823 research outputs found
The relation of H2CO, 12CO, and 13CO in molecular clouds
Aims. We seek to understand how the 4.8 GHz formaldehyde absorption line is
distributed in the MON R2, S156, DR17/L906, and M17/M18 regions. More
specifically, we look for the relationship among the H2CO, 12CO, and 13CO
spectral lines. Methods. The four regions of MON R2 (60'x90'), S156 (5'0x70'),
DR17/L906 (40'x60'), and M17 /M18 (70'x80')were observed for H2CO (beam 10'),
H110a recombination (beam 10'), 6 cm continuum (beam 10'), 12CO (beam 1'), and
13CO (beam 1'). We compared the H2CO,12CO,13CO, and continuum distributions,
and also the spectra line parameters of H2CO,12CO, and 13CO. Column densities
of H2CO,13CO, and H2 were also estimated. Results. We found out that the H2CO
distribution is similar to the 12CO and the 13CO distributions on a large
scale. The correlation between the 13 CO and the H2CO distributions is better
than between the 12CO and H2CO distributions. The H2CO and the 13CO tracers
systematically provide consistent views of the dense regions. T heir maps have
similar shapes, sizes, peak positions, and molecular spectra and present
similar centr al velocities and line widths. Such good agreement indicates that
the H2CO and the 13CO arise from similar regions.Comment: 21 pages, 12 figures published, 201
IMass time: The future, in future!
Joseph John Thomson discovered and proved the existence of electrons through a series of experiments. His work earned him a Nobel Prize in 1906 and initiated the era of mass spectrometry (MS). In the intervening time, other researchers have also been awarded the Nobel Prize for significant advances in MS technology. The development of soft ionization techniques was central to the application of MS to large biological molecules and led to an unprecedented interest in the study of biomolecules such as proteins (proteomics), metabolites (metabolomics), carbohydrates (glycomics), and lipids (lipidomics), allowing a better understanding of the molecular underpinnings of health and disease. The interest in large molecules drove improvements in MS resolution and now the challenge is in data deconvolution, intelligent exploitation of heterogeneous data, and interpretation, all of which can be ameliorated with a proposed IMass technology. We define IMass as a combination of MS and artificial intelligence, with each performing a specific role. IMass will offer advantages such as improving speed, sensitivity, and analyses of large data that are presently not possible with MS alone. In this study, we present an overview of the MS considering historical perspectives and applications, challenges, as well as insightful highlights of IMass
Dimethyl 3,3′-diphenyl-2,2′-[(S)-thiophene-2,5-diylbis(carbonylazanediyl)]dipropanoate
The asymmetric unit of the title compound, C26H26N2O6S, contains two independent molecules; each has twofold symmetry with the S atom and the mid-point of the C—C bond of the thiophene ring located on a twofold rotation axis. In the two molecules, the terminal benzene rings are oriented at dihedral angles of 65.8 (3) and 63.5 (3)° with respect to the central thiophene rings. The methoxycarbonyl group of one molecule is disordered over two positions with site-occupancy factors of 0.277 (12) and 0.723 (12). Intermolecular N—H⋯O hydrogen bonding is present in the crystal structure
Application of Metabolomics in Traditional Chinese Medicine Differentiation of Deficiency and Excess Syndromes in Patients with Diabetes Mellitus
Metabolic profiling is widely used as a probe in diagnosing diseases. In this study, the metabolic profiling of urinary carbohydrates was investigated using gas chromatography/mass spectrometry (GC/MS) and multivariate statistical analysis. The kernel-based orthogonal projections to latent structures (K-OPLS) model were established and validated to distinguish between subjects with and without diabetes mellitus (DM). The model was combined with subwindow permutation analysis (SPA) in order to extract novel biomarker information. Furthermore, the K-OPLS model visually represented the alterations in urinary carbohydrate profiles of excess and deficiency syndromes in patients with diabetes. The combination of GC/MS and K-OPLS/SPA analysis allowed the urinary carbohydrate metabolic characterization of DM patients with different traditional Chinese medicine (TCM) syndromes, including biomarkers different from non-DM patients. The method presented in this study might be a complement or an alternative to TCM syndrome research
5-(Methoxycarbonyl)thiophene-2-carboxylic acid
In the title compound, C7H6O4S, a monoester derivative of 2,5-thiophenedicarboxylic acid, the carboxylic acid and the carboxylic acid ester groups are approximately coplanar with thiophene ring, making a dihedral angle of 3.1 (4) and 3.6 (4)°, respectively. In the crystal structure, molecules are connected by classical intermolecular O—H⋯O hydrogen bonds, forming centrosymmetric dimers
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