Search for Multifragmentation Near Threshold in the 3-He + Ag Reaction

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Multifragment Emission in the 3-He + nat-Hg Reaction at 0.90 and 3.6 GeV

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited

This report is a review of Darwin's classical theory of bodily tides in which we present the analytical expressions for the orbital and rotational evolution of the bodies and for the energy dissipation rates due to their tidal interaction. General formulas are given which do not depend on any assumption linking the tidal lags to the frequencies of the corresponding tidal waves (except that equal frequency harmonics are assumed to span equal lags). Emphasis is given to the cases of companions having reached one of the two possible final states: (1) the super-synchronous stationary rotation resulting from the vanishing of the average tidal torque; (2) the capture into a 1:1 spin-orbit resonance (true synchronization). In these cases, the energy dissipation is controlled by the tidal harmonic with period equal to the orbital period (instead of the semi-diurnal tide) and the singularity due to the vanishing of the geometric phase lag does not exist. It is also shown that the true synchronization with non-zero eccentricity is only possible if an extra torque exists opposite to the tidal torque. The theory is developed assuming that this additional torque is produced by an equatorial permanent asymmetry in the companion. The results are model-dependent and the theory is developed only to the second degree in eccentricity and inclination (obliquity). It can easily be extended to higher orders, but formal accuracy will not be a real improvement as long as the physics of the processes leading to tidal lags is not better known.Comment: 30 pages, 7 figures, corrected typo

Multifragmentation of 197-Au by 5.0 - 14.6 GeV/c Proton and pi- Beams

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Identification of clonal hematopoiesis mutations in solid tumor patients undergoing unpaired next-generation sequencing assays

Purpose: In this era of precision-based medicine, for optimal patient care, results reported from commercial next-generation sequencing (NGS) assays should adequately reflect the burden of somatic mutations in the tumor being sequenced. Here, we sought to determine the prevalence of clonal hematopoiesis leading to possible misattribution of tumor mutation calls on unpaired Foundation Medicine NGS assays. Experimental Design: This was a retrospective cohort study of individuals undergoing NGS of solid tumors from two large cancer centers. We identified and quantified mutations in genes known to be frequently altered in clonal hematopoiesis (DNMT3A, TET2, ASXL1, TP53, ATM, CHEK2, SF3B1, CBL, JAK2) that were returned to physicians on clinical Foundation Medicine reports. For a subset of patients, we explored the frequency of true clonal hematopoiesis by comparing mutations on Foundation Medicine reports with matched blood sequencing. Results: Mutations in genes that are frequently altered in clonal hematopoiesis were identified in 65% (1,139/1,757) of patients undergoing NGS. When excluding TP53, which is often mutated in solid tumors, these events were still seen in 35% (619/1,757) of patients. Utilizing paired blood specimens, we were able to confirm that 8% (18/226) of mutations reported in these genes were true clonal hematopoiesis events. The majority of DNMT3A mutations (64%, 7/11) and minority of TP53 mutations (4%, 2/50) were clonal hematopoiesis. Conclusions: Clonal hematopoiesis mutations are commonly reported on unpaired NGS testing. It is important to recognize clonal hematopoiesis as a possible cause of misattribution of mutation origin when applying NGS findings to a patient's care

Investigating the effects of vitreous humour (crude extract) on growth and differentiation of rat mesenchymal stem cells (rMSCs) and human NTERA2 cells

It is very well documented that retinoic acid (RA) reduces growth rate by induction of cell differentiation in certain conditions and cell lines. On the other hand, hyaluronic acid (HA) is known for its growth induction on cultured cells. A natural source of HA, rabbit vitreous humour (VH), was previously shown to promote wound repair in model animals. In search for its possible mechanisms, VH extract was tested on the cultured mesenchymal stem cells and NTERA2 as human embryonal carcinoma cells in the presence of RA. Changes in some cellular and molecular markers (A2B5, Oct4, Sox2) showed that VH and possibly HA interfere with differentiating effects of RA. Therefore, this reagent may affect cell proliferation and tissue regeneration by inhibition of cell differentiation.Хорошо известно, что ретиноевая кислота (RA) снижает темпы роста, индуцируя дифференциацию клеточных линий в определенных условиях. Вместе с тем известно, что гиалуроновая кислота (HA) индуцирует рост культивируемых клеток. Ранее было показано, что естественный источник НА, стекловидное тело (VH) кролика, вызывает заживление ран у модельных животных. В поисках возможного механизма этого процесса экстракт стекловидного тела был исследован на культивируемых мезенхимальных стволовых клетках и клетках NTERA2 эмбриональной карциномы человека в присутствии RA. Изменения некоторых клеточных и молекулярных маркеров (A2B5, Oct4, Sox2) показали, что VH и, возможно, HA влияют на дифференцирующие эффекты RA. Таким образом, это вещество может влиять на пролиферацию клеток и регенерацию тканей, ингибируя дифференциацию клеток.Добре відомо, що ретиноєва кислота (RA) знижує темпи росту, індукуючи диференціацію кліткових ліній в певних умовах. Разом з тим відомо, що гіалуронова кислота (НА) індукує ріст культиво- ваних клітин. Раніше було показано, що природне джерело НА, склоподібне тіло (VH) кроля, викликає загоєння ран у модельних тварин. В пошуках можливого механізму цього процесу екстракт склоподібного тіла був досліджений на культивованих мезенхімальних стовбурових клітинах та клітинах NTERA2 ембріональної карциноми людини в присутності RA. Зміни деяких клітинних та молекулярних маркерів (A2B5, Oct4, Sox2) показали, що VH і, можливо, НА впливають на диференціюючі ефекти RA. Таким чином, ця речовина може впливати на проліферацію і регенерацію тканин, інгібуючи диференціацію клітин

Light-Ion-Induced Multifragmentation: The ISiS Project

An extensive study of GeV light-ion-induced multifragmentation and its possible interpretation in terms of a nuclear liquid-gas phase transition has been performed with the Indiana Silicon Sphere (ISiS)4 pi detector array. Measurements were performed with 5-15 GeV/c p, pbar, and pion beams incident on $^{197}$Au and 2-5 GeV $^3$He incident on $^{nat}$Ag and $^{197}$Au targets. Both the reaction dynamics and the subsequent decay of the heavy residues have been explored. The data provide evidence for a dramatic change in the reaction observables near an excitation energy of E*/A = 4-5 MeV per residue nucleon. In this region, fragment multiplicities and energy spectra indicate emission from an expanded/dilute source on a very short time scale (20-50 fm/c). These properties, along with caloric curve and scaling-law behavior, yield a pattern that is consistent with a nuclear liquid-gas phase transition.Comment: 67 pages, 44 figures, all included in tar fil