252 research outputs found
Is the rate of revision of 36 mm metal-on-metal total hip arthroplasties with Pinnacle acetabular components related to the year of the initial operation? An interrupted time-series analysis using data from the national joint registry for England and Wales
No full textAims The aim of this study was to determine whether the rates of revision for metal-on-metal (MoM) total hip arthroplasties (THAs) with Pinnacle components varied according to the year of the initial operation, and compare these with the rates of revision for other designs of MoM THA. Patients and Methods Data from the National Joint Registry for England and Wales included 36 mm MoM THAs with Pinnacle acetabular components which were undertaken between 2003 and 2012 with follow-up for at least five years (n = 10 776) and a control group of other MoM THAs (n = 13 817). The effect of the year of the primary operation on all-cause rates of revision was assessed using Cox regression and interrupted time-series analysis. Results For MoM THAs involving Pinnacle components, those undertaken between 2007 and 2012 had higher rates of revision compared with those undertaken between 2004 and 2006 (hazard ratio (HR) 2.01; 95% confidence interval (CI) 1.57 to 2.57; p < 0.001). For THAs undertaken during and after 2007, the number of revisions per 1000 implant-years at risk significantly increased by 5.20 (95% CI 0.52 to 9.89; p = 0.033) compared with those undertaken before this time. In the control group, THAs undertaken between 2007 and 2012 also had higher rates of revision (HR 1.77; 95% CI 1.49 to 2.10; p < 0.001), with revisions per 1000 implant-years for those undertaken during and after 2007 significantly increasing by 6.13 (95% CI 1.42 to 10.83; p = 0.016). Conclusion The five-year revision rates were significantly increased for all primary MoM THAs undertaken from 2007 onwards. Contrary to recent reports, this finding was not specific to those involving Pinnacle acetabular components and may be explained by increased surveillance and recent lowering of the threshold for revision.</p
A new facile solvometallurgical leaching method for the selective Co dissolution & recovery from hard metals waste
No full textHard Metals (HM) production plays a fundamental role in economy and technological development. Due to the criticality of its main raw materials, W and Co, a sustainable HM waste recycling is hence desirable for both environmental and economic reasons and strongly encouraged by European waste management directives. This work describes a new solvometallurgical leaching method based on diluted maleic acid (H2Mal) ethanolic solutions, which demonstrated to couple effectiveness in materials enhancement from HM waste, with mildness and sustainability of operative conditions. Specifically, H2Mal (0.5 M, EtOH) selectively and quantitatively leached Co trapped within WC-Co powders, to afford [Co(HMal)2(H2O)4] complex within 4 h at room temperature and leaving WC unreacted and ready for re-employment in HM manufacturing. Characterization of the resultant materials i.e. treated powders (SEM-EDS, p-XRD, ICP-OES) and Co-leaching solutions (ICP-OES), confirmed the near quantitative Co removal as well as the possibility to finely tune the composition of WC-Co mixtures. Parameters for best leaching conditions, i.e. time and liquid-to-solid ratio, were obtained. A scale-up experiment addressed to test the leaching conditions and the quality of the recycled material is also described. The quality of the recycled material for direct re-employment in HM manufacturing was validated by Metallurgical Quality Control, to good effect. Finally, preliminary experiments on cobalt metal recovery from the metal complex by electrowinning and by quantitative precipitation as CoCO3 were performed with encouraging results: a step forward resources circularity
Outcomes following revision surgery performed for adverse reactions to metal debris in non-metal-on-metal hip arthroplasty patients:Analysis of 185 revisions from the National Joint Registry for England and Wales
No full textFew studies have assessed outcomes following non-metal-on-metal hip arthroplasty (non-MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD). We assessed outcomes following non-MoMHA revision surgery performed for ARMD, and identified predictors of re-revision.We performed a retrospective observational study using data from the National Joint Registry for England and Wales. All non-MoMHAs undergoing revision surgery for ARMD between 2008 and 2014 were included (185 hips in 185 patients). Outcome measures following ARMD revision were intra-operative complications, mortality and re-revision surgery. Predictors of re-revision were identified using Cox regression.Intra-operative complications occurred in 6.0% (n = 11) of the 185 cases. The cumulative four-year patient survival rate was 98.2% (95% CI 92.9 to 99.5). Re-revision surgery was performed in 13.5% (n = 25) of hips at a mean time of 1.2 years (0.1 to 3.1 years) following ARMD revision. Infection (32%; n = 8), dislocation/subluxation (24%; n = 6), and aseptic loosening (24%; n = 6) were the most common re-revision indications. The cumulative four-year implant survival rate was 83.8% (95% CI 76.7 to 88.9). Multivariable analysis identified three predictors of re-revision: multiple revision indications (hazard ratio (HR) = 2.78; 95% CI 1.03 to 7.49; p = 0.043); selective component revisions (HR = 5.76; 95% CI 1.28 to 25.9; p = 0.022); and ceramic-on-polyethylene revision bearings (HR = 3.08; 95% CI 1.01 to 9.36; p = 0.047).Non-MoMHAs revised for ARMD have a high short-term risk of re-revision, with important predictors of future re-revision including selective component revision, multiple revision indications, and ceramic-on-polyethylene revision bearings. Our findings may help counsel patients about the risks of ARMD revision, and guide reconstructive decisions. Future studies attempting to validate the predictors identified should also assess the effects of implant design (metallurgy and modularity), given that this was an important study limitation potentially influencing the reported prognostic factors.Cite this article: G. S. Matharu, A. Judge, D. W. Murray, H. G. Pandit. Outcomes following revision surgery performed for adverse reactions to metal debris in non-metal-on-metal hip arthroplasty patients: Analysis of 185 revisions from the National Joint Registry for England and Wales. Bone Joint Res 2017;6:405-413. DOI: 10.1302/2046-3758.67.BJR-2017-0017.R2
Laterally unrestrained bearing strength of hot-wet conditioned pultruded FRP material
No full textPresented in this paper are test results of a study pertaining to the reduction in bearing strength due to the effect of hot-wet conditioning on specimens cut from a polyester matrix based pultruded FRP structural shape. A total of 100 coupons (for 20 batches of five) were immersed in distilled water for three and six months at a constant temperature of 40°C. Subsequently, they were load tested using stainless steel ‘pins’ of M10 and M20 sizes with material orientations of 0o, 45o and 90o
to the direction of pultrusion. Furthermore, this test series considered the effect of loading with and without bolt thread in the bearing zone. Testing employed a non-standard set-up that accommodates smaller test coupons, allowing material to be sourced from the web
and flange of a 254×254×9.53 mm wide flange shape. An evaluation of the salient results provides characteristic bearing strength values (in accordance with Annex D of EN1990) and comparisons are drawn between equivalent strengths for non-aged (zero months) material from a previous test series. The degree of strength reduction is found to be influenced by both the ‘pin’ size and type, and observations are drawn towards the safe and reliable design of bolted connections
Revision surgery of metal-on-metal hip arthroplasties for adverse reactions to metal debris
No full textBackground and purpose — The initial outcomes following metal-on-metal hip arthroplasty (MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD) were poor. Furthermore, robust thresholds for performing ARMD revision are lacking. This article is the second of 2. The first article considered the various investigative modalities used during MoMHA patient surveillance (Matharu et al. 2018a). The present article aims to provide a clinical update regarding ARMD revision surgery in MoMHA patients (hip resurfacing and large-diameter MoM total hip arthroplasty), with specific focus on the threshold for performing ARMD revision, the surgical strategy, and the outcomes following revision. Results and interpretation — The outcomes following ARMD revision surgery appear to have improved with time for several reasons, among them the introduction of regular patient surveillance and lowering of the threshold for performing revision. Furthermore, registry data suggest that outcomes following ARMD revision are influenced by modifiable factors (type of revision procedure and bearing surface implanted), meaning surgeons could potentially reduce failure rates. However, additional large multi-center studies are needed to develop robust thresholds for performing ARMD revision surgery, which will guide surgeons’ treatment of MoMHA patients. The long-term systemic effects of metal ion exposure in patients with these implants must also be investigated, which will help establish whether there are any systemic reasons to recommend revision of MoMHAs</p
What is appropriate surveillance for metal-on-metal hip arthroplasty patients?
No full textThe unexpected high revision rates of large-diameter (femoral head sizes of 36 mm or greater) metal-on-metal hip arthroplasties (MoMHAs) have led to worldwide regulatory authorities recommending regular surveillance, even for asymptomatic individuals. However, these recommendations are not evidence-based and are very costly. The rapidly evolving evidence base requires an update regarding the investigation and management of MoMHA patients. This article is the first of 2 (the second article in this series will consider the threshold for performing revision, and the outcomes following ARMD revision surgery: Matharu et al., Revision surgery of metal-on-metal hip arthroplasties for adverse reactions to metal debris: A clinical update. Acta Orthop 2018; in press), and considers the various investigative modalities used during surveillance, with specific focus on blood metal ion sampling and cross-sectional imaging. No single investigation can universally be used during MoMHA patient surveillance. Recent studies have now provided important information on interpreting blood metal ions (effective in identifying patients at low risk of problems), clarifying the roles of cross-sectional imaging (reserve combined ultrasound and MARS-MRI for complex cases), and providing parameters to safely exclude many asymptomatic patients from regular surveillance. This information will be useful when designing future surveillance protocols for MoMHA patients
Highly Efficient Mesoporous Carbonaceous CeO2Catalyst for Dephosphorylation
No full textPhosphorus is fast becoming a critical element, as the global supply and demand are reaching unsustainable levels. Herein, the synthesis, characterization, and applicability of a novel biomass-derived mesoporous carbonaceous material decorated with CeO2 (CeO2-S400) as an efficient catalyst for the dephosphorylation of 4-nitrophenyl phosphate disodium salt hexahydrate are reported. The presence and distribution of CeO2 are evidenced by inductively coupled plasma mass spectrometry (ICP-MS) (118.7 mg/g), high-resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray (EDX) mapping. The apparent rate constant for the efficient catalysis of 4-nitrophenyl phosphate disodium salt hexahydrate was 0.097 ± 0.01 for CeO2-ES and 0.15 ± 0.03 min-1 for CeO2-S400, which followed first-order kinetics. Rate constants normalized by the catalytic loading (km) were 80.84 and 15.00 g-1 min-1 for CeO2-ES and CeO2-S400, respectively, and the normalized rate constants with respect to surface area were 3.38 and 0.04 m-2 min-1 for CeO2-ES and CeO2-S400, respectively. This indicates that the presence of CeO2 nanoparticles has a catalytic effect on the dephosphorylation reaction
Design of highly active Ni catalysts supported on carbon nanofibers for the hydrolytic hydrogenation of cellobiose
No full text1 scheme, 7 figures, 2 tables.The direct transformation of cellulose into sugar alcohols (one-pot conversion) over supported nickel catalysts represents an attractive chemical route for biomass valorization, allowing the use of subcritical water in the hydrolysis step. The effectiveness of this process is substantially conditioned by the hydrogenation ability of the catalyst, determined by design parameters such as the active phase loading and particle size. Herein, mechanistic insights into catalyst design to produce superior activity were outlined using the hydrolytic hydrogenation of cellobiose as a model reaction. Variations in the impregnation technique (precipitation in basic media, incipient wetness impregnation, and the use of colloidal-deposition approaches) endowed carbon-nanofiber-supported catalysts within a wide range of Ni crystal sizes (5.8–20.4 nm) and loadings (5–14 wt%). The link between the properties of these catalysts and their reactivity has been established using characterization techniques such as X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma-optical emission spectroscopy (ICP-OES). A fair compromise was found between the Ni surface area (3.89 m2/g) and its resistance against oxidation for intermediate crystallite sizes (∼11.3 nm) loaded at 10.7 wt%, affording the hydrogenation of 81.2% cellobiose to sorbitol after 3 h reaction at 190°C and 4.0 MPa H2 (measured at room temperature). The facile oxidation of smaller Ni particle sizes impeded the use of highly dispersed catalysts to reduce the metal content requirements.The authors are grateful for the financial support from the Spanish Ministry of Economy and Competitiveness (MINECO, Project ENE2017-83854-R) and the I + D + © project PID 2020-115053RB-I00, funded by MCIN/AEI/10.13039/501100011033. JR is grateful to the Spanish Ministry of Science, Innovation and Universities for the Juan de la Cierva Incorporación (JdC-I) fellowship (Grant Number: IJC 2018-037110-I) awarded.Peer reviewe
Correction to: European headache federation guideline on the use of monoclonal antibodies acting on the calcitonin gene related peptide or its receptor for migraine prevention (Journal of Headache and Pain (2019) 20:6 DOI: 10.1186/s10194-018-0955-y)
No full textFollowing publication of the original article [1], the authors notified us of some misreported data due to the publication of the EVOLVE-2 trial (Cephalalgia. 2018;38:1442-1454), which substantially changed the level of evidence of galcanezumab for the prevention of episodic migraine. All changes are marked in bold and with red in Figure 1 and Figure 2. Please note that the final recommendations remain unchanged. Reference #51 was added: Skljarevski V, Matharu M, Millen BA, Ossipov MH, Kim B-K, Yang JY. Efficacy and safety of galcanezumab for the prevention of episodic migraine: Results of the EVOLVE-2 Phase 3 randomized controlled clinical trial. Cephalalgia. 2018;38:1442-1454. Please find below the updated text, tables, and figures. Results We identified 29 studies eligible to be considered in the present guidelines (Fig. 1) [23-51]. Fifteen of the selected studies (Tables 1 and 2) were phase II or III randomized clinical trials (RCTs) reporting data on safety or efficacy of the CGRP mAbs [26,27,31-36,41-45,50,51]; 14 additional studies were post-hoc or pooled analyses from the RCTs, open label-extension of the RCTs, or open label studies [23-25,28-30,37-40,46-49]. Risk of bias summary for the selected studies is reported in Fig. 2. Certainty assessment of outcomes for studies in EM and CM is reported in Tables 3 and 4. Recommendations related to the use of CGRP mAbs for prevention of EM and CM are reported in Table 5. PICO question 1: In patients with EM, is preventive treatment with CGRP mAbs as compared to placebo, effective and safe? Population: patients with EM Intervention: any preventive CGRP mAb Comparison: placebo Outcome: reduction in days of migraine or headache, reduction in the use of acute attack medication, improvement in function, responder ratio (patients with > 50% reduction in migraine or headache days), serious adverse events (SAEs), mortality (grade of importance: critical) Analysis of evidence We found 15 eligible studies which evaluated whether treatment with CGRP mAbs as compared to placebo is effective and safe [26,27,31-36,41-45,50,51]. Among the eligible studies one was on eptinezumab [32], five studies on erenumab [35,36,44,45,50], four studies on fremanezumab [26,27,34,41], and five studies on galcanezumab [31,33,42,43]. One phase IIIb study on erenumab was not included in the PICO question 1 because it included only patients with previous drug failure [50]. Eptinezumab Summary of findings for treatment with eptinezumab quarterly injection compared with placebo for prevention of EM is provided in Table 6. (Figure presented)
The Hy-MASS concept:Hydrothermal microwave assisted selective scissoring of cellulose for: In situ production of (meso)porous nanocellulose fibrils and crystals
No full textThe hydrothermal microwave-assisted selective scissoring (Hy-MASS) of depectinated orange peel residues (OPR), produced via conventional acid hydrolysis and acid-free microwave processing, to yield (meso)porous nanocellulose fibrils and crystals simultaneously in the absence of additional auxiliary reagents and/or mechanical treatment is reported. In the stepwise microwave hydrothermal treatment (MHT) of OPR from 120 °C-200 °C at 20 °C intervals, release of residual pectins and hemicelluloses is observed up to 180 °C producing nanocellulose fibrils (3-15 × 500-2000 nm). Beyond 180 °C, selective leaching/hydrolysis of amorphous regions occur to yield nanocellulose crystals (200-400 × 40-50 nm) and crystallites (5-15 × 40-50 nm). This selective, step-wise scissoring process is termed Hy-MASS Concept. Structure, morphology and properties of (meso)porous nanocellulose are strongly influenced by pectin extraction methodology employed. With acid depectinated OPR, deconstruction of the lignocellulosic matrix via microwave is hastened by approx. 20 °C with respect to acid-free microwave depectinated OPR. Td of acid depectinated nanocelluloses (CMC) is ca. 350 °C compared to microwave depectinated nanocelluloses (MMC, Td, varies 342-361 °C). Nanocellulose produced via microwave pre-treatment is (meso)porous: BJH pore size 5-35 nm; BET surface area, 1.5-107 m2 g-1, and; BJH pore volume, 0.01-0.27 cm3 g-1, when compared to acid pre-treated counterparts. The crystallinity index of CMC and MMC increases in two stages, 120-140 °C (ca. 8%) and at 180-200 °C (5-9%). XRD revealed presence of calciuim salts, most likely calcium oxalate. The hydration capacities of nanocelluloses (12-23 g water per g sample) are much higher than their precursors or literature citrus nanocellulose
- …
