fNIRS-based brain functional response to robot-assisted training for upper-limb in stroke patients with hemiplegia

BackgroundRobot-assisted therapy (RAT) has received considerable attention in stroke motor rehabilitation. Characteristics of brain functional response associated with RAT would provide a theoretical basis for choosing the appropriate protocol for a patient. However, the cortical response induced by RAT remains to be fully elucidated due to the lack of dynamic brain functional assessment tools.ObjectiveTo guide the implementation of clinical therapy, this study focused on the brain functional responses induced by RAT in patients with different degrees of motor impairment.MethodsA total of 32 stroke patients were classified into a low score group (severe impairment, n = 16) and a high score group (moderate impairment, n = 16) according to the motor function of the upper limb and then underwent RAT training in assistive mode with simultaneous cerebral haemodynamic measurement by functional near-infrared spectroscopy (fNIRS). Functional connectivity (FC) and the hemisphere autonomy index (HAI) were calculated based on the wavelet phase coherence among fNIRS signals covering bilateral prefrontal, motor and occipital areas.ResultsSpecific cortical network response related to RAT was observed in patients with unilateral moderate-to-severe motor deficits in the subacute stage. Compared with patients with moderate dysfunction, patients with severe impairment showed a wide range of significant FC responses in the bilateral hemispheres induced by RAT with the assistive mode, especially task-related involvement of ipsilesional supplementary motor areas.ConclusionUnder assisted mode, RAT-related extensive cortical response in patients with severe dysfunction might contribute to brain functional organization during motor performance, which is considered the basic neural substrate of motor-related processes. In contrast, the limited cortical response related to RAT in patients with moderate dysfunction may indicate that the training intensity needs to be adjusted in time according to the brain functional state. fNIRS-based assessment of brain functional response assumes great importance for the customization of an appropriate protocol training in the clinical practice

Vigilance task-related change in brain functional connectivity as revealed by wavelet phase coherence analysis of near-infrared spectroscopy signals

This study aims to assess the vigilance task-related change in connectivity in healthy adults using wavelet phase coherence (WPCO) analysis of near-infrared spectroscopy signals (NIRS). NIRS is a non-invasive neuroimaging technique for assessing brain activity. Continuous recordings of the NIRS signals were obtained from the prefrontal cortex (PFC) and sensorimotor cortical areas of 20 young healthy adults (24.9±3.3 years) during a 10-min resting state and a 20-min vigilance task state. The vigilance task was used to simulate driving mental load by judging three random numbers (i.e., whether odd numbers). The task was divided into two sessions: the first 10 minutes (Task t1) and the second 10 minutes (Task t2). The WPCO of six channel pairs were calculated in five frequency intervals: 0.6–2 Hz (I), 0.145–0.6 Hz (II), 0.052–0.145 Hz (III), 0.021–0.052 Hz (IV), and 0.0095–0.021 Hz (V). The significant WPCO formed global connectivity (GC) maps in intervals I and II and functional connectivity (FC) maps in intervals III to V. Results show that the GC levels in interval I and FC levels in interval III were significantly lower in the Task t2 than in the resting state (p < 0.05), particularly between the left PFC and bilateral sensorimotor regions. Also, the reaction time shows an increase in Task t2 compared with that in Task t1. However, no significant difference in WPCO was found between Task t1 and resting state. The results showed that the change in FC at the range of 0.6-2 Hz was not attributed to the vigilance task pe se, but the interaction effect of vigilance task and time factors. The findings suggest that the decreased attention level might be partly attributed to the reduced GC levels between the left prefrontal region and sensorimotor area. The present results provide a new insight into the vigilance task-related brain activity

Study on the Changes of Intestinal Flora and Its Metabolite Phenylacetylglutamine in Patients with Chronic Heart Failure

Background The intestinal flora and its metabolites play an important role in the pathology of chronic heart failure (CHF), which is a severe manifestation or terminal stage of various cardiovascular diseases. Increasing evidence has shown that dysbiosis of the intestinal flora and its metabolites can lead to bacterial translocation, release of mediators, inflammatory response and consequently aggravation of CHF. Objective To analyze the changes of intestinal flora and its metabolite phenylacetylglutamine (PAGln) in patients with CHF and explore the role played by gut microbiota in heart failure. Methods A total of 58 patients with heart failure admitted to the Department of Cardiology of the South Branch of the Sixth People&apos;s Hospital of Shanghai Jiaotong University were selected as the CHF group, and 46 patients with the same CHF risk factors but without clinical symptoms and past medical history of CHF were selected as the control group from June 2021 to June 2022. Plotting ROC curves of brain natriuretic peptide (BNP) and PAGln for the diagnosis of CHF. The abundance and diversity of intestinal flora in the two groups were analyzed using 16S rRNA sequencing. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used to detect PAGln concentrations in the plasma of samples from both two groups. Results The left ventricular end-systolic diameter (LVESD), left ventricular end-diastolic diameter (LVEDD), BNP, and PAGln in the CHF group were higher than the control group, and the left ventricular ejection fraction (LVEF) was lower than the control group (P&lt;0.05). The area under curve (AUC) of BNP and PAGln levels for the diagnosisof CHF patients was 0.995 and 0.913, respectively. Venn diagram showed that the number of OTUs specific to the CHF group was less than the control group. Alpha diversity analysis showed that the Chao1 index was lower in the CHF group than the control group (P&lt;0.05). &#x03B2; diversity analysis showed that the overall structure of the intestinal flora differed between the two groups. At the genus level, the relative abundances of Escherichia-Shigella, Megamonas, Klebsiella, Bifidobacterium, Parabacteroides, and Romboutsia were higher in the CHF group than the control group (P&lt;0.05), and the relative abundances of Solimonas and Dorea were lower than the control group (P&lt;0.05). The results of LEfSe analysis showed that Lachnospiraceae, Solimonadaceae, Solimonas, Dorea, and Burkholderiaceae were elevated in the control group (P&lt;0.05), and Enterobacteriaceae, Escherichia, Bifidobacterium, Bifidobacteriaceae, Klebsiella, Lactobacillaceae, Lactobacillus, Megamonas, Rikenellaceae, Alistipes, Parabacteroides, and Tannerellaceae were elevated in the CHF group (P&lt;0.05). Typical correlation analysis (CCA) showed that BNP, PAGln, LVEDD, and LVESD were significantly correlated with the CHF group, with BNP having the greatest effect on community changes. Correlation analysis showed that Escherichia-Shigella was positively correlated with BNP and PAGln (P&lt;0.05) ; Bacteroides was negatively correlated with BNP; Romboutsia, Fusobacterium, and Phascolarctobacterium were negatively correlated with BNP and PAGln (P&lt;0.05) . Conclusion The structural composition of the intestinal flora in patients with CHF was significantly different from the patients with the same co-morbidities but without clinical manifestations and previous medical history of CHF, with a decrease in flora diversity and a significant increase in the abundance of pathogenic intestinal bacteria, which may lead to an increase in the level of PAGln in CHF patients and participate in the development of CHF

Fabrication of porous SiC(y) (core)/C (shell) fibres using a hybrid precursor of polycarbosilane and pitch

Porous SiCy (core)/C (shell) composite fibres have been fabricated using a simple KOH controlled-activation of SiCx fibres, which were pyrolyzed from polycarbosilane-pitch blend fibres. Effects of activation conditions and pyrolysis temperatures were studied. There are distinctive interfaces observed on the cross-sections of the co-axial fibres, where Si content varies gradually from the core to the shell. The etching of Si follows a slow “core-reducing” process in N2, while in CO2, cracks are frequently observed on the shells due to the accelerated activations. V-shaped Si-free carbon fibres could be obtained when a lower pyrolysis temperature was used to produce the SiCx fibres.Microporous carbon (MC)-based materials have received intensive attention in the context of physisorption for hydrogen storage in the coming era of hydrogen economy [1]. Recently, tremendous efforts have been made to prepare MCs with high specific surface areas (SSAs) and developed porosity, typically, high SSAs can be achieved by controlled-activation of carbon precursors [3], template-assembling using Zeolites [2], or metal-extracting from carbides (carbide-derived carbons, CDCs) [4]. All these candidates have shown brilliant future for the hydrogen storage. However, the amounts of hydrogen adsorbed are still quite limited under high pressure and ambient temperature conditions [5]. Fortunately, the modification of C surfaces through incorporation of functional groups or dopants facilitates increasing binding energy of hydrogen with MCs and most recently, B-substituted MC has been synthesized and exhibited increased H2 storage capacity, 3.2 wt.%, almost double that of MC with similar SSA [6]. As simulated [7], Si should be a good alternative dopant due to the much higher binding energy of hydrogen with SiC. However, SiC usually has low SSA and hard to fabricate porous structure. We here reported a simple one-step activation to produce porous SiC fibres using a hybrid precursor of polycarbosilane (PCS) and pitch. Interestingly, novel core–shell structured materials were obtained. The influences of processing parameters on the cross-section morphologies were discussed in this letter.Polycarbosilane and pitch were mixed with a weight ratio of 55%/45%, melt-spun into green fibres, cured in air and pyrolyzed in N2 giving C-rich SiCx fibres. Then the SiCx fibres were loaded with KOH at a definite impregnation mass ratio (R = wt. KOH/wt. fibres), and activated in N2 or CO2 at a defined temperature/duration (for experimental details, see Supplementary information).<br/

Protective effect of curcumin against myocardium injury in ischemia reperfusion rats

Context: Curcumin has long been used as a condiment and a traditional medicine worldwide. Objective: The current study investigates the possible protective effect of curcumin on heart function in myocardium ischemia-reperfusion (MIR) rats. Materials and methods: We fed Sprague–Dawley (SD) rats (10 in each group) either curcumin (10, 20 or 30 mg/kg/d) or saline. Twenty days later, the rats were subjected to myocardial injuries by ligating the left anterior descending coronary artery (60 min), and subsequently, the heart (3 h) reperfused by releasing the ligation. Then, lipid profile, lipid peroxidation products, antioxidant enzymes and gene expression were assessed in myocardium tissue. Results: Only the rats that were supplemented with curcumin (10, 20 or 30 mg/kg/d) showed significant (p < 0.05) reductions in oxidative stress (3-fold), infarct size (2.5-fold), which was smaller than that of the control group. The percentage of infarct size in MIR rats with curcumin at 10, 20 or 30 mg/kg/d decreased (from 49.1% to 18.3%) compared to ischemia-reperfusion (I/R). The enhanced phosphorylation of STAT3 was further strengthened by curcumin (10, 20 or 30 mg/kg/d) in a dose-dependent manner. Discussion and conclusion: Curcumin intake might reduce the risk of coronary heart disease by stimulating JAK2/STAT3 signal pathway, decreasing oxidative damage and inhibiting myocardium apoptosis

Electrospun PAN/MAPbI3 Composite Fibers for Flexible and Broadband Photodetectors

Methylammonium lead triiodide perovskite (CH3NH3PbI3, MAPbI3) has been emerging as an easy processing and benign defect material for optoelectronic devices. Fiber-like perovskite materials are especially in demand for flexible applications. Here we report on a kind of polyacrylonitrile (PAN)/MAPbI3 composite fiber, which was electrospun from the mixing solution of PAN and MAPbI3. The absorption edge and optical gap of the PAN/MAPbI3 composite fibers can be easily tuned as the ratio of the perovskite changes. Both the moisture stability and the thermal stability of the perovskite are improved with the protection of PAN polymers. Flexible photodetectors based on this perovskite fiber were fabricated and analyzed. The photoresponse of the detector was highly sensitive to broadband visible light, and reached 6.5 &mu;A W&minus;1 at 700 nm with a voltage bias of 10 V. Compared with pure MAPbI3 photodetectors, this composite fiber photodetector has much-improved stability and flexibility, which can even be used to detect motion-related angular changes

Finite element analysis of biomechanical effects of total ankle arthroplasty on the foot

Background: Total ankle arthroplasty is gaining popularity as an alternation to ankle arthrodesis for end-stage ankle arthritis. Owing to the complex anatomical characteristics of the ankle joint, total ankle arthroplasty has higher failure rates. Biomechanical exploration of the effects of total ankle arthroplasty on the foot and ankle is imperative for the precaution of postoperative complications. The objectives of this study are (1) to investigate the biomechanical differences of the foot and ankle between the foot with total ankle arthroplasty and the intact foot and (2) to investigate the performance of the three-component ankle prosthesis. Methods: To understand the loading environment of the inner foot, comprehensive finite element models of an intact foot and a foot with total ankle arthroplasty were developed to simulate the stance phase of gait. Motion analysis on the model subject was conducted to obtain the boundary and loading conditions. The model was validated through comparison of plantar pressure and joint contact pressure between computational prediction and experimental measurement. A pressure mapping system was used to measure the plantar pressure during balanced standing and walking in the motion analysis experiment, and joint contact pressure at the talonavicular joint was measured in a cadaver foot. Results: Plantar pressure, stress distribution in bones and implants and joint contact loading in the two models were compared, and motion of the prosthesis was analysed. Compared with the intact foot model, averaged contact pressure at the medial cuneonavicular joint increased by 67.4% at the second-peak instant. The maximum stress in the metatarsal bones increased by 19.8% and 31.3% at the mid-stance and second-peak instants, respectively. Force that was transmitted in three medial columns was 0.33, 0.53 and 1.15 times of body weight, respectively, at the first-peak, mid-stance and second-peak instants. The range of motion of the prosthetic ankle was constrained in the frontal plane. The lateral side of the prosthesis sustained higher loading than the medial side. Conclusion: Total ankle arthroplasty resulted in great increase of contact pressure at the medial cuneonavicular joint, making it sustain the highest contact pressure among all joints in the foot. The motion of the prosthesis was constrained in the frontal plane, and asymmetric loading was distributed in the bearing component of the ankle prosthesis in the mediolateral direction. The translational potential of this article: Biomechanical variations resulted from total ankle arthroplasty may contribute to negative postoperative outcomes. The exploration of the biomechanical performance in this study might benefit the surgeons in the determination of surgical protocols to avoid complications. The analysis of the performance of the ankle prosthesis could enhance the knowledge of prosthetic design

Alterations in the coupling functions between cerebral oxyhaemoglobin and arterial blood pressure signals in post-stroke subjects.

Cerebral autoregulation (CA) is the complex homeostatic regulatory relationship between blood pressure (BP) and cerebral blood flow (CBF). This study aimed to analyze the frequency-specific coupling function between cerebral oxyhemoglobin concentrations (delta [HbO2]) and mean arterial pressure (MAP) signals based on a model of coupled phase oscillators and dynamical Bayesian inference. Delta [HbO2] was measured by 24-channel near-infrared spectroscopy (NIRS) and arterial BP signals were obtained by simultaneous resting-state measurements in patients with stroke, that is, 9 with left hemiparesis (L-H group), 8 with right hemiparesis (R-H group), and 17 age-matched healthy individuals as control (healthy group). The coupling functions from MAP to delta [HbO2] oscillators were identified and analyzed in four frequency intervals (I, 0.6-2 Hz; II, 0.145-0.6 Hz; III, 0.052-0.145 Hz; and IV, 0.021-0.052 Hz). In L-H group, the CS from MAP to delta [HbO2] in interval III in channel 8 was significantly higher than that in healthy group (p = 0.003). Compared with the healthy controls, the coupling in MAP→delta [HbO2] showed higher amplitude in interval I and IV in patients with stroke. The increased CS and coupling amplitude may be an evidence of impairment in CA, thereby confirming the presence of impaired CA in patients with stroke. In interval III, the CS in L-H group from MAP to delta [HbO2] in channel 16 (p = 0.001) was significantly lower than that in healthy controls, which might indicate the compensatory mechanism in CA of the unaffected side in patients with stroke. No significant difference in region-wise CS between affected and unaffected sides was observed in stroke groups, indicating an evidence of globally impaired CA. These findings provide a method for the assessment of CA and will contribute to the development of therapeutic interventions in stroke patients