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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 4295-4297 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Position sensors are a key technology for controlled actuation systems, which are required to meet increasingly exacting dynamic performance specifications. Of the various sensing technologies, variable differential transformers are capable of satisfying stringent performance criteria, in terms of resolution, repeatability, and stability of output, while operating in the harshest of environments. They utilize the variation of mutual inductance which occurs between a primary and two secondary coils as a ferromagnetic core is moved by the object whose position is to be measured. The article is concerned with rotary variable differential transformers, which currently use high permeability magnetic alloys, such as nickel–iron, either solid or laminated. However, since they are being required to operate at increased excitation frequencies, up to 5 kHz, there is interest in the use of powder composite magnetic materials, which, although having a lower permeability, have a higher electrical resistivity, and hence reduced eddy current effects. The potential for such materials is investigated by steady-state ac finite element analysis, and shown to be promising. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental dermatology 13 (1988), S. 0 
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Forty-two patients with mycologically proven onychomycosis involving 48 nails were treated topically with a paste formulation of 1% bifonazole and 40% urea following one of two treatment regimens. The results using the most effective regimen (Regimen 2), which involved daily application of the medication for 1 week, produced a mycological cure rate of 62–5% at 12 weeks, reduced to 46% at follow-up at 24 weeks. These results compare favourably with those obtained by long-term systemic treatment with griseofulvin. Such topical treatment ought to be considered as an alternative in onychomycosis especially that of the toenails.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental dermatology 12 (1987), S. 0 
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Tinea capitis is a common childhood infection that has recently become more frequent in urban areas in Europe and the U.S.A. The current licensed treatment in children is griseofulvin 10 mg kg−1 daily, which is usually given for 6–8 weeks. Objectives To compare this treatment with a 4-week course of oral terbinafine. Methods Terbinafine was given at the following doses: in children weighing 〈 20 kg, 62·5 mg daily; 20–40 kg, 125 mg daily; 〉 40 kg, 250 mg daily. Two hundred and ten children aged 2–16 years, with mycologically confirmed tinea capitis, were randomized to 4 weeks treatment with terbinafine or 8 weeks with griseofulvin, and followed for a total of 24 weeks to determine the difference between treatments with respect to short- and long-term efficacy and tolerability. Results One hundred and forty-seven patients were evaluable (terbinafine 77, griseofulvin 70). Although the 4-week course of terbinafine resulted in a trend to more rapid clearance of tinea capitis, there were no statistically significant differences between the two drugs in terms of overall outcome or tolerability, apart from in a subgroup of patients with Trichophyton infections, and weighing 〉 20 kg, who responded better to terbinafine than to griseofulvin at 4 weeks. By contrast, there was a better response to griseofulvin than to terbinafine in patients with Microsporum audouinii infections. Conclusions Overall, the study showed that 4 weeks of treatment with oral terbinafine has similar efficacy to 8 weeks of treatment with griseofulvin for the management of tinea capitis in children.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 135 (1996), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Recent observations on tinea capitis cases in London suggest that there has been a change in the pattern of infection with a recent and significant rise in the incidence of Infections due to anthropophilic fungi. The purpose of this study was to investigate the prevalence and Identity of tinea capitis in schools in south-east London and factors which might affect the spread of infection. This was achieved by carrying out a survey of all children, with parental consent for scalp examination, in 14 nursery, infant or junior schools in Lambeth. In addition, the accuracy of clinical diagnosis was compared with mycological findings. There were 1057 children from 4 to 14 years of age in the study. The infection rate in different schools ranged from 0 to 12% with a mean of 2.5%. A further 4.9% of children were scalp carriers of dermatophytes (range in classes 0–47%). A striking feature was that all infections were caused by anthropophilic fungi, mainly Trichophyton tonsurans or Microsporum rivalieri, and there was a correlation between the presence of two or more carriers within a class and the infection in the other children. There was a poor correlation between ability of trained observers to predict infection on clinical grounds and mycological results. This investigation shows variable but significant levels of scalp ringworm in schools and that the dominant organisms are anthropophilic. It provides support for the observation that there has been a shift in the pattern of tinea capitis in London and. possibly, other U.K. centres, with a trend towards more infections transmissible among children, with T. tonsurans being the commonest organism. The implications for control, which involve screening in schools, where appropriate, and guidance to general practitioners on treatment, are discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 120 (1989), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The effects on 31 normal subjects following exposure to sunbeds containing UVA lamps with minimal UVB emission have been compared in a double-blind study with the effects on nine control subjects of a similar exposure course three times weekly for 4 weeks to sunbeds emitting visible light. On previously untanned areas, all those subjects on active treatment developed a mild tan; in tanned areas they all developed a moderate tan, while all control subjects developed a minimal to mild tan. The mean protection factor against later UVB-induced erythema was 3.2±0.3 after the active course and 1.6±0.2 among the controls. Significantlsy more frequent adverse cutaneous effects for active subjects were pruritus, erythema, freckling, burning sensation, dryness and polymorphic light eruption. Cutaneous Langerhans cell numbers, and blood CD3+ (pan T-cell) and CD4+ (helper T-cell) lymphocyte subsets were reduced in both active and control groups. CD8+ (cytotoxic/suppressor T-cell) counts were significantly reduced in both groups. The changes found in both groups seem attributable to small amounts of UVB emission from both active and control lamps.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of the European Academy of Dermatology and Venereology 15 (2001), S. 0 
    ISSN: 1468-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A survey of tinea capitis conducted under the auspices of the European Confederation of Medical Mycology showed that laboratories contributing to a voluntary scheme for reporting have recently been seeing a different pattern of scalp ringworm. The survey was conducted among 92 medical mycology laboratories across 19 European countries by postal questionnaire comparing the years 1987 with 1997. The survey shows an overall increase in the numbers of cases caused by anthropophilic infections, which, in 1997, were the dominant causes of scalp infection; the greatest increase was seen in laboratories covering urban populations and in African Caribbean children living in Europe. While the commonest infection remains Microsporum canis, the largest overall increase has been in Trichophyton tonsurans, which in 1997 was the second commonest cause of infection overall and the commonest in urban populations. The pattern of change is not uniform in Europe and while some cities have reported large increases in T. tonsurans others, e.g. in France, have seen more cases of infection due to T. soudanense and M. audouinii. While these figures do not necessarily reflect changes in the underlying prevalence of infection, the trends are important to recognize as the control measures for anthropophilic tinea capitis differ from those used in zoophilic infections. In particular there is a need for an increased level of surveillance and more advice on control given to primary care physicians, dermatologists and school health authorities.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: The performance of fifth generation offspring of a desert annual (Dimorphotheca sinuata DC.) were compared in the absence of UV-B, under variable atmospheric CO2 and nutrient supply, after four consecutive generations of concurrent exposure of their progenitors to UV-B at ambient (seasonal range: 2.55–8.85 kJ m–2 d–1) and enhanced (seasonal range: 4.70–11.41 kJ m–2 d–1) levels. Offspring of progenitors grown under elevated UV-B exhibited a diminished photosynthetic rate, a consequence of a reduced leaf density, and diminished foliar levels of carotenoids, polyphenolics and anthocyanins. Conversely, nonstructural carbohydrate and chlorophyll b levels were increased. Altered physiology was accompanied by reduced apical dominance and earlier flowering, features generally considered under photomorphogenic control, increased branching and inflorescence production and greater partitioning of biomass to reproductive structures, but diminished seed production. Many of these changes were magnified under nutrient limitation and intensified under atmospheric CO2 enriched conditions. The latter disagrees with current opinion that elevated CO2 may reduce detrimental UV-B effects, at least over the long-term. Observed correlations between seed production and polyphenolic, especially anthocyanin, levels in offspring, and indications of diminished lignification (thinner leaves, less robust stems and fewer lignified seeds set) all pointed to the involvement of the phenylpropanoid pathway in seed formation and plant structural development and its disruption during long-term UV-B exposure. Comparisons with earlier generations revealed trends with cumulative generations of enhanced UV-B exposure of increasing chlorophyll b and nonstructural carbohydrates, decreasing polyphenolics and biomass allocation to vegetative structures, and diminishing seed production despite increasing biomass allocation to reproductive structures. Notwithstanding some physiological compensation (increased chlorophyll b), the accumulation and persistence of these ostensibly inherited changes in physiological and reproductive performance suggest a greater impact of elevated UV-B on vegetation, primary production and regeneration over the long-term than presently envisaged.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Global change biology 9 (2003), S. 0 
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: The distribution and abundance of trees can be strongly affected by disturbance such as fire. In mixed tree/grass ecosystems, recurrent grass-fuelled fires can strongly suppress tree saplings and therefore control tree dominance. We propose that changes in atmospheric [CO2] could influence tree cover in such metastable ecosystems by altering their postburn recovery rates relative to flammable herbaceous growth forms such as grasses. Slow sapling recovery rates at low [CO2] would favour the spread of grasses and a reduction of tree cover. To test the possible importance of [CO2]/fire interactions, we first used a Dynamic Global Vegetation Model (DGVM) to simulate biomass in grassy ecosystems in South Africa with and without fire. The results indicate that fire has a major effect under higher rainfall conditions suggesting an important role for fire/[CO2] interactions. We then used a demographic model of the effects of fire on mesic savanna trees to test the importance of grass/tree differences in postburn recovery rates. We adjusted grass and tree growth in the model according to the DGVM output of net primary production at different [CO2] relative to current conditions. The simulations predicted elimination of trees at [CO2] typical of the last glacial period (180 ppm) because tree growth rate is too slow (15 years) to grow to a fire-proof size of ca. 3 m. Simulated grass growth would produce an adequate fuel load for a burn in only 2 years. Simulations of preindustrial [CO2] (270 ppm) predict occurrence of trees but at low densities. The greatest increase in trees occurs from preindustrial to current [CO2] (360 ppm). The simulations are consistent with palaeo-records which indicate that trees disappeared from sites that are currently savannas in South Africa in the last glacial. Savanna trees reappeared in the Holocene. There has also been a large increase in trees over the last 50–100 years. We suggest that slow tree recovery after fire, rather than differential photosynthetic efficiencies in C3 and C4 plants, might have been the significant factor in the Late Tertiary spread of flammable grasslands under low [CO2] because open, high light environments would have been a prerequisite for the spread of C4 grasses. Our simulations suggest further that low [CO2] could have been a significant factor in the reduction of trees during glacial times, because of their slower regrowth after disturbance, with fire favouring the spread of grasses.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Populations of the desert annual Dimorphotheca sinuata, derived from a common seed stock, were exposed concurrently over four successive generations to either ambient (representing no stratospheric ozone depletion) or elevated (representing 20% stratospheric ozone depletion) UV-B levels during their complete life cycle. Leaf fluctuating asymmetry (FA) was measured in populations of plants grown from seeds of selected generations which had experienced different UV-B exposure histories, and from seeds collected from a wild population of this species which grows in a naturally enhanced UV-B environment. These measured plants had been grown in a greenhouse under essentially UV-B-free conditions. Leaf FA was significantly increased by greater numbers of enhanced UV-B exposures in the parentage of the seed. There was a linear to exponential dose–response relationship between number of UV-B exposure iterations in seed parentage and leaf FA, suggesting that damage to DNA caused by UV-B exposure during plant development may not be fully repaired, and thus be inherited by offspring and accumulated over successive generations in this species. Leaf FA of plants grown from seed from the wild population was not significantly greater than that of control plants whose parentage experienced only ambient UV-B exposures, although this negative result may have been due to low sampling intensity and measurement resolution, and the relatively low UV-B enhancement experienced by the wild population. We conclude that leaf FA may constitute a relatively sensitive yet inexpensive means of quantifying UV-B damage to plants.
    Type of Medium: Electronic Resource
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