234 research outputs found

    Analysis of modal evolution caused by a weakly range-dependent seabed in shallow water and its application to inversion for geoacoustic properties

    Get PDF
    Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1993In a shallow water ocean environment, the range-dependent variation of the geoacoustic properties of the seabed is one of the crucial factors affecting sound propagation. Since the local modes of propagation depend on the spatial changes in the bottom sediments, the local eigenvalues of these modes are useful as tools for examining the range dependence of the sediment properties. In order to extract the local eigenvalues from measurements of the pressure field in a laterally inhomogeneous waveguide, the zero-order asymptotic Hankel transform with a short sliding window is utilized. The local peak positions in the output spectra differ from the local eigenvalues due to both the range variation of the local modes and the interference of adjacent modes. The departure due to the former factor is evaluated analytically by using the stationary phase method. In order to reduce the error induced by the latter factor, mode filtering is utilized by incorporating data from a fixed vertical array of receivers. The use of the above zero-order Hankel transform in a three-dimensionally varying waveguide results in an underestimate of the local eigenvalues due to the effect of horizontal refraction. Thus a general asymptotic Hankel transform with a 2-D sliding window is used to correct for the underestimated amount. By expanding the latter transform with respect to the azimuthal angle, it can also be shown that the first term in the Taylor series corresponds to the former transform; the rest of the terms account for the value difference between the underestimated and actual local eigenvalues. In order to obtain the spatial variation of the sediment properties from the rangedependent variation of the extracted local eigenvalues, the analytical relationship between these two variations is derived by using a perturbation method in a horizontally varying, multi-layered bottom model. Upon use of the n2-linear profile in each layer, the relationship can be obtained in closed form. As a result, the range variation of the local eigenvalues may be separated into terms that depend on each geoacoustic parameter. Based on this relation, an inversion method for determining the range-dependent geoacoustic parameters is developed. The methods developed in this thesis are applied to simulated pressure field data as well as experimental field data. It is shown that the evolution with range of the local modes as well as the range-dependent geoacoustic properties can be successfully estimated.Financial support for my research was provided by the WHOI Education Department and the Office of Naval Research

    Modification of Cɛ mRNA Expression by EBV-Encoded Latent Membrane Protein 1

    Get PDF
    To evaluate the effect of expression of latent membrane protein (LMP) 1 encoded by Epstein-Barr virus (EBV) on Cɛ mRNA expression, mRNA levels were examined by RT-PCR or Northern blot analysis upon transient transfection of LMP1 in the splenocytes derived from Brown-Norway rats with or without immunization with 2,4-dinitrophenyl-conjugated Ascaris suum antigen. Splenocytes were transfected with LMP1 expression vector, pSG5-LMP1, using lipofection method. Cɛ mRNA levels were considerably increased by transfection with pSG5-LMP1 in the splenocytes derived from the nonimmunized rats; however, Cɛ mRNA levels were decreased in the splenocytes derived from the immunized rats. Cɛ mRNA expression in IgE-producing cells are modulated by LMP1, which might depend on the differentiation status of B cells upon exposure to allergen

    Periostin in Allergic Inflammation

    Get PDF
    ABSTRACTPeriostin, an extracellular matrix protein belonging to the fasciclin family, has been shown to play a critical role in the process of remodeling during tissue/organ development or repair. Periostin functions as a matricellular protein in cell activation by binding to their receptors on cell surface, thereby exerting its biological activities. After we found that periostin is a downstream molecule of interleukin (IL)-4 and IL-13, signature cytokines of type 2 immune responses, we showed that periostin is a component of subepithelial fibrosis in bronchial asthma, the first formal proof that periostin is involved in allergic inflammation. Subsequently, a great deal of evidence has accumulated demonstrating the significance of periostin in allergic inflammation. It is of note that in skin tissues, periostin is critical for amplification and persistence of allergic inflammation by communicating between fibroblasts and keratinocytes. Furthermore, periostin has been applied to development of novel diagnostics or therapeutic agents for allergic diseases. Serum periostin can reflect local production of periostin in inflamed lesions induced by Th2-type immune responses and also can predict the efficacy of Th2 antagonists against bronchial asthma. Blocking the interaction between periostin and its receptor, αv integrin, or down-regulating the periostin expression shows improvement of periostin-induced inflammation in mouse models or in in vitro systems. It is hoped that diagnostics or therapeutic agents targeting periostin will be of practical use in the near future

    Synthesis of carbon nanotubes by microwave heating: Influence of diameter of catalytic Ni nanoparticles on diameter of CNTs

    Get PDF
    We rapidly synthesized multi walled carbon nanotubes (MWCNTs) by calcination of granulated polystyrene with nickel nanoparticles having different average diameter (D-Ni = 10, 20, 50 or 90 nm) under nitrogen gas at a certain temperature and time (700 degrees C, 15 min or 800 degrees C, 10 min), using a domestic microwave oven in order to systematically investigate the influence of the diameter of nickel nanoparticles on the diameter of MWCNTs. The MWCNTs synthesized here were characterized by a transmission electron microscope, a Raman spectrophotometer and a wide angle X-ray diffractometer. We found that for the calcination condition of (800 degrees C, 10 min), a relationship between the outer diameter of the resulted carbon nanotubes (D-CNT) and the diameter of catalytic nickel nanoparticles (D-Ni) can be described as a linear function, D-CNT = 1.01D(Ni) + 14.79 nm with the correlation coefficient R = 0.99, and that for the calcination condition of 700 degrees C, 15 min, D-CNT = 1.12D(Ni) + 7.80 nm with R = 0.95. Thus, we revealed that when the diameter of the catalytic nickel nanoparticles (D-Ni) increases by 1 nm, the outer diameter of the obtained MWCNTs (D-CNT) increases by about 1 nm.ArticleJOURNAL OF MATERIALS CHEMISTRY A. 2(8):2773-2780 (2014)journal articl

    Prevalence and Intra-Family Phylogenetic Divergence of Burkholderiaceae-Related Endobacteria Associated with Species of Mortierella.

    Get PDF
    Endofungal bacteria are widespread within the phylum Mucoromycota, and these include Burkholderiaceae-related endobacteria (BRE). However. the prevalence of BRE in Mortierellomycotinan fungi and their phylogenetic divergence remain unclear. Therefore, we examined the prevalence of BRE in diverse species of Mortierella. We surveyed 238 isolates of Mortierella spp. mainly obtained in Japan that were phylogenetically classified into 59 species. BRE were found in 53 isolates consisting of 22 species of Mortierella. Among them, 20 species of Mortierella were newly reported as the fungal hosts of BRE. BRE in a Glomeribacter-illycoavidus Glade in the family Burkholderiaceae were separated phylogenetically into three groups. These groups consisted of a group containing Mycoavidus cysteinexigens, which is known to be associated with M. elongata, and two other newly distinguishable groups. Our results demonstrated that BRE were harbored by many species of Mortierella and those that associated with isolates of Mortierella spp. were more phylogenetically divergent than previously reported

    Brazilian Propolis Suppresses Angiogenesis by Inducing Apoptosis in Tube-Forming Endothelial Cells through Inactivation of Survival Signal ERK1/2

    Get PDF
    We recently reported that propolis suppresses tumor-induced angiogenesis through tube formation inhibition and apoptosis induction in endothelial cells. However, molecular mechanisms underlying such angiogenesis suppression by propolis have not been fully elucidated. The aim of this study was to investigate the effects of ethanol extract of Brazilian propolis (EEBP) on two major survival signals, extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt, and to elucidate whether changes in these signals were actually involved in antiangiogenic effects of the propolis. Detection by western blotting revealed that EEBP suppressed phosphorylation of ERK1/2, but not that of Akt. Pharmacological inhibition by U0126 demonstrated that ERK1/2 inactivation alone was enough to inhibit tube formation and induce apoptosis. It was also shown that EEBP and U0126 similarly induced activation of caspase-3 and cleavage of poly ADP-ribose polymerase (PARP) and lamin A/C, all of which are molecular markers of apoptosis. These results indicate that inhibition of survival signal ERK1/2, and subsequent induction of apoptosis, is a critical mechanism of angiogenesis suppression by EEBP

    APPLICATION OF OUTER SURFACE IRRADIATED LASER STRESS IMPROVEMENT PROCESS (L-SIP) TO PRESSURIZER AS RESIDUAL STRESS IMPROVEMENT METHOD FOR ALLOY 600 PWSCC MITIGATION

    Get PDF
    ABSTRACT Improvement of residual stress is effective in a countermeasure to deal with the stress corrosion cracks in pipe welds. A irradiated laser stress improvement process (L-SIP) will be introduced as a method to improve residual stress inside steel pipes. This work method is to improve inner surface residual stress from tensile stress to compressive stress by irradiating laser beam around the welds of steel pipe and utilizing the temperature differences between inner and outer surface. Recently this method is applied to PWR pressurizer surge nozzle on TRUGA unit 2. INTRODUCTION In the welds of steel pipes at nuclear power plant or thermal power plant, stress corrosion crack (SCC) is regarded as a damage mode. Stress corrosion crack is caused by tensile residual stress, materials and environment (including water quality and temperature, etc.). It is very difficult to improve the material and environment of pipes in operation plant. Therefore, the residual stress improvement work method is used as a simplified method. In order to improve residual stress, some ways of peening including shot peening are applied. In the welds of steel pipes, it is often impossible to apply them to inner surface of pipes where stress corrosion crack occurs due to the inaccessibility. To date, the use of laser beam as a maintenance technology for nuclear power plants have been studied (1)(2)(3)(4) , it is one of the applicable method from outside of the pipe. This study will report the first application to nuclear power plant in order to improve the inner residual stress of pressurizer surge nozzle

    A pet-type robot AIBO-assisted therapy as a day care program for chronic schizophrenia patients

    Get PDF
    BackgroundAAT (Animal-assisted therapy) was developed to promote human social and emotional functioning as a day care program for psychiatric patients.AimsIn this study, we performed AAT using a pet-type robot, AIBO for schizophrenic patients.Methods After obtaining informed consent, we performed the AIBO-assisted therapy for three schizophrenic (ICD-10, F20.x2) patients (male: 1, female: 2) whose medication did not change over the 8 weeks study period in a ward.Results It was found that the AAT using AIBO may be useful for the patients with negative and general psychopathological symptoms such as “Anxiety” and “Uncooperativeness”.ConclusionWe make use of this result, and we want to develop the AAT program using a pet-type robot, AIBO which may be suitable for Japanese psychiatric patients

    Nodal Merkel Cell Carcinoma in Head and Neck Lesions with an Unknown Primary: A Case Report in Light of the Literature

    Get PDF
    Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine skin cancer. To diagnose nodal MCC with an unknown primary disease is challenging, and it has to be separated from other nodal metastatic neoplasms. We report a unique case of nodal MCC in head and neck lesions with an unknown primary. A 70-year-old woman was admitted to our department with a right submandibular mass. Fine needle aspiration biopsy was performed and indicated malignancy. F-18-fluorodeoxyglucose positron emission tomography (PET) demonstrated abnormal accumulation in the right submandibular lymph node, right palatine tonsil, and right thyroid gland. For diagnostics and treatment, bilateral selective neck lymph node dissection, right tonsillectomy, and right thyroidectomy were performed. Histopathological examination revealed that most parts of the submandibular lymph node were occupied by diffuse sheets of tumor cells. Contrary to our expectation, malignant cells were not detected in the right palatine tonsil and right thyroid. Immunohistochemistry demonstrated a marked positive reaction for AE1/AE3, chromogranin A, synaptophysin, cytokeratin 20 (CK20) and CD56 and a negative reaction for vimentin, leucocyte common antigen (LCA), thyroid transcription factor-1 (TTF1) and cytokeratin 7 (CK7) in the tumor cells. Immunostaining of Merkel cell polyomavirus-large T antigen (MCPyV-LT) showed a positive reaction and MCPyV-positive MCCs were assessed by PCR analysis, demonstrating that viral copy number was 12.8 copies per cell. These histological findings confirmed the diagnosis of Merkel cell carcinoma of the lymph node. In cases of tumors in the lymph node with a neuroendocrine appearance in head and neck lesions, it is necessary to eliminate the possibility of metastasis from MCC
    corecore