<p>Recent years there has been a large increase in the worldwide sales of cultured products containing probiotics. The obstacle in the production of fermented products incubated with probiotic strains is its effect on sensory, chemical and physical properties. This Master´s Thesis investigates how extended storage times in fermentation tank as well as buffer tank during production of probiotic yoghurts affect final product quality. Through experimental studies, maximum storage times for probiotic yoghurts were to be recommended. The study includes analyses of pH, viscosity, stability, acetic acid concentration, microbial viability and sensory evaluations.</p><p>Design of experiments (DOE) was used to construct a 3²-factorial design for the experiment where different storage times were tested. The analyses showed that:</p><ul><li>pH decreases with both storage time in fermentation tank and buffer tank.</li><li>Viscosity increases with long storage times in fermentation tank, while it decreases with long storage times in buffer tanks.</li><li>Many samples had a sandy/grainy and slimy texture which could be related to high levels of Bifidobacteria or high fermentation temperatures.</li><li>High levels of acetic acid was found in all samples.</li><li>All measurements data where within the specification limits, whereas no recommendation for maximum storage times during production could be given.</li></ul>

Recent years there has been a large increase in the worldwide sales of cultured products containing probiotics. The obstacle in the production of fermented products incubated with probiotic strains is its effect on sensory, chemical and physical properties. This Master´s Thesis investigates how extended storage times in fermentation tank as well as buffer tank during production of probiotic yoghurts affect final product quality. Through experimental studies, maximum storage times for probiotic yoghurts were to be recommended. The study includes analyses of pH, viscosity, stability, acetic acid concentration, microbial viability and sensory evaluations. Design of experiments (DOE) was used to construct a 32-factorial design for the experiment where different storage times were tested. The analyses showed that: pH decreases with both storage time in fermentation tank and buffer tank. Viscosity increases with long storage times in fermentation tank, while it decreases with long storage times in buffer tanks. Many samples had a sandy/grainy and slimy texture which could be related to high levels of Bifidobacteria or high fermentation temperatures. High levels of acetic acid was found in all samples. All measurements data where within the specification limits, whereas no recommendation for maximum storage times during production could be given.

No description available.

Thesis--University of Oklahoma. / Includes bibliographical references (leaves 51-55).

Lophelia pertusa is a cosmopolitan cold-water coral, often found in aphotic waters (>200m). Aggregations of L. pertusa (reefs) provide important habitat to many invertebrate and fish species and act as biodiversity hotspots in the deep sea. The health and diversity of these reefs is of vital importance to deep-sea ecosystems, and the microbial consortia associated with L. pertusa form the most basic ecological level. Deciphering the diversity and function of these microbes provides insight into the roles they play in maintaining reef health. This dissertation takes microbiological techniques that are used in shallow-water coral microbial research and applies them to L. pertusa. A flaw in a primer set, which is commonly used in the molecular genetics method Polymerase Chain Reaction (PCR) to obtain data on coral-associated microbes, is discussed and an alternative approach is presented. In addition, two culture-based studies are employed to catalogue diversity and explore functional differences in strains of both bacteria and fungi. The cultured bacteria were tested for resistance against six antibiotics that affect a variety of cellular targets to elucidate strain level differences. The first cultured fungi ever described from L. pertusa were identified by molecular techniques and assayed using Biolog plates to test their metabolic capabilities. Preliminary data analysis on metagenomic libraries of the microbial-size fraction of L. pertusa is presented and discussed in the context of microbial diversity and function, bridging the gap between culture-based work on function and culture-independent work on diversity.

Radiobiological irradiation can be performed using appropriately collimated sealed source radioisotope machines such as Co-60 units, as well with X-ray tubes and linear accelerators. The increasing research interest in delivering organ-specific or whole body animal external irradiation has led to the introduction of dedicated X-ray units for research purposes. In this work, the proprieties of a kilovoltage X-ray biological irradiator, the Faxitron cabinet X-ray system model CP160, are investigated and dosimetrically characterized. Calculation formalisms for everyday use of the radiobiological irradiator in laboratory conditions, specifically for cell cultures and small animals total body irradiation, were developed following the AAPM TG-61 protocol. The quality of the X-ray beams generated by this irradiator was found to range between HVL 0.7 mm Cu for a 160 kVp 0.5 mm Cu filtered beam, and HVL 0.07 mm Al for a 20 kVp non-filtered beam. Our calculation formalisms for cell cultures and small animal irradiations were found to be valid within +/-5%.

What changes in our brain when we learn? This is perhaps the most intriguing question of science in this century. In an attempt to learn more about the inner workings of neural circuitry, I studied cultured 2-dimensional networks of neurons on multi-electrode arrays (MEAs). MEAs are ideal tools for studying long-term neural ensemble activity because many individual cells can be studied continuously for months, through electrical stimulation and recording. One of the most prominent patterns of activity observed in these cultures is network-wide spontaneous bursting, during which most of the active electrodes in the culture show elevated firing rates. We view the persistence of spontaneous bursting in vitro as a sign of arrested development due to deafferentation. Substituting distributed electrical stimulation for afferent input transformed the activity in dissociated cultures from bursting to more dispersed spiking, reminiscent of activity in the adult brain. Burst suppression reduced the variability in neural responses making it easier to induce and detect functional plasticity caused by tetanic stimulation. This suggests that spontaneous bursts interfere with the effects of external stimulation and that a burst-free environment leads to more stable connections and predictable effects of tetanization. Moreover, our culture models continuously receive input stimulation in the form of background electrical stimulation, and so better resemble the intact brain than isolated (non-continuously stimulated) cultures. The proportion of GABAergic neurons in the cultures was significantly increased (p<1e-2, paired t-test) after burst-quieting for 2 days, suggesting that burst suppression operated through the homeostatic control of inhibitory neurotransmitter levels. We also studied the role of spontaneous bursts as potential carriers of information in the network by clustering these spatiotemporally diverse bursts. Spontaneous burst clusters were stable over hours and tetanic stimulation significantly reorganized the distribution of the clusters. In summary, this body of work explores the rules of network-level functional plasticity and provides the input (electrical stimulation) output (spatiotemporal patterns) mappings for behavioral studies in embodied hybrid systems. The results of this study may also have clinical implications in the development of sensory prostheses and treatment of diseases of aberrant network activity such as epilepsy.

Thesis (Ph.D. in Immunology) -- University of Colorado at Denver and Health Sciences Center, 2006. / Typescript. Includes bibliographical references (leaves 129-141). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 5 uppsatser.