Underwater Target Localization and Synchronization for a Distributed SIMO Sonar with an Isogradient SSP and Uncertainties in Receiver Locations.

A distributed single-input multiple-output (SIMO) sonar system is composed of a sound source and multiple underwater receivers. It provides an important framework for underwater target localization. However, underwater hostile environments bring more challenges for underwater target localization than terrestrial target localization, such as the difficulties of synchronizing all the underwater receiver clocks, the varying underwater sound speed and the uncertainties of the locations of the underwater receivers. In this paper, we take the sound speed variation, the time synchronization and the uncertainties of the receiver locations into account, and propose the underwater target localization and synchronization (UTLS) algorithm for the distributed SIMO sonar system. In the distributed SIMO sonar system, the receivers are organized in a star topology, where the information fusion is carried out in the central receiver (CR). All the receivers are not synchronized and their positions are known with uncertainties. Moreover, the underwater sound speed is approximately modeled by a depth-dependent sound speed profile (SSP). We evaluate our proposed UTLS algorithm by comparing it with several benchmark algorithms via numerical simulations. The simulation results reveal the superiority of our proposed UTLS algorithm.

Advances in biodegradable nanomaterials for photothermal therapy of cancer.

Photothermal cancer therapy is an alternative to chemotherapy, radiotherapy, and surgery. With the development of nanophotothermal agents, this therapy holds immense potential in clinical translation. However, the toxicity issues derived from the fact that nanomaterials are trapped and retained in the reticuloendothelial systems limit their biomedical application. Developing biodegradable photothermal agents is the most practical route to address these concerns. In addition to the physicochemical properties of nanomaterials, various internal and external stimuli play key roles on nanomaterials uptake, transport, and clearance. In this review, we summarized novel nanoplatforms for photothermal therapy; these nanoplatforms can elicit stimuli-triggered degradation. We focused on the recent innovative designs endowed with biodegradable photothermal agents under different stimuli, including enzyme, pH, and near-infrared (NIR) laser.