No description available.

No description available.

This thesis investigates the long-standing Abraham-Minkowski controversy concerning the momentum of light inside a dielectric medium. A revealing connection to the optical He-McKellar-Wilkens (HMW) phase is found upon studying the Langrangian describing the classical laser-atom interaction. This connection is further highlighted by moving into a semi-classical model in which the phase arises as a result of the transformation between the Abraham and Minkowski Hamiltonians. The HMW along with the Aharonov-Casher phases are found to be both dynamic and geometric depending on the representation. It is shown that an optical version of the HMW phase is acquired by a dipole moving in a laser beam, and I propose several interferometric schemes in order to observe the optical HMW effect. Finally, by moving into a cavity system, it is possible to account for the back action of the atoms on the light which changes the electromagnetic mode structure. This increase in model sophistication grants an alternative vantage from which to interpret the Abraham-Minkowski problem. / Thesis / Doctor of Philosophy (PhD)

Triticale belongs to the amphiploid cereals and was derived by crossing wheat and rye. Its baking quality is substantially worse than in wheat. The baking quality is determined by a composition and a content of the storage proteins. Both high and low molecular glutenin subunits have a major effect on the final quality of dough. The secalins of rye belong amongst the storage proteins of triticale, which negatively influence the baking quality. These are the reasons why lineages having translocated chromosome 1R and containing subunit Glu-D1d, which positively influences the baking quality, were created. The thesis is focused on identification of the allelic composition of loci of high molecular glutenin subunits (HMW-GS), low molecular glutenin subunits (LMW-GS), loci Pina a Pinb and null alleles of Waxy genes. 23 selected genotypes of triticale were analysed by using DNA markers based on polymerase chain reaction (PCR). Allelic composition of loci HMW-GS (Glu-A1, Glu-B1, Glu-D1), LMW-GS (Glu-A3) and Pina-D1, Pinb-D1 was described and null alleles were detected in the loci Wx-A1 and Wx-B1.

Master of Science / Food Science Institute, Agriculture / Katherine A. Tilley / Michael Tilley / The wheat tortilla is a chemically leavened circular light colored flat bread. Desirable characteristics for good quality tortilla include large diameter, softness, flexibility and long shelf stability. Important components influencing quality are wheat flour properties, which have not been optimized for tortilla industrial production thus far. The studies presented here investigated the effects of high molecular weight glutenin subunits (HMW-GS) on tortilla quality. Two approaches were employed: biotypes derived from Centurk and OK102 cultivars expressing defined HMW-GS compositions and transgenic wheat lines over-expressing HMW-GS 10. Analysis of protein expression and protein extractability were conducted to characterize wheat flours and suitable assays carried out to determine the respective dough properties. Tortillas were prepared by the hot-press method and quality parameters were measured at days 0, 2, 4, 7 and 14. Tortillas derived from Centurk biotypes possessing HMW-GS 2*, 7+9, 2+12, 2*, 7+8, 5+10 and 2*, 7+9, 5+10 exhibited superior texture profiles over time, but smaller diameters than the biotype 2*, 7+8, 2+12. Tortillas containing HMW-GS 7+9 and 2+12 revealed a texture profile similar to tortillas containing 5+10. Tortillas from the OK biotype 2*, 7+9, 3+12 exhibited larger diameter and texture profiles equivalent to tortillas containing 5+10. Therefore, this biotype showed the best quality within this cultivar. Tortillas derived from transgenic flours over-expressing HMW-GS 10 exhibited an undesirable rough appearance with decreased diameter, greater thickness, lower rollability scores, lower stretchability and greater rupture force over time. Over-expression of HMW-GS 10 in a wheat line containing 1RS-translocation did not promote the same deleterious effects in tortilla quality as it did in transgenic lines without 1RS translocation.

No description available.

Permafrost soils in the Arctic store large quantities of organic matter, roughly twice the amount of carbon that was present in the atmosphere before the industrial revolution. This freeze-locked carbon pool is susceptible to thawing caused by amplified global warming at high latitudes. The remobilization of old permafrost carbon facilitates its degradation to carbon dioxide and methane, thereby providing a positive feedback to climate change. Accelerating coastal erosion in addition to projected rising river discharge with enhancing sediment loads are anticipated to transport increasing amounts of land-derived organic carbon (OC) to the Arctic Ocean. On its shallow continental shelves, this material may be remineralized in the water column or in the sediments, transported without being altered off shelf towards the deep sea of the Arctic Interior or buried in marine sediments and hence sequestered from the contemporary carbon cycle. The fate of terrigenous material in the marine environment, though offering potentially important mechanisms to either strengthen or attenuate the permafrost-carbon climate feedback, is so far insufficiently understood. In this doctoral thesis, sediments from the wide East Siberian Arctic Shelf, the world’s largest shelf-sea system, were used to investigate some of the key processes for OC cycling. A range of bulk sediment properties, carbon isotopes and molecular markers were employed to elucidate the relative importance of different organic matter sources, the role of cross-shelf transport and the relevance of degradation during transport and after burial. Overall, OC released from thawing permafrost constitutes a significant proportion of the sedimentary organic matter on the East Siberian Arctic Shelf. Two sediment cores from the inner and outer East Siberian Sea recorded no substantial changes in source material or clear trends in degradation status for the last century. With increasing distance from the coast, however, strong gradients were detected towards lower concentrations of increasingly reworked land-derived OC. The time spent during cross-shelf transport was consequently found to exert first-order control on degradation. Compound-specific radiocarbon dating on terrigenous biomarkers revealed a net transport time of ~4 000 years across the 600 km wide Laptev Sea shelf, yielding degradation rate constants for bulk terrigenous OC and specific biomarkers on the order of 2-4 kyr-1. From these results, the carbon flux released by degradation of terrigenous OC in surface sediments was estimated to be ~1.7 Gg yr-1, several orders of magnitude lower than what had been quantified earlier for dissolved and particulate OC in the water column. Lower oxygen availability and close associations with the mineral matrix may protect sedimentary OC from remineralization and thereby weaken the permafrost-carbon feedback to present climate change. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.</p>

Adiponectin is an adipose-derived protein (adipocytokine) that is secreted by adipose tissue. It has insulin-sensitizing, anti-inflammatory and cardio-protective properties, and is thought to be protective against obesity-related diseases such as type 2 diabetes. Humans and cats are two species that commonly develop type 2 diabetes associated with insulin resistance, impaired beta cell function and spontaneous islet amyloid deposition. The domestic cat (Felis catus) has recently been proposed as an animal model for human type 2 diabetes. However, little is known about the physiology of adiponectin in cats. Therefore, we set out to investigate the association of adiponectin profiles with dietary carbohydrate intake, feeding, body weight, fat mass, and insulin sensitivity in healthy young adult cats (n=32; 2-4 years old; gender ratio 1:1; body condition 4-5/9). Cats were fed a moderate carbohydrate diet (37% ME) at maintenance energy requirements for four weeks. Cats were then assigned to either receive a low (19% ME) or high (52% ME) carbohydrate diet and fed at maintenance energy requirements for another four weeks, followed by ad-libitum feeding for eight weeks to facilitate weight gain. Adiponectin profiles including total circulating adiponectin and its distribution [low molecular weight (LMW) and high molecular weight (HMW) adiponectin], and proportion of adiponectin that is HMW (SA) were measured by ELISA and velocity sedimentation using sucrose gradients, followed by Western blotting, respectively. We demonstrated inter-animal variation in total adiponectin concentration at baseline (0.6 to 15.0 g/mL), with the adiponectin present in both LMW and HMW forms. Feeding with a high carbohydrate diet for four weeks at maintenance energy requirements resulted in increased total adiponectin concentration, which was associated with an increased concentration of LMW adiponectin. In contrast, feeding with a low carbohydrate diet for four weeks at maintenance energy requirements resulted in increased concentration of HMW adiponectin, decreased LMW adiponectin concentration, and increased SA, without a change in total adiponectin concentration. In cats fed the high carbohydrate diet, total adiponectin and HMW adiponectin concentrations become lower at six hours after feeding, as compared to the fasting concentrations. This phenomenon was not observed in cats fed a low carbohydrate diet, indicating a diet-dependent postprandial effect. There was no effect of gender on any of the adiponectin profiles in cats. Unlike other studies in humans and mice in which adiponectin concentrations decreased as fat mass increased, our data indicate that a moderate weight gain achieved by ad libitum feeding of a low carbohydrate diet for eight weeks correlated with increased adiponectin concentrations. Total adiponectin concentration (mirrored by HMW adiponectin) was positively correlated with body weight gain and fat mass gain (but not absolute fat mass) in our overweight cats. Furthermore, the fat mass-related increases in plasma adiponectin over eight weeks correlated with insulin sensitivity (higher adiponectin concentration corresponded to greater insulin sensitivity in overweight cats). These data hint at the possibility that in overweight animals, adiponectin is similar to other adipokines that rise concomitantly with increased of moderate fat mass gain and thus increases insulin sensitivity. Overall, the knowledge in this study therefore provides useful information to veterinarians and cat food manufacturers, and forms a foundation for future studies to extend our knowledge of adiponectin in cats. Data gathered in cats may also be applicable to humans and could therefore inform research using cats as an animal model of human obesity and type 2 diabetes.

Adiponectin is an adipose-derived protein (adipocytokine) that is secreted by adipose tissue. It has insulin-sensitizing, anti-inflammatory and cardio-protective properties, and is thought to be protective against obesity-related diseases such as type 2 diabetes. Humans and cats are two species that commonly develop type 2 diabetes associated with insulin resistance, impaired beta cell function and spontaneous islet amyloid deposition. The domestic cat (Felis catus) has recently been proposed as an animal model for human type 2 diabetes. However, little is known about the physiology of adiponectin in cats. Therefore, we set out to investigate the association of adiponectin profiles with dietary carbohydrate intake, feeding, body weight, fat mass, and insulin sensitivity in healthy young adult cats (n=32; 2-4 years old; gender ratio 1:1; body condition 4-5/9). Cats were fed a moderate carbohydrate diet (37% ME) at maintenance energy requirements for four weeks. Cats were then assigned to either receive a low (19% ME) or high (52% ME) carbohydrate diet and fed at maintenance energy requirements for another four weeks, followed by ad-libitum feeding for eight weeks to facilitate weight gain. Adiponectin profiles including total circulating adiponectin and its distribution [low molecular weight (LMW) and high molecular weight (HMW) adiponectin], and proportion of adiponectin that is HMW (SA) were measured by ELISA and velocity sedimentation using sucrose gradients, followed by Western blotting, respectively. We demonstrated inter-animal variation in total adiponectin concentration at baseline (0.6 to 15.0 g/mL), with the adiponectin present in both LMW and HMW forms. Feeding with a high carbohydrate diet for four weeks at maintenance energy requirements resulted in increased total adiponectin concentration, which was associated with an increased concentration of LMW adiponectin. In contrast, feeding with a low carbohydrate diet for four weeks at maintenance energy requirements resulted in increased concentration of HMW adiponectin, decreased LMW adiponectin concentration, and increased SA, without a change in total adiponectin concentration. In cats fed the high carbohydrate diet, total adiponectin and HMW adiponectin concentrations become lower at six hours after feeding, as compared to the fasting concentrations. This phenomenon was not observed in cats fed a low carbohydrate diet, indicating a diet-dependent postprandial effect. There was no effect of gender on any of the adiponectin profiles in cats. Unlike other studies in humans and mice in which adiponectin concentrations decreased as fat mass increased, our data indicate that a moderate weight gain achieved by ad libitum feeding of a low carbohydrate diet for eight weeks correlated with increased adiponectin concentrations. Total adiponectin concentration (mirrored by HMW adiponectin) was positively correlated with body weight gain and fat mass gain (but not absolute fat mass) in our overweight cats. Furthermore, the fat mass-related increases in plasma adiponectin over eight weeks correlated with insulin sensitivity (higher adiponectin concentration corresponded to greater insulin sensitivity in overweight cats). These data hint at the possibility that in overweight animals, adiponectin is similar to other adipokines that rise concomitantly with increased of moderate fat mass gain and thus increases insulin sensitivity. Overall, the knowledge in this study therefore provides useful information to veterinarians and cat food manufacturers, and forms a foundation for future studies to extend our knowledge of adiponectin in cats. Data gathered in cats may also be applicable to humans and could therefore inform research using cats as an animal model of human obesity and type 2 diabetes.

Tortilla sales are projected to exceed 9.5 billion by 2014. However, currently no wheat cultivars have been identified that possess the intrinsic quality attributes needed for the production of optimum quality tortillas. Tortillas made with refined wheat flour low in dietary fiber (DF) are popular in the United States due to their sensory properties. This study explored the use of wheat lines (WL) possessing variations in high molecular weight glutenin allele sub-units (HMW-GS) for production of tortillas and also investigated the use of corn based resistant starches (RS), type II (RS2) and wheat based RS type IV (RS4) to increase DF in tortillas. Tortillas were made with 0-15 percent RS and 100 percent whole white wheat (WW). Flour protein profiles, dough, and tortilla properties were evaluated to determine the effects of the allelic variations and RS substitution on tortilla quality. Sensory properties of tortillas with RS were determined. Variations in HMW-GS composition significantly affected the protein quality and tortilla properties. Flour from WL possessing allelic combinations (2*, 17+18, 7, 2+12), (1, 17+18, 5+10), (2*, 17, 2+12) and (1, 2*, 17+18, 2+12) had 12.8-13.3 percent protein. These WL had extensible doughs and produced large diameter tortillas with superior (greater than or equal to 3.0) flexibility after 16 days compared to control. However, WL with (17+18 and 5+10) and (2*, 17+7, 5) produced extensible doughs, large, but less flexible, tortillas compared to control. WL with (2*,17+18,5+10) and (1,2*,7+9,5+10) produced smaller diameter tortillas, but with superior flexibility compared to control. RS2, WW, and cross-linked-pre-gelatinized RS4 (FiberRite) produced hard, less-extensible doughs and thinner tortillas compared to control, due to high water absorption. Cross-linked RS4 (Fibersym) dough and tortillas were comparable to control. 15 percent of RS2 and RS4 increase DF in control to 6 and 14 percent respectively, compare to control (2.8 percent DF). WW tortillas were less acceptable than control in appearance, flavor and texture, while tortillas with 15 percent Fibersym had higher overall acceptability than control. RS2 negatively affected dough machinability and tortilla shelf stability. However, 15 percent RS4 improved the DF in refined flour tortillas to meet FDA's "good source of fiber claim," without negatively affecting dough/tortilla quality.