7,149 research outputs found
An Inquiry into the Cause of the Increase of Tuberculosis of Swine
The great increase in the number of swine found to be tuberculous presented a problem, the solution of which appeared to be desirable before adequate control measures could be devised or recommended. In the hope that a solution of the problem may be found this station undertook an investigation and attempted by experimental inquiry to determine the infection type of the tuberculosis associated with the animals which constituted the bulk of the retentions. In view of the apparent increased incidence and spread of tuberculosis among poultry in a large hog raising section, of which Nebraska forms a part, the experimental project mentioned was to a large extent so directed as to prove or disprove the hypothesis that avian infection may at least in part be held accountable for the great morbidity rate for tuberculosis among swine and its marked increase during the last fifteen years
The Immunizing Value of Commercial Vaccines and Bacterins Against Hemorrhagic Septicemia
In the course of certain studies having to do with hemorrhagic septicemia, we were particularly struck with the difficulties which we encountered in the immunization of susceptible laboratory animals (rabbits). This difficulty in no small degree excited our curiosity regarding the immunizing value of the considerable number of Hemorrhagic Septicemia bacterins and vaccines which during recent years have become such a prominent article of commerce. In the hope of securing some information relative to the immunizing value of the agents mentioned, we undertook a series of experiments in which the immunity of the bacterin and vaccine injected laboratory animals was definitely tested by subsequent inoculations with B. bipolaris
The Incidence of Avian Tuberculosis in Mammals other than Swine
The recognition of a very widespread and intense distribution of avian tuberculosis on the farms of a wide area of the United States, as well as the involvement of a mammalian species also, brought to the foreground the question whether or not the great prevalence of poultry tuberculosis could be of importance also from a public health point of view. This phase of the problem not only pertains to the people on the farms but likewise is of fundamental importance to the consumers of poultry produce. European authors had already identified the avian tubercle bacillus in human lesions while in this country careless speakers outside the profession of medicine and irresponsible journalists had made more or less sensational statements on the subject. The alleged public health phase of avian tuberculosis was regarded as warrant for an attempt to acquire more definite information on this subject. The importance of the problem arising from the widespread distribution of avian tuberculosis and its demonstrated communicability to at least one mammalian species of economic importance justified an extension of the investigation and hence the Nebraska Agricultural Experiment Station undertook the inquiry, the results of which are set forth in the following account
The Value of Commercial Vaccines and Bacterins Against Fowl Cholera
A great prevalence of the disease known as fowl cholera has naturally stimulated an interest in possible means of prevention and especially in those which may bring about a more or less lasting immunity. Vaccines which were favorably reported by some failed utterly in the hands of others, so that on the whole no substantial advantage has been gained. Vaccines and bacterins are nevertheless constantly urged on poultry owners confronted with disease and the Experiment Station is frequently called upon to give an opinion on their value or to recommend any special preparation. In order to comply with those demands in an intelligent and impartial manner, we have thought it wise to make some experiments with the various preparations offered by the pharmaceutical trade in the hope that this may enable us to recommend all or any preparation for the relief of our poultry raisers
Proteochemometric modeling of HIV protease susceptibility
<p>Abstract</p> <p>Background</p> <p>A major obstacle in treatment of HIV is the ability of the virus to mutate rapidly into drug-resistant variants. A method for predicting the susceptibility of mutated HIV strains to antiviral agents would provide substantial clinical benefit as well as facilitate the development of new candidate drugs. Therefore, we used proteochemometrics to model the susceptibility of HIV to protease inhibitors in current use, utilizing descriptions of the physico-chemical properties of mutated HIV proteases and 3D structural property descriptions for the protease inhibitors. The descriptions were correlated to the susceptibility data of 828 unique HIV protease variants for seven protease inhibitors in current use; the data set comprised 4792 protease-inhibitor combinations.</p> <p>Results</p> <p>The model provided excellent predictability (<it>R</it><sup>2 </sup>= 0.92, <it>Q</it><sup>2 </sup>= 0.87) and identified general and specific features of drug resistance. The model's predictive ability was verified by external prediction in which the susceptibilities to each one of the seven inhibitors were omitted from the data set, one inhibitor at a time, and the data for the six remaining compounds were used to create new models. This analysis showed that the over all predictive ability for the omitted inhibitors was <it>Q</it><sup>2 </sup><sub><it>inhibitors </it></sub>= 0.72.</p> <p>Conclusion</p> <p>Our results show that a proteochemometric approach can provide generalized susceptibility predictions for new inhibitors. Our proteochemometric model can directly analyze inhibitor-protease interactions and facilitate treatment selection based on viral genotype. The model is available for public use, and is located at HIV Drug Research Centre.</p
On the Effectiveness of Dry Film Lubricant Coatings in Reducing Automotive Valve Train Wear
The effect of three dry lubricants on automotive valve train wear resistance was studied experimentally. Scuffing wear occurs as the cam slides across the lifter face where the rotating motion of the camshaft is converted into the linear motion necessary to drive the cylinder head valves. This scuffing is caused by localized microscopic bonding between the skidding surfaces. It can be minimized by using dry film lubricant coatings to increase the boundary lubrication depth adjacent to the contact area. To compare valve train wear resistance in the laboratory, rotating cam lobes coated with dry lubricants--parkerization, spray-applied graphite coating, and brush-applied molybdenum disulfide coating-were pressed against valve lifters that were constrained in a fixture. The brush-applied molybdenum disulfide coating was the most effective of the three tested lubricants in reducing scuffing wear
Integration and Operation of an Electrically Small Magnetic EZ Antenna With a High-Power Standing Wave Oscillator Source
© 2015 IEEE. The efficacy of the three-dimensional, rectangular magnetic EZ antenna for use with mesoband high-power microwave (HPM) sources has been demonstrated previously. It overcomes the typical bulky and massive impedance-matching components found currently in most HPM systems, making it an attractive option when space is very limited. However, its extremely compact nature presents practical challenges when dealing with extremely high-power sources due to the associated local field enhancements near the feed and the near-field resonant parasitic element. This letter presents a fully integrated, high-voltage source and radiating system that has several improvements in the antenna, source, and power system that have not before been demonstrated. The full system includes a ferroelectric generator, standing wave oscillator source, and electrically small antenna (ka = 0.37) operating at 510 MHz that can be packaged inside a 15-cm-diameter tube. This small diameter results in a quarter-wavelength-diameter ground plane, and the effects of this small ground plane on the radiation characteristics are explored. The development of a pressurized radome allows for operation at 73.6 kV, significantly higher than previous studies
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Precipitation regime change in Western North America: The role of Atmospheric Rivers.
Daily precipitation in California has been projected to become less frequent even as precipitation extremes intensify, leading to uncertainty in the overall response to climate warming. Precipitation extremes are historically associated with Atmospheric Rivers (ARs). Sixteen global climate models are evaluated for realism in modeled historical AR behavior and contribution of the resulting daily precipitation to annual total precipitation over Western North America. The five most realistic models display consistent changes in future AR behavior, constraining the spread of the full ensemble. They, moreover, project increasing year-to-year variability of total annual precipitation, particularly over California, where change in total annual precipitation is not projected with confidence. Focusing on three representative river basins along the West Coast, we show that, while the decrease in precipitation frequency is mostly due to non-AR events, the increase in heavy and extreme precipitation is almost entirely due to ARs. This research demonstrates that examining meteorological causes of precipitation regime change can lead to better and more nuanced understanding of climate projections. It highlights the critical role of future changes in ARs to Western water resources, especially over California
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