230 research outputs found

    ROCOV scheme for Fault Detection and Location in HVDC sytems

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    A reliable DC fault protection system is essential for the development of HVDC grids. Therefore, this paper deals with the voltage derivative ROCOV scheme to locate and detect DC faults. The algorithm is able to differentiate internal and external faults considerably fast. The proposed algorithm is analyzed in a HVDC grid with different fault case scenarios. Finally, the ROCOV protection thresholds are discussed.The authors thank the support from the Spanish Ministry of Economy, Industry and Competitiveness (project ENE2016-79145-R AEI/FEDER, UE) and GISEL research group IT1083-16), as well as from the University of the Basque Country UPV/EHU (research group funding PPG17/23)

    Katamar lekualdatzetik, ibiltzera. Garapen motor autonomoa biziaren bigarren urtean

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    [EUS] Haurraren garapen motor autonomoa errespetatu eta honetarako baldintza egokiak ematen direnean, haurrek buruz gorako posturatik ibiltzera artekoak berezko zenari jarraituz garatzen dituzte, Pikler-Lóczyko ereduan ikus daitekeen moduan. Lóczyko haurren garapen autonomoaren bilakaera eredutzat hartuz katamar lekualdatzetik ibiltzerako tartean dauden gure haur eskolako hiru haurren mugimendu eta posturak aztertzea izan da lan honen helburua. Emaitzek agerian uzten dute haur hauek joera naturala jarraitu eta zenbait mugimendu eta postura automatizatzeko bidean egon arren, ez direla Pikler-Lóczyko haurren berak izan; gai izan baino lehen bertikalizatutako haurrak izan daitezkeela eta beraien garapen motorra ez dela errespetatua izan.[ES] Cuando se respeta el desarrollo motor autónomo del niño o la niña y se dan las condiciones adecuadas para ello, los niños y las niñas desarrollan desde la posición de boca arriba hasta la posición de marcha siguiendo la tendencia natural, como se puede ver en el modelo de Pikler-Lóczy. El objetivo de este trabajo ha sido analizar los movimientos y las posturas de tres niños y niñas de nuestra escuela infantil tomando como modelo la evolución del desarrollo autónomo Pikler-Lóczy. Los resultados evidencian que aunque estos niños siguen la tendencia natural y están en camino de automatizar ciertos movimientos y posturas, no han sido los obtenidos por Pikler-Lóczy y que por tanto pueden haber sido niños verticalizados precozmente, niños cuyo desarrollo motor autónomo no se ha respetado.[EN] When the autonomous motor development of the child is respected and the appropriate conditions are provided, children develop from the prone position to the walking position following the natural tendency, as can be seen in the Pikler-Lóczy model. The aim of this work has been to analyse the movements and postures of three infant school children taking the Pikler-Lóczy model of autonomous development as a model. The results show that although these children follow the natural tendency and are on the way to automate certain movements and postures, they are not the same as obtained by Pikler-Lóczy and therefore may have been precociously verticalized children, children whose autonomous motor development has not been respected

    Testing the Verification and Validation Capability of a DCP-Based Interface for Distributed Real-Time Applications

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    Cyber–physical systems (CPS) integrate diverse elements developed by various vendors, often dispersed geographically, posing significant development challenges. This paper presents an improved version of our previously developed co-simulation interface based on the non-proprietary Distributed Co-Simulation Protocol (DCP) standard, now optimized for broader hardware platform compatibility. The core contributions include a demonstration of the interface’s hardware-agnostic capabilities and its straightforward adaptability across different platforms. Furthermore, we provide a comparative analysis of our interface against the original DCP. It is validated via various X-in-the-Loop simulations, reinforcing the interface’s versatility and applicability in diverse scenarios, such as distributed real-time executions, verification and validation processes, or Intellectual Property protection.This research was funded by Basque Government through the ELKARTEK programme under the AUTOTRUS project (grant number KK-2023/00019) and the European Commission’s Horizon Europe programme under the METASAT project (grant 101082622)

    Bioengineering of Humanized Bone Marrow Microenvironments in Mouse and Their Visualization by Live Imaging

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    Human hematopoietic stem cells (HSCs) reside in the bone marrow (BM) niche, an intricate, multifactorial network of components producing cytokines, growth factors, and extracellular matrix. The ability of HSCs to remain quiescent, self-renew or differentiate, and acquire mutations and become malignant depends upon the complex interactions they establish with different stromal components. To observe the crosstalk between human HSCs and the human BM niche in physiological and pathological conditions, we designed a protocol to ectopically model and image a humanized BM niche in immunodeficient mice. We show that the use of different cellular components allows for the formation of humanized structures and the opportunity to sustain long-term human hematopoietic engraftment. Using two-photon microscopy, we can live-image these structures in situ at the single-cell resolution, providing a powerful new tool for the functional characterization of the human BM microenvironment and its role in regulating normal and malignant hematopoiesis

    Modeling the human bone marrow niche in mice: From host bone marrow engraftment to bioengineering approaches

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    Xenotransplantation of patient-derived samples in mouse models has been instrumental in depicting the role of hematopoietic stem and progenitor cells in the establishment as well as progression of hematological malignancies. The foundations for this field of research have been based on the development of immunodeficient mouse models, which provide normal and malignant human hematopoietic cells with a supportive microenvironment. Immunosuppressed and genetically modified mice expressing human growth factors were key milestones in patient-derived xenograft (PDX) models, highlighting the importance of developing humanized microenvironments. The latest major improvement has been the use of human bone marrow (BM) niche-forming cells to generate human-mouse chimeric BM tissues in PDXs, which can shed light on the interactions between human stroma and hematopoietic cells. Here, we summarize the methods used for human hematopoietic cell xenotransplantation and their milestones and review the latest approaches in generating humanized BM tissues in mice to study human normal and malignant hematopoiesis

    Low molecular weight poly((d,l)-lactide-co-caprolactone) liquid inks for diluent-free DLP printing of cell culture platforms

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    Digital light processing (DLP) printing offers the possibility of fabricating complex objects in a fast and reproducible manner. A main requirement for DLP printing is the use of inks with low viscosities that can flow under the printing platform in a short period of time. Its exploitation in tissue engineering applications has been centered on the use of hydrogel forming materials diluted in aqueous solutions or the use of polyesters in combination with diluents and heating platforms that aid in the reduction of their viscosity. The use of diluents, however, modifies the mechanical properties and reduces the shape fidelity of the printed objects and, the use of heating platforms results in vats with heterogeneous temperatures and ink viscosities. Here, we report on the synthesis of a library of methacrylated low molecular weight (<3000 g mol−1) homopolymers ((P(D,L)LA and PCL) and copolymers (P((D,L)LA-co-CL)) of 2- and 3-arms based on (D,L)-lactide and ε-caprolactone. The resulting inks possessed low viscosity that made them printable in the absence of diluents and heating elements. DLP printing of cubical and cylindrical patterns resulted in objects with a higher shape fidelity than their counterparts fabricated using diluents and with printed features on the order of 300 μm. The printed materials were biocompatible and supported the growth of human mesenchymal stem cells (hMSCs). Moreover, the variations in the composition resulted in polymers that enabled the attachment of hMSCs to different extents, leading to the formation of well-adhered cell monolayers or loosely adhered cell aggregates.The authors acknowledge the funding bodies and support through the EMAKIKER grant. S. C.-E. acknowledges the Spanish Ministry of Science and Innovation (MICINN) – State Investigation Agency (AEI) (PID2020-114901RA-I00). S. C.-E. and S. R.-D. acknowledge the Basque Government (PIBA_2022_1_0006). G. L.-J. acknowledges the Basque Government Predoctoral grant PRE_2021_1_0403. S. C.-E. and L. I. acknowledge the Provincial Council of Guipuzcoa. The project that gave rise to these results received the support of a fellowship from the “laCaixa” Foundation (ID100010434). The fellowship code is 117145. S. C.-E. acknowledges funding from the University of the Basque Country UPV/EHU within the framework of Grupos de Investigación (GIU21/033). A. A. acknowledges funding from PID2021-127191OB-I00 and RTI2018-101708-A-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. Grant RYC2018-025502-I funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”

    Circuit Breaker Failure Protection Strategy for HVDC Grids

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    HVDC grids demand the fast and reliable operation of the protection system. The failure of any protection element should initialize a backup protection almost immediately in order to assure the system’s stability. This paper proposes a novel backup strategy that covers the failure of the primary protection including the malfunctioning of the HVDC circuit breaker. Only local voltage measurements are employed in the proposed backup protection and the voltage derivative is calculated at both sides of the limiting inductor. Consequently, the speed and reliability of the protection system are enhanced, since no communication channel is needed. This paper contains a thorough specification of the proposed protection strategy. This strategy is validated in a four-terminal HVDC grid with various fault case scenarios, including high-resistance fault cases. The operation of the backup protection is reliable and remarkably fast.This research was funded by the Basque Government (GISEL research group IT1191-19) and the University of the Basque Country UPV/EHU (GISEL research group 181/18 and PIF20/06)

    Assessment of the operational flexibility of virtual power plants to facilitate the integration of distributed energy resources and decision-making under uncertainty

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    Distributed energy resources (DERs) are elements that actively participate in the supply of renewable energy and contribute to the decarbonization of the power system. However, they lack two factors necessary to take advantage of their operational flexibility: observability and controllability. In this sense, Virtual Power Plants (VPPs) are a feasible alternative to provide the necessary requirements for the optimal management of a set of distributed units. Therefore, knowledge of the technical and energy characteristics of each unit that makes up the VPP is a necessary condition for the effective integration of DERs into the power system. This paper proposes a methodology to graphically represent, quantify and exploit the aggregate operational flexibility of a set of units. The proposed methodology is based on five metrics related to active and reactive power, which serve as a tool to facilitate the VPP Operator's decision-making under uncertainty. Consequently, achieving the coordinated operation of several distributed units makes it possible to achieve common objectives. For instance, frequency and voltage regulation, compliance with a planned power curve, or dealing with the variability of renewable energies. The proposal is applied to a theoretical case study and through real operational tests between a hydroelectric unit and a photovoltaic plant. Finally, it is shown that the results obtained are a useful tool in real-time.The authors acknowledge the support from GISEL research group IT1191-19, as well as from the University of the Basque Country UPV/EHU (research group funding 181/18)

    Tissue-Specific Decellularization Methods: Rationale and Strategies to Achieve Regenerative Compounds

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    The extracellular matrix (ECM) is a complex network with multiple functions, including specific functions during tissue regeneration. Precisely, the properties of the ECM have been thoroughly used in tissue engineering and regenerative medicine research, aiming to restore the function of damaged or dysfunctional tissues. Tissue decellularization is gaining momentum as a technique to obtain potentially implantable decellularized extracellular matrix (dECM) with well-preserved key components. Interestingly, the tissue-specific dECM is becoming a feasible option to carry out regenerative medicine research, with multiple advantages compared to other approaches. This review provides an overview of the most common methods used to obtain the dECM and summarizes the strategies adopted to decellularize specific tissues, aiming to provide a helpful guide for future research development.This work was supported by the Spanish “Programa Estatal de I+D+i Orientada a los Retos de la Sociedad”, grant number RTI2018-101708-A-I00. S.R.-C. was supported by Fomento de San Sebastian innovative talent programme, grant number 0508/2019/0009. R.R.-H. was supported by Spanish State Training Subprogramme, grant number PRE2018-084542. A.A. was supported by Spanish State Subprogramme of Incorporation Ramón y Cajal, grant number RYC2018-025502-I, and 2019 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation, grant number IN[19]_CMA_BIO_0119

    Clonal dynamics in osteosarcoma defined by RGB marking

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    Osteosarcoma is a type of bone tumour characterized by considerable levels of phenotypic heterogeneity, aneuploidy, and a high mutational rate. The life expectancy of osteosarcoma patients has not changed during the last three decades and thus much remains to be learned about the disease biology. Here, we employ a RGB-based single-cell tracking system to study the clonal dynamics occurring in a de novo-induced murine osteosarcoma model. We show that osteosarcoma cells present initial polyclonal dynamics, followed by clonal dominance associated with adaptation to the microenvironment. Interestingly, the dominant clones are composed of subclones with a similar tumour generation potential when they are re-implanted in mice. Moreover, individual spontaneous metastases are clonal or oligoclonal, but they have a different cellular origin than the dominant clones present in primary tumours. In summary, we present evidence that osteosarcomagenesis can follow a neutral evolution model, in which different cancer clones coexist and propagate simultaneously.We thank ISCIII and CNIO flow cytometry and cell sorting units for their participation in our studies. We are thankful to the CCEH-Fred Hutchinson Cancer Research Center for LAM-PCR service. We acknowledge Raquel Pérez Tavarez, María Blázquez Mesa, Alicia Giménez Sánchez, Elena Calvo Cazalilla, and Monserrat Arroyo Correas for useful help on the pathology studies; and Teresa Cejalvo, Isabel Cubillo Moreno, and Miguel Angel Rodríguez-Milla for their contributions in experimental setup. We thank the visual artist Isabella Lacquaniti for her help with drawings and schematics. We are also thankful to the Fondo de Investigaciones Sanitarias (FIS: PI11/00377 and PI14CIII/00005 to J.G.-C., FIS: CP11/00206 to A.A., and RTICC: RD12/0036/0027 to J.G.-C.), the Madrid Regional Government (CellCAM; P2010/BMD-2420 to J.G.-C.), the Asociación Pablo Ugarte, and the Asociación Afanion for grants support.S
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