Search results for "Magnesium"

Halogenomercury Salts of Sterically Crowded Triazenides - Convenient Starting Materials for Redox-Transmetallation Reactions

2010

Diaryl-substituted triazenides Ar(Ar′)N3HgX [Ar/Ar′ = Dmp/Mph, X = Cl (2a), Br (3a), I (4a); Ar/Ar′ = Dmp/Tph, X = Cl (2b), I (4b) with Mph = 2-MesC6H4, Mes = 2,4,6-Me3C6H2, Tph = 2′,4′,6′-triisopropylbiphenyl-2-yl and Dmp = 2,6-Mes2C6H3] were synthesized by salt-metathesis reactions in ethyl ether from the readily available starting materials Ar(Ar′)N3Li and HgX2. These compounds may be used for redox-transmetallation reactions with rare-earth or alkaline earth metals. Thus, reaction of 4b or 2b with magnesium or ytterbium in tetrahydrofuran afforded the triazenides Dmp(Tph)N3MX(thf) (5b: M = Mg, X = I; 6b: M = Yb, X = Cl) in good yield. All new compounds were characterized by melting poin…

Partial least squares modelization of energy dispersive X-ray fluorescence.

2019

As a proof of concept, a green methodology has been developed for the energy dispersive X-ray fluorescence (ED-XRF) determination of calcium, potassium, iron, magnesium, aluminum, chromium, strontium, phosphorus and nickel in the peel of untreated kaki fruit (Diospyros kaki. L) samples. ED-XRF spectra of fifty-six kakis purchased in the local area of LLombay (Valencia) were obtained directly from samples without any previous treatment and without sample damage just after cleaning the fruit with distilled water. Inductively Couple Plasma Optical Emission Spectrometry (ICP-OES) was used as a reference method to determine the mineral elements after microwave assisted acid digestion. XRF spectr…

Reproducibility of trace element time-series (Na/Ca, Mg/Ca, Mn/Ca, Sr/Ca, and Ba/Ca) within and between specimens of the bivalve Arctica islandica – …

2017

Abstract Trace element time-series in bivalve mollusk shells and other (biogenic) materials can potentially serve as environmental proxies. Yet, the applicability of element-to-calcium ratios is often challenging, because non-environmental factors such as vital effects distort or mask environmental signals. If a trace element time-series is driven by an environmental factor, it should be reproducible within and between coeval specimens of the same species. In the present study, we tested whether time-series of trace element-to-calcium ratios can be reproduced within and between coeval specimens of the bivalve Arctica islandica and thus whether an external signal is encoded in the temporal v…

Etude expérimentale de l'incorporation du strontium et du magnésium dans les valves d'un ostracode d'eau douce, Herpetocypris brevicaudata (Crustacea…

1997

Resume L'etude geochimique des valves adultes et juveniles (stade 8) d'Herpetocypris brevicaudata, calcifiees en laboratoire, dans une eau portee a quatre temperatures maintenues constantes (12,4; 14,6; 19,8; 23,3 °C), a mis en evidence l'influence du processus de calcification sur l'incorporation du strontium et du magnesium, et a montre que la temperature de l'eau ne modifie pas la teneur en Mg des valves d'H. brevicaudata. Les coefficients de partition D(Sr) et D(Mg) sont determines pour la premiere fois pour cette espece: adulte: D(Sr) = 0,195 ± 0,013 et D(Mg) = 0,0171 ± 0,0018; juvenile: D(Sr) = 0,198 ± 0,009 et D(Mg) = 0,0208 ± 0,0008.

THERAPEUTIC EFFICACY OF MAGNESIUM VALPROATE IN SUCCINIC SEMIALDEHYDE DEHYDROGENASE DEFICIENCY

2012

Succinic semialdehyde dehydrogenase deficiency (SSADHD or gammahydroxybutyric aciduria), a disorder of γ-aminobutyric acid (GABA) metabolism, manifests as a slowly progressive or static encephalopathy. The latter encompasses prominent cognitive dysfunction, neuropsychiatric morbidity and epilepsy.We report safe and effective treatment with MgVPA in an adolescent female with SSADHD and seizures refractory to a broad spectrum of antiepileptics. MgVPA therapy (20 mg/Kg/day) was introduced at 7 years based upon behavioural difficulties and EEG alterations without adverse effects. Therapy was halted at age 13 years, and reintroduced at 14 years, due to new onset complex partial seizures. EEG dem…

Microwave Response of Coaxial Cavities Made of Bulk Magnesium Diboride

2014

We report on the microwave (mw) properties of coaxial cavities built by using bulk MgB2 superconductor prepared by reactive liquid Mg infiltration technology. We have assembled a homogeneous cavity, by using an outer MgB2 cylinder and an inner MgB2 rod, and a hybrid cavity by using an outer copper cylinder and the same MgB2 rod as inner conductor. By the analysis of the resonance curves, in the different resonant modes, we have determined the microwave surface resistance, Rs, of the MgB2 materials as a function of the temperature and the frequency, in the absence of DC magnetic fields. At T = 4.2 K and f = 2.5 GHz, by a mw pulsed technique, we have determined the quality factor of the homog…

Superconducting Microwave Cavity Made of Bulk MgB2

2006

We report the successful manufacture and characterization of a microwave resonant cylindrical cavity made of bulk MgB2 superconductor (Tc = 38.5 K), which has been produced by the Reactive Liquid Mg Infiltration technique. The quality factor of the cavity for the TE011 mode, resonating at 9.79 GHz, has been measured as a function of the temperature. At T = 4.2 K, the unloaded quality factor is 2.2x10^5; it remains of the order of 10^5 up to T ~ 30 K. We discuss the potential performance improvements of microwave cavities built from bulk MgB2 materials produced by reactive liquid Mg infiltration.

Effects of Weak Links in the Nonlinear Microwave Response of MgB2 Superconductor

2006

We report experimental results of second-harmonic (SH) response at microwave frequency in several ceramic MgB2 samples, prepared by different methods. The SH signal has been investigated as a function of the temperature and DC magnetic field. The investigation has been carried out at low magnetic fields, where nonlinear processes arising from motion of Abrikosov fluxons are ineffective. We show that the low-temperature SH emission is ascribable to processes involving weak links. Comparison among the peculiarities of the SH signal radiated by the different samples shows that the presence of weak links strongly depends on the sample preparation method, as well as the purity and morphology of …

The Influence of Surface Treatment on the Kinetic of Growth of Anodic Films on Magnesium in Alkaline Solution

2010

Isolated in-vitro perfusion of pig hearts obtained from the abattoir: an alternative to animal experiments?

1994

Isolated pig hearts (German farm pigs) were characterized after global in-vivo ischaemia as a potential alternative to in-vivo animal studies. Hearts were harvested from adult farm swine at the abattoir 10.3 +/- 2.1 min after incision of the carotid artery. They were immediately perfused and thereafter stored in ice-cold cardioplegic (St Thomas's) solution. After 38 +/- 3 min, retrograde perfusion was started with oxygenated pig blood (37 degrees C; 5000 U Heparin.l-1; pH 7.38 +/- 0.1; 11 mmol glucose.l-1) at a flow rate of 85 ml.min-1 100 g-1 wet weight (gww-1) for 30 min (n = 10). Additionally, shortly after obtaining the hearts, ATP and CP content were measured by enzymatic tests in 10 p…