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1.
Phys Rev Lett ; 124(3): 032502, 2020 Jan 24.
Article in English | MEDLINE | ID: mdl-32031845

ABSTRACT

Radioactive ^{129}Sb, which can be treated as a proton plus semimagic ^{128}Sn core within the particle-core coupling scheme, was studied by Coulomb excitation. Reduced electric quadrupole transition probabilities, B(E2), for the 2^{+}⊗πg_{7/2} multiplet members and candidate πd_{5/2} state were measured. The results indicate that the total electric quadrupole strength of ^{129}Sb is a factor of 1.39(11) larger than the ^{128}Sn core, which is in stark contrast to the expectations of the empirically successful particle-core coupling scheme. Shell-model calculations performed with two different sets of nucleon-nucleon interactions suggest that this enhanced collectivity is due to constructive quadrupole coherence in the wave functions stemming from the proton-neutron residual interactions, where adding one nucleon to a core near a double-shell closure can have a pronounced effect. The enhanced electric quadrupole strength is an early signal of the emerging nuclear collectivity that becomes dominant away from the shell closure.

2.
Clin Immunol ; 203: 45-52, 2019 06.
Article in English | MEDLINE | ID: mdl-30974290

ABSTRACT

OBJECTIVE: To determine the role of the NLRP3 inflammasome by using the selective NLRP3 inhibitor MCC950 in patients with NLRP3 low penetrance variants and clinical symptoms suggestive for an autoinflammatory syndrome including central nervous system (CNS) involvement. METHODS: Nineteen symptomatic patients with low penetrance NLRP3 variants (Q703K n = 17, V198M n = 2) recruited between 2011 and 2017 were included in this monocentric study. A functional inflammasome activation assay was performed in patients in comparison to healthy controls (HC), including the determination of interleukin-1beta (IL-1ß), interleukin-6 (IL-6) and tumor-necrosis factor alpha (TNF-α) secretion in the presence of the NLRP3 selective small-molecule inhibitor MCC950. Detailed clinical features were assessed and anti-IL-1 treatment response was determined. RESULTS: Peripheral blood mononuclear cells (PBMC) from patients with low penetrance NLRP3 variants displayed enhanced IL-1ß levels following inflammasome activation compared to HC. Furthermore, IL-1ß release was NLRP3-dependent as it was blocked by MCC950. The production of IL-6 and TNF-α was also increased in patients with low penetrance NLRP3 variants. Clinically, they presented with a heterogenous spectrum of neurological manifestations, while cranial nerve inflammation was the most common feature. Overall inflammasome activation did not correlate with disease severity. Eight of ten treated patients responded to anti IL-1 treatment, however a complete response was only documented in four patients. CONCLUSION: PBMC of several patients with NLRP3 low penetrance variants and CNS manifestation showed increased NLRP3-specific IL-1ß release upon stimulation and elevated NLRP3-independent IL-6 and TNF-α levels as those were not suppressed by MCC950. Our data suggest that beside the possible causal involvement of the NLRP3 inflammasome additional, yet unidentified genetic or environmental factors may contribute to the multi-organ inflammation in our patients and explain the partial response to IL-1 targeting therapies.


Subject(s)
Cranial Nerves/immunology , Hereditary Autoinflammatory Diseases/immunology , Inflammasomes/metabolism , Interleukin-1beta/metabolism , Leukocytes, Mononuclear/physiology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Nervous System Diseases/immunology , Adult , Cells, Cultured , Female , Follow-Up Studies , Furans/pharmacology , Hereditary Autoinflammatory Diseases/genetics , Heterocyclic Compounds, 4 or More Rings , Humans , Indenes , Interleukin-6/metabolism , Male , Middle Aged , Molecular Targeted Therapy , Mutation/genetics , NLR Family, Pyrin Domain-Containing 3 Protein/antagonists & inhibitors , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Nervous System Diseases/genetics , Penetrance , Sulfonamides/pharmacology , Sulfones , Tumor Necrosis Factor-alpha/metabolism
3.
Phys Rev Lett ; 119(5): 052503, 2017 Aug 04.
Article in English | MEDLINE | ID: mdl-28949741

ABSTRACT

We report the results of a ß-decay study of fission products ^{86}Br, ^{89}Kr, ^{89}Rb, ^{90gs}Rb, ^{90m}Rb, ^{90}Kr, ^{92}Rb, ^{139}Xe, and ^{142}Cs performed with the Modular Total Absorption Spectrometer (MTAS) and on-line mass-separated ion beams. These radioactivities were assessed by the Nuclear Energy Agency as having high priority for decay heat analysis during a nuclear fuel cycle. We observe a substantial increase in ß feeding to high excited states in all daughter isotopes in comparison to earlier data. This increases the average γ-ray energy emitted by the decay of fission fragments during the first 10 000 s after fission of ^{235}U and ^{239}Pu by approximately 2% and 1%, respectively, improving agreement between results of calculations and direct observations. New MTAS results reduce the reference reactor ν[over ¯]_{e} flux used to analyze reactor ν[over ¯]_{e} interaction with detector matter. The reduction determined by the ab initio method for the four nuclear fuel components, ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu, amounts to 0.976, 0.986, 0.983, and 0.984, respectively.

4.
Phys Rev Lett ; 118(9): 092503, 2017 Mar 03.
Article in English | MEDLINE | ID: mdl-28306272

ABSTRACT

Radioactive ^{136}Te has two valence protons and two valence neutrons outside of the ^{132}Sn double shell closure, providing a simple laboratory for exploring the emergence of collectivity and nucleon-nucleon interactions. Coulomb excitation of ^{136}Te on a titanium target was utilized to determine an extensive set of electromagnetic moments for the three lowest-lying states, including B(E2;0_{1}^{+}→2_{1}^{+}), Q(2_{1}^{+}), and g(2_{1}^{+}). The results indicate that the first-excited state, 2_{1}^{+}, composed of the simple 2p⊕2n system, is prolate deformed, and its wave function is dominated by excited valence neutron configurations, but not to the extent previously suggested. It is demonstrated that extreme sensitivity of g(2_{1}^{+}) to the proton and neutron contributions to the wave function provides unique insight into the nature of emerging collectivity, and g(2_{1}^{+}) was used to differentiate among several state-of-the-art theoretical calculations. Our results are best described by the most recent shell model calculations.

5.
Phys Rev Lett ; 117(9): 092501, 2016 Aug 26.
Article in English | MEDLINE | ID: mdl-27610847

ABSTRACT

We report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs ß decays, which are the most important contributors to the high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three ß decays contribute 43% of the ν[over ¯]_{e} flux near 5.5 MeV emitted by nuclear reactors. This ν[over ¯]_{e} energy is particularly interesting due to spectral features recently observed in several experiments including the Daya Bay, Double Chooz, and RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory by means of proton-induced fission of ^{238}U with on-line mass separation of fission fragments and the Modular Total Absorption Spectrometer. We observe a ß-decay pattern that is similar to recent measurements of ^{92}Rb, with a ground-state to ground-state ß feeding of 91(3)%. We verify the ^{96gs}Y ground-state to ground-state ß feeding of 95.5(20)%. Our measurements substantially modify the ß-decay feedings of ^{142}Cs, reducing the ß feeding to ^{142}Ba states below 2 MeV by 32% when compared with the latest evaluations. Our results increase the discrepancy between the observed and the expected reactor ν[over ¯]_{e} flux between 5 and 7 MeV, the maximum excess increases from ∼10% to ∼12%.

6.
Phys Rev Lett ; 117(9): 092502, 2016 Aug 26.
Article in English | MEDLINE | ID: mdl-27610848

ABSTRACT

The ß-delayed neutron emission of ^{83,84}Ga isotopes was studied using the neutron time-of-flight technique. The measured neutron energy spectra showed emission from states at excitation energies high above the neutron separation energy and previously not observed in the ß decay of midmass nuclei. The large decay strength deduced from the observed intense neutron emission is a signature of Gamow-Teller transformation. This observation was interpreted as evidence for allowed ß decay to ^{78}Ni core-excited states in ^{83,84}Ge favored by shell effects. We developed shell model calculations in the proton fpg_{9/2} and neutron extended fpg_{9/2}+d_{5/2} valence space using realistic interactions that were used to understand measured ß-decay lifetimes. We conclude that enhanced, concentrated ß-decay strength for neutron-unbound states may be common for very neutron-rich nuclei. This leads to intense ß-delayed high-energy neutron and strong multineutron emission probabilities that in turn affect astrophysical nucleosynthesis models.

7.
J Exp Psychol Learn Mem Cogn ; 40(1): 41-65, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23978235

ABSTRACT

Advances in dual-retrieval models of recall make it possible to use clinical data to test theoretical hypotheses about mild cognitive impairment (MCI) and Alzheimer's dementia (AD), the most common forms of neurocognitive impairment. Hypotheses about the nature of the episodic memory declines in these diseases, about decline versus sparing of specific processes, and about which individuals will become impaired over time can all be rigorously tested. Basic theoretical principles, such as whether recollection and reconstruction are distinct retrieval processes, can also be evaluated. In 3 studies, measurements of recollective retrieval, reconstructive retrieval, and familiarity judgment were extracted from standard clinical instruments, for healthy subjects and for subjects with MCI and AD diagnoses. Differences in reconstructive retrieval consistently distinguished MCI and AD, in nationally representative subject samples as well as in highly educated samples, and recollective retrieval also distinguished them in highly educated samples. Dual-retrieval processes were accurate predictors of future conversion to MCI and AD over periods of 1.5-6 years and were better predictors than the best genetic marker of these conditions (the ε4 allele of the APOE genotype). The standard recollection-deficit account of memory declines in MCI and AD was not supported, but the data were consistent with an alternative account that stresses the increasing importance of reconstruction deficits as older adults convert to these diseases.


Subject(s)
Alzheimer Disease/complications , Cognition Disorders/complications , Memory Disorders/etiology , Mental Recall/physiology , Aged , Aged, 80 and over , Female , Humans , Male , Memory Disorders/diagnosis , Neuropsychological Tests , Predictive Value of Tests , Probability
8.
Phys Rev Lett ; 111(11): 112502, 2013 Sep 13.
Article in English | MEDLINE | ID: mdl-24074079

ABSTRACT

A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

9.
Phys Rev Lett ; 111(13): 132502, 2013 Sep 27.
Article in English | MEDLINE | ID: mdl-24116772

ABSTRACT

Beta decay of 86Ga was studied by means of ß-neutron-γ spectroscopy. An isotopically pure ^{86}Ga beam was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and high-resolution electromagnetic separation. The decay of 86Ga revealed a half-life of 43(-15)(+21) ms and large ß-delayed one-neutron and two-neutron branching ratios of P1n=60(10)% and P2n=20(10)%. The ßγ decay of 86Ga populated a 527 keV transition that is interpreted as the deexcitation of the first 2+ state in the N=54 isotone 86Ge and suggests a quick onset of deformation in Ge isotopes beyond N=50.

10.
Neuropsychology ; 27(1): 86-94, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23356599

ABSTRACT

OBJECTIVE: The ε4 allele of the apolipoprotein E (APOE) genotype is the most widely accepted genetic risk factor for Alzheimer's dementia (AD), but findings on whether it is a risk factor for the AD prodrome, mild cognitive impairment (MCI), have been inconsistent. In a prospective longitudinal design, we investigated (a) whether transitions to MCI and other forms of neurocognitive impairment without dementia (CIND) are more frequent among normal ε4 carriers than among noncarriers and (b) whether subsequent transitions to AD from MCI and from other forms of CIND are more frequent among ε4 carriers than among noncarriers. METHOD: The frequency of the ε4 allele was studied in older adults (mean age > 70), who had participated in two or more waves of neuropsychological testing and diagnosis in the Aging, Demographics, and Memory Study (ADAMS) of the United States Department of Health and Human Services, National Institutes of Health, National Institute on Aging's Health and Retirement Study, conducted by the University of Michigan. The association between ε4 and longitudinal transitions to specific types of CIND and dementia can be determined with this data set. RESULTS: Epsilon 4 increased the rate of progression from normal functioning to MCI (58% of new diagnoses were carriers) but not to other forms of CIND. The rate of progression to AD from MCI or from other forms of CIND was not increased by ε4. CONCLUSIONS: The results support the hypothesis that ε4 is a risk factor for transitions from normal functioning to MCI but not for subsequent transitions to AD. In the ADAMS sample, the reason ε4 is elevated in AD individuals is because it is already elevated in MCI individuals, who are the primary source of new AD diagnoses.


Subject(s)
Alzheimer Disease/genetics , Apolipoproteins E/genetics , Cognitive Dysfunction/genetics , Genetic Predisposition to Disease/genetics , Aged , Aged, 80 and over , Disease Progression , Female , Genetic Testing , Genotype , Humans , Logistic Models , Longitudinal Studies , Male , National Institutes of Health (U.S.) , Neuropsychological Tests , Risk Factors , United States
11.
Phys Rev Lett ; 109(11): 112501, 2012 Sep 14.
Article in English | MEDLINE | ID: mdl-23005622

ABSTRACT

The ß decays of neutron-rich nuclei near the doubly magic (78)Ni were studied at the Holifield Radioactive Ion Beam Facility using an electromagnetic isobar separator. The half-lives of (82)Zn (228±10 ms), (83)Zn (117±20 ms), and (85)Ga (93±7 ms) were determined for the first time. These half-lives were found to be very different from the predictions of the global model used in astrophysical simulations. A new calculation was developed using the density functional model, which properly reproduced the new experimental values. The robustness of the new model in the (78)Ni region allowed us to extrapolate data for more neutron-rich isotopes. The revised analysis of the rapid neutron capture process in low entropy environments with our new set of measured and calculated half-lives shows a significant redistribution of predicted isobaric abundances strengthening the yield of A>140 nuclei.

12.
Phys Rev Lett ; 107(20): 202701, 2011 Nov 11.
Article in English | MEDLINE | ID: mdl-22181728

ABSTRACT

The fusion excitation functions for radioactive (132)Sn + (58)Ni and stable (130)Te + (58,64)Ni were measured at energies near the Coulomb barrier. The coupling of transfer channels in heavy-ion fusion was examined through a comparison of Sn + Ni and Te + Ni systems, which have large variations in the number of positive Q-value nucleon transfer channels. In contrast with previous experimental comparisons, where increased sub-barrier fusion cross sections were observed in systems with positive Q-value neutron transfer channels, the reduced excitation functions were equivalent for the different Sn + Ni and Te + Ni systems. The present results suggest a dramatically different influence of positive Q-value transfer channels on the fusion process for the Sn + Ni and Te + Ni systems.

13.
Phys Rev Lett ; 105(16): 162502, 2010 Oct 15.
Article in English | MEDLINE | ID: mdl-21230967

ABSTRACT

By studying the (109)Xe→(105)Te→(101)Sn superallowed α-decay chain, we observe low-lying states in (101)Sn, the one-neutron system outside doubly magic (100)Sn. We find that the spins of the ground state (J=7/2) and first excited state (J=5/2) in (101)Sn are reversed with respect to the traditional level ordering postulated for (103)Sn and the heavier tin isotopes. Through simple arguments and state-of-the-art shell-model calculations we explain this unexpected switch in terms of a transition from the single-particle regime to the collective mode in which orbital-dependent pairing correlations dominate.

14.
Phys Rev Lett ; 102(14): 142502, 2009 Apr 10.
Article in English | MEDLINE | ID: mdl-19392431

ABSTRACT

The beta-delayed neutron branching ratios (P{betan}) for nuclei near doubly magic 78Ni have been directly measured using a new method combining high-resolution mass separation, reacceleration, and digital beta-gamma spectroscopy of 238U fission products. The P{betan} values for the very neutron-rich isotopes ;{76-78}Cu and 83Ga were found to be much higher than previously reported and predicted. Revised calculations of the betan process, accounting for new mass measurements and an inversion of the pi2p{3/2} and pi1f{5/2} orbitals, are in better agreement with these new experimental results.

15.
Phys Rev Lett ; 98(21): 212501, 2007 May 25.
Article in English | MEDLINE | ID: mdl-17677769

ABSTRACT

An alpha-decay branch of (1.4+/-0.4) x 10(-4) has been discovered in the decay of 109I, which predominantly decays via proton emission. The measured Q(alpha) value of 3918+/-21 keV allows the indirect determination of the Q value for proton emission from 105Sb of 356+/-22 keV, which is approximately of 130 keV more bound than previously reported. This result is relevant for the astrophysical rapid proton-capture process, which would terminate in the 105Sn(p,gamma)106Sb(p,gamma)107Te(alpha decay)103Sn cycle at the densities expected in explosive hydrogen burning scenarios, unless unusually strong pairing effects result in a 103Sn(p,gamma)104Sb(p,gamma)105Te(alpha decay)101Sn) cycle.

16.
Phys Rev Lett ; 97(8): 082501, 2006 Aug 25.
Article in English | MEDLINE | ID: mdl-17026296

ABSTRACT

Two new alpha emitters 109Xe and 105Te were identified through the observation of the 109Xe --> 105Te --> 101Sn alpha-decay chain. The 109Xe nuclei were produced in the fusion-evaporation reaction 54Fe(58Ni,3n)109Xe and studied using the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. Two transitions at Ealpha = 4062 +/- 7 keV and Ealpha = 3918 +/- 9 keV were interpreted as the l = 2 and l = 0 transitions from the 7/2+ ground state in 109Xe (T1/2 = 13 +/- 2 ms) to the 5/2+ ground state and a 7/2+ excited state, located at 150 +/- 13 keV in 105Te. The observation of the subsequent decay of 105Te marks the discovery of the lightest known alpha-decaying nucleus. The measured transition energy Ealpha = 4703 +/- 5 keV and half-life T1/2 = 620 +/- 70 ns were used to determine the reduced alpha-decay width delta2. The ratio delta105Te(2)/delta213Po(2) of approximately 3 indicates a superallowed character of the alpha emission from 105Te.

17.
Phys Rev Lett ; 94(19): 192501, 2005 May 20.
Article in English | MEDLINE | ID: mdl-16090167

ABSTRACT

Following Coulomb excitation of the radioactive ion beam (RIB) 132Te at HRIBF we report the first use of the recoil-in-vacuum (RIV) method to determine the g factor of the 2(+)(1) state: g(973.9 keV 2(+) 132Te) = (+)0.35(5). The advantages offered by the RIV method in the context of RIBs and modern detector arrays are discussed.

18.
Phys Rev Lett ; 91(15): 152701, 2003 Oct 10.
Article in English | MEDLINE | ID: mdl-14611462

ABSTRACT

Evaporation residue cross sections have been measured with neutron-rich radioactive 132Sn beams on 64Ni in the vicinity of the Coulomb barrier. The average beam intensity was 2 x 10(4) particles per second and the smallest cross section measured was less than 5 mb. Large sub-barrier fusion enhancement was observed. Coupled-channel calculations taking into account inelastic excitation significantly underpredict the measured cross sections below the barrier. The presence of several neutron transfer channels with large positive Q values suggests that multinucleon transfer may play an important role in enhancing the fusion of 132Sn and 64Ni.

19.
Phys Rev Lett ; 90(1): 012502, 2003 Jan 10.
Article in English | MEDLINE | ID: mdl-12570604

ABSTRACT

Fine structure in proton emission from the 3.1(3) mus activity of 145Tm was discovered by using a novel technique of digital processing of overlapping recoil implantation and decay signals. Proton transitions to the ground state of 144Er and to its first excited 2(+) state at 0.33(1) MeV with a branching ratio I(p)(2(+))=9.6+/-1.5% were observed. The structure of the 145Tm wave function and the emission process were analyzed by using particle-core vibration coupling models.

20.
Phys Rev Lett ; 88(22): 222501, 2002 Jun 03.
Article in English | MEDLINE | ID: mdl-12059416

ABSTRACT

The B(E2;0(+)-->2+) values for the first 2+ excited states of neutron-rich 132,134,136Te have been measured using Coulomb excitation of radioactive ion beams. The B(E2) values obtained for 132,134Te are in excellent agreement with expectations based on the systematics of heavy stable Te isotopes, while that for 136Te is unexpectedly small. These results are discussed in terms of proton-neutron configuration mixing and shell-model calculations using realistic effective interactions.

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