Publications by authors named "Toru Morishita"

Within the framework of the improved quantitative rescattering (QRS) model, we simulate the correlated two-electron momentum distributions (CMDs) for nonsequential double ionization (NSDI) of Ar by elliptically polarized laser pulses with a wavelength of 788 nm at an intensity of 0.7 × 10 W/cm for the ellipticities ranging from 0 to 0.3.

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Dissociative ionization of tetrafluoromethane (CF) in linearly polarized -2 ultrashort intense laser fields (1.4 × 10 W/cm, 800 and 400 nm) has been investigated by three-dimensional momentum ion imaging. The spatial distribution of produced by CF → + F + e exhibited a clear asymmetry with respect to the laser polarization direction.

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Using the improved quantitative rescattering (QRS) model, we simulate the correlated two-electron momentum distributions (CMD) for nonsequential double ionization (NSDI) of Ar by near-single-cycle laser pulses with a wavelength of 750 nm at an intensity of 2.8 × 10 W/cm. With the accurate cross sections obtained from fully quantum mechanical calculations for both electron impact excitation and electron impact ionization of Ar, we unambiguously identify the contributions from recollision direct ionization (RDI) and recollision excitation with subsequent ionization (RESI).

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Using the quantitative rescattering model, we simulate the correlated two-electron momentum distributions for nonsequential double ionization of helium by 800 nm laser pulses at intensities in the range of (2 - 15) × 10 W/cm. The experimentally observed V-shaped structure at high intensities [A. Rudenko et al.

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The seeded Free-Electron Laser (FEL) FERMI is the first source of short-wavelength light possessing the full coherence of optical lasers, together with the extreme power available from FELs. FERMI provides longitudinally coherent radiation in the Extreme Ultraviolet and soft x-ray spectral regions, and therefore opens up wide new fields of investigation in physics. We first propose experiments exploiting this property to provide coherent control of the photoionization of neon and helium, carry out numerical calculations to find optimum experimental parameters, and then describe how these experiments may be realized.

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Perfluorocarboxylic acids (PFCAs) including perfluorooctanoic acid (PFOA) are environmental pollutants showing high accumulation, thermochemical stability and hepatocarcinogenicity. Peroxisome proliferator-activated receptor α is suggested to mediate their toxicities, but the precise mechanism remains unclear. Previous reports also imply a possible role of constitutive androstane receptor (CAR), a key transcription factor for the xenobiotic-induced expression of various genes involved in drug metabolism and disposition as well as hepatocarcinogenesis.

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We revisit the concept of near-forward rescattering strong-field photoelectron holography introduced by Y. Huismans et al. [Science 331, 61 (2011)].

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Tunneling-ionization imaging of photoexcitation of NO has been demonstrated by using few-cycle near-infrared intense laser pulses (8 fs, 800 nm, 1.1×10^{14}  W/cm^{2}). The ion image of N^{+} fragment ions produced by dissociative ionization of NO in the ground state, NO (X^{2}Π,2π)→NO^{+}+e^{-}→N^{+}+O+e^{-}, exhibits a characteristic momentum distribution peaked at 45° with respect to the laser polarization direction.

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We show that a returning electron wave packet in high-order harmonic generation (HHG) with midinfrared laser pulses converges to a universal limit for a laser wavelength above about 3 μm. The results are consistent among the different methods: a numerical solution of the time-dependent Schrödinger equation, the strong-field approximation, and the quantum orbits theory. We further analyze how the contribution from different electron "trajectories" survives the macroscopic propagation in the medium.

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Recently, using midinfrared laser-induced electron diffraction (LIED), snapshots of a vibrating diatomic molecule on a femtosecond time scale have been captured [C.I. Blaga et al.

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We extract large-angle elastic differential cross sections (DCSs) for electrons scattering from partially aligned O2+ and CO2+ molecules using rescattering photoelectrons generated by infrared laser pulses. The extracted DCSs are in good agreement with those calculated theoretically, demonstrating that accurate DCSs for electron-ion scattering can be extracted from the laser-induced rescattering spectra, thus paving the way for dynamic imaging of chemical reactions by rescattering photoelectron spectroscopy.

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We investigate the momentum and energy distributions of the two electrons in multiphoton double ionization of He by intense attosecond xuv pulses, based on a two-dimensional model. Two different patterns of the momentum distributions are identified, corresponding to the uncorrelated and correlated channels, respectively. Our analysis of the electron correlations focuses on two-photon and three-photon double ionization processes for different pulse durations and for different time delays after the pulses.

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We report herein a very rare case of semitendinosus tear that formed a tumor in the popliteal region after not having recovered as a result of only being instructed to rest. The soft tissue tumor was discovered on ultrasonography 4 months after pain and sensation of discomfort appeared in the popliteal region. We considered this symptom as dependent on the presence of the tumor and selected surgical treatment.

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A very slow electron is shown to emerge when an intense high-frequency laser pulse is applied to a hydrogen negative ion. This counterintuitive effect cannot be accounted for by multiphoton or tunneling ionization mechanisms. We explore the effect and show that in the high-frequency regime the atomic electron is promoted to the continuum via a nonadiabatic transition caused by slow deformation of the dressed potential that follows a variation of the envelope of the laser pulse.

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In clinical cases, many orthopaedists have been troubled with bone fragility, such as fractures after devitalization therapy for bone tumour, pathological fractures and metastatic tumours. The aim of this study was to determine whether loss of osteogenic capacity of devitalized autologous bones can be rescued using cultured bone marrow-derived mesenchymal cells. A devitalized bone model was produced from rat femur by irradiation and three groups were prepared: intact bone, irradiated bone and irradiated bone combined with cultured mesenchymal cells.

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By analyzing accurate theoretical results from solving the time-dependent Schrödinger equation of atoms in few-cycle laser pulses, we established the general conclusion that laser-generated high-energy electron momentum spectra and high-order harmonic spectra can be used to extract accurate differential elastic scattering and photo-recombination cross sections of the target ion with free electrons, respectively. Since both electron scattering and photoionization (the inverse of photo-recombination) are the conventional means for interrogating the structure of atoms and molecules, this result implies that existing few-cycle infrared lasers can be implemented for ultrafast imaging of transient molecules with temporal resolution of a few femtoseconds.

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Unlabelled: BACKGROUND DATA AND OBJECTIVES: We present here a case report of a patient with metaphyseal osteosarcoma with a preserved epiphysis and reconstructed by a vascularized fibular graft and hydroxyapatite composites.

Methods: The case was a 14-year-old boy, who had osteosarcoma in the proximal tibia. After the diagnosis was confirmed by biopsy, the patient immediately received preoperative chemotherapy including high-dose Methotrexate, Cisplatin and Doxrubicin.

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Using attosecond light pulses to doubly ionize a two-electron wave packet of helium, we showed that the time-resolved correlated motion of the two electrons can be probed by measuring their six-dimensional momentum distributions. For simple wave packets, we showed that the measured momenta, when analyzed in appropriate coordinates, can reveal the stretching, the rotational, and the bending vibrational modes of their joint motion in momentum space, in spite of the Coulomb distortion in the final states.

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We report here a 16-year-old male with primitive neuroectodermal tumor (PNET)-associated probable microangiopathy with multiple bone metastases. Laboratory findings excluded the possibility of amegakaryocytic or immune thrombocytopenia and/or disseminated intravascular coagulation. He was first treated with plasma-exchange (PE), followed by platelet transfusions, steroid pulse therapy and combined chemotherapy.

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Recent studies have advocated the genotypic and phenotypic delineation of a novel Ewing's sarcoma histologic variant showing epithelial features defined as "adamantinoma-like Ewing's sarcoma". We described an 18-year-old girl with a primary small round-cell sarcoma of the right tibia showing polyphenotypic differentiation with epithelioid features. The neoplastic cells had mainly round or oval nuclei with fine chromatin with a portion of epithelial arrangements.

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A novel approach to the treatment of bone tumors using tissue-engineered implants is reported in this study. The number of mesenchymal stem cells (MSCs) obtained from each patient's bone marrow cells was first increased, and the MSCs were forced to differentiate into osteoblasts followed by bone matrix formation on hydroxyapatite (HA) ceramics. The strong osteogenic ability of the implants, as evidenced by high osteoblastic activity, was confirmed.

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Plexiform schwannoma is a rare benign neurogenic tumour; we report a case that arose in the ulnar nerve of a 59-year-old woman. Exploration showed a continuous multinodular tumour that involved the ulnar nerve from the hand to the upper arm; the length of the tumour was 35 cm.

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Flavopiridol is the potent inhibitor of cdks sharing its function with endogenous cdk inhibitors, and causes arrest at both the G1 and G2 phases of the cell cycle resulting in apoptosis in various tumor cell lines. Cyclin-dependent kinase inhibitor p16INK4a induces cell cycle arrest in G1 or G2 or both, and is inactivated in many malignant tumors. In this study, we focused on the effects of flavopiridol on chemically-induced rat lung adenocarcinoma, osteosarcoma and malignant fibrous histiocytoma (MFH) cell lines showing different pattern of p16INK4a status.

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STI571 is a 2-phenylaminopyrimide derivative that was designed as an Abl tyrosine kinase inhibitor, but it is also effective against platelet-derived growth factor receptor (PDGFR) and c-Kit tyrosine kinase. Recent studies have demonstrated that STI571 inhibits the growth of several tumors in which PDGF or c-kit play an important role in tumor pathogenesis. We have recently established rat osteosarcoma and malignant fibrous histiocytoma (MFH) cell lines.

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Cytokines are considered to play an important role in tumor pathogenesis and progression, and recent studies have demonstrated that a variety of forms, including interleukins (ILs) and transforming growth factor-beta(s) (TGF-beta(s)), may regulate tumors. In the present study, the expression of TGF-beta isoforms and ILs was investigated in cell lines from a rat osteosarcoma and a malignant fibrous histiocytoma (MFH), both established from transplantable tumors induced by 4-(hydroxyamino) quinoline 1-oxide (4-HAQO) in syngeneic F344 male rats. The results of a multiprobe RNase protection assay showed TGF-beta1 expression to be remarkably elevated, with no TGF-beta2 and beta3 detectable in MFH cells, while TGF-beta1 and -beta2 were found to be moderately and TGF-beta3 weakly expressed in osteosarcoma lines.

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