Patrick W. C. Ho

Learn More
This article presents preliminary stochastic estimates of the multi-variable human ankle mechanical impedance. We employed Anklebot, a rehabilitation robot for the ankle, to provide torque perturbations. Time histories of the torques in Dorsi-Plantar flexion (DP) and Inversion-Eversion (IE) directions and the associated angles of the ankle were recorded.(More)
This paper reports quantification of multivariable static ankle mechanical impedance when muscles were active. Repetitive measurements using a highly backdrivable therapeutic robot combined with robust function approximation methods enabled reliable characterization of the nonlinear torque-angle relation at the ankle in two coupled degrees of freedom(More)
This article compares stochastic estimates of multi-variable human ankle mechanical impedance when ankle muscles were fully relaxed, actively generating ankle torque or co-contracting antagonistically. We employed Anklebot, a rehabilitation robot for the ankle, to provide torque perturbations. Muscle activation levels were monitored electromyographically(More)
Endothelial nitric oxide synthase (NOS) and neuronal NOS protein increased in proximal tubules of acidotic diabetic rats 3-5 wk after streptozotocin injection. NOS activity (citrulline production) was similar in nondiabetic and diabetic tubules incubated with low glucose (5 mM glucose + 20 mM mannitol); but after 30 min with high glucose (25 mM),(More)
A new global protein digestion and selective peptide extraction strategy for the purpose of monitoring differential protein expression, coined as tagless extraction-retentate chromatography, is introduced. Target protein populations are firstly digested under reduced and alkylated conditions, and resultant peptides selectively extracted via covalent(More)
Overall gastric cancer survival remains poor mainly because there are no reliable methods for identifying highly curable early stage disease. Multi-protein profiling of gastric fluids, obtained from the anatomic site of pathology, could reveal diagnostic proteomic fingerprints. Protein profiles were generated from gastric fluid samples of 19 gastric cancer(More)
Hypothetically either decreased nitric oxide (NO) or increased O(2) could initiate 20-HETE-mediated vasoconstriction associated with hemoglobin-based blood substitutes (HBOC). To test this hypothesis, we infused Tm-Hb, an HBOC with low O(2) affinity, into isoflurane-anesthetized Wistar (W) and Sprague-Dawley (SD) rats after exchanging 20% of their blood(More)
Characterization of multi-variable ankle mechanical impedance is crucial to understanding how the ankle supports lower-extremity function during interaction with the environment. This paper reports quantification of steady-state ankle impedance when muscles were active. Vector field approximation of repetitive measurements of the torque-angle relation in(More)
The mechanical impedance of the human ankle plays a central role in lower-extremity functions requiring physical interaction with the environment. Recent efforts in the design of lower-extremity assistive robots have focused on the sagittal plane; however, the human ankle functions in both sagittal and frontal planes. While prior work has addressed ankle(More)
This article presents the results of two in-vivo studies providing measurements of human static ankle mechanical impedance. Accurate measurements of ankle impedance when muscles were voluntarily activated were obtained using a therapeutic robot, Anklebot, and an electromyographic recording system. Important features of ankle impedance, and their variation(More)