Daily 30-min exposure to artificial gravity during 60 days of bed rest does not maintain aerobic exercise capacity but mitigates some deteriorations of muscle function: results from the AGBRESA RCT

Purpose: Spaceflight impairs physical capacity. Here we assessed the protective effect of artificial gravity (AG) on aerobic exercise capacity and muscle function during bed rest, a spaceflight analogue. Methods: 24 participants (33 ± 9 years, 175 ± 9 cm, 74 ± 10 kg, 8 women) were randomly allocated to one of three groups: continuous AG (cAG), intermittent AG (iAG) or control (CTRL). All participants were subjected to 60 days of six-degree head-down tilt bed rest, and subjects of the intervention groups completed 30 min of centrifugation per day: cAG continuously and iAG for 6 × 5 min, with an acceleration of 1g at the center of mass. Physical capacity was assessed before and after bed rest via maximal voluntary contractions, cycling spiroergometry, and countermovement jumps. Results: AG had no significant effect on aerobic exercise capacity, flexor muscle function and isometric knee extension strength or rate of force development (RFD). However, AG mitigated the effects of bed rest on jumping power (group * time interaction of the rmANOVA p < 0.001; iAG − 25%, cAG − 26%, CTRL − 33%), plantar flexion strength (group * time p = 0.003; iAG − 35%, cAG − 31%, CTRL − 48%) and plantar flexion RFD (group * time p = 0.020; iAG − 28%, cAG − 12%, CTRL − 40%). Women showed more pronounced losses than men in jumping power (p < 0.001) and knee extension strength (p = 0.010). Conclusion: The AG protocols were not suitable to maintain aerobic exercise capacity, probably due to the very low cardiorespiratory demand of this intervention. However, they mitigated some losses in muscle function, potentially due to the low-intensity muscle contractions during centrifugation used to avoid presyncope

HTR-TN Achievements and Prospects for Future Developments

It is already 10 years since the (European) High Temperature Reactor Technology Network (HTR-TN) launched a program for development of HTR technology, which expanded through three successive Euratom framework programs, with many projects in line with the network strategy. Widely relying in the beginning on the legacy of the former European HTR developments (DRAGON, AVR, THTR, etc.) that it contributed to safeguard, this program led to advances in HTR/VHTR technologies and produced significant results, which can contribute to the international cooperation through Euratom involvement in the Generation IV International Forum (GIF). the main achievements of the European program, performed in complement to efforts made in several European countries and other GIF partners, are presented: they concern the validation of computer codes (reactor physics, as well as system transient analysis from normal operation to air ingress accident and fuel performance in normal and accident conditions), materials (metallic materials for vessel, direct cycle turbines and intermediate heat exchanger, graphite, etc.), component development, fuel manufacturing and irradiation behavior, and specific HTR waste management (fuel and graphite). Key experiments have been performed or are still ongoing, like irradiation of graphite and of fuel material (PYCASSO experiment), high burn-up fuel PIE, safety test and isotopic analysis, IHX mock-up thermohydraulic test in helium atmosphere, air ingress experiment for a block type core, etc. Now HTR-TN partners consider that it is time for Europe to go a step forward toward industrial demonstration. In line with the orientations of the "Strategic Energy Technology Plan (SET-Plan)" recently issued by the European Commission that promotes a strategy for development of low-carbon energy technologies and mentions Generation IV nuclear systems as part of key technologies, HTR-TN proposes to launch a program for extending the contribution of nuclear energy to industrial process heat applications addressing (1) the development of a flexible HTR that can be coupled to many different process heat and cogeneration applications with very versatile requirements, (2) the development of coupling technologies for such coupling, (3) the possible adaptations of process heat applications required for nuclear coupling, and (4) the integration and optimization of the whole coupled system. As a preliminary step for this ambitious program, HTR-TN endeavors to create a strategic partnership between nuclear industry and R&D and process heat user industries. [DOI: 10.1115/1.4000799

Optimising the early-stage rehabilitation process post-ACL reconstruction

Outcomes following anterior cruciate ligament reconstruction (ACLR) need improving, with poor return-to-sport rates and high risk of secondary re-injury. There is a need to improve rehabilitation strategies post-ACLR, if we can support enhanced patient outcomes. This paper discusses how to optimise the early-stage rehabilitation process post-ACLR. Early-stage rehabilitation is the vital foundation on which successful rehabilitation post-ACLR can occur. Without high quality early-stage (and pre-operative) rehabilitation, patients often do not overcome major aspects of dysfunction which limits knee function and ability to transition through subsequent stages of rehabilitation optimally. We highlight six main dimensions during the early-stage: (1) pain and swelling; (2) knee joint range of motion; (3) arthrogenic muscle inhibition and muscle strength; (4) movement quality/neuromuscular control during activities of daily living (5) psycho-social-cultural and environmental factors and (6) physical fitness preservation. The six do not share equal importance and the extent of time commitment devoted to each will depend on the individual patient. The paper provides recommendations on how to implement these into practice, discussing training planning and programming and suggests specific screening to monitor work and when the athlete can progress to the next stage (e.g., mid-stage rehabilitation entry criteria)

RAPHAEL: The European Union's (Very) High Temperature Reactor Technology Project

In April 2005, as part of its 6th Framework Programme, the European Union has started a new 4-year Integrated Project on Very High Temperature Reactors (RAPHAEL: Reactor for Process Heat and Electricity). The European Commission together with the more than 30 participating companies, R&D organizations and universities from different European countries finance the project together. The project was approved because of its ambitious technical objectives and its value for education and communication. Such a reactor was found to have a large potential in terms of safety (inherent safety features), environmental impact (robust fuel with no significant radioactive release), sustainability (high efficiency, potential suitability for various fuel cycles), and economics (simplifications arising from safety features). After the successful performance of related projects in the EU’s 5th Framework Programme which included amongst others the recovery of some of the past German experience and the re-establishment of important areas of R&D in Europe, RAPHAEL focuses now on remaining key technology needs for an industrial VHTR deployment, both specific to very high temperature and generic to all types of modular HTR with emphasis on combined process heat and electricity generation. Advanced technologies are explored in order to achieve the challenging performances required for a VHTR (900-1000°C, up to 200 GWd/tHM). RAPHAEL is structured in a similar way as the corresponding GIF VHTR projects: • Material selection and qualification for very high temperature components, graphite internals and vessel; • Component development, in particular the intermediate heat exchanger; • Fuel tests up to very high temperature and burn-up including modeling, safety tests to qualify the fuel in accidental conditions, fabrication of advanced fuel with potentially higher performance, and behavior of irradiated fuel in representative disposal conditions; • Code qualification for reactor physics and safety analysis through comparison with experimental data; • Adaptation of the safety approach to the VHTR specifics; • System integration to evaluate the feasibility and performance of the entire reactor; • Education and communication to foster understanding of the growing needs for nuclear power in general and for the technology of the VHTR in particular. RAPHAEL together with additional national contributions to this technology relies on strong links with related EU projects which are underway or proposed, e.g. on high temperature materials, waste management (graphite and fuel), hydrogen production, GFR technology and others. The well-established European High Temperature Reactor Technology Network HTR-TN serves as the platform for the coordination of the various projects. Significant parts of RAPHAEL may be shared with the signatories of the GIF VHTR projects.JRC.F.3-High Flux and Future Reactor