Indiana University-Purdue University Indianapolis (IUPUI) / Taste-and-Odor (T&O) occurrences are a worldwide problem and can locally have extensive socio-economic impacts in contaminated waterbodies. Tracing odorous compounds in surface waters or controlling the growth of producing organisms is particularly challenging. These approaches require the understanding of complex interactions between broad climate heterogeneity, large-scale physical processes such basin hydrology, lake/reservoir circulation, responses of aquatic ecosystems and communities. Eagle Creek Reservoir (ECR), a eutrophic water body, located in central Indiana experiences annual odorous outbreaks of variable durations and intensities that can impair its water quality. Two major compounds, 2-methylisoborneol and geosmin, have been identified as the main culprits occurring seasonally when the reservoir receives high discharges and nutrient loads from its main tributaries. Under these conditions, the growth of T&O-producing bacteria tends to take over other phytoplanktic organisms. Discrete samples collected within the water column during severe outbreaks in 2013 revealed that some bacterioplankton members belonging to Actinobacteria (Streptomyces) and Cyanobacteria (Planktothrix) were involved in the generation of T&O compounds. Most of this production occurred in the upper layers of the water column where higher abundances of key enzymes from MIB and geosmin metabolic pathways were detected. Application of a copper-based algaecide to curb the biosynthesis of bacterial metabolites led to geosmin production (linked to Cyanobacteria) being quickly terminated, whereas MIB levels (linked to Actinobacteria) lingered for several weeks after the algaecide treatment. Significant chemical differences in the association of these metabolites were measured in ECR. Geosmin was dominantly found cell-bound and settling after cellular death increases susceptibility to biodegradation in bottom sediments. MIB was mostly found dissolved making it less susceptible to biodegradation in bottom sediments. Genetic data identified Novosphingobium hassiacum and Sphingomonas oligophenolica (α- Proteobacteria) as potential degraders of geosmin and, four Flavobacterium species (Bacteroidetes) as potential MIB degraders. The role of Eagle Creek natural sediments in the removal of bacterial metabolites via chemical adsorption was also tested but was not proven efficient. Bacterial breakdown activity was demonstrated to be the major loss mechanism of MIB and geosmin.

京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第13205号 / 論農博第2863号 / 新制||農||1062(附属図書館) / 学位論文||H30||N5143(農学部図書室) / (主査)教授 松村 康生, 教授 奥本 裕, 教授 丸山 伸之 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Melt granulation is a versatile process that is underutilized in the pharmaceutical industry. Most pharmaceutical wet granulation and twin-screw extruders can be adapted for melt granulation. Twin-screw melt granulation (TSMG) is of interest since is a continuous process and allows for flexible process design and a high degree of control. TSMG can be used to produce formulations for oral immediate or sustained release. This research focuses on the use of TSMG to taste-mask APIs. Many APIs are bitter or unpleasant tasting. Taste-masking may be required, particularly for products intended for pediatric patients. Taste-masking has been achieved with many different techniques, but a simple, cost-effective method that can be applied to many different APIs is not currently available. A matrix encapsulation approach using continuous twin-screw melt granulation was attempted with three different APIs. The resulting granule properties, particularly particle size, are related to the granulation process parameters. Prediction of taste-masking based on in vitro assessments is challenging and generally clinical evaluation is required. A small-volume dissolution method was developed as a screening test the melt granules. It is not clear if this technique is predictive of clinical taste-masking performance, but it is expected to be an improvement over discrete sampling or typical quality control dissolution methods. The dissolution rate was estimated using the Noyes-Whitney equation and correlated to the mean granule particle size. From this, a simple model for time to a taste threshold could be used to define a design space around the granulation process. / Pharmaceutical Sciences

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Use of liquid administration paradigms in functional magnetic resonance imaging (fMRI) research has rapidly increased and expanded. Despite rapid expansion, there are no studies examining the methods setup of this paradigm. The present study aims to address basic questions about the methodology of liquid administration paradigms using a series of three experiments. These questions include whether using timing files generated by the study computer accurately represent the time of taste receipt, whether variation in methods setup meaningfully impacts time of taste receipt, and whether inaccurate receipt time impacts first-level analysis of fMRI data. Experiment 1 used an equipment setup simulating the running of an fMRI study with three taste stimuli; tasteless solution, chocolate milkshake, and chocolate milk. For each taste stimulus, we captured and compared the times of administration recorded by the study computer and the time of receipt captured using two measurement systems. Experiment 2 used a similar setup with only one taste stimulus: chocolate milkshake. Using high-definition video, we captured the time elapsed as the taste stimulus passed through the tubing at three infusion speeds and varying temperatures. In Experiment 3, we used the fMRI data from a previous study, in which five participants were administered chocolate milkshake to demonstrate how the lag times captured in Experiment 1 affect first-level fMRI data analyses. There were significant differences in time of administration recorded by the computer and time of receipt, demonstrating the existence of a lag time. This lag time was greatest for chocolate milkshake. Semiautomatic pump speed also was significantly associated with lag time. Temperature and length of tubing were not significantly related to lag time. Additionally, our fMRI analyses show that the variation in the methods setup have a meaningful impact on first-level fMRI analyses. When using the computer-generated time that was not corrected for lag time, increased neural activity in response to the chocolate milkshake taste was shown in three out of the five participants. When correcting using the lag time, increased neural activity in response to chocolate milkshake taste was found in all five participants. Overall, this study demonstrates a “proof of concept” that the practice of estimating liquid administration times from computer-generated files may not be accurate, that variation in methods setup may affect the timing in this paradigm, and that these differences in timing introduce variation in the fMRI data of individual participants. / Psychology

Between 4-16% of adults in the United States have experienced difficulty swallowing at some point during their lives. Difficulty swallowing, or clinically referred to as dysphagia, poses increased concern when drinking beverages. While no treatment is currently available, it is often recommended that liquids be thickened to improve the safety of swallowing and prevent liquids from being aspirated in the lungs. However, thickened liquids are poorly accepted by individuals with dysphagia. Taste and flavor suppression has been shown in various thickened liquid matrices, but the mechanisms for understanding these changes in perception are quite complex. Additionally, literature focused on dysphagic patients’ experiences with different types of beverages and clinicians’ experiences with thickening beverages is minimal. The study had two main goals: 1) explore how sensory properties including texture, taste, and flavor affect acceptance of specific thickened liquids and 2) determine challenges clinicians experience with thickening different beverages. This was achieved through a quantitative and qualitative online survey administered to clinicians (n=83; 96% speech-language pathologist) in the United States who work with dysphagia patients. Free-response questions related to thickening issues highlighted challenges with carbonation, temperature, and dairy products. Coffee, water, soda, milk, and oral nutritional supplements were the most complained about thickened beverages, respectively. Disliking of texture was a common complaint for each beverage likely due to the dissimilarity to the unthickened version and challenges associated with thickening. Off-flavors were reported for each beverage and were the most present in water. Additionally, clinicians noted the thickened version of the beverage typically has less flavor. To increase the acceptance of thickened liquids, clinicians believe the texture and flavor need significant improvements. Interdisciplinary work in the field of food science is needed to create a smoother consistency, more stable thickness across time and temperature, and improved flavor/taste to develop more enjoyable beverages for dysphagic patients.