550 research outputs found

    DEVELOPMENT OF SPATIOTEMPORAL CONGESTION PATTERN OBSERVATION MODEL USING HISTORICAL AND NEAR REAL TIME DATA

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    Traffic congestion is not foreign to major metropolitan areas. Congestion in large cities often is associated with dense land developments and continued economic growth. In general, congestion can be classified into two categories: recurring and nonrecurring. Recurring congestion often occurs at certain parts of highway networks, referred to as bottleneck locations. Nonrecurring congestion, on the other hand, can be caused by different reasons, including work zones, special events, accidents, inclement weather, poor signal timing, etc. The work presented here demonstrates an approach to effectively identifying spatiotemporal patterns of traffic congestion at a network level. The Metro Atlanta highway network was used as a case study. Real time traffic data was acquired from the Georgia Department of Transportation (GDOT) Navigator system. For a qualitative analysis, speed data was categorized into three levels: low, median, and high. Cluster analysis was performed with respect to the categorized speed data in the spatiotemporal domain to identify where and when congestion has occurred and for how long, which indicate the severity of congestion. This qualitative analysis was performed by day of week to identify potential variation in congestion over weekdays and weekend. For a quantitative analysis, actual speed data was used to construct daily spatiotemporal maps to reveal congestion patterns at a more granular level, where congestion is represented as “cloud” in the spatiotemporal domain. Future work will be focusing on deep learning of congestion patterns using Convolutional Long Short Term Memory (ConvLSTM) networks

    An astrometric mass estimate for asteroid (223) Rosa

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    Outer main belt asteroid (223) Rosa is a possible flyby target of opportunity for ESA's (European Space Agency) JUpiter ICy moons Explorer (JUICE) mission when passing the asteroid belt on the way to Jupiter. The very low albedo and the featureless red spectra indicate a P-type asteroid in the Tholen taxonomy, though the yet known bulk density did not match very well this classification. Aim of this work was to derive new estimates for the mass and for the bulk density for (223) Rosa. The mass of Rosa was derived by analyzing the gravitational deflection of small `test' asteroids which had a close encounter with Rosa in the past. To find such events suitable for the mass determination, an encounter search with about 900,000 asteroids over the time span 198020301980-2030 was performed. Three encounters were identified from which two independent mass estimates for Rosa were derived: M=(5.32±2.17)×1017M = (5.32 \pm 2.17) \times 10^{17} kg and M=(3.15±1.14)×1017M = (3.15 \pm 1.14) \times 10^{17} kg, respectively. The weighted mean is M=(3.62±1.25)×1017M = (3.62 \pm 1.25) \times 10^{17} kg. This yields to a bulk density of ρ=1.2±0.5gcm3\rho = 1.2 \pm 0.5 \mathrm{\,g\,cm^{-3}}, when adopting an effective diameter of D=83±8D = 83 \pm 8 km. This bulk density estimate is consistent with typical densities for Tholen taxonomy P-type asteroids.Comment: 6 pages, 4 figures, accepted for publication in A&

    Biomaterial-based strategies for craniofacial tissue engineering

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    Damage to or loss of craniofacial tissues, often resulting from neoplasm, trauma, or congenital defects, can have devastating physical and psychosocial effects. The presence of many specialized tissue types integrated within a relatively small volume leads to difficulty in achieving complete functional and aesthetic repair. Tissue engineering offers a promising alternative to conventional therapies by potentially enabling the regeneration of normal native tissues. Initially, a stimulus responsive biomaterial designed for injectable cell delivery applications was investigated with the goal of providing a substrate for osteogenic differentiation of delivered cells. In order to enable faster clinical translation, later efforts focused on novel combinations of regulated materials. Most common approaches using cell delivery for bone tissue engineering involve the harvest and ex vivo expansion of progenitor cell populations over multiple weeks and cell passages. The effect of aging and passage on proliferation and differentiation were analyzed using murine mesenchymal stem cells as a model. These cells lose their ability to proliferate and differentiate with increases in donor age and passages during cell culture. Delivery of uncultured bone marrow mononuclear cells was then investigated, and it was determined that when delivered to porous scaffolds these cells, which can be harvested, isolated, and returned to the body within the setting of a single operation, significantly increased bone regeneration in vivo. Finally, because these techniques of scaffold implantation and cell delivery would likely fail if delivered to an exposed or infected wound, a method of space maintenance was investigated. Space maintainers made of poly(methyl methacrylate) and having tunable porosity and pore interconnectivity were evaluated within a clean/contaminated mandibular defect. Low porosity space maintainers were found to prevent soft tissue collapse or contracture into the bony defect and allowed surrounding soft tissues to penetrate the pores of the implant, enabling healing over 12 weeks. The tissue response and wound healing characteristics of these implant was favorable when compared to solid or high porosity implants. Although optimization and further investigation of these techniques is necessary, in combination these approaches demonstrate one possible and translatable approach towards craniofacial tissue regeneration

    Effects of Tier 1 enhancement training on teachers' percentage of correctly implemented instructional units

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    Early intervention models such as Response to Intervention have shown promise in reducing risk of academic failure (Bursuck et al., 2005; Foorman, Fletcher, Francis, & Schatschneider, 1998). General education teachers assume primary responsibility for instruction in RTI; however, many report lack of preparation for this role due to lack of high quality, sustained professional development (Schumaker et al., 2002). Professional development models that include a combination of inservice and coaching have demonstrated effectiveness in promoting sustained changes in teachers’ instruction (Yoon et al., 2008). This study examined the effects of inservice plus coaching on 1st grade teachers’ accurate delivery of instructional units in CM. The extent to which changes in instruction generalized to an untrained math session was also examined. Teachers were trained to use a combination of whole-class instruction strategies, including model-lead-test for introducing new concepts and correcting errors, choral responding, and response cards. Results indicated that all teachers improved their delivery of instruction after the inservice, with a second level of growth achieved after coaching. Results indicated some generalization to an untrained math session as well. Teachers also reported high levels of satisfaction using the strategies, as well as high levels of acceptability with the training model

    Donor age and cell passage affects differentiation potential of murine bone marrow-derived stem cells

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    <p>Abstract</p> <p>Background</p> <p>Bone marrow-derived mesenchymal stem cells (BMSCs) are a widely researched adult stem cell population capable of differentiation into various lineages. Because many promising applications of tissue engineering require cell expansion following harvest and involve the treatment of diseases and conditions found in an aging population, the effect of donor age and <it>ex vivo </it>handling must be understood in order to develop clinical techniques and therapeutics based on these cells. Furthermore, there currently exists little understanding as to how these two factors may be influenced by one another.</p> <p>Results</p> <p>Differences in the adipogenic, chondrogenic, and osteogenic differentiation capacity of murine MSCs harvested from donor animals of different age and number of passages of these cells were observed. Cells from younger donors adhered to tissue culture polystyrene better and proliferated in greater number than those from older animals. Chondrogenic and osteogenic potential decreased with age for each group, and adipogenic differentiation decreased only in cells from the oldest donors. Significant decreases in differentiation potentials due to passage were observed as well for osteogenesis of BMSCs from the youngest donors and chondrogenesis of the cells from the oldest donors.</p> <p>Conclusion</p> <p>Both increasing age and the number of passages have lineage dependent effects on BMSC differentiation potential. Furthermore, there is an obvious interplay between donor age and cell passage that in the future must be accounted for when developing cell-based therapies for clinical use.</p

    Synthesis and Characterization of Thermally and Chemically Gelling Injectable Hydrogels for Tissue Engineering

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    Novel, injectable hydrogels were developed that solidify through a dual-gelation, physical and chemical, mechanism upon preparation and elevation of temperature to 37°C. A thermogelling, poly(N-isopropylacrylamide)-based macromer with pendant epoxy rings and a hydrolyticallydegradable polyamidoamine-based diamine crosslinker were synthesized, characterized, and combined to produce in situ forming hydrogel constructs. Network formation through the epoxyamine reaction was shown to be rapid and facile, and the progressive incorporation of the hydrophilic polyamidoamine crosslinker into the hydrogel was shown to mitigate the often problematic tendency of thermogelling materials to undergo significant post-formation gel syneresis. The results suggest that this novel class of injectable hydrogels may be attractive substrates for tissue engineering applications due to the synthetic versatility of the component materials and beneficial hydrogel gelation kinetics and stability

    Mechanisms of murine cerebral malaria: Multimodal imaging of altered cerebral metabolism and protein oxidation at hemorrhage sites.

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    Using a multimodal biospectroscopic approach, we settle several long-standing controversies over the molecular mechanisms that lead to brain damage in cerebral malaria, which is a major health concern in developing countries because of high levels of mortality and permanent brain damage. Our results provide the first conclusive evidence that important components of the pathology of cerebral malaria include peroxidative stress and protein oxidation within cerebellar gray matter, which are colocalized with elevated nonheme iron at the site of microhemorrhage. Such information could not be obtained previously from routine imaging methods, such as electron microscopy, fluorescence, and optical microscopy in combination with immunocytochemistry, or from bulk assays, where the level of spatial information is restricted to the minimum size of tissue that can be dissected. We describe the novel combination of chemical probe-free, multimodal imaging to quantify molecular markers of disturbed energy metabolism and peroxidative stress, which were used to provide new insights into understanding the pathogenesis of cerebral malaria. In addition to these mechanistic insights, the approach described acts as a template for the future use of multimodal biospectroscopy for understanding the molecular processes involved in a range of clinically important acute and chronic (neurodegenerative) brain diseases to improve treatment strategies

    Constraints on the structure and seasonal variations of Triton’s atmosphere from the 5 October 2017 stellar occultation and previous observations

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    J.M.O. acknowledges financial support from the Portuguese Foundation for Science and Technology (FCT) and the European Social Fund (ESF) through the PhD grant SFRH/BD/131700/2017. The work leading to these results has received funding from the European Research Council under the European Community's H2020 2014-2021 ERC grant Agreement nffi 669416 "Lucky Star". We thank S. Para who supported some travels to observe the 5 October 2017 occultation. T.B. was supported for this research by an appointment to the National Aeronautics and Space Administration (NASA) Post-Doctoral Program at the Ames Research Center administered by Universities Space Research Association (USRA) through a contract with NASA. We acknowledge useful exchanges with Mark Gurwell on the ALMA CO observations. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. J.L.O., P.S.-S., N.M. and R.D. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709), they also acknowledge the financial support by the Spanish grant AYA-2017-84637-R and the Proyecto de Excelencia de la Junta de Andalucia J.A. 2012-FQM1776. The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement no. 687378, as part of the project "Small Bodies Near and Far" (SBNAF). P.S.-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 "LEO-SBNAF". The work was partially based on observations made at the Laboratorio Nacional de Astrofisica (LNA), Itajuba-MG, Brazil. The following authors acknowledge the respective CNPq grants: F.B.-R. 309578/2017-5; R.V.-M. 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3 and 305917/2019-6; M.A. 427700/20183, 310683/2017-3, 473002/2013-2. This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brasil (CAPES) -Finance Code 001 and the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant 465376/2014-2). G.B.R. acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 and CAPES-PRINT/UNESP grant 88887.571156/2020-00, M.A. FAPERJ grant E26/111.488/2013 and A.R.G.Jr. FAPESP grant 2018/11239-8. B.E.M. thanks CNPq 150612/2020-6 and CAPES/Cofecub-394/2016-05 grants. Part of the photometric data used in this study were collected in the frame of the photometric observations with the robotic and remotely controlled telescope at the University of Athens Observatory (UOAO; Gazeas 2016). The 2.3 m Aristarchos telescope is operated on Helmos Observatory by the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens. Observations with the 2.3 m Aristarchos telescope were carried out under OPTICON programme. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 730890. This material reflects only the authors views and the Commission is not liable for any use that may be made of the information contained therein. The 1. 2m Kryoneri telescope is operated by the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens. The Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) is managed by the Fondazione Clement Fillietroz-ONLUS, which is supported by the Regional Government of the Aosta Valley, the Town Municipality of Nus and the "Unite des Communes valdotaines Mont-Emilius". The 0.81 m Main Telescope at the OAVdA was upgraded thanks to a Shoemaker NEO Grant 2013 from The Planetary Society. D.C. and J.M.C. acknowledge funds from a 2017 'Research and Education' grant from Fondazione CRT-Cassa di Risparmio di Torino. P.M. acknowledges support from the Portuguese Fundacao para a Ciencia e a Tecnologia ref. PTDC/FISAST/29942/2017 through national funds and by FEDER through COMPETE 2020 (ref. POCI010145 FEDER007672). F.J. acknowledges Jean Luc Plouvier for his help. S.J.F. and C.A. would like to thank the UCL student support observers: Helen Dai, Elise Darragh-Ford, Ross Dobson, Max Hipperson, Edward Kerr-Dineen, Isaac Langley, Emese Meder, Roman Gerasimov, Javier Sanjuan, and Manasvee Saraf. We are grateful to the CAHA, OSN and La Hita Observatory staffs. This research is partially based on observations collected at Centro Astronomico HispanoAleman (CAHA) at Calar Alto, operated jointly by Junta de Andalucia and Consejo Superior de Investigaciones Cientificas (IAA-CSIC). This research was also partially based on observation carried out at the Observatorio de Sierra Nevada (OSN) operated by Instituto de Astrofisica de Andalucia (CSIC). This article is also based on observations made with the Liverpool Telescope operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. Partially based on observations made with the Tx40 and Excalibur telescopes at the Observatorio Astrofisico de Javalambre in Teruel, a Spanish Infraestructura Cientifico-Tecnica Singular (ICTS) owned, managed and operated by the Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA). Tx40 and Excalibur are funded with the Fondos de Inversiones de Teruel (FITE). A.R.R. would like to thank Gustavo Roman for the mechanical adaptation of the camera to the telescope to allow for the observation to be recorded. R.H., J.F.R., S.P.H. and A.S.L. have been supported by the Spanish projects AYA2015-65041P and PID2019-109467GB-100 (MINECO/FEDER, UE) and Grupos Gobierno Vasco IT1366-19. Our great thanks to Omar Hila and their collaborators in Atlas Golf Marrakech Observatory for providing access to the T60cm telescope. TRAPPIST is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant PDR T.0120.21. TRAPPIST-North is a project funded by the University of Liege, and performed in collaboration with Cadi Ayyad University of Marrakesh. E.J. is a FNRS Senior Research Associate.Context. A stellar occultation by Neptune's main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection. Aims. We aimed at constraining Triton's atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis. Methods. We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range similar to 8 km to similar to 190 km, corresponding to pressure levels from 9 mu bar down to a few nanobars. Results. (i) A pressure of 1.18 +/- 0.03 mu bar is found at a reference radius of 1400 km (47 km altitude). (ii) A new analysis of the Voyager 2 radio science occultation shows that this is consistent with an extrapolation of pressure down to the surface pressure obtained in 1989. (iii) A survey of occultations obtained between 1989 and 2017 suggests that an enhancement in surface pressure as reported during the 1990s might be real, but debatable, due to very few high S/N light curves and data accessible for reanalysis. The volatile transport model analysed supports a moderate increase in surface pressure, with a maximum value around 2005-2015 no higher than 23 mu bar. The pressures observed in 1995-1997 and 2017 appear mutually inconsistent with the volatile transport model presented here. (iv) The central flash structure does not show evidence of an atmospheric distortion. We find an upper limit of 0.0011 for the apparent oblateness of the atmosphere near the 8 km altitude.Portuguese Foundation for Science and Technology SFRH/BD/131700/2017European Social Fund (ESF) SFRH/BD/131700/2017European Research Council under the European Community's H2020 2014-2021 ERC grant 669416Spanish Government SEV-2017-0709 AYA-2017-84637-R AYA-RTI2018-098657-J-I00Junta de Andalucia 2012-FQM1776European Union's Horizon 2020 Research and Innovation Programme, as part of the project "Small Bodies Near and Far" (SBNAF) 687378Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF) 309578/2017-5 304544/2017-5 401903/2016-8 308150/2016-3 305917/2019-6 427700/2018-3 310683/2017-3 473002/2013-2Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) 001Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 465376/2014-2 CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 CAPES-PRINT/UNESP grant 88887.571156/2020-00Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ) E26/111.488/2013Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2018/11239-8Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 150612/2020-6European Union's Horizon 2020 research and innovation programme 730890Regional Government of the Aosta ValleyTown Municipality of NusUnite des Communes valdotaines Mont-EmiliusPlanetary SocietyFondazione CRT-Cassa di Risparmio di TorinoPortuguese Foundation for Science and Technology PTDC/FISAST/29942/2017FEDER through COMPETE 2020 POCI010145 FEDER007672UK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC)Fondos de Inversiones de Teruel (FITE)Spanish Government AYA2015-65041P PID2019-109467GB-100Grupos Gobierno Vasco IT1366-19Fonds de la Recherche Scientifique - FNRS PDR T.0120.21University of LiegeCAPES/Cofecub-394/2016-0

    Development of nanofiber-reinforced hydrogel scaffolds for nucleus pulposus regeneration by a combination of electrospinning and spraying technique

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    In this work a new method is presented to efficiently produce hydrogel scaffolds reinforced with nanofibers to show enhanced mechanical properties and improved structural integrity. The method is based on a combination of air brush spraying of a hydrogel and electrospinning of nanofibers. With air brush spraying the controllability is enhanced and the potential for scale-up increased. The developed method was used to successfully reinforce gellan gum hydrogels with electrospun polycaprolactone nanofibers. Optical and rheological evaluations were performed and showed that parameters such as the amount of incorporated nanofibers, gellan gum concentration and calcium chloride (crosslinker) concentrations could be used to modulate material properties. Incorporation of a small amount of nanofibers had a reinforcing effect and resulted in a hydrogel with rheological properties similar to the human nucleus pulposus (NP). The method is flexible and carries potential for designing scaffolds for e.g. NP tissue regeneration.The authors gratefully acknowledge funding from the Disc Regeneration Project (grant agreement number: NMP-LA-2008-213904) from the European Community. Also, they acknowledge RISE Research Institutes of Sweden Holding AB for financial support of this study

    PLGA-chitosan/PLGA-alginate Nanoparticle Blends as Biodegradable Colloidal Gels for Seeding Human Umbilical Cord Mesenchymal Stem Cells

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    The natural polymers chitosan and alginate represent an attractive material choice for biodegradable inplants. These were used as coating materials to make positively and negatively charged PLGA nanoparticles, respectively. After blending at total solids concentration >10% wt/vol, these oppositely charged nanoparticles yielded a cohesive colloidal gel. Electrostatic forces between oppositely charged nanoparticles produced a stable 3-D porous network that may be extruded or molded to the desired shape. This high concentration colloidal system demonstrated shear-thinning behavior due to the disruption of interparticle interactions. Once the external force was removed, the cohesive property of the colloidal gel was recovered. Scanning electron micrographs of dried colloidal networks revealed an organized, 3-D microporous structure. Rheological studies were employed to probe the differences in plasticity and shear sensitivity of colloidal gels. Viability tests of hUCMSCs seeded on the colloidal gels also demonstrated the negligible cytotoxicity of the materials. All the results indicated the potential application of the biodegradable colloidal gels as an injectable scaffold in tissue engineering and drug release
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