Manipulation of the Electrical Double Layer for Control and Sensing in a Solid State Nanopore

Nanopores have been explored with the goal of achieving non-functionalized, sub-molecular sensors, primarily with the purpose of producing fast, low-cost DNA sequencers. Because of the nanoscale volume within the nanopore structure, it is possible to isolate individual molecular and sub-molecular analytes. Nanopore DNA sequencing has remained elusive due to high noise levels and the challenge of obtaining single-nucleotide resolution. However, the complete electrical double layer within the nanopore is a key feature of fluid-nanopore interaction and has been neglected in previous studies. By exploring interactions with the electrical double layer in various nanopore systems, we characterize the material, electrical, and solution dependent properties of this structure and develop a new sensing technique. The overall goals of this project are development of a theoretically complete and useful model of the electrical double layer in a nanopore, development of a nanopore device capable of detecting and manipulating the electrical double layer, characterization of active nanofluidic control, and detection of molecular and double layer properties. By considering extensive numerical models along with experimental evaluation of the nanopore devices, we characterize the fluidic and sensor properties of the electrical double layer in a nanopore. The ability to interact with the electrochemical and structural properties of the fluid within a nanopore offers new avenues for molecular detection and manipulation. We find that the energetic balance between the nanopore surface potential and the distribution of charged species within the electrical double layer is the key relationship governing the operation of this type of device. A method of active control of the ionic conductance through the nanopore was developed, with complete gating and on-state modulation. A molecular sensing technique was developed by correlating changes to the electrochemical potential of the solution to the physical properties of molecular analytes. The theoretical and practical limits of the nanopore sensor were tested by implementing a new type of nanopore DNA sequencer. High accuracy DNA sequences were produced by combining the double layer potential and ionic current channels in parallel, along with extensive application of signal theory, digital signal processing, and machine learning techniques

The Survival and Recovery of ϕ6 Virus from Fomites

Viral transmission from the environment can occur via fomites, but there is uncertainty about which factors most affect viral persistence on fomites. Children are a population highly susceptible to viral infection, and sharing common fomites like toys may spread infection. The objective of this research was to assess the survival of enveloped viruses on the surfaces of children’s toys, using bacteriophage ϕ6 as a surrogate for enveloped human viruses. The survival of infectious ϕ6 virions was observed over a 24 hour period at 22°C and relative humidities of 40% & 60%. On the surface of children’s toys, ϕ6 was better able to persist at 60% RH (log10 reduction\u3c 2 log10) over a 24 hour period than it was at 40% RH (log10 reduction\u3e 6 log10). If ϕ6 virus persists on toy material for up to 24 hours, then viral transmission via shared fomites is certainly significant

Numerical solution of the Navier-Stokes equations for arbitrary two-dimensional multi-element airfoils

The development of a numerical simulation of time dependent, turbulent, compressible flow about two dimensional multi-element airfoils of arbitrary shape is described. The basis of this simulation is a technique of automatic numerical generation of coordinate systems fitted to the multiple bodies regardless of their number or shape. Procedures developed whereby the coordinate lines are automatically concentrated in the boundary layer at any Reynolds number are discussed. The compressible turbulent solution involves an algebraic eddy viscosity turbulence model. The laminar version was run for transonic flow at free stream Mach numbers up to 0.9

Attention to Social Comparison Information: An Individual Difference Factor Affecting Consumer Conformity

Interpersonal influence in consumer behavior is moderated by the extent of consumer sensitivity to social comparison information concerning product purchase and usage behavior (cf. Calder and Burnkrant 1977). Two survey studies indicate that Lennox and Wolfe\u27s (1984) attention-to-social-comparison-information (AT-SCI) scale has adequate convergent and discriminant validity and moderates the relative influence of normative consequences on behavioral intentions, as predicted. A quasi-experiment and an experiment in which control subjects under no social pressure are compared with high and low ATSCI subjects under pressure reveal that high ATSCI subjects are more likely to comply with normative pressures

Cases and Materials on Water Law

This new edition begins by covering the long-established systems of private water rights (the appropriation doctrine and the riparian doctrine for surface waters and the various doctrines for groundwaters). Then it covers public rights, water quality regulation, and other environmental regulation primarily from the perspective of how these affect private water rights. The book also addresses interstate allocation and federal-state relations. There is one new principal case and many new notes. The notes in all the chapters have been updated.https://scholarlycommons.pacific.edu/facultyteaching/1031/thumbnail.jp

Connectivity-enhanced diffusion analysis reveals white matter density disruptions in first episode and chronic schizophrenia.

Reduced fractional anisotropy (FA) is a well-established correlate of schizophrenia, but it remains unclear whether these tensor-based differences are the result of axon damage and/or organizational changes and whether the changes are progressive in the adult course of illness. Diffusion MRI data were collected in 81 schizophrenia patients (54 first episode and 27 chronic) and 64 controls. Analysis of FA was combined with "fixel-based" analysis, the latter of which leverages connectivity and crossing-fiber information to assess both fiber bundle density and organizational complexity (i.e., presence and magnitude of off-axis diffusion signal). Compared with controls, patients with schizophrenia displayed clusters of significantly lower FA in the bilateral frontal lobes, right dorsal centrum semiovale, and the left anterior limb of the internal capsule. All FA-based group differences overlapped substantially with regions containing complex fiber architecture. FA within these clusters was positively correlated with principal axis fiber density, but inversely correlated with both secondary/tertiary axis fiber density and voxel-wise fiber complexity. Crossing fiber complexity had the strongest (inverse) association with FA (r = -0.82). When crossing fiber structure was modeled in the MRtrix fixel-based analysis pipeline, patients exhibited significantly lower fiber density compared to controls in the dorsal and posterior corpus callosum (central, postcentral, and forceps major). Findings of lower FA in patients with schizophrenia likely reflect two inversely related signals: reduced density of principal axis fiber tracts and increased off-axis diffusion sources. Whereas the former confirms at least some regions where myelin and or/axon count are lower in schizophrenia, the latter indicates that the FA signal from principal axis fiber coherence is broadly contaminated by macrostructural complexity, and therefore does not necessarily reflect microstructural group differences. These results underline the need to move beyond tensor-based models in favor of acquisition and analysis techniques that can help disambiguate different sources of white matter disruptions associated with schizophrenia

An Attributional Analysis of Resistance to Group Pressure Regarding Illicit Drug and Alcohol Consumption

This article investigates the role of attributional thinking in generating resistance to pressures toward conformity in the illicit consumption of drugs and alcohol. The results of four studies regarding how conformity influences illicit drug and alcohol consumption among high school and college students are reported. In study 1 more than two-thirds of the respondents reported concern for the implications of their own dissent or compliance regarding the reactions of their peers. Study 2 demonstrated a significant relationship between high school students\u27 attributional thinking concerning a peer group\u27s illicit beer consumption and conformity, expressed as intentions to drink the beer. In study 3, in-depth interviews with high school students provided insight into the realism of the conformity scenarios used in the research and the types of conformity pressures experienced by young people. In study 4, locus of causality, an abstract attributional dimension, and several specific attributions were shown to be significantly associated with conformity in the consumption of marijuana