307 research outputs found

    Lhx6 regulates the migration of cortical interneurons from the ventral telencephalon but does not specify their GABA phenotype

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    The LIM homeodomain family of transcription factors is involved in many processes in the developing CNS, ranging from cell fate specification to connectivity. A member of this family of transcription factors, lhx6, is expressed in the medial ganglionic eminence(MGE) of the ventral telencephalon, where the vast majority of cortical interneurons are generated. Its expression in the GABA-containing MGE cells that migrate to the cortex suggests that this gene uniquely or in combination with other transcription factors may play a role in the neurochemical identity and migration of these neurons. We performed loss of function studies for lhx6 in mouse embryonic day 13.5 brain slices and dissociated MGE neuronal cultures using Lhx6-targeted small interfering RNA produced by a U6 promoter-driven vector. We found that silencing lhx6 impeded the tangential migration of interneurons into the cortex, although it did not obstruct their dispersion within the ganglionic eminence. Blocking lhx6 expression in dissociated MGE cultured neurons did not interfere with the production of GABA or its synthesizing enzyme. These results indicate that lhx6, unlike the closely related member lhx7, does not regulate neurotransmitter choice in interneurons but plays an important role in their migration from the ventral telencephalon to the neocortex

    Algorithms for fitting cylindrical objects to sparse range point clouds for rapid workspace modeling

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    Current methods for construction site modeling employ large, expensive laser range scanners that produce dense range point clouds of a scene from different perspectives. While useful for many purposes, this approach is not feasible for real-time applications, which would enable automated obstacle avoidance and semiautomated equipment control, and could improve both safety and productivity significantly. This paper presents human-assisted rapid environmental modeling algorithms for construction, and focuses on cylindrical object fitting algorithms. The presented algorithms address construction site material of cylindrical shape. Experiments were conducted to determine: (1) the effect of the ratio of length to diameter of the cylinder to the accuracy of the results, (2) the effect of the angle of view to the accuracy of the results, (3) the minimum number of scanned points required to give adequate modeling accuracy for cylinders of various length to diameter ratios. The results indicate that the proposed algorithms can model geometric primitives used in a construction site rapidly and with sufficient accuracy for automated obstacle avoidance and equipment control functions

    Real-Time, Three-Dimensional Object Detection and Modeling in Construction

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    This paper describes a research effort directed to produce methods to model three-dimensional scenes of construction field objects in real-time that adds valuable data to construction information management systems, as well as equipment navigation systems. For efficiency reasons, typical construction objects are modeled by bounding surfaces using a high-frame rate range sensor, called Flash LADAR. The sensor provides a dense cloud of range points which are segmented and grouped into objects. Algorithms are being developed to accurately detect these objects and model characteristics such as volume, speed, and direction. Initial experiments show the feasibility of this method. The advantages and limitations, and potential solutions to limitations are summarized in this paper

    Primitives Merging for Rapid 3D Modeling

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    Developing three dimensional models of infrastructure and construction in progress can be useful for designing modifications, for tracking work completed, and for facilitating advanced equipment control and safety functions. An emerging 3D modeling method involves scanning scenes with laser ranging devices. The resulting dense or sparse point clouds are converted to primitive geometric objects. Merging those objects is useful for visualization and advanced manipulation. Factors that influence this merging process are identified here. Heuristics are proposed for automated merging, and initial results presented

    Tensegrity structures for the Hellenic Maritime Museum

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    p. 2233-2242Tensegrity structures composed of masts and cables bear similarities and carry metaphoric associations to nautical equipment and structures. Such metaphors have suggested the use of the tensegrity concept in the design of the lightweight structures for the Hellenic Maritime Museum. Two different types of lightweight structures have been studied. At an early design stage scaled models of existing tensegrity configurations were considered, and subsequently several new tensegrity configurations have been developed and studied. Morphological variations of tensegrity structures that occur from the assembly of new units have also been studied. A canopy structure composed of prismatic tensegrity units of irregular geometry with an attached membrane and a large space enclosing tensegrity structure have been developed. The paper presents and discusses the configuration of the two tensegrity structures for the maritime museum and the challenges encountered in their geometric & structural design.Liapi, KA. (2010). Tensegrity structures for the Hellenic Maritime Museum. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/727

    Paraneoplastic Cerebellar Ataxia Can Affect Prognosis in High-Grade Serous Ovarian Cancer: A Case Report.

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    The reported case is a 61-year-old woman, admitted for gradual onset of gait disturbances and dysphonia. The serum immunological panel revealed anti-Yo autoantibodies, suggestive of a paraneoplastic syndrome (PNS). A PET-CT revealed a suspicious left ovarian mass with retroperitoneal nodal involvement, and the histological assessment of surgical samples confirmed a FIGO IIIC high-grade serous ovarian cancer (HGSOC). Deemed inoperable at first, the patient was treated by carboplatin and paclitaxel chemotherapy, after which she refused surgical debulking. At the end of her systemic treatment, the patient only experienced a transient improvement of the cerebellar ataxia. Despite the suboptimal oncological treatment, the patient still presents stable disease and is free of progression 7 years from her diagnosis. This case study illustrates the favorable effect of PNS occurrence on oncological outcome in a patient with advanced HGSOC. The absence of recurrence despite the presence of residual disease after the systemic treatment is unusual and could be related to the PNS

    Lymph Node Involvement in Recurrent Serous Borderline Ovarian Tumors: Current Evidence, Controversies, and a Review of the Literature.

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    Borderline ovarian tumors (BOTs) account for 10-20% of epithelial ovarian neoplasms. They are characterized by their lack of destructive stromal invasion. In comparison to invasive ovarian cancers, BOTs occur in younger patients and have better outcome. Serous borderline ovarian tumor (SBOT) represents the most common subtype of BOT. Complete surgical staging is the current standard management but fertility-sparing surgery is an option for SBOT patients who are at reproductive age. While most cases of SBOTs have an indolent course with favorable prognosis, late recurrence and malignant transformation can occur, usually in the form of low-grade serous carcinoma (LGSC). Thus, assessment of the recurrence risk is essential for the management of those patients. SBOTs can be associated with lymph node involvement (LNI) in up to 30% of patients who undergo lymph node dissection at diagnosis, and whether LNI affects prognosis is controversial. The present review suggests that recurrent SBOTs with LNI have poorer oncological outcomes and highlights the biases due to the scarcity of reports in the literature. Preventing SBOTs from recurring and becoming invasive overtime and a more profound understanding of the underlying mechanisms at play are necessary

    VEGFR Inhibitors for Uterine Metastatic Perivascular Epithelioid Tumors (PEComa) Resistant to mTOR Inhibitors. A Case Report and Review of Literature.

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    Uterine perivascular epithelioid cell tumors (PEComas) are rare neoplasms. PI3K/AKT/mTOR pathway upregulation is critical for their pathogenesis and is often associated with TSC1/TSC2 inactivation. Although first line mTOR inhibitors are an effective treatment, metastatic PEComas eventually progress. A 53-year-old woman presented a 4-month history of post-menopausal vaginal bleeding. Clinical and radiological examination detected a uterine mass and a single S1 bone lesion. The patient underwent a radical hysterectomy and bone biopsy. The anatomopathological evaluation concluded to an oligo-metastatic uterine PEComa. The tumor harbored a heterozygous deletion of 9q34 that contains the TSC1 gene. Concerning the primary lesion, the resection was complete and the single bone metastasis was treated with radiotherapy. Three months later, the patient presented bone, lung and subcutaneous metastatic progression. An everolimus and denosumab treatment was initiated. After 2 years of treatment, a clinically significant bone, lung and subcutaneous progression was detected. Following a literature review of the possible therapeutic options, we initiated a second line treatment by pazopanib. This treatment resulted in regression of the subcutaneous lesions and stability of lung and bone metastases. In this challenging, rare setting, our report suggests single agent, anti-angiogenic, tyrosine kinase inhibitor to be effective as second line treatment of metastatic uterine PEComa progressing on mTOR inhibitors
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