Twenty-two adult male subject were randomly assigned to four complete liquid diets at four different fiber levels; one without added soy polysaccharide fiber which served as a control. All subjects were rotated. through four, eleven day controlled feeding periods. Complete fecal samples were collected and composited from the last five days of each eleven day period for fiber analysis. Fasting blood samples were taken on the morning prior to starting each new dietary period for plasma total cholesterol (TC), total triglycerides (TG), and high density lipoprotein-cholesterol (HDL-C) analyses, Low density lipoprotein-cholesterol (LDL-C) was determined by calculation. Increased mean dietary fiber intake led to a significant (P<.05) increase in fecal fiber from 0.4 g per day to 2.9 g per day. Mean apparent fiber digestibility significantly (P<.05) decreased from 92% on the control diet to 70% on the intermediate fiber diet. There was a nonsignificant increase in apparent fiber digestibility from the intermediate fiber diet (70%) to the high fiber diet (76%). When subjects went from self-selected diets to the zero-cholesterol, liquid formula diets, significant (P<.05) decreases were seen in plasma TC (from 164 mg/dl to a range of 129 to 136 mg/dl), LDL-C (from 108 mg/dl to a range of 81-85 mg/dl), TG (from 85 mg/dl to a range of 64 to 72 mg/dl), TC/HDL-C ratios (from 4.6 to an average of 3.8), and LDL-C/HDL-C ratios (from 2.9 to an average of 2.4). HDL-C levels did not change from the self-selected diet to the zero-cholesterol liquid formula diets (from 38 mg/dl to a range of 35 to 38 mg/dl). The addition of 20, 30, and 40 g of soy polysaccharide a fiber to the low residue control diet did not result in any further changes in plasma TC (131 mg/dl versus 129 mg/dl, 136 mg/dl, and 132 mg/dl respectively), TG (72 mg/dl versus 64 mg/dl, 69 mg/dl, and 72 mg/dl, respectively), HDL-C (36 mg/dl versus 35 mg/dl, 38 mg/dl and 37 mg/dl respectively), LDL-C (81 mg/dl versus 81 mg/dl, 85 mg/dl, and 82 mg/dl, respectively), TC/HDL-C ratios (3.8 versus 3.9, 3.8, and 3.8, respectively), and LDL-C/HDL-C ratios (2.4 versus 2.5, 2.4, and 2.3, respectively). At the end of the study when subjects went back to self-selected diets plasma TC, LDL-C, and HDL-C all significantly (P<.05) increased. / Master of Science

Weed seeds contaminating cattle feed can pass unaffected through the animal's digestive tract and may germinate when manure is returned to land as fertilizer. This investigation was undertaken to determine the effects of anaerobic fermentation of raw manure on the viability of Johnsongrass and Fall Panicum seeds which may be present in the waste. Dairy waste containing Johnsongrass and Fall Panicum seeds were subjected to batch and continuously-fed anaerobic fermentation processes in laboratory-scale digesters. The effect of influent solids concentration (4% and 6%) and retention time (15 days and 20 days) on seed viability was observed. The experiments were carried out in the mesophilic temperature range [35°C±1ºC]. Fall Panicum seeds were found to be less resistant to anaerobic digestion than Johnsongrass seeds. Greater seed destruction was achieved in 20-day digesters than in the 15-day digesters. The influent solids concentrations did not have significant effect on seed viability. By applying the Schafer-Chilcote seed population model, it was observed that the fermentation process was more effective in destroying non-dormant seeds than dormant seeds. / Master of Science

M. Arch.

The self noise output of switched-capacitor (SC) filters was examined. The two main noise sources in SC filters are switch transistors and the operational amplifiers. These noise sources were modeled as switch thermal white noise and op-amp input white noise. The existence of direct and sample-and-held noise outputs were demonstrated. The direct noise, resulting from direct circuit path, was shown to be relatively small: While the sample-and-held noise, arising from the direct noise samples, dominates the total noise output because of the aliasing effect of direct white noise. Z-domain analysis was performed on the Z-domain noise models of SC filters to evaluate the sample-and-held noise. A SC integrator, a SC biquad and a SC 7th order filter were analyzed. The predicted noise outputs of the last two filters were compared with their experimental results and good correlation between the two results has been obtained. / M.S.

M. S.

Endogenous phosphorylation was measured in soluble fractions at four stages of Dictyostelium discoideum development. A peak of activity occurred at the slug stage, coincident with the appearance of cyclic AMP-dependent protein kinase. After partial purification by DE-52 cellulose and Sephacryl S-300 chromatography, cyclic AMP dependency of six cytosolic proteins was observed, with apparent subunit molecular weights of > 200,000, 110,000, 107,000, 91,000, 75,000, and 69,000. Phosphorylated bands at 107,000 and 91,000 MW were found to be specific for a partially-purified catalytic subunit prepared from the Dictyostelium holoenzyme form. / M.S.

Lignin based polyurethane films were synthesized by solution casting from hydroxypropyl lignins and diisocyanates. Kraft and steam explosion lignin, hexamethylene diisocyanate (HDI) and tolylene diisocyanate (TDI), were used for the study. It was found necessary to use stoichiometric excess amounts of diisocyanates in the synthesis of the thermosetting polyurethanes. The investigation primarily addresses the effect of synthesis variables and soft segment incorporation on the thermal and mechanical properties. The first part of the study examined the effect of lignin type, of diisocyanate type and of composition (NCO/OH ratio). Stoichiometric excess was found to cause a significant increase in the glass transition temperature. Use of HDI resulted in films with lower moduli as compared to TDI. NCO/OH stoichiometry variation had no noticeable effect on modulus or tensile strength. In the second part of the study involving incorporation of soft segments, four polyethylene glycols were used. No soft segment phase in the network was detectable by differential scanning calorimetry or dynamic mechanical analysis. The glass transition temperature of lignin phase dropped by as much as 70°C for HDI and 115°C for TDI based polyurethanes with inclusion of glycols up to 25% of the polyol weight. The swelling tendencies showed an expected increase with glycol content. Effect on mechanical properties were more pronounced in HOI than in TDI based polyurethanes. The modulus and tensile strength decreased, and the ultimate strain values increased with polyethylene glycol content. Last part of the study involved synthesis and characterization of kraft polyurethanes with polybutadiene glycol with functionality in excess of 2.0. The miscibility of this phase with hydroxypropyl lignin phase was found to be poor as observed by scanning electron microscopy. Glass transition temperature for the lignin phase increased with polybutadiene glycol content of the polyurethane in contrast to observations on polyethylene glycol modified polyurethanes. There were no significant improvements in tensile properties. The incompatibility of soft segments was seen to result in a more condensed lignin phase, and was thus found to be the major limitation in its applicability in modification of the network properties. The study demonstrates the utility of concept of network modification in the synthesis of lignin based thermosetting polyurethanes. By proper choice of synthesis variables, and with the use of glycols of sufficient compatibility, significant improvements in properties can be realised in these polyurethanes. / M.S.

The effect of a range of storage temperatures on produce condition was studied. Two or three cultivars or peaches, nectarines, plums, apricots, strawberries, grapes, pears, peppers, one cultivar of blackberries, tomatoes, and cabbages were chosen for the experiment. The storage temperatures (21°C, 15°C, 10°C, 4°C, 0°C) and humidity (about 80% RH) were maintained during the experiment. Observations were made on weight loss, total loss, disease, appearance and visual storage life. Percent weight loss among cultivars was not significantly different (5% level) for most of the produce (two-way factorial arrangement), but date of harvest resulted in a significant difference in percent weight loss of peppers. The range of percent weight loss varied, depending on the type of the produce. Berries lost moisture faster than other fruits. Rate of moisture loss decreased as storage time increased. Beginning at 4°C, for every 5°C rise of temperature, percent weight loss roughly doubled for most of the produce. Total loss in this study was mostly caused by physiological disorders related to ripening and aging in the long storage period and decay caused by fungi on produce stored at high temperatures. The length of storage life was ascertained for cultivars studied. / M.S.

Anaerobic bacteria isolated from Kepone-contaminated sediment were screened for their ability to degrade Kepone under anaerobic conditions. The most extensive degradation was produced by denitrifying bacteria grown on benzoate-nitrate medium. In enrichment cultures, Kepone was transformed more extensively than by pure cultures isolated from the enrichments. A gram negative-faculative rod, called K bacterium, transformed 8.8% of the Kepone in a benzoate-nitrate medium in the presence of 2000 ug/ml potassium nitrate under anaerobic conditions. Kepone transformation by K bacterium increased to 21.1% when the potassium nitrate concentration in this medium was 500 ug/ml of medium. Although monohydro-Kepone and dihydro-Kepone were produced as products of the transformation, less than 20% of the transformed Kepone was recovered as these products. Both K bacterium and the enrichment culture transformed [¹⁴C]Kepone. No ¹⁴CO₂, or new radioactive insoluble or soluble products were detected in spent media. Products which were more polar than Kepone, but could not be identified, were observed in GLC chromatograms. K bacterium attached to the Kepone crystals and was pleomorphic during Kepone transformation. These data support the hypothesis that Kepone is transformed when it is used by certain anaerobes as an alternate electron acceptor. / M.S.

Nutrients of animal manures digested anaerobically for biogas production are highly conserved. The objectives of this study are to evaluate changes in the fertilizer value of poultry manure following digestion. Total kjeldahl N (TKN) was completely recovered during digestion, however, NH₄⁺N was 159 and 151% recovered fran pilot scale plug flow and laboratory scale digesters. This indicates that added organic N is mineralized. Recovered N and K were associated with liquid fractions and P, Ca, Mg and micronutrients were associated with solids of digested slurries. The mineralization of organic N fran soil applied effluent was 2.3 times greater in comparison to influent over a 33.5 week laboratory incubation period. Higher mineralization is due to segregation of decay resistant solids into the settled sludge and the decrease in surface area of suspended solids during digestion. Significantly higher NH₃N volatilization (3 fold to 62%) of land applied effluent compared to influent is due to increases in pH and NH₄⁺N:TKN during digestions. Yields of corn (Zea mays L.) grain at two sites were similar for effluent, influent and urea treatments receiving identical N rates. However, the silage yield of the urea treatment was significantly 19.9% higher than that of the effluent at site 1. Yields and ear leaf N were highly correlated with applied N discounted for NH₃N losses. This indicates that organic N of the effluent and influent become plant available during the growing season. / M.S.