Theoretical and experimental analysis of arrayed imaging reflectometry as a sensitive proteomics technique

Arrayed imaging reflectometry (AIR) is a newly developed label-free optical biosensing technique based on the creation and perturbation of a condition of zero reflectance on a silicon substrate. The antireflective coating is formed by covalently immobilizing arrayed probes on a silicon dioxide film. Probe-target complex formation causes a localized increase in optical thickness and a measurable reflectance change. To evaluate the performance of AIR, we have employed two proteins, intimin and tir, from enteropathogenic E. coli that are critical to the bacterium's mechanism of host infection. Using substrates functionalized with the intimin-binding domain of tir, we demonstrate detection of the extracellular domain of intimin at concentrations as low as 10 pM. Through the use of a diffusion-limited model for the intimin-tir binding interaction at this concentration, we estimate the detected intimin surface concentration to be 0.33 pg/mm2.     

A novel twin-ridge-waveguide optical amplifier switch

A novel twin ridge-waveguide optical amplifier switch is reported. The technique of hydrogen passivation of acceptors has been applied to decrease the current spreading in the region between the ridges. The incorporation of a passive waveguide below the active waveguide leads to the result that using 1.53 μm TE polarized light, through and cross states, each with only 1 dB insertion loss, fiber-to-fiber, can be selected in a device of 360 μm length by varying the currents to each ridge with a total current of 140 mA. A minimum crosstalk of less than -33 dB was achieved when the cross state was selected. This is the first report of a twin ridge-waveguide amplifier switch with such a low-loss, low-polarization sensitivity, and low crosstalk     

An optical tap based on the twin waveguide laser-amplifier withasymmetric flared output waveguides

An optical tap based on the twin waveguide laser-amplifier with asymmetric flared output waveguides is presented. The new optical tap exhibits gain, allows the tap channel gain to be electrically controlled over a dynamic range of 30 dB, without greatly affecting the through channel gain and is optically broadband. The general features of the optical tap can be understood from coupled mode theory     

Dynamic properties of magnetorheological elastomers based on iron sand and natural rubber

In this study, magnetorheological elastomers (MREs) based on iron sand and natural rubber were prepared. The Taguchi method was employed to investigate the effect of a number of factors, namely, the iron sand content, iron sand particle size, and applied magnetic field during curing on the loss tangent (tan δ) and energy dissipated during cyclic loading. Tan δ was measured through dynamic mechanical analysis over a range of frequency (0.01–130 Hz), strain amplitude (0.1–4.5%), and temperature (?100 to 50°C). The energy dissipated was measured with a universal tester under cyclic tensile loading. The data were then statistically analyzed to predict the optimal combination of factors, and finally, experiments were conducted for verification. It was found that the iron sand content had the greatest influence on tan δ when measured over a range of frequency, and the energy dissipated during hysteresis tests. However, none of the factors showed a significant influence on tan δ when measured over a range of strain amplitude. Furthermore, the iron sand content and magnetic field were also found to influence the width of the peak in tan δ as a function of the temperature. The morphological characteristics of the MREs were also examined with scanning electron microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41506.     

Phantoms, ghosts, and such things: A reply to Adams and Peery.

Defends the inclusion of the journal Child Development Monographs in K. C. Mace and H. D. Warner's (1973) and D. Koulack and H. J. Keselman's (see record 1976-24649-001) studies ranking psychology journals in response to G. R. Adams and J. C. Perry's (1980) criticism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrated lossless InGaAsP/InP 1-to-4 optical switch

The fabrication and performance of a 1-to-4 channel optical splitter/combiner are described. The design is based on the integration of a number of twin-guide amplifiers interconnected by active ridge waveguides. Lossless operation is seen fiber-to-fiber for all four ports for TE input light, with a 3-dB bandwidth of 20 nm     

A tubular dielectric elastomer actuator: Fabrication, characterization and active vibration isolation

This contribution reviews the fabrication, characterization and active vibration isolation performance of a core-free rolled tubular dielectric elastomer (DE) actuator, which has been designed and developed by Danfoss PolyPower A/S. PolyPower DE material, PolyPower^TM, is produced in thin sheets of 80 μm thickness with corrugated metallic electrodes on both sides. Tubular actuators are manufactured by rolling the DE sheets in a cylindrical shape. The electromechanical characteristics of such actuators are modeled based on equilibrium pressure equation. The model is validated with experimental measurements from 3 actuators. The dynamic characteristics of three tubular actuators fabricated from the same batch of manufactured DE material are presented and compared to: (a) provide insight into the ability of the fabrication process to produce actuators with similar characteristics and (b) highlight the dominant dynamic characteristics of the core-free tubular actuator. It has been observed that all actuators have similar dynamic characteristics in a frequency range up to 1 kHz. A tubular actuator is then used to provide active vibration isolation (AVI) of a 250 g mass subject to shaker generated ‘ground vibration’. An adaptive feedforward control approach is used to achieve this. The tubular actuator is shown to provide excellent isolation against harmonic vibratory disturbances with attenuation of the resulting 5 and 10 Hz harmonics being 66 and 23 dB, respectively. AVI against a narrow band vibratory disturbance with frequency content 2–8 Hz, produced an attenuation of 20 dB across the frequency band.     

Photoenhanced toxicity of weathered Alaska North Slope crude oil to the calanoid copepods Calanus marshallae and Metridia okhotensis

This study investigated the synergistic toxicity of aqueous polyaromatic compounds (PAC) dissolved from crude oil and ultraviolet radiation (UV) in natural sunlight to the calanoid copepods Calanus marshallae and Metridia okhotensis. These copepods were first exposed to low doses (approximately 2 microg of total PAC/L) of the water-soluble fraction of weathered Alaska North Slope crude oil for 24 h and subsequently to low or high levels of natural sunlight. Responses included mortality, impairment of swimming ability, and discoloration of lipid sacs. There was 80-100% mortality and morbidity of C. marshallae exposed to UV and oil as compared to less than 10% effect in oil-only or UV-only treatments. In M. okhotensis, 100% mortality occurred in the UV and oil treatment, 43% mortality and 27% morbidity in the UV-only treatment, and less than 5% effect in the oil-only treatment. Bioaccumulation factors were approximately 8000 for C. marshallae and approximately 2000 for M. okhotensis. The interaction of the effect of PAC and UV radiation was highly significant (P < 0.005) in both experiments.     

Matching of chronic hospitalized patient groups: Empirical failure of a methodologically "sound" procedure.

Results of 2 experiments with a total of 386 patients show that Ss matched on age, sex, length of hospitalization, and demographic factors obtained markedly different scores on ward behavior scales and a battery of tests (e.g., the WAIS). Results suggest that matching on demographic variables does not ensure similarity on other criteria. (PsycINFO Database Record (c) 2010 APA, all rights reserved)