39 research outputs found
Two-Year Outcomes After Minimally Invasive Surfactant Therapy in Preterm Infants: Follow-Up of the OPTIMIST-A Randomized Clinical Trial
Importance: The long-term effects of surfactant administration via a thin catheter (minimally invasive surfactant therapy [MIST]) in preterm infants with respiratory distress syndrome remain to be definitively clarified. /
Objective: To examine the effect of MIST on death or neurodevelopmental disability (NDD) at 2 years' corrected age.
/ Design, Setting, and Participants: Follow-up study of a randomized clinical trial with blinding of clinicians and outcome assessors conducted in 33 tertiary-level neonatal intensive care units in 11 countries. The trial included 486 infants with a gestational age of 25 to 28 weeks supported with continuous positive airway pressure (CPAP). Collection of follow-up data at 2 years' corrected age was completed on December 9, 2022.
/ Interventions: Infants assigned to MIST (n = 242) received exogenous surfactant (200 mg/kg poractant alfa) via a thin catheter; those assigned to the control group (n = 244) received sham treatment.
/ Main Outcomes and Measures: The key secondary outcome of death or moderate to severe NDD was assessed at 2 years' corrected age. Other secondary outcomes included components of this composite outcome, as well as hospitalizations for respiratory illness and parent-reported wheezing or breathing difficulty in the first 2 years.
/ Results: Among the 486 infants randomized, 453 had follow-up data available (median gestation, 27.3 weeks; 228 females [50.3%]); data on the key secondary outcome were available in 434 infants. Death or NDD occurred in 78 infants (36.3%) in the MIST group and 79 (36.1%) in the control group (risk difference, 0% [95% CI, -7.6% to 7.7%]; relative risk [RR], 1.0 [95% CI, 0.81-1.24]); components of this outcome did not differ significantly between groups. Secondary respiratory outcomes favored the MIST group. Hospitalization with respiratory illness occurred in 49 infants (25.1%) in the MIST group vs 78 (38.2%) in the control group (RR, 0.66 [95% CI, 0.54-0.81]) and parent-reported wheezing or breathing difficulty in 73 (40.6%) vs 104 (53.6%), respectively (RR, 0.76 [95% CI, 0.63-0.90]).
/ Conclusions and Relevance: In this follow-up study of a randomized clinical trial of preterm infants with respiratory distress syndrome supported with CPAP, MIST compared with sham treatment did not reduce the incidence of death or NDD by 2 years of age. However, infants who received MIST had lower rates of adverse respiratory outcomes during their first 2 years of life.
/ Trial Registration: anzctr.org.au Identifier: ACTRN12611000916943
La<sub>(l-x)</sub>A<sub>x</sub>Mn<sub>(l-y)</sub>B<sub>y</sub>O<sub>3</sub> supported on honeycomb substrate -Characterization and application for catalytic converter
1833-1839Perovskite catalysts are reported as
substitute to noble-metal catalysts for automobile catalytic converter. The low
surface area and non-compatibility with alumina wash coat had been the major
problems for limiting the application of perovskite for auto-exhaust treatment.
La0.7Sr0.3Mn0.95Pt0.05O3
supported on alumina washcoated honeycomb substrate has been prepared in this
study. The detail characterization, at each step of preparation of catalyst
coated substrate, using techniques such as BET SA, porosity, pore size
distribution, TGA and XRD have been carried out and discussed. Characterization
results reveal the possible use of supported perovskite for automobile exhaust
treatment
Nitric oxide absorption by hydrogen peroxide in airlift reactor: a study using response surface methodology
Absorption of nitric oxide from nitric oxide /air mixture in hydrogen peroxide solution has been studied on bench scale internal loop airlift reactor. The objective of this investigation was to study the performance of nitric oxide absorption in hydrogen peroxide solution in the airlift reactor and to explore/determine the optimum conditions using response surface methodology. A Box–Behnken model has been employed as an experimental design. The effect of three independent variables—namely nitric oxide gas velocity, 0.02–0.11 m/s; nitric oxide gas concentration, 300–3,000 ppm and hydrogen peroxide concentration, 0.25–2.5 %—has been studied on the absorption of nitric oxide in aqueous hydrogen peroxide in the semi-batch mode of experiments. The optimal conditions for parameters were found to be nitric oxide gas velocity, 0.02 m/s; nitric oxide gas concentration, 2,246 ppm and hydrogen peroxide concentration, 2.1 %. Under these conditions, the experimental nitric oxide absorption efficiency was observed to be *65 %. The proposed model equation using response surface methodology has shown good agreement with the experimental data, with a correlation coefficient (R2) of 0.983. The results showed that optimised conditions could be used for the efficient absorption of nitric oxide in the flue gas emanating from industries
Alumina supported, perovskite oxide based catalytic materials and their auto-exhaust application
Substituted lanthanum manganate type perovskites have been synthesized following co-precipitation and a modified in
situ method. These perovskites have been supported on cordierite honeycomb with and without alumina washcoat. Alumina
washcoated supports with lanthana pre-coat, have been found suitable for the in situ synthesis of perovskites to avoid reactivity
of perovskite precursors with alumina (in absence of lanthana pre-coat). This modified synthesis has resulted in remarkable
improvement in surface area while, excellent catalyst adhesion has also been observed. The catalyst composition has also
been promoted by a small amount of platinum, which has resulted in improved catalytic activity. These catalysts have been
first evaluated using a pure gas laboratory evaluation assembly. Catalysts prepared on alumina washcoated honeycomb having
lanthana pre-coat, shows better activity than the samples prepared by co-precipitation method. Catalytic converter prototypes
have been prepared using the selected catalyst and evaluated on engine and chassis dynamometers. The converter shows
good conversion activity for all the three pollutants, viz. CO, HC and NOx . These results substantiate the possibility of using
supported perovskites for automobile applications. The detailed characterization of supported perovskites, however, could
not be done conclusively and demand for further investigations, to properly understand the interaction of pre-coat, alumina
washcoat and catalyst
Application of supported perovskite-type catalysts for vehicular emission control
Catalytic control of auto-exhaust emissions is one of the most successful applications of heterogeneous catalysis, both in
commercial and environmental point of views. Although noble metal-based catalysts have dominated this area, efforts were always
put in towards development of low cost non-noble metal-based catalysts. With the recent need of closed-coupled catalytic
converter, thermal stability requirements have also become more severe, leading to the search for stable catalytic materials. Mixed
oxides, including those perovskite type compounds with ABO3 structure have been extensively studied, mainly for their catalytic
and electrical properties. Low surface area of these catalysts has so far been the most important limitation for their catalytic
applications involving high space velocities, e.g. auto-exhaust catalysis. Various synthesis routes have been earlier attempted to
improve their surface area, yet this was much inferior than the noble metal catalysts, dispersed on high surface area alumina. The in
situ synthesis of these oxides on alumina is often associated with the formation of undesired phases, due to the reactive nature of
perovskite precursors. However, alumina washcoat, commonly used for improving the surface area of ceramic and metallic catalyst
supports, can be modified for perovskite applications. In situ synthesis of stabilized perovskites on modified alumina-washcoated
supports offer high surface area and excellent catalyst adhesion. Although, it is difficult to ascertain the presence of pure perovskite
type materials on support, such improved synthesis has resulted in remarkable improvement in their catalytic activity for their
applications in auto-exhaust catalytic converters. This review presents our work on synthesis of various improved perovskite-type
mixed oxides supported on modified alumina-washcoated cordierite honeycomb, their characterization, and detailed catalytic
evaluations for possible application in automobile pollution control
Monoethanol Amine Modified Zeolite 13X for CO2 Adsorption at Different Temperatures
Zeolite 13X has been modified with monoethanol amine (MEA). MEA loadings of 0.5–25 wt % have been
achieved using the impregnation method in different solvents. The mode of incorporation based on methanol
with stirring at room temperature appears to be the most feasible. The adsorbent has been characterized for
crystallinity, surface area, pore volume, and pore size. The thermal stability of the adsorbent is studied using
a thermal analyzer. The CO2 adsorption capacity of adsorbents is evaluated using the breakthrough adsorption
method with a packed column on a 10 g scale. The adsorption capacities of adsorbents are estimated in the
temperature range 30–120 °C. The adsorbents show improvement in CO2 adsorption capacity over the unmodified
zeolite by a factor of ca. 1.6 at 30 °C, whereas at 120 °C the efficiency improved by a factor of 3.5. For
adsorption at these temperatures, different MEA loading levels were found to be suitable as per the governing
adsorption phenomena, that is, physical or chemical. The adsorbent is also studied for CO2 selectivity over N2
at 75 °C. The MEA-modified adsorbent shows better CO2 selectivity, which was improved further in the
presence of moisture