Search results for "Ionization"
showing 10 items of 1255 documents
Highly efficient isotope separation and ion implantation of 163Ho for the ECHo project
2019
Abstract The effective electron neutrino mass measurement in the framework of the ECHo experiment requires radiochemically pure 163 Ho, which is ion implanted into detector absorbers. To meet the project specifications in efficiency and purity, the entire process chain of ionization, isotope separation , and implantation of 163Ho was optimized. A new two-step resonant laser ionization scheme was established at the 30 kV magnetic mass separator RISIKO. For ionization and separation, an average efficiency of 69 ( 5 ) stat(4)sys% was achieved using intra-cavity frequency doubled Ti:sapphire lasers. The implantation of undesired 166 m Ho, which is present in trace amounts in the initial 163Ho…
230Th/U-dating of a late Holocene low uranium speleothem from Cuba
2010
We present 22 U-series ages for a stalagmite from north-western Cuba based on multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and thermal ionisation mass spectrometry (TIMS). Our results reveal that the stalagmite continuously grew within the last ~1400a. Low uranium content of the sample and thus, extremely low 230Th concentrations limit the precision and accuracy of 230Th/U-dating by TIMS. Samples measured by MC-ICPMS show a high variability of 232Th content along the growth axis with some sections significantly affected by initial 230Th from a detrital phase. An a-priori bulk earth ratio for (238U/232Th) cannot be used to accurately account for this initial 230Th.…
Developments towards in-gas-jet laser spectroscopy studies of actinium isotopes at LISOL
2015
To study exotic nuclides at the borders of stability with laser ionization and spectroscopy techniques, highest efficiencies in combination with a high spectral resolution are required. These usually opposing requirements are reconciled by applying the in-gas-laser ionization and spectroscopy (IGLIS) technique in the supersonic gas jet produced by a de Laval nozzle installed at the exit of the stopping gas cell. Carrying out laser ionization in the low-temperature and low density supersonic gas jet eliminates pressure broadening, which will significantly improve the spectral resolution. This article presents the required modifications at the Leuven Isotope Separator On-Line (LISOL) facility…
Extended X-ray emission in PKS 1718-649
2018
PKS 1718$-$649 is one of the closest and most comprehensively studied candidates of a young active galactic nucleus (AGN) that is still embedded in its optical host galaxy. The compact radio structure, with a maximal extent of a few parsecs, makes it a member of the group of compact symmetric objects (CSO). Its environment imposes a turnover of the radio synchrotron spectrum towards lower frequencies, also classifying PKS 1718$-$649 as gigahertz-peaked radio spectrum (GPS) source. Its close proximity has allowed the first detection of extended X-ray emission in a GPS/CSO source with Chandra that is for the most part unrelated to nuclear feedback. However, not much is known about the nature …
Wind-luminosity evolution in NLS1 AGN 1H 0707−495
2021
Ultra-fast outflows (UFOs) have been detected in the high-quality X-ray spectra of a number of active galactic nuclei (AGN) with fairly high accretion rates and are thought to significantly contribute to the AGN feedback. After a decade of dedicated study, their launching mechanisms and structure are still not well understood, but variability techniques may provide useful constraints. In this work, therefore, we perform a flux-resolved X-ray spectroscopy on a highly accreting and variable NLS1 AGN, 1H 0707-495, using all archival XMM-Newton observations to study the structure of the UFO. We find that the wind spectral lines weaken at higher luminosities, most likely due to an increasing ion…
Application of LA-ICP-MS as a rapid tool for analysis of elemental impurities in active pharmaceutical ingredients.
2014
The control of inorganic contaminants in active pharmaceutical ingredients has a significant role in the quality control of drug products. The concentration limits for metal residues in drug products have been defined by various regulatory guidelines. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful and fast analytical technique for multi-elemental analysis. A disadvantage in using LA-ICP-MS method is the lack of matrix reference materials for validation and calibration purposes. This article focuses on the handling strategy of laboratory-made matrix calibration standards for the quantification of elemental impurities in an active pharmaceutical ingredie…
Determination of four parabens and bisphenols A, F and S in human breast milk using QuEChERS and liquid chromatography coupled to mass spectrometry
2018
Abstract For the first time, a multiresidue, sensitive and high throughput method for determination of bisphenol A, F and S and 4 parabens (methyl paraben, ethyl paraben, propyl paraben and butyl paraben) in human breast milk was developed. The proposed method includes an extraction and clean-up procedure based on QuEChERS methodology followed by liquid chromatography coupled to triple quadrupole mass spectrometry determination. Negative atmospheric pressure chemical ionization in the selected reaction monitoring mode was used for mass detection. During the method validation the recoveries varied between 83 and 115% with a precision lower than 20% for all analytes using spiked levels from 0…
Corynebacterium aquatimens sp. nov., a lipophilic Corynebacterium isolated from blood cultures of a patient with bacteremia
2012
An unknown lipophilic coryneform bacterium isolated from the blood cultures of a patient with bacteremia was characterized by phenotypic and molecular genetic methods. Chemical analysis revealed the presence of short chain mycolic acids consistent with the genus Corynebacterium. The DNA G+C content was 60.8 mol%. Comparative 16S rRNA gene sequence analysis demonstrated that the isolate represents a new subline within the genus Corynebacterium. The closely phylogenetic relative of the unknown bacterium was found to be C. tuscaniense (97.8% sequence similarity). Partial rpoB gene sequence revealed that strain IMMIB L-2475(T) exhibited 13.5% sequence divergence with C. tuscaniense. The unknown…
Development of a novel methodology for determination of dialkyl phosphates in human urine using liquid chromatography-tandem mass spectrometry
2019
Abstract In this study a fast and sensitive method was developed for the quantitative determination of six dialkyl phosphates (DAPs) in human urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proposed methodology was based on liquid-liquid extraction (LLE) with diethyl ether and ethyl acetate using MgSO4 and NaCl, followed by liquid chromatography and mass spectrometry detection in the selected reaction mode (SRM) with negative electrospray ionization (ESI-). Detection settings were optimized by design of experiments (DoE). Dibutyl phosphate (DBP) was used as internal standard. Several criteria established in the SANTE/11813/2017 guidance document for pesticide resi…
Increased protein kinase A regulatory subunit content and cGMP binding in erythrocyte membranes in liver cirrhosis
2003
Abstract Background/Aims : Patients with liver disease show increased plasma cGMP and decreased intracellular cGMP in lymphocytes. The initial aim of this work was to assess whether decreased intracellular cGMP and increased plasma cGMP may be due to increased ATP-dependent release of cGMP from cells. The results obtained led to a new aim: to identify and quantify a protein responsible for the increased cGMP binding found in erythrocyte membranes from patients with liver disease. Methods : ATP-dependent cGMP transport was determined in inside-out vesicles from erythrocyte membranes. cGMP-binding proteins were isolated from the membranes and identified by MALDI-TOF peptide mass fingerprint. …