A Portable Integrated Electrochemical Sensing System for On-Site Nitrite Detection in Food.

Ensuring an appropriate nitrite level in food is essential to keep the body healthy. However, it still remains a huge challenge to offer a portable and low-cost on-site food nitrite analysis without any expensive equipment. Herein, a portable integrated electrochemical sensing system (IESS) is developed to achieve rapid on-site nitrite detection in food, which is composed of a low-cost disposable microfluidic electrochemical patch for few-shot nitrite detection, and a reusable smartphone-assisted electronic device based on self-designed circuit board for signal processing and wireless transmission. The electrochemical patch based on MXene-Ti3C2Tx/multiwalled carbon nanotubes-cyanocobalamin (MXene/MWCNTs-VB12)-modified working electrode achieves high sensitivity of 10.533 µA mm-1 and low nitrite detection limit of 4.22 µm owing to strong electron transfer ability of hybrid MXene/MWCNTs conductive matrix and high nitrite selectivity of VB12 bionic enzyme-based ion-selective layer. Moreover, the portable IESS can rapidly collect pending testing samples through a microfluidic electrochemical patch within 1.0 s to conduct immediate nitrite analysis, and then wirelessly transmit data from a signal-processing electronic device to a smartphone via Bluetooth module. Consequently, this proposed portable IESS demonstrates rapid on-site nitrite analysis and wireless data transmission within one palm-sized electronic device, which would pave a new avenue in food safety and personal bespoke therapy.

Safe Trajectory Planning for Incremental Robots Based on a Spatiotemporal Variable-Step-Size A* Algorithm.

In this paper, a planning method based on the spatiotemporal variable-step-size A* algorithm is proposed to address the problem of safe trajectory planning for incremental, wheeled, mobile robots in complex motion scenarios with multiple robots. After constructing the known conditions, the spatiotemporal variable-step-size A* algorithm is first used to perform a collision-avoiding initial spatiotemporal trajectory search, and a variable time step is utilized to ensure that the robot completes the search at the target speed. Subsequently, the trajectory is instantiated using B-spline curves in a numerical optimization considering constraints to generate the final smooth trajectory. The results of simulation tests in a field-shaped, complex, dynamic scenario show that the proposed trajectory planning method is more applicable, and the results indicate higher efficiency compared to the traditional method in the incremental robot trajectory planning problem.

Correlation Between Brain Structure Atrophy and Plasma Amyloid-ß and Phosphorylated Tau in Patients With Alzheimer's Disease and Amnestic Mild Cognitive Impairment Explored by Surface-Based Morphometry.

Objective: To investigate the changes in the cortical thickness of the region of interest (ROI) and plasma Aß40, Aß42, and phosphorylated Tau (P-Tau) concentrations in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) as the disease progressed with surface-based morphometry (SBM), to analyze the correlation between ROI cortical thickness and measured plasma indexes and neuropsychological scales, and to explore the clinical value of ROI cortical thickness combined with plasma Aß40, Aß42, and P-Tau in the early recognition and diagnosis of AD. Methods: This study enrolled 33 patients with AD, 48 patients with aMCI, and 33 healthy controls (normal control, NC). Concentration changes in plasma Aß42, Aß40, and P-Tau collected in each group were analyzed. Meanwhile, the whole brain T1 structure images (T1WI-3D-MPRAGE) of each group of patients were collected, and T1 image in AD-aMCI, AD-NC, and aMCI-NC group were analyzed and processed by SBM technology to obtain brain regions with statistical differences as clusters, and the cortical thickness of each cluster was extracted. Multivariate ordered logistic regression analysis was used to screen out the measured plasma indexes and the indexes with independent risk factors in the cortical thickness of each cluster. Three comparative receiver operating characteristic (ROC) curves of AD-aMCI, AD-NC, and aMCI-NC groups were plotted, respectively, to explore the diagnostic value of multi-factor combined prediction for cognitive impairment. The relationship between cortical thickness and plasma indexes, and between cortical thickness and Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores were clarified by Pearson correlation analysis. Results: Plasma Aß40, Aß42, and P-Tau proteins in the NC, aMCI, and AD groups increased with the progression of AD (P < 0.01); cortical thickness reductions in the AD-aMCI groups and AD-NC groups mainly involved the bilateral superior temporal gyrus, transverse temporal gyrus, superior marginal gyrus, insula, right entorhinal cortex, right fusiform gyrus, and cingulate gyrus. However, there were no statistical significances in cortical thickness reductions in the aMCI and NC groups. The cortical thickness of the ROI was negatively correlated with plasma Aß40, Aß42, and P-Tau concentrations (P < 0.05), and the cortical thickness of the ROI was positively correlated with MMSE and MoCA scores. Independent risk factors such as Aß40, Aß42, P-Tau, and AD-NC cluster 1R (right superior temporal gyrus, temporal pole, entorhinal cortex, transverse temporal gyrus, fusiform gyrus, superior marginal gyrus, middle temporal gyrus, and inferior temporal gyrus) were combined to plot ROC curves. The diagnostic efficiency of plasma indexes was higher than that of cortical thickness indexes, the diagnostic efficiency of ROC curves after the combination of cortical thickness and plasma indexes was higher than that of cortical thickness or plasma indexes alone. Conclusion: Plasma Aß40, Aß42, and P-Tau may be potential biomarkers for early prediction of AD. As the disease progressed, AD patients developed cortical atrophy characterized by atrophy of the medial temporal lobe. The combined prediction of these region and plasma Aß40, Aß42, and P-Tau had a higher diagnostic value than single-factor prediction for cognitive decline.

The Levels of Amyloid ß-Protein and P181 in Peripheral Blood of Patients with Alzheimer's Disease Combined with Helicobacter pylori Infection and Their Clinical Significance.

OBJECTIVE: To analyze the levels of amyloid ß-protein and P181 in peripheral blood of patients with Alzheimer's disease combined with Helicobacter pylori infection and their clinical significance. METHOD: From January 2019 to June 2020, 59 patients were enrolled in this experiment including the AD group with 27 patients and the normal control group with 32 patients. The patients were divided into two groups: Alzheimer's disease (AD) group (n = 27) and control group (n = 32), collecting the general data of patients, analyzing the diagnostic specificity and sensitivity of serum p-tau181 and Aß42 and their influence on prognosis, and comparing the serum Aß42 and p-tau181 concentrations for different HP infection degrees. RESULT: Single diagnostic sensitivity of Aß42, p-tau181, and Aß42 combined p-tau181 was 0.863, 0.854, and 0.972, respectively, and their specificity was 0.048, 0.206, and 0.305, respectively. Compared with the single diagnosis of serum Aß42 and p-tau181, the combined diagnosis has higher sensitivity and specificity (P < 0.05); age, years of education, serum Aß42, and p-tau181 are factors affecting the prognosis of patients with Alzheimer's disease combined with Helicobacter pylori infection; the concentration of Aß42 in the control group was higher than that in the AD group, there was a statistical difference in the Aß42 concentration between the two groups (P < 0.05), and there was no statistical difference in the concentration of p-tau181 between the two groups (P > 0.05); the HP positive infection rate of the AD group and the control group was 63.0% and 35.7%, respectively. The HP negative infection rate of the AD group and the control group was 37.0% and 64.3%, respectively. Compared with the control group, the positive rate of HP in the AD group was higher, and the difference was statistically significant (P < 0.05); compared with HP-negative patients, HP-positive patients had a higher Aß42 concentration, and the difference was statistically significant (P < 0.05). The concentration of p-tau181 in the two groups was not statistically significant (P > 0.05); Aß42 gradually increases with increasing HP infection degree, and there are significant differences in serum Aß42 levels between different degrees of infection. However, the level of serum p-tau181 does not change significantly with the increase of infection. CONCLUSION: There are significant alterations in the expression levels of Aß42 and p-tau181 in peripheral blood of AD patients, and the levels of Aß42 are related to HP infection; Aß42 and p-tau181 are potential biomarkers for AD diagnosis and treatment.

Tunable Electronic Memory Performances Based on Poly(Triphenylamine) and Its Metal Complex via a SuFEx Click Reaction.

A triphenylamine derivative decorated with an azobenzene group (TDA) was synthesized via a SuFEx click reaction and its polymer, poly(triphenylamine) (PTDA), was polymerized through a redox polymerization. More interestingly, its polymeric metal complex, PTDA-Fe, can be simply obtained via one-pot reaction between TDA and FeCl3 owing to TDA showing a strong affinity to the FeIII ion. The sandwich memory device based on PTDA nanofilms as active layers exhibited a binary memory performance. However, the memory device based on its polymeric metal complex exhibited a unique ternary memory behavior. The different memory performances should come from the different conductive mechanism. The mechanism of such ternary memory devices is illustrated based on both the theoretical calculation and experiments. Our work provides new insights into the preparation of novel materials for multilevel memory devices.