The available body of informa1ion on (a) fluorescence, Auger, and Coster-Kronig yields. (b) radiative and radiationless 1ransition rates, (c) level widths, (d) x-ray and Auger line widths, (e) x-ray and Auger spectra. and (f) Coster-Kronig energies has been used to generate an internally consistent set of values of a10mic radiative and radiationless yields for the K shell (5 :5 Z :5 no) and the L subshells (12 :5 Z :5 110). Values of fluorescence yields WK. WIo W 2 , W: l , Coster-Kronig yields fl. fl.2, fl.:!' f' 1.:$' j~.:l' Auger yields aK, U I' a2' a:l. and effective l1uoresence yields 1'1 and V 2 are presented in tables and graphs. Estimates of uncertain1ies are given. Lpdated and expanded graphs of partial and total widths of K, L I • L 2 • and L., levels are presented as well as a reference list of napers published since abou1 1972.

Semi-empiricalv8.Iues of the natural widths of K, L I' L2 and L:l levels, Kat and Kaz x-ray lines, and KL~l' KL~2 and KL~3 Auger lines for the dements 10 :s: Z :s: 110 are presented in tables and graphs. Level width fi (i = K, L 1 , L 2 , L 3) is obtained from the relation r i = rn,;lw;, using the the•oretical radiative rate rl{.i from Scofield's relativistic, relaxed Hartree-Fock calculation and the fluorescence yield Wi from Krause's evaluation. X-ray and Auger line widths are calculated as the sums of pertinent level widths. This tabulation of natural level and line widths is internally consistent, and is compatible with all relevant experimental and theoretical informatibn. Present semi-empirical widths, especially those of Ka 1 and Kaz x-rays, are compared with measured widths. Uncertainties of semi-empirical values are estimated.

Pluripotency, the ability to generate any cell type of the body, is an evanescent attribute of embryonic cells. Transitory pluripotent cells can be captured at different time points during embryogenesis and maintained as embryonic stem cells or epiblast stem cells in culture. Since ontogenesis is a dynamic process in both space and time, it seems counterintuitive that these two temporal states represent the full spectrum of organismal pluripotency. Here we show that by modulating culture parameters, a stem-cell type with unique spatial characteristics and distinct molecular and functional features, designated as region-selective pluripotent stem cells (rsPSCs), can be efficiently obtained from mouse embryos and primate pluripotent stem cells, including humans. The ease of culturing and editing the genome of human rsPSCs offers advantages for regenerative medicine applications. The unique ability of human rsPSCs to generate post-implantation interspecies chimaeric embryos may facilitate our understanding of early human development and evolution.

Relative abundances of differently charged ions were measured following the x irradiation of Xe, and, in separate experiments, of Hg. These studies were carried out for a variety of x-ray energies in order to obtain data as a function of the initial inner-shell vacancies. From the data we have derived charge spectra that result from producing an initial vacancy in each of the following shells: the K, L\, Xii,iu, M\, -M"II,III, Miv,v, and N shells of Xe; and the L, M, N, and 0 shells of Hg. These data are correlated with earlier measurements on He, Ne, Ar, and Kr; and empirical rules are set up whereby one may estimate the average charge resulting from the atomic readjustment to a vacancy in any shell of any atom. 42 CARLSON,HUNT, AND KRAUSE

SUMMARY Heart failure is a leading cause of mortality and morbidity in the developed world, partly because mammals lack the ability to regenerate heart tissue. Whether this is due to evolutionary loss of regenerative mechanisms present in other organisms or to an inability to activate such mechanisms is currently unclear. Here, we decipher mechanisms underlying heart regeneration in adult zebrafish and show that the molecular regulators of this response are conserved in mammals. We identified miR-99/100 and Let-7a/c, and their protein targets smarca5 and fntb, as critical regulators of cardiomyocyte dedifferentiation and heart regeneration in zebrafish. Although human and murine adult cardiomyocytes fail to elicit an endogenous regenerative response following myocardial infarction, we show that in vivo manipulation of this molecular machinery in mice results in cardiomyocyte dedifferentiation and improved heart functionality after injury. These data provide a proof-of-concept for identifying and activating conserved molecular programs to regenerate the damaged heart.

Background Long noncoding RNAs (lncRNAs) have emerged as critical epigenetic regulators with important functions in development and disease. Here, we sought to identify and functionally characterize novel lncRNAs critical for vertebrate development. Methods and Results By relying on human pluripotent stem cell differentiation models, we investigated lncRNAs differentially regulated at key steps during human cardiovascular development with a special focus on vascular endothelial cells. RNA sequencing led to the generation of large data sets that serve as a gene expression roadmap highlighting gene expression changes during human pluripotent cell differentiation. Stage-specific analyses led to the identification of 3 previously uncharacterized lncRNAs, TERMINATOR, ALIEN, and PUNISHER, specifically expressed in undifferentiated pluripotent stem cells, cardiovascular progenitors, and differentiated endothelial cells, respectively. Functional characterization, including localization studies, dynamic expression analyses, epigenetic modification monitoring, and knockdown experiments in lower vertebrates, as well as murine embryos and human cells, confirmed a critical role for each lncRNA specific for each analyzed developmental stage. Conclusions We have identified and functionally characterized 3 novel lncRNAs involved in vertebrate and human cardiovascular development, and we provide a comprehensive transcriptomic roadmap that sheds new light on the molecular mechanisms underlying human embryonic development, mesodermal commitment, and cardiovascular specification.

No abstract

A double-focusing electrostatic electron spectrometer has been used to measure the K—LL Auger spectra resulting from electron impact for each of the elements in the gaseous molecules N2, O2, CO, NO, H2O, and CO2. An energy resolution of 0.09% full width half-maximum was normally employed. A method for analyzing these complex spectra is described. It involves the identification of normal and satellite lines. The former are defined as arising from single electron ionization from the K shell without additional excitation followed by an Auger process in which one electron fills the vacancy while a second goes into the continuum, and where all the other electrons remain in their same orbitals. Satellite lines result when extra excitation occurs either in the initial formation of the K vacancy or in the subsequent Auger process. To aid in the identification of these satellite lines, auxiliary experiments have been performed such as the study of discrete energy losses in photoionization due to electron shake-up, and the comparison of Auger spectra produced by monoenergetic x rays. As a consequence of the analyses of the Auger spectra, information has been obtained on (1) the nature of initial excitation processes such as the transition of a K electron into excited discrete states and monopole excitation and (2) the identification of the energy and nature of the ground and excited states of the doubly charged molecular ions. The second ionization potential was obtained for each of the molecules, and in one case, N2, the third ionization potential was estimated. Finally, a brief discussion is made of the possible use of high resolution electron spectroscopy in molecular as well as elemental analysis.