Resistive Avalanches in La1-xSrxCoO3-δ (x = 0, 0.3) Thin Films and Their Reversible Evolution by Tuning Lattice Oxygen Vacancies (δ).

Strong correlations are often manifested by exotic electronic phases and phase transitions. LaCoO3-δ (LCO) is a system that exhibits such strong electronic correlations with lattice-spin-charge-orbital degrees of freedom. Here, we show that mesoscopic oxygen-deficient LCO films show resistive avalanches of about 2 orders of magnitude due to the metal-insulator transition (MIT) of the film at about 372 K for the 25 W RF power-deposited LCO film on the Si/SiO2 substrate. In bulk, this transition is otherwise gradual and occurs over a very large temperature range. In thin films of LCO, the oxygen deficiency (0 < δ < 0.5) is more easily reversibly tuned, resulting in avalanches. The avalanches disappear after vacuum annealing, and the films behave like normal insulators (δ ∼0.5) with Co2+ in charge ordering alternatively with Co3+. This oxidation state change induces spin state crossovers that result in a spin blockade in the insulating phase, while the conductivity arises from hole hopping among the allowed cobalt Co4+ ion spin states at high temperature. The chemical pressure (strain) of 30% Sr2+ doping at the La3+ site results in reduction in the avalanche magnitude as well as their retention in subsequent heating cycles. The charge nonstoichiometry arising due to Sr2+ doping is found to contribute toward hole doping (i.e., Co3+ oxidation to Co4+) and thereby the retention of the hole percolation pathway. This is also manifested in energies of crossover from the 3D variable range hopping (VRH) type transport observed in the temperature range of 300-425 K, while small polaron hopping (SPH) is observed in the temperature range of 600-725 K for LCO. On the other hand, Sr-doped LCO does not show any crossover and only the VRH type of transport. The strain due to Sr2+ doping refrains the lattice from complete conversion of δ going to 0.5, retaining the avalanches.

Face mask use in the city of Chennai, India: Results from three serial cross-sectional surveys, 2021.

INTRODUCTION: The Government of Tamil Nadu, India, mandated wearing face masks in public places to combat the COVID-19 pandemic. We established face mask surveillance and estimated the prevalence of appropriate mask use (covering the nose, mouth, and chin) in the slums and non-slums of Chennai at different time points in 2021. METHODS: We conducted three serial cross-sectional surveys in the outdoors and indoors of Chennai in March, July, and October 2021. We observed the mask wearing among 3200 individuals in the outdoors and 1280 in the indoors. We divided the outdoor and indoor locations into slums and non-slums. In October 2021, we also surveyed 150 individuals from each of the 11 shopping malls in the city. We calculated the proportions and 95% confidence interval (95%CI) for the appropriate mask use in the outdoor, indoor, and malls by age, gender, region, and setting (slum and non-slum). RESULTS: We observed 3200 individuals in the outdoor and 1280 individuals in the indoor setting, each from a slum and non-slum, during the three rounds of the study. In outdoor and indoors, males comprised three-fourths and middle-aged individuals were half the study population. Mask compliance changed significantly with time (p-value <0.001). Males consistently demonstrated better compliance in all rounds. The south region had the highest mask compliance in slums indoors and outdoors in rounds 4 and 5. Young adults had the highest mask compliance in both outdoor slums and non-slums in all rounds. Overall mask compliance in shopping malls was 57% (95% CI: 48-65). CONCLUSION: The mask compliance in Chennai outdoors during the COVID-19 pandemic was less than 50%, with variations across time points by gender, age groups, and geographical locations. We must develop more effective communication strategies for older age groups and crowded indoor settings.

Audit of operation theater time utilization with perspective to optimize turnaround times and theater output.

Background and Aims: Operation theater (OT) complex is an important area for a hospital as it needs expensive infrastructure, disposable, and reusable resources and a multidisciplinary highly qualified and efficient team, the metrics of which are key in generating revenue, and improved productivity. The efficient utilization of OT ensures maximum output in view of the investment of highly qualified doctors, equipment, and outcomes. Our study aimed to evaluate the utilization of OT functioning stepwise, reasons for delays, case cancellations, and areas of improvement if any. Material and Methods: This prospective observational study was planned in three phases; in phase 1 audit of OT functioning was carried out for 1 month and based on data analysis recommendations were given for improvement. In phase 2, the recommendations would be implemented over 3 months and in phase 3 re-audit will be carried out for 1 month. Data analysis was done on IBM SPSS version 26 software. Descriptive statistics measures were calculated by the mean and standard deviation. Results: The total available resource time was 52920 min and the total time utilized was 37740 min. Overall, raw utilization was 71.31%. OT was started late 63.50% times. Case cancellation occurred on 8.99% occasions. Conclusion: We conclude that utilization of operating room time can be maximized by proper planning and realistic scheduling of elective lists, communication among team members, and resource management. Audit of OT utilization is an important tool to identify problem areas and formulate protocols accordingly.

Comparison of bleb morphology by anterior segment optical coherence tomography and clinical outcome after phacotrabeculectomy with mitomycin C or Ologen implant.

PURPOSE: To compare the bleb morphology by Anterior Segment Optical Coherence Tomography (ASOCT) and clinical outcome after Phacotrabeculectomy with either mitomycin C or Ologen implant. METHODS: In a prospective interventional active controlled study, 93 patients aged 18 years and above underwent phacotrabeculectomy with either mitomycin C (53 eyes) or ologen implant (40 eyes), followed up for 12 months. The primary outcome measure was to note the evolution of bleb morphology by ASOCT in the two groups over 12 months. Secondary outcome measures were mean IOP, reduction in the need for anti-glaucoma medications, and complications seen in the two groups. RESULTS: All parameters in the two groups were comparable preoperatively (P>0.05). Best corrected visual acuity at 12 months was 0.38±0.27 in mitomycin group and 0.31±0.23 in ologen group (P=0.151). Post-operative IOP at 12 months was 14.09±3.1mmHg (95%CI 13.22-14.97) in mitomycin group, and 13.25±2.5 mmHg (95%CI 12.40-14.30) in ologen group (P=0.254). The mean number of medications was 0.36±0.68 in mitomycin group and 0.38+/-0.70 in ologen group at 12 months (P=0.91). Overall success was achieved in 98.1 % of patients in mitomycin group and 90 % of patients in ologen group at 12 months. No major sight-threatening complications were noted in any group. AS-OCT imaging at 12 months showed multiform reflectivity with multiple large cystic spaces in both groups, with good IOP control. CONCLUSION: Phacotrabeculectomy using Mitomycin C and Ologen implant resulted in similar morphologic and functioning blebs at one year with comparable efficacy in controlling intraocular pressure.