Sporttherapie bei Coxarthrose : Eine randomisierte kontrollierte Studie

BACKGROUND: Roughly one in ten persons in the industrialized world suffers from hip osteoarthritis, a disease for which there is no cure. The goal of conservative therapy is to relieve symptoms, preferably with methods that let patients assume responsibility for their own treatment, e.g., physical training. METHODS: In a randomized controlled trial, we studied the effectiveness of twelve weeks of exercise therapy in patients with hip osteoarthritis (THüKo), compared to no treatment (control group) and placebo ultrasound treatment of the hip (placebo ultrasound group). The primary endpoint was a comparison of the pain scores of the intervention versus control groups on the generic SF-36 health questionnaire. Secondary endpoints included comparisons across all three study groups of scores on the 7 other scales of the SF-36 and on the pain, physical function, and stiffness scales of the osteoarthritis-specific WOMAC Index. The statistical analysis was performed with ANCOVA, with baseline values as a covariate. Between-group effects were subsequently tested pairwise (two-tailed t-tests, alpha = 0.05). RESULTS: As for the primary endpoint, pain reduction was significantly greater in the intervention than in the control group (mean difference 5.7 points, 95% confidence interval [CI] 0.4–11.1 points, p = 0.034). The comparisons across all three study groups (i.e., secondary endpoints, with 71 subjects in the intervention group, 68 in the control group, and 70 in the placebo group) revealed no significant between-group effects with respect to the SF-36. On the WOMAC Index, however, statistically significant differences were found for pain reduction between the intervention and control group (mean difference 7.4 points, 95% CI 3.0–11.8, p = 0.001) and between the intervention and placebo group (mean difference 5.1 points, 95% CI 0.7–9.4, p = 0.024). Comparable mean differences were also found for functional improvement. CONCLUSION: Twelve weeks of exercise therapy in hip osteoarthritis patients of normal vitality reduced pain and improved physical function. No significant improvement was found in these patients‘ general health-related quality of life

Conventional Electrolyte and Inactive Electrode Materials in Lithium Ion Batteries: Determining Cumulative Impact of Oxidative Decomposition at high voltage

High‐voltage electrodes based on, for example, LiNi0.5Mn1.504 (LNMO) active material require oxidative stability of inactive materials up to 4.95 V vs. Li|Li+. Referring to literature, they are frequently supposed to be unstable, though conclusions are still controversial and clearly depend on the used investigation method. For example, the galvanostatic method, as a common method in battery research, points to the opposite, thus to a stability of the inactive materials, which can be derived from, for example, the high decomposition plateau at 5.56 V vs. Li|Li+ and stable performance of the LNMO charge/discharge cycling. This work aims to unravel this apparent contradiction of the galvanostatic method with the literature by a thorough investigation of possible trace oxidation reactions in cumulative manner, that is, over many charge/discharge cycles. Indeed, the cumulated irreversible specific capacity amounts to ≈10 mAh g−1 during the initial 50 charge/discharge cycles, which is determined by imitating extreme LNMO high‐voltage conditions using electrodes solely consisting of inactive materials. This can explain the ambiguities in stability interpretations of the galvanostatic method and the literature, as the respective irreversible specific capacity is obviously too low for distinct detection in conventional galvanostatic approaches and can be only detected at extreme high‐voltage conditions. In this regard, the technique of chronoamperometry is shown to be an effective and proper complementary tool for electrochemical stability research in a qualitative and quantitative manner

Influence of LiPF 6 on the Aluminum Current Collector Dissolution in High Voltage Lithium Ion Batteries after Long-Term Charge/Discharge Experiments

The long-term influence of the most commonly used conducting salt in electrolyte formulations, lithium hexafluorophosphate, on the aluminum current collector stability in high voltage lithium ion batteries was investigated. By means of different surface sensitive techniques (scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy), after 1003 simulated charge/discharge cycles, anodic aluminum dissolution was found to take place at elevated potential (4.95 V vs. Li/Li+) but only to a minor extent. Pitting of the Al collector could be assessed in the nanometer range. Furthermore, it could be revealed that local pit formation is related to local "native" grooves on the aluminum foil, which develop during the production process of the aluminum foil. The obtained results were evaluated and compared to a reference electrolyte containing the alternative conducting salt lithium bis(trifluoromethanesulfonyl)imide. Our findings imply two possible mechanisms for the occurring Al dissolution behavior at elevated potentials. Either, an accelerated aluminum dissolution process, or a continuous passivation/LiPF6-decomposition process

Evaluation of Allylboronic Acid Pinacol Ester as Effective Shutdown Overcharge Additive for Lithium Ion Cells

Allylboronic acid pinacol ester (ABPE) was investigated as shutdown overcharge additive to increase the intrinsic safety of lithium ion cells during operation at elevated charge cutoff potentials up to 4.5 V vs. Li/Li+. It was demonstrated that the additive had no negative influence on the cycling performance of LiNi1/3Co1/3Mn1/3O2 (NMC-111)/graphite full cells operated in a standard operation voltage range between 2.5 V and 4.2 V. Electrochemical impedance spectroscopy was used to study the influence of the electrolyte additive on the impedance before and after overcharge and concomitant cell shutdown. Thereby, an immense increase in the charge transfer resistance after electrode shutdown was observed, thus, hinting to the formation of a lithium ion-insulating layer on the positive electrode surface. To further elucidate the working principle of the shutdown additive, surface investigations by means of scanning electron microscopy and X-ray photoelectron spectroscopy were carried out. The existence of a surface layer consisting mainly of polymeric species was proven. The presented results open up a new family of compounds for overcharge protectio