Paxillin facilitates timely neurite initiation on soft-substrate environments by interacting with the endocytic machinery.

Neurite initiation is the first step in neuronal development and occurs spontaneously in soft tissue environments. Although the mechanisms regulating the morphology of migratory cells on rigid substrates in cell culture are widely known, how soft environments modulate neurite initiation remains elusive. Using hydrogel cultures, pharmacologic inhibition, and genetic approaches, we reveal that paxillin-linked endocytosis and adhesion are components of a bistable switch controlling neurite initiation in a substrate modulus-dependent manner. On soft substrates, most paxillin binds to endocytic factors and facilitates vesicle invagination, elevating neuritogenic Rac1 activity and expression of genes encoding the endocytic machinery. By contrast, on rigid substrates, cells develop extensive adhesions, increase RhoA activity and sequester paxillin from the endocytic machinery, thereby delaying neurite initiation. Our results highlight paxillin as a core molecule in substrate modulus-controlled morphogenesis and define a mechanism whereby neuronal cells respond to environments exhibiting varying mechanical properties

A Unified Approach to Nonlinear Dynamic Inversion Control with Parameter Determination by Eigenvalue Assignment

This paper presents a unified approach to nonlinear dynamic inversion control algorithm with the parameters for desired dynamics determined by using an eigenvalue assignment method, which may be applied in a very straightforward and convenient way. By using this method, it is not necessary to transform the nonlinear equations into linear equations by feedback linearization before beginning control designs. The applications of this method are not limited to affine nonlinear control systems or limited to minimum phase problems if the eigenvalues of error dynamics are carefully assigned so that the desired dynamics is stable. The control design by using this method is shown to be robust to modeling uncertainties. To validate the theory, the design of a UAV control system is presented as an example. Numerical simulations show the performance of the design to be quite remarkable

Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW) solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs) declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells

Partition function zeros of the Q-state Potts model for non-integer Q

The distribution of the zeros of the partition function in the complex temperature plane (Fisher zeros) of the two-dimensional Q-state Potts model is studied for non-integer Q. On $L\times L$ self-dual lattices studied ($L\le8$), no Fisher zero lies on the unit circle $p_0=e^{i\theta}$ in the complex $p=(e^{\beta J}-1)/\sqrt{Q}$ plane for Q<1, while some of the Fisher zeros lie on the unit circle for Q>1 and the number of such zeros increases with increasing Q. The ferromagnetic and antiferromagnetic properties of the Potts model are investigated using the distribution of the Fisher zeros. For the Potts ferromagnet we verify the den Nijs formula for the thermal exponent $y_t$. For the Potts antiferromagnet we also verify the Baxter conjecture for the critical temperature and present new results for the thermal exponents in the range 0<Q<3.Comment: 12 pages, 7 figures, RevTe

A mixture of anatase and rutile TiO2 nanoparticles induces histamine secretion in mast cells

<p>Abstract</p> <p>Background</p> <p>Histamine released from mast cells, through complex interactions involving the binding of IgE to FcεRI receptors and the subsequent intracellular Ca²⁺signaling, can mediate many allergic/inflammatory responses. The possibility of titanium dioxide nanoparticles (TiO₂NPs), a nanomaterial pervasively used in nanotechnology and pharmaceutical industries, to directly induce histamine secretion without prior allergen sensitization has remained uncertain.</p> <p>Results</p> <p>TiO₂NP exposure increased both histamine secretion and cytosolic Ca²⁺concentration ([Ca²⁺]_C) in a dose dependent manner in rat RBL-2H3 mast cells. The increase in intracellular Ca²⁺levels resulted primarily from an extracellular Ca²⁺influx via membrane L-type Ca²⁺channels. Unspecific Ca²⁺entry via TiO₂NP-instigated membrane disruption was demonstrated with the intracellular leakage of a fluorescent calcein dye. Oxidative stress induced by TiO₂NPs also contributed to cytosolic Ca²⁺signaling. The PLC-IP₃-IP₃receptor pathways and endoplasmic reticulum (ER) were responsible for the sustained elevation of [Ca²⁺]_Cand histamine secretion.</p> <p>Conclusion</p> <p>Our data suggests that systemic circulation of NPs may prompt histamine release at different locales causing abnormal inflammatory diseases. This study provides a novel mechanistic link between environmental TiO₂NP exposure and allergen-independent histamine release that can exacerbate manifestations of multiple allergic responses.</p

Spleen artery embolization increases the success of nonoperative management following blunt splenic injury

AbstractBackgroundSpleen artery embolization (SAE) may increase the success rate of nonoperative management (NOM). The present study investigated the clinical outcome after the installation of SAE in the management of blunt splenic injury.MethodsA retrospective review of hospital records was performed to enroll patients with blunt injury of the spleen. Demographic data and information about the injury severity score, organ injury scale, hospitalization days, management and final outcomes were evaluated. Patients were separated into early and late groups according to the year that SAE was selectively used (2003–2004 and 2005–2008).ResultsSix of eleven (55%) patients in the early group were successfully managed without surgery for blunt splenic injury, whereas all of the 38 patients (100%) in the late group were successfully managed without surgery. Eleven patients (11 of 38; 28.9%) received SAE in the late group. The rate of NOM increased from 55% in the early group to 100% in the late group (p < 0.001). Both early and late groups had similar injury severity score, length of hospitalization, blood transfusion, and complications, and there was no mortality.ConclusionPerformance of SAE for the patients with blunt splenic injury could increase the successful rate of NOM significantly and safely. An algorithm including the angioembolization might be beneficial in the management of patients with blunt spleen trauma