976 research outputs found

    MicroRNAs regulate Ca2+ homeostasis in murine embryonic stem cells

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    MicroRNAs (miRNAs) are important regulators of embryonic stem cell (ESC) biology, and their study has identified key regulatory mechanisms. To find novel pathways regulated by miRNAs in ESCs, we undertook a bioinformatics analysis of gene pathways differently expressed in the absence of miRNAs due to the deletion of Dicer, which encodes an RNase that is essential for the synthesis of miRNAs. One pathway that stood out was Ca2+ signaling. Interestingly, we found that Dicer-/- ESCs had no difference in basal cytoplasmic Ca2+ levels but were hyperresponsive when Ca2+ import into the endoplasmic reticulum (ER) was blocked by thapsigargin. Remarkably, the increased Ca2+ response to thapsigargin in ESCs resulted in almost no increase in apoptosis and no differences in stress response pathways, despite the importance of miRNAs in the stress response of other cell types. The increased Ca2+ response in Dicer-/- ESCs was also observed during purinergic receptor activation, demonstrating a physiological role for the miRNA regulation of Ca2+ signaling pathways. In examining the mechanism of increased Ca2+ responsiveness to thapsigargin, neither store-operated Ca2+ entry nor Ca2+ clearance mechanisms from the cytoplasm appeared to be involved. Rather, it appeared to involve an increase in the expression of one isoform of the IP3 receptors (Itpr2). miRNA regulation of Itpr2 expression primarily appeared to be indirect, with transcriptional regulation playing a major role. Therefore, the miRNA regulation of Itpr2 expression offers a unique mechanism to regulate Ca2+ signaling pathways in the physiology of pluripotent stem cells

    MicroRNAs control the apoptotic threshold in primed Pluripotent stem cells through regulation of BIM

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    Mammalian primed pluripotent stem cells have been shown to be highly susceptible to cell death stimuli due to their low apoptotic threshold, but how this threshold is regulated remains largely unknown. Here we identify microRNA (miRNA)-mediated regulation as a key mechanism controlling apoptosis in the post-implantation epiblast. Moreover, we found that three miRNA families, miR-20, miR-92, and miR-302, control the mitochondrial apoptotic machinery by fine-tuning the levels of expression of the proapoptotic protein BIM. These families therefore represent an essential buffer needed to maintain cell survival in stem cells that are primed for not only differentiation but also cell death

    MicroRNAs Regulate Ca2+ Homeostasis in Murine Embryonic Stem Cells

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    MicroRNAs (miRNAs) are important regulators of embryonic stem cell (ESC) biology, and their study has identified key regulatory mechanisms. To find novel pathways regulated by miRNAs in ESCs, we undertook a bioinformatics analysis of gene pathways differently expressed in the absence of miRNAs due to the deletion of Dicer, which encodes an RNase that is essential for the synthesis of miRNAs. One pathway that stood out was Ca2+ signaling. Interestingly, we found that Dicer−/− ESCs had no difference in basal cytoplasmic Ca2+ levels but were hyperresponsive when Ca2+ import into the endoplasmic reticulum (ER) was blocked by thapsigargin. Remarkably, the increased Ca2+ response to thapsigargin in ESCs resulted in almost no increase in apoptosis and no differences in stress response pathways, despite the importance of miRNAs in the stress response of other cell types. The increased Ca2+ response in Dicer−/− ESCs was also observed during purinergic receptor activation, demonstrating a physiological role for the miRNA regulation of Ca2+ signaling pathways. In examining the mechanism of increased Ca2+ responsiveness to thapsigargin, neither store-operated Ca2+ entry nor Ca2+ clearance mechanisms from the cytoplasm appeared to be involved. Rather, it appeared to involve an increase in the expression of one isoform of the IP3 receptors (Itpr2). miRNA regulation of Itpr2 expression primarily appeared to be indirect, with transcriptional regulation playing a major role. Therefore, the miRNA regulation of Itpr2 expression offers a unique mechanism to regulate Ca2+ signaling pathways in the physiology of pluripotent stem cells

    4D Reconstruction and Visualization of Cultural Heritage: Analysing our Legacy Through Time

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    Temporal analyses and multi-temporal 3D reconstruction are fundamental for the preservation and maintenance of all forms of Cultural Heritage (CH) and are the basis for decisions related to interventions and promotion. Introducing the fourth dimension of time into three-dimensional geometric modelling of real data allows the creation of a multi-temporal representation of a site. In this way, scholars from various disciplines (surveyors, geologists, archaeologists, architects, philologists, etc.) are provided with a new set of tools and working methods to support the study of the evolution of heritage sites, both to develop hypotheses about the past and to model likely future developments. The capacity to “see” the dynamic evolution of CH assets across different spatial scales (e.g. building, site, city or territory) compressed in diachronic model, affords the possibility to better understand the present status of CH according to its history. However, there are numerous challenges in order to carry out 4D modelling and the requisite multi-data source integration. It is necessary to identify the specifications, needs and requirements of the CH community to understand the required levels of 4D model information. In this way, it is possible to determine the optimum material and technologies to be utilised at different CH scales, as well as the data management and visualization requirements. This manuscript aims to provide a comprehensive approach for CH time-varying representations, analysis and visualization across different working scales and environments: rural landscape, urban landscape and architectural scales. Within this aim, the different available metric data sources are systemized and evaluated in terms of their suitability

    Average Entropy of a Subsystem from its Average Tsallis Entropy

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    In the nonextensive Tsallis scenario, Page's conjecture for the average entropy of a subsystem[Phys. Rev. Lett. {\bf 71}, 1291(1993)] as well as its demonstration are generalized, i.e., when a pure quantum system, whose Hilbert space dimension is mnmn, is considered, the average Tsallis entropy of an mm-dimensional subsystem is obtained. This demonstration is expected to be useful to study systems where the usual entropy does not give satisfactory results.Comment: Revtex, 6 pages, 2 figures. To appear in Phys. Rev.

    The Pioneer anomaly in the context of the braneworld scenario

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    We examine the Pioneer anomaly - a reported anomalous acceleration affecting the Pioneer 10/11, Galileo and Ulysses spacecrafts - in the context of a braneworld scenario. We show that effects due to the radion field cannot account for the anomaly, but that a scalar field with an appropriate potential is able to explain the phenomena. Implications and features of our solution are analyzed.Comment: Final version to appear at Classical & Quantum Gravity. Plainlatex 19 page

    EP05.02-003 Durvalumab after Chemoradiotherapy (CRT) in Unresectable Stage III NSCLC. Comparative Study of Two Cohorts in the Real-World Setting

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    [EN] Introduction: Durvalumab is the new standard of care for unresectable locally advanced NSCLC, with PD-L1 _1% and who did not have progression after CRT treatment in the European Union. Our study compares the effectiveness and the frequency of radiation pneumonitis in patients treated with concurrent CRT with or without durvalumab consolidation during the same period in real clinical practice. Methods: A single-center retrospective study. 71 treated patients with unresectable stage III NSCLC were included between March 2018 and December 2021, 37 with CRT followed by durvalumab and 34 with CRT alone. Real-world progression-free survival (rwPFS) and real-world overall survival (rwOS) were calculated since the date of the end CRT. Propensity score matching (PSM) 1:1 was used to account for differences in baseline characteristics. Results: Median age was 67 years (range 46-82). 25.4% of the patients were _75 years old. 78.9% were men and 53.5% former smokers. 54.9% had squamous histology and 28%, 51% and 21% stage IIIA, IIIB and IIIC disease, respectively. The most used scheme was carboplatinpaclitaxel (43.7%), receiving induction chemotherapy in up to 54.9% of patients. 73.2% received between 60-66 Gy doses of radiotherapy. Median time from end of CRT to onset durvalumab was 44 days (range 13-120) with a median of 14 infusions (range 6-27). Of the 34 patients without durvalumab treatment, the expression PD-L1 <1% (58.8%) was the most frequent cause for rejecting consolidation therapy. After PSM analysis, patients distributions were well balanced. With a median follow-up of 19.7 months (range 1.4-36.6); median rw-PFS was 9.3 months (95% CI, 5-13.5) without durvalumab and 17 months (95% CI, 11-22.9) with durvalumab (p¼0.013). Median rw-OS was 19.3 months (95% CI, 3.8-34.8) without durvalumab and 29.9 months (95% CI, 23.3-36.6) with durvalumab (p¼0.241) with a rw-OS% at 6, 18 and 24 months of 90%, 62% and 49% vs 100%, 86% and 74%, respectively. The rate of radiation pneumonitis was more frequent with durvalumab consolidation (56.8% against 44.1%), (p¼0.346), especially within 3 months after CRT. G3 pneumonitis was only observed in the consolidation therapy. Conclusions: Our results demonstrate the effectiveness of durvalumab consolidation after CRT in real-world patients with unresectable stage III NSCLC. Further sample and longer follow-up are required to obtain more accurate results. Active surveillance and appropriate management for radiation pneumonitis are needed, in especially in candidates for consolidation treatmentS

    EP05.02-002 Who Benefits More of Durvalumab after Chemoradiotherapy (CRT) in Real-World Patients with Locally Advanced Non-Small-Cell Lung Cancer (NSCLC)?

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    [EN] Introduction: Durvalumab received EMA approval as consolidation therapy (CT) for unresectable stage III NSCLC with PD-L1 _1% and who did not have progression after CRT. Our objective was to analyze in real clinical practice the effectiveness of durvalumab and explore the clinical factors that may be associated with the benefit from CT. Methods: Retrospective study was made at Hospital of Leon (Spain), including 37 patients with locally advanced NSCLC treated with durvalumab after CRT treatment between March 2018 and october 2021 (40.5% patients were included in the durvalumab early access program). The neutrophil-to-lymphocyte ratio (NLR) could identified after CRT as a factor that may be benefit from durvalumab. Results: Median age was 67 years (range 46-82 years). 40.5% of patients were _70 years old. 78.4% were male and 51.4% smokers. 54% had non-squamous histology. PD-L1 expression was <1% in 5% and not available in 8% patients. 2.7% ROS1 rearrangements, 5.4% KRAS mutations and not available in 43.2% patients. Stage IIIA, IIIB, IIIC disease were 24.3%, 54.1% and 21.6%, respectively. Median time from end of CRT to onset durvalumab was 44 days (range 13-120 days). Overall median CT duration was 214.8 days (range 69-399 days) with a median of 14 infusions (range 6-27 infusions). With a median follow up of 19.7 months (range 1.4-34.9 months); 67.6% had stopped CT: 37.8% due to completing treatment, 16.2% disease progression, 10.8% adverse event and 2.7% due to COVID19 infection. Median real-world progressionfree survival (rwPFS) was 17 months (95% CI, 11-23). Median realworld overall survival (rwOS) was 29.9 months (95% CI, 23.3-36.6). % rwOS at 6, 18 and 24 months were 100%, 86.9% and 74.5%, respectively. For patients with post-CRT NLR not exceeding the cohort median value of 6, receipt of durvalumab was associated with an improvement in rwOS (median not reached vs 25.7 months; p¼0.025). 56.8% patients had any grade of radiation pneumonitis (median time from CRT start: 119 days [range 36-241 days]). Of these, 19% patients developed worsening of radiation pneumonitis with durvalumab. 54,1% developed immune-mediated toxicity, mostly G1-2 (85.1%). Conclusions: Our results demonstrate the effectiveness of durvalumab consolidation in this patients population in a real-life setting. We identified low NLR after CRT as a potentially predictive factor for the benefit of CT in locally advanced NSCLC.S

    The LHCb Silicon Inner Tracker

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    The inner part of the LHCb main tracking system will be realized in a silicon microstrip technology. The experimental requirements suggest approximately 20 cm-long ladders and a readout pitch of around 200 m. The LHCb Inner Tracker system will consist of three tracking stations having a total of 12 detection layers summing to an overall silicon surface area of approximately 4.2 m2. A report about the status of the current R&D of the silicon ladders and tracking stations of the LHCb Inner Tracker is given
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