The LightGBM-based classification algorithm for Chinese characters speech imagery BCI system.

Brain-computer interface (BCI) can obtain text information by decoding language induced electroencephalogram (EEG) signals, so as to restore communication ability for patients with language impairment. At present, the BCI system based on speech imagery of Chinese characters has the problem of low accuracy of features classification. In this paper, the light gradient boosting machine (LightGBM) is adopted to recognize Chinese characters and solve the above problems. Firstly, the Db4 wavelet basis function is selected to decompose the EEG signals in six-layer of full frequency band, and the correlation features of Chinese characters speech imagery with high time resolution and high frequency resolution are extracted. Secondly, the two core algorithms of LightGBM, gradient-based one-side sampling and exclusive feature bundling, are used to classify the extracted features. Finally, we verify that classification performance of LightGBM is more accurate and applicable than the traditional classifiers according to the statistical analysis methods. We evaluate the proposed method through contrast experiment. The experimental results show that the average classification accuracy of the subjects' silent reading of Chinese characters "(left)", "(one)" and simultaneous silent reading is improved by 5.24%, 4.90% and 12.44% respectively.

Images Reconstruction from Functional Magnetic Resonance Imaging Patterns Based on the Improved Deep Generative Multiview Model.

Reconstructing visual stimulus images from the brain activity signals is an important research task in the field of brain decoding. Many methods of reconstructing visual stimulus images mainly focus on how to use deep learning to classify the brain activities measured by functional magnetic resonance imaging or identify visual stimulus images. Accurate reconstruction of visual stimulus images by using deep learning still remains challenging. This paper proposes an improved deep generative multiview model to further promote the accuracy of reconstructing visual stimulus images. Firstly, an encoder based on residual-in-residual dense blocks is designed to fit the deep and multiview visual features of human natural state, and extract the features of visual stimulus images. Secondly, the structure of original decoder is extended to a deeper network in the deep generative multiview model, which makes the features obtained by each deconvolution layer more distinguishable. Finally, we configure the parameters of the optimizer and compare the performance of various optimizers under different parameter values, and then the one with the best performance is chosen and adopted to the whole model. The performance evaluations conducted on two publicly available datasets demonstrate that the improved model has more accurate reconstruction effectiveness than the original deep generative multiview model.

Hsf1 promotes hematopoietic stem cell fitness and proteostasis in response to ex vivo culture stress and aging.

Maintaining proteostasis is key to resisting stress and promoting healthy aging. Proteostasis is necessary to preserve stem cell function, but little is known about the mechanisms that regulate proteostasis during stress in stem cells, and whether disruptions of proteostasis contribute to stem cell aging is largely unexplored. We determined that ex-vivo-cultured mouse and human hematopoietic stem cells (HSCs) rapidly increase protein synthesis. This challenge to HSC proteostasis was associated with nuclear accumulation of Hsf1, and deletion of Hsf1 impaired HSC maintenance ex vivo. Strikingly, supplementing cultures with small molecules that enhance Hsf1 activation partially suppressed protein synthesis, rebalanced proteostasis, and supported retention of HSC serial reconstituting activity. Although Hsf1 was dispensable for young adult HSCs in vivo, Hsf1 deficiency increased protein synthesis and impaired the reconstituting activity of middle-aged HSCs. Hsf1 thus promotes proteostasis and the regenerative activity of HSCs in response to culture stress and aging.

Effect of fed-batch and chemostat cultivation processes of C. glutamicum CP for L-leucine production.

Most of the current industrial processes for L-leucine production are based on fermentation, usually in fed-batch operation mode. Although the culture technology has advanced in recent decades, the process still has significant drawbacks. To solve these problems, we investigated the effects of chemostat culture conditions on the production of L-leucine by Corynebacterium glutamicum CP. The dilution rate, the nitrogen source, and the carbon-nitrogen ratio of the medium were optimized. With the addition of ammonium acetate to the chemostat medium, the initial C/N ratio was adjusted to 57.6, and the L-leucine titer reached the highest level at the optimal dilution rate of 0.04 h-1. Compared with fed-batch culture, the L-leucine titer was reduced (from 53.0 to 24.8 g L-1), but the yield from glucose was increased by 10.0% (from 0.30 to 0.33 mol mol-1) and productivity was increased by 58.3% (from 1.2 to 1.9 g L-1 h-1). Moreover, the titer of the by-product L-alanine was significantly reduced (from 8.9 to 0.8 g L-1). In addition, gene expression levels and activity of key enzymes in the synthesis of L-leucine and L-alanine were analyzed to explain the difference of production performance between chemostat culture and fed-batch culture. The results indicate that chemostat culture has great potential to increase the industrial production of L-leucine compared to current fed-batch approaches.

[Effects of Adding Straw and Biochar with Equal Carbon Content on Soil Respiration and Microbial Biomass Carbon and Nitrogen].

In order to investigate the response of soil respiration, soil microbial biomass carbon and nitrogen, and hydrothermal factors to the addition of biochar and straw, we used an LI-8100 soil carbon flux meter (LI-COR, Lincoln, USA) to study changes in soil respiration and microbial biomass under four treatments:conventional fertilization (CK), conventional fertilization +2.25t·hm-2 biochar-C (T1), conventional fertilizer +2.25t·hm-2 straw-C (T2), and conventional fertilizer +2.25t·hm-2 (biochar-C+straw-C), biochar-C:straw-C=1:1 (T3). The results showed that:① the addition of biochar and straw significantly increased the soil respiration rate and total CO2 emissions, with the largest increase in T3 and the smallest increase in T1. The effect of T1 on soil respiration was promoted in the early stage and later inhibited. ② The microbial biomass carbon and nitrogen and the number of functional bacterial colonies increased significantly with biochar and straw amendments. T1 had a significant promotion effect on nitrogen-fixing bacteria, while T2 had no significant effect on the number of fungi, and T3 showed a positive interaction effect. Soil respiration rates were significantly and positively related to soil microbial biomass carbon and nitrogen as well as to the number of bacteria and actinomycetes. ③ The 5 cm soil temperature of T3 significantly increased by 4.53%. The soil respiration rate and soil temperature showed a significant exponential correlation. To sum up, adding straw and biochar with equal carbon content can significantly increase the soil respiration rate and microbial biomass, and the interaction effect between biochar and straw is positive. Compared with that of the straw treatments, the application of biochar can reduce carbon mineralization to a certain extent, and the effect of carbon sequestration is better.

Magnetic critical behavior of the van der Waals Fe5GeTe2 crystal with near room temperature ferromagnetism.

The van der Waals ferromagnet Fe5GeTe2 has a Curie temperature TC of about 270 K, which is tunable through controlling the Fe deficiency content and can even reach above room temperature. To achieve insights into its ferromagnetic exchange that gives the high TC, the critical behavior has been investigated by measuring the magnetization in Fe5GeTe2 crystal around the ferromagnetic ordering temperature. The analysis of the measured magnetization by using various techniques harmonically reached to a set of reliable critical exponents with TC = 273.7 K, ß = 0.3457 ± 0.001, γ = 1.40617 ± 0.003, and δ = 5.021 ± 0.001. By comparing these critical exponents with those predicted by various models, it seems that the magnetic properties of Fe5GeTe2 could be interpreted by a three-dimensional magnetic exchange with the exchange distance decaying as J(r) ≈ r-4.916, close to that of a three-dimensional Heisenberg model with long-range magnetic coupling.

Analysis of Dynamic Global Transcriptional Atlas Reveals Common Regulatory Networks of Hormones and Photosynthesis Across Nicotiana Varieties in Response to Long-Term Drought.

Land plants evolve drought acclimation. Existing knowledge of gene regulation mainly comes from short-term drought treatment. However, common regulatory mechanism shared by multiple varieties under long-term drought is little explored. Here we investigated changes in physiology, hormones and transcriptomes in leaves of Nicotiana varieties K326 and Basma Xanthi with/without drought treatment at time courses spanning 1 month. Analyses of deep RNA-Seq data and further full-length Iso-Seq data revealed an atlas of dynamic changes of transcripts, spliced isoforms, gene expression, associated Gene Ontology, and metabolism pathways. Fewer differentially expressed genes (DEGs) were induced by drought in high tolerance variety than susceptible variety. Comparison among seven hormone signal pathways identified that genes in both abscisic acid and auxin signaling pathways were highly induced although specific genes were depended on the variety. Common hormone regulatory network analysis revealed that genes encoding clade A protein phosphatase 2C gene (PP2C) in abscisic acid pathway was the pivotal hub. Expressional regulation in photosynthesis was also common and variety specific. We conclude that long-term drought inducing gene regulatory networks of hormones and photosynthesis are variety dependent, and PP2C is the center of the common hormone regulatory network. Thus, this study improves our understanding of gene regulatory network in drought response.

Selenium Modulates the Level of Auxin to Alleviate the Toxicity of Cadmium in Tobacco.

Cadmium (Cd) is an environmental pollutant that potentially threatens human health worldwide. Developing approaches for efficiently treating environmental Cd is a priority. Selenium (Se) plays important role in the protection of plants against various abiotic stresses, including heavy metals. Previous research has shown that Se can alleviate Cd toxicity, but the molecular mechanism is still not clear. In this study, we explore the function of auxin and phosphate (P) in tobacco (Nicotiana tabacum), with particular focus on their interaction with Se and Cd. Under Cd stress conditions, low Se (10 µM) significantly increased the biomass and antioxidant capacity of tobacco plants and reduced uptake of Cd. We also measured the auxin concentration and expression of auxin-relative genes in tobacco and found that plants treated with low Se (10 µM) had higher auxin concentrations at different Cd supply levels (0 µM, 20 µM, 50 µM) compared with no Se treatment, probably due to increased expression of auxin synthesis genes and auxin efflux carriers. Overexpression of a high affinity phosphate transporter NtPT2 enhanced the tolerance of tobacco to Cd stress, possibly by increasing the total P and Se content and decreasing Cd accumulation compared to that in the wild type (WT). Our results show that there is an interactive mechanism among P, Se, Cd, and auxin that affects plant growth and may provide a new approach for relieving Cd toxicity in plants.

Single-dose CRISPR-Cas9 therapy extends lifespan of mice with Hutchinson-Gilford progeria syndrome.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare lethal genetic disorder characterized by symptoms reminiscent of accelerated aging. The major underlying genetic cause is a substitution mutation in the gene coding for lamin A, causing the production of a toxic isoform called progerin. Here we show that reduction of lamin A/progerin by a single-dose systemic administration of adeno-associated virus-delivered CRISPR-Cas9 components suppresses HGPS in a mouse model.

Rapid detection of six phosphodiesterase type 5 enzyme inhibitors in healthcare products using thin-layer chromatography and surface enhanced Raman spectroscopy combined with BP neural network.

A novel facile method for the detection of the phosphodiesterase type 5 enzyme inhibitors added illegally into health products was established using thin-layer chromatography and surface enhanced Raman spectroscopy combined with BP neural network. When the detection conditions were optimized in detail, a repetitive adding procedure of silver colloids with the total amount keeping constant was used to improve the enhancement effect of surface enhanced Raman spectroscopy. According to the main Raman peaks and the retention factor of analyte, the data predictive model was established. Under the optimized experimental conditions, this method was successful to apply to detect the artificially produced model samples, and the limit of detection less than 5 mg/kg was obtained. Based on the excellent sensitivity of this method, the real samples have been detected accurately and the detection results were confirmed by high-performance liquid chromatography. In addition, the developed method was suitable for the detection of other adulterants, especially those that have similar chromatographic or spectroscopic behaviors.

NtNAC-R1, a novel NAC transcription factor gene in tobacco roots, responds to mechanical damage of shoot meristem.

Topping is the important agronomic measure for flue-cured tobacco, and results in increase of the nicotine content in top leaves. Nicotine content is one of the vitals factors for the quality of tobacco leaves. Nicotine is exclusively synthesized in tobacco roots, and then transported to the leaves through the xylem. To investigate the molecular mechanism of increase in nicotine biosynthesis ability following topping, some responses of tobacco roots to topping were analyzed, and the role of NtNAC-R1 in regulating nicotine synthesis and the development of roots was discussed. The electronic cloning technique combined with RT-PCR was successfully used to clone NtNAC-R1 from tobacco roots. The number of lateral root and nicotine contents in tobacco roots increased following topping. Although spraying MeJA on leaves had no effects on the root phenotype, the nicotine contents and the expression of PMT increased markedly. The miR164 was down-regulated, and NtNAC-R1 was up-regulated in tobacco roots after topping. PMT and ODC were down-regulated in transgenic tobacco with antisense NtNAC-R1, and PMT was up-regulated in transgenic tobacco with over-expressed NtNAC-R1. In conclusion, topping can induce the decrease of miR164 and the increase of IAA content in roots, which up-regulate the expression of NtNAC-R1, resulting in the increase of lateral roots and nicotine contents. Meanwhile, topping is a mechanical wounding which can induce JA signal, and JA can enhance nicotine biosynthesis in tobacco roots. So the increase of nicotine biosynthesis ability would be related to cross-talking of JA and auxin signaling pathway after topping.