Dissociation of liner from cup in THA: does liner damage affect the risk of dissociation?

INTRODUCTION A rare catastrophic failure of modular component Total Hip Arthroplasty is dissociation between liner and cup, which has been associated with component malposition and/or impingement and seems to be more frequently associated with the Pinnacle system. The goal of this study was to evaluate the resistance of a polyethylene liner to lever-out-forces of the Pinnacle locking mechanism and the locking mechanisms of two other current cup/liner systems using a standardized testing method (ASTM). MATERIALS AND METHODS Five of each of the following cups were evaluated with their corresponding polyethylene liners: Pinnacle Multihole cup with and without intact anti-rotation tabs (ART's); Allofit-S-Alloclassic and Plasmafit Plus7 cups. The ASTM test set-up was used to evaluate the lever-out force resulting in liner dissociation for each construct. RESULTS The Pinnacle construct with intact ARTs required the greatest force (F) to achieve dissociation (263.2 ± 79.2 N) followed by the Plasmafit Plus7 (185.8 ± 36.9 N) and the Allofit-S (101.4 ± 35.3 N) constructs, respectively. However, after removal of the ARTs, the Pinnacle system required the least force to achieve dissociation (75.1 ± 22.2 N) (p < 0.001). CONCLUSIONS The intact Pinnacle system appeared the most stable in lever-out tests when compared to the other systems. However, after removal of the ARTs, the Pinnacle system required the least force for dissociation, consistent with locking mechanism failure, and suggesting that the ARTs are a critical component of the locking mechanism. Our findings are consistent with the clinical experience of dissociated Pinnacle constructs displaying damaged or missing ARTs, and that damage to these may increase risk of liner dissociation

Sustainability assessment of the production of microbial bio-based surfactants

Related to the development of production processes for microbial bio-based surfactants like rhamnolipids and mannosylerythritol lipids a sustainability assessment was carried out within the project Bio². Developments at lab-scale and technical scale built the base for an industrial design scenario of different process chains, whereby exemplary co-products of sugar beet processing were used as substrates. Environmental impacts, economic issues and social risks of defined process chains allowed a classification of different microbial surfactant production options by the assessment of the three dimensions of sustainability. The generated results work as an indicator for further development, provide insights to potential hotspots and allow the estimation of future market positions

Environmental competitiveness evaluation by life cycle assessment for solid fuels generated from Sida hermaphrodita biomass

As part of a comprehensive evaluation of the use of Sida hermaphrodita (hereafter referred to as Sida) biomass as a solid biofuel, a life cycle assessment (LCA) according to ISO 14040/14044 was carried out by means of a suitable cradle-to-gate system design. The supply and use of chips, pellets and briquettes was studied by internal and external comparisons to show competitiveness and improvement options. The results show fewer differences within the Sida process chain designs but larger distinctions to compared alternative biofuels such as wood or Miscanthus pellets. A major finding is that Sida process chains cause lower environmental impacts in comparison with alternative biofuels. The study identified hot spots within the Sida process chains and starting points for further improvement. A sensitivity analysis of important parameters, such as specific yield or heating values was performed. Because there are no similar investigations on the environmental impact of Sida used as a biogenic solid fuel to date this manuscript presents first results. So far, the results indicate that Sida provides a more sustainable option for the use of biomass in combustion processes in relation to environmental impacts

Environmental impacts of biosurfactant production based on substrates from the sugar industry

Regarding the omnipresent topic of climate change, establishing a bio-economy appears reasonable, but requires critical analysis of its products. This project-specific study (project Bio²) presents previously unknown environmental impacts caused by the novel production of biosurfactants (rhamnolipids (RL) and mannosylerythritol lipids (MEL)) based on substrates from sugar industry (molasses and sugar beet pulp) using Life Cycle Assessment (LCA). Identifying critical impacts and processes (e.g., extraction agent production) reveals optimization potentials for the considered forward-looking process designs. Based on surfactants’ specific cleaning performance, environmental impacts vary substantially for RL and MEL. Primary causes of MEL productions’ lower environmental impacts are advantageous microbial properties and process designs. Substrate choice does not play an essential role. An analysis of realistic yield changes and comparisons with conventional surfactants sharpens the view on the development position of the chosen surfactants. In particular MEL shows environmental benefits compared to today’s oleo-/petrochemical produced surfactants. Identified optimization options (e.g., increased agent recycling) and yield increases could strengthen especially the advantages of MEL. Summarizing, the results show advantages of MEL compared to RL to some degree, indicate weak points of current processes and highlight favorable options for future design of RL and MEL production, regarding their environmental impact

Life cycle costing approaches of fuel cell and hydrogen systems: A literature review

Hydrogen is a versatile energy carrier which can be produced from variety of feedstocks, stored and transported in various forms for multi-functional end-uses in transportation, energy and manufacturing sectors. Several regional, national and supra-national climate policy frameworks emphasize the need, value and importance of Fuel cell and Hydrogen (FCH) technologies for deep and sector-wide decarbonization. Despite these multi-faceted advantages, familiar and proven FCH technologies such as alkaline electrolysis and proton-exchange membrane fuel cell (PEMFC) often face economic, technical and societal barriers to mass-market adoption. There is no single, unified, standardized, and globally harmonized normative definition of costs. Nevertheless, the discussion and debates surrounding plausible candidates and/or constituents integral for assessing the economics and value proposition of status-quo as well as developmental FCH technologies are steadily increasing—Life Cycle Costing (LCC) being one of them, if not the most important outcome of such exercises.To that end, this review article seeks to improve our collective understanding of LCC of FCH technologies by scrutinizing close to a few hundred publications drawn from representative databases—SCOPUS and Web of Science encompassing several tens of technologies for production and select transportation, storage and end-user utilization cases. This comprehensive review forms part of and serves as the basis for the Clean Hydrogen Partnership funded SH2E project, whose ultimate goal is the methodical development a formal set of principles and guardrails for evaluating the economic, environmental and social impacts of FCH technologies. Additionally, the SH2E projects will also facilitate the proper comparison of different FCH technologies whilst reconciling range of technologies, methodologies, modelling assumptions, and parameterization found in existing literature

Femoral Cementation in Knee Arthroplasty-A Comparison of Three Cementing Techniques in a Sawbone Model Using the ATTUNE Knee.

Femoral component loosening is a rare but severe complication in total knee arthroplasty. Former studies have repeatedly demonstrated radiolucent lines behind the ventral and dorsal anchoring shields of the femoral components, which has led us to investigate this matter further. Therefore, three different cementing techniques were tested in a group of nine Sawbone samples each. These differed in the amount of cement applied on the femoral component as well as in the pressure application. Computed tomography was performed to evaluate and classify the cement penetration into the bone adjacent to the prosthesis according to the zones defined by the Knee Society scoring system. The results show significantly deeper cement penetration in all zones when a pressurizer is used. In the other two groups, no significant difference in the dorsal bevel cement penetration was noted. Additionally, no difference in ventral and dorsal cement penetrations (Zones 1 and 4) was delineated. In contrast, there was a significant difference in both the ventral bevel (Zone 2) as well as the distal anchoring surface (Zones 5-7). The use of a pressurizer results in greater cement penetration into all anchoring areas. Completely covering the component back surface results in a significantly higher penetration, which is mainly due to differences in volume. These data show significantly improved cementation results when using a pressurizer. Whether this improves the biomechanical properties and ultimately the revision rate requires further investigation

Integration of genetic and process engineering for optimized rhamnolipid production using pseudomonas putida

Rhamnolipids are biosurfactants produced by microorganisms with the potential to replace synthetic compounds with petrochemical origin. To promote industrial use of rhamnolipids, recombinant rhamnolipid production from sugars needs to be intensified. Since this remains challenging, the aim of the presented research is to utilize a multidisciplinary approach to take a step toward developing a sustainable rhamnolipid production process. Here, we developed expression cassettes for stable integration of the rhamnolipid biosynthesis genes into the genome outperformed plasmid-based expression systems. Furthermore, the genetic stability of the production strain was improved by using an inducible promoter. To enhance rhamnolipid synthesis, energy- and/or carbon-consuming traits were removed: mutants negative for the synthesis of the flagellar machinery or the storage polymer PHA showed increased production by 50%. Variation of time of induction resulted in an 18% increase in titers. A scale-up from shake flasks was carried out using a 1-L bioreactor. By recycling of the foam, biomass loss could be minimized and a rhamnolipid titer of up to 1.5 g/L was achieved without using mechanical foam destroyers or antifoaming agents. Subsequent liquid–liquid extraction was optimized by using a suitable minimal medium during fermentation to reduce undesired interphase formation. A technical-scale production process was designed and evaluated by a life-cycle assessment (LCA). Different process chains and their specific environmental impact were examined. It was found that next to biomass supply, the fermentation had the biggest environmental impact. The present work underlines the need for multidisciplinary approaches to address the challenges associated with achieving sustainable production of microbial secondary metabolites. The results are discussed in the context of the challenges of microbial biosurfactant production using hydrophilic substrates on an industrial scale