Phytoremediation strategies for recalcitrant chlorinated organics

Thesis (Ph.D.) University of Alaska Fairbanks, 2000The purpose of the research was to investigate novel strategies for the phytoremediation of recalcitrant chlorinated organic soil contaminants. The recalcitrance of many chlorinated organics is related to chemical stability and bioavailability. Mycorrhizal fungi have the potential to enhance the degradation of such compounds through the action of lignolytic enzyme systems, and to increase the bioavailability of such compounds through increased root surface area and reach. Furthermore, the addition of surfactants has the potential to increase compound bioavailability via increased solubility. The organochlorine pesticide aldrin, and the polychlorinated biphenyl 3,3'4,4 '-tetrachlorobiphenyl (TCB) were chosen as representative recalcitrant contaminants. Feltleaf willow (Salix alaxensis) and balsain poplar (Populus balsamifera) were chosen as vegetative species likely to be useful for phytoremediation in sub-arctic ecosystems. Mixed-culture mycorrhizal fungi were first shown to be capable of taking up the hydrophobic contaminants in vitro. In the same experiments, surfactant addition increased the level of contaminant uptake. In subsequent vegetative uptake studies, mycorrhizal infection was highly correlated with the uptake of aldrin and TCB in the willow systems. In the poplar systems, this correlation was not as strong. Once taken up into the vegetative matrix of either species, most of the carbon originating from the chlorinated compounds existed as bound transformation products. Additionally, water-soluble transformation products of aldrin were formed in all of the soils tested, and such transformations were enhanced in the presence of vegetation. TCB transformation products were not detected in any of the soils tested. Surfactant addition did not impact the fate of either contaminant in the vegetative uptake studies. The surfactants, in the concentrations added, did not sufficiently solubilize the contaminants into the soil solution. The results of these studies indicated that the phytoremediation of recalcitrant chlorinated organics such as aldrin and TCB could be enhanced through the action of mycorrhizal fungi, and that surfactant addition has the potential to increase mycorrhizal uptake. Field studies were recommended, involving the use of specific degradative fungal species and effective surfactants

Taurine

This thesis is a primary investigation into a new synthesis of taurine. The sulfite of ethylene glycol is reacted with ammonium hydroxide to produce taurine

Geophysical Applications for Arctic/Subarctic Transportation Planning

This report describes a series of geophysical surveys conducted in conjunction with geotechnical investigations carried out by the Alaska Department of Transportation and Public Facilities. The purpose of the study was to evaluate the value of and potential uses for data collected via geophysical techniques with respect to ongoing investigations related to linear infrastructure. One or more techniques, including direct-current resistivity, capacitive-coupled resistivity, and ground-penetrating radar, were evaluated at sites in continuous and discontinuous permafrost zones. Results revealed that resistivity techniques adequately differentiate between frozen and unfrozen ground, and in some instances, were able to identify individual ice wedges in a frozen heterogeneous matrix. Capacitive-coupled resistivity was found to be extremely promising due to its relative mobility as compared with direct-current resistivity. Ground-penetrating radar was shown to be useful for evaluating the factors leading to subsidence in an existing road. Taken as a whole, the study results indicate that supplemental geophysical surveys may add to the quality of a geotechnical investigation by helping to optimize the placement of boreholes. Moreover, such surveys may reduce the overall investigation costs by reducing the number of boreholes required to characterize the subsurface

Anomalous optical surface absorption in nominally pure silicon samples at 1550 nm

The announcement of the direct detection of Gravitational Waves (GW) by the LIGO and Virgo collaboration in February 2016 has removed any uncertainty around the possibility of GW astronomy. It has demonstrated that future detectors with sensitivities ten times greater than the Advanced LIGO detectors would see thousands of events per year. Many proposals for such future interferometric GW detectors assume the use of silicon test masses. Silicon has low mechanical loss at low temperatures, which leads to low displacement noise for a suspended interferometer mirror. In addition to the low mechanical loss, it is a requirement that the test masses have a low optical loss. Measurements at 1550 nm have indicated that material with a low enough bulk absorption is available; however there have been suggestions that this low absorption material has a surface absorption of > 100 ppm which could preclude its use in future cryogenic detectors. We show in this paper that this surface loss is not intrinsic but is likely to be a result of particular polishing techniques and can be removed or avoided by the correct polishing procedure. This is an important step towards high gravitational wave detection rates in silicon based instruments

Evapotranspiration in Northern Agro-Ecosystems: Numerical Simulation and Experimental Comparison

Evapotranspiration and near-surface soil moisture dynamics are key-entangled variables regulating flux at the surface-atmosphere interface. Both are central in improving mass and energy balances in agro ecosystems. However, under the extreme conditions of high-latitude soils and weather pattern variability, the implementation of such coupled liquid and vapor phase numerical simulation remain to be tested. We consider the nonisothermal solution of the vapor flux equation that accounts for the thermally driven water vapor transport and phase changes. Fully coupled flux model outputs are compared and contrasted against field measurements of soil temperature, heat flux, water content, and evaporation in a subarctic agroecosystem in Alaska. Two well-defined hydro-meteorological situations were selected: dry and wet periods. Numerical simulation was forced by time series of incoming global solar radiation and atmospheric surface layer thermodynamic parameters: surface wind speed, ambient temperature, relative humidity, precipitation, and soil temperature and soil moisture. In this simulation, soil parameters changing in depth and time are considered as dynamically adjusted boundary conditions for solving the set of coupled differential equations. Results from this evaluation give good correlation of modeled and observed data in net radiation (Rnet) (R2 of 0.92, root mean square error (RMSE) of 45 W m−2), latent heat (0.70, RMSE of 53 W m−2), and sensible heat (R2 = 0.63, RMSE = 32 W m−2) during the dry period. On the other hand, a poor agreement was obtained in the radiative fluxes and turbulent fluxes during the wet period due to the lack of representation in the radiation field and differences in soil dynamics across the landscape

Hydro-sedimentological Monitoring and Analysis for Material Sites on the Sagavanirktok River

Researchers from the Water and Environmental Research Center at the Institute of Northern Engineering, University of Alaska Fairbanks, are conducting a research project related to sediment transport conditions along the Sagavanirktok River. This report presents tasks conducted from summer 2015 to early winter 2016. Four hydrometeorological stations were installed in early July 2015 on the west bank of the river. The stations are spread out over a reach of approximately 90 miles along the Dalton Highway (from MP 405, the northernmost location, to MP 318, the southernmost location). These stations are equipped with pressure transducers and with air temperature, relative humidity, wind speed, wind direction, barometric pressure, and turbidity sensors. Cameras were installed at each station, and automatic water samplers were deployed during the open-water season. The stations have a telemetry system that allows for transmitting data in near-real time. Discharge measurements were performed three times: twice in July (early and late in the month), and once in mid-September. Measured discharges were in the order of 100 m3/s, indicating that measurements were performed during low flows. Suspended sediment concentrations ranged from 2 mg/l (nearly clear water) to 625 mg/l. The average grain size for suspended sediment from selected samples was 47.8 μm, which corresponds to silt. Vegetation was characterized at 27 plots near the stations. Measurements of basic water quality parameters, performed during winter, indicated no potential issues at the sampled locations. Dry and wet pits were excavated in the vicinity of each station. These trenches will be used to estimate average bedload sediment transport during spring breakup 2016. A change detection analysis of the period 1985–2007 along the area of interest revealed that during the present study period, the river was relatively stable.ABSTRACT ..................................................................................................................................... i LIST OF FIGURES ....................................................................................................................... iv LIST OF TABLES ......................................................................................................................... vi ACKNOWLEDGMENTS ............................................................................................................ vii DISCLAIMER .............................................................................................................................. vii CONVERSION FACTORS, UNITS, WATER QUALITY UNITS, VERTICAL AND HORIZONTAL DATUM, ABBREVIATIONS, AND SYMBOLS ........................................... viii ABBREVIATIONS, ACRONYMS, AND SYMBOLS ................................................................. x 1 INTRODUCTION AND STUDY AREA ............................................................................... 1 2 METHODOLOGY AND EQUIPMENT .............................................................................. 11 2.1 Pit Trenches .................................................................................................................... 12 2.2 Meteorology ................................................................................................................... 13 2.3 Water Level Measurements ............................................................................................ 13 2.4 Runoff............................................................................................................................. 14 2.5 Suspended Sediment ...................................................................................................... 15 2.6 Turbidity ......................................................................................................................... 15 2.7 Substrate and Floodplain Vegetation Survey ................................................................. 16 2.7.1 Site selection ........................................................................................................... 16 2.7.2 Quantifying substrate .............................................................................................. 16 2.7.3 Characterizing vegetation ....................................................................................... 17 3 RESULTS .............................................................................................................................. 19 3.1 Pit Trench Configuration ................................................................................................ 19 3.2 Meteorology ................................................................................................................... 27 3.3 Water Level Observations .............................................................................................. 27 3.4 Runoff............................................................................................................................. 31 3.4.1 Additional runoff observations ............................................................................... 31 3.5 Suspended Sediment ...................................................................................................... 32 3.6 Suspended Sediment Grain-Size Distribution ................................................................ 34 3.7 Turbidity ......................................................................................................................... 35 3.8 Water Quality ................................................................................................................. 37 4 ANALYSIS ........................................................................................................................... 39 4.1 Substrate and Vegetation ................................................................................................ 39 4.1.1 Substrate .................................................................................................................. 39 iii 4.1.2 Vegetation ............................................................................................................... 40 4.2 River Channel Stability .................................................................................................. 42 5 CONCLUSIONS ................................................................................................................... 56 6 REFERENCES ...................................................................................................................... 58 7 APPENDICES ....................................................................................................................... 6

On the performance of tensor methods for solving ill-conditioned problems.

This paper investigates the performance of tensor methods for solving small- and large-scale systems of nonlinear equations where the Jacobian matrix at the root is ill-conditioned or singular. This condition occurs on many classes of problems, such as identifying or approaching turning points in path following problems. The singular case has been studied more than the highly ill-conditioned case, for both Newton and tensor methods. It is known that Newton-based methods do not work well with singular problems because they converge linearly to the solution and, in some cases, with poor accuracy. On the other hand, direct tensor methods have performed well on singular problems and have superlinear convergence on such problems under certain conditions. This behavior originates from the use of a special, restricted form of the second-order term included in the local tensor model that provides information lacking in a (nearly) singular Jacobian. With several implementations available for large-scale problems, tensor methods now are capable of solving larger problems. We compare the performance of tensor methods and Newton-based methods for both small- and large-scale problems over a range of conditionings, from well-conditioned to ill-conditioned to singular. Previous studies with tensor methods only concerned the ends of this spectrum. Our results show that tensor methods are increasingly superior to Newton-based methods as the problem grows more ill-conditioned

Proposal for a unified nomenclature for target site mutations associated with resistance to fungicides

Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino-acid substitutions is to cite the wild type amino acid, the codon number and the new amino acid, using the one letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers. These differences in numbering arise from the different lengths of the proteins in each species. The purpose of the current paper is to propose a system for unifying the labelling of amino acids in fungicide target proteins. To do this we have produced alignments between fungicide target proteins of relevant species fitted to a well-studied “archetype” species. Orthologous amino acids in all species are then assigned numerical “labels” based on the position of the amino acid in the archetype protein

Clinical Trial of Oral Nelfinavir before and during Radiation Therapy for Advanced Rectal Cancer

Purpose Nelfinavir, a PI3-kinase pathway inhibitor, is a radiosensitizer which increases tumor blood flow in preclinical models. We conducted an early-phase study to demonstrate the safety of nelfinavir combined with hypofractionated radiotherapy (RT) and to develop biomarkers of tumor perfusion and radiosensitization for this combinatorial approach. Patients and Methods Ten patients with T3-4 N0-2 M1 rectal cancer received 7 days of oral nelfinavir (1250 mg bd) and a further 7 days of nelfinavir during pelvic RT (25 Gy/5 fractions/7 days). Perfusion CT (p-CT) and DCE-MRI scans were performed pre-treatment, after 7 days of nelfinavir and prior to last fraction of RT. Biopsies taken pre-treatment and 7 days after the last fraction of RT were analysed for tumor cell density (TCD). Results There were 3 drug-related grade 3 adverse events: diarrhea, rash, lymphopenia. On DCE-MRI, there was a mean 42% increase in median Ktrans, and a corresponding median 30% increase in mean blood flow on p-CT during RT in combination with nelfinavir. Median TCD decreased from 24.3% at baseline to 9.2% in biopsies taken 7 days after RT (P=0.01). Overall, 5/9 evaluable patients exhibited good tumor regression on MRI assessed by Tumor Regression Grade (mrTRG). Conclusions This is the first study to evaluate nelfinavir in combination with RT without concurrent chemotherapy. It has shown that nelfinavir-RT is well tolerated and is associated with increased blood flow to rectal tumors. The efficacy of nelfinavir-RT versus RT alone merits clinical evaluation, including measurement of tumor blood flow