Hybrid Control Interface of a Semi-soft Assistive Glove for People with Spinal Cord Injuries.

Active assistive devices have been designed to augment the hand grasping capabilities of individuals with spinal cord injuries (SCI). An intuitive bio-signal of wrist extension has been utilized in the device control, which imitates the passive grasping effect of tenodesis. However, controlling these devices in this manner limits the wrist joint motion while grasping. This paper presents a novel hybrid control interface and corresponding algorithms (i.e., a hybrid control method) of the Semi-soft Assistive Glove (SAG) developed for individuals with C6/C7-SCI. The secondary control interface is implemented to enable/disable the grasp trigger signal generated by the primary interface detecting the wrist extension. A simulation study reveals that the hybrid control method can facilitate grasping situations faced in daily activities. Empirical results with three healthy subjects suggest that the proposed method can assist the user to reach and grasp objects with the SAG naturally.

Development of a native Escherichia coli induction system for ionic liquid tolerance.

The ability to solubilize lignocellulose makes certain ionic liquids (ILs) very effective reagents for pretreating biomass prior to its saccharification for biofuel fermentation. However, residual IL in the aqueous sugar solution can inhibit the growth and function of biofuel-producing microorganisms. In E. coli this toxicity can be partially overcome by the heterologous expression of an IL efflux pump encoded by eilA from Enterobacter lignolyticus. In the present work, we used microarray analysis to identify native E. coli IL-inducible promoters and develop control systems for regulating eilA gene expression. Three candidate promoters, PmarR', PydfO', and PydfA', were selected and compared to the IPTG-inducible PlacUV5 system for controlling expression of eilA. The PydfA' and PmarR' based systems are as effective as PlacUV5 in their ability to rescue E. coli from typically toxic levels of IL, thereby eliminating the need to use an IPTG-based system for such tolerance engineering. We present a mechanistic model indicating that inducible control systems reduce target gene expression when IL levels are low. Selected-reaction monitoring mass spectrometry analysis revealed that at high IL concentrations EilA protein levels were significantly elevated under the control of PydfA' and PmarR' in comparison to the other promoters. Further, in a pooled culture competition designed to determine fitness, the strain containing pPmarR'-eilA outcompeted strains with other promoter constructs, most significantly at IL concentrations above 150 mM. These results indicate that native promoters such as PmarR' can provide effective systems for regulating the expression of heterologous genes in host engineering and simplify the development of industrially useful strains.