127 research outputs found
Current status and future perspectives of lithium metal batteries
With the lithium-ion technology approaching its intrinsic limit with graphite-based anodes, Li metal is recently receiving renewed interest from the battery community as potential high capacity anode for next-generation rechargeable batteries. In this focus paper, we review the main advances in this field since the first attempts in the mid-1970s. Strategies for enabling reversible cycling and avoiding dendrite growth are thoroughly discussed, including specific applications in all-solid-state (inorganic and polymeric), Lithium–Sulfur (Li–S) and Lithium-O2 (air) batteries. A particular attention is paid to recent developments of these battery technologies and their current state with respect to the 2030 targets of the EU Integrated Strategic Energy Technology Plan (SET-Plan) Action 7
Uncemented and cemented primary total hip arthroplasty in the Swedish Hip Arthroplasty Register: Evaluation of 170,413 operations
BACKGROUND AND PURPOSE: Since the introduction of total hip arthroplasty (THA) in Sweden, both components have most commonly been cemented. A decade ago the frequency of uncemented fixation started to increase, and this change in practice has continued. We therefore analyzed implant survival of cemented and uncemented THA, and whether the modes of failure differ between the two methods of fixation. PATIENTS AND METHODS: All patients registered in the Swedish Hip Arthroplasty Register between 1992 and 2007 who received either totally cemented or totally uncemented THA were identified (n = 170,413). Kaplan-Meier survival analysis with revision of any component, and for any reason, as the endpoints was performed. Cox regression models were used to calculate risk ratios (RRs) for revision for various reasons, adjusted for sex, age, and primary diagnosis. RESULTS: Revision-free 10-year survival of uncemented THA was lower than that of cemented THA (85% vs. 94%, p < 0.001). No age or diagnosis groups benefited from the use of uncemented fixation. Cox regression analysis confirmed that uncemented THA had a higher risk of revision for any reason (RR = 1.5, 95% CI: 1.4-1.6) and for aseptic loosening (RR = 1.5, CI: 1.3-1.6). Uncemented cup components had a higher risk of cup revision due to aseptic loosening (RR = 1.8, CI: 1.6-2.0), whereas uncemented stem components had a lower risk of stem revision due to aseptic loosening (RR = 0.4, CI: 0.3-0.5) when compared to cemented components. Uncemented stems were more frequently revised due to periprosthetic fracture during the first 2 postoperative years than cemented stems (RR = 8, CI: 5-14). The 5 most common uncemented cups had no increased risk of revision for any reason when compared with the 5 most commonly used cemented cups (RR = 0.9, CI: 0.6-1.1). There was no significant difference in the risk of revision due to infection between cemented and uncemented THA. INTERPRETATION: Survival of uncemented THA is inferior to that of cemented THA, and this appears to be mainly related to poorer performance of uncemented cups. Uncemented stems perform better than cemented stems; however, unrecognized intraoperative femoral fractures may be an important reason for early failure of uncemented stems. The risk of revision of the most common uncemented cup designs is similar to that of cemented cups, indicating that some of the problems with uncemented cup fixation may have been solved.Open Access - This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited
Total hip replacement. Results of a postal survey of current practice on the cement fixation of the acetabular cup in the UK
Previous finite element studies and laboratory investigations on reconstructed acetabulum joints show that long-term fixation of the acetabular cup in total hip replacements (THRs) is influenced by surgical fixation techniques. The aim of this study is to determine and understand the reasons of current practice in the cement fixation of the acetabular cup in THRs in the UK. Following a pilot study, a postal survey was carried out among 1350 orthopaedic consultants. Response rate was 40% and data obtained from the returned questionnaires provided information about the current practice of 431 consultants with an average of 16.5 years of experience and who perform an average of 55 cemented THR operations annually. The survey showed wide variations in the fixation methods of the acetabular component. 95% of the respondents use cement to fix the acetabular cup, 46% maintain the subchondral bone and 63 % use a flanged acetabular cup. The numbers of anchorage holes drilled vary from zero to thirty-six and drill diameters vary from 2 to 15 mm. Anchorage hole depths vary from 3 to 20 mm. Given the variability of surgical fixation methods, further studies need to be carried out to determine how fixation techniques could be improved to increase the longevity of the acetabular component in THRs. Further investigations could lead to a better understanding of the factors that contribute to the stability of THRs
Measurement of migration of a humeral head resurfacing prosthesis using radiostereometry without implant marking: An experimental study
Today, the shoulder joint is the third most commonly replaced joint after the hip and knee joints and the incidence is increasing. In Sweden, 1863 primary Shoulder Arthroplasties and 195 revisions were performed in 2017. The most common diagnoses are Osteoarthritis and irreparable tears of the rotator cuff, with or without arthropathy, often referred to as cuff tear arthropathy.
Different Shoulder Arthroplasty (SA) concepts include anatomical total shoulder arthroplasty (TSA), hemiarthroplasty (HSA) and reversed shoulder arthroplasty, but also humeral head resurfacing (HHR) and stemless arthroplasties. All concepts offer pain relief, improvement of function and in quality of life for the different diagnoses. Unfortunately, there are sometimes complications after SA. They involve periprosthetic joint infection, humeral and glenoid fractures, stress shielding, loosening of the glenoid and humeral component but also glenoid erosion and cuff rupture. Some of these complications are most common within 1 year after operation, some after several years, both may lead to a revision. This, together with the fact that new designs of implants and methods of fixation of SA continues to develop, stresses the importance of continuous monitoring of implant survival and follow-up.
The overall aim of this thesis was to describe clinical examples of different methods to assess the outcome after Shoulder Arthroplasty. The most common methods are clinical examination, radiographic assessment, Patient Reported Outcome Measure (PROM), National Joint registries, where revisions are an important outcome, but also Clinical Trials. All of these methods are used in one or more of the 4 papers in this thesis and shows the complexity of the topic and the practical work.
In paper I we used Radio Stereometric Analysis (RSA) in an experimental set-up and concluded that marker-free RSA can be used for a humeral head resurfacing arthroplasty. In paper II we used data from the Swedish Shoulder Arthroplasty Registry (SSAR) with PROM and revisions to conclude that age is the only factor that affects revision when comparing HSA and HHR. Paper III is a long-time follow-up of a Randomized controlled study where we used radiological assessment, PROM and revisions. The conclusion was that both TSA and HSA develop severe radiological changes 10 year after primary operation. Paper IV is a prospective RSA cohort study where we also evaluated PROM and revisions. The conclusion is that HHR seems to obtain a secure fixation in the humerus, after an initial migration. But also that the prostheses shows continuous glenoid wear.
The main conclusion of this thesis is that patient’s operated with SA needs continuous monitoring and several methods may be used to evaluate the outcome
Comparison of trabecular metal cups and titanium fiber-mesh cups in primary hip arthroplasty: A randomized RSA and bone mineral densitometry study of 50 hips
Using plant wax markers to estimate the diet composition of grazing Holstein dairy cows
The objective of this study was to test whether diet selection of dairy cows under grazing conditions could be estimated using plant wax markers. Furthermore, differences between 2 cow strains and the effect of concentrate supplementation on plant species selection were investigated. The experiment was a study with a crossover design performed on an organic farm with 12 Swiss Holstein cows and 12 New Zealand Holstein cows. Both experimental periods consisted of a 21-d adaptation and a 7-d measurement period. All cows grazed full time in a rotational stocking system and received either no concentrate or 6 kg/d of a commercial cereal-grain mix. Representative herbage samples of each grazed paddock were taken and botanical composition of subsamples was manually determined. The average proportions of the plant species were 27.8% Lolium perenne, 6.1% Dactylis glomerata, 10.4% Trifolium repens, and 9.0% Taraxacum officinale. Other grass species were merged as "other grass" (38.2%) and other forb species as "other forbs" (8.5%). n-Alkanes, long-chain fatty acids, and long-chain alcohols (LCOH) were analyzed in the samples of plant species, concentrate, and feces from each cow. A linear discriminant analysis indicated that diet components were differentiated best with LCOH (96%) and worst with the combination of all marker groups together (12%). For each marker, the fecal marker recovery (FR) relative to dosed ytterbium was determined in 2 ways. Estimation of diet composition was performed with the software "EatWhat," and results were compared with botanical composition with the Aitchison distance. The results indicate that the diet composition of grazing dairy cows can be estimated using plant wax markers. Additionally, the calculation of FR led to mostly reliable results, yet this approach needs further validation. The most accurate estimation was achieved with the marker combination of n-alkanes and LCOH with a correction for FR. Less accurate estimations were achieved with long-chain fatty acids alone or in combination with n-alkanes. No difference relating to diet selection between the 2 cow strains was recorded, but supplemented cows apparently ingested higher proportions of T. repens than nonsupplemented cows. Awareness that supplementation influences selection behavior of grazing dairy cows may lead to adaptations in botanical composition of the pasture according to the demand of the animals
Upregulated HSP27 in human breast cancer cells reduces Herceptin susceptibility by increasing Her2 protein stability
<p>Abstract</p> <p>Background</p> <p>Elucidating the molecular mechanisms by which tumors become resistant to Herceptin is critical for the treatment of Her2-overexpressed metastatic breast cancer.</p> <p>Methods</p> <p>To further understand Herceptin resistance mechanisms at the molecular level, we used comparative proteome approaches to analyze two human breast cancer cell lines; Her2-positive SK-BR-3 cells and its Herceptin-resistant SK-BR-3 (SK-BR-3 HR) cells.</p> <p>Results</p> <p>Heat-shock protein 27 (HSP27) expression was shown to be upregulated in SK-BR-3 HR cells. Suppression of HSP27 by specific siRNA transfection increased the susceptibility of SK-BR-3 HR cells to Herceptin. In the presence of Herceptin, Her2 was downregulated in both cell lines. However, Her2 expression was reduced by a greater amount in SK-BR-3 parent cells than in SK-BR-3 HR cells. Interestingly, co-immunoprecipitation analysis showed that HSP27 can bind to Her2. In the absence of Herceptin, HSP27 expression is suppressed and Her2 expression is reduced, indicating that downregulation of Her2 by Herceptin can be obstructed by the formation of a Her2-HSP27 complex.</p> <p>Conclusion</p> <p>Our present study demonstrates that upregulated HSP27 in human breast cancer cells can reduce Herceptin susceptibility by increasing Her2 protein stability.</p
Employment Services Utilization and Outcomes among Substance Abusing Offenders Participating in California’s Proposition 36 Drug Treatment Initiative
California drug treatment programs may use funds to address barriers to work faced by Proposition 36 offenders, most of whom are not working at treatment entry, but employment services utilization and related behavioral outcomes have never been studied. This study examined primary data collected on 1,453 offenders by 30 programs during 2004 to explore the characteristics, employment services utilization, and outcomes of those who did and did not receive employment services while in drug treatment. One-year outcomes were mostly similar across groups, however, increases in the proportion of offenders employed, receiving income from employment and family or friends, and being paid for work were significantly greater among the received-employment-services group, and a greater proportion of this group also completed drug treatment. Employment services utilization was less likely for persons recruited from outpatient settings and more likely with greater severity of family/social problems and desire for services. Odds of employment one-year post-treatment entry were higher for those of Hispanic race/ethnicity (vs. White) and for those with treatment completion/longer retention but lower for those who were older, lived in specific counties, had greater employment problem severity at intake, and received other income-related services. Strategies for improving employment services utilization and outcomes among Proposition 36 offenders are discussed
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