Low 60Fe abundance in Semarkona and Sahara 99555

Iron-60 (t1/2=2.62 Myr) is a short-lived nuclide that can help constrain the astrophysical context of solar system formation and date early solar system events. A high abundance of 60Fe (60Fe/56Fe= 4x10-7) was reported by in situ techniques in some chondrules from the LL3.00 Semarkona meteorite, which was taken as evidence that a supernova exploded in the vicinity of the birthplace of the Sun. However, our previous MC-ICPMS measurements of a wide range of meteoritic materials, including chondrules, showed that 60Fe was present in the early solar system at a much lower level (60Fe/56Fe=10-8). The reason for the discrepancy is unknown but only two Semarkona chondrules were measured by MC-ICPMS and these had Fe/Ni ratios below ~2x chondritic. Here, we show that the initial 60Fe/56Fe ratio in Semarkona chondrules with Fe/Ni ratios up to ~24x chondritic is 5.4x10-9. We also establish the initial 60Fe/56Fe ratio at the time of crystallization of the Sahara 99555 angrite, a chronological anchor, to be 1.97x10-9. These results demonstrate that the initial abundance of 60Fe at solar system birth was low, corresponding to an initial 60Fe/56Fe ratio of 1.01x10-8.Comment: The Astrophysical Journal, in press. 28 pages, 2 tables, 3 figure

In search of the Earth-forming reservoir: Mineralogical, chemical, and isotopic characterizations of the ungrouped achondrite NWA 5363/NWA 5400 and selected chondrites

High-precision isotope data of meteorites show that the long-standing notion of a “chondritic uniform reservoir” is not always applicable for describing the isotopic composition of the bulk Earth and other planetary bodies. To mitigate the effects of this “isotopic crisis” and to better understand the genetic relations of meteorites and the Earth-forming reservoir, we performed a comprehensive petrographic, elemental, and multi-isotopic (O, Ca, Ti, Cr, Ni, Mo, Ru, and W) study of the ungrouped achondrites NWA 5363 and NWA 5400, for both of which terrestrial O isotope signatures were previously reported. Also, we obtained isotope data for the chondrites Pillistfer (EL6), Allegan (H6), and Allende (CV3), and compiled available anomaly data for undifferentiated and differentiated meteorites. The chemical compositions of NWA 5363 and NWA 5400 are strikingly similar, except for fluid mobile elements tracing desert weathering. We show that NWA 5363 and NWA 5400 are paired samples from a primitive achondrite parent-body and interpret these rocks as restite assemblages after silicate melt extraction and siderophile element addition. Hafnium-tungsten chronology yields a model age of 2.2 ± 0.8 Myr after CAI, which probably dates both of these events within uncertainty. We confirm the terrestrial O isotope signature of NWA 5363/NWA 5400; however, the discovery of nucleosynthetic anomalies in Ca, Ti, Cr, Mo, and Ru reveals that the NWA5363/NWA 5400 parent-body is not the “missing link” that could explain the composition of the Earth by the mixing of known meteorites. Until this “missing link” or a direct sample of the terrestrial reservoir is identified, guidelines are provided of how to use chondrites for estimating the isotopic composition of the bulk Earth

Early on-treatment plasma interleukin-18 as a promising indicator for long-term virological response in patients with HIV-1 infection

Background and aimsIt is necessary to identify simple biomarkers that can efficiently predict the efficacy of long-term antiretroviral therapy (ART) against human immunodeficiency virus (HIV), especially in underdeveloped countries. We characterized the dynamic changes in plasma interleukin-18 (IL-18) and assessed its performance as a predictor of long-term virological response.MethodsThis was a retrospective cohort study of HIV-1-infected patients enrolled in a randomized controlled trial with a follow-up of 144  weeks of ART. Enzyme-linked immunosorbent assay was performed to evaluate plasma IL-18. Long-term virological response was defined as HIV-1 RNA <20 copies/mL at week 144.ResultsAmong the 173 enrolled patients, the long-term virological response rate was 93.1%. Patients with a long-term virological response had significantly lower levels of week 24 IL-18 than non-responders. We defined 64  pg./mL, with a maximum sum of sensitivity and specificity, as the optimal cutoff value of week 24 IL-18 level to predict long-term virological response. After adjusting for age, gender, baseline CD4+ T-cell count, baseline CD4/CD8 ratio, baseline HIV-1 RNA level, HIV-1 genotype and treatment strategy, we found that lower week 24 IL-18 level (≤64 vs. >64 pg./mL, a OR 19.10, 95% CI: 2.36–154.80) was the only independent predictor of long-term virological response.ConclusionEarly on-treatment plasma IL-18 could act as a promising indicator for long-term virological response in patients with HIV-1 infection. Chronic immune activation and inflammation may represent a potential mechanism; further validation is necessary

Replication Data for: ds01

The dataset to calculate the ratio of Jnet/Jevap for K as a function of time and size of the evaporating body at 1800K and a total pressure of 2x10-7 bar in Figure 1A following Equation (4) and (5). Jevap is calculated using the evaporation code described by Young et al. (2019) and in the text. After ~ 4 days, the ratio of Jnet/Jevap for K approached 0.001 and the saturation thereby is close to 99.9% for the body with the radius of 500 km. 1000 km, and Moon’s radius (1700 km)

Datasets for: Escape from a transient rock vapor atmosphere as the mechanism for fractionation of the Moon’s moderately volatile elements.

In this supporting file we describe the captions of eleven datasets that we used for plotting the Figure 1 to 12 in the manuscript. The equations and parameters have been demonstrated in the text. Since this is a modeling paper, we do not collect or create any original data. All the data used in the datasets are referred to previous publications, which have been cited in the manuscript and references

Gray Relevance Algorithm Based Routing Protocol in Ad Hoc Network

The characteristics of nodes moving arbitrarily and the network topology changing frequently lead to AODV routing protocol, which uses minimum hop-count as the metric for route selection, facing intermittent connectivity frequently which would cause QoS of network degradation in Ad Hoc Network. In this paper, we integrate three cross layer infor-mation which consists of the remaining energy of nodes, the remaining queue length and the hop-count from source node to destination node. Then we present the GRA-AODV routing protocol based on the gray relevance algorithm. By comparing the simulation and experimental results, in the case of slightly increase in routing overhead, the improved Gray Relevance Algorithm-AODV routing possesses lower average end to end delay and lower packet loss rate, and it has superior robustness in the mobile Ad Hoc Network with network topology changing frequently

In situ isotopic studies of the U-depleted Allende CAI Curious Marie: Pre-accretionary alteration and the co-existence of ^(26)Al and ^(36)Cl in the early solar nebula

The isotopic composition of oxygen as well as ^(26)Al-^(26)Mg and ^(36)Cl-^(36)S systematics were studied in Curious Marie, an aqueously altered Allende CAI characterized by a Group II REEpattern and a large ^(235)U excess produced by the decay of short-lived ^(247)Cm. Oxygen isotopic compositions in the secondary minerals of Curious Marie follow a mass-dependent fractionation line with a relatively homogenous depletion in ^(16)O (Δ^(17)O of −8‰) compared to unaltered minerals of CAI components. Both Mg and S show large excesses of radiogenic isotopes (^(26)Mg∗ and ^(36)S∗) that are uniformly distributed within the CAI, independent of parent/daughter ratio. A model initial ^(26)Al/^(27)Al ratio [(6.2 ± 0.9) × 10^(−5)], calculated using the bulk Al/Mg ratio and the uniform δ^(26)Mg∗ ∼ +43‰, is similar to the canonical initial solar system value within error. The exceptionally high bulk Al/Mg ratio of this CAI (∼95) compared to other inclusions is presumably due to Mg mobilization by fluids. Therefore, the model initial ^(26)Al/^(27)Al ratio of this CAI implies not only the early condensation of the CAI precursor but also that aqueous alteration occurred early, when ^(26)Al was still at or near the canonical value. This alteration event is most likely responsible for the U depletion in Curious Marie and occurred at most 50 kyr after CAI formation, leading to a revised estimate of the early solar system ^(247)Cm/^(235)U ratio of (5.6 ± 0.3) × 10^(−5). The Mg isotopic composition in Curious Marie was subsequently homogenized by closed-system thermal processing without contamination by chondritic Mg. The large, homogeneous ^(36)S excesses (Δ^(36)S∗ ∼ +97‰) detected in the secondary phases of Curious Marie are attributed to ^(36)Cl decay (t_(1/2) = 0.3 Myr) that was introduced by Cl-rich fluids during the aqueous alteration event that led to sodalite formation. A model ^(36)Cl/^(35)Cl ratio of (2.3 ± 0.6) × 10^(−5) is calculated at the time of aqueous alteration, translating into an initial ^(36)Cl/^(35)Cl ratio of ∼1.7–3 × 10^(−5) at solar system birth. The Mg and S radiogenic excesses suggest that ^(26)Al and ^(36)Cl co-existed in the early solar nebula, raising the possibility that, in addition to an irradiation origin, ^(36)Cl could have also been derived from a stellar source

In situ isotopic studies of the U-depleted Allende CAI Curious Marie: Pre-accretionary alteration and the co-existence of ^(26)Al and ^(36)Cl in the early solar nebula

The isotopic composition of oxygen as well as ^(26)Al-^(26)Mg and ^(36)Cl-^(36)S systematics were studied in Curious Marie, an aqueously altered Allende CAI characterized by a Group II REEpattern and a large ^(235)U excess produced by the decay of short-lived ^(247)Cm. Oxygen isotopic compositions in the secondary minerals of Curious Marie follow a mass-dependent fractionation line with a relatively homogenous depletion in ^(16)O (Δ^(17)O of −8‰) compared to unaltered minerals of CAI components. Both Mg and S show large excesses of radiogenic isotopes (^(26)Mg∗ and ^(36)S∗) that are uniformly distributed within the CAI, independent of parent/daughter ratio. A model initial ^(26)Al/^(27)Al ratio [(6.2 ± 0.9) × 10^(−5)], calculated using the bulk Al/Mg ratio and the uniform δ^(26)Mg∗ ∼ +43‰, is similar to the canonical initial solar system value within error. The exceptionally high bulk Al/Mg ratio of this CAI (∼95) compared to other inclusions is presumably due to Mg mobilization by fluids. Therefore, the model initial ^(26)Al/^(27)Al ratio of this CAI implies not only the early condensation of the CAI precursor but also that aqueous alteration occurred early, when ^(26)Al was still at or near the canonical value. This alteration event is most likely responsible for the U depletion in Curious Marie and occurred at most 50 kyr after CAI formation, leading to a revised estimate of the early solar system ^(247)Cm/^(235)U ratio of (5.6 ± 0.3) × 10^(−5). The Mg isotopic composition in Curious Marie was subsequently homogenized by closed-system thermal processing without contamination by chondritic Mg. The large, homogeneous ^(36)S excesses (Δ^(36)S∗ ∼ +97‰) detected in the secondary phases of Curious Marie are attributed to ^(36)Cl decay (t_(1/2) = 0.3 Myr) that was introduced by Cl-rich fluids during the aqueous alteration event that led to sodalite formation. A model ^(36)Cl/^(35)Cl ratio of (2.3 ± 0.6) × 10^(−5) is calculated at the time of aqueous alteration, translating into an initial ^(36)Cl/^(35)Cl ratio of ∼1.7–3 × 10^(−5) at solar system birth. The Mg and S radiogenic excesses suggest that ^(26)Al and ^(36)Cl co-existed in the early solar nebula, raising the possibility that, in addition to an irradiation origin, ^(36)Cl could have also been derived from a stellar source