1,194 research outputs found

    R-mode oscillations and rocket effect in rotating superfluid neutron stars. I. Formalism

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    We derive the hydrodynamical equations of r-mode oscillations in neutron stars in presence of a novel damping mechanism related to particle number changing processes. The change in the number densities of the various species leads to new dissipative terms in the equations which are responsible of the {\it rocket effect}. We employ a two-fluid model, with one fluid consisting of the charged components, while the second fluid consists of superfluid neutrons. We consider two different kind of r-mode oscillations, one associated with comoving displacements, and the second one associated with countermoving, out of phase, displacements.Comment: 10 page

    Annual direct and indirect costs attributable to nocturia in Germany, Sweden, and the UK

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    OBJECTIVE: Our aim was to estimate the prevalence-based cost of illness imposed by nocturia (≥2 nocturnal voids per night) in Germany, Sweden, and the UK in an average year. METHODS: Information obtained from a systematic review of published literature and clinicians was used to construct an algorithm depicting the management of nocturia in these three countries. This enabled an estimation of (1) annual levels of healthcare resource use, (2) annual cost of healthcare resource use, and (3) annual societal cost arising from presenteeism and absenteeism attributable to nocturia in each country. RESULTS: In an average year, there are an estimated 12.5, 1.2, and 8.6 million patients ≥20 years of age with nocturia in Germany, Sweden, and the UK, respectively. In an average year in each country, respectively, these patients were estimated to have 13.8, 1.4, and 10.0 million visits to a family practitioner or specialist, ~91,000, 9000, and 63,000 hospital admissions attributable to nocturia and 216,000, 19,000, and 130,000 subjects were estimated to incur a fracture resulting from nocturia. The annual direct cost of healthcare resource use attributable to managing nocturia was estimated to be approximately €2.32 billion in Germany, 5.11 billion kr (€0.54 billion) in Sweden, and £1.35 billion (€1.77 billion) in the UK. The annual indirect societal cost arising from both presenteeism and absenteeism was estimated to be approximately €20.76 billion in Germany and 19.65 billion kr (€2.10 billion) in Sweden. In addition, in the UK, the annual indirect cost due to absenteeism was an estimated £4.32 billion (€5.64 billion). CONCLUSIONS: Nocturia appears to impose a substantial socioeconomic burden in all three countries. Clinical and economic benefits could accrue from an increased awareness of the impact that nocturia imposes on patients, health services, and society as a whole

    In vivo absorption spectroscopy of tumor sensitizers with femtosecond white light

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    A system based on a femtosecond white-light continuum and a streak camera was used for recordings of the in vivo absorption spectra of the tumor-seeking agent disulphonated aluminum phthalocyanine. Measurements for different drug doses were performed on tumor tissue (muscle-implanted adenocarcinoma) and normal muscle tissue in rats. It was found that the shape of the spectrum is tissue dependent. The peak of the absorption spectrum is blueshifted in tumor tissue as compared with the muscle. Thus the contrast in the drug-related absorption can be altered by up to a factor of 2 from the primary drug molecular-concentration contrast between normal muscle and tumor by the proper selection of the illumination wavelength

    Compact medical fluorosensor for minimally invasive tissue characterization

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    A compact fiber-optic point-measuring fluorosensor fully adapted to clinical studies is described. The system can use two excitation wavelengths, 337 and 405 nm, obtained from a nitrogen laser directly, or after dye laser conversion, respectively. The image intensifier used in the spectrometer can be gated with a variable time delay, allowing also time-resolved spectra to be extracted, with a time resolution of about 4 ns. Moreover, diffusely scattered white light can be spectrally recorded. The system is fully computer controlled enabling short recording times in clinical application, which are illustrated

    Concentration measurement of gas embedded in scattering media by employing absorption and time-resolved laser spectroscopy

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    Diode-laser-based absorption spectroscopy for the evaluation of embedded gas concentrations in porous materials is demonstrated in measurements of molecular oxygen dispersed throughout scattering polystyrene foam, used here as a generic test material. The mean path length of light scattered in the material is determined with the temporal characteristics of the radiation transmitted through the sample. This combined with sensitive gas-absorption measurements employing wavelength-modulation spectroscopy yields an oxygen concentration in polystyrene foam of 20.4% corresponding to a foam porosity of 98%, which is consistent with manufacturing specifications. This feasibility study opens many possibilities for quantitative measurements by using the method of gas-in-scattering-media absorption spectroscopy. (C) 2002 Optical Society of America

    2'-O-(2-methoxyethyl) nucleosides are not phosphorylated or incorporated into the genome of Human Lymphoblastoid TK6 Cells

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    Nucleoside analogues with 2'-modified sugar moieties are often used to improve the RNA target affinity and nuclease resistance of therapeutic oligonucleotides in preclinical and clinical development. Despite their enhanced nuclease resistance, oligonucleotides could slowly degrade releasing nucleoside analogues that have the potential to become phosphorylated and incorporated into cellular DNA and RNA. For the first time, the phosphorylation and DNA and RNA incorporation of 2'-O-(2-methoxyethyl) (2'-O-MOE) nucleoside analogues have been investigated. Using LC/MS/MS, we showed that enzymes in the nucleotide salvage pathway including deoxycytidine kinase (dCK) and thymidine kinase (TK1) displayed poor reactivity toward 2'-O-MOE nucleoside analogues. On the other hand, 2'-fluoro (F) nucleosides, regardless of the nucleobase, were efficiently phosphorylated to their monophosphate forms by dCK and TK1. Consistent with their efficient phosphorylation by dCK and TK1, 2'-F nucleosides analogues were incorporated into cellular DNA and RNA while no incorporation was detected with 2'-O-MOE nucleoside analogues. In conclusion, these data suggest that the inability of dCK and TK1 to create the monophosphates of 2'-O-MOE nucleoside analogues reduces the risk of their incorporation into cellular DNA and RNA

    Feasibility study of a system for combined light dosimetry and interstitial photodynamic treatment of massive tumors

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    A system for the photodynamic laser treatment of massive tumors that employs multiple optical fibers to be inserted into the tumor mass is described. The light flux through the tumor can be assessed by use of the individual fibers both as transmitters and as receivers. With a computer model that describes the diffusive light propagation, optical dosimetry is under development, The system has been tested in an experimental animal tumor model in preparation for clinical work. Currently, delta-aminolevulinic acid is used as a sensitizer, activated by 635-nm radiation from a 2.0-W compact diode laser system. With the availability of future, highly selective drugs absorbing approximately 750 nm, larger tumor volumes should be treatable, and surrounding, sensitive normal tissue should be spared
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