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Understanding siderophile element partitioning between metal and silicate melts under diverse conditions can be used to place important constraints on the materials and conditions of planetary accretion and core formation, as well as post core formation processes. However, the effects of Si on the partitioning and activity coefficients for these elements are not well known, despite Si likely being one of the dominant light elements in Earth's core. To address this gap in understanding, we have undertaken a systematic study of the highly siderophile elements Re, Pt, Os, and Ru, and the refractory lithophile elements Nb, Ta and Ti at 1600 °C and 1 GPa, to derive epsilon interaction parameters for these elements in FeSi metallic liquids. Positive epsilon interaction parameters were measured for Nb, Ta, Ti, Ru, Re, Pt, and Os, indicating that dissolved Si in Fe liquids causes a decrease in their metal/silicate partition coefficients (or 'silicophobic' behavior). Furthermore, ε Re , O s , o r R u Si > ε Re , O s , o r R u S which means Si causes a larger decrease in D(metal/silicate) than S, and the chalcophile behavior expected from some elements will be completely masked by the presence of Si in a metallic liquid. The new parameters are used to update an activity model that now includes 36 siderophile elements in Fe-Ni-Si-S-C liquids (27 trace elements considered here). Systematic assessment of these 27 elements shows which have the strongest affinity for Si, C, and S, and also how activity coefficients for these elements would vary during accretion and core formation in Earth, Mars, and Mercury of widely differing fO 2 and core compositional conditions. The activity model is combined with new partitioning expressions for Mo, W, Cr, Re Ru, Pt, and Os and applied to aspects of post core formation mantle geochemistry of Earth, Mars, and Mercury. Our updated expressions show that the BSE Mo/W ratio can easily be achieved with metal/silicate partitioning during growth of the Earth, whereas Re, Os and Ru become lower than and highly fractionated compared with BSE values during core formation and accretion, and thus nearly 99% of their BSE abundances are likely contributed by late accretion. Ru isotopes should be a very good indicator of the source material for the late accretion. The high Pt/Os and Re/Os developed in a deepening magma ocean during the growth of the Earth, indicates 186Os and 187Os isotopes could be coupled if this ancient material remained isolated and subsequently became entrained in mantle plumes and measured in surficial lavas. The extent to which this occurred will be limited by the low Os content of this ancient material, thus requiring mixing as a major component in plume sources. Martian mantle Hf/W ratio stays low during accretion and core formation modelling, suggesting that W isotope anomalies are more likely due to solid/liquid silicate fractionation than to core formation. Finally, Ti contents measured by MESSENGER at Mercury's surface can be explained by segregation of either a metallic core (IW-6 to -8) or metallic core + sulfide (IW-4 to -7.5) followed by mantle melting. [ABSTRACT FROM AUTHOR]

Adequate postoperative morphine consumption and pain management after thoracic surgery are major issues in the prevention of respiratory complications. Opioid-free anesthesia (OFA) may decrease morphine consumption and postoperative pain. The objective of this study was to evaluate the impact of OFA on the consumption of morphine and pain after video-assisted thoracic surgery or robotic-assisted thoracic surgery. The main objective of this retrospective study with propensity score analysis (PSA) was to compare the cumulative postoperative morphine consumption at 48 hours between an OFA group receiving dexmedetomidine, lidocaine, and ketamine; and an opioid anesthesia (OA) group receiving remifentanil plus morphine. Postoperative pain at 24 and 48 hours and respiratory and hemodynamics complications were also assessed. Eighty-one patients were included, 48 in the OFA group and 33 in the OA group. The cumulative postoperative morphine consumption at 48 hours was lower in the OFA group than in the OA group (28.5 mg [0 to 62.25 mg] vs 55 mg [34 to 79.5 mg], P =.002, with PSA; OFA −27.67 mg [−46 mg to −11.5 mg], P =.002). The postoperative pain score was significantly lower in the OFA group compared with the OA group at 24 hours (2 [0 to 4] vs 3 [2 to 5], P =.064, with PSA; OFA −1.40 [−2.47 to −0.33], P =.0088) and 48 hours (0 [0 to 3] vs 2.5 [0 to 5], P =.034, with PSA; OFA −1.87 [−3.45 to −0.28], P =.021). There were no differences between groups concerning respiratory or hemodynamic complications. Our results suggest that OFA after video-assisted thoracic surgery or robotic-assisted thoracic surgery is safe and is associated with less postoperative morphine cumulative consumption and pain at 48 hours. [Display omitted] [ABSTRACT FROM AUTHOR]

Alkali metals Na, K, Rb and Cs are depleted in planetary mantles and their depletion is commonly attributed to the effect of volatility during the condensation of the first solids in the solar nebula or the high temperatures involved during planetary growth. Most models of planetary differentiation assume that alkalis behave entirely as lithophile elements and do not participate in core segregation. Here, we tested this hypothesis by determining experimentally the partitioning of Na, Cs and Rb between iron sulfide and silicate (D sulf/sil) and combining it with available data from the literature on K, Na and Cs partitioning. Our experiments were conducted at 1–3.5 GPa, with an additional one at 8 GPa, 1600–1900 °C, and varying FeO contents, which lead to a relatively large range of O content in the sulfide phases (up to 13 wt%). We found maximum D sulf/sil of 0.8, 0.4, and 0.36 for Na, Cs and Rb respectively. In addition, D sulf/sil for Na, K, Cs and Rb increases with temperature and O content in the sulfide and decreases with FeO content in the silicate. The degree of polymerization of the silicate melt and the S content of the sulfide additionally increase D sulf/sil for Na, K and Cs. Since the solubility of O in sulfides is correlated with the FeO content of the silicate and both have opposite effects on D sulf/sil , varying the oxidation state of equilibrating material does not significantly affect D sulf/sil , which is more controlled by the temperature of equilibration. We modeled core formation for Earth, Mars and asteroid Vesta, assuming that some of the accreted embryos contained immiscible sulfides, that segregated into planetary cores. Our results show that with such a scenario, significant amounts of Na, K, Cs and Rb were sequestered in planetary cores, leading to core/mantle distribution of alkalis between 4·10−5 and 0.15. The depletion of alkalis in the mantles of Earth, Mars and Vesta could have resulted from combined effects of volatility and core segregation, but are largely due to volatile depletion in the accreting materials. [ABSTRACT FROM AUTHOR]

The present work investigates the CO 2 capture by activated carbons prepared from Argan fruits shells. The protocol consist on carbonization followed by activation using wet impregnation or dry physical mixing with activating agents such as KOH or NaOH. The as-prepared samples have been subjected to textural investigations and comprehensive characterizations using scanning electron microscopy, energy dispersive X-ray diffraction, Raman and FTIR spectroscopy. Values of specific surface areas and pore volume up to 2251 m 2 /g and 1.04 cm 3 /g, respectively, were extracted from adsorption isotherms that allow, also, determination of pores sizes and surface energy distributions. Of interest, the chemical composition given by EDX revealing significant N content up to 13.90 wt% and approved by FTIR spectroscopy. Moreover, the CO 2 isotherms measured, under 1 bar and 25 °C, show uptake capacity reaching 5.63 mmol/g. This values is likely attributed to CO 2 adsorption by the prepared activated carbon combining large surface area, narrow micropores and the N containing surface functionalities. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing (CPET) for patients awaiting lung resection for non–small cell lung cancer (NSCLC) has developed considerably in recent years. Pulmonary rehabilitation before surgery (prehabilitation) improves postoperative risk factors such as forced expiratory volume in 1 second and peak oxygen consumption (VO 2peak). Ventilatory inefficiency assessed according to the linear regression of the ratio between the increase in minute ventilation and the expired carbon dioxide flow during CPET (VE/VCO 2 slope) >35, is a high-risk factor for postoperative complications. Our objective was to assess the effect of prehabilitation on VE/VCO2 slope, and its relationship with VO 2peak. This retrospective cohort study was performed between January 1, 2014 and December 31, 2017 at Rouen University Hospital. One hundred fifty-two patients with NSCLC awaiting lung surgery who underwent CPET were screened. A total of 50 patients who underwent CPET before and after prehabilitation were included. VE/VCO 2 slope did not change significantly after prehabilitation (median, 37.1 [25th-75th percentile, 33.8-43.4] vs median, 35.4 [25th-75th percentile, 31.1-40.5]; P =.09), whereas VO 2peak increased significantly (from a median of 13.2 [25th-75th percentile, 11.9-14.7] to a median of 14.8 [25th-75th percentile, 13.1-16.4] mL/kg/min). The number of patients with a high risk of postoperative complications (ie, VE/VCO 2 slope >35) did not change significantly after prehabilitation. Cardiorespiratory parameters improved significantly more in patients who underwent at least 15 sessions of ambulatory prehabilitation. VE/VCO 2 slope, a known predictor of favorable surgical outcomes in patients with NSCLC, did not change with the prehabilitation program used in this study, despite clear improvements in VO 2peak and other CPET measures. Larger, prospective studies are needed to confirm the results of this study. [ABSTRACT FROM AUTHOR]

Earth’s core contains ∼10% of a light element that may be a combination of Si, S, C, O or H, with Si potentially being the major light element. Metal-silicate partitioning of siderophile elements can place important constraints on the P-T-fO 2 and composition of the early Earth, but the effect of Si alloyed in Fe liquids is unknown for many of these elements. In particular, the effect of Si on the partitioning of highly siderophile elements (Au, Re and PGE) is virtually unknown. To address this gap in understanding, we have undertaken a systematic study of the highly siderophile elements Au, Pd, and Pt, and the volatile siderophile elements P, Ga, Cu, Zn, and Pb at variable Si content of metal, and 1600 °C and 1 GPa. From our experiments we derive epsilon interaction parameters between these elements and Si in Fe metallic liquids. The new parameters are used to update an activity model for trace siderophile elements in Fe alloys; Si causes large variation in the magnitude of activity coefficients of these elements in FeSi liquids. Because the interaction parameters are all positive, Si causes a decrease in their metal/silicate partition coefficients. We combine these new activity results with experimental studies of Au, Pd, Pt, P, Ga, Cu, Zn and Pb, to derive predictive expressions for metal/silicate partition coefficients which can then be applied to Earth. The expressions are applied to two scenarios for continuous accretion of Earth; specifically for constant and increasing fO 2 during accretion. The results indicate that mantle concentrations of P, Ga, Cu, Zn, and Pb can be explained by metal-silicate equilibrium during accretion of the Earth where Earth’s early magma ocean deepens to pressures of 40–60 GPa. Au, Pd, and Pt, on the other hand become too high in the mantle in such a scenario, and require a later removal mechanism, rather than an addition as traditionally argued. A late reduction event that removes 0.5% metal from a shallow magma ocean can lower the Au, Pd, and Pt contents to values near the current day BSE. On the other hand, removal of 0.2–1.0% of a late sulfide-rich matte to the core would lower the Au, Pd, and Pt concentrations in the mantle, but not to chondritic relative concentrations observed in the BSE. If sulfide matte is called upon to remove HSEs, they must be later added via a late veneer to re-establish the high and chondritic relative PUM concentrations. These results suggest that although accretion and core formation (involving a Si, S, and C-bearing metallic liquid) were the primary processes establishing many of Earth’s mantle volatile elements and HSE, a secondary removal process is required to establish HSEs at their current and near-chondritic relative BSE levels. Mn and P - two siderophile elements that are central to biochemical processes (photosynthesis and triphosphates, respectively) - have significant and opposite interactions with FeSi liquids, and their mantle concentrations would be notably different if Earth had a Si-free core. [ABSTRACT FROM AUTHOR]

Knowledge of melting properties is critical to predict the nature and the fate of melts produced in the deep mantle. Early in the Earth’s history, melting properties controlled the magma ocean crystallization, which potentially induced chemical segregation in distinct reservoirs. Today, partial melting most probably occurs in the lowermost mantle as well as at mid upper-mantle depths, which control important aspects of mantle dynamics, including some types of volcanism. Unfortunately, despite major experimental and theoretical efforts, major controversies remain about several aspects of mantle melting. For example, the liquidus of the mantle was reported (for peridotitic or chondritic-type composition) with a temperature difference of ∼1000 K at high mantle depths. Also, the Fe partitioning coefficient (D Fe Bg/melt ) between bridgmanite (Bg, the major lower mantle mineral) and a melt was reported between ∼0.1 and ∼0.5, for a mantle depth of ∼2000 km. Until now, these uncertainties had prevented the construction of a coherent picture of the melting behavior of the deep mantle. In this article, we perform a critical review of previous works and develop a coherent, semi-quantitative, model. We first address the melting curve of Bg with the help of original experimental measurements, which yields a constraint on the volume change upon melting (ΔV m ). Secondly, we apply a basic thermodynamical approach to discuss the melting behavior of mineralogical assemblages made of fractions of Bg, CaSiO 3 -perovskite and (Mg,Fe)O-ferropericlase. Our analysis yields quantitative constraints on the SiO 2 -content in the pseudo-eutectic melt and the degree of partial melting (F) as a function of pressure, temperature and mantle composition; For examples, we find that F could be more than 40% at the solidus temperature, except if the presence of volatile elements induces incipient melting. We then discuss the melt buoyancy in a partial molten lower mantle as a function of pressure, F and D Fe Bg/melt . In the lower mantle, density inversions (i.e. sinking melts) appear to be restricted to low F values and highest mantle pressures. The coherent melting model has direct geophysical implications: (i) in the early Earth, the magma ocean crystallization could not occur for a core temperature higher than ∼5400 K at the core-mantle boundary (CMB). This temperature corresponds to the melting of pure Bg at 135 GPa. For a mantle composition more realistic than pure Bg, the right CMB temperature for magma ocean crystallization could have been as low as ∼4400 K. (ii) There are converging arguments for the formation of a relatively homogeneous mantle after magma ocean crystallization. In particular, we predict the bulk crystallization of a relatively large mantle fraction, when the temperature becomes lower than the pseudo-eutectic temperature. Some chemical segregation could still be possible as a result of some Bg segregation in the lowermost mantle during the first stage of the magma ocean crystallization, and due to a much later descent of very low F, Fe-enriched, melts toward the CMB. (iii) The descent of such melts could still take place today. There formation should to be related to incipient mantle melting due to the presence of volatile elements. Even though, these melts can only be denser than the mantle (at high mantle depths) if the controversial value of D Fe Bg/melt is indeed as low as suggested by some experimental studies. This type of melts could contribute to produce ultra-low seismic velocity anomalies in the lowermost mantle. [ABSTRACT FROM AUTHOR]

A large number of siderophile (iron-loving) elements are also volatile, thus offering constraints on the origin of volatile elements in differentiated bodies such as Earth, Moon, Mars and Vesta. Metal–silicate partitioning data for many of these elements is lacking, making their overall mantle concentrations in these bodies difficult to model and origin difficult to distinguish between core formation and volatile depletion. To address this gap in understanding, we have undertaken systematic studies of four volatile siderophile elements – Sb, As, Ge and In – at variable temperature and variable Si content of metal. Several series were carried out at 1 GPa, and between 1500 and 1900 °C, for both C saturated and C-free conditions. The results show that temperature causes a decrease in the metal/silicate partition coefficient for all four elements. In addition, activity coefficients for each element have been determined and show a very strong dependence on Si content of Fe alloy. Si dissolved in metal significantly decreases the metal/silicate partition coefficients, at both 1600 and 1800 °C. The combination of temperature and Si content of the metal causes reduction of the metal–silicate partition coefficient to values that are close to those required for an origin of mantle As, Sb, Ge, and In concentrations by metal–silicate equilibrium processes. Combining these new results with previous studies on As, Sb, Ge, and In, allowed derivation of predictive expressions for metal/silicate partition coefficients for these elements which can then be applied to Earth. The expressions are applied to two scenarios for continuous accretion of Earth; specifically for constant and increasing fO 2 during accretion. The results indicate that mantle concentrations of As, Sb, Ge, and In can be explained by metal–silicate equilibrium during an accretion scenario. The modeling is not especially sensitive to either scenario, although all element concentrations are explained better by a model with variable fO 2 . The specific effect of Si is important and calculations that include only S and C (and no Si) cannot reproduce the mantle As, Sb, Ge, and In concentrations. The final core composition in the variable fO 2 model is 10.2% Si, 2% S, and 1.1% C (or X Si = 0.18, X S = 0.03, and X C = 0.04. These results suggest that core formation (involving a Si, S, and C-bearing metallic liquid) and accretion were the most important processes establishing many of Earth’s mantle volatile elements (indigenous), while post-core formation addition or re-equilibration (exogenous) was of secondary or minor importance. [ABSTRACT FROM AUTHOR]