Heavy Particle Accompanied Fission of 284Og - A Statistical Model Study

The structural characteristics of SHN can be investigated through the decay of SHN. In the present work ternary fission of SHN 284Og for two proton magic fixed third fragment 48Ca and 68Ni is studied at three different excitation energies 20, 35 and 50 MeV. Interestingly, 169Yb + 67Ni + 48Ca is having larger yield values and hence it is the most favoured way of fragmentation at intermediate excitation energy 35 MeV. It is observed that, asymmetric fission is favoured over symmetric fission at all the excitation for the third fragment 48Ca. Asymmetric fission is the most favoured with the fragment combination 148Sm + 68Ni + 68Ni for fixed A3 = 68Ni at all the excitations. Unlike the Ca third fragment, near symmetric fission is also favoured with 113Ag + 103Tc + 68Ni for A3 = 68Ni at all the three excitation energies.

Proton radioactivity of nuclei with atomic numbers Z = 51–91 and mass number 104–211

Proton radioactivity of neutron-deficient nuclei with atomic numbers [Formula: see text]–91 and mass number 104–211 is investigated using the analytical super-asymmetric fission (ASAF) model — a model used to study [Formula: see text]-decay and cluster radioactivity since 1984. The experimental [Formula: see text] values are compared with calculated ones based on WS4 (Y. Z. Wang et al., 2014–2015), and in few cases KTUY05 (H. Koura et al., 2005) mass models. Proton drip-line and neutron drip-line are determined using the WS4 mass model. We compare the calculated results with experimental half-lives, showing good agreement.

Microscopic description of α-decay as super-asymmetric fission

The fine structure of α-decay is treated with fission-like models. The single particle levels are calculated along a least action path connecting the ground state of the parent nucleus and the configuration of two spherical tangent nuclei. The probabilities to find different seniority-1 configurations are obtaining by solving the time-dependent pairing equations generalized by including the Landau-Zener effect and the Coriolis coupling. The theoretical results for the α-decay of 211Po and 211Bi are compared with experimental data showing a good agreement.

Asymmetric crypt fission in colectomy specimens in patients with ulcerative colitis

AimsWe previously found colonic crypts with asymmetric fission bordering regenerating ulcers in ulcerative colitis (UC). The present objective was to assess the frequency of asymmetric crypt-fission in colectomy specimens from patients with long-lasting UC.MethodsH&E-stained sections from seven colectomies from patients with UC without dysplasia or carcinoma were investigated. Symmetric fission was characterised by branched colon crypts showing ≥2 identical crypts, whereas asymmetric fission exhibited branched colon crypt portraying ≥2 dissimilar crypts, differing in diameter, length and/or shape.ResultsThe number of crypts in fission in the 89 sections was 3586; of those, 2930 (81.7%) were asymmetric and the remaining 656 (18.3%), symmetric. Out of 927 vertically-cut crypts (in well-oriented sections), 912 (98.4%) were asymmetric, and the remaining 14 (1.6%), symmetric, and out 2660, cross-cut (transected) crypts in fission, 2018 (75.9%) were asymmetric and the remaining 642 (24.1%), symmetric.ConclusionCrypt fission is rarely found in the normal colon in adults. Symmetric crypt fission found in UC is possibly triggered by a compensatory homeostatic mechanism of crypt production in mucosal areas replaced by chronic inflammation. But asymmetric crypt fission is a pathological aberration that affects crypts in patients with a particular predisposition to develop mucosal dysplasia. It is suggested that this previously unattended histological parameter be included in the pathological descriptions of colectomy specimens from patients with UC.

Cluster Radioactivity

Cluster radioactivity (spontaneous emission of heavy particles from nuclei) is presented from theoretical point of view in good agreement with experimental results. After a brief hystorical account we give details about the analytical super asymmetric fission (ASAF) model extensively used for predicting the half-lives of heavy and superheavy (Z ≥ 104) elements. For the already measured 26 cluster decays (from 14C to 32,34Si of parent nuclides with Z = 87-96) it is clear that cluster radioactivity is a rare phenomenon in the best case about 9 orders of magnitude weaker than the competing alpha decay. Then we show the theoretical possibility of a strong cluster decay compared to alpha decay for some superheavy nuclei with Z ≥ 122, e.g. 306122; 310-314122; 306-324124, and 311-323124.

Asymmetric crypt fission in sessile serrated lesions

ObjectiveSessile serrated lesions without dysplasia (SSL-ND) are epitomised by dilated crypts with epithelial serrations and architectural distortions portraying boot-shapes, L-shapes or inverted-T shapes. Recently, crypts in asymmetric fission were detected in SSL-ND. The purpose was to assess the frequency of crypts in asymmetric fission in a cohort of SSL-ND.MethodsThe frequency of crypts in fission was assessed in 60 SSL-ND, the distribution of cell proliferation in 48 SSL-ND and the expression of maspin, a tumour-suppressor protein, in 29 SSL-ND.ResultsOut of the 60 SSL-ND, 40 (66.7%) showed crypts in fission: 39 (65%) SSL-ND had crypts in asymmetric fission and one SSL-ND (1.7%), in symmetric fission (p<0.05). Of 1495 crypts recorded in the 60 SSL-ND, 73 (4.9%) were in asymmetric fission but only one (0.06%), in symmetric fission (p<0.05). Out of the 48 Ki67-immunostained SSL-ND,15 (31%) showed randomly distributed proliferating cell-domains. All 29 SSL-ND revealed maspin-upregulation (including crypts in asymmetric and symmetric fission). In contrast, the normal colon mucosa showed occasional single crypts in symmetric fission, proliferating cell-domains limited to the lower thirds of the crypts, absence of crypts in asymmetric fission and remained maspin negative.ConclusionsSSL-ND thrive with crypts in asymmetric fission displaying randomly distributed proliferating cell-domains and maspin-upregulation. These histo-biological aberrations disclose pathological cryptogenesis and suggest possibly unfolding somatic mutations in SSL-ND. The present findings may open new vistas on the parameters pertinent to the susceptibility of SSL-ND to develop dysplasia and carcinoma.