Investigation of artifacts by mapping SAR in thermoacoustic imaging

Microwave-induced thermoacoustic imaging(MI-TAI)remains one of the focus of attention among biomedical imaging modalities over the last decade.However,the transmission and dis-tribution of microwave inside bio-tissues are complicated,thus result in severe artifacts.In this study,to reveal the underlying mechanisms of artifacts,we deeply investigate the distribution of specific absorption rate(SAR)inside tissue-mimicking phantoms with varied morphological features using both mathematical simulations and corresponding experiments.Our simulated results,which are confirmed by the associated experimental results,show that the SAR distri-bution highly depends on the geometries of the imaging targets and the polarizing features of the microwave.In addition,we propose the potential mechanisms including Mie-scattering,Fabry-Perot-feature,small curvature effect to interpret the diffraction effect in different scenarios,which may provide basic guidance to predict and distinguish the artifacts for TAI in both fundamental and clinical studies.

Imaging Fast Cellular Uptake of Polymer Dots via Receptor‑Mediated Endocytosis

During the past decade,semiconducting polymer dots(Pdots)have been prevailing in the family of fluorescent probes due to its high photon budget,excellent photo stability,and good biocompatibility.In this study,holo-Transferrin human(Tf)was utilized to covalently couple with Pdots for a highly efficient endocytosis process through transferrin receptors(TfRs)mediated internalization.As a result,the endocytosis efficiency of Tf-conjugated Pdots in HeLa cells dramatically increased as compared to that of unconjugated Pdots in the same condition.This acute increment demonstrates that holo-Transferrin molecules are of great capability for intracellular delivery of Pdots to TfRs overexpressed cells.The transportation route of Tf-conjugated Pdots is quite different from the uptake mechanism of unconjugated Pdots via nonspecific endocytic trafficking pathway.Considering the overexpression of TfRs in various cancer cells,Tf-conjugated Pdots hold potential to function as a nanocarrier for efficient drug delivery in cancer diagnostics and therapy.

Entry,Descent,and Landing of China’s Tianwen-1 Mars Mission

1.Main Text Launched into orbit on July 23,2020,China’s first Mars mission Tianwen-1 has implemented the key missions of“near-Mars capture and brake,”“entry,descent,and landing(EDL),”and“rover leaving the landing platform”successively in nearly one year.The three major tasks of“orbiting around Mars,”“Mars surface landing,”and“exploration and detection”have also been accomplished.At present,the Zhurong Mars rover is performing exploration and detection tasks as planned.For Tianwen-1,China’s first probe landing on an extraterrestrial planet to carry out such elaborate tasks,EDL is the risk point of the Mars mission that is mostly difficult to accomplish.