Opažanje α-raspada 10B i 12B u 9Be +7Li reakcijama

The 10B and 12B excitation energy spectra have been obtained from the inclusive and coincident measurements of the 9Be +7Li reactions at Ebeam=52 MeV. Contributions of the 10B states below 10 MeV and of the 12B states below 16 MeV excitation have been resolved. 10B states at 4.77 and 6.56 MeV as well as groups of states around 5.1 and 6 MeV decaying into α +6Li, and of the state at 7.0 MeV decaying into α +6Li∗ have been found. These measurements give the first evidence for α +8Li decay of the 12B states. In our data, there is no evidence for the α +8Li∗ (0.98 MeV) and α +8Li∗ (2.26 MeV) decays of 12B. The influence of α-decaying 12B states on the cross section of the astrophysically important 8Li(α,n)11B reaction is discussed.Odredili smo uzbudne energijske spektre 10B i 12B uključivim i sudesnim mjerenjima reakcije 9Be+7Li na Esnop=52 MeV. Razdvojili smo doprinose stanja 10B ispod 10 MeV i stanja 12B ispod 16 MeV. Našli smo raspade stanja 10B na 4.77 i 6.56 MeV i grupa stanja oko 5.1 i oko 6 MeV u α +6Li, i stanja na 7.0 MeV u α +6Li∗ . Ovo su prva mjerenja u kojima se nalazi α +8Li raspad viših stanja 12B. Naši podaci ne ukazuju prisutnost α +8Li∗ (0.98 MeV) i α +8Li∗ (2.26 MeV) raspada 12B. Raspravljamo utjecaj stanja 12B koja podliježu α-raspadu na udarne presjeke astrofizički važne reakcije 8Li(α,n)11B

10Be i molekulska stanja

The 10Be excitation energy spectra have been obtained from the inclusive and coincident measurements of the reactions: 7Li +7Li at E0 = 8 and 30 MeV and 9Be +7Li at E0 = 52 MeV. Contributions of the 10Be states below 12 MeV in excitation have been observed. Decays of the states at 9.6, 10.2 and 11.8 into a +6He and, for the first time, into a +6He* have been found. The results are discussed in addition to the other experimental data and recent theoretical predictions. Proposals for future measurements to search for exotic structures in carbon nuclei are also made.Proučavamo ekscitacijske energijske spektre 10Be iz inkluzivnih i koincidentnih mjerenja reakcija 7Li +7Li na E0 = 8 i 30 MeV, te 9Be +7Li na E0 = 52 MeV. Opaženi su doprinosi stanja 10Be u energiji uzbude do 12 MeV. Nađeni su raspadi stanja na 9.6, 10.2 i 11.8 MeV na α +6He te, po prvi put, na α +6He∗. Ovi se rezultati razmatraju zajedno s ostalim eksperimentalnim podacima i novijim teorijskim predviđanjima. Predlažu se buduća mjerenja u kojima bi se tražila stanja lakih jezgara egzotične građe

MYC-driven epigenetic reprogramming favors the onset of tumorigenesis by inducing a stem cell-like state

Breast cancer consists of highly heterogeneous tumors, whose cell of origin and driver oncogenes are difficult to be uniquely defined. Here we report that MYC acts as tumor reprogramming factor in mammary epithelial cells by inducing an alternative epigenetic program, which triggers loss of cell identity and activation of oncogenic pathways. Overexpression of MYC induces transcriptional repression of lineage-specifying transcription factors, causing decommissioning of luminal-specific enhancers. MYC-driven dedifferentiation supports the onset of a stem cell-like state by inducing the activation of de novo enhancers, which drive the transcriptional activation of oncogenic pathways. Furthermore, we demonstrate that the MYC-driven epigenetic reprogramming favors the formation and maintenance of tumor-initiating cells endowed with metastatic capacity. This study supports the notion that MYC-driven tumor initiation relies on cell reprogramming, which is mediated by the activation of MYC-dependent oncogenic enhancers, thus establishing a therapeutic rational for treating basal-like breast cancers

Trojan Horse Investigation for AGB Stellar Nucleosynthesis

Asymptotic Giant Branch (AGB) stars are among the most important astrophysical sites influencing the nucleosynthesis and the chemical abundances in the Universe. From a pure nuclear point of view, several processes take part during this peculiar stage of stellar evolution thus requiring detailed experimental cross section measurements. Here, we report on the most recent results achieved via the application of the Trojan Horse Method (THM) and Asymptotic Normalization Coefficient (ANC) indirect techniques, discussing the details of the experimental procedure and the deduced reaction rates. In addition, we report also on the on going studies of interest for AGB nucleosynthesis

Eksperimentalni dokazi (pokazatelji) molekulske strukture lakih jezgri

Experimental studies of the cluster structures in 9,10Be and 13,14C have been performed. Evidence for the α+5He decay of 9Be excited states, α+6He decays of 10Be∗ , α+9Be decay of 13C ∗ and for the decays of 14C ∗ into α+10Be were found. These decay processes indicate the cluster structures of the excited states. The results are compared with recent suggestions for the presence of molecule-like structures based upon α-particles and valence neutrons in Be and C isotopes.Eksperimentalno smo proučavali nakupinske strukture u 9,10Be i 13,14C. Našli smo α+5He raspad uzbuđenog stanja 9Be, α+6He raspad 10Be∗ , α+9Be raspad 13C ∗ te raspad 14C ∗ u α+10Be. Ovi procesi ukazuju na nakupinske strukture uzbuđenih stanja tih jezgri. Ishode mjerenja uspoređujemo s novim objašnjenjima o prisutnosti molekulama-sličnih struktura zasnovanim na α-česticama i valentnim neutronima u izotopima Be i C

The 10B(p,α)7Be S(E)-factor from 5 keV to 1.5 MeV using the Trojan Horse Method

The 10 B(p, α ) 7 Be reaction is the main responsible for the 10 B destruction in stellar interior [1]. In such environments this p-capture process occurs at a Gamow energy of 10 keV and takes places mainly through a resonant state (Ex = 8.701 MeV) of the compound 11 C nucleus. Thus a resonance right in the region of the Gamow peak is expected to significantly influence the behavior of the astrophysical S(E)-factor. The 10 B(p, α ) 7 Be reaction was studied via the Trojan Horse Method (THM) applied to the 2 H( 10 B, α 7 Be)n in order to extract the astrophysical S(E)-factor in a wide energy range from 5 keV to 1.5 MeV