Determination of Acetylcholinesterase Activity Based on Ratiometric Fluorescence Signal Sensing.

Acetylcholinesterase (AChE) plays an important role in the treatment of human diseases, environmental security and global food supply. In this study, the simple fluorescent indicators and MnO2 nanosheets were developed and integrated to establish a ratiometric fluorescence sensing system for the detection of AChE activity. Two fluorescence signals could be recorded independently at the same excitation wavelength, which extended the detection range and enhanced the visibility of results. Fluorescence of F-PDA was quenched by MnO2 nanosheets on account of inner filtering effect. Meanwhile, the nonfluorescent OPD was catalytically oxidized to 2,3-diaminophenazine by MnO2 nanosheets. The acetylcholine (ATCh) was catalytically hydrolyzed by AChE to enzymatic thiocholine, which decomposed MnO2 to Mn2+, recovered the fluorescence of F-PDA and reduced the emission of ox-OPD. Utilizing the fluorescence intensity ratio F468/F558 as the signal readout, the ratiometric fluorescence method was established to detect AChE activity. Under the excitation wavelength of 410 nm, the ratio F460/F558 against the AChE concentration demonstrated two linear relationships in the range 0.05 -1.0 and 1.0-50 U·L- 1 with a limit of detection (LOD) of 0.073 U·L- 1. The method was applied to the detection of AChE activity and the analysis of the inhibitor Huperzine-A. Due to the advantages of high sensitivity and favorable selectivity, the method possesses an application prospect in the activity deteceion of AChE and the screening of inhibitors.

Magnetic nanoparticles immobilized thrombin ligand fishing to screen thrombin inhibitors in natural products.

In this study, thrombin was immobilized with magnetic particles modified by glutaraldehyde. The changes in secondary structures of immobilized enzyme revealed an increment in conformational rigidity and stability, which can be reflected in temperature and pH stability as well as the tolerance of organic reagents. The optimal reutilization times of magnetic particle immobilized thrombin were 7 times, and the half-life of enzyme activity preserved at room temperature was 5 days, which was 2.5 times higher than that of free enzyme. Ligusticum chuanxiong and Anemarrhenae Rhizoma with high enzyme inhibitory activity were selected for primary screening, and six potential inhibitors of thrombin were identified by HPLC/MS. The results showed that three compounds in Anemarrhenae Rhizoma had better predictive thrombin inhibitory activity. Through the in vitro thrombin activity inhibition experiment, it was also verified that mangiferin and neo-mangiferin had an ideal thrombin activity inhibition effect, which was consistent with the results of molecular docking.

Development of a rapid and ultrasensitive magnetic chemiluminescence immunoassay for the detection of adiponectin and its clinical application.

Adiponectin (ADPN), which serum/plasma adiponectin levels are closely associated with insulin resistance and type 2 diabetes, and lower adiponectin levels predict an increased risk of diabetes, is a strong indicator of diabetes risk in people at high risk of diabetes in different races. Using the unique principle and performance advantages of chemiluminescence immunoassay (CLIA), an ADPN-CLIA method with high sensitivity, high specificity and wide detection range was established based on the principle of two-steps method of sandwich-type, with the magnetic particles (MPs) as the solid phase carrier and acridinium ester (AE) as the chemiluminescence reaction system. The selection of the main raw materials required, the preparation conditions of MPs-coated antibodies, the methods of AE-labeled antibodies, sample requirements and reaction modes were optimized and evaluated. AE labeling experiment was successfully performed with the labeling efficiency of 8.366 and the antibody utilization rate of 96.8%. The chemiluminescent immunoassay for ADPN had a good linear relationship from 0 ng/mL to 250 ng/mL (R2 =0.9993), with the detection limit of 0.05 ng/mL. The coefficient of variation (CV) of intra-assay and inter-assay precision were both less than 5% respectively. The recovery rates for accuracy were from 91.26% to 107.46%. The comparison experiment of 80 clinical serum samples between the developed ADPN-CLIA with the immunoturbidimetry showed that the correlation coefficient was 0.956, and the Bland-Altman analysis showed that the limits of agreement were - 0.364 and 0.433.

Electric vehicle routing models and solution algorithms in logistics distribution: A systematic review.

With the development of green logistics and the promotion of new energy vehicle development policies domestically and abroad, electric vehicles have been put into logistics and distribution as an alternative to traditional fuel vehicles. The Electric Vehicle Routing Problem (EVRP) has attracted widespread attention from the academic community. This paper comprehensively examines the latest research progress on electric vehicle routing models and solution algorithms in logistics and distribution. Firstly briefly introduces EVRP models considering battery losses; secondly, based on the composition of the EVRP objective function and constraints, EVRP models are classified into four types: EVRP considering load and battery life constraints, EVRP with a time window and considering charging strategies, the study of vehicle routing problems for hybrid fleets, and EVRP combined with charging/swapping station location. Then, briefly introduce exact algorithms, traditional heuristics, meta-heuristics, and hybrid algorithms for solving EVRP models. Moreover, it analyzes the main meta-heuristics that are more widely used. Finally, this review points out the development trend of EVRP theoretical methods.

Localized Surface Plasmon Resonance Induced Band Gap Regulation Governing the Excellent Photocatalytic Performance of Ag/g-C3N4 Heterostructure.

It is an efficient mode to optimize photocatalytic performance of semiconductors by the localized surface plasmon resonance (LSPR) effect through constructing composites with noble metal nanoparticles, nevertheless, the understanding for the essential mechanism, especially the LSPR effect on band gap engineering or free radicals, is not clear. Herein, Ag nanoparticles (Ag NPs) were decorated on popular used semiconductors, graphitic carbon nitride (g-C3N4), through a microemulsion route. As expected, Ag/g-C3N4 hybrid materials demonstrated outstanding photocatalytic decomposition of organic dyes, including methyl orange, phenol and rhodamine B, in which the photocatalytic efficiency of the composite with the optimal ratio of Ag content was 3.37 times higher than that of pristine sample. The mechanism for the better photocatalytic action was attributed to the localized surface plasmon resonance (LSPR) effect, narrow band gap and low valance band position originated from Ag NPs, which resulted in superior visible-light adsorption and the formation of _OH with strong oxidation. As well, because of the synergy between Ag NPs and g-C3N4, faster separation of the photogenerated charges and efficiently utilization of the ·OH and ·O-2 generated from hole and electron are realized simultaneously. Ultimately, our results offer a extremely understanding of superior photocatalytic property caused by the LSPR effect.

Evaluation of apparent diffusion coefficient measurements of brain injury in type 2 diabetics with retinopathy by diffusion-weighted MRI at 3.0 T.

Diabetes is often associated with impairments in brain functioning. However, the injury of specific functioning areas of the brain is not clear. To address this problem, the present study was designed to investigate possible brain functioning change in specific brain areas, particularly in areas associated with vision function, in patients with proliferative and nonproliferative diabetic retinopathy (PDR and NPDR) using the diffusion-weighted imaging technology. Conventional MRI was performed in 45 diabetic patients, 30 of whom had diabetic retinopathy (DR) involvement (half PDR, and half NPDR) and 15 of whom were diabetic patients without retinopathy and with normal ophthalmologic examination. The apparent diffusion coefficient (ADC) values were calculated in the orbitofrontal cortex (OFC), cingulated gyrus, thalamus, dorsomedial and dorsolateral frontal cortex, and corona radiate. The ADC values of the OFC, cingulated gyrus, and visual cortex were significantly increased in patients with PDR and NPDR compared with both patients without retinopathy and the control group (P<0.01). The ADC values of the OFC, cingulated gyrus, and visual cortex were significantly increased in patients with PDR compared with NPDR. The duration of disease and values of hemoglobin A1c were significantly correlated with ADC values of the OFC, cingulated gyrus, and visual cortex, respectively (P<0.01 or <0.05). We observed significantly increased ADC values of the visual center (OFC, cingulated gyrus, and visual cortex), supporting the association between DR and impairment in brain functioning. Diffusion-weighted imaging may serve to assess subclinical neurological involvement in DR, even when brain structural changes are absent.

[Morphology of olfactory bulb, olfactory tract blood supply affected by anthrosclersis and its clinical significance].

OBJECTIVE: In order to provide morphological evidences for olfactory defect cased by olfactory bulb, olfactory tract ischemia, the origins, numbers, distributions and pathological changes about olfactory bulb, olfactory tract arteries were studied. METHOD: The distributions and pathological changes of olfactory bulb, olfactory tract arteries in 80 sides of adult brain specimens were observed with operation microscope, among which the nourishing arteries and nerve of olfactory tract in two sides aged from 60 to 70 were observed pathohistologically. RESULT: The blood supply of olfactory bulb, olfactory tract comes mainly form artery cerebral and posterior communicainy. 10% of these 60 sides arteries were of multi-branch. 86.3% of them had atheroselerosis. 25.0% of the olfactory bulb and olfactory tract artery were blocked or narrow, and pathological changes in olfactory nerve such as atrophy were observed. CONCLUSION: Excluding other diseases, the olfactory defect in different degree of patients over 60 years old were caused possibly by atheroselerosis of the arteries at base of the brain.