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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 40 (2005), S. 251-258 
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In the context of the littlest Higgs (LH) model, we study the process $e^{ + }e^{-}\rightarrow t\bar{t}$ . We find that the new gauge bosons Z H and B H can produce significant correction effects on this process, which can be further enhanced by suitably polarized beams. In most of the parameter space preferred by the electroweak precision data, the absolute value of the relative correction parameter $R_{B_{H}}$ is larger than 5 %. As long as $1 {\mathrm {TeV}} \leq M_{Z_{H}}\leq 1.5 {\mathrm {TeV}} $ and $0.3\leq c\leq 0.5,$ the absolute value of the relative correction parameter $R_{Z_{H}}$ is larger than $5\%$ . With reasonable values of the parameters of the LH model, the possible signals of the new gauge bosons B H and Z H can be detected via the process $e^{ + }e^{-}\rightarrow t\bar{t}$ in the future LC experiments with the CM energy $\sqrt{S} = 800 {\mathrm {GeV}} $ . B H exchange and Z H exchange can generate significantly corrections to the forward-backward asymmetry $A_{\mathrm {{FB}}}(t\bar{t})$ only in a small part of the parameter space.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0649
    Keywords: 42.55.M ; 42.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Spectral broadening of stimulated Raman scattering has been studied in a phenylethanol liquid-core wave-guide optical fiber by using a frequency-doubled Q-switched Nd: YAG laser. Four orders of Stokes lines were observed. All the Stokes lines were asymmetrically broadened favoring the lower frequencies. Both the red-shifted broadening and the blue-shifted broadening increased with the rise of the temperature of the Raman medium. The asymmetric broadening was discussed to be mainly due to the effect of the cascaded stimulated Rayleigh-wing scattering.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1436-5073
    Keywords: Keywords. derivative spectrophotometry; rare earth determination; 6,8-fluoroquinolones; lomefloxacin.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract.  The second derivative spectrophotometric method has been developed as a procedure for the determination of neodymium, holmium and erbium in mixed rare earths. It was found that the 1-ethyl-6, 8-difluoro-7-(3-methyl-1-piperazinyl)-4-oxo-1,4- dihydro-3-quinoline carboxylic acid forms stable complexes with neodymium, holmium and erbium ions in the pH 9.2–10.5 range. In the second derivative spectra the optimum analytical signals for neodymium, holmium and erbium are at 576.2 (+)−574.5 (−)nm, 444.2 (+) −447.8 (−)nm and 516.0 (+) −517.2(−)nm, respectively. Beer’s law is obeyed from 5.0×10−5 M to 2.5×10−4 M of neodymium, holmium and erbium. The quantification limits (10 Sb) were 1.2×10−5 M for Nd, 9.7×10−5 M for Ho and 3.0×10−6 M for Er.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Norfloxacin (NFX) is proposed as reagent for the derivative spectrophotometric determination of neodymium, holmium and erbium in mixed rare earths. The absorption spectra of 4f electron transitions of the systems of neodymium, holmium and erbium complexes with norfloxacin in presence of cetylpyridinium chloride were studied by normal and derivative spectra. The absorption bands found normally at 575 nm for neodymium, 450 nm for holmium and 523 nm for erbium were enhanced markedly. Using the second derivative spectrum, Beer’s Law is obeyed from 5.0 × 10–5∼ 2.5 × 10–4 mol dm–3 for neodymium, holmium and erbium. The relative standard deviations are 1.0, 1.4 and 1.1% for 6.9 × 10–5 mol dm–3 of neodymium, 6.1 × 10–5 mol dm–3 of holmium and 6.0 × 10–5 mol dm–3 of erbium, respectively. A method for the direct determination of neodymium, holmium and erbium in mixtures of rare earth elements with good accuracy and selectivity, is described.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1335
    Keywords: Key words Nasopharyngeal carcinoma ; cDNA array hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: To investigate genes of critical areas, including cell cycle/growth control, apoptosis, oncogene/tumor suppressors and growth factor/cytokines, that are differentially expressed in nasopharyngeal carcinoma. Methods: The Human Cancer cDNA Atlas, which contains 588 genes relating to tumor biology, was used to screen normal nasopharyngeal tissue, nasopharyngeal cancer (NPC). The reverse transcription/polymerase chain reaction was used to confirm the expression pattern of some genes identified by Atlas hybridization. Results: The differentially expressed cell cycle/growth control regulators in NPC showed a stronger tendency toward cell proliferation with the up-regulation of cyclin D1, cyclin D2 etc. The expression pattern of apoptosis-related genes demonstrated the up-regulation of both anti-apoptotic factors such as the BCL-2-related protein A1, TRAF3, the inhibitor of apoptosis protein A1 (IAP1) and apoptotic pathway elements such as Fas/Apo-1, Apo-2 ligand etc. Among oncogenes/tumor suppressors, MDM2, STAT1 and STAT2 were found to be up-regulated in NPC. The expression profile of growth factors/cytokines showed the up-regulation of many growth-enhancing factors such as EGR1, tumor-derived growth factor 1, platelet-derived growth factor A chain etc. as well as Th1-type cytokines e.g. interleukin-1β and interferons. A smaller number of genes were down-regulated in nasopharyngeal cancer, such as those encoding ERK1, Raf, secreted apoptosis-related protein 1, CD27BP, transforming growth factor β2, pre-B-cell-stimulating factor homologue etc. Conclusion: The consistent tendency toward cell proliferation, the possibility of a stronger anti-apoptotic force that operates on the normal apoptotic pathway, or the autocrine or paracrine growth factors may account for the development of NPC. Some genes are reported for the first time to have changed expression in nasopharyngeal carcinoma. The simple, quick, and high-throughput method of profiling gene expression by cDNA array hybridization provides us with a quick overview of key factors that may be involved in NPC, and may identify genes suitable for further study of carcinogenesis mechanism or targets for possible molecular diagnosis or therapy.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A series of new complexes [RuL2(pdphen)]2+, where pdphen is the planar ligand pyridino[3,2-f] [1,7]phenanthroline and L = 2,2′-bipyridine, phenanthroline, 2,9-dimethylphenanthroline or 5-nitrophenanthroline, were prepared and characterized. The binding of [RuL2-(pdphen)] 2+ to calf thymus DNA was investigated using absorption, fluorescence and circular dichroism (c.d.) spectroscopies. All of the complexes show absorption hypochromicity associated with binding to calf thymus DNA. [Ru(bipy)2pdphen]2+ and [Ru(phen)2pdphen]2+ also show fluorescence intensities and excited state life-time increases. The c.d. spectra of dialyzates from solutions of racemic complexes versus calf thymus DNA indicate enantioselectivity associated with binding to DNA.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 33 (1995), S. 149-165 
    ISSN: 1573-4927
    Keywords: Drosophila ; metabolic regulation ; selection ; diet ; induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A diet medium containing 10% (w/v) sucrose can be inferred to be stressful toDrosophila melanogaster from the increased developmental time and reduced size and fecundity of emerging flies. The metabolic basis for this stress and the genetic response to it are of interest from the point of view of both metabolic regulation and the evolutionary genetics of adaptation to stress. Here the effects of a high-sucrose diet on live weight, total protein, stored lipid and glycogen, and crude activities of 12 enzymes involved in energy metabolism were quantified. Assays were done on a large population ofDrosophila that had been acclimated to the laboratory. A collection of eggs was divided to produce two replicate populations maintained on standard medium and two replicates maintained on high-sucrose medium for 133 generations. At the end of this period, both control and sucrose-selected populations were tested on standard and on high-sucrose medium. Results showed that the immediate effect of the high-sucrose diet (compared to standard medium) for both populations was a reduction in live weight and total protein, and activities of many of the enzymes were also reduced by the sucrose treatment, even after adjusting for the weight effect. Selection resulted in several changes on both the standard and the sucrose medium, but the direction of change was not always the same as the acute effect. In no case was there a significant medium by selection-treatment interaction. The pattern of phenotypic correlations did not resolve the reasons for the direction of the genetic responses. Correlations were generally stable across diets and after selection, but there were notable exceptions.
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  • 8
    Publication Date: 2016-08-03
    Description: Damming is one of the dramatic impacts to river food webs due to habitat fragmentation and changes in the hydrological regimes. The world’s largest dam, the Three Gorges Dam (TGD), has been constructed in the ...
    Electronic ISSN: 2192-1709
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Springer
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  • 9
    Publication Date: 2017-04-05
    Description: Alginate lyase is a biocatalyst that degrades alginate to produce oligosaccharides, which have many bioactive functions and could be used as renewable biofuels. Here we report a simple and sensitive plate assa...
    Electronic ISSN: 2191-0855
    Topics: Biology
    Published by Springer
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