Posterior mini-incision total hip arthroplasty controls the extent of post-operative formation of heterotopic ossification.

Heterotopic ossification (HO) is the formation of bone at extra-skeletal sites. Reported rates of HO after hip arthroplasty range from 8 to 90 %; however, it is only severe cases that cause problems clinically, such as joint stiffness. The effects of surgical-related controllable intra-operative risk factors for the formation of HO were investigated. Data examined included gender, age of patient, fat depth, length of operation, incision length, prosthetic fixation method, the use of pulsed lavage and canal brush, and component size and material. All cases were performed by the same surgeon using the posterior approach. A total of 510 cases of hip arthroplasty were included, with an overall rate of HO of 10.2 %. Longer-lasting operations resulted in higher grades of HO (p = 0.047). Incisions >10 cm resulted in more widespread HO formation (p = 0.021). No further correlations were seen between HO formation and fat depth, blood loss, instrumentation, fixation methods or prosthesis material. The mini-incision approach is comparable to the standard approach in the aetiology of HO formation, and whilst the rate of HO may not be controllable, a posterior mini-incision approach can limit its extent

Lattice strain causes non-radiative losses in halide perovskites

Halide perovskites are found to exhibit strain patterns over large areas, which influences the lifetimes of charge carriers.EPSR

Prospective Randomized Controlled Trial to Analyze the Effects of Intermittent Pneumatic Compression on Edema Following Autologous Femoropopliteal Bypass Surgery

Background: Patients who undergo autologous femoropopliteal bypass surgery develop postoperative edema in the revascularized leg. The effects of intermittent pneumatic compression (IPC) to treat and to prevent postreconstructive edema were examined in this study. Methods: In a prospective randomized trial, patients were assigned to one of two groups. All patients suffered from peripheral arterial disease, and all were subjected to autologous femoropopliteal bypass reconstruction. Patients in group 1 used a compression stocking (CS) above the knee exerting 18 mmHg (class I) on the leg postoperatively for 1 week (day and night). Patients in group 2 used IPC on the foot postoperatively at night for 1 week. The lower leg circumference was measured preoperatively and at five postoperative time points. A multivariate analysis was done using a mixed model analysis of variance. Results: A total of 57 patients were analyzed (CS 28; IPC 29). Indications for operation were severe claudication (CS 13; IPC 13), rest pain (10/5), or tissue loss (7/11). Revascularization was performed with either a supragenicular (CS 13; IPC10) or an infragenicular (CS 15; IPC 19) autologous bypass. Leg circumference increased on day 1 (CS/IPC): 0.4%/2.7%, day 4 (2.1%/6.1%), day 7 (2.5%/7.9%), day 14 (4.7%/7.3%), and day 90 (1.0%/3.3%) from baseline (preoperative situation). On days 1, 4, and 7 there was a significant difference in leg circumference between the two treatment groups. Conclusions: Edema following femoropopliteal bypass surgery occurs in all patients. For the prevention and treatment of that edema the use of a class I CS proved superior to treatment with IPC. The use of CS remains the recommended practice following femoropopliteal bypass surgery

Paleotemperature Proxies from Leaf Fossils Reinterpreted in Light of Evolutionary History

Present-day correlations between leaf physiognomic traits (shape and size) and climate are widely used to estimate paleoclimate using fossil floras. For example, leaf-margin analysis estimates paleotemperature using the modern relation of mean annual temperature (MAT) and the site-proportion of untoothed-leaf species (NT). This uniformitarian approach should provide accurate paleoclimate reconstructions under the core assumption that leaf-trait variation principally results from adaptive environmental convergence, and because variation is thus largely independent of phylogeny it should be constant through geologic time. Although much research acknowledges and investigates possible pitfalls in paleoclimate estimation based on leaf physiognomy, the core assumption has never been explicitly tested in a phylogenetic comparative framework. Combining an extant dataset of 21 leaf traits and temperature with a phylogenetic hypothesis for 569 species-site pairs at 17 sites, we found varying amounts of non-random phylogenetic signal in all traits. Phylogenetic vs. standard regressions generally support prevailing ideas that leaf-traits are adaptively responding to temperature, but wider confidence intervals, and shifts in slope and intercept, indicate an overall reduced ability to predict climate precisely due to the non-random phylogenetic signal. Notably, the modern-day relation of proportion of untoothed taxa with mean annual temperature (NT-MAT), central in paleotemperature inference, was greatly modified and reduced, indicating that the modern correlation primarily results from biogeographic history. Importantly, some tooth traits, such as number of teeth, had similar or steeper slopes after taking phylogeny into account, suggesting that leaf teeth display a pattern of exaptive evolution in higher latitudes. This study shows that the assumption of convergence required for precise, quantitative temperature estimates using present-day leaf traits is not supported by empirical evidence, and thus we have very low confidence in previously published, numerical paleotemperature estimates. However, interpreting qualitative changes in paleotemperature remains warranted, given certain conditions such as stratigraphically closely-spaced samples with floristic continuity

Lattice strain causes non-radiative losses in halide perovskites

Halide perovskites are found to exhibit strain patterns over large areas, which influences the lifetimes of charge carriers.EPSR

Elucidating and Mitigating Degradation Processes in Perovskite Light-Emitting Diodes

Halide perovskites have attracted substantial interest for their potential as disruptive display and lighting technologies. However, perovskite light-emitting diodes (PeLEDs) are still hindered by poor operational stability. A fundamental understanding of the degradation processes is lacking but will be key to mitigating these pathways. Here, we use a combination of in operando and ex-situ measurements to monitor the performance degradation of (Cs0.06FA0.79MA0.15)Pb(I0.85Br0.15)3 PeLEDs over time. Through device, nanoscale cross-sectional chemical mapping, and optical spectroscopy measurements, we reveal that the degraded performance arises from an irreversible accumulation of bromide content at one interface, which leads to barriers to injection of charge carriers and thus increased non-radiative recombination. We impede this ionic segregation by passivating the perovskite films with potassium halides, which immobilizes the excess halide species. The passivated PeLEDs show enhanced external quantum efficiency (EQE) from 0.5 to 4.5% and, importantly, show significantly enhanced stability, with minimal performance roll-off even at high current densities (> 200 mA/cm2). The decay half-life for the devices under continuous operation at peak EQE increases from <1 hour to ~15 hours through passivation, and ~200 hours under pulsed operation. Our results provide generalized insight into degradation pathways in PeLEDs and highlight routes to overcome these challenges.The authors thank the Engineering and Physical Sciences Research Council (EPSRC) for support (EP/R023980/1). Z.A.-G. acknowledges funding from a Winton Studentship, and ICON Studentship from the Lloyd’s Register Foundation. S.D.S acknowledge the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (HYPERION, Grant Agreement No. 756962), and the Royal Society and Tata Group (UF150033). M.A.-J. thanks Cambridge Materials Limited, Wolfson College, University of Cambridge, and EPSRC for their funding and technical support. F.U.K. thanks the Jardine Foundation and Cambridge Trust for a doctoral scholarship. This work was carried out with the support of the Diamond Light Source, instrument I09 (proposal SI22668-1). The research leading to this result has been supported by the project CALIPSOplus under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. H.R., G.J.M. and U.B.C. acknowledge research funding from the Swedish Research Council (Grant nos. VR 2018-04125, 2018-06465, and 2018-04330), the Swedish Foundation for Strategic Research (Project no. RMA15-0130) and the Swedish Energy Agency (Grant no. P43549-1)

Lattice strain causes non-radiative losses in halide perovskites

Halide perovskites are promising semiconductors for inexpensive, high-performance optoelectronics. Despite a remarkable defect tolerance compared to conventional semiconductors, perovskite thin films still show substantial microscale heterogeneity in key properties such as luminescence efficiency and device performance. However, the origin of the variations remains a topic of debate, and a precise understanding is critical to the rational design of defect management strategies. Through a multi-scale investigation-combining correlative synchrotron scanning X-ray diffraction and time-resolved photoluminescence measurements on the same scan area-we reveal that lattice strain is directly associated with enhanced defect concentrations and non-radiative recombination. The strain patterns have a complex heterogeneity across multiple length scales. We propose that strain arises during the film growth and crystallization and provides a driving force for defect formation. Our work sheds new light on the presence and influence of structural defects in halide perovskites, revealing new pathways to manage defects and eliminate losses

Climatic reconstruction of two Pliocene floras from Mexico

The role that climate plays in influencing the physiognomy of modern and fossil plant communities is widely acknowledged and forms the basis for several palaeoclimate proxies. In this work, both univariate Leaf Margin Analysis and multivariate Climate/Leaf Analysis Multivariate Program (CLAMP) were used for the climatic reconstruction of two fossil localities of the Atotonilco El Grande Formation. Using the predominantly North American and Asian calibration data set PHYSG3BRC, supplemented with new African material, results from two sites, Los Baños (present position 20°18′18″N, 98°42′44.4″W) and Sanctorum (20°18′18.5″N and 98°46′52.2″W), indicate that during the Pliocene a mesothermal climate existed with mean annual temperatures between 12 and 22°C, with the most likely being approximately 15°C, and a mean annual temperature range of 21°C. A distinct seasonal variation in rainfall is evident with a mean annual relative humidity of 60–70%. Differences between the sites can be explained by differences in depositional regime and spatial heterogeneity in the predominantly Quercus-dominated woodland. The continuous subsequent uplift of the Sierra Madre Oriental, the resulting development of a rain shadow, and the eventual disappearance of a palaeolake appear to have caused a transition to the modern xerophytic shrub vegetation