967 resultados para Anomalous secondary growth


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CLIL instruction has been reported to be beneficial for foreign language vocabulary learning since CLIL students show higher vocabulary profiles than students of their same age in traditional EFL contexts. However, to our knowledge, the receptive vocabulary knowledge of CLIL and non-CLIL learners at the end of primary and secondary education has not been examined yet. Hence, this study aims at comparing the receptive vocabulary size 79 CLIL primary learners with the receptive vocabulary knowledge of 331 non-CLIL learners at the end of primary and secondary school. Sex-based differences were also analysed. The 2k Vocabulary Levels Test (VLT) was used for the purposes of the study. Results revealed that learners’ receptive vocabulary sizes lie within the most frequent 1000 words, non-CLIL secondary school students throw better results than primary students but the differences between the secondary group and the CLIL group are not statistically significant. As for sex-based differences, we found no significant differences among the groups. These findings led us to believe that the CLIL approach offers a benefit for vocabulary acquisition since CLIL learners have been exposed to the foreign language for a shorter period of time and the results are quite similar to their non-CLIL secondary school partners.

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Acquired resistance to selective FLT3 inhibitors is an emerging clinical problem in the treatment of FLT3-ITD(+) acute myeloid leukaemia (AML). The paucity of valid pre-clinical models has restricted investigations to determine the mechanism of acquired therapeutic resistance, thereby limiting the development of effective treatments. We generated selective FLT3 inhibitor-resistant cells by treating the FLT3-ITD(+) human AML cell line MOLM-13 in vitro with the FLT3-selective inhibitor MLN518, and validated the resistant phenotype in vivo and in vitro. The resistant cells, MOLM-13-RES, harboured a new D835Y tyrosine kinase domain (TKD) mutation on the FLT3-ITD(+) allele. Acquired TKD mutations, including D835Y, have recently been identified in FLT3-ITD(+) patients relapsing after treatment with the novel FLT3 inhibitor, AC220. Consistent with this clinical pattern of resistance, MOLM-13-RES cells displayed high relative resistance to AC220 and Sorafenib. Furthermore, treatment of MOLM-13-RES cells with AC220 lead to loss of the FLT3 wild-type allele and the duplication of the FLT3-ITD-D835Y allele. Our FLT3-Aurora kinase inhibitor, CCT137690, successfully inhibited growth of FLT3-ITD-D835Y cells in vitro and in vivo, suggesting that dual FLT3-Aurora inhibition may overcome selective FLT3 inhibitor resistance, in part due to inhibition of Aurora kinase, and may benefit patients with FLT3-mutated AML.

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County engineers in Iowa face the dual problems of rapidly escalating costs and a decreasing rate of growth of revenues. Various priority systems are in use, ranking projects for inclusion in road improvement programs, but they generally have weaknesses when used to compare one project with another in a different location. The sufficiency rating system has proven to be a useful tool in developing a priority list of projects for primary road systems, but there are none currently in use for secondary road systems. Some elements of an existing system used for primary roads could be modified for use with secondary roads, but would require extensive changes. The research reported here, sponsored by the Iowa Department of Transportation, was undertaken to develop a sufficiency rating system which could be used for secondary roads in Iowa and to produce the necessary forms and instructions to aid county engineering personnel in their efforts to complete the ratings for roads within their county. If a usable system were available that would yield reasonable results, county engineers would have an additional tool available to assist them in arriving at a defensible road improvement program.

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Normal grain growth of calcite was investigated by combining grain size analysis of calcite across the contact aureole of the Adamello pluton, and grain growth modeling based on a thermal model of the surroundings of the pluton. In an unbiased model system, i.e., location dependent variations in temperature-time path, 2/3 and 1/3 of grain growth occurs during pro- and retrograde metamorphism at all locations, respectively. In contrast to this idealized situation, in the field example three groups can be distinguished, which are characterized by variations in their grain size versus temperature relationships: Group I occurs at low temperatures and the grain size remains constant because nano-scale second phase particles of organic origin inhibit grain growth in the calcite aggregates under these conditions. In the presence of an aqueous fluid, these second phases decay at a temperature of about 350 °C enabling the onset of grain growth in calcite. In the following growth period, fluid-enhanced group II and slower group III growth occurs. For group II a continuous and intense grain size increase with T is typical while the grain growth decreases with T for group III. None of the observed trends correlate with experimentally based grain growth kinetics, probably due to differences between nature and experiment which have not yet been investigated (e.g., porosity, second phases). Therefore, grain growth modeling was used to iteratively improve the correlation between measured and modeled grain sizes by optimizing activation energy (Q), pre-exponential factor (k0) and grain size exponent (n). For n=2, Q of 350 kJ/mol, k0 of 1.7×1021 μmns−1 and Q of 35 kJ/mol, k0 of 2.5×10-5 μmns−1 were obtained for group II and III, respectively. With respect to future work, field-data based grain growth modeling might be a promising tool for investigating the influences of secondary effects like porosity and second phases on grain growth in nature, and to unravel differences between nature and experiment.

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New antibacterial compounds, preferentially exploiting novel cellular targets, are urgently needed to fight the increasing resistance of pathogens against conventional antibiotics. Here we demonstrate that Carolacton, a myxobacterial secondary metabolite previously shown to damage Streptococcus mutans biofilms, inhibits planktonic growth of Streptococcus pneumoniae TIGR4 and multidrug-resistant clinical isolates of serotype 19A at nanomolar concentrations. A Carolacton diastereomer is inactive in both streptococci, indicating a highly specific interaction with a conserved cellular target. S. mutans requires the eukaryotic-like serine/threonine protein kinase PknB and the cysteine metabolism regulator CysR for susceptibility to Carolacton, whereas their homologues are not needed in S. pneumoniae, suggesting a specific function for S. mutans biofilms only. A bactericidal effect of Carolacton was observed for S. pneumoniae TIGR4, with a reduction of cell numbers by 3 log units. The clinical pneumonia isolate Sp49 showed immediate growth arrest and cell lysis, suggesting a bacteriolytic effect of Carolacton. Carolacton treatment caused a reduction in membrane potential, but not membrane integrity, and transcriptome analysis revealed compensatory reactions of the cell. Our data show that Carolacton might have potential for treating pneumococcal infections.

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This paper reports a direct observation of an interesting split of the (022)(022) four-beam secondary peak into two (022) and (022) three-beam peaks, in a synchrotron radiation Renninger scan (phi-scan), as an evidence of the layer tetragonal distortion in two InGaP/GaAs (001) epitaxial structures with different thicknesses. The thickness, composition, (a perpendicular to) perpendicular lattice parameter, and (01) in-plane lattice parameter of the two epitaxial ternary layers were obtained from rocking curves (omega-scan) as well as from the simulation of the (022)(022) split, and then, it allowed for the determination of the perpendicular and parallel (in-plane) strains. Furthermore, (022)(022) omega:phi mappings were measured in order to exhibit the multiple diffraction condition of this four-beam case with their split measurement.

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Laboratory chamber experiments are used to investigate formation of secondary organic aerosol (SOA) from biogenic and anthropogenic precursors under a variety of environmental conditions. Simulations of these experiments test our understanding of the prevailing chemistry of SOA formation as well as the dynamic processes occurring in the chamber itself. One dynamic process occurring in the chamber that was only recently recognized is the deposition of vapor species to the Teflon walls of the chamber. Low-volatility products formed from the oxidation of volatile organic compounds (VOCs) deposit on the walls rather than forming SOA, decreasing the amount of SOA formed (quantified as the SOA yield: mass of SOA formed per mass of VOC reacted). In this work, several modeling studies are presented that address the effect of vapor wall deposition on SOA formation in chambers.

A coupled vapor-particle dynamics model is used to examine the competition among the rates of gas-phase oxidation to low volatility products, wall deposition of these products, and mass transfer to the particle phase. The relative time scales of these rates control the amount of SOA formed by affecting the influence of vapor wall deposition. Simulations show that an effect on SOA yield of changing the vapor-particle mass transfer rate is only observed when SOA formation is kinetically limited. For systems with kinetically limited SOA formation, increasing the rate of vapor-particle mass transfer by increasing the concentration of seed particles is an effective way to minimize the effect of vapor wall deposition.

This coupled vapor-particle dynamics model is then applied to α-pinene ozonolysis SOA experiments. Experiments show that the SOA yield is affected when changing the oxidation rate but not when changing the rate of gas-particle mass transfer by changing the concentration of seed particles. Model simulations show that the absence of an effect of changing the seed particle concentration is consistent with SOA formation being governed by quasi-equilibrium growth, in which gas-particle equilibrium is established much faster than the rate of change of the gas-phase concentration. The observed effect of oxidation rate on SOA yield arises due to the presence of vapor wall deposition: gas-phase oxidation products are produced more quickly and condense preferentially onto seed particles before being lost to the walls. Therefore, for α-pinene ozonolysis, increasing the oxidation rate is the most effective way to mitigate the influence of vapor wall deposition.

Finally, the detailed model GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) is used to simulate α-pinene photooxidation SOA experiments. Unexpectedly, α-pinene OH oxidation experiments show no effect when changing either the oxidation rate or the vapor-particle mass transfer rate, whereas GECKO-A predicts that changing the oxidation rate should drastically affect the SOA yield. Sensitivity studies show that the assumed magnitude of the vapor wall deposition rate can greatly affect conclusions drawn from comparisons between simulations and experiments. If vapor wall loss in the Caltech chamber is of order 10-5 s-1, GECKO-A greatly overpredicts SOA during high UV experiments, likely due to an overprediction of second-generation products. However, if instead vapor wall loss in the Caltech chamber is of order 10-3 s-1, GECKO-A greatly underpredicts SOA during low UV experiments, possibly due to missing autoxidation pathways in the α-pinene mechanism.

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Adjuvant-induced arthritis in rats is associated with growth failure, hypermetabolism and accelerated protein breakdown. The aim of this work was to study the effects of adjuvant-induced arthritis on GH and insulin-like growth factor-I (IGF-I). Arthritis was induced by an intradermal injection of complete Freund's adjuvant and rats were killed 18 and 22 days later. IGF-I and GH levels were measured by radioimmunoassay. Pituitary GH mRNA was analyzed by northern blot and IGF binding proteins (IGFBPs) by western blot. Arthritic rats showed a decrease in both serum and hepatic concentrations of IGF-I. On the contrary, arthritis increased the circulating IGFBPs. The serum concentration of IGF-I in the arthritic rats was negatively correlated with the body weight loss observed in these animals. Arthritis decreased the serum concentration of GH and this decrease seems to be due to an inhibition of GH synthesis, since pituitary GH mRNA content was decreased in arthritic rats (p<0.01). These data suggest that the decrease in body weight gain in arthritic rats may be, at least in part, secondary to the decrease in GH and IGF-I secretion. Furthermore, the increased serum IGFBPs may also be involved in the disease process.

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This study tests two general and independent hypotheses with the basic assumption that phytoactive secondary compounds produced by plants evolved primarily as plant defences against competitor plant species. The first hypothesis is that the production and main way of release of phytoactive compounds reflect an adaptive response to climatic conditions. Thus, higher phytoactivity by volatile compounds prevails in plants of hot, dry environments, whereas higher phytoactivity by water-soluble compounds is preponderant in plants from wetter environments. The second hypothesis is that synergy between plant phytoactive compounds is widespread, due to the resulting higher energy efficiency and economy of resources. The first hypothesis was tested on germination and early growth of cucumber treated with either water extracts or volatiles from leaves or vegetative shoot tops of four Mediterranean-type shrubs. The second hypothesis was tested on germination of subterranean clover treated with either water extracts of leaves or vegetative shoot tops of one tree and of three Mediterranean-type shrubs or with each of the three fractions obtained from water extracts. Our data do not support either hypotheses. We found no evidence for higher phytoactivity in volatile compounds released by plants that thrive in hot, dry Mediterranean-type environments. We also found no evidence for the predominance of synergy among the constituents of fractions. To the contrary, we found either antagonism or no interaction of effects among allelopathic compounds.

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Background:In vitrocell suspension cultivation systems have been largely reported assafe and standardized methods for production of secondary metabolites with medicinaland agricultural interest.Capsicum annuumis one of the most widely grown vegetablein the world and its biological activities have been demonstrated against insects, fungi,bacteria and other groups of organisms. The determination of procedures for thededifferentiation of cells into callus cells and the subsequent study of the callus growthpattern are necessary for the establishment of cellsuspensions and also to subsidizestudies regarding the bioactivity of its secondarymetabolites. To date, no study hasdescribed the development of protocols for callus induction inC. annuumL. cv. Etna. Objective:The objective of this study was to establish a protocol for dedifferentiationof leaf cells of the cultivarC. annuumcv. Etna and to determine the growth pattern ofthe calluses with a focus on the deceleration phase, when the callus cells must besubcultured into a liquid medium in order to establish cell suspension cultivationsaiming at the production of secondary metabolites.Results:The treatment that resultedin the highest %CI, ACCC and callus weight was thecombination of 4.52 μ M 2,4-D +0.44 μ M BA. The calluses produced were friable andwhitish and their growth patternfollowed a sigmoid shape. The deceleration phase started on the 23rdday of cultivation.Conclusion:Callus induction in leaf explants ofC. annuumcv. Etnacan be achieved inMS medium supplemented with 4.52 μ M 2,4-D + 0.44 μ MBA, which results in highcellular proliferation; in order to start a cell suspension culture, callus cells on the 23rdday of culture should be used.