Collinear and triangular solutions to the coplanar and circular three-body problem in the parameterized post-Newtonian formalism

This paper investigates the coplanar and circular three-body problem in the parameterized post-Newtonian (PPN) formalism, for which we focus on a class of fully conservative theories characterized by the Eddington-Robertson parameters $\beta$ and $\gamma$. It is shown that there can still exist a collinear equilibrium configuration and a triangular one, each of which is a generalization of the post-Newtonian equilibrium configuration in general relativity. The collinear configuration can exist for arbitrary mass ratio, $\beta$, and $\gamma$. On the other hand, the PPN triangular configuration depends on the nonlinearity parameter $\beta$ but not on $\gamma$. For any value of $\beta$, the equilateral configuration is possible, if and only if three finite masses are equal or two test masses orbit around one finite mass. For general mass cases, the PPN triangle is not equilateral as in the post-Newtonian case. It is shown also that the PPN displacements from the Lagrange points in the Newtonian gravity $L_1$, $L_2$ and $L_3$ depend on $\beta$ and $\gamma$, whereas those to $L_4$ and $L_5$ rely only on $\beta$.Comment: 8 pages, 2 figures, title and text improved, Eq. (45) expanded, typos corrected, accepted for PR

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

Promoting Effect of Cerium Oxide on the Catalytic Performance of Yttrium Oxide for Oxidative Coupling of Methane

The promoting effect of CeO2 on the catalytic performance of Y2O3, which is moderately active catalyst, for the oxidative coupling of methane (OCM) reaction was investigated. The addition of CeO2 into Y2O3 by coprecipitation method caused a significant increase in not only CH4 conversion but also C2 (C2H6/C2H4) selectivity in the OCM reaction. C2 yield at 750 °C was increased from 5.6% on Y2O3 to 10.2% on 3 mol% CeO2/Y2O3. Further increase in the CeO2 loading caused an increase in non-selective oxidation of CH4 to CO2. A good correlation between the catalytic activity for the OCM reaction and the amount of H2 consumption for the reduction of surface/subsurface oxygen species in the H2-TPR profile was observed, suggesting the possibility that highly dispersed CeO2 particles act as catalytically active sites in the OCM reaction. The 16O/18O isotopic exchange reaction suggested that the beneficial role of CeO2 in the OCM reaction is to promote the formation of active oxygen species via the simple hetero-exchange mechanism, resulting in the promotion of CH4 activation

The Dynamical State of the Serpens South Filamentary Infrared Dark Cloud

We present the results of N_2H^+ (J = 1-0) observations toward Serpens South, the nearest cluster-forming, infrared dark cloud. The physical quantities are derived by fitting the hyperfine structure of N_2H^+. The Herschel and 1.1 mm continuum maps show that a parsec-scale filament fragments into three clumps with radii of 0.1-0.2 pc and masses of 40-230 M_☉. We find that the clumps contain smaller-scale (~0.04 pc) structures, i.e., dense cores. We identify 70 cores by applying CLUMPFIND to the N_2H^+ data cube. In the central cluster-forming clump, the excitation temperature and line-width tend to be large, presumably due to protostellar outflow feedback and stellar radiation. However, for all the clumps, the virial ratios are evaluated to be 0.1-0.3, indicating that the internal motions play only a minor role in the clump support. The clumps exhibit no free fall but exhibit low-velocity infall, and thus the clumps should be supported by additional forces. The most promising force is the globally ordered magnetic field observed toward this region. We propose that the Serpens South filament was close to magnetically critical and ambipolar diffusion triggered the cluster formation. We find that the northern clump, which shows no active star formation, has a mass and radius comparable to the central cluster-forming clump and is therefore a likely candidate of a pre-protocluster clump. The initial condition for cluster formation is likely to be a magnetically supported clump of cold, quiescent gas. This appears to contradict the accretion-driven turbulence scenario, for which the turbulence in the clumps is maintained by the accretion flow

RAISE-3 for Agile On-Orbit Demonstration of Innovative Satellite Technologies: Mission Definition and Conceptual Design

The Japan Aerospace Exploration Agency (JAXA) has selected on-orbit demonstration missions for the Innovative Satellite Technology Demonstration-3 project in May 2020, as part of the Innovative Satellite Technology Demonstration Program. Seven on-orbit demonstration missions were selected in a category of parts, components and subsystems and those missions will be demonstrated onboard the RApid Innovative payload demonstration SatellitE-3 (RAISE-3). This 100kg-class satellite developed by JAXA is a flagship of the Innovative Satellite Technology Demonstration-3 fleet. This paper describes an overview of the demonstration missions and system specifications of RAISE-3, as well as results of conceptual design of the satellite and a partial application of digital development process to an initial phase of the project. Further, project plan and technical challenges to be studied in a project implementation phase are also discussed

Structural basis for the substrate recognition of aminoglycoside 7′′-phosphotransferase-Ia from Streptomyces hygroscopicus

Hygromycin B (HygB) is one of the aminoglycoside antibiotics, and it is widely used as a reagent in molecular-biology experiments. Two kinases are known to inactivate HygB through phosphorylation: aminoglycoside 7′′-phosphotransferase-Ia [APH(7′′)-Ia] from Streptomyces hygroscopicus and aminoglycoside 4-phosphotransferase-Ia [APH(4)-Ia] from Escherichia coli. They phosphorylate the hydroxyl groups at positions 7′′ and 4 of the HygB molecule, respectively. Previously, the crystal structure of APH(4)-Ia was reported as a ternary complex with HygB and 5′-adenylyl-β,γ-imidodiphosphate (AMP-PNP). To investigate the differences in the substrate-recognition mechanism between APH(7′′)-Ia and APH(4)-Ia, the crystal structure of APH(7′′)-Ia complexed with HygB is reported. The overall structure of APH(7′′)-Ia is similar to those of other aminoglycoside phosphotransferases, including APH(4)-Ia, and consists of an N-terminal lobe (N-lobe) and a C-terminal lobe (C-lobe). The latter also comprises a core and a helical domain. Accordingly, the APH(7′′)-Ia and APH(4)-Ia structures fit globally when the structures are superposed at three catalytically important conserved residues, His, Asp and Asn, in the Brenner motif, which is conserved in aminoglycoside phosphotransferases as well as in eukaryotic protein kinases. On the other hand, the phosphorylated hydroxyl groups of HygB in both structures come close to the Asp residue, and the HygB molecules in each structure lie in opposite directions. These molecules were held by the helical domain in the C-lobe, which exhibited structural differences between the two kinases. Furthermore, based on the crystal structures of APH(7′′)-Ia and APH(4)-Ia, some mutated residues in their thermostable mutants reported previously were located at the same positions in the two enzymes