Pressure Destabilizes Oxygen Vacancies in Bridgmanite

Bridgmanite may contain a large proportion of ferric iron in its crystal structure in the forms of FeFeO3 and MgFeO2.5 components. We investigated the pressure dependence of FeFeO3 and MgFeO2.5 contents in bridgmanite coexisting with MgFe2O4-phase and with or without ferropericlase in the MgO-SiO2-Fe2O3 ternary system at 2,300 K, 33 and 40 GPa. Together with the experiments at 27 GPa reported in Fei et al. (2020, https://doi.org/10.1029/2019GL086296), our results show that the FeFeO3 and MgFeO2.5 contents in bridgmanite decrease from 7.6 to 5.3 mol % and from 2 to 3 mol % to nearly zero, respectively, with increasing pressure from 27 to 40 GPa. Accordingly, the total Fe3+ decreases from 0.18 to 0.11 pfu. The formation of oxygen vacancies (MgFeO2.5 component) in bridgmanite is therefore dramatically suppressed by pressure. Oxygen vacancies can be produced by ferric iron in Fe3+-rich bridgmanite under the topmost lower mantle conditions, but the concentration should decrease rapidly with increasing pressure. The variation of oxygen-vacancy content with depth may potentially affect the physical properties of bridgmanite and thus affect mantle dynamics

Unexpected Semi-Metallic BiS2 at High Pressure and High Temperature

In the last decade, the group V-VI compounds have been widely investigated due to their excellent properties and applications. It is now accepted that diverse stoichiometry can yield new compounds with unanticipated properties, uncovering potentially new physicochemical mechanisms. However, in this group, aside from the conventional A2B3-type, no other energetically stable stoichiometry has been reported yet. Here, we report that Bi2S3 is unstable and decomposes into stoichiometric BiS2 and BiS with different Bi valence states are favored upon compression. Encouragingly, we successfully synthesized the predicted BiS2 phase and thus, confirmed its existence. Our current calculations reveal that the found BiS2 phase is a semi-metal, associated with the increased concentration of nonmetallic S. The present results represent the first counterintuitive stable stoichiometry of group V-VI and provide a good example in designing and synthesizing new compounds under compression

Common Variants in MAGI2 Gene Are Associated with Increased Risk for Cognitive Impairment in Schizophrenic Patients

Schizophrenia is a complex psychiatric disorder characterized by positive symptoms, negative symptoms, and cognitive impairment. MAGI2, a relatively large gene (∼1.5 Mbps) that maps to chromosome 7q21, is involved in recruitment of neurotransmitter receptors such as AMPA- and NMDA-type glutamate receptors. A genetic association study designed to evaluate the association between MAGI2 and cognitive performance or schizophrenia has not been conducted. In this case-control study, we examined the relationship of single nucleotide polymorphism (SNP) variations in MAGI2 and risk for schizophrenia in a large Japanese sample and explored the potential relationships between variations in MAGI2 and aspects of human cognitive function related to glutamate activity. Based on the result of first schizophrenia genome-wide association study in a Japanese population (JGWAS), we selected four independent SNPs and performed an association study using a large independent Japanese sample set (cases 1624, controls 1621). Wisconsin Card Sorting Test (WCST) was used to evaluate executive function in 114 cases and 91 controls. We found suggestive evidence for genetic association of common SNPs within MAGI2 locus and schizophrenia in Japanese population. Furthermore in terms of association between MAGI2 and cognitive performance, we observed that genotype effect of rs2190665 on WCST score was significant (p = 0.034) and rs4729938 trended toward significance (p = 0.08). In conclusion, although we could not detect strong genetic evidence for association of common variants in MAGI2 and increased schizophrenia risk in a Japanese population, these SNPs may increase risk of cognitive impairment in schizophrenic patients

Attenuated Food Anticipatory Activity and Abnormal Circadian Locomotor Rhythms in Rgs16 Knockdown Mice

Regulators of G protein signaling (RGS) are a multi-functional protein family, which functions in part as GTPase-activating proteins (GAPs) of G protein α-subunits to terminate G protein signaling. Previous studies have demonstrated that the Rgs16 transcripts exhibit robust circadian rhythms both in the suprachiasmatic nucleus (SCN), the master circadian light-entrainable oscillator (LEO) of the hypothalamus, and in the liver. To investigate the role of RGS16 in the circadian clock in vivo, we generated two independent transgenic mouse lines using lentiviral vectors expressing short hairpin RNA (shRNA) targeting the Rgs16 mRNA. The knockdown mice demonstrated significantly shorter free-running period of locomotor activity rhythms and reduced total activity as compared to the wild-type siblings. In addition, when feeding was restricted during the daytime, food-entrainable oscillator (FEO)-driven elevated food-anticipatory activity (FAA) observed prior to the scheduled feeding time was significantly attenuated in the knockdown mice. Whereas the restricted feeding phase-advanced the rhythmic expression of the Per2 clock gene in liver and thalamus in the wild-type animals, the above phase shift was not observed in the knockdown mice. This is the first in vivo demonstration that a common regulator of G protein signaling is involved in the two separate, but interactive circadian timing systems, LEO and FEO. The present study also suggests that liver and/or thalamus regulate the food-entrained circadian behavior through G protein-mediated signal transduction pathway(s)

A Survey on Parents’ Feelings and QOL of Children with Medical Complexity After Discharge from NICU under the COVID-19 Pandemic

【背景・目的】 　NICU を退院した後も医療的ケアを必要とする児が増加しており、A 病院では2018 年よりNICU 退院後も医療的ケアを要する児の両親の思いと生活の質に関する調査を継続している。また現在、COVID-19 感染拡大による面会制限の中、短時間で退院支援をしており、退院後の両親の状況、制限がある中での退院支援の課題を明確にする必要があると考えた。引き続き、NICU を退院した医療的ケアを要する児の両親の思いと生活の質を明確にすることを目的とし、本研究を実施した。 【方法】 　2021 年9 月から2022 年10 月にNICU を退院した医療的ケアを要する児の両親を対象に、質問紙調査を行なった。調査項目は、①基本属性、②退院後の両親の思い、③育児環境、④生活の質（WHO QOL26）とした。各項目の記述統計を算出後、父と母の群間比較にはχ2 検定、Mann-Whitney のU 検定を用いた。自由記載については類似内容ごとに分類しカテゴリーを抽出した。 【結果】 　19 人（8 組の両親と3 組の母）からアンケートを回収した（回収率67.9％）。WHO QOL26 平均値は父が3.36±0.52、母が3.35±0.59 であった。退院後の思いについては全員がポジティブな気持ちを抱いており、ネガティブな気持ちも抱いた者は78.9% であった。自由記載では、ポジティブな気持ちに、＜子どもといられる喜び＞などが挙げられ、ネガティブな気持ちに、＜自責の念＞＜入院時には想定していなかったケアや手技の難しさ＞などが挙げられた。面会制限による＜愛着形成への不安＞や＜配偶者との思い・育児手技の差異＞も記載されていた。 【考察・結論】 　本研究でのWHO QOL 得点の平均値は、2018 年からの先行研究と比較し、両親ともに低かった。また、全国平均値と比較し、母は身体的領域のQOL が低かった。面会制限のなか、父は面会できないことで役割遂行に戸惑いを感じ、母のみの退院支援となり、両親間に情報格差や育児ケア習得に差が生じたことで母への負担が大きくなったと考えられる。父の育児参加や父性育成促進のため、また、母の負担軽減のためにもタイムリーな面会制限の見直しと、各家族に応じた退院指導を行っていく必要がある。departmental bulletin pape

Density determination of liquid iron-nickel-sulfur at high pressure

International audienceThe density of liquid iron-nickel-sulfur (Fe 46.5 Ni 28.5 S 25) alloy was determined at pressures up to 74 GPa and an average temperature of 3400 K via pair distribution function (PDF) analysis of synchrotron X-ray diffraction (XRD) data obtained using laser-heated diamond anvil cells. The determined density of liquid Fe 46.5 Ni 28.5 S 25 at 74 GPa and 3400 K is 8.03(35) g/cm 3 , 15% lower than that of pure liquid Fe. The obtained density data were fitted to a third-order Vinet equation of state (EoS), and the determined isothermal bulk modulus and its pressure derivative at 24.6 GPa are K TPr = 110.5(250) GPa and K' TPr = 7.2 (25), respectively, with a fixed density of Pr = 6.43 g/cm 3 at 24.6 GPa. The change in the atomic volume of Fe 46.5 Ni 28.5 S 25 upon melting was found to be approximately 10% at the melting temperature, a significantly larger valu

An Experimental Examination of Thermal Conductivity Anisotropy in hcp Iron

The Earth's core mainly consists of iron, and its thermal transport properties are of vital importance for our understanding of the thermal evolution and the dynamics of the core and the mantle. However, the reported values of thermal conductivity of iron at the core conditions are so far inconclusive. Although hexagonal closed-packed (hcp) iron is often studied as a proxy metal to investigate the physical properties not only of the inner core, but also the outer core, the anisotropy of the thermal conductivity of hcp iron has never been experimentally examined. Here we report the results of texture analyses by means of synchrotron X-ray diffraction experiments and thermal conductivity measurements on polycrystalline hcp iron up to 44.5 GPa and 300 K. These results indicate that the thermal conductivity of single crystal hcp iron along c axis is about 3–4 times higher than that along a axis, which could have partially caused the controversial values of the thermal conductivity of hcp iron at the Earth's core conditions

Equation of State of Liquid Iron under Extreme Conditions

International audienceThe density of liquid iron has been determined up to 116 GPa and 4350 K via static compression experiments following an innovative analysis of diffuse scattering from liquid. The longitudinal sound velocity was also obtained to 45 GPa and 2700 K based on inelastic x-ray scattering measurements. Combining these results with previous shock-wave data, we determine a thermal equation of state for liquid iron. It indicates that the Earth’s outer core exhibits 7.5–7.6% density deficit, 3.7–4.4% velocity excess, and an almost identical adiabatic bulk modulus, with respect to liquid iron