Divalent mercury (Hg 2+ ) is highly toxic in nature and extensively found in different natural water bodies worldwide. Thus, rapid trace-level monitoring of Hg 2+ , as well as its effective removal from contaminated natural water resources, is a key ongoing concern for sustainable public health and environmental protection purposes. To address this challenging task, herein we adopted a strategy of combining the inherent benefits of fascinating porous covalent organic frameworks (COFs) and macrocyclic chemistry via judicious design and synthesis of monomers to create a dual functional polymeric platform for simultaneous ultra-trace-level detection and effective removal of Hg 2+ from aqueous solution. While doing so, a "bottom-up" self-assembly approach was adopted under solvothermal conditions to prepare a β-ketoenamine linked two-dimensional selfexfoliated luminescent covalent organic nanosheet (CON), a derivative of COFs, using a rationally designed and synthesized aromatic diamine (Mc-L1) building block grafted with a pendent naptho-1,4-dithia-15-crown-5 (Mc) macrocyclic receptor acting as a highly specific Hg 2+ binding unit. The as-synthesized robust Mc-CON selectively and efficiently detected ppb levels of Hg 2+ together with high capacity removal capability (605 mg/g) from contaminated aqueous solution under a wide range of pH (3−9) with excellent recyclability, making Mc-CON a potential candidate for realistic open-air applications.
During a 1-year period, we prospectively studied the mechanism and severity of stroke in 47 patients sustaining a cerebral infarction while taking aspirin. The mechanism of stroke was undetermined in 12 patients (26%). In the remaining 35 patients, we identified 39 potential mechanisms: large-artery atherosclerosis (19 patients, 40%), cardioembolism (15 patients, 32%), and small-vessel occlusive disease (5 patients, 11%). Of 11 patients with carotid atherosclerosis and stroke, 9 (82%) had greater than 90% carotid stenosis or occlusion; of 12 patients with stroke of undetermined mechanism, 10 (83%) had previous stroke, of which 8 were also of undetermined mechanisms. Disability after stroke was moderate or severe in 27 patients (57%). These data suggest that (1) stroke in patients taking aspirin has a variety of etiologies and frequently causes moderate or severe disability; (2) patients with carotid disease failing aspirin often have high-grade carotid stenosis or occlusion; (3) stroke of undetermined mechanism may recur more frequently than other stroke subtypes in patients taking aspirin.
Controlled tuning of magnetic anisotropy and damping is essential in ferromagnetic systems for various spintronic applications. In this context, magnetic bilayers with different thicknesses of soft (Co) and hard (Co40Fe40B20) layers have been prepared using magnetron sputtering technique by alternating the order of the constituent magnetic layers. We have observed an increase in the coercive field (HC) by increasing the thickness of the Co layer. Further, for the same constituent layers, HC increases for the case when CoFeB is at the bottom of Co. We further show that by this deposition methodology, one can systematically tune the domain structure. The line width and hence the Gilbert damping constant () of the bilayers can also be modified by alternating the order and thickness of the individual magnetic layers.
Shifts of the point of fixation between two targets aligned on one eye that are located near and far (Müller paradigm) stimulates a combined saccadic‐vergence movement. In normal subjects, this test paradigm often induces saccadic oscillations of about 0.3 degrees at 20 to 30 Hz. We measured eye movements using the magnetic search coil technique in 2 patients recovering from viral opsoclonus‐myoclonus syndrome, comparing saccadic‐vergence responses to the Müller paradigm with conjugate saccades between distant targets. Both patients exhibited intermittent conjugate ocular oscillations of about 4 to 5 degrees amplitude at about 10 Hz. Combined saccadic‐vergence movements induced these oscillations twice as often as did conjugate saccades. One patient also exhibited disjunctive ocular oscillations at 10 Hz while sustaining fixation on the near target. The Müller paradigm provides a useful clinical and experimental technique for inducing saccadic oscillations. The probable mechanism is that pontine omnipause neurons, which normally gate saccades, are inhibited during the sustained vergence movement that follows the saccadic component of the response to the Müller paradigm. Ann Neurol 2001;49:24–28
We deposited Co40Fe40B20 (hard)/Co (soft) bilayers by varying the direction of the substrate relative to the line of impinging flux of sputtered atoms of the constituent layers. We have chosen two orientations in which the angle between the sputter flux for Co40Fe40B20 and Co layers are 0° (parallel-configuration) and 90° (perpendicular-configuration) with respect to each other. Domain imaging and the dynamic magnetic properties have been studied by performing magneto-optic Kerr effect based microscopy and ferromagnetic resonance spectroscopy, respectively. Kerr microscopy revealed that magnetic domains for the bilayers grown in different configurations exhibit a cumulative effect of the domain structure of both the single layers. However, we found that the damping constant α for the bilayers grown in the parallel-configuration exhibit lower damping as compared to the corresponding sample grown under the perpendicular-configuration.
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