Petrology and mineralogy of the Yamato-86720 carbonaceous chondrite

Phyllosilicate clasts in Yamato-86720 consist mainly of dehydrated serpentine (or chlorite) and sodian talc (or saponite) components, which are the most homogeneous in chemical compositions among those in CM chondrites. They were produced from chondrules by intense hydrous alteration, resulting in the homogeneous composition of the phyllosilicates. Metal spherules and troilite grains in original chondrules have also altered to ovoidal phyllosilicate inclusions and unusual carbonate-phyllosilicates inclusions, respectively. The CaO content of the original chondrules was retained within them as the unusual carbonate-phyllosilicate inclusions, which resulted in the low CaO content of the Y-86720 matrix. The matrix is different in composition from the clast phyllosilicates, suggesting that the two were produced in conditions different from each other. Pyrrhotite grains in clasts and matrix have altered probably to ferrihydrite, which have produced Fe-rich halos around the pyrrhotite grains after the agglomeration of Y-86720 and prior to a heating event. The heating event took place in the final stage of the chondrite formation, resulting in dehydration of phyllosilicates and reduction of ferrihydrite to Co-Ni-poor kamacite

Single-photon interference over 150-km transmission using silica-based integrated-optic interferometers for quantum cryptography

We have demonstrated single-photon interference over 150 km using time-division interferometers for quantum cryptography, which were composed of two integrated-optic asymmetric Mach-Zehnder interferometers, and balanced gated-mode photon detectors. The observed fringe visibility was more than 80% after 150-km transmission.Comment: 10 pages, 2 figures, submitted to Electronics Letter

Antarctic primitive achondrites Yamato-74025, -75300, and -75305:Their mineralogy, thermal history and the relevance to winonaite

Three Antarctic primitive achondrites, Yamato (Y)-74025,-75300,and -75305 were mineralogically and chemically studied. They consist of anhedral to subhedral silicate and opaque minerals. The major constituent minerals are typical of equilibrated ordinary chondrites. However, they do not have any relic of chondrule, and the presence of various accessory minerals, such as K-feldspar, schreibersite, daubreelite, phosphate, Nb-bearing rutile, and magnesiochromite, characterizes these meteorites. Y-75305 has a composite grain containing Cu, Mn, and S, probably consisting of alabandite, an unknown Mn-bearing Cu-sulfide, and digenite. Y-74025 has a REE pattern typical of chondrite. Siderophile elements in Y-74025 are depleted relative to Cl chondrites, which is consistent with poor abundance of Fe-Ni metal in Y-74025. Holocrystalline texture, homogeneous mineral compositions, and high equilibration temperatures for pyroxenes, suggest that these primitive achondrites experienced high-temperature metamorphism. Mineralogical and chemical characteristics suggest that they resemble Winona-like meteorites (winonaites). The compositions of pyroxene and olivine, and accessory minerals suggest that winonaites formed under an intermediate redox condition between E-chondrites and Acapulco-like primitive achondrites. The abundance of troilite and Fe-Ni metal varies widely. The metal-sulfide fractions of winonaites probably melted and fractionated, although silicate fractions of winonaites do not have any evidence for melting

Vertical orientation with a narrow distribution of helical peptides immobilized on a quartz substrate by stereocomplex formation

Second-harmonic generation (SHG) of a donor–π–acceptor (D–π–A) chromophore attached to helical peptides was used for the evaluation of the self-assembled monolayer (SAM) structure of a stereocomplex of helical peptides. A stereocomplex SAM of a left-handed helical conjugate (D17) and a right-handed helical conjugate (L17) showed an SHG intensity four times larger than a stereocomplex SAM of a left-handed helical D17 and a right-handed helical peptide without the D–π–A chromophore (LA16), which agrees well with dependence of SHG intensities on the surface densities of the D–π–A chromophore. The SHG intensities of enantiopure SAMs of D17 and L17 are, however, 47% and 27% of the stereocomplex SAM of D17 and L17, respectively. These differences can be explained only after taking a larger distribution of the tilt angle of the chromophore in the enantiopure SAMs than in the stereocomplex SAM of D17 and L17. On the basis of these analyses, it is concluded that the stereocomplex SAM of a left-handed helix and a right-handed helix constitutes a well-ordered structure, where the tilt angle of the helical peptide from the surface normal becomes small with a narrow distribution due to stereocomplex formation

Petrologic subtypes of CM chondrites: Reinvestigation and proposal of subtypes 3.0 to 2.8

The Tenth Symposium on Polar Science/Poster presentations: [OA] Antarctic meteorites, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc

Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

This paper reports very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ~10 pc. The convex radio spectrum is stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age of the order of ~100 years as a radio source, according to an observed correlation between linear size and peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.Comment: 7 pages, 2 figures, 2 tables, accepted for publication in PAS

Risk of bleeding and repeated bleeding events in prasugrel-treated patients: a review of data from the Japanese PRASFIT studies

Prasugrel is a third-generation thienopyridine that achieves potent platelet inhibition with less pharmacological variability than other thienopyridines. However, clinical experience suggests that prasugrel may be associated with a higher risk of de novo and recurrent bleeding events compared with clopidogrel in Japanese patients undergoing percutaneous coronary intervention (PCI). In this review, we evaluate the risk of bleeding in Japanese patients treated with prasugrel at the doses (loading/maintenance doses: 20/3.75 mg) adjusted for Japanese patients, evaluate the risk factors for bleeding in Japanese patients, and examine whether patients with a bleeding event are at increased risk of recurrent bleeding. This review covers published data and new analyses of the PRASFIT (PRASugrel compared with clopidogrel For Japanese patIenTs) trials of patients undergoing PCI for acute coronary syndrome or elective reasons. The bleeding risk with prasugrel was similar to that observed with the standard dose of clopidogrel (300/75 mg), including when bleeding events were re-classified using the Bleeding Academic Research Consortium criteria. The pharmacodynamics of prasugrel was not associated with the risk of bleeding events. The main risk factors for bleeding events were female sex, low body weight, advanced age, and presence of diabetes mellitus. Use of a radial puncture site was associated with a lower risk of bleeding during PCI than a femoral puncture site. Finally, the frequency and severity of recurrent bleeding events during continued treatment were similar between prasugrel and clopidogrel. In summary, this review provides important insights into the risk and types of bleeding events in prasugrel-treated patients. Trial registration numbers: JapicCTI-101339 and JapicCTI-111550