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In recent years, redox reactions have harnessed light or mechanical energy to enable the formation of chemical bonds. We postulated a complementary approach that electromagnetic induction could promote the redox reaction of organic molecules using a rotating magnetic field and metal rods. Here, we report that electromotive force activates the redox-active trifluoromethylating reagents. This magnetoredox system can be applied to the trifluoromethylation of heteroarenes with high regioselectivity and hydrotrifluoromethylation of alkenes without the need for catalysts and organic additives.
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Hydrogels have been widely used in various fields due to their diverse properties and flexible preparation methods. However, limited by the open network structure, hydrogels inevitably lose water in air or absorb water in aqueous solution, resulting in the loss of intrinsic functions, which severely hinders their practical applications. To address this issue, a general strategy was developed by subsequently modifying the surface of hydrogels with branched polyethyleneimine (PEI) and (3-(methacryloxy)propyl)trimethoxysilane (MPS) to covalently construct a dense cross-linked siloxane layer on the hydrogel surface. As a proof of concept, poly(2-(dimethylamino)ethyl methacrylate)/sodium alginate (PDMAEMA/SA) hydrogels were chosen as the model hydrogels to verify the feasibility of this strategy. The hydrogels adsorbed PEI to form amino-rich surfaces through hydrogen bonding, followed by covalently grafting MPS through rapid and catalyst-free mutual chemical reactions between acrylates and amine groups, as well as the hydrolysis of MPS. After modification, robust hydrophobic surfaces were successfully fabricated on the hydrophilic hydrogels. The modified hydrogels exhibited extraordinary anti-swelling and water-retention abilities. As the most typical intrinsic properties of hydrogels, the conductivity and sensing performance were well preserved. The strategy reported here provides a new insight into the construction of hydrogels with anti-swelling and water-retention abilities.
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1,1,2,2-Tetrafluoroethyl-containing molecules are of potential importance in drug discovery, but the efficient synthesis of such compounds is still relatively unexplored due to the lack of readily available reagents for the incorporation of the HCF2CF2 group. Herein, we introduce a new reagent, zinc 1,1,2,2-tetrafluoroethanesulfinate, which can be useful for the oxidative tetrafluoroethylation of arylboronic acids and heteroarenes as well as for a novel photoredox, three component hydro-tetrafluoroethylation of two alkenes of complementary reactivity.
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Herein, we present a Ni-catalyzed direct cross-coupling of heteroaromatic thioethers with aryl iodides via selective C(sp2)-S bond cleavage under reductive conditions, thereby providing various biaryl frameworks with high efficiency. Mechanistic studies suggested Mo(CO)6 played a crucial role in facilitating the activation of the C(sp2)-S bond. This protocol demonstrated a wide substrate scope, operational simplicity, and good functional group compatibility. Furthermore, the utility of this reaction was highlighted by facile scale-up and sequential modification of heteroaryl frameworks.
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EMM (electromagnetic mill)-promoted Pd-catalyzed solid state intramolecular Heck-type cyclization/boronation and Suzuki couplings are reported. Compared to previous mechanochemistry that constructed one chemical bond through a cross-coupling reaction, this strategy realizes cascade transformation along with multiple chemical bond formation. This conversion does not require organic solvents or additional heating, and it shows a good substrate scope and high functional group tolerance.
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BACKGROUND: Artificial intelligence is a growing phenomenon that will soon facilitate wide-scale changes in many professions, and is expected to play an important role in the field of medical education. This study explored the realistic feelings and experiences of nursing undergraduates participating in different stages of artificial intelligence + project task driven learning, and provide a basis for artificial intelligence participation in nursing teaching. METHODS: We conducted face-to-face semi-structured interviews with nursing undergraduates participating in Nursing Research Course which adopts artificial intelligence + project task driven learning from a medical university in Ningxia from September to November 2023, to understand their experience of using artificial intelligence for learning and the emotional changes at different stages. The interview guide included items about their personal experience and feelings of completing project tasks through dialogue with artificial intelligence, and suggestions for course content. Thematic analysis was used to analyze interview data. This study followed the COREQ checklist. RESULTS: According to the interview data, three themes were summarized. Undergraduate nursing students have different experiences in participating in artificial intelligence + project task driven learning at different stages, mainly manifested as diverse emotional experiences under initial knowledge deficiency, the individual growth supported by external forces during the adaptation period, and the expectations and suggestions after the birth of the results in the end period. CONCLUSIONS: Nursing undergraduates can actively adapt to the integration of artificial intelligence into nursing teaching, dynamically observe students' learning experience, strengthen positive guidance, and provide support for personalized teaching models, better leveraging the advantages of artificial intelligence participation in teaching.
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1,1,2,2-Tetrafluoroethyl-containing compounds are valuable structures due to their unique physicochemical properties, which have increasing potential application in drug discovery. However, synthetic methods for preparing such compounds are rare. Herein, we report the first use of 1,1,2,2-tetrafluoroethanesulfonyl chloride to introduce the HCF2 CF2 group into organic molecules via a three-component, radical tetrafluoroethyl-heteroarylation of alkenes with readily available quinoxalin-2(1H)-ones. This method provides a new and facile approach for late-stage functionalization of potential biologically active molecules.
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We herein report the first visible-light-induced hydromono- and difluoroalkylations of alkenes with inexpensive and easily accessible α-fluoro carboxylic acids. This metal-free protocol exhibits mild conditions, high efficiency, and excellent functional-group tolerance, providing a straightforward approach to mono- and difluoroalkylated alkanes. Moreover, the fluorine effect on the hydrofluoroalkylation reaction is discussed in detail.
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A Pd/Et3N·HI-catalyzed intramolecular C-H alkylation of indoles with epoxides was achieved to furnish N-fused indole frameworks (5-, 6-, and 7-membered rings) bearing an alcohol group. The conversion proceeded smoothly in the presence of a catalytic amount of Et3N·HI together with a palladium catalyst and exhibited great functional group tolerance. The employment of Et3N·HI not only avoids the prior preparation of alkyl halide substrates but also is the key to the high chemoselective ring-opening of epoxides. Preliminary mechanism explorations strongly support a radical pathway, and the catalytic cycle was established tentatively according to the mechanism investigation experiments.
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Compuestos Epoxi , Indoles , Alquilación , Catálisis , Compuestos Epoxi/química , Indoles/química , Paladio/químicaRESUMEN
The hepatitis B virus (HBV) can cause chronic hepatitis and hepatocellular carcinoma. Hepatitis B surface antigen (HBs-Ag) and Hepatitis B e-antigen (HBe-Ag) are key markers for the diagnosis of HBV. In this study, electrodeposited gold was used as a sensing platform. Three-dimensional (3D) SnO2-loaded graphene sheets functionalized by Thionine (Thi) and ferrocene (Fc) and hybridized by sea urchin-like bimetallic nanoparticles (GS-SnO2-BMNPs) were used as redox probes for labeling antibodies to fabricate sandwich-type immunosensors for the simultaneous determination of HBs-Ag and HBe-Ag. The bimetallic nanoparticles, gold hybrid platinum nanoparticles (Au@Pt) and L-cysteine-connected gold-silver nanoparticles (Ag-cys-Au), have large electroactive surface areas. They were prepared by an efficient and economical method. Additionally, the sea urchin morphology accelerates spatial utilization, thus increasing the number of combination sites. Therefore, the immune probe can load a mass of signal source molecules (Thi and Fc). Furthermore, GS-SnO2-BMNPs (GS-SnO2-Au@Pt and GS-SnO2-Ag-cys-Au) with excellent electrical conductivity and bimetallic synergy can enhance the square wave voltammetry (SWV) signal. SWV was used to record the electrochemical signal by scanning the potential from - 0.6 to 0.6 V (vs. SCE). The signal peaks resulted from the reduction reaction of Thi and Fc, and two signal peaks were completely separate. The peak position and current intensity reflect the identity and level of the corresponding antigens. Therefore, the simultaneous detection of two viral biomarkers was achieved by the proposed immunosensor. The fabricated immunosensor showed a linear concentration range for HBs-Ag (0.01-100 ng·mL-1) and HBe-Ag (0.01-100 ng·mL-1), with detection limits for HBs-Ag and HBe-Ag of 4.67 pg·mL-1 and 4.68 pg·mL-1, respectively. The RSD of HBs-Ag ranged between 2.0 and 4.4%and the recovery was in the range 98.7 to 99.4%. For HBe-Ag the RSD was between 2.6 and 3.3% andrecoveries in the range 99.2 to 100.5% were obtained.
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Antígenos de Superficie de la Hepatitis B/sangre , Antígenos e de la Hepatitis B/sangre , Virus de la Hepatitis B/química , Inmunoensayo/métodos , Anticuerpos Inmovilizados/inmunología , Anticuerpos Monoclonales/inmunología , Técnicas Electroquímicas/métodos , Compuestos Ferrosos/química , Oro/química , Grafito/química , Antígenos de Superficie de la Hepatitis B/inmunología , Antígenos e de la Hepatitis B/inmunología , Humanos , Límite de Detección , Nanopartículas del Metal/química , Metalocenos/química , Fenotiazinas/química , Plata/química , Compuestos de Estaño/químicaRESUMEN
A voltammetric sandwich immunoassay is described for the biomarker cardiac troponin I (cTnI). The gold nanocube-functionalized graphene oxide (AuNC/GO) is employed as a substrate to accelerate the electron transfer and to immobilize more primary antibodies. It also employs composite materials prepared from bimetallic gold/silver core-shell nanocubes and nitrogen and sulfur co-doped reduced graphene oxide as the signal amplifier. The introduction of N and S into GO enlarges the active surface and accelerates the electron transfer rate. Such unique characteristics render the material an effective support substrate to load more Au@AgNC and to immobilize an increasing number of second antibodies via Ag-N bonds. After specific binding with cTnI, the immunosensor was incubated in a labeled cTnI secondary antibody solution. The amperometric signal change is then measured at 0.34 V (vs. SCE) using o-phenylenediamine and hydrogen peroxide as an electrochemical probe. Response is linear in the concentration range from 100 fgâmL-1 to 250 ngâmL-1, and the detection limit is 33 fgâmL-1. Graphical abstract Schematic presentation of cardiac troponin I (cTnI) electrochemical immunosensor based on gold nanocube-functionalized graphene oxide (AuNC/GO) as substrate material, bimetallic gold/silver core-shell nanocubes and nitrogen and sulfur co-doped reduced graphene oxide (Au@AgNC/N, S-rGO) as signal amplifier, and hydrogen peroxide (H2O2) and o-phenylenediamine (o-PD) as redox probe.
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Técnicas Electroquímicas/métodos , Grafito/química , Inmunoensayo/métodos , Nanopartículas del Metal/química , Troponina I/sangre , Anticuerpos Inmovilizados/inmunología , Biomarcadores/sangre , Técnicas Electroquímicas/instrumentación , Electrodos , Oro/química , Humanos , Límite de Detección , Nitrógeno/química , Reproducibilidad de los Resultados , Plata/química , Azufre/química , Troponina I/inmunologíaRESUMEN
A pentacoordinate bis(difluoromethyl)silicate anion, [Me3 Si(CF2 H)2 ](-) , is observed for the first time by the activation of Me3 SiCF2 H with a nucleophilic alkali-metal salt and 18-crown-6. Further study on its reactivity by tuning the countercation effect led to the discovery and development of an efficient, catalytic nucleophilic difluoromethylation of enolizable ketones with Me3 SiCF2 H by using a combination of CsF and 18-crown-6 as the initiation system. Mechanistic investigations demonstrate that [(18-crown-6)Cs](+) [Me3 Si(CF2 H)2 ](-) is a key intermediate in this catalytic reaction.
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The electromagnetic mill (EMM) promoted mechanochemical solvent-free palladium-catalyzed borylation of aryl bromides using low palladium catalyst loading (0.05-0.5 mol %) was realized. This protocol exhibits many advantages, such as broad substrate scope, good functional group tolerance, short reaction times, no additional heating, and practical gram-scale synthesis. This EMM system not only showed excellent prospects for industrial application but also unlocked broad areas of solvent-free solid-state metal-catalyzed syntheses.
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For generating an interpretable deep architecture for identifying deep intrusion patterns, this study proposes an approach that combines ANFIS (Adaptive Network-based Fuzzy Inference System) and DT (Decision Tree) for interpreting the deep pattern of intrusion detection. Meanwhile, for improving the efficiency of training and predicting, Pearson Correlation analysis, standard deviation, and a new adaptive K-means are used to select attributes and make fuzzy interval decisions. The proposed algorithm was trained, validated, and tested on the NSL-KDD (National security lab-knowledge discovery and data mining) dataset. Using 22 attributes that highly related to the target, the performance of the proposed method achieves a 99.86% detection rate and 0.14% false alarm rate on the KDDTrain+ dataset, a 77.46% detection rate on the KDDTest+ dataset, which is better than many classifiers. Besides, the interpretable model can help us demonstrate the complex and overlapped pattern of intrusions and analyze the pattern of various intrusions.
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Neurología , Árboles de Decisión , Algoritmos , Minería de Datos , Descubrimiento del ConocimientoRESUMEN
Deep Residual Networks (ResNets) are prone to overfitting in problems with uncertainty, such as intrusion detection problems. To alleviate this problem, we proposed a method that combines the Adaptive Neuro-fuzzy Inference System (ANFIS) and the ResNet algorithm. This method can make use of the advantages of both the ANFIS and ResNet, and alleviate the overfitting problem of ResNet. Compared with the original ResNet algorithm, the proposed method provides overlapped intervals of continuous attributes and fuzzy rules to ResNet, improving the fuzziness of ResNet. To evaluate the performance of the proposed method, the proposed method is realized and evaluated on the benchmark NSL-KDD dataset. Also, the performance of the proposed method is compared with the original ResNet algorithm and other deep learning-based and ANFIS-based methods. The experimental results demonstrate that the proposed method is better than that of the original ResNet and other existing methods on various metrics, reaching a 98.88% detection rate and 1.11% false alarm rate on the KDDTrain+ dataset.
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Lógica Difusa , Redes Neurales de la Computación , AlgoritmosRESUMEN
A sandwich-type electrochemical immunosensor was designed utilizing ferrocene-functionalized cuprous oxide superparticles (Au/Fc@CuxO SPs) as the signal label and graphene supported by hollow carbon balls (HCNs-GR) as the substrate. The CuxO SPs possess a superparticle structure with synergistic properties of isotropy and promising catalytic activity. Ferrocene (Fc) was deposited on the CuxO SPs to act as the electronic transmission medium. The Au/Fc@CuxO SPs played a pivotal role in improving the sensitivity of the immunosensor. The graphene supported by hollow carbon balls (HCNs-GR) was used to modify the electrode surface. The embedding of hollow carbon nanospheres (HCNs) reduced the decrease of the effective surface area caused by the stacking of graphene nanotubes. Meanwhile, the load of carbon balls further increases the surface area of graphene, enabled HCNs-GR to immobilize antibodies more effectively, improved the sensitivity of the immunosensor. The proposed immunosensor showed a linear range from 500 fg/mL to 100 ng/mL, with the detection limit to 25.7 fg/mL.
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Técnicas Biosensibles , Cobre , Técnicas Electroquímicas , Inmunoensayo , MetalocenosRESUMEN
A mild and efficient method for direct C-H monofluoroalkylation of heteroarenes with easily accessible and inexpensive α-fluorocarboxylic acids has been developed. This silver-catalyzed reaction affords mono- and bis-monofluoroalkylated heteroarenes in good yields under mild conditions, and the solvent effect on the monofluoroalkylation reaction is discussed in detail.
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A palladium/norbornene cooperative catalyzed selective C-H bond amination of aryl iodides was explored, providing an efficient tool for constructing benzocyclic molecules. When ortho-substituted iodobenzene was involved, the C-H bond amination and following Heck cyclization efficiently delivered a 3-methyl-indole scaffold. On the other hand, we realized the controllable synthesis of monoaminated benzo-cyclobutanyl scaffold. The possible coordination of an installed terminal alkenyl group with palladium and steric hindrance were proposed to be responsible for the monoamination selectivity.
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As a specific biomarker, neuron-specific enolase (NSE) is an essential clinical indicator for diagnosing small cell lung cancer. In this paper, a sandwich-type electrochemical immunosensor was designed for the quantitative detection of NSE. AuPt nanoblock spherical nanoarchitectonics (AuPt NSNs), a bimetallic nanoparticle with a rugged morphology, were utilized as the substrate, which could enhance the electronic conduction and increase the immobilization capacity of the primary antibody (Ab1). Moreover, through a simple hydrothermal method, Au/CuxO@CeO2 was prepared as a spiny core-shell nanocube with cerium dioxide (CeO2) and gold nanoparticles (Au NPs) loading. The combination of Cu2O, CuO, and CeO2 showed favorable catalytic activity toward hydrogen peroxide (H2O2). Furthermore, the deposition of Au NPs on the spiny surface structure enhanced the specific surface area and biocompatibility, thereby rendering it more effective for loading the second antibody (Ab2). As the label material, the Au/CuxO@CeO2 achieved signal amplification and sensitive detection with the immunosensor. Under optimal conditions, the designed immunosensor possessed a broad linear range of 50 fg mL-1 to 100 ng mL-1 and a limit of detection of 31.3 fg mL-1, along with satisfactory performance in sensitivity, selectivity, and stability.
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Técnicas Biosensibles/métodos , Cerio/química , Oro/química , Límite de Detección , Nanoestructuras/química , Neuronas/enzimología , Fosfopiruvato Hidratasa/metabolismo , Anticuerpos Inmovilizados/química , Electroquímica , Peróxido de Hidrógeno/química , Modelos Lineales , Nanopartículas del Metal/químicaRESUMEN
Herein reported is a nickel-catalyzed reductive aryl thiocarbonylation of alkene via thioester group transfer strategy by using simple and readily available thioesters. In contrast to traditional activation of weaker C(acyl)-S bond, the C(acyl)-C bond of thioester was selectively cleaved to enable this reaction under mild conditions. Furthermore, this approach features operational simplicity and broad substrate scope, providing a complementary and practical route for thioester synthesis without requiring toxic thiol or CO gas.