Binder-free Li-O2 battery cathodes using Ni- and PtRu-coated vertically aligned carbon nanofibers as electrocatalysts for enhanced stability

The development of an ideal cathode for Li-O2 battery (LOB) has been a great challenge in achieving high discharge capacity, enhanced stability, and longevity. The formation of undesired and irreversible discharge products on the surface of current cathode materials limit the life span of the LOB. In this study, we report the systematic electrochemical study to compare the performance of LOB employing a unique graphitic nanostructured carbon architecture, i.e., vertically aligned carbon nanofiber (VACNF) arrays, as the cathode materials. Transition metal (Ni) and noble metal alloy (PtRu) are further deposited on the VACNF array as electrocatalysts to improve the discharge/charge processes at the cathode. The structure of as-prepared electrodes was examined with the field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy (XPS). The LOB with VACNF-Ni electrode delivered the highest specific and areal discharge capacities (14.92 Ah·g−1, 4.32 mAh·cm−2) at 0.1 mA·cm−2 current density as compared with VACNF-PtRu (9.07 Ah·g−1, 2.62 mAh·cm−2), bare VACNF (5.55 Ah·g−1, 1.60 mAh·cm−2) and commercial Vulcan XC (3.83 Ah·g−1, 1.91 mAh·cm−2). Cycling stability tests revealed the superior performance of VACNF-PtRu with 27 cycles as compared with VACNF-Ni (13 cycles), VACNF (8 cycles), and Vulcan XC (3 cycles). The superior cycling stability of VACNF-PtRu can be attributed to its ability to suppress the formation of Li2CO3 during the discharge cycle, as elucidated by XPS analysis of discharged samples. We also investigated the impact of carbon cloth and carbon fiber as cathode electrode substrate on the performance of LOB

Platinum Deposited Nitrogen-Doped Vertically Aligned Carbon Nanofibers as Methanol Tolerant Catalyst for Oxygen Reduction Reaction with Improved Durability

Nitrogen doping in carbon materials can modify the employed carbon material’s electronic and structural properties, which helps in creating a stronger metal-support interaction. In this study, the role of nitrogen doping in improving the durability of Pt catalysts supported on a three-dimensional vertically aligned carbon nanofiber (VACNF) array towards oxygen reduction reaction (ORR) was explored. The nitrogen moieties present in the N-VACNF enhanced the metal-support interaction and contributed to a reduction in the Pt particle size from 3.1 nm to 2.3 nm. The Pt/N-VACNF catalyst showed better durability when compared to Pt/VACNF and Pt/C catalysts with similar Pt loading. DFT calculations validated the increase in the durability of the Pt NPs with an increase in pyridinic N and corroborated the molecular ORR pathway for Pt/N-VACNF. Moreover, the Pt/N-VACNF catalyst was found to have excellent tolerance towards methanol crossover

Platinum Deposited Nitrogen-Doped Vertically Aligned Carbon Nanofibers as Methanol Tolerant Catalyst for Oxygen Reduction Reaction with Improved Durability

Nitrogen doping in carbon materials can modify the employed carbon material’s electronic and structural properties, which helps in creating a stronger metal-support interaction. In this study, the role of nitrogen doping in improving the durability of Pt catalysts supported on a three-dimensional vertically aligned carbon nanofiber (VACNF) array towards oxygen reduction reaction (ORR) was explored. The nitrogen moieties present in the N-VACNF enhanced the metal-support interaction and contributed to a reduction in the Pt particle size from 3.1 nm to 2.3 nm. The Pt/N-VACNF catalyst showed better durability when compared to Pt/VACNF and Pt/C catalysts with similar Pt loading. DFT calculations validated the increase in the durability of the Pt NPs with an increase in pyridinic N and corroborated the molecular ORR pathway for Pt/N-VACNF. Moreover, the Pt/N-VACNF catalyst was found to have excellent tolerance towards methanol crossover

A Comparative Study of Fine‑Needle Aspiration and Nonaspiration Cytology Diagnosis in Thyroid Lesions

Background: Aspiration cytology is one of the first-line diagnostic tests in thyroid malignancies. Fine-needle aspiration cytology (FNAC) in thyroid lesions causes hemorrhagic smear and cell trauma, often leading to the repetition of smear and delay in diagnosis. This study was conducted to identify the diagnostically superior technique with regard to thyroid swelling and to assess the quality of smears obtained from FNAC and fine-needle nonaspiration cytology (FNNAC). Methodology: This was a prospective diagnostic study carried out for 2 years in a tertiary care center from South India. All patients with complaints of thyroid swellings, after examination, underwent FNNAC, followed by FNAC of the lesion. They underwent thyroidectomy when indicated. The final postoperative biopsy reports were compared with the preoperative reports of these two techniques (FNNAC and FNAC). The quality of smears was compared using Mair's score. Results: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in diagnosing malignancy were 93.4%, 100%, 100%, 98.78%, and 98.96% for FNNAC and 94.12%, 100%, 100%, 98.82%, and 99% for FNAC, respectively, which were comparable. Regarding the quality of smears, FNNAC had more smears with less blood in the background. FNAC had more smears with adequate cellularity. The difference in overall Mair's score between the two techniques was not significant (P = 0.28). Conclusion: No difference was found in the accuracy of FNAC and FNNAC in diagnosing thyroid lesions. Furthermore, the smear quality of both techniques was comparable. Hence, either can be used based on the operator's preference and experience

Is There an Association between Variceal Bleed and Helicobacter pylori Infection in Cirrhotic Patients with Portal Hypertension? A prospective cohort study

Objectives: The objective of this study was to find the association of H. pylori in patients with variceal bleeding as well as rebleeding in cases of cirrhosis with portal hypertension. Methods: This was a prospective cohort of patients with bleeding esophageal varices. The primary outcome was correlation between prevalence of H. pylori and the incidence of bleeding/ rebleeding from varices and with encephalopathy. The secondary outcome were correlation between the site of bleeding with H. pylori infection and the association of pepsinogen I & II and the ratio of pepsinogen I/II with bleeding. Results: A total of 190 patients were assessed for eligibility, out of which 159 patients were included in this study. 124 out of 159 patients (77.9%) had alcohol-related liver disease. 8 out of 159 patients had HBV-related liver disease. 7 patients with varices had neither bled at presentation nor did bleed in the follow-up period. A total of 78 out of 159 (49.05%) patients were H.pylori-infected. Patients with esophageal varices [Adjusted Risk (AR)=0.7] and H.pylori infection (AR=0.7) had a lower risk of variceal rebleeding. Among the patients negative for H.pylori, pepsinogen I was higher in patients with rebleeding (30.7 vs 14.4; p<0.001). Among H.pylori positive patients, the ratio of pepsinogen I/II was higher in patients with rebleeding (2.9 vs 1.3; p=0.023). Conclusion: H.pylori infection was associated with a lower risk of rebleeding in cases of cirrhosis with portal hypertension. Irrespective of the status of H.pylori infection, rebleeding was associated with more gastric acid output demonstrated by the level of pepsinogen. Keywords: Pepsinogen; hepatic encephalopathy; gastric acid output, Helicobacter pylor

Drain Structural Defect Detection and Mapping Using AI-Enabled Reconfigurable Robot Raptor and IoRT Framework

Human visual inspection of drains is laborious, time-consuming, and prone to accidents. This work presents an AI-enabled robot-assisted remote drain inspection and mapping framework using our in-house developed reconfigurable robot Raptor. The four-layer IoRT serves as a bridge between the users and the robots, through which seamless information sharing takes place. The Faster RCNN ResNet50, Faster RCNN ResNet101, and Faster RCNN Inception-ResNet-v2 deep learning frameworks were trained using a transfer learning scheme with six typical concrete defect classes and deployed in an IoRT framework remote defect detection task. The efficiency of the trained CNN algorithm and drain inspection robot Raptor was evaluated through various real-time drain inspection field trials using the SLAM technique. The experimental results indicate that robot’s maneuverability was stable, and its mapping and localization were also accurate in different drain types. Finally, for effective drain maintenance, the SLAM-based defect map was generated by fusing defect detection results in the lidar-SLAM map

Comparison of diagnoses of early-onset sepsis associated with use of Sepsis Risk Calculator versus NICE CG149: a prospective, population-wide cohort study in London, UK, 2020–2021

Objective We sought to compare the incidence of early-onset sepsis (EOS) in infants ≥34 weeks’ gestation identified >24 hours after birth, in hospitals using the Kaiser Permanente Sepsis Risk Calculator (SRC) with hospitals using the National Institute for Health and Care Excellence (NICE) guidance.Design and setting Prospective observational population-wide cohort study involving all 26 hospitals with neonatal units colocated with maternity services across London (10 using SRC, 16 using NICE).Participants All live births ≥34 weeks’ gestation between September 2020 and August 2021.Outcome measures EOS was defined as isolation of a bacterial pathogen in the blood or cerebrospinal fluid (CSF) culture from birth to 7 days of age. We evaluated the incidence of EOS identified by culture obtained >24 hours to 7 days after birth. We also evaluated the rate empiric antibiotics were commenced >24 hours to 7 days after birth, for a duration of ≥5 days, with negative blood or CSF cultures.Results Of 99 683 live births, 42 952 (43%) were born in SRC hospitals and 56 731 (57%) in NICE hospitals. The overall incidence of EOS (<72 hours) was 0.64/1000 live births. The incidence of EOS identified >24 hours was 2.3/100 000 (n=1) for SRC vs 7.1/100 000 (n=4) for NICE (OR 0.5, 95% CI (0.1 to 2.7)). This corresponded to (1/20) 5% (SRC) vs (4/45) 8.9% (NICE) of EOS cases (χ=0.3, p=0.59). Empiric antibiotics were commenced >24 hours to 7 days after birth in 4.4/1000 (n=187) for SRC vs 2.9/1000 (n=158) for NICE (OR 1.5, 95% CI (1.2 to 1.9)). 3111 (7%) infants received antibiotics in the first 24 hours in SRC hospitals vs 8428 (15%) in NICE hospitals.Conclusion There was no significant difference in the incidence of EOS identified >24 hours after birth between SRC and NICE hospitals. SRC use was associated with 50% fewer infants receiving antibiotics in the first 24 hours of life