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Considering that the cathodic oxygen reduction reaction (ORR) is sluggish, it is necessary to develop efficient and durable catalysts to accelerate this reaction. Furthermore, the high cost and low abundance of Pt, which is the benchmark catalyst for the cathodic ORR, limit its widespread applications. Among the transition metals, cobalt-based materials have shown significant advancement for the reduction of oxygen molecules, which has been proven by both experimental and theoretical investigations. The high inherent catalytic ability of cobalt among the first row transition metals is the key descriptor for the widespread research in this area. Herein, we review the recent advancements in cobalt-based electrocatalysts supported on nitrogen-doped carbon towards the selective 4 e− reduction of oxygen molecules with enhanced operational durability. Furthermore, we highlight the relationship between theory and experiment to investigate the fundamental mechanism of these electrocatalysts. Finally, we present perspectives on suitable approaches for interpreting the mechanism of cobalt-based nitrogen-doped carbon towards the ORR. [ABSTRACT FROM AUTHOR]

Photoreforming biomass-derived waste such as glycerol into hydrogen fuel is a renewable hydrogen generation technology that has the potential to become important due to unavoidable CO2 production during methane steam reforming. Despite tremendous efforts, the challenge of developing highly active photocatalysts at a low cost still remains elusive. Here, we developed a novel photocatalyst with a hybrid support comprising reduced graphene oxide (rGO) and TiO2 nanorods (TNR). rGO in the hybrid support not only performed as an excellent scavenger of electrons from the semiconductor conduction band due to its suitable electrochemical potential, but also acted as an electron transport highway to the metal co-catalyst, which otherwise is not possible by simply increasing metal loading due to the shadowing effect. A series of hybrid supports with different TNR and rGO ratios were prepared by the deposition method. Pd nanoparticles were deposited over hybrid support through the chemical reduction method. Pd/rGO-TNRs photocatalyst containing 4 wt.% rGO contents in the support and 1 wt.% nominal Pd loading demonstrated hydrogen production activity ~41 mmols h−1g−1, which is 4 and 40 times greater than benchmark Au/TiO2 and pristine P25. The findings of this works provide a new strategy in optimizing charge extraction from TiO2, which otherwise has remained impossible due to a fixed tradeoff between metal loading and the detrimental shadowing effect. [ABSTRACT FROM AUTHOR]

Frequent exposure to ultraviolet (UV) radiation without any protection turns out to be a fatal threat leading to skin cancer. This can be forestalled by the direct application of sunscreen cosmetic products. The efficiency of UV absorbed energy dissipation by sunscreen can be enhanced if it contains a charge and/or energy acceptor species. 2-Phenylbenzimidazole-5-sulfonic acid (PBSA) is an artificial sunscreen component that acts as an electron donor in alliance with biocompatible and environment-friendly ZnO quantum dot (QD) acceptors. Functionalized ZnO QDs are synthesized by the colloidal method using mercaptoacetic acid (MAA), mercaptopropionic acid (MPA), L -cysteine (LC), ethylene glycol (EG), β-alanine (BA), and citric acid (CA) ligands that help to develop an interaction with the PBSA. Steady-state photoluminescence (SSPL) and time-resolved photoluminescence (TRPL) analysis were employed to study the efficiency and rate of the electron transfer (ET) process. Our findings reveal that the electron transfer rate strongly depends on the size and the nature of the functionalizing ligands. The highest ET efficiency for the PBSA-ZnO QD dyad is noticed in the case of MAA (87.9%) and the lowest with the CA (33.8%) ligand. This indicates that MAA-functionalized ZnO QDs are the best electron acceptor amongst the other aforementioned functionalizing ligands as evidenced by the cyclic voltammetry (CV) measurements of PBSA- and MAA-functionalized ZnO QDs. These findings suggest that in the case of the PBSA-ZnO QD dyad, small-sized thiol functionalizing ligands like MAA, MPA and LC facilitate the electron transfer process more than large-sized ligands containing hydroxyl and amine functionalities, such as EG, BA, and CA. [ABSTRACT FROM AUTHOR]

Objective: To assess the predictors associated with mortality within 8 weeks in patients undergoing endoscopic N-butyl-2-cyanoacrylate treatment. Study Design: Prospective comparative study. Place and Duration of Study: Department of Gastroenterology, Services Institute of Medical Sciences, Lahore Pakistan, from Mar 2018 to Mar 2019. Methodology: A total of 106 patients of gastric variceal bleed were enrolled in the study. Tissue glue was injected into the varix endoscopically and mortality within 8 weeks after endoscopic intervention was noted. Results: Among the enrolled patients, 65 (61.3%) were male and 41(38.7%) were female. Mortality was noted in 19 (17.9%) patients within 8 weeks after endoscopic therapy. Chi-square analysis showed creatinine >1.5, Child Pugh score >9, MELD score >18, re-bleeding within 7 days, low blood pressure <90/60 at presentation and hepatic encephalopathy as significant predictors of mortality (p<0.005). Conclusion: Cirrhotic patients undergoing endoscopic injection of gastric varix with N-butyl 2-cyanoacrylate after gastric variceal bleed have high risk of death within 8 weeks. [ABSTRACT FROM AUTHOR]

Objective: To determine student’s perception of bedside clinical teaching and to correlate it with their performance in assessment. Methods: This cross-sectional study of correlational survey was conducted at Services Institute of Medical Sciences in September 2019, involving students of final professional year who filled a proforma to rate their bedside teaching experience during clinical rotations using rating scale. Mean scores of items were determined with score < 3 reflecting dis-satisfaction. Mean scores were compared between high and low performing students using student’s t test. Results: Total of 160 students participated. Physical environment domain was assigned lowest scores by students (mean 2.94±0.74) followed by teaching task by teachers (3.04±0.72), group dynamics (3.16±0.81) and patient comfort and attitude towards patient (3.87±0.60). Teaching task by teacher had maximum stems with scores < 3 needing significant improvement. Students with low academic performance were more unsatisfied with group dynamics of bedside teaching (p value 0.009), especially lack of equal opportunities of participation for every member (p value <0.000) in clinical rotations. Conclusion: Small size group with adequate space for bedside training and faculty training can enhance learning experience of students. Ensuring active participation of each group member during bedside learning can improve academic performance of students. [ABSTRACT FROM AUTHOR]

Objectives: to evaluate the sustained virology response rate of Daclatasvir (DCV) + Sofos (SOF) with and without Ribavirin (RBV) for 12 and 24 weeks in patients presented with advance liver disease. Study Design: Randomized control trial. Setting: Department of gastroenterology, Services hospital, Lahore. Period: January 2018 to January 2019. Material & Methods: Patients advance hepatitis genotype 3 infection was enrolled through non probability consecutive sampling technique. Main outcome variable is sustained virology response rate. SPSS version 23 was used for data analysis. Mean and standard deviation and frequency percentages were calculated for numerical and qualitative data respectively. P value ≤0.05 was considered as significant. Results: One way ANOVA was used to check the differences between four groups, while chi-square test was used for categorical variables. Overall SVR12 rates and causes of treatment failure for the primary (actual duration) for patients who received DCV+SOF for 24 weeks, overall SVR12 (mITT) was 64.4% with RBV and 11.9% without RBV and treatment failure was found 31.3% without RBV and 28.1% with RBV. Sensitivity analyses (duration initially considered), SVR12 in terms of mITT for 24 weeks treatment is 58.4% and without RBV and 15.6% with RBV. Treatment failure is 47.1% without and 23.5% with RBV. Conclusion: Daclatasvir with sofosbuvir is an effective treatment for hepatitis C genotype 3 infections as it achieved high sustained virology response rate in patients of advance liver disease or cirrhotic patients. Without addition of ribavirin this treatment is effective when given for 24 weeks. [ABSTRACT FROM AUTHOR]

An unprecedented spin cluster‐based network architecture {[NiII2(pdaa)(OH)2(H2O)]n (H2pdaa=1,4‐phenylene diacetic acid)}, comprising 1D linear chains of NiII ions crosslinked via Ni4O4 cubanes, forms under hydrothermal conditions; this 3D coordination network exhibits magnetic ordering at 23.9 K as well as a second magnetic ordering process at 2.8 K likely associated with a structural phase transition. [ABSTRACT FROM AUTHOR]