Sleep healthcare at home is a new research topic that needs to develop new sensors, hardware and algorithms with the consideration of convenience, portability and accuracy. Monitoring sleep behaviors by visual sensors represents one new unobtrusive approach to facilitating sleep monitoring and benefits sleep quality. The challenge of video surveillance for sleep behavior analysis is that we have to tackle bad image illumination issue and large pose variations during sleeping. This paper proposes a robust method for sleep pose analysis with human joints model. The method first tackles the illumination variation issue of infrared videos to improve the image quality and help better feature extraction. Image matching by keypoint features is proposed to detect and track the positions of human joints and build a human model robust to occlusion. Sleep poses are then inferred from joint positions by probabilistic reasoning in order to tolerate occluded joints. Experiments are conducted on the video polysomnography data recorded in sleep laboratory. Sleep pose experiments are given to examine the accuracy of joint detection and tacking, and the accuracy of sleep poses. High accuracy of the experiments demonstrates the validity of the proposed method.

BackgroundStreptococcus pneumoniae is a respiratory pathogen causing severe lung infection that may lead to complications such as bacteremia. Current polysaccharide vaccines have limited serotype coverage and therefore cannot provide maximal and long-term protection. Global efforts are being made to develop a conserved protein vaccine candidate. PrtA, a pneumococcal surface protein, was identified by screening a pneumococcal genomic expression library using convalescent patient serum. The prtA gene is prevalent and conserved among S. pneumoniae strains. Its protective efficacy, however, has not been described. Mucosal immunization could sensitize both local and systemic immunity, which would be an ideal scenario for preventing S. pneumoniae infection.MethodsWe immunized BALB/c mice intranasally with a combination of a PrtA fragment (amino acids 144–1041) and Th17 potentiated adjuvant, curdlan. We then measured the T-cell and antibody responses. The protective efficacy conferred to the immunized mice was further evaluated using a murine model of acute pneumococcal pneumonia and pneumococcal bacteremia.ResultsThere was a profound antigen-specific IL-17A and IFN-γ response in PrtA-immunized mice compared with that of adjuvant control group. Even though PrtA-specific IgG and IgA titer in sera was elevated in immunized mice, only a moderate IgA response was observed in the bronchoalveolar lavage fluid. The PrtA-immunized antisera facilitated the activated murine macrophage, RAW264.7, to opsonophagocytose S. pneumoniae D39 strain; however, PrtA-specific immunoglobulins bound to pneumococcal surfaces with a limited potency. Finally, PrtA-induced immune reactions failed to protect mice against S. pneumoniae-induced acute pneumonia and bacterial propagation through the blood.ConclusionsImmunization with recombinant PrtA combined with curdlan produced antigen-specific antibodies and elicited IL-17A response. However, it failed to protect the mice against S. pneumoniae-induced infection.Electronic supplementary materialThe online version of this article (10.1186/s12931-018-0895-8) contains supplementary material, which is available to authorized users.

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