, and the third study is described for the first time in this article. These studies reveal how users view the ranked results on a search engine results page (SERP), the relationship between the search result abstracts viewed and those clicked on, and whether gender, search task, or search engine influence these behaviors. In addition, we discuss a key challenge that arose in all three studies that applies to the use of eye tracking in studying online behaviors which is due to the limited support for analyzing scanpaths, or sequences of eye fixations. To meet this challenge, we present a preliminary approach that involves a graphical visualization to compare a path with a group of paths. We conclude by summarizing our findings and discussing future work in further understanding online search behavior with the help of eye tracking.

Yersinia pestis is a Gram-negative bacterium that causes plague. After Y. pestis overcomes the skin barrier, it encounters antigen-presenting cells, such as Langerhans and dendritic cells. They transport the bacteria from the skin to the lymph nodes. However, the molecular mechanisms involved in bacterial transmission are unclear. Langerhans cells express Langerin (CD207), a calcium-dependent (C-type) lectin. Furthermore, Y. pestis possesses exposed core oligosaccharides. In this study, we show that Y. pestis invades Langerhans cells and Langerin-expressing transfectants. However, when the bacterial core oligosaccharides are shielded or truncated, Y. pestis propensity to invade Langerhans- and Langerin-expressing cells decreases. Moreover, the interaction of Y. pestis with Langerin-expressing transfectants is inhibited by purified Langerin, a DC-SIGN-like molecule, an anti-CD207 antibody, purified core oligosaccharides and several oligosaccharides. Furthermore, covering core oligosaccharides reduces the mortality associated with murine infection by adversely affecting the transmission of Y. pestis to lymph nodes. These results demonstrate that direct interaction of core oligosaccharides with Langerin facilitates the invasion of Langerhans cells by Y. pestis. Therefore, Langerin-mediated binding of Y. pestis to antigen-presenting cells may promote its dissemination and infection.

Yersinia pestis, a Gram-negative bacterium and the etiologic agent of plague, has evolved from Yersinia pseudotuberculosis, a cause of a mild enteric disease. However, the molecular and biological mechanisms of how Y. pseudotuberculosis evolved to such a remarkably virulent pathogen, Y. pestis, are not clear. The ability to initiate a rapid bacterial dissemination is a characteristic hallmark of Y. pestis infection. A distinguishing characteristic between the two Yersinia species is that Y. pseudotuberculosis strains possess an O-antigen of lipopolysaccharide (LPS) while Y. pestis has lost the O-antigen during evolution and therefore exposes its core LPS. In this study, we showed that Y. pestis utilizes its core LPS to interact with SIGNR1 (CD209b), a C-type lectin receptor on antigen presenting cells (APCs), leading to bacterial dissemination to lymph nodes, spleen and liver, and the initiation of a systemic infection. We therefore propose that the loss of O-antigen represents a critical step in the evolution of Y. pseudotuberculosis into Y. pestis in terms of hijacking APCs, promoting bacterial dissemination and causing the plague.

Melioidosis is a severe tropical infectious disease caused by the soil-dwelling bacterium Burkholderia pseudomallei, predominantly endemic to Southeast Asia and northern Australia. Between the 1970s and the 1990s, the presence of B. pseudomallei causing melioidosis in humans and other animals was demonstrated in four coastal provinces in southern China: Hainan, Guangdong, Guangxi, and Fujian, although indigenous cases were rare and the disease failed to raise concern amongst local and national health authorities. In recent years, there has been a rise in the number of melioidosis cases witnessed in the region, particularly in Hainan. Meanwhile, although China has established and maintained an effective communicable disease surveillance system, it has not yet been utilized for melioidosis. Thus, the overall incidence, social burden and epidemiological features of the disease in China remain unclear. In this context, we present a comprehensive overview of both historical and current information on melioidosis in Southern China, highlighting the re-emergence of the disease in Hainan. Surveillance and management strategies for melioidosis should be promoted in mainland China, and more research should be conducted to provide further insights into the present situation.

The third plague pandemic originated from Yunnan Province, China in the middle of the 19th century. The last human plague epidemic in Yunnan occurred from 1986–2005. On June 6, 2016, a case of human plague was reported in the Xishuangbanna Prefecture, Yunnan. The patient suffered from primary septicemic plague after exposure to a dead house rat (Rattus flavipectus), which has been identified as the main plague reservoir in the local epizootic area. Moreover, a retrospective investigation identified another bubonic plague case in this area. Based on these data, human plague reemerged after a silent period of ten years. In this study, three molecular typing methods, including a clustered regularly interspaced short palindromic repeats (CRISPR) analysis, different region analysis (DFR), and multiple-locus variable number of tandem repeats analysis (MLVA), were used to illustrate the molecular characteristics of Yersinia pestis (Y. pestis) strains isolated in Yunnan. The DFR profiles of the strains isolated in Yunnan in 2016 were the same as the strains that had previously been isolated in this Rattus flavipectus plague focus. The c3 spacer present in the previously isolated strains was absent in the spacer arrays of the Ypc CRISPR loci of the strains isolated in 2016. The MLVA analysis using MLVA (14+12) showed that the strains isolated from the human plague case and host animal plague infection in 2016 in Yunnan displayed different molecular patterns than the strains that had previously been isolated from Yunnan and adjacent provinces.

Techniques for extracting small, single channel ion currents from background noise are described and tested. It is assumed that single channel currents are generated by a first-order, finite-state, discrete-time, Markov process to which is added 'white' background noise from the recording apparatus (electrode, amplifiers, etc). Given the observations and the statistics of the background noise, the techniques described here yield a posteriori estimates of the most likely signal statistics, including the Markov model state transition probabilities, duration (open- and closed-time) probabilities, histograms, signal levels, and the most likely state sequence. Using variations of several algorithms previously developed for solving digital estimation problems, we have demonstrated that: (1) artificial, small, first-order, finite-state, Markov model signals embedded in simulated noise can be extracted with a high degree of accuracy, (2) processing can detect signals that do not conform to a first-order Markov model but the method is less accurate when the background noise is not white, and (3) the techniques can be used to extract from the baseline noise single channel currents in neuronal membranes. Some studies have been included to test the validity of assuming a first-order Markov model for biological signals. This method can be used to obtain directly from digitized data, channel characteristics such as amplitude distributions, transition matrices and open- and closed-time durations.

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We analyzed 10 isolates of Francisella tularensis subspecies holarctica from China and assigned them to known clades by using canonical single-nucleotide polymorphisms. We found 4 diverse subtypes, including 3 from the most basal lineage, biovar japonica. This result indicates unprecedented levels of diversity from a single region and suggests new models for emergence.