Behavior of compounds leached from tire tread particles under simulated sunlight exposure.

Tire tread particles are microplastics (< 5 mm) and leach organic chemicals into aquatic environments. It is important to understand the behavior of tire wear compounds in sunlight-exposed waters in terms of their persistence, removal, and transformation. Therefore, we conducted photolysis experiments with leachates from laboratory-generated tire tread particles (TTP) over 72 h in a solar simulator to evaluate the behavior of leached compounds and fluorescent components over time.

Life after a fiery death: Fire and plant biomass loading affect dissolved organic matter in experimental ponds.

Drier and hotter conditions linked with anthropogenic climate change can increase wildfire frequency and severity, influencing terrestrial and aquatic carbon cycles at broad spatial and temporal scales. The impacts of wildfire are complex and dependent on several factors that may increase terrestrial deposition and the influx of dissolved organic matter (DOM) from plants into nearby aquatic systems, resulting in the darkening of water color. We tested the effects of plant biomass quantity and its interaction with fire (burned vs.

Micron-size tire tread particles leach organic compounds at higher rates than centimeter-size particles: Compound identification and profile comparison.

Tire tread particles (TTP) are environmentally prevalent microplastics and generate toxic aqueous leachate. We determined the total carbon and nitrogen leachate concentrations and chemical profiles from micron (∼32 μm) and centimeter (∼1 cm) TTP leachate over 12 days. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were used to measure the concentration of leached compounds.

High-frequency ultrasonic imaging of growth and development in manufactured engineered oral mucosal tissue surfaces.

This study uses high-resolution ultrasound to examine the growth and development of engineered oral mucosal tissues manufactured under aseptic conditions. The specimens are a commercially available natural tissue scaffold, AlloDerm, and oral keratinocytes seeded onto AlloDerm to form an ex vivo-produced oral mucosal equivalent (EVPOME) suitable for intra-oral grafting. The seeded cells produce a keratinized protective upper layer that smooths out any remaining surface irregularities on the underlying AlloDerm.

Measurement of corneal elasticity with an acoustic radiation force elasticity microscope.

To investigate the role of collagen structure in corneal biomechanics, measurement of localized corneal elasticity with minimal destruction to the tissue is necessary. We adopted the recently developed acoustic radiation force elastic microscopy (ARFEM) technique to measure localize biomechanical properties of the human cornea. In ARFEM, a low-frequency, high-intensity acoustic force is used to displace a femtosecond laser-generated microbubble, while high-frequency, low-intensity ultrasound is used to monitor the position of the microbubble within the cornea.

Using an ultrasound elasticity microscope to map three-dimensional strain in a porcine cornea.

An ultrasound elasticity microscope was used to map 3-D strain volume in an ex vivo porcine cornea to illustrate its ability to measure the mechanical properties of this tissue. Mechanical properties of the cornea play an important role in its function and, therefore, also in ophthalmic diseases such as kerataconus and corneal ectasia. The ultrasound elasticity microscope combines a tightly focused high-frequency transducer with confocal scanning to produce high-quality speckle over the entire volume of tissue.

Characterizing morphology and nonlinear elastic properties of normal and thermally stressed engineered oral mucosal tissues using scanning acoustic microscopy.

This study examines the use of high-resolution ultrasound to monitor changes in the morphology and nonlinear elastic properties of engineered oral mucosal tissues under normal and thermally stressed culture conditions. Nonlinear elastic properties were determined by first developing strain maps from acoustic ultrasound, followed by fitting of nonlinear stress-strain data to a 1-term Ogden model. Testing examined a clinically developed ex vivo produced oral mucosa equivalent (EVPOME).

Three-dimensional mapping of strain in ex vivo porcine cornea with an ultrasound elasticity microscope.

High frequency strain mapping of a porcine cornea was produced by three-dimensional speckle tracking of a three-dimensional confocally merged ultrasonic data set. Previous two-dimensional elasticity imaging was limited by speckle moving in the non-imaged dimension. This study used an ultrasonic transducer (53 MHz center frequency, 31 MHz bandwidth, 1.

Non-linear stress-strain measurements of ex vivo produced oral mucosal equivalent (EVPOME) compared to normal oral mucosal and skin tissue.

Stress-strain curves of oral mucosal tissues were measured using direct mechanical testing. Measurements were conducted on both natural oral mucosal tissues and engineered devices, specifically a clinically developed ex vivo produced oral mucosal equivalent (EVPOME). As seeded cells proliferate on EVPOME devices, they produce a keratinized protective upper layer which fills in surface irregularities.

Comparison of scanning acoustic microscopy and histology images in characterizing surface irregularities among engineered human oral mucosal tissues.

Acoustic microscopy was used to monitor an ex vivo produced oral mucosal equivalent (EVPOME) developed on acellular cadaveric dermis (AlloDerm®). As seeded cells adhered and grew, they filled in and smoothed out the surface irregularities, followed by the production of a keratinized protective outermost layer. If noninvasive in vitro ultrasonic monitoring of these cellular changes could be developed, then tissue cultivation could be adjusted in-process to account for biologic variations in the development of these stratified cell layers.

Acoustic microscopy analyses to determine good vs. failed tissue engineered oral mucosa under normal or thermally stressed culture conditions.

This study uses scanning acoustic microscopy (SAM) ultrasonic profilometry to determine acceptable vs. failed tissue engineered oral mucosa. Specifically, ex vivo-produced oral mucosal equivalents (EVPOMEs) under normal or thermally stressed culture conditions were scanned with the SAM operator blinded to the culture conditions.

Mapping elasticity in human lenses using bubble-based acoustic radiation force.

This study uses acoustic radiation pressure to displace a femtosecond laser-produced bubble in human lens tissue. Bubble displacement is monitored with low-amplitude, high-resolution ultrasound. Displacements are compensated by bubble size determined from ultrasonic backscatter.

Bubble-based acoustic radiation force using chirp insonation to reduce standing wave effects.

Bubble-based acoustic radiation force can measure local viscoelastic properties of tissue. High intensity acoustic waves applied to laser-generated bubbles induce displacements inversely proportional to local Young's modulus. In certain instances, long pulse durations are desirable but are susceptible to standing wave artifacts, which corrupt displacement measurements.

Mapping age-related elasticity changes in porcine lenses using bubble-based acoustic radiation force.

Bubble-based acoustic radiation force aims to measure highly localized tissue viscoelastic properties. In the current investigation, acoustic radiation force was applied to laser-induced bubbles to measure age-related changes in the spatial distribution of elastic properties within in vitro porcine lenses. A potential in vivo technique to map lens elasticity is crucial to understanding the onset of presbyopia and develop new treatment options.

Acoustic detection of controlled laser-induced microbubble creation in gelatin.

A high-frequency (85 MHz) acoustic technique is used to identify system parameters for controlled laser-induced microbubble creation inside tissue-mimicking, gelatin phantoms. Microbubbles are generated at the focus of an ultrafast 793-nm laser source and simultaneously monitored through ultrasonic pulse-echo recordings. Displayed in wavefield form, these recordings illustrate microbubble creation, and integrated backscatter plots provide specifics about microbubble characteristics and dissolution behavior.

Bubble-based acoustic radiation force elasticity imaging.

Acoustic radiation force is applied to bubbles generated by laser-induced optical breakdown (LIOB) to study viscoelastic properties of the surrounding medium. In this investigation, femtosecond laser pulses are focused in the volume of gelatin phantoms of different concentrations to form bubbles. A two-element confocal ultrasonic transducer generates acoustic radiation force on individual bubbles while monitoring their displacement within a viscoelastic medium.

Trapping cavitation bubbles with a self-focused laser beam.

We observed that laser-induced cavitation bubbles in water can be trapped in a self-focused laser beam. Both optical imaging and acoustic detection have been utilized to confirm bubble trapping. Transverse and longitudinal trapping forces were measured to be as large as 87 and 11 pN, respectively.

Strain imaging of corneal tissue with an ultrasound elasticity microscope.

Purpose: We hypothesize that high-resolution elasticity measurements can guide corrective refractive surgery of the cornea. Elasticity measurements would improve surgical outcomes by adding biomechanical information not used in existing clinical nomograms. As an initial investigation, we determined the usefulness and evaluated the ability of our ultrasound elasticity microscope by measuring strain ex vivo in an intact porcine eye globe.

Pulsatile expansion therapy for orbital enlargement.

Experimental and clinical investigations have documented the modulatory role of the globe in the development of the orbit. In cases of absence or early loss of the globe, severe hypoplasia of the orbit and midface has been reported by several authors. Statical conformers and orbital osteotomies have been used to correct the resulting facial asymmetry.

Familial aggregates in obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) was diagnosed in157 subjects based on clinical symptoms, physical evaluation, cephalometric x-ray films, and polysomnography. These index cases identified 844 living first-degree relatives. Mailings were sent to 792 (94%).