bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation on foaming of EAF slags in the production of stainless steel
Authors: Vidacak B. , Arvanitidis I. , Jönsson P. G. , Sjöberg P.
Published: March 2003

This study focused on slag‐foaming phenomena, the main emphasis being on slags used in the electric arc furnace (EAF) practice in the manufacture of stainless steel. Plant trials were carried out at Sandvik Steel for slags of high and low chromium content. The viscosity of the slags was predicted using a mathematical model for multi‐component slags developed at KTH, Stockholm. Next, the foaming characteristics were predicted using different relationships suggested in the literature. The predicted foaming behavior was then compared to estimations of foaming determined visually and acoustically by operators. Sound measurements were also carried out during the trials. In comparing foaming characteristics determined from sound measurements with the operator estimations, a relationship was found to exist between the two.
Improvement in the surface quality of ball bearing steel rounds at Bar Mill
Authors: Topno Roylen , Gupta D. S. , Singh U. P. , Roy B. , Jha S.
Published: March 2003

The rejection of ball bearing steel rounds had increased at Bar Mill due to surface defects following an increase in the demand for a better surface quality. The genesis of surface defects in ball bearing steel rounds is attributed to steel‐making and rolling processes. The steel‐making defects are exogenous in nature with the presence of non‐metallic inclusions in steel. The rolling defects are generated due to poor quality of the input billets, improper thermal regime of reheating, incorrect setting of entry and exit guides, misaligned roll pass line and inappropriate rolling schedule. This paper discusses the generation of surface defects and the formulation of a strategy to reduce these defects at Bar Mill. The improvement in the surface condition of the input billets, correct entry/exit guide setting and modification in roll pass design have reduced the rejection rate by 34.6%.
Hybrid modelling of the rolling force in a plate mill
Authors: Wiklund Olof , Korhonen Risto , Nilsson Annika , Sidestam Patrik
Published: March 2003

Different empirical and hybrid modelling techniques were evaluated in order to improve the modelling compared with the present situation in the plate rolling mill at Rautaruukki, Raahe. Logged data from the production were used to develop new models and to compare them with each other and with the present model. The data describe the chemical composition and various process parameters of the rolling process, including thermal, geometric and kinematic parameters. Various neural networks and multivariate models were evaluated in order to take non‐linear effects into account. Hybrid methods use a combination of physically based models and empirical models. The simple physically based formula, force = area x yield strength factor, proved useful. A more advanced model solving von Karman's differential equation was evaluated as a stand‐alone model and as part of a hybrid model. The measured force of the previous rolling pass was tested as an additional input variable. Various aspects of the different modelling techniques are discussed and compared. Simple but improved models are described as suitable candidates to replace the present on‐line model.
Investigation of the kinetics of ferrous oxide reduction in the slurries of metallurgical processes
Authors: Paunova R. , Todorov K. , Damgaliev D.
Published: March 2003

The present paper is devoted to investigations of the reduction kinetics of ferrous oxides contained in the slurry mixtures of metallurgical products at the Kremikovtzi‐AD firm. The mixtures are selected to permit pellets and agglomerates to be obtained which are suitable for blast furnace pig iron production. As a reducing agent in the laboratory investigations, a small fraction of coke with 88% carbon is used. The experimental results are recorded within the temperature range 293–1183 K. The kinetic curves can be described by the following function:

where α is the degree of reduction (%), x is the temperature (K), and b0–b6 are model coefficients. The degree of ferrous oxide reduction is found (α = 43.14%) for a mixture containing 40% converter slurry, 40% blast furnace slurry and 8% electric steelmaking slurry The highest degree of reduction (α = 46.88%) is possessed by ferrous oxides in the mixtures containing 68% converter slurry and 22% blast furnace slurry. When the kinetic dependencies of industrial slurries are compared with those of synthetic slurries, they are seen to be very similar. This should be taken into account when choosing an effective technology for utilizing the slurry.
Optimization of corrosion resistance and mechanical properties on quenched and tempered rebar
Authors: Lundberg Sven‐Erik
Published: March 2003

Quenching and tempering of rebar is a process whereby a surface layer of tempered martensite is created on a ferritic‐pearlitic core. The tempering temperature determines the tensile properties, but quenching reduces the corrosion resistance. To optimize the corrosion resistance and find suitable steel compositions, experiments were carried out, using a two‐level experimental method for relevant control parameters, combined with cooling to different tempering temperatures from 940 to 560°C. Low tempering temperatures improve the corrosion resistance. The tensile properties can be described by equations derived from the experiments.
Divergent life histories among populations of the fish Brachyrhaphis rhabdophora: detecting putative agents of selection by candidate model analysis
Authors: Johnson Jerald B.
Published: March 2003

Studies of natural selection in the wild almost always begin by examining patterns of association between phenotypic adaptations and environmental factors thought to shape evolutionary change. Unfortunately, many studies pay little attention to the effects of model selection on the evolutionary inferences drawn from such correlative data. In this study, I employed a candidate model analysis to examine four potential causes of life‐history evolution in the livebearing fish Brachyrhaphis rhabdophora. Combining factor analysis with path analysis, I constructed a nested set of 17 models that represent the hypothetical effects of four putative selective agents (mortality, density, resource availability, and habitat stability) on life‐history evolution in this species. These models represent both direct and indirect effects of selection on the life history. Using the Akaike Information Criterion to distinguish among models, I found that simple models that contained only single selective agents most parsimoniously explained life‐history divergence among 27 B. rhabdophora populations. Surprisingly, the four putative selective agents could not be distinguished, suggesting that the selective environment could be composed of a single selective agent confounded with other environmental factors, or could be composed of a suite of environmental factors that act in concert to shape the life history. In addition, comparisons among more complex models indicated that direct effects of selective agents appear to have primacy over combinations of indirect selective interactions in explaining intraspecific variation in B. rhabdophora life histories.
Relationship between soil microarthropod species diversity and plant growth does not change when the system is disturbed
Authors: Liiri Mira , Setälä Heikki , Haimi Jari , Pennanen Taina , Fritze Hannu
Published: March 2003

Soil microarthropods influence vital ecosystem processes, such as decomposition and nutrient mineralisation. There is evidence, however, that proper functioning of ecosystems does not require the presence of all its constituent species, and therefore some species can be regarded as functionally redundant. It has been proposed that species redundancy can act as an insurance against unfavourable conditions, and that functionally redundant species may become important when a system has faced a disturbance (the “insurance hypothesis”).  We conducted a laboratory microcosm experiment with coniferous forest soil and a seedling of silver birch (Betula pendula). A gradient of microarthropod diversity (from one to tens of species of soil mites and Collembola) was created to the systems. We disturbed microcosms with drought to test whether systems with altering microarthropod species richness respond differently to perturbations. Primary production (birch biomass), uptake of nitrogen by the birch seedling, the system's ability to retain nutrients and the structure and biomass of the soil microbial community were analysed.  Primary production and nutrient uptake of the birch seedlings increased slightly with increasing microarthropod species richness but only at the species poor end of the diversity gradient. Loss of nutrients and the biomass and community structure of microbes were unaffected by the microarthropods. The effect of drought on the birch biomass production was independent of the species richness of microarthropods. During the disturbance the biomass of microarthropods declined in diverse systems but not in simple ones. These systems were, however, quite resilient; microarthropod communities recovered quickly after the disturbance. Our results suggest that soil microarthropod species are functionally redundant in respect to plant growth, and that the resistance of a system to and its recovery from a disturbance are only weakly related to the species richness of this fauna.
Intraspecific competition of endophyte infected vs uninfected plants of two woodland grass species
Authors: Brem Dominik , Leuchtmann Adrian
Published: March 2003

Grass endophytes (Clavicipitaceae, Ascomycota) are generally considered to be mutualists which increase the host's fitness. Infected plants are often more persistent and competitive than uninfected plants, influencing population dynamics and plant community diversity. However, most of this empirical evidence is based on studies focusing on agronomically important grass species such as tall fescue or perennial ryegrass and their implications for livestock and man‐made habitats. Recent studies indicate that endophyte‐plant associations may be more variable, ranging from parasitic to mutualistic. In the present study, we investigated the influence of endophyte infection on two wild woodland grasses, which are naturally infected with distinct fungal endophytes: Brachypodium sylvaticum with Epichloë sylvatica and Bromus benekenii with Epichloë bromicola. An intraspecific competition experiment was conducted over two growing seasons in the greenhouse and in an experimental garden. At first harvest (after 12 weeks growing), endophyte infection had a significant negative effect on above ground dry matter yield (DMY) of B. sylvaticum, but a significant positive effect on DMY of Br. benekenii under competition. The same differential effects on DMY and on total seed number were also observed at final harvest (after 62 weeks growing). Results from Br. benekenii were consistent with our hypothesis of increased competitive abilities of infected plants in nature which could explain the high infection rate observed in natural populations. In contrast, this explanation does not hold true for B. sylvaticum, and other factors such as increased herbivore and pathogen resistance together with frequent horizontal transmission may be responsible for the very high incidence of this association in nature. Our results confirm previous predictions that beneficial effects of endophyte infection in wild grasses can vary for different grass species, even in comparable habitats.
Direct and indirect effects of masting on rodent populations and tree seed survival
Authors: Schnurr Jaclyn L. , Ostfeld Richard S. , Canham Charles D.
Published: March 2003

Many plant species are thought to benefit from mast seeding as a result of increased seed survival through predator satiation. However, in communities with many different masting species, lack of synchrony in seed production among species may decrease seed survival by maintaining seed predator populations through the intermast cycle. Similarly, masting by different plant species may have different effects on the seed predator community. We conducted a three‐year study in a northeastern USA temperate deciduous forest to determine if production of large seed crops by several tree species was synchronous, and if they had similar effects on all small mammal species. We found that red oak mast crops resulted in increased densities ofPeromyscus leucopusandP. maniculatus, but had no effect onClethrionomys gapperiabundance. Conversely,C. gapperipopulations, but notPeromyscuspopulations, appeared to increase in response to a large red maple seed crop. Differences in small mammal abundance resulted in changes in species‐specific seed survival: in the year of abundantC. gapperi, experimentally placed red oak acorns had significantly higher survival than in the year of highPeromyscusabundance. Red oak acorn removal was positively correlated withPeromyscusabundance, while red maple seed removal was significantly higher with increasedC. gapperiabundance. Thus, species‐specific seed production had differential effects on subsequent small mammal abundance, which in turn affected seed survival. We suggest that at the level of the community, even short‐term lack of synchrony in production of large seed crops can cause variation in postdispersal seed survival, through differential effects on the community of small mammal seed predators.
Pollen limitation, seed predation and scape length in Primula farinosa
Authors: Ehrlén Johan , Käck Sofia , Ågren Jon
Published: March 2003

Floral display and reward production may affect the attractiveness of a plant to a range of interacting animals including pollinators, herbivores, and vectors of pathogenic fungi. The optimal floral phenotype should therefore depend on the relative importance of selection exerted by both mutualistic and antagonistic animals. The perennial, rosette herb Primula farinosa is polymorphic for scape length. Natural populations may include both plants with flowers displayed well above the ground (the long‐scaped morph) and those with flowers positioned very close to the ground (the short‐scaped morph). In this study, we conducted a field experiment to examine how the relative fitness of the two scape morphs is affected by interactions with pollinators and fruit predators in two different microhabitats (high and low vegetation). As predicted based on the difference in floral display, supplemental hand‐pollination showed that fruit initiation was more strongly pollen‐limited in the short‐scaped than in the long‐scaped morph, and that this difference was significantly larger in high than in low vegetation. Moreover, plants with a short scape experienced lower levels of fruit predation than plants with a long scape. Among open‐pollinated controls, there was no significant difference in seed output between the two scape morphs. However, among plants receiving supplemental hand‐pollination, short‐scaped plants produced significantly more seeds than long‐scaped plants. The results suggest that the positive and negative effects of a prominent floral display (increased pollination and seed predation, respectively) balance in the study population, but also that the short‐scaped morph would have an advantage at higher pollination intensities. Spatial and temporal variation in pollinator activity and seed predation should result in associated variation in the relative fecundity of the two scape morphs.
Variability of intra‐ and interspecific competitions of bamboo stump mosquito larvae over small and large spatial scales
Authors: Sunahara Toshihiko , Mogi Motoyoshi
Published: March 2003

We carried out field experiments to examine the variability of interspecific competition of mosquito larvae among microcosms in a bamboo grove (small spatial scale) and between bamboo groves at two sites, with single and multiple mosquito species (large spatial scale). Four types of microcosms that differed in capacity and litter input were set. In the hillside bamboo grove, where multiple species occurred, succession of the predominant species from Aedes albopictus to Tripteroides bambusa was observed in control microcosms from which no mosquito larvae were removed. Weekly removal of competitive species resulted in increased pupation of A. albopictus and adult body weight under both rich and poor resource conditions. In the late period of the experiments, the effect of competitor removal on pupation of A. albopictus was greater in deep containers that never dried than in shallow containers that were dried in the laboratory. The number of eggs showed a slight difference between competitor‐excluded and deep control microcosms. These results indicate that interspecific competition limits pupation of A. albopictus more strongly in deep containers than in shallow and drought‐prone containers.

 Compared with the hillside site, the larval density of A. albopictus attained a higher density in the bamboo grove in the plain where no competitive species occurred, due to a higher oviposition rate. Lower rate of pupation and lower adult weight at the plain site than at the hillside site indicated that resource limitation was more severe at the plain site. Populations of A. albopictus at hillside and plain sites appeared to suffer from strong inter‐ and intraspecific competition, respectively. At the hillside site, the intensity of interspecific competition appeared to increase later in the breeding season, with a high larval density of T. bambusa. In contrast, at the plain site, intensity of intraspecific competition appeared to be reduced later in the breeding season with decreasing larval density of A. albopictus.
Topsoil properties and seedling recruitment inLavandula latifolia: stage‐dependence and spatial decoupling of influential parameters
Authors: Herrera Carlos M.
Published: March 2003

This paper investigates the influence of topsoil texture and chemistry on long‐term patterns of seedling recruitment inLavandula latifolia(Labiatae), an evergreen Mediterranean shrub. The questions addressed are: (1) Are spatial patterns of seedling emergence and survival probabilities related to spatial variation in soil properties? (2) Are the two components of recruitment similarly influenced by the same soil parameters or, alternatively, are they influenced in different ways and/or by different soil parameters? (3) If the latter applies, then do the sets of soil parameters influencing emergence and survival show congruent patterns of spatial variation? Seed progenies from fourteen maternal families were sown at ten widely spaced field sites (between‐site distances in the scale of a few kilometers). Sites differed in average soil characteristics. There was also considerable variation in some soil parameters within sowing sites (distances between soil sampling points in the scale of meters). The seedling recruitment process was monitored for six years. Both the probability of one seed ofL. latifoliagiving rise to an emerged seedling, and the probability of an emerged seedling remaining alive six years past emergence and entering the juvenile age class, were significantly related to topsoil properties. Seedling emergence and survival tended to be influenced by largely non‐overlapping sets of soil properties that were related, respectively, to texture‐ and fertility‐related gradients. These two soil gradients tended to be uncorrelated at the scale of the study, and differed in the apportionment of variance among small (within sites) and large (between sites) spatial scales. While most variance in the emergence‐influencing, texture‐related gradient occurred at the between‐site scale, a considerably greater fraction of variance in the survival‐influencing, fertility‐related gradient occurred at the within‐site scale. It is suggested that, because of fine scale variability in soil fertility, local adaptations ofL. latifoliato soil textural properties enhancing seedling emergence will be easier to evolve than adaptations to fertility‐related features enhancing seedling survival.
Trade‐offs in host use by Manduca sexta: plant characters vs natural enemies
Authors: Mira Alex , Bernays Elizabeth A.
Published: March 2003

There are two principal native host plants for the sphingid moth Manduca sexta L. in south eastern Arizona: Datura wrightii (Solanaceae), and the more recently reported, nonsolanaceous host, Proboscidea parviflora (Martyniaceae). A comparative study on causes and rates of mortality was conducted, since this provided a “natural experiment” for examining potential trade‐offs in host use. The field data identified a dramatic trade‐off between plant quality and predation. D. wrightii appears to provide a high quality food source in growth experiments, and eggs laid on its leaves hatch at high rates. The eggs and larvae, however, underwent extremely high levels of predation and parasitism in the field, and fewer than 0.5% reached the final larval stage. Eggs laid on P. parviflora, on the other hand, suffered low levels of predation and virtually no parasitism, but many eggs did not hatch due to developmental abnormalities induced by the plant, while a large proportion of larvae died after a few days of feeding. Overall, 3% of the eggs reached the final stage on this plant. The maintenance of the two host plants cannot be explained by single factors, but rather by the outcome of multiple factors on the insect fitness, including plant quality, suitability for egg development, predation risk, plant availability and competition with other herbivores. Our data emphasize the importance of predation in shaping host‐plant ranges and support the idea of host‐specific predation rates and “enemy‐free” space.
Biodiversity and ecosystem productivity: implications for carbon storage
Authors: Catovsky Sebastian , Bradford Mark A. , Hector Andy
Published: March 2003

Recent experiments have found that Net Primary Productivity (NPP) can often be a positive saturating function of plant species and functional diversity. These findings raised the possibility that more diverse ecosystems might store more carbon as a result of increased photosynthetic inputs. However, carbon inputs will not only remain in plant biomass, but will be translocated to the soil via root exudation, fine root turnover, and litter fall. Thus, we must consider not just plant productivity (NPP), but also net productivity of the whole ecosystem (NEP), which itself measures net carbon storage. We currently know little about how plant diversity could influence soil processes that return carbon back to the atmosphere, such as heterotrophic respiration and decomposition of organic matter. Nevertheless, it is clear that any effects on such processes could make NPP a poor predictor of whole‐ecosystem productivity, and potentially the ability of the ecosystem to store carbon. We examine the range of mechanisms by which plant diversity could influence net ecosystem productivity, incorporating processes involved with carbon uptake (productivity), loss (autotrophic and heterotrophic respiration), and residence time within the system (decomposition rate). Understanding the relationship between plant diversity and ecosystem carbon dynamics must be made a research priority if we wish to provide information relevant to global carbon policy decisions. This goal is entirely feasible if we utilize some basic methods for measuring the major fluxes of carbon into and out of the ecosystem.
Effect of defoliation on grass growth. A quantitative review
Authors: Ferraro Diego O. , Oesterheld Martín
Published: March 2003

The diversity of responses of individual grasses to defoliation created a controversy about 15 years ago, which still needs clarification. We quantitatively assessed the evidence of defoliation effects on individual grass growth, addressing two main questions: 1) what is the average and variability of the effect of defoliation on plant growth? and 2) what are the associated conditions accounting for the diversity of effects? Regarding the first question, the results showed a negative overall effect of defoliation on plant growth and substantial variability in the defoliation responses of different plant components. There was an intermediate negative effect on total production (which included clipped‐off biomass), a large negative effect on final live biomass at harvest, and a minimal effect on root biomass. Regarding the second question (conditions accounting for the diversity of effects), defoliation intensity had no effect on the response to defoliation, but both time for recovery from the last defoliation and the period of time between defoliation events significantly decreased the negative effect of defoliation. Nitrogen availability also altered the effect of defoliation, as plants grown at highest nitrogen levels were more negatively affected by clipping than plants with no supplementary addition of nitrogen. These results indicate that the magnitude of defoliation response by an individual plant differs among plant compartments and this response is modulated by other factors, such as time for recovery after defoliation, and nutrient availability. In general, the effect of defoliation on individual plant production was more negative than reported effects of grazing on ecosystem primary production.
Disentangling the causes of damage variation by deer browsing on youngThuja plicata
Authors: Vourc'h Gwenaël , Vila Bruno , Gillon Dominique , Escarré José , Guibal Frédéric , Fritz Hervé , Clausen Thomas P. , Martin Jean‐Louis
Published: March 2003

Long‐lived trees experience different levels of damage due to mammalian herbivores. To untangle the mechanisms that underlie this variation, we combined chemical with dendrochronological analyses to study variation in browsing on Western redcedars (Thuja plicata) on Haida Gwaii (British Columbia, Canada). Since the last glaciation, Haida Gwaii forests had lacked large herbivore browser until Sitka black‐tailed deer (Odocoileus hemionus sitkensis) were introduced at the beginning of the 20th century. Dendrochronology yielded information on radial growth and plant annual responses to environmental stresses including herbivory. Secondary metabolite content and plant nutritional quality provided insights into proximate causes of food choices made by herbivores. We sampled lightly‐ and heavily‐browsed young trees at four sites: three clear‐cut sites with high browsing pressure and one old‐growth forest site where browsing pressure had, until recently, been lower. Heavily‐browsed young trees had lower concentrations of secondary metabolites and were of lower nutritive value than lightly‐browsed trees at all sites. Under high browsing pressure, tree growth patterns suggested that all young trees were initially severely browsed until some trees, currently scored as lightly‐browsed, started to escape deer. At the old‐growth site, both lightly‐ and heavily‐browsed trees tended to have lower overall average secondary metabolite concentrations than those of all other sites, a trend possibly related to greater canopy closure. Lightly‐browsed trees were older than heavily‐browsed ones which resulted, during the period of lower browsing pressure, in higher growth rate and a same pattern of change in growth from one year to the next year. This suggests that, under low browsing pressure, selection of young trees related to chemical defense was weak and that growth differences due to other factors than browsing could be expressed. Under strong browsing pressure, however, all young trees had equally low growth rates until trees with better genetic potential to produce effective defenses were able to escape deer. This suggests that selection by deer could occur on a long‐lived tree.
Feedbacks between canopy composition and seedling regeneration in mixed conifer broad‐leaved forests
Authors: Catovsky S. , Bazzaz F. A.
Published: March 2003

To address the role of canopy‐seedling feedbacks in the structure and dynamics of mixed conifer broad‐leaved forests in the eastern US, we monitored seedling regeneration patterns and environmental conditions in the understorey of stands dominated by either hemlock (Tsuga canadensis) or red oak (Quercus rubra) for three years. Hemlock seedlings were favoured over other species’ seedlings in hemlock stands (a true positive feedback), due to a combination of high seed inputs, high seedling emergence and relatively high seedling survival during the growing season, which allowed hemlock to remain dominant under its own canopy. Red oak stands favoured a suite of mid‐successional broad‐leaved species over hemlock. A more even age structure of broad‐leaved species in red oak stands revealed that high seedling survival in such stands were driving this feedback. Canopy‐mediated variations in both understorey light availability (1.5% for hemlock vs 3.5% for red oak) and soil pH (3.9 for hemlock vs 4.4 for red oak) were found to be the primary correlates of stand‐level differences in seedling regeneration dynamics. In mixed temperate forests in the eastern US, canopy‐seedling feedbacks could act to slow successional trajectories and contribute to the maintenance of a stable landscape structure over many generations.
Ultraviolet vision and foraging in terrestrial vertebrates
Authors: Honkavaara Johanna , Koivula Minna , Korpimäki Erkki , Siitari Heli , Viitala Jussi
Published: March 2003

Tetrachromatic colour vision, based on four ‘main’ colours and their combinations, is probably the original colour vision in terrestrial vertebrates. In addition to human visible waveband of light (400–700 nm) and three main colours, it also includes the near ultraviolet part of light spectrum (320–400 nm). The ecological importance of ultraviolet (UV) vision in animals has mainly been studied in the context of intra‐ and inter‐sexual signalling, but recently the importance of UV vision in foraging has received more attention. Foraging animals may use either UV cues (reflectance or absorbance) of food items or UV cues of the environment. So far, all diurnal birds studied (at least 35 species), some rodents (4 species), many reptilians (11 species) and amphibians (2 species) are likely able to see near UV light. This probably allows e.g. diurnal raptors as well as frugivorous, nectarivorous and insectivorous birds to use foraging cues invisible to humans. The possible role of UV cues and existing light conditions should be taken into account when food selection of vertebrate animals is studied, particularly, in experiments with artificial food items.
Egg size variation and its relationship with larval performance in the Lepidoptera: the case of the European grapevine moth Lobesia botrana
Authors: Torres‐Vila Luis M. , Rodríguez‐Molina M. Carmen
Published: March 2003

Life history theory attempts to define the pattern of resource distribution among offspring and predicts that egg size should be positively correlated with offspring fitness. In this paper we investigated the effect of an array of ecological and reproductive factors on the size of eggs laid by Lobesia botrana, and the ecological significance of egg size by experimentally testing whether or not egg size increased larval performance in this moth. Egg size was significantly affected by female age at mating, water availability, pupal weight loss, the phenological stage of the vine in which larvae developed, female body weight, and oviposition day, but was unaffected by the size of the spermatophore received. The greater the size of the first eggs produced, the smaller the size of the last eggs laid, as predicted by the resource depletion hypothesis. As expected, the larger the size of eggs the larger the size of larvae emerging from them. Large larvae displayed a better ability to endure starvation than small ones. When small and large larvae were allowed to develop on grape clusters, an adverse environment, large larvae performed better, settling and survival being significantly enhanced, almost tripled. Instead, when the same experiment was carried out on an artificial diet in the laboratory, a much more favourable milieu, survival in both sized‐larval groups was not significantly different. We discuss our results in the context of current ideas relating egg size, larval performance and fitness in the Lepidoptera.
Maternal environmental effects on the phenotypic responses of the twining vine Ipomoea purpurea to support availability
Authors: Gianoli Ernesto
Published: March 2003

The presence of physical support elicits a number of morphological changes in the shoot of the common morning glory Ipomoea purpurea, including a shortening of internodes and petioles and a thickening of the main stem. Working with experimentally supported and non‐supported plants of I. purpurea, I tested the existence of maternal environmental effects of physical support in this twining vine. I evaluated whether the offspring of supported plants differed from the offspring of non‐supported plants in a number of morphological and reproductive characters. Stem diameter was the only shoot trait that showed a significant effect of the maternal environment (support). The stems of the progeny of supported mother plants were thicker than the stems of the progeny of non‐supported mother plants. This was true for both supported and non‐supported progeny. Stem diameter, however, was not significantly related to plant fitness (seed number) in supported or non‐supported progeny plants. The maternal environment did not affect the magnitude of the phenotypic responses to support of shoot traits in the progeny plants. There were no maternal environmental effects of physical support on the proportion of flowering plants at week 10 in both non‐supported and supported progeny. Likewise, the presence of physical support in the maternal environment did not affect reproductive traits (seed number, seed size, percentage of reproductive biomass) in supported and non‐supported progeny plants. Finally, the relationship between seed size and seed number was affected by the maternal support environment. The progeny of supported mother plants showed a significantly negative association (trade‐off) between seed size and number, whereas such a trade‐off was not observed in the progeny of non‐supported plants. This was true for both supported and non‐supported progeny.
Juvenile ossifying fibroma. An analysis of eight cases and a comparison with other fibro‐osseous lesions
Authors: Williams H. K. , Mangham C. , Speight P. M.
Published: March 2003

Abstract: Juvenile ossifying fibroma (JOF) is a well‐defined clinical and histological entity that has recently been separated from other fibro‐osseous lesions, including cemento‐ossifying fibromas. Its biological behaviour is well defined, but unexplained. Its behaviour, clinical and histological appearance, however, bears resemblance to osteofibrous dysplasia of long bones, a lesion that in some cases has been reported to be part of a spectrum of diseases associated with adamantinoma, thus accounting for its variable biological behaviour. Eight cases of JOF were examined for islands of epithelium or single epithelial cells using immunocytochemistry. While these cases of JOF could clearly be separated from other fibro‐osseous lesions, and were histologically similar to osteofibrous dysplasia, the absence of cytokeratin‐positive cells in all cases suggests that another reason for its biological behaviour has still to be found.
A novel cell line that retains the morphological characteristics of the cells and matrix of odontogenic myxoma
Authors: Jaeger Márcia , Santos Jean , Domingues Manoela , Ruano Rogério , Araújo Ney , Caroli André , Jaeger Ruy
Published: March 2003

Abstract: Little is known about the histogenesis of the human odontogenic myxoma or the relation between tumour cells and the matrix. In order to attempt to remedy this situation, we established and investigated a cell line derived from a human odontogenic myxoma. To our knowledge this is the first cell line derived from this tumour. The cell line, named Mix 1, preserved features of the tumour cells. Mix 1 cells expressed vimentin, type I collagen, fibronectin, tenascin and hyaluronic acid. Ultrastructural analysis of cells of the tumour and cell line demonstrated similarities, both containing Golgi apparatus, rough endoplasmic reticulum and mitochondria indicative of secretory cells. Ultrastructural analysis showed the matrix to be represented by bundles of collagen fibrils in the tumour, and by irregular filaments in cultures more than 60 days old. The Mix 1 cell line promises to be an excellent model for investigating the biology of the odontogenic myxoma.
A study to assess inducible nitric oxide synthase expression in oral lichen planus
Authors: Brennan Peter A. , Umar Tijjani , Palacios‐Callender Miriam , Spedding Anne V. , Mellor Timothy K. , Buckley Jayne , Langdon John D.
Published: March 2003

Abstract: Nitric oxide (NO) has been implicated in a variety of diseases but has not been previously studied in oral lichen planus (OLP). Since OLP has a complex immunogenesis with abundant macrophage infiltration, this study determined by immunohistochemistry whether or not the expression of the inducible form of nitric oxide synthase (iNOS) was increased in this condition relative to normal mucosa. Thirty cases of OLP and 10 normal buccal mucosa biopsies were studied utilising primary antibodies to iNOS and CD68, a myelomonocytic marker. iNOS activity was additionally assessed using a [14−C]‐labelled arginine to citrulline assay. CD68 expression was significantly increased in the cellular infiltrate of all 30 cases of OLP compared with normal mucosa (P<0.009). Although iNOS staining was seen in a minority of cells in nine cases, this was not statistically significant when compared with the absent staining in normal oral mucosa (P=0.26). Furthermore, the minimal iNOS activity found in OLP was similar to that in normal mucosa. We conclude that expression of iNOS by macrophages is downregulated in OLP and discuss the possible reasons for this finding.
Enamel defects in primary and permanent teeth of children born prematurely
Authors: Aine L. , Backström M. C. , Mäki R. , Kuusela A.‐L. , Koivisto A.‐M. , Ikonen R.‐S. , Mäki M.
Published: March 2003

Abstract: The objective of this study was to determine the prevalence of enamel defects in both primary and permanent dentitions of the same preterm children, and to elucidate the role of early dietary mineral and vitamin D intake in the etiology of the enamel defects. The status of the primary and permanent teeth was evaluated in 32 preterm children and in 64 control children. The prevalence of enamel defects in children born preterm was clearly higher as compared with controls in both the primary (78% vs 20%, P<0.001) and permanent (83% vs 36%, P<0.001) dentitions. Neither the mineral supplementation used nor a vitamin D dose of 1000 IU/day, as compared with a lower dose of 500 IU/day, reduced the prevalence of enamel defects in the primary or permanent dentitions. Further studies are needed to clarify whether achieving near optimum intra‐uterine mineral retention would lower the prevalence of subsequent enamel defects in infants born prematurely.
Specific inhibition of cyclooxygenase‐2 results in inhibition of proliferation of oral cancer cell lines via suppression of prostaglandin E2 production
Authors: Sumitani Kaname , Kamijo Ryutaro , Toyoshima Takahiko , Nakanishi Yuko , Takizawa Kunio , Hatori Masashi , Nagumo Masao
Published: March 2003

Abstract: Prostaglandins (PGs) are known to play important roles in the proliferation of various types of cancer cells. PGs are produced by the action of cyclooxygenase (COX) enzymes, and two forms of COX, COX‐1 and COX‐2, have been described. Previous studies have demonstrated that overexpression of COX‐2 is associated with colon carcinogenesis, tumor invasion and metastatic potential of colon cancer. In this study, the role of COX‐2 on proliferation of squamous cell carcinoma cell lines was investigated. NS‐398, a selective COX‐2 inhibitor, inhibited proliferation of NA cells, a squamous cell caricinoma cell line that constitutively expresses COX‐2 mRNA. NS‐398 suppressed the spontaneous production of PGE2 by NA cells, and the antiproliferative effect of NS‐398 was abolished by addition of PGE2. Similar results were obtained from experiments using COX‐2 antisense oligonucleotide. These results suggest that specific inhibition of COX‐2 inhibits proliferation of cancer cells expressing COX‐2 mRNA via suppression of PGE2 production.
Reduced expression of CD9 in oral squamous cell carcinoma: CD9 expression inversely related to high prevalence of lymph node metastasis
Authors: Kusukawa Jingo , Ryu Fuminori , Kameyama Tadamitsu , Mekada Eisuke
Published: March 2003

Abstract: Because CD9 is implicated in cell growth, cell adhesion and cell motility, altered CD9 expression might be involved in cancer invasion and metastasis. We have studied the immunolocalization of CD9 in oral squamous cell carcinoma (SCC). Sections prepared from paraffin‐embedded specimens from patients with SCC of the oral cavity were stained with a monoclonal anti‐CD9 antibody by means of the streptoavidin biotin method. Significant reduction or complete loss of CD9 expression was observed in cancer cells at the periphery of the cancer nests in the advancing front of invading tumor. Among 78 cases of oral SCCs examined, 46 (59.0%) cases were completely negative for CD9 expression. Loss of CD9 expression in cancer tissue strongly correlated with a high incidence of cervical lymph node metastasis and poorer prognosis (P=0.001). Thus a close examination of CD9 in SCC tissue would be useful for the prognosis of patients with oral carcinoma.
Serum antioxidant micronutrient levels in oral lichen planus
Authors: Nagao Toru , Warnakulasuriya Saman , Ikeda Noriaki , Fukano Hideo , Yamamoto Shigeo , Yano Masatoshi , Miyazaki Hideo , Ito Yoshinori
Published: March 2003

Abstract: The aim of this study was to elucidate any association between oral lichen planus (OLP) and serum antioxidant micronutrients by a population‐based case‐control study. A total of 9536 subjects were examined, and 62 (58 reticular, 4 atrophic and erosive) diagnosed with OLP at referral facilities were compared with four controls per case (n=248) selected among disease‐free subjects matched for age and sex. Serum levels of micronutrients (retinol, α‐tocopherol, zeaxanthin/lutein and cryptoxanthin, lycopene, α‐carotene and β‐carotene) were estimated by the high performence liquid chromatography (HPLC) method. Among cases, mean serum retinol level (2.820±0.849 μmol/l) was significantly higher compared with that of controls (2.562±0.735 μmol/l) (P<0.05). No significant differences were noted in carotenoid levels examined in this study, except for a lower level of lycopene found in atrophic/erosive OLP cases. The results of this study suggest that low serum retinol or carotenoid levels are not risk factors for occurrence of lichen planus, and any specific benefits of antioxidant micronutrients cannot be claimed for this inflammatory disorder.
Growth factors, extracellular matrix components and cell adhesion molecules in Warthin’s tumor
Authors: Nakamura Yasuhiro , Yamamoto Munehiko , Sakamoto Kikuo , Ohta Keiko , Umeda Akemi , Tsukamoto Takahisa , Nakashima Tadashi
Published: March 2003

Abstract: We studied expressions of various growth factors, their receptors, cell adhesion molecules and extracellular matrix components in Warthin’s tumor of the salivary gland with immunohistochemistry and reverse transcriptase‐polymerase chain reaction (RT‐PCR). Various growth factors and their receptors, such as transforming growth factor‐α (TGF‐α), heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF), TGF‐β2, TG‐β3, insulin‐like growth factor (IGF)‐I and ‐II, vascular endothelial growth factor (VEGF), EGF receptor (EGFR), erb‐B4, TGF‐βRI and II, Flt and Flk‐1 and IGF receptor Iβ, were found in epithelial cells and/or in some lymphoid cells. Fibronectin, laminin, collagen type IV and tenascin were found in stroma of the lymphoid tissue. Integrins such as α3β1 and β3, Thy‐1, CD44 and VCAM‐1 were also expressed in epithelial and/or lymphoid cells. These various proteins may interact and regulate the proliferation and cell attachment of both epithelial and lymphoid components in this unique tumor.
Helicobacter pylori colonization of tongue mucosa – increased incidence in atrophic glossitis and burning mouth syndrome (BMS)
Authors: Gall‐Trošelj K. , Mravak‐Stipetić M. , Jurak I. , Ragland W. L. , Pavelić J.
Published: March 2003

Abstract: Nested polymerase chain reaction (PCR) was performed to detect the presence of Helicobacter pylori in tongue mucosa in 268 patients divided into four groups according to their diagnosis: 87 with atrophic glossitis, 37 with benign migratory glossitis and 144 with burning mouth syndrome (BMS). The latter group was subdivided according to anatomic site of burning sensation: subgroup A (54 patients) with complaints limited to tongue and subgroup B (90 patients) with burning sensations in other parts of oral mucosa. H. pylori was found in 43 samples (16%). Bacteria were significantly less present in tongue mucosa affected with benign migratory glossitis compared with atrophic glossitis and BMS (P=0.025). This difference was more obvious when compared with atrophic glossitis only (P=0.006). Mucosal changes in these conditions might make the oral environment more acceptable for H. pylori colonization compared with normal mucosa, and this mechanism may play a role in its oro‐oral transmission.
Distribution of basement membrane type IV collagen α chains in ameloblastoma: an immunofluorescence study
Authors: Nakano Keisuke , Siar Chong Huat , Nagai Noriyuki , Naito Ichiro , Sado Yoshikazu , Nagatsuka Hitoshi , Hoh Choufuku , Kurada Katsuhiro , Tsujigiwa Hidetsugu , Gunduz Mehmet
Published: March 2003

Background:  Type IV collagen, a heterotrimeric molecule that exists in six genetically distinct forms, α1(IV)–α6(IV) is a major structural component of basement membrane (BM) and acts as a scaffold for other BM constituents.

Methods:  Indirect immunofluorescence using α chain‐specific monoclonal antibodies was employed to clarify basement membrane (BM) collagen IV distribution in two ameloblastoma, and for comparison, on oral mucosa and tooth germ.

Results:  Ameloblastoma BM expressed five of six genetically distinct forms of collagen IV: α1(IV), α2(IV), α5(IV) and α6(IV) chains occurred as intense linear stainings without disruption around neoplastic epithelium, and this expression pattern was fundamentally similar to oral mucosa BM; α4(IV) expression was rare and occurred around nests of primitive tumor cells or potentially invasive sites. The tooth germ demonstrated a stage‐ and position‐specific collagen IV distribution: the inner enamel epithelium BM expressed α1(IV), α2(IV), and α4(IV) except in the cuspal predentine region; and the outer enamel epithelium BM expressed α1(IV), α2(IV), α5(IV), and α6(IV) chains.

Conclusions:  Results suggest that collagen IV α chain distribution in ameloblastoma BM plays an important role in tumor cytodifferentiation and progression.