The Production of Designed Potential Protein Contrast Agents and their Encapsulation in Albumin Microspheres

Using protein design, a series of metal binding proteins have been designed, allowing the local factors that contribute to metal affinity and thermostability to be studied. Those proteins with the highest metal binding affinities had the lowest apo-form Tm and the largest ÄTm upon metal binding. In this thesis, major steps have been taken toward applying the engineered protein to MR imaging. The progress of magnetic resonance imaging is hindered by low specificity and rapid elimination of FDA-approved MRI contrast agents. The engineered protein contrast agent has been conjugated to a cancer-specific targeting peptide and encapsulated in albumin microspheres to provide tandem passive and active tumor targeting. Also, a simple, high-yield purification method has been developed

Immobilization of Scandium and Other Chemical Elements in Systems with Aquatic Macrophyte

The possibility of immobilization of scandium and other chemical elements by biogenic materialsderived from an aquatic macrophyte was explored. The concentrations of scandium and some other chemicalelements were measured in the dried biomass (mortmass) of aquatic plants Myriophyllum aquaticum. In theexperiments, the mortmass was incubated in aquatic systems where some chemical elements were added to theaquatic medium. After the incubation, the concentrations of these chemical elements in the mortmass weremeasured using inductively coupled plasma atomic emission spectroscopy (ICP-AES), also referred to asinductively coupled plasma optical emission spectrometry (ICP-OES). Increases in the concentrations ofscandium and some other chemical elements (Ce, In, Se, Ru, Pd, U, and Zr) were observed in the biogenic materia

Study of the Interactions between Elodea canadensis and CuO Nanoparticles

Copper is one of the key heavy metals that pollute environment and constitute a serious threat to thehealth of humans and ecosystems. Copper may enter the aquatic environment in both soluble and nanoparticleform. It was previously found in a series of studies that nanoparticles, including those of several metal oxides,exercise both negative and positive effects on the higher plants which makes necessary further research on theinteraction between metal oxide nanoparticles and plants. Interactions between aquatic plants and copper–containingnanoparticles were not suffi ciently studied. The goal of this study was to contribute to the investigation of theinteractions between CuO nanoparticles and the aquatic plant Elodea canadensis under the conditions of experimentalmicrocosms. It was found that CuO nanoparticles demonstrated some phytotoxicity to Elodea canadensis.After the incubation of Elodea canadensis in the aquatic medium contaminated with CuO nanoparticles there wasa signifi cant increase (by two orders of magnitude) of the concentration of copper in the biomass of the plants

Implementing Welfare-to-Work Services: A Study of Staff Decision-Making

Copyright 2006 Alliance for Children and FamiliesIn the post-welfare reform era, increased discretion has been given to frontline staff for day-today welfare policy implementation. To determine how frontline staff address the complex needs of welfare program participants in this new policy environment, the decision-making processes of welfare staff (N = 52) in 11 San Francisco Bay Area county social service agencies were assessed through a case vignette using a Web-based survey design. We examined staff decision making in four areas: problem recognition, goal formulation, information search processes, and evaluation. The results suggest that the high level o f staff discretion apparent in the day-to-day implementation of welfare policy may have important implications for participants. Several recommendations for policy, practice, and future research are presented

Dynamical Imaging with Interferometry

By linking widely separated radio dishes, the technique of very long baseline interferometry (VLBI) can greatly enhance angular resolution in radio astronomy. However, at any given moment, a VLBI array only sparsely samples the information necessary to form an image. Conventional imaging techniques partially overcome this limitation by making the assumption that the observed cosmic source structure does not evolve over the duration of an observation, which enables VLBI networks to accumulate information as the Earth rotates and changes the projected array geometry. Although this assumption is appropriate for nearly all VLBI, it is almost certainly violated for submillimeter observations of the Galactic Center supermassive black hole, Sagittarius A* (Sgr A*), which has a gravitational timescale of only ~20 seconds and exhibits intra-hour variability. To address this challenge, we develop several techniques to reconstruct dynamical images ("movies") from interferometric data. Our techniques are applicable to both single-epoch and multi-epoch variability studies, and they are suitable for exploring many different physical processes including flaring regions, stable images with small time-dependent perturbations, steady accretion dynamics, or kinematics of relativistic jets. Moreover, dynamical imaging can be used to estimate time-averaged images from time-variable data, eliminating many spurious image artifacts that arise when using standard imaging methods. We demonstrate the effectiveness of our techniques using synthetic observations of simulated black hole systems and 7mm Very Long Baseline Array observations of M87, and we show that dynamical imaging is feasible for Event Horizon Telescope observations of Sgr A*.Comment: 16 Pages, 12 Figures, Accepted for publication in Ap

Dietary nitrate increases arginine availability and protects mitochondrial complex I and energetics in the hypoxic rat heart

This is the final version. It was first published by Wiley in The Journal of Physiology at http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2014.275263/abstract.Hypoxic exposure is associated with impaired cardiac energetics in humans and altered mitochondrial function, with suppressed complex I-supported respiration, in rat heart. This response might limit reactive oxygen species (ROS) generation, but at the cost of impaired electron transport chain (ETC) activity. Dietary nitrate supplementation improves mitochondrial efficiency and can promote tissue oxygenation by enhancing blood flow. We therefore hypothesised that ETC dysfunction, impaired energetics and oxidative damage in the hearts of rats exposed to chronic hypoxia could be alleviated by sustained administration of a moderate dose of dietary nitrate. Male Wistar rats (n=40) were given water supplemented with 0.7 mmol/L NaCl (as control) or 0.7 mmol/L NaNO3, elevating plasma nitrate levels by 80%, and were exposed to 13% O2 (hypoxia) or normoxia (n=10 per group) for 14 days. Respiration rates, ETC protein levels, mitochondrial density, ATP content and protein carbonylation were measured in cardiac muscle. Complex I respiration rates and protein levels were 33% lower in hypoxic/NaCl rats compared with normoxic/NaCl controls. Protein carbonylation was 65% higher in hearts of hypoxic rats compared with controls, indicating increased oxidative stress, whilst ATP levels were 62% lower. Respiration rates, complex I protein and activity, protein carbonylation and ATP levels were all fully protected in the hearts of nitrate-supplemented hypoxic rats. Both in normoxia and hypoxia, dietary nitrate suppressed cardiac arginase expression and activity and markedly elevated cardiac L-arginine concentrations, unmasking a novel mechanism of action by which nitrate enhances tissue NO bioavailability. Dietary nitrate therefore alleviates metabolic abnormalities in the hypoxic heart, improving myocardial energetics

Expression profiling of zebrafish sox9 mutants reveals that Sox9 is required for retinal differentiation

AbstractThe transcription factor gene Sox9 plays various roles in development, including differentiation of the skeleton, gonads, glia, and heart. Other functions of Sox9 remain enigmatic. Because Sox9 protein regulates expression of target genes, the identification of Sox9 targets should facilitate an understanding of the mechanisms of Sox9 action. To help identify Sox9 targets, we used microarray expression profiling to compare wild-type embryos to mutant embryos lacking activity for both sox9a and sox9b, the zebrafish co-orthologs of Sox9. Candidate genes were further evaluated by whole-mount in situ hybridization in wild-type and sox9 single and double mutant embryos. Results identified genes expressed in cartilage (col2a1a and col11a2), retina (calb2a, calb2b, crx, neurod, rs1, sox4a and vsx1) and pectoral fin bud (klf2b and EST AI722369) as candidate targets for Sox9. Cartilage is a well-characterized Sox9 target, which validates this strategy, whereas retina represents a novel Sox9 function. Analysis of mutant phenotypes confirmed that Sox9 helps regulate the number of Müller glia and photoreceptor cells and helps organize the neural retina. These roles in eye development were previously unrecognized and reinforce the multiple functions that Sox9 plays in vertebrate development

Pillars of Growth in Nebraska\u27s Non-Metropolitan Economy

Agriculture is a critical part of Nebraska’s economy, and changes in the fortunes of agriculture play an important role in the success of the state’s non-metropolitan regions. Trends toward consolidation and rising productivity in agriculture, however, have raised concerns about the future of non-metropolitan Nebraska. Some citizens and policymakers have begun to wonder if the economy can create sufficient job opportunities for non-metropolitan residents. The answer to this question depends not only upon the relative strength of the agricultural sector, but also upon the presence of other industries that can join agriculture as pillars for employment growth in non-metropolitan Nebraska. This study, sponsored by the University of Nebraska Rural Initiative, brings together researchers from the University of Nebraska–Lincoln, the University of Nebraska at Omaha, and Creighton University to examine multiple dimensions of Nebraska’s non-metropolitan economy. In addition to agriculture, we will examine the fortunes of five other key industries: 1) manufacturing, 2) tourism, 3) trucking, 4) professional and technical services, and 5) information. This list contains industries that are traditional areas of rural economic development such as manufacturing, agriculture, and tourism, but also includes rapidly expanding industries in our state (trucking) or industries within a rapidly changing national economy (professional and technical services and information). National economic forecasts suggest that industries such as trucking, tourism, professional and technical services, and information will continue to add employment at a moderate to rapid pace over the next decade

Inverse tuning of metal binding affinity and protein stability by altering charged coordination residues in designed calcium binding proteins

Ca2+ binding proteins are essential for regulating the role of Ca2+ in cell signaling and maintaining Ca2+ homeostasis. Negatively charged residues such as Asp and Glu are often found in Ca2+ binding proteins and are known to influence Ca2+ binding affinity and protein stability. In this paper, we report a systematic investigation of the role of local charge number and type of coordination residues in Ca2+ binding and protein stability using de novo designed Ca2+ binding proteins. The approach of de novo design was chosen to avoid the complications of cooperative binding and Ca2+-induced conformational change associated with natural proteins. We show that when the number of negatively charged coordination residues increased from 2 to 5 in a relatively restricted Ca2+-binding site, Ca2+ binding affinities increased by more than 3 orders of magnitude and metal selectivity for trivalent Ln3+ over divalent Ca2+ increased by more than 100-fold. Additionally, the thermal transition temperatures of the apo forms of the designed proteins decreased due to charge repulsion at the Ca2+ binding pocket. The thermal stability of the proteins was regained upon Ca2+ and Ln3+ binding to the designed Ca2+ binding pocket. We therefore observe a striking tradeoff between Ca2+/Ln3+ affinity and protein stability when the net charge of the coordination residues is varied. Our study has strong implications for understanding and predicting Ca2+-conferred thermal stabilization of natural Ca2+ binding proteins as well as for designing novel metalloproteins with tunable Ca2+ and Ln3+ binding affinity and selectivity

Improving predictions of critical shear stress in gravel bed rivers: Identifying the onset of sediment transport and quantifying sediment structure

Understanding when gravel moves in river beds is essential for a range of different applications but is still surprisingly hard to predict. Here we consider how our ability to predict critical shear stress (τ c ) is being improved by recent advances in two areas: (1) identifying the onset of bedload transport; and (2) quantifying grain‐scale gravel bed structure. This paper addresses these areas through both an in‐depth review and a comparison of new datasets of gravel structure collected using three different methods. We focus on advances in these two areas because of the need to understand how the conditions for sediment entrainment vary spatially and temporally, and because spatial and temporal changes in grain‐scale structure are likely to be a major driver of changes in τ c . We use data collected from a small gravel‐bed stream using direct field‐based measurements, terrestrial laser scanning (TLS) and computed tomography (CT) scanning, which is the first time that these methods have been directly compared. Using each method, we measure structure‐relevant metrics including grain size distribution, grain protrusion and fine matrix content. We find that all three methods produce consistent measures of grain size, but that there is less agreement between measurements of grain protrusion and fine matrix content