Verbs Matter: A Tutorial for Determining Verb Difficulty.

Purpose: Research indicates that when teaching grammatical forms to children, the verbs used to model specific grammatical inflections matter. When learning grammatical forms, children have higher performance when they hear many unique verb forms that vary in their frequency and phonological complexity. In this tutorial, we demonstrate a method for identifying and characterizing a large number of verbs based on their frequency and complexity.

Using Computerized Language Analysis to Evaluate Grammatical Skills.

Purpose Conducting in-depth grammatical analyses based on language samples can be time consuming. Developmental Sentence Scoring (DSS) and the Index of Productive Syntax (IPSyn) analyses provide detailed information regarding the grammatical profiles of children and can be conducted using free computer-based software. Here, we provide a tutorial to support clinicians' use of computer-based analyses to aid diagnosis and develop and monitor treatment goals.

Multi-wavelength microflow cytometer using groove-generated sheath flow.

A microflow cytometer was developed that ensheathed the sample (core) fluid on all sides and interrogated each particle in the sample stream at four different wavelengths. Sheathing was achieved by first sandwiching the core fluid with the sheath fluid laterally via fluid focusing. Chevron-shaped groove features fabricated in the top and bottom of the channel directed sheath fluid from the sides to the top and bottom of the channel, completely surrounding the sample stream.

Two simple and rugged designs for creating microfluidic sheath flow.

A simple design capable of 2-dimensional hydrodynamic focusing is proposed and successfully demonstrated. In the past, most microfluidic sheath flow systems have often only confined the sample solution on the sides, leaving the top and bottom of the sample stream in contact with the floor and ceiling of the channel. While relatively simple to build, these designs increase the risk of adsorption of sample components to the top and bottom of the channel.

The good, the bad, and the tiny: a review of microflow cytometry.

Recent developments in microflow cytometry have concentrated on advancing technology in four main areas: (1) focusing the particles to be analyzed in the microfluidic channel, (2) miniaturization of the fluid-handling components, (3) miniaturization of the optics, and (4) integration and applications development. Strategies for focusing particles in a narrow path as they pass through the detection region include the use of focusing fluids, nozzles, and dielectrophoresis. Strategies for optics range from the use of microscope objectives to polymer waveguides or optical fibers embedded on-chip.

Using bioconjugated nanoparticles to monitor E. coli in a flow channel.

A simple and portable flow channel optical detection system combined with bioconjugated luminescent nanoparticles allows the rapid detection of single bacterial cells without sample enrichment. The optical system is designed to have single-molecule-detection capability in a microcapillary flow channel by decreasing the laser excitation probe volume to a few picoliters, which consequently results in a low background. Specific monoclonal antibodies were immobilized on nanoparticles to form nanoparticle-antibody conjugates.

Surface modification of silica nanoparticles to reduce aggregation and nonspecific binding.

In this article, a systematic study of the design and development of surface-modification schemes for silica nanoparticles is presented. The nanoparticle surface design involves an optimum balance of the use of inert and active surface functional groups to achieve minimal nanoparticle aggregation and reduce nanoparticle nonspecific binding. Silica nanoparticles were prepared in a water-in-oil microemulsion and subsequently surface modified via cohydrolysis with tetraethyl orthosilicate (TEOS) and various organosilane reagents.

Outbreak of travel-related pontiac fever among hotel guests illustrating the need for better diagnostic tests.

Background: Pontiac fever (PF), a legionellosis with influenza-like symptoms and high attack rates, is rarely reported. Travel-related outbreaks can elude detection because infected persons are often widely removed geographically from the transmission source before illness onset. Thirty-one persons staying at an Illinois hotel during August 9 to 11, 2002, reported influenza-like symptoms to local health departments within 24 to 48 hours of checkout.

A rapid bioassay for single bacterial cell quantitation using bioconjugated nanoparticles.

The rapid and sensitive determination of pathogenic bacteria is extremely important in biotechnology, medical diagnosis, and the current fight against bioterrorism. Current methods either lack ultrasensitivity or take a long time for analysis. Here, we report a bioconjugated nanoparticle-based bioassay for in situ pathogen quantification down to single bacterium within 20 min.

Optimization of dye-doped silica nanoparticles prepared using a reverse microemulsion method.

Fluorescent labeling based on silica nanoparticles facilitates unique applications in bioanalysis and bioseparation. Dye-doped silica nanoparticles have significant advantages over single-dye labeling in signal amplification, photostability and surface modification for various biological applications. We have studied the formation of tris(2,2'-bipyridyl)dichlororuthenium(II) (Ru(bpy)) dye-doped silica nanoparticles by ammonia-catalyzed hydrolysis of tetraethyl orthosilicate (TEOS) in water-in-oil microemulsion.