188,689 research outputs found
MKP1 mediates resistance to therapy in HER2-positive breast tumors.
Mitogen-activated protein kinase phosphatase 1 (MKP1 or DUSP1) is an antiapoptotic phosphatase that is overexpressed in many cancers, including breast cancer. MKP1 expression is inducible in radiation-treated breast cancer cells, and correlates with human epidermal growth factor receptor 2 (ERBB2, HER2) expression. The role of MKP1 in therapy resistance suggests that targeting MKP1 in HER2-positive breast tumors may significantly enhance the efficacy of anti-HER2 and other anticancer therapies
Carbon Nanotube Thermal Transport: Ballistic to Diffusive
We propose to use l_0/(l_0+L) for the energy transmission covering both
ballistic and diffusive regimes, where l_0 is mean free path and L is system
length. This formula is applied to heat conduction in carbon nanotubes (CNTs).
Calculations of thermal conduction show: (1) Thermal conductance at room
temperature is proportional to the diameter of CNTs for single-walled CNTs
(SWCNTs) and to the square of diameter for multi-walled CNTs (MWCNTs). (2)
Interfaces play an important role in thermal conduction in CNTs due to the
symmetry of CNTs vibrational modes. (3) When the phonon mean free path is
comparable with the length L of CNTs in ballistic-diffusive regime, thermal
conductivity \kappa goes as L^{\alpha} . The effective exponent \alpha is
numerically found to decrease with increasing temperature and is insensitive to
the diameter of SWCNTs for Umklapp scattering process. For short SWCNTs (<0.1
\mu m) we find \alpha \approx 0.8 at room temperature. These results are
consistent with recent experimental findings.Comment: 4 pages, two figure
Dimensional crossover of thermal conductance in nanowires
Dimensional dependence of thermal conductance at low temperatures in
nanowires is studied using the nonequilibrium Green's function (NEGF) method.
Our calculation shows a smooth dimensional crossover of thermal conductance in
nanowire from one-dimensional to three-dimensional behavior with the increase
of diameters. The results are consistent with the experimental findings that
the temperature dependence of thermal conductance at low temperature for
diameters from tens to hundreds nanometers will be close to Debye law. The
calculation also suggests that universal thermal conductance is only observable
in nanowires with small diameters. We also find that the interfacial thermal
conductance across Si and Ge nanowire is much lower than the corresponding
value in bulk materials.Comment: 4 figure
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