Spectroscopic Studies of Internal Injector Deposits (IDID) Resulting from the Use of Non-Commercial Low Molecular Weight Polyisobutylenesuccinimide (PIBSI)

2014 ◽  
Vol 7 (3) ◽  
pp. 762-770 ◽  
Author(s):  
Jim Barker ◽  
Jacqueline Reid ◽  
Colin Snape ◽  
David Scurr ◽  
William Meredith
Keyword(s):  
Molecular Weight ◽  
Spectroscopic Studies ◽  
Low Molecular Weight

Carbon-13 Resonance Spectroscopic Studies on the Formation of Borate and Diphenylborinate Complexes of Polyhydroxy Compounds

1973 ◽  
Vol 51 (19) ◽  
pp. 3277-3286 ◽  
Author(s):  
Philip A. J. Gorin ◽  
Mytosk Mazurek
Keyword(s):  
Molecular Weight ◽  
Magnetic Resonance ◽  
Spectroscopic Studies ◽  
Sodium Tetraborate ◽  
Low Molecular Weight ◽  
Hydroxyl Groups ◽  
Polyhydroxy Compounds ◽  
Borate Complex ◽  
Equilibrium Reactions ◽  
Borate Complexes

On complexing with sodium tetraborate the 13C magnetic resonance (c.m.r.) spectra of certain sugars contain considerably broadened signals. Replacement of the reagent with sodium diphenylborinate resulted in spectra with sharp singlets corresponding to the diphenylborinate complex, indicating that 13C-11B coupling likely does not occur. Most of the broadening is due rather to either the presence of more than one conformer of the borate complex or the rapid interconversion of the compound with borate complexes of types II and III. In one group of experiments the complexing of diphenylborinate with several low molecular weight sugars and polysaccharides was followed through c.m.r. spectroscopy. In another, complexing was observed with pyranosides having 1,3-hydroxyl groups with orientations that were almost diaxial. In the equilibrium reactions the approximate extent of complexing was estimated and with compounds that can form more than one complex, such as glycerol, the number and structures of the complexes were determined.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment
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