199 research outputs found

    Dilaton Gravity in 2+ϵ2+\epsilon Dimensions

    Full text link
    Quantum theory of dilaton gravity is studied in 2+ϵ2+\epsilon dimensions. Divergences are computed and renormalized at one-loop order. The mixing between the Liouville field and the dilaton field eliminates 1/ϵ1/\epsilon singularity in the Liouville-dilaton propagator. This smooth behavior of the dilaton gravity theory in the ϵ0\epsilon \rightarrow 0 limit solves the oversubtraction problem which afflicted the higher orders of the Einstein gravity in 2+ϵ2+\epsilon dimensions. As a nontrivial fixed point, we find a dilaton gravity action which can be transformed to a CGHS type action.Comment: 26 pages, TIT/HEP-254, STUPP-94-13

    Isotropic photonic band gap and anisotropic structures in transmission spectra of two-dimensional 5-fold and 8-fold symmetric quasiperiodic photonic crystals

    Get PDF
    We measured and calculated transmission spectra of two-dimensional quasiperiodic photonic crystals (PCs) based on a 5-fold (Penrose) or 8-fold (octagonal) symmetric quasiperiodic pattern. The photonic crystal consisted of dielectric cylindrical rods in air placed normal to the basal plane on vertices of tiles composing the quasiperiodic pattern. An isotropic photonic band gap (PBG) appeared in the TM mode, where electric fields were parallel to the rods, even when the real part of a dielectric constant of the rod was as small as 2.4. An isotropic PBG-like dip was seen in tiny Penrose and octagonal PCs with only 6 and 9 rods, respectively. These results indicate that local multiple light scattering within the tiny PC plays an important role in the PBG formation. Besides the isotropic PBG, we found dips depending on the incident angle of the light. This is the first report of anisotropic structures clearly observed in transmission spectra of quasiperiodic PCs. Based on rod-number and rod-arrangement dependence, it is thought that the shapes and positions of the anisotropic dips are determined by global multiple light scattering covering the whole system. In contrast to the isotropic PBG due to local light scattering, we could not find any PBGs due to global light scattering even though we studied transmission spectra of a huge Penrose PC with 466 rods.Comment: One tex file for manuscript and 12 PNG files for figures consisting of Fig.1a-d, 2,3, ...

    Tree of motility – A proposed history of motility systems in the tree of life

    Get PDF
    Motility often plays a decisive role in the survival of species. Five systems of motility have been studied in depth: those propelled by bacterial flagella, eukaryotic actin polymerization and the eukaryotic motor proteins myosin, kinesin and dynein. However, many organisms exhibit surprisingly diverse motilities, and advances in genomics, molecular biology and imaging have showed that those motilities have inherently independent mechanisms. This makes defining the breadth of motility nontrivial, because novel motilities may be driven by unknown mechanisms. Here, we classify the known motilities based on the unique classes of movement-producing protein architectures. Based on this criterion, the current total of independent motility systems stands at 18 types. In this perspective, we discuss these modes of motility relative to the latest phylogenetic Tree of Life and propose a history of motility. During the ~4 billion years since the emergence of life, motility arose in Bacteria with flagella and pili, and in Archaea with archaella. Newer modes of motility became possible in Eukarya with changes to the cell envelope. Presence or absence of a peptidoglycan layer, the acquisition of robust membrane dynamics, the enlargement of cells and environmental opportunities likely provided the context for the (co)evolution of novel types of motility

    Preventive effects of betamethasone valerate ointment for radiation-induced severe oral mucositis in patients with oral or oropharyngeal cancer: protocol for a multicentre, phase II, randomised controlled trial (Bet-ROM study)

    Get PDF
    Introduction: This is a randomised, multi-centre, open-label, phase II study to evaluate the efficacy of betamethasone valerate ointment on radiation-induced oral mucositis in patients with head and neck cancer undergoing concomitant radiotherapy with cisplatin or cetuximab.Methods and analysis: The trial will take place at seven hospitals in Japan. Patients will be randomised (1:1) into betamethasone and control groups after the occurrence of grade 1 oral mucositis. In the betamethasone group, patients will use betamethasone valerate ointment five times a day, in addition to usual oral hygiene guidance. The primary endpoint is the incidence and onset time of grade 3 oral mucositis. The secondary endpoints are the incidence and onset time of grade 2 oral mucositis, incidence and onset time of oral candidiasis, completion of radiation therapy and adverse events. Target accrual is 102 patients with a two-sided type I error rate of 5% and 80% power to detect an 80% risk reduction in the incidence of grade 3 oral mucositis.Ethics and dissemination: This study was approved by the Clinical Research Review Board of Nagasaki University (No. CRB20-009). All participants will be required to provide written informed consent. Findings will be disseminated through scientific and professional conferences and peer-reviewed journal publication. The datasets generated during the study will be available from the corresponding author on reasonable request.Trial registration number: jRCTs071200013

    A hydroxypropyl methylcellulose plaque assay for human respiratory syncytial virus

    Get PDF
    ウイルスの研究において感染性のあるウイルス粒子を正確に定量することは,病原性の評価のみならずウイルスに対する新規治療薬の効果を客観的に評価するために極めて重要な手技である.プラークアッセイ法はウイルス粒子を定量するために不可欠な技術であるが,Respiratory syncytial virus(RSV)において,プラークアッセイ法を安定して行うことはしばしば困難である.今回我々は,overlay material(充填化合物)が細胞増殖に与える影響を中心にRSVおよびhuman metapneumovirus(hMPV)におけるプラークアッセイ法の最適化の検討を行った

    Optical Study of the Stripe-Ordered State

    Full text link
    The effects of the stripe order on the optical spectra of La-based cuprates are reviewed. The main effect on the high Tc superconducting cuprates is to rapidly reduce the Josephson plasma frequency in the c-axis spectrum as a consequence of weakening of the Josephson coupling between CuO2 layers. This points toward a two dimensional (2D) superconductivity in the stripe phase, although it is difficult to realize a 2D superconductivity in real materials. We also discuss the experimental results suggesting the presence of stripe effect in other cuprates even if they do not show the static stripe phase. Compared to the c-axis spectra, the in-plane spectra are not so dramatically affected by the stripe order, showing a weak gap-like feature and reducing the condensate spectral weight.Comment: in press, Physica C(2012

    Conduction-band electronic states of YbInCu4 studied by photoemission and soft x-ray absorption spectroscopies

    Get PDF
    We have studied conduction-band (CB) electronic states of a typical valence-transition compound YbInCu4 by means of temperature-dependent hard x-ray photoemission spectroscopy (HX-PES) of the Cu 2p3/2 and In 3d5/2 core states taken at hν=5.95 keV, soft x-ray absorption spectroscopy (XAS) of the Cu 2p3/2 core absorption region around hν∼935 eV, and soft x-ray photoemission spectroscopy (SX-PES) of the valence band at the Cu 2p3/2 absorption edge of hν=933.0 eV. With decreasing temperature below the valence transition at TV=42 K, we have found that (1) the Cu 2p3/2 and In 3d5/2 peaks in the HX-PES spectra exhibit the energy shift toward the lower binding-energy side by ∼40 and ∼30 meV, respectively, (2) an energy position of the Cu 2p3/2 main absorption peak in the XAS spectrum is shifted toward higher photon-energy side by ∼100 meV, with an appearance of a shoulder structure below the Cu 2p3/2 main absorption peak, and (3) an intensity of the Cu L3VV Auger spectrum is abruptly enhanced. These experimental results suggest that the Fermi level of the CB-derived density of states is shifted toward the lower binding-energy side. We have described the valence transition in YbInCu4 in terms of the charge transfer from the CB to Yb 4f states
    corecore