435 research outputs found
Thermodynamic Scaling of the Viscosity of Van Der Waals, H-Bonded, and Ionic Liquids
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
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
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
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
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
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
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
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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