Search

• A kind of optimized VMD algorithm was proposed, which could select the value of K adaptively. • The LMS algorithm was used to reduce the noise of lowest frequency component obtained by the optimal VMD algorithm. • The second harmonic curve obtained by the proposed algorithm was matched best compared with the results of the other two traditional algorithms. • The proposed algorithm had important application value in the noise reduction field of TDLAS system. Currently, traditional variational modal decomposition (VMD) algorithm requires manual selection of the number of decomposition layers K according to the decomposition results, which increases the complexity of the system. What's more, the noise reduction effect of traditional VMD algorithm needs to be further improved for low frequency signal. A kind of optimized VMD algorithm was proposed, which could select the value of K adaptively. The simulated signal containing noise of TDLAS was processed using optimized VMD algorithm, and further denoised by the least mean square (LMS) algorithm. The result shown that the proposed algorithm not only improved reconstruction effect for absorption signal, but also enhanced the measurement accuracy of TDLAS compared with regular noise reduction algorithms. [ABSTRACT FROM AUTHOR]

With the rapid development of cancer-targeted nanotechnology, a variety of nanoparticle-based drug delivery systems have clinically been employed in cancer therapy. However, multidrug resistance significantly impacts the therapeutic efficacy. Physical non-drug therapy has emerged as a new and promising strategy. This study aimed to determine whether novel folate-nanobubbles (F-NBs), combined with therapeutic ultrasound (US), could act as a safe and effective physical targeted cancer therapy. Using folate-conjugated N-palmitoyl chitosan (F-PLCS), we developed novel F-NBs and characterised their physicochemical properties, internalization mechanism, targeting ability, therapeutic effects, and killing mechanism. The results showed that the novel F-NBs selectively accumulated in FR-positive endothelial cells and tumour cells via FR coupled with clathrin- and caveolin-mediated endocytosis in vitro and in vivo . In addition, the F-NBs killed target cells by an intracellular explosion under US irradiation. Hoechst/PI staining demonstrated that apoptosis and necrosis accounted for a large proportion of cell death in vivo . F-NBs combined with US therapy significantly inhibited tumour growth and improved the overall survival of tumour-bearing mice. Under US irradiation, the novel F-NBs selectively killed FR-positive tumour cells in vitro and in vivo via intracellular explosion and therefore is a promising alternative for targeted cancer treatment. [ABSTRACT FROM AUTHOR]