Disentangled Feature Learning for Real-Time Neural Speech Coding

Recently end-to-end neural audio/speech coding has shown its great potential to outperform traditional signal analysis based audio codecs. This is mostly achieved by following the VQ-VAE paradigm where blind features are learned, vector-quantized and coded. In this paper, instead of blind end-to-end learning, we propose to learn disentangled features for real-time neural speech coding. Specifically, more global-like speaker identity and local content features are learned with disentanglement to represent speech. Such a compact feature decomposition not only achieves better coding efficiency by exploiting bit allocation among different features but also provides the flexibility to do audio editing in embedding space, such as voice conversion in real-time communications. Both subjective and objective results demonstrate its coding efficiency and we find that the learned disentangled features show comparable performance on any-to-any voice conversion with modern self-supervised speech representation learning models with far less parameters and low latency, showing the potential of our neural coding framework.Comment: Submitted to ICASSP202

Interactive Speech and Noise Modeling for Speech Enhancement

Speech enhancement is challenging because of the diversity of background noise types. Most of the existing methods are focused on modelling the speech rather than the noise. In this paper, we propose a novel idea to model speech and noise simultaneously in a two-branch convolutional neural network, namely SN-Net. In SN-Net, the two branches predict speech and noise, respectively. Instead of information fusion only at the final output layer, interaction modules are introduced at several intermediate feature domains between the two branches to benefit each other. Such an interaction can leverage features learned from one branch to counteract the undesired part and restore the missing component of the other and thus enhance their discrimination capabilities. We also design a feature extraction module, namely residual-convolution-and-attention (RA), to capture the correlations along temporal and frequency dimensions for both the speech and the noises. Evaluations on public datasets show that the interaction module plays a key role in simultaneous modeling and the SN-Net outperforms the state-of-the-art by a large margin on various evaluation metrics. The proposed SN-Net also shows superior performance for speaker separation.Comment: AAAI 2021 (Accepted

Chemical-free Extraxtion of Cotton Stalk Bark Fibers by Steam Flash Explosion

Cotton stalk bark fibers (CSBF) were extracted by steam flash explosion, completed within 0.09 s, and the extracted fibers were compared with those obtained by conventional alkaline treatment. Results indicate that the optimum steam pressure was 2.5 MP a when steaming time was set to 2 min for extracting CSBF. Under the optimized conditions, the obtained CBSF had a cellulose content of 72%, length of 48 mm, fineness of 45 dtex, crystallinity index of 68, moisture regain of 8%, water rention of 98%, and tensile strength of 2.4 cN/dtex, which were similar to results obtained by conventional alkaline treatment. Compared with bark of cotton stalks, CSBF had lower moisture regain and water retention, and higher onset decomposition temperature. The results sow that moderate steam flash explosion is a chemical-free, quick, and effective method for exploring the industrial applications of bark of cotton stalks as natural cellulose fibers

Metabolic profiling reveals key metabolites regulating adventitious root formation in ancient Platycladus orientalis cuttings

Platycladus orientalis, a common horticultural tree species, has an extremely long life span and forms a graceful canopy. Its branches, leaves, and cones have been used in traditional Chinese medicine. However, difficulty in rooting is the main limiting factor for the conservation of germplasm resources. This study shows that the rooting rates and root numbers of cuttings were significantly reduced in ancient P. orientalis donors compared to 5-year-old P. orientalis donors. The contents of differentially accumulated metabolites (DAMs) in phenylpropanoid (caffeic acid and coniferyl alcohol) and flavonoid biosynthesis (cinnamoyl-CoA and isoliquiritigenin) pathways increased significantly in cuttings propagated from ancient P. orientalis donors compared to 5-year-old P. orientalis donors during adventitious root (AR) formation. These DAMs may prevent the ancient P. orientalis cuttings from rooting, and gradual lignification of callus was one of the main reasons for the failed rooting of ancient P. orientalis cuttings. The rooting rates of ancient P. orientalis cuttings were improved by wounding the callus to identify wounding-induced rooting-promoting metabolites. After wounding, the contents of DAMs in zeatin (5′-methylthioadenosine, cis-zeatin-O-glucoside, and adenine) and aminoacyl-tRNA biosynthesis (l-glutamine, l-histidine, l-isoleucine, l-leucine, and l-arginine) pathways increased, which might promote cell division and provided energy for the rooting process. The findings of our study suggest that breaking down the lignification of callus via wounding can eventually improve the rooting rates of ancient P. orientalis cuttings, which provides a new solution for cuttings of other difficult-to-root horticultural and woody plants

Natural Inflation, Planck Scale Physics and Oscillating Primordial Spectrum

In the ``natural inflation'' model, the inflaton potential is periodic. We show that Planck scale physics may induce corrections to the inflaton potential, which is also periodic with a greater frequency. Such high frequency corrections produce oscillating features in the primordial fluctuation power spectrum, which are not entirely excluded by the current observations and may be detectable in high precision data of cosmic microwave background (CMB) anisotropy and large scale structure (LSS) observations.Comment: 20 pages, 11 figures. To appear in Int J Mod. Phys.

Valproic acid inhibits Aβ production, neuritic plaque formation, and behavioral deficits in Alzheimer's disease mouse models

Neuritic plaques in the brains are one of the pathological hallmarks of Alzheimer's disease (AD). Amyloid β-protein (Aβ), the central component of neuritic plaques, is derived from β-amyloid precursor protein (APP) after β- and γ-secretase cleavage. The molecular mechanism underlying the pathogenesis of AD is not yet well defined, and there has been no effective treatment for AD. Valproic acid (VPA) is one of the most widely used anticonvulsant and mood-stabilizing agents for treating epilepsy and bipolar disorder. We found that VPA decreased Aβ production by inhibiting GSK-3β–mediated γ-secretase cleavage of APP both in vitro and in vivo. VPA treatment significantly reduced neuritic plaque formation and improved memory deficits in transgenic AD model mice. We also found that early application of VPA was important for alleviating memory deficits of AD model mice. Our study suggests that VPA may be beneficial in the prevention and treatment of AD

Transcriptome differences between 20- and 3,000-year-old Platycladus orientalis reveal that ROS are involved in senescence regulation

Background: Platycladus orientalis has an extremely long life span of several thousands of years, attracting great interests in the mechanisms involved in such successful senescence regulation and resistance at physiological and molecular levels. Results: The levels of reactive oxygen species (ROS) were higher in 3,000-year-old than in 20-year-old P. orientalis, and the activities of GR and GSH demonstrated the same trend. We produced and analyzed massive sequence information from pooled samples of P. orientalis through transcriptome sequencing, which generated 51,664 unigenes with an average length of 475 bp. We then used RNA-seq analysis to obtain a high-resolution age\u2013course profile of gene expression in 20- and 3,000-year-old P. orientalis individuals. Totally, 106 differentially expressed genes were obtained, of which 47 genes were downregulated and 59 upregulated in the old tree. These genes were involved in transcription factors, hormone-related responses, ROS scavengers, senescence-related responses, stress response, and defense and possibly play crucial roles in tackling various stresses in the 3,000-year-old P. orientalis during its life time. The expression patterns of genes related to ROS homeostasis further indicated that the high ability of ROS scavenging could be helpful for the 3,000-year-old P. orientalis to resist senescence. Conclusions: This study provides a foundation for the elucidation of senescence resistance through molecular studies and the discovery of useful genes in P. orientalis