Spectroscopic and Electrochemical Exploration of Carbon-Infused Intercalation-Type Spinel Composite for Aqueous Systems.

Lithium-manganese-based compounds are promising intercalation host materials for aqueous battery systems due to their synergy with high ionic conductive aqueous electrolytes, safety, eco-friendliness, and low cost. Yet, due to poor electrical conductivity and trapping of diffused electrolyte cations within its crystal formation, achieving optimum cycle stability and rate capability remains a challenge. This unfortunately limits their use in modern day high-powered devices, which require quality output with high reliability. Here, the authors propose a facile method to produce LiMn2O4 and LiFe0.5Mn0.5PO4 and compare their structural stability and corresponding electrochemical performance by controlling the interfacial layer through multi-walled carbon nanotubes' (MWCNTs) infusion. High-resolution scanning electron microscopy results revealed that the active particles were connected by MWCNT via the formation of a three-dimensional wiring network, suggesting that stronger interfacial bonding exists within the composite. As a result, the conducting composite decreases the electron transport distance with an increased number of active sites, thus accelerating the lithium ion intercalation/de-intercalation process. Compared to C/LMO with a Rct of 226.3 Ω and change transfer (io) of 2.75 × 10-3, the C/LFMPO-composite has a reduced Rct of 138 Ω and enhanced rate of 1.86 × 10-4 A cm-2. The faster kinetics can be attributed to the unique synergy between the conductive MWCNTs and the contribution of both single-phase and two-phase regions in Li1-x(Fe,Mn)PO4 during Li+ extraction and insertion. The electrochemical features before and after modification correlate well with the interplanar distance of the expanded manganese and manganese phosphate layers shown by their unique surface features, as analyzed by advanced spectroscopy techniques. The results reveal that MWCNTs facilitate faster electron transmission whilst maintaining the stability of the host framework, which makes them favorable as next generation cathode materials.

Humidity Sensing Applications of Lead-Free Halide Perovskite Nanomaterials.

Over the past decade, perovskite-based nanomaterials have gained notoriety within the scientific community and have been used for a variety of viable applications. The unique structural properties of these materials, namely good direct bandgap, low density of defects, large absorption coefficient, high sensitivity, long charge carrier lifetime, good selectivity, acceptable stability at room temperature, and good diffusion length have prompted researchers to explore their potential applications in photovoltaics, light-emitting devices, transistors, sensors, and other areas. Perovskite-based devices have shown very excellent sensing performances to numerous chemical and biological compounds in both solid and liquid mediums. When used in sensing devices, Perovskite nanomaterials are for the most part able to detect O2, NO2, CO2, H2O, and other smaller molecules. This review article looks at the use of lead-free halide perovskite materials for humidity sensing. A complete description of the underlying mechanisms and charge transport characteristics that are necessary for a thorough comprehension of the sensing performance will be provided. An overview of considerations and potential recommendations for the creation of new lead-free perovskite nanostructure-based sensors is presented.

The Synergistic Properties and Gas Sensing Performance of Functionalized Graphene-Based Sensors.

The detection of toxic gases has long been a priority in industrial manufacturing, environmental monitoring, medical diagnosis, and national defense. The importance of gas sensing is not only of high benefit to such industries but also to the daily lives of people. Graphene-based gas sensors have elicited a lot of interest recently, due to the excellent physical properties of graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO). Graphene oxide and rGO have been shown to offer large surface areas that extend their active sites for adsorbing gas molecules, thereby improving the sensitivity of the sensor. There are several literature reports on the promising functionalization of GO and rGO surfaces with metal oxide, for enhanced performance with regard to selectivity and sensitivity in gas sensing. These synthetic and functionalization methods provide the ideal combination/s required for enhanced gas sensors. In this review, the functionalization of graphene, synthesis of heterostructured nanohybrids, and the assessment of their collaborative performance towards gas-sensing applications are discussed.

Health after Legionnaires' disease: A description of hospitalizations up to 5 years after Legionella pneumonia.

BACKGROUND AND OBJECTIVES: Research on Legionnaires' Disease (LD) suggests there may be long-term health complications, but data are limited. This study investigated whether Intensive Care Unit (ICU) admission during LD hospitalization may be associated with adverse health outcomes and characterized subsequent discharge diagnoses in patients with LD up to 5 years post-LD. METHODS: We conducted a retrospective case series study with follow up for 5 years among patients hospitalized at a Department of Veterans Affairs (VA) Medical Center between 2005 and 2010 with LD. Data were collected from medical records on health history, LD severity (including ICU admission), and discharge diagnoses for 5 years post-LD or until death. We used ordinal logistic regression to explore associations between ICU admission and hospitalizations post-LD. Frequency counts were used to determine the most prevalent discharge diagnoses in the 5 years post-LD. RESULTS: For the 292 patients with laboratory-confirmed LD, those admitted to the ICU during LD hospitalization were more likely to have a greater number of hospitalizations within 5 years compared to non-ICU patients (ORHosp 1.92 CI95% 1.25, 2.95). Fifty-five percent (161/292) had ≥ 1 hospitalization within 5 years post-LD. After accounting for pre-existing diagnosis codes in patients with at least one hospitalization in the 2 years prior to LD (n = 77/161 patients, 47.8%), three of the four most frequent new diagnoses in the 5 years post-LD were non-chronic conditions: acute renal failure (n = 22, 28.6%), acute respiratory failure (n = 17, 22.1%) and unspecified pneumonia (n = 15, 19.5%). CONCLUSIONS: Our findings indicate that LD requiring ICU admission is associated with more subsequent hospitalizations, a factor that could contribute to poorer future health for people with severe LD. In addition to chronic conditions prevalent in this study population, we found new diagnoses in the 5-year post-LD period including acute renal failure. With LD incidence increasing, more research is needed to understand conditions and factors that influence long term health after LD.

The Effect of Carbetocin Dose on Transmural Dispersion of Myocardial Repolarization in Healthy Parturients Scheduled for Elective Cesarean Delivery Under Spinal Anesthesia: A Prospective, Randomized Clinical Trial.

BACKGROUND: QT interval prolongation is associated with torsade de pointes but remains a poor predictor of drug torsadogenicity. Increased transmural dispersion of myocardial repolarization (TDR), measured as the time interval between the peak and end of the T wave (Tp-e), is a more reliable predictor. Carbetocin is recommended as an uterotonic in patients undergoing cesarean delivery (CD), but its effect on Tp-e is unknown. We evaluated the effect of carbetocin dose on Tp-e and Bazett-corrected QT intervals (QTc) during elective CD under spinal anesthesia. METHODS: On patient consent, 50 healthy parturients undergoing elective CD with a standardized spinal anesthetic and phenylephrine infusion were randomized to receive an intravenous (IV) bolus of carbetocin 50 µg (C50) or 100 µg (C100) via an infusion pump over 1 minute. A 12-lead electrocardiogram (ECG) was obtained at baseline, 5 minutes after spinal anesthesia, then 5 and 10 minutes after carbetocin administration. A cardiologist blinded to group and timing of ECGs measured QTc and Tp-e using Emori's criteria. Primary outcome was the change in Tp-e at 5 minutes after carbetocin administration between the C50 and C100 groups and within each group compared to baseline values. Secondary outcomes included occurrence of arrhythmias, changes in QTc at 5 and 10 minutes after carbetocin, changes in both QTc and Tp-e after spinal anesthesia compared to baseline between and within groups. RESULTS: Data from 41 parturients with a mean (standard deviation [SD]) age of 39.0 (0.7) years and weight of 75.0 (12.0) kg were analyzed. Between groups, at 5 minutes after carbetocin administration, Tp-e in C100 was 4.1 milliseconds longer compared to C50 (95% confidence interval [CI], 0.8-7.5; P = .01). Within groups, at 5 minutes after carbetocin administration, C50 did not significantly increase Tp-e compared to baseline (mean difference [MD] 1.9 milliseconds; 95% CI, -0.95 to 4.81 milliseconds; P = .42) but C100 did (MD 5.1 milliseconds; 95% CI, 2.1-8.1; P = .003). QTc increased significantly within C50 and C100 groups at 5 and 10 minutes after carbetocin administration (all P < .001), with no between-group differences. There were no arrhythmias. CONCLUSIONS: Tp-e was unaffected by C50 IV given after CD in healthy parturients under spinal anesthesia, but minimally prolonged by C100. The increase in QTc after carbetocin administration was statistically significant, but with no apparent dose-dependent effect. The minimal Tp-e prolongation at the higher dose is unlikely to have any clinically significant impact on TDR and therefore the risk of inducing torsade de pointes is low.

Is spinal anaesthesia in young infants really safer and better than general anaesthesia?

PURPOSE OF REVIEW: Concerns regarding the potential neurotoxic effects of general anaesthesia have seen resurgence in awake spinal anaesthesia in neonates and infants. This review includes recently published data from a large prospective randomized controlled trial with view to determining if spinal anaesthesia is safer and better than general anaesthesia in this population. RECENT FINDINGS: Compared with general anaesthesia, spinal anaesthesia results in less haemodynamic instability and fewer early (<30 min) apnoeic episodes in neonates and infants undergoing inguinal herniorraphy; the overall incidence of apnoeas in the first 12 h postoperatively was similar. Neurodevelopmental outcome 2 years postoperatively was similar. An appreciable failure rate for spinal anaesthesia was confirmed. SUMMARY: Spinal anaesthesia represents a suitable alternative to general anaesthesia in neonates and infants undergoing minor surgery avoiding the need for endotracheal intubation and ventilation. Spinal anaesthesia has some advantages but a significant failure rat and has not been demonstrated to improve neurodevelopmental outcome.