Search

Fentanyl and its derivatives are a type of potent opioid analgesics, with the characteristics of diverse structure, high toxicity, extremely low content, and high fatality rate. Currently, they have become one of the most serious problems in international drug abuse control due to their extensive use in drug production and use. Therefore, the development of a rapid, sensitive, and accurate method for detecting trace fentanyl is of great significance. In this study, in view of its complex structure and trace concentration, a new molecular imprinting electrochemical sensor was developed through molecular simulations followed by experimental validation to detect trace fentanyl. The process consisted of first obtaining the optimal functional monomer and its molar ratio through molecular simulations. The recognition sites of fentanyl-imprinted polymers were predicted to guide the synthesis of imprinted membranes with precision approach to ensure an efficient and accurate reaction process. Reduced graphene oxide (ErGO) was then deposited on glassy carbon electrode surface by electrochemical reduction to yield large numbers of active sites suitable for catalyzing reactions of fentanyl piperidine for promoted efficient electron transfer and amplified sensitivity of the sensor. Accordingly, fentanyl molecularly imprinted film was formed through one-step electropolymerization to yield greatly improved sensing selectivity due to the specific recognition of molecularly imprinted polymer. Under optimal experimental conditions, the fentanyl sensor showed an extended detection range of 3.84 × 10−9 mol L−1–1.72 × 10−6 mol L−1 and a detection limit of 1.28 × 10−9 mol L−1. A distinctive feature of this sensor is its molecularly imprinted polymerized membrane, which offers excellent specific recognition, thereby boosting the sensor's selectivity. Throughout the sensor's development process, molecular simulations were employed to steer the synthesis of molecularly imprinted polymers and predict the recognition sites of fentanyl-imprinted polymers. The experimental outcomes proved to align with the simulation data. The final sensor exhibited outstanding selectivity, repeatability, stability, and high sensitivity. The sensor was effectively used to reliably track fentanyl in human serum samples, with acceptable analytical reliability, suggesting its potential for practical applications. A novel electrochemical sensor with enhanced sensitivity and selectivity for the detection of fentanyl has been developed. This sensor was fabricated using molecular imprinting technology that involved molecular simulations to optimize the functional monomers and their molar ratio, and experimental validation to produce the imprinted film. The sensor incorporates reduced graphene oxide (ErGO) as a catalyst for enhancing electron transfer and sensitivity. This sensor has excellent detection capabilities and low detection limit. [Display omitted] • A novel high-sensitive fentanyl molecularly imprinted electrochemical sensor was developed. • Molecular simulation accurately guides the synthesis of fentanyl molecularly imprinted membranes. • ErGO provides abundant reactive sites to catalyze the electrochemical reaction of fentanyl. • This sensor is applied to monitor fentanyl in real human serum samples. [ABSTRACT FROM AUTHOR]

In this study, a simple electrochemical sensor based on l -arginine membrane (P-L-arg/GCE) was developed for rapid and sensitive detection of MDMA and MDA. A polyarginine membrane was obtained through one-step direct electropolymerization, which provides more reaction sites for the analyte and improves the sensitivity of the sensor. Following the optimized selection parameters, the MDMA detection range was established at 1.0 × 10−7∼3.5 × 10−5 mol L−1, with a detection limit of 3.3 × 10−8 mol L−1. Similarly, the detection range for MDA was established at 1.0 × 10−7∼5.3 × 10−5 mol L−1 with a detection limit of 3.3 × 10−8 mol L−1. Additionally, the potential oxidation mechanism of MDMA and MDA during the REDOX process was analyzed by cyclic voltammetry. Furthermore, the proposed sensor exhibited superior selectivity, excellent reproducibility, and satisfactory stability. The proposed sensors can be used for reliable monitoring of MDMA or MDA in human urine and hair samples, respectively, and it has acceptable analytical reliability and enormous potential for practical applications. A simple and highly sensitive electrochemical technique has been developed to quantitatively detect MDMA and MDA using P-L-arg/GCE. By means of this sensor, the electrochemical characteristics of both analytes were thoroughly investigated. The sensor demonstrates sound selectivity, repeatability, and long-term stability in the detection of MDMA and MDA. Furthermore, the method can be applied to the determination of MDMA and MDA in human urine and blood samples. [Display omitted] • A high-sensitive sensor for trace detection of ecstasy was designed. • The possible mechanisms of MDMA and MDA were deduced. • The sensor exhibited a wide detection range and low detection limit. • The sensor was successfully applied to the detection of MDMA and MDA in human serum. [ABSTRACT FROM AUTHOR]

A novel electrochemical method has been developed, based on a covalent organic framework (COF) and reduced graphene oxide (rGO), to detect fentanyl and alfentanil. COF nanomaterials with chrysanthemum morphology obtained by solvothermal reaction contain rich active sites for electrochemical catalytic reaction, thus improving the detection performance of the designed sensor. Reduced graphene oxide improves the sensor's sensitivity due to enhanced electron transfer. Under optimized experimental conditions, the fabricated electrode presents a linear range of 0.02 to 7.26 μM for alfentanil and 0.1 to 6.54 μM for fentanyl, with detection limits of 6.7 nM and 33 nM, respectively. In addition, the sensor possesses excellent selectivity, outstanding reproducibility, and acceptable stability. The proposed sensor is feasible for the reliable monitoring of fentanyl and alfentanil in human serum samples, with acceptable reliability and high potential in real-world applications. Finally, the electrochemical characteristic fingerprint of fentanyl is investigated by studying the electrochemical behavior of alfentanil and fentanyl on the electrode surface. [ABSTRACT FROM AUTHOR]

The purpose of our studies was to systematically assess the accuracy and clinical value of plasma calcitonin in patients with liver failure complicated with bacterial infection. In this study, we included prospective observational studies or randomized controlled trials on PCT. The quality of the studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Heterogeneity, pooled diagnostic odds ratio (DOR), pooled sensitivity, pooled specificity, pooled positive likelihood ratio, pooled negative likelihood ratio, the area under the summary receiver operating characteristic curve (SROC), and metaregression analysis were performed using Stata16.0 software. Consequently, the studies revealed substantial heterogeneity (I2 = 96, 95% confidence interval (95% CI) = 94–99). The results of meta-analysis using random effect models suggested that the combined DOR was 10.67 (95% CI = 3.73–30.53). In addition, the threshold effect analysis showed that the threshold effect was 0.23 and the correlation coefficient was −0.48, indicating that there was no threshold effect. In the forest map, the DOR of each study and the combined DOR are not distributed along the same line, and Q = 2.2 × 1014, P ≤ 0.001. Furthermore, the metaregression analysis of PCT study design, bacterial infection site, and mean age displayed that the P values were >0.05. The combined sensitivity was 0.77 (95% CI = 0.54–0.90), the combined specificity was 0.76 (95% CI = 0.70–0.82), the combined positive likelihood ratio was 3.25 (95% CI = 2.33–4.52), the combined negative likelihood ratio was 0.30 (95% CI = 0.14–0.67), and the combined AUC was 0.80 (95% CI = 0.76–0.83). In conclusion, PCT has moderate diagnostic value for adult liver failure complicated with bacterial infection, and it is a better auxiliary diagnostic index for liver failure with bacterial infection. However, the results of procalcitonin must be carefully interpreted combined with medical history, physical examination, and microbiological assessment. [ABSTRACT FROM AUTHOR]

The selective adsorption of palladium from wastewater is a feasible solution to solving palladium pollution and resource scarcity. Because traditional solvent extraction methods often involve the use of considerable amounts of organic solvents, research is focused on investigating adsorption techniques that can selectively remove palladium from wastewater. In this paper, the magnetic composite Fe 3 O 4 @MnO 2 @ZIF-67 was synthesized and its performance for the adsorption of Pd(II) in acidic water was investigated. Fe 3 O 4 @MnO 2 @ZIF-67 was characterized by various analytical methods such as TEM, SEM, EDS, BET, XRD, FTIR, zeta potential analysis, VSM, and TGA. The effects of palladium ion concentration, contact time, pH, and temperature on adsorption were evaluated. The kinetics were shown to follow the pseudo-second-order kinetic model and Elovich model, and the rate-limiting step was chemisorption. Thermodynamic studies showed that increasing the temperature promoted the adsorption of Pd(II), and the maximum uptake capacity of Fe 3 O 4 @MnO 2 @ZIF-67 for Pd(II) was 531.91 mg g−1. Interestingly, Fe 3 O 4 @MnO 2 @ZIF-67 exhibited superior selectivity for Pd(II) in the presence of Ir(IV), Pt(IV), and Rh(III). The adsorbent can be used repeatedly for selective adsorption of palladium. Even at the fifth cycle, the uptake rate of Pd(II) remained as high as 83.1%, and it showed a favorable adsorption capacity and selectivity for Pd(II) in real metallurgical wastewater. The adsorption mechanism was analyzed by SEM, FTIR, XRD, XPS, and DFT calculations, which indicated that electrostatic interactions and coordination with nitrogen-containing groups were involved. Fe 3 O 4 @MnO 2 @ZIF-67 is a promising adsorbent for the efficient adsorption and selective separation of palladium ions. [Display omitted] • A novel hydrangea-like super composite Fe 3 O 4 @MnO 2 @ZIF-67 was synthesized. • The maximum uptake capacity of Fe 3 O 4 @MnO 2 @ZIF-67 for Pd(II) is as high as 531.91 mg g−1. • Adsorbent exhibited superior selectivity for Pd(II) in actual metallurgical wastewater. • Electrostatic and coordination interactions are involved in the selective adsorption of Pd(II) by FMZ-67. [ABSTRACT FROM AUTHOR]

Flower-like TpTa-COF was synthesized by the one-step solvothermal method, and a novel electrochemical platform for separation and simultaneous sensitive detection of trace Pb(II) and Cd(II) in surface water was constructed based on TpTa-COF. The proposed sensor has the advantages of low detection limit, high sensitivity, and good stability, and has been successfully applied to the determination of Pb (II) and Cd(II) in two actual water samples. [Display omitted] • Flower-like TpTa-COF was synthesized by the simple solvent method for the first time. • TpTa-COF can provide abundant active sites for trace detection of Pb(II) and Cd(II). • The sensor exhibited a wide detection range and low detection limit. • The detection mechanism of TpTa-COF was explored through XPS and simulation calculation. Heavy metal pollution in aquatic environment poses an enormous risk to ecosystems and human health. In this study, a flowerlike covalent organic framework (TpTa-COF) was synthesized by one-step solvothermal method with 2,4,6-triformylphloroglucinol (Tp) and 4, 4-diamino-tribiphenyl (Ta) as building elements. Then it was used as an effective trap to establish an electrochemical sensing platform for simultaneously sensitive detection of trace Pb(II) and Cd(II) in water. This three-dimensional flower-shaped structure exhibited exceptional adsorption capacity, large surface area, high stability, and all of which enhanced the detection sensitivity of the sensor and facilitated full contact between ions and substrate. The high oxygen content in the structure provided abundant active sites for Pb(II) and Cd(II), further enhancing its electrochemical response. The constructed sensor exhibited a linear response to Pb(II) within the concentration range of 3–60 µg/L under the optimal conditions, with a detection limit of 0.16 µg/L. Similarly, a linear response was observed for Cd(II) in the concentration range of 5–60 µg/L, with a detection limit of 0.29 µg/L. Low detection limits, excellent sensitivity, and strong stability were all features of the suggested approach. It has been successfully employed in determining Pb(II) and Cd(II) concentrations in two actual water samples. XPS, SEM-EDS mapping, and density functional theory calculations confirmed that TpTa-COF interacted with metal ions mainly via coordination with carbonyl oxygen atoms in the structure. Overall, these findings will broaden the applications of COF in the field of chemical analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] Overexploitation of nature by humans has led to an increasingly serious issue of heavy-metal water pollution. To reduce the threat of water pollution to humans and the environment, it is imperative to develop or improve the water treatment technology for heavy-metal-containing wastewater. Functionalized Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 MNPs) have been widely used as effective adsorbents for the removal of heavy-metal ions from water owing to their high efficiency, low cost, selective adsorption ability, and recyclability. In this study, Fe 3 O 4 @DA-DMSA magnetic nanoparticles (FDDMs) were prepared by the functionalization of Fe 3 O 4 MNPs with environmentally friendly dopamine (DA) and a heavy-metal detoxifying agent such as 2,3-dimercaptosuccinic acid (DMSA) for the efficient and rapid adsorption of Pb2+, Cu2+, and Cd2+, with maximum adsorption capacities of 187.62, 63.01, and 49.46 mg/g, respectively. FDDMs exhibited the best ability to remove Pb2+ with a maximum adsorption capacity than that of the most reported Fe 3 O 4 MNP-related adsorbents. In actual wastewater and multi-component simulated water samples contaminated with Pb2+, Cu2+, and Cd2+, the as-prepared adsorbent maintained a good removal ability for Pb2+ with low influence by ionic strength and interfering ions, as well as exhibited an excellent selectivity. According to the results of batch experiments and X-ray photoelectron spectroscopy (XPS) analysis of the adsorbent before and after adsorption, the adsorption mechanism of the adsorbent for the removal of heavy-metal ions mainly involves coordination and ion exchange. In addition, the adsorbent exhibited a good regeneration performance. Therefore, FDDMs can be considered as a promising adsorbent for the treatment of heavy-metal wastewater. [ABSTRACT FROM AUTHOR]

In order to improve the effective guidance of martial arts movements, a decomposition method of martial arts movements based on image recognition is proposed. First of all, visual image target sampling of martial arts action is performed, and most of the noise background is eliminated through morphological gradient operation. Then, the contour edge of the human body is obtained, the contour edge of each frame of the video is extracted, and the accumulation is realized in the same image. Using accumulation, the edge image calculates the grid-based HOG to obtain the image action feature vector. Secondly, using the improved dynamic time warping theory combined with the characteristics of the angle change of each joint under the action time sequence, the joint change sequence among various martial arts movements can be identified in order to realize the decomposition process of martial arts actions based on image recognition. The experimental results show that the use of image recognition can effectively decompose martial arts movements. [ABSTRACT FROM AUTHOR]

Radiata pine wood (W) was modified with acetic anhydride and glutaraldehyde (GA) resulting in WAc and WGA to various weight percent gains (WPGs), whereas in WAc the effect is due to grafting and in WGA, crosslinking. The heat of vaporization of bound water (BW) of the modified woods was studied by differential scanning calorimetry (DSC) and the mass loss (due to water loss) of the samples by thermogravimetry (TG). The temperature program was in both cases from 25 to 40°C with 10°C min−1. The adsorbed or condensed water in wood were observed via low-field nuclear magnetic resonance (LFNMR). At a comparable WPG level, the LFNMR analysis showed that the interaction of water with WGA was stronger than that with WAc. In both modified woods, a considerable reduction in the vaporization heat of BW was visible due to cell wall hydrophobization and bulking. The reduction of condensed water in micropores was lower for WGA than WAc, probably because BW needs more energy to evaporate from the crosslinked stiff WGA cell walls. [ABSTRACT FROM AUTHOR]