Severe toothache can be caused by dental pulp inflammation. The ionotropic purinergic receptor family (P2X) is reported to mediate nociception in primary afferent neurons. This study aims to investigate the involvement of P2X receptors in the sensitization of the trigeminal ganglion (TG) caused by dental pulp inflammation. Lipopolysaccharides were unilaterally applied to the pulp of the upper molar of the rat to induce dental pulp inflammation. Increased expression of c-fos, a marker of neuronal activity, was induced in V1-V2 division, indicating the activation of TG neurons. The expressions of P2X2, P2X3, and P2X5 were also increased in the V1-V2 division of TG, primarily in small-sized and medium-sized neurons. Markers of glutamatergic afferents, VGluT1, and GABAergic afferents, GAD67, were induced by lipopolysaccharides and coexpressed with P2X in small-sized TG neurons. The present findings suggest that the P2X2, P2X3, and P2X5 receptors are upregulated as part of the sensitization produced by dental pulp inflammation.

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Homeobox A9 (HOXA9), the expression of which is promoted by mixed lineage leukemia 1 (MLL1) and WD-40 repeat protein 5 (WDR5), is a homeodomain-containing transcription factor that plays an essential role in regulating stem cell activity. HOXA9 has been found to inhibit skeletal muscle regeneration and delay recovery after muscle wounding in aged mice, but little is known about its role in denervated/reinnervated muscles. We performed detailed time-dependent expression analyses of HOXA9 and its promoters, MLL1 and WDR5, in rat gastrocnemius muscles after the following three types of sciatic nerve surgeries: nerve transection (denervation), end-to-end repair (repair), and sham operation (sham). Then, the specific mechanisms of HOXA9 were detected in vitro by transfecting primary satellite cells with empty pIRES2-DsRed2, pIRES2-DsRed2-HOXA9, empty pPLK/GFP-Puro, and pPLK/GFP-Puro-HOXA9 small hairpin RNA (shRNA) plasmids. We found, for the first time, that HOXA9 protein expression simultaneously increased with increasing denervated muscle atrophy severity and that upregulated MLL1 and WDR5 expression was partly associated with denervation. Indeed, in vitro experiments revealed that HOXA9 inhibited myogenic differentiation, affected the best known atrophic signaling pathways, and promoted apoptosis but did not eliminate the differentiation potential of primary satellite cells. HOXA9 may promote denervated muscle atrophy by regulating the activity of satellite cells.

The failure mechanism of red phosphorus retardant PA66 electrical connectors is investigated.

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Vertical axis wind turbines (VAWT) have been valued in recent years for their low manufacturing cost, structural simplicity and convenience of applications in urban settings. Despite their advantages, VAWTs have several drawbacks including low power coefficient, poor self-starting ability, negative torque and the associated cyclic stress at certain azimuth angles. Using pitch control ideas, our research is aimed at solving the above problems. In this study, a small-scale Giromill VAWT using three NACA-0015 airfoils with a cord length of 0.09 m and a wind turbine radius of 0.6 m is investigated. During each rotation, the angle of attack depends on the wind velocity, angular velocity and current azimuth angle for each turbine blade. Negative torques at certain angles are attributed to the inherent unsteady aerodynamic behavior at high angles of attack. Without optimal pitch control, the Double-Multiple Streamtube (DMS) model predicts negative torques at certain azimuth angles and very low power coefficients for tip speed ratios below 2.5. The unfavorable negative torques are eliminated using an optimal pitch control strategy, which maximizes the tangential force coefficients and thus the torque coefficients by iterations of all possible relative angles of attack for various tip speed ratios. As a result, the power coefficient is significantly improved especially at low tip speed ratios in the range of zero to three (λ = 0 – 3). Blade pitch control can also solve the self-starting problem and reduce the vibration of vertical axis wind turbines.

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