30 research outputs found

    Cloud-based Control of Thermal Based Manufacturing Processes

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    AbstractWith non-conventional manufacturing processes, being increasingly integrated into manufacturing process chains, controllers and control strategies, remote nowadays, have to take into account a plethora of phenomena and criteria. The current study addresses the challenges, associated with the framework of the thermal oriented processes, having holistic (digital) modelling as a main objective. Herein two different case studies are performed; numerical examples regarding big data impact on manufacturing and simulation-based paradigms of control design taking into account communications. Implementation of the aforementioned takes into account the controller's complexity

    Retinoic Acid-Dependent Signaling Pathways and Lineage Events in the Developing Mouse Spinal Cord

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    Studies in avian models have demonstrated an involvement of retinoid signaling in early neural tube patterning. The roles of this signaling pathway at later stages of spinal cord development are only partly characterized. Here we use Raldh2-null mouse mutants rescued from early embryonic lethality to study the consequences of lack of endogenous retinoic acid (RA) in the differentiating spinal cord. Mid-gestation RA deficiency produces prominent structural and molecular deficiencies in dorsal regions of the spinal cord. While targets of Wnt signaling in the dorsal neuronal lineage are unaltered, reductions in Fibroblast Growth Factor (FGF) and Notch signaling are clearly observed. We further provide evidence that endogenous RA is capable of driving stem cell differentiation. Raldh2 deficiency results in a decreased number of spinal cord derived neurospheres, which exhibit a reduced differentiation potential. Raldh2-null neurospheres have a decreased number of cells expressing the neuronal marker β-III-tubulin, while the nestin-positive cell population is increased. Hence, in vivo retinoid deficiency impaired neural stem cell growth. We propose that RA has separable functions in the developing spinal cord to (i) maintain high levels of FGF and Notch signaling and (ii) drive stem cell differentiation, thus restricting both the numbers and the pluripotent character of neural stem cells

    Effect of surgical experience and spine subspecialty on the reliability of the {AO} Spine Upper Cervical Injury Classification System

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    OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience (< 5 years, 5–10 years, 10–20 years, and > 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson’s chi-square or Fisher’s exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level (< 5 years: 0.74 vs 5–10 years: 0.69 vs 10–20 years: 0.69 vs > 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 (< 5 years: 0.67 vs 5–10 years: 0.62 vs 10–20 years: 0.61 vs > 20 years: 0.62), and only surgeons with > 20 years of experience did not have substantial reliability on assessment 2 (< 5 years: 0.62 vs 5–10 years: 0.61 vs 10–20 years: 0.61 vs > 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system

    Current perspectives of the signaling pathways directing neural crest induction

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    The neural crest is a migratory population of embryonic cells with a tremendous potential to differentiate and contribute to nearly every organ system in the adult body. Over the past two decades, an incredible amount of research has given us a reasonable understanding of how these cells are generated. Neural crest induction involves the combinatorial input of multiple signaling pathways and transcription factors, and is thought to occur in two phases from gastrulation to neurulation. In the first phase, FGF and Wnt signaling induce NC progenitors at the border of the neural plate, activating the expression of members of the Msx, Pax, and Zic families, among others. In the second phase, BMP, Wnt, and Notch signaling maintain these progenitors and bring about the expression of definitive NC markers including Snail2, FoxD3, and Sox9/10. In recent years, additional signaling molecules and modulators of these pathways have been uncovered, creating an increasingly complex regulatory network. In this work, we provide a comprehensive review of the major signaling pathways that participate in neural crest induction, with a focus on recent developments and current perspectives. We provide a simplified model of early neural crest development and stress similarities and differences between four major model organisms: Xenopus, chick, zebrafish, and mouse

    READ @your library John Arquilla and ADM James Stavridis (poster)

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    A project of the Dudley Knox Library at the Naval Postgraduate School

    READ @your library John Arquilla and ADM James Stavridis (bookmark)

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    A project of the Dudley Knox Library at the Naval Postgraduate School

    Increasing the industrial uptake of additive manufacturing processes: A training framework

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    Additive Manufacturing (AM) is one of the key technologies of Industry 4.0, offering unique advantages and capabilities. The interest in AM has been steadily increasing, leading to its rapid recent growth and improvement in all its aspects. However, its wider adoption is hindered by various barriers, the most important of which are the relatively high initial investment cost, part quality issues, limited material choices, and lack of expertise. The research community, AM machine developers, and larger enterprises are continuously contributing to the improvement of the first three factors. Nonetheless, the same cannot be stated for the barrier of limited expertise, leading the industrial sector to a perpetual lack of knowledge and, therefore, reluctance for a potential AM uptake. This study is addressing the need of the industrial sector for structured and organized expertise training for the fruitful exploitation of AM, paving the road for its wider application. The guidelines for an industrial-oriented AM training curriculum are set through the development of an AM training framework. The different AM thematic areas are classified into educational modules, which are separately analyzed, considering the participants’ active role and hands-on practice. The proposed step-by-step approach builds up from introductory to more advanced concepts, ensuring flexibility and simultaneously encompassing the needs of all industrial stakeholders (engineers, designers, managers, operators). Additionally, strategies corroborating the accessibility of the proposed framework are discussed, as well as dissemination policies and tools to facilitate its industrial endorsement
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