Purpose To evaluate the biomechanical and design characteristics of all-suture anchors. Methods All-suture anchors were tested in fresh porcine cortical bone and biphasic polyurethane foam blocks by ...cyclic loading (10-100 N for 200 cycles), followed by destructive testing parallel to the insertion axis at 12.5 mm/s. Endpoints included ultimate failure load, displacement at 100 and 200 cycles, stiffness, and failure mode. Anchors tested included JuggerKnot (1.4, 1.5, and 2.8), Iconix (1, 2, and 3), Y-knot (1.3, 1.8, and 2.8), Q-Fix (1.8 and 2.8), and Draw Tight (1.8 and 3.2). Results The mean ultimate failure strength of the triple-loaded anchors (564 ± 42 N) was significantly greater than the mean ultimate failure strength of the double-loaded anchors (465 ± 33 N) ( P = .017), and the double-loaded anchors were stronger than the single-loaded anchors (256 ± 35 N) ( P < .0001). No difference was found between the results in porcine bone and biphasic polyurethane foam. None of these anchors demonstrated 5 mm or 10 mm of displacement during cyclic loading. The Y-Knot demonstrated greater displacement than the JuggerKnot and Q-Fix ( P = .025) but not the Iconix and Draw Tight ( P > .05). The most common failure mode varied and was suture breaking for the Q-Fix (97%), JuggerKnot (81%), and Iconix anchors (58%), anchor pullout with the Draw Tight (76%), whereas the Y-Knot was 50% suture breaking and 50% anchor pullout. Conclusions The ultimate failure load of an all-suture anchor is correlated directly with its number of sutures. With cyclic loading, the Y-Knot demonstrated greater displacement than the JuggerKnot and Q-Fix but not the Iconix and Draw Tight. JuggerKnot (81%) and Q-Fix (97%) anchors failed by suture breaking, whereas the Draw Tight anchor failed by anchor pullout (76%). Clinical Relevance All-suture anchors vary in strength and performance, and these factors may influence clinical success. Biphasic polyurethane foam is a validated model for suture anchor testing.
Spin-transfer torque and spin Hall effects combined with their reciprocal phenomena, spin pumping and inverse spin Hall effects (ISHEs), enable the reading and control of magnetic moments in ...spintronics. The direct observation of these effects remains elusive in antiferromagnetic-based devices. We report subterahertz spin pumping at the interface of the uniaxial insulating antiferromagnet manganese difluoride and platinum. The measured ISHE voltage arising from spin-charge conversion in the platinum layer depends on the chirality of the dynamical modes of the antiferromagnet, which is selectively excited and modulated by the handedness of the circularly polarized subterahertz irradiation. Our results open the door to the controlled generation of coherent, pure spin currents at terahertz frequencies.
Purpose The purpose of this study was to evaluate the biomechanical and design characteristics of newer suture anchors under cyclic loading. Methods Suture anchors were tested in fresh porcine ...cortical and cancellous bone by cyclic loading (10 to 100 N for 200 cycles) followed by destructive testing parallel to the insertion axis at 12.5 mm per second. End points included ultimate failure load, displacement at 100 and 200 cycles, failure mode, and stiffness. Anchors tested included ReelX (Stryker Endoscopy, San Jose, CA); Footprint Ultra PK (4.5 and 5.5 mm) (Smith & Nephew, Andover, MA); TwinFix (4.5, 5.5, and 6.5 mm made from polyether ether ketone PEEK, hydroxyapatite HA, and titanium Ti) (Smith & Nephew Endoscopy, Andover, MA); Morphix (2.5 and 5.5 mm) (MedShape Solutions, Atlanta, GA); CrossFT BC (ConMed-Linvatec, Largo, FL); JuggerKnot (1.5 and 2.8 mm) (Biomet Sports Medicine, Warsaw, IN); Healicoil (Smith & Nephew Endoscopy, Andover, MA); Quattro (X, Link, and GL) (Cayenne Medical, Scottsdale, AZ); Healix (Biocryl Rapide BR, PEEK, and Ti) (DePuy Mitek, Raynham, MA); Twin Loop (3.5 mm, PEEK) (Stryker Endoscopy, San Jose, CA); PressFT (2.1 and 2.6 mm) (ConMed Linvatec, Largo FL); Y-Knot (ConMed Linvatec, Largo FL); Gryphon (BR and PEEK) (DePuy Mitek, Raynham, MA); and Iconix (1, 2, and 3) (Stryker Endoscopy, San Jose, CA). Results Rotator cuff anchors showed greater failure loads than did glenoid anchors in metaphyseal bone (rotator cuff anchors 448 N v glenoid anchors 296 N) ( P = .001) and cancellous bone (rotator cuff anchors 435 N v glenoid anchors 225 N) ( P < .001). No anchors reached 5 mm of displacement during cyclic loading. TwinFix anchors showed greater displacement at 100 ( P = .014) and 200 cycles ( P = .036) than did other rotator cuff anchors, although the ReelX and Morphix showed the greatest displacements. Rotator cuff anchors failed principally by eyelet breaking, whereas glenoid anchors failed more often by anchor pullout than by any other mode. No differences in stiffness were observed across the different rotator cuff and glenoid anchors tested. Conclusions Rotator cuff anchors showed higher failure strengths than did glenoid anchors, regardless of bone type. TwinFix anchors showed more cyclic displacement than did other rotator cuff anchors (except the ReelX and Morphix anchors) and the glenoid anchors tested. The failure mode was dependent on the specific anchor. Clinical Relevance Suture anchor constructs tested showed that failure load is dependent on anchor type (rotator cuff anchor or glenoid anchor) but not on anchor location (cancellous or cortical bone).
Animal physiology, ecology and evolution are affected by temperature and it is expected that community structure will be strongly influenced by global warming. This is particularly relevant in the ...tropics, where organisms are already living close to their upper temperature limits and hence are highly vulnerable to rising temperature. Here we present data on upper temperature limits of 34 tropical marine ectotherm species from seven phyla living in intertidal and subtidal habitats. Short term thermal tolerances and vertical distributions were correlated, i.e., upper shore animals have higher thermal tolerance than lower shore and subtidal animals; however, animals, despite their respective tidal height, were susceptible to the same temperature in the long term. When temperatures were raised by 1°C hour(-1), the upper lethal temperature range of intertidal ectotherms was 41-52°C, but this range was narrower and reduced to 37-41°C in subtidal animals. The rate of temperature change, however, affected intertidal and subtidal animals differently. In chronic heating experiments when temperature was raised weekly or monthly instead of every hour, upper temperature limits of subtidal species decreased from 40°C to 35.4°C, while the decrease was more than 10°C in high shore organisms. Hence in the long term, activity and survival of tropical marine organisms could be compromised just 2-3°C above present seawater temperatures. Differences between animals from environments that experience different levels of temperature variability suggest that the physiological mechanisms underlying thermal sensitivity may vary at different rates of warming.
Objective Risk algorithms were used to identify a high-risk population for transcatheter aortic valve implantation instead of standard aortic valve replacement in patients with aortic stenosis. We ...evaluated the efficacy of these methods for predicting outcomes in high-risk patients undergoing aortic valve replacement. Methods Data were collected on 638 patients identified as having isolated aortic valve replacement between January 1, 1998 and December 31, 2006, using The Society of Thoracic Surgeons (STS) database. Long-term survival was determined from the Social Security Death Index or family contact. Operative risk was calculated using the STS Predicted Risk of Mortality, the EuroSCORE logistic and additive algorithms, and the Ambler Risk Score. Patients at or above the 90th percentile of risk (8.38% for STS, 33.47% for logistic, 12% for additive, 14.3% for Ambler) were identified as high risk. We then compared actual with predicted mortality and each algorithm’s ability to identify patients with the worst long-term survival. Results Operative mortality was 24 of 638 (3.76%). An additional 121 (19.0%) patients died during the follow-up study period (mean 4.2 ± 2.7 years). Overall mortality was 145 of 638 (22.7%). Expected versus observed mortality for the high-risk group by algorithm was 13.3% versus 18.8% for STS, 50.9% versus 15.6% for logistic, 14.0% versus 11.9% for additive, and 19.0% versus 13.4% by Ambler. Long-term mortality, per high-risk group, was 64.1% in the STS Predicted Risk of Mortality, 45.3% in the logistic, 45.2% in the additive, and 40.2% in Ambler Risk Score. Logistic regression showed that the STS algorithm was the most sensitive in defining the patients most at risk for long-term mortality. Conclusion The STS Predicted Risk of Mortality most accurately predicted perioperative and long-term mortality for the highest risk patients having aortic valve replacement.
Intermediate- and high-risk patients undergoing isolated surgical aortic valve replacement have superior outcomes at higher-volume compared with lower-volume hospitals. This study examines the impact ...of hospital volume on outcomes in low-risk patients undergoing aortic valve replacement.
Using data from our 29 North Texas hospital collaborative, we examined 2066 low-risk cases (Society of Thoracic Surgeons Predicted Risk of Mortality of ≤3%) undergoing aortic valve replacement surgery between January 1, 2012, and December 31, 2017. Cases from 3 high-volume hospitals (≥200 aortic valve replacement cases total) and 26 low-volume hospitals (<200 cases total) were examined.
Some 53.5% of the cases were at high-volume hospitals. No statistical differences were seen in the Predicted Risk of Mortality or pertinent demographics between the high-volume and low-volume hospitals. Significant differences in outcomes were seen between the 2 groups in operative mortality (2.28% vs 1.19%, P = .007), renal failure (2.14% vs 1.00%, P = .003), and readmission within 30 days (9.72% vs 6.25%, P < .001) when comparing low-volume with high-volume hospitals. In patients undergoing aortic valve replacement, undergoing the procedure in a low-volume hospital was an independent predictor for operative mortality (odds ratio, 1.95; 95% confidence interval, 1.20-3.20; P = .008) and renal failure (odds ratio, 2.25; 95% confidence interval, 1.33-3.81; P = .003).
Operative mortality in low-risk patients undergoing aortic valve replacement is higher in low-volume compared with high-volume hospitals. The probability of a major complication, such as renal failure, is also greater in low-volume hospitals. The relationship between volume and outcomes in low-risk patients will require more research to understand the causes and design appropriate interventions.
Previous coronary artery bypass grafting increases predicted operative risk for conventional valve replacement, according to the Society of Thoracic Surgeons risk algorithm. Additionally, the ...presence of coronary artery disease (CAD) has been demonstrated to increase procedural risk with conventional aortic valve replacement. Significant coexisting CAD requires preemptive percutaneous coronary intervention (PCI) in patients under consideration for transcatheter aortic valve implantation (TAVI). This study examined the impact of previous coronary artery bypass grafting or PCI on procedural outcomes and overall survival in patients having TAVI.
Two hundred and one high-risk patients were enrolled in two international feasibility studies from December 2005 to February 2008 for the treatment of aortic stenosis using TAVI. Thirty patients were excluded from analysis due to failure to successfully deploy the valve in the aortic annulus. Data were collected concurrently using an ad hoc database that included operative and long-term survival. Previous cardiovascular intervention prior to TAVI was used to identify the existence of concomitant CAD. Logistic regression along with Kaplan-Meier estimates were employed to establish the association between CAD and survival from TAVI.
Overall mortality after TAVI was significantly higher among the CAD group (35.7%) in contrast with the non-CAD patients (18.4%), p = 0.01. Logistic regression analysis found that patients who had CAD were 10.1 times more likely to die (95% confidence interval 2.1 to 174.8) within 30 days of the procedure than those who did not. Proportional hazards analysis established that the risk of dying at any point in time was 2.3 times higher among the patients with CAD (95% confidence interval 1.29 to 4.17). Kaplan-Meier survival curves demonstrate improved long-term survival among patients without CAD.
Coexisting coronary artery disease negatively impacts procedural outcomes and long-term survival in patients undergoing TAVI, and implies that risk assessment and anticipated outcomes might be inaccurate due to stratification as isolated aortic valve replacement rather than AVR+CABG. Comparison of procedural outcomes, based on operative approach without controlling for unequal distribution of CAD in the cohorts, are likely invalid.
We present an optically induced remanent photostriction in BiFeO_{3}, resulting from the photovoltaic effect, which is used to modify the ferromagnetism of Ni film in a hybrid BiFeO_{3}/Ni structure. ...The 75% change in coercivity in the Ni film is achieved via optical and nonvolatile control. This photoferromagnetic effect can be reversed by static or ac electric depolarization of BiFeO_{3}. Hence, the strain dependent changes in magnetic properties are written optically, and erased electrically. Light-mediated straintronics is therefore a possible approach for low-power multistate control of magnetic elements relevant for memory and spintronic applications.
Carbon Fibre Reinforced Polymer composite (CFRP) is widely used in the aerospace industry, but is prone to delamination, which is a major causes of failure. Structural Health Monitoring (SHM) systems ...need to be developed to determine the damage occurring within it. Our motivation is to design cost-effective new sensors and a data acquisition system for magnetostrictive structural health monitoring of aerospace composites using a simple RLC circuit. The developed system is tested on magnetostrictive FeSiB and CoSiB actuator ribbons using a bending rig. Our results show detectable sensitivity of inductors as low as 0.6 μH for a bending rig radii between 600 to 300 mm (equivalent to 0.8 to 1.7 mStrain), which show a strain sensitivity resolution of 0.01 μStrain (surface area: ~36 mm
). This value is at the detectability limit of our fabricated system. The best resolution (1.86 μStrain) was obtained from a 70-turn copper (~64 μH) wire inductor (surface area: ~400 mm
) that was paired with a FeSiB actuator.
1. Climate change is affecting species distributions and will increasingly do so. However, current understanding of which individuals and species are most likely to survive and why is poor. Knowledge ...of assemblage or community level effects is limited and the balance of mechanisms that are important over different time-scales is poorly described. Laboratory experiments on marine animals predominantly employ rates of change 10-100 000 times faster than climate induced oceanic warming. To address this failure we investigated differences in individual and species abilities to tolerate warming, and also how rate of warming affected survival. 2. This study identifies community level effects of thermal biology by applying a multi-species, multi-trophic level approach to the analysis of temperature limits. 3. Within species analyses of 14 species from 6 phyla showed smaller individuals survived to higher temperatures than large animals when temperatures were raised acutely. If this trend continues at slower warming rates, the early loss of larger individuals has marked consequences at the population level as larger individuals form the major reproductive component. 4. Between species comparisons showed active species survived to higher temperatures than sessile or low activity groups. Thus active groups (e.g. predators) and juvenile or immature individuals should fare better in rapid warming scenarios. This would be expected to produce short-term ecological imbalances in warming events. 5. The rate of warming markedly affected temperature limits in a wide range of Antarctic marine species. Different species survived to temperatures of 8·3-17·6 °C when temperatures were raised by around 1 °C day⁻¹. However they only survived to temperatures between 4·0 °C and 12·3 °C when temperatures were raised by around 1-2 °C week⁻¹, and temperatures of only 1·0-6·0 °C were tolerated for acclimations over periods of months. 6. Current models predicting range changes of species in response to climate change are either correlative or mechanistic. Mechanistic models offer the potential to incorporate the ecophysiological adaptation and evolutionary processes which determine future responses and go beyond simple correlative approaches. These models depend on the incorporation of data on species capacities to resist and adapt to change. This study is an important step in the provision of such data from experimental manipulations.
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