Corneal epithelial homeostasis following daily and overnight contact lens wear.

This report reviews and integrates our recent clinical and laboratory findings of the effects of daily (DW)/overnight (EW) contact lens wear on corneal epithelial homeostasis. In a prospective, double-masked human clinical study, three lens types (high and hyper Dk/t soft; hyper Dk/t RGP) were used to assess the effects of daily and overnight lens wear on corneal epithelial thickness, cell surface size, Pseudomonas aeruginosa (PA) binding to exfoliated epithelial cells and exfoliation rates. Concomitantly, we studied in a rabbit model, the effects of overnight lens wear on corneal epithelial surface cell viability (live/dead assay, TUNEL-labeling, Annexin-V staining, Bcl-2 expression), basal cell proliferation and migration patterns. The comprehensive results obtained yield important new insights on both the normal homeostasis of the corneal epithelium and the biological changes induced by contact lens wear.     

Microconsultation and behavior analysis: A method of training psychologists as behavioral consultants.

Reports the experimental evaluation of a training procedure, termed microconsultation, for transmitting a set of interview skills for using behavior modification with teachers. An 8-wk summer workshop for experienced school psychologists was conducted with a randomly selected group of 30 trainees who underwent the experimental training procedure. Posttest measures of interview techniques at the end of 8 wk. And after a 2-mo interval in the trainees' home school districts found significant changes in the predicted direction over control groups receiving videotape exposure and no experimental contact. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variants of Zr3Co and their superconducting critical temperatures

The effect of ternary substitutions in Zr₃Co was studied. Phase stability and T_c were studied in Zr₃Co_1?xNi_x, Zr₃Co_1?x Cu_x and related alloy systems.     

On the Nature and Elimination of Stimulus Artifact in Nerve Signals Evoked and Recorded Using Surface Electrodes

The electrical stimulus pulse and the surface electrodes commonly used to study compound action potentials of peripheral nerves give rise to an artifact consisting of an initial spike and a longer lasting tail which often interferes with the recorded signal. The artifact has four sources: 1) the voltage gradient between the recording electordes caused by stimulus current flowing through the limb, 2) the common-mode voltage of the limb caused by current escaping through the ground electrode, 3) the capacitive coupling between the stimulating and recording leads, and 4) the high-pass filtering characteristics of the recording amplifier. This paper models these sources and presents several methodological rules for minimizing their effects. Also presented are three computer-based methods for subtracting the residual artifact from contaminated records using estimates of the artifact obtained from: 1) subthreshold stimulation, 2) a second recording site remote from the nerve, or 3) stimulation during the refractory period of the nerve.     

Wood Members Strengthened with Mechanically Fastened FRP Strips

The demand for a rapid technique to strengthen existing wood bridge structural elements is evident in military and civilian sectors. An experimental program was undertaken to evaluate the feasibility of increasing the flexural strength of Southern Pine wood members using mechanically fastened fiber-reinforced polymer (FRP) strips. Three control specimens and twelve composite members were fabricated using two FRP material types with varying fastener spacing and tested to failure. The experimental results show that the proposed strengthening technique induced a gradual failure of the composite members and increased ultimate moment, initial stiffness, and ductility over that found for the control specimens. Increased fastener spacing decreased member ultimate moment, initial stiffness, and ductility ratio. The moisture content of the wood material greatly affected the ductility ratio of the wood members.     

Synthesis and characterization of PVP-coated large core iron oxide nanoparticles as an MRI contrast agent

The purpose of this study was to synthesize biocompatible polyvinylpyrrolidone (PVP)-coated iron oxide (PVP-IO) nanoparticles and to evaluate their efficacy as a magnetic resonance imaging (MRI) contrast agent. The PVP-IO nanoparticles were synthesized by a thermal decomposition method and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and a superconducting quantum interface device (SQUID). The core size of the particles is about 8-10 nm and the overall size is around 20-30 nm. The measured r(2) (reciprocal of T(2) relaxation time) and r2? (reciprocal of T2? relaxation time) are 141.2 and 338.1 (s mM)(-1), respectively. The particles are highly soluble and stable in various buffers and in serum. The macrophage uptake of PVP-IO is comparable to that of Feridex as measured by a Prussian blue iron stain and phantom study. The signal intensity of a rabbit liver was effectively reduced after intravenous administration of PVP-IO. Therefore PVP-IO nanoparticles are potentially useful for T(2)-weighted MR imaging.     

巧用示波器的计算功能分析热插拔电路

尽管数字示波器是电路实验室中最常见的仪器,但有些功能可能并不为人所熟知,数字示波器的计算功能就是其中之一。其实利用数字示波器的计算功能可以简化对热插拔和负载切换电路的分析。本篇应用笔记将介绍如何利用示波器获取MAX5976热插拔电路中MOSFET功耗和负载电容的精确值。     

Human posture simulation to assess cumulative spinal load due to manual lifting. Part I: methods

The estimation of cumulative spinal load (CSL) resulting from exposure to manual materials handling (MMH) may provide a sensitive method for assessing the risk of highly varying exposures. This article reports on a CSL method that involves human posture simulation of workers from videotape in order to assess spinal load exposures due to MMH. The proposed method appears to be sensitive to different durations of exposure, easy to use and useful for assessing jobs with a high degree of variability in task characteristics between lifts. Although the method remains to be validated, it appears to be a useful addition to the range of tools available for assessing manual lifting exposures in worksite-based epidemiologic studies. Ergonomic methods are lacking for assessing highly variable MMH tasks, such as tasks found in warehousing. The existing methods do not include sufficient factors to account for variable exposure patterns or tasks with highly variable task characteristics, such as varying load weights and lift geometries. The CSL assessment method described in this article may provide a way to evaluate these types of tasks in order to assess the overall risk of workers developing work-related musculoskeletal disorders.     

Interactions of Ta2O5 with water vapor at elevated temperatures

Tantalum pentoxide (Ta₂O₅) and its solid solution phases are candidate coatings for components to be used in combustion environments. Thus, it is important to understand the response of Ta₂O₅ to high‐temperature water vapor, a product of combustion. Thermogravimetric methods are used to examine the oxide in reactant streams of controlled water vapor contents at 1250°C‐1450°C. The observed weight loss indicates a reaction of the general form ½ Ta₂O₅(s) + x H₂O(g)=TaO_y(OH)_x(g). Methodical variation in the water vapor pressure suggests the products are a mix of TaO(OH)₃(g) and Ta(OH)₅(g). Evidence of TaO(OH)₃(g) was observed with a sampling mass spectrometer. The measured hydroxide and oxyhyroxide vapor fluxes from Ta₂O₅ are compared with calculated vapor fluxes from SiO₂ and Al₂O₃. Ta₂O₅ exhibits fluxes similar to those from SiO₂ due to gaseous metal hydroxide formation.