430 research outputs found

    Thermodynamic Scaling of the Viscosity of Van Der Waals, H-Bonded, and Ionic Liquids

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    Viscosities and their temperature, T, and volume, V, dependences are reported for 7 molecular liquids and polymers. In combination with literature viscosity data for 5 other liquids, we show that the superpositioning of relaxation times for various glass-forming materials when expressed as a function of TV^g, where the exponent g is a material constant, can be extended to the viscosity. The latter is usually measured to higher temperatures than the corresponding relaxation times, demonstrating the validity of the thermodynamic scaling throughout the supercooled and higher T regimes. The value of g for a given liquid principally reflects the magnitude of the intermolecular forces (e.g., steepness of the repulsive potential); thus, we find decreasing g in going from van der Waals fluids to ionic liquids. For strongly H-bonded materials, such as low molecular weight polypropylene glycol and water, the superpositioning fails, due to the non-trivial change of chemical structure (degree of H-bonding) with thermodynamic conditions.Comment: 16 pages 7 figure

    Role of hormonal risk factors in HER2-positive breast carcinomas

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    Examination of parity, age at menarche and at menopause by HER2 status in a large series of breast carcinomas showed a statistically significant increased-frequency of HER2-positive tumours in lower risk subgroups. The findings suggest a difference in the protective role of hormone-related risk factors between HER2-positive and -negative tumour

    Glassy dynamics in mono-, di-, and tri-propylene glycol: From the alpha- to the fast beta-relaxation

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    We present a thorough characterization of the glassy dynamics of three propylene glycols (mono-, di- and trimer) by broadband dielectric spectroscopy. By covering a frequency range of more than 15 decades, we have access to the entire variety of dynamic processes typical for glassy dynamics. These results add three more molecular glass formers to the sparse list of materials for which real broadband spectra, including the region of the fast beta-process, are available. Some first analyses of the various observed dynamic processes are provided

    Heregulin β1 induces the down regulation and the ubiquitin-proteasome degradation pathway of p185HER2 oncoprotein

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    AbstractAnalysis of the fate of the p185HER2 oncoprotein following activation by heregulin β1 revealed the induction of the tyrosine-phosphorylation, down-modulation, and polyubiquitination of p185HER2. Receptor ubiquitination was suppressed in cells treated with heregulin β1 in the presence of sodium azide, an inhibitor of ATP-dependent reactions, or genistein, a tyrosine kinase protein inhibitor, indicating the requirement for kinase activity and ATP in p185HER2 polyubiquitination. Ubiquitinated p185HER2 was degradated by the 26S proteasome proteolytic pathway. Kinetics and inhibition experiments indicated that endocytosis of the receptor occurs downstream of the initiation of the degradation process

    Effect of Chemical Structure on the Isobaric and Isochoric Fragility in Polychlorinated Biphenyls

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    Pressure-volume-temperature data, along with dielectric relaxation measurements, are reported for a series of polychlorinated biphenyls (PCB), differing in the number of chlorine atoms on their phenyl rings. Analysis of the results reveals that with increasing chlorine content, the relaxation times of the PCB become governed to a greater degree by density, rho, relative to the effect of temperature, T. This result is consistent with the respective magnitudes of the scaling exponent, gamma, yielding superpositioning of the relaxation times measured at various temperatures and pressures, when plotted versus rho^gamma/T. While at constant (atmospheric) pressure, fragilities for the various PCB are equivalent, the fragility at constant volume varies inversely with chlorine content. Evidently, the presence of bulkier chlorine atoms on the phenyl rings magnifies the effect density has on the relaxation dynamics.Comment: 20 pages 5 figure

    Breast tumors: an overview

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    Review on Breast tumors: an overview, with data on clinics, and the genes involved

    Influence of harvesting techniques, grape crushing and wine treatments on the volatile components of white wines

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    Trebbiano white grapes were harvested both by hand and mechanically, with the addition of O2 and SO2 at crushing in the vineyard. After wine-making in standard conditions, the wines were cla rified with different fining agents.The wines were tested to identify the volatile components. The method developed included solvent extraction, concentration, GLC and GLC/MS an alysis. Over 60 compounds were ide ntified, some of which were previously unidentified.Only some volatile components were significantly affected by the harvesting techniques or by clarification treatments. The hyperoxygenation of the crushed grapes lowered the aroma profile, improving the content of the more oxidized molecules. The S02 addition increased maceration phenomena, but decreased wine stability to browning reactions. The wine finishing with bentonite and other clarifying additives resulted in a loss of some aroma compounds due to volatilization

    Evaluation of reproductive performances of the common octopus (Octopus vulgaris) reared in water recirculation systems and fed different diets

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    The reproductive performance of Octopus vulgaris broodstocks fed two different diets (mixed fish [F group, BW 1,048.14 g] or mixed crustaceans [C group, BW 998.44 g]) was analyzed using an experimental recirculating aquaculture system consisting of a tank equipped with spawning and incubation chambers. A total of 8 females (F1–4; C1–4), and 8 males (M1–M8) were selected. DI of the C group females was significantly (p < 0.05) higher (3.0 ± 0.29%) than the F group (2.16 ± 0.67%). SGR in C group was significantly higher (1.43 ± 0.12%) than the F group (1.18 ± 0.25%). Egg clusters, number of clusters, number of clusters/kg BW, and total length were more favorable in the C group than the F group. The number of clusters/kg BW of C females was 2.5 times higher than that of F females (78.1 ± 6.5 vs 31.1 ± 13.3). The total eggs number, number of eggs/cm, number of eggs/kg BW in the C group were significantly (p < 0.05) higher compared with the F group; the number of eggs/kg BW and paralarvae/kg BW were 5 times higher in the C group (115,928 ± 12,513 C vs 22,109 ± 7912 F and 114,953 ± 12,591 vs 20,729 ± 7104, respectively). Hatching rate of the C group was significantly (p < 0.05) higher compared to the F grou
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