Rapid degradation of FAD following lysis of Neurospora crassa cells: Consequences for evaluation of flavin composition in vivo.

Rapid degradation of FAD following lysis of Neurospora crassa cells: Consequences for evaluation of flavin composition in vivo

Experimental Data on High Power Explosive Opening and Closing Switches at CEM-UT

The need for high power switching i n pulse power research has lead to the development of fast acting opening and closing switches with current capacity of more than 1 MA. Presented is the performance data of two switches developed for railgun experiments at the Center for Electromechanics at The University of Texas at Austin (CEM-UT). The first is a compact closing switch, explosively actuated, used as an isolation device for staging parallel inductors charged by homopolar generators (HPGs) and as a crowbar to shunt excess energy from railguns during projectile exit .The second i s an explosive opening switch which provides a low resistance path during inductor charging before quickly opening to transfer energy to the railgun.Center for Electromechanic

A computational framework to emulate the human perspective in flow cytometric data analysis

Background: In recent years, intense research efforts have focused on developing methods for automated flow cytometric data analysis. However, while designing such applications, little or no attention has been paid to the human perspective that is absolutely central to the manual gating process of identifying and characterizing cell populations. In particular, the assumption of many common techniques that cell populations could be modeled reliably with pre-specified distributions may not hold true in real-life samples, which can have populations of arbitrary shapes and considerable inter-sample variation. <p/>Results: To address this, we developed a new framework flowScape for emulating certain key aspects of the human perspective in analyzing flow data, which we implemented in multiple steps. First, flowScape begins with creating a mathematically rigorous map of the high-dimensional flow data landscape based on dense and sparse regions defined by relative concentrations of events around modes. In the second step, these modal clusters are connected with a global hierarchical structure. This representation allows flowScape to perform ridgeline analysis for both traversing the landscape and isolating cell populations at different levels of resolution. Finally, we extended manual gating with a new capacity for constructing templates that can identify target populations in terms of their relative parameters, as opposed to the more commonly used absolute or physical parameters. This allows flowScape to apply such templates in batch mode for detecting the corresponding populations in a flexible, sample-specific manner. We also demonstrated different applications of our framework to flow data analysis and show its superiority over other analytical methods. <p/>Conclusions: The human perspective, built on top of intuition and experience, is a very important component of flow cytometric data analysis. By emulating some of its approaches and extending these with automation and rigor, flowScape provides a flexible and robust framework for computational cytomics

PIP3-dependent macropinocytosis is incompatible with chemotaxis

In eukaryotic chemotaxis, the mechanisms connecting external signals to the motile apparatus remain unclear. The role of the lipid phosphatidylinositol 3,4,5-trisphosphate (PIP3) has been particularly controversial. PIP3 has many cellular roles, notably in growth control and macropinocytosis as well as cell motility. Here we show that PIP3 is not only unnecessary for Dictyostelium discoideum to migrate toward folate, but actively inhibits chemotaxis. We find that macropinosomes, but not pseudopods, in growing cells are dependent on PIP3. PIP3 patches in these cells show no directional bias, and overall only PIP3-free pseudopods orient up-gradient. The pseudopod driver suppressor of cAR mutations (SCAR)/WASP and verprolin homologue (WAVE) is not recruited to the center of PIP3 patches, just the edges, where it causes macropinosome formation. Wild-type cells, unlike the widely used axenic mutants, show little macropinocytosis and few large PIP3 patches, but migrate more efficiently toward folate. Tellingly, folate chemotaxis in axenic cells is rescued by knocking out phosphatidylinositide 3-kinases (PI 3-kinases). Thus PIP3 promotes macropinocytosis and interferes with pseudopod orientation during chemotaxis of growing cells

Thermoplastic applications for pulse power alternators

The field coil is the primary component of the rotor assembly that provides the rotating magnetic field for the pulse power alternator. The design of the field coil is optimized so that it will produce the required magnetic field with minimum transient losses. The high currents required to produce the correct amp-turns, along with the mechanical loads due to high rotational speeds, present further design requirements for selection of field coil material, insulation, and surrounding material that completes the matrix of the field coil sub-assembly. With the addition of active cooling requirements in the field coil design, surrounding materials must be selected that retain electrically insulative properties and are thermally conductive to allow sufficient heat removal from the field coil. Thermoplastics are now being reviewed to replace traditional glass-epoxy potting compounds (thermosets) that have been used extensively in pulsed alternator designs. Fillers can be added to tailor properties of the thermoplastic, such as ceramics to increase thermal conductivity at the cost of an increase in density. Thermal analyses have been performed that show the benefits of using thermally conductive potting compounds. In addition, subscale field coil mockups (motorettes) have been encapsulated and tested to demonstrate encapsulation of current field coil geometriesCenter for Electromechanic

Investigation of Windage Splits in an Enclosed test Fixture having a High Speed Composite Rotor in Low air Pressure Environments

The University of Texas at Austin Center for Electromechanics (UT-CEM) has designed and conducted a series of composite rotor spin tests to measure the windage losses and temperature distributions of a test setup at high rotor speeds and low air pressures. The intent of the windage tests is to validate the windage loss predictions and investigate how the air-gap windage is distributed between the rotor and stator. The findings of the spin tests will then be used to perform windage-related thermal design and analysis of a high-speed electrical machine. The radial air-gap flows under the test conditions, a low rotor cavity air pressure of 1 torr and high rotor surface velocities of 333 and 614 m/s, were in a laminar flow regime. Transient rotor and stator finite-element thermal analyses, using the measured windage losses and predicted laminar-flow windage splits, have been carried out to analyze the rotor and stator temperature distributions. This paper shows the detailed thermal analysis and compares the predictions with the measurements. The predicted and measured transient rotor and stator temperatures are in good agreement.Center for Electromechanic

Time as an operator/observable in nonrelativistic quantum mechanics

The nonrelativistic Schroedinger equation for motion of a structureless particle in four-dimensional space-time entails a well-known expression for the conserved four-vector field of local probability density and current that are associated with a quantum state solution to the equation. Under the physical assumption that each spatial, as well as the temporal, component of this current is observable, the position in time becomes an operator and an observable in that the weighted average value of the time of the particle's crossing of a complete hyperplane can be simply defined: ... When the space-time coordinates are (t,x,y,z), the paper analyzes in detail the case that the hyperplane is of the type z=constant. Particles can cross such a hyperplane in either direction, so it proves convenient to introduce an indefinite metric, and correspondingly a sesquilinear inner product with non-Hilbert space structure, for the space of quantum states on such a surface. >... A detailed formalism for computing average crossing times on a z=constant hyperplane, and average dwell times and delay times for a zone of interaction between a pair of z=constant hyperplanes, is presented.Comment: 31 pages, no figures. Differs from published version by minor corrections and additions, and two citation