Probing molecular pathways: Illuminating the connection between COVID-19 and Alzheimer's disease through the endocannabinoid system dynamics.

Our study investigates the molecular link between COVID-19 and Alzheimer's disease (AD). We aim to elucidate the mechanisms by which COVID-19 may influence the onset or progression of AD. Using bioinformatic tools, we analyzed gene expression datasets from the Gene Expression Omnibus (GEO) database, including GSE147507, GSE12685, and GSE26927. Intersection analysis was utilized to identify common differentially expressed genes (CDEGs) and their shared biological pathways. Consensus clustering was conducted to group AD patients based on gene expression, followed by an analysis of the immune microenvironment and variations in shared pathway activities between clusters. Additionally, we identified transcription factor-binding sites shared by CDEGs and genes in the common pathway. The activity of the pathway and the expression levels of the CDEGs were validated using GSE164805 and GSE48350 datasets. Six CDEGs (MAL2, NECAB1, SH3GL2, EPB41L3, MEF2C, and NRGN) were identified, along with a downregulated pathway, the endocannabinoid (ECS) signaling pathway, common to both AD and COVID-19. These CDEGs showed a significant correlation with ECS activity (p < 0.05) and immune functions. The ECS pathway was enriched in healthy individuals' brains and downregulated in AD patients. Validation using GSE164805 and GSE48350 datasets confirmed the differential expression of these genes in COVID-19 and AD tissues. Our findings reveal a potential pathogenetic link between COVID-19 and AD, mediated by CDEGs and the ECS pathway. However, further research and multicenter evidence are needed to translate these findings into clinical applications.

Characterizing the coefficient of friction between a capsule robot and the colon.

OBJECTIVE: A capsule robot (CR) with an onboard active locomotion mechanism, has been developed as a promising alternative to colonoscopy due to its minimally-invasive advantage. Predicting the traction force and locomotion resistance of the CR, which are both the friction force, is significantly important for the CR development and control. However, a comprehensive study concerning the coefficient of friction (COF) in the colon, which is necessary for prediction, is not available in literature. This paper is dedicated to determining a quantitative COF equation in terms of the contact pressure, hoop strain, and sliding velocity. METHODS: The COFs of three commonly-used materials of the CR (i.e., PDMS, white and transparent ABS plastic), are measured under 144 different friction cases (6 contact pressures×4 hoop strains×6 sliding velocities). By analyzing the measurements, the influence law of the three factors on the COFs of the three materials is revealed, and based on which, a general COF equation involving eight fitted constants is determined. RESULTS: The determination coefficients of the COF equation for the three materials are up to 0.9822, 0.9286, and 0.9696, respectively. The COF equation is used to predict the traction force and locomotion resistance of a crawler CR, and the predicting results fit well with the measured ones. CONCLUSION: The COF equation can provide a correct COF for friction force prediction. SIGNIFICANCE: It is promising to enable a better force and locomotion control for the CR in the colon.

Scalp acupuncture regulates functional connectivity of cerebral hemispheres in patients with hemiplegia after stroke.

Background: Stroke is a common cause of acquired disability on a global scale. Patients with motor dysfunction after a stroke have a reduced quality of life and suffer from an economic burden. Scalp acupuncture has been proven to be an effective treatment for motor recovery after a stroke. However, the neural mechanism of scalp acupuncture for motor function recovery remains to be researched. This study aimed to investigate functional connectivity (FC) changes in region of interest (ROI) and other brain regions to interpret the neural mechanism of scalp acupuncture. Methods: Twenty-one patients were included and randomly divided into patient control (PCs) and scalp acupuncture (SAs) groups with left hemiplegia due to ischemic stroke, and we also selected 20 matched healthy controls (HCs). The PCs were treated with conventional Western medicine, while the SAs were treated with scalp acupuncture (acupuncture at the right anterior oblique line of vertex temporal). All subjects received whole-brain resting-state functional magnetic resonance imaging (rs-fMRI) scan before treatment, and the patients received a second scan after 14 days of treatment. We use the National Institutes of Health Stroke Scale (NIHSS) scores and the analyses of resting-state functional connectivity (RSFC) as the observational indicators. Results: The contralateral and ipsilateral cortex of hemiplegic patients with cerebral infarction were associated with an abnormal increase and decrease in basal internode function. An abnormal increase in functional connectivity mainly exists in the ipsilateral hemisphere between the cortex and basal ganglia and reduces the abnormal functional connectivity in the cortex and contralateral basal ganglia. Increased RSFC was observed in the bilateral BA6 area and bilateral basal ganglia and the connectivity between bilateral basal ganglia nuclei improved. However, the RSFC of the conventional treatment group only improved in the unilateral basal ganglia and contralateral BA6 area. The RSFC in the left middle frontal gyrus, superior temporal gyrus, precuneus, and other healthy brain regions were enhanced in SAs after treatment. Conclusion: The changes in functional connectivity between the cerebral cortex and basal ganglia in patients with cerebral infarction showed a weakening of the bilateral hemispheres and the enhancement of the connections between the hemispheres. Scalp acupuncture has the function of bidirectional regulation, which makes the unbalanced abnormal brain function state restore balance.

Wirelessly powered deformable electronic stent for noninvasive electrical stimulation of lower esophageal sphincter.

Electrical stimulation is a promising method to modulate gastrointestinal disorders. However, conventional stimulators need invasive implantation and removal surgeries associated with risks of infection and secondary injuries. Here, we report a battery-free and deformable electronic esophageal stent for wireless stimulation of the lower esophageal sphincter in a noninvasive fashion. The stent consists of an elastic receiver antenna infilled with liquid metal (eutectic gallium-indium), a superelastic nitinol stent skeleton, and a stretchable pulse generator that jointly enables 150% axial elongation and 50% radial compression for transoral delivery through the narrow esophagus. The compliant stent adaptive to the dynamic environment of the esophagus can wirelessly harvest energy through deep tissue. Continuous electrical stimulations delivered by the stent in vivo using pig models significantly increase the pressure of the lower esophageal sphincter. The electronic stent provides a noninvasive platform for bioelectronic therapies in the gastrointestinal tract without the need for open surgery.

Development of a Capsule Robot for Exploring the Colon.

A tether-less inchworm-like capsule robot (ILCR) is promising to enable a non-invasive exploration of the colon, while existing ILCRs show barely satisfactory movement performance because the colon environment is nonstructural. In this current study, we develop an enhanced ILCR based on a design rule of maximizing the achievable periodic stroke and minimizing the body length, with the aim of improving movement performance. By designing an axial compact expanding mechanism (EM), employing a novel linear mechanism (LM), and integrating a hollow-cylinder-like power source based on wireless power transmission (WPT), the enhanced ILCR achieves a periodic stroke of 38 mm within a small body length of 33 mm. Our experiments show that the EM and LM can work reliably in an ex-vivo colon with a lot of intestinal mucus, and the power source can safely supply a stable working voltage of 3.3 V even in the worst case. Being wirelessly controlled and powered, the enhanced ILCR shows satisfactory movement performance, with velocities of 15.8 cm/min, 12.1 cm/min, and 7.4 cm/min in a transparent tube, a tiled colon, and a suspended colon, respectively, promising to accomplish an exploration for the 1.5-m long colon within 30 min.

Design, Fabrication and Experiment of Double U-Beam MEMS Vibration Ring Gyroscope.

This study presents a new microelectromechanical system, a vibration ring gyroscope with a double U-beam (DUVRG), which was designed using a combination of mathematical analysis and the finite element method. First, a ring vibration resonator with eight double U-beam structures was developed, and 24 capacitive electrodes were designed for drive and sense according to the advantageous characteristics of a thin-shell vibrating gyroscope. Then, based on the elastic mechanics and thin-shell theory, a mathematical stiffness model of the double U-beam was established. The maximum mode resonant frequency error calculated by the DUVRG stiffness model, finite element analysis (FEA) and experiments was 0.04%. DUVRG structures were manufactured by an efficient fabrication process using silicon-on-glass (SOG) and deep reactive ion etching (DRIE), and the FEA value and theoretical calculation had differences of 5.33% and 5.36% with the measured resonant frequency value, respectively. Finally, the static and dynamic performance of the fabricated DUVRG was tested, and the bias instability and angular random walk were less than 8.86 (°)/h and 0.776 (°)/√h, respectively.

Locomotion enhancement of an inchworm-like capsule robot using long contact devices.

BACKGROUND: The inchworm-like capsule robot (CR), which consists of two anchoring mechanisms (AMs) and an extensor, is a promising device for exploring the human intestine. However, the slippery intestinal lumen can cause anchoring slippage and the visco-elastic intestine and mesentery can cause stroke loss, which both lower its locomotion performance. METHODS: This paper proposes a method for locomotion enhancement by optimizing the lengths of the contact devices that are installed at the tips of the AM. RESULTS: Theoretical analysis showed that a longer contact device was more beneficial to avoid slippage and reduce stroke loss, hence enhancing locomotion, which was then verified by ex vivo experiments. The 34.5 mm long contact devices enabled a locomotion efficiency of 54%, while it was only 21% when employing 5 mm long contact devices. CONCLUSIONS: The inchworm-like CR using long contact devices can enable a more efficient inspection of the intestine. Copyright © 2016 John Wiley & Sons, Ltd.

Locomotion Analysis of an Inchworm-Like Capsule Robot in the Intestinal Tract.

GOAL: Inchworm-like locomotion is one of the most common and effective approaches for exploring the intestinal tract. Here, we present a locomotion analysis for a typical inchworm-like capsule robot, which is composed of a locomotion unit and some functional modules that are installed at both ends. The locomotion unit consists of two clampers at both ends and an extensor at midsection, and the functional modules include the camera, microtools for diagnosis or therapy, etc. METHODS: By taking into account the intestinal deformation induced by the robot's action in every continuous locomotion step, a locomotion model correlating the locomotion efficiency with the design parameters (i.e., the periodic stroke, the lengths of the clampers, extensor, and functional modules) was built. RESULTS: Ex vivo experiments were conducted to validate the proposed model, and the experimental results basically agreed to the theoretical ones predicted by the model. CONCLUSION: The proposed locomotion model is effective in guiding the selection of the design parameters for improving the locomotion efficiency. SIGNIFICANCE: The inchworm-like capsule robot with higher locomotion efficiency will enable a more efficient diagnosis and therapy process for the intestinal tract.

Quantifying the complexity of human colonic pressure signals using an entropy measure.

Studying the complexity of human colonic pressure signals is important in understanding this intricate, evolved, dynamic system. This article presents a method for quantifying the complexity of colonic pressure signals using an entropy measure. As a self-adaptive non-stationary signal analysis algorithm, empirical mode decomposition can decompose a complex pressure signal into a set of intrinsic mode functions (IMFs). Considering that IMF2, IMF3, and IMF4 represent crucial characteristics of colonic motility, a new signal was reconstructed with these three signals. Then, the time entropy (TE), power spectral entropy (PSE), and approximate entropy (AE) of the reconstructed signal were calculated. For subjects with constipation and healthy individuals, experimental results showed that the entropies of reconstructed signals between these two classes were distinguishable. Moreover, the TE, PSE, and AE can be extracted as features for further subject classification.

Characteristics of locomotion efficiency of an expanding-extending robotic endoscope in the intestinal environment.

Robotic endoscopes with locomotion ability are among the most promising alternatives to traditional endoscopes; the locomotion ability is an important factor when evaluating the performance of the robot. This article describes the research on the characteristics of an expanding-extending robotic endoscope's locomotion efficiency in real intestine and explores an approach to improve the locomotion ability in this environment. In the article, the robot's locomotion efficiency was first calculated according to its gait in the gut, and the reasons for step losses were analyzed. Next, dynamical models of the robot and the intestine were built to calculate the step losses caused by failed anchoring and intestinal compression/extension. Based on the models and the calculation results, methods for reducing step losses were proposed. Finally, a series of ex vivo experiments were carried out, and the actual locomotion efficiency of the robot was analyzed on the basis of the theoretical models. In the experiment, on a level platform, the locomotion efficiency of the robot varied between 34.2% and 63.7%; the speed of the robot varied between 0.62 and 1.29 mm/s. The robot's efficiency when climbing a sloping intestine was also tested and analyzed. The proposed theoretical models and experimental results provide a good reference for improving the design of robotic endoscopy.

A wireless capsule system with ASIC for monitoring the physiological signals of the human gastrointestinal tract.

This paper presents the design of a wireless capsule system for monitoring the physiological signals of the human gastrointestinal (GI) tract. The primary components of the system include a wireless capsule, a portable data recorder, and a workstation. Temperature, pH, and pressure sensors; an RF transceiver; a controlling and processing application specific integrated circuit (ASIC); and batteries were applied in a wireless capsule. Decreasing capsule size, improving sensor precision, and reducing power needs were the primary challenges; these were resolved by employing micro sensors, optimized architecture, and an ASIC design that include power management, clock management, a programmable gain amplifier (PGA), an A/D converter (ADC), and a serial peripheral interface (SPI) communication unit. The ASIC has been fabricated in 0.18- µm CMOS technology with a die area of 5.0 mm × 5.0 mm. The wireless capsule integrating the ASIC controller measures Φ 11 mm × 26 mm. A data recorder and a workstation were developed, and 20 cases of human experiments were conducted in hospitals. Preprocessing in the workstation can significantly improve the quality of the data, and 76 original features were determined by mathematical statistics. Based on the 13 optimal features achieved in the evaluation of the features, the clustering algorithm can identify the patients who lack GI motility with a recognition rate reaching 83.3%.

The modified design of ring electrode quartz crystal resonator for uniform mass sensitivity distribution.

The mass sensitivity distribution curve of quartz crystal resonators (QCRs) with common circular electrodes is bell-shaped; however, a uniform mass sensitivity distribution is expected for highly accurate and repeatable measuring results. Pioneers designed a ring electrode QCR with a bimodal distribution curve of mass sensitivity, and an obvious concavity is presented between two peak points for a fundamental operating frequency of 10 MHz. The concavity is an obstacle to uniform mass sensitivity distribution, so eliminating the concavity is the goal of this study; two methods-changing overtone order and designing electrode geometry-are proposed to do so. An analytical theory for sensitivity distribution is introduced in this paper first. Analysis results show that the fifth overtone of 10 MHz is desirable for eliminating the concavity but with a drawback of sacrificing absolute mass sensitivity. The method of designing the electrode geometry can overcome this drawback and dot-ring and double-ring electrode geometries are proposed. When electrode parameters were selected properly, the maximum difference of mass sensitivity between two peak points was reduced by about 42.21% for dot-ring electrode QCR and 77.63% for double-ring electrode QCR compared with that of ring electrode QCR.