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Objective: To compare the effectiveness of early high-flow nasal cannula (HFNC) and low-flow oxygen support (LFOS) in children under 5 years with acute hypoxemic respiratory failure (AHRF) due to severe community-acquired pneumonia in low-middle-income countries. Methods: An open-label randomized clinical trial enrolled children aged 2-59 months with AHRF due to severe community-acquired pneumonia and randomized into HFNC and LFOS. In the LFOS group, the patient received cold wall oxygen humidified by bubbling through sterile water administered through simple nasal prongs at a fixed flow rate of 2 L/min. In the HFNC group, the patient received humidified, heated (37 °C), high-flow oxygen at a flow rate assigned based on weight range, with a titratable oxygen fraction. The primary outcome was treatment failure in 72 h (escalating the respiratory support method using any modality other than primary intervention). Results: Data was analyzed intention-to-treat (HFNC = 124; LFOS = 120). Median (IQR) age was 12 (6-20) and 11 (6-27) months, respectively. Treatment failure occurred in a significantly lower proportion in the HFNC group (7.3%, n = 9/124) as compared to the LFOS group (20%, n = 24/120) (relative risk = 0.36, 95% CI 0.18 to 0.75; p = 0.004; adjusted hazard ratio 0.34, 95% CI 0.16 to 0.73; p = 0.006). The intubation rate was significantly lower in the HFNC group (7.3%, n = 9/124 vs. 16.7%, n = 20/120; relative risk = 0.44, 95% CI 0.21 to 0.92, p = 0.023). There were no significant differences noted in other secondary outcomes. No mortality occurred. Conclusion: High-flow nasal cannula oxygen therapy used as early respiratory support in children under 5 years with acute hypoxemic respiratory failure due to severe community-acquired pneumonia was associated with significantly lower treatment failure compared with standard low-flow oxygen support. Trial registration: CTRI/2016/04/006788. Registered 01 April 2016, https://ctri.nic.in/Clinicaltrials/advsearch.php. Supplementary Information: The online version contains supplementary material available at 10.1007/s44253-024-00031-8.
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Pyrolysis of lignocellulosic biomass and waste plastics has been intensely studied in the last few decades to obtain renewable fuels and chemicals. Various pyrolysis devices have been developed for use in a laboratory setting, operated either in batch or continuously at scales ranging from milligrams per hour to tenths of g per hour. We report here the design and operation of a novel staged free-fall (catalytic) pyrolysis unit and demonstrate that the concept works very well for the (catalytic) pyrolysis of pinewood sawdust, paper sludge, and polypropylene as representative feeds. The unit consists of a vertical tube with a pretreatment section, a pyrolysis section, a solid residue collection section, a gas-liquid separation/collection section, and a catalytic reaction section to optionally perform ex situ catalytic upgrading of the pyrolysis vapor. The sample is placed in a tube, which is transported by gravity through various sections of the unit. It allows for rapid testing with semicontinuous feeding (e.g., 50 g h-1) and the opportunity to perform reactions under an (inert) gas (e.g., N2) at atmospheric as well as elevated pressure (e.g., 50 bar). Liquid yields for noncatalytic sawdust pyrolysis at optimized conditions (475 °C and atmospheric pressure) were 63 wt % on biomass intake. A lower yield of 51 wt % (on a biomass basis) was obtained for the noncatalytic pyrolysis of paper sludge, likely due to the presence of minerals (e.g., CaCO3) in the feed. The possibility of using the unit for ex situ catalytic pyrolysis (pyrolysis at 475 °C and catalytic upgrading at 550 °C) was also successfully demonstrated using paper sludge as the feed and H-ZSM-5 as the catalyst (21 wt % catalyst on biomass). This resulted in a biphasic liquid product with 25.6 wt % of an aqueous phase and 11 wt % of an oil phase. The yield of benzene, toluene, and xylenes was 1.9 wt % (on a biomass basis). Finally, the concept was also proven for a representative polyolefin (polypropylene), both noncatalytic as well as in situ catalytic pyrolysis using H-ZSM-5 as the catalyst at 500 °C. The liquid yield of thermal, noncatalytic plastic pyrolysis was as high as 77 wt % on plastic intake, while in situ catalytic pyrolysis gave a combined 7.8 wt % yield of benzene, toluene, and xylenes on plastic intake.
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The thermochemical decomposition of woody biomass has been widely identified as a promising route to produce renewable biofuels. More recently, the use of molten salts in combination with pyrolysis has gathered increased interest. The molten salts may act as a solvent, a heat transfer medium, and possibly also a catalyst. In this study, we report experimental studies on a process to convert woody biomass to a liquid hydrocarbon product with a very low oxygen content using molten salt pyrolysis (350-450 °C and atmospheric pressure) followed by subsequent catalytic conversions of the liquids obtained by pyrolysis. Pyrolysis of woody biomass in molten salt (ZnCl2/NaCl/KCl with a molar composition of 60:20:20) resulted in a liquid yield of 46 wt % at a temperature of 450 °C and a molten salt/biomass ratio of 10:1 (mass). The liquids are highly enriched in furfural (13 wt %) and acetic acid (14 wt %). To reduce complexity and experimental issues related to the production of sufficient amounts of pyrolysis oils for further catalytic upgrading, model studies were performed to convert both compounds to hydrocarbons using a three-step catalytic approach, viz., (i) ketonization of acetic acid to acetone, (ii) cross-aldol condensation between acetone and furfural to C8-C13 products, followed by (iii) a two-stage catalytic hydrotreatment of the latter to liquid hydrocarbons. Ketonization of acetic acid to acetone was studied in a continuous setup over a ceria-zirconia-based catalyst at 250 °C. The catalyst showed no signs of deactivation over a period of 230 h while also achieving high selectivity toward acetone. Furfural was shown to have a negative effect on the catalyst performance, and as such, a separation step is required after pyrolysis to obtain an acetic-acid-enriched fraction. The cross-aldol condensation reaction between acetone and furfural was studied in a batch using a commercial Mg/Al hydrotalcite as the catalyst. Furfural was quantitatively converted with over 90% molar selectivity toward condensed products with a carbon number between C8 and C13. The two-stage hydrotreatment of the condensed product consisted of a stabilization step using a Ni-based Picula catalyst and a further deep hydrotreatment over a NiMo catalyst, in both batch setups. The final product with a residual 1.5 wt % O is rich in (cyclo)alkanes and aromatic hydrocarbons. The overall carbon yield for the four-step approach, from pinewood biomass to middle distillates, is 21%, assuming that separation of furfural and acetic acid after the pyrolysis step can be performed without losses.
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OBJECTIVES: To determine whether levetiracetam is an alternative to fosphenytoin to control Benzodiazepine Refractory Status Epilepticus (BRSE) in pediatric population and also to compare the acute drug related side-effects and ventilation requirement among the both arms of anti-epileptic drug therapy. METHODS: All consecutive children admitted with BRSE were randomized to group A, who received fosphenytoin at 20 mg/kg phenytoin equivalents (PE) dose and group B who received levetiracetam at 40 mg/kg over 10 min. Time to terminate seizure (response latency) was measured. If seizure remained refractory after 20 min of test drug administration, appropriate drug escalation was made according to pediatrician's discretion. All primary and secondary outcome measures were compared between the two therapeutic groups. RESULTS: Of 61 children enrolled over 18 mo period, 29 (47.5%) were randomized to group A and 32 (52.5%) were randomized to Group B. Baseline characteristics were comparable between the two groups. Among 61 children, 58(98%) required Pediatric Intensive Care Unit (PICU) admission and among those 5(8.2%) children required mechanical ventilation. Duration of PICU stay, hospital stay, the response latency and seizure recurrence were compared between both groups. Significant number of children received additional anti-epileptic drugs (AEDs) in fosphenytoin group [9/29(31%)] compared to levetiracetam group [2/32(7%)] to control seizure. CONCLUSIONS: Levetiracetam may be an effective alternative to fosphenytoin in management of BRSE in children but multicentric trials with large sample size are needed to substantiate this observation.