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Full-Text Articles in Biophysics
Electron Shock Waves, Frances Terry, Mostafa Hemmati
Electron Shock Waves, Frances Terry, Mostafa Hemmati
Journal of the Arkansas Academy of Science
No abstract provided.
Rotational Symmetries Of Nuclear States: Spin Determinations In Advanced Laboratory, Wilfred J. Braithwaite
Rotational Symmetries Of Nuclear States: Spin Determinations In Advanced Laboratory, Wilfred J. Braithwaite
Journal of the Arkansas Academy of Science
An advanced laboratory experiment is described which shows the connection between the rotational symmetries of nuclear states and the assignments of spins to discrete nuclear states. Standard angular correlation methods were used to study the two sequential gamma ray transitions in each ⁶⁰Ni nucleus, populated by unobserved beta decays from a weak radioactive ⁶⁰Co source. The chosen electronics and detectors were inexpensive and easy to operate. This experiment was extended to introduce students to real-world data acquisition, using finite-geometry detectors, which resulted in enormously larger coincident data rates.
Conformational And Circular Dichroism Studies On N-Acetyl-L-Prolyl-D-Alanyl-Methylamide, S. Ramaprasad
Conformational And Circular Dichroism Studies On N-Acetyl-L-Prolyl-D-Alanyl-Methylamide, S. Ramaprasad
Journal of the Arkansas Academy of Science
The compact ordered conformations of the molecule N-Acteyl-L-Prolyl-D-Alanyl-Methylamide have been studied by semiempirical energy calculations in vacuum and circular dichroism (CD) in solution. The presence of ordered structure has been observed in hydrogen bond promoting solvents like trifluoroethanol by CD studies. In hydrogen bond breaking solvents, like trifluoroacetic acid (TFA), significant fraction of the ordered conformers probably assume extended conformation without intramolecular hydrogen bonds and perhaps are in equilibrium with the fraction of compact ordered structures. The trend observed in going from nonpolar to polar solvent is also compatible with the previous NMR studies in solution. The semiempirical energy calculations …
Plasma Corticosterone Levels In Cholesterol-Fed Cockerels Before And After A Twenty Minute Run, Stanley N. David, Clarene L. David
Plasma Corticosterone Levels In Cholesterol-Fed Cockerels Before And After A Twenty Minute Run, Stanley N. David, Clarene L. David
Journal of the Arkansas Academy of Science
Cockerels were exercised to observe the influence of physical activity on plasma corticosterone concentrations. The birds were maintained on a commercial mash or on an atherogenic diet. Plasmas were collected on the first day, fifteen days after the first collection and immediately after a 20 minute run on that fifteenth day. The plasma corticosterone levels as determined by radioimmunoassay showed extreme variations within collections. Hence, the data analysis indicated no significant changes of the Compound β in the blood of the cockerels due to diet, or exercise or the combination of both. The causes for the wide variation of plasma …
Concanavalin A-Nonbinding Enzymes Of Crotalus Scutulatus Scutulatus Venom, C. K. Childs, Michael W. Hinson, Dewey H. Sifford, Bob D. Johnson
Concanavalin A-Nonbinding Enzymes Of Crotalus Scutulatus Scutulatus Venom, C. K. Childs, Michael W. Hinson, Dewey H. Sifford, Bob D. Johnson
Journal of the Arkansas Academy of Science
Crotalus scutulatus scutulatus crude venom was separated into two fractions by Concanavalin A Sepharose 4B affinity chromatography. The Concanavalin A-nonbinding fraction (F-l) exhibited phosphomonoesterase (orthophosphoric monoester phosphohydrolase EC 3.1 .3.2), phosphodiesterase, 5 '-nucleotidase (5 '-ribonucleotide phosphohydrolase EC 3.1.3.5), phospholipase A (phosphatidate 2-acylhydrolase EC 3.1.1.4), hyaluronidase (hyaluronate glycanohydrolase EC 3.2.1.d), N-benzoyl-Larginine ethyl esterase, p-toluenesulfonyl-L-arginine methyl esterase, L-amino acid oxidase (L-amino acid: O2 oxidoreductase [deaminating] EC 1.4.3.2), and caseinolytic activities. Thrombin-like and NAD nucleosidase (5 '-ribonudeotide phosphohydrolase EC 3.1.3.5) activities were not observed. DEAE Sephadex A-50 ion exchange chromatography by two stage elution of F-l yielded several fractions having proteinase activities. Proteinase …
Role Of Centriolar Matrix And Striated Rootlets In Centriolar Pairing And Orientation During Spermatogenesis In Hydractina Echinata, Maurice G. Kleve
Role Of Centriolar Matrix And Striated Rootlets In Centriolar Pairing And Orientation During Spermatogenesis In Hydractina Echinata, Maurice G. Kleve
Journal of the Arkansas Academy of Science
Transmission electron microscopy of the spermatogenic stages of the hydroid, Hydractinia echinata, reveals a series of complex structural and positional changes in the centrioles of spermatocytes and spermatids. The newly generated centriolar pairs of spermatocytes form an unusual four-centriole aggregate that persists until cell division. The distal centrioles of this aggregate are shrouded with a very dense matrix that accumulates after centriolar replication. This matrix facilitates the mechanical attachment between distal centrioles and microtubular nucleating satellites, striated rootlets and pericentriolar processes. The association of these accessory structures occurs sequentially and is repeated in spermatocytes and spermatids. An electron dense plaque, …
Repair Of Lethal Damage Induced In A Hamster X Amphibian Hybrid Tissue Culture Cell Line By Ultraviolet Light And Gamma Ray, Susan Kulp, Ann Page, H. Gaston Griggs
Repair Of Lethal Damage Induced In A Hamster X Amphibian Hybrid Tissue Culture Cell Line By Ultraviolet Light And Gamma Ray, Susan Kulp, Ann Page, H. Gaston Griggs
Journal of the Arkansas Academy of Science
A hybrid cell line was formed by fusing cells from two established vertebrate tissue culture cell lines (V79B1 hamster and A84 Xenopus), which were known to differ substantially in resistance to some radiation-induced lesions and in associated repair potential. Ultraviolet and gamma ray dose-survival relations were then determined and analyzed for the three cell lines, primarily to compare the radiosensitivity (Do dose) of the hybrid line with that of each parental line for each radiation. Further experimentation was conducted to determine the extent to which observed differences in these Do doses could be attributed to interactions of the combined parental …
Effects Of Gamma Radiation On Salix Nigra Marsh Cuttings, Roy Z. Gehring
Effects Of Gamma Radiation On Salix Nigra Marsh Cuttings, Roy Z. Gehring
Journal of the Arkansas Academy of Science
Dormant cuttings of Salix nigra Marsh, were exposed to gamma radiation from a cobalt-60 source at a dose rate of 1110 roentgens (r) per minute. Exposure doses ranged from 50 r through 100 Kr with 100% mortality at 10 Kr. Low doses of ionizing radiation apparently stimulated growth, while higher doses progressively retarded growth. The growth of the staminate catkins was inversely proportional to total exposure dose (increased dose resulted in progressively decreased growth). Determination of growth rates at different intervals post-irradiation indicated recovery of the surviving fraction of the irradiated cuttings. At ninety days, the highest growth rate occurred …
Computer Pattern Recognition Of Action Potentials, Ronald S. Remmel
Computer Pattern Recognition Of Action Potentials, Ronald S. Remmel
Journal of the Arkansas Academy of Science
A general method of pattern recognition was applied to the problem of recognizing extracellularly-recorded neuronal action potentials in the presence of noise and other pulses. A PDP1 1/23 performed the calculations. There were four stages: 1.) A bandpass filter attenuated noises; 2.) the data input program digitized the signal every 55 μsec. If the signal exceeded a threshold, 12 samples of the signal and the time were written onto the disk; 3.) the pulse discriminating program recognized an action potential by fitting the 12 points with this function: v(t) = (a + bt + ct² ) exp(-t/Ƭ). For each pulse …
Rapid Electroosmosis Measurements, James O. Wear
Rapid Electroosmosis Measurements, James O. Wear
Journal of the Arkansas Academy of Science
A cell has been designed and built that allows for rapid measurement of volume moved in a definite time by electroosmosis. The cell is simple to use and is not very elaborate. Using a water jacket, the cell temperature can be controlled to ± 0.1° C. Measurements are presented for acetonitrile, dimethylformamide, and nitrobenzene at 25° C for applied voltages of 25, 50, 75, and 100 volts.