Nuclear Charge Radii of the Nickel Isotopes

Collinear laser spectroscopy is performed on the nickel isotopes ^{58-68,70}Ni, using a time-resolved photon counting system. From the measured isotope shifts, nuclear charge radii R_{c} are extracted and compared to theoretical results. Three ab initio approaches all employ, among others, the chiral interaction NNLO_{sat}, which allows an assessment of their accuracy. We find agreement with experiment in differential radii δ⟨r_{c}^{2}⟩ for all employed ab initio methods and interactions, while the absolute radii are consistent with data only for NNLO_{sat}. Within nuclear density functional theory, the Skyrme functional SV-min matches experiment more closely than the Fayans functional Fy(Δr,HFB).

Charge Radius of the Short-Lived

We present the first laser spectroscopic measurement of the neutron-rich nucleus ^{68}Ni at the N=40 subshell closure and extract its nuclear charge radius. Since this is the only short-lived isotope for which the dipole polarizability α_{D} has been measured, the combination of these observables provides a benchmark for nuclear structure theory. We compare them to novel coupled-cluster calculations based on different chiral two- and three-nucleon interactions, for which a strong correlation between the charge radius and dipole polarizability is observed, similar to the stable nucleus ^{48}Ca. Three-particle-three-hole correlations in coupled-cluster theory substantially improve the description of the experimental data, which allows to constrain the neutron radius and neutron skin of ^{68}Ni.

Laser Spectroscopy of Neutron-Rich Tin Isotopes: A Discontinuity in Charge Radii across the N=82 Shell Closure.

The change in mean-square nuclear charge radii δ⟨r^{2}⟩ along the even-A tin isotopic chain ^{108-134}Sn has been investigated by means of collinear laser spectroscopy at ISOLDE/CERN using the atomic transitions 5p^{2} ^{1}S_{0}→5p6 s^{1}P_{1} and 5p^{2} ^{3}P_{0}→5p6s ^{3}P_{1}. With the determination of the charge radius of ^{134}Sn and corrected values for some of the neutron-rich isotopes, the evolution of the charge radii across the N=82 shell closure is established. A clear kink at the doubly magic ^{132}Sn is revealed, similar to what has been observed at N=82 in other isotopic chains with larger proton numbers, and at the N=126 shell closure in doubly magic ^{208}Pb. While most standard nuclear density functional calculations struggle with a consistent explanation of these discontinuities, we demonstrate that a recently developed Fayans energy density functional provides a coherent description of the kinks at both doubly magic nuclei, ^{132}Sn and ^{208}Pb, without sacrificing the overall performance. A multiple correlation analysis leads to the conclusion that both kinks are related to pairing and surface effects.

[Pulmonary hypertension in hereditary haemorrhagic teleangiectasia]. / Pulmonalvaskuläre Beteiligung bei Morbus Osler.

BACKGROUND: In hereditary haemorrhagic teleangiectasia (HHT) can be accompanied by pulmonary arteriovenous vascular malformations (PAVM). Pulmonary hypertension (PH) is regarded as a rare pulmonary manifestation. METHODS AND PATIENTS: We non-invasively assessed the pulmonary circulation in 20 patients with HHT using standard resting echocardiography including contrast studies. In 14 patients a mutation in the endoglin gene was present. The other 6 patients carried a mutation in the Alk-1 gene. RESULTS: We identified 4 patients with manifest PH, among them 2 patients (both with endoglin mutations) with concurrent thromboembolism, and 2 patients (both with Alk-1 mutations) with hepatic manifestations of HHT. Two patients required specific pulmonary vasoactive therapy with sildenafil and bosentan, respectively. Another patient received embolisation therapy for hypercirculatory PH due to hepatic arteriovenous malformations. Pulmonary arteriovenous malformations were found in 8 patients (7 with endoglin, and 1 with Alk-1 mutations), among them were 2 patients with PH. CONCLUSIONS: Patients with HHT should undergo echocardiographic screening for PAVM as well as PH. When PH is detected, other conditions such as hepatic or thromboembolic diseases should be considered, regardless of the underlying genetic defect.

Herpesvirus saimiri Tip gene causes T-cell lymphomas in transgenic mice.

New World primates develop T-cell lymphomas on infection with Herpesvirus saimiri. To investigate the oncogenic potential of the Tip gene of Herpesvirus saimiri strain C488, we tried to establish transgenic mice that should express Tip under control of a constitutive promoter. Although transgene-positive embryos were found, lines could not be established. However, using a system in which the transgene has to be activated by a Cre recombinase-mediated deletion, we were able to obtain several Tip transgenic lines. At high expression levels, the mice developed T-cell lymphomas. Thus, Tip can induce lymphomas and is therefore very likely responsible for the oncogenicity of Herpesvirus saimiri.

Mutation analysis in hereditary haemorrhagic telangiectasia in Germany reveals 11 novel ENG and 12 novel ACVRL1/ALK1 mutations.

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal-dominant disease characterized by recurrent epistaxis, mucocutaneous telangiectasias and visceral arteriovenous malformations. Mutations in endoglin (ENG) and activin A receptor type II-like kinase 1 (ACVRL1 or ALK1) have been found in patients with HHT. We have screened a total of 51 unselected German index cases with the suspected diagnosis of HHT. We identified 30 different mutations in 32 cases (62.7%) by direct sequencing. Among these mutations, 11 of 13 ENG mutations and 12 of 17 ACVRL1 mutations were not previously reported in the literature. Two of the ACVRL1 mutations were each shared by two families. An analysis of the genotype-phenotype correlation is consistent with a more common frequency of pulmonary arteriovenous malformations in patients with ENG mutations than in patients with ACVRL1 mutations in our collective.