Near-Infrared Imaging Polarimetry of Inner Region of GG Tau A Disk

By performing non-masked polarization imaging with Subaru/HiCIAO, polarized scattered light from the inner region of the disk around the GG Tau A system was successfully detected in the $H$ band with a spatial resolution of approximately 0.07\arcsec, revealing the complicated inner disk structures around this young binary. This paper reports the observation of an arc-like structure to the north of GG Tau Ab and part of a circumstellar structure that is noticeable around GG Tau Aa extending to a distance of approximately 28 AU from the primary star. The speckle noise around GG Tau Ab constrains its disk radius to <13 AU. Based on the size of the circumbinary ring and the circumstellar disk around GG Tau Aa, the semi-major axis of the binary's orbit is likely to be 62 AU. A comparison of the present observations with previous ALMA and near-infrared (NIR) H$_2$ emission observations suggests that the north arc could be part of a large streamer flowing from the circumbinary ring to sustain the circumstellar disks. According to the previous studies, the circumstellar disk around GG Tau Aa has enough mass and can sustain itself for a duration sufficient for planet formation; thus, our study indicates that planets can form within close (separation $\lesssim$ 100 AU) young binary systems.Comment: Accepted for publication in AJ, 12 pages, 5 figure

Cellular Basis of Tissue Regeneration by Omentum

The omentum is a sheet-like tissue attached to the greater curvature of the stomach and contains secondary lymphoid organs called milky spots. The omentum has been used for its healing potential for over 100 years by transposing the omental pedicle to injured organs (omental transposition), but the mechanism by which omentum helps the healing process of damaged tissues is not well understood. Omental transposition promotes expansion of pancreatic islets, hepatocytes, embryonic kidney, and neurons. Omental cells (OCs) can be activated by foreign bodies in vivo. Once activated, they become a rich source for growth factors and express pluripotent stem cell markers. Moreover, OCs become engrafted in injured tissues suggesting that they might function as stem cells

Genomics of alkaliphiles

Alkalinicity presents a challenge for life due to a “reversed” proton gradient that is unfavourable to many bioenergetic processes across the membranes of microorganisms. Despite this, many bacteria, archaea, and eukaryotes, collectively termed alkaliphiles, are adapted to life in alkaline ecosystems and are of great scientific and biotechnological interest due to their niche specialization and ability to produce highly stable enzymes. Advances in next-generation sequencing technologies have propelled not only the genomic characterization of many alkaliphilic microorganisms that have been isolated from nature alkaline sources but also our understanding of the functional relationships between different taxa in microbial communities living in these ecosystems. In this review, we discuss the genetics and molecular biology of alkaliphiles from an “omics” point of view, focusing on how metagenomics and transcriptomics have contributed to our understanding of these extremophiles.https://link.springer.com/bookseries/10hj2021BiochemistryGeneticsMicrobiology and Plant Patholog

Second harmonic generation in the Weyl semimetal TaAs from a quantum kinetic equation

We classify the sources of second harmonic generation (SHG) of the Weyl semimetal TaAs by collisionless quantum kinetic equation into three kinds: i.e., injection current from the canonical band dispersion, shift current from a gauge invariant shift vector, and anomalous current from Berry curvature associated with the Fermi surface. Importantly, by using the realistic band model for TaAs, we predict that the SHG in TaAs is predominately contributed by the shift current, while the anomalous current has a minute contribution when the Weyl point is exactly located on the Fermi surface. Moreover, we highlight that the SHG contributed by the anomalous current decays fast with the increasing frequency of incident photons, and could be enhanced by proper electron or hole doping of TaAs.Published versio

Structure of the human M2 muscarinic acetylcholine receptor bound to an antagonist

認知症や心機能の抑制に関係する受容体の立体構造を世界で初めて解明－より効果的で副作用のない治療薬の探索・設計が可能に－. 京都大学プレスリリース.2012-01-26.The parasympathetic branch of the autonomic nervous system regulates the activity ofmultiple organ systems.Muscarinic receptors are G-protein-coupled receptors that mediate the response to acetylcholine released from parasympathetic nerves1–5. Their role in the unconscious regulation of organ and central nervous system function makes them potential therapeutic targets for a broad spectrum of diseases. The M2 muscarinic acetylcholine receptor (M2 receptor) is essential for the physiological control of cardiovascular function through activation of G-protein-coupled inwardly rectifying potassiumchannels, and is of particular interest because of its extensive pharmacological characterization with both orthosteric and allosteric ligands.Herewe report the structure of the antagonistbound humanM2 receptor, the first human acetylcholine receptor to be characterized structurally, to our knowledge. The antagonist 3-quinuclidinyl-benzilate binds in the middle of a long aqueous channel extending approximately two-thirds through the membrane. The orthosteric binding pocket is formed by amino acids that are identical in all five muscarinic receptor subtypes, and shares structural homology with other functionally unrelated acetylcholine binding proteins from different species. A layer of tyrosine residues forms an aromatic cap restricting dissociation of the bound ligand. A binding site for allosteric ligands has been mapped to residues at the entrance to the binding pocket near this aromatic cap. The structure of the M2 receptor provides insights into the challenges of developing subtype-selective ligands for muscarinic receptors and their propensity for allosteric regulation