A technique for monitoring SO2 in combustion exhausts: Use of a non-Nernstian sensing element in combination with an upstream catalytic filter

Detection of sulfur dioxide (SO₂) at high temperature (600–750 °C) in the presence of some interferents found in combustion exhausts (NO₂, NO, CO₂, CO, and hydrocarbon (C₃H₆)) is described. The detection scheme involves use of a catalytic filter in front of a non-Nernstian (mixed-potential) sensing element. The catalytic filter was a Ni:Cr powder bed operating at 850 °C, and the sensing elements were pairs of platinum (Pt) and oxide (Ba-promoted copper chromite ((Ba,Cu)_xCr_yO_z) or Sr-modified lanthanum ferrite (LSF)) electrodes on yttria-stabilized zirconia. The Ni:Cr powder bed was capable of reducing the sensing element response to NO₂, NO, CO, and C₃H₆, but the presence of NO₂ or NO (“NO_x”, at 100 ppm by volume) still interfered with the SO₂ response of the Pt–(Ba,Cu)_xCr_yO_z sensing element at 600 °C, causing approximately a 7 mV (20%) reduction in the response to 120 ppm SO₂ and a response equivalent to about 20 ppm SO₂ in the absence of SO₂. The Pt–LSF sensing element, operated at 750 °C, did not suffer from this NO_x interference but at the cost of a reduced SO₂ response magnitude (120 ppm SO₂ yielded 10 mV, in contrast to 30 mV for the Pt-(Ba,Cu)_xCr_yO_z sensing element). The powder bed and Pt–LSF sensing element were operated continuously over approximately 350 h, and the response to SO₂ drifted downward by about 7%, with most of this change occurring during the initial 100 h of operation.     

Urinary proteomic analysis of chronic allograft nephropathy

The pathogenesis of progressive renal allograft injury, which is termed chronic allograft nephropathy (CAN), remains obscure and is currently defined by histology. Prospective protocol-biopsy trials have demonstrated that clinical and standard laboratory tests are insufficiently sensitive indicators of the development and progression of CAN. The study aim was to determine if CAN could be characterized by urinary proteomic data and identify the proteins associated with disease. The urinary proteome of 75 renal transplant recipients and 20 healthy volunteers was analyzed using surface enhanced laser desorption and ionization MS. Patients could be classified into subgroups with normal histology and Banff CAN grades 2-3 with a sensitivity of 86% and a specificity of 92% by applying the classification algorithm Adaboost to urinary proteomic data. Several urinary proteins associated with advanced CAN were identified including α1-microglobulin, β2-microglobulin, prealbumin, and endorepellin, the antiangiogenic C-terminal fragment of perlecan. Increased urinary endorepellin was confirmed by ELISA and increased tissue expression of the endorepellin/perlecan ratio by immunofluoresence analysis of renal biopsies. In conclusion, analysis of urinary proteomic data has further characterized the more severe CAN grades and identified urinary endorepellin, as a potential biomarker of advanced CAN.     

Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

Although recent years have seen significant advances in the spatial resolution possible in the transmission electron microscope (TEM), the temporal resolution of most microscopes is limited to video rate at best. This lack of temporal resolution means that our understanding of dynamic processes in materials is extremely limited. High temporal resolution in the TEM can be achieved, however, by replacing the normal thermionic or field emission source with a photoemission source. In this case the temporal resolution is limited only by the ability to create a short pulse of photoexcited electrons in the source, and this can be as short as a few femtoseconds. The operation of the photo-emission source and the control of the subsequent pulse of electrons (containing as many as 5 x 10(7) electrons) create significant challenges for a standard microscope column that is designed to operate with a single electron in the column at any one time. In this paper, the generation and control of electron pulses in the TEM to obtain a temporal resolution <10(-6)s will be described and the effect of the pulse duration and current density on the spatial resolution of the instrument will be examined. The potential of these levels of temporal and spatial resolution for the study of dynamic materials processes will also be discussed.     

Chipping

Networks dominate today’s computing environment and commercial technical protection is lagging behind attack technology. As a result, protection programme success depends more on prudent management decisions than on the selection of technical safeguards. Managing Network Security takes a management view of protection and seeks to reconcile the need for security with the limitations of technology.     

Why everything keeps failing

Networks dominate today's computing landscape and commercial technical protection is lagging behind attack technology. As a result, protection programme success depends more on prudent management decisions than on the selection of technical safeguards. Managing Network Security takes a management view of protection and seeks to reconcile the need for security with the limitations of technology.     

Learning invariance from natural images inspired by observations in the primary visual cortex

The human visual system has the remarkable ability to largely recognize objects invariant of their position, rotation, and scale. A good interpretation of neurobiological findings involves a computational model that simulates signal processing of the visual cortex. In part, this is likely achieved step by step from early to late areas of visual perception. While several algorithms have been proposed for learning feature detectors, only few studies at hand cover the issue of biologically plausible learning of such invariance. In this study, a set of Hebbian learning rules based on calcium dynamics and homeostatic regulations of single neurons is proposed. Their performance is verified within a simple model of the primary visual cortex to learn so-called complex cells, based on a sequence of static images. As a result, the learned complex-cell responses are largely invariant to phase and position.     

Adjustable Voltage and Frequency Polyphase Sine Wave Signal Generator

An adjustable-voltage adjustable-frequency polyphase reversible-phase sequence sine wave signal generator is described. This signal generator develops the reference waveforms, in this case sine waves, that are required in the control circuits of certain types of static dc to ac inverters and ac to ac cycloconverters. Digital and linear integrated circuits together with passive components are used to generrate the output signals. The output frequency is adjustable from 0 to 500 hertz; the output voltage is adjustable from 0 to 20 volts peak-to-peak. The phase sequence is reversible on command. The theory of operation together with steady-state and transient performance data are presented.     

Predictors of Resilience in Maltreated and Nonmaltreated Latino Children.

To date, few studies have sought to investigate the effects of child maltreatment and processes influencing maladaptation and resilience in Latino children. In the current investigation, multiple aspects of functioning, personal resources, and relationship features were examined in school-age maltreated and nonmaltreated Latino children. Maltreated Latino children were found to have fewer areas of resilient functioning. Ego-resiliency and ego-control, as personal resources, and the ability to form a positive relationship with an adult figure outside of the immediate family predicted resilience. However, certain aspects of interpersonal functioning were differentially related to resilience for maltreated and nonmaltreated Latino children. These findings have implications for understanding how resilience can be promoted in maltreated and nonmaltreated Latino children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

News & notes.

Presents information about the Society for the History of Psychology. Members may obtain the latest information on the Division's web site, or subscribe to the electronic mailing list. The column specifically summarizes the History of Psychology sessions at Southeastern Regional meetings. It also reports on the 23rd Annual Conference of the European Society for the History of the Human Sciences, Salzburg, Austria, July 20–24, 2004. The death of a Division member is also announced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)