2019, 8(3):1-9. DOI: 10.12146/j.issn.2095-3135.20190226001
Abstract:Tracking virus infection pathway in cells is of great significance for understanding the viral infection mechanism, and the successful labeling on viruses is the key to achieve viruses tracking. In this study, we proposed the in situ bioorthogonal strategy based on the bioorthogonal chemistry and metabolic engineering for overcoming defects of traditional virus labeling methods. Azido motifs were incorporated into virions through cell metabolism with lipid/amino acid/monosaccharide azide derivatives, and the modified virions were in situ labeled with dibenzocyclooctyne-functionalized fluorescent probes through the bioorthogonal reaction. The results show that viruses incorporated with azide motifs could be quickly and effectively captured by fluorescent probes to achieve viruses in situ labeling. Significantly, the in situ bioorthogonal labeling strategy is a general method for enveloped and non-enveloped viruses labeling with simple operations.
2019, 8(3):10-18. DOI: 10.12146/j.issn.2095-3135.20190305001
Abstract:Bacteriophages are one of the most common microorganisms on the earth, and are potential biocontrol agents for multidrug-resistant bacteria. Aeromonas salmonicide is a major bacterial pathogen in aquaculture. It can be responsible for furunculosis, which is a ubiquitous disease in aquaculture operation and featured by high mortality and morbidity, causing significant economic loss of aquaculture. In this study, Aeromonas salmonicida MF663675.1 was used as host to isolate bacteriophage from the sewage of a seafood market in Shenzhen, China. A novel lytic phage Asfd-1 was isolated and purified by double-layer agar plate. The morphological characteristics were observed by transmission electron microscope (TEM). The plaque characteristics were observed as well. The whole genome and phylogenetic analysis of phage Asfd-1 were carried out by bioinformatics methods. The results show that plaque of the phage was round and transparent with size of about 1 mm in diameter. TEM shows that Asfd-1 has an isometric, elongated and icosahedral head of 100 nm in diameter by 71 nm in width and a 51 nm contracted tail. Comparative genomics analysis indicates that Asfd-1 has a double-stranded DNA of 168 962 bp in length, and the content ratio of guanine and cytosine is 41.53%. Asfd-1 genome encodes 263 open reading frames and 16 tRNA genes, indicating that Asfd-1 is not totally dependent on host cell transcription machinery. Combined with TEM and phylogenetic analysis, it proposes that Asfd-1 belongs a new member of the T4 virus, Myoviridae family, Caudovirales order. Based on its microbiological traits, phage Asfd-1 is a promising agent that can be used for controlling Aeromonas salmonicida infection.
2019, 8(3):19-30. DOI: 10.12146/j.issn.2095-3135.20190301001
Abstract:Dorsomedial hypothalamic nucleus (DMH) is an important component of autonomic nervous system, which has extensive connections with limbic system. DMH may participates in the regulation of negative emotions, such as anxiety and fear. However, the cellular mechanisms are still unknown. In this study, elevated plus maze and open filed tests were performed, and a bidirectional effect of optogenetic modulation on behaviors was found. Activating the DMH glutamatergic or gamma-aminobutyric acid (GABAergic) neurons leading to the anxiety-like behavior and increasing of heart rate, while optical inhibition significantly suppressed the anxiety-like behavior and decreased heart rate. These findings may provide new targets for clinical therapy for neuropsychiatric disorders.
2019, 8(3):31-41. DOI: 10.12146/j.issn.2095-3135.20181113001
Abstract:Cryptographic card is a kind of encryption device located in the physical layer of the network security platform. It provides several encryption and decryption algorithms, digital signature, and other cryptographic operation services for application systems. Considering the security of cloud computing, the cryptographic card needs to be high speed and achieve high concurrency through virtualization technology. The challenge for the cards as input/output (I/O) devices is how to achieve high I/O performance and share I/O devices in the case of virtualization effectively. At present, the development of I/O virtualization technology is lagging behind, which affects the overall performance of the virtual machine. Based on this, this paper realizes the software virtualization cryptographic card by using field-programmable gate array and the single root I/O virtualization technology. In practical applications, a virtualized cryptographic card is built into the server through the peripheral component interconnect express bus, which has high performance and can be shared by many users. The results show that this technology has broad applications in the field of information security.
2019, 8(3):42-54. DOI: 10.12146/j.issn.2095-3135.20190225001
Abstract:Recently, automated neural network architecture design (neural architecture search) has yielded many significant achievements. Improving the prediction accuracy of the neural network is the primary goal. However, besides the prediction accuracy, other types of cost including memory consumption, inference time, and training time are also very important when implementing the neural network. In practice, such types of cost are often bounded by thresholds. Current neural architecture search method with budgeted cost constraints can only optimize some specific types of the cost. In this paper, we propose budgeted efficient neural architecture search (B-ENAS) to optimize more types of cost. The experimental results on the well-adopted CIFAR10 dataset show that B-ENAS can learn convolutional neural network architectures with high accuracy under different cost constraints.
2019, 8(3):55-65. DOI: 10.12146/j.issn.2095-3135.20180325001
Abstract:Traffic prediction is of great significance for intelligent capacity planning and task scheduling. However, large-scale e-commerce cluster traffics have various uncertain emergencies, such as online promotion activities and user aggregation requests. These uncertain events may cause many bursts in the time series, which poses a huge challenge to traffic prediction. At the same time, capacity prediction should be robust to uncertainty. That is, it should cope well with possible future situations and ensure cluster stability, rather than shrink the capacity strictly based on the prediction. For the traffic scenarios of large-scale distributed e-commerce clusters and the requirements of dynamic capacity planning, this paper proposes a real-time load forecasting framework with uncertainty estimates. The framework is based on multivariate long short-term memory auto-encoder and Bayesian theory, which can provide accurate uncertainty interval estimation while performing flow deterministic prediction.
2019, 8(3):66-75. DOI: 10.12146/j.issn.2095-3135.20180912002
Abstract:RV (Rotor Vector) reducer is an important transmission device in the industrial robot system. It is usually composed by an involute planetary gear and a cycloidal pin wheel. In this paper, a novel analysis method of pins was proposed based on theoretical force analysis with the consideration of real wearing condition. By simulating the pins with the improved analysis method, shear force and bending stress on the pins can be calculated. To reduce the effect caused by shear force and bending stress, the short pins were used to replace traditional long pins. Experimental results show that, the usage of short pins not only can eliminate shear force and bending stress, but also decreases the occurrence of slippage during meshing, and that makes the RV reducer with higher reliability and longer service life.
2019, 8(3):76-81. DOI: 10.12146/j.issn.2095-3135.20180820001
Abstract:Subject to the space of installation and working condition, tilt-mounted asynchronous motor is prone to excessive vibration. In this paper, an experimental device is designed to investigate the vibration characteristics of tilt-mounted asynchronous motor by considering its structural characteristics. The stiffness characteristics of asynchronous motor system with vibration damping pad are analyzed firstly. Finite element analysis is used to calculate stiffness coefficient of vibration damping pad with different thickness. In real experiments, different thickness of rubber vibration isolation cushion are used for the vibration test and analysis. And the experimental results show that, the resonance speed of asynchronous motor decreases with the reduction of vibration damping pad stiffness, while the tilt angle of 5° is adopted. This conclusion can provide guidance for the design and installation of tilt-mounted asynchronous motor and shock absorber.