No description available.

Estimation of the transport of persistent organic pollutants via air-water exchange requires precise field concentrations from advanced experimental techniques and adequate physic-chemical parameters generated from proper methods. In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in the ambient air and water column of Kaohsiung Harbor lagoon were measured and used to determine the air-water exchange fluxes of these compounds from December, 2003 to January, 2005. The Whitman¡¦s thin-film model was used by taking temperature and salinity corrected Henry¡¦s law constants into the model to calculate the fluxes. In addition, particulate concentrations and composition in the ambient air and water column were used to apportion PAH sources and dry particle deposition of PAHs, PCBs and HCB. Instantaneous air-water exchange fluxes of PAHs, PCBs and HCB were calculated from twenty-two pairs of air and water samples. The highest net volatile (+3560 ng m-2 day-1) and absorptive (-1230 ng m-2 day-1) PAH fluxes in this study were both obtained from the three-ring PAH, phenanthrene on April 7 and January 27 in 2004, respectively. Differences of flux magnitude and direction between dry and rain season were obvious for PAHs in this study. Most net fluxes of PCB homologues and HCB in this study are from water to air (net volatilization). The highest net volatile flux observed was +172 ng m-2 day-1 (dichlorobiphenyl) in December, 2003 due to elevated wind speed and dissolved concentration, while the only net absorptive flux observed in this study was -0.03 ng m-2 day-1 (dichlorobiphenyl) in January, 2004. Mean daily PAH diffusive fluxes were -727 ng m-2 day-1 influx in dry season but +808 ng m-2 day -1 efflux in rain season and integrated 3.6 kg and 4.0 kg of PAHs were absorbed into and emitted from harbor lagoon surface waters in dry and rain seasons, respectively. The net PCBs and HCB fluxes suggest that the annual sum of 69 PCBs and HCB measured in this study were mainly volatile (57.4 and 28.3 ¡Ñ103 ng m-2 yr-1, respectively) and integrated 1.5 kg and 0.76 kg of PCBs and HCB emitted from harbor lagoon surface waters to ambient atmosphere in the year. Sources apportionment by the isomer ratios, PAHs in the air phase were mainly from grass, wood and coal combustion and some from liquid fuel combustion. Unlike that in air phase, fluoranthene / fluoranthene + pyrene ratios of water phase suggest PAHs were from incomplete-combusted fuel particles emitted from vehicle exhaust. Principal component analysis (PCA) extracted three meaningful PCs for air and water samples, respectively. For the air samples, the three major sources suggested by three sources are vehicular emissions, volatilization to the air from contaminated soil or waters and the coal-burning emission. Among the water samples, the three major sources suggested by three sources are vehicular emissions, oil spill source and coal-burning emission. Air particulate concentrations of PAHs, PCBs and HCB were also used to calculate their dry particle deposition. Throughout our sampling campaigns, PAH dry particle fluxes were quite comparable to fluxes of air-water exchange. On the contrary, PCB and HCB dry particle deposition flux were negligible comparing to their air-water exchange fluxes. Our results suggest PAHs exhibits strong absorptive or weaker volatile fluxes in the dry season but the opposite in the rain season. However, for PCBs and HCB, Kaohsiung Harbor water is potentially an important source to ambient air.

Persistent organic pollutants (POPs) were widely distributed in the environment, and may cause hazardous effects to human health. Among these pollutants, polychlorinated biphenyls (PCBs), due to their toxicity and bioaccumulation, have been banned in the mid 1970s in most countries. They are ubiquitous and highly persistent, and therefore, PCBs are of most concern for their potential to be globally transported through air-water exchange. Previous studies such as Fang et al.¡]2008¡^ and Chen¡]2010¡^have studied the air-water exchange of PCBs in Kaohsuing Harbor. This study not only continued monitoring this area but also included Gao-Ping coastal areas and Lanyu Island in order to determine the air-water exchange fluxes of PCBs in harbor and coastal area. The aim of this study was to determine the magnitude of PCB air-water exchange fluxes and dry deposition fluxes by measuring the gas/particle phase concentrations in ambient air and dissolved/particle phase concentrations in water column, and to analyze the compositional patterns of PCB homologs. Hierarchical cluster analysis (HCA) and principal components analysis (PCA) were performed with compositional patterns of commercial products such as Aroclor mixtures to gain a better understanding of pollution topography for PCBs . The concentrations of £UPCBs in the ambient air ranged from 116 to 439 pg m-3, with an average concentration of 164 pg m-3 . The average PCB concentrations in gas and particle phase were 161 pg m-3 and 2.91 pg m-3, respectively. The concentrations of £UPCBs in water column ranged from 14.1 to 1750 pg L-1, with an average concentration of 233 pg L-1. The average PCB concentrations in dissolved and particle phase were 162 pg L-1 and 70.4 pg L-1, respectively. The highest gaseous concentration of £UPCBs was observed in GRE in November, suggesting that wind direction and Linyuan Industrial Park may be the major contributor of PCBs there. However, the highest dissolved concentration of £UPCBs was found in KHH in August, indicating that rainfall and runoff of Typhoon Morakot were evident in source. Results from HCA, PCA and compositional patterns indicate that lower chlorinated congeners (dichlorobiphenyls to tetrachlorobiphenyls) were predominant in the gas and dissolved phase of ambient air and water column. In particle phase of ambient air and water column, PCB compositions were dominated by higher chlorinated congeners (tetrachlorobiphenyls to hexachlorobiphenyls). TEQ was used to determine the level of pollution for environment and human health. The average TEQ was 0.0008 pg-TEQ m-3 in gas-phase of ambient air and was 0.0006 pg-TEQ L-1 in dissolved phase in water. PCB114 was observed to be the predominant congener in this study. The average flux of air-water exchange was ¡Ï31.5 ng m-2 day-1, and was much higher than the average flux of dry deposition (¡Ð0.54 ng m-2 day-1). The net PCB fluxes in KHH suggest that annual air-water exchange was ¡Ï40.2 mg m-2 yr-1 and estimated yearly, 0.5 kg of PCBs were emitted from water column of Kaohsiung harbor to the ambient atmosphere.

Before January 2003, the Dapeng Bay lagoon was occupied by oyster culture racks and fish farming cages. Along with the development of the Dapeng Bay National Scenic Area Administration, the government has started taking actions on removing oyster culture racks, and has kept improving the quality of lagoon water. Nowadays, the government is implementing sediment dredging plan. As to discuss the change of biogeochemical processes, this study is divided by three parts, including the first stage, before the removal of oyster culture rafts; second stage, after the removal of oyster culture rafts, and the third stage, after implementation of sediment dredging. At the first stage, the annual mean of water exchange time at the Dapeng Bay was approximately 10 days. At the second and third stage, the annual mean of water exchange time were 6.2 days and 8.3 days, respectively. The difference is not significant between the second stage and third stage. The trend of water exchange time is similar to the seawater exchange rate. Distributions of chlorophyll a were controlled by temperature and solar radiation, rather than by nutrient concentration throughout three-stage periods. Although the change tendency between chlorophyll a, DIN, and DIP at the third stage is similar, chlorophyll a correlated positively with DIN and DIP only in fall. The net ecosystem production (NEP) was positive (p¡Ðr > 0) at all three stages, so the Dapeng Bay was always an autotrophic system throughout the study period. Before the removal of the oyster culture racks, the NEP was 5.64 mole C m-2 yr-1, after that, it increase to 11.64 mole C m-2 yr-1. During the sediment dredging period, the NEP was 14.31 mole C m-2 yr-1. The NEP increases 106 % from the first stage to the second stage, and increases 23% from the second stage to the third stage. The environmental remediation appears to produce significant influence on NEP. The concentration of DIN¡BDSi¡BDIP decreases by removing the oyster culture of racks. But the concentrations of particulate and dissolved organic carbon and nitrogen increase sharply after removing the oyster culture racks. Nevertheless, the concentration of dissolved organic carbon, nitrogen and the phosphorus decreases during the third stage, resulted mainly from the improvement of water quality. The system changed from the condition of phosphorus surplus (Si/N=1.8¡Ó1.2 and N/P=7.4¡Ó5.2) during the first and second stage to the condition of phosphorus limitation (Si/N=1.0¡Ó1.2 and N/P=22.2¡Ó18.7) during the third stage. The ratios of particulate organic carbon and nitrogen (POC/PN) are 7.7¡Ó1.1, 8.0¡Ó1.0, 6.5¡Ó1.3, respectively. The ratio at the third stage is very close to the Redfield ratio (C/N=6.6), which may result from the improvement of water quality. In terms of temporal and spatial variation of various parameters, DO variability was strong in the time scale than in the spatial scale, but nutrients and POC show a decrease of spatial variability from the first stage to the third stage. The removal of oyster culture racks, and the implementation of sediment dredging plan at the Dapeng Bay have significant influence on the improvement of lagoon environment for the past ten years.

The exchange of water mass into and out of Dongsha Atoll is analyzed based on field measurements, in the region of 116.7-116.92E 20.58-20.78N during year 2008-2010. Measured parameters include sea level, currents, waves, water temperature and bottom depth. The results show that (1) tidal current is the major driven force of water exchange in the Dongsha Atoll. (2) The major water pathway is the two channels at the northwest and southwest by the side of the Dongsha island. The north channel is more important than the south. (3) The volumn transport of wave contribution is small. (4) The estimated residual time of water in the atoll is about 2 days.

No description available.

Recent regulation mandates that ships conduct mid ocean ballast water exchange (BWE) prior to discharging foreign ballast in territorial waters of Australia, the U.S. and elsewhere. The enforcement of ballast water exchange legislation is undermined, however, by a lack of sensitive and reliable methods for verifying compliance. One way to assess compliance is to compare the concentrations of chemical tracers in ballast tanks with their known distributions in the open ocean. In this work, dissolved organic matter and trace elements are investigated as potential tracers of mid-ocean ballast water exchange on commercial voyages in the North Pacific and Atlantic Oceans. The optical properties of chromophoric dissolved organic matter (CDOM) are frequently used as tracers of water masses in bays and estuaries. Characterization of the underlying fluorescence spectra in seawater dissolved organic matter was performed using parallel factor analysis, allowing the identification of at least nine independently varying fluorescent components present in varying concentrations in the ocean and in ballast water. Two of the humic components were terrestrial in origin and their signals could be traced in the open ocean (Pacific and Atlantic) at levels of approximately 1.5% of riverine concentrations. One humic terrestrial component was sufficient for predicting the coastal vs. oceanic source of most ballast water samples, suggesting that single and dual channel fluorometers could be optimized for verifying ballast water exchange. Barium, manganese and phosphorus were also investigated as potential tracers. Measurements of Ba and P obtained via engine-cooling pipes on commercial vessels were consistent with previous oceanographic measurements. While Ba behaved conservatively in ballast water, concentrations of phosphorus fluctuated and Mn was removed in ballast tanks over time. Ba and P demonstrated considerable promise as ballast water tracers, exhibiting predictable concentrations in exchanged ballast tanks, given a priori knowledge of the ocean (Atlantic versus Pacific) in which BWE was performed.

<p>Ny kunnskap om billeddannelse av hjertet ved magnetisk resonans (MR) fremkommer i sivilingeniør Wibeke Nordhøys doktoravhandling ved Norges teknisk-naturvitenskapelige universitet (NTNU). Denne kunnskapen vil ha stor betydning for hvordan man kan finne fram til noninvasive undersøkelser, dvs. uten fysiske inngrep, av hjertemuskelens levedyktighet hos pasienter med tilstopninger i kransarterier (iskemisk hjertesykdom). </p><p>Mangan som kontrastmiddel og markør for levedyktighet (viabilitet) </p><p>Arbeidet har gitt ny kunnskap om mangan som intracellulær kontrastgiver og om vannutveksling i hjertemuskelen. Manganforbindelser har et stort potensial som kontrastmidler for MR av hjertet. </p><p>I dyreforsøk har Nordhøy vist hvordan det magnetiske sporstoffet mangan tas opp i hjerteceller via fysiologiske ionekanaler, og hvordan det øker kontrasten i MR-bilder ved å «lyse opp hjertecellene innenfra». Hun har også gitt viktige bidrag til forståelsen av hvordan man med MR kan skille mellom vann inne i og utenfor hjertecellene. I sum betyr dette at man har kommet et skritt videre mot at MR av hjertet vil gi gradert informasjon om nettopp hjertecellenes tilstand. Avhandlingen representerer derfor et viktig norsk bidrag til den internasjonale forskning innen molekylær billeddannelse. </p><p>Avhandlingen </p><p>Avhandlingen har tittelen «Manganese and the heart: Intracellular MR relaxation and water exchange across the cardiac cell membrane / Mangan og hjertet: Intracellulær MR relaksasjon og vannutveksling over cellemembranen i hjertet.» Avhandlingen er blitt til innenfor et tverrfaglig samarbeid mellom biofysiker, fysiologer og kjemikere med professor Per Jynge, Institutt for sirkulasjon og bildediagnostikk, NTNU, som hovedveileder og professor Jostein Krane, Kjemisk institutt, NTNU, som medveileder. Arbeidet har vært initiert via Norges forskningsråds strategiske universitetsprogram for medisinsk teknologi (SUP-I) i Trondheim. Det er finansiert av Norges forskningsråd, Det medisinske fakultet (NTNU) og Amersham Health. </p>

Ny kunnskap om billeddannelse av hjertet ved magnetisk resonans (MR) fremkommer i sivilingeniør Wibeke Nordhøys doktoravhandling ved Norges teknisk-naturvitenskapelige universitet (NTNU). Denne kunnskapen vil ha stor betydning for hvordan man kan finne fram til noninvasive undersøkelser, dvs. uten fysiske inngrep, av hjertemuskelens levedyktighet hos pasienter med tilstopninger i kransarterier (iskemisk hjertesykdom). Mangan som kontrastmiddel og markør for levedyktighet (viabilitet) Arbeidet har gitt ny kunnskap om mangan som intracellulær kontrastgiver og om vannutveksling i hjertemuskelen. Manganforbindelser har et stort potensial som kontrastmidler for MR av hjertet. I dyreforsøk har Nordhøy vist hvordan det magnetiske sporstoffet mangan tas opp i hjerteceller via fysiologiske ionekanaler, og hvordan det øker kontrasten i MR-bilder ved å «lyse opp hjertecellene innenfra». Hun har også gitt viktige bidrag til forståelsen av hvordan man med MR kan skille mellom vann inne i og utenfor hjertecellene. I sum betyr dette at man har kommet et skritt videre mot at MR av hjertet vil gi gradert informasjon om nettopp hjertecellenes tilstand. Avhandlingen representerer derfor et viktig norsk bidrag til den internasjonale forskning innen molekylær billeddannelse. Avhandlingen Avhandlingen har tittelen «Manganese and the heart: Intracellular MR relaxation and water exchange across the cardiac cell membrane / Mangan og hjertet: Intracellulær MR relaksasjon og vannutveksling over cellemembranen i hjertet.» Avhandlingen er blitt til innenfor et tverrfaglig samarbeid mellom biofysiker, fysiologer og kjemikere med professor Per Jynge, Institutt for sirkulasjon og bildediagnostikk, NTNU, som hovedveileder og professor Jostein Krane, Kjemisk institutt, NTNU, som medveileder. Arbeidet har vært initiert via Norges forskningsråds strategiske universitetsprogram for medisinsk teknologi (SUP-I) i Trondheim. Det er finansiert av Norges forskningsråd, Det medisinske fakultet (NTNU) og Amersham Health.

Imaging techniques provide a method for non-invasive longitudinal monitoring of cancer therapies, but common metrics such as tumour size are late markers and do not indicate heterogeneity of response. Apoptotic cell death is an earlier marker of tumour response and produces molecular and cellular-level changes (macromolecular breakdown, membrane changes and cell shrinkage) that may be detectable by magnetic resonance imaging (MRI). Previous studies using conventional MRI methods have shown little sensitivity to apoptosis. In this thesis it is hypothesized that, using an extracellular contrast agent to affect the MRI property of relaxation for extracellular water preferentially, parameters related to water in the intracellular and extracellular environments and the exchange between them can be obtained and will be sensitive to apoptosis. It is also hypothesized that membrane changes and macromolecular breakdown are detectable by the technique of magnetization transfer. Measurements of relaxation in the presence of contrast agent in vitro demonstrated a decrease in extracellular water fraction and an increase in the rate of water exchange across the plasma membrane during apoptosis. In vivo, this method was complicated by the difficulty of delivering contrast agent to the tumour, but regions with good delivery showed correlation between high water exchange rates from MRI and apoptosis in histology. Magnetization transfer studies indicated only small changes in vitro during apoptosis and these were largely related to changes in the free water, so this method was not investigated further. Further work is required to determine the tumour lines where the water exchange methods may be applied reliably. Nevertheless, the method of measuring water exchange presented in this thesis can be performed in a clinically-feasible amount of time (~20 minutes). It therefore has potential in detecting apoptosis and predicting therapy response. It also emphasizes the role of water exchange in conventional MRI relaxation experiments.