Hard X-ray, quantitative, fluorescence elemental imaging was performed on the ID22NI nanoprobe and ID22 microprobe beam lines of the European Synchrotron Research facility (ESRF) in Grenoble, France, on eight interstellar candidate impact features in the framework of the NASA Stardust Interstellar Preliminary Examination (ISPE). Three features were unambiguous tracks, and the other five were identified as possible, but not definite, impact features. Overall, we produced an absolute quantification of elemental abundances in the 15 <= Z <= 30 range by means of corrections of the beam parameters, reference materials, and fundamental atomic parameters. Seven features were ruled out as interstellar dust candidates (ISDC) based on compositional arguments. One of the three tracks, I1043,1,30,0,0, contained, at the time of our analysis, two physically separated, micrometer-sized terminal particles, the most promising ISDCs, Orion and Sirius. We found that the Sirius particle was a fairly homogenous Ni-bearing particle and contained about 33 fg of distributed high-Z elements (Z > 12). Orion was a highly heterogeneous Fe-bearing particle and contained about 59 fg of heavy elements located in hundred nanometer phases, forming an irregular mantle that surrounded a low-Z core. X-ray diffraction (XRD) measurements revealed Sirius to be amorphous, whereas Orion contained partially crystalline material (Gainsforth et al. 2014). Within the mantle, one grain was relatively Fe-Ni-Mn-rich; other zones were relatively Mn-Cr-Ti-rich and may correspond to different spinel populations. For absolute quantification purposes, Orion was assigned to a mineralogical assemblage of forsterite, spinel, and an unknown Fe-bearing phase, while Sirius was most likely composed of an amorphous Mg-bearing material with minor Ni and Fe. Owing to its nearly chondritic abundances of the nonvolatile elements Ca, Ti, Co, and Ni with respect to Fe, in combination with the presence of olivine and spinel as inferred from XRD measurements, Orion had a high probability of being extraterrestrial in origin.

Perfluoroalkyl substances (PFAS) represent a family of environmental toxicants that have infiltrated the living world. This study explores diet-PFAS interactions and the impact of perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic (PFHxS) on the hepatic proteome and blood lipidomic profiles. Male C57BL/6J mice were fed with either a low-fat diet (10.5% kcal from fat) or a high fat (58% kcal from fat) high carbohydrate (42 g/l) diet with or without PFOS or PFHxS in feed (0.0003% wt/wt) for 29 weeks. Lipidomic, proteomic, and gene expression profiles were determined to explore lipid outcomes and hepatic mechanistic pathways. With administration of a high-fat high-carbohydrate diet, PFOS and PFHxS increased hepatic expression of targets involved in lipid metabolism and oxidative stress. In the blood, PFOS and PFHxS altered serum phosphatidylcholines, phosphatidylethanolamines, plasmogens, sphingomyelins, and triglycerides. Furthermore, oxidized lipid species were enriched in the blood lipidome of PFOS and PFHxS treated mice. These data support the hypothesis that PFOS and PFHxS increase the risk of metabolic and inflammatory disease induced by diet, possibly by inducing dysregulated lipid metabolism and oxidative stress.

RNAi and single-cell RNA-seq characterize the mechanism of endosymbiosis between coral and dinoflagellates.

MotivationComputational inference of genome organization based on Hi-C sequencing has greatly aided the understanding of chromatin and nuclear organization in three dimensions (3D). However, existing computational methods fail to address the cell population heterogeneity. Here we describe a probabilistic-modeling-based method called CscoreTool-M that infers multiple 3D genome sub-compartments from Hi-C data.ResultsThe compartment scores inferred using CscoreTool-M represents the probability of a genomic region locating in a specific sub-compartment. Compared to published methods, CscoreTool-M is more accurate in inferring sub-compartments corresponding to both active and repressed chromatin. The compartment scores calculated by CscoreTool-M also help to quantify the levels of heterogeneity in sub-compartment localization within cell populations. By comparing proliferating cells and terminally differentiated non-proliferating cells, we show that the proliferating cells have higher genome organization heterogeneity, which is likely caused by cells at different cell-cycle stages. By analyzing 10 sub-compartments, we found a sub-compartment containing chromatin potentially related to the early-G1 chromatin regions proximal to the nuclear lamina in HCT116 cells, suggesting the method can deconvolve cell cycle stage-specific genome organization among asynchronously dividing cells. Finally, we show that CscoreTool-M can identify sub-compartments that contain genes enriched in housekeeping or cell-type-specific functions.

The mineral record contains chemical signatures that reflect the evolving redox conditions of Earth's crust, and reveal trends in the bioavailability of life's critical elements. In particular, shifting redox states of transition metal elements that are used as co-factors by enzymes across all domains of life can be tracked in preserved mineral chemistry. The transition metal iron (Fe) is one of the most abundant elements in Earth's core, mantle, and crust, and is commonly a major constituent of rock-forming minerals. Additionally, Fe is the most widely used metal in biology, and Earth's redox history has profoundly impacted the chemical speciation and availability of Fe in aqueous systems. The diverse mineral chemistry of Fe can therefore reveal new insights into the redox evolution of Earth's crust and subsequent biological impacts. Here, we apply a new mineral chemistry network analysis platform, dragon, to investigate the mineral chemistry of iron (Fe) over geologic-time. We present bipartite network graphs of iron minerals linked to their constituent elements or ions for several geological time intervals. These graphs illustrate the increasing importance of oxygen (O) abundance in the atmosphere from the Paleoarchean to the Mesoproterozoic in regard to the the emergence of new Fe minerals, as well as the influence of free O on trends in element electronegativity in mineral formation and electron transfer processes. The proportion of oxygen containing Fe minerals had the sharpest increase during the time periods of the Kenorland and Columbia supercontinent assembly events. Indeed, the rise of O is associated with O becoming more centralized in the network as well as with an increase through time in the number of Fe minerals containing combinations of high and low electronegativity elements. The importance of oxygen in the expansion of Fe mineral chemical diversity, and its influence on the bioavailability of Fe in the environment, is illustrated clearly in the Fe mineral chemistry network.

The heat extracted from the core by the overlying mantle across the core-mantle boundary controls the thermal evolution of the core. This in turn leads to the solidification of the inner core in association with the exsolution of light alloying elements into the liquid outer core. Although the temperature (T) at the inner core boundary (ICB) would be adjusted to account for the effects of the light elements, the melting T of Fe places an upper bound at the ICB and it is a vital point in the thermal profile of the core. Here, we determine the melting T of Fe in the multi-anvil press by characterizing the interface of Fe-W interaction. Our data place a tighter constraint on the melting curve of Fe between 8 and 21 GPa, that is directly applicable to small planetary bodies and serves as an anchor for melting curve of Fe at higher pressure.

New Raman and NMR spectroscopy data on hydrous Ca aluminosilicate melts and glasses, with eutectic quartz-anorthite-wollastonite composition, are presented here. The glasses were obtained by rapid quench of melts equilibrated at high P and high T in a piston-cylinder apparatus. In situ Raman observations of the structure of the melts were also performed during hydrothermal diamond cell experiments. Using the intensities of the similar to 860 cm(-1) and similar to 1630 cm(-1) Raman signals, respectively assigned to vibrations of T-OH and H2Omol species, we determined the speciation of water in the glasses. T-OH and H2Omol values compare well with those determined from infrared (IR) spectra, except above similar to 5 wt% total water where IR determinations actually underestimate the proportion of hydroxyl groups. The analysis of the polarized Raman spectra and of the Si-29 MAS NMR spectra of the hydrous glasses suggests limited changes in glass polymerization with variations in dissolved water content. However, at high temperatures, in situ Raman spectroscopy observations indicate that the hydrous melt structure differs very strongly from that of a glass containing a comparable concentration of dissolved water. Because of this, this study reinforces the fact that using glass data to try understanding high temperature processes in hydrous melts, like viscous flow or water diffusion toward bubbles during volcanic degassing, may not be very appropriate.