Search results for "actin"
showing 10 items of 1375 documents
Exploring the High-Temperature Frontier in Molecular Nanomagnets: From Lanthanides to Actinides.
2019
Molecular nanomagnets based on mononuclear metal complexes, also known as single-ion magnets (SIMs), are crossing challenging boundaries in molecular magnetism. From an experimental point of view, this class of magnetic molecules has expanded from lanthanoid complexes to both d-transition metal and actinoid complexes. From a theoretical point of view, more and more improved models have been developed, and we are now able not only to calculate the electronic structure of these systems on the basis of their molecular structures but also to unveil the role of vibrations in the magnetic relaxation processes, at least for lanthanoid and d-transition metal SIMs. This knowledge has allowed us to o…
Dendrimer-coated magnetic particles for radionuclide separation
2005
Magnetic particles were synthesised for radionuclide removal from nuclear wastes by magnetic separation. Dendrimers with terminal amino groups attached to the particle surface were used to bind chelating groups for lanthanides and actinides. This led to a 50–400-fold increase of the distribution coefficients for europium and americium in comparison to the reference particles without the dendrimers. Back-extraction studies have demonstrated the possibility of multiple particle recycling.
Narrow rim CMPO/adamantylcalix[4]arenes for the extraction of lanthanides and actinides
2011
Abstract Six p-(1-adamantyl)calix[4]arenes 7, 8 with four differently attached diphenyl-carbamoylmethylphosphine oxide (CMPO) functions at the narrow rim were synthesized. This series was extended by adamantylcalix[4]arenes with two CMPO and two ester, acid or (diethylphosphono)acetylamino groups. Structures of new compounds were proved by NMR, mass-spectrometry and a single-crystal X-ray analysis for the intermediate di-phthalimide 103. The extraction studies towards selected lanthanides and thorium showed that the ligands 7 surpassed the corresponding p-H, p-tert-butyl and p-tert-octyl analogues 3–5 in lanthanide extraction while thorium was extracted with the same or lesser extent. For t…
Preparation of targets by electrodeposition for heavy element studies
2004
Abstract For heavy element studies at GSI, lanthanide and actinide targets have been prepared by molecular plating. The deposition occurs from an isopropanolic solution at 1000–1200 V with current densities of a few mA/cm 2 . Several lanthanide targets have been prepared for test experiments. With nat Gd deposited on a 10 μm thick Be backing foil a target density of 1100 μg/cm 2 could be achieved. Gd-targets were used for the production of α-emitting isotopes of Os, the homologue of hassium (Hs; Z =108), in order to develop a chemical separation procedure for Hs. 248 Cm targets with densities up to 730 μg/cm 2 have been produced for recent experiments to investigate the chemical behaviour o…
Preparation of targets for the gas-filled recoil separator TASCA by electrochemical deposition and design of the TASCA target wheel assembly
2008
Abstract The Transactinide Separator and Chemistry Apparatus (TASCA) is a recoil separator with maximized transmission designed for performing advanced chemical studies as well as nuclear reaction and structure investigations of the transactinide elements ( Z >103) on a one-atom-at-a-time basis. TASCA will provide a very clean transactinide fraction with negligible contamination of lighter elements from nuclear side reactions in the target. For TASCA a new target chamber was designed and built at GSI including the rotating target wheel assembly ARTESIA for beam intensities up to 2 μA (particle). For the production of longer-lived isotopes of neutron-rich heavier actinide and transactinide e…
The application of neutron activation analysis, scanning electron microscope, and radiographic imaging for the characterization of electrochemically …
2008
Lanthanide and actinide targets are prepared at the University of Mainz by molecular plating, an electrochemical deposition from an organic solvent, for heavy-ion reaction studies at GSI. To acquire information about deposition yield, target thickness, and target homogeneity, the following analysis methods are applied. With neutron activation analysis (NAA) the deposition yield and the average thickness of the deposited material is determined. We report on the analytical procedure of NAA performed subsequent to the molecular plating process. Scanning electron microscope (SEM) is used to determine the morphology of the target surfaces. In combination with energy dispersive X-ray spectrometer…
Adamantylcalixarenes with CMPO groups at the wide rim: synthesis and extraction of lanthanides and actinides
2007
Abstract Starting from p -adamantylcalix[4]- and [6]arenes functionalized with carboxylic acid or ester groups at the adamantane nuclei, carbamoylmethylphosphine oxide (CMPO)-containing ligands of a novel type were synthesized. They were studied as extractants for a series of f-block elements including radioactive 152 Eu(III), 241 Am(III), 233 U(VI), and 239 Pu(IV). Tetrameric ligand 4b in which CMPO residues are connected to adamantane nuclei through methylene groups gave the best extraction results for lanthanides and actinides. For all the ligands the extraction efficiency does not decrease at higher nitric acid concentration. Although the discrimination between trivalent actinides and l…
Analysis of the XENON100 dark matter search data
2014
The XENON100 experiment, situated in the Laboratori Nazionali del Gran Sasso, aims at the direct detection of dark matter in the form of weakly interacting massive particles (WIMPs), based on their interactions with xenon nuclei in an ultra low background dual-phase time projection chamber. This paper describes the general methods developed for the analysis of the XENON100 data. These methods have been used in the 100.9 and 224.6 live days science runs from which results on spin-independent elastic, spin-dependent elastic and inelastic WIMP-nucleon cross-sections have already been reported.
Interspecific associations among larval helminths in fish
2001
Various processes can generate associations between the larvae of different helminth species in their fish intermediate or paratenic host. We investigated the pairwise associations among larval helminth species in eight different fish populations, using two different coefficients of associations, in order to determine in what situations they are strongest. All helminth species included use the fish studied as either their second intermediate host or their paratenic host, and are acquired by the fish when it ingests an infected first intermediate host. The intensity of infection correlated positively with fish length for most helminth species. Pairs of species which both exhibited positive c…
REDU : revista de docencia universitaria
2009
[ES] En este artículo se recoge una experiencia que se está diseñando para la asignatura de Sistema Financiero que consistente en diseñar un juego de rol (un juego de simulación) como recurso formativo y gestionarlo a través de Google-Docs, con el objetivo de que el alumno sea capaz de comprender el funcionamiento básico de la negociación en un mercado bursátil. El juego de rol consiste en: diseñar un sistema de juego que establezca las reglas de negociación y determinar los factores aleatorios que pueden afectar positiva o negativamente al valor de las acciones; formar un grupo de alumnos que asuma el papel de Sociedad Rectora y varios grupos que asuman el papel de dealers con el objetivo …