Structural elucidation of a methylenation reagent of esters: synthesis and reactivity of a dinuclear titanium(iii) methylene complex

Transmetallation of a zinc methylene complex [ZnI(tmeda)](2)(mu-CH2) with a titanium(iii) chloride [TiCl3(tmeda)(thf)] produced a titanium methylene complex. The X-ray diffraction study displayed a dinuclear methylene structure [TiCl(tmeda)](2)(mu-CH2)(mu-Cl)(2). Treatment of an ester with the titanium methylene complex resulted in methylenation of the ester carbonyl to form a vinyl ether. The titanium methylene complex also reacted with a terminal olefin, resulting in olefin-metathesis and olefin-homologation. Cyclopropanation by methylene transfer from the titanium methylene proceeded by use of a 1,3-diene. The mechanistic study of the cyclopropanation reaction by the density functional theory calculations was also reported

Intravital imaging of orthotopic and ectopic bone

Bone homeostasis is dynamically regulated by a balance between bone resorption by osteoclasts and bone formation by osteoblasts. Visualizing and evaluating the dynamics of bone cells in vivo remain difficult using conventional technologies, including histomorphometry and imaging analysis. Over the past two decades, multiphoton microscopy, which can penetrate thick specimens, has been utilized in the field of biological imaging. Using this innovative technique, the in vivo dynamic motion of bone metabolism-related cells and their interactions has been revealed. In this review, we summarize previous approaches used for bone imaging and provide an overview of current bone tissue imaging methods using multiphoton excitation microscopy.Hashimoto K., Kaito T., Kikuta J., et al. Intravital imaging of orthotopic and ectopic bone. Inflammation and Regeneration 40, 26 (2020); https://doi.org/10.1186/s41232-020-00135-6

Coronagraphic Low Order Wave Front Sensor : post-processing sensitivity enhancer for high performance coronagraphs

Detection and characterization of exoplanets by direct imaging requires a coronagraph designed to deliver high contrast at small angular separation. To achieve this, an accurate control of low order aberrations, such as pointing and focus errors, is essential to optimize coronagraphic rejection and avoid the possible confusion between exoplanet light and coronagraphic leaks in the science image. Simulations and laboratory prototyping have shown that a Coronagraphic Low Order Wave-Front Sensor (CLOWFS), using a single defocused image of a reflective focal plane ring, can be used to control tip-tilt to an accuracy of 10^{-3} lambda/D. This paper demonstrates that the data acquired by CLOWFS can also be used in post-processing to calibrate residual coronagraphic leaks from the science image. Using both the CLOWFS camera and the science camera in the system, we quantify the accuracy of the method and its ability to successfully remove light due to low order errors from the science image. We also report the implementation and performance of the CLOWFS on the Subaru Coronagraphic Extreme AO (SCExAO) system and its expected on-sky performance. In the laboratory, with a level of disturbance similar to what is encountered in a post Adaptive Optics beam, CLOWFS post-processing has achieved speckle calibration to 1/300 of the raw speckle level. This is about 40 times better than could be done with an idealized PSF subtraction that does not rely on CLOWFS.Comment: 10 pages, 7 figures, accepted for publication in PAS

Chondrocyte-like cells in nucleus pulposus and articular chondrocytes have similar transcriptomic profiles and are paracrine-regulated by hedgehog from notochordal cells and subchondral bone

Objective: The nucleus pulposus (NP) comprises notochordal NP cells (NCs) and chondrocyte-like NP cells (CLCs). Although morphological similarities between CLCs and chondrocytes have been reported, interactions between CLCs and NCs remain unclear. In this study, we aimed to clarify regulatory mechanisms of cells in the NP and chondrocytes. Design: We performed single-cell RNA sequencing (scRNA-seq) analysis of the articular cartilage (AC) and NP of three-year-old cynomolgus monkeys in which NCs were present. We then performed immunohistochemical analysis of NP and distal femur. We added sonic hedgehog (SHH) to primary chondrocyte culture. Results: The scRNA-seq analysis revealed that CLCs and some articular chondrocytes had similar gene expression profiles, particularly related to GLI1, the nuclear mediator of the hedgehog pathway. In the NP, cell–cell interaction analysis revealed SHH expression in NCs, resulting in hedgehog signaling to CLCs. In contrast, no hedgehog ligands were expressed by chondrocytes in AC samples. Immunohistochemical analysis of the distal end of femur indicated that SHH and Indian hedgehog (IHH) were expressed around the subchondral bone that was excluded from our scRNA-seq sample. scRNA-seq data analysis and treatment of primary chondrocytes with SHH revealed that hedgehog proteins mediated an increase in hypoxia-inducible factor 1-alpha (HIF-1α) levels. Conclusion: CLCs and some articular chondrocytes have similar transcriptional profiles, regulated by paracrine hedgehog proteins secreted from NCs in the NP and from the subchondral bone in the AC to promote the HIF-1α pathway.Hagizawa H., Koyamatsu S., Okada S., et al. Chondrocyte-like cells in nucleus pulposus and articular chondrocytes have similar transcriptomic profiles and are paracrine-regulated by hedgehog from notochordal cells and subchondral bone. Frontiers in Cell and Developmental Biology 11, 1151947 (2023); https://doi.org/10.3389/fcell.2023.1151947

Antiferromagnetic structure of alkali metal superoxide CsO2_2

We have performed a powder neutron diffraction study on CsO$_2$, where the unpaired electron with $s=1/2$ in the $\pi^*$ orbital of the O$_2^-$ ion is responsible for the magnetism. The magnetic reflections 0 $\frac{1}{2}$ 0 and 0 $\frac{1}{2}$ 1 were observed below the N\'{e}el temperature of about 10 K. An antiferromagnetic structure with a propagation vector of (0 ,$\frac{1}{2}$, 0) and magnetic moments parallel to the $a$-axis is the most plausible. The magnitude of the ordered moment is about 0.2 $\mu_B$, which is considered to be strongly suppressed due to the one-dimensionality of the system. We propose a possible $\pi^*$ orbital order that can explain the obtained magnetic structure, and discuss its relation to the one-dimensionality

Carbon Monoxide Reduction Reaction to Produce Multicarbon Products in Acidic Electrolytes Using Gas Diffusion Electrode Loaded with Copper Nanoparticles

Kurihara R., Nagita K., Ohashi K., et al. Carbon Monoxide Reduction Reaction to Produce Multicarbon Products in Acidic Electrolytes Using Gas Diffusion Electrode Loaded with Copper Nanoparticles. Advanced Materials Interfaces , (2023); https://doi.org/10.1002/admi.202300731.The synthesis of multi-carbon products (C2+) by electrochemical CO2 reduction reaction (CO2RR) is a promising technology that will contribute to the realization of a carbon-neutral society. In particular, efficient CO2RR to produce C2+ in acidic electrolytes is desirable because the conversion of CO2 to inert (bi)carbonate can be suppressed under acidic conditions, thereby increasing the efficiency of substrate CO2 utilization. Herein, since C2+ products are produced via the dimerization of carbon monoxide, an intermediate in CO2RR, the focus is on the carbon monoxide reduction reaction (CORR). A gas diffusion electrode loaded with copper nanoparticles is used in acidic electrolytes to investigate the conditions necessary for efficient C2+ production. The faradaic efficiency and partial current density for C2+ production attained 75% and 280 mA cm−2 in a pH 2.0 solution, and they reached up to 66% and 260 mA cm−2 even in a pH 1.0 solution. Numerical simulations showed that increasing the alkalinity of the electrode surface to greater than pH 7 by consuming protons is necessary to facilitate the production of C2+ during the CORR. When the desired level of alkalinity is achieved, the concentration and type of alkali cations present at the electrode surface have an impact on the selectivity for C2+ production

Appropriate pelvic obliquity measurement method in Lenke type 5C adolescent idiopathic scoliosis: a preliminary study

Kanie Y., Takenaka S., Kitahara T., et al. Appropriate pelvic obliquity measurement method in Lenke type 5C adolescent idiopathic scoliosis: a preliminary study. Journal of Spine Surgery 10, 255 (2024); https://doi.org/10.21037/jss-23-138.Background: Although pelvic obliquity (PO) is a risk factor for postoperative coronal decompensation in corrective surgery in adolescent idiopathic scoliosis (AIS), especially Lenke 5C, methods of measuring PO are controversial. This study aimed to establish an appropriate measurement method using multiplanar reconstructed computed tomography (MPR-CT) images instead of standing posteroanterior (PA) whole-spine radiographs to evaluate PO in patients with Lenke 5C AIS. Methods: This study was a retrospective cross-sectional study. Twenty-five patients who underwent corrective surgery for AIS in Osaka University Hospital from August 2014 to February 2023 were included. Cobb angle, L5 tilt, C7 plumb line to center sacral vertebral line (C7PL-CSVL), and leg length discrepancy (LLD) were measured on standing PA whole-spine radiographs preoperatively. Sacral obliquity (SO), the slope of the upper endplate of S1, and iliac obliquity (IO), the tilt of the line connecting the iliac crests, were measured on standing PA whole-spine radiographs and MPR-CT (SO/IO-X-ray, SO/IO-CT, respectively). S1 angle and S2 angle were measured on CT. Results: The mean age of the patients was 18.7±3.9 years and all of them were females. SO-X-ray and SO-CT were larger than IO-X-ray and IO-CT, respectively. SO-X-ray was highly correlated with SO-CT (r=0.838, P<0.001). L5 tilt had higher correlation with SO-CT (r=0.884, P<0.001) than with SO-X-ray (r=0.726, P=0.001) and IO-CT (r=0.550, P=0.22). L5 tilt was correlated poorly with IO-X-ray (r=0.104, P=0.69). The S1 angle was 4.5±3.5° meanwhile the S2 angle was 1.2±2.1°, the sacral deformity was mainly due to the S1 vertebral wedging. Conclusions: Given the asymmetric sacral morphology, SO is more appropriate pelvic parameter than IO to represent the sacral tilt of Lenke 5C AIS, especially when measured using CT images to overcome the poor visibility on PA whole-spine radiographs

Anti-Siglec-15 antibody suppresses bone resorption by inhibiting osteoclast multinucleation without attenuating bone formation

Anti-resorptive drugs are widely used for the treatment of osteoporosis, but excessive inhibition of osteoclastogenesis can suppress bone turnover and cause the deterioration of bone quality. Sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) is a transmembrane protein expressed on osteoclast precursor cells and mature osteoclasts. Siglec-15 regulates proteins containing immunoreceptor tyrosine-based activation motif (ITAM) domains, which then induce nuclear factor of activated T-cells 1 (NFATc1), a master transcription factor of osteoclast differentiation. Anti-Siglec-15 antibody modulates ITAM signaling in osteoclast precursors and inhibits the maturation of osteoclasts in vitro. However, in situ pharmacological effects, particularly during postmenopausal osteoporosis, remain unclear. Here, we demonstrated that anti-Siglec-15 antibody treatment protected against ovariectomy-induced bone loss by specifically inhibiting the generation of multinucleated osteoclasts in vivo. Moreover, treatment with anti-Siglec-15 antibody maintained bone formation to a greater extent than with risedronate, the first-line treatment for osteoporosis. Intravital imaging revealed that anti-Siglec-15 antibody treatment did not cause a reduction in osteoclast motility, whereas osteoclast motility declined following risedronate treatment. We evaluated osteoclast activity using a pH-sensing probe and found that the bone resorptive ability of osteoclasts was lower following anti-Siglec-15 antibody treatment compared to after risedronate treatment. Our findings suggest that anti-Siglec-15 treatment may have potential as an anti-resorptive therapy for osteoporosis, which substantially inhibits the activity of osteoclasts while maintaining physiological bone coupling.Tsukazaki H., Kikuta J., Ao T., et al. Anti-Siglec-15 antibody suppresses bone resorption by inhibiting osteoclast multinucleation without attenuating bone formation. Bone 152, 116095 (2021); https://doi.org/10.1016/j.bone.2021.116095