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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Der Hautarzt 49 (1998), S. 10-16 
    ISSN: 1432-1173
    Schlagwort(e): Schlüsselwörter UV-Schutzfaktor ; Kleidung ; Sonnenschutz ; Prävention ; Key words Fabrics ; Clothes ; Sun protection ; Prevention ; Skin cancer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary A rising incidence worldwide of skin cancer has been observed for years. A high cumulative exposure to UV radiation is a major factor in the development of such neoplasms. Suitable protective measures are therefore becoming increasingly important. Textiles provide simple, effective and medically safe protection against UV radiation. At present, however, in Europe – in contrat to Australia – the UV protection factor (UPF) for summer textiles is not stated. It is a largely unknown fact that by far not all textiles offer sufficient protection. Our goal was to study the factors which determine the UV transmission of fabrics and, based on these findings, to design materials which provide enhanced protection. A spectrophotometric method was used to determine the UV transmission by fabrics made of cotton, silk, polyester and viscose. The UV protection factors of the fabrics were computed on the basis of the transmission data. The UV protection factor is dependent on the type of fibre, yarn and surface design, weight per square metre, moisture content, colour, finishing method and degree of wear. To optimize the UV protection via textiles, a viscose yarn with a low UV transmission was used. This yarn makes it possible to design light-weight summer fabrics with optimized UV protection. This development will make it possible to offer clothing with high UV protection on the European marked. This clothing will not be more expensive than normal products, so that effective prevention should be more available.
    Notizen: Zusammenfassung Seit Jahren wird ein weltweiter Anstieg der Hautkrebsinzidenz beobachtet. Eine hohe kumulative UV-Strahlenexposition gilt als ein Hauptfaktor für die Entstehung von Neoplasien der Haut. Geeignete Schutzmaßnahmen gewinnen daher zunehmend an Bedeutung. Textilien bieten eine einfachen und effektiven, medizinisch unbedenklichen Schutz vor der UV-Strahlung, doch wird der UV-Schutzfaktor (USF) von Sommertextilien, z.Z. in Europa – im Gegensatz zu Australien – nicht angegeben.Weitgehend unbekannt ist in diesem Zusammenhang, daß bei weitem nicht alle Textilien einen ausreichenden Schutz bieten. Ziel ist, die Faktoren, welche die UV-Durchlässigkeit von Stoffen bestimmen, zu untersuchen und ausgehend von diesen Ergebnissen Materialien mit verbessertem Schutz zu konstruieren. Die UV-Durchlässigkeit wurde an Geweben aus Baumwolle, Seide, Polyester und Viskose mit einer spektralphotometrischen Methode bestimmt. Die UV-Schutzfaktoren der Stoffe wurden aus den Transmissionsdaten berechnet. Anhand der Ergebnisse konnte gezeigt werden, daß UV-Schutzfaktor von der Faserart, der Garn- und Flächenkonstruktion, dem Quadratmetergewicht, dem Feuchtegehalt, der Färbung, der Ausrüstung und der Abnutzung durch den Gebrauch der Stoffe abhängt. Zur Optimierung des UV-Schutzes durch Stoffe wurde erstmals ein Viskosegarn mit einer extrem geringen UV-Durchlässigkeit eingesetzt. Dieses Garn ermöglicht es, leichte Sommerstoffe mit optimiertem UV-Schutz zu konstruieren. Zukünftig wird es damit möglich sein, Kleidung mit einem hohen UV-Schutzfaktor anzubieten. Diese Kleidung wird nicht teurer sein als normale Produkte, so daß eine hohe Effektivität für unsere Präventionsbemühungen erwartet werden kann.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Tissue cultures and regenerant plants from cell lines producing palms with normal and abnormal flowers were analyzed for cytokinin content and compared with zygotic embryos and seedlings. Immature inflorescences at the critical stage of flower development dissected from normal and abnormal palms were also analyzed. High performance liquid chromatography (HPLC)/radioimmunoassay and HPLC/enzyme-linked immunosorbent assay methods were used over a period of several years to measure the isoprenoid cytokinins. The results of analyses of endogenous aromatic cytokinins, present at comparable levels, will be reported separately. Oil palm cultures and regenerant plants contained relatively high concentrations of the 9-glucosides of isopentenyladenine ([9G]iP) and zeatin ([9G]Z). The predominant biologically active isoprenoid cytokinin present was zeatin riboside ([9R]Z), with lesser amounts of isopentenyladenine (iP) and isopentenyladenosine ([9R]iP). There was evidence of small amounts of dihydrozeatin compounds, but high concentrations (mainly as dihydrozeatin-9-glucoside ([9G]DHZ)) were confined to the haustorium of the zygotic embryo. Callus tissue contained very low concentrations of cytokinin. Frequently only [9G]iP could be detected, at about 1 pmol · g-1 fresh weight, with [9R]Z at less than 0.05 pmol · g-1. In comparison, nodular embryogenic tissues in vitro contained between 30 and 1,500 pmol · g-1 of [9G]iP, 5–50 pmol · g-1 of [9G]Z, and up to 12 pmol · g-1 of [9R]Z. Shoots of regenerant plantlets and seedlings contained lower concentrations of [9G]iP (3–30 pmol · g-1), although this was still the predominant cytokinin. [9R]Z and [9G]Z were present at between 2 and 15 pmol · g-1, with iP at 1–5 pmol · g-1 and [9R]iP at between 1 and 12 pmol · g-1. Seedlings contained similar amounts with the exception of a lower [9G]iP content (5–10 pmol · g-1) and more [9R]iP (10–20 pmol · g-1). Root tissues of ramets contained significantly higher concentrations of [9G]iP than shoots. Comparison of two isogenic lines of one clone giving rise to normal and abnormal palms showed significantly higher concentrations of [9R]Z and [9G]Z in the normal than in the abnormal line and, in embryoids only, higher [9G]iP in the normal line. In all other cases the between-done differences were greater than any normal/abnormal differences. There was a general tendency for increased concentrations of [9G]iP in abnormal lines and for this compound to be in a higher concentration in embryoids and plants derived from culture than in zygotic embryos and seedlings. Analysis of cytokinins in immature female inflorescences of normal and abnormal palms of a single clone showed the abnormal inflorescences to have higher concentrations of [9R]Z and [9R]DHZ and less [9G]Z than the normal inflorescences at comparable stages of development.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 15 (1996), S. 39-49 
    ISSN: 1435-8107
    Schlagwort(e): Oil palm ; Cytokinin ; Topolin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The natural occurrence of 6-benzylaminopurine, 6-(2-hydroxybenzylamino)purine (ortho-topolin), 6-(3-hydroxybenzylamino)purine (meta-topolin), their ribosides and 9-glucosides is reported using specific antibodies to these groups of compounds in high performance liquid chromatography/enzyme-linked immunosorbent assay (HPLC/ELISA). Compounds were identified by their retention times and differential cross-reactivities with six antisera in analyses carried out in two laboratories using different HPLC gradient systems. Identities were confirmed by immunoaffinity purification followed by HPLC with on-line UV spectrum analysis. Further confirmation of the occurrence of ortho-topolin riboside and isopentenyladenine-9-glucoside was obtained from gas chromatography-mass spectrometry analysis of permethylated HPLC fractions of an extract of oil palm tissues. The aromatic cytokinins, and in particular, ortho-topolin riboside, were found in a variety of oil palm tissues at concentrations exceeding those of the isoprenoid cytokinins, zeatin, isopentenyladenine, dihydrozeatin, and their ribosides. The 9-glucosides of isopentenyladenine and zeatin were more abundant than those of the aromatic types. The cross-reactivity of benzyladenine compounds with antibodies to isopentenyladosine is discussed in relation to the interpretation of ELISA data.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 15 (1996), S. 95-102 
    ISSN: 1435-8107
    Schlagwort(e): Cell cycle ; Cytokinin ; Soybean cells ; Glycine max ; Immunocytochemistry ; S phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract An immunocytochemical method was used to determine the proportion of cells in the DNA synthesis (S phase) of the mitotic cycle in suspension cultures of soybean (Glycine max (L.) Merr. cv. Acme) callus of cotyledonary origin, the stably cytokinin-dependent tissue used in the cytokinin bioassay devised by Carlos O. Miller. A standard cell synchronization protocol involving hydroxyurea was used to demonstrate the applicability of the immunocytochemical method to this cell culture. Cells were brought to mitotic arrest by cytokinin withdrawal, and the cell division cycle was restarted by the addition of cytokinin. We have followed the pattern of resumption of S phase after the readdition of cytokinin. This pattern reveals the existence of three subpopulations of cells in cytokinin-starved cultures, consistent with the occurrence of three cytokinin-requiring events in the cell cycle: one in mitosis, one in S phase, and one in the G1 phase.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 16 (1997), S. 89-93 
    ISSN: 1435-8107
    Schlagwort(e): Key Words.Glycine max—Polyamines—Phenolic compounds—l-AOPP—Cell division—Cell elongation—Cytokinin starvation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract. Effects on growth, mostly of an inhibitory nature, have been attributed to phenolic compounds in vivo and in vitro. This suggests that l-α-aminooxy-β-phenylpropionic acid (l-AOPP), a competitive inhibitor of phenylalanine ammonia-lyase (PAL), the enzyme controlling the first step in phenylpropanoid synthesis, might stimulate growth in soybean suspension cultures (Glycine max, cv. Acme). The promotive effect of l-AOPP, measured as an increase in cell number, was more clearly detected in the growth-limiting condition of cytokinin starvation. At least one more cell division cycle was completed in the presence of l-AOPP before growth by division ceased and growth continued by expansion only. Phenolic acids are known to conjugate with polyamines, modulating the free levels of these plant growth substances. Thus, the effect of l-AOPP on the titers of free and conjugated polyamines (putrescine, spermidine, and spermine) was investigated by high performance liquid chromatography in the course of cytokinin starvation. An increased level of free putrescine was detected in the presence of l-AOPP relative to controls, especially in the initial period before growth became restricted to cell expansion. The decrease in free putrescine associated with the cessation of cell division was temporarily delayed, suggesting that an interaction between phenolic acids and polyamines is involved in the mechanism of growth promotion by l-AOPP.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    ISSN: 1573-3297
    Schlagwort(e): Acoustic startle response ; habituation ; sensitization ; fear ; genetic differences
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract An increase in general responsiveness after aversive stimulation has provided a most widely accepted and well-understood sensitization paradigm. According to a second paradigm (based on the dual process theory of habituation and sensitization), not only additional aversive stimuli, but also the response-eliciting stimuli themselves, induce sensitization. To relate these two sensitization paradigms, we compared the course of startle response parameters during repetitive acoustic stimulation with the change in startle amplitude after electric footshocks in outbred Wistar and Sprague–Dawley rats. Compared to the Wistar rats used, the Sprague–Dawley rats showed a lower response decrement and a shortened latency during repetitive stimulation, both of which are indicators of increased sensitization by the startle-eliciting stimuli. In addition, the Sprague–Dawley rats also demonstrated a reduced increase in startle amplitude following footshock. This was postulated to be a consequence of the strong sensitization by startle-eliciting stimuli, which interferes with sensitization elicited by footshock. Because our Wistar and Sprague–Dawley rats did not differ in initial startle amplitude, but mainly in susceptibility to sensitization, further comparisons of these genetically different stocks of rats seem to be of potential value in studying differences in fear-motivated behavior.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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