Measurement and Prediction of the Elongational Stress Growth in a Dilute Solution of DNA Molecules

P. Sunthar; Duc At Nguyen; Roelf Dubbelboer; J. Ravi Prakash; Tam Sridhar

doi:10.1021/ma0511907

Measurement and Prediction of the Elongational Stress Growth in a Dilute Solution of DNA Molecules

Macromolecules ◽

10.1021/ma0511907 ◽

2005 ◽

Vol 38 (24) ◽

pp. 10200-10209 ◽

Cited By ~ 16

Author(s):

P. Sunthar ◽

Duc At Nguyen ◽

Roelf Dubbelboer ◽

J. Ravi Prakash ◽

Tam Sridhar

Keyword(s):

Dilute Solution ◽

Dna Molecules ◽

Stress Growth ◽

Elongational Stress

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The non-isothermal rheological behaviour of molten polymers: Shear and elongational stress growth of polyisobutylene under heating

Rheologica Acta ◽

10.1007/bf01503266 ◽

1981 ◽

Vol 20 (5) ◽

pp. 458-462 ◽

Cited By ~ 5

Author(s):

F. P. La Mantia ◽

G. Titomanlio ◽

D. Acierno

Keyword(s):

Rheological Behaviour ◽

Stress Growth ◽

Molten Polymers ◽

Elongational Stress

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Replication of Bacteriophage 186 DNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009422x ◽

1972 ◽

Vol 30 ◽

pp. 194-195

Author(s):

Dhruba K. Chattoraj ◽

Ross B. Inman

Keyword(s):

Electron Microscopy ◽

Dna Replication ◽

Frame Of Reference ◽

Dna Molecules ◽

E Coli ◽

Phage Dna ◽

Partial Denaturation

Electron microscopy of replicating intermediates has been quite useful in understanding the mechanism of DNA replication in DNA molecules of bacteriophage, mitochondria and plasmids. The use of partial denaturation mapping has made the tool more powerful by providing a frame of reference by which the position of the replicating forks in bacteriophage DNA can be determined on the circular replicating molecules. This provided an easy means to find the origin and direction of replication in λ and P2 phage DNA molecules. DNA of temperate E. coli phage 186 was found to have an unique denaturation map and encouraged us to look into its mode of replication.

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Computer averaging of lattice images of poly-4-methyl-pentene-1 (P4mp1): Noise created artifacts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126731 ◽

1987 ◽

Vol 45 ◽

pp. 388-389

Author(s):

P. Pradère ◽

J.F. Revol ◽

R. St. John Manley

Keyword(s):

Low Dose ◽

Polymer Concentration ◽

Processing System ◽

Limiting Factor ◽

Dilute Solution ◽

New Techniques ◽

Dose Unit ◽

Lattice Images ◽

Dose Imaging ◽

Imaging Conditions

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.

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Synchrony of Digestion of SV40 DNA by Exonuclease III Determined by EM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116991 ◽

1975 ◽

Vol 33 ◽

pp. 674-675

Author(s):

Ray Wu ◽

G. Ruben ◽

B. Siegel ◽

P. Spielman ◽

E. Jay

Keyword(s):

Dark Field ◽

Uranyl Acetate ◽

Enzyme Digestion ◽

Dna Molecules ◽

Exonuclease Iii ◽

Aluminum Films ◽

Double Stranded Dna ◽

Before And After ◽

Exo Iii ◽

Sv40 Dna

A method for determining long nucleotide sequences of double-stranded DNA is being developed. It involves (a) the synchronous digestion of the DNA from the 3' ends with EL coli exonuclease III (Exo III) followed by (b) resynthesis with labeled nucleotides and DNA polymerase. A crucial factor in the success of this method is the degree to which the enzyme digestion proceeds synchronously under proper conditions of incubation (step a). Dark field EM is used to obtain accurate measurements on the lengths and distribution of the DNA molecules before and after digestion with Exo III, while gel electrophoresis is used in parallel to obtain a mean length for these molecules. It is the measurements on a large enough sample of individual molecules by EM that provides the information on how synchronously the digestion proceeds. For length measurements, the DNA molecules were picked up on 20-30 Å thick carbon-aluminum films, using the aqueous Kleinschmidt technique and stained with 7.5 x 10-5M uranyl acetate in 90% ethanol for 3 minutes.

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Two-stage self-seeding method for preparation of single crystals of poly(phenylene sulfide)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153816 ◽

1989 ◽

Vol 47 ◽

pp. 368-369

Author(s):

Sengshiu Chung ◽

Peggy Cebe

Keyword(s):

Single Crystals ◽

High Performance ◽

Dilute Solution ◽

Two Stage ◽

Annealing Behavior ◽

High Performance Polymers ◽

Seeding Method ◽

Phenylene Sulfide

We are studying the crystallization and annealing behavior of high performance polymers, like poly(p-pheny1ene sulfide) PPS, and poly-(etheretherketone), PEEK. Our purpose is to determine whether PPS, which is similar in many ways to PEEK, undergoes reorganization during annealing. In an effort to address the issue of reorganization, we are studying solution grown single crystals of PPS as model materials.Observation of solution grown PPS crystals has been reported. Even from dilute solution, embrionic spherulites and aggregates were formed. We observe that these morphologies result when solutions containing uncrystallized polymer are cooled. To obtain samples of uniform single crystals, we have used two-stage self seeding and solution replacement techniques.

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