2,408 research outputs found

    Transferability of Deep Learning Algorithms for Malignancy Detection in Confocal Laser Endomicroscopy Images from Different Anatomical Locations of the Upper Gastrointestinal Tract

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    Squamous Cell Carcinoma (SCC) is the most common cancer type of the epithelium and is often detected at a late stage. Besides invasive diagnosis of SCC by means of biopsy and histo-pathologic assessment, Confocal Laser Endomicroscopy (CLE) has emerged as noninvasive method that was successfully used to diagnose SCC in vivo. For interpretation of CLE images, however, extensive training is required, which limits its applicability and use in clinical practice of the method. To aid diagnosis of SCC in a broader scope, automatic detection methods have been proposed. This work compares two methods with regard to their applicability in a transfer learning sense, i.e. training on one tissue type (from one clinical team) and applying the learnt classification system to another entity (different anatomy, different clinical team). Besides a previously proposed, patch-based method based on convolutional neural networks, a novel classification method on image level (based on a pre-trained Inception V.3 network with dedicated preprocessing and interpretation of class activation maps) is proposed and evaluated. The newly presented approach improves recognition performance, yielding accuracies of 91.63% on the first data set (oral cavity) and 92.63% on a joint data set. The generalization from oral cavity to the second data set (vocal folds) lead to similar area-under-the-ROC curve values than a direct training on the vocal folds data set, indicating good generalization.Comment: Erratum for version 1, correcting the number of CLE image sequences used in one data se

    Femtosecond nonlinear ultrasonics in gold probed with ultrashort surface plasmons

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    Fundamental interactions induced by lattice vibrations on ultrafast time scales become increasingly important for modern nanoscience and technology. Experimental access to the physical properties of acoustic phonons in the THz frequency range and over the entire Brillouin zone is crucial for understanding electric and thermal transport in solids and their compounds. Here, we report on the generation and nonlinear propagation of giant (1 percent) acoustic strain pulses in hybrid gold/cobalt bilayer structures probed with ultrafast surface plasmon interferometry. This new technique allows for unambiguous characterization of arbitrary ultrafast acoustic transients. The giant acoustic pulses experience substantial nonlinear reshaping already after a propagation distance of 100 nm in a crystalline gold layer. Excellent agreement with the Korteveg-de Vries model points to future quantitative nonlinear femtosecond THz-ultrasonics at the nano-scale in metals at room temperature

    Occupation time of exclusion processes with conductances

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    Em publicação em "Journal of statistical physics". ISSN 0022-4715.We obtain the fluctuations for the occupation time of one-dimensional symmetric exclusion processes with speed change, where the transition rates ({\em conductances}) are driven by a general function WW. The approach does not require sharp bounds on the spectral gap of the system nor the jump rates to be bounded from above or below. We present some examples and for one of them, we observe that the fluctuations of the current are trivial, but the fluctuations of the occupation time are given by a fractional Brownian Motion. This shows that, in general, the fluctuations of the current and of the occupation time are not of same order.CAPESFundação para a Ciência e a Tecnologia (FCT)CNP

    Interdependence, interaction, and relationships

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    Interdependence theory presents a logical analysis of the structure of interpersonal situations, offering a conceptual framework in which interdependence situations can be analyzed in terms of six dimensions. Specific situations present specific problems and opportunities, logically implying the relevance of specific motives and permitting their expression. Via the concept of transformation, the theory explains how interaction is shaped by broader considerations such as long-term goals and concern for a partner's welfare. The theory illuminates our understanding of social-cognitive processes that are of longstanding interest to psychologists such as cognition and affect, attribution, and self-presentation. The theory also explains adaptation to repeatedly encountered interdependence patterns, as well as the embodiment of such adaptations in interpersonal dispositions, relationship-specific motives, and social norms

    Should Research Ethics Encourage the Production of Cost-Effective Interventions?

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    This project considers whether and how research ethics can contribute to the provision of cost-effective medical interventions. Clinical research ethics represents an underexplored context for the promotion of cost-effectiveness. In particular, although scholars have recently argued that research on less-expensive, less-effective interventions can be ethical, there has been little or no discussion of whether ethical considerations justify curtailing research on more expensive, more effective interventions. Yet considering cost-effectiveness at the research stage can help ensure that scarce resources such as tissue samples or limited subject popula- tions are employed where they do the most good; can support parallel efforts by providers and insurers to promote cost-effectiveness; and can ensure that research has social value and benefits subjects. I discuss and rebut potential objections to the consideration of cost-effectiveness in research, including the difficulty of predicting effectiveness and cost at the research stage, concerns about limitations in cost-effectiveness analysis, and worries about overly limiting researchers’ freedom. I then consider the advantages and disadvantages of having certain participants in the research enterprise, including IRBs, advisory committees, sponsors, investigators, and subjects, consider cost-effectiveness. The project concludes by qualifiedly endorsing the consideration of cost-effectiveness at the research stage. While incorporating cost-effectiveness considerations into the ethical evaluation of human subjects research will not on its own ensure that the health care system realizes cost-effectiveness goals, doing so nonetheless represents an important part of a broader effort to control rising medical costs

    Improvements in survival of the uncemented Nottingham Total Shoulder prosthesis: a prospective comparative study

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    <p>Abstract</p> <p>Background</p> <p>The uncemented Nottingham Total Shoulder Replacement prosthesis system (Nottingham TSR) was developed from the previous BioModular<sup>® </sup>shoulder prosthesis taking into consideration the causes of the initial implant's failure.</p> <p>We investigated the impact of changes in the design of Nottingham TSR prosthesis on its survivorship rate.</p> <p>Methods</p> <p>Survivorship analyses of three types of uncemented total shoulder arthroplasty prostheses (BioModular<sup>®</sup>, initial Nottingham TSR and current Nottingham TSR systems with 11, 8 and 4 year survivorship data respectively) were compared. All these prostheses were implanted for the treatment of disabling pain in the shoulder due to primary and secondary osteoarthritis or rheumatoid arthritis. Each type of the prosthesis studied was implanted in consecutive group of patients – 90 patients with BioModular<sup>® </sup>system, 103 with the initial Nottingham TSR and 34 patients with the current Nottingham TSR system.</p> <p>The comparison of the annual cumulative survivorship values in the compatible time range between the three groups was done according to the paired <it>t </it>test.</p> <p>Results</p> <p>The 8-year and 11-year survivorship rates for the initially used modified BioModular<sup>® </sup>uncemented prosthesis were relatively low (75.6% and 71.7% respectively) comparing to the reported survivorship of the conventional cemented implants. The 8-year survivorship for the uncemented Nottingham TSR prosthesis was significantly higher (81.8%), but still not in the desired range of above 90%, that is found in other cemented designs. Glenoid component loosening was the main factor of prosthesis failure in both prostheses and mainly occurred in the first 4 postoperative years. The 4-year survivorship of the currently re-designed Nottingham TSR prosthesis, with hydroxylapatite coating of the glenoid baseplate, was significantly higher, 93.1% as compared to 85.1% of the previous Nottingham TSR.</p> <p>Conclusion</p> <p>The initial Nottingham shoulder prosthesis showed significantly higher survivorship than the BioModular<sup>® </sup>uncemented prosthesis, but lower than expected. Subsequently re-designed Nottingham TSR system presented a high short term survivorship rate that encourages its ongoing use</p

    Paleophysical Oceanography with an Emphasis on Transport Rates

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    Paleophysical oceanography is the study of the behavior of the fluid ocean of the past, with a specific emphasis on its climate implications, leading to a focus on the general circulation. Even if the circulation is not of primary concern, heavy reliance on deep-sea cores for past climate information means that knowledge of the oceanic state when the sediments were laid down is a necessity. Like the modern problem, paleoceanography depends heavily on observations, and central difficulties lie with the very limited data types and coverage that are, and perhaps ever will be, available. An approximate separation can be made into static descriptors of the circulation (e.g., its water-mass properties and volumes) and the more difficult problem of determining transport rates of mass and other properties. Determination of the circulation of the Last Glacial Maximum is used to outline some of the main challenges to progress. Apart from sampling issues, major difficulties lie with physical interpretation of the proxies, transferring core depths to an accurate timescale (the “age-model problem”), and understanding the accuracy of time-stepping oceanic or coupled-climate models when run unconstrained by observations. Despite the existence of many plausible explanatory scenarios, few features of the paleocirculation in any period are yet known with certainty.National Science Foundation (U.S.) (grant OCE-0645936

    Tolerance to the Neuron-Specific Paraneoplastic HuD Antigen

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    Experiments dating back to the 1940's have led to the hypothesis that the brain is an immunologically privileged site, shielding its antigens from immune recognition. The paraneoplastic Hu syndrome provides a powerful paradigm for addressing this hypothesis; it is believed to develop because small cell lung cancers (SCLC) express the neuron-specific Hu protein. This leads to an Hu-specific tumor immune response that can develop into an autoimmune attack against neurons, presumably when immune privilege in the brain is breached. Interestingly, all SCLC express the onconeural HuD antigen, and clinically useful tumor immune responses can be detected in up to 20% of patients, yet the paraneoplastic neurologic syndrome is extremely rare. We found that HuD-specific CD8+ T cells are normally present in the mouse T cell repertoire, but are not expanded upon immunization, although they can be detected after in vitro expansion. In contrast, HuD-specific T cells could be directly activated in HuD null mice, without the need for in vitro expansion. Taken together, these results demonstrate robust tolerance to the neuronal HuD antigen in vivo, and suggest a re-evaluation of the current concept of immune privilege in the brain
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