24,094 research outputs found
Sequence-specific double-strand cleavage of DNA by penta-N-methylpyrrolecarboxamide-EDTA·Fe(II)
In the presence of O2 and 5 mM dithiothreitol, penta-N-methylpyrrolecarboxamide-EDTA·Fe(II) [P5E·Fe(II)] at 0.5 µ M cleaves pBR322 plasmid DNA (50 µ M in base pairs) on opposite strands to afford discrete DNA fragments as analyzed by agarose gel electrophoresis. High-resolution denaturing gel electrophoresis of a 32P-end-labeled 517-base-pair restriction fragment containing a major cleavage site reveals that P5E·Fe(II) cleaves 3-5 base pairs contiguous to a 6-base-pair sequence, 5'-T-T-T-T-T-A-3' (4,323-4,328 base pairs). The major binding orientation of the pentapeptide occurs with the amino terminus at the adenine side of this sequence. In the presence of 5 mM dithiothreitol, 0.01 µ M P5E·Fe(II) converts form I pBR322 DNA at 0.22 µ M plasmid (1.0 mM in base pairs) to 40% form II, indicating the cleavage reaction is catalytic, turning over a minimum of nine times. This synthetic molecule achieves double-strand cleavage of DNA (pH 7.9, 25 degrees C) at the 6-base-pair recognition level and may provide an approach to the design of "artificial restriction enzymes.
Analytical comparisons of ablative nozzle materials final report, jun. 20, 1963 - nov. 20, 1964
Reaction kinetics ablation program to predict ablation performance of rocket nozzle heat protection material
Some taste substances are direct activators of G-proteins
Amphiphilic substances may stimulate cellular events through direct activation of G-proteins. The present experiments indicate that several amphiphilic sweeteners and the bitter tastant, quinine, activate transducin and Gi/Go-proteins. Concentrations of taste substances required to activate G-proteins in vitro correlated with those used to elicit taste. These data support the hypothesis that amphiphilic taste substances may elicit taste through direct activation of G-proteins
Breakdown of self-similarity at the crests of large amplitude standing water waves
We study the limiting behavior of large-amplitude standing waves on deep
water using high-resolution numerical simulations in double and quadruple
precision. While periodic traveling waves approach Stokes's sharply crested
extreme wave in an asymptotically self-similar manner, we find that standing
waves behave differently. Instead of sharpening to a corner or cusp as
previously conjectured, the crest tip develops a variety of oscillatory
structures. This causes the bifurcation curve that parametrizes these waves to
fragment into disjoint branches corresponding to the different oscillation
patterns that occur. In many cases, a vertical jet of fluid pushes these
structures upward, leading to wave profiles commonly seen in wave tank
experiments. Thus, we observe a rich array of dynamic behavior at small length
scales in a regime previously thought to be self-similar.Comment: 4 pages, 5 figures. Final version accepted for publicatio
Combustion of coal gas fuels in a staged combustor
Gaseous fuels produced from coal resources generally have heating values much lower than natural gas; the low heating value could result in unstable or inefficient combustion. Coal gas fuels may contain ammonia which if oxidized in an uncontrolled manner could result in unacceptable nitrogen oxide exhaust emission levels. Previous investigations indicate that staged, rich-lean combustion represents a desirable approach to achieve stable, efficient, low nitrogen oxide emission operation for coal-derived liquid fuels contaning up to 0.8-wt pct nitrogen. An experimental program was conducted to determine whether this fuel tolerance can be extended to include coal-derived gaseous fuels. The results of tests with three nitrogen-free fuels having heating values of 100, 250, and 350 Btu/scf and a 250 Btu/scf heating value doped to contain 0.7 pct ammonia are presented
Ocean shrimp report 1979 season
Statewide Pacific ocean shrimp, Pandalus jordani, landings
totaled 2,237.7 mt (4,922,857 lb), down 3,745 mt
(8,240,386 lb) from the 1978 catch of 5,983.3 mt
(13,163,243 lb). The 1979 landings are the lowest
since 1976 when 1,545.5 mt (3,400,191 lb) were landed. Area A (Eureka-Crescent City)landings dropped to 1,842.5 mt (4,053,605 lb) from 5,046.3 mt (11,101,895 lb) landed during the previous season. No landings were made in Area B-1 (Fort Bragg). Only 2.0 mt (4,385 lb) were reported caught in Area B-2 (Bodega Bay). Record landings of 393.1 mt
(864,867 lb) were made in Area C (Morro Bay-Avila), surpassing the previous record of 90.4 mt (199,000 lb) landed in 1953. In Area A a record 71 vessels, 34 double-rigged and 37 single-rigged, shrimped during the
season. Average catch per hour was a low .15 mt (338 lb) and .22 mt (490 1b) for single-rig and double-rig vessels, respectively. In Area C average catch per hour was .23 mt (508 lb) and .42 mt (924 lb) for single-rig and double-rig
vessels, respectively. Area A shrimp catches were dominated by 1-year-old shrimp throughout most of the season. The
age composition in Area C shifted predominately from 2-year-old shrimp in May and June to predominately 1-year-old shrimp in July, August, October, and November. Area A was closed for one month from July 15 to
August 15 because closure criteria of less than .16 mt
(350 lb) per hour for two consecutive weeks was met and year class composition exceeded 70% of 1-year-old shrimp. The season was closed October 14 when the catch per hour criterion was exceeded again. (18pp.
Sanctioning Defendants\u27 Non-Willful Delay:The Failure of Rule 55 and a Proposal for its Reform
For as long as parties have pursued claims through litigation, those against whom claims are asserted have delayed the litigation process. Defendants, and other parties against whom claims are asserted, (hereinafter collectively referred to as defendants), fail to answer complaints against them in time; they delay in responding to discovery requests, motions and court orders, and they fail to appear for trials and other proceedings
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