Diethyl carbonate (DEC) is an attractive biofuel that can be used to displace petroleum-derived diesel fuel, thereby reducing CO 2 and particulate emissions from diesel engines. A better understanding of DEC combustion characteristics is needed to facilitate its use in internal combustion engines. Towards this goal, ignition delay times for DEC were measured at conditions relevant to internal combustion engines using a rapid compression machine (RCM) and a shock tube. The experimental conditions investigated covered a wide range of temperatures (660-1300 K), a pressure of 30 bar, and equivalence ratios of 0.5, 1.0 and 2.0 in air.To provide further understanding of the intermediates formed in DEC oxidation, species concentrations were measured in a jet-stirred reactor at 10 atm over a temperature range of 500-1200 K and at equivalence ratios of 0.5, 1.0 and 2.0. These experimental measurements were used to aid the development and validation of a chemical kinetic model for DEC.The experimental results for ignition in the RCM showed near negative temperature coefficient (NTC) behavior. Six-membered alkylperoxy radical (R 2 ) isomerizations are conventionally thought to initiate low-temperature branching reactions responsible for NTC behavior, but DEC has no such possible 6-and 7-membered ring isomerizations. However, its molecular structure allows for 5-, 8-and 9-membered ring R 2 isomerizations. To provide accurate rate constants for these ring structures, ab initio computations for R 2 QOOH isomerization reactions were performed. These new R 2 isomerization rate constants have been implemented in a chemical kinetic model for DEC oxidation. The model simulations have been compared with ignition delay times measured in the RCM near the NTC region. Results of the 3 simulation were also compared with experimental results for ignition in the high-temperature region and for species concentrations in the jet-stirred reactor. Chemical kinetic insights into the oxidation of DEC were made using these experimental and modeling results.
Classical homocystinuria is due to cystathionine b-synthase (CBS) deficiency. More than 130 mutations, which differ in prevalence and severity, have been described at the CBS gene. Mutation p.I278T is very prevalent, has been found in all European countries where it has been looked for with the exception of the Iberian peninsula, and is known to respond to vitamin B 6 . On the other hand, mutation p.T191M is prevalent in Spain and Portugal and does not respond to B 6 . We analysed 30 pedigrees from Spain, Portugal, Colombia and Argentina, segregating for homocystinuria. The p.T191M mutation was detected in patients from all four countries and was particularly prevalent in Colombia. The number of p.T191M alleles described in this study, together with those previously published, is 71. The prevalence of p.T191M among CBS mutant alleles in the different countries was: 0.75 in Colombia, 0.52 in Spain, 0.33 in Portugal, 0.25 in Venezuela, 0.20 in Argentina and 0.14 in Brazil. Haplotype analyses suggested a double origin for this mutation. No genotype-phenotype correlation other than the B 6 -nonresponsiveness could be established for the p.T191M mutation. Additionally, three new mutations, p.M173V, p.I429del and c.69_70+8del10, were found. The
In this article, one of the novel mutations, c.208_209+ 8del10, was incorrectly given as c.69_70+8del10. It corresponds to patient 64 in Table 4. Additionally, the genotype for patient 34 (Table 4) is p.T191M/p.T191M, and not p.[T191M;D444N]/ [T191M;D444N]. Accordingly, in the Discussion, the two sentences: ''It should be noted that two patients in our series bore p.D444N: patient #54 (described above) and patient #34. The latter was homozygous for the
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.