Spinal cord injuries (SCI), unlike other injuries, often exhibit limited recovery. Patients with SCI often face major detriments to quality of life and health due to impaired motor control, sensation, and homeostatic regulation. In SCI patient surveys, regaining hand function is consistently among the highest priorities. We use a rat model of cervical SCI to develop therapies that restore motor function for reaching and grasping. We have shown that rats that receive targeted, activity-dependent spinal stimulation (TADSS) at a single spinal site for forelimb reaching exhibited enhanced recovery compared to physical retraining or open-loop electrical stimulation. Spinal stimulation is delivered to the injured forelimb of the rat when muscular activity, during reaching and grasping, is displayed. We used the single pellet grasping (SPG) task to assess forelimb function. Our hypothesis was that modifying the TADSS protocol to include stimulation of multiple motor pathways (MTADSS) for reaching and grasping will produce greater recovery than single site TADSS. In the current project, male and female Long-Evans rats were injured with a unilateral C4-C5 spinal hemi-contusion which primarily impairs the dominant forelimb. Four weeks after injury, the animals were implanted with spinal stimulation wires and wires for recording the muscle activity of the impaired forelimb. MTADSS and unstimulated control rats, underwent fourteen weeks of daily SPG, lever pull, which measures pull strength, and two other functional assessments, which will be reported elsewhere. MTADSS rats show recovery in SPG and a principal component analysis of lever pull showed that mean peak force (MPF), explains 84% of the variance between control rats and therapy rats at week 7 of therapy. The increased MPF among MTADSS rats suggests increased muscle recovery due to therapy. Taken together, MTADSS therapy seems to promote recovery in multiple measures of forelimb function compared to physical retraining alone.

We probe the crystal structure and the proton conductivity of magnesium hydrogen phosphate trihydrate MgHPO₄·3H₂O, also known as newberyite. Newberyite is used as an ingredient in pigments, plastics, and anticorrosive paints, and as an alkaline phosphate it has potential for use in proton conduction. The structural transition and the proton diffusive motion as a function of temperature from 20K to 383K have been studied using X-ray crystallography, quasi-elastic neutron scattering (QENS) spectroscopy and atomic force microscopy (AFM), collected from the National Institute of Standards and Technology (NIST) and the Center for Nanophase Materials Sciences (CNMS) at Oak Ridge National Laboratory (ORNL). We confirm that newberyite undergoes a crystalline-to-amorphous dehydration phase transition at low temperatures, which is unusual in other phosphate materials. We compare our analysis with previous crystallographic surveys.

SrHPO₄ is of interest as a candidate material for use in proton-exchange membranes, as a startup material for ceramic fuel-cells, and as a catalyst, but until now its proton mobility had not been studied by quasi-elastic neutron scattering (QENS). QENS analysis of a material provides an understanding of its usefulness for these applications. It displays the behavior of proton diffusion processes in a sample, and the stability of such processes at a wide range of temperatures is crucial to the success of a candidate material. A QENS experiment was performed at the National Institute of Standards and Technology (NIST) on SrHPO₄ powder from 20K to 523K using a Disk Chopper Spectrometer (DCS). Data analysis was then conducted to gain insight into the properties of the sample at each of these temperatures. The data was modeled with background, delta, and Lorentzian functions, as parameters of these models constrain the physical behavior of protons in SrHPO₄. These results were compared with a QENS analysis of Monetite (CaHPO₄) to provide further context to our findings.

More than half of spinal cord injuries (SCI) affect the cervical cord, which can have devastating life-long impairments to hand and arm function. We use a rodent model of cervical spinal contusion to develop activity dependent electrical stimulation therapy for regaining fine motor function after SCI. The Ohio State Injury Device uses an electromagnetic impounder to compress the spinal cord with a 2.5 mm probe and control variables that can affect the severity of the injury, most importantly displacement (i.e. how much the cord is compressed during injury). However, here we show that injury severity varies more than controlling for displacement can account for. We have also investigated the effect of surgeon on injury severity, which appears to have a small influence on injury severity. Upon further analysis, we have found that given similar probe displacements, male rats exhibit greater functional deficits after injury than female rats. Physiological differences such as size and hormone levels vary between males and females and may impact severity of motor function deficits. We hypothesize estrogen levels may influence injury severity. Previous studies have shown administering estrogen to a rat after SCI is neuroprotective and to decrease apoptotic activity in the spinal cord. In our ongoing studies, we will monitor the stage of the estrous cycle (a proxy for measuring estrogen and other hormones) in female rats prior to injury. Investigating the effects of estrogen on SCI helps us develop and understand injury models and motor function after SCI. A more sophisticated injury model may help us develop more effective treatments for SCI. Ultimately, results may help bring novel therapies closer to clinical use.

As the world's climate situation becomes more dire, the need for a clean, renewable energy source becomes more pronounced. Proton conductor fuel cells (PCFCs) use the chemical energy of hydrogen fuel efficiently and cleanly to produce electricity with zero-emission. A proton conductor electrolyte is the heart of the fuel cell operation. Alkaline phosphates such as SrHPO₄ are an attractive class of compounds for potential electrolyte materials in proton conducting fuel cells; understanding the crystal structure as function of temperature, the way crystal defects affect structure, the proton conductivity, and resultant properties is of great importance to the advancement of both science and industry. To this end, we are interested in making progress in the science of phosphates as potential proton conductors by studying the structure of SrHPO₄ and other aliovalent (Ca, Ba) phosphate materials by neutron powder diffraction (NPD). Studying the phosphate family allows us to characterize the correlation between the aliovalent alkaline-earth oxide local structures and the measured dynamics properties. An advanced comprehension study of the change in structure of SrHPO₄ as a function of temperature will provide clues to the relationship between structure and the dynamics of proton conduction. In an effort to better understand the structural properties of SrHPO₄ as a function of temperature, NPD data was collected in temperatures ranging from 6K to 300K. X-ray Diffraction(XRD) was performed at 150K and 300K. Surface topography was studied via Scanning Electron Microscopy(SEM) and Atomic Force Microscopy (AFM), collected at Oak Ridge National Laboratory (ORNL). The NPD data was analyzed using the Rietveld Method in conjunction with the FullProf software tool, and we will compare the results with those of CaHPO₄ and BaHPO₄ in order to better understand the relationship between the crystal structure and the proton conduction dynamics of these materials.