scholarly journals BANGO SEA XLOC/HMBC–H2OBC: complete heteronuclear correlation within minutes from one NMR pulse sequence

2019 ◽  
Vol 55 (81) ◽  
pp. 12208-12211
Author(s):  
Tamás Milán Nagy ◽  
Tamás Gyöngyösi ◽  
Katalin E. Kövér ◽  
Ole W. Sørensen
Keyword(s):  
Small Molecules ◽  
Time Scale ◽  
Pulse Sequence ◽  
Heteronuclear Correlation

Novel NMR experiments, BANGO SEA XLOC–H2OBC or BANGO HMBC–H2OBC, deliver complete heteronuclear correlations and assignments on a time scale of minutes on small molecules.

N.m.r. studies of red cells

1980 ◽  
Vol 289 (1037) ◽  
pp. 395-406 ◽  
Keyword(s):  
Small Molecules ◽  
Time Course ◽  
Pulse Sequence ◽  
Spin Echo ◽  
Cell System ◽  
Red Cells ◽  
Red Cell ◽  
Lactate And Pyruvate ◽  
Echo Pulse ◽  
2,3 Dpg

Recent n.m.r. studies of intact red cells are described. With 1 H n.m.r. the normal high resolution spectra of red cells, even at high fields, are relatively uninformative because the very large number of resonances from the cells merge into a broad envelope. If a simple 90- τ - 180° spin echo pulse sequence is used, however, many resonances can be resolved. These include signals from haemoglobin histidines, glutathione, lactate and pyruvate. 13 C and 31 P signals have also been seen with a spectrometer converted to observe these nuclei essentially simultaneously. N.m.r. is well suited to monitor the time course of events after a perturbation of the cell system. Lactate increase, glutathione recovery after oxidation and alkylation of glutathione by iodoacetate can all be observed directly in red cell suspensions by means of 1 H spin echo n.m.r. This method has also been used to measure isotope exchange ( 1 H - 2 H) of lactate and of pyruvate at both the C-3 and the C-2 positions, and some of these exchange rates can be interpreted in terms of the activity of specific enzymes in the cells. 1 H spin echo n.m.r. has also been used to obtain information about the transport rates of small molecules into cells. By means of the 13 C / 31 P spectrometer and [ 13 C-1] glucose, the 13 C enrichment of 2,3-diphosphoglycerate (2,3-DPG) can be monitored at the same time as the levels of 2,3-DPG, ATP and inorganic phosphate are observed by 31 P n.m.r.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

The E-ring: interactions with plasma and implications for its evolution

1984 ◽  
Vol 75 ◽  
pp. 599-602
Author(s):  
T.V. Johnson ◽  
G.E. Morfill ◽  
E. Grun
Keyword(s):  
Time Scale ◽  
Particle Density ◽  
High Energy ◽  
Particle Removal ◽  
Density Region ◽  
Drag Forces ◽  
Orbit Evolution ◽  
History Of ◽  
Ring Particle ◽  
Ring Material

A number of lines of evidence suggest that the particles making up the E-ring are small, on the order of a few microns or less in size (Terrile and Tokunaga, 1980, BAAS; Pang et al., 1982 Saturn meeting; Tucson, AZ). This suggests that a variety of electromagnetic and plasma affects may be important in considering the history of such particles. We have shown (Morfill et al., 1982, J. Geophys. Res., in press) that plasma drags forces from the corotating plasma will rapidly evolve E-ring particle orbits to increasing distance from Saturn until a point is reached where radiation drag forces acting to decrease orbital radius balance this outward acceleration. This occurs at approximately Rhea's orbit, although the exact value is subject to many uncertainties. The time scale for plasma drag to move particles from Enceladus' orbit to the outer E-ring is ~104yr. A variety of effects also act to remove particles, primarily sputtering by both high energy charged particles (Cheng et al., 1982, J. Geophys. Res., in press) and corotating plasma (Morfill et al., 1982). The time scale for sputtering away one micron particles is also short, 102 - 10 yrs. Thus the detailed particle density profile in the E-ring is set by a competition between orbit evolution and particle removal. The high density region near Enceladus' orbit may result from the sputtering yeild of corotating ions being less than unity at this radius (e.g. Eviatar et al., 1982, Saturn meeting). In any case, an active source of E-ring material is required if the feature is not very ephemeral - Enceladus itself, with its geologically recent surface, appears still to be the best candidate for the ultimate source of E-ring material.

Gap junctions in the prothoracic glands of the tobacco hornworm, Manduca sexta

1992 ◽  
Vol 50 (1) ◽  
pp. 706-707
Author(s):  
Ji-da Dai ◽  
M. Joseph Costello ◽  
Lawrence I. Gilbert
Keyword(s):  
Gap Junctions ◽  
Small Molecules ◽  
Manduca Sexta ◽  
Freeze Fracture ◽  
Cell Communication ◽  
Cellular Level ◽  
Thin Sections ◽  
Prothoracic Glands ◽  
Polyhydroxylated Steroids ◽  
Stimulation Of

Insect molting and metamorphosis are elicited by a class of polyhydroxylated steroids, ecdysteroids, that originate in the prothoracic glands (PGs). Prothoracicotropic hormone stimulation of steroidogenesis by the PGs at the cellular level involves both calcium and cAMP. Cell-to-cell communication mediated by gap junctions may play a key role in regulating signal transduction by controlling the transmission of small molecules and ions between adjacent cells. This is the first report of gap junctions in the PGs, the evidence obtained by means of SEM, thin sections and freeze-fracture replicas.

Fusion and Fission Processes in Exocytosis: Possible Roles for Synexin and Osmotic Lysis in the Two Events

1980 ◽  
Vol 38 ◽  
pp. 594-597
Author(s):  
H.B. Pollard ◽  
C.E. Creutz ◽  
C.J. Pazoles ◽  
J.H. Scott
Keyword(s):  
Small Molecules ◽  
Chromaffin Cells ◽  
Adrenal Glands ◽  
General Concept ◽  
Extracellular Calcium ◽  
Large Protein ◽  
Granule Membrane ◽  
Osmotic Lysis ◽  
Per Se ◽  
Chemical Evidence

Exocytosis is a general concept describing secretion of enzymes, hormones and transmitters that are otherwise sequestered in intracellular granules. Chemical evidence for this concept was first gathered from studies on chromaffin cells in perfused adrenal glands, in which it was found that granule contents, including both large protein and small molecules such as adrenaline and ATP, were released together while the granule membrane was retained in the cell. A number of exhaustive reviews of this early work have been published and are summarized in Reference 1. The critical experiments demonstrating the importance of extracellular calcium for exocytosis per se were also first performed in this system (2,3), further indicating the substantial service given by chromaffin cells to those interested in secretory phenomena over the years.

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