2Ti6O16 and iron-doped sodium nonatitanate were investigated. Conventional solid state and sol–gel methods were used in the synthesis of the sodium iron titanates. Structural characterization of the materials was performed with powder X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and with inductively coupled plasma optical emission spectrometry (ICP-OES). Based on TG analyses, the novel iron-doped sodium nonatitanate was proven to be a member of the layered titanate family. The different sodium iron titanates were compa…

Formation of a micropatterned titania photocatalyst by microcontact printed silicatein on gold surfaces

2012

The enzyme silicatein has been bioengineered to carry a thiol-bearing Au-affinity tag (Cys-tag) for direct immobilization on gold carriers in shortest time without the need for prior surface functionalization. Through microcontact printing, defined silicatein micropatterns were created on gold surfaces, facilitating the subsequent enzymatically controlled synthesis of photocatalytically active TiO(2).

Exposure assessment of a burning ground for chemical ammunition on the Great War battlefields of Verdun

2007

The destruction of arsenical shells from the 1914/18 war in the vicinity of Verdun (France) during the 1920s resulted in a locally limited but severe soil contamination by arsenic and heavy metals. At the study site, the main part of the contaminant inventory occurs in the upper 20 cm of the topsoil which is essentially composed of combustion residues. Besides, some Cu (cmax.=16,877 mg/kg) and Pb (cmax.=26,398 mg/kg) in this layer, As (cmax.=175,907 mg/kg) and Zn (cmax.=133,237 mg/kg) were detected in very high concentrations. The mobilities of Cu, Mn, Pb and Zn in the soil system were derived from ammonium nitrate eluates. They are strongly influenced by the soil pH and can be described by…

Estimation of interfacial fracture toughness based on progressive edge delamination of a thin transparent coating on a polymer substrate

2010

Evaluation of interfacial toughness of sub-micron-thickness layers deposited on a ductile substrate is a challenging task which has motivated different experimental approaches Fragmentation testing was used in the present study as a means of interface characterization of a silicon-nitride-coated polyimide substrate. During the test, after an initial rapid segmentation-cracking phase, the coating fragments developed edge delaminations which propagated in a stable manner with further increase in the applied strain The debonding process was modelled by the finite element method Incorporating a cohesive zone at the front of the interfacial crack The edge cracks were found to be dominated by mod…

Comparison of metals and essential trace elements levels between Autistic Spectrum Disorders cases and their sibs in Sicily (southern Italy)

2016

Introduction: A role of metals exposure and essential trace element deficiency in Autistic Spectrum Disorders (ASD) etiology has been suggested by epidemiologic studies, but conclusive evidence on this topic is still lacking and controversial. We compared metals and essential trace element levels between cases both with their brothers and healthy children. Methods: The diagnosis of ASD were performed by ADOS and ADI-R according to DSM IV (Diagnostic and Statistical Manual of Mental Disorders) criteria. Hair samples were collected from cases and sibs by single cutting from the occipital region. The samples were cut to lengths of about 1.5–2 cm using clean stainless steel scissors. Approximat…

Geochemical comparison of natural and anthropogenic metal fluxes in extreme environments: Mt. Etna volcano (Italy) and Šalek Valley (Slovenia)

2009

Geochemical comparison between some metals (As, Cd, Cu, Pb, Se, V, Zn) emissions from an active volcano (Mt. Etna) and a highly industrialized area (Šalek Valley) showed some interesting similarities: in general, most of the elements emitted into the atmosphere do not return to the Earth’s surface and are therefore dispersed into the environment. Exceptions for Šalek Valley are Cd, which probably derives in large part from rock leaching, and in part As and Pb, which fall mostly as ash. Also, Etna’s emissions are richer in Cd and Cu, whereas industrial emissions at Šalek Valley are richer in V and Zn. All other metals have similar fluxes in the two types of emissions.

Volcanic soil-rainwater interaction at Mount Etna, Sicily. Preliminary Results

2008

A redox-sensitive nanofluidic diode based on nicotinamide-modified asymmetric nanopores

2017

[EN] We demonstrate a redox-sensitive nanofluidic diode whose ion rectification is modulated by the oxidation and reduction of chemical moieties incorporated on its surface. To achieve this goal, we have first synthesized the chemical compounds 1-(4-aminobutyl)-3-carbamoylpyridin-1-ium (Nic-BuNH2) and 3-carbamoyl-1-(2,4-dinitrophenyl)pyridinium (Nic-DNP). Then, the surface of track-etched single asymmetric nanopores is decorated with the redox-sensitive Nic-BuNH2 and Nic-DNP molecules using carbodiimide coupling chemistry and Zincke reaction, respectively. The success of the modification reactions is monitored through the changes in the current¿voltage (I¿V) curves prior to and after pore f…