Design and Evaluation of Pediatric Gait Rehabilitation Robots

Gait therapy methodologies were studied and analyzed for their potential for pediatric patients. Using data from heel, metatarsal, and toe trajectories, a nominal gait trajectory was determined using Fourier transforms for each foot point. These average trajectories were used as a basis of evaluating each gait therapy mechanism. An existing gait therapy device (called ICARE) previously designed by researchers, including engineers at the University of Nebraska-Lincoln, was redesigned to accommodate pediatric patients. Unlike many existing designs, the pediatric ICARE did not over- or under-constrain the patient’s leg, allowing for repeated, comfortable, easily-adjusted gait motions. This design was assessed under clinical testing and deemed to be acceptable. A gait rehabilitation device was designed to interface with both pediatric and adult patients and more closely replicate the gait-like metatarsal trajectory compared to an elliptical machine. To accomplish this task, the nominal gait path was adjusted to accommodate for rotation about the toe, which generated a new trajectory that was tangent to itself at the midpoint of the stride. Using knowledge of the bio-mechanics of the foot, the gait path was analyzed for its applicability to the general population. Several trajectory-replication methods were evaluated, and the crank-slider mechanism was chosen for its superior performance and ability to mimic the gait path adequately. Adjustments were made to the gait path to further optimize its realization through the crank-slider mechanism. Two prototypes were constructed according to the slider-crank mechanism to replicate the gait path identified. The first prototype, while more accurately tracing the gait path, showed difficulty in power transmission and excessive cam forces. This prototype was ultimately rejected. The second prototype was significantly more robust. However, it lacked several key aspects of the original design that were important to matching the design goals. Ultimately, the second prototype was recommended for further work in gait-replication research. Advisor: Carl A. Nelso

Design and Evaluation of Pediatric Gait Rehabilitation Robots

Gait therapy methodologies were studied and analyzed for their potential for pediatric patients. Using data from heel, metatarsal, and toe trajectories, a nominal gait trajectory was determined using Fourier transforms for each foot point. These average trajectories were used as a basis of evaluating each gait therapy mechanism. An existing gait therapy device (called ICARE) previously designed by researchers, including engineers at the University of Nebraska-Lincoln, was redesigned to accommodate pediatric patients. Unlike many existing designs, the pediatric ICARE did not over- or under-constrain the patient’s leg, allowing for repeated, comfortable, easily-adjusted gait motions. This design was assessed under clinical testing and deemed to be acceptable. A gait rehabilitation device was designed to interface with both pediatric and adult patients and more closely replicate the gait-like metatarsal trajectory compared to an elliptical machine. To accomplish this task, the nominal gait path was adjusted to accommodate for rotation about the toe, which generated a new trajectory that was tangent to itself at the midpoint of the stride. Using knowledge of the bio-mechanics of the foot, the gait path was analyzed for its applicability to the general population. Several trajectory-replication methods were evaluated, and the crank-slider mechanism was chosen for its superior performance and ability to mimic the gait path adequately. Adjustments were made to the gait path to further optimize its realization through the crank-slider mechanism. Two prototypes were constructed according to the slider-crank mechanism to replicate the gait path identified. The first prototype, while more accurately tracing the gait path, showed difficulty in power transmission and excessive cam forces. This prototype was ultimately rejected. The second prototype was significantly more robust. However, it lacked several key aspects of the original design that were important to matching the design goals. Ultimately, the second prototype was recommended for further work in gait-replication research. Advisor: Carl A. Nelso

The \u3cem\u3eMeiothermus ruber\u3c/em\u3e Mrub_2572 gene is an ortholog of the \u3cem\u3eEscherichia coli\u3c/em\u3e pyrE b3642 gene and the \u3cem\u3eMeiothermus ruber\u3c/em\u3e Mrub_2071 gene is an ortholog of the \u3cem\u3eEscherichia coli\u3c/em\u3e pyrF b1281 gene

This project is part of the Meiothermus ruber genome analysis project, which uses the bioinformatics tools associated with the Guiding Education through Novel Investigation –Annotation Collaboration Toolkit (GENI-ACT) to predict gene function. We investigated the biological function of the genes Mrub_2572 and Mrub_2071. We predict that Mrub_2572 encodes the enzyme orotate phosphoribosyltransferase (DNA coordinates 2617545..2618096 on the forward strand), which is the 5th step of the UMP biosynthesis pathway (KEGG map number 00240). It catalyzes the conversion of orotate + PRPP to orotidine 5’-phosphate. The E. coli K12 MG1655 ortholog is predicted to be b3642, which has the gene identifier pyrE. We also predict that Mrub_2071 encodes the enzyme orotidine 5\u27-phosphate decarboxylase (DNA coordinates 2109095..2109871 on the forward strand), which is the 6th step of the UMP biosynthesis pathway (KEGG map number 00240). It catalyzes the conversion of orotidine 5’-phosphate to uridine monophosphate (UMP). The E. coli K12 MG1655 ortholog is predicted to be b1281, which has the gene identifier pyrF

Confirmation of the function of Mrub1080 as γ-glutamyl kinase (ProB) in Meiothermus ruber

This project is part of the Meiothermus ruber genome analysis project, which uses wet lab procedures and computational analysis to gather evidence of orthologous genes between Escherichia coli and Meiothermus ruber. In previous work, bioinformatics evidence supported the hypothesis that the gene Mrub1080 was an ortholog of E. coli proB. We investigated the biological function of Meiothermus ruber genes proB and proBA using the complementation assay. However, functional analysis proved inconclusive. For this particular research project, we confirmed that weakly complementing E. coli proB- null strains actually contained the desired M. ruber proB and proBA genes (inserted into a pKt1 expression vector), as opposed to being growth artifacts or bacterial contamination. The proB gene encodes the γ-glutamyl kinase (EC 2.7.2.11), which is the first step of the proline biosynthesis pathway (KEGG map number 00330). The proBA gene encodes the first two enzymes of the proline biosynthesis pathway γ-glutamyl kinase (EC 2.7.2.11) and γ-glutamyl phosphate reductase (EC 1.2.1.41), suggesting they are part of an operon

A field-extrema hysteresis loss model for high-frequency ferrimagnetic materials

We present a new field-extrema hysteresis loss model (FHM) for high-frequency ferrimagnetic materials, along with a parameter identification procedure. The model does not involve solving an ordinary differential equation (ODE) and is asymmetric in that it works well under dc bias conditions. In the proposed model, the loss calculations are based on the extrema values of the fields. The model includes the effects of magnetic saturation as well as frequency effects. The model is comparable in accuracy to the ODE-based Jiles-Atherton model, but retains the convenience and computational efficiency of an empirical model. We demonstrate a procedure to characterize the model parameters using the Jiles-Atherton model. We compare magnetic hysteresis loss calculated by our new model with a full time-domain solution, as well as an empirical model, for a sample high-frequency ferrite. We demonstrate the use of the model, and validate the model, by calculating magnetic loss in an EI core inductor operating as the filter inductor in a buck converter. The model and identification procedure are being endorsed as a useful framework for computing magnetic loss in the context of automated magnetic device design

Biomechanical Foot Guidance Linkage

A gait replication apparatus can include a scalable mechanical mechanism configured to replicate different gaits . The scalable mechanical mechanism can include , for example , a four - bar linkage , a pantograph , a cam / Scotch - yoke mechanism , and so forth . In some embodiments , the mechanical mechanism includes a beam rotating about an axis passing proximate to its center , with a foot pedal slidably coupled with the beam , and a timing chain / belt or cable pulley - pair coupled with the foot pedal and looped about the beam . A method can include decomposing a foot path defined by Cartesian coordinates into polar coordinates , and providing a mechanical support for a foot , where a first mechanism controls an angular position of the mechanical support with respect to a reference frame , and a second mechanism controls a radial distance of the mechanical support from the reference frame

C1,1C^{1,1} regularity for principal-agent problems

We prove the interior $C^{1,1}$ regularity of the indirect utilities which solve a subclass of principal-agent problems originally considered by Figalli, Kim, and McCann. Our approach is based on construction of a suitable comparison function which, essentially, allows one to pinch the solution between parabolas. The original ideas for this proof arise from an earlier, unpublished, result of Caffarelli and Lions for bilinear preferences which we extend here to general quasilinear benefit functions. We give a simple example which shows the $C^{1,1}$ regularity is optimal.Comment: 19 pages, 1 figure; updated based on reviewer's comment to include additional expositio