Phreatic and hydrothermal eruptions often occur with little or no warning representing a significant hazard within geothermal regions. These violent eruptions occur at a range of temperatures and pressures within varying rock types. A range of mechanisms including heating or decompression, allows hydrothermal/supercritical fluid to rapidly flash to steam, expanding and shattering the surrounding rock to produce an eruption, with no direct magmatic influence. These eruptions are highly variable resulting in the current wide ranging classification schemes, many of which are based on characteristics that are hard to observe and define. This has resulted in confusing nomenclature with many different terms used to describe the same eruptive phenomena. Here a new classification scheme is presented, based on the easily definable features of eruption size, trigger type (natural or anthropogenic) and geological setting (volcanic or hydrothermal). This ultimately produces a classification dividing the eruptions into either phreatic, where magma interacts with cold water but no juvenile material is erupted; or hydrothermal where eruption occurs from an already heated hydrothermal system. Examples are then provided for each classification type. Previous studies have focused exclusively on either physical characteristics of eruptions, small scale experimental modelling of trigger processes or mathematical modelling of various eruption characteristics. Here, a new experimental procedure has been developed to model phreatic fragmentation, based on shock tube experiments for magmatic fragmentation by Alidibirov and Dingwell (1996). Water saturated samples are fragmented from a combination of argon gas overpressure and steam flashing within vesicles. In this thesis, these experimental results have been integrated with the physical characteristics of porosity, permeability and mineralogy to create two new models of phreatic fragmentation. Firstly a generalised model to explain fragmentation processes and secondly a specific model describing the eruption forming Lake Okaro, within the Taupo Volcanic Zone of New Zealand. These models were developed with the overall aim to improve understanding of these eruption types, ultimately improving future hazard modelling. Experiments were performed on Rangitaiki ignimbrite, through which the Okaro eruption occurred. In order to evaluate alteration effects, both unaltered ignimbrite and hydrothermally altered ignimbrite samples were analysed. Experiments were performed at room temperature and 300°C with pressures from 4 to 15 MPa, to reflect likely geothermal conditions while also assessing the effect of liquid water on fragmentation. Results indicate that within these samples 5 to 8 MPa of decompression is required to trigger an eruption, fitting well with the previously identified trend between decompression and porosity for magmatic samples. The fragmentation front propagates through the sample at speeds ranging between 14 m/s to 42 m/s, increasing with higher applied pressures and higher sample porosity. Most importantly, grain size analysis from these experiments show a clear shift to smaller grain sizes when liquid water flashes to steam (independent of pressure or sample type), reflecting the greater energy involved with steam flashing. Previous grain size analysis of the Okaro breccia deposits have indicated that the highest weight percentage of fragments fall between -3.5 and 1.5 phi, with our experimentally produced fragments fitting right within this range at -0.5 to 1.0 phi. Here the first parameterisation of conditions for phreatic and hydrothermal eruptions is presented creating a general fragmentation model along with a case study on Lake Okaro. These models describe how eruptions occur, with stages from initial system priming and overpressure development through to the last stages of eruption and crater formation.

This thesis presents a study of three electrochemical methods applied to the fragmentation of proteins. Direct electrochemical oxidation at graphite electrodes, production of hydroxyl radicals on lead dioxide electrodes and electro-Fenton methods were each investigated as methods for fragmenting proteins. A key objective of this project was to achieve specific fragmentation, meaning that fragmentation would only occur at defined sites on each protein molecule and that this process may provide a new pathway to producing useful protein fragments. Protein fragments produced by electrochemical means were detected using mass spectroscopy and gel electrophoresis techniques. Direct electrochemical oxidation of the target proteins was studied at a graphite rod electrode in a solution containing acetonitrile, water and formic acid. β-lactoglobulin fragmentation was detected by mass spectroscopy, but fragmentation did not occur to an extent where fragments were observable by gel electrophoresis. It was evident that most of the electrolysis products appear to arise from non-cleavage oxidation reactions. The use of lead dioxide electrodes to generate hydroxyl radicals was thoroughly investigated in this work. For the first time, specific fragmentation of proteins has been achieved by direct electrochemical generation of hydroxyl radicals on the electrode surface. The pH and the chemical composition of the protein solutions were found have a strong influence on the extent of fragmentation. Electro-Fenton chemistry was conducted on a woven carbon fibre electrode. The electrode successfully reduced dissolved oxygen to produce hydrogen peroxide and regenerated Fe(II) from Fe(III). Cell conditions were optimized for applied current, method of oxygen delivery and cell division. The Fenton reaction between hydrogen peroxide and Fe(II) produced hydroxyl radicals that were able to specifically fragment proteins. It was not possible to increase the concentration of these protein fragments by increasing the hydrogen peroxide concentration, as the fragmentation products were also further fragmented. Electrochemical protein fragmentation was achieved in all three electrochemical systems, however the most promising results were achieved by electrochemical generation of hydroxyl radicals on a lead dioxide electrode. This work has the potential to become a fast and cost effective method for the fragmentation of proteins required for nutrition and medical purposes or for use in protein identification analysis with mass spectroscopy.

No description available.

Human activities that lead to fragmentation and habitat loss are big problems in the world. Due to global climate change the negative effects of fragmented habitats can be catastrophic for many organisms. In the Amazon rainforest, that is most sensitive to human impact, stands a big risk to lose its species diversity. Fragmentation and climate change together seems to escalate the death rate of rainforest plants and that will change the whole ecosystem. Birds and insects are depending on the trees and the trees faces big challenges now. Many of the rainforest organisms have been noticed to emigrate further up to northern altitudes due to the warmer climate and maybe also because of deforestation. Many of the lowland forest birds are predicted to distribute from their origin habitats. The national reserve Allpahuayo Mishana in the Peruvian Amazon is known for its diversity of birds. It is a big challenge for the reserve to maintain the origin forest composition from climate change, which will lead to losses of species. The reserve allows the local community to utilize the land for small-scale uses inside the protected zone. Many of the birds are sensitive for external disturbance. Most human activities are resulting in that the forest becomes less dense, which can lead to that the territory for the birds decreases. This makes it important for the reserve to improve the human land use not to restrict the birds' habitat inside the reserve. This project will investigate if the small-scale land uses affects the understory birds’ diversity and habitat negative. The purpose is to see if the fragmented forests in the reserve, closest to the utilized land, can functioning as a secondary forest for the understory birds, or are the understory birds limited by the small-scale land use, in the national reserve Allpahuayo Mishana? Four sites with various human activities were chosen to investigate if the sites contain any understory birds. The result showed that the most disturbed sites had poor bird diversity compare to the sites with no human disturbance.

Curcumin analogues are novel antineoplastic agents designed by structural modifications of the natural product curcumin to enhance its therapeutic effects. Various curcumin analogues displayed a significant cytotoxic effect towards different cancer cell lines including leukemia, melanoma, and colon cancer. In order to evaluate the safety, efficiency and metabolism of the new anticancer candidates, sensitive and high throughput analytical methods are needed. Thirteen curcumin analogues with the backbone structure of 3,5-bis(benzylidene)-4-piperidone were tested. The ionization behavior of curcumin analogues was investigated to reveal the possible mechanisms for the unusual formation of the positively charged [M-H]+ ions during single stage positive ion mode MALDI-MS analysis. Different ionization techniques (i.e., ESI, APCI, APPI, and MALDI) were used to evaluate this phenomenon. The results showed that curcumin analogues ionize into [M-H]+ along with the expected [M+H]+ species during MALDI and dopant free APPI-MS. In contrast, ESI, APCI and the dopant mediated APPI showed only the expected [M+H]+ peak. Our experiments revealed that photon energy triggers the ionization of the curcumin analogues even in the absence of any ionization enhancer such as matrix, solvent or dopant. Three proposed mechanisms for the formation of [M-H]+ were evaluated, two of them are probably involved in the [M-H]+ formation: (i) hydrogen transfer from the analyte radical cation and (ii) hydride abstraction. In addition to the ionization behavior, the collision induced dissociation-tandem mass spectrometric (CID-MS/MS) fragmentation behavior of curcumin analogues was evaluated showing similar dissociation pathways that centered on the piperidone ring of the 3,5-bis(benzylidene)-4-piperidone moiety. The presence of different substitutes on that moiety resulted in specific product ions for each curcumin analogue. The fragmentation patterns were established to confirm the chemical structure of the tested compounds and identify the diagnostic product ions of each compound. Twelve common product ions were identified resulting from the breakage of various bonds within the piperidone moiety. There was a tendency for the formation of highly conjugated product ions that are stabilized via resonance. Common product ions were identified allowing for the establishment of a general MS/MS behavior for any curcumin analogue that belongs to the 3,5-bis(benzylidene)-4-piperidone structural family. The fragmentation routes and the genesis of the product ions were confirmed via MS3 and neutral loss analysis. In summary, the ionization of curcumin analogues provided insights into the formation of unique [M-H]+ ions which were linked to photo ionization of such compounds without the need for additives, such as matrix, dopant or solvent. As such, curcumin analogues should be evaluated as MALDI matrices in the future. The CID-MS/MS analysis of curcumin analogues revealed a common fragmentation behavior of the tested compounds. It will be applied, in the future to determine metabolic by-products of the tested compounds as well as to develop targeted liquid chromatography (LC)-MS/MS methods.

Introduction: Intracytoplasmic sperm injection (ICSI) has been a successful assisted reproductive technique for men with severe male-factor infertility. However, ICSI requires the subjective selection of normal looking sperm, which does not preclude the transmission of genetically abnormal sperm. Correlation between abnormal sperm morphology and chromosomal abnormalities has been suggested but not been conclusive and less is known about the connection between sperm morphology and DNA integrity. Sperm morphology will be evaluated on its ability to identify the level of chromosomal abnormalities or fragmented DNA in sperm. To further focus this investigation on sperm morphology, men with infertility isolated to abnormal sperm morphology (isolated teratozoopsermia) are examined. Materials and Methods: Sperm from isolated teratozoopsermic men (n=10) were analysed by fluorescent in situ hybridization (FISH) and terminal dUTP nick-end labelling (TUNEL) assays to determine the level of aneuploidy and DNA fragmentation, respectively. These results were also compared to that of sperm from control men (n=9) of proven fertility and normal seminal parameters. Results: Sperm from teratozoospermic men, compared to control men, had higher rates of total chromosomal abnormality (5.90±3.74% vs. 2.35±0.87%, P=0.0128), total aneuploidy (4.90±2.82% vs. 1.99±0.65%, P=0.0087), and chromosome 13 disomy (0.77±0.50% vs. 0.20±0.14%, P=0.0046). In control samples, incidence of tapered heads associated with supernumerary chromosomal abnormalities (rs=0.9747, P=0.0167). In teratozoospermic samples, incidence of amorphous heads associated to chromosome 13 disomy and sex chromosome aneuploidy (rs=0.6391, P= 0.0466; rs=0.8049, P=0.0050, respectively). Tail abnormalities were associated with chromosomal abnormalities (bent tail-disomy 13: rs=0.7939, P=0.0061; 2-tailed-disomy 13: rs=0.8193, P=0.0037; 2-tailed-supernumerary chromosomal abnormalities: rs=0.7534, P=0.0119). Levels of DNA fragmented sperm were higher in teratozoospermic men than control men (60.28±21.40% vs. 32.40±17.20%, P=0.0121). DNA fragmentation in sperm positively correlated with the incidence of sperm with bent necks in control samples (rs=0.8571, P=0.0238) and round headed sperm in teratozoospermic samples (rs=0.6727, P=0.0390). Conclusions: Sperm of isolated teratozoospermic men have elevated rates of chromosomal abnormalities and DNA fragmentation compared to that of fertile controls. Specific abnormal sperm morphology can be correlated wiht chromosomal abnormalities and level of DNA fragmentation in sperm and this may prove useful in sperm selection for ICSI when applied to isolated teratozoospermic patients.

Historically, New Zealand was almost completely forested below the alpine treeline, but 1000 years of Polynesian and European colonisation has resulted in the destruction of nearly three-quarters of the original forest cover. I assessed historical patterns of deforestation and forest fragmentation in relation to all major topographical, climatic and anthropogenic variables that may drive forest loss. Much of the deforestation occurred in regions with drier climates, reflecting the fact that human population density has always been highest in areas with moderately dry climates and that dry forests burned much more readily and extensively. The large remaining tracts of forest are mainly restricted to high elevations, while the lowland forests have been fragmented into small, isolated remnants. Fragmentation of the surviving forests increases their susceptibility to edge effects and invasion by adventive species, indelibly altering the ecological communities they support. Although a large proportion of the remaining forest is owned or managed by the Department of Conservation, the distribution of that protection is greatly skewed towards areas of low economic value and is not representative of the relative conservation value of landscapes that differ in their environments and degree of forest cover. Forest cover in the majority of New Zealand landscapes has been reduced below the level of an expected extinction threshold of 30 % forest cover in the landscape, and ongoing deforestation threatens to force more landscapes below the critical threshold. Deforestation is still occurring across the country, and it is concerning that current deforestation rates in some areas are far greater than those observed in tropical, developing nations. I showed that the remaining forest fragments in New Zealand have complex, irregular shapes, and find ubiquitous evidence that core habitats within individual fragments are spatially discontinuous, comprising multiple, disjunct cores of small average area. Because population density of forest-interior species typically decreases with decreasing habitat area, multiple, disjunct cores support a lower total population size than a single, discrete core of the same total area. I found in a spatially explicit, landscape-level analysis of habitat fragmentation in New Zealand that simple core-area models consistently overestimate the carrying capacity of habitat fragments. Habitat fragmentation and habitat destruction are widely recognised as two of the leading threats to the continued maintenance of global biodiversity. The effects of habitat fragmentation on biodiversity fall into five categories that describe the spatial and landscape attributes of fragmented ecosystems; (1) fragment area, (2) edge effects, (3) fragment shape, (4) fragment isolation, and (5) matrix structure. Each attribute affects species individually according to their particular biological requirements and life history strategies, leading to complex, and often conflicting, sets of results in the empirical literature. Furthermore, it is now apparent that the effects of fragmentation can take many decades to become apparent and that the spatial arrangement of habitat fragments can interact with other ecological processes to magnify the detrimental impacts of fragmentation on species. I synthesised the published effects of habitat fragmentation on the morphology, distribution and abundance of invertebrate populations, species and communities, and present examples of time lags and synergies from the fragmentation literature. I explicitly considered the underlying mechanisms determining the responses ofindividuals to fragmentation and discussed the role of species traits in determining species vulnerability to changes in the spatial attributes of fragmented landscapes. I sampled 35,461 beetles from a fragmented forest and matrix system in New Zealand over very large gradients of fragment area (10-2 to 106 ha) and edge distances (up to 1,024 m from the forest edge into both the forest and the adjacent matrix interiors). The beetle fauna was very diverse, with 893 species identified in 65 families, representing nearly 20 % of the known species in New Zealand. Beetle communities were strongly structured by forest fragmentation, but in species-specific ways. Distance to edge was consistently shown to have the largest effect on community composition, but, surprisingly, an interaction between area and distance to edge had a stronger impact on community structure than fragment area alone. I developed a new method to partition the variance in community composition that was explained by putative area and edge effects. The method uses backwards stepwise regression to determine significant predictors of gradients in beetle species composition that were identified by canonical ordination. I found that edge effects were driven partially by small-scale alterations to microhabitat and microclimate and partially by changes in landscape composition that varied with distance to edge. In contrast, fragment area effects were driven primarily by edge effects, the strength of which varied significantly with fragment area. I took a novel approach to characterising the responses of 185 common species to habitat edges by modelling species abundances across edges with a general logistic model that described sigmoid trends in abundance for forest specialist and matrix specialist species, as well as unimodal trends in abundance for edge specialist species. I used the second derivatives of the logistic and unimodal models to statistically determine the width of species response zones to edge effects. Beetle species responses to forest edges occurred over far greater scales than previously suspected, with edge response zones for some species extending for more than 1 km. Average edge response zones were 194 m wide and, for many species, began in the forest but extended into the adjacent matrix. Species were categorised according to their responses to fragment area and distance to edge. Closely related species were expected to be placed in similar response categories because they are predicted to share suites of traits that determine their susceptibility or resilience to fragmentation by virtue of common ancestry. Despite many species exhibiting responses that could be grouped into categories, individual species responses to fragmentation were largely idiosyncratic with even closely related species exhibiting strongly contrasting responses to fragmentation.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S. in Physics)--United States Naval Postgraduate School, 1959. / "Physics and Mathematics" -t.p. Includes bibliographical references (p. 33).

Thesis (Ph.D.)--University of California, Berkeley, 1963. / "UC-4 Chemistry" -t.p. "TID-4500 (19th Ed.)" -t.p. Includes bibliographical references (p. 125-127).