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- Rodriguez, D., et al.
(författare)
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MATS and LaSpec : High-precision experiments using ion traps and lasers at FAIR
- 2010
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Ingår i: The European physical journal. Special topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 183, s. 1-123
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Forskningsöversikt (refereegranskat)abstract
- Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique ""fingerprint"". Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10(-5) to below 10(-8) for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10(-9) can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e. g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner. The accuracy of laser-spectroscopic-determined nuclear properties is very high. Requirements concerning production rates are moderate; collinear spectroscopy has been performed with production rates as few as 100 ions per second and laser-desorption resonance ionization mass spectroscopy (combined with beta-delayed neutron detection) has been achieved with rates of only a few atoms per second. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy, which will provide a complete system with respect to the physics and isotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams, the two collaborations have a common beamline to stop the radioactive beam of in-flight produced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpec setups, respectively.
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| 2. |
- Jackson, Sarah S., et al.
(författare)
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Anthropometric Risk Factors for Cancers of the Biliary Tract in the Biliary Tract Cancers Pooling Project
- 2019
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Ingår i: Cancer Research. - : AMER ASSOC CANCER RESEARCH. - 0008-5472 .- 1538-7445. ; 79:15, s. 3973-3982
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Tidskriftsartikel (refereegranskat)abstract
- Biliary tract cancers are rare but highly fatal with poorly understood etiology. Identifying potentially modifiable risk factors for these cancers is essential for prevention. Here we estimated the relationship between adiposity and cancer across the biliary tract, including cancers of the gallbladder (GBC), intrahepatic bile ducts (IHBDC), extrahepatic bile ducts (EHBDC), and the ampulla of Vater (AVC). We pooled data from 27 prospective cohorts with over 2.7 million adults. Adiposity was measured using baseline body mass index (BMI), waist circumference, hip circumference, waist-to-hip, and waist-to-height ratios. HRs and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards models adjusted for sex, education, race, smoking, and alcohol consumption with age as the time metric and the baseline hazard stratified by study. During 37,883,648 person-years of follow-up, 1,343 GBC cases, 1,194 EHBDC cases, 784 IHBDC cases, and 623 AVC cases occurred. For each 5 kg/m(2) increase in BMI, there were risk increases for GBC (HR = 1.27; 95% CI, 1.19-1.36), IHBDC (HR = 1.32; 95% CI, 1.21-1.45), and EHBDC (HR = 1.13; 95% CI, 1.03-1.23), but not AVC (HR = 0.99; 95% CI, 0.88-1.11). Increasing waist circumference, hip circumference, waist-to-hip ratio, and waist-to-height ratio were associated with GBC and IHBDC but not EHBDC or AVC. These results indicate that adult adiposity is associated with an increased risk of biliary tract cancer, particularly GBC and IHBDC. Moreover, they provide evidence for recommending weight maintenance programs to reduce the risk of developing these cancers. Significance: These findings identify a correlation between adiposity and biliary tract cancers, indicating that weight management programs may help minimize the risk of these diseases.
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| 3. |
- McGee, Emma E., et al.
(författare)
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Smoking, Alcohol, and Biliary Tract Cancer Risk : A Pooling Project of 26 Prospective Studies
- 2019
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Ingår i: Journal of the National Cancer Institute. - : OXFORD UNIV PRESS INC. - 0027-8874 .- 1460-2105. ; 111:12, s. 1263-1278
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Forskningsöversikt (refereegranskat)abstract
- Background: Tobacco and alcohol are well-established risk factors for numerous cancers, yet their relationship to biliary tract cancers remains unclear. Methods: We pooled data from 26 prospective studies to evaluate associations of cigarette smoking and alcohol consumption with biliary tract cancer risk. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for associations with smoking and alcohol consumption were calculated. Random-effects meta-analysis produced summary estimates. All statistical tests were two-sided. Results: Over a period of 38 369 156 person-years of follow-up, 1391 gallbladder, 758 intrahepatic bile duct, 1208 extrahepatic bile duct, and 623 ampulla of Vater cancer cases were identified. Ever, former, and current smoking were associated with increased extrahepatic bile duct and ampulla of Vater cancers risk (eg, current vs never smokers HR = 1.69, 95% CI = 1.34 to 2.13 and 2.22, 95% CI = 1.69 to 2.92, respectively), with dose-response effects for smoking pack-years, duration, and intensity (all P-trend<.01). Current smoking and smoking intensity were also associated with intrahepatic bile duct cancer (eg, >40 cigarettes per day vs never smokers HR = 2.15, 95 % CI = 1.15 to 4.00; P-trend = .001). No convincing association was observed between smoking and gallbladder cancer. Alcohol consumption was only associated with intrahepatic bile duct cancer, with increased risk for individuals consuming five or more vs zero drinks per day (HR = 2.35, 95%CI = 1.46 to 3.78; P-trend = .04). There was evidence of statistical heterogeneity among several cancer sites, particularly between gallbladder cancer and the other biliary tract cancers. Conclusions: Smoking appears to increase the risk of developing all biliary tract cancers except gallbladder cancer. Alcohol may increase the risk of intrahepatic bile duct cancer. Findings highlight etiologic heterogeneity across the biliary tract.
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| 4. |
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| 5. |
- Jackson, Sarah S., et al.
(författare)
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Associations between reproductive factors and biliary tract cancers in women from the Biliary Tract Cancers Pooling Project
- 2020
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Ingår i: Journal of Hepatology. - : ELSEVIER. - 0168-8278 .- 1600-0641. ; 73, s. 863-872
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Gallbladder cancer (GBC) is known to have a female predominance while other biliary tract cancers (BTCs) have a male predominance. However, the role of female reproductive factors in BTC etiology remains unclear. Methods: We pooled data from 19 studies of >1.5 million women participating in the Biliary Tract Cancers Pooling Project to examine the associations of parity, age at menarche, reproductive years, and age at menopause with BTC. Associations for age at menarche and reproductive years with BTC were analyzed separately for Asian and non-Asian women. Hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards models, stratified by study. Results: During 21,681,798 person-years of follow-up, 875 cases of GBC, 379 of intrahepatic bile duct cancer (IHBDC), 450 of extrahepatic bile duct cancer (EHBDC), and 261 of ampulla of Vater cancer (AVC) occurred. High parity was associated with risk of GBC (HR >= 5 vs. 0 births 1.72; 95% CI 1.25-2.38). Age at menarche (HR per year increase 1.15; 95% CI 1.06-1.24) was associated with GBC risk in Asian women while reproductive years were associated with GBC risk (HR per 5 years 1.13; 95% CI 1.04-1.22) in non-Asian women. Later age at menarche was associated with IHBDC (HR 1.19; 95% CI 1.09-1.31) and EHBDC (HR 1.11; 95% CI 1.01-1.22) in Asian women only. Conclusion: We observed an increased risk of GBC with increasing parity. Among Asian women, older age at menarche was associated with increased risk for GBC, IHBDC, and EHBDC, while increasing reproductive years was associated with GBC in non-Asian women. These results suggest that sex hormones have distinct effects on cancers across the biliary tract that vary by geography. Lay summary: Our findings show that the risk of gallbladder cancer is increased among women who have given birth (especially women with 5 or more children). In women from Asian countries, later age at menarche increases the risk of gallbladder cancer, intrahepatic bile duct cancer and extrahepatic bile duct cancer. We did not see this same association in women from Western countries. Age at menopause was not associated with the risk of any biliary tract cancers. Published by Elsevier B.V. on behalf of European Association for the Study of the Liver.
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