1,774 research outputs found
The Normal and Fibrotic Mouse Lung in Situ Classified by High Dimensional Single Cell Analysis on Routinely Processed Tissue
No full textStudio delle Popolazioni Stellari Multiple nell' Ammasso Globulare NGC 6723
No full textFino a pochi anni fa, si credeva che gli ammassi globulari fossero l'esempio per antonomasia di “popolazione stellare semplice”, ovvero stelle formatesi allo stesso momento e aventi le stesse proprietà chimiche. La scoperta di sequenze multiple nei diagrammi colore-magnitudine di quasi tutti gli ammassi globulari della Galassia, ci ha fatto capire che questi oggetti non sono formati da una singola popolazione, ma ospitano diverse popolazioni stellari caratterizzate da proprietà chimiche diverse. Queste variazioni chimiche sono differenti da ammasso ad ammasso e sono la prova che sulla superficie delle stelle degli ammassi è presente materiale che è stato prodotto dal bruciamento dell’idrogeno ad alte temperature.
In questo lavoro ho analizzato le popolazioni stellari multiple nell’ammasso globulare NGC 6723, perché presenta delle caratteristiche molto particolari che pochi altri ammassi posseggono. Infatti come mostrato in Milone et al. (2017) nella mappa cromosomica (un particolare diagramma due colori) le popolazioni multiple di NGC 6723 si distribuiscono in due gruppi principali, corrispondenti a due generazioni distinte di stelle. La ulteriore peculiarità sta nel fatto che la prima generazione sembra sia formata a sua volta da due differenti popolazioni.
Le immagini utilizzate in questo lavoro di analisi delle popolazioni stellari multiple ospitate dall’ammasso globulare NGC 6723, fanno parte dei progetti “ACS Survey of Galactic Globular Clusters” (GO-10775, P.I.: A. Sarajedini) e “The HST UV Legacy Survey of Galactic Globular Clusters” (GO-13297, P.I.: G. Piotto) e sono state acquisite con l’utilizzo del telescopio spaziale HST. Ho ridotto tutti i dati HST utilizzando un software all'avanguardia, che mi ha permesso di ricavare fotometria e strometria di alta precisione anche per stelle localizzate in ambienti affollati come quelli degli ammassi globulari. Ho quindi stilato un catalogo astro-fotometrico di NGC6723, sul quale ho eseguito la mia analisi.
Combinando magnitudini in bande UV ( nei filtri F275W, F336W e F438W) e in bande ottiche (filtri F606W e F814W) presenti nel mio catalogo, ho ricavato diagrammi (pseudo)colore-magnitudine, diagrammi due colori e mappe cromosomiche, con lo scopo di massimizzare la separazione tra le diverse sequenze delle diverse popolazioni.
Grazie alla fotometria di alta precisione sono riuscito ad individuare almeno 5 distinte popolazioni stellari: tre di queste appartengono alla cosiddetta Seconda Generazione (SG) e due (almeno) alla Prima Generazione di stelle. Ho trovato che lungo l’RGB le due generazioni di stelle non hanno una dipendenza dalla magnitudine, escludendo dunque l’esistenza di un legame tra le diverse generazioni con la fase evolutiva. Nel ri-mappare le popolazioni nei CMDs ho avuto la conferma che la prima generazione di stelle è composta da due popolazioni indipendenti. La seconda generazione di stelle si inverte invece con la prima nei CMDs che usano colori UV . Le popolazioni intermedie (di seconda generazione) sembrano avere delle sostanziali differenze di azoto rispetto alle stelle di prima generazione.
I dati spettroscopici di NGC 6723 presenti in letteratura confermano in modo convincente la classificazione delle diverse popolazioni stellari che ho ricavato, ovvero che le stelle di prima generazione sono povere di azoto e sodio e ricche e di carbonio e ossigeno, mentre le stelle di seconda generazione sono ricche di sodio e povere di carbonio e ossigeno.
I risultati ottenuti forniscono nuovi vincoli agli scenari di formazione, che per ora non risultano ancora completi nel descrivere tutte le caratteristiche osservative delle popolazioni stellari multiple. Solo un’analisi completa di questo tipo svolta su tutti gli ammassi globulari riuscirà a dare dei vincoli più stringenti agli scenari di formazione e alla comprensione dei meccanismi che regolano tali processi.ope
Generation and Characterization of the First Immortalized Alpaca Cell Line Suitable for Diagnostic and Immunization Studies
No full textRaising of alpacas as exotic livestock for wool and meat production and as companion animals is growing in importance in the United States, Europe and Australia. Furthermore the alpaca, as well as the rest of the camelids, possesses the peculiarity of producing single-chain antibodies from which nanobodies can be generated. Nanobodies, due to their structural simplicity and reduced size, are very versatile in terms of manipulation and bio-therapeutic exploitation. In fact the biotech companies involved in nanobody production and application continue to grow in number and size. Hence, the development of reagents and tools to assist in the further growth of this new scientific and entrepreneurial reality is becoming a necessity. These are needed mainly to address alpaca disease diagnosis and prophylaxis, and to develop alpaca immunization strategies for nanobody generation. For instance an immortalized alpaca cell line would be extremely valuable. In the present work the first stabilized alpaca cell line from alpaca skin stromal cells (ASSCs) was generated and characterized. This cell line was shown to be suitable for replication of viruses bovine herpesvirus-1, bovine viral diarrhea virus and caprine herpesvirus-1 and the endocellular parasite Neospora caninum. Moreover ASSCs were easy to transfect and transduce by several methods. These two latter characteristics are extremely useful when recombinant antigens need to be produced in a host homologous system. This work could be considered as a starting point for the expansion of the biotechnologies linked to alpaca farming and industry
MICRO-CT IN DRUG DISCOVERY: LONGITUDINAL DETECTION OF PARENCHYMAL CHANGES IN A MURINE MODEL OF LUNG FIBROSIS
No full textIn vivo imaging of transiently transgenized mice with a bovine interleukin 8 (CXCL8) promoter/luciferase reporter construct.
No full textOne of the most remarkable properties of interleukin 8 (CXCL8/IL-8), a chemokine with known additional functions also in angiogenesis and tissue remodeling, is the variation of its expression levels. In healthy tissues, IL-8 is barely detectable, but it is rapidly induced by several folds in response to proinflammatory cytokines, bacterial or viral products, and cellular stress. Although mouse cells do not bear a clear homologous IL-8 gene, the murine transcriptional apparatus may well be capable of activating or repressing a heterologous IL-8 gene promoter driving a reporter gene. In order to induce a transient transgenic expression, mice were systemically injected with a bovine IL-8 promoter-luciferase construct. Subsequently mice were monitored for luciferase expression in the lung by in vivo bioluminescent image analysis over an extended period of time (up to 60 days). We demonstrate that the bovine IL-8 promoter-luciferase construct is transiently and robustly activated 3-5 hours after LPS and TNF-α instillation into the lung, peaking at 35 days after construct delivery. Bovine IL-8 promoter-luciferase activation correlates with white blood cell and neutrophil infiltration into the lung. This study demonstrates that a small experimental rodent model can be utilized for non-invasively monitoring, through a reporter gene system, the activation of an IL-8 promoter region derived from a larger size animal (bovine). This proof of principle study has the potential to be utilized also for studying primate IL-8 promoter regions
DEVELOPMENT OF A CF, IL-8 TRANSGENIC MOUSE MODEL FOR THE IN VIVO LONG-TERM MONITORING OF LUNG INFLAMMATION
No full textno available; Meeting Abstract: 18
The Aresys FF-SAR Service for Cryosat-2 at ESA GPOD
No full textThe Fully-Focused SAR (FF-SAR) processing, introduced in Egido and Smith (2016) allows obtaining a maximum resolution of 0.5 m in the along-track direction. It provides significant benefits for inland water altimetry investigations allowing the successful investigation of very small rivers and canals (Kleinherenbrink, 2020) that are typically harder to be analysed by using unfocused Delay-Doppler SAR (DD-SAR) data (about 300 m resolution in the along-track direction).In its development, two major limitations were associated with the FF-SAR processing: 1) the presence of evenly spaced high sidelobes in the Point Target Response (PTR) due to the closed-loop burst mode implemented in Sentinel-3 & Cryosat-2 altimeter payloads, used for initial FF-SAR investigations, and 2) the heavy computational burden with respect to the unfocused DD-SAR processing. The first limitation can be overcome by designing the radar system differently adopting an open-loop transmission scheme as, for instance, the one implemented in the altimeter payload of the Sentinel-6 Michael Freilich mission, launched on 21 November 2020. The second limitation has been addressed in research works following Egido and Smith (2016) indicating that an improvement in terms of computational burden can be achieved by adopting algorithms in the frequency domain (Guccione et al., 2018).Being the role of FF-SAR for future inland water altimetry well understood, along with the possibility to see it implemented with reduced drawbacks during the Sentinel-6 Michael Freilich mission, a collaboration has started between the ESA GPOD Team, already hosting the successful SARvatore services portfolio for unfocused SAR & SARin altimetry, and Aresys. Aresys has developed a generic FF-SAR prototype processor, that is able to process data acquisition from different instruments and exploiting the frequency-domain Omega-K algorithm (Guccione et al., 2018 & Scagliola et al., 2018). The Aresys's FFSAR prototype processor for CryoSat-2 allows users to process, on line and on demand, low-level CryoSat FBR products in SAR mode up to FF-SAR Level-1 products with self-customized options. Additionally a wide set of processing parameters is configurable, allowing as an example to select the along-track resolution or to obtain FFSAR multilooked waveforms at the desired posting rate. The collaboration led to the creation of a new service for the processing of CryoSat Baseline D data in FF-SAR mode. Users will be able to select the following options: 1) range oversampling factor, 2) bandwidth factor (responsible for the along-track resolution value) and 3) multilook posting rate (1Hz-500Hz). Geophysical corrections and L2 estimates from both a threshold peak retracker and an ALES-like subwaveform retracker are part of the output package. In preliminary open ocean analyses, very good results on SSH noise have been obtained by the ALES-like subwaveform retracker.In this presentation, the Aresys FF-SAR prototype processor is described and the outcome of some preliminary validation activities, performed by a group of altimetry researchers, is reported. The service is scheduled to open to all GPOD/SARvatore users in the first semester of 2021. Future evolutions should include the extension of the service to Sentinel-3 and Sentinel-6 data.Astrodynamics & Space Mission
The Devil's altar? : crime and the early modern public house
No full textWas the early modern public house really such a dangerous place, as Puritan preachers (and many historians) suggested? This article discusses offences by publicans and patrons. It argues that the evidence for crime needs to be carefully contextualised and that taverns could stabilise as well as threaten the social order
Flexible time–space network formulation and hybrid metaheuristic for conflict-free and energy-efficient path planning of automated guided vehicles
No full textOperations of Automated Guided Vehicles (AGVs) are desired to be more energy-efficient while maintaining high transport productivity, motivated by the green production requirements. This paper investigates a new energy-efficient planning problem for determining conflict-free paths of the AGVs in its transport roadmap. In this problem, the vehicle path and transport time in the roadmap are jointly optimized, based on a flexible time–space network (FTSN). We provide the mathematical problem formulation of the energy-efficient path planning problem. The resulting optimization problem is proved to be a non-convex mixed-integer nonlinear programming which is computationally intractable. We further propose a hybrid metaheuristic that integrates the genetic algorithm and estimation of the distribution algorithm to improve its computational efficiency. Numerical results show the effectiveness of the developed algorithm based on the FTSN framework, compared to the existing metaheuristics, the conventional path planning method, and a commercial solver. The proposed method has a wide application in improving energy use of material handling, providing a guiding significance on promoting cleaner production of flexible manufacturing systems.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
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