Monitoring levodopa oxidation and reduction reactions using surface plasmon resonance on a nanohole array electrode.

The traditional method of monitoring the oxidation and reduction of biomedical materials usually relies on electrochemical (EC) measurement techniques. Here, we demonstrate a surface plasmon resonance (SPR) method to monitor the oxidation process. Using levodopa L-dopa as the target analyte, a nanohole sensing plate is embedded in the EC electrode to enhance the oxidation signal and generate SPR. Cyclic voltammetry (CV) measurement was first conducted to understand the baseline of EC response of L-Dopa. Then, the redox reactions were simultaneously monitored through SPR measurements during the CV voltage scan. The results showed that the limit of detection using traditional CV reached 1.47 µM while using EC-SPR, the limit of detection improved to 1.23 µM. Most importantly, we found a strong correlation between CV current profiles and the SPR reflection spectra. Our results facilitate detecting electrochemical reactions using an optical probing method.

Design and evaluation of an independent 4-week, exosuit-assisted, post-stroke community walking program.

Chronic impairment in the paretic ankle following stroke often requires that individuals use compensatory patterns such as asymmetric propulsion to achieve effective walking speeds needed for community engagement. Ankle exosuit assistance can provide ankle biomechanical benefit in the lab, but such environments inherently limit the amount of practice available. Community walking studies without exosuits can provide massed practice and benefit walking speed but are limited in their ability to assist proper mechanics. In this study, we combined the positive aspects of community training with those of exosuit assistance. We developed and evaluated a community Robotic Exosuit Augmented Locomotion (cREAL) program. Four participants in the chronic stage of stroke independently used our community ankle exosuit for walking in the community 3-5 days/week for 4 weeks. We performed lab evaluations before and after the 4-week program. Two participants significantly improved their unassisted paretic propulsion by an average of 27% after the program and walked on average 4001 steps/day more in the week following the program. Despite the small number of participants, this study provides preliminary evidence for the potential of exosuits to augment gait training and rehabilitation in the community.

GaN Vertical Transistors with Staircase Channels for High-Voltage Applications.

In this study, we propose and simulate the design of a non-regrowth staircase channel GaN vertical trench transistor, demonstrating an exceptional threshold and breakdown characteristic for high power and high frequency applications. The unique staircase design provides a variable capacitance through the gate-dielectric-semiconductor interface, which results in a high breakdown voltage of 1.52 kV and maintains a channel on-resistance of 2.61 mΩ∙cm2. Because of the variable length and doping profile in the channel region, this model offers greater flexibility to meet a wide range of device application requirements.

A Portable Passive Rehabilitation Robot for Upper-Extremity Functional Resistance Training.

OBJECTIVE: Loss of arm function is common in individuals with neurological damage, such as stroke or cerebral palsy. Robotic devices that address muscle strength deficits in a task-specific manner can assist in the recovery of arm function; however, current devices are typically large, bulky, and expensive to be routinely used in the clinic or at home. This study sought to address this issue by developing a portable planar passive rehabilitation robot, PaRRo. METHODS: We designed PaRRo with a mechanical layout that incorporated kinematic redundancies to generate forces that directly oppose the user's movement. Cost-efficient eddy current brakes were used to provide scalable resistances. The lengths of the robot's linkages were optimized to have a reasonably large workspace for human planar reaching. We then performed theoretical analysis of the robot's resistive force generating capacity and steerable workspace using MATLAB simulations. We also validated the device by having a subject move the end-effector along different paths at a set velocity using a metronome while simultaneously collecting surface electromyography (EMG) and end-effector forces felt by the user. RESULTS: Results from simulation experiments indicated that the robot was capable of producing sufficient end-effector forces for functional resistance training. We also found the endpoint forces from the user were similar to the theoretical forces expected at any direction of motion. EMG results indicated that the device was capable of providing adjustable resistances based on subjects' ability levels, as the muscle activation levels scaled with increasing magnet exposures. CONCLUSION: These results indicate that PaRRo is a feasible approach to provide functional resistance training to the muscles along the upper extremity. SIGNIFICANCE: The proposed robotic device could provide a technological breakthrough that will make rehabilitation robots accessible for small outpatient rehabilitation centers and in-home therapy.

Correction to: A Semi-passive Planar Manipulandum for Upper-Extremity Rehabilitation.

Authors would like to correct their acknowledgments. Correct acknowledgments appear here.

A Semi-passive Planar Manipulandum for Upper-Extremity Rehabilitation.

Robotic rehabilitation is a promising approach to treat individuals with neurological or orthopedic disorders. However, despite significant advancements in the field of rehabilitation robotics, this technology has found limited traction in clinical practice. A key reason for this issue is that most robots are expensive, bulky, and not scalable for in-home rehabilitation. Here, we introduce a semi-passive rehabilitation robot (SepaRRo) that uses controllable passive actuators (i.e., brakes) to provide controllable resistances at the end-effector over a large workspace in a manner that is cost-effective and safe for in-home use. We also validated the device through theoretical analyses, hardware experiments, and human subject experiments. We found that by including kinematic redundancies in the robot's linkages, the device was able to provide controllable resistances to purely resist the movement of the end-effector, or to gently steer (i.e., perturb) its motion away from the intended path. When testing these capabilities on human subjects, we found that many of the upper-extremity muscles could be selectively targeted based on the forcefield prescribed to the user. These results indicate that SepaRRo could serve as a low-cost therapeutic tool for upper-extremity rehabilitation; however, further testing is required to evaluate its therapeutic benefits in patient population.

Improve elderly people's sit-to-stand ability by using new designed additional armrests attaching on the standard walker.

BACKGROUND: More and more elderly problems come to our life and the elderly health care become more important. Elderly people with lower extremities weakness usually use walkers to assist in walking. Although the commercial standard walkers (N-type) can improve elderly people's walking ability, users sometimes take risk of falling when using the standard walkers to perform sit-to-stand (STS). The purpose of this study is to design an additional armrest which can be attached to a standard walker for users performing STS more easily and evaluate it with clinical assessments and a body worn sensor. METHODS: The combination of the walker and the new armrest design are referred to as a better type (B-type). Clinical assessments and a motion analysis were performed on 34 elderly people (age, 83 ± 6 y/o) with a Five Times Sit-to-Stand Test (FTSST), a satisfaction survey and an inertial measurement unit (IMU) attached to the trunk to measure the acceleration data when using B-type and N-type during STS. RESULTS: The FTSST result shows that the B-type can reduce about 5 s spending time of elderly people during STS and 63.7% of subjects were more satisfied on the B-type than the N-type. According to the IMU, the result reveals that the B-type can provide subjects higher peak-peak anterio-posterior acceleration, peak flexion acceleration and peak extension acceleration during STS. CONCLUSION: There is a better assistance during STS when using our new armrests design combined with the commercial product which could provide larger acceleration to perform sit-to-stand.

Biochemical characterization and structural analysis of a bifunctional cellulase/xylanase from Clostridium thermocellum.

We expressed an active form of CtCel5E (a bifunctional cellulase/xylanase from Clostridium thermocellum), performed biochemical characterization, and determined its apo- and ligand-bound crystal structures. From the structures, Asn-93, His-168, His-169, Asn-208, Trp-347, and Asn-349 were shown to provide hydrogen-bonding/hydrophobic interactions with both ligands. Compared with the structures of TmCel5A, a bifunctional cellulase/mannanase homolog from Thermotoga maritima, a flexible loop region in CtCel5E is the key for discriminating substrates. Moreover, site-directed mutagenesis data confirmed that His-168 is essential for xylanase activity, and His-169 is more important for xylanase activity, whereas Asn-93, Asn-208, Tyr-270, Trp-347, and Asn-349 are critical for both activities. In contrast, F267A improves enzyme activities.

Identification, synthesis, and evaluation of new neuraminidase inhibitors.

High-throughput screening was performed on ∼6800 compounds to identify KR-72039 as an inhibitor of H1N1 and H5N1 neuraminidases (NAs). Structure-activity relationship studies led to 3e, which inhibited H5N1 NA with an IC50 of 2.8 µM and blocked viral replication. Docking analysis shows that compounds bind to loop-430 around the NA active site. Compound 3l additionally inhibited H7N9 NA, making it a dual inhibitor of N1- and N2-type NAs.

Targeting the XIAP/caspase-7 complex selectively kills caspase-3-deficient malignancies.

Caspase-3 downregulation (CASP3/DR) in tumors frequently confers resistance to cancer therapy and is significantly correlated with a poor prognosis in cancer patients. Because CASP3/DR cancer cells rely heavily on the activity of caspase-7 (CASP7) to initiate apoptosis, inhibition of activated CASP7 (p19/p12-CASP7) by X-linked inhibitor of apoptosis protein (XIAP) is a potential mechanism by which apoptosis is prevented in those cancer cells. Here, we identify the pocket surrounding the Cys246 residue of p19/p12-CASP7 as a target for the development of a protein-protein interaction (PPI) inhibitor of the XIAP:p19/p12-CASP7 complex. Interrupting this PPI directly triggered CASP7-dependent apoptotic signaling that bypassed the activation of the apical caspases and selectively killed CASP3/DR malignancies in vitro and in vivo without adverse side effects in nontumor cells. Importantly, CASP3/DR combined with p19/p12-CASP7 accumulation correlated with the aggressive evolution of clinical malignancies and a poor prognosis in cancer patients. Moreover, targeting of this PPI effectively killed cancer cells with multidrug resistance due to microRNA let-7a-1-mediated CASP3/DR and resensitized cancer cells to chemotherapy-induced apoptosis. These findings not only provide an opportunity to treat CASP3/DR malignancies by targeting the XIAP:p19/p12-CASP7 complex, but also elucidate the molecular mechanism underlying CASP3/DR in cancers.

Control activity of yeast geranylgeranyl diphosphate synthase from dimer interface through H-bonds and hydrophobic interaction.

Previously we showed that yeast geranylgeranyl diphosphate synthase (GGPPS) becomes an inactive monomer when the first N-terminal helix involved in dimerization is deleted. This raises questions regarding why dimerization is required for GGPPS activity and which amino acids in the dimer interface are essential for dimerization-mediated activity. According to the GGPPS crystal structure, three amino acids (N101, N104, and Y105) located in the helix F of one subunit are near the active site of the other subunit. As presented here, when these residues were replaced individually with Ala caused insignificant activity changes, N101A/Y105A and N101A/N104A but not N104A/Y105A showed remarkably decreased k(cat) values (200-250-fold). The triple mutant N101A/N104A/Y105A displayed no detectable activity, although dimer was retained in these mutants. Because N101 and Y105 form H-bonds with H139 and R140 in the other subunit, respectively, we generated H139A/R140A double mutant and found it was inactive and became monomeric. Therefore, the multiple mutations apparently influence the integrity of the catalytic site due to the missing H-bonding network. Moreover, Met111, also on the highly conserved helix F, was necessary for dimer formation and enzyme activity. When Met111 was replaced with Glu, the negative-charged repulsion converted half of the dimer into a monomer. In conclusion, the H-bonds mainly through N101 for maintaining substrate binding stability and the hydrophobic interaction of M111 in dimer interface are essential for activity of yeast GGPPS.

Mutations in the substrate entrance region of ß-glucosidase from Trichoderma reesei improve enzyme activity and thermostability.

ß-Glucosidase (EC 3.2.1.21) plays an essential role in biofuel production since it can cleave ß-1,4-glycosidic bond to convert cellobiose into fermentable glucose. Based on the structure of Trichoderma reesei ß-glucosidase 2 (TrBgl2) we solved, the amino acids in the outer channel of active site were mutated in this study. Mutants P172L and P172L/F250A showed the most enhanced k(cat)/K(m) and k(cat) values by 5.3- and 6.9-fold, respectively, compared to the wild type (WT) toward 4-nitrophenyl-ß-D-glucopyranoside (p-NPG) substrate at 40°C. L167W and P172L/F250A mutations resulted in shift of optimal temperature to 50°C, at which WT was almost inactive. However, thin-layer chromatography analysis revealed that mutant L167W had the best synergism with T. reesei cellulases on degrading cellulosic substrates into glucose. This study enhances our understanding on the roles of amino acids in the substrate entrance region away from the active site and provides engineered T. reesei ß-glucosidases with better activity and/or thermostability to hydrolyze cellobiose.

[Improving patient safety: acupuncture therapy administered in the rehabilitation department].

BACKGROUND: Therapies that combine Chinese and western medicine is applied particularly often on patients in rehabilitation departments to reduce disease and illness recovery times. Acupuncture (fine needle piercing) is a widely applied traditional Chinese therapeutic approach. However, accidents including leaving needles in the patient's body and patient fainting due to carelessness or inadequate nursing training have raised concerns about the efficacy of acupuncture. PURPOSE: This article was written to recommend ways to improve the safety of acupuncture applied to patients in rehabilitation departments. RESOLUTION: The authors developed standard operating procedures, nursing records, double-checking requirements, and on-the-job training courses. RESULT: After implementation of recommended resolutions, nursing staff cognition rose from 9.6 (63.8%) to 14.5 points (96.6%); the Traditional Chinese Medicine (TCM) nursing skill accuracy rate rose from 93 (58.1%) to 144 points (90.0%); and accident incidents fell from 6 (0.9%; 2008.1-2009.1) to 0 (2009.4.1-4.30). CONCLUSION: Implementing resolution recommendations effectively enhance patient safety.

Construction and characterization of different fusion proteins between cellulases and ß-glucosidase to improve glucose production and thermostability.

A ß-glucosidase from Clostridium cellulovorans (CcBG) was fused with one of three different types of cellulases from Clostridium thermocellum, including a cellulosomal endoglucanase CelD (CtCD), a cellulosomal exoglucanase CBHA (CtCA) and a non-cellulosomal endoglucanase Cel9I (CtC9I). Six bifunctional enzymes were constructed with either ß-glucosidase or cellulase in the upstream. CtCD-CcBG showed the favorable specific activities on phosphoric acid swollen cellulose (PASC), an amorphous cellulose, with more glucose production (2 folds) and less cellobiose accumulation (3 folds) when compared with mixture of the single enzymes. Moreover, CtCD-CcBG had significantly improved thermal stability with a melting temperature (T(m)) of 10.9°C higher than that of CcBG (54.5°C) based on the CD unfolding experiments. This bifunctional enzyme is thus useful in industrial application to convert cellulose to glucose.

Spinal dysraphism: a cross-sectional and retrospective multidisciplinary clinic-based study.

BACKGROUND: Spinal dysraphism is a common birth defect that causes different kinds of secondary impairments, including joint deformities, reduced mobility, and bowel/bladder dysfunction. Due to the diversity in terminology, cultural/ethnic differences, and medical policies, prior study results cannot be generalized to all populations. Therefore, we performed this study to define the characteristics of patients in Taiwan with spinal dysraphism. METHODS: Patients diagnosed with a myelomeningocele or lipomyelomeningocele were identified from the database of our spinal dysraphism multidisciplinary clinic. A cross-sectional study was conducted by telephone interview and retrospective chart review. Clinical characteristics, such as neurologic level, orthopedic deformities, assistive device use, and level of ambulation, were collected. Spearman's correlation (r) tests were performed between ambulation or neurologic level and other variables. RESULTS: Seventy-eight subjects were included in the current study. Subjects with myelomeningoceles had more severe neurologic involvement, poorer ambulation outcome, and higher rates of orthopedic deformities, assistive device use, lower hand function, and bowel/bladder dysfunction. The correlation test revealed that the level of ambulation was negatively influenced by a higher neurologic level, a history of shunt placement, and various orthopedic deformities. Neurologic level also had widespread influence on history of shunt placement, orthopedic deformities, assistive device use, the need for additional assistive devices, aggressiveness of assistive devices, and bowel/bladder dysfunction. CONCLUSION: For patients with spinal dysraphism, the neurologic level is the most important prognostic factor for many other clinical characteristics, including ambulation status.