Student Number : 0316118X - MPH research report - School of Public Health - Faculty of Health Sciences / Introduction: On the weekend of 16 – 17 December 1995, the community of Macassar was exposed to elevated levels of sulphur dioxide vapours (SO2) caused by a fire on a nearby stockpile for approximately 21.5 hours. It has been estimated that community members were exposed to levels as high as 200 parts per million (ppm) of this gas as some 15 000 tons of the sulphur stockpile ignited. This resulted in a toxic plume of SO2 being blown over the Macassar area by the prevailing wind. The aim of this study was to assess the environmental and host factors associated with persistent lower respiratory symptoms among residents of this community six years after being acutely exposed to elevated exposures of SO2 vapours. Materials and methods: A case-control study was conducted. The cases and controls were selected from adult residents who reported to the Macassar disaster project clinic for a health assessment in order to lodge a medico-legal claim. Survey instruments included a questionnaire, clinical examination and clinical record review by an expert panel. A case was defined as an adult resident who presented to the clinic for an examination with persistent (at year 1 and 6 after the disaster) lower respiratory symptoms. Controls were chosen from clinic attendees without lower respiratory symptoms at year 1 and 6. Environmental exposure was calculated by using the Industrial Source Complex Short Term Model (ISCST 3) to predict time-averaged concentrations at specified receptor locations. Multiple logistic regression was used to investigate the association between lower persistent respiratory symptoms, host and environmental factors (estimated concentration and duration of exposure to SO2). Results: A total of 76 cases and 180 controls were selected. The cases and controls were comparable with respect to age, gender, height and smoking status. The results indicated that a medical history of pulmonary tuberculosis at least one year prior to the fire (OR: 3.5, CI: 1.5-8.4) was significantly associated with having persistent lower respiratory symptoms. Furthermore, subjects with persistent lower respiratory symptoms were nine times more likely to report symptoms of tight chest (OR: 9.9; CI: 5.2-19.1), and twice as likely to report shortness of breath (OR: 2.0; CI: 1.0-4.1) at the time of the fire. None of the exposure metrics (total hours of exposure, cumulative exposure, peak exposure) were significantly associated with persistent lower respiratory symptoms. However, peak SO2 exposure estimated at hour 15 was significantly associated with persistent lower respiratory symptoms (OR: 1.0; CI: 1.0-1.1). Discussion: The results of this study are consistent with previous studies reporting lower respiratory tract symptoms after chemical exposure irrespective of age or smoking status. Furthermore, as in other studies respiratory health status was a significant factor in determining susceptibility to SO2 exposure. Various reports in the literature suggest that exposure > 20 ppm is associated with chronic respiratory symptoms. This however was not demonstrated in this study, using estimates of exposure calculated using the ISCST model suggesting possible exposure misclassification. “Self-selection” bias was an important limitation in this study, since the entire study population was self-referred and as such the study population was not randomly selected. Another limitation is the possibility that there may be potential recall bias operating since the fire incident happened six years ago; however this was considered unlikely as there was nondifferential reporting between cases and control. Self reported symptoms on the questionnaires might have been over-reported due to fear, anxiety and stress or secondary gain related to compensation issues. The lack of association between exposure variables and persistent asthma may have also been due to lack of power (small sample size), although this was thought to be a minor contributory factor. Conclusion: Host-related factors such as a previous history of pulmonary TB and acute asthma-like symptoms at the time of the fire were important predictors of persistent lower respiratory symptoms reported by residents 6 years after acute exposure to SO2 vapours emanating from a sulphur fire.

This thesis describes the development of new thermal and oxidative radical cyclization methodologies and their application to the total syntheses of alkaloids, particularly to bridged diketopiperazine (DKP) alkaloids. A practical solvent free approach to diverse DKPs and quinazolines is described. The methodology proceeds by thermal silica gel mediated deprotection of the Boc protecting group and intramolecular condensation of the resulting free dipeptides and tripeptides. It was applied to the total syntheses of alkaloids glyantrypine and ardeemin. A major part of the thesis concerns with the discovery and applications of novel diketopiperazine derived alkoxyamines. Their propensity to undergo facile thermal C-O bond homolysis to generate captodative DKP radicals and persistent TEMPO radical allowed using them as radical surrogates. The methodology takes advantage of the persistent radical effect (PRE). The methodology based on PRE was applied in an asymmetric approach to the alkaloid asperparaline C. An asymmetric synthesis of a very advanced precursor to asperparaline C, 8- oxoasperparaline C, was accomplished in 11 steps and 15% overall yield. The key steps of the synthesis include a direct oxidative cyclization of DKPs, regioselective furan dearomatization with singlet oxygen and a reductive...

Extreme flooding of rivers may contribute to increased loading of persistent organic pollutants (POPs) to the Great Lakes, the Mississippi river, and other large lakes and surface waters downstream of industrial and urban areas. This study examines the fate of POPs that were mobilized during heavy flooding of the Cedar River and the small urban city of Cedar Rapids, Iowa during the summer of 2008. This study focuses polychlorinated biphenyls (PCBs). We hypothesize that these PCBs were mobilized by the flood water and that residues remained in the soils and sediments of the residential areas of the city. To test our hypothesis, soil samples were collected from ~200 of residential locations in the downtown Cedar Rapids area and analyzed for the three compound groups. Samples were extracted using an accelerated solvent extraction (ASE 300), and analyzed using GC/ECD, GC/MSD and GC/MS/MS.

This thesis was concerned with investigating a visual-illusionary phenomenon that co-occurs with post-traumatic anxiety symptoms. More specifically, individuals who report recurring specific memories of a fearful event (RSM) also tend to report a persistent illusion of movement (PIM) upon prolonged visual fixation (Tym, Dyck & McGrath, 2000). The development of a visual test (i-Test) designed to reliably elicit PIM has enabled research to be conducted on the nature and correlates of this type of visual disturbance. The present research aimed: 1) To develop a standard protocol for assessment of PIM and RSM; 2) to test the reliability of the i-Test in eliciting PIM in a student sample 3) to test the predictive relationship between dissociation and anxiety symptoms with PIM and RSM 4) to formulate and test a hypothesis regarding a mechanism underlying PIM. The first study screened 142 participants for RSM and PIM using self-administered questionnaires designed by Tym (personal communication, 2001). There was an unexpectedly high rate (54.2%) of PIM and RSM (37.3%) in the sample, which appeared to be the product of questionnaire design limitations. Two semi-structured interviews were developed and subsequently tested on a new sample of 50 participants in Study 2. Study 2 documented intra-rater and inter-rater reliability co-efficient of sufficient strength to indicate good reliability for the semi-structured interviews. The results of Study 2 indicate that PIM is a relatively stable symptom over a 30-minute and one-week test-retest time frame. / The onset time for PIM was relatively consistent between participants, with a mean latency of approximately 7 seconds. The oscillation rate of PIM was relatively consistent between individuals, with a mean average oscillation of approximately 0.8Hz. The third study tested a sample of 148 participants using the revised assessment protocols. The base rate for PIM (16.2%) and RSM (18.9%), and the concordance rates (46% to 54%) were slightly stronger than the Tym et al. (2000) community based study (33%). In addition to this, 11 other illusionary phenomena were documented, however none of these visual symptoms significantly correlated with RSM. The average oscillation rate is comparable to the rate documented in Study 2, further establishing the consistency of the reported rate of PIM oscillations between individuals. In Study 3, each participant was assessed for levels of dissociation (Dissociative Experiences Scale), somatic arousal (Mood and Anxiety Symptoms Questionnaire – Anxious Arousal Scale) and anxiety sensitivity (Anxiety Sensitivity Index). The results indicate that gender and dissociation significantly predict RSM status, and self-reported levels of anxious-arousal significantly predict PIM status. A multiway frequency analysis between the sub-components of RSM and PIM revealed that the physiological arousal inducing properties of the recurring memory is the only significant predictor of PIM. / The observed relationship between RSM and PIM may reflect the broader relationship between anxiety and dissociation. A pulsatile hypothesis was proposed as a feasible mechanism underlying PIM, due to the rhythmical nature of the visual disturbance, the range of the documented oscillations, and its specificity to psychological disorders characterised by cardiovascular sensitivities. All participants were administered the i-Test prior to and following aerobic exercise aimed at increasing pulse rate to 80% of maximum load. An increase in physical exertion significantly increased the latency of PIM onset, but did not impact on the rate of PIM. PIM rate appeared relatively consistent between individuals at 0.6Hz to 0.8Hz at the pre-exercise condition. Several participants who reported PIM also displayed obvious nystagmoid-like movements during the i-Test perceptual task. The role of eye-movements in PIM requires further investigation by future ophthalmological research. The final aim of Study 3 was to investigate the relationship between RSM/PIM and flicker sensitivity. Through the use of a Critical Flicker Frequency/Fusion task (CFF), each participant’s sensitivity to flicker was determined. In addition to detecting sensitivity thresholds, CFF is also considered to be a reliable indicator of the level of cortical arousal. / The results of this study suggest that individuals with RSM have a higher sensitivity to flicker than other participants, however there was a non-significant relationship between CFF and PIM. The lack of relationship between PIM and CFF may be due to issues concerning statistical power and effect-size. Future research is required to investigate this link in more detail. The overall results of this thesis suggest that i-Test elicited PIM is a reliable phenomenon that is associated with higher rates of traumatic memories when compared with persons who do not report this visual symptom. The strength of the association between RSM and PIM, however, does not support the use of the i-Test as a marker for the presence of RSM outside a clinical sample. The reliability of PIM as a phenomenon and its association with anxiety symptoms may be of theoretical importance in enabling future research to investigate the relationship between visual symptoms and anxiety-related pathology.

DDT, an extremely widely used organochlorine pesticide, was banned in most developed countries more than 30 years ago. However, DDT residues, including 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE), still persist in the environment and have been identified as priority pollutants due to their toxicity and their ability to bioaccumulate and biomagnify in the food chain. In particular, DDE was long believed to be &quotenon-biodegradable&quote, however some microorganisms have now been isolated that are able to metabolise DDE in pure culture. Terrabacter sp. strain DDE-1 was enriched from a DDT-contaminated agricultural soil from the Canterbury plains and is able to metabolise DDE to 4-chlorobenzoic acid when induced with biphenyl. The primary objective of this study was to identify the gene(s) responsible for Terrabacter sp. strain DDE-1�s ability to metabolise DDE and, in particular, to investigate the hypothesis that DDE-1 degrades DDE cometabolically via a biphenyl degradation pathway. Catabolism of biphenyl by strain DDE-1 was demonstrated, and a biphenyl degradation (bph) gene cluster containing bphDA1A2A3A4BCST genes was identified. The bphDA1A2A3A4BC genes are predicted to encode a biphenyl degradation upper pathway for the degradation of biphenyl to benzoate and cis-2-hydroxypenta-2,4-dienoate and the bphST genes are predicted to encode a two-component signal transduction system involved in regulation of biphenyl catabolism. The bph gene cluster was found to be located on a linear plasmid, designated pBPH1. A plasmid-cured strain (MJ-2) was unable to catabolise both biphenyl and DDE, supporting the hypothesis that strain DDE-1 degrades DDE cometabolically via the biphenyl degradation pathway. Furthermore, preliminary evidence from DDE overlayer agar plate assays suggested that Pseudomonas aeruginosa carrying the strain DDE-1 bphA1A2A3A4BC genes is able to catabolise DDE when grown in the presence of biphenyl. A second objective of this study was to characterise pBPH1. The complete 84,054-bp sequence of the plasmid was determined. Annotation of the DNA sequence data revealed seventy-six ORFs predicted to encode proteins, four pseudogenes, and ten gene fragments. Putative functions were assigned to forty-two of the ORF and pseudogenes. Besides biphenyl catabolism, the major functional classes of the predicted proteins were transposition, regulation, heavy metal transport/resistance, and plasmid maintenance and replication. It was shown that pBPH1 has the terminal structural features of an actinomycete invertron, including terminal proteins and terminal inverted repeats (TIRs). This is the first report detailing the nucleotide sequence and characterisation of a (linear) plasmid from the genus Terrabacter.

An extensive use of chemicals in countless consumer products has resulted in human exposure to several persistent organic pollutants (POPs). Sufficient knowledge about their chemical composition properties and environmental faith is required, to be able to proper risk assess and regulate the substances. Significant data gaps exist regarding knowledge of actual exposure to humans and toxicological effect data. The objective of this thesis was to add human exposure data of a few POPs from four case studies. The analytes discussed in this thesis are polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD). Three European populations were studied. Milk was analysed from a group of women, who were accidentally exposed to high levels of 2,3,7,8-TetraCDD (TCDD) in Seveso, 1976. Still today, twice as high TCDD levels were recorded in the milk, compared to background concentrations. Serum was analysed from mothers and their infants from The Netherlands. Cord serum contained equal amounts of POPs as in mother’s blood, indicating non-hindered placenta transfer. Serum analysed from Swedish men and women with a high fish intake had elevated PCB and PCB metabolite (OH-PCB) levels. Additionally, butter was collected worldwide and shown to be a suitable matrix for dairy product survey of POPs. The exposure levels in the four papers were compared to recently reported exposure levels in Europe. It is indicated in the thesis that the PCDDs/PCDFs and PCBs toxic equivalency (TEQ) levels are of concern, i.e. the ratio between threshold levels for adverse health effects and TEQ exposure levels is lower than requested margin of safety. Average levels of PBDE/HBCDD in the European population are estimated to be of no concern today, but for individuals with intakes at the 95th percentile are the current margins of safety small.

The remote sub-Arctic/Arctic environment has due to human activities become a sink for organohalogen contaminants (OHCs). These OHC include traditional contaminants such as polychlorinated biphenyls (PCBs), DDTs and technical mixtures of polybrominated diphenyl ethers (PBDEs), all included in the Stockholm Convention list of persistent organic pollutants (POPs). Other OHCs, currently under evaluation to be included among the POPs i.e. short chain chlorinated paraffins (SCCPs) and hexabromocyclododecane (HBCDD) are also found in these environments as well as a whole range of other OHCs. The main objective of this thesis is to increase the knowledge about the presence of OHCs in a high trophic Arctic shark species, the Greenland shark (Somniosus microcephalus). The Greenland shark is an opportunistic feeder, occasionally feeding at the top of the Arctic marine food chain. Furthermore may this species have a life span in excess of 100 years and is probably among the oldest of any fish species. These traits make the shark prone to accumulate elevated concentrations of OHCs. This has shown to be true for the Greenland sharks studied and most of the targeted OHCs were determined in the species. The highest concentrations were observed for the DDTs, ranging up to 26 μg/g fat. Other OHCs reported that are of special interest are SCCPs and brominated flame retardants used as replacement products to PBDEs; pentabromoethylbenzene (PBEB) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). Also a range of OHCs whose origin is assumed to be natural, were shown to be present in Greenland sharks. This thesis is stressing the fact that even though the use of certain OHCs has been banned for decades they are still present at high concentrations in the deep waters of the Arctic. Therefore it is of major importance to continue to monitor the fate of traditional and emerging OHCs in the environment, and for this purpose the Greenland shark is an excellent species. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

<p>The work presented in this dissertation includes the study of cohomology and cohomological operations within the framework of Persistence. Although Persistence was originally defined for homology, recent research has developed persistent approaches to other algebraic topology invariants. The work in this document extends the field of persistence to include cohomology classes, cohomology operations and characteristic classes. </p><p>By starting with presenting a combinatorial formula to compute the Stiefel-Whitney homology class, we set up the groundwork for Persistent Characteristic Classes. To discuss persistence for the more general cohomology classes, we construct an algorithm that allows us to find the Poincar'{e} Dual to a homology class. Then, we develop two algorithms that compute persistent cohomology, the general case and one for a specific cohomology class. We follow this with defining and composing an algorithm for extended persistent cohomology. </p><p>In addition, we construct an algorithm for determining when a cohomology class is decomposible and compose it in the context of persistence. Lastly, we provide a proof for a concise formula for the first Steenrod Square of a given cohomology class and then develop an algorithm to determine when a cohomology class is a Steenrod Square of a lower dimensional cohomology class.</p> / Dissertation

Synthesis of heat shock proteins (Hsps) in response to elevated temperatures and other denaturing agents (including UV, heavy metals, and energy depletion) is a common productive response of prokaryotic and eukaryotic cells. Therefore, increasing in production of heat shock protein has been considered a sign of cells under stress. The phylum Sipuncula comprises of about 300 species worldwide; they are bilaterally symmetrical, unsegmented, and deposit feeding marine worms common in the substrate of wetland. In this research, I studied the dominant species Sipunculus nudus and analyzed it proteomics to reveal how it responses to persistent organic pollution. In order to compare the difference between HSP70 and HSP90, Sipunculans were sampling from two wetland (Xiangshan and Wanggong) in Hsinchu and Changhua,, respectively. The results showed that the concentrations of PAHs and OCPs both in substrate and S. nudus tissues from Xiangshan were higher than Wanggong. The concentrations of PAHs and OCPs in both areas showed that the environmental- sediment levels were higher than the sediment inside the gut or the body tissues. Principal component analysis showed that the compositions in S. nudus from both area were similar; however PAHs compositions from the environmental sediment or the sediment of the gut were similar. When the concentrations of HSP70 and HSP90 between both areas were compared, HSP70 expressions did not significant differed in both areas, while HSP90 express was higher in the S. nudus from Xiangshan than Wanggong. For S. nudus Hsp90 was upregulated in highly polluted area (i.e. Xiangshan). I propose that tissue expression of HSP90 plays an important role in the survival of S. nudus, and detection of HSP90 may provide pollution information of the surrounding environment.

Polybrominated diphenyl ethers (PBDEs) are anthropogenic chemicals whose environmental behavior is similar to the well-known polychlorinated biphenyls (PCBs). Few studies have quantified the amount and distribution of PBDEs in the southern hemisphere and Antarctica. The analyses reported in this dissertation document the levels of PBDEs in lichens, mosses and seabird eggs collected at King George Island, Antarctic Peninsula. The analyses were carried out using Gas Chromatography/Electron Impact-Mass Spectrometry (GC/EI-MS). Employing the ion stacking technique lowered detection limits and ensured instrument selectivity and sensitivity to the compounds of interest. Lichens and mosses absorb PBDEs directly from the atmosphere and their contamination indicates that long-range transport is the primary source of these chemicals to King George Island. The congener patterns of PBDEs in plants indicate that commercial mixtures of Penta-BDE and Octa-BDE have reached Antarctica. Differences in the levels of PBDEs observed in lichens and mosses are probably due to factors that govern the uptake of PBDEs from the atmosphere. Contamination in lichens showed a positive correlation with local precipitation. Conversely, absorption of PBDEs in mosses appears to be controlled by other plant-specific factors. Marine phytoplankton-derived aerosols are hypothesized to play an important role in the atmospheric transport of PBDEs to the Antarctic environment. PBDEs in south polar skua eggs revealed much higher concentration than in penguin eggs. This is likely associated with the northward migration of these seabirds during the non-breeding season. While penguins reside year-round in Antarctica, south polar skuas migrate northward and can be seen in boreal oceans during the austral winter. Distribution of PBDEs in penguin eggs matches the pattern found in local vegetation suggesting a common source for the chemicals. In contrast, the congener pattern of south polar skuas suggests that birds breeding at King George Island are wintering in the northwestern Pacific Ocean. A potential metabolism of PBDEs in penguin eggs during the incubation period seems to be limited. Most congeners were unaltered from source material in the eggs of chinstrap and gentoo penguins. Low levels of PBDEs, short incubation periods and energy constraints may explain these observations.