pH/enzyme dual sensitive and nucleus-targeting dendrimer nanoparticles to enhance the antitumour activity of doxorubicin.

Direct delivery of drugs into the nucleus is a promising nanotechnology therapy, since the nucleus is one of the most important organelles controlling cell proliferation and apoptosis. Here, we report a nucleus-targeting nanocarrier for nuclear drug delivery using a pH/enzyme dual sensitive strategy. The specific ligand PGM (PKKKRKV-GFLG-Mp), composed of nuclear localization sequence (PKKKRKV), enzyme-sensitive tetrapeptide (Gly-Phe-Leu-Gly, GFLG), and pH-sensitive molecules morpholine (Mp), was modified on poly (amidoamine) (PAMAM) by maleimide active polyethylene glycol ester (NHS-PEG-MAL) to form PAMAM-PEG-PGM. Doxorubicin (DOX) was loaded into the cavity of PAMAM to prepare DOX/PAMAM-PEG-PGM. In vitro release study suggested DOX release from DOX/PAMAM-PEG-PGM nanoparticles followed pH and enzyme-triggered manner. In vitro studies showed DOX/PAMAM-PEG-PGM nanoparticles could not only promote cell internalization through the charge switching of morpholine, but also achieve nuclear internalization by the mediation of composite formed by NLS and importin α/ß receptor. Further, employing H22 tumour-bearing BALB/c mice as a model, the systemic distribution and anticancer effects of nanoparticles were studied in vivo. The results indicated the nanoparticles could preferentially accumulate in the tumour site in vivo, and the tumour inhibition rate was 88.47%. In short, the nanoparticles developed could be promising in application to nucleus-targeting therapy to enhance antitumour activity.

Novel Fiber-Optic Ring Acoustic Emission Sensor.

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

Detonation Velocity Measurement with Chirped Fiber Bragg Grating.

Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are pasted both on the surface and in the center of the explosive cylinder. The length of CFBG sensors is measured via the hot-tip probe method. The light intensity reflected from the CFBG sensors attached to the explosive is transformed to voltage, and the voltage-time is then measured with the oscilloscope. According to the five experiments results, the relative standard uncertainty of detonation velocity is below 1%.

Bearing-based localization for leader-follower formation control.

The observability of the leader robot system and the leader-follower formation control are studied. First, the nonlinear observability is studied for when the leader robot observes landmarks. Second, the system is shown to be completely observable when the leader robot observes two different landmarks. When the leader robot system is observable, multi-robots can rapidly form and maintain a formation based on the bearing-only information that the follower robots observe from the leader robot. Finally, simulations confirm the effectiveness of the proposed formation control.