Electrochemistry Beyond Solutions: Modeling Particle Self-Crowding of Nanoparticle Suspensions.

Nanoparticle suspensions hold promise to transform functionality of next-generation electrochemical systems including batteries, capacitors, wastewater treatment, and sensors, challenging the limits of existing electrochemical models. Classical solution-based electrochemistry assumes that charge is transported and transferred by point-like carriers. Herein, we examine the electrochemistry of a model aqueous suspension of nondissolvable electroactive nanoparticles over a wide concentration range using a rotating disk electrode. Past a concentration and rotation rate threshold, the electrochemistry deviates from solution theory with a maximum attainable current due to particle "self-crowding" where reacted particles on the electrode surface reduce the area accessible for charge transfer by unreacted particles. The observed response is rationalized with an analytical model considering the physical adsorption/desorption kinetics and interfacial transport of nondissolvable finite-size charge carriers. Experimental validation shows the model to be applicable across a range of electrode sizes and thus suitable for engineering electrochemical systems employing nondissolvable nanoparticle suspensions.

High-Entropy Spinel Oxide Ferrites for Battery Applications.

Four different high-entropy spinel oxide ferrite (HESO) electrode materials containing 5-6 distinct metals were synthesized by a simple, rapid combustion synthesis process and evaluated as conversion anode materials in lithium half-cells. All showed markedly superior electrochemical performance compared to conventional spinel ferrites such as Fe3O4 and MgFe2O4, having capacities that could be maintained above 600 mAh g-1 for 150 cycles, in most cases. X-ray absorption spectroscopy (XAS) results on pristine, discharged, and charged electrodes show that Fe, Co, Ni, and Cu are reduced to the elemental state during the first discharge (lithiation), while Mn is only slightly reduced. Upon recharge (delithiation), Fe is reoxidized to an average oxidation state of about 2.6+, while Co, Ni, and Cu are not reoxidized. The ability of Fe to be oxidized past 2+ accounts for the high capacities observed in these materials, while the presence of metallic elements after the initial lithiation provides an electronically conductive network that aids in charge transfer.

Implementation of a Tenecteplase Protocol for Treatment of Acute Ischemic Stroke in a Health System.

Purpose. Alteplase is the standard of care for intravenous thrombolytic treatment of acute ischemic stroke, but recent evidence suggests that tenecteplase may be as safe and efficacious. The purpose of this study was to evaluate the direct cost savings, safety, and efficacy outcomes following the implementation of a tenecteplase protocol for acute ischemic stroke in the emergency departments within a health system. Methods. A multicenter retrospective medical record review was performed for 4 months prior to protocol implementation on patients who received alteplase and for 4 months post-implementation on patients who received tenecteplase. The primary outcome was the direct cost difference associated with tenecteplase. Secondary outcomes included reduction in National Institutes of Health Stroke Scale 24 hours after thrombolytic therapy, door-to-needle time, symptom onset to intravenous thrombolysis time, incidence of adverse effects, and death. Results. Pre-implementation, 102 received alteplase and post-implementation, 117 received tenecteplase. Four months of utilization of tenecteplase resulted in direct cost savings of $209,476.80 for the health system, which translates to roughly $2,000 per patient. Reduction in the National Institutes for Health Stroke Scale were similar between the two groups with -3.96 in alteplase and -3.18 in tenecteplase (p = 0.952). Median door-to-needle time was 44.5 minutes in alteplase and 49 minutes in tenecteplase. Adverse events occurred in 19 patients in alteplase and 19 in tenecteplase (p = 0.573). Death occurred in 9 patients in alteplase and 14 patients in tenecteplase (p = 0.376). Conclusion. A tenecteplase protocol was successfully implemented in the healthcare system resulting in direct cost savings with no significant differences in adverse events.