Feasibility of simultaneous high-resolution anatomical and quantitative magnetic resonance imaging of sciatic nerves in patients with Charcot-Marie-Tooth type 1A (CMT1A) at 7T.

INTRODUCTION/AIMS: Magnetic resonance imaging (MRI) of peripheral nerves can provide image-based anatomical information and quantitative measurement. The aim of this pilot study was to investigate the feasibility of high-resolution anatomical and quantitative MRI assessment of sciatic nerve fascicles in patients with Charcot-Marie-Tooth (CMT) 1A using 7T field strength. METHODS: Six patients with CMT1A underwent imaging on a high-gradient 7T MRI scanner using a 28-channel knee coil. Two high-resolution axial images were simultaneously acquired using a quantitative double-echo in steady-state (DESS) sequence. By comparing the two DESS echoes, T2 and apparent diffusion coefficient (ADC) maps were calculated. The cross-sectional areas and mean T2 and ADC were measured in individual fascicles of the tibial and fibular (peroneal) portions of the sciatic nerve at its bifurcation and 10 mm distally. Disease severity was measured using Charcot-Marie-Tooth Examination Score (CMTES) version 2 and compared to imaging findings. RESULTS: We demonstrated the feasibility of 7T MRI of the proximal sciatic nerve in patients with CMT1A. Using the higher field, it was possible to measure individual bundles in the tibial and fibular divisions of the sciatic nerve. There was no apparent correlation between diffusion measures and disease severity in this small cohort. DISCUSSION: This pilot study indicated that high-resolution MRI that allows for combined anatomical and quantitative imaging in one scan is feasible at 7T field strengths and can be used to investigate the microstructure of individual nerve fascicles.

Apertureless cantilever-free pen arrays for scanning photochemical printing.

A novel, apertureless, cantilever-free pen array can be used for dual scanning photochemical and molecular printing. Serial writing with light is enabled by combining self-focusing pyramidal pens with an opaque backing between pens. The elastomeric pens also afford force-tuned illumination and simultaneous delivery of materials and optical energy. These attributes make the technique a promising candidate for maskless high-resolution photopatterning and combinatorial chemistry.

Development of reactive artificial liner using recycled materials. 1. Mechanical properties and chemical compatibility.

There have been several studies showing that volatile organic compounds (VOCs) can diffuse a geomembrane within days and migrate to groundwater and the surrounding environment. To ease the concern of potential pollution of the surrounding environment, an alternative artificial liner consisting of recycled materials is proposed. This composite liner consisted of recycled crumb rubber, organo-clay, silica fume, and epoxy binder. Dimethyl sulfoxide, an environmentally-friendly solvent recycled from paper pulp, was used as a plasticizer. The objective of this study was to determine the best combination of ingredients used at the initial stage and to develop artificial liners suitable for containing VOCs in leachate by comparing various physical properties. A series of screening tests including bending, tearing and elongating was performed to determine the most suitable mixture ratios. Then, more intensive tests were performed with the specimens that had the best physical properties. The new artificial liner demonstrated satisfactory mechanical properties with the minimum elongation and maximum strength after 40 years. Both artificial liners and high-density polyethylene (HDPE) specimens had ~136 kg cm(-2) after 4 months of thermal stress while the artificial liner had 40% less elongation at break than HDPE. The artificial liner's fully developed strength was about ten times stronger than HDPE. This new type of composite material that can be applied on site may provide a new perspective in liner design and alleviate the issue of potential groundwater pollution caused by landfill leachate and highly mobile VOCs which is a matter of much concern.

Mechanically-compliant intracortical implants reduce the neuroinflammatory response.

OBJECTIVE: The mechanisms underlying intracortical microelectrode encapsulation and failure are not well understood. A leading hypothesis implicates the role of the mechanical mismatch between rigid implant materials and the much softer brain tissue. Previous work has established the benefits of compliant materials on reducing early neuroinflammatory events. However, recent studies established late onset of a disease-like neurodegenerative state. APPROACH: In this study, we implanted mechanically-adaptive materials, which are initially rigid but become compliant after implantation, to investigate the long-term chronic neuroinflammatory response to compliant intracortical microelectrodes. MAIN RESULTS: Three days after implantation, during the acute healing phase of the response, the tissue response to the compliant implants was statistically similar to that of chemically matched stiff implants with much higher rigidity. However, at two, eight, and sixteen weeks post-implantation in the rat cortex, the compliant implants demonstrated a significantly reduced neuroinflammatory response when compared to stiff reference materials. Chronically implanted compliant materials also exhibited a more stable blood-brain barrier than the stiff reference materials. SIGNIFICANCE: Overall, the data show strikingly that mechanically-compliant intracortical implants can reduce the neuroinflammatory response in comparison to stiffer systems.