The parasitic reactions associated with reduced oxygen species and the difficulty in achieving the high theoretical capacity have been major issues plaguing development of practical nonaqueous Li-O2 ...batteries. We hereby address the above issues by exploring the synergistic effect of 2,5-di-tert-butyl-1,4-benzoquinone and H2O on the oxygen chemistry in a nonaqueous Li-O2 battery. Water stabilizes the quinone monoanion and dianion, shifting the reduction potentials of the quinone and monoanion to more positive values (vs Li/Li+). When water and the quinone are used together in a (largely) nonaqueous Li-O2 battery, the cell discharge operates via a two-electron oxygen reduction reaction to form Li2O2, with the battery discharge voltage, rate, and capacity all being considerably increased and fewer side reactions being detected. Li2O2 crystals can grow up to 30 μm, more than an order of magnitude larger than cases with the quinone alone or without any additives, suggesting that water is essential to promoting a solution dominated process with the quinone on discharging. The catalytic reduction of O2 by the quinone monoanion is predominantly responsible for the attractive features mentioned above. Water stabilizes the quinone monoanion via hydrogen-bond formation and by coordination of the Li+ ions, and it also helps increase the solvation, concentration, lifetime, and diffusion length of reduced oxygen species that dictate the discharge voltage, rate, and capacity of the battery. When a redox mediator is also used to aid the charging process, a high-power, high energy density, rechargeable Li-O2 battery is obtained.
The parasitic reactions associated with reduced oxygen species and the difficulty in achieving the high theoretical capacity have been major issues plaguing development of practical nonaqueous Li-O
...batteries. We hereby address the above issues by exploring the synergistic effect of 2,5-di-tert-butyl-1,4-benzoquinone and H
O on the oxygen chemistry in a nonaqueous Li-O
battery. Water stabilizes the quinone monoanion and dianion, shifting the reduction potentials of the quinone and monoanion to more positive values (vs Li/Li
). When water and the quinone are used together in a (largely) nonaqueous Li-O
battery, the cell discharge operates via a two-electron oxygen reduction reaction to form Li
O
, with the battery discharge voltage, rate, and capacity all being considerably increased and fewer side reactions being detected. Li
O
crystals can grow up to 30 μm, more than an order of magnitude larger than cases with the quinone alone or without any additives, suggesting that water is essential to promoting a solution dominated process with the quinone on discharging. The catalytic reduction of O
by the quinone monoanion is predominantly responsible for the attractive features mentioned above. Water stabilizes the quinone monoanion via hydrogen-bond formation and by coordination of the Li
ions, and it also helps increase the solvation, concentration, lifetime, and diffusion length of reduced oxygen species that dictate the discharge voltage, rate, and capacity of the battery. When a redox mediator is also used to aid the charging process, a high-power, high energy density, rechargeable Li-O
battery is obtained.
There is limited published data on combat ocular trauma (COT) among local nationals managed at deployed United States (US) and United Kingdom (UK) military hospitals in recent conflicts. We report ...the epidemiology and outcomes of COT from a deployed military hospital in Afghanistan.
In this retrospective case series, consecutive injuries requiring ophthalmic surgery at a military hospital in Afghanistan where the sole US and UK ophthalmologist(s) were deployed between January 2017 and September 2019 were reviewed. The main outcomes were mean post-operative visual acuity (VA) in open and closed globe injury and the incidence of retinal detachment after open globe repair.
There were 102 eyes of 84 patients who had ocular injuries and underwent ophthalmic surgery at the military hospital. Most patients were male (81 96%) and were local nationals (71 85%). Blast exposure (82 80%) was the most common mechanism of injury. Mean post-operative VA was 1.24 ± 2.29 logMAR (20/348 Snellen equivalent) in open globe injury and 1.59 ± 1.17 logMAR (20/778 Snellen equivalent) in closed globe injury. After open globe repair, retinal detachment developed in 8 of 18 (44%) eyes.
COT injuries often resulted in poor post-operative VA and retinal detachment after open globe repair was common. The high incidence and severity of COT sustained by local civilians and combatants in this study may support programs to increase the availability and wear of combat eye protection among local nationals partnered with US and coalition troops.
Purpose
The ischiofemoral distance (IFD), defined as the distance between the ischial tuberosity and the lesser trochanter of the femur, is gaining recognition as an extra-articular cause of hip ...pain. It is unknown whether the IFD is influenced by the frontal knee alignment. The aim of this study was to determine the influence of realignment surgery around the knee on the IFD. It was hypothesized that valgisation osteotomy around the knee is associated with reduction of the IFD.
Methods
A consecutive series of 154 patients undergoing frontal realignment procedures around the knee in 2017 were included in this study. Long-leg standing radiographs were obtained before surgery and postoperatively. The IFD was measured between the ischium and the lesser trochanter at three different levels (proximal, middle and distal margins of the lesser trochanter parallel to the horizontal orientation of the pelvis) on standardized long-leg radiographs with the patient in upright standing position. The knee alignment was determined by measuring the hip knee ankle angle, mechanical lateral distal femur angle and the medial mechanical proximal tibia angle. Linear regression was performed to determine the influence of the change of frontal knee alignment on the IFD.
Results
Linear regression showed a direct influence of the overall change in frontal knee alignment on the IFD of the hip, regardless of the site of the osteotomy (β-0.4, confidence-interval − 0.5 to − 0.3,
p
< 0.001). Valgisation osteotomy around the knee induced a significant reduction of the ipsilateral IFD (
p
< 0.001), while varisation osteotomy induced a significant increase (
p
< 0.001). The amount of ISD change was 0.4 mm per corresponding degree of change in frontal knee alignment.
Conclusion
These findings are relevant to both the hip and knee surgeons when planning an osteotomy or arthroplasty procedure. Correction of a malalignment of the knee may resolve an ischiofemoral conflict in the hip. The concept deserves inclusion in the diagnostic workup of both the hip and knee joints.
Level of evidence
IV.
Observations of metal absorption systems in the spectra of distant quasars allow one to constrain a possible variation of the fine-structure constant throughout the history of the Universe. Such a ...test poses utmost demands on the wavelength accuracy and previous studies were limited by systematics in the spectrograph wavelength calibration. A substantial advance in the field is therefore expected from the new ultra-stable high-resolution spectrograph E
SPRESSO
, which was recently installed at the VLT. In preparation of the fundamental physics related part of the E
SPRESSO
GTO program, we present a thorough assessment of the E
SPRESSO
wavelength accuracy and identify possible systematics at each of the different steps involved in the wavelength calibration process. Most importantly, we compare the default wavelength solution, which is based on the combination of Thorium-Argon arc lamp spectra and a Fabry-Pérot interferometer, to the fully independent calibration obtained from a laser frequency comb. We find wavelength-dependent discrepancies of up to 24 m s
−1
. This substantially exceeds the photon noise and highlights the presence of different sources of systematics, which we characterize in detail as part of this study. Nevertheless, our study demonstrates the outstanding accuracy of E
SPRESSO
with respect to previously used spectrographs and we show that constraints of a relative change of the fine-structure constant at the 10
−6
level can be obtained with E
SPRESSO
without being limited by wavelength calibration systematics.
Part 6: Electrical Therapies Link, Mark S.; Atkins, Dianne L.; Passman, Rod S. ...
Circulation (New York, N.Y.),
11/2010, Letnik:
122, Številka:
18_suppl_3
Journal Article
The parasitic reactions associated with reduced oxygen species and the difficulty in achieving the high theoretical capacity have been major issues plaguing development of practical non-aqueous Li-O2 ...batteries. We hereby address the above issues by exploring the synergistic effect of 2,5-di-tert-butyl-1,4- benzoquinone and H2O on the oxygen chemistry in a non-aqueous Li-O2 battery. Water stabilizes the quinone monoanion and dianion, shifting the reduction potentials of the quinone and monoanion to more positive values (vs. Li+). When water and the quinone are used together in a (largely) non-aqueous Li-O2 battery, the cell discharge operates via a two-electron oxygen reduction reaction to form Li2O2, the battery discharge voltage, rate, capacity all being considerably increased and fewer side reactions being detected; Li2O2 crystals can grow up to 30 um, more than an order of magnitude larger than cases with the quinone alone or without any additives, suggesting that water is essential to promoting a solution dominated process with the quinone on discharging. The catalytic reduction of O2 by the quinone monoanion is predominantly responsible for the attractive features mentioned above. Water stabilizes the quinone monoanion via hydrogen bond formation and by coordination of the Li+ ions, and it also helps increase the solvation, concentration, life time and diffusion length of reduced oxygen species that dictate the discharge voltage, rate and capacity of the battery. When a redox mediator is also used to aid the charging process, a high-power, high energy- density, rechargeable Li-O2 battery is obtained.
Myosin-X (Myo10) is an unconventional myosin with MyTH4-FERM domains that is best known for its striking localization to the tips of filopodia and its ability to induce filopodia. Although the head ...domain of Myo10 enables it to function as an actin-based motor, its tail contains binding sites for several molecules with central roles in cell biology, including phosphatidylinositol (3,4,5)-trisphosphate, microtubules and integrins. Myo10 also undergoes fascinating long-range movements within filopodia, which appear to represent a newly recognized system of transport. Myo10 is also unusual in that it is a myosin with important roles in the spindle, a microtubule-based structure. Exciting new studies have begun to reveal the structure and single-molecule properties of this intriguing myosin, as well as its mechanisms of regulation and induction of filopodia. At the cellular and organismal level, growing evidence demonstrates that Myo10 has crucial functions in numerous processes ranging from invadopodia formation to cell migration.
Exploiting geometric structure to improve the asymptotic complexity of discrete assignment problems is a well-studied subject. In contrast, the practical advantages of using geometry for such ...problems have not been explored. We implement geometric variants of the Hopcroft-Karp algorithm for bottleneck matching (based on previous work by Efrat el al.) and of the auction algorithm by Bertsekas for Wasserstein distance computation. Both implementations use k-d trees to replace a linear scan with a geometric proximity query. Our interest in this problem stems from the desire to compute distances between persistence diagrams, a problem that comes up frequently in topological data analysis. We show that our geometric matching algorithms lead to a substantial performance gain, both in running time and in memory consumption, over their purely combinatorial counterparts. Moreover, our implementation significantly outperforms the only other implementation available for comparing persistence diagrams.
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