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  • Artikel: DFG Deutsche Nationallizenzen  (30)
  • 2000-2004  (10)
  • 1995-1999  (20)
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  • Artikel: DFG Deutsche Nationallizenzen  (30)
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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 4566-4571 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The extreme ultraviolet radiation emitted from a plasma generated by a pulsed Nd:yttrium aluminum garnet laser is investigated around 13 nm wavelength for several low Z elements (lithium, nitrogen, oxygen, fluorine). A narrowband EUV source can be designed by using the narrowband line emission of low Z elements in combination with the broadband reflection characteristic of silicon/molybdenum (Si/Mo) multilayer mirrors. Experimental results are discussed within a theoretical model, which allows a deduction of an optimization criterion for a maximum conversion efficiency. The Lyman-α line of hydrogenlike lithium ions fulfills the demands for high intense, free-standing narrowband emission at the long wavelength side of the silicon absorption L edge. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 4180-4184 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The microscopic structure and the spatial distribution of the cathode spots in a radial multichannel pseudospark switch have been investigated by means of scanning electron microscopy. Current pulses of about 15 μs duration and peak amplitudes up to 340 kA have been applied. When using stainless steel and copper as electrode material cathode spots of type I and type II are observed. These cathode spots appear in groups (macrospots) with a diameter of several 100 μm. Assuming that the lifetime of the macrospots corresponds to the half period time of the current pulse the distribution of the cathode spots within the macrospots can be explained by a retrograde motion of the spots with a velocity of several 100 m/s in the self-magnetic field of the discharge current. Furthermore, the spatial distribution of the cathode spots within the macrospots can be interpreted by assuming a splitting and a repulsion of the cathode spots. The electrode phenomena show that the discharge current is distributed over a large area which is prerequisite for low erosion and long lifetime operation of the switch. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 1936-1938 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The electron emission from a field emission trigger unit was matched to the requirements for the simultaneous ignition of all channels in a radial multichannel pseudospark switch for a large parameter range of the pseudospark discharge. In such trigger unit the electrons are extracted from the surface of a high-ε material by field emission after applying a pulsed voltage. Electron emission occurs in a pressure range from 1–50 Pa, where the pseudospark discharge is operated. The access to low working gas pressures (〈10 Pa) using such trigger unit allows for achieving high hold-off voltages. The ignition of the pseudospark discharge was investigated by means of high speed photography and by a parallel observation of the electron beam of a single discharge channel, which occurs in hollow-cathode phase. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 7068-7072 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Highly efficient population transfer between the (0,0,0) and the (9,1,0) vibrational levels of the electronic ground state X˜ 1A1 of SO2 is demonstrated. The process relies on stimulated Raman scattering with adiabatic passage induced by two suitably delayed ultraviolet laser pulses with nearly transform-limited bandwidth. A transfer efficiency of 100% is achieved. The associated dark resonance is observed. Properties of the latter are compared for delayed and fully overlapping pulses. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 534-546 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: We demonstrate and analyze a novel scheme for complete transfer of atomic or molecular population between two bound states, by means of Stark-chirped rapid adiabatic passage (SCRAP). In this two-laser technique a delayed-pulse laser-induced Stark shift sweeps the transition frequency between two coupled states twice through resonance with the frequency of the population-transferring coupling laser. The delay of the Stark-shifting pulse with respect to the pulse of the coupling-laser Rabi frequency guarantees adiabatic passage of population at one of the two resonances while the evolution is diabatic at the other. The SCRAP method can give a population-transfer efficiency approaching unity. We discuss the general requirements on the intensity and timing of the pulses that produce the Rabi frequency and, independently, the Stark shift. We particularly stress extension to a double-SCRAP technique, a coherent variant of stimulated emission pumping in the limit of strong saturation. We demonstrate the success of the SCRAP method with experiments in metastable helium, where a two-photon transition provides the Rabi frequency. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science, Ltd
    Clinical & experimental allergy 32 (2002), S. 0 
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background The results of numerous studies on the influence of breastfeeding in the prevention of atopic disorders are often contradictory. One of the most important problems is confounding by other lifestyle factors.Objective The aim of the present study was to analyse the effect of any breastfeeding duration on the prevalence of atopic eczema in the first seven years of life taking into account other risk factors.Methods In an observational birth cohort study 1314 infants born in 1990 were followed-up for seven years. At 3, 6, 12, 18, 24 months and every year thereafter, parents were interviewed and filled in questionnaires, children were examined and blood was taken for in vitro allergy tests. Generalized Estimation Equations (GEE)-models were used to model risk factors for the prevalence of atopic eczema and for confounder adjustmentResults Breastfeeding was carried out for longer if at least one parent had eczema, the mother was older, did not smoke in pregnancy, and the family had a high social status. The prevalence of atopic eczema in the first seven years increased with each year of age (OR 1.05; 95% CI 1.01–1.09 for each year), with each additional month of breastfeeding (1.03; 1.00–1.06 for each additional month), with a history of parental atopic eczema (2.06; 1.38–3.08), and if other atopic signs and symptoms appeared, especially specific sensitization (1.53; 1.25–1.88), and asthma (1.41; 1.07–1.85). Although breastfeeding should be recommended for all infants, it does not prevent eczema in children with a genetic risk.Conclusion Parental eczema is the major risk factor for eczema. But in this study, each month of breastfeeding also increased the risk
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford BSL : Blackwell Science Ltd
    Clinical & experimental allergy 30 (2000), S. 0 
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Allergic diseases are more prevalent in affluent countries, which has been attributed to life-style factors. Life-style habits may also differ between socioeconomic (SES) classes. The objective of this paper therefore was to evaluate if SES had an impact on the development of atopic disorders.〈section xml:id="abs1-2"〉〈title type="main"〉MethodsA total of 1314 German children were followed-up in an observational birth cohort study to 6 years of age. Parents filled in questionnaires, and had multi-allergen screening tests for sensitization. Indoor allergen concentrations were determined by ELISA. Children were examined regularly up to 6 years, specific serum IgE values were determined by CAP-Rast-Feia.〈section xml:id="abs1-3"〉〈title type="main"〉ResultsThe risk of aeroallergen sensitization (odds ratio 1.76; 95% CI 1.30–2.37), and the lifetime prevalence of hay fever (2.36; 1.76–3.17), and asthma (1.74; 1.08–2.80), but not of atopic dermatitis (AD: 0.90; 0.54–1.51) was elevated in parents of high compared to low SES. With high SES the risk of smoking in pregnancy (0.35; 0.23–0.51), in the home (0.31; 0.21–0.46), pet ownership (0.37; 0.26–0.55), high mite (0.42; 0.25–0.74), and high cat (0.38; 0.18–0.82) allergen concentration in house dust was reduced, but elevated for breastfeeding over more than 6 months (4.67; 2.9–7.48). In children, even after controlling for other risk factors, only the risk of AD from 3 to 6 years (2.42; 1.42–4.14) was elevated in families with high SES, but not of AD in infancy or of any other atopic disorder.〈section xml:id="abs1-4"〉〈title type="main"〉ConclusionsWhile parents of high SES have a higher prevalence of inhalative allergies, their favourable life-style prevents the development of atopic disorders in their children, except for AD beyond infancy.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 27 (1997), S. 0 
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background Atopic family history and cord blood IgE have been used as predictors of atopic disease in newborns for about 20 years, but at least for cord blood IgE the sensitivity has been shown to be very low. The objective of this paper was to evaluate whether parental history and cord blood-IgE were more accurate predictors for the appropriate atopic phenotypes in the infants rather than for any atopy.Methods A total of 1314 newborn infants was recruited in six German obstetric departments in 1990 and followed-up for 2 years. Four hundred and ninty-ninc (38%) were at high risk for atopy with at least two first degree atopic family members and/or elevated cord-blood IgE concentrations.Results The cumulative incidence of atopic dermatitis over the first 2 years of life (AD24) amounted to 20. 1%, and there was a significant association with AD history of the mother (OR 2.5, 95%-Cl 1.46–4.26) and of the father (OR 3.53, 95%cC1 1.90–6.54). The cumulative incidence of recurrent wheezing in the first 2 years of life (RW24) amounted to 16.1%, and was positively associated with asthma history (OR 2.11, 95%CI 1.33–3.60) and sensitization history (OR 1.64, 95%C1 1.34–2.36) of the mother, but with neither for the father. RW24 was less prevalent in girls than in boys (OR 0.64. 95%Cl 0.47–0.89). Thirty-one per cent of infants were sensitized (CAP test value 〉 0.35 kU/L) against at least one of nine food or inhalative allergens (S24) and this was signilicantly associatcd with cord blood-IgE value (OR 2.43, 95%C1 1.69–3.49). and sensitization history of the mother (OR 1.64, 95%CI 1.18–2.41). Using multiple logistic regression analysis, the prediction of AD24 by AD of parents, of RW24 by asthma of parents, and of sensitization by cord blood IgE was of low accuracy.Conclusion The predictive capacity of parental history and cord blood IgE is not high enough to recommend them as screening instruments for primary prevention. The majority of atopic manifestations and of sensitization occur in infants with no demonstrable risk at birth.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 52 (1997), S. 0 
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: For screening atopy risk in 6401 (84%) of all infants born during the year 1990 in six obstetric departments of five German cities, cord-blood IgE values were determined with CAP-RAST-FEIA. After cases with elevated IgA values had been excluded, 25 % of the values were above the detection limit of 0.35 kU/1, and 8.5% were above 0.9 kU/1. Boys had significantly higher values than girls (P≤0.001). The distribution of values was significantly different for different nationalities of mothers (P≤0.001). The percentage of elevated values (≥0.9kU/l) increased significantly with the number of close family members with atopic history (P≤0.001). Regarding the atopic history of the father, siblings, and mother separately, only the mother's history had a significant association with the cord-blood IgE class (P≤0.001). The IgE values of 81 twin pairs correlated significantly with a coefficient of r = 0.4909 (P≤0.001). The smoking history of the parents during pregnancy showed an association with cord-blood IgE values (P≤0.02). No significant association could be shown between cord-blood IgE distribution and other variables, i.e., gestational age, birth size, birth modus, Apgar score, cord-blood pH value, neonatal problems, parity, age of the mother, medication during pregnancy, educational level of mother or father, time of year, or obstetric department. It is hypothesized that, in addition to some postpartum contamination or placental transfer of maternal IgE, cord-blood IgE values are also determined by the fetal immunologic reaction to intrauterine exposure to allergens and trigger factors, and by genetic influences.
    Materialart: Digitale Medien
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