Noble gases and K-Ar ages of five Rumuruti chondrites Yamato(Y)-75302, Y-791827, Y-793575, Y-82002, and Asuka-881988

Noble gases and K concentrations have been determined for aliquot samples prepared from the five Antarctic R-chondrites Yamato (Y)-75302,Y-791827,Y-793575,Y-82002,and Asuka (A)-881988. K-Ar ages of about 4.2Ga were obtained for Y-75302,Y-791827,Y-793575 and A-881988,while Y-82002 showed a slightly younger age of 3.9Ga. The Y-75302,Y-791827 and Y-82002 are enriched in solar light noble gases. Four meteorites Y-75302,Y-791827,Y-82002 and A-881988 have cosmic-ray exposure ages of about 20Ma, while the age of Y-793575 is about 7Ma. Based on the noble gas compositions and K-Ar ages, Y-75302 and Y-791827 are probably paired and Y-82002 may belong to this pair. Relatively high and variable ^Xe/^Xe ratios between 2-3.7 as well as enrichments of heavier Xe isotopes were observed in all R-chondrites

Cosmic-ray exposure ages of enstatite chondrites

Eleven enstatite (E-) chondrites were analyzed for abundances and isotopic ratios of noble gases by total melting. Light noble gases, He, Ne and Ar are discussed. We obtained cosmic-ray exposure ages (T^) based on cosmogenic ^Ne that are divided into two groups, below 15 Myr and above 40 Myr. Both ranges of T^ contain various petrologic-types of E-chondrites. Isotopic ratios and concentration of Ne for Yamato (Y)-8414 and -86004 are almost the same, which suggests that they are from a common fragment. Identical exposure age T^ of 10 Myr for Y-8414 and -86004 supports their pairing. The pairing for Y-8414 and -86004 based on noble-gas signatures and T^ is consistent with their petrologic similarities. Pairing for Y-792959 and -793161 is also suggested by their similarities in mineral compositions, their close sampling location and the same petrologic-type. However, there are discrepancies in He and Ar contents between the two samples, which fails to support their pairing. Including literature data, the exposure ages show no systematic correlation with petrologic type. Additionally, both EH-and EL-chondrites are found in both two peaks of T^. The exposure age distribution has no implications about the structure of E-chondrite parent body. The parent body of E-chondrites has possibly lost the original structure after many collisions in the early solar system evolution

Paradoxical increase in the PPG amplitude

Background : Although an increase in sympathetic nerve activity is generally associated with a decrease in the photoplethysmography (PPG) amplitude, the present case study demonstrates that nociceptive stimuli, such as tracheal intubation, paradoxically induce an increase in PPG amplitude. To the best of our knowledge, this is the first study to capture an increase in the PPG amplitude in response to sympathetic nerve activation. Case presentation : A 73-year-old woman underwent open surgery. Following anesthesia induction, tracheal intubation was performed, which resulted in increased heart rate and raised blood pressure. While nociception usually decreases the PPG amplitude, the opposite was found. Conversely, the vascular stiffness K value, our research group’s unique monitoring method to quantify the strength of sympathetic activity, increased reflecting increased peripheral vascular resistance. Conclusions : We report a paradoxical case of increased PPG amplitude following tracheal intubation. It is important to note that the PPG amplitude does not always decrease with nociceptive stimuli

THE INTERSECTION POLYNOMIALS OF A VIRTUAL KNOT III: CHARACTERIZATION

We introduced three kinds of invariants of a virtual knot called the first, second, and third intersection polynomials in the first paper [5]. We also gave the connected sum formulae of the intersection polynomials in the second paper [6]. In this paper, we give characterizations of intersection polynomials

Monoaxial Dzyaloshinskii-Moriya interaction-induced topological Hall effect in a new chiral-lattice magnet GdPt2_2B

We investigate the topological Hall effect (THE) in the monoaxial chiral crystal GdPt$_2$B, a recently discovered compound that exhibits putative helimagnetism below 87 K. The distinct THE was observed in GdPt2B in the magnetically ordered state. The scaling relations for anomalous and topological Hall conductivities differed from those of conventional models based on the scattering process. We further demonstrate the clear scaling behavior of the THE in a wide temperature range, which we attribute to the monoaxial Dzyaloshinskii-Moriya (DM) interaction under external magnetic fields perpendicular to the screw axis. The THE induced by the monoaxial DM interaction as well as the THE in a monoaxial chiral crystal of f-electron system are demonstrated in this study.Comment: 6 pages, 4 figures. To be published in Phys. Rev.

Fermi surface topology and electronic transport properties of a chiral crystal NbGe2_2 with strong electron-phonon interaction

We report the electronic structures and transport properties of a chiral crystal NbGe$_2$, which is a candidate for a coupled electron-phonon liquid. The electrical resistivity and thermoelectric power of NbGe$_2$ exhibit clear differences compared to those of NbSi2 even though both niobium ditetrelides are isostructural and isoelectronic. We discuss the intriguing transport properties of NbGe$_2$ based on a van Hove-type singularity in the density of states. The analysis of de Haas-van Alphen oscillations measured by the field modulation and magnetic torque methods reveals the detailed shape of the Fermi surface of NbGe$_2$ by comparison with the results of energy band structure calculations using a local density approximation. The electron and hole Fermi surfaces of NbGe$_2$ split into two because of the anti-symmetric spin-orbit interaction. The temperature dependence of quantum oscillations indicates that the effective mass is isotropically enhanced in NbGe$_2$ due to strong electron-phonon interaction.Comment: 9 pages, 7 figures, To be published in Phys. Rev.

Laparoscopic splenectomy for a large multilocular splenic cyst with elevated CA19-9: Report of a case

AbstractINTRODUCTIONBecause splenic cysts are rare, a definitive treatment regime for these cysts remains unclear. We report a case of a large multilocular splenic cyst with elevated carbohydrate antigen 19-9 (CA19-9) levels, which was successfully treated with laparoscopic splenectomy.PRESENTATION OF CASEA 22-year-old female was admitted to our hospital with severe left upper abdominal pain. Serum CA19-9 level was mildly elevated (65U/ml). Computed tomography revealed a 25-cm long spleen with multilocular cystic lesions, for which an emergency laparoscopic splenectomy was performed. Histological findings revealed that the lesion was a benign true cyst, and immunostaining analyses showed that the epithelium was CA19-9-positive.DISCUSSIONAlthough some spleen-preserving approaches have been reportedly used, splenic cyst recurrence usually occurs in true cyst cases, wherein the cyst is incompletely removed. Most reported cases of splenic cysts producing CA19-9 are true cysts.CONCLUSIONThe treatment approach should be decided on the basis of the type, shape, location, and even CA19-9 levels of the splenic cyst

Mimicking angiogenic microenvironment of alveolar soft-part sarcoma in a microfluidic coculture vasculature chip

胞巣状軟部肉腫のオンチップモデルにより血管新生メカニズムを明らかに --Microphysiological systems (MPS)を活用した血管新生標的分子の評価--. 京都大学プレスリリース. 2024-03-19.Alveolar soft-part sarcoma (ASPS) is a slow-growing soft tissue sarcoma with high mortality rates that affects adolescents and young adults. ASPS resists conventional chemotherapy; thus, decades of research have elucidated pathogenic mechanisms driving the disease, particularly its angiogenic capacities. Integrated blood vessels that are rich in pericytes (PCs) and metastatic potential are distinctive of ASPS. To mimic ASPS angiogenic microenvironment, a microfluidic coculture vasculature chip has been developed as a three-dimensional (3D) spheroid composed of mouse ASPS, a layer of PCs, and endothelial cells (ECs). This ASPS-on-a-chip provided functional and morphological similarity as the in vivo mouse model to elucidate the cellular crosstalk within the tumor vasculature before metastasis. We successfully reproduce ASPS spheroid and leaky vessels representing the unique tumor vasculature to assess effective drug delivery into the core of a solid tumor. Furthermore, this ASPS angiogenesis model enabled us to investigate the role of proteins in the intracellular trafficking of bioactive signals from ASPS to PCs and ECs during angiogenesis, including Rab27a and Sytl2. The results can help to develop drugs targeting the crosstalk between ASPS and the adjacent cells in the tumoral microenvironment