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1.
J Phys Chem A ; 123(22): 4750-4754, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31074982

RESUMO

The 1-methylvinoxy radical (1-MVO) is an important intermediate in the combustion and tropospheric reaction of OH. However, the vibrational structures of this species and its anionic form, 1-methylvinoxide anion (1-MVO-), are not fully known. Thus, in this study, we obtained the infrared (IR) absorption spectra of 1-MVO and 1-MVO- trapped in a solid Ar matrix. 1-MVO- anions were produced by electron bombardment during matrix deposition of Ar containing a small amount of acetone. The anions were destroyed upon irradiation at 675, 365, and 160 nm, although the formation of 1-MVO was only observed upon irradiation at 675 nm. The assignment of the IR bands of 1-MVO- and 1-MVO was based on the expected chemistry upon photoexcitation and comparison of line wavenumbers, relative IR intensities, and D-isotopic shift ratios with those predicted at the B3LYP/aug-cc-pVTZ level of theory.

2.
Sci Rep ; 8(1): 14392, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30258064

RESUMO

The direct infrared (IR) absorption spectra of propargyl cations were recorded. These cations were generated via the electron bombardment of a propyne/Ar matrix sample during matrix deposition. Secondary photolysis with selected ultraviolet (UV) light was used for grouping the observed bands of various products. The band assignment of the propargyl cation in solid Ar was performed according by referring to the previous infrared photodissociation (IRPD) and velocity-map imaging photoelectron (VMI-PE) data, and via theoretical predictions of the anharmonic vibrational wavenumbers, band intensities, and deuterium-substituted isotopic ratios. Almost all the IR active bands with an observable intensity were recorded and the ν11 mode was reported for the first time.

3.
Genetics ; 209(1): 105-113, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29545466

RESUMO

A properly designed distance-based measure can capture informative genetic differences among individuals with different phenotypes and can be used to detect variants responsible for the phenotypes. To detect associated variants, various tests have been designed to contrast genetic dissimilarity or similarity scores of certain subject groups in different ways, among which the most widely used strategy is to quantify the difference between the within-group genetic dissimilarity/similarity (i.e., case-case and control-control similarities) and the between-group dissimilarity/similarity (i.e., case-control similarities). While it has been noted that for common variants, the within-group and the between-group measures should all be included; in this work, we show that for rare variants, comparison based on the two within-group measures can more effectively quantify the genetic difference between cases and controls. The between-group measure tends to overlap with one of the two within-group measures for rare variants, although such overlap is not present for common variants. Consequently, a dissimilarity or similarity test that includes the between-group information tends to attenuate the association signals and leads to power loss. Based on these findings, we propose a dissimilarity test that compares the degree of SNP dissimilarity within cases to that within controls to better characterize the difference between two disease phenotypes. We provide the statistical properties, asymptotic distribution, and computation details for a small sample size of the proposed test. We use simulated and real sequence data to assess the performance of the proposed test, comparing it with other rare-variant methods including those similarity-based tests that use both within-group and between-group information. As similarity-based approaches serve as one of the dominating approaches in rare-variant analysis, our results provide some insight for the effective detection of rare variants.


Assuntos
Estudos de Associação Genética , Variação Genética , Modelos Genéticos , Modelos Estatísticos , Algoritmos , Estudos de Casos e Controles , Simulação por Computador , Estudos de Associação Genética/métodos , Humanos , Fenótipo , Tamanho da Amostra
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