239 research outputs found

    Good Transport Practices in University of West Attica

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    University of West Attica operates in three Campuses, all within the metropolitan region of Attica, indicating that the mobility characteristics of these campuses are similar to urban models and in most cases, could be used as a test area for mobility policies related to public transport, multimodality or transport restrictions. Within the Cοvid-19 period, University of West Attica made important progress in transport related issues that are very critical for the smooth operation of the campuses and the University as a whole. The key transport related good practices refer to several thematic areas including parking management, soft modes infrastructure, public transport, car related issues, road infrastructure, environment, and energy. All these key interventions have a positive impact not only for the members of the academic society of University of West Attica but also to the mobility characteristics of West and Central Attica where university campuses are located and interact with Attica residents and tourists.Keyword: University of West Attica, Campus, Urban Mobility, Transport, Parkin

    Coupling curvature-dependent and shear stress-stimulated neotissue growth in dynamic bioreactor cultures: a 3D computational model of a complete scaffold.

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    The main challenge in tissue engineering consists in understanding and controlling the growth process of in vitro cultured neotissues toward obtaining functional tissues. Computational models can provide crucial information on appropriate bioreactor and scaffold design but also on the bioprocess environment and culture conditions. In this study, the development of a 3D model using the level set method to capture the growth of a microporous neotissue domain in a dynamic culture environment (perfusion bioreactor) was pursued. In our model, neotissue growth velocity was influenced by scaffold geometry as well as by flow- induced shear stresses. The neotissue was modeled as a homogenous porous medium with a given permeability, and the Brinkman equation was used to calculate the flow profile in both neotissue and void space. Neotissue growth was modeled until the scaffold void volume was filled, thus capturing already established experimental observations, in particular the differences between scaffold filling under different flow regimes. This tool is envisaged as a scaffold shape and bioprocess optimization tool with predictive capacities. It will allow controlling fluid flow during long-term culture, whereby neotissue growth alters flow patterns, in order to provide shear stress profiles and magnitudes across the whole scaffold volume influencing, in turn, the neotissue growth

    Incorporating Quality In Engineered Tissues Using Bottom-Up Niche Assemblies

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    A major limitation in Tissue Engineering (TE) is the ability to control complexity within 3D engineered constructs. Diffusion limitations lead to the development of uncontrolled or even adverse environments leading to uncontrolled stem cell fate decision within the cultured tissue and cell death. Moreover the lack of control of the environment within these constructs makes the application of quality engineering principles such as quality by design (QbD) impossible. Length-scales chosen for the creation of in vitro tissues have not been chosen based on rational criteria and hence minimal success has been attained upon implantation. Recently bottom-up strategies have been introduced advocating the use of smaller tissue modules as building blocks for the formation of larger tissues prior to implantation. In this work we first cultured seeded human progenitor cells on non-adherent agarose surfaces containing microwells at their bottom, trapping the seeded cells, allowed initial condensations to take place and the formation of controlled-size aggregates (Figure 1A). After chondrogenic differentiation 3D cartilage intermediate µ-tissues where formed, positive for alcian blue and safranin-o stains indication the presence of mature cartilaginous extracellular matrix. These cartilaginous µ-tissues were fused via self-assembly for 24 hrs in vitro into larger implants with a diameter of 4 mm and implanted subcutaneously in small animal models. As control we used implants formed by progenitor cells cultured in pellet format in the same media formulation as the µ-tissues and containing the same amount of cells as the bottom-up assembled implant. Even at this scale a bone organ was formed in vivo containing a cortex and a bone marrow compartment while the macro-pellet demonstrated a large fibrotic tissue domain within the implant (Figure 1B, C). Please click Additional Files below to see the full abstract

    Visual Speech-Aware Perceptual 3D Facial Expression Reconstruction from Videos

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    The recent state of the art on monocular 3D face reconstruction from image data has made some impressive advancements, thanks to the advent of Deep Learning. However, it has mostly focused on input coming from a single RGB image, overlooking the following important factors: a) Nowadays, the vast majority of facial image data of interest do not originate from single images but rather from videos, which contain rich dynamic information. b) Furthermore, these videos typically capture individuals in some form of verbal communication (public talks, teleconferences, audiovisual human-computer interactions, interviews, monologues/dialogues in movies, etc). When existing 3D face reconstruction methods are applied in such videos, the artifacts in the reconstruction of the shape and motion of the mouth area are often severe, since they do not match well with the speech audio. To overcome the aforementioned limitations, we present the first method for visual speech-aware perceptual reconstruction of 3D mouth expressions. We do this by proposing a "lipread" loss, which guides the fitting process so that the elicited perception from the 3D reconstructed talking head resembles that of the original video footage. We demonstrate that, interestingly, the lipread loss is better suited for 3D reconstruction of mouth movements compared to traditional landmark losses, and even direct 3D supervision. Furthermore, the devised method does not rely on any text transcriptions or corresponding audio, rendering it ideal for training in unlabeled datasets. We verify the efficiency of our method through exhaustive objective evaluations on three large-scale datasets, as well as subjective evaluation with two web-based user studies

    Interactive visualization of cell expansion process performance

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    As cell-based technologies are rapidly evolving beyond the laboratory scale, the demand for mass production of high quality cells is increasing. Unfortunately, only limited amounts of cells can be sourced from (human) donors. Therefore sequences of cell expansion steps are required to multiply the original number of cells taken from the donor biopsy to the amounts required for clinical application. Currently a large variety of expansion processes are used and described in literature. However, it is extremely difficult to compare them as many mesenchymal stem cell (MSC) subtypes are used in different culture vessels, with different medium compositions, etc. Moreover, adding to this variation in expansion strategies, within one process there can be significant fluctuations in outcome due to process variability and inherent donor-to-donor related variability. The aim of this work was to analyze the performance of a range of expansion processes for large-scale MSC expansion. Therefore a literature-based study was performed, currently resulting in a database of 73 individual cell expansion processes in 5 different types of culture vessels (microcarrier, (layered) flasks, hollow fiber-, multiplate-, and packed bed-bioreactor), 6 different types of MSCs and many different media compositions. The scale of the processes in terms of final cell numbers ranged between 7.5x106 and 1.1x1010 cells. An interactive process map was created where the scale, efficiency, cell type, culture method and load on downstream processing can be explored (see figure below). This interactive visualization tool provides an integrated perspective on the different culture processes and is able to increase the understanding on process comparability, attainable cell yield, scale-up strategies and the effect of certain critical process parameters on the expansion result. Please click Additional Files below to see the full abstract

    Imaging in situ breast carcinoma (with or without an invasive component) with technetium-99m pentavalent dimercaptosuccinic acid and technetium-99m 2-methoxy isobutyl isonitrile scintimammography

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    INTRODUCTION: The aim of the study was to retrospectively define specific features of the technetium-99m pentavalent dimercaptosuccinic acid ((99m)Tc-(V)DMSA) and technetium-99m 2-methoxy isobutyl isonitrile ((99m)Tc-Sestamibi [(99m)Tc-MIBI]) distribution in ductal breast carcinoma in situ and lobular breast carcinoma in situ (DCIS/LCIS), in relation to mammographic, histological and immunohistochemical parameters. MATERIALS AND METHODS: One hundred and two patients with suspicious palpation or mammographic findings were submitted preoperatively to scintimammography (a total of 72 patients with (99m)Tc-(V)DMSA and a total of 75 patients with (99m)Tc-Sestamibi, 45 patients receiving both radiotracers). Images were acquired at 10 min and 60 min, and were evaluated for a pattern of diffuse radiotracer accumulation. The tumor-to-background ratios were correlated (T-pair test) with mammographic, histological and immunohistochemical characteristics. RESULTS: Histology confirmed malignancy in 46/102 patients: 20/46 patients had DCIS/LCIS, with or without coexistent invasive lesions, and 26/46 patients had isolated invasive carcinomas. Diffuse (99m)Tc-(V)DMSA accumulation was noticed in 18/19 cases and (99m)Tc-Sestamibi in 6/13 DCIS/LCIS cases. Epithelial hyperplasia demonstrated a similar accumulation pattern. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value for each tracer were calculated. Solely for (99m)Tc-(V)DMSA, the tumor-to-background ratio was significantly higher at 60 min than at 10 min and the diffuse uptake was significantly associated with suspicious microcalcifications, with the cell proliferation index ≥ 40% and with c-erbB-2 ≥ 10%. CONCLUSION: (99m)Tc-(V)DMSA showed high sensitivity and (99m)Tc-Sestamibi showed high specificity in detecting in situ breast carcinoma ((99m)Tc-(V)DMSA especially in cases with increased cell proliferation), and these radiotracers could provide clinicians with preoperative information not always obtainable by mammography

    Software for full-color 3D reconstruction of the biological tissues internal structure

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    A software for processing sets of full-color images of biological tissue histological sections is developed. We used histological sections obtained by the method of high-precision layer-by-layer grinding of frozen biological tissues. The software allows restoring the image of the tissue for an arbitrary cross-section of the tissue sample. Thus, our method is designed to create a full-color 3D reconstruction of the biological tissue structure. The resolution of 3D reconstruction is determined by the quality of the initial histological sections. The newly developed technology available to us provides a resolution of up to 5 - 10 {\mu}m in three dimensions.Comment: 11 pages, 8 figure

    Human Platelet Lysate Improves Bone Forming Potential of Human Progenitor Cells Expanded in Microcarrier-Based Dynamic Culture.

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    Xenogeneic-free media are required for translating advanced therapeutic medicinal products to the clinics. In addition, process efficiency is crucial for ensuring cost efficiency, especially when considering large-scale production of mesenchymal stem cells (MSCs). Human platelet lysate (HPL) has been increasingly adopted as an alternative for fetal bovine serum (FBS) for MSCs. However, its therapeutic and regenerative potential in vivo is largely unexplored. Herein, we compare the effects of FBS and HPL supplementation for a scalable, microcarrier-based dynamic expansion of human periosteum-derived cells (hPDCs) while assessing their bone forming capacity by subcutaneous implantation in small animal model. We observed that HPL resulted in faster cell proliferation with a total fold increase of 5.2 +/- 0.61 in comparison to 2.7 +/- 02.22-fold in FBS. Cell viability and trilineage differentiation capability were maintained by HPL, although a suppression of adipogenic differentiation potential was observed. Differences in mRNA expression profiles were also observed between the two on several markers. When implanted, we observed a significant difference between the bone forming capacity of cells expanded in FBS and HPL, with HPL supplementation resulting in almost three times more mineralized tissue within calcium phosphate scaffolds. FBS-expanded cells resulted in a fibrous tissue structure, whereas HPL resulted in mineralized tissue formation, which can be classified as newly formed bone, verified by muCT and histological analysis. We also observed the presence of blood vessels in our explants. In conclusion, we suggest that replacing FBS with HPL in bioreactor-based expansion of hPDCs is an optimal solution that increases expansion efficiency along with promoting bone forming capacity of these cells. Stem Cells Translational Medicine 2019
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