The experimental studies on flow-induced vibrations(FIV) reduction of two side-by-side flexible cylinders inclined at 45° by using the helical strakes were carried out in a towing tank. The main aim of the experi...The experimental studies on flow-induced vibrations(FIV) reduction of two side-by-side flexible cylinders inclined at 45° by using the helical strakes were carried out in a towing tank. The main aim of the experiment is to check whether the helical strakes with a pitch of 17.5 D and a height of 0.25 D, which is considered as the most effective vibration suppression device for the isolated cylinder undergoing vortex-shedding, still perform very well to reduce FIV of two inclined flexible cylinders in a side-by-side arrangement. The vibration of two identical inclined cylinders with a mass ratio of 1.90 and an aspect ratio of 350 was tested in the experiment. The center-to-center distance between the two cylinders was 3.0 D. The uniform flow was simulated by towing the cylinder models along the tank.The towing velocity varied from 0.05 to 1.0 m/s with an interval of 0.05 m/s. The maximum Reynolds number can be up to 1.6×104. Three cases were experimentally studied in this paper, including two side-by-side inclined smooth cylinders, only one smooth cylinder fitted with helical strakes in the two side-by-side inclined cylinders system and both two cylinders attached with helical strakes. The variations of displacement amplitude, dominant frequency, FIV suppression efficiency and dominant mode for the two side-by-side inclined cylinders with reduced velocity were shown and discussed.展开更多
Infections produced by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), two of the most prevalent pathogens in cats, range from passing unnoticed to presenting a wide variety of clinical signs. Di...Infections produced by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), two of the most prevalent pathogens in cats, range from passing unnoticed to presenting a wide variety of clinical signs. Different epidemiological, clinical, hematological and virological parameters were analyzed in 78 FIV- and/or FeLV-infected cats. FeLV-infected (FeLV+) cats were considerably younger than FIV-infected (FIV+) cats, and in general were seen to have a more severe disease than FIV+ cats. Around one third of the cats presented anemia, and neutropenia was also frequently observed. Though a higher percentage of FIV+ than FeLV+ cats had altered leukocyte counts, FeLV+ cats had altered counts of both neutrophils and lymphocytes more frequently than FIV+, which usually presented only either altered neutrophils or lymphocyte counts. Virological markers were only detected in FeLV+cats, either as mono- or dual-infection, and correlated with the severity of the disease, but not in FIV+ cats. In conclusion, these results suggest that FeLV affects more blood cell types and provokes death of affected animals at a much earlier age than FIV and that the severity of the disease seemed to depend on the viral status of the cat.展开更多
The envelope protein （Env） of lentiviruses such as HIV, SIV, FIV and EIAV is larger than that of other retroviruses. The Chinese EIAV attenuated vaccine is based on Env and has helped to successfully control this vi...The envelope protein （Env） of lentiviruses such as HIV, SIV, FIV and EIAV is larger than that of other retroviruses. The Chinese EIAV attenuated vaccine is based on Env and has helped to successfully control this virus, demonstrating that envelope is crucial for vaccine. We compared Env variation of the four kinds of lentiviruses. Phylogenetic analysis showed that the evolutionary relationship of Env between HIV and SIV was the closest and they appeared to descend from a common ancestor, and the relationship of HIV and EIAV was the furthest. EIAV had the shortest Env length and the least number of potential N-linked glyeosylation sites （PNGS） as well as glyeosylation density compared to various immunodefieiency viruses. However, HIV had the longest Env length and the most PNGS. Moreover, the alignment of HIV and SIV showed that PNGS were primarily distributed within extraeellular membrane protein gp120 rather than transmembrane gp41. It implies that the size difference among these viruses is associated with a lentivirus specific function and also the diversity of env. There arc low levels of modification of glycosylation sites of Env and selection of optimal protective epitopes might be useful for development of an effective vaccine against HIV/AIDS.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51479135,51679167 and51379144)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51621092)the Natural Science Foundation of Tianjin(Grant Nos.15JCQNJC43900 and 15JCQNJC07700)
文摘The experimental studies on flow-induced vibrations(FIV) reduction of two side-by-side flexible cylinders inclined at 45° by using the helical strakes were carried out in a towing tank. The main aim of the experiment is to check whether the helical strakes with a pitch of 17.5 D and a height of 0.25 D, which is considered as the most effective vibration suppression device for the isolated cylinder undergoing vortex-shedding, still perform very well to reduce FIV of two inclined flexible cylinders in a side-by-side arrangement. The vibration of two identical inclined cylinders with a mass ratio of 1.90 and an aspect ratio of 350 was tested in the experiment. The center-to-center distance between the two cylinders was 3.0 D. The uniform flow was simulated by towing the cylinder models along the tank.The towing velocity varied from 0.05 to 1.0 m/s with an interval of 0.05 m/s. The maximum Reynolds number can be up to 1.6×104. Three cases were experimentally studied in this paper, including two side-by-side inclined smooth cylinders, only one smooth cylinder fitted with helical strakes in the two side-by-side inclined cylinders system and both two cylinders attached with helical strakes. The variations of displacement amplitude, dominant frequency, FIV suppression efficiency and dominant mode for the two side-by-side inclined cylinders with reduced velocity were shown and discussed.
文摘Infections produced by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), two of the most prevalent pathogens in cats, range from passing unnoticed to presenting a wide variety of clinical signs. Different epidemiological, clinical, hematological and virological parameters were analyzed in 78 FIV- and/or FeLV-infected cats. FeLV-infected (FeLV+) cats were considerably younger than FIV-infected (FIV+) cats, and in general were seen to have a more severe disease than FIV+ cats. Around one third of the cats presented anemia, and neutropenia was also frequently observed. Though a higher percentage of FIV+ than FeLV+ cats had altered leukocyte counts, FeLV+ cats had altered counts of both neutrophils and lymphocytes more frequently than FIV+, which usually presented only either altered neutrophils or lymphocyte counts. Virological markers were only detected in FeLV+cats, either as mono- or dual-infection, and correlated with the severity of the disease, but not in FIV+ cats. In conclusion, these results suggest that FeLV affects more blood cell types and provokes death of affected animals at a much earlier age than FIV and that the severity of the disease seemed to depend on the viral status of the cat.
基金Natural Science Foundation of China(30970162)Tianjin Municipal Science and Technology Foundation(08ZCGHHZ01800)
文摘The envelope protein （Env） of lentiviruses such as HIV, SIV, FIV and EIAV is larger than that of other retroviruses. The Chinese EIAV attenuated vaccine is based on Env and has helped to successfully control this virus, demonstrating that envelope is crucial for vaccine. We compared Env variation of the four kinds of lentiviruses. Phylogenetic analysis showed that the evolutionary relationship of Env between HIV and SIV was the closest and they appeared to descend from a common ancestor, and the relationship of HIV and EIAV was the furthest. EIAV had the shortest Env length and the least number of potential N-linked glyeosylation sites （PNGS） as well as glyeosylation density compared to various immunodefieiency viruses. However, HIV had the longest Env length and the most PNGS. Moreover, the alignment of HIV and SIV showed that PNGS were primarily distributed within extraeellular membrane protein gp120 rather than transmembrane gp41. It implies that the size difference among these viruses is associated with a lentivirus specific function and also the diversity of env. There arc low levels of modification of glycosylation sites of Env and selection of optimal protective epitopes might be useful for development of an effective vaccine against HIV/AIDS.
