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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 46 (1968), S. 457-464 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Quartz is considered a chemically inert material. However, its respirable dusts are an occupational health problem. The initial step of the silicotic reaction is a cytotoxic effect on the phagocytes by the ingested SiO2-particles. All solid SiO2-modifications except stishovite proved to be cytotoxic. This cytotoxicity results in a high turnover of phagocytes, which seems to be — by a yet unknown mechanism — the stimulus for the formation of the fibrohyaline silicotic nodule. There is more information on the mechanisms involved in the cytotoxic action of SiO2-dusts. It can be explained by the damage of biological membranes. This is the consequence of an interaction of membrane lipids or lipoproteins with the SiO2 particle surface, which may be mainly an adsorption process. There have been many approaches to control this problem of occupational hygiene, e.g. devices to diminish dust generation or inhalation, attempts to stimulate the physiological elimination of dusts from the respiratory tract or to inhibit connective tissue proliferation. More recently, polyvinylpyridine-N-oxide found bySchlipköter andBrockhaus proved to be a protecting agent that inhibits all biological reactions of silicogenic dustsin vitro andin vivo. Whether this substance itself can be used for therapy may be an open question. However, it demonstrates a principal possibility to influence specifically the silicotic reaction.
    Notes: Zusammenfassung Obgleich Quarz zu den chemisch besonders inerten Stoffen gehört, wird er in Form von Feinstäuben zu einer gewerblichen Noxe. Am Anfang der silikotischen Reaktion steht eine Schädigung der Phagocyten durch aufgenommene SiO2-Partikel. Sämtliche festen SiO2-Modifikationen mit Ausnahme des Stischowits erwiesen sich als cytotoxisch. Zelluntergänge und Rephagocytosen des freiwerdenden Staubes führen zu einem Zellverschleiß, an den sich schließlich die Bildung charakteristischer fibrohyaliner Knötchen anschließt. Die biochemischen und zellphysiologischen Vorgänge, die vom Zellverschleiß zur Fibrose und zur hyalinen Schwiele führen, sind noch nicht befriedigend geklärt. Dagegen können die intracellulären Vorgänge, die der Phagocytenschädigung zugrunde liegen, auf eine Membranschädigung zurückgeführt werden. Diese kommt durch Wechselwirkungen von Membranlipoiden bzw. Lipoproteiden mit der Oberfläche silikogener Stäube zustande, wobei wahrscheinlich Adsorptionen im Vordergrund stehen. Trotz technischer Schutzmaßnahmen blieb das gewerbehygienische Problem bestehen. Versuche, z. B. pharmakologisch die Staubelimination zu beeinflussen bzw. die Bindegewebsneubildung zu hemmen, erwiesen sich therapeutisch als unzureichend. Im Polyvinylpyridin-N-oxid wurde dann vonSchlipköter undBrockhaus eine Schutzsubstanz gefunden, die alle biologischen Reaktionenin vitro undin vivo hemmt. Auch bei vorsichtiger Beurteilung mit dieser Substanz selbst gegebener therapeutischer Möglichkeiten, ist damit doch ein Weg zur spezifischen Beeinflussung der Silikose sichtbar.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 14 (1978), S. 405-412 
    ISSN: 1432-1041
    Keywords: Colloidal plasma substitutes ; cross-linked polypeptides ; Haemaccel® ; pharmacokinetics ; renal failure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Infusions of 3.5% isocyanate cross-linked polypeptide solution 500 ml were given to 52 patients with normal or impaired renal function: glomerular filtration rate (GFR)=0–133 ml/min. The serum concentration and urinary excretion of hydroxyproline were measured and the equivalent polypeptide concentrations were calculated from the results. In patients with normal renal function (GFR〉90 ml/min) the proportion of polypeptide excreted in the urine up to 12 h was 45.4±2.6% ( $$\bar X$$ ±SEM), up to 24 h 47.7±2.9% and up to 48 h 49.3±3.4%. In patients with moderate renal insufficiency (GFR=30–90 ml/min) there was no decrease in polypeptide excretion and even in patients with more serious impairment of GFR (11–30 ml/min) 48-h urinary polypeptide excretion was still 40.6±5.9%. In patients with GFR of 2–10 ml/min polypeptide excretion fell to 10.7±3.2% during the first 12 h, although there was an increase in later collection periods as compared to patients with normal renal function −19.9±3.9% in 24 h and 27.0±3.5% in 48 h. The elimination half-life (t1/2) calculated from serum concentrations was 505±30 min ( $$\bar X$$ ±SEM) in patients with normal renal function (GFR〉90 ml/min). Only when the GFR fell below 30 ml/min did it slowly begin to increase. In patients with minimal residual renal function (GFR=0–0.5 ml/min), who were on haemodialysis, the elimination half-life was 985±49 min, i.e. approximately twice the normal. Twice weekly infusion of 3.5% polypeptide solution 500 ml over a period of 6 weeks did not produce any significant cumulation in haemodialysis patients (GFR=0–0.5 ml/min). A weekly dose of polypeptide 35 g appeared to be quite safe when given for several weeks, even to anuric patients. As no significant amount of polypeptide was lost during haemodialysis, the dose can be chosen without taking into account any effect of intermittent haemodialysis.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Clinica Chimica Acta 18 (1967), S. 267-273 
    ISSN: 0009-8981
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Electroanalytical Chemistry 99 (1979), S. 321-330 
    ISSN: 0368-1874
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experiments and analytical methods for determining electron-ion recombination and attachment coefficients in highly collisional, cylindrically symmetric plasmas are presented. Photoionization by sparkboard light sources of tetrakisdimethylaminoethylene (TMAE) seeded in atmospheric-pressure helium is used to produce the plasma. The electron density is probed by microwave transmission techniques. The effective recombination coefficient for electrons recombining with TMAE ions in atmospheric pressure helium is found to be (9.0±1.1)×10−6 cm3 s−1 for Te=300 K.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 1290-1296 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Comparisons between experimentally measured time-dependent electron energy distribution functions and optical emission intensities are reported for low-frequency (100 and 400 kHz) radio-frequency driven discharges in argon. The electron energy distribution functions were measured with a time-resolved Langmuir probe system. Time-resolved optical emissions of argon resonance lines at 687.1 and 750.4 nm were determined by photon-counting methods. Known ground-state and metastable-state excitation cross sections were used along with the measured electron energy distribution functions to calculate the time dependence of the optical emission intensity. It was found that a calculation using only the ground-state cross sections gave the best agreement with the time dependence of the measured optical emission. Time-dependent electron density, electron temperature, and plasma potential measurements are also reported.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 207 (1965), S. 874-875 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Since haemolysis is a simple model for the damage of the membranes of cells and sub-cellular particles, several mineral dusts which had been checked previously for fibrogenic effects in animal experiments3'4 were tested for their haemolytic activities. Six different modifications of silica were ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 5341-5348 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Properties of reduced density channels created by energy deposition from electron beams propagating in air are presented. A multi-beam laser deflection technique used to diagnose the channels is described, as are representative examples of density channels formed in multi-pulse propagation experiments performed at the Advanced Test Accelerator at the Lawrence Livermore National Laboratory.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 5089-5094 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Strong microwave absorption was observed when a 10 GHz source illuminated an underdense collisional plasma that had a density gradient scale length several wavelengths long. Significant reductions in angular scattering and cross-polarized components were also observed. These experiments confirm that absorption was the dominant process. The plasma was created by the photoionization of tetrakisdimethylaminoethylene molecules seeded into atmospheric pressure helium. Sparkboard arrays provided the intense vacuum ultraviolet ionizing radiation. Plasma density profiles were measured using transverse scans of 9.7 GHz probe microwaves and were found to approximate an Epstein profile. The absorption at 10 GHz by this plasma was as large as 28 dB in direct backscattering and 15–20 dB when orthogonally polarized microwaves were launched and detected. The peak absorption scales with sparkboard energy in a way that suggests that electron-ion recombination is the dominant electron-loss mechanism at high plasma densities.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 6187-6190 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Plasma-deposited thin films of polycrystalline diamond were achieved with an arcjet plasma. The jet operated with hydrogen gas with small admixtures of CH4. The diamond films were highly nonuniform, probably due to the very high gradients of the chemical species and temperatures within the arcjet-substrate system. The arcjet apparatus, and optical emission spectra and Langmuir probe diagnostics of the plasma are described. Also presented are results for the surface chemical analysis of the diamond film using surface analysis by laser ionization.
    Type of Medium: Electronic Resource
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