4,476 research outputs found

    Vision-based toddler tracking at home

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    This paper presents a vision-based toddler tracking system for detecting risk factors of a toddler's fall within the home environment. The risk factors have environmental and behavioral aspects and the research in this paper focuses on the behavioral aspects. Apart from common image processing tasks such as background subtraction, the vision-based toddler tracking involves human classification, acquisition of motion and position information, and handling of regional merges and splits. The human classification is based on dynamic motion vectors of the human body. The center of mass of each contour is detected and connected with the closest center of mass in the next frame to obtain position, speed, and directional information. This tracking system is further enhanced by dealing with regional merges and splits due to multiple object occlusions. In order to identify the merges and splits, two directional detections of closest region centers are conducted between every two successive frames. Merges and splits of a single object due to errors in the background subtraction are also handled. The tracking algorithms have been developed, implemented and tested

    A smart vision sensor for detecting risk factors of a toddler's fall in a home environment

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    This paper presents a smart vision sensor for detecting risk factors of a toddler's fall in an indoor home environment assisting parents' supervision to prevent fall injuries. We identified the risk factors by analyzing real fall injury stories and referring to a related organization's suggestions to prevent falls. In order to detect the risk factors using computer vision, two major image processing methods, clutter detection and toddler tracking, were studied with using only one commercial web-camera. For practical purposes, there is no need for a toddler to wear any sensors or markers. The algorithms for detection have been developed, implemented and tested

    Quantum Control of Interacting Bosons in Periodic Optical Lattice

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    We study the avoided crossings in the dynamics of quantum controlled excitations for an interacting two-boson system in an optical lattice. Specifically, we perform numerical simulations of quantum control in this system where driving pulses connect the undriven stationary states in a manner characteristic of Stimulated Raman Adiabatic Passage (STIRAP). We demonstrate that the dynamics of such a transition is affected by chaos induced avoided crossings, resulting in a loss in coherence of the final outcome in the adiabatic limit.Comment: Accepted for publication in Physica E. Typo corrections to final versio

    An Ensemble-Based Protocol for the Computational Prediction of Helix-Helix Interactions in G Protein-Coupled Receptors using Coarse-Grained Molecular Dynamics

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    The accurate identification of the specific points of interaction between G protein-coupled receptor (GPCR) oligomers is essential for the design of receptor ligands targeting oligomeric receptor targets. A coarse-grained molecular dynamics computer simulation approach would provide a compelling means of identifying these specific protein–protein interactions and could be applied both for known oligomers of interest and as a high-throughput screen to identify novel oligomeric targets. However, to be effective, this in silico modeling must provide accurate, precise, and reproducible information. This has been achieved recently in numerous biological systems using an ensemble-based all-atom molecular dynamics approach. In this study, we describe an equivalent methodology for ensemble-based coarse-grained simulations. We report the performance of this method when applied to four different GPCRs known to oligomerize using error analysis to determine the ensemble size and individual replica simulation time required. Our measurements of distance between residues shown to be involved in oligomerization of the fifth transmembrane domain from the adenosine A2A receptor are in very good agreement with the existing biophysical data and provide information about the nature of the contact interface that cannot be determined experimentally. Calculations of distance between rhodopsin, CXCR4, and β1AR transmembrane domains reported to form contact points in homodimers correlate well with the corresponding measurements obtained from experimental structural data, providing an ability to predict contact interfaces computationally. Interestingly, error analysis enables identification of noninteracting regions. Our results confirm that GPCR interactions can be reliably predicted using this novel methodology

    dalmatian: A Package for Fitting Double Hierarchical Linear Models in R via JAGS and nimble

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    Traditional regression models, including generalized linear mixed models, focus on understanding the deterministic factors that affect the mean of a response variable. Many biological studies seek to understand non-deterministic patterns in the variance or dispersion of a phenotypic or ecological response variable. We describe a new R package, dalmatian, that provides methods for fitting double hierarchical generalized linear models incorporating fixed and random predictors of both the mean and variance. Models are fit via Markov chain Monte Carlo sampling implemented in either JAGS or nimble and the package provides simple functions for monitoring the sampler and summarizing the results. We illustrate these functions through an application to data on food delivery by breeding pied flycatchers (Ficedula hypoleuca). Our intent is that this package makes it easier for practitioners to implement these models without having to learn the intricacies of Markov chain Monte Carlo methods

    A study on detection of risk factors of a toddler's fall injuries using visual dynamic motion cues

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    The research in this thesis is intended to aid caregivers’ supervision of toddlers to prevent accidental injuries, especially injuries due to falls in the home environment. There have been very few attempts to develop an automatic system to tackle young children’s accidents despite the fact that they are particularly vulnerable to home accidents and a caregiver cannot give continuous supervision. Vision-based analysis methods have been developed to recognise toddlers’ fall risk factors related to changes in their behaviour or environment. First of all, suggestions to prevent fall events of young children at home were collected from well-known organisations for child safety. A large number of fall records of toddlers who had sought treatment at a hospital were analysed to identify a toddler’s fall risk factors. The factors include clutter being a tripping or slipping hazard on the floor and a toddler moving around or climbing furniture or room structures. The major technical problem in detecting the risk factors is to classify foreground objects into human and non-human, and novel approaches have been proposed for the classification. Unlike most existing studies, which focus on human appearance such as skin colour for human detection, the approaches addressed in this thesis use cues related to dynamic motions. The first cue is based on the fact that there is relative motion between human body parts while typical indoor clutter does not have such parts with diverse motions. In addition, other motion cues are employed to differentiate a human from a pet since a pet also moves its parts diversely. They are angle changes of ellipse fitted to each object and history of its actual heights to capture the various posture changes and different body size of pets. The methods work well as long as foreground regions are correctly segmented.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Associations of social and economic and pregnancy exposures with blood pressure in UK White British and Pakistani children age 4/5.

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    South Asians have higher rates of coronary heart disease (CHD) than White European individuals. Blood pressure (BP) is one of the most important risk factors for CHD and ethnic differences in BP have been identified in childhood. Early life exposures could explain some of these differences. We examined associations of family social and economic and maternal pregnancy exposures and BP at age 4/5 in 1644 White British and 1824 Pakistani mother-offspring pairs from the Born in Bradford study. We found that systolic BP was similar but diastolic BP was higher, in Pakistani compared to White British children (adjusted mean differences were -0.170 mmHg 95% CI -0.884, 0.543 for systolic BP; 1.328 mmHg 95% CI 0.592, 2.064 for diastolic BP). Social and economic exposures were not associated with BP in either ethnic group. Maternal BMI was positively associated with BP in both groups but this association was mediated by child BMI. Only gestational hypertension was associated with child systolic and diastolic BP and this was only identified in Pakistani mother-offspring pairs. These findings suggest that Pakistani populations may have a different BP trajectory compared to White British groups and that this is already evident at age 4/5 years

    Histological 3D reconstruction and in vivo lineage tracing of the human endometrium

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    Regular menstrual shedding and repair of the endometrial functionalis is unique to humans and higher‐order primates. The current consensus postulates endometrial glands to have a single‐tubular architecture, where multi‐potential stem cells reside in the blind‐ending glandular‐bases. Utilising fixed samples from patients, we have studied the three‐dimensional (3D) micro‐architecture of the human endometrium. We demonstrate that some non‐branching, single, vertical functionalis glands originate from a complex horizontally interconnecting network of basalis glands. The existence of a multipotent endometrial epithelial stem cell capable of regenerating the entire complement of glandular lineages was demonstrated by in vivo lineage tracing, using naturally occurring somatic mitochondrial DNA mutations as clonal markers. Vertical tracking of mutated clones showed that at least one stem‐cell population resides in the basalis glands. These novel findings provide insight into the efficient and scar‐less regenerative potential of the human endometrium

    Does human endometrial LGR5 gene expression suggest the existence of another hormonally regulated epithelial stem cell niche?

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    STUDY QUESTION Is human endometrial leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) gene expression limited to the postulated epithelial stem cell niche, stratum basalis glands, and is it hormonally regulated? SUMMARY ANSWER LGR5 expressing cells are not limited to the postulated stem cell niche but LGR5 expression is hormonally regulated. WHAT IS KNOWN ALREADY The human endometrium is a highly regenerative tissue; however, endometrial epithelial stem cell markers are yet to be confirmed. LGR5 is a marker of stem cells in various epithelia. STUDY DESIGN, SIZE, DURATION The study was conducted at a University Research Institute. Endometrial samples from 50 healthy women undergoing benign gynaecological surgery with no endometrial pathology at the Liverpool Women’s hospital were included and analysed in the following six sub-categories; proliferative, secretory phases of menstrual cycle, postmenopausal, those using oral and local progestagens and samples for in vitro explant culture. PARTICIPANTS/MATERIALS, SETTING, METHODS In this study, we used the gold standard method, in situ hybridisation (ISH) along with qPCR and a systems biology approach to study the location of LGR5 gene expression in full thickness human endometrium and Fallopian tubes. The progesterone regulation of endometrial LGR5 was examined in vivo and in short-term cultured endometrial tissue explants in vitro. LGR5 expression was correlated with epithelial proliferation (Ki67), and expression of previously reported epithelia progenitor markers (SOX9 and SSEA-1) immunohistochemistry (IHC). MAIN RESULTS AND THE ROLE OF CHANCE LGR5 gene expression was significantly higher in the endometrial luminal epithelium than in all other epithelial compartments in the healthy human endometrium, including the endometrial stratum basalis (P < 0.05). The strongest SSEA-1 and SOX9 staining was observed in the stratum basalis glands, but the general trend of SOX9 and SSEA-1 expression followed the same cyclical pattern of expression as LGR5. Stratum functionalis epithelial Ki67-LI and LGR5 expression levels correlated significantly (r = 0.74, P = 0.01), however, they did not correlate in luminal and stratum basalis epithelium (r = 0.5 and 0.13, respectively). Endometrial LGR5 demonstrates a dynamic spatiotemporal expression pattern, suggesting hormonal regulation. Oral and local progestogens significantly reduced endometrial LGR5 mRNA levels compared with women not on hormonal treatment (P < 0.01). Our data were in agreement with in silico analysis of published endometrial microarrays. LARGE SCALE DATA We did not generate our own large scale data but interrogated publically available large scale data sets. LIMITATIONS, REASONS FOR CAUTION In the absence of reliable antibodies for human LGR5 protein and validated lineage markers for the various epithelial populations that potentially exist within the endometrium, our study does not formally characterise or examine the functional ability of the resident LGR5+ cells as multipotent. WIDER IMPLICATIONS OF THE FINDINGS These data will facilitate future lineage tracing studies in the human endometrial epithelium; to identify the location of stem cells and further complement the in vitro functional studies, to confirm if the LGR5 expressing epithelial cells indeed represent the epithelial stem cell population. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by funding from the Wellbeing of Women project grant (RTF510) and Cancer Research UK (A14895). None of the authors have any conflicts of interest to disclose

    Antralization at the edge of proximal gastric ulcers: Does Helicobacter pylori infection play a role?

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    Aim: To determine the prevalence of antralization at the edge of proximal gastric ulcers, and the effect of H. pylori eradication on the mucosal appearances. Methods: Biopsies were taken from the antrum, body and the ulcer edge of patients with benign proximal gastric ulcers before and one year after treatment. Gastric mucosa was classified as antral, transitional or body type. H. pylori positive patients received either triple therapy, or omeprazole. Results: Patients with index ulcers in the incisura, body or fundus (n=116) were analyzed. Antral-type mucosa was more prevalent at the ulcer edge in H. pylori-positive patients than H. pylori-negative patients (93 % vs 60 %, OR=8.95, 95 %CI: 2.47-32.4, P=0.001). At one year, there was a significant reduction in the prevalence of antralization (from 93 % to 61 %, P=0.004) at the ulcer edge in patients with H. pylori being eradicated. However, there was no difference in the prevalence of antralization at the ulcer edge in those with persistent infection. Conclusion: H. pylori infection is associated with antralization at the edge of proximal gastric ulcers, which may be reversible in some patients after eradication of the infection.published_or_final_versio
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