A target guided subband filter for acoustic event detection in noisy environments using wavelet packets

This paper deals with acoustic event detection (AED), such as screams, gunshots, and explosions, in noisy environments. The main aim is to improve the detection performance under adverse conditions with a very low signal-to-noise ratio (SNR). A novel filtering method combined with an energy detector is presented. The wavelet packet transform (WPT) is first used for time-frequency representation of the acoustic signals. The proposed filter in the wavelet packet domain then uses a priori knowledge of the target event and an estimate of noise features to selectively suppress the background noise. It is in fact a content-aware band-pass filter which can automatically pass the frequency bands that are more significant in the target than in the noise. Theoretical analysis shows that the proposed filtering method is capable of enhancing the target content while suppressing the background noise for signals with a low SNR. A condition to increase the probability of correct detection is also obtained. Experiments have been carried out on a large dataset of acoustic events that are contaminated by different types of environmental noise and white noise with varying SNRs. Results show that the proposed method is more robust and better adapted to noise than ordinary energy detectors, and it can work even with an SNR as low as -15 dB. A practical system for real time processing and multi-target detection is also proposed in this work

Dual roles of protein tyrosine phosphatase kappa in coordinating angiogenesis induced by pro-angiogenic factors

A potential role may be played by receptor-type protein tyrosine phosphatase kappa (PTPRK) in angiogenesis due to its critical function in coordinating intracellular signal transduction from various receptors reliant on tyrosine phosphorylation. In the present study, we investigated the involvement of PTPRK in the cellular functions of vascular endothelial cells (HECV) and its role in angiogenesis using in vitro assays and a PTPRK knockdown vascular endothelial cell model. PTPRK knockdown in HECV cells (HECVPTPRKkd) resulted in a decrease of cell proliferation and cell-matrix adhesion; however, increased cell spreading and motility were seen. Reduced focal adhesion kinase (FAK) and paxillin protein levels were seen in the PTPRK knockdown cells which may contribute to the inhibitory effect on adhesion. HECVPTPRKkd cells were more responsive to the treatment of fibroblast growth factor (FGF) in their migration compared with the untreated control and cells treated with VEGF. Moreover, elevated c-Src and Akt1 were seen in the PTPRK knockdown cells. The FGF-promoted cell migration was remarkably suppressed by an addition of PLCγ inhibitor compared with other small inhibitors. Knockdown of PTPRK suppressed the ability of HECV cells to form tubules and also impaired the tubule formation that was induced by FGF and conditioned medium of cancer cells. Taken together, it suggests that PTPRK plays dual roles in coordinating angiogenesis. It plays a positive role in cell proliferation, adhesion and tubule formation, but suppresses cell migration, in particular, the FGF-promoted migration. PTPRK bears potential to be targeted for the prevention of tumour associated angiogenesis

The ultra-low-frequency shear modes of 2-4 layer graphenes observed in their scroll structures at edges

The in-plane shear modes between neighbor-layers of 2-4 layer graphenes (LGs) and the corresponding graphene scrolls rolled up by 2-4LGs were investigated by Raman scattering. In contrast to that just one shear mode was observed in 3-4LGs, all the shear modes of 3-4LGs were observed in 3-4 layer scrolls (LSs), whose frequencies agree well with the theoretical predication by both a force-constant model and a linear chain model. In comparison to the broad width (about 12cm$^{-1}$) for the G band in graphite, all the shear modes exhibit an intrinsic line width of about 1.0 cm$^{-1}$. The local electronic structures dependent on the local staking configurations enhance the intensity of the shear modes in corresponding 2-4LSs zones, which makes it possible to observe all the shear modes. It provides a direct evidence that how the band structures of FLGs can be sensitive to local staking configurations. This result can be extended to n layer graphene (n > 4) for the understanding of the basic phonon properties of multi-layer graphenes. This observation of all-scale shear modes can be foreseen in other 2D materials with similar scroll structures.Comment: 14 pages, 5 figure

MLN4924 (Pevonedistat), a protein neddylation inhibitor, suppresses proliferation and migration of human clear cell renal cell carcinoma

Neddylation is a post-translational protein modification associated with cancer development. MLN4924 is a neddylation inhibitor currently under investigation in multiple phase I studies on various malignancies, and its clincal name is Pevonedistat. It has been documented that MLN4924 blocks Cullins neddylation and inactivates CRLs and, in turn, triggers cell-cycle arrest, apoptosis, senescence and autophagy in many cancer cells. In this study, we investigated the anti-tumor effect of MLN4924 in human clear cell renal carcinoma (ccRCC). Levels of both Nedd8 activating enzyme E1 and Nedd8- conjugating enzyme E2 were higher in ccRCC tissues and RCC cancer cells than in normal. Moreover, MLN4924 treatment led to rapid inhibition of Cullin1 neddylation and notably suppressed growth and survival as well as migration in a dose-and time-dependent manner. Mechanistic studies revealed that MLN4924 induced the accumulation of a number of CRL substrates, including p21, p27 and Wee1 to trigger DNA damage and induce growth arrest at the G2/M phase. MLN4924 also induced antimigration and anti-invasion by activating E-cadherin and repressing Vimentin. Taken together, this study provides the first evidence that neddylation pathway is overactive in ccRCC and that MLN4924 induces dose-dependent anti-proliferation, anti-migration, anti-invasion in ccRCC cells. The study thus indicates that MLN4924 has potential therapeutic value for the clinical treatment of renal cance