Does Medial Overhang of the Greater Trochanter Influence Femoral Stem Position During Cemented Hip Arthroplasty? A Retrospective Radiological Review

Purpose We investigate the effect that variation in the anatomy of the greater trochanter (GT), in particular the medial overhang, can have on femoral stem alignment in total hip arthroplasty (THA). Methods Pre- and post-operative anteroposterior pelvic radiographs of 576 consecutive patients undergoing THA were retrospectively analysed. Medial overhang of the GT relative to the lateral femur diaphysis was measured. The femoral morphology was classified according to Dorr classification. The alignment of the femoral stem axes on post-operative radiographs was recorded. Results Following exclusions, 500 THAs performed by six surgeons all using the same cemented polish tapered stems were analysed: 320 THAs were performed via the posterior-lateral approach and 180 via the direct-lateral approach. Mean stem varus was 0.53° (range: -7 to 7°). Mean medial overhang was 21 mm (range: 8-43 mm). An overhang of 30 mm had a mean varus of 2.33°. Those with an overhang of 30 mm. One-way analysis of variance comparison of these groups returned a p-value of <0.0001. Dorr type A femora had a mean varus of 0.52°, Dorr B had a mean varus of 0.54° and Dorr C had a mean varus of 0.46°. The posterior-lateral approach had a mean varus of 1.05° (range: -7 to 7°) compared to -0.40° (range: -5 to 5°) for direct-lateral approach. The t-test comparing approach was p < 0.0001. Discussion The extent of medial overhang of the GT can adversely affect the final stem position in THA, resulting in a statistically significant increase in mean stem varus. There is a linear relationship between stem position and GT overhang, with an increased chance of significant varus malposition (44.4% with >30 mm of overhang). Conclusions Scrutiny of pre-operative radiographs to determine high-risk patients is important, and we propose a classification system of GT anatomy to aid assessment

Sedimentological study of cold-water coral mounds on Pen Duick Escarpment (Gulf of Cadiz): preliminary results of the MD169 cruise

Cold-water corals are widely distributed along the Moroccan margin in the Northeast Atlantic Ocean. Within the Gulf of Cadiz mud volcanoes, submarine ridges and steep fault escarpments occur, which favour the settlement of scleractinians and build up coral mounds. One of these sites is the Pen Duick Escarpment, situated in the El Arraiche mud volcano field, 35 km offshore the city of Larache. Pen Duick Escarpment is a 6 km long, SSE-NNW oriented, 80 to 125 m high wall with a southwest-facing slope of 8 to 12°. Up to now, 15 coral mounds were recognized on top of the escarpment with an average estimated elevation of 15 m. Although cold-water corals are a common feature on the adjacent cliffs, mud volcanoes and seafloor, no actual living coral has been observed.This study is based upon three on-mound gravity cores (Alpha, Beta and Gamma mound) acquired by R/V Marion Dufresne in 2008 (MD169). Each mound was cored at least twice to recover both a core for biogeochemical and microbial studies, and another core for sedimentological purposes, in order to link both processes. The sedimentological cores were analysed using different techniques (medical CT scanning, XRF, U/Th dating, stable isotopes, grain-size analysis) in order to obtain a holistic view on the build-up of a mound. The coring, together with present-day seabed observations, revealed the architectural importance of open coral rubble plates in the role of mound building. These graveyards act not only as sediment trap but also as microhabitat for a wide range of benthic organisms

Fast Leakage Assessment

We describe a fast technique for performing the computationally heavy part of leakage assessment, in any statistical moment (or other property) of the leakage samples distributions. The proposed technique outperforms by orders of magnitude the approach presented at CHES 2015 by Schneider and Moradi. We can carry out evaluations that before took 90 CPU-days in 4 CPU-hours (about a 500-fold speed-up). As a bonus, we can work with exact arithmetic, we can apply kernel-based density estimation methods, we can employ arbitrary pre-processing functions such as absolute value to power traces, and we can perform information-theoretic leakage assessment. Our trick is simple and elegant, and lends itself to an easy and compact implementation. We fit a prototype implementation in about 130 lines of C code

Efficiency assessment of hybrid coatings for natural building stones : advanced and multi-scale laboratory investigation

The efficiency of a hybrid patented consolidant (PAASi) and two commercially available hybrid coatings (a consolidant named AlSiX and a hydrophobic product named WS3) properly modified was assessed on a calcarenite substrate. Test routines based on standard recommendations were first applied to evaluate the performances of the consolidant and protective treatments, while the investigation of additional aspects such as penetration depth and interaction with the substrate was achieved by a multi-scale approach based on classic intrusion methods (mercury intrusion porosimetry) and Drilling Resistance Measurement System (DRMS), combined with non-invasive imaging techniques (X-ray computed micro-tomography and neutron radiography) and small angle neutron scattering (SANS). A distinct interaction of the products with the pore network of the stone was quantified in the range 0.007–200 µm. Their effects on capillary water absorption were also visualized with neutron imaging. The suitability of the products on the selected substrate was discussed, highlighting also how the applied routine can support conservation material studies. The results indicated that the Al-Si-based product led to unwanted effects. Alternative application methods and/or curing procedures have to be explored to overtake these undesirable changes. On the contrary, the polyamidoamine-based product seemed to be more suitable for calcarenite substrates conservation. The performances of the hydrophobic coating, when used in combination with consolidants, were strictly influenced by the pre-consolidation of the substrate

Multi-scale laboratory routine in the efficacy assessment of conservative products for natural stones

The evaluation of conservative treatments’ efficacy on natural building stones are usually based on standard recommendation routines finalized to evaluate compatibility and harmfulness of products in turn of the substrate. However, the visualization and the quantification of products inside pore structure of natural stones is not immediate through standard tests, so that imaging and advanced techniques are recently proposed in material conservation field to improve knowledge on penetration depth, modification of pore-air interface at different scale and monitor dynamic absorption processes. Moreover, natural stones are usually characterized by complex structure, which changes due to conservative treatments have to be inspected at different scale (from micrometer to nanometer). In this prospective, the assessment of laboratory practices able to integrate multiscale methods and give back a complete overview on interaction between new conservative formulates and natural stones is of high interest. In this paper, we propose a methodological routine for efficacy assessment of conservative products, incorporating classical and innovative nondestructive techniques. Validation of the workflow has been verified on a high porous natural stone treated with new hybrid formulates appropriately customized for conservation issues. • The study intends to add new insights on problems related to consolidation of high porous carbonate stone, application methods in consolidating natural stones and methods to evaluate efficacy of new products.• A multi-scale laboratory investigation procedure is proposed by integrating standard and innovative nondestructive methods. Merits and limits of each applied method are discussed during validation.• The possibility to incorporate standard routines and/or substitute destructive testing with non-destructive ones seem to be a valid alternative to evaluate efficiency and monitor behavior of stones treated with consolidating products

The taste of diatoms: the role of diatom growth phase characteristics and associated bacteria for benthic copepod grazing

The interactions between primary producers and their consumers are of particular interest for the overall functioning of marine ecosystems. The biochemical composition of the organisms involved affects the efficiency of energy transfer in marine food webs. In addition to top-down control by grazers, bottom-up control of these interactions by primary producers and associated bacteria has recently received more attention. Planktonic copepods selectively feed on older diatom cells, a behaviour regulated by changes in exometabolites around diatoms. To test whether this also applies to benthic copepods, Seminavis robusta cells in lag, exponential and stationary growth phases were biochemically screened, and the diversity of associated bacteria was assessed. The diatoms were subsequently 13C prelabelled and offered to the harpacticoid copepod Microarthridion littorale in a grazing experiment. Harpacticoid copepods incorporated more carbon from younger diatom cells in the lag growth phase, which might be based on (1) biochemical differences of diatom cells in different growth phases and (2) the bacteria associated with the diatoms. The younger diatom cells were characterised by a higher C:N ratio and more extracellular polymer secretions but a lower fatty acid content. The bacterial community on these cells differed from those on cells in the later growth phases. Our results thus suggest that the feeding strategies of benthic harpacticoid copepods differ from those of calanoid copepods. This outcome can be explained by the tight contact between benthic copepods and the typical carbon and bacteria-rich biofilm on sediments

Durability of the Indian Kandla Grey sandstone under Western European climatic conditions

An increasing amount of imported natural building stones are being used in Western Europe, often as a replacement of more traditional, local building stones. Unlike for these traditional stones, which have been used under the prevailing climatic conditions in Western Europe, the durability of these imported stones is largely unknown. Therefore, it is essential to study their behaviour under these climatic conditions in order to predict their weathering resistance. The chemical and structural properties of these new building materials need to be determined and their behaviour under changing environmental conditions needs to be studied. When these materials are being used in Western Europe, they have to resist to significant mechanical stresses due to the imbibition of de-icing salt solutions. These de-icing salts are very frequently used during winter in Western Europe, while temperature fluctuates between freezing and thaw conditions. In this research, focus has been laid on the multi-disciplinary characterization of the compact Kandla Grey layered sandstone. This stone is recently frequently imported from India to Belgium. Besides traditional techniques, (according to European Standars for natural stone testing) highly advanced research techniques such as µ-XRF and HRXCT were used to characterize and monitor the changes under different external conditions such as freezing, thawing and salt crystallization. The results of this study demonstrate that the structural properties of the laminations inside Kandla Grey have an influence on the resistance of the stone to frost and salt weathering. Based on these results, it can be concluded that Kandla Grey can be vulnerable to these types of weathering under the current climatic conditions in Western Europe