Search results for "LIFETIME"
showing 10 items of 212 documents
Is physical activity a cause of longevity? It is not as straightforward as some would believe : A critical analysis
2018
There are discrepant findings between (A) observational follow-ups and (B) interventional studies that investigate possible causal association between high physical activity and low mortality. Participation in vigorous physical activity at a specific time-point is an indicator of good fitness and health, and is associated with a reduced risk of death. However, neither randomised controlled trials nor experimental animal studies have provided conclusive evidence to show that physical activity started during adulthood extends lifespan. Consequently, the undisputed health-related benefits of exercise have yet to translate into any proven causal relationship with longevity. Physical activity im…
Interactions between silver nanoparticles and fluorescent phytochromes from Deinococcus radiodurans
2017
Poikkitieteelliset sovellukset ovat viime aikoina yleistyneet tieteellisessä tutkimuksessa. Tämä näkyy hyvin esimerkiksi elävän kudoksen kuvantamisen kehittymisessä, jota varten etsitään jatkuvasti parempia biologisia leimoja fysiikan ja kemian keinoin. Tässä tutkielmassa on kehitetty ensimmäinen lähi-infrapuna-alueen fluoresenssileima, joka hyödyntää hopeananopartikkeleja ja fytokromeja. Kompleksi on syntetisoitu itse ja sen rakenne on todennettu optisen spektroskopian, elektroforeesin ja elektronimikroskopian keinoin. Lupaavat fluoresenssiominaisuudet saatiin käyttämällä monomeerisen Deinococcus radiodurans -fytokromin kromoforia sitovaa domeenia (CBDmon). Hopeapartikkelien läsnäollessa C…
Damage accumulation and life prediction in carbon fibre composite pressure vessels
2009
Composites and nanostructures
Decay studies of the long-lived states in Tl186
2020
Decay spectroscopy of the long-lived states in 186Tl has been performed at the ISOLDE Decay Station at ISOLDE, CERN. The α decay from the low-spin (2−) state in 186Tl was observed for the first time and a half-life of 3.4+0.5−0.4 s was determined. Based on the α-decay energy, the relative positions of the long-lived states were fixed, with the (2−) state as the ground state, the 7(+) state at 77(56) keV, and the 10(−) state at 451(56) keV. The level scheme of the internal decay of the 186Tl(10(−)) state [T1/2=3.40(9) s], which was known to decay solely through emission of 374-keV γ-ray transition, was extended and a lower limit for the β-decay branching bβ>5.9(3)% was determined. The extrac…
Isomeric 13/2+ state in 201Fr
2020
We have identified an isomeric state in 201Fr for which we propose a spin and parity of 13/2 +, and interpret it as arising from the π(i13/2 ) configuration. A half-life of 720(40) ns was measured, corresponding to B(M2) = 0.17(2) W.u., in good agreement with those of other 13/2 + → 9/2 − [π(i13/2 ) → π(h9/2 )] transitions observed in other nuclei in the region. The nuclei of interest were produced in a fusion-evaporation reaction and their decay properties were investigated using the GREAT spectrometer at the focal plane of the RITU gas-filled recoil separator. peerReviewed
Fine structure in the α decay of high-spin isomers in 155Lu and 156Hf
2018
Fine structure in the α decay of high-spin isomers in 155Lu(25/2−) and 156Hf (8+) has been studied for the first time using αγ -coincidence analysis. Three new α decays from 155Lu(25/2−) and two from 156Hf (8+) have been identified, populating seniority s > 1 states in the N = 82 nuclei 151Tm and 152Yb, respectively. The reduced hindrance factors of the α decays support the previous configuration assignments of the populated states. This is the first observation of states with excitation energy greater than 1.5 MeV being populated following α decay in nuclei outside of the 208Pb region. peerReviewed
Lifetime measurements of lowest states in the π g7/2 ⊗ νh11/2 rotational band in 112I
2018
A differential-plunger device was used to measure the lifetimes of the lowest states in the πg7/2 ⊗ νh11/2 rotational band in doubly odd 112I with the 58Ni(58Ni, 3pn) reaction. A differential decay curve method was performed using the fully shifted and degraded γ -ray intensity measurements as a function of target-to-degrader distance. The lifetimes of the lowest three states in the πg7/2 ⊗ νh11/2 band in 112I were measured to be 124(30), 130(25), and 6.5(5) ps, respectively. As the lifetimes of successive excited states in a rotational band are expected to decrease with increasing excitation energy, these measurements suggest that the order of the transitions in the established band in 112…
Level structure above the 17+ isomeric state in 152 69 Tm83
2018
Excited states above the 17+ isomeric state in the proton-rich nucleus 152Tm were established by employing the recoil-isomer tagging technique. Data were collected using the JUROGAM gamma-ray array and the GREAT spectrometer together with the recoil ion transport unit (RITU) gas-filled recoil separator and analyzed to identify the prompt and delayed γ decays from the levels in 152Tm. Shell-model calculations, either in a large valence space or in a reduced model space with five protons in the π0h11/2 orbital and one neutron in the ν1f7/2 orbital, agree with the observed energies of the yrast levels up to angular momentum J = 21. The observation of near degeneracies in the energy spectrum ca…
Lifetime Measurements of Excited States in $^{172}$Pt and the Variation of Quadrupole Transition Strength with Angular Momentum
2018
Lifetimes of the first excited 2 + and 4 + states in the extremely neutron-deficient nuclide 172 Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B ( E 2 : 4 + 1 → 2 + 1 ) / B ( E 2 : 2 + 1 → 0 + gs ) = 0.55 ( 19 ) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N ≈ 90 – 94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B ( E 2 : 4 + 1 → …
Identification of a 6.6μs isomeric state in 175Ir
2019
An experiment has been performed to study excited states in the neutron-deficient nucleus 175Ir via the use of the JUROGAM II high-purity germanium detector array and the RITU gas-filled separator at JYFL, Jyväskylä. By using isomer tagging, an isomeric state with a half-life of 6.58(15) μs has been observed in 175Ir for the first time. It has been established that the isomer decays via a 45.2 (E1)–26.1 (M1) keV cascade to new states below the previously reported ground state in 175Ir with Iπ = (5/2−). We now reassign this (5/2−) state to the isomeric state discovered in this study. peerReviewed