Revealing nanomechanical deformation at the interface and degradation in all-thin-film inorganic electrochromic devices.

Recently, progress in electrochromic (EC) devices has been made in optimizing electrode and device configurations and performance. However, the ion insertion/de-insertion induced charge transfer (CT) nanomechanical effect has remained unexplored, i.e., repetitive electrode size changes at the nanoscale and stress/strain generated during electrochemical cycling, which is the focus of this work due to its intimate correlation with the elastic and plastic deformation at the interface. Considering the intervalence electrons, excellent electrochemical kinetics, and dramatic color changes, tungsten oxide (WO3) and nickel oxide (NiO) films are configured as the EC cathode and anode materials, respectively, within a full device. Upon extended cycles (>10 000), the void generation and delamination that occurred at the interface account for performance decay. Encouraged by the findings, nanoindentation mechanical tests and electrical kelvin probe force microscopy were employed to investigate the CT induced effects at the interface. There is a dramatic increase of up to 45% in the elastic Young's modulus in colored/charged WO3 at ∼40 mC cm-2. The correlation between CT and synergistic mechanical effect is interpreted by the Lippman equation. Interestingly, despite the charged state (colored; lithiated) with a relatively flat morphology bringing an ∼3.4 times higher electrostatic surface potential, the electrical work function unexpectedly decreases, arising from the dominant effect of the dipole layer potential over the chemical potential. The interatomic cohesive energy and equilibrium distance increase bury the seeds for mechanical deformation in the long run. This work provides fundamental insights into electro-chemo mechanics and interdisciplinary concerted interfacial effects at the nano/atomic level. The dependence of surface potential, stress, work function, and cohesive energy on electrochemical kinetics has been interpreted.

The utility of a multi-orifice epidural catheter when using the "Spray-as-You-Go" technique for topical Airway Anesthesia during Flexible Bronchoscopy, a randomised trial.

BACKGROUND: Lidocaine administered through the working channel of a flexible bronchoscope can provide effective local anesthesia but cannot achieve good distribution in the airway. This study was undertaken to determine whether lidocaine delivered via a multi-orifice epidural catheter (three orifices/openings) is superior to conventional method and if a better distribution and decreased the cough reflex can be achieved. METHODS: The patients (N = 100; 50 in each group) were randomized to receive either topical airway anesthesia by the "spray-as-you-go" technique via conventional application (group C) through the working channel of the bronchoscope or via a triple-orifice epidural catheter (group E). The primary outcome measurement was the cough severity, which was documented using a 4-point scale. Bronchoscopists and nurses assessed the coughing. The visual analogue scale (VAS) score for cough, total consumption of propofol and lidocaine, requirement frequency of propofol and topical anesthesia, PACU retention time, and adverse events were also compared. RESULTS: There was a significant difference in the median cough severity scores between the two groups (group C: 3 vs. group E: 2, P = 0.004). The median visual analogue scale (VAS) scores for the cough, were significantly higher in group C than those in group E (bronchoscopist: 3 vs. 2 P = 0.002; nurse: 3 vs. 2, P < 0.001). The incidence of cough was significantly higher in group C in the trachea, left and right bronchi. The highest respiratory rate was higher in group C than in group E (P < 0.01). Eight patients in group C and two patients in group E had an oxygen saturation below 90% during flexible bronchoscopy(FB) (P = 0.046). More patients in group C required extra topical anesthesia than in group E (P < 0.001). The total lidocaine consumption was also higher in group C than that in group E (P < 0.001). CONCLUSIONS: Endotracheal topical anesthesia via the multi-orifice epidural catheter (three holes/openings) during flexible bronchoscopy using the "spray-as-you-go" technique was appeared to be superior to the conventional method.

Aqueous/non-aqueous electrolyte tradeoffs in charge transfer and electrochromics of pseudocapacitive oxide films.

Environmental sustainability, safety, cost, and performance are the driving metrics for modern technological developments. Progress in these realms has been made for electrochromic (EC) devices by optimizing anode/cathode electrode materials. Yet, by these standards, the role of the electrolyte has remained unexplored. This investigation on charge transfer mechanisms at the electrolyte/electrode interface facilitates a contrast of the aqueous and non-aqueous electrolytes studied. A classic EC, high-performing, non-aqueous, lithium chlorine oxide in propylene carbonate (PC-LiClO4) is examined against a non-flammable, low reactive, cost-effective, aqueous, potassium hydroxide (KOH) electrolyte; to strengthen the understanding of electrochromics the electrolytes are referenced against the anodic EC nickel oxide (NiO) thin films. The KOH presents as a diffusion dominant response, supported by the findings of the cyclic voltammetry and electrochemistry impedance data (b = 0.56, 45°âˆ ), respectively, compared to the more surface capacitive PC-LiClO4 (b = 0.68, 60°âˆ ). Interestingly, despite the KOH full redox potential window being half the PC-LiClO4, the KOH system's current density reached more than 3 times higher than PC-LiClO4. Additionally, realizing the same current density (2 mA cm-2) in multi-step chronoamperometry, the required potential is ∼5 times lower for KOH than for PC-LiClO4 electrolyte, albeit the KOH has a longer response time. Inherent tradeoffs in the systems are considered for theoretical analysis of these phenomena, i.e., molar mass, ionization energy, viscosity, etc. The chemical nature of the electrolyte shows a profound effect on electrochemical kinetics at the NiO/electrolyte interface, pointing to the significance of all aspects in an electrochemical cell. The coupled effect of the electrolyte composition/electrode material pairing dictates the charge-storage mechanisms (and subsequently, EC properties). Furthermore, knowledge of contrasts in electrolyte type is of great interest to the scientific community for the modern metric-based optimizations of many other clean energy systems.

The role of NMDA receptors in rat propofol self-administration.

BACKGROUND: Propofol is among the most frequently used anesthetic agents, and it has the potential for abuse. The N-methyl-D-aspartate (NMDA) receptors are key mediators neural plasticity, neuronal development, addiction, and neurodegeneration. In the present study, we explored the role of these receptors in the context of rat propofol self-administration. METHODS: Sprague-Dawley Rats were trained to self-administer propofol (1.7 mg/kg/infusion) using a fixed-ratio (FR) schedule over the course of 14 sessions (3 h/day). After training, rats were intraperitoneally administered the non-competitive NDMA receptor antagonist MK-801, followed 10 min later by a propofol self-administration session. RESULTS: After training, rats successfully underwent acquisition of propofol self-administration, as evidenced by a significant and stable rise in the number of active nose-pokes resulting in propofol administration relative to the number of control inactive nose-pokes (P < 0.01). As compared to control rats, rats that had been injected with 0.2 mg/kg MK-801 exhibited a significantly greater number of propofol infusions (F (3, 28) = 4.372, P < 0.01), whereas infusions were comparable in the groups administered 0.1 mg/kg and 0.4 mg/kg of this compound. In addition, MK-801 failed to alter the numbers of active (F (3, 28) = 1.353, P > 0.05) or inactive (F (3, 28) = 0.047, P > 0.05) responses in these study groups. Animals administered 0.4 mg/kg MK-801 exhibited significantly fewer infusions than animals administered 0.2 mg/kg MK-801 (P = 0.006, P < 0.01). In contrast, however, animals in the 0.4 mg/kg MK-801 group displayed a significant reduction in the number of active nose-poke responses (F (3, 20) = 20.8673, P < 0.01) and the number of sucrose pellets (F (3, 20) = 23.77, P < 0.01), while their locomotor activity was increased (F (3, 20) = 22.812, P < 0.01). CONCLUSION: These findings indicate that NMDA receptors may play a role in regulating rat self-administration of propofol.

Life-cycling and uncovering cation-trapping evidence of a monolithic inorganic electrochromic device: glass/ITO/WO3/LiTaO3/NiO/ITO.

The visualization of the microstructure change and of the depth of lithium transport inside a monolithic ElectroChromic Device (ECD) is realized using an innovative combined approach of Focused Ion Beam (FIB), Secondary Ion Mass Spectrometry (SIMS) and Glow Discharge Optical Emission Spectroscopy (GDOES). The electrochemical and optical properties of the all-thin-film inorganic ECD glass/ITO/WO3/LiTaO3/NiO/ITO, deposited by magnetron sputtering, are measured by cycling voltammetry and in situ transmittance analysis up to 11 270 cycles. A significant degradation corresponding to a decrease in the capacity of 71% after 2500 cycles and of 94% after 11 270 cycles is reported. The depth resolved microstructure evolution within the device, investigated by cross-sectional cutting with FIB, points out a progressive densification of the NiO layer upon cycling. The existence of irreversible Li ion trapping in NiO is illustrated through the comparison of the compositional distribution of the device after various cycles 0, 100, 1000, 5000 and 11 270. SIMS and GDOES depth profiles confirm an increase in the trapped Li content in NiO as the number of cycles increases. Therefore, the combination of lithium trapping and apparent morphological densification evolution in NiO is believed to account for the degradation of the ECD properties upon long term cycling of the ECD.