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| 1 | Four residues of propeptide are essential for precursor folding of nattokinase显示文摘Subtilisin propeptide 作为指导先锋合拢的 intramolecular 女伴工作。Nattokinase, subtilisin 家庭的一个成员,当由信号肽, propeptide,和一个 subtilisin 领域组成的一位先锋,和它的合拢的机制尚待被理解,被综合。在这研究,贡献先锋合拢的 nattokinase propeptide 的必要残余是坚定的。删除分析证明在 propeptide 的保存区域为先锋合拢是重要的。单个地点并且多地点 mutagenesis 研究证实了 Tyr10, Gly13, Gly34,和 Gly35 的角色。在期间上演(i) 并且(ii ) 将先锋合拢, Tyr10 和 Gly13 形成 subtilisin 的接口的部分域。当 Gly34 和 Gly35 与将稳定 propeptide 的结构的一个螺旋连接了时。四倍的翼变化, Y10A/G13A/G34A/G35A,为 propeptide 导致了女伴功能的损失。这个工作为先锋经由第二等的结构和运动参数分析合拢显示出 propeptide 的必要残余。 | Yan Jia Xinhua Cao Yu Deng Wei Bao Changyan Tang Hanjing Ding Zhongliang Zheng Guolin Zou | 2014 | Acta Biochimica et Biophysica Sinica2014，46，11： | 4 |
| 2 | Uniform single atomic Cu_(1)-C_(4)sites anchored in graphdiyne for hydroxylation of benzene to phenol显示文摘For single-atom catalysts(SACs),the catalyst supports are not only anchors for single atoms,but also modulators for geometric and electronic structures,which determine their catalytic performance.Selecting an appropriate support to prepare SACs with uniform coordination environments is critical for achieving optimal performance and clarifying the relationship between the structure and the property of SACs.Approaching such a goal is still a significant challenge.Taking advantage of the strong d-πinteraction between Cu atoms and diacetylenic in a graphdiyne(GDY)support,we present an efficient and simple strategy for fabricating Cu single atoms anchored on GDY(Cu_(1)/GDY)with uniform Cu_(1)-C_(4)single sites under mild conditions.The Cu atomic structure was confirmed by combining synchrotron radiation X-ray absorption spectroscopy,X-ray photoele ctron spectroscopy and density functional theory(DFT)calculations.The as-prepared Cu1/GDY exhibits much higher activity than state-of-the-art SACs in direct benzene oxidation to phenol with H_(2)O_(2)reaction,with turnover frequency values of 251 h^(-1)at room temperature and 1889 h^(-1)at 60℃,respectively.Furthermore,even with a high benzene conversion of86%,high phenol sele ctivity(96%)is maintaine d,which can be ascribed to the hydrophobic and oleophyllic surface nature of Cu1/GDY for benzene adsorption and phenol desorption.Both experiments and DFT calculations indicate that Cu_(1)-C_(4)single sites are more effective at activating H_(2)O_(2)to form Cu=O bonds,which are important active intermediates for benzene oxidation to phenol. | Jia Yu Changyan Cao Hongqiang Jin Weiming Chen Qikai Shen Peipei Li Lirong Zheng Feng He Weiguo Song Yuliang Li | 2022 | National Science Review2022，9，9： | 3 |
| 3 | Development of chiral praziquantel analogues as potential drug candidates with activity to juvenile Schistosoma japonicum显示文摘 | Yang Zheng LanLan Dong Changyan Hu Bo Zhao Chunhua Yang Chaoming Xia Dequn Sun | 2014 | Bioorganic & Medicinal Chemistry Letters2014，，17： | 1 |
| 4 | Breaking the activity limitation of iridium single-atom catalyst in hydrogenation of quinoline with synergistic nanoparticles catalysis显示文摘Single-atom catalysts(SACs)with the advantages of homogeneous and heterogeneous catalysts have become a hot-spot in catalysis field.However,for lack of metal–metal bond in SACs,H_(2)has to go through heterolytic dissociation pathway,which has higher barrier than homolytic dissociation pathway,and thus limits the hydrogenation activity of SACs.Herein,we propose and demonstrate through constructing synergistic iridium single atoms and nanoparticles co-existed catalyst(denoted as Ir_(1+NPs)/CMK)to boost the catalytic activity of quinoline hydrogenation.Both experimental and density functional theory calculation results confirm that Ir_(1)single sites activate quinoline,while Ir nanoparticles boost hydrogen dissociation.H atoms generated at Ir nanoparticles migrate to the quinoline bounded Ir_(1)single sites to complete hydrogenation.The Ir_(1+NPs)/CMK catalyst exhibits much higher reactivity with turnover frequency of 7,800 h^(−1)than those counterpart Ir_(1)/CMK and IrNPs/CMK catalysts,and is 20,000 times higher activity of commercial Ir/C benchmark catalyst for hydrogenation of quinoline under the same reaction conditions.This synergistic catalysis strategy between single atoms and nanoparticles provides a solution to further improve the performance of SACs for hydrogenation. | Qikai Shen Hongqiang Jin Peipei Li Xiaohu Yu Lirong Zheng Weiguo Song Changyan Cao | 2022 | Nano Research2022，15，6： | 0 |
| 5 | Comparison of enhancement techniques based on neural networks for attenuated voice signal captured by flexible vibration sensors on throats显示文摘Wearable flexible sensors attached on the neck have been developed to measure the vibration of vocal cords during speech.However,highfrequency attenuation caused by the frequency response of the flexible sensors and absorption of high-frequency sound by the skin are obstacles to the practical application of these sensors in speech capture based on bone conduction.In this paper,speech enhancement techniques for enhancing the intelligibility of sensor signals are developed and compared.Four kinds of speech enhancement algorithms based on a fully connected neural network(FCNN),a long short-term memory(LSTM),a bidirectional long short-term memory(BLSTM),and a convolutional-recurrent neural network(CRNN)are adopted to enhance the sensor signals,and their performance after deployment on four kinds of edge and cloud platforms is also investigated.Experimental results show that the BLSTM performs best in improving speech quality,but is poorest with regard to hardware deployment.It improves short-time objective intelligibility(STOI)by 0.18 to nearly 0.80,which corresponds to a good intelligibility level,but it introduces latency as well as being a large model.The CRNN,which improves STOI to about 0.75,ranks second among the four neural networks.It is also the only model that is able to achieves real-time processing with all four hardware platforms,demonstrating its great potential for deployment on mobile platforms.To the best of our knowledge,this is one of the first trials to systematically and specifically develop processing techniques for bone-conduction speed signals captured by flexible sensors.The results demonstrate the possibility of realizing a wearable lightweight speech collection system based on flexible vibration sensors and real-time speech enhancement to compensate for high-frequency attenuation. | Shenghan Gao Changyan Zheng Yicong Zhao Ziyue Wu Jiao Li Xian Huang | 2022 | Nanotechnology and Precision Engineering2022，5，1： | 0 |
| 6 | Improving the performance of speech waveform synthesis using WaveNet fused with phase information显示文摘Compared with phase spectrum,magnitude spectrum can represent most speech information,hence many speech processing tasks pay much attention on manipulating magnitude spectrum and use the imperfect vocoder parameters or mismatched phase spectrum to synthesize the waveform,which leads to an obvious distortion of speech quality.To address this problem,a modified version of Wave Net model fused with phase information is proposed to synthesize the speech with higher quality.In the Wave Net model,the original or processed phase spectrum of speech and the enhanced magnitude spectrum are concatenated as the condition input,and then the predicted speech waveform is generated directly from this input,which is a kind of fusion feature.The proposed method can realize the effective utilization of the phase information and is verified in two tasks including voice conversion(VC)and bone-conducted speech enhancement(BSE).Two kinds of phase spectrum,the modified group delay(MGD)spectrum and the instantaneous frequency deviation spectrum,are compared comprehensively in the simulation experiments,and the influence of the fusion feature on the bandwidth extension Wave Net model and the teacher-student Wave Net model is also explored.In VC experiments,the A/B test shows the generated speech using the teacher-student Wave Net model is much better than using the STRAIGHT vocoder.In BSE experiments,the results show that,using the bandwidth extension Wave Net model via the feature fused with MGD spectrum,the mean opinion score(MOS)of the enhanced speech increases by 54.3%compared with the original bone-conducted speech.All the results demonstrate that the phase-fused condition input can supplement single magnitude spectrum efficiently and help the Wave Net vocoder achieve promising improvement on the quality of the synthesized speech. | ZHENG Changyan YANG Jibin ZHANG Xiongwei SUN Meng | 2022 | Chinese Journal of Acoustics2022，41，1： | 0 |
| 7 | Monaural speech enhancement using U-net fused with multi-head self-attention显示文摘Under low signal-to-noise ratio(SNR)and burst noise conditions,the speech enhancement effect of existing deep learning network models is not satisfactory.In contrast,humans can exploit the long-term correlation of speech to form an integrated perception of different speech signals.Thus,describing the long-term dependencies of speech can help improve the enhancement performance under low SNR and burst noise conditions.Inspired by this feature,a time domain end-to-end monaural speech enhancement model TU-net that fuses the multi-head self-attention mechanism and U-net deep network is proposed.The TU-net model adopts the codec layer structure of U-net to achieve multi-scale feature fusion.It introduces the dual-path Transformer module using the multi-head self-attention mechanism to calculate the speech mask and better model long-term correlation.The TU-net model is trained with a weighted sum loss function in the time,time-frequency,and perceptual domains.Simulation experiments are carried out and the results show that with maintaining relatively fewer network model parameters,TU-net outperforms other similar monaural enhancement network models in several evaluation metrics such as perceptual evaluation of speech quality(PESQ),short-time objective intelligibility(STOI)and SNR gain under low SNR and burst noise conditions. | FAN Junyi YANG Jibin ZHANG Xiongwei ZHENG Changyan | 2023 | Chinese Journal of Acoustics2023，42，1： | 0 |
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