Characterization of Hemangioma-initiating Stem Cells

Infantile hemangioma (IH) is the most common vascular tumour of infancy. IH undergoes a unique life cycle consisting of robust endothelial cell proliferation and vessel formation in the proliferating phase, followed by spontaneous regression in the involuting phase. Our laboratory has shown that IH arises from multipotential stem cells termed hemangioma stem cells (HemSCs). However, the phenotype of HemSCs has not been fully elucidated. Here, I examined HemSCs and compared these lesion-derived cells to a panel of normal counterparts. My results show that HemSCs share similar gene expression profiles with human fetal liver-derived stem cells (FLSCs) and postnatal bone marrow mesenchymal/mesodermal progenitor cells (BM-MPCs). Specifically, all three precursor cell types expressed endothelial, mesenchymal, stem/progenitor, and hematopoietic lineage genes to varying degrees. Furthermore, for the first time, I show that proliferating IH lesions are immunoreactive to markers associated with hematopoiesis; namely, RUNX1, GATA2, GPR56, CD45 and CD150. However, HemSCs failed to produce hematopoietic colonies when assessed using in vitro hematopoietic activity assays. Taken together, my studies suggest that HemSCs express hematopoiesis-specific markers but their ability to undergo hematopoiesis is suppressed. Although my findings have provided greater characterization of HemSCs, more studies are needed to fully understand the mechanisms that regulate HemSC differentiation paths, and ultimately IH pathogenesis

Terror Management and the News: An Exploration into the Effects of Framing on Mortality Salience

The present study explores the link between Terror Management Theory and the use of its principles within news media. Political news media in the digital age undergoes a variety of framing effects, more specifically episodic and thematic frames of stories. To induce mortality salience, college-aged participants were presented with stories framed from the perspective of an individual’s experience or a general theme of experiences regarding the controversial pro-life topic and a non-controversial hiking topic. These stories are presented in the style of Instagram posts to mirror how college-aged people consume news media. The stories also contain wording designed to induce mortality salience, creating avenues for worldview defense. Following the presentation of the news stories and a short delay, participants then completed a death thought accessibility measure and a questionnaire about their level of agreement or opposition to the news stories presented, displaying either worldview defense or greater worldview adherence. The results from this experiment show increased worldview defense for participants that viewed the controversial post and no significant differences in the amount of death thoughts present in the conscious, although the non-controversial image had a slightly higher average of death thoughts than the controversial post. The implications of these results are discussed

Violation of the Δ\DeltaI=1/2 rule in the nonmesonic weak decay of Λ\Lambda hypernuclei

Violations of the $\Delta$I=1/2 rule are investigated in the nonmesonic weak hypernuclear decay using a weak $\Lambda$N$\to$NN transition potential based on meson exchange. While the weak $\Delta$I=3/2 matrix elements of baryons with pseudoscalar mesons are known to be very small, the same matrix elements of baryons with vector mesons, evaluated in the factorization approximation, are found to be significant. Within the uncertainties of the factorization approximation we find that the total rate increases by at most 6% lying within the error bars of the more recent experimental result. The neutron- to proton-induced rate, on the other hand, can change by up to a factor of two, while the asymmetry parameter is strongly affected as well.Comment: 17 pages. Paper related to a contribution presented at the International Conference on Hypernuclear and Strange Particle Physics (HYP97). Submitted to Phys. Lett.

Public Awareness of the Nebraska Regional Poison Control Center

A Poison Control Center needs to continually update its impact on the community it serves. At the Nebraska Regional Poison Control Center, a telephone survey was performed to ascertain baseline data for ongoing poison awareness programs. Our data shows that 36.6% of the population would call the PCC in the case of acute poisoning. There is a need to stress that the PCC is not only a center for information but also for treatment at home. Distribution of the PCC phone number to be attached to the phone needs to be increased. Many people obtained the phone number through time consuming methods which would increase the anxiety of the caller. Despite past programs, 63.9% of the respondents were not familiar with Syrup of Ipecac, and overall out of 608, people, 91.1% did not have Syrup of Ipecac at home in case of poisoning. In distributing poison information to the public, the pre-school and other school programs seem to be very effective. Newspapers and television also are an integral part in distributing poison information. With the help of the networks and newspapers in devoting time and space to poison prevention more households can be reached. There is a need to involve the pharmacist in distribution of poison information. Being the major supplier of Syrup of Ipecac, pharmacists can take a more active role by always carrying Syrup of Ipecac, and displaying it so that patrons may be reminded that they should have it at home

Microscopic Approach to Nucleon Spectra in Hypernuclear Non-Mesonic Weak Decay

A consistent microscopic diagrammatic approach is applied for the first time to the calculation of the nucleon emission spectra in the non-mesonic weak decay of Lambda-hypernuclei. We adopt a nuclear matter formalism extended to finite nuclei via the local density approximation, a one--meson exchange weak transition potential and a Bonn nucleon-nucleon strong potential. Ground state correlations and final state interactions, at second order in the nucleon--nucleon interaction, are introduced on the same footing for all the isospin channels of one- and two-nucleon induced decays. Single and double--coincidence nucleon spectra are predicted for 12_Lambda^C and compared with recent KEK and FINUDA data. The key role played by quantum interference terms allows us to improve the predictions obtained with intranuclear cascade codes. Discrepancies with data remain for proton emission.Comment: 11 pages, 6 figures, 2 tables. To be published in Physics Letters

Decay of Hypernuclei

We present a nonrelativistic transition potential for the weak strangeness-changing reaction $\Lambda N \to NN$. The potential is based on a one meson exchange model (OME), where, in addition to the long-ranged pion, the exchange of the pseudoscalar $K, \eta$, as well as the vector $\rho, \omega, K^*$ mesons is considered. Results obtained for different hypernuclear decay observables are compared to the available experimental data.Comment: 8 pages. Invited talk given at the KEK-Tanashi International Symposium on Physics of Hadrons and Nuclei. Tokyo, Japan, December 14-17, 1998. In honor of Prof. K. Yazaki. Submitted to Nucl. Phys. A. LateX file (uses espcrc1.sty

On the effect of the Delta(1232) in hypernuclear non-mesonic weak decay: a microscopic approach

The non-mesonic weak decay of $\Lambda$-hypernuclei is studied within a microscopic diagrammatic approach which includes, for the first time, the effect or the $\Delta$-baryon resonance. We adopt a nuclear matter formalism extended to finite nuclei via the local density approximation, a one-meson exchange weak transition potential, a Bonn nucleon-nucleon strong potential and a $\Delta N\to NN$ strong potential based on the Landau-Migdal theory. Ground state correlations and final state interactions (FSI), at second order in the baryon-baryon strong interaction, are introduced on the same footing for all the isospin channels of one- and two-nucleon induced decays. Weak decay rates and single and double-coincidence nucleon spectra are predicted for $^{12}_\Lambda$C and compared with recent KEK and FINUDA data. The $\Delta(1232)$ introduces new FSI-induced decay mechanisms which lead to an improvement when comparing the obtained nucleon spectra with data, while it turns out to have a negligible effect on the decay rates. Discrepancies with experiment remain only for emission spectra involving protons, but are mostly restricted to double-nucleon correlations in the non-back-to-back kinematics.Comment: 11 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1103.227

Nonmesonic Weak Decay of Λ\Lambda Hypernuclei within a Nuclear Matter Formalism

The nonmesonic weak decay of $\Lambda$ hypernuclei using nonrelativistic nuclear matter is studied. As the basic building block we use the Polarization Propagator Method developed by Oset and Salcedo. It is shown that the exact calculation of exchange terms is required. Using the Local Density Approximation we evaluate the nonmesonic decay width for $^{12}_{\Lambda}C$ and compare the result with a finite nucleus calculation, obtaining a qualitative agreement.Comment: 28 pages, 3 figure

Quantum interference terms in nonmesonic weak decay of Λ\Lambda-hypernuclei within a RPA formalism

Single and double coincidence nucleon spectra in the $\Lambda$-hypernuclei weak decay are evaluated and discussed using a microscopic formalism. Nuclear matter is employed together with the local density approximation which allows us to analyze the $^{12}_{\Lambda}C$ hypernucleus non-mesonic weak decay. Final state interactions (FSI) are included via the first order (in the nuclear residual interaction) terms to the RPA, where the strong residual interaction is modelled by a Bonn potential. At this level of approximation, these FSI are pure quantum interference terms between the primary decay $(\Lambda N \to NN)$ and $(\Lambda N \to NN \to NN)$, where the strong interaction is responsible for the last piece in the second reaction. Also the Pauli exchange contributions are explicitly evaluated. We show that the inclusion of Pauli exchange terms is important. A comparison with data is made. We conclude that the limitations in phase space in the RPA makes this approximation inadequate to reproduce the nucleon spectra. This fact, does not allow us to draw a definite conclusion about the importance of the interference terms.Comment: 39 pages, 10 figure

Neutron and proton spectra from the decay of Λ\Lambda hypernuclei

We have determined the spectra of neutrons and protons following the decay of $\Lambda$ hypernuclei through the one- and two-nucleon induced mechanisms. The momentum distributions of the primary nucleons are calculated and a Monte Carlo simulation is used to account for final state interactions. From the spectra we calculate the number of neutrons ($N_n$) and protons ($N_p$) per $\Lambda$ decay and show how the measurement of these quantities, particularly $N_p$, can lead to a determination of $\Gamma_n / \Gamma_p$, the ratio of neutron to proton induced $\Lambda$ decay. We also show that the consideration of the two-nucleon induced channel has a repercussion in the results, widening the band of allowed values of $\Gamma_n / \Gamma_p$ with respect to what is obtained neglecting this channel.Comment: 30 pages, 12 Postscript figures, uuencoded file, ReVTeX, epsf.st