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Goose astrovirus (GAstV), the major causative agent of visceral and joint gout in goslings, is a novel pathogen greatly threatening waterfowl industry. Importantly, the horizontal and vertical transmissibility of GAstV posed a great challenge for disease prevention and control. Given the absence of commercial vaccine, restricting vertical transmission and protecting susceptible goslings must be a priority. Although many detection methods have been established, there is no serological method to detect GAstV-specific antibody, greatly limiting inspection and elimination of infected breeding bird. In this study, the B-cell epitopes of GAstV capsid protein were predicted, and its core antigenic advantage domain (shCAP) was expressed and purified. After authenticating the antigenicity, the recombinant shCAP protein was taken as the coating antigen, and an easily accessible indirect enzyme-linked immunosorbent assay (ELISA) was established to detect GAstV-specific antibody. The working conditions, including antigen concentration, serum dilution and incubation time, blocking buffer concentration, and color developing time, were gradually optimized by checkerboard titration. The cut-off OD

Influenza viruses have been posing a great threat to public health and animal industry. The developed vaccines have been widely used to reduce the risk of potential pandemic; however, the ongoing antigenic drift makes influenza virus escape from host immune response and hampers vaccine efficacy. Until now, the genetic basis of antigenic variation remains largely unknown. In this study, we used A/swine/Guangxi/18/2011 (GX/18) and A/swine/Guangdong/104/2013 (GD/104) as models to explore the molecular determinant for antigenic variation of Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses (SIVs), and found that the GD/104 virus exhibited 32∼64-fold lower antigenic cross-reactivity with antibodies against GX/18 virus. Therefore, we generated polyclonal antibodies against GX/18 or GD/104 virus and a monoclonal antibody (mAb), named mAb102-95, targeted to the hemagglutinin (HA) protein of GX/18 virus, and found that a single amino acid substitution at position 158 in HA protein substantially altered the antigenicity of virus. The reactivity of GX/18 virus containing G158E mutation with the mAb102-95 decreased 8-fold than that of the parental strain. Contrarily, the reactivity of GD/104 virus bearing E158G mutation with the mAb102-95 increased by 32 times as compared with that of the parental virus. Structural analysis showed that the amino acid mutation from G to E was accompanied with the R group changing from -H to -(CH2 )2 -COOH. The induced steric effect and increased hydrophilicity of HA protein surface probably jointly contributed to the antigenic drift of EA H1N1 SIVs. Our study provides experimental evidence that G158E mutation in HA protein affects the antigenic property of EA H1N1 SIVs, and widens our horizon on the antigenic drift of influenza virus. This article is protected by copyright. All rights reserved.

Research on neural style transfer and domain translation has clearly demonstrated the ability of deep learning algorithms to manipulate images based on their artistic style. The idea of image translation has been applied to the task of music-style transfer and to the timbre transfer of musical instrument recordings; however, the results have not been ideal. Generally, the task of instrument timbre transfer depends on the ability to extract a separated manipulable instrument timbre feature. However, as the distinction between a musical note and its timbre is often not sufficiently clear, generated samples by current timbre transfer models usually contain irrelevant waveforms. Here, we propose a method of timbre transfer, for musical instrument sounds, capable of converting one instrument sound to another while preserving note information (duration, pitch, rhythm, etc.). The multichannel attention-guided mechanism is used to enable timbre transfer between spectrograms, enhancing the ability of the model guidance generator to capture the most distinguishable components (harmonic components) in the process. The proposed model uses a Markov discriminator to optimize the generator, enabling it to accurately learn a spectrogram’s higher-order feature. Experimental results demonstrate that the proposed instrument timbre transfer model effectively captures the harmonic components in the target domain and produces explicit high-frequency details.

This paper discusses coordinated excitation and UPFC control to improve power system transient stability. The power system is linearized through direct feedback linearization technique. Robust approach is employed to deal with the uncertainties caused by parameter variations and the inclusion of UPFC controller. Only local measurements are required for designing the excitation controller. The series branch of UPFC is designed to damp the power oscillation during transient period. The shunt branch aims at maintaining bus voltage. The performance of the controllers is tested on a single-machine infinite-bus (SMIB) power system. Simulation results show that both of the series and shunt branch of UPFC help improve transient stability.

This paper discusses a nonlinear controller design for Static Var Compensator (SVC) to improve power system voltage stability. A third-order nonlinear dynamical description for the SVC system is developed. Direct feedback linearization (DFL) technique is employed to design a nonlinear controller. The effectiveness of the controller on voltage stability enhancement is studied on a three-bus power system through time simulation and bifurcation analysis. The results show that the collapse time is put off and the subcritical Hopf bifurcation is greatly affected by the controller. The performance of the controller is further compared with that of the conventional capacitor switching. It is found that in some cases the conventional control scheme cannot prevent voltage collapse while the nonlinear SVC control can stabilize the system. The results show that the proposed controller is effective in voltage stability enhancement.

This paper discusses voltage stability enhancement by a nonlinear Static Var Compensator (SVC) controller. The proposed controller is designed through direct feedback linearization (DFL) technique. The effectiveness of the controller on voltage stability enhancement is studied on a three-machine nine-bus power system. It is found that voltage stability region is expanded significantly by the nonlinear SVC control.