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Wang M.-H.,South China Agricultural University | Liang Y.,South China Agricultural University | Liang Y.,South China Collaborative Innovation Center for Poultry Disease Control and Product Safety | Liu F.-M.,South China Agricultural University | Luo X.-N.,Sun Yat Sen University
Ruan Jian Xue Bao/Journal of Software

Dealing with factors such as overlap, blurs from quickly moving and severe deformation, accurate and stable object tracking has become a critical challenge in compute vision field. First, in this paper, superpixels are used as middle level visual clue to describe the components of object/background with the color histograms of components as their features. The initial appearance model is proposed by clustering the features of a component library. The locality and flexibility of components representations allow the appearance model to describe object/background much more accurately. Then, the Bayesian filter model is used to compute the initial state of target region, and an algorithm is proposed to check and deal with the disturbance introduced by similar objects to avoid drift and obtain more robust tracking result. Finally, to reduce the influences of deformation, overlap and blurs to better preserve the features of object, an online appearance model update algorithm is developed based on the complementary set of the features of components library to enable the appearance model to reflect the real-time variation of object/background by the changes of components. Many experiments on video sequences with different tracking challenges (totally about 12 sequences) show that, compared with the existing object tracking methods, the proposed tracking algorithm results in less error of center position and more successful frame, and therefore can track an object more accurately, stably and effectively. © Copyright 2015, Institute of Software, the Chinese Academy of Sciences. All rights reserved. Source

Zhang X.,South China Agricultural University | Zhang X.,Key Laboratory of Chicken Genetics | Wu B.,South China Agricultural University | Wu B.,Key Laboratory of Chicken Genetics | And 13 more authors.

Background: Chicken anemia virus (CAV) is an immunosuppressive virus that causes chicken infectious anemia (CIA) which is a highly contagious avian disease. CAV causes major economic losses in the poultry industry worldwide. The current CAV vaccine is a live attenuated strain administered in the drinking water that risks horizontal infection of other chickens. The purpose of this study was to develop a novel vaccine against CAV that can be administered safely using a highly pathogenic isolate inactivated with β-propiolactone hydrolysis that would protect chicks from CAV. Methods: Hens were vaccinated twice intramuscularly with a novel CAV GD-G-12 inactivated vaccine and the humoral immune responses of the hens and offspring were monitored by ELISA. A heterologous intramuscular challenge using the CAV strain GD-E-12 was conducted in the chicks hatched from vaccinated or unvaccinated hens. Results: The vaccine strain, GD-G-12, was shown to be highly pathogenic prior to inactivation evidenced by thymic atrophy and bleeding, and weight loss. The inactivated vaccine was considered safe and showed no signs of pathogenicity. High titers of CAV specific antibodies were detected in the vaccinated hens and in their chicks, indicating vertical transfer of maternal antibodies. Furthermore, the chicks hatched from vaccinated hens were resistant to a heterologous CAV challenge and showed no signs of weight loss and thymic atrophy and bleeding. Conclusion: Our studies are proof of principle that inactivated GD-G-12 might be a novel vaccine candidate to prevent CAV infection, and highlight the utility of using an inactivated virus for this vaccine. © 2015 Elsevier Ltd. Source

Dai Z.,South China Agricultural University | Ji J.,Nanyang Normal University | Yan Y.,South China Agricultural University | Lin W.,South China Agricultural University | And 18 more authors.

Subgroup J avian leukosis virus (ALV-J) causes a neoplastic disease in infected chickens. Differential expression patterns of microRNAs (miRNAs) are closely related to the formation and growth of tumors. (1) Background: This study was undertaken to understand how miRNAs might be related to tumor growth during ALV-J infection. We chose to characterize the effects of miR-221 and miR-222 on cell proliferation, migration, and apoptosis based on previous microarray data. (2) Methods: In vivo, the expression levels of miR-221 and miR-222 were significantly increased in the liver of ALV-J infected chickens (p < 0.01). Over-expression of gga-miR-221 and gga-miR-222 promoted the proliferation, migration, and growth of DF-1 cells, and decreased the expression of BCL-2 modifying factor (BMF) making cells more resistant to apoptosis. (3) Results: Our results suggest that gga-miR-221 and gga-miR-222 may be tumour formation relevant gene in chicken that promote proliferation, migration, and growth of cancer cells, and inhibit apoptosis. BMF expression was significantly reduced in vivo 70 days after ALV-J infection. They may also play a pivotal role in tumorigenesis during ALV-J infection. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source

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