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Mechanical strain induces growth of vascular smooth muscle cells via autocrine action of PDGF.
The effect of cyclic mechanical strain on growth of neonatal rat vascular smooth muscle (VSM) cells were examined. Cells were grown on silicone elastomer plates subjected to cyclic strain (60 cycle/min) by application of a vacuum under the plates. A 48 h exposure to mechanical strain increased the basal rate of thymidine incorporation by threefold and increased cell number by 40% compared with cells grown on stationary rubber plates. Strain also increased the rate of thymidine incorporation in response to alpha-thrombin (from 15- to 33-fold), but not to PDGF. As determined by thymidine autoradiography, strain alone induced a fourfold increase in labeled nuclei at the periphery of dishes, where strain is maximal, and a 2-3-fold increase at the center of dishes. Strain appeared to induce the production of an autocrine growth factor(s), since conditioned medium from cells subjected to strain induced a fourfold increase in DNA synthesis in control cells. Western blots of medium conditioned on the cells subjected to strain indicate that the cells secrete both AA and BB forms of PDGF in response to strain. Northern blots of total cell RNA from cells exposed to strain for 24 h show increased steady-state level of mRNA for PDGF-A. Lastly, polyclonal antibodies to the AA form of PDGF reduced by 75% the mitogenic effect of strain and polyclonal antibodies to AB-PDGF reduced mitogenicity by 50%. Antibodies to bFGF did not significantly reduce the strain-induced thymidine incorporation. Thus, the mechanism of strain-induced growth appears to involve the intermediary action of secreted PDGF
Partially reconfigurable TVWS transceiver for use in UK and US markets
With more and more countries opening up sections of unlicensed spectrum for use by TV White Space (TVWS) devices, the prospect of building a device capable of operating in more than one world region is appealing. The difficulty is that the locations of TVWS bands within the radio spectrum are not globally harmonised. With this problem in mind, the purpose of this paper is to present a TVWS transceiver design which is capable of being reconfigured to operate in both the UK and US spectrum. We present three different configurations: one covering the UK TVWS spectrum and the remaining two covering the various locations of the US TVWS bands
Inner Planetary System Gap Complexity is a Predictor of Outer Giant Planets
The connection between inner small planets and outer giant planets is crucial
to our understanding of planet formation across a wide range of orbital
separations. While Kepler provided a plethora of compact multi-planet systems
at short separations ( AU), relatively little is known about the
occurrence of giant companions at larger separations and how they impact the
architectures of the inner systems. Here, we use the catalog of systems from
the Kepler Giant Planet Search (KGPS) to study how the architectures of the
inner transiting planets correlate with the presence of outer giant planets. We
find that for systems with at least three small transiting planets, the
distribution of inner-system gap complexity (), a measure of the
deviation from uniform spacings, appears to differ () between
those with an outer giant planet () and those without any outer giants. All four inner systems (with 3+
transiting planets) with outer giant(s) have a higher gap complexity
() than 79% (19/24) of the inner systems without any outer
giants (median ). This suggests that one can predict
the occurrence of outer giant companions by selecting multi-transiting systems
with highly irregular spacings. We do not find any correlation between outer
giant occurrence and the size (similarity or ordering) patterns of the inner
planets. The larger gap complexities of inner systems with an outer giant hints
that massive external planets play an important role in the formation and/or
disruption of the inner systems.Comment: Published in AJ. 16 pages, 6 figures, 1 tabl
Controlled Manipulation of Mode Splitting in an Optical Microcavity by Two Rayleigh Scatterers
We report controlled manipulation of mode splitting in an optical
microresonator coupled to two nanoprobes. It is demonstrated that, by
controlling the positions of the nanoprobes, the split modes can be tuned
simultaneously or individually and experience crossing or anti-crossing in
frequency and linewidth. A tunable transition between standing wave mode and
travelling wave mode is also observed. Underlying physics is discussed by
developing a two-scatterer model which can be extended to multiple scatterers.
Observed rich dynamics and tunability of split modes in a single microresonator
will find immediate applications in optical sensing, opto-mechanics, filters
and will provide a platform to study strong light-matter interactions in
two-mode cavities.Comment: 9 pages, 5 figures, 14 references. Major revision. Published version
in Optics Expres
Heat transport by turbulent Rayleigh-B\'enard convection for $\Pra\ \simeq 0.83\times 10^{12} \alt \Ra\ \alt 10^{15}\Gamma = 0.50$
We report experimental results for heat-transport measurements, in the form
of the Nusselt number \Nu, by turbulent Rayleigh-B\'enard convection in a
cylindrical sample of aspect ratio ( m is
the diameter and m the height). The measurements were made using
sulfur hexafluoride at pressures up to 19 bars as the fluid. They are for the
Rayleigh-number range 3\times 10^{12} \alt \Ra \alt 10^{15} and for Prandtl
numbers \Pra\ between 0.79 and 0.86. For \Ra < \Ra^*_1 \simeq 1.4\times
10^{13} we find \Nu = N_0 \Ra^{\gamma_{eff}} with , consistent with classical turbulent Rayleigh-B\'enard convection in a
system with laminar boundary layers below the top and above the bottom plate.
For \Ra^*_1 < \Ra < \Ra^*_2 (with \Ra^*_2 \simeq 5\times 10^{14})
gradually increases up to . We argue that above
\Ra^*_2 the system is in the ultimate state of convection where the boundary
layers, both thermal and kinetic, are also turbulent. Several previous
measurements for are re-examined and compared with the present
results.Comment: 44 pages, 18 figures, submitted to NJ
Achieving highly efficient gene transfer to the bladder by increasing the molecular weight of polymer-based nanoparticles
Short dwell-time and poor penetration of the bladder permeability barrier (BPB) are the main obstacles to intravesical treatments for bladder diseases, and is evidenced by the lack of such therapeutic options on the market. Herein, we demonstrate that by finely tuning the molecular weight of our cationic polymer mucoadhesive nanoparticles, we enhanced our gene transfer, leading to improved adherence and penetrance through the BPB in a safe and efficient manner. Specifically, increasing the polymer molecular weight from 45 kDa to 83 kDa enhanced luciferase plasmid transfer to the healthy murine bladder, leading to 1.35 ng/g luciferase protein expression in the urothelium and lamina propria regions. The relatively higher molecular weight polymer (83 kDa) did not induce morphologic changes or inflammatory responses in the bladder. This approach of altering polymer molecular weight for prolonging gene transfer residence time and deeper penetration through the BPB could be the basis for the design of future gene therapies for bladder diseases
Down-regulation of GP130 signaling sensitizes bladder cancer to cisplatin by impairing Ku70 DNA repair signaling and promoting apoptosis
Chemoresistance is one of the barriers for the development of bladder cancer treatments. Previously, we showed that glycoprotein-130 (GP130) is overexpressed in chemoresistant bladder cancer cells and that knocking down GP130 expression reduced cell viability. In our current work, we showed that down-regulation of GP130 sensitized bladder cancer cells to cisplatin-based chemotherapy by activating DNA repair signaling. We performed immunohistochemistry and demonstrated a positive correlation between the levels of Ku70, an initiator of canonical non-homologous end joining repair (c-NHEJ) and suppressor of apoptosis, and GP130 in human bladder cancer specimens. GP130 knockdown by SC144, a small molecule inhibitor, in combination with cisplatin, increased the number of DNA lesions, specifically DNA double-stranded breaks, with a subsequent increase in apoptosis and reduced cell viability. Furthermore, GP130 inhibition attenuated Ku70 expression in bladder and breast cancer cells as well as in transformed kidney cells. In addition, we fabricated a novel polymer-lipid hybrid delivery system to facilitate GP130 siRNA delivery that had a similar efficiency when compared with Lipofectamine, but induced less toxicity
Numerical renormalization group of vortex aggregation in 2D decaying turbulence: the role of three-body interactions
In this paper, we introduce a numerical renormalization group procedure which
permits long-time simulations of vortex dynamics and coalescence in a 2D
turbulent decaying fluid. The number of vortices decreases as ,
with instead of the value predicted by a na\"{\i}ve
kinetic theory. For short time, we find an effective exponent
consistent with previous simulations and experiments. We show that the mean
square displacement of surviving vortices grows as .
Introducing effective dynamics for two-body and three-body collisions, we
justify that only the latter become relevant at small vortex area coverage. A
kinetic theory consistent with this mechanism leads to . We find that
the theoretical relations between kinetic parameters are all in good agreement
with experiments.Comment: 23 RevTex pages including 7 EPS figures. Submitted to Phys. Rev. E
(Some typos corrected; see also cond-mat/9911032
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