Real-time or quantitative PCR (qPCR) is an innovative method used to determine the amount of amplifiable DNA in a biological sample. Typically, a fluorescent dye is introduced during thermal cycling, causing a change in fluorescent output as the double-stranded DNA (dsDNA) product accumulates. Both TaqMan® and Plexor HY System methods detect PCR inhibition through the monitoring of internal control sequences. Alternatively, SYBR®Green and Plexor detect inhibition through melt curve effects. Previous work using SYBR®Green intercalation has demonstrated that inhibitors can affect melt curves differently depending on their structure and mode of action. Inhibitors that bind DNA can cause melt curve shifts while those primarily affecting Taq polymerase do not. Unlike SYBR®Green, Plexor dyes are fluorescently linked to a modified base, 5'-methylisocytosine (iso-dC), adjacent to the 5' end of the dsDNA. This produces minimal interference in dsDNA structure making it an ideal procedure for measuring these effects. In this study, inhibition of qPCR was evaluated by observing the effects of various inhibitor concentrations and amplicon lengths on DNA amplification.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22474号 / 工博第4735号 / 新制||工||1740(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 山本 量一, 教授 渡辺 宏, 准教授 谷口 貴志 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

L’objectif général de cette thèse était d’identifier les mécanismes moléculaires du frottement d’un fluide de polymère sur une surface solide à partir de l’écart à la condition de vitesse nulle à la paroi.La première partie de cette thèse a consisté à développer une nouvelle méthode de mesure du glissement des liquides de polymère par suivi d’un motif photolysé dans un fluide fluorescent. Cette méthode, qui est une évolution de celle utilisée précédemment dans le groupe, donne directement accès au champ de déplacement du fluide lors de l’écoulement. À l’aide de ce nouveau dispositif, nous avons étudié expérimentalement l’effet de la nature de la surface, de la viscosité du liquide et de la température sur le glissement de fondus de polymère (T>Tg). Il est apparu que l’effet de glissement est contrôlé par la viscosité des fondus et par un coefficient de frottement à l’interface qui ne dépend que des natures moléculaires du liquide et de la surface. En particulier, ce coefficient de frottement est le même pour un fondu ou pour un élastomère constitué du même polymère. La dépendance en température de cet effet est fixé par la différence des énergies d’activation des processus activés que sont la viscosité du liquide et le frottement sur la surface solide. Nous avons également étudié le cas des solutions concentrées de polymère pour lesquelles le mécanisme du frottement est différent. En effet nous avons montré que le coefficient de frottement n’est plus une grandeur locale et dépend de la concentration de la solution. Enfin nous nous sommes intéressés à l’évolution temporelle de la transition de glissement dans les fondus et les solutions causée par la présence de chaînes de polymère adsorbées sur les parois. / The goal of this work was to identify the molecular mechanisms governing the friction of a polymeric liquid on a solid surface by studying the deviation from the no-slip boundary condition.First, we developed a new method of measurement of slip of a polymeric liquid based on the observation under shear of a pattern photobleached in a fluorescent fluid. This method, which is an evolution of one already used in the group, give a direct access to the displacement field of the liquid under shear. Using this setup, we studied experimentally the effect of the chemical nature of the surface, of the liquid viscosity and of the temperature on the slip of polymer melt (T>Tg). It appeared that the slip effect is governed by the viscosity of the liquid and a friction coefficient which depends only on the chemical natures of the liquid and the surface. In particular this coefficient is the same for a melt and for an elastomer made of the same polymer. The temperature dependence of this effect is characterized by the difference of activation energy of viscosity of the liquid and of the friction on the solid surface that both are activated processes. We also studied the case of concentrated polymer solutions for which the molecular mechanism of friction differs. Indeed we showed that the friction coefficient is no longer a local quantity and depends on the concentration. Finally, we investigated the evolution over time of the slip transition of polymer melts and solutions which is due to the adsorption of polymer chains on the solid walls.

Sea-level fingerprints, the spatial patterns of sea level change resulting from rapid melting of glaciers and ice sheets, play an important role in understanding past and projecting future changes in relative sea level (RSL). Over century timescales, the viscous flow of Earth’s interior is a small component of the total deformation due to ice loading in most regions, so fingerprints computed using elastic Earth models are accurate. However, in regions where the viscosity is orders of magnitude lower than the global average, the viscous component of deformation can be significant, in which case it is important to consider models of viscoelastic deformation. There is evidence that the glaciated regions of Alaska, Western Canada and USA, and the Southern Andes are situated on top of mantle regions in which the local viscosity is several orders of magnitude lower than typical global mean values. The goal of this work is to determine the importance of viscous flow in computing RSL fingerprints associated with future ice mass loss from these regions. Version 5.0 of the Randolph Glacier Inventory is used to estimate the ice load distribution required for calculating sea-level fingerprints. For the glaciated regions that have lower than average viscosity, fingerprints were calculated using an elastic Earth model and a 3D viscoelastic model to quantify the influence of viscous flow on the predicted sea level changes. Using glacier mass loss values for the intermediate future climate scenario Representative Concentration Pathway (RCP) 4.5, the global sea level response was computed at 2100 CE relative to 2010 CE due to melting from all glacier regions. On comparing the results of the two models it was found that ice-load-induced viscous flow contributes significantly (more than a few cm) to the RSL fingerprints only in near-field regions. However, in these regions, the non-elastic contribution can be 10s of cm. For example, at Juneau, USA the elastic calculation gave relative sea level changes of ∼ −45 cm, compared to ∼ −120 cm based on the viscoelastic calculation.

The work herein covers the complete process for development, production and testing of a melt processable pyrotechnic composition, with the goal of using the composition as a printing material in a fused deposition modelling (FDM) type 3D printer. 3D printing is fast becoming an area of interest for energetic materials research. This is due to the role that geometry can play in combustion performance of a composition and 3D printing’s ability to produce a variety of complex designs. Melt processable fluoropolymers were selected as oxidisers. The polymers selected for the study were FK-800® and Dyneon 31508®. Both are co-polymers of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE). Aluminium was the choice fuel in this instance as it had better energetic performance than the alternatives investigated. It was also deemed to be a safer fuel when considering the combustion products. Hazardous combustion products like hydrofluoric and hydrochloric acid could be suppressed by increasing the fuel loading to 30 wt.%, thereby reducing the risks associated with burning the composition. Preliminary differential thermal analysis (DTA) analysis indicated that the compositions would only ignite above 400 °C which was well above the suggested processing temperature of 230 °C as determined from thermogravimetric (TGA) analysis. These thermal analysis techniques indicated that the reactions were most likely a gas-solid reactions due to ignition temperatures being significantly lower than those associated with phase changes occurring in the fuels tested, yet above the decomposition temperatures for the oxidisers. ii Extrusion of the compositions proceeded with addition of LFC-1® liquid fluoroelastomer. This addition was made in order to order to lower the melt viscosity, thereby improving the quality of the filament produced. Compositions were extruded with an aluminium loading of 30 wt.%. Oxidiser and LFC-1® made up the rest of the mass with the LFC-1® contributions being either 7 wt.% or 14 wt.%. Burn rates, temperatures and ignition delays were all influenced by the addition of LFC-1® to the system. FK-800® was found to be a better oxidiser in this instance since its burn rates were consistent especially when compared to erratic nature of the Dyneon 31508® burns. Linear burn rates for the FK-800® increased from 15.9 mm·s−1 to 18.9 mm·s−1 with the increase in LFC-1® loading. Combustion temperature also increased by approximately 180 °C from 794 °C. Printing with the material was achieved only after significant alterations were made to the hot end used. Printing proceeded in a staged, start-stop manner. After each new layer of material was deposited the printer was cleared of material and the hot end was allowed to cool. If this procedure was not followed it led to significant preheating of the material within the feeding section of the extruder. This premature heating caused feeding problems due to softening and swelling of the material within the cold side of the hot end which led to blockages, leading to the conclusion that the composition was not compatible with the off-the-shelf hot end used in this study. Low quality printing could be achieved with both FK-800® and Dyneon 31508® compositions. This would suggest that slight compositional changes paired with the alterations made to the hot end could improve the quality of the prints to an extent that would be comparable to that of more commonplace printing materials. / Dissertation (MEng)--University of Pretoria, 2017. / Chemical Engineering / MEng / Unrestricted

This work was concerned with evaluating the behavior of thermoplastics reinforced with melt processable phosphate glasses processed by techniques including injection molding, compression molding, and thermoforming. Thermoplastic resins consisting of polyphenylene sulfide (PPS), polyetherimide (PEI) and polyetheretherketone (PEEK) were combined with phosphate glasses having glass transition temperatures (Tg) that ranged from 230-290°C to form composite systems where both the matrix and reinforcing phase were deformable during processing. For the process of injection molding, several factors were examined to maximize the mechanical properties obtained with the addition of the phosphate glasses. The influence of variables such as the glass and matrix viscosity, glass loading, melt temperature, and mold fill rate were examined for a variety of composite blends consisting of the PPS, PEI, and PEEK reinforced with a lower Tg (234°C) phosphate glass and PEEK blended with a higher Tg (282°C) glass. From this work, it was determined that the best mechanical properties were generally produced by using processing temperatures and material combinations that minimized the viscosity differences between the thermoplastic resin and phosphate glass. Variations in the material combinations and processing conditions utilized were also found to result in the formation of a variety of glass phase morphologies that consisted of droplets, ribbons, and an interpenetrating network structure. The addition of the phosphate glass to the neat thermoplastics resins was found to be an effective way to produce injection moldable composite blends. The stiffness of the composite blends increased with glass loading with composites containing up to 45 vol% phosphate glass exhibiting machine direction tensile and flexural moduli in the range of 3-5 times greater than that those of the neat thermoplastics. Additionally, these composites were found to offer moduli and strengths that ranged from 25-50% lower than conventional E-glass fiber reinforced materials of the same loading. The lower mechanical properties of the neat phosphate glasses coupled with a lack of adhesion between the matrices and the glasses helped contribute to the lower mechanical properties exhibited by the phosphate glass reinforced composites. Still, the phosphate glass reinforced blends offered certain advantages including lower mechanical anisotropy, smoother surfaces, and lower viscosities. The processing behavior of phosphate glass reinforced thermoplastics was also examined at temperatures commonly used in forming and shaping operations such as compression molding and thermoforming. It was determined that it was possible to deform the phosphate glass reinforcing phase along with the matrix resin at temperatures only 30-50°C above the Tg of the glass. The deformable phosphate glass reinforcing phase resulted in composite blends that exhibited greater extensibility than a solid E-glass fiber reinforced material. The elongation of the phosphate glass into a higher aspect ratio reinforcing morphology was found to result in an almost 25% increase in the tensile modulus for a polyphenylene sulfide based composite. / Ph. D.

Indiana University-Purdue University Indianapolis (IUPUI) / Observations of heterogeneities in Earth’s mantle motivate studies of mantle phase assemblages with variable composition. As samples cannot be directly collected from these regions, synthetic glasses can act as analogues for mantle melt and starting materials for high-pressure synthesis of stable mantle minerals in experiments. Here, I develop a specific methodology to produce homogeneous glasses that accurately span the composition space from enstatite (MgSiO3) to forsterite (Mg2SiO4), as well as Fe-bearing enstatite ((Mg0.1Fe0.9)SiO3 and ((Mg0.95Fe0.05)(Si0.95Fe0.05)O3) with variable oxidation states. This study systematically tests and iterates upon glass synthesis methods using an aerodynamic levitation laser furnace, in which a spherical glass sample levitates on a gas stream flowing vertically through a conical nozzle, while being heated from above with a 400 W CO2 laser. With sample diameters of 0.6-2.0 mm, shutting off the laser results in supercooling of levitated spheres at rates between 350 and 1350 °C/s. Sample preparation begins with grinding and mixing pure oxide powders in an agate mortar and pestle, followed by heating in a high temperature oven to devolatilize the mixture. Powders (0.5-7 mg aliquots) are fused into spheres in a copper hearth plate. To tune Fe valency and vitrify each sphere, samples are then levitated on flows of Ar, O2, 5% CO in Ar, 5% CO2 in Ar, or combinations of two of these gases, while being heated with the laser to temperatures above the liquidus for each composition for ~10 s before quenching. After x-ray diffraction (XRD) analyses confirm vitrification, a dual polish is applied, exposing parallel flat polished surfaces for scanning electron microscope (SEM) and electron probe microanalyzer analyses (EPMA). Back-scattered electron images and energy-dispersive x-ray spectroscopy (EDS) analyses of the spheres are obtained first on the SEM to gauge compositional accuracy and homogeneity, then EPMA analyses determine quantitatively the samples’ compositions. Once fully characterized, these glasses can be used in diamond anvil cell experiments, where they can act as proxies for an otherwise inaccessible area of the Earth. In addition to the development of this methodology, two web applications produced during this research aid in visualization of both data logs and analytical results.

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

No description available.

Quantifying the contribution of glaciers to water resources is particularly important in locations where glaciers may provide a large percentage of total river discharge. In some remote locations, direct field measurements of melt rates are difficult to acquire, so alternate approaches are needed. Positive degree-day modeling (PDD) of glacier melt is a valuable tool to making first order approximations of the volume of melt coming from glaciers. In this study, a PDD-melt model is applied to glaciers in the Indus River watershed located in Afghanistan, China, India, and Pakistan. Here, millions of people rely on the water from the Indus River, which previous work suggests may be heavily dependent on glacier melt from high mountain regions in the northern part of the watershed. In this region, the PDD melt model calculates the range of melt volumes from more than 45,000 km2 of glaciated area. It relies on a limited suite of input variables for glaciers in the region: elevation, temperature, temperature lapse rate, melt factor, and surface area. Three global gridded climate datasets were used to determine the bounds of temperature at each glacier: UEA CRU CL 2.0, UEA CRU TS 2.1, and NCEP/NCAR 40 year reanalysis. The PDD melt model was run using four different melt scenarios: mean, minimum, maximum, and randomized. These scenarios account for differences in melt volume not captured by temperature, and take uncertainties in all input parameters into account to bound the possible melt volume. The spread in total melt volume from the model scenarios ranges between 27 km3 and 439 km3. While the difference in these calculations is large, it is highly likely the real value falls within this range. Importantly, even the smallest model volume output is a significant melt water value. This suggests that even when forcing the absolute smallest volume of melt, the glacier contribution to the Indus watershed is significant. In addition to providing information about melt volume, this model helps to highlight glaciers with the greatest contribution to total melt. Despite differences in the individual climate models, the spatial pattern in glacier melt is similar, with glaciers contributing the majority of total melt volume occurring in similar geographic regions regardless of which temperature dataset is used. For regions where glacier areas are reasonably well-constrained, contributions from individual glaciers can be quantified. Importantly, less than 5% of glaciers contribute at least 70% of the total melt volume in the watershed. The majority of these glaciers are in Pakistan, the region with the largest percentage of known glaciers with large surface areas at lower elevations. In addition to calculating current melt volumes over large glaciated areas, this model can also be used to determine future melt rates under differing climate scenarios. By applying suggested future regional temperature change to the temperature data, the impact on average melt rate over the watershed was found to increase from 3.02 m/year to 4.69 m/year with up to 2 °C temperature increase. Assuming glacier area remains relatively constant over short time periods, this would amount to a 145 km3 increase in melt volume.