2,083 research outputs found

    Pre-implantation mouse embryos cultured In vitro under different oxygen concentrations show altered ultrastructures

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    Abstract Assisted Reproductive Technologies routinely utilize different culture media and oxygen (O2) concentrations to culture human embryos. Overall, embryos cultured under physiological O2 tension (5%) have improved development compared to embryos cultured under atmospheric O2 conditions (20%). The mechanisms responsible for this remain unclear. This study aimed to evaluate the effect of physiologic (5%) or atmospheric O2 (20%) tension on the microscopic ultrastructure of pre-implantation mouse embryos using Transmission Electron Microscopy (TEM). Embryos flushed out of the uterus after natural mating were used as the control. For use as the control, 2-cells, 4-cells, morulae, and blastocysts were flushed out of the uterus after natural fertilization. In vitro fertilization (IVF) was performed using potassium simplex optimized medium (KSOM) under different O2 tensions (5% and 20%) until the blastocyst stage. After collection, embryos were subjected to the standard preparative for light microscopy (LM) and TEM. We found that culture in vitro under 5% and 20% O2 results in an increase of vacuolated shaped mitochondria, cytoplasmic vacuolization and presence of multi-vesicular bodies at every embryonic stage. In addition, blastocysts generated by IVF under 5% and 20% O2 showed a lower content of heterochromatin, an interruption of the trophectodermal and inner cell mass cell membranes, an increased density of residual bodies, and high levels of glycogen granules in the cytoplasm. In conclusion, this study suggests that in vitro culture, particularly under atmospheric O2 tension, causes stage-specific changes in preimplantation embryo ultrastructure. In addition, atmospheric (20%) O2 is associated with increased alterations in embryonic ultrastructure; these changes may explain the reduced embryonic development of embryos cultured with 20% O2

    STUDIO NUMERICO DELL'EMODINAMICA IN PAZIENTI CON DISSECAZIONE AORTICA DI TIPO B

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    The development of type B aortic dissection (AoD) is caused by altered haemodynamic forces exerted on false and true lumina of dissected aorta. This work aims to study haemodynamic and morphological proprieties, which influence the progression or stability of type B AoD. Computational fluid-dynamic analyses were performed on three patients with type B AoD, whose two presented an aneurysm evolution and one presented no further complication connected with dissection. Blood flow features showed that the true lumen flow was laminar and uniform while false lumen flow lost the laminar characteristic with consequent vorticity formation. The entry point zone proximal to the aortic arch showed both high blood velocity and pressure connected with peaks of maximum WSS value. A negative pressure gradient between the false lumen entry and re-entry points was observed. This promotes the blood to flow towards the abdominal aorta reducing the risk of retrograde flow during systole. We concluded that fluid dynamics study of patients with type B AoD is a valid tool to identify the risk of aortic dissection progression as well as the formation of aortic dissection connected pathology

    Evaluation of an integrative approach between HBIM and architecture history

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    Abstract. Restorative and conservative operations of Cultural Heritage buildings involve the historical and objective knowledge of the context. Meaning the knowledge as a diachronic awareness of the history of buildings should help the safeguarding processes of heritage assets.The integration of historical information inside a HBIM platform involves huge benefits for the Cultural Heritage case management, its periodical monitoring operations and valorisation processes, moreover the historical evolution is correctly considered. This solution allows to maximize the comprehension and also communication of the analysed context through few simple steps as visualize, read and query in order to ensure the accuracy and quality of final data (Diara et al, 2018).This new court of methodologic cooperation will be tested on the case study of the medieval Abbey of Staffarda (CN, Italy) and its refectory in a deeper way where, thanks to recent studies, it has been possible to reconstruct analysis map for a complete vision of the church and the Abbey's complex as well (Beltramo et al, 2019).</p

    A COMPARISON BETWEEN 3D RECONSTRUCTION USING NERF NEURAL NETWORKS AND MVS ALGORITHMS ON CULTURAL HERITAGE IMAGES

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    In this research, an innovative comparison between 3D reconstructions obtained by means of Artificial Intelligence, in particular NeRF Neural Networks, and by Structure-from-Motion (SfM) and Multi-View-Stereo (MVS) open-source algorithms is proposed. The 3D reconstruction comparison is performed on two test cases, one of cultural interest, one useful only for technical discussion. It is known that the approaches are traditionally used with different objectives and in different contexts but they can however also be used with similar purpose, i.e., 3D reconstruction. In particular, we were interested in evaluating how NeRF reconstructions are accurate from a metric point of view and how the models obtained from the application of NeRF differ from the model obtained from the classical photogrammetry. By analyzing the results in the considered test cases, we show how NeRF networks, although computationally demanding, can be an interesting alternative or complementary methodology, especially in cases where classical photogrammetric techniques do not allow satisfactory results to be achieved. It is therefore suggested to expand efforts in this direction by exploiting, for example, the numerous improvement proposals of the original NeRF network

    A COMPARISON BETWEEN 3D RECONSTRUCTION USING NERF NEURAL NETWORKS AND MVS ALGORITHMS ON CULTURAL HERITAGE IMAGES

    Get PDF
    In this research, an innovative comparison between 3D reconstructions obtained by means of Artificial Intelligence, in particular NeRF Neural Networks, and by Structure-from-Motion (SfM) and Multi-View-Stereo (MVS) open-source algorithms is proposed. The 3D reconstruction comparison is performed on two test cases, one of cultural interest, one useful only for technical discussion. It is known that the approaches are traditionally used with different objectives and in different contexts but they can however also be used with similar purpose, i.e., 3D reconstruction. In particular, we were interested in evaluating how NeRF reconstructions are accurate from a metric point of view and how the models obtained from the application of NeRF differ from the model obtained from the classical photogrammetry. By analyzing the results in the considered test cases, we show how NeRF networks, although computationally demanding, can be an interesting alternative or complementary methodology, especially in cases where classical photogrammetric techniques do not allow satisfactory results to be achieved. It is therefore suggested to expand efforts in this direction by exploiting, for example, the numerous improvement proposals of the original NeRF network

    Envisioning innovative groundwater management policies through scenario workshops in France and Portugal

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    International audienceIn the Mediterranean basin, climate change is expected to result in reduced available water resources and increased water demand. This will lead to growing competition for the access to scarce water resources. And it will increase environmental pressures exerted on aquatic ecosystems and problems of water resources overexploitation. Groundwater resources could be significantly affected (drop in water tables, sea water intrusion) in particular because their exploitation is often weakly regulated. In this context, policy makers are increasingly enjoined to explore how current groundwater management rules can be adapted. Given the magnitude of predicted hydro-climatic changes, deep institutional, economic and legal changes will be required to take up the challenge of climate change. Policy makers and stakeholders will have to invent a new water management paradigm, calling into question some of the established assumptions, social values and even ideologies. In particular, the role of the State, market forces and collective action in water management will need to be re-examined. In this paper, we argue that the exploration of possible futures should not be conducted by policy makers and experts alone but that it should also involve grass root water users, farmers in particular. We present a participatory foresight methodology which was implemented in two case studies in southern France (Roussillon) and Portugal (Algarve). After describing the methodology, the paper focuses on three contrasted water management scenarios which were discussed with five groups of farmers. It then describes the results obtained, both in terms of ideas related to future water management scenarios and in terms of participatory process

    improving performance of feature extraction in sfm algorithms for 3d sparse point cloud

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    Abstract. The use of Structure-from-Motion algorithms is a common practice to obtain a rapid photogrammetric reconstruction. However, the performance of these algorithms is limited by the fact that in some conditions the resulting point clouds present low density. This is the case when processing materials from historical archives, such as photographs and videos, which generates only sparse point clouds due to the lack of necessary information in the photogrammetric reconstruction. This paper explores ways to improve the performance of open source SfM algorithms in order to guarantee the presence of strategic feature points in the resulting point cloud, even if sparse. To reach this objective, a photogrammetric workflow is proposed to process historical images. The first part of the workflow presents a method that allows the manual selection of feature points during the photogrammetric process. The second part evaluates the metric quality of the reconstruction on the basis of a comparison with a point cloud that has a different density from the sparse point cloud. The workflow was applied to two different case studies. Transformations of wall paintings of the Karanlık church in Cappadocia were analysed thanks to the comparison of 3D model resulting from archive photographs and a recent survey. Then a comparison was performed between the state of the Komise building in Japan, before and after restoration. The findings show that the method applied allows the metric scale and evaluation of the model also in bad condition and when only low-density point clouds are available. Moreover, this tool should be of great use for both art and architecture historians and geomatics experts, to study the evolution of Cultural Heritage

    Envisioning innovative groundwater regulation policies through scenario workshops in France and Portugal

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    Groundwater management policies will need to be revised in many Mediterranean countries, in light of the impact of climate change and the increasing demand for water. In this paper, we analyse stakeholder perceptions of three groundwater policy scenarios which respectively assume a strengthening of state intervention, the introduction of market regulation mechanisms, and the transfer of regulation responsibility to farmers. The method consists of organizing scenario workshops with experts, institutional representatives and farmers. It is applied in two case studies in France and Portugal. From a methodological viewpoint, the research demonstrates farmers’ ability to contribute to an exploratory assessment of possible future water management scenarios. From a policy viewpoint, it clarifies expectations concerning state intervention and self-regulation by farmers. It also provides some insights regarding the acceptability of tradable groundwater permits in two European contexts
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