Empirical Data of the Metal-Ferroelectric-Semiconductor Field Effect Transistor Polarization and Channel Resistance for Timing and Retention Analysis

In this paper, empirical data describing the channel resistance and polarization of several metal-ferroelectric-semiconductor field-effect transistors (MFSFETs) is presented. Various channel length and width transistors were used to describe the channel resistance under various biasing conditions and in both positive and negative polarization states. The presented results and analysis provide insight into the switching speed between polarization states as well as the timing and retention constraints for a given set of device dimensions. This is of particular value when considering circuit designs that utilize MFSFETs, especially digital memory circuits.     

Mechanisms of TDP-43 Proteinopathy Onset and Propagation

TDP-43 is an RNA-binding protein that has been robustly linked to the pathogenesis of a number of neurodegenerative disorders, including amyotrophic lateral sclerosis and frontotemporal dementia. While mutations in the TARDBP gene that codes for the protein have been identified as causing disease in a small subset of patients, TDP-43 proteinopathy is present in the majority of cases regardless of mutation status. This raises key questions regarding the mechanisms by which TDP-43 proteinopathy arises and spreads throughout the central nervous system. Numerous studies have explored the role of a variety of cellular functions on the disease process, and nucleocytoplasmic transport, protein homeostasis, RNA interactions and cellular stress have all risen to the forefront as possible contributors to the initiation of TDP-43 pathogenesis. There is also a small but growing body of evidence suggesting that aggregation-prone TDP-43 can recruit physiological TDP-43, and be transmitted intercellularly, providing a mechanism whereby small-scale proteinopathy spreads from cell to cell, reflecting the spread of clinical symptoms observed in patients. This review will discuss the potential role of the aforementioned cellular functions in TDP-43 pathogenesis, and explore how aberrant pathology may spread, and result in a feed-forward cascade effect, leading to robust TDP-43 proteinopathy and disease.     

Airflow Around a Child-Size Manikin in a Low-Speed Wind Environment

This work provides an understanding of how airflow patterns around humans can affect the concentrations and particle size distributions of particulate matter (PM) in the breathing zone. The focus of the experiments reported here is the flow around a child-size manikin under various conditions, including changes in body heat, breathing, wind speed, and body orientation relative to the wind direction. The airflow patterns that develop were investigated using laser Doppler anemometry. The presence of body heat changes the flow pattern most dramatically. With the manikin at room temperature, the flow pattern on the downstream side of the manikin consists of two slowly recirculating eddies. With the addition of body heat to the manikin, the flow pattern downstream of the manikin changes to a rising vertical plume with velocities on the order of 0.1 m/s. This vertical plume is capable of transporting PM into the breathing zone from near the floor. Increased wind speed decreases the relative importance of buoyancy. As the wind speed increases from 0.1 to 0.3 m/s, the vertical plume on the downstream side of the manikin is replaced by two recirculating eddies, a flow pattern similar to that with the unheated manikin. Changes in the relative importance of body heat and free-stream wind speed are quantified using a type of Richardson number.     

Reducing Uncertainty in Site Characterization Using Bayes Monte Carlo Methods

A Bayesian uncertainty analysis approach is developed as a tool for assessing and reducing uncertainty in ground-water flow and chemical transport predictions. The method is illustrated for a site contaminated with chlorinated hydrocarbons. Uncertainty in source characterization, in chemical transport parameters, and in the assumed hydrogeologic structure was evaluated using engineering judgment and updated using observed field data. The updating approach using observed hydraulic head data was able to differentiate between reasonable and unreasonable hydraulic conductivity fields but could not differentiate between alternative conceptual models for the geological structure of the subsurface at the site. Updating using observed chemical concentration data reduced the uncertainty in most parameters and reduced uncertainty in alternative conceptual models describing the geological structure at the site, source locations, and the chemicals released at these sources. Thirty-year transport projections for no-action and source containment scenarios demonstrate a typical application of the methods.     

Subtleties in Perception and Discrimination by Cabbage Looper Moths, Trichoplusia ni, of the two 14-carbon Acetate Sex Pheromone Components

Three compounds that are emitted by virgin female cabbage looper moths, Trichoplusia ni, (Z)-7-dodecenyl acetate (Z7–12:Ac), (Z)-7-tetradecenyl acetate (Z7–14:Ac), and (Z)-9-tetradecenyl acetate (Z9–14:Ac), are detected by antennal olfactory receptor neurons specialized to detect sex pheromone components. The principal evidence signifying that either or both of Z7–14:Ac and Z9–14:Ac have an effect on male behavior comes from an observed reduction in the numbers of males trapped by Z7–12:Ac paired with a six-component mixture. The evidence conforms to a hypothesis that either or both of these compounds are the basis for discrimination between the two mixtures. However, scant evidence for this hypothesis was obtained in paired-source laboratory wind-tunnel assays, even at airborne concentrations of Z7–14:Ac and Z9–14:Ac that ranged up to 1000× that emitted by a female. Furthermore, there was little evidence from single-source laboratory or field trap assays confirming that Z7–14:Ac and Z9–14:Ac at or above natural stimulus strengths modify the moth's perception of Z7–12:Ac. The data suggest that discrimination of small mixture differences may not be resolvable within the confines of a wind tunnel.     

Meshless analysis of steady-state electro-osmotic transport

An emerging technology in the area of microsystems is micro-total analysis systems (μTAS) for biological sample analysis. We have simulated electro-osmosis-a common transport mechanism within these devices-by developing meshless techniques. Numerical simulation of electro-osmotic transport requires the solution of the Laplace equation, the Poisson-Boltzmann equation and the incompressible Stokes or Navier-Stokes equations. We describe the development and implementation of meshless techniques for all the governing equations. In particular we introduce a stabilized Stokes solver for very-low Reynolds number flows and a multistep Navier-Stokes solver for a wide range of Reynolds number flows. We have analyzed electro-osmotic transport in three geometries typically encountered in biological devices: a straight channel, a cross-shaped intersection, and a T-shaped intersection     

The Statistics of Electron Trapping Processes in Microcrystals of Silver Halides*

The probability for the direct trapping of electrons from the conduction band of microcrystals of silver halides is calculated as a function of volume, temperature, and depth and number of traps per microcrystal. For grains with a volume of 4 µm³ at 298 K, and a small number of trapping stales, it is shown that the trap depth must be greater than 0.4.1 eV for there to be a significant trapping probability. The condition for electron trapping is thatE_t> kT In Z, where E_t is the trap depth and Z the partition function for the conduction electrons. Individual sites with trap depths less than 0.05eV have a negligible probability for trapping electrons at room temperature. The implications of these results for theories of latent image formation and of spectral sensitization and desensitization are discussed.