Of central importance to the study of heme proteins are the effects imposed by axial ligand(s) on the heme structure and, therefore, on the overall activity of the protein. In this study, we confirm and extend the spectroscopic characterization of a mutated sperm whale myoglobin in which the proximal Histidine is replaced with a Tyrosine residue (MbH93Y). The MbH93Y, as well as wild-type sperm whale myoglobin and horse erythrocyte catalase (HEC), was purified and characterized by optical absorption and x-ray absorption (XAS) spectroscopies. Optical absorption spectra of HEC and the metmyoglobin, cyanometmyoglobin, reduced, oxy, and carbon-monoxy forms of both sperm whale myoglobin (SWMb) and MbH93Y were identical to previously reported values within the respective errors:. Extended x-ray absorption fine structure (EXAFS) studies revealed that the proximal bond length in MbH93Y was 2.13 ± 0.03 A, compared to 2.14 ± 0.02 A for sperm whale metmyoglobin and 1.90 ± 0.02 A for catalase. Additionally, the sixth coordination site normally occupied in wild type sperm whale metmyoglobin and in catalase at low temperatures was vacant in MbH93Y, a result corroborated by the optical absorption spectra and cyanogen bromide modification of the distal histidine. Measurements were also made on the cyanide complexes of the three proteins as well, among which, (i) the average iron-to-pyrrole nitrogen bond distance for MbH93Y-CN was 1.96 ± 0.015 A compared to 2.00 ± 0.015 A for WT SWMb-CN and HEC-CN and (ii) the proximal bond length in MbH93Y-CN was 2.07 ± 0.02 A, while that of WT SWMb-CN was 2.10 ± 0.02 A and that of HEC-CN was found to be 2.12 ± 0.02 A. Further, upon exposure to 2-molar equivalents of hydrogen peroxide, sperm whale myoglobin formed a Compound II -like spectrum, while the Soret absorbance of MbH93Y was rapidly, significantly, and irreversibly decreased. Furthermore, the dissociation constants for CN- binding to MbH93Y were found to be, on average, approximately three orders of magnitude higher than those of wild-type sperm whale myoglobin and are consistent with the many-fold higher cyanide binding kinetics for wild type, relative to the mutant protein. Finally, the PK. of the mutant was found to be more than three orders of magnitude higher than that of the native protein. Explanations focusing on probable electronic effects of the phenolate oxygen atom in the sperm whale myoglobin pocket are discussed.

Indiana University-Purdue University Indianapolis (IUPUI) / Skeletal fractures due to bone disease impact an estimated 1.5 million Americans per year, creating a large economic burden on our society. Treatment of bone diseases prior to fracture often involves bisphosphonates (current gold-standard in osteoporosis care and prevention). Although bisphosphonates decrease fracture incidence, they often improve bone mass without regard for bone quality. Thus, although bisphosphonates increase the amount of bone present, the inherent bone material strength often decreases, creating a trade-off that increases the risk of atypical fractures after long-term use. This trade-off demonstrates the need for a treatment that targets both bone quality AND quantity. Although bone quality is important, the components of bone that contribute to bone quality are incompletely understood, making it difficult to create new pharmacological agents. With this in mind, my particular area of interest is in understanding how mechanical stimuli protects the formation of bone, leading to improved bone quality. Initially, this area was explored through use of tibial loading in a disease mouse model (osteolathyrism, induced by injection of beta-aminoproprionitrile) as a means of assessing how the body is able to compensate for decreased bone quality. The results of the BAPN and tibial loading studies indicated that injecting mice with BAPN may not be the ideal method to induce osteolathyrism. However, other intriguing results from the BAPN studies then led us into an exploration of how tibial loading itself contributes to bone quality.

Indiana University-Purdue University Indianapolis (IUPUI) / Raloxifene is an FDA-approved selective estrogen receptor modulator (SERM) that improves tissue quality by binding to collagen and increasing the bound water content in the bone matrix in a cell-independent manner. In this thesis, active tissue formation was induced by non-invasive external tibial loading in female mice and combined with raloxifene treatment to assess their combined effect on bone morphology and mechanical properties. Thermoregulation is an important factor that could have physiological consequences on research outcomes, and was introduced as an additional experimental factor in this study. We hypothesized that by removing the mild cold stress under which normal lab animals are housed, a metabolic boost would allow for further architectural and mechanical improvements as a result of the combination of tibial loading and raloxifene treatment. Ten week old female C57BL/6J mice were treated with raloxifene, underwent tibial loading to a strain level of 2050µε and were housed in thermoneutral conditions (32°C) for 6 weeks. We investigated bone morphology through microcomputed tomography (µCT) and mechanical properties via four-point bending and fracture toughness testing. Results indicated a combined improvement by external loading and raloxifene on geometry, particularly in the cancellous region of the bone, and also in bone mechanics leading to greater improvements than either treatment individually. Temperature did not have a robust impact on either bone architecture or mechanical integrity.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20388号 / 工博第4325号 / 新制||工||1670(附属図書館) / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 松原 誠二郎, 教授 吉田 潤一, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Kamouflagenät är ett viktigt verktyg inom försvarsindustrin där det används för att maskera eller dölja objekt från att bli visuellt upptäckta. Kamouflagenät är utformade för att efterlikna den omgivande miljön eller terräng som den appliceras vid. Traditionellt tillverkas kamouflagesystemen genom virkningsstekniken bi-axial varptrikå med två system inslagstrådar i 0° respektive 90°. För produktutvecklingens syfte att tillverka ett lätt kamouflagenät med lämpliga hållfasthetsegenskaper, undersöks tekniken multi-axial varptrikå med fyra system inslagstrådar i 0°, 90° och ±45°. Genom semi-strukturerade intervjuer med experter inom bi- och multi-axial varptrikå samlas det in information och fakta om multi-axial teknik. Detta fungerar som en grund för att avgöra om det är en möjlig teknik för den befintliga produkten. En teoretisk modellering utförs sedan för att undersöka, förutsäga samt jämföra beteenden och egenskaper hos de bi- och multi-axiella strukturerna. De semi-strukturerade intervjuerna resulterade i en omfattande och informativ faktainsamling om multi-axial teknik. Det inhämtades underlag gällande hur tillämpbar den multi-axiella tekniken är för kamouflagenät, samt information om maskinens begränsningar och trådorientering. Den teoretiska modelleringen innebär tillämpning av kända matematiska och fysikaliska begrepp, modelleringen lägger således en grund för att förstå mekaniska beteenden hos bi -och multi-axiella strukturer då de utsätts för små deformationer. Den teoretiska modelleringen resulterade i värden som beskriver styvheten hos de båda strukturerna vid deformationer på =0,01 i fyra riktningar. Kunskapen om lämpliga styvhetsegenskaper för kamouflagenät i kombination med resultatet från den teoretiska modelleringen lade en grund för att dra slutsatser om ifall multi-axiella strukturer, som är lika lätta som motsvarande bi-axiella strukturer vilka idag används i kamouflagenät, är lämpliga för att användas i kamouflagenät. Resultaten från modelleringen visar att de multi-axiella strukturerna i nästan samtliga fall har lägre elasticitetsmodul än deras motsvarande bi-axiella strukturer, detta innebär att det inte krävs lika stor kraft för att deformera de multi-axiella strukturerna. Modelleringen visar även att de båda strukturerna besitter olika egenskaper i olika riktningar, där de multi-axiella strukturerna beter sig likadant i alla fyra riktningar, till skillnad från de bi-axiella strukturerna som inte gör det. Enligt resultatet beror styvheten för de båda strukturerna på ett antal olika faktorer; trådtäthet, garnnummer och effektiv bredd, vilka appliceras som variabler i den teoretiska modelleringen. Modelleringen resulterade alltså därmed både till en förståelse för vilka faktorer som bidrar till skillnader i styvheten, och hur styvheten förhåller sig hos de båda strukturerna i olika riktningar. Studien visar att det i praktiken finns goda möjligheter för tillverkning av kamouflagenät i multi-axial varptrikå och att de multi-axiella strukturerna både kan göra kamouflagenäten mindre styva och bidra till isotropiska egenskaper. / Camouflage net is an essential device in the arms industry, where it is utilized to camouflage and hide objects from being visually detected. The camouflage net is designed to imitate the surrounding environment or terrain in which it is being applied. Traditionally, camouflage systems are manufactured using a knitting technique called bi-axial warp knitting with two systems of inlay yarns in 0° and 90° angles relative to the fabrics warp direction. To enhance the current product and produce light camouflage net with suitable strength properties, the multi-axial warp knitting technique with four systems of inlay yarns at 0°, 90° and ±45° angles is investigated. By utilizing semi-structured interviews with experts in the area of bi- and multi-axial warp knitting, can information and facts about multi-axial be collected and be used as a basis for concluding whether multi-axial is a suitable technique for the existing product. A theoretical modeling is then performed to examine, predict and compare the behaviors and properties of the bi- and multi-axial structures. The semi-structured interviews resulted in a comprehensive and informative collection of data about multi-axial technique. It also gathered information about the suitability and application of the technique to camouflage nets, as well as information regarding the machine’s limitations and thread orientation. The theoretical modeling involves the application of known mathematical and physical concepts, thus providing a foundation for understanding the mechanical behavior of bi- and multi-axial structures under small deformations. The theoretical modeling resulted in values that describe the stiffness of both structures at deformations of =0,01 in four directions. The knowledge of appropriate stiffness properties for camouflage nets, combined with the results from the theoretical modeling, laid the groundwork for drawing conclusions about the suitability of using multi-axial structures, which are as lightweight as the corresponding bi-axial structures currently used in camouflage nets. The modeling results show that the multi-axial structures generally have a lower initial modulus than their corresponding bi-axial structures, indicating that less force is required to deform the multi-axial structures. The modeling also reveals that the two structures exhibit different properties in different directions, with the multi-axial structures behaving similarly in all four directions, unlike the bi-axial structures. According to the results, the stiffness of both structures depends on several factors: thread density, yarn count, and effective width, which are applied as variables in the theoretical modeling. Thus, the modeling provides an understanding of the factors contributing to differences in stiffness and how the stiffness varies between the two structures in different directions. The study demonstrates that there are promising opportunities for manufacturing camouflage nets using multi-axial warp knit fabric in practice, and that the multi-axial structures can both reduce the stiffness of camouflage nets and contribute to isotropic properties.

Limonin and naringin are the two major bitter compounds in Citrus paradisi (grapefruit), and tissue-specific patterns on their distribution are well-established. This study was undertaken to determine the distribution of these compounds within Duncan, Marsh, and Thompson Pink tissues using three-dimensional fruit dissection (600-900 samples per fruit) and highly specific radioimmunoassays for limonin and naringin quantification. Results from a GLM ANOVA showed that there was no radial distribution pattern of limonin or naringin accumulation in these fruit. There were statistically significant differences in the axial distribution of these compounds within the fruit tissues. The limonin concentration in flavedo, albedo, outer segment memberane, and juice vesicles increased toward the distal end of the fruit. Naringin concentrations in flavedo, albedo, and outer segment membranes tended to be higher in the center portion of the fruit. Limonoate A-ring monolactone levels are also reported.

No description available.

No description available.

[pt] Consideramos neste trabalho a propagação de ondas magnetostáticas em cilindros de ferrite axialmente magnetizados, levando em conta a variação radial do campo interno de magnetização. O problema foi resolvido exatamente para campos não variáveis angularmente. Verificamos que as relações de disperção para o caso do campo de magnetização uniforme e o variável radialmente (foi considerada uma variação parabólica) somente coincidem para valores de freqüência bastante afastados da freqüência de ressonância. O fato de se considerar um campo de magnetização uniforme leva a resultados incorretos quando se consideram atrasos de pulsos de onda relativamente grandes. / [en] This work treats the propagation of magnetostatic waves in axially magnetized ferrite rods, taking into account the radial variation of the static magnetic field. An exact solution is found for no angular variation of the field. It is shown that only for frequencies sufficiently distant from resonance can the dispersion relation be the same for the cases of uniform magnetizing field and that of radially varying field (We considered a parabolic variation). The uniform magnetic field approximation leads to incorrect results when in the case of relatively large time delays.

The phenomena of stall and surge in axial-centrifugal compressors is investigated through high-response measurements of both the pressure field and the flowfield throughout the surge cycle. A unique high-response forward-facing and aft-facing probe provides flow information. Several axial-centrifugal compressors are examined, both in compressor rigs and engines. Extensive discussion is presented on the differences in axial and centrifugal rotors and their effect on the system response characteristics. The loading parameters of both are examined and data is presented that shows the increased tolerance of the centrifugal stage to instability. The dynamics of the compressor blade response are shown to be related to the transport time of a fluid particle moving through a blade passage. The data presented provides new insight into the dynamic interactions that occur prior to and during stall and surge. In addition, the inception of rotating stall and the inception of surge are shown to be the same phenomena . An analytical dynamic model (DYNTECC) is applied to one of the compression systems and the results are compared to data. The results show that the model can capture the global effects of rotating stall and surge. The data presented, along with the analytical results, provide useful information for the design of active and passive stall control systems. / Ph. D.