Density deficit of Earth’s core revealed by a multimegabar primary pressure scale

An accurate pressure scale is a fundamental requirement to understand planetary interiors. Here, we establish a primary pressure scale extending to the multimegabar pressures of Earth’s core, by combined measurement of the acoustic velocities and the density from a rhenium sample in a diamond anvil cell using inelastic x-ray scattering and x-ray diffraction. Our scale agrees well with previous primary scales and shock Hugoniots in each experimental pressure range and reveals that previous scales have overestimated laboratory pressures by at least 20% at 230 gigapascals. It suggests that the light element content in Earth’s inner core (the density deficit relative to iron) is likely to be double what was previously estimated, or Earth’s inner core temperature is much higher than expected, or some combination thereof

Carbazole and indolcarbazole-based systems: impact of the structural changes on the system properties

π-Conjugated diradical compounds, featuring unique unsaturated valences and radical centres in the ground state, are fundamentally important for understanding the nature of chemical bonds and have potential applications in material science [1] . During the last decade, there has been an increasing interest in the rationalization of how the structural changes stabilize (or destabilize) the diradical system. The tunability of the diradical character has been studied for different structural motifs such as the substitution pattern of lateral groups[2], the elongation of the conjugated core[3] or the molecular isomerism[4], among others. In this sense, we have recently reported an experimental/theoretical study of a family of carbazole-based diradicaloids with dicyanomethylene (DCM) groups incorporated via para (p-Cz and p-ICz) or meta positions (mCz and m-ICz) aiming to investigate how external stimuli impact on the molecular structure and supramolecular organization, and thus on the resulting optical and electronic properties. In addition, we theoretically investigate at the DFT level a set of ten indolocarbazole-based isomers substituted with DCM groups to disclose how their chemical reactivity and physical properties are affected by isomerism and different substitution pattern.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Plan Propio de Investigación de la UM

Formation of Cyclophane Macrocycles in Carbazole-Based Biradicaloids: Impact of the Dicyanomethylene Substitution Position

We have recently demonstrated that carbazole-based biradicaloids are promising building blocks in dynamic covalent chemistry. To elucidate their intriguing dynamic covalent chemical properties, it is necessary to understand the physical origin of their biradical nature. To this end, here we focus on two quinoid carbazole systems substituted with dicyanomethylene (DCM) groups via para (p-Cz-alkyl) or meta positions (m-Cz-ph), which are able to form cyclophane macrocycles by the formation of long C–C bonds between the bridgehead carbon atoms linked to the DCM groups. We aim at exploring the following questions: (i) How is the biradicaloid character of a quinoid carbazole affected by the substitution position of the DCM groups? (ii) How is the stability of the resulted cyclophane aggregate attained? (iii) How is the dynamic interconversion between the carbazole-based monomers and cyclophane aggregates affected by this subtle change in the substitution pattern position? Density functional theory-based calculations reveal that both p-Cz-alkyl and m-Cz-ph are open-shell biradicals in the ground electronic state, with the DCM substitution in the meta position resulting in a more pronounced biradical character. In contrast, the derivatization via the nitrogen of the carbazole unit is not predicted to affect the biradicaloid character. The spontaneous nature of the cyclophane-based macrocycle formation (i.e., the cyclic tetramer in p-Cz-alkyl and the cyclic trimer and the tetramer in m-Cz-ph) is supported by the negative relative Gibbs free energies calculated at 298 K. Interestingly, cyclic oligomers in which the DCM groups are inserted in the meta position tend to adopt folded conformations with attractive π–π interactions resulting in more stable aggregates; in contrast, note that an extended ring-shaped conformation is acquired for (p-Cz-alkyl)4. In addition, the larger spin density on the bridgehead carbon atom in the meta-substituted system strengthens the bridging C–C bond in the aggregate forms, hampering its dissociation. In fact, the C–C bond dissociation of (m-Cz-ph)4 and (m-Cz-ph)3 was suppressed in solution state, although it was achieved in solid state in response to soft external stimuli (i.e., temperature and grinding). In summary, we report a very comprehensive study aiming at elucidating the challenging chemical properties of carbazole-based biradicaloid systems.The work at the University of Málaga was funded by the MINECO (CTQ2015-66897) and Junta de Andalucía (P09-FQM-4708) projects. The work at the University of Alicante was supported by the MINECO (CTQ2014-55073) and Generalitat Valenciana (AICO/2018/175) projects

Analysis of gut microbiome, host genetics, and plasma metabolites reveals gut microbiome-host interactions in the Japanese population

Interaction between the gut microbiome and host plays a key role in human health. Here, we perform a metagenome shotgun-sequencing-based analysis of Japanese participants to reveal associations between the gut microbiome, host genetics, and plasma metabolome. A genome-wide association study (GWAS) for microbial species (n = 524) identifies associations between the PDE1C gene locus and Bacteroides intestinalis and between TGIF2 and TGIF2-RAB5IF gene loci and Bacteroides acidifiaciens. In a microbial gene ortholog GWAS, agaE and agaS, which are related to the metabolism of carbohydrates forming the blood group A antigen, are associated with blood group A in a manner depending on the secretor status determined by the East Asian-specific FUT2 variant. A microbiome-metabolome association analysis (n = 261) identifies associations between bile acids and microbial features such as bile acid metabolism gene orthologs including bai and 7β-hydroxysteroid dehydrogenase. Our publicly available data will be a useful resource for understanding gut microbiome-host interactions in an underrepresented population.Tomofuji Yoshihiko, Kishikawa Toshihiro, Sonehara Kyuto, et al. Analysis of gut microbiome, host genetics, and plasma metabolites reveals gut microbiome-host interactions in the Japanese population. Cell Reports 42, 113324 (2023); https://doi.org/10.1016/j.celrep.2023.113324

Molecular analysis of the BCR-ABL1 kinase domain in chronic-phase chronic myelogenous leukemia treated with tyrosine kinase inhibitors in practice: Study by the Nagasaki CML Study Group

An appropriate trigger for BCR-ABL1 mutation analysis has not yet been established in unselected cohorts of chronic-phase chronic myelogenous leukemia patients. We examined 92 patients after 12 months of tyrosine kinase inhibitor (TKI) treatment in Nagasaki Prefecture, Japan. Univariate analysis revealed that significant factors associated with not attaining a major molecular response (MMR) were the presence of the minor BCR-ABL1 fusion gene, a low daily dose of TKI, and the emergence of BCR-ABL1 kinase domain mutations conferring resistance to imatinib. Factors associated with the loss of sustained MMR were a low daily dose of TKI and the emergence of alternatively spliced BCR-ABL1 mRNA with a 35-nucleotide insertion. Taken together, our results suggest that the search for BCR-ABL1 mutations should be initiated if patients have not achieved MMR following 12 months of TKI treatment

Evaluation of Tomographic Technique of Temporomandibular Joint using COMMCAT IS-2000^<TM> Imaging System

COMMCAT IS-2000^は顎顔面領域専用の断層エックス線撮影装置で,顎関節の矢状断および冠状断撮影の機能を有する。本装置の顎関節撮影における有用性をエックス線不透過性の鋼鉄製マーカーを付けた4個のヒト乾燥頭蓋骨を用いて検討した。スライス位置の正確性を調べるため下顎頭の表面中央にマーカーを固定し,マーカー直上,それより近心,遠心にそれぞれ1mm,2mm離れた計5点に対して矢状断撮影を行ったところ,スライス位置の誤差は±1mmの範囲内であった。写真の寸法精度を調べるため,下顎頭の実測値と断層写真上での寸法をデジタルキャリパーを用いて比較した。両者の差は前後径では平均0.43mm,近遠心径では平均0.52mmであった。断層軌道および断層厚さの違いが写真画質におよぼす影響を調べた。同一撮影条件下ではhypocycloidal軌道で1mmの断層厚さで撮影した場合,ぶれや周囲の構造物の写り込みが少ないため,最も写真画質が良好であることがわかった。以上の結果よりCOMMCAT IS-2000^はTMJの骨構造を画像化する上で有用な診断装置であることが示唆された。The COMMCAT IS-2000^ (Imaging Sciences International, Hatfield, PA, USA) is a tomographic machine for scanning the dentomaxillofacial region and is capable of imaging the sagittal and coronal sections of the temporomandibular joint (TMJ). The feasibility and accuracy of tomography for the TMJ were examined by use of the COMMCAT IS-2000^ and four dried human skulls with radiopaque steel markers. To assess the setting accuracy of the slice position, a steel marker was fixed at the center of the superior surface of the condyle, and images of five sagittal sections were taken, i.e., directly above the marker and 1 mm and 2 mm distance from it in both the medial and distal planes. The deviation of the slice position was found to be within ± 1 mm for all test subjects. To evaluate the dimensional accuracy of this method, the difference between the actual value and the graphically observed value with respect to the tomographic image of the condyle was examined using a digital caliper. The difference between values for the anteroposterior distance was 0.43 mm and that for the mediolateral distance was 0.52 mm. The effect of the difference in tomographic motion and slice thickness on the image quality was then evaluated. Under identical exposure conditions, hypocycloidal tube motion and the slice thickness of 1 mm produced the best image quality because blurring of the image and the degree of superimposition of the surrounding structures were minimal. These results suggest that the COMMCAT IS-2000^ is a high-quality diagnostic tool for visualizing the bone structure of the TMJ

特異な構造を有する芳香族アミン分子の電子的性質に関する研究

京都大学0048新制・課程博士博士(工学)甲第17524号工博第3683号新制||工||1560(附属図書館)30290京都大学大学院工学研究科分子工学専攻(主査)教授 田中 一義, 教授 横尾 俊信, 教授 佐藤 啓文学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

High-spin polycationic states of an alternate meta-para-linked oligoarylamine incorporating two macrocycles.

High-spin alignment for dicationic, tricationic, tetracationic and hexacationic species of a meta-para-linked oligoarylamine was accomplished by incorporating cyclophane skeletons into the oligomer backbone

Nitrogen-embedded buckybowl and its assembly with C[60]

Curved π-conjugated molecules have attracted considerable interest because of the unique properties originating from their curved π surface. However, the synthesis of such distorted molecules requires harsh conditions, which hamper easy access to heteroatom-containing curved π systems. Here we report the synthesis of a π-extended azacorannulene with nitrogen in its centre. The oxidation of 9-aminophenanthrene provides tetrabenzocarbazole, which is converted to the azabuckybowl through palladium-catalysed intramolecular coupling. The electron-donating nature and curved π surface of the azabuckybowl enable its tight association with C[60] in solution and solid states. High charge mobility is observed for the azabuckybowl/C[60] assembly. This compound may be of interest in the fields of curved π systems as fullerene hosts, anisotropic π donors and precursors to nitrogen-containing nanocarbon materials

Intramolecular electron transfer in multi-redox systems based on cyclic [3]spirobifluorenylene compound

Cyclic [3]spirobifluorenylene with bulky alkyl groups at the ends (1) was designed and synthesized to investigate the electron transfer phenomena in a -conjugated system including orthogonal -conjugated chains. The three bifluorenyl units in 1 are conjugated to each other via spiro-conjugation, resulting in the splitting of the HOMO levels to a small extent. Therefore, the SOMO–HOMO gap of the radical cation species is small, which is considered to allow the facile intramolecular electron transfer. The electronic properties of 1 and its partial structures were characterized by absorption and fluorescence measurements and electrochemical analysis. From the electrochemical oxidation, the interchain Coulombic repulsion was observed. In the TD-DFT calculations for the radical cation species of 1, the geometry-featured interchain electronic transitions were visualized by NTO calculations. The radical cation species of 1 generated by chemical oxidation with SbCl5 exhibited a broadened and lower-energy shifted NIR absorption band compared to those of its partial structures. Considering the results of the TD-DFT calculations, the NIR band of the radical cation of 1 was attributed to the intramolecular electron transfer processes among the bifluorenyl units in the macrocycle. ESR experiments also indicated the delocalization of a spin of 1·+ in the whole molecule via hole hopping. This work demonstrates the usefulness of spiro-conjugation as a bridging unit in molecular wires to facilitate smooth electron transfer