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21.
Testosterone metabolism revisited: discovery of new metabolites 总被引:1,自引:0,他引:1
Oscar J. Pozo Josep Marcos Rosa Ventura Andreu Fabregat Jordi Segura 《Analytical and bioanalytical chemistry》2010,398(4):1759-1770
The metabolism of testosterone is revisited. Four previously unreported metabolites were detected in urine after hydrolysis
with KOH using a liquid chromatography–tandem mass spectrometry method and precursor ion scan mode. The metabolites were characterized
by a product ion scan obtained with accurate mass measurements. Androsta-4,6-dien-3,17-dione, androsta-1,4-dien-3,17-dione,
17-hydroxy-androsta-4,6-dien-3-one and 15-androsten-3,17-dione were proposed as feasible structures for these metabolites
on the basis of the mass spectrometry data. The proposed structures were confirmed by analysis of synthetic reference compounds.
Only 15-androsten-3,17-dione could not be confirmed, owing to the lack of a commercially available standard. That all four
compounds are testosterone metabolites was confirmed by the qualitative analysis of several urine samples collected before
and after administration of testosterone undecanoate. The metabolite androsta-1,4-dien-3,17-dione has a structure analogous
to that of the exogenous anabolic steroid boldenone. Specific transitions for boldenone and its metabolite 17β-hydroxy-5β-androst-1-en-3-one
were also monitored. Both compounds were also detected after KOH treatment, suggesting that this metabolic pathway is involved
in the endogenous detection of boldenone previously reported by several authors. 相似文献
22.
Fuensanta Andreu Vicent Caselles Jose M. Mazón Salvador Moll 《Mathematische Annalen》2010,347(1):135-199
We prove existence and uniqueness of entropy solutions for the nonhomogeneous Dirichlet problem associated to the relativistic
heat equation. 相似文献
23.
Ohne ZusammenfassungHerrn Prof. Dr. Ing. Fritz Feigl zum 70. Geburtstag gewidmet. 相似文献
24.
In the classical topological context, Dellacherie [10] has given a non-linear version of Hunt's theorem characterizing the proper kernels verifying the complete maximum principle as those closing a submarkovian resolvent. In this paper we study the relation between this non-linear version of Hunt's theorem and T-accretivity. 相似文献
25.
Andreu Presa Rosa F. Brissos Ana Belén Caballero Ivana Borilovic Dr. Luís Korrodi‐Gregório Prof. Ricardo Pérez‐Tomás Dr. Olivier Roubeau Prof. Patrick Gamez 《Angewandte Chemie (International ed. in English)》2015,54(15):4561-4565
The photoactivation of potential anticancer metal complexes is a hot topic of current research as it may lead to the development of more selective drugs. Photoactivated chemotherapy (PACT) with coordination compounds is usually based on a (photo)chemical reaction taking place at the metal center. Herein, a new strategy is exploited that consists of “photomodifying” a ligand coordinated to metal ions. Platinum(II) complexes from photoswitchable 1,2‐dithienylethene‐containing ligands have been prepared, which exhibit two interconvertible photoisomeric forms that present distinct DNA‐interacting properties and cytotoxic behaviors. 相似文献
26.
27.
Mauro Epifani Elisabetta Comini Guido Faglia Jordi Arbiol Teresa Andreu Giovanni Pace Pietro Siciliano Joan R. Morante 《Journal of Sol-Gel Science and Technology》2011,60(3):254-259
A titanium chloromethoxide solution was prepared by reacting TiCl4 with methanol, followed by water addition. The starting solutions were characterized by Fourier Transform Infrared (FTIR) spectroscopy, evidencing that the in situ generated water results in early hydrolysis of the chloroalkoxide. The solution was reacted with molten dodecylamine at room temperature, obtaining a white slurry of amorphous titania nanoparticles. Stable, redispersible TiO2 nanocrystals could be prepared by subsequent solvothermal treatment in oleic acid at 250???C. The use of oleic acid was essential for obtaining crystalline structures, while other surfactants prevented crystallization. The nanocrystals were characterized by X-ray Diffraction and Transmission Electron Microscopy, confirming the formation of anatase TiO2 nanocrystals with a mean size of 3.3?nm. The TiO2 nanocrystals were used for fabricating gas-sensing devices, which were tested towards ethanol vapors. The initial small size of the nanocrystals, and the limited size growth during the high-temperature sensor operation, result in remarkable sensing performances if compared with bulk titania sensors. 相似文献
28.
An efficient synthetic method for 3-aryl-5-dichloromethyl-2-isoxazolines has been established. Reactions between anhydrous chloral and acetophenones in hot acetic acid lead to 1-aryl-4,4,4-trichloro-3-hydroxybutan-1-ones (chloralacetophenones), which provided 1-aryl-4,4-dichlorobut-3-en-1-ones (2,2-dichlorovinylacetophenones) by dehydration and subsequent electrochemical reduction. These β,γ-unsaturated enones reacted with hydroxylamine yielding oxime intermediates whose treatment with aqueous sodium hydroxide gave novel 3-aryl-5-dichloromethyl-2-isoxazolines in fair to high yields. The molecular structure of a member of this family of compounds, 5-dichoromethy1-3-(4-methoxyphenyl)-2-isoxazoline, was determined by X-ray crystallography. 相似文献
29.
In this paper we study the homogeneous relativistic heat equation (HRHE) obtained as asymptotic limit of the so-called relativistic
heat equation (RHE) when the kinematic viscosity ν → ∞. These equations were introduced in the theory of radiation hydrodynamics
to guarantee a bounded speed of propagation of radiating energy. We shall prove that this is indeed true, and we shall construct
some explicit solutions of the HRHE exhibiting fronts propagating at light speed. 相似文献
30.
Jaume Casabó Andreu Solans Carmen Diaz Joan Ribas Alexandre Seguí Montserrat Corbella 《Transition Metal Chemistry》1985,10(4):128-130
Summary Mixed difluoro(diamine)(diamme)chromium(III) complexes have been synthesized with ethylenediamine (en), 1,3 propanediamine(tn) and 1,2-cyclohexanediamine(chxn):trans-[CrF2(aa)(bb)]Br (aa=en, bb=tn; aa=tn, bb= chxn) andcis-[CrF2(aa)(bb)]Br (aa=en, bb=chxn). The corresponding fluoroaqua(diamine) (diamine)chromium(III) complexes have been prepared by acid hydrolysis as perchlorate or iodide salts. All have been characterized by chemical analysis, electronic and i.r. spectra and conductivity measurements. 相似文献