17 research outputs found

    Advancing cell therapies for intervertebral disc regeneration from the lab to the clinic: recommendations of the ORS spine section

    Get PDF
    Intervertebral disc degeneration is strongly associated with chronic low back pain, a leading cause of disability worldwide. Current back pain treatment approaches (both surgical and conservative) are limited to addressing symptoms, not necessarily the root cause. Not surprisingly therefore, long‐term efficacy of most approaches is poor. Cell‐based disc regeneration strategies have shown promise in preclinical studies, and represent a relatively low‐risk, low‐cost, and durable therapeutic approach suitable for a potentially large patient population, thus making them attractive from both clinical and commercial standpoints. Despite such promise, no such therapies have been broadly adopted clinically. In this perspective we highlight primary obstacles and provide recommendations to help accelerate successful clinical translation of cell‐based disc regeneration therapies. The key areas addressed include: (a) Optimizing cell sources and delivery techniques; (b) Minimizing potential risks to patients; (c) Selecting physiologically and clinically relevant efficacy metrics; (d) Maximizing commercial potential; and (e) Recognizing the importance of multidisciplinary collaborations and engaging with clinicians from inception through to clinical trials

    Eisenbahnbrücken auf der Erzbahnlinie in Nordschweden - Erhöhung der Achslasten von 14 auf 32.5 metrische Tonnen : [Railway bridges on the Iron Ore line in Northern Sweden  - From axle loads of 14 to 32.5 metric tons]

    No full text
    Die Erzbahnlinie wurde um 1900 gebaut und überquert in ihrem Verlauf über 100 Brücken. Sie ist mehr als 500 km lang und verläuft von den Minen in Nordschweden zu den Häfen am Atlantik und an der Ostsee. Die ursprüngliche Achslast betrug 14 Tonnen. Zur Senkung der Transportkosten wurde die Achslast kontinuierlich erhöht, 1955 auf 25 Tonnen, 1998 auf 30 Tonnen und schliesslich auf 32,5 Tonnen im Jahr 2017 bzw. 2019. Der Erhöhung der Achslast ging jeweils ein Monitoring und eine Begutachtung der Brücken voraus. Dabei zeigte sich, dass viele dieser Brücken eine höhere Last tragen können, als ursprünglich beim Entwurf vorgesehen. Es werden Erfahrungen aus Studien vorgestellt, die zeigen ,dass durch gut geplante Erhaltungs- und Instalthaltungsprogramme/Ersatzneubauten viel Geld gespart werden kann. The Iron Ore Railway Line was built around 1900 and has more than 100 bridges. It has a length of ca 500 km and runs from the mines in northern Sweden to harbours on the Atlantic and on the Baltic. The original axle load was 14 ton. In order to lower freight costs, the axle loads has gradually been increased to 25 ton in 1955, to 30 ton in 1998,  and to 32.5 ton in 2017-2019. The increases in axle loads have been proceeded by monitoring and assessment studies of the bridges. Many of the bridges could carry a higher load than what it was designed for. Experiences from studies are presented showing that much money can be saved by a well planned maintenance and retrofitting/replacement program

    Railway Bridges on the Iron Ore Line in Northern Sweden : From Axle Loads of 14 to 32,5 ton

    No full text
    The Iron Ore Railway Line was built around 1900 and has more than 100 bridges. It has a length of ca 500 km and runs from Kiruna and Malmberget in northern Sweden to the ice-free harbour in Narvik in Norway on the Atlantic and to Luleå in Sweden on the Baltic. The original axle load was 14 ton. The axle load has gradually been increased to 25 ton in 1955, to 30 ton in 1998 and to 32,5 ton in 2017. The increases in axle loads have been preceded by monitoring and assessment studies of the bridges. The capacity and need for strengthening or replacement of the bridges have been evaluated. Many of the bridges could carry a higher load than what it was designed for. Experiences from studies before the axle load was increased in 1998 and 2017 are presented and discussed.ISBN för värdpublikation: 978-1-5108-9208-8</p

    A Parametric Study of an old Concrete Trough Bridge using non-linear Finite Element analysis

    No full text
    At least 20% of existing railway bridges in Sweden are reinforced concrete (RC) trough bridge that consist in a slab carried by two longitudinal main beams. As these bridges are getting old, there is an urging need to assess their remaining capacity with the aim of prolonging their service lives. The limited literature on the topic has pointed out that there is a significant difference between the capacity predicted by available codes and that obtained experimentally. In this paper, a review of the Bridge and Tunnel Management database (BaTMan) of railway infrastructure in Sweden, is carried out to gain an overview of the current state of the Swedish railway bridge, with focus on trough bridges. Then, a non-linear finite element model is calibrated using the experimental results of the previous testing of a decommissioned trough bridge. The model is used in a parametric study where the effect of key mechanical parameters on the capacity of trough bridges is studied. ISBN for host publication: 978-385748183-3</p

    Pressure Distribution Patterns Between the Ballast and the Concrete Slab in Railway Trough Bridges

    No full text
    In Sweden, a substantial amount of railway bridges is approaching their intended lifespans and are planned to be replaced. However, it is not sustainable neither from a financial nor an environmental perspective to replace these bridges if they are still sound and safe. Thus, an evaluation of their actual capacity is required with the aim of extending their lifespans. A way to obtain a more accurate capacity is to determine the loads that are acting on them. Available literature points out the lack of experimental investigations on sleeper-ballast contact pressure, as well as on the stress distribution along and across the ballast. Consequently, railway bridge design has been based on traditional rather than rational assumptions, which can be quite conservative. In this paper, a review of models is carried out for evaluating stress patterns on the surface of the slab on ballasted concrete bridges. Then, a simplified finite element model of a concrete trough bridge, a common type of structure in Sweden, is used in a parametric analysis aimed to understand how the identified pressure distribution patterns affect the performance of this type of structure. Finally, with the purpose of studying how some parameters influence the bridge safety, a probabilistic reliability analysis is used. The reliability index beta (b) is obtained using the polynomial response surface method and its value is compared for different boundary condition scenarios. Also, the sensitivity factors for the considered random variables are compared and analyzed. Results show that the assumption of support condition and pressure pattern has a significant impact on the capacity, failure mode and probability of failure of this type of structure.ISBN för värdpublikation: 978-981-18-2016-8</p

    Full Scale Test of a PC Bridge to Calibrate Assessment Methods

    No full text
    In this paper, experiences on the development of an assessment method for existing bridges are presented. The method is calibrated using the results of full-scale testing to failure of a prestressed bridge in Sweden. To evaluate the key parameters for the structural response, measured by deflections, strains in tendons and stirrups and crack openings, a sensitivity study based on the concept of fractional factorial design is incorporated to the assessment. Results showed that the most significant parameters are related to the tensile properties of the concrete (tensile strength and fracture energy) and the boundary conditions. A finite element (FE) model in which the results of the sensitivity analysis were applied, was able to predict accurately the load-carrying capacity of the bridge and its failure mode. Two additional existing prestressed concrete bridges, that will be used to improve further the method, are also described, and discussed.Funder: BBT; LKAB; Swedish Universities of the Built Environment</p
    corecore