ABSTRACT
Finding the active center in a bimetallic zeolite imidazolate framework (ZIF) is highly crucial for the electrocatalytic oxygen evolution reaction (OER). In the present study, we constructed a bimetallic ZIF system with cobalt and manganese metal ions and subjected it to an electrospinning technique for feasible fiber formation. The obtained nanofibers delivered a lower overpotential value of 302 mV at a benchmarking current density of 10 mA cm-2 in an electrocatalytic OER study under alkaline conditions. The obtained Tafel slope and charge-transfer resistance values were 125 mV dec-1 and 4 Ω, respectively. The kinetics of the reaction is mainly attributed from the ratio of metals (Co and Mn) present in the catalyst. Jahn-Teller distortion reveals that the electrocatalytic active center on the Mn-incorporated ZIF-67 nanofibers (Mn-ZIF-67-NFs) was found to be Mn3+ along with the Mn2+ and Co2+ ions on the octahedral and tetrahedral sites, respectively, where Co2+ ions tend to suppress the distortion, which is well supported by density functional theory analysis, molecular orbital study, and magnetic studies.
ABSTRACT
AIMS: We are reporting single-institution's experience regarding the role of conservative management in 38 cases of minor and major anastomotic leaks [AL] occurring after primary surgery of esophageal atresia [EA] with tracheo-esophageal fistula [TEF] during last 17 years between 2000 and 2017. In this retrospective review, we are sharing our experience and protocol of management of AL with more emphasis to evaluate: (a) role of conservative treatment in major AL (b) role of extra-pleural approach in enhancing the success rate in conservative treatment in major AL (c) to define the criteria for major & minor leaks and (d) to evaluate the role of ventilation in primary EA surgery to control AL. METHODS: All these cases were operated through extra-pleural approach and out of total 203 cases, 38[18.7%] developed anastomotic leaks. In 29 of the 38 cases [14.3%], leak was minor and in 9 cases [4.4%] the leak was a major one. All these cases of leaks were managed conservatively. RESULTS: All cases of major and minor leaks showed spontaneous healing except one case of minor leak that died before healing due to major cardiac anomaly. For minor leaks, average healing time was 9.5 days while for major leaks it was 17.4 days. Overall mortality was 14.8% and there was no mortality directly attributable to major or minor leak. During follow up, the incidence of stricture was 40% in cases having anastomotic leaks, while in cases without a leak, the incidence of stricture was 23.3%. These all cases of stricture responded to regular dilatations. CONCLUSION: We believe in cases of major AL, where primary repair is done by EP approach, a conservative treatment should be the treatment of choice. With this conservative approach of management of major AL, we not only save the native esophagus, the best conduit, but there is also less morbidity and mortality.
ABSTRACT
Spray drying had been used to synthesize silica-carbon black nanocomposite micrometric granules with a uniform distribution of the two components. This was achieved by hindering the preferential diffusion of hydrophobic carbon and hydrophilic silica particles in the water droplets during evaporative assembly by introducing gum arabic as a stabilizing agent and network former. Both positive and negatively charged silica nanoparticles were used to check the stability of the sol and its effect on the morphology of the spray dried granules. X-ray and neutron scattering, complemented with electron microscopy, were used to investigate the correlation and distribution of the nanoparticles within the granules. Porous silica granules, having surface area of 157â¯m2/g, were obtained after removal of carbon black by calcination. An environment-friendly solar absorbing coating had been prepared using as synthesized granules.
