• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • Tagged with
  • 451
  • 451
  • 451
  • 367
  • 367
  • 95
  • 41
  • 40
  • 30
  • 24
  • 21
  • 20
  • 19
  • 19
  • 18
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

The effect of a complex pollutant on the cell count of cyanophyta in Little Lick Creek

Spinner, Ronald W. 03 June 2011 (has links)
Selected physicochemical properties of Little Lick Creek, in Hartford City, Indiana, were determined in the fall of 1969. Subsurface samples from five stations, two upstream and two downstream from a discharge point: at the. Minnesota Mining and Manufacturing Companywere analyzed. A complex effluent containing a dye entered the creek from the paper plant. Dissolved oxygen and biochemical oxygen demand determinations of the water downstream from the discharge displayed changes in water quality of the creek. The water temperature rose significantly after the discharge water entered the creek. A cell count study of the Cyanophyta of the creek was also determined.Little Lick Creek was considered polluted below the paper products plant discharge based on the observed changes in the water tested. Cyanophyta populations were apparently reduced by the effluent.Ball State UniversityMuncie, IN 47306
112

The effects of acridine on minute mutants of bacteriophage T4

Whitaker, William J. 03 June 2011 (has links)
Wild-type and minute mutants of the T4 strain of bacteriophages were treated with 1.0-12.0 ug per ml concentrations of aminoacridine. Escherichia coli was the host organism for the bacteriophages.Concentrations of acridine less than 2.0 ug per ml had no noticeable effect on wild-type ormmutant plaque formation. Two and one half to seven ug per ml concentrations of acridine reduced the size (diameter) and number of plaques formed from both. Concentrations greater than 7.0 ug per ml completely inhibited the growth of both.The host organism (Escherichia coli) was not affected by the acridine.Ball State UniversityMuncie, IN 47306
113

Tumor cell mitotic incidence in mice pretreated with autochthonous and syngeneic incoula

Stovall, William E. 03 June 2011 (has links)
Tumor bearing mice pre-treated with autochthonous and syngeneic inocula were found to have an enhanced immune response. Mitotic indices of the tumors from three experimental groups were significantly lower than those of the two control groups. The treated control group which received Freund's adjuvant also had a significantly lowered mitotic index, but was still significantly higher than the three experimental groups.The immune response was evidenced by reticuloendothelial involvement and anaphylactic reactions in various animals. Abnormalities found in the livers consisting of portal infiltration of reticular calls and megakaryocytes were observed. The tumor sections observed showed increased lymphocytic infiltration,There were no significant differences in the mitotic indices between the syngeneic and autochthonous recipients. A lack of antigenic differences in the tumors utilized is thus indicative of this finding.Ball State UniversityMuncie, IN 47306
114

The bactericidal effect of low ozone concentrations on experimentally airborne Aerobacter aerogens, Bacillus megatherium, and Escherichia coli B

Techy, Geza B. 03 June 2011 (has links)
AbstractThe bactericidal effect of ozone at concentrations of 1 and 2 p.p.m. by volume, was tested on separately atmized resting cell suspensions of Aerobacter aerogenes, Bacillus megathreium, and Escherichia coli B impinged on Millipore filters. The exposure of each species required the use of 18 randomly selected filters containing impinged organisms. Of the 18 filters, 6 were used in the control. The temperature and the relative humidity of the ozone flow were approximately 25ºC and 20 per cent, respectively, while the flow-rate across each filter was 3 liters per minute. It was found that all of the organisms tested were completely destroyed by both 2 and 2 p.p.m. ozone within 2 minutes of exposure.Ball State UniversityMuncie, IN 47306
115

Syntheses and decomposition of 3-vinyl-1-pyrazolines

Garrison, Joseph 03 June 2011 (has links)
A versatile method for the reduction of 2-pyrazolines was developed in this research. In every reduction attempt, aluminum trihydride successfully reduced the carbonnitrogen double bond. Since carbon-carbon double bonds were stable to aluminum trihydride, the preparation of 3-vinyl1-pyrazolines by a new synthetic route became possible. Using this method, 3,3-dimethyl-5-(1-isobutenyl)-1-pyrazoline was prepared. This compound was thermalytically decomposed, and the products of the decomposition were determined.In the course of this research, a one-step method for the preparation of cyclopropanes in high yield from 2pyrazolines was uncovered, but not fully developed. A new route to alpha-gamma-diamino compounds was also accomplished with the use of aluminum trihydride.Ball State UniversityMuncie, IN 47306
116

The fatty acid desaturase system of Penicillium chrysogenum

Mills, Verne M. 03 June 2011 (has links)
The conversion of stearic acid and lauric acid to unsaturated fatty acids by the desaturase system of Penicillium chrysogenum was investigated by incubating cell free fractions prepared from mycelial sonicates with the radioactively labeled fatty acids and analyzing the reaction products. In some experiments exogenous acyl carrier protein (ACP) or coenzyme A (Co.A) was added to the incubation mixtures. The percentage of radioactive label appearing in unsaturated fractions was regarded as a measure of the activity of the desaturase system.Desaturase activity was detected in both the 15,000 x g particulate and supernatant fractions. Only small percentages of 1-14C-stearyl-CoA were converted to unsaturated fatty acids; 1-14Clauryl-CoA was apparently more readily desaturated. The desaturase system was found to be inhibited by exogenous ACP, but not by exogenous CoA. This suggested that the fatty aryl-CoA thioesters were converted to thioesters of ACP prior to desaturation.Ball State UniversityMuncie, IN 47306
117

Design and fabrication of a miniaturized nuclear quadrupole resonance spectrometer which will operate in liquid nitrogen

Konkle, Guy Clifton 03 June 2011 (has links)
A miniaturized super-regenerative nuclear quadrupole resonance spectrometer was fabricated in this project. The spectrometer was constructed using thin-film chromium resistors, gold-nickel conductors, and field effect transistors. The unit operated at room temperature and at 77º K between the frequencies of 24.860 and 44.300 MHs.The spectrometer was fabricated on a ceramic substrate which was 5.08 x 5.08cm. The films consisted of vacuum deposited chromium, electroless plated nickel, and electroplated gold. The resistor-conductor pattern was photo-etched from the films and the remaining components attached to the films to form the circuit.The spectrometer was encased in a stainless steel belljar with the sample coil extending from the bottom and the signal and power leads extending from the top of the belljar. The unit was immersed in liquid nitrogen and the characteristics monitored as the temperature dropped.The spectrometer operated in the liquid nitrogen, but failed to yield a signal for a paradichlorobenzene sample. The spectrometer exhibited poor frequency selectivity and a frequency change of 2MHz (6%) in going from room temperature to liquid nitrogen (77º K).Ball State UniversityMuncie, IN 47306
118

Determination of the ratio of magnetic dipole to electric-quadrupole radiation in the atomic spectral line 6647A(D5/2-D3/2) of HgII

Rettig, Terrence W. 03 June 2011 (has links)
This thesis has involved an attempt to determine the ratio of electric-quadrupole radiation to magnetic-dipole radiation for the forbidden transition 6647A(2D5/2-2D3/2) of ionized mercury. The high resolution needed for this type of work was obtained by using a 14mm Fabry-Perot etalon and a three prism glass spectrograph, The mercury source was a heated eleotrodeless quartz discharge tube excited by an rf oscillator. A large electromagnet was used to obtain the Zeeman effect. This is the first time that the 6647A transition has been analyzed. The experimental results for the longitudinal view show agreement with predictions for the Zeeman components giving complete verification of the identity of the line but the intensity patterns show a possible disagreement with theoretical predictions for the ratio of magnetic-dipole to electric-quadrupole radiation.Ball State UniversityMuncie, IN 47306
119

A biosystematic comparison of Asplenium platyneuron and Athyrium pycnocarpon

Banks, James B. 03 June 2011 (has links)
This thesis has examined a long existing conflict between two ferns, Asplenium platyneuron and Athyrium pycnocarpon. The study included habitat, external and internal morphological characteristics, and biochemical analyses of the free amino acids. Major emphasis was placed upon vascular structure and arrangement in the stipes, roots, and rhizomes.Biochemically, the free amino acids were separated by one-dimensional descending paper chromatography. All areas investigated were either photographed or drawn and presented in the text of the thesis.Ball State UniversityMuncie, IN 47306
120

Nuclear quadrupole resonance spectrometer using field-effect transistors

Craig, Ronald E. 03 June 2011 (has links)
This thesis includes elementary introductions to nuclear quadrupole resonance (NQR) detection and fieldeffect transistors (PET). The construction and operation of the FET-NQR detector, as originally designed by Viswanathan, Viswanathan and Sane and published in Rev. Sci. Instr. 39,472 (1968), is discussed extensively. The thesis also contains a step by step discussion of the construction of an alternate PET-N'QP detector. Although the alternate detector never functioned properly, the information gathered would aid anyone desiring to design and construct a new NQR detector.Ball State UniversityMuncie, IN 47306

Page generated in 0.085 seconds