First direct mass measurement of the neutron-deficient nucleusAl24

2015 ◽  
Vol 92 (4) ◽  
Author(s):  
U. Chowdhury ◽  
K. G. Leach ◽  
C. Andreoiu ◽  
A. Bader ◽  
M. Brodeur ◽  
...  
Keyword(s):  
Mass Measurement ◽  
Direct Mass Measurement

scholarly journals Direct mass measurement of bare short-lived 44V, 48Mn, 41Ti and 45Cr ions with isochronous mass spectrometry

2004 ◽  
Vol 586 (1-2) ◽  
pp. 27-33 ◽  
Author(s):  
J Stadlmann ◽  
M Hausmann ◽  
F Attallah ◽  
K Beckert ◽  
P Beller ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Measurement ◽  
Direct Mass Measurement ◽  
Isochronous Mass Spectrometry

scholarly journals First Direct Mass Measurement of the Two-Neutron Halo NucleusHe6and Improved Mass for the Four-Neutron HaloHe8

2012 ◽  
Vol 108 (5) ◽  
Author(s):  
M. Brodeur ◽  
T. Brunner ◽  
C. Champagne ◽  
S. Ettenauer ◽  
M. J. Smith ◽  
...  
Keyword(s):  
Mass Measurement ◽  
Neutron Halo ◽  
Direct Mass Measurement

Direct Mass Measurement of the Four-Neutron Halo NuclideHe8

2008 ◽  
Vol 101 (1) ◽  
Author(s):  
V. L. Ryjkov ◽  
M. Brodeur ◽  
T. Brunner ◽  
M. Smith ◽  
R. Ringle ◽  
...  
Keyword(s):  
Mass Measurement ◽  
Neutron Halo ◽  
Direct Mass Measurement

Direct mass measurement ofN∼Znuclei withA= 64–80 using the CSS2 cyclotron

2005 ◽  
Vol 31 (10) ◽  
pp. S1771-S1774 ◽  
Author(s):  
M Chartier ◽  
M B Gómez Hornillos ◽  
W Mittig ◽  
A Lépine-Szily ◽  
L Caballero Ontanaya ◽  
...  
Keyword(s):  
Mass Measurement ◽  
Direct Mass Measurement

scholarly journals Mass spectrometric characterization of nicked fragments of the β-subunit of human chorionic gonadotropin

1997 ◽  
Vol 43 (7) ◽  
pp. 1172-1181 ◽  
Author(s):  
Chuanliang Liu ◽  
Larry D Bowers
Keyword(s):  
Mass Measurement ◽  
Human Leukocyte ◽  
Mass Determination ◽  
Β Subunit ◽  
Leukocyte Elastase ◽  
Human Leukocyte Elastase ◽  
Direct Mass Measurement ◽  
Oligosaccharide Structures

Abstract We describe the use of an HPLC/MS technique for the characterization of nicked fragments of hCG β-subunit. After reductive alkylation of the nicked hCG β-subunit with vinylpyridine, endoproteinase Glu-C or trypsin was used to digest the protein to produce peptides that could be analyzed by HPLC/electrospray ionization MS. Human leukocyte elastase digestion was used to produce an experimentally nicked hCG. Two nicking sites were observed, between amino acids 42Thr and 43Arg and between 44Val and45Leu. The former site has not been previously reported for elastase digestion. The structures of the fragments were confirmed by HPLC/MS after removal of the oligosaccharide by direct mass measurement and by mass determination of their proteolytic digests. Without the glycopeptidase treatment, the microheterogeneity of the two N-linked oligosaccharides could be deduced from the spectra of the proteolytic fragments. Nicking with elastase was found to alter the oligosaccharide structures. Nicked β-subunit samples isolated from the urine of choriocarcinoma patients were also analyzed and the location of the nicking site(s) agreed with that determined by classical techniques. Important differences in the oligosaccharide structures were also observed in these samples, including the presence of triantennary oligosaccharides not found in hCG from healthy subjects. These findings demonstrate the potential of HPLC/MS for characterization of glycoprotein standard preparations.

STRUCTURE OF THE DRIP LINE NUCLEI PROBED BY SEPARATION ENERGIES

2006 ◽  
Vol 15 (07) ◽  
pp. 1471-1475 ◽  
Author(s):  
ZDENĚK DLOUHÝ
Keyword(s):  
Mass Measurement ◽  
Drip Line ◽  
Magic Numbers ◽  
Neutron Halo ◽  
Rich Region ◽  
Direct Mass Measurement ◽  
First Time

The derivation of two-neutron separation energies from the direct mass measurement of the neutron-rich nuclei at GANIL has enabled us to establish new neutron magic numbers N=6 and 16 in neutron-rich region for the first time instead of normal 8 and 20 and to confirm the existence of new doubly magic nuclei 8 He and 24 O . Adjunction of a proton to the new doubly magic nuclei 8 He and 24 O enable to accept two or more neutrons by these nuclei and form, respectively, the neutron halo 11 Li nucleus and create a very neutron-rich set of 27,29,31 F isotopes. The connection between doubly magic nuclei and the neutron halo and/or very neutron-rich odd-Z nuclei is studied by analysis of triton separation energies St of light neutron-rich nuclei.

Conformation of eukaryotic ribosomal RNAs

1983 ◽  
Vol 41 ◽  
pp. 592-593
Author(s):  
M. Boublik ◽  
G. Thornton ◽  
G. Oostergetel ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
Molecular Weight ◽  
Mass Measurement ◽  
Carbon Film ◽  
Structural Complexity ◽  
Scanning Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Pure Nitrogen ◽  
Freeze Dried ◽  
Scanning Transmission ◽  
Partially Unfolded

Understanding the structural complexity of ribosomes and their role in protein synthesis requires knowledge of the conformation of their components - rRNAs and proteins. Application of dedicated scanning transmission electron microscope (STEM), electrical discharge of the support carbon film in an atmosphere of pure nitrogen, and determination of the molecular weight of individual rRNAs enabled us to obtain high resolution electron microscopic images of unstained freeze-dried rRNA molecules from BHK cells in a form suitable for evaluation of their 3-D structure. Preliminary values for the molecular weight of 28S RNA from the large and 18S RNA from the small ribosomal subunits as obtained by mass measurement were 1.84 x 106 and 0.97 x 106, respectively. Conformation of rRNAs consists, in general, of alternating segments of intramolecular hairpin stems and single stranded loops in a proportion which depends on their ionic environment, the Mg++ concentration in particular. Molecules of 28S RNA (Fig. 1) and 18S RNA (not shown) obtained by freeze-drying from a solution of 60 mM NH+4 acetate and 2 mM Mg++ acetate, pH 7, appear as partially unfolded coils with compact cores suggesting a high degree of ordered secondary structure.

Detection and identification of Catalpol metabolites in the rat plasma, urine and faeces using ultra-high performance liquid chromatography-Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry

2020 ◽  
Vol 21 ◽  
Author(s):  
Zedong Xiang ◽  
Shaoping Wang ◽  
Haoran Li ◽  
Pingping Dong ◽  
Fan Dong ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Performance ◽  
Mass Measurement ◽  
Neutral Loss ◽  
Rat Plasma ◽  
Accurate Mass ◽  
Chromatographic Retention ◽  
Rat Urine ◽  
Q Exactive

Background:: Catalpol, an iridoid glycoside, is one of the richest bioactive components present in Rehmannia glutinosa. More and more metabolites of drugs have exhibit various pharmacological effects, thus providing guidance for clinical application. However, few researches have paid attention on the metabolism of catalpol. Objective:: This study aimed to establish a rapid and effective method to identify catalpol metabolites and evaluate the biotransformation pathways of catalpol in rats. Methods:: In this study, catalpol metabolites in rat urine, plasma and faeces were analyzed by UHPLC-Q-Exactive MS for the characterization of metabolism of catalpol. Based on high-resolution extracted ion chromatograms (HREICs) and parallel reaction monitoring mode (PRM), metabolites of catalpol were identified by comparing the diagnostic product ions (DPIs), chromatographic retention times, neutral loss fragments (NLFs) and accurate mass measurement with those of catalpol reference standard. Results: A total of 29 catalpol metabolites were detected and identified in both negative and positive ion modes. Nine metabolic reactions including deglycosylation, hydroxylation, dihydroxylation, hydrogenation, dehydrogenation, oxidation of methylene to ketone, glucuronidation, glycine conjugation and cysteine conjugation were proposed. Conclusion:: A rapid and effective method based on UHPLC-Q-Exactive MS was developed to mine the metabolism information of catalpol. Results of metabolites and biotransformation pathways of catalpol suggested that when orally administrated, catalpol was firstly metabolized into catalpol aglycone, after which phase Ⅰ and phase Ⅱ reactions occurred. However, hydrophilic chromatography-mass spectrometry still needed to further find the polar metabolites of catalpol.

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