522 research outputs found

    Choledochoduodenal fistula presenting with pneumobilia in a patient with gallbladder cancer: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Spontaneous biliary tract fistulas are rare entities. Most of them are associated with long-standing gallstones (especially common bile duct stones, or recurrent biliary tract infections), some with more uncommon diseases such as gallbladder cancer. Some authors believe that back flow from fistulas predisposes patients to gallbladder cancer and some believe that cancer causes necrosis and fistula formation. Gallbladder cancer has a dismal prognosis and 85% of patients are dead within a year of diagnosis. A common complication of gallbladder cancer is obstruction of the common bile duct, which may produce multiple intra-hepatic abscesses in or near the tumor-laden gallbladder. Fistula formation may further complicate the clinical picture.</p> <p>Case presentation</p> <p>We present a case of choledochoduodenal fistula in a 60-year-old diabetic African-American woman with gallbladder cancer. The initial clinical presentation was confusing and complex. Our patient was also found to have a gallbladder fossa abscess that was drained percutaneously as another complicating factor relating to her cancer. She developed myocardial infarction, massive upper gastrointestinal bleeding and respiratory arrest during her stay in hospital. Computed tomography was very helpful in assessing our patient and we discuss how, in a patient with pneumobilia, it can be helpful for detecting fistula, air in bile ducts or to show contractions of the gallbladder.</p> <p>Conclusions</p> <p>We believe this case merits reporting as it shows an entity that is not frequently thought of, is hard to diagnose and can be fatal, as in our patient. Careful evaluation, and computed tomography studies and endoscopic retrograde cholangio-pancreatography are helpful in early diagnosis and finding better management options for these patients.</p

    Achieving Practical and Accurate Indoor Navigation for People with Visual Impairments

    Get PDF
    Methods that provide accurate navigation assistance to people with visual impairments often rely on instrumenting the environment with specialized hardware infrastructure. In particular, approaches that use sensor networks of Bluetooth Low Energy (BLE) beacons have been shown to achieve precise localization and accurate guidance while the structural modifications to the environment are kept at minimum. To install navigation infrastructure, however, a number of complex and time-critical activities must be performed. The BLE beacons need to be positioned correctly and samples of Bluetooth signal need to be collected across the whole environment. These tasks are performed by trained personnel and entail costs proportional to the size of the environment that needs to be instrumented. To reduce the instrumentation costs while maintaining a high accuracy, we improve over a traditional regression-based localization approach by introducing a novel, graph-based localization method using Pedestrian Dead Reckoning (PDR) and particle filter. We then study how the number and density of beacons and Bluetooth samples impact the balance between localization accuracy and set-up cost of the navigation environment. Studies with users show the impact that the increased accuracy has on the usability of our navigation application for the visually impaired

    Reduction of data size for transmission in localization of mobile robots

    Get PDF
    In the SLAM (Simultaneous Localization and Mapping) technology, an environmental map is generated by a mobile robot. When it results in failure, it is necessary to inspect the scene. This localization and browsing require transmission of video signal to a remote place. In the system in this paper, an indoor mobile robot has two cameras. One is the &quot;upward&quot; which captures scenery of ceiling. The other is &quot;forward&quot; for scenery in front of the robot. Video signals from the cameras are encoded and transmitted from the robot to a remote server. It causes a problem that data size is too huge to be transmitted. To cope with this problem, the Functionally Layered Coding (FLC) was reported. In the existing FLC, visual motions are estimated by using the rotation invariant phase only correlation (RI-POC) technique. It can estimate two kinds of motions -translation and rotation. However, it requires doubled computational complexity and many components to be transmitted. In this paper, we analyze relation between kinetic movements of a robot and visual motions observed in videos, and propose to replace RI-POC by a simple POC. It was confirmed that the proposed method reduced data size for transmission to 61.6%

    First GIS analysis of modern stone tools used by wild chimpanzees (Pan troglodytes verus) in Bossou, Guinea, West Africa

    Get PDF
    Stone tool use by wild chimpanzees of West Africa offers a unique opportunity to explore the evolutionary roots of technology during human evolution. However, detailed analyses of chimpanzee stone artifacts are still lacking, thus precluding a comparison with the earliest archaeological record. This paper presents the first systematic study of stone tools used by wild chimpanzees to crack open nuts in Bossou (Guinea-Conakry), and applies pioneering analytical techniques to such artifacts. Automatic morphometric GIS classification enabled to create maps of use wear over the stone tools (anvils, hammers, and hammers/anvils), which were blind tested with GIS spatial analysis of damage patterns identified visually. Our analysis shows that chimpanzee stone tool use wear can be systematized and specific damage patterns discerned, allowing to discriminate between active and passive pounders in lithic assemblages. In summary, our results demonstrate the heuristic potential of combined suites of GIS techniques for the analysis of battered artifacts, and have enabled creating a referential framework of analysis in which wild chimpanzee battered tools can for the first time be directly compared to the early archaeological record.Leverhulme Trust [IN-052]; MEXT [20002001, 24000001]; JSPS-U04-PWS; FCT-Portugal [SFRH/BD/36169/2007]; Wenner-Gren Foundation for Anthropological Researc

    Symbol Emergence in Cognitive Developmental Systems: a Survey

    Get PDF
    OAPA Humans use signs, e.g., sentences in a spoken language, for communication and thought. Hence, symbol systems like language are crucial for our communication with other agents and adaptation to our real-world environment. The symbol systems we use in our human society adaptively and dynamically change over time. In the context of artificial intelligence (AI) and cognitive systems, the symbol grounding problem has been regarded as one of the central problems related to symbols. However, the symbol grounding problem was originally posed to connect symbolic AI and sensorimotor information and did not consider many interdisciplinary phenomena in human communication and dynamic symbol systems in our society, which semiotics considered. In this paper, we focus on the symbol emergence problem, addressing not only cognitive dynamics but also the dynamics of symbol systems in society, rather than the symbol grounding problem. We first introduce the notion of a symbol in semiotics from the humanities, to leave the very narrow idea of symbols in symbolic AI. Furthermore, over the years, it became more and more clear that symbol emergence has to be regarded as a multifaceted problem. Therefore, secondly, we review the history of the symbol emergence problem in different fields, including both biological and artificial systems, showing their mutual relations. We summarize the discussion and provide an integrative viewpoint and comprehensive overview of symbol emergence in cognitive systems. Additionally, we describe the challenges facing the creation of cognitive systems that can be part of symbol emergence systems

    Solitary neurofibroma of the gingiva with prominent differentiation of Meissner bodies : a case report

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Oral neurofibromas are peripheral nerve sheath tumors, similar to schwannomas. Histological variations in oral neurofibromas are relatively uncommon.</p> <p>Case presentation</p> <p>Here, we present a case of unique variation in the observed characteristics of a neurofibroma, with no relation to neurofibromatosis type-1 or von Recklinghausen disease of the skin. The neurofibroma was observed in the right mandibular gingiva of a 32-year-old Japanese woman. Histologically, it differed from conventional neurofibromas in that the tumor was composed of a mixture of fine fibrillary collagen in sheets and/or cords of neoplastic Schwann cells containing numerous clusters of Meissner bodies. Histologically, these bodies were in contact with neoplastic Schwann cells. The Meissner bodies were immunopositive for S-100 protein, neuron-specific enolase, and vimentin, but were negative for calretinin. CD34-positive spindle cells were observed around the Meissner bodies. No recurrence or signs of other tumors have been observed in the patient for 5 years after tumor resection.</p> <p>Conclusion</p> <p>To the best of our knowledge, no formal descriptions of sporadic, solitary neurofibromas containing numerous Meissner bodies occurring in the oral cavity are available in literature. We believe that an uncommon proliferation of Meissner bodies, as seen in the present case, may result from aberrant differentiation of neoplastic Schwann cells.</p

    The Anti-Tumor Effect of HDAC Inhibition in a Human Pancreas Cancer Model Is Significantly Improved by the Simultaneous Inhibition of Cyclooxygenase 2

    Get PDF
    Pancreatic ductal adenocarcinoma is the fourth leading cause of cancer death worldwide, with no satisfactory treatment to date. In this study, we tested whether the combined inhibition of cyclooxygenase-2 (COX-2) and class I histone deacetylase (HDAC) may results in a better control of pancreatic ductal adenocarcinoma. The impact of the concomitant HDAC and COX-2 inhibition on cell growth, apoptosis and cell cycle was assessed first in vitro on human pancreas BxPC-3, PANC-1 or CFPAC-1 cells treated with chemical inhibitors (SAHA, MS-275 and celecoxib) or HDAC1/2/3/7 siRNA. To test the potential antitumoral activity of this combination in vivo, we have developed and characterized, a refined chick chorioallantoic membrane tumor model that histologically and proteomically mimics human pancreatic ductal adenocarcinoma. The combination of HDAC1/3 and COX-2 inhibition significantly impaired proliferation of BxPC-3 cells in vitro and stalled entirely the BxPC-3 cells tumor growth onto the chorioallantoic membrane in vivo. The combination was more effective than either drug used alone. Consistently, we showed that both HDAC1 and HDAC3 inhibition induced the expression of COX-2 via the NF-kB pathway. Our data demonstrate, for the first time in a Pancreatic Ductal Adenocarcinoma (PDAC) model, a significant action of HDAC and COX-2 inhibitors on cancer cell growth, which sets the basis for the development of potentially effective new combinatory therapies for pancreatic ductal adenocarcinoma patients.Peer reviewe
    corecore