<p>A common modification of starch is esterfication with anhydrous octenyl succinic acid (OSA).  The modification makes the polymer surface active and it also incorporates a carboxyl group to the starch, which can be negatively charged. The characteristics of OSA starch make it interesting for usage in combination with egg yolk proteins in food emulsions. It is not only the individual ingredients that affect the product; interactions between ingredients and ingredient-dispersion medium have a great impact on factors such as structure and stability. Knowledge about how the interactions affect emulsion properties would make it possible to predict the behavior of an emulsion, which would be a great advantage in the formulation of food emulsions. Therefore, this is a subject of interest.</p><p>The purpose of this master thesis was to further investigate the interactions between OSA starch and α – β-livetin in solutions and in emulsions. First, the charges of the macromolecules were studied by titration. Interactions in solution were then analyzed through turbidity and solubility measurements. The adsorption of OSA starch onto livetin and the interfacial rheology were also studied. Finally, an emulsion stability experiment was made.</p><p>Strong interactions between the two macromolecules were observed in solutions at pH 4.0. This was probably due to hydrophobic interaction; however it could also be explained by electrostatic interaction. In the emulsions the adsorption of starch onto livetin was highest at pH 4.5, and then decreased with increasing pH values. The absence of OSA starch adsorption at pH 4.0, despite the strong interaction in solution, could be explained by complex formation immediately in solution. Less starch would then be able to reach the interface and adsorb. In the interfacial rheology experiments, an indication of decreased complex dilational modulus of the interfacial layer, caused by OSA starch addition was seen at low pH values. This could be due to aggregation of the proteins and formation of an uneven interfacial layer. OSA starch would then be able to adsorb and disturb the elasticity. Some differences in the stability of an emulsion only containing livetin, and an emulsion with both livetin and OSA starch could be observed. However, more investigations are needed to be made to understand the underlying mechanisms.</p>

A common modification of starch is esterfication with anhydrous octenyl succinic acid (OSA).  The modification makes the polymer surface active and it also incorporates a carboxyl group to the starch, which can be negatively charged. The characteristics of OSA starch make it interesting for usage in combination with egg yolk proteins in food emulsions. It is not only the individual ingredients that affect the product; interactions between ingredients and ingredient-dispersion medium have a great impact on factors such as structure and stability. Knowledge about how the interactions affect emulsion properties would make it possible to predict the behavior of an emulsion, which would be a great advantage in the formulation of food emulsions. Therefore, this is a subject of interest. The purpose of this master thesis was to further investigate the interactions between OSA starch and α – β-livetin in solutions and in emulsions. First, the charges of the macromolecules were studied by titration. Interactions in solution were then analyzed through turbidity and solubility measurements. The adsorption of OSA starch onto livetin and the interfacial rheology were also studied. Finally, an emulsion stability experiment was made. Strong interactions between the two macromolecules were observed in solutions at pH 4.0. This was probably due to hydrophobic interaction; however it could also be explained by electrostatic interaction. In the emulsions the adsorption of starch onto livetin was highest at pH 4.5, and then decreased with increasing pH values. The absence of OSA starch adsorption at pH 4.0, despite the strong interaction in solution, could be explained by complex formation immediately in solution. Less starch would then be able to reach the interface and adsorb. In the interfacial rheology experiments, an indication of decreased complex dilational modulus of the interfacial layer, caused by OSA starch addition was seen at low pH values. This could be due to aggregation of the proteins and formation of an uneven interfacial layer. OSA starch would then be able to adsorb and disturb the elasticity. Some differences in the stability of an emulsion only containing livetin, and an emulsion with both livetin and OSA starch could be observed. However, more investigations are needed to be made to understand the underlying mechanisms.

No description available.

Student Number :9600874K - MSc research report - School of Electrical Engineering - Faculty of Engineering and the Built Environment / Telecommunication networks have evolved from voice only single service networks to multimedia networks providing bearer services such as voice, data and video transportation. Moreover, these networks, collectively called Next Generation Networks (NGNs), enable rapid creation, deployment and management of advanced services in an efficient manner. However, the initial business model of telcos was to internally develop and provide these advanced services to customers. In this monopolized environment, service development is driven by technological availability rather than customer demands. Furthermore, vendor specific network elements prohibit the development of re-useable service components, which in turn increases the time-to-market of services. Deregulation and advances in Distributed Computing Systems (DCSs) are driving towards open networks and rapid service delivery. Third party Application Service Providers (ASPs) are envisioned to develop and supply the services, with the telco providing bearer services. The use of softswitch architectures such as Open Service Access (OSA) / Parlay (OSA / Parlay) in an open NGN environment abstract services from core network elements through its Application Programming Interface (API). Services are thus decoupled from vendor and protocol specific network equipment and can be provided across a plethora of network architectures. One major advantage of NGN is the ability to provide bearer service in a mobile environment. Location Based Services (LBSs) are envisaged to be an important class of services provided in the NGN environment. For an LBS service to be complete, a geospatial database is necessary to provide location information. This report documents the design and implementation of a Geospatial Data Access Service Capability Feature (GDASCF) as an extension to the OSA / Parlay gateway. The GDASCF encapsulates necessary APIs that offer uniform access to query geospatial databases. One key component of the design is the realization of the Adapter layer which adapts function calls to an appropriate Database Management System (DBMS). The introduction of the GDASCF and Adapter layer provides a solution which results in flexible and rapid service creation.

No description available.

Nonalcoholic fatty liver disease (NAFLD) afflicts approximately a quarter of the world’s general population and more than half of the world’s obese population. The disease is characterized by a spectrum of liver pathologies, ranging from simple steatosis or the accumulation of fat within hepatic tissue to steatohepatitis comprised of inflammation and fibrosis, also known as NASH. Simple steatosis is relatively asymptomatic and is considered benign, but NASH poses great risk for advanced forms of liver disease, such as cirrhosis and hepatocellular cancer. Obstructive sleep apnea(OSA) is a respiratory disorder involving the recurrent collapse of the upper airway during sleep. Consequently, the patient experiences constant arousals due to constant blockage followed reopening of the airway. Aside from poor quality and disruption of sleep, chronic intermittent hypoxia (CIH) is also present during OSA. The presence of CIH leaves many vital organs deprived of adequate oxygen to carry out normal physiological function. In response to this hypoxic state, the body upregulates many transcription factors, many of which control inflammatory processes. In recent studies, chronic and recurrent hypoxia generated from OSA has been implicated in the onset and progression of NAFLD. The pathogenesis of NAFLD is believed to be associated with metabolic imbalances, mainly obesity and insulin resistance, both of which also overlap with OSA. These conditions are the main factors in predisposing a patient suffering from OSA to the effects of CIH. Multiple lines of evidence suggest that CIH may accelerate the development of NAFLD through 1) Lipolysis of hepatic adipose tissue and increased hepatic free fatty acids; 2) Upregulation of lipid biosynthetic through CIH; 3) Upregulation of hypoxia-inducible factor 1-alpha by CIH inducing liver inflammation and fibrosis. The primary focus of this thesis will attempt to determine a possible link between OSA and NAFLD. Through citation of prior scientific studies, it will formulate the theory of OSA as a predisposing factor in the heightened risk of NAFLD pathogenesis and development to more severe, terminal stages. Primarily, the review of literature will highlight the metabolic imbalances of obesity and insulin resistance and how each is related to OSA and NAFLD. Ultimately, deposition of fat and inflammation triggered through various chemical factors connected to OSA will depict both the generation and progression of NAFLD.

Habitat modification is the primary cause of amphibian population declines worldwide. Some species survive in modified habitats whereas others become restricted to small, isolated forest patches. Although many studies compare species richness and composition between modified and intact habitats, the factors and mechanisms that maintain biodiversity in these landscapes are poorly understood. I asked how life history traits and habitat features influence interspecific variation in frog occupancy patterns in tropical pasture and forest. To identify mechanisms underlying occupancy patterns, I used experiments to examine how abiotic conditions in different habitats influence the vital rates of tadpoles. I also explored whether tadpoles use a carnivorous foraging strategy to improve performance in nutrient-poor, ephemeral pools in pasture. Although modified and intact habitats offer abiotic environments that differ in quality for frogs, pastures contribute to the maintenance of biodiversity in fragmented landscapes. I detected an equal number of species but substantially different assemblage composition in forest and pasture. Species that occurred in pasture had different traits than those in forest, including larger body sizes, larger clutch sizes, larger geographic ranges, and reproductive modes that depend on water. The occurrence of pasture-specialists was associated with habitat features at small spatial scales, whereas the occurrence of forest-specialists was associated with habitat features at small and large spatial scales. An experiment indicated that abiotic conditions in pastures may deter or facilitate adult movements to breeding sites. Behavioral selection of sites by two model species was consistent with tadpole performance. Tadpoles of a pasture-specialist performed well across the pasture-forest gradient, but abiotic conditions in pasture facilitated faster growth and development than in edge or forest. In contrast, tadpoles of a forest-specialist performed well only in edge and forest. Most tadpoles occupying ephemeral pasture pools were facultative carnivores or cannibals of eggs and hatchlings. Tadpoles may contribute to the regulation of assemblages in pasture pools, influencing the relative abundance and composition of species through differential predation on eggs and hatchlings. The study of factors and mechanisms that contribute to population growth or decline of species can facilitate understanding of assemblage-level patterns of amphibian diversity in modified landscapes.

SAS has became an increasingly important public-health problem since 1970. It can adversely affect neurocognitive, cardiovascular, respiratory diseases and can also cause behavior disorder. Moreover, up to 90% of these cases are obstructive sleep apnea (OSA). Presently, Polysomnography is considered as the gold standard for diagnosing sleep apnea syndrome (SAS). However, Polysomnography-based sleep studies are expensive and time-consuming because they require overnight evaluation in sleep laboratories with dedicated systems and attending personnel. In this study, based on the nocturnal oxygen saturation (SpO2) signals, this work develops a method to classify patients with different levels of respiratory disturbance index (RDI) values. To achieve this goal, this study uses neural network in conjunction with different sets of feature variables to perform classification.

The current study investigated the relationship between obstructive sleep apnea (OSA) and depressive symptoms on neuropsychological functioning and academic achievement in a sample of ethnically diverse school-aged children in the Southwest United States. A total of 38 participants aged 6 - 12 were studied as part of an ongoing randomized clinical trial (SleepCATS) investigating the neurocognitive impact of continuous positive airway pressure therapy (CPAP) on neurobehavioral outcomes. Children were identified as having primary snoring, mild OSA, or Moderate-Severe OSA based on in-lab nocturnal polysomnography and were assessed for depressive symptoms using the parent report of the Child Behavior Checklist (CBCL). Neuropsychological testing was conducted using the Cambridge Automated Neuropsychological Test Battery (CANTAB) to assess executive functioning, working memory, and motor control. The Grooved Pegboard Test (GPT) was used to assess fine motor speed and dexterity and academic achievement was assessed on the Woodcock-Johnson Test of Academic Achievement Third Edition (WJ-ACH III). The study identified 39% of the sample as having clinical depressive symptoms and mean depressive symptoms for the sample was nearly one standard deviation above the norms. Multivariate analysis of covariance models (MANCOVA) were used to determine differences in neuropsychological test performance by neurocognitive constructs. Results from the study found significant main effects for OSA severity on the CANTAB Spatial Span Test and a significant interaction of off clinical depressive symptoms and OSA severity on the Applied Problems test of the WJ ACH III. When groups were compared between children with primary snoring and OSA (Mild and Moderate-Severe combined) there were no longer significant effects for academic achievement or working memory, however, there was a significant main effect for motor control on the CANTAB with children with OSA exhibiting lower performance compared to those with primary snoring. The results from this study suggest children with moderate-severe OSA may exhibit increased difficulties in working memory and fine-motor control, and also have increased difficulties with academic math achievement when children with moderate-severe OSA also have depressive symptoms. These findings suggest children with higher severities of OSA may experience increased learning and academic challenges, which may be further exacerbated when accompanied by depression.

Proefschrift Universiteit van Amsterdam. / Met lit. opg. - Met samenvatting in het Nederlands.