GaAs FET demodulator and down-convertor for optical-microwave links

A single-gate GaAs FET is utilised to simultaneously perform the photodetection and down-conversion functions of an optical-microwave link receiver, with the transistor supplying its own local oscillator signal through self-oscillation and harmonic generation. Operation up through 89 GHz is demonstrated.     

Design, Fabrication, and Testing of a Hybrid CMOS/PDMS Microsystem for Cell Culture and Incubation

We discuss the design, fabrication, and testing of a hybrid microsystem for stand-alone cell culture and incubation. The micro-incubator is engineered through the integration of a silicon CMOS die for the heater and temperature sensor, with multilayer silicone (PDMS) structures namely, fluidic channels and a 1.5-mm diameter 12-muL culture well. A 90-mum-thick PDMS membrane covers the top of the culture well, acting as barrier to contaminants while at the same time allowing the cells to breath and exchange gases with the ambient environment. The packaging for the microsystem includes a flexible polyimide electronic ribbon cable and four fluidic ports that provide external interfaces to electrical energy, closed-loop sensing and electronic control as well as solid and liquid supplies. The complete structure has a size of (2.5times2.5times0.6) cm³. We have employed the device to successfully culture BHK-21 cells autonomously over a three day period in ambient environment     

Preparation and soft lithographic printing of nano-sized ITO-dispersions for the manufacture of electrodes for TFTs

The production of printed electronics exhibits an enormous economical potential due to the possibility to manufacture innovative products at low cost. At the moment, one of the major challenges for the fabrication of printed electronics is the controllability of the material properties during processing and the miniaturization of the deposited structures. In this context, the application of soft lithographic techniques appears promising, because they allow a defined patterning of the materials in the range of few nanometers, which is far below the limits of other printing techniques like inkjet-printing or screen printing. This work proves the applicability of the soft lithographic technique micro-molding in capillaries (MIMIC) for the manufacture of conductive indium tin oxide (ITO) electrodes. For the creation of stable dispersions of ITO nano-sized particles, steric as well as electrostatic stabilization concepts are applied. The prepared dispersions are characterized with regard to the later processing via MIMIC. The geometry and the electrical properties of the soft lithographically deposited structures are determined to prove their functionality. Special attention is paid to the influence of the wetting behavior of the dispersions on the resulting geometry of the structures. Finally, the applicability of the optimized structures is demonstrated by the assembly of a thin film transistor (TFT), in which the deposited structures serve as source and drain electrodes.     

Using RABiTS to fabricate high-temperature superconducting wire

In order for many large-scale bulk applications of high-temperature superconducting materials to be realized, the cost/performance of the superconductors needs to be optimized. From a performance standpoint, a long, flexible, single-crystal-like wire is required; from a cost-and-fabrication standpoint, an industrially scalable, low-cost process is required. Both of these critical requirements are met by rolling-assisted biaxially textured substrates, a conductor-fabrication technique that employs simple, scalable, thermomechanical processing techniques to obtain a near-single-crystal-like, flexible metal substrate in arbitrary lengths on which epitaxial oxide buffer layers and superconductors are then deposited. For more information, contact A. Goyal, Oak Ridge National Laboratory, P.O. Box 2008, MS 6116, Oak Ridge, Tennessee 37831; (423) 574-1587; fax (423) 574-7659.     

Intra-axial endophytic tumors in the pons and/or medulla oblongata. I. Symptoms, neuroradiological findings, and histopathology in 30 children

Between August 1987 and June 1994 we operated upon 30 consecutive children suffering from endophytic intra-axial tumors located in the pons and/or medulla oblongata. We present the clinical findings, neuroradiological aspects and histopathological results recorded in these cases. Diagnostic tests included clinical examinations, neurophysiological tests and neuroradiological imaging [magnetic resonance tomography (MRT) in all cases, often combined with cranial computer tomography (CCT)]. The diagnosis was confirmed by histopathological examination of the tumor material obtained by open surgical exploration in all cases. We conclude that a short history and more horizontal growth within the pons are more valuable predictors of the histopathology than differentiation between focal or diffuse growth patterns. MRT has little predictive value for histopathological diagnosis in intra-axial brain stem tumors.     

A slow wave investigation of working memory biases in mood disorders.

Mood-congruent working memory biases were examined in a delayed matching to sample paradigm using the slow wave (SW) event-related brain potential (ERP) component. Mood-congruent working memory biases, indexed by SW amplitudes, were demonstrated among individuals experiencing a major depressive episode (MDE) and nondepressed controls but not individuals with dysthymia. However, analyses of symptom severity demonstrated that those with dysthymia exhibited significantly less negative SW amplitudes with increasing depressive mood severity, whereas individuals with major depression demonstrated more negative SW amplitudes with increasing depressive mood severity. These results are discussed in the context of diagnostic specificity for cognitive biases associated with working memory of mood-disordered individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and Management of Subsurface Horizontal Drainage to Reduce Salt Loads

Many irrigated areas have shallow water tables creating waterlogging and salinization problems. This has often been controlled by installation of subsurface horizontal pipe drainage; however, these systems export large amounts of salt off farm in the drainage effluent. Improved design and management of subsurface drainage systems to reduce drainage salt loads were tested in a replicated field experiment. Deep, widely spaced drains allowed to flow without control were compared to drains with management to reduce drain flow. These were also compared with shallow, closely spaced drains that protected the root zone only and an undrained control. The deep drains flowed continuously during the two irrigation seasons with an electrical conductivity of around 11 dS∕m resulting in a drainage salt load of 5,867 kg∕ha. The management measures reduced drainage volume and salinity resulting in a 50% reduction in salt load. The shallow drains only flowed directly after an irrigation or rainfall event with low salinity, around 2 dS∕m, resulting in a 95% reduction in salt load. This showed that by management there is great potential for reducing salt mobilization in existing drainage systems, and for new systems shallower drains will minimize salt loads.     

Projection or Persuasive Press? Contrary Effects of Personal Opinion and Perceived News Coverage on Estimates of Public Opinion

This study explores the effects of personal opinion and perceived media content on individuals' assessments of public opinion, as well as the curious phenomenon that, although people perceive public agreement with their own point of view, they tend to see press coverage as disagreeable. One hypothesis, based on theories of projection of personal opinion, predicts that people will see public opinion as much like their own, but a contrary outcome is suggested by 2 interrelated hypotheses, the hostile media effect and the persuasive press inference. Data were collected on 4 issues from a large, representative national sample and provided evidence for all 3 effects. Projection received the most consistent support, but findings indicate that this assimilation effect can be substantially offset by media coverage seen as both disagreeable and influential.