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41.
Ahmed S Abdel-Moneim Ahmad E Abdel-Ghany Salama AS Shany 《Journal of biomedical science》2010,17(1):25
Background
The highly pathogenic H5N1 is a major avian pathogen that crosses species barriers and seriously affects humans as well as some mammals. It mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences. 相似文献42.
We study the SIS and SIRI epidemic models discussing different approaches to compute the thresholds that determine the appearance
of an epidemic disease. The stochastic SIS model is a well known mathematical model, studied in several contexts. Here, we
present recursively derivations of the dynamic equations for all the moments and we derive the stationary states of the state
variables using the moment closure method. We observe that the steady states give a good approximation of the quasi-stationary
states of the SIS model. We present the relation between the SIS stochastic model and the contact process introducing creation
and annihilation operators. For the spatial stochastic epidemic reinfection model SIRI, where susceptibles S can become infected
I, then recover and remain only partial immune against reinfection R, we present the phase transition lines using the mean
field and the pair approximation for the moments. We use a scaling argument that allow us to determine analytically an explicit
formula for the phase transition lines in pair approximation. 相似文献
43.
N Stollenwerk S van Noort J Martins M Aguiar F Hilker A Pinto G Gomes 《Journal of biological dynamics》2010,4(6):634-649
Recently, the notion of a reinfection threshold in epidemiological models of only partial immunity has been debated in the literature. We present a rigorous analysis of a model of reinfection which shows a clear threshold behaviour at the parameter point where the reinfection threshold was originally described. Furthermore, we demonstrate that this threshold is the mean field version of a transition in corresponding spatial models of immunization. The reinfection threshold corresponds to the transition between annular growth of an epidemics spreading into a susceptible area leaving recovered behind and compact growth of a susceptible-infected-susceptible region growing into a susceptible area. This transition between annular growth and compact growth was described in the physics literature long before the reinfection threshold debate broke out in the theoretical biology literature. 相似文献
44.
Jessica AB van Nies Rute B Marques Stella Trompet Zuzana de Jong Fina AS Kurreeman Rene EM Toes J Wouter Jukema Tom WJ Huizinga Annette HM van der Helm-van Mil 《Arthritis research & therapy》2010,12(2):R38
Introduction
Recently an association between a genetic variation in TRAF1/C5 and mortality from sepsis or cancer was found in rheumatoid arthritis (RA). The most prevalent cause of death, cardiovascular disease, may have been missed in that study, since patients were enrolled at an advanced disease stage. Therefore, we used an inception cohort of RA patients to investigate the association between TRAF1/C5 and cardiovascular mortality, and replicate the findings on all-cause mortality. As TRAF1/C5 associated mortality may not be restricted to RA, we also studied a large cohort of non-RA patients. 相似文献45.
Gabriela Ludwig Lucas M. Aguiar João M. D. Miranda Gustavo M. Teixeira Walfrido K. Svoboda Luciano S. Malanski Marcos M. Shiozawa Carmen L. S. Hilst Italmar T. Navarro Fernando C. Passos 《International journal of primatology》2007,28(1):39-46
Researchers consider predation rates by terrestrial animals to be lower in the case of arboreal primates, particularly among
large-bodied species. We recorded the consumption of black-and-gold howlers (Alouatta caraya) by cougars (Puma concolor) as evidence of predation on an island of the upper Paraná River. We collected and processed fecal samples of the felid in
2004 and 2005. We identified items in the laboratory by comparison with museum specimens. We considered each species in a
fecal sample as a single occurrence. Based on analysis of the cuticle scale pattern, we identified the felid as cougar. Howlers
occurred in 4 out of the 8 fecal samples (40% of the occurrences). In addition to howlers, we also recorded 5 occurrences
of agouti (Dasyprocta azarae; 50%) and a small unidentified sigmodontine rodent (10%). The abundance of howlers and the low forest canopy in a successional
vegetation might have facilitated the predation of the large primates by a primarily terrestrial predator. The versatility
of cougars is corroborated by the consumption of prey species that were abundant in the region and that were available in
different forest strata, such as howlers and agoutis. 相似文献
46.
Corte AC Svoboda WK Navarro IT Freire RL Malanski LS Shiozawa MM Ludwig G Aguiar LM Passos FC Maron A Camargo ZP Itano EN Ono MA 《Mycopathologia》2007,164(5):225-228
The aim of this study was to evaluate the seroprevalence of Paracoccidioides brasiliensis infection in wild New World monkeys (Cebus sp. and Alouatta caraya). A total of 93 animals (Cebus sp., n = 68 and Alouatta caraya, n = 25) were captured in the Paraná River basin, Paraná State, Brazil and the serum samples were analyzed by ELISA and immunodiffusion
using P. brasiliensis gp43 and exoantigen as antigens, respectively. The seropositivity observed by ELISA was 44.1% and 60% for Cebus sp. and A. caraya, respectively, while by immunodiffusion test Cebus sp. showed positivity of 2.9% only. No significant difference was observed in relation to age and sex. This is the first
report of paracoccidioidomycosis in wild capuchin monkeys and in wild-black and golden-howler monkeys. The high positivity
to P. brasiliensis infection in both species evaluated in our study and the positivity by immunodiffusion test in Cebus sp. suggest that natural disease may be occurring in wild monkeys living in paracoccidioidomycosis endemic areas. 相似文献
47.
Wasps and bees are important components of flower visitor guilds in the Neotropical region. The abundance of social wasps and bees, collected during flower visits, was used to calculate niche breadth and niche overlap indices, in order to characterize the utilization of the floral resources by those insects. Samples were taken monthly, for 13 months (156h), by two collectors which captured the specimens on flowers using entomological nets, while walking along a way in an area of caatinga at Itatim, State of Bahia, Brazil. Wasps and bees heavily visited a few sources of floral resources, but the most visited plants by each group were different, and few plant species were important for both groups, resulting in low niche overlap between bees and wasps. The niche overlap among wasp species was generally higher than among bee species. The general overlap, which takes into consideration all species together was low (< 30%). 相似文献
48.
Fonseca Bárbara Medeiros Câmara Paulo Eduardo Aguiar Saraiva Ogaki Mayara Baptistucci Pinto Otávio Henrique Bezerra Lirio Juan Manuel Coria Silvia H. Vieira Rosemary Carvalho-Silva Micheline Amorim Eduardo Toledo Convey Peter Rosa Luiz Henrique 《Molecular biology reports》2022,49(1):179-188
Molecular Biology Reports - Vega Island is located off the eastern tip of the Antarctic Peninsula (Maritime Antarctica), in the Weddell Sea. In this study, we used metabarcoding to investigate... 相似文献
49.
Hakim Bouamar Daifeng Jiang Long Wang An-Ping Lin Manoela Ortega Ricardo C. T. Aguiar 《Molecular and cellular biology》2015,35(8):1329-1340
In biological processes, the balance between positive and negative inputs is critical for an effective physiological response and to prevent disease. A case in point is the germinal center (GC) reaction, wherein high mutational and proliferation rates are accompanied by an obligatory suppression of the DNA repair machinery. Understandably, when the GC reaction goes awry, loss of immune cells or lymphoid cancer ensues. Here, we detail the functional interactions that make microRNA 155 (miR-155) a key part of this process. Upon antigen exposure, miR-155−/− mature B cells displayed significantly higher double-strand DNA break (DSB) accumulation and p53 activation than their miR-155+/+ counterparts. Using B cell-specific knockdown strategies, we confirmed the role of the miR-155 target Aicda (activation-induced cytidine deaminase) in this process and, in combination with a gain-of-function model, unveiled a previously unappreciated role for Socs1 in directly modulating p53 activity and the DNA damage response in B lymphocytes. Thus, miR-155 controls the outcome of the GC reaction by modulating its initiation (Aicda) and termination (Socs1/p53 response), suggesting a mechanism to explain the quantitative defect in germinal center B cells found in mice lacking or overexpressing this miRNA. 相似文献
50.
Eric?Roberto?Guimar?es?Rocha Aguiar Roenick Proveti Olmo Simona Paro Flavia Viana Ferreira Isaque?Jo?o?da?Silva de?Faria Yaovi?Mathias?Honore Todjro Francisco Pereira Lobo Erna Geessien Kroon Carine Meignin Derek Gatherer Jean-Luc Imler Jo?o Trindade Marques 《Nucleic acids research》2015,43(13):6191-6206
Virus surveillance in vector insects is potentially of great benefit to public health. Large-scale sequencing of small and long RNAs has previously been used to detect viruses, but without any formal comparison of different strategies. Furthermore, the identification of viral sequences largely depends on similarity searches against reference databases. Here, we developed a sequence-independent strategy based on virus-derived small RNAs produced by the host response, such as the RNA interference pathway. In insects, we compared sequences of small and long RNAs, demonstrating that viral sequences are enriched in the small RNA fraction. We also noted that the small RNA size profile is a unique signature for each virus and can be used to identify novel viral sequences without known relatives in reference databases. Using this strategy, we characterized six novel viruses in the viromes of laboratory fruit flies and wild populations of two insect vectors: mosquitoes and sandflies. We also show that the small RNA profile could be used to infer viral tropism for ovaries among other aspects of virus biology. Additionally, our results suggest that virus detection utilizing small RNAs can also be applied to vertebrates, although not as efficiently as to plants and insects. 相似文献