Design and Experimental Research of Implantable Lower Esophageal Sphincter Stimulator Based on Android Bluetooth.

The aim of this study is to design an implantable Lower Esophageal Sphincter (LES) stimulator connected and controlled by an Android Bluetooth for the treatment of the gastroesophageal reflux disease (GERD). Then the animal experiments are carried out to evaluate the function of the system. The LES stimulator is composed of an external controller, an Android application (APP) via a smart phone and an implantable electronic device (IED). The external controller is designed to receive the settings parameters information sent by the Android APP via a Bluetooth module, and then is programmed to generate specific electrical stimulation pulses to the LES. The Android APP controls the start and stop of stimulation and the settings of stimulation parameters. The in vivo IED consists of a bipolar stimulating lead, a bipolar head connector and a receiving module. The bipolar stimulating lead is constructed of biocompatible materials: platinum-iridium electrodes which are coated with parylene and an outer silicone rubber sheathing. The size of the receiving module has been significantly decreased to 20×20×2 mm3, which is packaged by polydimethylsiloxane (PDMS) and proposed to deliver stimulation pulses from the external controller to the implantable lead. The one-month implantation experiment on rabbits has been performed to evaluate the LES stimulator. The results indicate that the proposed LES stimulator meets the requirements of the functions, effectiveness and safety.

Evaluation of analgesic and anti-inflammatory activities of Rubia cordifolia L. by spectrum-effect relationships.

The objective of the current work was to evaluate the spectrum-effect relationships between high-performance liquid chromatography fingerprints and analgesic and anti-inflammatory effects of Rubia cordifolia L. extract (RCE), and to identify active components of RCE. Chemical fingerprints of ten batches of RC from various sources were obtained by HPLC, and similarity and hierarchical clustering analyses were carried out. Pharmacodynamic assays were performed in adjuvant-induced arthritis rat model to assess the analgesic and anti-inflammatory properties of RCE. The spectrum-effect relationships between chemical fingerprints and the analgesic and anti-inflammatory effects of RCE were established by gray correlation analysis. UPLC-ESI-MS was used to identify the structures of potential active components, by reference standards comparison. The results showed that a close correlation existed between chemical fingerprints with analgesic and anti-inflammatory activities, and alizarin, 6-hydroxyrubiadin, purpurin and rubiadin might be the active constituents of RCE. In addition, RCE attenuated pathological changes in adjuvant-induced arthritis. The current findings provide a strong basis for combining chemical fingerprints with analgesic and anti-inflammatory activities in assessing the spectrum-effect relationships of RCE.

Phosphorus speciation in sewage sludge and the sludge-derived biochar by a combination of experimental methods and theoretical simulation.

Sewage sludge is an inevitable byproduct from municipal wastewater treatment processes and conversion of sewage sludge into high value-added biochar is an effective strategy for resource utilization of sewage sludge. The characterization on P speciation is important to control the practical applications and environmental behavior of the sewage sludge and its derived biochar. The mobility and bioavailability of P is closely related to its speciation, but knowledge gap in P speciation is still existed which needs to be narrowed by a systematic study including existing experimental methods and techniques as well as theoretical prediction. To achieve a comprehensive understanding of P speciation, this study conducted a series of research combining conventional fractionation of P with consideration of major concomitant elements (Al, Ca, Fe), advanced analytical techniques (solution and solid-state 31P nuclear magnetic resonance (NMR), X-ray diffraction (XRD)), and theoretical simulation with respect to solubility of major elements in different acid-base extractants. Results showed that Ca and Fe were dominantly extracted by HCl whereas P and Al were both NaOH- and HCl-soluble. Inorganic orthophosphates were detected as predominant molecular configurations of P from solution 31P NMR spectra, while the existence of calcium and aluminum orthophosphates was revealed by solid-state 31P NMR. Moreover, the poor-crystalline AlPO4 mineral was further evidenced by XRD patterns of the sewage sludge and biochar. Finally, a theoretical simulation of P-containing minerals was performed on the basis of results above, which suggested the existence of variscite/berlinite and amorphous Ca3(PO4)2 in the sludge and biochar. This study does not only explore the P speciation in the sewage sludge and its derived biochar, but also provides a methodology for further research on P speciation. Through the intensive study on the environmental behavior of P, this work might further contribute to the fundamental knowledge basis for the recycle of P during integrate waste management.

Electromyographic bridge for promoting the recovery of hand movements in subacute stroke patients: A randomized controlled trial.

OBJECTIVE: The electromyographic bridge (EMGB) detects surface electromyographic signals from a non-paretic limb. It then generates electric pulse trains according to the electromyographic time domain features, which can be used to stimulate a paralysed or paretic limb in real time. This strategy can be used for the contralateral control of neuromuscular electrical stimulation (NMES) to improve motor function after stroke. The aim of this study was to compare the treat-ment effects of EMGB vs cyclic NMES on wrist and finger impairments in subacute stroke patients. METHODS: A total of 42 hemiplegic patients within 6 months of their cerebrovascular accidents were randomly assigned to 4-week treatments with EMGB or cyclic NMES. Each group underwent a standard rehabilitation programme and 10 sessions per week of hand training with EMGB or cyclic NMES. Outcome measures were: Brunnstrom stage, upper extremity components of the Fugl-Meyer Assessment, Motor Status Scale, voluntary surface electromyographic ratio and active range of motion of the wrist and finger joints. RESULTS: The EMGB group showed significantly greater improvements than the cyclic NMES group on the following measures: Brunnstrom stages for the hand, upper extremity - Fugl-Meyer Assessment, Motor Status Scale, and the voluntary surface electromyographic ratio of wrist and finger extensors. Eleven and 4 participants of the EMGB group who had no active wrist and finger movements, respectively, at the start of the treatment could perform measurable wrist and finger extensions after EMGB training. The corresponding numbers in the cyclic NMES group were only 4 and 1. CONCLUSION: In the present group of subacute stroke patients, the results favour EMGB over cyclic NMES for augmenting the recovery of volitional wrist and finger motion.

The Principle of the Micro-Electronic Neural Bridge and a Prototype System Design.

The micro-electronic neural bridge (MENB) aims to rebuild lost motor function of paralyzed humans by routing movement-related signals from the brain, around the damage part in the spinal cord, to the external effectors. This study focused on the prototype system design of the MENB, including the principle of the MENB, the neural signal detecting circuit and the functional electrical stimulation (FES) circuit design, and the spike detecting and sorting algorithm. In this study, we developed a novel improved amplitude threshold spike detecting method based on variable forward difference threshold for both training and bridging phase. The discrete wavelet transform (DWT), a new level feature coefficient selection method based on Lilliefors test, and the k-means clustering method based on Mahalanobis distance were used for spike sorting. A real-time online spike detecting and sorting algorithm based on DWT and Euclidean distance was also implemented for the bridging phase. Tested by the data sets available at Caltech, in the training phase, the average sensitivity, specificity, and clustering accuracies are 99.43%, 97.83%, and 95.45%, respectively. Validated by the three-fold cross-validation method, the average sensitivity, specificity, and classification accuracy are 99.43%, 97.70%, and 96.46%, respectively.

A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features.

OBJECTIVE: Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. APPROACH: We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. MAIN RESULTS: The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. SIGNIFICANCE: Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle force reproduction and muscle fatigue reduction.

Design of a pulse-triggered four-channel functional electrical stimulator using complementary current source and time division multiplexing output method.

In this paper, a four-channel pulse-triggered functional electrical stimulator using complementary current source and time division output method is proposed for the research and application of functional electrical stimulation (FES). The high-voltage compliance and output impedance is increased by adopting the complementary current source, which can also realize the linear voltage-to-current conversion and high channel isolation. A high-voltage analog switch chip MAX14803, combined with a FIFO queue algorithm in the microprocessor, is used to setup the H-bridge and multiplexers for the four-channel time division multiplexing output. With this method, the size and cost of the key components are reduced greatly. The stimulating core circuit area is 30 × 50 mm(2). According to the experiments, the stimulator can achieve the four-channel charge-balanced biphasic stimulation with a current range between 0 and 60 mA and a single-phase pulse amplitude up to 60 V.

[Study on display of acupuncture meridian based on electric signal transfer characteristics].

OBJECTIVE: To analyze the real-time effects of electroacupuncture (EA) stimulation by means of multiport network theory and measurement of the electric signals transfer coefficient, so as to explore a way for determining the running course of acupuncture meridian and for characterizing its physiological activities in the living body. METHODS: The body was modeled as a complex inhomogeneous 3-dimensions multi-port network, and the meridians were assumed to be "the most smoothly channels for signal transmission". Experiments were performed in 12 beheaded toads whose forelimbs and hindlimbs were divided into proportional coordinates. A concentric electrode with a conical tip was inserted into the toad leg for electrical stimulation of the local muscle, and another electrode alike was inserted into different spots of the limbs to detect the spreading signals in a 3-dimensional scanning mode. Following detecting the response electric voltage values of various spots and calculating their transfer coefficients, the spots which acquired a maximum signal value were considered to be the "acupoints". The imaginary connective lines passing the "acupoints" were regarded as the running courses of acupuncture meridians. RESULTS: A total of twelve 3-dimensional curves were detected based on the connected lines of electric signal transfer function extremum spots 2 mm beneath the skin of the ipsilateral fore- and hind-limbs of 12 spinal toads. CONCLUSION: The present study initially validates the feasibility of electric signal transfer coefficient measurement for displaying the running course of acupuncture meridian in the toad fore- and hindlimbs.

[Study on signal transmission characteristics of meridian based on electrical network theory and experiments].

Study on features of acupoints with resistance test in the past half century is reviewed in this article. Mechanism and technology of the method are introduced as well as its shortcomings. The determination method of signal transmission along meridians with the combination of electrical network theories and practice is advanced. And the result of a series experiments on one meridian at the superficial part of the body are given as well. Thus, it is concluded that the signals of the point-in/point-out and the signals along a non-meridian path with the same distance are significantly different, which gives a verification of the feasibility of the method by using electrical network theories to set out characteristics of signal transmission along meridians dynamically.