First-Person Authority

Review ofHave I Reasons: Work and Writ- ings, 1993–2007 by Robert Morris. Edited and introduced by Nena Tsouti-Schillinger. (Durham, NC: Duke University Press, 2008. Pp. 273. $84.95 cloth;$23.95 paper.

Role of local electrostatic fields in protein-protein and protein-solvent interactions determined by vibrational Stark effect spectroscopy

textThis examines the interplay of structure and local electrostatic fields in protein-protein and protein-solvent interactions. The partial charges of the protein amino acids and the polarization of the surrounding solvent create a complex system of electrostatic fields at protein-protein and protein-solvent interfaces. An approach incorporating vibrational Stark effect (VSE) spectroscopy, dissociation constant measurements, and molecular dynamics (MD) simulations was used to investigate the electrostatic interactions in these interfaces. Proteins p21Ras (Ras) and Rap1A (Rap) have nearly identical amino acid sequences and structures along the effector-binding region but bind with different affinities to Ral guanine nucleotide dissociation stimulator (RalGDS). A charge reversion mutation at position 31 alters the binding affinity of Ras and Rap with RalGDS from 0.1 [mu]M and 1 [mu]M, to 1 [mu]M and 0.5 [mu]M, respectively. A spectral probe was placed at various locations along the binding interface on the surface of RalGDS as it was docked with Ras and Rap single (position 30 or 31) and double mutants (both positions). By comparing the probes' absorption energies with the respective wild-type (WT) analogs, VSE spectroscopy was able to measure molecular-level electrostatic events across the protein-protein interface. MD simulations provided a basis for deconvoluting the structural and electrostatic changes observed by the probes. The mutation at position 31 was found to be responsible for both structural and electrostatic changes compared to the WT analogs. Furthermore, previous identification of positions N27 and N29 on RalGDS as "hot spots" that help discriminate between structurally similar GTPases was supported. The RalGDS probe-containing variants and three model compounds were placed in aqueous solvents with varying dielectric constants to measure changes in absorption energy. We investigated the ability of the Onsager solvent model to describe the solvent induced changes in absorption energy, while MD simulations were employed to determine the location and solvation of the probes at the protein-solvent interface. The solvent accessible-surface area, a measure of hydration, was determined to correlate well with the change in magnitude of the probe's absorption energy and the displaced solvent by the probe.Chemistr

Factors affecting the development in culture and the pathogenicity of Septoria glycines Hemmi

Brown spot, caused by Septoria glycines Hemmi, is one of the most destructive diseases of soybeans in Tennessee. The objectives of this study were to (a) evaluate the effect of temperature, humidity, precipitation, and age of the host plant upon infection of soybean leaves by S. glycines and (b) determine the resistance of eight soybean cultivars to the pathogen. The optimum temperature for linear growth and sporulation of S. glycines on potato-dextrose agar and V-8 juice agar was 24 to 28 C. Czapek-Dox agar was not a satisfactory medium for growth and sporula-tion. Atomizing a suspension of S. glycines pycnidiospores upon the soybean leaves was the most effective method of inoculation in controlled-temperature chambers. Distributing a spore or mycelial suspension over the leaves with a glass rod did not result in brown spot symptoms. Disease incidence was low in all experiments with the effect of temperature on infection. There was no significant difference among the four temperatures. Disease incidence of soybeans inoculated at 29 C day - 25 C night was significantly higher in a growth chamber containing a cool-moisture humidifier than in a chamber with ambient humidity. Brown spot symptoms of soybeans in the field were rated weekly during the summer of 1978. The two major increases in symptoms occurred in late June and in late August and September. Each increase occurred 10 to 18 days after a period with relative humidity of 90% or higher for at least 18 hours and two consecutive days with one inch or more of precipitation. Monitoring spore release with a Kramer-Collins spore sampler was of little use in predicting an increase in symptoms, as only four S. glycines pycnidiospores were collected in 1741 hours of sampling. There were no significant differences in disease severity in eight soybean cultivars inoculated in the greenhouse. However, signifi-cant differences occurred among disease severity in the same eight cultivars when detached leaves were inoculated. Brown spot symptoms developed on detached leaves of Essex, Lee 74, and York, but did not develop on Bedford, Centennial, Dare, Forrest, or Pickett 71. Additional monitoring of brown spot symptoms in the field is necessary to confirm the effect of temperature, precipitation, and humidity on the development of brown spot. Results of detached leaf inoculations should be compared with field inoculations to assess the reliability of this method of determining resistance to brown spot

The Vehicle, February 1960, Vol. 2 no. 1

Vol. 2, No. 1 Table of Contents Editorialpage 2 A White Man\u27s BurdenRobert Mills Frenchpage 4 Passing TrainWayne Bakerpage 8 AutumnMajor Dan Ragainpage 8 Chaos in CulturevilleJ.B. Youngpage 9 Cure-allJerry N. Whitepage 13 Love-Long DistanceMary Ellen Mockbeepage 13 Metropolitan CaravanThomas McPeakpage 14 Ode to the Lion HuntersRichard Blairpage 16 ImmortalityM.E.M.page 16 EntranceSam Martinpage 16https://thekeep.eiu.edu/vehicle/1006/thumbnail.jp

The Vehicle, February 1960, Vol. 2 no. 1

Vol. 2, No. 1 Table of Contents Editorialpage 2 A White Man\u27s BurdenRobert Mills Frenchpage 4 Passing TrainWayne Bakerpage 8 AutumnMajor Dan Ragainpage 8 Chaos in CulturevilleJ.B. Youngpage 9 Cure-allJerry N. Whitepage 13 Love-Long DistanceMary Ellen Mockbeepage 13 Metropolitan CaravanThomas McPeakpage 14 Ode to the Lion HuntersRichard Blairpage 16 ImmortalityM.E.M.page 16 EntranceSam Martinpage 16https://thekeep.eiu.edu/vehicle/1006/thumbnail.jp

Experimental hydrophilic vinyl polysiloxane (VPS) impression materials incorporating a novel surfactant compared with commercial VPS

This PhD was partially funded by National University of Sciences & Technology (NUST), Islamabad, Pakistan, and therefore we thank the authorities at NUST