The Hayabusa spacecraft successfully recovered dust particles from the surface of near-Earth asteroid 25143 Itokawa. Synchrotron-radiation x-ray diffraction and transmission and scanning electron microscope analyses indicate that the mineralogy and mineral chemistry of the Itokawa dust particles are identical to those of thermally metamorphosed LL chondrites, consistent with spectroscopic observations made from Earth and by the Hayabusa spacecraft. Our results directly demonstrate that ordinary chondrites, the most abundant meteorites found on Earth, come from S-type asteroids. Mineral chemistry indicates that the majority of regolith surface particles suffered long-term thermal annealing and subsequent impact shock, suggesting that Itokawa is an asteroid made of reassembled pieces of the interior portions of a once larger asteroid.

Abstract-On the basis of observations using Cs-corrected STEM, we identified three types of surface modification probably formed by space weathering on the surfaces of Itokawa particles. They are (1) redeposition rims (2-3 nm), (2) composite rims (30-60 nm), and (3) composite vesicular rims (60-80 nm). These rims are characterized by a combination of three zones. Zone I occupies the outermost part of the surface modification, which contains elements that are not included in the unchanged substrate minerals, suggesting that this zone is composed of sputter deposits and/or impact vapor deposits originating from the surrounding minerals. Redeposition rims are composed only of Zone I and directly attaches to the unchanged minerals (Zone III). Zone I of composite and composite vesicular rims often contains nanophase (Fe,Mg)S. The composite rims and the composite vesicular rims have a two-layered structure: a combination of Zone I and Zone II, below which Zone III exists. Zone II is the partially amorphized zone. Zone II of ferromagnesian silicates contains abundant nanophase Fe. Radiation-induced segregation and in situ reduction are the most plausible mechanisms to form nanophase Fe in Zone II. Their lattice fringes indicate that they contain metallic iron, which probably causes the reddening of the reflectance spectra of Itokawa. Zone II of the composite vesicular rims contains vesicles. The vesicles in Zone II were probably formed by segregation of solar wind He implanted in this zone. The textures strongly suggest that solar wind irradiation damage and implantation are the major causes of surface modification and space weathering on Itokawa.

Resistive behaviors at nonzero temperatures (T > 0) reflecting a quantum vortex-glass (VG) transition (the so-called field-tuned superconductor-insulator transition at T = 0) are studied based on a quantum Ginzburg-Landau (GL) action for a s-wave pairing case containing microscopic details. The ordinary dissipative dynamics of the pair-field is assumed on the basis of a consistency between the fluctuation conductance terms excluded from GL approach and an observed negative magnetoresistance. It is shown that the VG contribution, G vg , to 2D conductance becomes insensitive to T at an apparent VG transition field B * vg defined at experimentally accessible temperatures but depends on the repulsive electron-electron interaction, and that, only in the dirty limit with no electron-repulsion, it takes a universal value at low T .Available resistivity data near B * vg are explained based on our results, and an extension of the theory to 3D case is briefly discussed. dissipative dynamics, and hence, a nondissipative dynamics was assumed there. 6) Further, since such a phase-only action is essentially equivalent to the quantum boson action at low energy, possible vortex phases were identified with the corresponding ones of the boson system. However, as in the description of thermal vortex phase diagram at nonzero temperatures, 12) a more microscopic GL approach in which the pair-field yields a dissipative dynamics should be able to explain physical properties systematically even at low temperatures as far as a nontrivial intermediate phase 13) does not occur as a consequence of a phase-only model valid for nongranular films. For instance, the so-called bose insulating state 1, 2) will correspond to the quantum vortex liquid regime 14) with insulating GL fluctuation conductivity.Actually, there are several reasons why the Fisher's argument on the resistive behavior near a FSI transition should be reconsidered theoretically. First, the argument 6) on a universal conductance value at the VG transition field, B = B vg , and on the scaling behavior at T > 0 of resistance is based on consideration and calculations of the fluctuation conductance G s (T = 0, ω → 0) in the disorder-tuned case at 15) B = 0, where ω → 0 means taking the dc limit. However, at a T = 0 criticality, this conductance need not be equal to the quantity 16) G s (T → 0, ω = 0). It is the latter which is measurable in real experiments, while it is the former which is expected to take a universal value as a consequence of a quantum continuous transition. 15) Further, the temperature range over which the presence of a T -independent conductance is suggested is often 1, 3) broad so that the dissipative dynamics, neglected in ref.6, of the pair-field does not seem to be negligible, and thus, it is unclear to what extent taking the T → 0 limit is essential. In addition, the assumption 6) that the derivation of G s (T = 0, ω → 0) at B = 0 is applicable to the nonzero field case is not justified, because the VG critical properties of response quantities are quite d...

The science operations of the spacecraft and remote sensing instruments for the Martian Moon eXploration (MMX) mission are discussed by the mission operation working team. In this paper, we describe the Phobos observations during the first 1.5 years of the spacecraft’s stay around Mars, and the Deimos observations before leaving the Martian system. In the Phobos observation, the spacecraft will be placed in low-altitude quasi-satellite orbits on the equatorial plane of Phobos and will make high-resolution topographic and spectroscopic observations of the Phobos surface from five different altitudes orbits. The spacecraft will also attempt to observe polar regions of Phobos from a three-dimensional quasi-satellite orbit moving out of the equatorial plane of Phobos. From these observations, we will constrain the origin of Phobos and Deimos and select places for landing site candidates for sample collection. For the Deimos observations, the spacecraft will be injected into two resonant orbits and will perform many flybys to observe the surface of Deimos over as large an area as possible. Graphical Abstract

Background and Aims: The coordinated expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) plays a crucial role in tissue remodeling. We investigated the effects of fibroblast growth factor (FGF)-2 on the secretion of MMPs and TIMPs in human intestinal subepithelial myofibroblasts (SEMFs). Methods: The secretion of MMP-s and TIMPs was determined by ELISA or Western blotting. The mRNA expression of MMPs and TIMPs was assessed by Northern blotting. The activating protein (AP)-1-DNA binding activity was evaluated by electrophoretic gel mobility shift assays (EMSA). Results: Unstimulated intestinal SEMFs constitutively secreted MMP-2 and TIMP-2. FGF-2 stimulated MMP-1, MMP-3 and TIMP-1 secretion, but did not affect MMP-2 or TIMP-2 secretion. FGF-2 induced AP-1-DNA binding activity, and the c-Jun/AP-1 inhibitor curcumin attenuated the FGF-2-induced MMP-1, -3 and TIMP-1 mRNA expression. Mitogen-activated protein (MAP) kinase inhibitors (U0126 and PD098059) also blocked the MMP-1, -3 and TIMP-1 secretion. Furthermore, FGF-2 dose-dependently induced FGF-2 mRNA expression in these cells. Conclusions: FGF-2 may be one of important regulatory factors for extracellular matrix turnover via a modulation of MMP and TIMP secretion from SEMFs.