Search

Case-control studies have shown that patients with Crohn's disease (CD) have a microbial composition different from healthy individuals. Although the causes of CD are unknown, epidemiologic studies suggest that diet is an important contributor to CD risk, potentially via modulation of bacterial composition and gut inflammation. We hypothesized that long-term dietary clusters (DCs) are associated with gut microbiome compositions and gut inflammation. Our objectives were to identify dietary patterns and assess whether they are associated with alterations in specific gut microbial compositions and subclinical levels of gut inflammation in a cohort of healthy first-degree relatives (FDRs) of patients with CD.As part of the Genetic, Environmental, Microbial (GEM) Project, we recruited a cohort of 2289 healthy FDRs of patients with CD. Individuals provided stool samples and answered a validated food frequency questionnaire reflecting their habitual diet during the year before sample collection. Unsupervised analysis identified 3 dietary and 3 microbial composition clusters.DC3, resembling the Mediterranean diet, was strongly associated with a defined microbial composition, with an increased abundance of fiber-degrading bacteria, such as Ruminococcus, as well as taxa such as Faecalibacterium. The DC3 diet was also significantly associated with lower levels of subclinical gut inflammation, defined by fecal calprotectin, compared with other dietary patterns. No significant associations were found between individual food items and fecal calprotectin, suggesting that long-term dietary patterns rather than individual food items contribute to subclinical gut inflammation. Additionally, mediation analysis demonstrated that DC3 had a direct effect on subclinical inflammation that was partially mediated by the microbiota.Overall, these results indicated that Mediterranean-like dietary patterns are associated with microbiome and lower intestinal inflammation. This study will help guide future dietary strategies that affect microbial composition and host gut inflammation to prevent diseases.

Background & Aims Altered gut microbiota composition and function have been associated with inflammatory bowel diseases, including ulcerative colitis (UC), but the causality and mechanisms remain unknown. Methods We applied 16S ribosomal RNA gene sequencing, shotgun metagenomic sequencing, in vitro functional assays, and gnotobiotic colonizations to define the microbial composition and function in fecal samples obtained from a cohort of healthy individuals at risk for inflammatory bowel diseases (pre-UC) who later developed UC (post-UC) and matched healthy control individuals (HCs). Results Microbiota composition of post-UC samples was different from HC and pre-UC samples; however, functional analysis showed increased fecal proteolytic and elastase activity before UC onset. Metagenomics identified more than 22,000 gene families that were significantly different between HC, pre-UC, and post-UC samples. Of these, 237 related to proteases and peptidases, suggesting a bacterial component to the pre-UC proteolytic signature. Elastase activity inversely correlated with the relative abundance of Adlercreutzia and other potentially beneficial taxa and directly correlated with known proteolytic taxa, such as Bacteroides vulgatus. High elastase activity was confirmed in Bacteroides isolates from fecal samples. The bacterial contribution and functional significance of the proteolytic signature were investigated in germ-free adult mice and in dams colonized with HC, pre-UC, or post-UC microbiota. Mice colonized with or born from pre-UC–colonized dams developed higher fecal proteolytic activity and an inflammatory immune tone compared with HC-colonized mice. Conclusions We have identified increased fecal proteolytic activity that precedes the clinical diagnosis of UC and associates with gut microbiota changes. This proteolytic signature may constitute a noninvasive biomarker of inflammation to monitor at-risk populations that can be targeted therapeutically with antiproteases.

Background & Aims Increased intestinal permeability has been associated with Crohn’s disease (CD), but it is not clear whether it is a cause or result of the disease. We performed a prospective study to determine whether increased intestinal permeability is associated with future development of CD. Methods We assessed the intestinal permeability, measured by the urinary fractional excretion of lactulose-to-mannitol ratio (LMR) at recruitment in 1420 asymptomatic first-degree relatives (6–35 years old) of patients with CD (collected from 2008 through 2015). Participants were then followed up for a diagnosis of CD from 2008 to 2017, with a median follow-up time of 7.8 years. We analyzed data from 50 participants who developed CD after a median of 2.7 years during the study period, along with 1370 individuals who remained asymptomatic until October 2017. We used the Cox proportional hazards model to evaluate time-related risk of CD based on the baseline LMR. Results An abnormal LMR (>0.03) was associated with a diagnosis of CD during the follow-up period (hazard ratio, 3.03; 95% CI, 1.64–5.63; P = 3.97 × 10–4). This association remained significant even when the test was performed more than 3 years before the diagnosis of CD (hazard ratio, 1.62; 95% CI, 1.051–2.50; P = .029). Conclusions Increased intestinal permeability is associated with later development of CD; these findings support a model in which altered intestinal barrier function contributes to pathogenesis. Abnormal gut barrier function might serve as a biomarker for risk of CD onset.

This paper reports on a reactive docking behavior which uses a vision algorithm that grows linearly with the number of image pixels. The docking robot imprints (initializes) on a two-colored docking fiducial upon departing from the dock, then uses region statistics to adapt the color segmentation in changing lighting conditions. The docking behavior was implemented on a marsupial team of robots, where a daughter micro-rover had to reenter the mother robot from an approach zone with a 2 m radius and 140/spl deg/ angular width with a tolerance of /spl plusmn/5 and /spl plusmn/2 cm. Testing during outdoor conditions (noon, dusk) and challenging indoor scenarios (flashing lights) showed that using adaptation and imprinting was more robust than using imprinting atone.

This paper addresses position estimation of a micro-rover mobile robot (called the “daughter”) as a larger robot (the “mother”) tracks it through large spaces with unstructured lighting. Position estimation is necessary for localization, where the mother extracts the relative position of the daughter for mapping purposes, and for cooperative navigation, where the mother controls the daughter in real-time. The approach taken is to employ the Spherical Coordinate Transform color segmenter developed for medical applications as a low computational and hardware cost solution. Data was collected from 50 images taken in five types of lighting: fluorescent, tungsten, daylight lamp, natural daylight indoors and outdoors. The results show that average pixel error was 1.5, with an average error in distance estimation of 6.3 cm. The size of the error did not vary greatly with the type of lighting. The segmentation and distance tracking have also been implemented as a real-time tracking system. Using this system, the mother robot is able to autonomously control the micro-rover and display a map of the daughter's path in real-time using only a Pentium class processor and no specialized hardware.

This paper addresses position estimation of a micro-rover mobile robot (called the "daughter") as a larger robot (the "mother") tracks it through large spaces with unstructured lighting. Position estimation is necessary for localization, where the mother extracts the relative position of the daughter for mapping purposes, and for cooperative navigation, where the mother controls the daughter in real-time. The approach taken is to employ the spherical coordinate transform color segmenter developed for medical applications as a low computational and hardware cost solution. Data was collected from 50 images taken in five types of lighting: fluorescent, tungsten, daylight lamp, natural daylight indoors and outdoors. The results show that average pixel error was 1.5, with an average error in distance estimation of 6.3 cm. The size of the error did not vary greatly with the type of lighting. The segmentation and distance tracking have also been implemented as a real-time tracking system. Using this system, the mother robot is able to autonomously control the micro-rover and display a map of the daughter's path.

Since 1999, the members of the Perceptual Robotics Laboratory at the University of South Florida have worked with the Hillsborough County Fire Department on identifying opportunities for robotics in urban search and rescue. This paper provides an introduction to the USAR environment and the impact on sensors and platforms. It discusses the possible roles of mobile robots, and the need for adjustable autonomy.

The purpose of mobile robot competitions is to push the field of research and inspire future work. Our involvement in the Urban Search and Rescue event of the 2000 AAAI Mobile Robot Competition allowed us the opportunity to test our Urban Search and Rescue robot team in a standardized testbed. The result was ideas for future enhancements and research work. This article presents our experience as a case study on how mobile robot competitions promote research.

Physical cooperation between robotic agents frequently requires the ability to dock. This paper reports on a reactive docking behavior which uses a vision algorithm that grows linearly with image pixels. The docking behavior was implemented on a marsupial team of robots, where a daughter micro-rover had to re-enter the mother robot from an approach zone with a 2 meter radius and 140° angular width. Experiments showed that the docking behavior had a similar success rate and was faster than 22 teleoperators.