Introduction
Previous evidence has established that early surgery is beneficial to improve outcomes for individuals with native hip fractures in the elderly population. Patients who sustain a ...periprosthetic fracture have been demonstrated to have similar demographics and outcomes as those with native fractures around the hip and knee. We therefore set out to determine if there is a similar difference in perioperative outcomes between early and delayed surgery for periprosthetic fractures of the hip and knee through a systematic review and meta-analysis.
Methods
Literature search outputs were screened for studies meeting the inclusion criteria. The groups of early surgery and delayed surgery were defined by study authors. The primary outcome measure was 30 day mortality. Where there was sufficient study homogeneity, a random-effects meta-analysis was performed. Individual study risk of bias was assessed using the ROBINS-I criteria, with the GRADE criteria used for independent outcome evaluation. The review protocol was registered on PROSPERO prior to commencement (Registration number CRD42019149360).
Results
The inclusion criteria was met in 11 studies (
n
= 3006). Mean time to surgery from admission for reporting studies was 64 h. 59.6% patients underwent early surgery as defined by the study authors. We identified a significantly lower risk of 30 day mortality for those with early surgery versus delayed surgery (RR 0.21; 95% CI 0.05, 0.90;
p
= 0.04,
n
= 2022). There were also significantly better outcomes for early versus delayed surgery regarding: medical complications, length of stay, transfusion risk, and reoperation. The quality of evidence for all the individual outcomes was low or very low.
Conclusions
There is evidence that delaying surgery in those with periprosthetic fractures of the hip and knee has a deleterious impact on mortality and other important patient outcomes. There are, however, notable limitations to the existing available literature, with further appropriately designed large-scale studies required to confirm these findings.
The progenitor cells of the developing liver can differentiate toward both hepatocyte and biliary cell fates. In addition to the established roles of TGFβ and Notch signaling in this fate ...specification process, there is increasing evidence that liver progenitors are sensitive to mechanical cues. Here, we utilized microarrayed patterns to provide a controlled biochemical and biomechanical microenvironment for mouse liver progenitor cell differentiation. In these defined circular geometries, we observed biliary differentiation at the periphery and hepatocytic differentiation in the center. Parallel measurements obtained by traction force microscopy showed substantial stresses at the periphery, coincident with maximal biliary differentiation. We investigated the impact of downstream signaling, showing that peripheral biliary differentiation is dependent not only on Notch and TGFβ but also E-cadherin, myosin-mediated cell contractility, and ERK. We have therefore identified distinct combinations of microenvironmental cues which guide fate specification of mouse liver progenitors toward both hepatocyte and biliary fates.
We describe a new service model, the Orthopaedic Assessment Unit (OAU), designed to provide care for trauma patients during the COVID-19 pandemic. Patients without COVID-19 symptoms and isolated ...musculoskeletal injuries were redirected to the OAU.
We prospectively reviewed patients throughput during the peak of the global pandemic (7 May 2020 to 7 June 2020) and compared with our historic service provision (7 May 2019 to 7 June 2019). The Mann-Whitney and Fisher Exact tests were used to test the statistical significance of data.
A total of 1,147 patients were seen, with peak attendances between 11am and 2pm; 96% of all referrals were seen within 4h. The majority of patients were seen by orthopaedic registrars (52%) and nurse practitioners (44%). The majority of patients suffered from sprains and strains (39%), followed by fractures (22%) and wounds (20%); 73% of patients were discharged on the same day, 15% given follow up, 8% underwent surgery and 3% were admitted but did not undergo surgery. Our volume of trauma admissions and theatre cases decreased by 22% and 17%, respectively (
=0.058; 0.139). There was a significant reduction of virtual fracture clinic referrals after reconfiguration of services (
<0.001).
Rapid implementation of a specialist OAU during a pandemic can provide early definitive trauma care while exceeding national waiting time standards. The fall in trauma attendances was lower than anticipated. The retention of orthopaedic staff in the department to staff the unit and maintain a high standard of care is imperative.
In a new era of lunar exploration, pyroclastic deposits have been identified as valuable targets for resource utilization and scientific inquiry. Little is understood about the geomechanical ...properties and the trafficability of the surface material in these areas, which is essential for successful mission planning and execution. Past incidents with rovers highlight the importance of reliable information about surface properties for future, particularly robotic, lunar mission concepts. Characteristics of 149 boulder tracks are measured in Lunar Reconnaissance Orbiter Narrow Angle Camera images and used to derive the bearing capacity of pyroclastic deposits and, for comparison, mare and highland regions from the surface down to ~5‐m depth, as a measure of trafficability. Results are compared and complemented with bearing capacity values calculated from physical property data collected in situ during Apollo, Surveyor, and Lunokhod missions. Qualitative observations of tracks show no region‐dependent differences, further suggesting similar geomechanical properties in the regions. Generally, bearing capacity increases with depth and decreases with higher slope gradients, independent of the type of region. At depths of 0.19 to 5 m, pyroclastic materials have bearing capacities equal or higher than those of mare and highland material and, thus, may be equally trafficable at surface level. Calculated bearing capacities based on orbital observations are consistent with values derived using in situ data. Bearing capacity values are used to estimate wheel sinkage of rover concepts in pyroclastic deposits. This study's findings can be used in the context of traverse planning, rover design, and in situ extraction of lunar resources.
Plain Language Summary
Future explorers will be visiting pyroclastic deposits for research and resource extraction. However, the properties of the surface are not well known and it is unclear how well vehicles and humans are able to travel across these areas. Properties of 149 boulder tracks are measured in spacecraft imagery and are used to derive estimations for the strength of pyroclastic, mare, and highland area material from the surface down to ~5‐m depth. Results are compared and complemented with soil strength estimates that have been derived based on in situ measurements taken during previous lunar surface missions. In all regions of interest, tracks have similar appearances, implying that the surface material has comparable properties. Generally, soil strength increases with increasing depth and decreases with higher local slope angles. At depth, pyroclastic deposits show equal or significantly higher strength in comparison to mare and highland areas and, therefore, might be equally trafficable at surface level. Calculations based on globally distributed spacecraft images agree with values derived from Apollo‐era in situ data. Based on the soil strength, the sinkage of rovers in the areas of interest is estimated. Potential applications of this work include rover design and mission planning, infrastructure construction, and resource extraction.
Key Points
Bearing capacity of pyroclastic, mare, and highland regions is calculated based on measurements of boulder tracks in orbital images
Results agree with calculations based on in situ data—pyroclastic areas show no evidence of lower trafficability than maria and highlands
Sinkage of proposed mobility systems is estimated, which can be applied to rover requirements, traverse planning, and civil engineering
Abstract
The Schrödinger basin on the south polar lunar far side has been highlighted as a promising target for future exploration. This report provides a high-resolution geologic map in the ...southwest peak-ring (SWPR) area of the Schrödinger basin, emphasizing structural features and detailed mapping of exposed outcrops within the peak ring. Outcrops are correlated with mineralogical data from the Moon Mineralogical Mapper instrument. Geologic mapping reveals a complex structural history within the basin through a system of radially oriented faults. Further, the geologic map shows both faulted and magmatic contacts between peak-ring mineralogies, providing both structural and magmatic context for understanding lunar crustal evolution and polar region processes. To investigate these relationships and address key scientific concepts and goals from the National Research Council (NRC) report, we propose three traverse paths for a robotic sample return mission in the SWPR area. These traverses focus on addressing the highest priority science concepts and goals by investigating known outcrops with diverse mineralogical associations and visible contacts among them. Coinciding with the preparation for the 2024 Artemis III mission, NASA is increasing the priority of robotic exploration at the lunar south pole before the next crewed mission to the Moon. Through mapping the Schrödinger SWPR, we identified the extent of different lunar crustal mineralogies, inferred their geologic relationships and distribution, and pinpointed traversable routes to sample spectrally diverse outcrops and outcrop-derived boulders. The SWPR region is therefore a promising potential target for future exploration, capable of addressing multiple high-priority lunar science goals.
Water is one of the most vital resources required for future space exploration. By obtaining water from lunar regolith, humans are one step closer to being independent of Earth's resources enabling ...longer term exploration missions. Hydrogen reduction of ilmenite(FeTiO3) is often proposed as a technique for producing water on the Moon. ProSPA, a miniature analytical laboratory, will perform reduction of lunar soils as an In-Situ Resource Utilization (ISRU) demonstration on the lunar surface. The technique used by ProSPA will be useful for prospecting payloads with limited mass and power resources. This work considers the development and optimization of an ilmenite reduction procedure for use with the ProSPA instrument. It is shown that the reaction can be performed in a static (non-flowing) system, by utilizing a cold finger to collect the water produced from the reaction. Among the investigated parameters an initial H2:FeTiO3 ratio of 1, in this case equating to a hydrogen pressure of 418 mbar, proved to be best for providing maximum yields over 4 h when operating at 1000 °C. Results indicate that a maximum yield of 3.40 ± 0.17 wt % O2 can be obtained at 1000 °C (with a maximum possible yield of 10.5 wt % O2). When operating at higher temperatures of 1100 °C the ilmenite grains undergo a subsolidus reaction resulting in the formation of ferropseudobrookite and higher yields of 4.42 ± 0.18 wt % O2 can be obtained.
•Demonstration of reduction of ilmenite by H2 in a non-flowing system.•Proof of principle for an ISRU demonstration on the Moon.•Yields of up to 4.4 wt% O2 which is reasonable considering the constraints.
In situ resource utilisation (ISRU) refers to the extraction and use of local materials, and numerous ISRU techniques have been proposed for use on the Moon. Hydrogen reduction of iron oxide-bearing ...minerals in the lunar regolith, such as ilmenite, has long been suggested as a potential method for producing water on the Moon to support exploration. Generally, reduction of lunar regolith has been proposed and tested in gas-flowing systems which utilise pumps to re-circulate gases (herein described as dynamic systems), and have been trialled in terrestrial laboratory and simulated environments. However, such technologies have yet to be validated on the lunar surface. An alternative to the dynamic reactor is a static system which utilises a cold finger to condense water from the vapour phase, negating the need for a more complex system where gases are continuously pumped away. The PROSPECT Sample Processing and Analysis (ProSPA) instrument is one such static system that is to be used to measure volatiles in the lunar regolith as a payload onboard the Luna-27 lander. Previous work using a breadboard model of ProSPA led to the development and optimisation of a procedure for extracting water from ilmenite. The present work describes the application of these procedures to the reduction of a lunar simulant (NU-LHT-2M), a lunar meteorite (NWA 12592), and two Apollo soils (10084 and 60500). Three 45 mg samples of each material type were reacted in a furnace at 1000 °C for 4 h in the presence of approximately 420 mbar of hydrogen. All samples reduced to some extent, with the Apollo mare soil (10084) producing the highest average yield of 0.94 wt % O2; this compares favourably to the yields of ~3–4 wt % O2 by other more optimised demonstrations of O2 extraction from Apollo soils. Samples with higher ilmenite content produced higher yields, however, pyroxene and olivine within the samples also showed some minor reduction. The results demonstrate that a static system such as ProSPA is capable of reducing lunar regolith of various compositions and producing measurable yields of water. The technique is therefore appropriate for performing in situ resource utilisation experiments at the lunar surface. The simple and small scale technique is also appropriate for use in evaluating the grade of potential feedstock for the production of water by hydrogen reduction on the lunar surface.
•Oxygen extraction from lunar soil is performed with a ProSPA instrument breadboard.•Hydrogen reduction of lunar soil is feasible without a continuous gas pumping system.•Yields of 0.94 wt % O2 were recorded from lunar mare Apollo soil 10084
The ESA-ROSCOSMOS mission, Luna-27, scheduled for launch in 2023, includes a payload known as PROSPECT that is intended for sampling the polar lunar regolith through drilling, with subsequent ...analyses of the retrieved material. One of the aims of the analytical module, ProSPA, which is being developed at The Open University, is to identify and quantify the volatiles present in the extracted sample that are released by heating from ambient up to 1000 °C and analyzed by the mass spectrometers to assess their potential for in-situ resource utilization. The ProSPA design also includes a provision to test the extraction of water (and its associated oxygen) from lunar regolith by hydrogen reduction. Previous attempts at such extractions generally utilize a flow of hydrogen gas through the feedstock to efficiently extract water. However, in ProSPA, samples would be processed in a static mode, which leads to concerns that the reaction may be suppressed by inefficient removal of water vapor above the regolith. A first order theoretical assessment of the diffusion of gases in such a system was performed and suggested that water can diffuse through the system at an acceptable rate and be collected upon a cold finger thus enabling the reaction to proceed. Proof of concept experiments were successfully performed with a ProSPA breadboard using ilmenite samples up to ∼45 mg heated at 900 °C for 60 min. Subsequent heating of the cold finger, in vacuum, released 17 ± 1 μmol water from a 44.7 ± 0.5 mg sample, equating to a calculated yield of 0.6 ± 0.1 wt % oxygen, and a reduction extent of 5.8 ± 0.4%. A sample of mass 11.2 ± 0.5 mg had the greatest calculated yield of 1.4 ± 0.2 wt % oxygen, and this equates to a reduction extent of 12.9 ± 1.5%. SEM analyses of cross-sections of grains showed evidence of a reduction reaction inside the ilmenite grains with some showing greater reduction than others, indicating the reaction is limited by furnace dimensions, reaction kinetics and geometry. The results suggest that the ProSPA ISRU experiment should be capable of producing water, and therefore oxygen, by hydrogen reduction of ilmenite, ultimately this could be a viable technique for producing oxygen from ilmenite-containing lunar regolith with ProSPA.
•Hydrogen gas can reduce ilmenite in a ProSPA-type system to produce water.•Water can be condensed and released for quantification using a cold finger.•The ProSPA ISRU experiment is a useful prospecting technique.
Permanently shadowed regions (PSRs) are abundant at the lunar poles. They experience no direct sunlight and reach temperatures as low as 30 K. PSRs are of interest as evidence suggests that some may ...contain water ice (H2O/OH‐), which could provide a record of the evolution of volatiles in the inner solar system. This water ice is also a critical resource for life‐support systems and rocket propellant. A better understanding of mechanical properties of PSR regolith, such as its bearing capacity, will help optimize the design of future exploration rovers and landers. Thirteen boulder tracks were identified on the edge of, or inside, south polar lunar PSR enhanced imagery and used to estimate the strength of the PSR regolith at latitudes of 70° to 76° in sites with maximum annual temperatures of 65 to 210 K. PSR boulder track features are similar to those observed in highland, mare, and pyroclastic regions of the Moon, implying similar properties of the regolith. Measured features were used to estimate bearing capacity for PSR regolith at depths of ~0.28 to 4.68 m. Estimated bearing capacity values suggest that these PSRs may be somewhat stronger than highland and mare regions at depths of 0.28 to 1.00 m. Bearing capacity in these PSRs is statistically the same as those in other regions of the Moon at depths of 1.00 to 2.00 m. The results of this study can be used to infer bearing capacity as one measure for the trafficability of lower‐latitude PSRs of the type measured here.
Plain Language Summary
The polar regions of the Moon contain areas that never experience sunlight, known as permanently shadowed regions (PSRs). These regions are thought to contain uneven distributions of water ice deposits. To access PSRs and their possible water deposits, we must first understand the strength of the soil at these locations to safely traverse them. Thirteen boulder tracks were identified on the edge of, or within, PSRs in the lunar south polar region using images taken by the Lunar Reconnaissance Orbiter. These images were processed to enable the measurement of boulders and their associated tracks. The tracks identified within PSRs have similar appearances to those identified outside PSRs in other regions on the Moon. The strength of soil within PSRs was estimated from the measurements taken and was shown to be at least as strong as highland and mare regions of the Moon at relatively shallow depths, although the studied PSRs show no evidence for the presence of water ice. Analysis shows that PSRs of the type measured here should be able to bear rovers at depths of at least ~30 cm. In situ measurements are required to confirm and better understand the mechanical behavior of PSR regolith at shallow depths.
Key Points
Boulder tracks were measured from orbital imagery, and the bearing capacity of regolith in permanently shadowed regions was estimated
Regolith in permanently shadowed regions appears to be as strong as regolith found in other regions of the Moon
Boulder track measurements could be used to remotely estimate the traversability of PSRs for future exploration rovers
Image synthesis is used to generate synthetic CTs (sCTs) from on-treatment cone-beam CTs (CBCTs) with a view to improving image quality and enabling accurate dose computation to facilitate a ...CBCT-based adaptive radiotherapy workflow. As this area of research gains momentum, developments in sCT generation methods are difficult to compare due to the lack of large public datasets and sizeable variation in training procedures. To compare and assess the latest advancements in sCT generation, the SynthRAD2023 challenge provides a public dataset and evaluation framework for both MR and CBCT to sCT synthesis. Our contribution focuses on the second task, CBCT-to-sCT synthesis. By leveraging a multi-channel input to emphasize specific image features, our approach effectively addresses some of the challenges inherent in CBCT imaging, whilst restoring the contrast necessary for accurate visualisation of patients' anatomy. Additionally, we introduce an auxiliary fusion network to further enhance the fidelity of generated sCT images.
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