| 1. |
-
- 2019
-
Tidskriftsartikel (refereegranskat)
|
|
| 2. |
|
|
| 3. |
- Sguazzin, M., et al.
(författare)
-
Indirect measurements of neutron -induced reaction cross sections at heavy -ion storage rings
- 2023
-
Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - 2100-014X. ; 284
-
Konferensbidrag (refereegranskat)abstract
- Neutron-induced reaction cross sections of unstable nuclei are essential for understanding the synthesis of heavy elements in stars and for applications in nuclear technology. However, their measurement is very complicated due to the radioactivity of the targets involved. We propose to circumvent this problem by using the surrogate reaction method in inverse kinematics, where the nucleus formed in the neutroninduced reaction of interest is produced by a reaction involving a radioactive heavy -ion beam and a stable, light target nucleus. The probabilities as a function of the compound -nucleus excitation energy for y -ray emission, neutron emission and fission, which can be measured with the surrogate reaction, are particularly useful to constrain model parameters and to obtain more accurate predictions of the neutron-induced reaction cross sections of interest. Yet, the full development of the surrogate method is hampered by numerous longstanding target issues, which can be solved by combining surrogate reactions with the unique and largely unexplored possibilities at heavy -ion storage rings. In this contribution, we describe the developments we are carrying out to measure for the first time simultaneously y-ray emission, neutron emission and fission probabilities at the storage rings of the GSI/FAIR facility. In particular, we will present the first results of the proof of principle experiment, which we performed in June 2022 at the Experimental Storage Ring (ESR)
|
|
| 4. |
- Sguazzin, M., et al.
(författare)
-
Indirect measurements of neutron-induced reaction cross sections at storage rings
- 2023
-
Ingår i: NUCLEAR PHYSICS IN ASTROPHYSICS - X, NPA-X 2022. - : EDP Sciences. - 2100-014X. ; 279
-
Konferensbidrag (refereegranskat)abstract
- Neutron-induced reaction cross sections of unstable nuclei are essential for understanding the synthesis of heavy elements in stars. However, their measurement is very difficult due to the radioactivity of the targets involved. We propose to circumvent this problem by using for the first time the surrogate reaction method in inverse kinematics at heavy-ion storage rings. In this contribution, we describe the developments we have done to perform surrogate-reaction studies at the storage rings of GSI/FAIR. In particular, we present the first results of the proof of principle experiment, which we conducted recently at the Experimental Storage Ring (ESR).
|
|
| 5. |
- Sguazzin, M., et al.
(författare)
-
Determining neutron-induced reaction cross sections through surrogate reactions at storage rings
- 2023
-
Ingår i: Journal of Physics: Conference Series. - 1742-6588 .- 1742-6596. ; 2586:1
-
Konferensbidrag (refereegranskat)abstract
- Determining the cross sections of neutron-induced reactions on short-lived nuclei is imperative to rate calculations in stellar nucleosynthesis and applications of nuclear physics. It is also an immense experimental challenge due to the radioactivity of the targets involved. Our goal is to circumvent this obstacle by using surrogate reactions in inverse kinematics at the heavy-ion storage rings of GSI/FAIR. We present here preliminary results from the first proof of principle experiment, where a beam of 208Pb impinged on a H2 gas jet target in the Experimental Storage Ring (ESR).
|
|
| 6. |
- Sarmiento Pico, Luis, et al.
(författare)
-
Elucidating the nature of the proton radioactivity and branching ratio on the first proton emitter discovered 53mCo
- 2023
-
Ingår i: Nature Communications. - 2041-1723. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- The observation of a weak proton-emission branch in the decay of the 3174keV 53mCo isomeric state marked the discovery of proton radioactivity in atomic nuclei in 1970. Here we show, based on the partial half-lives and the decay energies of the possible proton-emission branches, that the exceptionally high angular momentum barriers, lp = 9 and lp = 7, play a key role in hindering the proton radioactivity from 53mCo, making them very challenging to observe and calculate. Indeed, experiments had to wait decades for significant advances in accelerator facilities and multi-faceted state-of-the-art decay stations to gain full access to all observables. Combining data taken with the TASISpec decay station at the Accelerator Laboratory of the University of Jyväskylä, Finland, and the ACTAR TPC device on LISE3 at GANIL, France, we measured their branching ratios as bp1 = 1.3(1)% and bp2 = 0.025(4)%. These results were compared to cutting-edge shell-model and barrier penetration calculations. This description reproduces the order of magnitude of the branching ratios and partial half-lives, despite their very small spectroscopic factors.
|
|
| 7. |
- Giovinazzo, J., et al.
(författare)
-
4D-imaging of drip-line radioactivity by detecting proton emission from 54mNi pictured with ACTAR TPC
- 2021
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Proton radioactivity was discovered exactly 50 years ago. First, this nuclear decay mode sets the limit of existence on the nuclear landscape on the neutron-deficient side. Second, it comprises fundamental aspects of both quantum tunnelling as well as the coupling of (quasi)bound quantum states with the continuum in mesoscopic systems such as the atomic nucleus. Theoretical approaches can start either from bound-state nuclear shell-model theory or from resonance scattering. Thus, proton-radioactivity guides merging these types of theoretical approaches, which is of broader relevance for any few-body quantum system. Here, we report experimental measurements of proton-emission branches from an isomeric state in 54mNi, which were visualized in four dimensions in a newly developed detector. We show that these decays, which carry an unusually high angular momentum, ℓ = 5 and ℓ = 7, respectively, can be approximated theoretically with a potential model for the proton barrier penetration and a shell-model calculation for the overlap of the initial and final wave functions.
|
|
| 8. |
- Giovinazzo, J., et al.
(författare)
-
Proton 3D tracking and emission time from a short-lived isomer with ACTAR TPC
- 2022
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 1042
-
Tidskriftsartikel (refereegranskat)abstract
- An experiment was conducted at the GANIL/LISE3 facility to produce the 10+ isomer of 54Ni and measure its proton radioactivity decay branches. The proton detection was achieved with the ACTAR TPC device that enabled the separation of the small signal of the emitted proton from the large signal of the implanted ion, while the decay half-life is of the order of 150 ns. From the measured data, the emitted proton track length and the decay time of the ion can be extracted simultaneously. The full proton radioactivity pattern could be established, with two emission branches and their relative branching ratio. Data processing and analysis that allowed to identify and separate the ion and the proton signals in order to reconstruct the particles trajectories and decay time are detailed. The evaluation of the detection efficiency for the proton radioactivity branches based on a full simulation is described.
|
|
| 9. |
- Rudolph, D., et al.
(författare)
-
Mirror symmetry at mass A = 54: E4 effective charges near doubly magic 56Ni
- 2022
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 830
-
Tidskriftsartikel (refereegranskat)abstract
- Proton-emission branches of the 10+ isomer in the Tz=−1 nucleus 54Ni have been imaged with the active target and time projection chamber (ACTAR TPC) in an experiment conducted at the Grand Accélérateur National d'Ions Lourds (GANIL). The completed decay scheme allows derivation of the reduced transition strengths, B(E2;10+→8+) and B(E4;10+→6+), for the two competing γ-ray transitions. By means of a comparison with their well-known ‘mirror transitions’ in Tz=+1 54Fe, and aided by a variety of shell-model calculations in the fp model space, effective charges for E4 transitions near N=Z 56Ni can be deduced: επ≈1.40 and εν≈0.30. Mirror-energy differences are explored with various shell-model interactions and isospin-symmetry breaking terms.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Amundsen, S. S., et al.
(författare)
-
Association analysis of MYO9B gene polymorphisms with celiac disease in a Swedish/Norwegian cohort
- 2006
-
Ingår i: Hum Immunol. - : Elsevier BV. - 0198-8859. ; 67:4-5, s. 341-5
-
Tidskriftsartikel (refereegranskat)abstract
- Association between myosin IXB (MYO9B) gene variants and celiac disease (CD) has been reported in a study of a Dutch cohort. Six single nucleotide polymorphisms (SNPs) within the 3' part of the MYO9B gene showed significant genetic association and formed an associated haplotype. The current study aimed to replicate these findings in a Swedish/Norwegian cohort. Genotyping of the three SNPs which tagged the associated haplotype was performed in a CD family dataset (n = 326) and in an additional set of healthy controls (n = 562). Although our material provided reasonable power to detect the previously observed association, we were unable to replicate association with these SNPs. Lack of reproducibility could be explained by no or negligible contribution of MYO9B to the genetic predisposition to CD in the Swedish/Norwegian population. Alternatively, it might be due to variable linkage disequilibria in distinct populations in the tested SNPs and a causative mutation yet to be identified or to false positive findings (type I error) in the Dutch study.
|
|
| 14. |
- Bjornvold, M., et al.
(författare)
-
FOXP3 polymorphisms in type 1 diabetes and coeliac disease
- 2006
-
Ingår i: J Autoimmun. - : Elsevier BV. - 0896-8411. ; 27:2, s. 140-4
-
Tidskriftsartikel (refereegranskat)abstract
- The FOXP3 gene encodes a transcription factor thought to be essential for the development and function of T regulatory cells. Two previous studies have tested common polymorphisms in FOXP3 for association with type 1 diabetes (T1D) with conflicting results. The aim of our study was to see whether there is any evidence of association between the FOXP3 polymorphisms previously reported to be associated with T1D, in a Caucasian population regarding T1D and coeliac disease (CD). We further looked for evidence of interaction between FOXP3 polymorphisms and HLA-DR3 in conferring susceptibility to T1D. Initially, we analysed two microsatellites in the FOXP3 gene in 363 T1D nuclear families. Our results indicated an association between FOXP3 and T1D (global p=0.004) and a possible interaction between FOXP3 and the HLA-DR3-DQ2 susceptibility haplotype. We then genotyped an additional independent set of 826 T1D patients and 1459 controls as well as one CD dataset consisting of 325 families. A similar tendency was revealed in the CD family material (pnc=0.055 for the associated allele). On the other hand, we were unable to reproduce our initial findings in the T1D case-control dataset (global p=0.6). Our results suggest that the tested FOXP3 markers do not have any major impact on susceptibility for these diseases.
|
|
| 15. |
- Louka, A S, et al.
(författare)
-
The IL12B gene does not confer susceptibility to coeliac disease.
- 2002
-
Ingår i: Tissue antigens. - 0001-2815. ; 59:1, s. 70-2
-
Tidskriftsartikel (refereegranskat)abstract
- Coeliac disease (CD) is a chronic inflammatory disorder where dietary gluten is not tolerated. In the lesion there are gluten reactive T cells predominantly secreting gamma-interferon. Both HLA and non-HLA genes contribute to CD susceptibility. Interleukin-12 (IL-12) regulates gamma-interferon production. The IL12B gene is located in a region (5q31.1-33.1) where there is evidence for linkage with CD. Allele 1 of an IL12B 3'UTR single-nucleotide polymorphism leads to increased expression of IL-12, and was recently implicated in susceptibility for type 1 diabetes (T1D). We found no evidence for association of allele 1 to CD by the transmission/disequilibrium test or case-control approach. No increased frequency was observed in patients belonging to families where the disease was linked to markers on chromosome 5q. Unlike T1D, allele 1 does not appear to confer susceptibility to CD.
|
|
| 16. |
- Amundsen, S. S., et al.
(författare)
-
Genetic analysis of the CD28/CTLA4/ICOS (CELIAC3) region in coeliac disease.
- 2004
-
Ingår i: Tissue antigens. - : Wiley. - 0001-2815 .- 1399-0039. ; 64:5, s. 593-9
-
Tidskriftsartikel (refereegranskat)abstract
- In order to extend our previous findings of genetic linkage to the CD28/CTLA4/ICOS region on chromosome 2q33 (CELIAC3) in coeliac disease (CD), we have investigated 22 genetic markers in 325 Norwegian/Swedish multiplex and simplex CD families. We found both linkage and association with several markers, primarily in the multiplex material. We observed strong linkage disequilibrium (LD) between SNPs (Single Nucleotide Polymorphisms) within an LD block delimited by MH30 and D2S72. A haplotype of this region marked by the alleles -1147*T: + 49*A:CT60*G:CT61*A was significantly associated with CD, suggesting that one or more polymorphisms of this haplotype, possibly -1147*T, are involved in CD susceptibility. The CT60 SNP, a polymorphism found to be most strongly associated with some other immune-mediated diseases, was not associated with CD, as this SNP was part of both associated and non-associated haplotypes. Moreover, our results suggest that CELIAC3 harbours several independent loci contributing to CD susceptibility.
|
|
| 17. |
- Domínguez-Gil, B., et al.
(författare)
-
The Reality of Inadequate Patient Care and the Need for a Global Action Framework in Organ Donation and Transplantation
- 2022
-
Ingår i: Transplantation. ; 106:11, s. 2111-2117
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Transplant therapy is considered the best and often the only available treatment for thousands of patients with organ failure that results from communicable and noncommunicable diseases. The number of annual organ transplants is insufficient for the worldwide need. METHODS: We elaborate the proceedings of the workshop entitled "The Role of Science in the Development of International Standards of Organ Donation and Transplantation," organized by the Pontifical Academy of Sciences and cosponsored by the World Health Organization in June 2021. RESULTS: We detail the urgency and importance of achieving national self-sufficiency in organ transplantation as a public health priority and an important contributor to reaching relevant targets of the United Nations Agenda for Sustainable Development. It details the elements of a global action framework intended for countries at every level of economic development to facilitate either the establishment or enhancement of transplant activity. It sets forth a proposed plan, by addressing the technical considerations for developing and optimizing organ transplantation from both deceased and living organ donors and the regulatory oversight of practices. CONCLUSIONS: This document can be used in governmental and policy circles as a call to action and as a checklist for actions needed to enable organ transplantation as treatment for organ failure. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.
|
|
| 18. |
- Holopainen, Päivi, et al.
(författare)
-
Candidate gene region 2q33 in European families with coeliac disease.
- 2004
-
Ingår i: Tissue antigens. - : Wiley. - 0001-2815 .- 1399-0039. ; 63:3, s. 212-22
-
Tidskriftsartikel (refereegranskat)abstract
- Chromosome region 2q33 harbours a cluster of genes, CTLA-4, CD28, ICOS and closely located PD-1, all related to immune activation and considered as promising candidate genes for susceptibility to coeliac disease (CD). We present here the results of a genetic linkage and association analysis of nine markers located in this gene region in a large combined European material of 796 families with CD from Finland, Sweden, Norway, UK, France and Italy. The joint analysis supports earlier findings that this susceptibility locus, assigned as CELIAC3, merits further studies. Nominally significant linkage to CD was found in 314 families including affected sib pairs. Each of the five populations showed weak associations to several marker alleles, but the analysis revealed, however, no conclusive evidence for a primary functional gene or gene variant present in the total set of families. The results suggest that the CD risk due to 2q33 gene region is complex and may involve more than one susceptibility allele, which possibly differ from other autoimmune diseases.
|
|
| 19. |
- Kleijn, David, et al.
(författare)
-
Delivery of crop pollination services is an insufficient argument for wild pollinator conservation.
- 2015
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.
|
|
| 20. |
- Margaritte-Jeannin, P, et al.
(författare)
-
HLA-DQ relative risks for coeliac disease in European populations: a study of the European Genetics Cluster on Coeliac Disease.
- 2004
-
Ingår i: Tissue antigens. - : Wiley. - 0001-2815 .- 1399-0039. ; 63:6, s. 562-7
-
Tidskriftsartikel (refereegranskat)abstract
- Coeliac disease is an enteropathy due to an intolerance to gluten. The association between HLA-DQ genes and CD is well established. The majority of patients carry the HLA-DQ heterodimer encoded by DQA1*05/DQB1*02, either in cis or in trans. The remaining patients carry either part of the DQ heterodimer or DQA1*03-DQB1*0302. The aim of the study was to estimate the risks associated with different DQ genotypes in European populations. HLA information was available for 470 trio families from four countries: France (117), Italy (128), and Norway and Sweden (225). Five DQA1-DQB1 haplotypes were considered and control haplotype frequencies were estimated from the set of parental haplotypes not transmitted to the affected child. The possible genotypes were grouped into five genotype groups, based on the hierarchy of risk reported in the literature. A north-south gradient in the genotype group frequencies is observed in probands: homogeneity is strongly rejected between all country pairs. For each country, the relative risks associated with each genotype group were computed taking into account the control haplotype frequencies. Homogeneity of relative risks between countries was tested pairwise by maximum likelihood ratio statistics. The hypothesis of homogeneity of relative risks is rejected (P is approximately 10(-6)) for all country pairs. In conclusion, the gradient in the genotype group frequencies in probands is not only due to differences in haplotype frequencies but also due to differences in genotype relative risks in the studied populations; the relative risks associated with each DQ genotype group are different between northern and southern European countries; neither are they ordered in the same way.
|
|
| 21. |
|
|
| 22. |
- Louka, A S, et al.
(författare)
-
HLA in coeliac disease families: a novel test of risk modification by the 'other' haplotype when at least one DQA1*05-DQB1*02 haplotype is carried.
- 2002
-
Ingår i: Tissue antigens. - 0001-2815 .- 1399-0039. ; 60:2, s. 147-54
-
Tidskriftsartikel (refereegranskat)abstract
- Predisposition to coeliac disease (CD) involves HLA genes. We investigated whether any haplotypes modify risk when carried trans to a known high-risk haplotype, DQA1*05-DQB1*02. Earlier attempts to rank levels of risk contributed by the 'other' haplotype were burdened by use of case-control populations; haplotype frequencies were estimated and homozygosity was only presumed. In contrast, exact haplotypes can be determined and allele transmission can be traced in families. A similar study in narcolepsy reported strata of different degrees of predisposition, attributable to the 'other' haplotype. A gene dosage effect similar to that described for DQB1*02 in CD, has also been reported in narcolepsy. We genotyped 439 simplex/multiplex trios for DQA1 and DQB1. We designed a new statistic to test risk modulation by the trans haplotype, even if the affected offspring was homozygous. We tested for significant deviation in transmission of the 'other' haplotype, i.e., modification of DQA1*05-DQB1*02 risk. We also addressed the proposed difference in risk, between DQA1*05-DQB1*02 homozygotes and DQA1*05-DQB1*02/DQA1*0201-DQB1*02 heterozygotes, reported in Southern Europe. We confirmed a DQB1*02 gene dosage effect. However, no haplotypes were found to modify risk when carried trans to DQA1*05-DQB1*02, except DQA1*05-DQB1*02 and DQA1*0201-DQB1*02 which were already known. We did not find credible evidence for a difference in risk conferred by DQA1*05-DQB1*02 and DQA1*0201-DQB1*02, when carried with DQA1*05-DQB1*02. The new test, which directly inspects haplotype transmissions rather than estimated haplotype frequencies, was used to demonstrate that the 'other' haplotype (except DQA1*05-DQB1*02 and DQA1*0201-DQB1*02) does not modify risk conferred by DQA1*05-DQB1*02. The test is applicable to other diseases.
|
|
