355 research outputs found

    An Analysis of the Viability of 3D-Printed Construction as an Alternative to Conventional Construction Methods in the Expeditionary Environment

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    Conventional construction is believed by some to have reached its technological limit of performance, making it increasingly difficult for conventional construction methods to meet the U.S. military’s core standards of quality, cost, and timeliness in the expeditionary environment. While still in its infancy, 3D-printed construction has the potential to revolutionize the way the military performs construction in deployed environments. This research conducts a systematic review of the viability of 3D-printed construction to investigate whether or not it is now or could be a viable replacement for conventional construction methods, specifically in remote environments where conventional construction capability may be limited. This research then evaluates seven key viability factors – materials, structural design, process efficiency, logistics, labor, environmental impact, and cost – as they apply to two recent, military-run 3D-printed construction case studies, before drawing conclusions regarding the current viability of 3D-printed construction. Finally, this research suggests areas in which further research and development is needed in order to ensure the effectiveness of 3D-printed construction in the expeditionary environment

    On the use of the OptD method for building diagnostics

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    Terrestrial laser scanner (TLS) measurements can be used to assess the technical condition of buildings and structures; in particular, high-resolution TLS measurements should be taken in order to detect defects in building walls. This consequently results in the creation of a huge amount of data in a very short time. Despite high-resolution measurements typically being needed in certain areas of interest, e.g., to detect cracks, reducing redundant information on regions of low interest is of fundamental importance in order to enable computationally efficient and effective analysis of the dataset. In this work, data reduction is made by using the Optimum Dataset (OptD) method, which allows to significantly reduce the amount of data while preserving the geometrical information of the region of interest. As a result, more points are retained on areas corresponding to cracks and cavities than on flat and homogeneous surfaces. This approach allows for a thorough analysis of the surface discontinuity in building walls. In this investigation, the TLS dataset was acquired by means of the time-of-flight scanners Riegl VZ-400i and Leica ScanStation C10. The results obtained by reducing the TLS dataset by means of OptD show that this method is a viable solution for data reduction in building and structure diagnostics, thus enabling the implementation of computationally more efficient diagnostic strategies

    Study protocol for a prospective, non-controlled, multicentre clinical study to evaluate the diagnostic accuracy of a stepwise two-photon excited melanin fluorescence in pigmented lesions suspicious for melanoma (FLIMMA study)

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    Introduction: Non-invasive, nanosecond, stepwise two-photon laser excitation of skin tissue was shown to induce melanin fluorescence spectra that allow for the differentiation of melanocytic nevi from cutaneous melanoma. Methods and analysis: This prospective, non-controlled, multicentre clinical study is performed to evaluate the diagnostic performance of the stepwise two-photon excited melanin fluorescence in the detection of cutaneous melanoma. The comparator will be the histopathological diagnosis. A total of 620 pigmented skin lesions suspicious for melanoma and intended for excision will be enrolled. Ethics and dissemination: Ethics approval was provided by the local ethics committees of the medical faculties of the University of Tuebingen, Heidelberg and Berlin. Study registration: The FLIMMA study NCT02425475

    Monitoring the correction of glycogen storage disease type 1a in a mouse model using [18F]FDG and a dedicated animal scanner

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    Monitoring gene therapy of glycogen storage disease type 1a in a mouse model was achieved using [18F]FDG and a dedicated animal scanner. The G6Pase knockout (KO) mice were compared to the same mice after infusion with a recombinant adenovirus containing the murine G6Pase gene (Ad-mG6Pase). Serial images of the same mouse before and after therapy were obtained and compared with wild-type (WT) mice of the same strain to determine the uptake and retention of [18F]FDG in the liver. Image data were acquired from heart, blood pool and liver for twenty minutes after injection of [18F]FDG. The retention of [18F]FDG was lower for the WT mice compared to the KO mice. The mice treated with adenovirus-mediated gene therapy had retention similar to that found in age-matched WT mice. These studies show that FDG can be used to monitor the G6Pase concentration in liver of WT mice as compared to G6Pase KO mice. In these mice, gene therapy returned the liver function to that found in age matched WT controls as measured by the FDG kinetics in the liver compared to that found in age matched wild type controlsPublicad

    Lack of neuroinflammation in the HIV-1 transgenic rat: An [18 F]-DPA714 PET imaging study

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    BACKGROUND: HIV-associated neuroinflammation is believed to be a major contributing factor in the development of HIV-associated neurocognitive disorders (HAND). In this study, we used micropositron emission tomography (PET) imaging to quantify neuroinflammation in HIV-1 transgenic rat (Tg), a small animal model of HIV, known to develop neurological and behavioral problems. METHODS: Dynamic [(18)F]DPA-714 PET imaging was performed in Tg and age-matched wild-type (WT) rats in three age groups: 3-, 9-, and 16-month-old animals. As a positive control for neuroinflammation, we performed unilateral intrastriatal injection of quinolinic acid (QA) in a separate group of WT rats. To confirm our findings, we performed multiplex immunofluorescent staining for Iba1 and we measured cytokine/chemokine levels in brain lysates of Tg and WT rats at different ages. RESULTS: [(18)F]DPA-714 uptake in HIV-1 Tg rat brains was generally higher than in age-matched WT rats but this was not statistically significant in any age group. [(18)F]DPA-714 uptake in the QA-lesioned rats was significantly higher ipsilateral to the lesion compared to contralateral side indicating neuroinflammatory changes. Iba1 immunofluorescence showed no significant differences in microglial activation between the Tg and WT rats, while the QA-lesioned rats showed significant activation. Finally, cytokine/chemokine levels in brain lysates of the Tg rats and WT rats were not significantly different. CONCLUSION: Microglial activation might not be the primary mechanism for neuropathology in the HIV-1 Tg rats. Although [(18)F]DPA-714 is a good biomarker of neuroinflammation, it cannot be reliably used as an in vivo biomarker of neurodegeneration in the HIV-1 Tg rat. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12974-015-0390-9) contains supplementary material, which is available to authorized users
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