Search results for "Magnesium"

Luminescence of impyrity and radiation defects in magnesium oxide irradiated by fast neutrons

2009

Abstract The photoluminescence, its excitation and absorption spectra of MgO single crystals are investigated before and after the irradiation with fast neutrons. It is shown that the fast neutron irradiation leads to the formation of two types of centers: the interstitial proton H + i and the Mg(OH) 2 microphase. From the behaviour of the photoluminescence (PL) and its excitation (PLE) spectra we suppose that the photoluminescence band at 730 nm of the MgO crystals belongs to the complex V − OH − Fe 3+ centers, which is transformed during the irradiation with fast neutrons. The obtained results allow assume that the transitionions play an important role in the migration of vacancies and in…

Chemical Transport of Mg and Al in Thin Foils of Nickel Alloys

2000

On the difficulty of assessing the specific surface area of magnesium stearate

2001

Abstract The water content of as-received commercial magnesium stearate batches from animal and vegetable sources have been modified by ageing in humid air at room temperature or by vacuum treatment. The complete adsorption–desorption isotherms of nitrogen and krypton vapours by samples of these as received and modified materials have been measured at liquid nitrogen temperature after standardised vacuum degassing. They are greatly affected by the initial water content of the material. In particular: (a) the BET surface area values computed from the adsorption branch vary widely and is increasing with increasing water content; (b) anomalous hysteresis of varying amplitude is observed in all…

Production of a magnesium ion beam using the MIVOC method

1996

Abstract We report the successful production of multiply charged Mg ion beams at the Jyvaskyla ECRIS using a magnesium compound, magnesocene. The compound was placed in a separate vacuum chamber connected to the second stage of the 6.4 GHz JYFL-ECRIS. From there the vapour of the compound was allowed to diffuse into the source at room temperature. After a brief optimizing procedure the intensity of the 24 Mg 5+ beam was measured to be 11.8 eμA.

On-line yields obtained with the ISOLDE RILIS

2003

The ISOLDE resonance ionization laser ion source (RILIS) allows to ionize efficiently and selectively many metallic elements. In recent yield surveys and on-line experiments with the ISOLDE RILIS we observed 23–34 Mg, 26–34 Al, 98–132 Cd, 149 Tb, 155–177 Yb, 179–200 Tl, 183–215 Pb and 188–218 Bi. The obtained yields are presented together with measured release parameters which allow to extrapolate the release efficiency towards more exotic (short-lived) nuclides of the same elements. 2002 Elsevier Science B.V. All rights reserved.

Ocean acidification impairs vermetid reef recruitment

2014

Vermetids form reefs in sub-tropical and warm-temperate waters that protect coasts from erosion, regulate sediment transport and accumulation, serve as carbon sinks and provide habitat for other species. The gastropods that form these reefs brood encapsulated larvae; they are threatened by rapid environmental changes since their ability to disperse is very limited. We used transplant experiments along a natural CO2 gradient to assess ocean acidification effects on the reef-building gastropod Dendropoma petraeum. We found that although D. petraeum were able to reproduce and brood at elevated levels of CO2, recruitment success was adversely affected. Long-term exposure to acidified conditions…

Management of Toxicity Induced by Anti-EGFR Therapy in Metastatic Colorectal Cancer

2013

Use of anti-epidermal growth factor receptor (anti-EGFR) agents has yielded significant advances in the treatment of patients with metastatic colorectal cancer. In fact these drugs, which include the monoclonal antibodies cetuximab and panitumumab, can be delivered both as a single agent and in combination with chemotherapy, achieving better survival and quality of life and in some cases also resectability of metastases. However, these agents can result in the development of toxicities that are usually different from those observed with chemotherapy alone. For the management of these adverse effects, proper knowledge is mandatory. Skin toxicity is the most frequent adverse effect. Other tox…

Insight into the primary mode of action of TiO2 nanoparticles on Escherichia coli in the dark.

2015

16 pages; International audience; Large-scale production and incorporation of titanium dioxide nanoparticles (NP-TiO2 ) in consumer products leads to their potential release into the environment and raises the question of their toxicity. The bactericidal mechanism of NP-TiO2 under UV light is known to involve oxidative stress due to the generation of reactive oxygen species. In the dark, several studies revealed that NP-TiO2 can exert toxicological effects. However, the mode of action of these nanoparticles is still controversial. In the present study, we used a combination of fluorescent probes to show that NP-TiO2 causes Escherichia coli membrane depolarization and loss of integrity, lead…

Insights into the Maya Blue technology: greenish pellets from the ancient city of La Blanca.

2011

Financial support is gratefully acknowledged from the MEC Projects CTQ2011-28079-CO3-01 and 02 which are also supported with ERDF funds. Research was conducted within the "Grupo de anlisis cientifico de bienes culturales y patrimoniales y estudios de ciencia de la conservacion" Microcluster of the University of Valencia Excellence Campus. The authors would like to thank Dr. Isabel Solana (SCSIE, UV), Dr. Jose Luis Moya Lopez, and Manuel Planes Insausti (Microscopy Service UPV) for their technical support.

Influence of temperature and background electrolyte on the sorption of neptunium(V) on Opalinus Clay

2012

Abstract The temperature dependence of the sorption of 8 μM neptunium(V) on Opalinus Clay (OPA, Mont Terri, Switzerland) was investigated between 40 and 80 °C and compared to previous results for 20 °C. The batch experiments were performed under ambient air conditions in synthetic pore water (pH = 7.6, I = 0.4 M) under variation of the solid-to-liquid ratio between 2 and 20 g/L. Under these conditions the sorption of Np(V) on OPA was found to be an endothermic process as the average distribution coefficient (K d ) increases continuously with increasing temperature from 23 ± 4 L/kg at 40 °C to 678 ± 254 L/kg at 80 °C. In the temperature range of 40-80 °C, the plot of log(K d ) vs. 1/T could …