Common Exposure to STL Polyomavirus During Childhood

STL polyomavirus (STLPyV) was recently identified in human specimens. To determine seropositivity for STLPyV, we developed an ELISA and screened patient samples from 2 US cities (Denver, Colorado [500]; St. Louis, Missouri [419]). Overall seropositivity was 68%–70%. The age-stratified data suggest that STLPyV infection is widespread and commonly acquired during childhood.     

Cancer Survivors’ Use of Numerous Information Sources for Cancer-Related Information: Does More Matter?

A large proportion of the 14 million cancer survivors in the USA are actively seeking health information. This study builds on the informed- and shared-decision making literature, examining cancer survivors’ health information seeking behaviors to (1) quantify the number of health information sources used; (2) create a demographic profile of patients who report seeking cancer information from numerous sources versus fewer sources in five areas: cancer information overall, disease/treatment, self-care/management, health services, and work/finances; and (3) examine whether seeking cancer information from numerous sources is associated with self-efficacy, fear of recurrence, perceptions of information seeking difficulty, and resultant patient–provider communication. Data came from a survey of post-treatment cancer survivors (N?=?501) who responded to a mailed questionnaire about health information seeking. Participants were divided into two groups using a median split: those who sought health information from more than five sources (numerous source seekers) and those that sought information from less than five sources (fewer source seekers). Multivariable logistic regression was used to model differential information seeking behaviors and outcomes for numerous versus fewer source seekers. On average, survivors sought cancer-related information from five different sources. Numerous source seekers were more likely to be women, have higher levels of education, and report fewer problems with cancer information-seeking. Overall, numerous source seekers were no more or less likely to discuss information with their providers or bring conflicting information to their providers. Understanding the characteristics, behaviors, and experiences of survivors who seek cancer-related information from numerous sources can contribute to informed decision making and patient-centered care.     

Early volatile depletion on planetesimals inferred from C–S systematics of iron meteorite parent bodies

During the formation of terrestrial planets, volatile loss may occur through nebular processing, planetesimal differentiation, and planetary accretion. We investigate iron meteorites as an archive of volatile loss during planetesimal processing. The carbon contents of the parent bodies of magmatic iron meteorites are reconstructed by thermodynamic modeling. Calculated solid/molten alloy partitioning of C increases greatly with liquid S concentration, and inferred parent body C concentrations range from 0.0004 to 0.11 wt%. Parent bodies fall into two compositional clusters characterized by cores with medium and low C/S. Both of these require significant planetesimal degassing, as metamorphic devolatilization on chondrite-like precursors is insufficient to account for their C depletions. Planetesimal core formation models, ranging from closed-system extraction to degassing of a wholly molten body, show that significant open-system silicate melting and volatile loss are required to match medium and low C/S parent body core compositions. Greater depletion in C relative to S is the hallmark of silicate degassing, indicating that parent body core compositions record processes that affect composite silicate/iron planetesimals. Degassing of bare cores stripped of their silicate mantles would deplete S with negligible C loss and could not account for inferred parent body core compositions. Devolatilization during small-body differentiation is thus a key process in shaping the volatile inventory of terrestrial planets derived from planetesimals and planetary embryos.

Major volatiles (H, C, N, and S) are inherently plentiful in the interstellar medium and abundant in primitive carbonaceous chondrites (CCs) (1, 2), but are scarce in terrestrial planets, which gained most of their mass from the inner parts of the solar nebula (3, 4). Formation of volatile-poor planets from a volatile-rich protoplanetary disk is a result of processes in the solar nebula, in accretion of precursor solids, and in interior differentiation. Addition of volatiles to nascent planets varies during accretion as protoplanetary systems become dynamically excited, contributing material originating from different heliocentric distances (3) and with different thermal histories. Much of this mass arrives in larger bodies (planetesimals or planetary embryos) that differentiated soon after formation (5). Key uncertainties include the nebular history of bulk materials that contributed volatiles to the rocky planets and how that affected their volatile cargos (6), and how planetesimal and planet formation influenced volatile distributions in accreted parent bodies.Processes responsible for volatile deficits in terrestrial planets (7, 8) can occur either in the nebular, planetesimal, or planetary environment. Nebular volatile depletion could result from chemical interactions between nebular gas and dust, chondrule formation, or the accretion of thermally processed solids (9–11), perhaps owing to the hotter conditions prevailing closer to the protosun (4). Li et al. (6) argue that the comparatively small C inventory of the bulk Earth requires that nebular materials experienced significant early (<1 Ma) heating, before the “soot line” moved inward of 1 AU. Planetesimal processes involve loss to space during differentiation or processing of intermediate-sized bodies of tens to hundreds of kilometers in diameter (e.g., refs. 12 and 13). Planetary loss processes occur on large (thousands of kilometers in diameter) bodies (14, 15) in which gravity plays an appreciable role—including loss from impacts (16). The sum of these is an important determinant for whether terrestrial planets form with volatiles sufficient for habitability but not so great as to become ocean worlds (17) or greenhouse hothouses (18).A key goal in the study of exoplanets and of young stellar systems is predicting environments and processes that could lead to habitable planets, including development of models that account for the distribution, acquisition, and loss of key volatile elements. Astronomical studies can reveal the architecture of other solar systems (19), the compositions of observable exoplanet atmospheres (ref. 20 and references therein), and the dust and volatile gas structure and composition of protoplanetary disks (ref. 21 and references therein), including interactions of the disk with gas- or ice-giant protoplanets. However, only limited astronomical observations can be made about conversion of disk materials (gas, dust, and pebbles) to planets in other solar systems. To understand this conversion, we must necessarily rely on planetesimals and their remnants (meteorites) as records of the processes that occurred. In this paper, we focus on volatile loss during planetesimal differentiation by examining evidence chiefly from iron meteorites. We note that ephemeral metal enrichments in white dwarf atmospheres confirm that differentiated planetesimals are common around other stars (22), and that our findings apply to how materials would have been processed during the assembly of other planetary systems.In classic oligarchic growth models of planetary origin, planets and embryos grow from accretion of planetesimals with characteristic radii of tens to a few hundreds of kilometers (3). In pebble accretion models of terrestrial planet formation, the fraction of planetesimals in accreting material varies with time and protoplanetary mass (23), but still remains significant. Thus, for understanding volatile delivery to growing planets, an important question is whether the volatile inventory of accreting planetesimals (or larger objects) remained similar to that of primitive materials, typically taken to be comparable to chondritic meteorites, or had diminished significantly from prior differentiation.^*Achondritic meteorites are fragments of differentiated planetesimals and provide direct evidence of processes on small bodies.^† Evidence for volatile loss on silicate achondritic parent bodies comes from elemental concentrations and from isotopes (24–27). However, the best-studied silicate achondritic suites, such as the eucrites and angrites, are igneous crustal rocks (28), and their compositions may not reflect average major volatile contents of their parent bodies. Volatile loss could have been locally enhanced by the igneous activity that produced the planetesimal crusts (29).Iron meteorites offer an additional record of volatile processing in planetesimals. Many, known as “magmatic” irons, originated as metallic cores of planetesimals (30) and potentially record volatile depletions in their parent planetesimals at the time of alloy–silicate separation. Iron meteorites contain measurable amounts both major (S, C, N) and moderately volatile (Ge, Ga) elements and represent the cores of at least 50 parent bodies (31). Thus, known parent body cores are likely survivors from a population of planetesimals that were mostly incorporated into larger bodies and planets. Additionally, isotopic evidence links iron meteorites with both carbonaceous (CC) and noncarbonaceous (NC) chondrites (32), thereby correlating the differentiated planetesimals to their primitive chondritic heritage.Here, we address the problem of planetesimal volatile loss by focusing on carbon and sulfur, two siderophile volatile elements that give important clues to the degassing history of metallic cores recorded iron meteorites and thereby their parent planetesimals.^‡ We begin by examination of C–S systematics in different classes of chondrites. Although chondritic parent bodies formed later than most parent bodies of iron meteorites (33), they provide the best available guide to undifferentiated materials in the early solar system. Their isotopic kinships to iron meteorites (32) suggest that they derive from similar, although not necessarily identical, reservoirs, and so they provide a basis for comparison to those estimated for parent body cores. They also reveal devolatilization processes associated with planetesimal metamorphism. We then examine iron meteorite groups and reconstruct the compositions of their respective parent cores. Finally, we consider a spectrum of simple planetesimal core-formation scenarios and model the resulting C and S distributions. Comparison of these to reconstructed parent core C and S places new constraints on the magnitude of degassing occurring from planetesimal interiors.