0000000000583601
AUTHOR
S. Schwarz
Cadmium mass measurements between the neutron shell closures at N=50 and 82
International audience; The mass values of the neutron-deficient cadmium isotopes 99−109Cd and of the neutronrich isotopes 114,120,122−124,126,128Cd have been measured using ISOLTRAP. The behavior of the separation energies of the cadmium isotopes from N = 50 to 82 is discussed.
Mass measurements on neutron-deficient Sr and neutron-rich Sn isotopes with the ISOLTRAP mass spectrometer
Abstract The atomic masses of 76,77,80,81,86,88 Sr and 124,129,130,131,132 Sn were measured by means of the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. 76 Sr is now the heaviest N = Z nucleus for which the mass is measured to a precision better than 35 keV. For the tin isotopes in the close vicinity of the doubly magic nucleus 132 Sn, mass uncertainties below 20 keV were achieved. An atomic mass evaluation was carried out taking other experimental mass values into account by performing a least-squares adjustment. Some discrepancies between older experimental values and the ones reported here emerged and were resolved. The results of the new adjustment and their impact will be pr…
A linear radiofrequency quadrupole ion trap for the cooling and bunching of radioactive ion beams
A linear radiofrequency quadrupole ion guide and beam buncher has been installed at the ISOLTRAP mass spectrometry experiment at the ISOLDE facility at CERN. The apparatus is being used as a beam cooling, accumulation, and bunching system. It operates with a buffer gas that cools the injected ions and converts the quasicontinuous 60- keV beam from the ISOLDE facility to 2.5-keV beam pulses with improved normalized transverse emittance. Recent measurements suggest a capture efficiency of the ion guide of up to 40% and a cooling and bunching efficiency of at least 12% which is expected to still be increased. The improved ISOLTRAP setup has so far been used very successfully in three on-line e…
Direct mass measurements of neutron-deficient xenon isotopes with the ISOLTRAP mass spectrometer
Abstract The masses of Xe isotopes with 124⩾ A ⩾114 have been measured using the ISOLTRAP spectrometer at the on-line mass separator ISOLDE/CERN. A mass resolving power of 500 000 was chosen resulting in an accuracy of δm ≈12 keV for all isotopes investigated. Conflicts with existing mass data of several standard deviations were found.
Direct mass measurements on neutron-deficient xenon isotopes with the ISOLTRAP mass spectrometer
The masses of Xe isotopes with 124 A 114 have been measured using the ISOLTRAP spectrometer at the on-line mass separator ISOLDE/CERN. A mass resolving power of 500000 was chosen resulting in an accuracy of m 12 keV for all isotopes investigated. Con icts with existing mass data of several standard deviations were found. peerReviewed
Esophagogastric cancer: integration of targeted therapies into systemic chemotherapy.
Although combination chemotherapy has been shown to be more effective than single agents in advanced esophagogastric cancer, the better response rates have not fulfilled their promise as overall survival times from best combination still range between 8 to 11 months. So far, the development of targeted therapies stays somewhat behind their integration into treatment concepts compared to other gastrointestinal diseases. Thus, the review summarizes the recent advances in the development of targeted therapies in advanced esophagogastric cancer. The majority of agents tested were angiogenesis inhibitors or agents targeting the epidermal growth factor receptors EGFR1 and HER2. For trastuzumab an…
Cetuximab with irinotecan, folinic acid and 5-fluorouracil as first-line treatment in advanced gastroesophageal cancer: a prospective multi-center biomarker-oriented phase II study.
Abstract Background Cetuximab plus irinotecan/folinic acid/5-fluorouracil (5-FU) (IF) was evaluated as first-line treatment of patients with advanced gastric cancer and gastroesophageal junction tumors. Preplanned analyses of the influence of tumor biomarkers on treatment outcome were carried out. Patients and methods Patients received weekly cetuximab (400 mg/m2 on day 1, subsequently 250 mg/m2) plus irinotecan (80 mg/m2) and a 24-hour continuous infusion of folinic acid (200 mg/m2) and 5-FU (1500 mg/m2) on days 1, 8, 15, 22, 29 and 36 of a 50-day cycle, until progressive disease (PD). Results The most common grade 3/4 toxic effects in 49 patients were diarrhea (15%) and skin toxic effects…
Breakdown of the Isobaric Multiplet Mass Equation atA=33,T=3/2
Mass measurements on ${}^{33,34,42,43}\mathrm{Ar}$ were performed using the Penning trap mass spectrometer ISOLTRAP and a newly constructed linear Paul trap. This arrangement allowed us, for the first time, to extend Penning trap mass measurements to nuclides with half-lives below one second ( ${}^{33}\mathrm{Ar}$: ${T}_{1/2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}174\mathrm{ms}$). A mass accuracy of about ${10}^{\ensuremath{-}7}$ $(\ensuremath{\delta}m\ensuremath{\approx}4\mathrm{keV})$ was achieved for all investigated nuclides. The isobaric multiplet mass equation was checked for the $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}33$, $T\phantom{\rule{0ex}{0ex}}=\phantom…
Production and trapping of carbon clusters for absolute mass measurements at ISOLTRAP
Singly-charged carbon clusters C/sub n//sup +/ (n >or= 1) have been produced by laser-induced desorption and fragmentation of C/sub 60/ fullerenes and have been injected into and stored in the Penning trap system of the ISOLTRAP mass spectrometer at ISOLDE/CERN. The present study is the first step to extend the until now direct mass measurements at ISOLTRAP to absolute mass measurements by using clusters of /sup 12/C. (10 refs).
Direct determination of the mass of28Si as a contribution to a new definition of the kilogram
The mass of 28Si has been determined to be m(28Si) = 27.976 926 57(30) u by comparing the cyclotron frequencies of the singly charged ions 12C+, 12C+3 and 28Si+ in a Penning trap mass spectrometer. The experimental technique and the setup are described. The obtained accuracy as well as possible improvements are discussed. Our measurements are related to current efforts to base the kilogram on atomic properties by using an almost perfect single crystal of silicon.
Progress in Arabidopsis genome sequencing and functional genomics
Arabidopsis thaliana has a relatively small genome of approximately 130 Mb containing about 10% repetitive DNA. Genome sequencing studies reveal a gene-rich genome, predicted to contain approximately 25 000 genes spaced on average every 4.5 kb. Between 10 to 20% of the predicted genes occur as clusters of related genes, indicating that local sequence duplication and subsequent divergence generates a significant proportion of gene families. In addition to gene families, repetitive sequences comprise individual and small clusters of two to three retroelements and other classes of smaller repeats. The clustering of highly repetitive elements is a striking feature of the A. thaliana genome emer…
High-precision Penning-trap mass measurements of heavy xenon isotopes for nuclear structure studies
With the double Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN the masses of the neutron-rich isotopes $^{136\ensuremath{-}146}\mathrm{Xe}$ were measured with a relative uncertainty of the order of ${10}^{\ensuremath{-}8}$ to ${10}^{\ensuremath{-}7}$. In particular, the masses of $^{144\ensuremath{-}146}\mathrm{Xe}$ were measured for the first time. These new mass values allow one to extend calculations of the mass surface in this region. Proton-Neutron interaction strength, obtained from double differences of binding energies, relate to subtle structural effects, such as the onset of octupole correlations, the growth of collectivity, and its relation to the underlying shell model l…
Towards Shorter-Lived Nuclides in ISOLTRAP Mass Measurements
Recently, the applicability of Penning trap mass spectrometry has been extended to nuclides with a half-life of less than one second. The mass of 33Ar(T 1/2 = 174 ms) was measured using the ISOLTRAP spectrometer with an accuracy of 4.2 keV. This measurement provided a stringent test of the Isobaric Multiplet Mass Equation (IMME) at mass number A = 33 and isospin T = 3/2. The fast measurement cycle that shows the way to other measurements of very-short-lived nuclides is presented. Furthermore, the results of the IMME test are displayed.
Extension of Penning-trap mass measurements to very short-lived nuclides
Abstract Mass measurements on 33,34,42,43 Ar have been performed at the ISOLTRAP spectrometer. An accuracy of δm ≈4 keV has been achieved for all measured isotopes. With 33 Ar it is the first time that a nuclide with a half-life shorter than one second has been investigated using a Penning trap. This became possible due to the recently installed linear radio-frequency ion-trap system and an improved, faster measurement cycle.
Plasmavolumenverschiebung und Veränderungen der zentralen Hämodynamik nach Okklusion der A. mesent. sup. und anschließender Reperfusion
Im Schweinemodell wurde die Veranderung des Plasmavolumens bei verschiedenen therapeutischen Ansatzen des Reperfusionsschocks nach 2-stundiger Okklusion der A. mesent. sup. untersucht (keine Therapie, 5–50 μg Dopamin, 40 ml/kg KG isotone Reperfusion in 30 Min., 5 ml/kg KG 7,5% NaCl/10% HAES in 5 Min.). Der Plasmavolumenverlust von >30% in der Kontroll- und Dopamingruppe wurde nur durch die isotone Reperfusion vollstandig ausgeglichen. Die hyperton/hyperonkotische Therapie (-16% PV-Verlust) wies aber ein signifikant verbessertes HZV auf.
High-precision masses of neutron-deficient rubidium isotopes using a Penning trap mass spectrometer
The atomic masses of the neutron-deficient radioactive rubidium isotopes $^{74-77,79,80,83}$Rb have been measured with the Penning trap mass spectrometer ISOLTRAP. Using the time-of-flight cyclotron resonance technique, relative mass uncertainties ranging from $1.6 \times 10^{-8}$ to $5.6 \times 10^{-8}$ were achieved. In all cases, the mass precision was significantly improved as compared with the prior Atomic-Mass Evaluation; no significant deviations from the literature values were observed. The exotic nuclide $^{74}$Rb with a half-life of only 65 ms, is the shortest-lived nuclide on which a high-precision mass measurement in a Penning trap has been carried out. The significance of these…
Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana
The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency …