Cryptosporidium is a protozoan parasite that causes gastroenteritis in man and animals. One mode of transmission of cryptosporidiosis is by the fecal-oral route. A method was developed for the concentration and detection of Cryptosporidium oocysts in water to study this organism's occurrence in the environment and its potential for waterborne disease transmission. Oocysts from an infected calf were used in experiments and monoclonal antibody labeled with fluorescein isothiocyanate was used for oocyst detection. A concentration method was developed using spun polypropylene cartridge filters. Optimal conditions for concentration, filter elution, filter porosity, and detection were determined by passage of 20-L volumes of tapwater seeded with 10⁵-10⁶ oocysts through the filters. The best method incorporated a 1-μm filter; 2 L eluent containing 0.1% Tween 80; backflush of eluent through filter; cutting the filter; mechanically shaking filter and eluate; and for 378-L volumes, three successive washings of filter material. Modifications were made when attempting to recover 10²-10³ oocysts in 378-L volurnes. These included addition of 1% Tween 80 and 1% sodium dodecyl sulfate (both made in distilled water) to the pellet, followed by homogenization, sonication, Sheather's flotation, and examination of the entire final preparation using a slide antibody test. To distinguish oocysts from other organisms such as yeast which may cross-react with the antibody, crystal violet and acid-fast stains were used. Cryptosporidium oocysts were isolated from secondarily treated sewage and identified on the basis of size, shape, reaction with antibody, acid-fastness, and inability to take up crystal violet. Limited studies with hepatitis A virus (HAV), a cause of waterborne disease, were performed using the HAS-15 strain of HAV and the FRhk-4 cell line. Four procedures used for concentration and detection of HAV in water were developed. They were radioimmunoassay for detection of viral antigen, production of HAV stocks, radioimmunofocus assay for quantitation of infective virus, and inhibition of certain strains of enteroviruses other than HAV, by guanidine.

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This bachelor thesis has been carried out at the company Didamus which is located in Mjärdevi, Linköping. The company is currently developing a dive-console which aims to take the scuba diving experience to a whole new level and also to make scuba diving more secure. An assembly of scuba divers that can communicate with each other during a dive session might be the difference between life and death. Many seas around the world have muddy water which means poor visibility. In each situation a computer providing a scuba diver with information about others connected to the network, hazardous accidents can possibly be avoided.  The network itself consist of 10 nodes that need a network protocol which provides stability and reliability for every participant. The nodes themselves have a distributed responsibility to make the network reliable. The type of network implemented was a regular Time Division Multiple Access (TDMA) network where different nodes were given permission to access the medium in different instances of time. A global reference of time is always needed in a TDMA network to make it function properly. In a typical TDMA network a GPS-service gives each and every node information about the global time.  Unfortunately, GPS-services do not work well in water so a Master-Slave method was used instead. The master provides the rest of the nodes in the network with a global time reference. After a successful reception of a global time reference, the slave will be granted access to the network. The communication between the nodes is based on ultrasonic waves propagating in the water. The velocity of ultrasonic waves in water is only 1500 meters per second, explained in Discovery of Sound in the Sea by University of Rhode Island, which is a relatively slow signal speed. With the slow velocity taken into account an efficient TDMA protocol was developed, to perform communication under water.

Thesis (M.S. - Nutrition and Food Science)--University of Arizona, 1986. / Includes bibliographical references (leaves 34-36).

Thesis (Ph. D. - Microbiology and Immunology)--University of Arizona, 1985. / Includes bibliographical references (leaves 134-143).

Thesis (Ph. D. - Microbiology and Immunology)--University of Arizona, 1985. / Bibliography: leaves 142-161.

Thesis (Ph. D. - Microbiology and Immunology)--University of Arizona, 1985. / Includes bibliographical references (leaves 118-127).

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Thesis (M.S. - Microbiology and Immunology)--University of Arizona, 1985. / Includes bibliographical references (leaves 54-59).