Social influences related to college students’ use of Macintosh computers on an all-PC campus

In the present qualitative research study, 35 Mac users were interviewed in a university campus that exclusively supports PC machines. We particularly explored the Mac-users’ social influences, saving technological and other influences for future reports. Results showed Mac users to possess significant connections with other Mac users on the university campus. The Mac users in our study indicated that positive, past exposure, including Apple’s advertising of Macs, had sharp influences on their decisions to become and remain Mac users.     

Calculating fragment impact velocity from penetration data

Depth of penetration experiments were conducted with fragment simulating projectiles launched into Celotex^® in order to develop an equation for the strike velocity as a function of the FSP mass and the depth of penetration into Celotex^® recovery media. A powder gun launched FSPs, designed in accordance with STANAG-2920 [NATO STANAG-2920 Ballistic Test Method for Personal Armour Materials and Combat Clothing, 2nd ed., 1999.] weighing between 0.13 g and 53.78 g at striking velocities between 198 m/s and 1524 m/s. A multiple linear regression analysis was used to determine an empirical relationship for the strike velocity to the impact parameters of depth of penetration, fragment mass, and mean presented area. Sabot launched natural fragments weighing between 2.8 g and 15.8 g at striking velocities between 532 m/s and 1084 m/s were used to validate the equation.     

Long RT-PCR Amplification of the entire coding sequence of the polycystic kidney disease 1 (PKD1) gene

The peptidoglycan cortex of endospores of Bacillus species is required for maintenance of spore dehydration and dormancy, and the structure of the cortex may also allow it to function in attainment of spore core dehydration. A significant difference between spore and growing cell peptidoglycan structure is the low degree of peptide cross-linking in cortical peptidoglycan; regulation of the degree of this cross-linking is exerted by D,D-carboxypeptidases. We report here the construction of mutant B. subtilis strains lacking all combinations of two and three of the four apparent D, D-carboxypeptidases encoded within the genome and the analysis of spore phenotypic properties and peptidoglycan structure for these strains. The data indicate that while the dacA and dacC products have no significant role in spore peptidoglycan formation, the dacB and dacF products both function in regulating the degree of cross-linking of spore peptidoglycan. The spore peptidoglycan of a dacB dacF double mutant was very highly cross-linked, and this structural modification resulted in a failure to achieve normal spore core dehydration and a decrease in spore heat resistance. A model for the specific roles of DacB and DacF in spore peptidoglycan synthesis is proposed.     

High temperature superconductivity applied to electric motors

The application of high temperature superconductors to electric motors is discussed. Both the advantages and limitations of using superconductors in motors are reviewed. A synchronous motor with a high-temperature superconductor field winding for pump and fan drive applications is described and some of its unique features are identified. A 10000-hp superconducting motor design and its advantages in terms of improved efficiency and reduced size are described. The performance requirements for the superconducting wire necessary for motor applications are considered, and the progress being made toward realizing these requirements is assessed     

A controlled trial of venlafaxine in trichotillomania: interim phase I results

Vibrio vulnificus, a particularly virulent halophilic vibrio, has been isolated from the blood and skin necrotic lesion of a hemodialyzed patient with sepsis. The patient has had exposure of the skin to seawater. Various chronic conditions including renal failure have a great risk for developing septicemia due to V vulnificus. It is necessary to inform persons with liver diseases or immunocompromising conditions of hazards associated with the consumption of undercooked seafood and seawater exposure.     

Mathematical models for motile bacterial transport in cylindrical tubes

Mathematical models considering motile bacterial transport within a geometrically restrictive cylindrical tube were developed. Two macroscopic transport parameters, the random motility coefficient as a self-diffusion coefficient of the cell population and the chemotactic velocity as a chemical-induced velocity, were derived. The three-dimensional cell balance equation was reduced to forms similar to Segel's one-dimensional phenomenological cell balance equations with additional modifications for bacteria-wall interactions. Two conceptually different approaches accounting for such interactions were presented. The first approach parallels treatments in the gas kinetic theory by viewing bacterial interactions with walls as collisions and subsequent diffusive/specular reflections, which led to the Bosanquet formula for the bacterial diffusion coefficient. Based on the experimental observation that bacterial swimming motion is guided by a straight tube, the second approach considered modifications in the bacterial swimming orientation as a consequence of various long-range interactions with the tube surface. A phenomenological turning model capable of aligning bacterial motion along a tube axis was proposed. The model predicts that under the geometrical restriction of a small cylindrical tube, the macroscopic bacterial transport resulting from the proposed turning model can exhibit behavior that ranges from dimensionally reduced diffusion to pure wave propagation, depending on the influence of the tube diameter on the reversal probability in the bacterial swimming motion. Our theoretical model provides explicit equations that explain how such a transition can occur. The predicted results were then qualitatively compared with experimental data from the literature. As a preliminary comparison, we concluded that bacterial transport in cylindrical tubes of diameter 10 micrometers remains in the mode of a dimensionally reduced diffusion, and shifts to a wave motion when the tube diameter decreases to 6 micrometers.