Abstract The surgical reconstruction of Charcot deformity can be a challenge for foot and ankle surgeons. Consensus is lacking among surgeons regarding the best method of surgical fixation to be used ...in reconstruction, and clear strong evidence is also lacking in published studies. We undertook a systematic review of electronic databases and other relevant sources in an attempt to better understand the complications and outcomes associated with internal and external fixation for Charcot foot and ankle reconstruction. A total of 23 level 4 studies with 616 procedures were identified. Of these, 12 studies with 275 procedures used internal fixation, and 11 studies with 341 procedures used external fixation. The odds of a successful outcome with internal fixation was 6.86. The odds of a successful outcome with external fixation was 13.20 (odds ratio 0.52, 95% confidence interval 0.30 to 0.90). The odds of success for internal fixation was 0.52 times as likely as the odds of success with external fixation. Because the odds ratio did not include 1, this difference was statistically significant at the p < .05 level. An identified trend was that external fixation was used more often in cases deemed to be difficult by the surgeon preoperatively. These findings could prove helpful to foot and ankle surgeons when making decisions regarding fixation for Charcot reconstruction.
Quality standards (QS) for dissolved metals in freshwaters have been proposed under the European Water Framework Directive (WFD) and are based mainly upon laboratory ecotoxicity data. Uncertainties ...remain about laboratory-to-field extrapolation to establish QS that are neither over- nor underprotective. Freshwater benthic macroinvertebrates are a group of organisms of known sensitivity to heavy metals. We analyzed a dataset from England and Wales of dissolved metal concentrations (cadmium, chromium, copper, iron, nickel, lead, and zinc) and associated benthic invertebrate community metrics, using piecewise regression, quantile regression, and information on metal concentra tions consistent with good quality status. Analysis of these field data suggests that dissolved metal QS proposed under the WFD are similar to metal concentrations in rivers associated with unimpaired benthic invertebrate as semblages in England and Wales. The only exceptions to this are QS for iron and zinc, where use of relatively large assessment factors leads to standards that are substantially below concentrations associated with impaired invertebrate assemblages in the field.
There is generally a lack of saltwater ecotoxicity data for risk assessment purposes, leaving an unknown margin of uncertainty in saltwater assessments that utilize surrogate freshwater data. ...Consequently, a need for sound scientific advice on the suitability of using freshwater data to extrapolate to saltwater effects exists. Here we use species sensitivity distributions to determine if freshwater datasets are adequately protective of saltwater species assemblages for 21 chemical substances. For ammonia and the metal compounds among these data, freshwater data were generally protective because freshwater organisms tended to be more sensitive. In contrast, for pesticide and narcotic compounds, saltwater species tended to be more sensitive and a suitable uncertainty factor would need to be applied to surrogate freshwater data. Biological and physicochemical factors contribute to such differences in freshwater and saltwater species sensitivities, but the species compositions of datasets used are also important.
Scaled sandbox models were used to investigate the 4D evolution of pull-apart basins formed above underlapping releasing stepovers in both pure strike-slip and transtensional basement fault systems. ...Serial sectioning and 3D volume reconstruction permitted analysis of the full 3D fault geometries. Results show that very different pull-apart basins are developed in transtension compared to pure strike-slip. Both types of models produced elongate, sigmoidal to rhomboidal pull-apart systems, but the transtensional pull-apart basins were significantly wider and uniquely developed a basin margin of en-echelon oblique-extensional faults. Dual, opposing depocentres formed in the transtensional model whereas a single, central depocentre formed in pure strike-slip. In transtension, a distinct narrow graben system formed above the principal displacement zones (PDZs). Cross-basin fault systems that linked the offset PDZs formed earlier in the transtensional models.
Sequential model runs to higher PDZ displacements allowed the progressive evolution of the fault systems to be evaluated. In cross-section, transtensional pull-aparts initiated as asymmetric grabens bounded by planar oblique-extensional faults. With increasing displacement on the PDZs, basin subsidence caused these faults to become concave-upwards and lower in dip angle due to fault block collapse towards the interior of the basin. In addition, strain partitioning caused fault slip to become either predominantly extensional or strike-slip. The models compare closely with the geometries of natural pull-apart basins including the southern Dead Sea fault system and the Vienna Basin, Austria.
The feasibility and added value of an ecosystem services approach in retrospective environmental risk assessment were evaluated using a site-specific case study in a lowland UK river. The studied ...water body failed to achieve good ecological status temporarily in 2018, due in part to the exceedance of the environmental quality standard (annual average EQS) for zinc. Potential ecosystem service delivery was quantified for locally prioritised ecosystem services: regulation of chemical condition; maintaining nursery populations and habitats; recreational fishing; nature watching. Quantification was based on observed and expected taxa or functional groups within WFD biological quality elements, including macrophytes, benthic macroinvertebrates and fish, and on published functional trait data for constituent taxa. Benthic macroinvertebrate taxa were identified and enumerated before, during and after zinc EQS exceedance, enabling a generic retrospective risk assessment for this biological quality element, which was found to have good ecosystem service potential. An additional targeted risk assessment for zinc was based on laboratory-based species sensitivity distributions normalised using biotic-ligand modelling to account for site-specific, bioavailability-corrected zinc exposure. Risk to ecosystem services for diatoms (microalgae) was found to be high, while risks for benthic macroinvertebrates and fish were found to be low. The status of potential ecosystem service delivery (ESD) by fish was equivalent to high ecological status defined under the WFD, while ESD was higher for benthic macroinvertebrates than defined by WFD methods. The illustrated ecosystem services approach uses readily available data and adds significantly to the taxonomic approach currently used under the WFD by using functional traits to evaluate services that are prioritised as being important in water bodies. The main shortcomings of the illustrated approach were lack of: representation of bacteria and fungi; WFD predicted species lists for diatoms and macrophytes; site-specific functional trait data required for defining actual (rather than potential) ecosystem service delivery.
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•We present a site-specific case study based around the Water Framework Directive (WFD).•WFD measurement endpoints for ecological receptors were linked to ecosystem services.•The measured status of ecosystem services was compared to WFD reference values.•The risk of zinc to ecosystem service delivery was assessed retrospectively.•Risk to ecosystem service delivery was equivalent or lower than WFD ecological status.
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